Short Papers in the 

Geologic and Hydrologic 

Sciences, Articles 293-435 

i GEOLOGlCAL S.URVEY RESEARCH 1961 

1. 

GEOLOGICAL SURVEY PROFESSIONAL PAPER· 424-D 

Scientific notes and summarie; of investigations prepared by members of the Geologic, Water Resources, 

and Conservation Divisions in the fields of geology, 

hydrology, and allied sciences 

UNITED STATES GOVERNMENT PRINTING OFFICE, WAS.HINGTON : 1961 
UNITED STATES DEPARTMENT OF THE INTERIOR 

STEWART L. UDALL, Secretary 

GEOLOGIC SURVEY 

Thomas B. Nolan, Dirfctor 

For sale by the Superintendent of Documents, U.S. Government Printing Office 

Washington 25, D.C. 

'--..: 
• 

,. 

··' 

FOREWORD 

The scientific and economic results of work by the United States Geological Survey during 

the fiscal year 1961, .the 12 months ending June 30, 1961, are summarized in 4 volumes. This 

volume includes 143 short papers on subjects in the fields of geology, hydrology, and related 

sciences, prepared by members of the Geologic, "rater Resources, and Conservation Divisions 

of the Survey. Some are announcements of new discoveries or observations on problems of 

limited scope, which may or may not be described in greater detail subsequently. Others 

summarize conclusions drawn from more extensive or continuing investigations, which in large 

part will be described in greater detail in reports to be published at a later date. 

Professional Paper 424-A provides a synopsis of the more important new findings resulting from work during the fiscal year. Professional ~apers 424-B and 424-C contain additional short papers .like those in the present volume. 

THoMAs B. NoLAN, 

Director. 

III 

CONTENTS 

Page 

Foreword-------------------------------------------~--------------------------------------~------------------ Ill 

Geology of metalliferous deposits 

293. Potassic feldspathization and thorium deposition in the Wet Mountains, Colorado, by George Phair and Frances 

G·. Fisher____ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ D-1 

294. Structural framework of the Illinois-Kentucky mining district and its relation to mineral deposits, by A. V. Heyl, 

Jr., and M. R. Brock--------------------------------------------------------------------------------· 3 

295. Possible relation between hydrogen sulfide-bearing hydrocarbons in fault-line oil fields and uranium deposits in the 

southeast Texas Coastal Plain, by D. Hoye Eargle and Alice D. Weeks_____________________________________ 7 

296. "Relation of fold structures to distribution of lead and zinc mineralization in the Belmont and Calamine quadrangles, 

Lafayette County, Wisconsin, by WalterS. West and Harry Klemic ________________________________________ . 9 

Hydrologic studies 

297. Reservoir storage for short-period streamflow regulation, by G. N. Mesnier, R. E. Oltman, and W. B. Langbein____ 12 

298. H.eservoir storage-general solution of a queue model, by W. B. Langbein_~__________________________________ 13 

299. Origin of regressive ripples explained in terms of fluid-mechanic processes, by Alan V. Jopling___________________ 15 

300. The significance of the fall velocity and effective fall diameter of bed materials, by William L. Haushild, Daryl B. 

Simons, and Everett V. Richardson _________ ..: __________________________________________ :.._____________ _ _ 17 

301. Qualitative effects of temperature on flow phenomena in alluvial channels, by D. W. Hubbell and Khalid Al-Shaikh 

Ali------------------------------------------------------------------------------------------------- 21 

302. Dispersion-motivated fluctuations of ground-water levels in wells, by F. A. Kohout____________________________ 24 

303. Dispersion with oscillating flow in a granular material, by Willis K. Kulp _____________________________ ..: _ _ _ _ _ _ _ 26 

304. Chemical character of precipitation at Menlo Park, California, by H. C. Whitehead and J. H. Feth______________ 29 

305. Mechanical uniform packing of porous media, by Donald A. Morris and Willis K. Kulp________________________ 31 

Geology and hydrology of eastern United States 

306. Post-Cambrian .igneous rocks of the central craton, western Appalachian Mountains and Gulf Coastal Plain of the 

United States, by M. R. Brock and A. V. Heyl, Jr______________________________________________________ 33 

307. Underseepage along Levee 30, Dade County, Florida, by Howard Klein and C. B. Sherwood____________________ 36 

308. Sources of water in Styx an.d Echo Rivers, Mammoth Cave, Kentucky, by G. E. Hendrickson__________________ 41 

309. Volcanic rocks of Ordovician age in the Mount Chase ridge, Island Falls quadrangle, Maine, by E. B. Ekren_ _ _ _ _ _ 43 

310. Post-Carboniferous· deformation of metamorphic and igneous rocks near the Northern Boundary fault, Boston 

Basin, Massachusetts, by Norman P. Cuppels ___________ --------- _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ ____ _ _ _ ____ _ __ _ _ 46 

311. A regional fault in east-central Massachusetts and southern New Hampshire, by Robert F. Novotny_____________ 48 

312. Ground water in Eocene rocks in the Jackson dome area, Mississippi, by Joseph W. Lang______________________ 50 

, ... 313. Natural movement of ground water at a site on the Mullica River in the Wharton Tract, southern New Jersey, by S. M. Lang _____ ----- _____________________________ -------- ______________________________ ·____________ 52 

314. Variation in temperature of two streams on Long Island, New York, by Edward J. PluhowskL_________________ 55 

315. Effect of Lake St. Lawrence on ground water in the Beekmantown dolomite, northern St. Lawrence County, New · York, by Frank W. Trainer and Ralph C. Heath _____________________________________________________ :___ 58 

316. The Stokes and Surry Counties quartzite area, North Carolina-a window?, by Bruce Bryant and John C. Reed, Jr _ _ 61 

317. Hydrologic processes diluting and neutralizing acid streams of the Swatara Creek basin, Pennsylvania, by E. F. 

McCarren, J. W. Wark, and J. R. George______________________________________________________________ 64 

318. Correlation of end moraines in southern Rhode Island, by J. P. Schafer_ ______________________ ~ __ .____________ 68 

319. Residual sea water in the basement complex of the Fall Zone in the vicinity ·of Fredericksburg, Virginia, by Seymour 

SubitzkY------------------------------------------------------------------------------~------------ 71 

Geology and hydrology of western conterminous United St~tes 

320. Suggested magmatic differences between welded "ash" tuffs and welded crystal tuffs, Arizona and Nevada, by Ralph J. Roberts and Donald W. Peterson _______________________________ .:. ___________ ·_________________________ 73 

321. Effects of a buried anticline on ground water in Navajo sandstone in the Copper Mine-Preston Mesa area, Coconino 

County, Arizona, by N. E. McClymonds_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 79 

Flattening ratios of pumice fragments in an ash-flow sheet near Superior, Arizona, by Donald W. Peterson________ 82 ;-< 322. 

323. Landslides east of Funeral Mountains, nea.r Death Valley Junction, California, by Charles S. Denny______________ 85 

324. Compaction of montmorillonite-rich sediments in western Fresno County, California, by Robert H. Meade_______ 89 ~ 325. Surface-water hydrology of coastal basins of northern California, in relation to geology and topography, by S. E. 

Rantz------------------------------------~--------------------------------------------------------- 92 

v 
VI CONTENTS 

Geology and hydrology of western conterminous United States-Continued Page · 

326. Central vent ash-flow eruption, western San Juan Mountains, Colorado, by Robert G. Luedke and Wilbur 

S. Burbank----------------------------------------------------------------------------------------- J)-94 

327. Eight members of the Oak Sp:fing formation, Nevada Test Site and vicinity, Nye and Lincoln Counties, Neva.da, 

by E. N. Hinrichs and P. P. Orkild-------------------------------------------------------------------- 96 

328. Eleana formation of Nevada Test Site and vicinity,. Nye County, Nevada, by F. G. Poole, F. N. Houser, and P. 

P. Orkild-------------~----------------------------------------------------------------------------- 104 

329. Lake Lahontan stratigraphy and history in the Carson Desert (Fallon) area, Nevada, by R. B. Morrison__________ 111 

330. A suggested Pleistocene-Recent (Holocene) boundary for the Great Basin region, Nevada-Utah, by R. B. Morrison_ 115 

331. Hydrothermal alteration of rocks in two drill holes at Steamboat Springs, Washoe County, Nevada, by Gudmundur 

E. Sigvaldason and Donald E. White---- __ -- ______ ---------- __________ -_______________________________ 116 

332. Correlation of the deposits of Lakes Lahontan and Bonneville and the glacial sequences of the Sierra Nevada and 

Wasatch Mountains, California, Nevada, and Utah, by R. B. Morrison____________________________________ 122 

333. New evidence on the history of Lake Bonneville from an area south of Salt Lake City, Utah, by R. B. Morrison____ 125 

334. New evidence of the age of Lake Bonneville from the moraines. in Little Cottonwood Canyon, Utah, by G. M. Richmond----------------------------------------~----------------------------------------------------- 127 

335. Magnitude of thrust faulting in northern Utah, by Max D. Crittenden, Jr _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 128 

336. Subdividing the Jordan Valley ground-water basin, Utah, by I. Wendell Marine______________________________ 132 

337. Potash-be~ring evaporite cycles in the salt anticlines of the Paradox basin, Colorado and Utah, by Robert J. Hite_ _ _ _ 135 

338. Cretaceous rocks in Lea County, New Mexico, by Sidney R. Ash and Alfred Clebsch, Jr________________________ 139 

339. Distribution of moisture in soil and near-surface tuff on the Pajarito Plateau, Los Alamos County, New Mexico, by 

John H. Abrahams, Jr., James E. Weir, Jr., and William D. Purtymun____________________________________ 142 

340. Structural evolution of the Valles caldera, New Mexico, and its bearing on the emplacement of ring dikes, by R. L. 

Smith, R. A. Bailey, and C. S. Ross___________________________________________________________________ 145 

341. Hypothetical circulation of ground water around salt springs in western Oklahoma, Texas, and Kansas, by Porter 

E. Ward and A. R. Leonard-------------------------------------------------------------------------- 150 

342. Breccia at Sierra Madera, Texas, by R. E. Eggleton and E. M. Shoemaker___________________________________ 151 

343. John Day formation near Ashwood, north-central Oregon, by Dallas L. Peck__________________________________ 153 

344. Differentiated gabbroic sills and associated alkalic rocks in the central part of the Oregon Coast Range, Oregon, by 

P. D. Snavely, Jr., and H. C. Wagner_ ________________________________________________________________ · 156 

345. Relation between deformation, metamorphism, metasomatism, and intrusion along the northwest border zone of the 

Idaho batholith, Idaho, by Anna Hietanen____________________________________________________________ 161 

346. Deformation of the epicentral area, Hebgen Lake, Montana, earthquake of August 17, 1959-dual-basin concept, 

by Irving J. Witkind _______ - _- _------- _- ___ --------- _----- _________________ - ___________________ - _-- _ 165 

34 7. Deformation accompanying the Hebgen Lake, Montana, earthquake of August 17, 1959-single-basin concept, by 

W. Bradley Myers and Warren Hamilton______________________________________________________________ 168 

348. Stratigraphy of the Wilkins Peak member of the Green River formation, Firehole Basin quadrangle, Wyoming, by 

William C. Culbertson_______________________________________________________________________________ 170 

349. Chilson member of the Lakota formation in the Black Hills, South Dakota and Wyoming, by Edwin V. Post and 

Henry Bell Ill______________________________________________________________________________________ 173 

350. Artesian water in the Spiritwood buried valley complex, North Dakota, by C. J. Huxel, Jr_ _____ ,,,... ------------- 179 

351. A buried valley northwest of Manhattan, Kansas, by Henry V. Beck_______________________ ·-------------- 182 

352. Stratigraphy of lower and middle parts of the Pierre shale, northern Great Plains, by James R. h .1 and William A. 

Cobban----------------------------------------------------------------------------------------~--~ 185 

Geology and hydrology of Alaska and Hawaii 

353. •Analyses of gas and water from two mineral springs in the Copper River Basin, Alaska, by Donald R. Nichols and 

Lynn A. Yehle---~----------------------------------------------------------------------------------

354. Thrust faults in the southern Lisburne Hills, northwest Alaska, by Russell H. CampbelL __________ -------------

355. Physiographic proce.sses of sedge meadow pool formation on Latouche Island, Alaska, by Hansford T. Shacklette_ 

356. Regionally metamdrphosed metalliferous contact-metasomatic deposits near Nome, Alaska, by C. L. HummeL __ _ 

357. Multiple glaciation in the headwaters area of the Delta River, central Alaska, by Troy L. Pewe ______ - _---------

358. Recession of Portage Glacier, Alaska, by Ruth A. M. Schmidt_ _______________________________ --------------

359. Relation of discharge rate to dra wdown in wells in Oahu, Hawaii, by E. R. Lubke __________________ -----------

360. Preliminary gravity survey of Kilauea volcano, Hawaii, by H. L. Krivoy and J.P. Eaton _____________________ _ 

Extraterrestrial studies 

361. Thickness of the Procellarian system, Letronne region of the Moon, by C. H. MarshalL _______________ ---------

Geology and hydrology of other countries 

362. Revision of the geology of diamond districts in Bahia, Brazil, by Max G. White and Charles T. Pierson _________ _ 

363. Results of investigations for uranium in the Tucano basin, Bahia, Brazil, by D. D. Haynes and J. J,. Matzko_----

364. Thorium and rare earths in the Po~tos de Caldas zirconium district, Brazil, by Helmuth Wedow, Jr _____________ _ 

365. Vegetation-free zone on dry mangrove coasts, by F. R. Fosberg ____________________________________________ _ 

366. Polygonal features on bedrock, north Greenland, by William E. Davies __________________________ :--'----------

367. Cave deposits of phosphate rock in central Java, Indonesia, by Robert F. Johnson and Rab. Sukamto __________ _ 

191 

',.'194 

197 

198 

200 

202 

204 

205 

208 

211 

213 

214 

216 

218 

219 

.f 
CONTENTS \.. 

Geology and hydrology of foreign nations-Continued Page 

368. Pachuca mining district, Hidalgo, Mexico, by Arturo R. Geyne, Carl Fries, Jr., Kenneth Segerstrom, Robert F. 

Black, and Ivan F. Wilson _______ ------------------------------------~--_-- _____ ---- __________________ D-221 

369. Marine phosphorites of north-central Mexico, by Cleaves L. Rogers, Eugenio Tavera Amezcua, Jesus Ojeda Rivera, 

Zoltan de Cserna, and Roger van Vloten---------------------------------------------------------------- 222 

370. Deceleration of erosion at Pa.rfcutin, Mexico, by Kenneth Segerstrom ____________________ .____________________ 225 

371. The iron formation of the Surghar and western Salt Ranges, Mianwali district, West Pakistan, by Walter Danilchik_ 228 

372. Ground water in the Sabi Valley, Southern Rhodesia, by P. Eldon Dennis __ - ______________________ -·-__________ 231 

Paleontology, geomorphology, and plant ecology 

373. Geologic ranges of Cenozoic nonmarine diatoms, by Kenneth E. Lohman_____________________________________ 234 

37 4. Early Cretaceous (middle N eocomian) microfossils in south-central Alaska, by Harlan R. Bergquist______________ 236 

375. Late Permian ammonoids in the lnyo Range, California, and their significance, by Mackenzie Gordon, Jr., and 

Charles W. Merriam_--- - - - - - - - - - - - - - - - - - - - - - - - --- - - - - - - - - - - - - - - - - - - - - - - -- - - - - _ - _____ - - ____________ ~ _ 238 

376. A stratigraphically significant association of smaller Foraminifera from western Florida, by S. M. Herrick__________ 239 

377. Discharge of ground water by phreatophytes in the Waianae district, Oahu, Hawaii, by C. P. Zones--------------- 240 

378. Deflation in Buena Vista Valley, Pershing County, Nevada, by Robert E. Wallace_____________________________ 242 

379. Ostracodes and conodonts from the Getaway limestone member of the Cherry Canyon formation (Permian), Texas, 

by I. G. Sohn--------------------------------------------------------------------------------------- 244 

380. Physical characteristics of Upper Cambrian stromatolites in western Utah, by Richard K. Hose_________________ 245 

381. Pleistocene terraces on the Eastern Shore peninsula, Virginia, by Allen Sinnott and G. Chase Tibbitts, Jr_________ 248 

382. Stratigraphic significance of the Cretaceous fern 'fempskya in the western conterminous United States, by Charles 

B. Read and Sidney R. Ash- __ --------------------- -------------- _-------- __ -- _- ________________ . _ _ _ _ _ _ 250 

Geophysics 

383. Gravity low at Minto Flats, Alaska, by David F. Barnes--------------------------------------------------- 254 

384. Gravity survey near Tucson, Arizona, by Donald Plouff____________________________________________________ 258 

385. Electromagnetic studies in the Twin Buttes quadrangle, Arizona, by F. C. Frischknecht and E. B. Ekren_ _ _ _ _ _ _ _ 259 

386. Geophysical exploration of wells as an aid in location of salt-water leakage, Alameda Plain, California, by R. P. 

Moston and A. I. Johnson---------------------------------------------------_--------------- _____ --____ 262 

387. Aeromagnetic interpretation of zoned intrusions in northern Maine, by John W. Allingham _____________ ,_______ 265 

388. Aeromagnetic, aeroradioactivity, and gravity investigations of Piedmont rocks in the Rockville quadrangle, Mary- land, by Andrew Griscom and Donald L. Peterson_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 267 

389. Electrical properties of a part of the Portage Lake lava series, Houghton County, Michigan, by G. V. Keller______ 272 

390. Gravity anomalies, isostasy, and geologic structure in Clark County, Nevada, by Martin F. Kane and J. E. Carlson__ 274 

391. Isostatic compensation in the Sangre de Cristo Mountains, New Mexico, by Gordon E. Andreasen and Martin F. 

Kane--------------------------~------------------------------------------------------------------- 277 

392. The Rio Grande trough near Albuquerque, New Mexico, by H. R. Joesting, J. E. Case, and L. E. CordelL_______ 282 

393. Precambrian structures in the Blanding basin and Monument upwarp, southeast Utah, by J. E. Case and H. R. 

Joesting--------------------------------------------------------~----------------------------------- 287 

394. Use of geophysical data to interpret geology in Precambrian rocks of central Wisconsin, by John W. Allingham and 

RobertO. Bates-------------------------------~----------------------------~----------------------- 292 

:.,_ 395. Some observations of the eeismic-electric effect, by C. J. Zablocki and G. V. Keller____________________________ 296 

396. The significance of a group of aeromagnetic profiles off the eastern coast of North America, by Elizabeth R. King, Isidore Zietz, and William J. Dempsey ______________________ ~_________________________________________ 299 

Mineralogy, geochemistry, and petrology 

397. Composition of the iron-formation of Devonian age in the Christmas quadrangle, Arizona, by Ronald Willden____ 304 

398. Chemical analyses of brines and crude oil, Cymric field, Kern County, California, by E. H. Bailey, P. D. Snavely, 

Jr., and D. E. White________________________________________________________________________________ 306 

399. Sphene in granitic gneisses of southeastern Connecticut, by Richard Goldsmith, George L. Snyder, and Nancy M. 

Conklin--~----------------------------------------------------------------------------------------- 310 

400. Mineralogy of micaceous laminae in sandstones of Paleozoic age in Florida, by Dorothy CarrolL________________ 311 

401. Geochemical anomnlies in the upper plnte of the Roberts thrust near Cortez, Nevada, by R. L. Erickson, Harold 

Mnsursky, A. P. Mnrranzino, and Uteana Oda__________________________________________________________ 316 

402. Rndin.tion damnge and isotopic disequilibria in some uranium-bearing asphaltite nodules in back-reef dolomites, 

Cnrlsbad, New Mexico, by Arthur P. Pierce and John N. Rosholt, Jr______________________________________ 320 

403. Regular interlnyered chlorite-vermiculite in evaporite of the Salado formation, New Mexico, by Robert 0. Fournier_ 323 

404. Wenthering of peridotite, southwest Oregon, by Preston E. Hotz_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 327 

,J 405. Geochemicnl surveying for gold veins in the Atlantic district, Wyoming, by Richard W. Bayley and Willard W. 

Janes---------------------------------------------------------------------------------------------- 332 

406. Geographic distribution of mnjor constituents in strenm waters of the western conterminous United Stntes, by C. E. 

Roberson__________________________________________________________________________________________ 334 

407. Interaction of nnhydrite with solutions of strontium and cesium, by Irving Mny, Marian Schnepfe, and Charles R. 

Nneser--------------------------------------------------------------------------------------------- 336 

408. SoTQ,e alteration renctions in the system N8.:!0-Ab0rSiOrH20, by J. J. Hemley, Chnrles Meyer, and D. H. Richter._ 338 
VIII CONTENTS 

Mineralogy, geochemistry, and petrology,.-Continued Page 

409. A proposal for clarifying the use of plutonic calc-alkalic rock names, by Anna Hietanen ________ -- ___ ----------- D-340 

410. Origin of mottled structure in bedded calcium sulfate, by C. F. Withington ___________ -- ____ ------------------ 342 

411. Chemical basis of minor-element associations in coal and other carbonaceous sediments, by Peter Zubovic, Taisia 

Stadnichenko, and Nola B. Sheffey ___________________________________________________ ----------------- 345 

412. Some mechanisms for cooling hydrothermal fluids, by Paul B. Barton, Jr., and Priestley Toulmin 3d __ ---------- 348 

413. Some physical properties of bikitaite and its dehydration and decomposition products, by W. C. Phinney and D. B. 353 

Stewart ___________________________________________________________________________________________ _ 

414. Ground-water sources containing high concentrations of radium, by Robert C. Scott and Franklin B. Barker----- 357 

415. Chemical behavior of bicarbonate and sulfate complexes of manganese, by John D. Hem_--_-----:.------------- 360 

416. Overvoltage characteristics of a pyrite crystal, by Lennart A. Anderson ____________ -.---_--------------------- 362 

Geology and hydrology applied to engineering and public health 

417 .. Shatter cones formed by high speed impact in dolomite, by E. M. Shoemaker, D. E. Gault, and R. V. Lugn_----- 365 

418. Geologic results of November 1960 Project Chariot high-explosive_cratering experiment, Cape Thompson, Alaska, 

by Reuben Kachadoorian_____________________________________________________________________________ 368 

419. Engineering geology problems in the Yukon-Koyukuk lowland, Alaska., by Florence Robinson Weber and Troy 

L. P6w6_ ------------------------------------------------------------------------------------------ 371 

420. Hydrology of radioactive-waste disposal at the Idaho Chemical Processing Plant, National Reactor Testing Station, 

Idaho, by Paul H. Jones __________________________________________________________________ ------------ 374 

421. Disposal of uranium-mill effluent near Grants, New Mexico, by S. w: West___________________________________ 376 

422. Some uses of the sodium-adsorption-ratio diagram; by D. J. Cederstrom _______________ - __ -------------------- 379 

Exploration and mapping techniques 

423. Techniques for mapping of hydrochemical facies, by William Back ______________ ----------------------------- 424. Optical current meter, by Winchell Smith ________________________________________________________________ _ 

425. The effect of finite boundaries on measurement of gold-198 with a scintillation detector, by Bernard J. Frederick 

and Richard.G. GodfreY--------------------------~---------------------------------------------------

426. The magnifying single-prism stereoscope, virtually a new field instrument, by T. P. Thayer ____________________ _ 

Analytical and petrographic methods 

427. Trace element sensitivities, by Frank S. Grimaldi and Armin W. Helz __________ ------------------------------

428. Use of releasing agents in the flame photometric determination of magnesium and barium, by Joseph I. Dinnin __ _ 

429. Flame photometric determination of strontium with the use of releasing agents, by Joseph I. Dinnin ____________ _ 

430. ·Chemical aid for distinguishing chromite, ilmenite, and magnetite, by Joseph I. Dinnin and E. G. Williams------

431. Completeness of precipitation of selenium as the element, by Irving May and Frank Cuttitta_------------------

432. Evaluation of hydrologic tracers, by L. L. Thatcher _______________________________________________________ _ 

433. Gravimetric determination of silica in chromite and chrome ore, by Joseph I. Dinnin _______ --------------------

434. Comparison of drainage data obtained by the centrifuge and column drainage methods, by R. C. PrilL.. _________ _ 

435. Removal of manganese from solutions prior to determination of calcium and magnesium, by Lee C. Peck and Vertie 

C. Smith---------~---------------------------------------------------------------------------------

Index 

Subject---------------------------------------------------------------------------------------------------

Author----------------------------------------------------------------------------------------------------

Finding list of article page numbers ________________________________ ------------------------------------------

380 

383 

:385 

386 

388 

391 

392 

394 

394 

396 

397 

399 

401 

403 

407 

408 

~-
\... 

.J., 

GEOLOGICAL SURVEY RESEARCH 1961 

SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 

GEOLOGY OF METALLIFEROUS DEPOSITS 

293. POTASSIC FELDSPATHIZATION AND THORIUM DEPOSITION IN THE WET MOUNTAINS, COLORADO 

By GEORGE PHAIR and FRANCES G. FrsHER, Washington, D.C. 

Thorium, a.n eletnent 2.4 times" more abm1dant than 

uranium in the gra.nitic rocks of the earth's crust, is 

rttre ttS a hypogene constituent in hydrothermal veins, 

and the few· hydrothermal deposits of thorimn so far 

discovei·ed are obviously the result of special processes. 

Similarities in the settings of the three largest hydrothernla.l districts-the '\T et Mountains a.nd Powderhorn 

1Lre~1 in Colorado and the Lemhi Pass a.rea in Idahoprovide clues as to what these processes may be. Each 

district lies in deeply reddened (hema.titized) fractured 

siliceous PremL.mbrian rocks within a few miles of 

Tertiary volcanic rocks, which are presumed to have 

formerly capped the thorium-bearing rocks. 

In this paper ~" working hypothesis is presented relating thoriun1 deposition in the 'Vet Mounbtins to potassic feldspa,thiza.tion of granite a.long weathered, 

oxidized fractures beneath an impervious cap of volcanic rocks. A substantial body of chemica.] and minernJogicaJ :information indicates that the potassic feldspathization resttlted from reaction of the granite with 

aqueous solutions of moderate temperature but relatively high pH. The role played by the volcanic cap 

n1ust be clarified through further field work. 

The work of Christman, I-Ieyman, Dellwig, and Gott 

( 1953), of Chr:istm1tn, Brock, Pearson, and Singewald 

( 1960), and of Singew~tld and Brock (oral commmlication, 1959) has shown that the so-called veins in the 

Wet Mounta.ins are sporadically metallized linear shear 

tLnd breccia zones as much ~ts 5 miles long. · The composition of the ore changes n.long strike from sphalerite 

tLnd gn.lemt in carbomtte-barite-quartz matrix, to barite 

aggregates with ot.· without quartz-carbonate gangue, to 

red I<:-feldspn.r masses, some of which enclose the largest 

ttnd highest gra.de thorium deposits. Thorium occurs 

principally as tho rite and (or) thorogummite in disseminations, stringers, blebs, shoots, and pods. It also 

occurs, in at least one group of prospects, as a new mineral: a hydrated calcium thorium phosphate. 

A working hypothesis for the origin of the thorium 

deposits, based on 3 months' field work and laboratory 

studies, is outlined in the following paragraphs. 

1. Although the breccia zones cut a wide variety of 

igneous and mebtmorphic rocks, large high-grade 

thorium deposits are developed only in granite. 

2. Such granite has undergone intensive and extensive 

feldspathization, resulting in vuggy aggregates of 

course- to fine-grained red potassic feldspar containing less than 4 percent Ab and having the optics of 

low temperatlu·e microcline .. Terminated !{-feldspar 

crystals commonly project c01nb-fashion into open 

spaces, suggesting formation at no great depth. 

3. The feldspathized z01'les are strongly hematitized. 

Early hematite impregnates coarse "relict" microcline and commonly the cores, but rarely the rims, 

of smaller "recrystallized" microcline laths and gives 

rise to the typical "red rock" of the miners. 

4. During potassic feldspathization of the gr~tnite, 

large quantities of Si02, l\1:g0, CaO, Na20 and BaO 

were dissolved into the altering solutions and incorporated into the principal gangue minerals ( qmtrtz, 

barite, dolomite, and calcite) of fissure fillings. N a20 

·commonly migrated farther into the wall rocks to 

form replacement bodies of sodic amphibole and 

pyroxene. 

5. Elements in which the feldspnthized aggregates are 

enriched (Fe+3 , AI, Th, Y, and locally N d, Ce, La, Be, 

Nb) are those norm~tlly concentrated in granite and 

syenite during magmatic differentiation. These enD-1 
D-2 GEOLOGICAL SURVEY RESEARCH 19 61 

riched elements belong to Goldschmidt's (1937.) hydrolyzate group, having limited solubilities in alkalic 

solutions, and are thus predisposed to form residual 

concentrations. Because they could not be accommodated in the growing feldspar crystals, they were 

expelled into the adjacent spongy matrix to form an 

enriched protore. 

6. Because part of the feldspathization involved a 

simple replacement of K+ for Na+ in the feldspar 

lattice, with the associated Al+3 remaining behind, 

the altering solutions developed a considerable excess 

of N ~0 over tha"t which could react with Al20a to 

form albite; in short they took on the compositional 

peculiarities prerequisite to form sodic amphiboles 

and pyroxenes (Ernst, 1958, p. 202). Aggregates of 

fibrous blue magnesio-riebeckite developed wherever 

such sodic solutions encountered a source of MgO 

(diabase dikes and metagabbro layers; and mafic minerals in the. granite along an outer sodic "front"). 

Elsewhere, presumably under drier conditions 

(Ernst, 1960, fig. 3a), jade green acmite was the end 

product of sodic replacement. 

7. Thorium minerals belong to a late stage in a complex 

paragenetic sequence, and are believed to represent 

a re-concentration from the enriched protore. Such 

short-range thorium transport as may have occurred 

is tentatively attributed to carbonate complexing in 

solutions of appropriate alkalinity. 

Remley ( 1959) studied the relative stability of the 

successive products of. potassic hydrothermal alteration 

(clay minerals, mica, K-feldspar) in solutions of varying K+jH+ content at temperatures ranging from 200°0 

to 500°0 using a closed bomb technique.· He found 

that K-feldspar was the stable phase not only at higher 

temoeratures but also at moderate temperatures provided only that the pH is maintained ::sufficiently high. 

Later Remley (written communication, 1960) extended 

his experimental results to include sodic compositions; 

the preliminary indications are that K-feldspar, but rwt 

albite, is stable over an intermediate range of pH. 

Lacking information as to the K+ and Na+ content of 

the feldspathizing solutions in the Wet ~fountains, 

quantitative limits cannot be placed upon this intermediate pH range. However, the relative stability relationships developed in the laboratory appear to be 

borne out in a rather striking way in the field. . More 

recently, Morey and Fournier (1961) qualitatively confirmed Remley's results when they succeeded in leaching the exsolved albite from coarse perthite leaving the 

K-feldspar behind. This was accomplished by purriping water at a pressure of 3,000 pounds per square inch 

and a temperature of 300°0 through an open system 

containing the feldspar. 

From the evidence here summarized the origin of the 

thorium deposits in the Wet Mountains is reconstructed 

as follows: 

The early-formed breccia zones served as conduits 

for ground waters and became deeply oxidized in their 

uppermost portions prior to the onset of vulcanism. 

Once these conduits were capped by impervious volcanic rock, the "trapped" groundwaters heated by the 

regional rise in the. geotherms lay in contact w .ith partly 

weathered silicate rocks for an appreciable length of 

time and acquired a relatively high pH. The high pH 

in turn set in motion the process of potassic feldspathization, and secretion of· thorium and formation of the 

enriched protore resulted from this process. 

To n,n unknown extent the alkaline waters may have 

been augmented by (a) surface waters which took on 

a h.igh pH as they seeped downward through the partly 

glassy volcanic cover, and (h) hydrothermal solutions, 

presumably of higher temperature but lower pH, coming from below. Scattered lead-zinc deposits are inferred to have been formed from hydrothermal solutions 

under more strongly reducing conditions and at greater 

depth than the thorium ores, but as part of a more or 

less continuous process. Such acid, reducing soluti9ns 

rising to higher zones, would become "buffered" at a 

higher pH by the ubiquitous iron hydroxides there concentrated and eventually would become indistinguishable from the "trapped" liquid. 

REFERENCES 

Christman, R. A., Brock, M. R., Pearson, !t· C., and Singewald, 

Q. D., 1960, Geology and thorium deposits of the Wet 

Mountains, Colorado; a progress report: U.S. Geol. Survey 

. Bull. 1072-H, p. 491-535. 

Christman, R. A., Heyman, A. M., Dellwig, L. F., and Gott, 

G. B., 1953, Thorium investigations, 195o-1952, Wet Mountains, Colorado: U.S. Geol. Survey Circ. 290. 

Ernst, W. G., 1958, Alkali amphiboles: Carnegie Inst. Yearbook 

1957-1958, p. 199-204. 

--1960, The stability relations of magnesio-riebeckite: 

Geochim. et Cosmochim. Acta, v. 19, p.10-40. 

Goldschmidt, V. M., 1937, The principles of distribution of 

chemical elements in minerals and rocks: Cbem. Soc. 

[London] Jour., p. 655-673. 

Hemley, J. J., 1959, Some mineralogical equilibria in the system K20-AbOa-SiOr-H20: Am. Jour. Sci., v. 257, p. 241-270. 

Morey, G. W., and Fournier, R. 0., 1961, The decomposition of 

microcline, albite and nephelinE> in hot water: Am. Mineralogist, v. 46, p. 688--699 

;)" 
SHORT PAPERS IN THE GEOLOGrC AND HYDROLOGIC SCIENCES, ARTICLES 2 9 3-4 3 5 D-3 

294. STRUCTURAL FRAMEWORK OF THE ILLINOIS-KENTUCKY MINING DISTRICT AND ITS RELATION TO 

MINERAL DEPOSITS 

By A. V. HEYL, Jn., and M. R. BROCK, Beltsville, Md. 

The Illinois-l(entucky mining district is centered in 

the most complexly faulted area in the central craton 

of the United States. Structural studies suggest that 

the mineral district lies within a collapsed, blockfn.ulted, sliced, and partly rotated dmnaJ anticline that 

is located at and near the intersections of several major 

fn.ult lineaments. 

REGIONAL FAULT LINEAMENTS 

Six major fa.ult lineaments can be recognized in the 

region (fig. 294.1). (1) The New Madrid fault zone 

extends from near Vincennes, Ind., southwestward 

DOME 

__ ~S9~R.!_ __ 

ARKANSAS 

goo 

ILLINOIS BASIN /"f 

through and beyond New Madrid, Mo. (2) The Rough 

Creek-Shawneetown fault zone is traceable from the 

collapsed Jessamine dome of central l(entucky westward to the New Madrid fault zone, where it curves 

around the northwest end of the domal anticline and 

joins the west side of the New Madrid fault zone. 

( 3) The Ste. Genevieve fault zone begins south of St. 

Louis and trends southeastward into northernmost 

Tennessee. ( 4) The Cottage Grove fault is traceable 

across southern Illinois to the Mississippi River, where 

it may end against the Ste. Genevieve system. Faults 

of similar westward trend are traceable. through the 

WELLS CREEK 

EBDISTURBANCE 

25 50 75 

EXPLANAT ON 

Base ~ of Cretaceous rocks 

I I Cambrian through Mississippian rocks 

Precambrian 

Gr~ rocks 

--%-1--- Fault 

Showing dip and direction of 

displacement where known; 

dashed where inferred or concealed 

G3 

Intensely disturbed localized uplift 

.......... !-.......... 

Anticline 

........... r ......... Monocline 

Area ~ of Illinois-Kentucky 

district 

FIGURE 294.1.-Major structurnl features near the Illinois-Kentucky mining district. Geology compiled from mariy published · . 

sources by A. V. Heyl, Jr., J. J. Jolly, C. E. Wells, and M. R. Brock, 1960. 
D-4 GEOLOGICAL SURVEY RESEARCH 1 9 61 

southeast Missouri lead district to the Crooked Creek 

disturbance. ( 5) The zone of westward-trending 

faults along the south boundary of the western Kentucky coal basin joins the New Madrid fault zone in 

the southern part of the mining district. ( 6) Many 

vertical faults with a northwest trend (fig. 294.2) lie' 

along the axis of the collapsed domal anticline of the 

Illinois-Kentucky district and are traceable beyond it 

into the southern par:t of the Illinois basin. The individual fractures are cut and displaced by faults of 

the other systems. Many fractures are filled with 

mafic dikes. The mafic dikes suggest that these faults 

are deep-seated tensional fractures that formed during 

the development of the domal anticline. 

The north end of the\ Mississippi River embayment 

of the Coastal Plain and major parts of the channels 

of the Mississippi, Ohio, and Wabash Rivers in this 

region are very probably partly controlled by longcontinuing movements along the New Madrid and Ste. 

Genevieve fault systems. The largest of these two 

fault lineaments is the New Madrid fault zone, which 

has broken the rocks in the mining district into many 

narrow fault blocks and wedges that have a northeastward elongation. Woollard (1958, p. 1144) suggests that this fault zone is the southwestern part of a 

major structural break in the craton that extends northeastward beneath the sedimentary rocks into the St. 

Lawrence Valley as one of the great lineaments of 

North America. 

The New Madrid zone, the Ste. Genevieve fault zone, 

and the curved west end of the Rough Creek-Shawneetown fault zone are tectonically active today. The 

New Madrid fault zone is one of the most a·ctive seismic 

areas in the country at the present time, including the 

wide part of the zone crossing the Illinois-l{entucky 

district; more than 25 earthquakes have been recorded 

along the zone since 1937. Several of the most violent 

earthquakes of historic time were in the New Madrid 

series of 1811 to 1813 (Fuller, 1912). 

STRUCTURES NEAR AND IN THE DISTRICT 

The Illinois-l(entucky mining district lies within the 

northern part of a collapsed north-northwest trending 

domal anticline. The north end of the fold terminates 

against the arcuate west end of ·the Rough CreekShawneetown fault, which in this area is a high-angle 

thrust fault that has over 3,000 feet of vertical displacement (fig. 294.2). A branch fault, probably of 

the same attitude, extends southeastward from the main 

fault at least as far as Saline Mines, Ill. 

The main Rough Creek-Shawneetown fault system 

is a zone of shearing that shows evidence of being a 

wrench-fault system combined with a lesser high-angle 

thrust component of movement along steep, southwarddipping fault planes. The principal component of 

movement was strike slip that probably moved the 

north wall westward. The New Madrid fault zone apparently acted as shear-relief fractures for the Rough 

Creek-Shawneetown zone. The fault zone along the 

south boundary of the western l{entucky basin shows 

vertical and lateral displacements similar to the Rough 

Creek-Shawneetown zone. · 

The Cottage Grove fault is probably a weaker vertical wrench fault accompanied by scissors-type vertical 

displacements (Clark and Royds, 1948, p. 1748), as 

shown by the arrangement of the abundant subsidiary 

northwest-trending faults along it. The patterns of 

these subsidiary faults suggest that the main component of movement was strike slip, and that the rocks 

on the north side of the Cottage Grove fault moved 

eastward in relation to those south of the fault. This is 

the reverse of movement along the Rough Creek-Shawneetown fault.· The relative alinements of the Cottage 

Grove and Rough Creek-Shawneetown fault systems 

suggest that the Cottage Grove fault may be simply a .. 

west-trending branch of the Rough Creek-Shawneetown fault. 

HICKS DOME 

The faulted anticline within the mining district is 

dominated by Hicks dome, a circular structure that has 

about 4,000 feet of vertical uplift and a diameter of 

about 9 miles. The dome contains a cluster of mineralized explosion breccias in the Devonian rocks in its 

center and several other explosion breccias on its flanks. 

Near the periphery of the dome are clusters of both 

radial and concentric ring faults (Weller, Grogan, and 

Tippie, 1952, pl. 4; Stonehouse and Wilson, 1955). 

Many of these fractures contain veins that have been 

mined for fluorite and zinc. The changes in the pattern of the northeast-trending faults in the dome area 

suggest that faulting is younger than doming (fig. 

294. 2). 

Eight altered dikes of peridotite having alkaline 

affinities lie within the dome. An altered northeasttrending dike just east of the center ·is radioactive and 

enriched in rare earths, ba.rium, beryllium, niobium, 

gallium, and scandium similar to the fluorite-thoriumrare-earth breccias in the center of the dome. The 

magnetite of the dike is reported to be abnormally rich 

in zinc. Other dikes in the dome strike northwestward-parallel to all dikes elsewhere in the area and 

to the axis of the domal anticline. 

Some of the central breccias have been drilled 

(Brown, Emery, and Meyer, 1954) and trenched, and 

one radioactive breccia, that of the Rose mine, has been 

mined for fluorite. The deepest hole, the Hamp hole, 

was drilled to a depth of 2,944 feet and ended in intensely brecciated Ordovician rocks. The last 1,600 

.\. 
(-

SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 2 9 3-4 3 5 

0 

I 5 MILES I 

EXPLANATION 

Cretaceous and Tertiary 

Coastal Plain sediments 

• Mafic 

rocks alkaline 

cut in Explosion * drill holes 

Cretaceous(?) intrusive rocks 

Pennsylvanian rocks 

D 

breccias 

Devonian and Mississippian rocks 

Contact 

Dashed where inferred 

~ u . D 

Faults and fault zones 

U, upthrown side; D, downthrown side; 

arrows show probable relative movement 

•••• 

High-angle thrust fault; 

Teeth on overriding block 

--t----+ 

Anticline 

Showing direction of plunge 

-t----+ 

Syncline Showing direction of plunge 

'X' 

Fluorite, zinc, barite, and lead 

mines and prospects in veins along faults 

':::: ::: 

D-5 

1i'rouul~ 294.2.-Structure, mineral deposits, igneous rocks, and explosion breccias of the Illinois-Kentucky mmmg district. 

Geology compiled from 'Veller and Sutton, 1951; WeHler, Grogan, and Tippie, 1952; Clegg and Bradbury, 1956; Stonehouse and Wilson, 1955; and R. D. Trace, unpublished data, 1960. 
D-6 GEOLOGfCAL SURVEY RESEARCH 19 61 

feet penetrated strongly mineralized· breccia containing 

a matrix of 2 to 10 percent fluorite, much ba.rite, quartz, 

calcite, and a little pyrite, sphalerite, galena, biotite, and 

apatite. Thorium, rare earths, beryllium, zirconium, 

and niobium are intimately associated with the fluorite 

and barite and increase in amount with these minerals. 

The mineralogy of the shallow drilling and trenches 

was studied by Trace ( 1960), who identified an unusual 

yttrium-thorium monazite and florencite. The lead- · 

alpha age of this monazite is 90 to 100 million years, or 

middle Cretaceous ( T. W. Stern, oral communication, 

1960). 

The monazite is relatively unfractionated and is of 

the deep-seated type that is most likely to have been 

deposited originally at great depth in the earth's crust 

(W. C. Overstreet, oral communication, 1960), thus 

strengthening the suggestion by Brown, Emery, and 

Meyer (1954) that the breccias are mineralized diatremes and Hicks dome is a cryptovolcanic structure. 

The preSence of similar elements in both the mineralized 

breccias and the nearby dike, and also the abundance of 

fluorspar in the breccias, suggest a genetic relation between the two and to the rest of the fluorspar-zinc district. Fluorine, gallium, niobium, and barium are 

typical of igneous rocks of the alkaline series and are 

characteristic of mineral deposits closely associated with 

such rocks. 

ORIGIN. OF THJE DOMAL ANTICLINE 

The axis of the domal anticline from an apex at Hicks 

·aome plunges gently southeastward into northern Kentucky, where it is apparently displaced southwestward 

by faulting (fig. 294.2), and extends south through 

western Kentucky as the Kuttawa arch; the fold flattens and dies out south of Princeton, Ky. 

Unlike other domal uplifts of the region, such as the 

Ozark dome, the anticline formed during a relatively 

short period in post-Pennsylvanian time, probably,middle Cretaceous, because the Pennsylvanian and older· 

rocks are unthinned over the anticline. This domal 

folding probably was the result of the intrusion of a 

magma deep within the Precambrian basement at the 

intersection of several basement fault lineaments. The 

body was large, as is shown by the widespread extent 

of. the satellitic dikes and explosion breccias in the 

area. The first 'tension fractures to open during uplifting were those parallel to anticlinal axes, as proposed by Weller and others ( 1927). The mafic dikes 

that occupy many of t;hese are thought to be only 

slightly younger than the fractures. A gaseous explosion took place on the apex of the structure to form 

the smaller dome (Hicks dome) and its diatremes. Part 

of its gas and steam may have formed from the connate waters and petroleum in the heated Paleozoic rocks · 

overlying the magma. Subsequent cooling and shrinkage of the igneous rocks partly lowered the anticline. 

This action was combined with a compressive forcecouple acting along the Rough Creek-Shawneetown 

fault zone, which compressed and rotated the north 

end of the fold in a counter-clockwise direction to develop the numerous northeast-trending fault blocks. 

Mineralized, heated solutions moved upward along the 

previously formed faults and breccias and selectively 

deposited the minerals. The Mississippi River embayrp.ent was formed in Late Cretaceous time by downwarping of the block south of the intersection of the 

New Madrid fault zone and the Ste. Genevieve fault 

zone. 

REFERENCES 

Brown, J. S., Emery, J. A., and Meyer, P. A., Jr., 1954, Explosion pipe in test well on Hicks Dome, Hardin County, 

Illinois: Econ. Geology, v. 49, no. 8, p. 891-902. 

Clark, S. K., and Royds, J. S., 1948, Structural trends and 

fault systems in Eastern Interior Basin: Am. Assoc. Petro-

,leum Geologists Bull., v. 32, no. 9, p. 1728-1749. 

Clegg, K. E., and Bradbury, J. C., 1956, Igneous intrusive rocks 

in Illinois and their economic ·significance : Illinois Geol. 

Survey Rept. Inv. 197, 19 p., 1 map. 

Fuller, M. L., 1912, The New Madrid earthquake: U.S. Geol. 

Survey Bull. 494. 

Stonehouse, H. B., and Wilson, G. M., 1955, Faults and other 

structures in southern Illinois : Illinois Geol. Survey Circ. 

195, 4 p., 1 map. 

Trace, R. D., 1960, Significance of unusual mineral occurrence 

at Hicks Dome, Hardin County, Illinois, in Short papers 

in the geological sciences: u.s: Geol. Survey Prof. Paper 

.400-B, p. B63-B64. 

Weller, J. M., Grogan, R. M., and Tippie, F. E., 1952, Geology 

of the fluorspar district of Illinois : Illinois Geol. Survey 

Bull. 76, 147 p. 

Weller, Stuart, and Sutton, A. H., 1951, Geologic map of the 

western Kentucky fluorspar district: U.S. Geol. Survey 

Mineral Inv. Field Studies Map MF-2. 

Weller, Stuart, and others, 1927, The geology of Hardin County, 

Illinois : Illinois Geol. Survey Bull. 41, 460 p. 

Woollard, G. P., 1958, Areas of tectonic activity in the United 

.States as indicated by earthquake epicenters: Am. Geophys. 

Union Trans., v. 39, no. 6, p.1135-1150. 
SHORT PAPERS IN THE GEOLOGrC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-7 

295. POSSIBLE RELATION BETWEEN HYDROGEN SULFIDE-BEARING HYDROCARBONS IN FAULT-LINE OIL 

FIELDS AND URANIUM DEPOSITS IN THE SOUTHEAST TEXAS COASTAL PLAIN 

By D. HoYE EARGLE and ALICE D. WEEKs, Austin, Tex., and Washington, D.C. 

Since 1954, when uranium was discovered in western 

l{arnes County, in the Coastal Plain of southeast 

Texas, exploration activities for oil and gas and for 

uranium have been intimately associated. The uranium deposits were accidentally discovered during an 

airborne survey being conducted for a private oil operator on the theory that oil is associated with anomalous 

radioactivity. The uranium deposits were found in 

an area where oil has been produced for several decades 

frmn traps in comparatively shallow Tertiary sandstone beds along faults (fig. 295.1). The beds have a 

gentle regional dip to the southeast. The faults trend 

northeastward, nearly parallel to the strike of the beds, 

and the oil accumulations generally are located. where 

the faults bend slightly, producing an arcuate pattern 

that is convex updip. The faults seem to be part of 

the Mexia fault system, described by A. W. Weeks 

(1945, p. 1734). The beds along the principal faults 

are upthrown to the southeast; faults with the opposite 

displacement lie northwest of some of the main faults. 

The faults are generally en echelon; individual faults 

may extend from 5 to 25 miles. Faulting apparently 

began early in Late Cretaceous time, and movement on 

some was intermittent until at least Miocene time (A. 

W. Weeks,1945,p. 1736). 

Most of the uranium deposits are slightly up dip 

from faults upthrown to the east (Fashing and Hobson faults) and within a grabenlike area between these 

faults nnd the Falls City fault a few miles to the west 

(fig. 295. 1). The host rocks in the deposits are the 

alternating nonmarine and shallow-marine tuffaceous 

rocks in the upper part of the Jackson group (late 

Eocene) ; these sediments were covered, until recent 

geologic time, by the nonmarine Catahoula tuff (Miocene(~)). Deposits in near-surface pits are mostly 

oxidized and consist of yellow uranium minerals in 

films on bedding planes and disseminated in the sandstone. A few small pockets of unoxidized ore are in 

dark-gray pyritic clay under the main ore-bearing 

sandstone and contain disseminated black ore minerals 

and minute concretionary grains of uraninite, indicating precipitation in a reducing environment. 

The deposition of ore may have been brought about 

by a channeling of ground water into the graben-like 

area where there was a suitable reducing environment 

for precipjtation of uranium (Eargle, 1958; Macl{allor 

·and Bunker, 1958). Alteration of the tuffaceous sediments by ground water may have produced heulandite 

and released alkalies, silica, and several trace elements 

including uranium (Weeks, Levin, and Bowen, 1958). 

The uranium was redistributed by the alkaline ground 

water and' locally precipitated; the reducing conditions 

were caused by decay of plant fragments or by hydrogen sulfide, which was derived from decaying organic 

matter in the host rocks or derived as seepage of hydrogen sulfide gas from the deeper Ed wards limestone. 

The amount of hydr.ogen sulfide seepage necessary to 

form the deposits would be very s~all compared to 

the amount available in the Edwards. The mechanism 

has been described for another uranium deposit at 

PaJangana salt dome, Texas (Weeks and Eargle, 1960). 

In 1958 a large high-pressure gas field was discovered along the Fashing fault only a few miles south-· 1 

west of the richer uranium deposits; the gas is prol 

duced from the Edwards limestone (Lower Cretaceous) 

and is rich in hydrogen sulfide and distillate. Several 

other discoveries of sulfur-rich petroleum near other 

uranium localities in the Karnes region have been made 

since 1958. In 1959 the Person oil field in northern 

Karnes County, producing sour gas from the Edwards 

limestone, was discovered in an area where a surface 

radioactivity anomaly and some uranium minerals have 

been found. The Person field is about 20 miles northeast of deposits being mined in western Karnes County. 

Although the fault that forms the oil trap in this field 

is not known to cut formations younger than Paleocene, other faults in this area may have provided access 

for hydrogen sulfide seepage into overlying rocks. 

Three additional, widely scattered oil wells have 

recently been drilled along this trend from the Edwards 

limestone, each one a few miles down the dip from 

uranium prospects. The Bright and Schiff 1 Kunkel 

well, drilled in 1960, is about 3Y2 miles south of Falls 

City, and is about 3 miles east of and down the dip from 

an uranium prospect near the San Antonio River. The 

Standard of Texas 1 Manka well, also drilled in 1960, 

about 4% miles southeast of Falls City, is less than 2 
D-8 

gg• 

29° 

GEOLOGICAL SURVEY RESEARCH 1 9 61 

WILSON 

+ & 

GONZALES 

I 

.jsuperior Oil Co 

1 Dubose 

I 

T ______ I _. 

I I DEWITT 

I i 

+ 

I 

I 

~ ++ ~$$ 

KARNES 

0 Karnes City 

Kenedy 0 

I + $!:;· I 

_l + ~~ 

- -~~~- -..-------- +:~ I 

o:~ ~ 0 Fashingl I •:"-.. I 

L!)~ ~ I LBEE ~~Edwards-Fashing 

~~ field I - ~~ ; I 

LIVE OAK 

0 5 10 MILES 

EXPLANATION 

Well or core hole having high radioactivity anomaly 

+ 

Uranium prospect 

Uranium mine 

u ---oOutcropping fault 

U, upthrown side; D, downthrown side 

u ..--0--

Buried fault cutting Eocene sands, 

projected to surface 

U, upth1·own side; D, downthrown side 

u .••. o· ... 

Buried fault cutting Lower Cretaceous 

limestone, projected to surface 

U. u,ptlwown s1:de; D, downth:rown side 

Oil field producing from Eocene sands 

Oil field producing from Lower Cretaceous limestonl' 

Gas field producing from Eocene sands 

Gas field producing from Lower Cretaceous limestone 

• 

New oil discovery, Lower Cretaceous limestone 

FIGURE 295.l.~Oil and gas fields and uranium occurrences in the. Karnes County area, southeastern 

Texas. 
J, 

\ 

'· 

SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-9 

miles down the dip from two uranium prospects and is 

near two subsurface radioactive anomalies, found at a 

depth of about 100 feet by the gamma-ray logging of 

two wells. The Superior Oil Co. 1 Dubose well in 

southern Gonzales County, drilled late in 1960, is down 

the dip from an uranium prospect. Between the 

ura.nium prospect and the well in Gonzales County are 

several wells producing radioactive waters; a sample 

of water from one of these wells contained 10,700 p.p.c/ 

liter of radon-222 and 106p.p.c/liter of radium-226 

(A. B. Tnnner, written communication, 1956). 

The presence of hydrogen sulfide-bearing oil and 

gas near the uranium occurrences suggests that hydrogeL sulfide from the oil and gas was the reducing agent 

that caused precipitation of the uranium. 

REFERENCES 

Eargle, D. H., 1958, Regional structure and lithology in relation 

to uranium deposits, Karnes County area, Texas [abs.]: 

Geol. Soc. America Bull., v. 69, no. 12, pt. 2, p, 1557. 

MacKallor, J. A., and Bunker, C. M., 1958, Ore controls in the 

Karnes County uranium area, Texas [abs.] : Geol. Soc. 

America Bull., v. 69, no. 12, pt. 2, p.1607. 

Weeks, A. D., Levin, Betsy, and Bowe·n, R. J., 1958, Zeolitic 

alteration of tuffaceous sediments and its relation to uranium deposits in the Karnes Coun'y area, Texas [abs.] : 

Geol. Soc. America Bull., v. 69, no. 12, pt. 2, p. 1659~ 

Weeks, A. D., and Eargle, D. H., 1960, Uranium at Palangana 

salt dome, Duval County, Texas, in Short papers in the 

geological sciences: U.S. Geol. Survey Prof. Paper 400-B, 

p. B48-B52. 

'Veeks, A. ,V., 1945, Balcones, Luling, and Mexia fault zones in 

Texas: Am. Assoc. Petroleum Geologists Bull., v. 29, no. 12, 

p.1733-1737. 

296. RELATION OF FOLD STRUCfURES TO DISTRIBUTION OF LEAD AND ZINC MINERALIZATION IN THE 

BELMONT AND CALAMINE QUADRANGLES, LAFAYETTE COUNTY, WISCONSIN 

By WALTERS. WEST and HARRY KLEMIC, Washington, D.C. and Beltsville, Md. 

Worlc ·done in cooperation with the Wisconsin Geological and Nat1tral History Survey 

The Behnont and Calamine quadrangles, Lafayette 

County, "Tis., lie wholly within the Upper Mississippi 

VnJley zinc-lead district. Exposed in this area are 

Middle and Upper Ordovician rocks consisting of a few 

hundred feet of beds of carbonate rock and minor 

ltmounts of interbedded shale. These are underlain by 

ItS much as 340 feet of quartz sandstone, and, below this, 

by more tlut.n 1,000 feet of carbonate rocks, shale, and 

sandstone of Cambrian and Early Ordovician age 

(table 296.1). At ma,ny places in the Belmont and 

C1t.la,mine quadrangles, particularly in the.latter, dolomite is prevalent in the exposed carbonat~ rock 

sequen9e. 

The Ordovician strata have a regional dip of less 

than 1° SSW except where they have been folded. The 

nxes o~ major folds nnd locations of domes and basins 

in the two quadrangles, as determined by structure contour maps of the top of the Platteville formation, are 

shown on figure 296.1. Most of the folds have amplitudes of only a few tens of feet; the greatest structural 

relief is about 190 feet on the top of the Platteville 

form.ation from the crest of the southernmost anticliiie 

in the Belmont quadrangle to the trough of the syncline 

in the southwestern part of. the quadra,ngle. 

604493 Q-61--2 

Shown on figure 296.1, also, are the locations of mines, 

prospect pits, and drill holes in'·which lead and zinc 

minerals have been found in significant amOtmts. 

Groups of dots indicate gen~~al a,reas where ore was 

mined. Trace amounts of lead or zinc· minerals were 

found at many localities not shown on the map, and 

some workings where lead was mined in e.:'trly days may 

have been obliterated an{ cannot be located. 

We offer 'the following explanation of how the ore 

bodies were. emplaced. We suggest that limestone beds 

in the Platteville and Decorah formations at one time 

were the uppermost limestone beds beneath an erosion 

surface on the Galen~ dolomite (Du Bois, 1945) or 

the Maquoketa shale (Brown and Whitlow, 1960), and 

that meteoric waters· moved through joints and fractures in the rocks, dissolving and thinning the limestone 

beds preferentially. Some compaction of residual material and slumping in the partly dissolved beds may 

have occurred late in this period. During a period of 

tectonism, possibly contemporaneous with the waning 

period of solution or perhaps distinctly la.ter, the solution-thinned beds and some adjoining beds were brecciated, sets of inclined fractures formed, and beds overlying the zones of solution-thinning sagged into the 
D-10 GEOLOGICAL SURVEY RESEARCH 19 61 

TABLE 296.1.-Stratigraphic section of rocks exposed in the Belmont and Calamine quadrangles, Wis. 

Series Formation Thickness Description (feet) 

Shale, gray or blue, and dolomite, gray; phosphatic nodules and deUpper Ordovician Maquoketa shale 40+ pauperate fossils in thin zone near base; occurs in the northwest 

corner of the Belmont quadrangle. 

Dolomite, buff to grayish-orange, and numerous ~nterbedded thin layers 

of nodular chert in lower half; limestone in the lower part of the 

220+ formation lo~ally in the ~est-central part of the Belmont quadrangle; 

zinc-lead deposits in fractures in the lower part of the formation and 

lead-zinc deposits along vertical crevices higher in the formation; 

underlies and crops out over large areas. 

Galena dolomite 

Dolomite and limestone, gray to buff or grayish orange; entirely 

Decorah 30-35 dolomitic at many places; underlies large areas; zinc-lead ores in 

inclined and horizontal fractures, and in solution-thinned and brecciated zones. 

Middle Ordovician 

Dolomite in lower part, buff to pale-gray; limestone or dolomite in 

middle part, light-gray; limestone or dolomite in upper part, pale 

Platteville 65.± purplish gray, aphanitic or fine-grained; entire formation is dolomite 

at many places; underlies large areas but outcrop area is small; 

zinc-lead ores in fractured, brecciated, and solution-thinned zones in 

upper part. 

St. Peter sandstone 

Quartz sandstone, white to yellowish, cross bedded friable; iron-oxide35+ . cemented layer near top; underlies large areas but exposed only in 

valleys. 

yoids. Still later, solutions carrying the ore elements 

entered the fractures, breccias, and solution-thinned 

zones and deposited the ore minerals. 

The solutions which deposited the ore minerals 

probably differed consi~erably from those responsible 

for the major thinning of the host rocks, as is indicated 

by the following facts : (a) Some ore-cemented breccias contain angular rock fragments that show only 

minor solution effects. (b) The footwall sides of 

heavily mineralized inclined fractures show relatively 

extensive thinning, whereas the hangingwall sides show 

relatively little. This suggests that the major parts 

of the solution preceded the inclined fractures, which 

formed prior to mineralization. (c) A thin film of 

iron sulfide, which generally coats the host rocks of 

the ore, probably inhibited reaction of the ore solutions 

with the carbonate rocks. 

Ore deposits in the dolomite of the Galena developed 

in somewhat similar stages as has been suggested by 

Bradbury (1959). Extensive solution of rock occurred 

along vertical joints and fractures in some beds. Interstitial calcite in beds of calcareous dolomite was dissolved preferentially, and cavernous and porous zones 

were produced. The remaining parts of the dolomite 

beds were sufficiently strong to prevent extensive collapsing within and above the porous and cavernous 

beds. Ore solutions later entered these zones and deposited the sulfides. 

If the proposed sequence of events leading to the 

emplacement of the ore deposits is correct, then ore 

bodies might be found in shallow surface synclines 

caused by the sagging beds over solution-thinned zones. 

It has been suggested that synclinal basins are favorable places in which ·to prospect for ore in the Upper 

Mississippi Valley district (Grant, 1906, p. 85 and 86; 

Heyl and others, 1959, p. 170-172). We suggest, however, that the widespread and possibly random distribution of mineralized sites with respect to the folds 

is an indication that in the Belmont and Calamine· 

quadrangles the tectonically folded structures are not 

useful guides to ore deposits, and that localization of 

ore deposits was not controlled by these folds. All 

sites of lead deposits in vertical crevices in the two 

quadrangles are places that were pervaded by solutions 

capable of dissolving limestone and by solutions carrying the ore eleme~ts. If the fracture systems provided 

access to the underlying Decorah and Platteville formations where they contained limestone beds, it is 

likely that solution thinning would have occurred in 

the limestone layers, and collapse features would have 
.I.. 

.. . 

SHORT PAPERS IN THE GEOLOGrC AND HYDROLOGIC SCIENCES1 ARTICLES 293-435 

.. 

D :0 ~--:\-- •. ~. 

B 

~ 

D 

· .. · \, _;.,-\- .--- -.~· \ ...._ _.,., .. · 

\ '-. ... ·• B~-

1 ~ ~ ~· ...•.. __ __, ·~ B 

I .. . . D ·~ 

/ :s~ ~~ .... · .· 

: 

~ .. 

EXPLANATION 

---- Anticline 

Showing bear~ng and plunge of axis. 

Dashed where: approximately located 

---- Syncline 

Showing bearing and plunge of axis. 

Dashed where approximately located 

Monocline 

D 

Dome 

Approximate top 

B 

Basin 

Approximate bottom 

Old mines, prospect pits, 

and other occurrences of 

lead or zinc minerals 

0 2 MILES 

B 

. . 

: . . . 

. · 

D-11 

FIGURE 296.1.-Map showing structural features and major occurrences or lead and zinc minerals in the Belmont and 

Calamine quadrangles, Wisconsin. 
D-12 GEOLOGICAL SURVEY RESEARCH 19 61 

formed in which ore deposits could have been deposited. 

Where the underlying rocks were dolomite, solution 

thinning would have been negligible. Where layers of 

rock bridge partly dissolved beds, ore deposits could 

exist with no structural expression at the surface. 

Such sites of mineralization may occur in the northcentral and south~central parts of the Calamine quadrangle. If the original solution thinning occurred 

prior to the major folding as is suggested here, there 

may be only a foituitious relation between the folds and 

the ore deposits, regardless of whether the ore minerals 

were deposited before, during, or after the folding. 

REFERENCES 

Bradbury, J. C., 1959, Crevice lead-zinc deposits of northwestern 

Illinois: Illinois Geol. Survey Rept. Inv. 2100. 

Brown, C: E., and Whitlow, J. W., 1960, Geology of the Dubuque 

South quadrangle: U.S. Geol. Survey Bull. 1123-A [1961]. 

DuBois, E. P., 1945, Subsurface relations of the Maquoketa and 

Trenton formations in Illinois : Illinois Geol. Survey Rept. 

Inv. 105. 

Grant, U. S., 1906, Report on the lead and zinc deposits of 

Wisconsin, with an atlas of detailed maps: Wisconsin Geol. 

and Nat. History Survey Bull. i4, Econ. ser. 9, p. 85 and '86. 

Heyl, A. V., Jr., Agnew, A. F., Lyons, E. J., and Behre, C. H., Jr., 

1959, The geology of the upper Mississippi Valley zinc-lead 

district: U.S. Geol. Survey Prof. Paper 309. 

HYDROLOGIC STUDIES 

297. RESERVOIR STORAGE FOR SHORT-PERIOD STREAMFLOW REGULATION 

By G. N. MESNIER, R. E. OLTMAN, and W. B. LANGBEIN, Washington, D.C. 

Several grap~s were prepared as part of studies for 

the Senate Select Committee ( 1960) for computation 

of the storage required to increase low flow of streams 

in major river basins. These may be of use or interest 

in the solution of other similar problems. The graphs, 

shown on. figures 297.1-297.3, present generalized sets 

.of curves expressing the relation between regulated 

flow and required storage. The ordinate is regulated 

flow expressed in ratio to the mean, the abscissa is the 

required storage capacity in days, and the parameter 

is the variability index. The variability index, as 

defined by Lane and Lei ( 1950), is the standard deviation of the common logarithms of the daily discharges. 

Storage capacity, reported in days, represents the volume in ratio to the mean flow of the river. Thus, a 

capacity of 20 days is a volume equal to a flow of 20 

days at the mean rate. 

Given the mean flow and the variability index characteristic of a region, an estimate may be made of the 

storage required to sustain flows of increasing 

magnitude. 

Figure 297.1, showing the maximum storage required, was prepared by mass-curve analysis (Linsley 

and Franzini, 1955, p. 138-140) of the monthly flows 

of 25 different streams in the conterminous United 

States. Storage required for draft rates of 20, 40, 60, 

and 80 percent of the mean was then determined by 

customary mass-curve techniques. The data for the 

several streams were then grouped in terms of their 

variability indices and averaged. Figure 297.1 therefore represents a rough estimate of the storage required 

for streamflow regulation during the most adverse or 

lowest sequences in a particular period of streamflow 

record. 

Figures 297.2 and 297.3 represent the amounts of 

storage required, assuming that the low flows are equal 

to the lowest flows that occur in 1 year in 20, and in 1 

year in 5. · These requirements are less stringent than 

the requirements assumed for figure 297.1 and therefore yield lower estimates for volumes of storage. 

Two principal factors control the amount of storage--

the first is variability, and the second is the sequential 

1.0 z: 

Gl~--------~ ~ 

::E 

·o 

..... 

0 0.5 i= 

~-' ,~~v·r~~~~;" ~ 

~ 

3: 

~ 

8 0.2 ..... 

5 

:I 

c.!' 

...... 

c.: 

0.1 

5 10 20 50 100 200 500 

DAYS STORAGE 

FIGURE 297.1.-Storage required for streamflow regulation 

during periods of low flow equal to the lowest flow of record. 

1\ 

<;;;. 
.. , 

,I. 

SHORT PAPERS IN THE GEOLOGTC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-13 

1.0 

~ ::::E 0.5 0 

.... 

0 

i= 

~ 

~ 

3:: 0.2 0 

;::: 

Q 

...., 

.... 

:5 

:::1 0.1 

ffi 

a: 

0.051 

~~~~~ -:// / /,~-Variability index 

10 20 so 100 

OAYS STORAGE 

FIGURE 297.2.-Storage required for streamflow regulation 

during periods of low flow equal to the low flow of 1 year 

in 20. 

order in which the flows occur. ·Variability is evaluated 

by the variability index, but because the index is based 

on the variability of daily flows it may not be representative of the variability among longer periods. The 

sequential order is largely controlled by the seasonal 

regimen; the greater the tendency for low flows to 

occur in a consecutive sequence, the greater the storage 

requirement. The sequential effects are evaluated implicitly in the graphs. 

In constructing the figures, widely varying results 

for different streams were averaged and smooth curves· 

constructed. Part of the differences represent inherent 

differences among the streams, and part is due to the 

behavior of each stream during the particular period 

of streamflow record. Different periods of record would 

not only indicate different amounts of storage reql:lired, 

but different values of the variability index as well. 

Figures 297.1-297.3 average out these components, and 

LOr-----------------------. 

z 

~ 

:::::e 

0 

.... 

0 

i= 

~ 

~ 

3:: 0.2 

~ 

8 

.... 

::5 

:::1 0.1 

ffi 

a: 

0.05 

1 10 20 50 100 

DAYS STORAGE 

FIGURE 297.3.-Storage required for streamflow regulation 

during periods of low flow equal to the low flow of 1 year in 5. 

are, therefore, averages of both place and time, a fact 

that restricts their usefulness. 

Although curves such as those shown may not be 

applied to any particular stream, or a particular period 

of years, they can be used in a general way to form 

estimates of storage needed for short-term regulation 

of stream·s. , 

The curves show that required storage increases 

greatly with increase in the variability index and with 

increase in the regulated flow. · 

REFERENCES 

Lane, E. W., and Lei, Kai, 1950, Streamflow variability: 

Am. Soc. Civil Engineers Trans., v. 115, p. 1084-1134. · 

Linsley, R. R., and Franzini, J. B., 1955, Elements of 

hydraulic engineering: New Yorl{, McGraw-Hill Book Co. 

Senate Select Committee, 1960, National water resources and 

problems: Committee Print No. 3, Select Comm. on Natl. 

Water Resources, U.S. Senate, 86th Con,g., 2nd Sess. 

298. RESERVOIR STORAGE-GENERAL SOLUTION OF A QUEUE MODEL 

By W. B. LANGBEIN, Washington, D.C. 

For1nal application of the theory of queues to the 

design or operation of reservoir storage usually leads 

to a set or system of simultaneous linear equations that 

must be solved for each specific case. However, a gen- . 

eral solution appears possible if certain approximations are made. In this example, a three-state 

approximate solution is described for the case when 

a uniform draft rate upon the reservoir is required. 

In the solution, it. is assumed or specified that : 

1. Random inflows during successive units of time are 

approximated by a trinomial probability distribution. The distribution supposes that the inflow 

in any interval of time has one of three values, 

B +A, B, and B-A. The value of B is the draft 
D-14 GEOLOGICAL SURVEY RESEARCH 19 61 

rate, and the value of A and of the probabilities 

associated with each of these quantities B +A, B, 

B-A, is such that their mean and standard deviations are equal to the mean ( Q) and standard deviation ( s) of the inflows as given. 

2. The reservoir capacity contains n integral units of 

volume, each equal to A. 

3. Reservoir contents at the beginning or end of any 

unit of time may be in one of the n+2 states, which 

are empty, between empty and A, bet:ween A and 

2A, ...... or full. 

4. Reservoir storage in a unit of time may (a) decrease 

one unit when inflow equals B-A, for which the 

probability. is q j (b) remain the same when inflow 

equals B, for which the probability is Tj or (c) 

increase one unit when inflow equals B+ A, for 

which the probability is p. 

5. The probability of changing more than one unit is 

neglected, so the alternatives above are the only 

possible ones. Hence, 

q+T+p=l.O. 

These probabilities are subject to the boundary conditions imposed by an empty reservoir when a decrease 

in contents is not possible, or by a· full reservoir when 

an increase in the contents is not possible. These conditions can be stated as fGllows: 

1. When empty at a given time, the probability that 

the reservoir will remain empty at end of next 

interval of time equals the probability of inflow 

less than the uniform rate of draft, B. The probability of this occurrence is q0 • 

2. When empty at a given time, the probability that 

at the end of the next interval of time the reservoir 

will be in the first storage range, between zero and 

A, is equal to the probability of inflow gFeater 

than B. The probability of this occurrence is Po· 

By definition 

3. When the reservoir is initially full, the probability 

that the reservoir will remain full at the end of 

the next interval of time is equal to the probability 

of an inflow greater than B. The probability of 

this occurrence is Po· 

4. When the reservoir is initially full, the probability 

that the reservoir will be in the storage range 

below the spillway at the end of the next interval 

of time is equal to the probability of inflow less 

than B. The probability of this inflow is q0• 

These statements can be expressed as a matrix, as 

follows: 

STATES AT BEGINNING OF INTERVALS 

Po Po-l P1-2 Pen-u-n Pn 

Po 9o 9 

(J) 

...J Po-l 

~ Po r 9 

ex: 

1.1.1 

1- P1-2 p r ~ 

~ 

0 P2-3 p z 

1.1.1 

1- - < Pcn-2>-Cn-1> 9 (J) 

1.1.1 

1-

< 

(J) 

1- Pcn-1)-n r 9o 

Pn p Po 

Subject to the condition that 

Po+ Po-l+ P1-2+. .P(n-1)-n+ Pn=l.O 

Note that the probabilities in each column total unity 

because these represent all possible alternatives. 

The solution of this set of simultaneous equations 

leads to the following results for the probabilities of the 

reservoir spilling and of being empty: 

where Pn is the probability that reservoir spills, Po is 

the probability that reservoir is empty, and, n is the 

reservoir capacity in ratio to A. 

The number of terms fu the denominator of the above 

fractions equals the number of storage states; that is, 

n+ 2. The value of P 0 is also equal to the probability 

of "failure"; that is, the probability that discharge from 

the reservoir will be less than B, the design rate of draft. 

The values of p, q, and A are defined by the following 

equations: 

p-q=y/A 

r=l-p-q 

y=(Q-B)/s 

'1 

.J 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-15 

The values of p0 and q0 are read from the given distribution of reservoir inflows. The value of Po is the probability of inflow greater than B and q0 the probability of 

inflow less than B. The sum of p0 and q0 equals unity. 

z 

0 

~ 

> w 

0 

0 

a: 

<l 

0 

~ If) 

0 

1-

0 

i= 

~ 

! 

Calculations have been made for probability of spilling (P,~) and of empty (Po) for various combinations 

of capacity and draft rates. The results are given nondimensional form on figure 298.1 for a normal and ran9 

7 

6 

5 

4 

.... 

1- 3 u 

<l 

~ 

<l 

u 

2 

PROBABILITY, IN PERCENT 

FIGURE 298.1.-Probabilities of reservoir being empty or spilling, 

normal distribution of infiows. 

dom distribution of inflows and on figure 298.2 for a 

logarithmic normal distribution of· inflows having a 

coefficient of skew equal to 1.0. 

The same curves can be applied to the case where the 

reservoir is operated so that discharge does not exceed 

some rate B. In this case, y= (B-Q)/s and the 

"empty" and "spill curves of figures 298.1 and 298.2 are 

to be interchanged. 

9 

6 

z 

,!;! 7 

1-

<l 

~ 0 

0 6 C!: 

<l 

0 

z 

<l 

1-

(/) 5 

0 

1-

~ 

.... 

1- 3 ;:; 

~ <l 

u 

2 

oL-----L---~-=~~~~~~~--~--~~----~ 

0.1 5 10 20 50 60 90 95 99 

PROBABILITY, IN PERCENT 

FIGURE 298.2.-Probabilities of reservoir being empty or spilling, 

logarithmic distribution of inflows, skewness=l.O. 

299. ORIGIN OF REGRESSIVE RIPPLES EXPLAINED IN TERMS OF FLUID-MECHANIC PROCESSES 

By ALAN V. JoPLING, Washington, D.C. 

Work done in cooperation with Harvard University 

As defined here, a regressive ripple suite refers to a 

sequence of asymmetric ripples oriented in the direction 

oppoSite to the general movement of current flow. Such 

ripples should be distinguished from the antidune ripples described by Shrock (1948) and others. Regressive ripples were recorded by me 1 during the course of 

1 Jopling, A. V., 1060, An experimental study on the mechanics of 

bedd,ing: Unpub. Ph. D. Thesis, Harvard Univ., 358 p. 

an experimental flume investigation on the mechaniC$ 

of bedding. The origin of this particular type of 

structure is related to flow separation (Rouse, 1946, 

p. 232-234) that occurs when a current expands over a 

sharp discontinuity (such as a delta front) in a channel 

floor. Flow separation generates a vortex system in 

the lee of the discontinuity. For a deltaic transition, 

a reverse circulation or backflow is directed toward and 
D-16 GEOLOGICAL SURVEY RESEARCH 19 61 

up the foreset slope, aud therefore any "normal" ripples 

developed as bottomset structures in response to reverse 

circulation are regressive only with respect to the general flow direction. 

So far as the writer is a ware, naturally occurring 

regressive ripples in the bottomset deposit of a crossbedded unit have not yet been recorded, although it 

seems probable that they exist. 

For subcritical transitions, and for those supercritical-subcritical transitions in which the Froude number· 

is not much in excess of one, as in most natural streams, 

the varied flow pattern resembles jet expansion over 

a finite discontinuity. The hydraulic phenomena in 

the immediate vicinity of the delta front are those of 

free-turbulence shear flow, with restrictions imposed by 

the boundary geometry .. The hydraulic geometry and 

zonal terminology adopted here for the flow transition 

are diagrammatically illustrated on figure 299.1. 

... Consideration is given only to a transition characterized by a relatively low concentration of suspended 

sediment. A high concentration results in a gravity 

underflow (turbidity current) that moves along the 

bottomset floor, and the flow pattern assumes an 

entirely different character. 

Based on a jet analogy, the zone of no diffusion (fig. 

299.1) may be simply regarded as a vestigial phase 

of the upstream flow regime extending for a limited 

distance beyond the lip of the delta. This zone is 

unaffected by the eddies of lateral mixing that are 

developed marginal to the expanding "jet," and its 

. velocity distribution is similar to that of the upstream 

flow (with a progressive, basal "truncation" in the 

downstream direction) . 

The region of mixing, on the other hand, is characterized by a rapidly altering distribution of velocity 

and by strong macro-turbulence activity. Hydraulic 

parameters such as the locus line of zero velocity and 

the line of no diffusion, can be designated onli in a 

nominal sense on account of the statistical nature of 

the mixing processes involved. 

The processes of fluid entrainment (resulting from 

flow expansion) and return flow (necessary to satisfy 

the continuity relationship) motivate a relatively stable 

eddy that gyrates in the toe sector of the delta. This 

is the eddy, already referred to, that is responsible for 

the development of regressive ripples. A series of 

measurements in a laboratory flume indicated that the 

maximum velocity of backflow (reverse circulation) 

ranged from about Ys to 1;3 that of the mean velocity 

of streamflow upstream from the delta front. The 

value depends upon the velocity of the flow, and upon 

the depth-ratio (ratio of depth at the lip to depth at 

the toe of the delta). For Reynolds numbers less than 

3 x 104 , and for a deltaic discontinuitY. with a 30-degree 

slope and a wide range of depth-ratios, most of the 

velocity-ratios lay between 1;5 and 11.t,. 

Theoretical considerations alone, based on a general 

knowledge of the hydraulic geometry of flow expansion, 

should suffice, therefore, to explain the occurrence of 

regressive ripples in a bottomset deposit. 

The experimental results from a number of deltabuilding runs demonstrate that 3 types of ripples may 

develop in the bottomset deposits of a crossbedded unit: 

(a) progressive ripples that migrate in the downstream 

direction, (b) regressive ripples that develop within 

the zone of reverse circulation, and (c) hummocky, 

nondirectional ripples (current marks) that represent 

a transitional phase between (a) and (b) . 

The progressive ripples are "normal" current ripples 

that are directed downstream beyond the zone of reverse circulation. There is nothing unusual about their 

occurrence. However, as the delta front and the zone 

of backflow advance, the progressive ripples are 

changed-either partly or fully-into regressive ripples. Hummocky, nondirectional ripples result if the 

transformation is incomplete. 

Length of zone of reverse circulation 

about 7± times thickness of delta 

Large scate 

eddies 

Zone of no diffusion of eddies 

of free-turbulence shear flow 

Velocity distribution 

FIGURE 299.1.-Schematic representation of zonal terminology for a flow transition over a delta front. 
!-

SHORT PAPERS IN THE GEOLOGrc· AND HY·DROLOGIC SCIENCES, ARTICLES 293-435 D-17 

The hummocky type of ripple characteristically 

forms near the diffuse termination of the zone of reverse circulation. '¥11ether :the transformation to 

regressive ripples is completed will depend on the velocity of the backflow, the intensity of turbulence in, 

the locale of the delta front, and the relative rates of 

foreset and bottomset deposition. Therefore, the ripples ·at the delta toe may be either regressive··· or 

hummocky. 

The question arises concerning the probability of the 

burial and preservation of regressive and hummocky 

ripples as integral bottomset structures underlying the 

deltaic foresets. Flume observations demonstrated 

that the essential ripple-geometry could be preserved 

in spite of the periodic impact of slumping foreset detritus. In several delta-building runs involving the 

deposition of angular crossbeds, the only observable 

effect caused by slump was a slight to moderate distor-

'tion or puckering of the bottomset ripples, and, for the 

tangential type of unit, the evidence indicated that the 

ripples could be completely preserved. 

The occurrence of regressive ripples in experimental 

models suggests that eventually they will be found in 

nature. The juxtaposition of regressively rippled bottomsets and deltaic foresets could conceivably pose a 

perplexing problem. in the interpretation of paleocurrent directions. If ripple orientation were used as a 

diagnostic index, the conventional interpretation of 

current direction would be 180 degrees in error. Furthermore, the preservation of hummocky ripples could 

also pose an enigmatic problem in field analysis. 

If regressive ripples were recognizable in a field occurrence of crossbedding, it should be possible to estimate the strength of the original current, on the 

assumption that the ratio of the velocity of backflow 

to that of the stream is roughly 1 :4. The minimum 

velocity for the initiation of ripples in sandy sediments 

generally lies smnewhere in the range 1f2 to 1 foot per 

second, and therefore the occurrence of regressive ripples in a crossbedded sandstone unit would suggest a 

stream velocity of not less than 2 feet per second. The 

structure, therefore, may serve as a subordinate criterion in studies of environmental interpretation. 

REFERENCES 

Rouse, Hunter, 1946, Elementary mechanics of fluids: New 

York, John Wiley and Sons, 376 p. 

Shrock, R. R., 1948, Sequence in layered rocks: New York, 

McGraw-Hill Book Co., 507 p. 

300. THE SIGNIFICANCE OF THE FALL VELOCITY AND EFFECTIVE FALL DIAMETER OF BED MATERIALS 

By WILLIAM L. HAUSHILn, DARYL B. SIMoNs, and EVERETT V. RICHARDSON, Fort Collins, Colo. 

Particle-size distribution of bed materials based 

upon the fall velociJty of the particles will vary with 

the characteristics of the fluid. Results of size analyses 

conducted in the visual-accumulation tube for a sample 

of the Elkhorn River, Nebr., sand in distilled water and 

in 1, 5, and 10 percent by weight bentonite in distilled 

water are shown on figure 300.1. The distribution in 

distilled water is in terms of fall diameters obtained 

directly frmn the standard fall velocity; fall diameter 

and standard fall velocity are defined in a report of 

the United States Inter-Agency Committee on Water 

Resources (1957). The distributions in the bentonitewater dispersions are described in terms of an effective 

fall diameter (effective size). The effective fall diameter of a particle for a given sedimentation medium and 

temperature is the diameter of a quartz sphere whose 

standard fall velocity equals the average terminal fall 

velocity of a particle when it falls alone in an infinite 

extent of the medium at the given temperature. 

The influence of effective size of particles on the mechanics of flow in alluvial channels was studied in 

flume experiments by changing tl_1e fall velocities of 

bed materials through variation of the sedi1nentation 

medium, and by using bed materials of different sizes 

and specific gravities. The sedimentation medium was 

changed by adding fine sediment (bentonite) to the 

flow, and by varying the temperature of clear water 

(Hubbell and Ali, Art. 301). Changes in the effective 

_sizes of pa-rticle were found to change the forms of bed 

roughness, resistance to flow, and sediment transport. 

For the fine-sediment study, the bed material used 

in the flumes was natural sand with mediJan fall diameters of 0.54 mm and 0.4 7 mm, and the fall ·velocity and 

effective fall diameter of the bed-material particles were 

decreased by the addition of bentonite as the fine sediment. The forms of bed roughness, resistance to flow 

in terms of a dimensionless form of Chezy's coefficient 
D-18 GEOLOGlCAL SURVEY RESEARCH 19 61 

1.0 p---ff 

0.8 

0.6 

en 

a:: 0.4 Li.J 

1-

Li.J 

~ 

:::i 

I I I I I v / 

BENTONITE, IN PERCENT dso C7R 

0 

0 

~ 

0 

5 

1 

0.282 

.187 

.269 1.59 

1.61 

1.64 ' 

~ ~ ~ / / • 10 .107 1.78 87 / Temperature=24°C / 

~R = ( dso + da4 )(t) ~ 6/' ...J 

. d16 dso ....,. / ~ :E 

~ 

a: 

Li.J 

~ ~ v / 

v 

~ ~ ./ v 0.2 1-

Li.J 

:::2: 

<( 

0 ~ v ~ / / 

~ / v ...J 

...J 

<( 

u... 

0.1 ~ / / ,/ 

/ I / / 

0.08 

~ / ./ / ! 

/ ~ ...,. . 

./ 

/ / 

0.06 tf ~ 

0.050 .01 0.1 

I 

2 5 10 20 40 60 80 90 95 

PE.RCENT..fiNER. 

I 

FIGURE 300.1.-The particle size distribution of an Elkhorn River, Nebr., sand sample based on its fall velocity in various 

concentrations of bentonite dispersed in distilled water. (Analyzed in the visual-accumulation tube.) 

of discharge, 0 jVg, and concentrations of the total 

bed-material transport are given in table 300.1 for the 

water-sand flow w~th bentonite and without bentonite. 

When sufficient . bentonite was added to the watersand mixture the resistance to flow and the total bedmaterial in transport decreased in the lower flow 

regime with ripples and dunes and increased in ·the 

upper flow regime with standing waves and antidunes. 

(See Art. 165.) The addition of bentonite. changed 

the transifion dunes to a plane bed and the flow changed 

from· the lower to the upper regime. Also, the form of 

bed, resistance to flow, and bed material in transport 

for the water-sand flow with bentonite and a coarse bed 

material were similar to those developed in flume experiments using water and finer bed materials. Comparison with experiments in an 8-foot-wide flume 

(Simons and Richardson, 1960) shows that the median 

fall diameter of this finer bed material for similarity of 

flow and transport phenomena would be the .same as 

the effective median fall diameter of the coarser bed 

material in the water-bentonite dispersion. 

.The use of the effective size or actual fall velocity of 

the bed material leads to a more thorough understanding and explanation of phenomena that occur in natural 

streams, including seasonal variations. At a nearly 

constant discharge, a change occurs in bed form, resistance to flow' and sediment transport between summer 

and winter flows in the Loup Rivers of Nebraska (Hubbell, 1960). The fall velocity and, therefore, effective 

size de~reases with the decreasing water temperatures 

during· the autumn and winter because viscosity increases with decreased temperature. The form of bed 

roughness changes during the winter to conform with 

the smaller effective size, and, therefore, the resistance 

to flow decreases and the amount of bed material in 

transport increases. 

The fall velocity and the effective fall diameter of 

sediment particles decrease with increase in the viscosity of the liquid. In natural streams viscosity is increased by increase in the load of fine sediment, or by 

decrease in temperature. The apparent viscosity of 

aqueous dispersions of fine sediments depends, therefore, 

mainly on concentration, temperature, composition and 

structure of the clays, state of flocculation and neutralization~but it is complicated by many other factors. 

(See Bingham, 1922; Hermans, 1953; Street, 1958; and 

'· 

·I 

. 
I 

SHORT PAPERS. IN THE GEOLOGfC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-19 

TABLE 300.1.-The effect of concentration of bentonite on form of 

bed roughness, resistance to flow, and total bed-material transport 

in flume studies 

Concentration 

Flow regime and concentra- Resistance of total 

tlon of bentonite in the Form of bed to flow bed-material 

water-sand flow (parts roughness (Civg) discharge 

per million) (parts per mlllion) 

Lower regime: 

Without bentonite ___ Ripples. _______ 10. 4 12 

4,800 ppm bentonite_ Rounded ripples_ 14. 4 2 

Lower regime: 

Without bentonite ___ Dunes __ - ______ 8. 5 . 1, 020 

63,700 ppm ben- Rounded sand 12.4 521 

tonite. waves. 

Transition: 

Without bentonite ___ ---------------- 8. 1 1, 700 

44,100 ppm ben- Plane __________ 12. 7 2,960 

tonite. 

Upper regime: 

Without bentonite ___ Standing waves_ 15. 7 3,330 

58,700 ppm ~en- Antidunes ______ 12. 3 22,300 

tonite. 

Upper regime: 

Without bentonite ___ Antidunes. _____ 12. 5 9, 180 

51,900 ppm ben- Violent anti- 9. 0 50,000 

tonite. dunes. 

Wood, Granquist, and 1\::rieger, 1955.) The apparent 

viscosity of 0.5-, 1-, 2-, 3-, 5-, and 10-percent bentonite 

an:d 3-, 5-, and 10-percent kaolin (by weight) dispersions in water were measured with a Stormer Viscosimeter. At a temperature of 20° C, the viscosity of· a 

· 5-percent (by weight) aqueous dispersion of bentonite 

is about 2.5 times greater than that of distilled water 

and a 5-perc.ent dispersion of kaolin is about 1.5 times 

more viscous than distilled water. 

The visual-accumulation tube for the direct determination of the effective fall-diameter distribution was 

·used in a number of tests. Test conditions were controlled so that the settling velocities of the three sand 

samples depended only on the characteristics of the 

sedimentation medium, which were varied by using 

different concentrations of aqueous dispersions of 

bentonite or kaolin. The variation of median effective 

fall diameter as determined from these tests is shown 

on figures 300.2 and 300.3. 

Also shown on figures 300.2 and 300.3 are the effective 

median fall diameters computed from the fall velocities 

by use of the empirical relation between the drag coefficient and the Reynolds number given in a report of 

the United States Inter-Agency Committee on Water 

Resources (1957, fig. 1). The agreement between the 

computed and the measured effective median fall di~­

eters indicates that the size distributions obtained in 

the visual-accumulation tube closely approximated the 

true effective fall diameter distributions. 

Elkhorn River, Nebr. 

Poudre River, Colo. Poudre River Colo. 

10·~~~----~~------~~-L~----------~10 

0.06 0.1 

0 V·A TUBE ANALYSIS 

e COMPUTED 

d, IN MILLIMETERS w, IN CENTIMETERS PER SECOND 

FIGURE 300.2.-Variation of effective fall diameter and fall velocity with change in percent of bentonite in water. 

8 
D-20 GEOLOGICAL SURVEY RESEARCH 19 61 

2 

4 

6 

0.1 

Elkhorn River, Nebr. 

Poudre River, Colo. 

d, IN MILLIMETERS 

0 V-A TUBE ANALYSIS 

e COMPUTED 

2 

f.-

z 

1<.1 

4 (.) 

a:: 

1<.1 

a.. 

~ 

z 

::::; 

0 

c( 

~ 

6 

w, IN CENTIMETERS PER SECOND 8 

FIGURE 300.3.-Vari:ition of effective fall diameter and fall velocity with change in percent of kaolin in water. 

The influence of temperature on effective fall diameter in distilled water can be determined from the information given in the above-mentioned report. Preliminary results ind~cate that ,the particle-size 

distribution of light-weight bed m.aterials in terms of 

effective fall diameter:s can be obtained directly from 

analyses made in the visual-accumulation tube. 

REFERENCES 

Bingham, E. C., 1922, Fluidity and plasticity.: New York, McGraw Hill. 

Hermans, J. J., 1953, Flow properties of disperse systems: New 

York, Inter-Science Pub., Inc. 

Hubbell, D. ,V,, 1960, Investigations of some sedimentation 

characteristics of sand-bed streams-Prog. Rept. No. 2: 

U.S. Geol. Survey open-file rept., p. 21-36. 

Simons, D. B., and Richardson, E. V., 1961, Forms of bed 

roughness in alluvial channels: Am. Soc. Civil Engineers 

Jour., v. 87, no. 3, p. 87-105. 

Street, Norman, 1958, Viscosity of clay suspensions: World Oil, 

V. 147, p. 151-156. 

United States Inter-Agency Committee on Water Resources, 

1957, Some fundamentals of particle-size analysis-a study 

of methods used in measurement and analysis of sediment 

loads in ·streams : Rept. 12, 55 p. 

'Vood, W. H., Granquist, W. T., and Krieger, I. M., 1955., Viscosity studies on dilute clay mineral s~spensions: Natl. 

Acad. Sci. Natl. Research Council, Pub. 456, p. 240-250. 

' 
•· 

SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-21 

301. QUALITATIVE EFFECTS OF TEMPERATURE ON FLOW PHENOMENA IN ALLUVIAL CHANNELS 

By D. W. HUBBELL and KHALID AL-SHAIKH ALI, Fort Collins, Colo. 

Laboratory and field investigations have shown that 

flow phenomena. can change significa!ltly when the 

water temperature changes. Lane and others ( 1949) 

reported that for comparable tnean daily discharges in 

the Colorado River, daily suspended-bed-material discharges are from two to three times greater in the 

winter than they are in the summer. Straub (1954) 

found similar increases in the ~1issouri River. Studies 

on the Middle Loup River (Hubbell and others, 1956) 

indicated that total bed-material discharges as measured at a turbulence flmne, as well as suspended-bedmaterial discharges, are greater at low water temperatures than they are at high temperatures, and that flow 

resistance is the least at low temperatures. However, 

in laboratory studies, flo (1939) found that total bedmaterial discharges increase as the water temperature 

increases, and M. G. Mostafa (written communication, 

1949) concluded that a fluid having a high viscosity 

would in n1ost cases transport a lower total bed -1naterial 

discharge. than a fluid having a low viscosity; in other 

words, an increase in water temperature should usually 

increase the total bed-material discharge. 

Because of the contrary findings, a laboratory study 

was undertaken to examine temperature effects 

throughout a wide range of flow conditions. The study 

was conducted in a recirculation-type flume that is 2 

feet wide and 60 feet long. Temperature of the watersedilnent 1nixture was controlled by adding either 

steam or cold water to the system. The bed material 

used in the study was sand from the bed of the Elkhorn 

River near Waterloo, Nebr.; its median fall diameter 

(U.S. Inter-Agency Committee on 'Vater Resources, 

1957) was 0.31 mm. Runs for a range of flow conditions, frmn plane bed and no sediment movement to 

violent nntidunes \ '''ere ma.de in pairs in which temperature was the only variable purposely changed. The 

depth of flow in the initial run of each pair was set at 

about 0.55 feet. 

F.igure 301.1 shows the differences in concentration 

of the total bed-material discharge, flow resistance, and 

bed form· that occurred between the runs in each pair. 

In general, when the bed form was ripples or dunes 

with superposed ripples, the concentration of the total 

bed-material discharge was greatest in the high tern1 Simons ltn<l Richardson (1961) have d~escrlbed each of the various 

hed forms nn<l their attendant characteristics within this range. Onl·Y 

the stnndlng wave form of bed roughness was not investigated in this 

stud•y. 

perature run; when the bed form was dunes or plane 

bed, no general trend was apparent; and when the bed 

form was antidunes, the concentration of the total bedmaterial discharge was greatest in the low temperature 

run. 

The concept of the change in "effective size" with 

tmnperature, and the changes in the concentration of 

total bed-material discharge and the flow resistance with 

shear provide the basis for an explanation of the effect. 

of temperature changes on flow phenomena. 

Experiments with different bed materials (D. B. 

Simons and E. V. Richardson, oral communication, 

1960) have shown that the size of the bed material, as 

characterized by the median fall diameter, affects flow 

phenomena. Because the fall diameter is determined 

from fall velocity, the variations in flow phenomena 

that occur with different fall diameters actually reflect 

the effects of the fall velocity of the bed material. To 

illustrate this point, Haushild and others (Art. 300) 

in a flume experiment with a water-bentonite mixture 

and a bed of coarse material showed that the bed forms, 

flow resistance, and concentration of total bed-material 

discharge were similar to those developed in a flume 

experiment with clear water and a finer bed material. 

In order to express with a linear dimension the equivalency between particles having the same fall velocity, 

they used the term "effective fall diameter" 2

• By 

definition, when ever the viscosity of the stream liquid 

changes because 9f a temperature change, the effective 

median fall diameter changes. Also, two particles with 

different characteristics will have the same effective fall 

diameter if, when they fall in different liquids, their 

fall velocities are the same. 

For a given bed material, channel shape, viscosity, 

and depth, flume experiments have shown that the 

concentration of total bed-material discharge and flow 

resistance vary with shear on the bed. If any of these 

factors change, the relations between concentration of 

bed material in transport and shear and flow resistance 

and shear change. Figure 301.2 shows concentrationshear relations for two different bed materials having 

median diameters of 0.28 and 0.45 ·mm. The curve for 

the 0.28-mm bed material is based on data collected by 

Simons and Richardson. (1961) in an 8-foot-wide flume; 

2 The effective fall diameter of a particle is the diameter of a quartz 

sphere whose standard fall velocity equals the velocity of the particle 

when it falls alone in quiescent stream fluid of infinite extent and at the 

stream temperature. 
D-22 GEOLOGICAL SURVEY RESEARCH 1961 

(.) 

Q 

5r---+---1---~---+--~----~--+---1---~---+--~----r---+---1---~---+--~----r---+-~ 

.5 Dashed linea join related runs 

I I I J I 

8.0 9 10 II 12 13 14 15 16 17 

Flow resistance, C/~ 

... 30 

~ 

0 

~ 25 

20 

~ 

I 

I 

, 

I 

I 

I 

II 

~ 

I 

II 

4~ 

~ 

I ~ ~ I ' 

\ ' \ / I 

I 

~' /I~ \ _I 

~ ·~ 

; t? I' I I rp \ \ ~\ i I 

\~ \\ 

I I \ \ \ I I '\ I I ,I \ \ \ 

I \ \ 

I I l \ \ \ 

I ~ \ e ~~~ ~ , 

~ • \ ~ \ ~ I tt 11 I ! 

15 

... 

~~ ~ 10 

Dashed lines join related runs I ·1 I I I I I II 

10 IZ 13 JO 10 4 

Concentration of total bed-material discharge, 

in parts per million· 

0 

Ripples 

• 

Dunes with 

ripples superpo~~d 

e 

Dunes 

• 

Transition Plane. Mild antidunes Anti dunes 

FIGURE 301.1.-Change in flow resistance and concentration of the total bed-material discharge with temperature for each 

pair of flume runs. 

the curve for the 0.45-mm bed material is based on data 

collected in the same flume (Simons,· Richardson, and 

Albertson, 1961). Both curves are defined for a depth 

range of 0.5 to 0.7 foot and a relatively narrow temperature range. 

The implication of the effective-size and concentration -shear relations is that if the properties of the water 

change through a temperature change, the effective 

median fall diameter changes and the stream adjusts to 

new concentration-shear and flow resistance-shear relations. In the adjustment, the shear, the total concentration, the flow resistance, the bed form, and sometimes 

the flow regime change until an equilibrium is reached 

in which the mutual associations of all variables satisfy 

final concentration-shear and flow resistance-shear relations. For example, consider that in a flume experiment the initial conditions are such that the median 

fall diameter of the bed material is 0.36 mm. Assume 

that when the water temperature is increased to 70° C 

(an extreme case) and the effective median fall diameter 

of the bed material changes to 0.45 mm, the concentration-shear relation becomes that given on figure 301.2, 

in which value "a" represents the shear. If the temperature is decreased to 0° C, the effective median fall 

diameter would be reduced to 0.28 mm and if the slope 

decreased slightly because of the change, the shear 

would decrease slightly, say to value "b", and the concentration would decrease from 240 to 64 ppm. Or, if 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-23 

0 

0 

-

~ 0 

::J 

0'" 

&n 

~ 

Q) 

Q. 

&n 

"0 

c 

5 

1.0 

c 

d 

Q. 

.5 0.1 

a 

b 

i-

--

-1-- -Ir--rr--~ 

-

---- -----

------ - -----I-- ---= 

---< r--~ 

-~ - -

10 

-1- r- ----r------ 1-- - 1----

.J~ 

~ ..... I' / 

/J le' ..... ~ 

~ v - ,::F-pi-' ~-:.4 -I ~ I 

H~ I ~~- - J 

I I 

I I 

I I 

I 

100 1,000 

I 

I 

/ I 

v i 

/ I 

y 

-- - - 1- --1- f=--;;4 --7 Q_ 

~ .... 

~I ~ ~ I _./'1 I I 

v ~I v I ! 

~ ~ .... I I 

V' v ~ I I I 

/ A I I I 

./ --. ~ · Forms of bed roughness n= - ./'1 

0.28mm11 0.45mm!l - W-- 0 Ripples G H--- e Dunes ~ Q Transition iii +-I- () Plane -L--- [J 

• Anti dunes I • I 

II 

- Flow depth 0.5-0.7 ft. 

lJ Median fall diameter II 

I of bed material I 

1opoo 60/JOO 

Concentration of total bed-material discharge, in parts per million 

FIGURE 801.2.-Relation between bed shear and concentration of total bed-material discharge in an 8-foot-wide :flume for 

relatively constant water temperature and depth. 

the shear at the hot-water temperature is given by "c" 

·and the change in slope when the temperature is 

decreased to 0° C causes a decrease in shear to "d", the 

concentration would increase from 20,000 to 43,000 ppm. 

However, if the depth also changed with the decrease in 

temperature, the changes in concentration could not be 

predicted because alterations in the other variables 

would cause an adjustment to a new, undefined, concentration-shear relation. 

REFERENCES 

Ho, Pang-Yung, 1939, Abhanglgkeit der geschiebebewegung von 

der kornform und der temperatur (Dependence of bed-load 

movement on the grain shape. and the temperature) : Mitteilungen der Preussischen Versuchsanstalt fur Wasser-, 

Erd-, und Schiffbau, Berlin, v. 37. 

Hubbell, D. W., and others, 1956, Progress report number 1, 

Investigations of some sedimentation characteristics of a 

sand-bed stream: U.S. Geol. Survey open-file report, 78 p. 

·Lane, E. W., Carl!:fOn, E. J., and Hanson, 0. S., 1949, Low temperature increases sediment transportation in Colorado 

River: Civil Eng., v. 19, p. 619-620. 

Simons, D. B., and Richardson, E. V., 1961, Forms of bed roughness in alluvial channels: Am. Soc. Civil Engineers Jour. 

v. 87, no. 3, p. 87-105. 

Simons, D. B., Richardson, E. V., and Albertson, M. L., 1961, 

. Flume studies using medium sand (0.45 mm): U.S. Geol. 

Survey Water-Supply Paper 1498-A, 76 p. 

Straub, L. G., 1954, Terminal report on transportation characteristics of Missouri River sediment: University of Minnesota, Missouri River Div. of Corps of Engineers, U.S. Army, 

M.R.D. Sediment Series no. 4, 53 p. 

U.S. Inter-Agency Committee on Water Resources, 1957, A 

study of methods used in measurement and analysis of 

sediment loads in streams ; some fundamentals of particle 

size analysis : Rept. 12, 55 p. 
D-24 GEOLOG:fCAL SURVEY RESEARCH 19 61 

302. DISPERSION-MOTIVATED FLUCTUATIONS OF GROUND-WATER LEVELS IN WELLS 

By F. A. KoHOUT, Miami, Fla. 

Work done in cooperation with Dade County, Florida 

There are many generally known causes of fluctuation 

· of ground-water levels. Some of the more common are 

recharge by rainfall, pumping, tid~l action, earthquakes, evapotranspiration, and changes in atmospheric 

pressure: In areas of salt-water contamination, fluctuations of water level may be caused, also, by dispersion 

phenomena in the casing of wells that tap the zone of 

diffusion between fresh and salt water (fig. 302.1) . 

Generally, the cause of water-level fluctuations of this 

kind is obscure in that the fluctuations are related 

directly not only to changes in ground-water potential, 

but also to the density of water in the observation well. 

Thus, careful interpretation is required to insure that 

water-level measurements are meaningful. The purpose of this paper is to illustrate how dispersion may 

cause a change of water level in a well. 

FLUCTUATION INDUCED BY PUMPING 

In the course of routine water sampling, certain wells 

in the Miami area, Florida, appeared to have residual 

water-level dra wdowns of several tenths of a foot after 

being pumped. Owing to the high permeability of the 

Biscayne aquifer in .the Miami area ( 50,000· to 70,000 

gallons per day per square foot) residual drawdo~ns 

of this magnitud~ are not expected as the result of 

pumping for short periods at low rates. In wells 

DISTANCE FROM BAY, IN FEET 

12.000 10,000 8000 6000 4000 2000 

20' 

-20' 

-40' 

-60' 

-80' 

-100' 

FIGURE 302.1.-Cross section through the Silver Bluff area, 

Miami, Fla., showing the zone of diffusion, November 2,1953. 

equipped with continuous water-level recorders no 

recovery from pumping levels occurred (fig. 302.2). 

After repeated pumpings (each one producing a similar 

dra wdown), no persistent decline of water level relative 

to other wells was detected. 

The reason for the drawdown and lack of recovery 

is apparent in figure 302.3 in which the water levels 

of wells F198 and F192 are plotted against the chloride 

concentration of water in the casing of well F198. 

Well F192 is a short distance from well F198 and is 

used to determine the regional fluctuations of water 

level. Before well F198 was pumped on March 12, 

its water level was 0.21 foot higher than that in well 

F192. After pumping stopped, the chloride content 

(and consequently the density) of water in the casing 

of well F198 had increased to 7,950 ppm (parts per 

million) and the water level was 0.16 foot lower than 

that o·f well F192. During the afternoon of March 12 

and on March 13 and 14, the water in the casing fresh-

·~ 

·~ 

d 

JANUARY 1950 FEBRUARY 

27 28 29 3o I 31 

1.91--_:-"""="'"=----+-r---=--+-~---JL---j----l-----t---t-----! -......___ r--~Pumped 

1.81-----+---f-----l--==-:t-r------t-----t---t-----! 

ul----l----f-----i---1--~+1--- __ ,,._:::=.._~=-:----! r:--

JUNE 1950 

2 3 4 5 6' 7'. 8 9 

~ 1.9 

~ ~ 1. 

"-0 1. 

8 

7 

1.3 

2 

- t---r---

7 8 9 

:---~Pumped .. ....--

JULY 1950 

10 I 11 12 13 14 

I..---__j,Pumped 

..........._ ..........._ 

- FIGURE 302.2.-Hydrographs showing residual drawdown of 

water level caused by dispersion after pumping well G580. 
., 

SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-25 

~ 2.0 ~ 

~ 

.J 

...., 

> ...., 

-l 

IX 

...., 1.5 t-

~ 1.1.. 

0 

...., 

0 

:::1 

ti= 1.0 -l 

c( 

8000 

z 

~~ C2 3 6000 t--

...., 

z~ 

(.)IX 

z ~ 4000 8(/) 

...,to IX 

0: ct 2000 

9z 

xu 0 

.. ... --- -··· . 

/ "\,. Water level in well 

,......, "--v ~ 

~ 4 v ""' I'./ "'-.../ ~~,.... 

~-irv---::- 'water F 

level 

192 in well -

~ 

\- _.-Sollected in the casing of well F 198 at -26.3 It M S L 

\ ___ "'"-

----c ----I ---o 

5 10 15 20 25 301 1 5 10 15 20 

I MARCH 1954 APRIL 1954 

FIOUttE 302.3.-Density of water, drawdown, and recovery of 

water levels in well Fl98. 

ened so rapidly that the daily-average water level rose 

in opposition to the regional decline in water level, as 

shown by the hydrograph of well F192. Subsequently, the hydrographs of the two wells gradually 

diverged as the chloride content of the water in well 

F198 ·decreased to its pre-pumping concentra-tion. 

This test clearly shows that the water level of a well 

fluctuates as a result of dispersion-motivated changes 

in the density of the water. In most wells, the recovery of water level resulting from dispersion is imperceptible from water-stage data and can be detected only 

by comparison with water levels in companion welJs 

or by continuously monitoring the density of water 

in the well. This emphasizes that in studies of aquifers containing water of highly variable quality, considerable care must be taken to assure that observed 

water-level fluctQations truly represent changes in 

ground-wn.ter potential. 

WATER-LEVE~ FLUCTUATIONS UNDER 

NATURAL CONDITIONS 

The dispersion rate sho";n in the test on well F198 

was considered to be of significance to analysis of waterstage data, and it directed attention to whether the 

upward rate of dispersion in the well was as great as 

604493 0-61-3 

the downward rate. A test was devised to observe the 

relative rates of dispersion with and against the pull of 

gravity. The test consisted of collecting water samples 

in and below the casing of well F192 and comparing the 

water level of well F192 with that of another well that 

was not affected by the change in density. It was expected that a rapid freshening of the water in the 

casing would occur when the salt-water front (fig. 

302.1) was pushed seaward by the high water-table conditions during the rainy season. The dispersion in this 

case would be downward, aided by gravity. As the 

water table declined below a certain critical altitude 

the salt-front movement would reverse, and the chloride 

concentration of water in the aquifer below the bottom 

of the casing would increase to a higher value than that 

of water in the casing. The dispersion in this case 

would oppose gravity . 

On figure 302.4 ( p. D-26) , the changes in chloride 

concentration of water in and below the casing of well 

F192 are compared with the difference in water level 

between wells F192 and G294. Since well G294 is a 

shallow fresh-water well at the same location as F192, 

changes in its water level reflect true changes in groundwater potential and may be used for comparison. The 

difference in water level between the two wells, then, 

shows the· fluctuation of water level caused by dispersion of salt water in the casing of well F192. 

The high water levels of late September and October 

1953 produced a sharp decrease in chloride content at 

the 60.7-foot depth in well F192. The decrease in 

chloride content at the 46.7-foot depth (in the casing) 

lagged only slightly behind. In comparison, the 

difference in water level between wells F192 and G294 

decreased in direct relation to the freshening of the 

water in the casing of well F192. 

· Between December 1953 and May 1954, the chloride 

concentration below the casing gradually increased approximately 4,000 ppm; during the same period, the 

chloride content of the water in the casing increased 

less than 300 ppm. The upward rate of dispersion in 

the casing of well F192 apparently was much slower 

than the downward rate. However, the water-level 

difference between the wells increased in relation to the 

increase in chloride content of the water in the casing. 

This is shown by· the upward trend of the difference 

curve from January to l\iay 1954, before ·rainfall 

started another cycle. Thus, under completely natural 

conditions, the water level in a salty well may fluctuate 

by a dispersion mechanism that is not entirely dependent on changes in ground-water potentials. 
D-26 GEOLOGICAL "SURVEY RESEARCH 1 9 61 

(/) 13,000 1-

Q:· 

~ C\1 12,000 

Z ~ ll,OOO -_u.. 

~ j 10,000 

-L&J 

!;(~ 9000 

Q: - t-z 8000 zo 

L&J - u....J 7000 z= 

0~ 6000 UQ: 

L&JL&J 5000 oa.. 

~ 4000 0 ....J 

~· 

' 1\ Collected at -60.7 ft mean 

, .. ~ ~ ,.,.... sea level (below casing) 

\\ /~ \ 

'i / \ 

\:, / I" ........ ~-- - ~ v 

~-~-o--o- --~- -o-- o •• .o-o-.o--o--o ...o ...... o ... o •• o- o----o---- o----~ 

~ . 

Collected at -46.7 ft mean " ~ .. v- sea level (in casing) -___,r.'_ o---..o---o :I: 3000 u 

0.9 

u.i 

u 0.8 z 

L&J 

Q: 0.7 L&J 

u..l- 0.6 !::!:::L&J 

OL&J u.. 0.5 ....J 

L&JZ 

>- L&J 0.4 ....J 

Q: 0.3 L&J 1-<( 0.2 

~ 0.1 

~ \ 

\ Difference in water level between Y. wells G 294 and F 192 

\ 

~ 

~ ..... .A. ~ ..... ....... ....._ ......,. ._. .... ~ '~ v'-~ 

"~ ~ 

~ 

5 

L&J 

> o....J 

alL&J 4 <(> 

-L&J 1-....J 

L&J 

·~ ~ 3 z(/) 

v,\\ ~ . J / \ .. \ Water level in well G 294 

-z 

....:~ 

a~ 2 

Lij 

:I: 

SEP OCT NOV DEC JAN FEB MAR APR MAY JUNE JULY AUG SEP OCT 

1953 1954 

FIGURE 302.4.-Fluctuations of water level due to dispersion in well F192 for natural conditions. 

303. DISPERSION WITH OSCILLATING FLOW IN A GRANULAR MATERIAL 

By WILLIS K. KULP, :Oenver, Colo. 

To explain the discrepancy between observed and 

calculated intrusion of salt water into some coastal 

aquifers, Cooper ( 1959, p. 461) states that the dispersion of salts produced by oscillatory motion of the saltwater front in a coastal aquifer induces a salt-water 

flow from the sea floor into the zone of diffusion and 

back to the sea. The experiment reported here gives 

the coefficient of dispersion of salt at the boundary between bodies of salt and fresh water in oscillatory 

motion in a granular material. 

A lucite ~olumn 4 inches in diameter (A, fig. 303.1) 

was filled with Ottawa sand, a sieved sand having an 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-27 

1 FOOT 

Salt-water reservoir 

Position of 

original interface B 

FIOUI~E 303.1.-Apparntus used to measure the coefficient of 

dispersion. (Letters are explained in text.) 

effective grain size of 0.70 mm, a Hazen uniformity 

coefficient of 1.03, and a porosity of 36.5 percent. An 

interface was established near the center of the column, 

B, below which the sand was saturated with salt water 

containing 200 pa.rts per million potassium chloride, 

and above which the sand was saturated with fresh 

water. The bott01n of the column was connected to a 

salt-water reservoir, 0, through flexible tubing. The 

reservoir was moved up and down by means of a cable 

nttached to a rotating wheel, D, at the ;rate of one cycle 

per hour. The fresh water and salt water in the sand 

oscillated a,t the same frequency as the water level in 

the reservoir. The amplitude of the water in the sand 

was 0.63 foot, the amplitude of the reservoir water level 

was 0.4 7 foot, and the amplitude of the free water surface in the column was 0.23 foot. The time lag between 

water-level fluctuations in the reservoir and those in 

the column was determined experimentally prior to the 

test and the test was started with this time lag already 

present so dynamic equilibrium was reached instantaneously. The conductivity of this water was measured 

by electrode pairs spaced along the length of the column. 

At the end of the first, second, fourth, sixth, and eighth 

cycles, the movement of the interface was temporarily 

interrupted and conductivity profiles were observed by 

switching a recorder to each electrode in turn. Calibration of the electrodes permitted determination of 

the concentrations of salt at the electrode positions. 

Figure 303.2 shows the concentration of salt in the 

column at the end of eight cycles. The relation is 

given by: 20 X 1--=erf--=erf u 

Go 2$t (1) 

in which xis the distance in feet from original interface 

measured positively in the direction of decreasing concentration; D is the dispersion coefficient i.r{ square 

feet per second; tis the elapsed time in seconds; 0 is the 

concentration at distance x in parts per million; and Oo 

• is the initial concentration of salt solution in parts per 

million. By definition, 

,- x2 

u=x/2-vDt, or D= 4tu2 (2) 

The u and x values in equation 2 are the points common 

to curves determined by plotting u versus erf u and the 

20 

absolute value of x versus the absolute value of 1- Oo · 

The latter curve is detennined using concentration 

values for potassium chloride measured at one particular time. Figure 303.3 shows the two curves in matching position for t=28,800 seconds. The match-point 

coordinates are U=1.02, and x=0.38. These values, 

ELECTRODE PAIR POSITIONS 

"16 1,5 

12 9 14 131111 1

Pd 7 z ~ 0 

3 • ~ • 

ffi Position of original interface Q.. 50 -

---- ~ a: 

<C • IQ.. 

~ 100 - z 

0 • ~ f5 150 - <...) 

·~ <...) 

c::; 200 .. . :.:: I I I I 

1.5 1.0 0.5 0.5 1.0 1.5 

DISTANCE, IN F~E1. FROM ORIGINAL INT~RFACE 

FIGURE 303.2.-Distribution of potassium chloride at the end of 

eight cycles. 
D-28 GEOLOGICAL SURVEY RESEARCH 19 61 

1.0 

0.1 

O.Ql 0.1 1.0 

..... _""'"""-,, ___ ,., ___ ,.... ..... _ --, 

0.1 u 

Coordinates of match point 

x:::0.38 

u:::l.02 

1.0 

I 

Q) I 

I 

I 

I 

I 

I 

I 

10.0 

10.0 

1.0 . 

~8 I 

.... 

0.1 

FIGURE 303.3.-Matching of observed values of lxl versus 11-~~ 

and u, versus erf u, for t= 28,800 seconds. 

substituted in equation 2, result in a dispersion coefficient of 1.204 X 10-6 ft2 per second or 0.00112· cm2 per 

second. 

The average interstitial velocity (v) can be determined 

by the formula 

_ 4xn 

V=-

tcp (3) 

in· which x is the amplitude of the free water surface 

above the sand in centimeters; n is the number of cycles; 

t is the tim·e, in seconds, required for n cycles; and cp 

is the porosity. Using this formula, the average interstitial velocity for the experimental conditions is 0.213 

em per second. 

Figure 303.4 compares the results of the experiment 

with the relation reported by Rifai and others (1956, 

p. 90) between the dispersion of salt and the average 

interstitial velocity in Ottawa sand under conditions of 

unidirectional flow. ·The effective grain size for the 

Ottawa sand used by Rifai and others (1956) was 0.45 

mm, which is somewhat smaller than that of the sand 

used in this study, but the uniformity coefficient-a 

much more critical value (Orlo b and Radhakrishna, 

1958, p. 656)-was 1.30. This value is very nearly the 

value of 1.03 for the sand used in the present experiment. Although to date the st.udy is inconclusive, the 

close comparison of results shown on figure 303.4 indicates that dispersion takes place at about the same rate 

in oscillatory motion as in unidirectional motion. 

I I I I I I I I I I 

- -

600- ..... 

Cl 

z 

0 

u - - .... 

en 

0:: 

~ 400- - N::!E 

u 

7 - - 8 

~ 200- -

I- ~Experimental results, present study -

,poo I I I I I I I I I I 

0 200 400 600 800 1000 

V X 10 -• CM PER SECOND 

FIGURE 303.4.-Comparison of experimental results with data 

of Rifai and others (1956). 

REFERENCES 

Cooper, H. H., Jr., 1959, A hypothesis concerning the dynamic 

balance of fresh water and salt water in a .coastal aquifer: 

Jour. Geophys. Research, v. 64, no. 4, p. 461-467. 

Orlob, G. T., and Radhakrishna, G. N., 1958, The effects of entrapped gasses on the hydraulic characteristics of porous 

media : Am. Geophys. Union Trans., v. 39, no. 4, p. 648-659. 

Rifai, M. N. E., Kaufman, '"'~. J., and Todd, D. K., 1956, Dispersion phenomena in laminar flow through porous media : 

California Univ. Sanitary Eng. Research Lab. Div. Civil 

Eng., Prog. Rept. no. 2, 157 p.~ July 1. 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGl!C SCIENCES, ARTICLES 293-435 D-29 

304. CHEMICAL CHARACTER OF PRECIPITATION AT MENLO PARK, CALIFORNIA 

By H. C. WHITEHEAD and J. H. FETH, Menlo Park, Calif. 

During the winters of 1957-58 and 1958-59, samples 

of precipitation were collected at Menlo Park, Calif., 

as a part of a study of the influences of precipitation 

on the chemical composition of surface runoff in Western Conterminous United States. Several innovations 

in the definitions of precipitation were instituted which 

are reflected in the analysis of the various precipitation 

phases collected. The sample collector was a sheet of 

semirigid polyethylene about 4 feet square supported on 

a wooden frame, and draining through a polyethylene 

funnel into a 4-liter Pyrex glass bottle. The following 

definitions are required to clarify the terms used ial discussing the ·chemical character of the precipitation 

· collected: 

Precipitation Water-soluble, gaseous, liquid, and solid material that falls from the atmosphere: 

Rain Precipitation that falls as liquid water, and is collected 

on a freshly cleaned nonreactive surface. 

Dry precipitation Precipitation that falls between periods of 

rain. Dry precipitation consists of the water-soluble part 

of dust, occluded gases, and other constituents of unexplored nature that fall on the collector and are washed 

into the collecting bottle by distilled water. Analysis of 

the resulting solution has no meaning in terms of concentration, because the concentration depends on the amount 

of water used to wasb the collector clean. Tbe ratios of 

most constituents probably have significance, however. 

Bulk precipitation A combination of rain and dry precipitation. 

Each of the three phases of precipitation, rain, bulk, 

and dry precipitation, exhibits its own unique character-as was found by a comparison of the three 

phases collected at Menlo Park. Several mterrelations 

were recognized and some correlations made with the 

physical environment. A few examples of these relations are presented below to illustrate the influences operating to produce the chemical character of the 

precipitation. 

Menlo Park is about 30 miles southeast of San Francisco near the south end of San Francisco Bay and in 

the northei·n part of the Santa Clara Valley. This 

valley is one of the largest of the many valleys in the 

California Coast Range region, and follows the general 

north west-southeast alinement of the surrounding 

mow1tn.ins. The Santa Cruz Mountains, ha ~ing a · 

maximum altitude of about 2,000 feet, lie between 

Menlo Park and the Pacific Ocean to the west. The 

Diablo Range forms the eastern boundary of the Santa 

Clara Valley. The valley extends with variable width 

for some 60 miles, and gradually narrows to a point 

about 30 miles south of Menlo Park, where the Gabilan 

Range, the southern extension of the Santa Cruz Mountains, converges with the Diablo Range forming a 

funnel-shaped valley out of which the locally produced 

atmospheric contaminants are carried by the surface 

winds. 

The valley is fairly well isolated from maritime winds 

because of the range of mountains to the west. Also, 

during most of the year, a temperature inversion exists 

along the entire Pacific Coast, having its base at_ an 

average altitude of 1,200 to 1,500 feet. This acts as 

a lid on the valley and contains most of the locally produced air contaminants. Of equal importance is the 

fact that sea salts have little direct chance to invade 

the valley under stable meteorological conditions and, 

hence, have little if any influence on the chemical composition of dry precipitation. In contrast, during the 

winter rainy season, the influence of sea salts is more 

apparent. Consequently, the chemistry of rain collected at l\1enlo Park reflects the influence of the sea 

as well as the effect of the locally produced mineral 

constituents. 

Figures 304.1-304.3 show the general chemical character of the three types of precipitation sampled at 

Menlo Park during the two winters of observation. 

Rain and bulk precipitation are of a mixed type, with 

bicarbonate and chloride the · dominant anions; dry 

precipitation is principally calcium sulfate. 

The variations in the chemical composition of the 

rain at Menlo Park suggest that there are several factors influencing this phase. The proximity of the ocean, 

·coupled with the fact that most of the rainstorms originate in· a maritime environment, would offer a source 

of sodium and chloride. The inference is that the precipitation regime is composed of rain, nucleating in 

clouds rich in carbon dioxide and containing sodiumchloride particles derived from the ocean. The rain 

then falls through air, which at lower levels contains 

varying proportions of continental mineralization, primarily calcium and magnesium salts. Figure 304.3 in-

. dicates that the salts in the air over Menlo Park are 

primarily calcium sulfate. 

The chemical character of dry precipitation collected 

at Menlo Park supports the contention that, except 

during rains, local continental mineralization contributes more material by direct fallout to streams in this 

area than do maritime sources. The contribution of the 
D-30 GEOLOGICAL SURVEY RESEARCH 1 9 61 

2 samples 3 samples 3 samples 10 samples 

CATIONS ANIONS 

PE~(:ENT~GE REA<:;TING VALUES 

FIGURE 304.1.-Graph showing general chemical character of 

rainwater collected at Menlo Park, Calif., 1957-59. 

ocean, as represented by the presence of sodium and 

chlo~ide, is negligible in the diagram (fig. 304.3) that 

illustrates the chemical character of dry precipitation. 

Bulk precipitation represents a combination, in varying proportions, of rain and dry precipitation. Physi~ 

2 samples 

CATIONS ANIONS 

fERCENTAGE REACTING VALUES 

FIGURE 304.2.-Graph showing general chemical character of 

bulg precipitation collected at Menlo Park, Calif., 1957-59. 

CATIONS ANIONS 

PERCENTAGE R~C_TI_N~ V~LUES_ 

FIGURE 304.3.-Graph showing general chemical character of 

dry precipitation collected at Menlo Park, Calif., 1957-59. 

cally, it is dry precipitation washed into the collecting 

vessel by rainwater, and as such, reflects the chemical 

composition of both phases to different degrees. The 

chemical composition of bulk precipitation is dominated 

largely by the bicarbonate ion. The composition of the 

cations is variable and is not dominated by any one ion 

although calcium is most abundant. In the samples 

collected at Menlo Park, bulk precipitation most nearly 

exhibits the properties of the local dry precipitation in 

that it tends toward a calcium-magnesium composition. 

However, rain in this area also is influential in affecting 

the chemical composition of the bulk precipitation. 

This is seen in the trend of some samples toward a 

sodium-chloride composition. 

The division of precipitation into the three general 

categories presented here permits tentative assignment 

of the sources of mineralization reaching the ground 

and the streams in the Menlo Park area. During the 

winter rains, the influence is predominantly maritime, 

as shown by the sodium-chloride character of the available salts. During dry periods, local continental mineralization contributes the major, if not the entire part 

of the airborne salts. In periods of alternately wet and 

dry weather, the influence of both of these sources is 

seen. It seems, then, that bulk precipitation is a more 

meaningful phase of precipitation than rain when considering the contribution of atmospheric salts to the 

chemical character of the surface water. 
SHORT PAPERS IN THE GEOLOGIC ANi> HYDROLOGIC SCIENCES, ARTICLES 293-435 D-31 

305. MECHANICAL UNIFORM PACKING OF POROUS MEDIA 

By DoNALD A. MoRRis and WILLIS K. KULP, Denver, Colo. 

Work done in cooperation with California Department of Water Resources 

Preliminary work during a field and laboratory 

study of the drainage of unconsolidated porous media 

indicated a nonuniform distribution of porosity in beads 

or sand manually packed by tapping the sides of 

columns with a rubber mallet. The resulting porosities 

ranged from 34 to 40 percent, a range considered too 

great for reliable experimental studies. A technique 

for uniform packing of glass beads or natural sand in 

a 60-inch segmented column has been devised that 

utilizes an almost noiseless vibratory packer.- · 

Several kinds of commercial packers, including vibratory n.nd jolting types, were tested, and the vibratory 

packer was selected as the most suitable. The vibratory. 

pn.cker chosen hn.s a pulsating electromagnet and opern.tes at 60 vibrations per second. A rheostat controls 

the vibrntion.nmplitude, which can be varied from 0.04 

to 0.18 em. 

After the operational characteristics of the packer 

were determined for zero-to-capacity loading (300 

pounds), a study was made of the effects of amplitude, 

surcharge, and packing period on the uniformity of 

packing for both short and long columns filled with 

porous media. 

The first tests invo.Lved filling 12 duplicate short 

columns, 14.6 em long and 5.1 em in diameter, with 

0.120-m.m glnss beads, and vibrating them at amplitudes 

ranging from 0.05 to 0.17 em. The resulting porosities 

for the samples ranged from 38.8 to 40 percent. A 

standard packing amplitude of 0.09 em was selected 

arbitrarily. 

The effect of surcharge was determined by comparing porosities obtained with and without a 200-gram 

weight placed on the glass beads during vibration at 

0.09 em amplitude. A difference in porosity of only 

0.8 percent was obtained. The use of a surcharge was 

therefore considered unnecessary. 

The vibration of the columns over periods of from 

5 to 200 seconds at an amplitude of 0.09 em indicated 

that porosity was not appreciably affected by length 

of time of vibration within this range. To minimize 

sorting effects, a standard vibration period of 10 seconds 

was adopted.· 

The technique evolved for packing short columns 

then was extended to the packing of 0.120-nim glass 

beads in columns 60 inches long and 1 to 4 inches in diameter. After packing for 10 seconds at an amplitude 

of 0.09 em, segments of the columns were separated and 

the porosity of'each segment was determined. Figure 

305.1 (p. D-32) shows the distribution of porosity vertically throughout one of these columns which was 1 

inch in diameter. The porosities generally ranged 

from about 38 to 40 percent and averaged about 39 percent. The porosity was quite uniform throughout the 

column and the reproducibility between columns was 

good. The vertical reproducibility of porosity in the 

. 4-inch columns was good, but the porosity ranged more 

widely in the 4-inch columns than in the l-inch columns. 

To test this technique further, duplicate segmented 

60-inch ·columns 1 inch in diameter were filled with a 

natural sand ·(commercially produced by Del Monte 

Corp.), 20-mesh (0.83-mm), and the same packing procedure was followed. The resulting porosities (fig. 

305.2, p. D-32) were somewhat lower (35 to 38 percent) 

than. for glass beads, probably because of the greater 

range of particle sizes and shapes of the sand. The 

porosity was quite uniform throughout the length of 

the column, and again the reproducibility was consistently good. 

A mechanical vibratory packer set at a vibration 

amplitude of 0.09 em and operated for 10 seconds without a surcharge is now the standard method used in 

the laboratory to obtain uniform packing of porous 

media in long columns. 
D-32 GEOLOGICAL SURVEY RESEARCH 19 61 

en 

UJ 

::r: 

(.) 

z 

z 

z 

~ 

::::> 

~ 

0 

(.) 

L&. 

0 

UJ 

en 

< m 

UJ 

> 0 

m 

< 

1-

::r: 

(!J 

~ 

::r: 

65 

60 

55 

50 

45 

40 

35 

30 

25 

20 

15 

10 

5 

0 

30 

• 

• 

• 

--

• 

• 

• 

• 

--

• • 

• 

• 

~ 

-

• • 

• 

• 

~ 

-

• • • 

I 

~ 

-

• 

• 

• 

• 

--

• 

40 50 

POROSITY, IN PERCENT 

JJ"'IGURE 305.1.-Vertical distribution of porosity in a column 

of 0.120-mm glass beads. 

en 

~ 

:I: 

(.) 

~ 

~ 

z 

~ 

;:) 

...J 

0 

(.) 

u. 

0 

~ 

en 

< III 

~ 

> 0 

III 

< 

1-

:I: 

C!l 

i:ij 

:I: 

60 

55 

50 

45 

40 

35 

30 

25 

20 

15 

10 

5 

0 

20 

0 

eo 

., 

eo 

e 0 

• Column 1 

0 

e • 

eo 

Column 2 

0 

e 

0 

i 

0 

e 

0 

e:> 

o• 

• 

., 

~ 

e 

0 

e 

10 

• 

eo 

a 

e 0 

<» 

eo 

0 

0 

• 

e 

30 40 50 

POROSITY, IN PERCENT 

FIGuRE 305.2.-Vertical distribution of porosity in columns of 

20-mesh (0.83-mm) natural sand. 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-33 

GEOLOGY AND HYDROLOGY OF EASTERN UNITED STATES 

306. POST-CAMBRIAN IGNEOUS ROCKS OF THE CENTRAL CRATON, WESTERN APPALACHIAN MOUNTAINS 

AND GULF COASTAL PLAIN OF THE UNITED STATES 

BY M. R. BROCK and A. V. HEYL, Jr., Beltsville, Md. 

Igneous rocks intrude Paleozoic and younger sedimentary rocks at many places in the craton of the 

Central and Eastern Interior, plus the Gulf Coastal 

Plain of the United States. Numerous intrusives discovered by drilling in recent years are not widely 

known. In the course of a comprehensive study of 

ore-deposits controls in this region, the authors have 

searched the literature rather thoroughly for igneous 

rock locaJities and plotted these on a map (fig. 306.1), 

together with the outlines of the mining districts that 

have produced sulfide ores, to see what correlation exists 

between them. 

The intru.sive bodies form stocks, plugs, sills, and 

dikes. Extensive petrographic studies by many persons 

show that the volume of the alkalic group predomimttes over the volume of the subalkalic group in this 

part of the country. This relation is inverse to the 

great preponderance of subalkalic intrusives in other 

parts of the continent and in general throughout the 

world. · 

The twofold division of the igneous rocks into the 

alkalic and subalkalic groups corresponds closely to 

Daly's usage ( 1933). The alkalic rock series is abnormally high in sodium and potassium and deficient in 

silica. The equivalent members in the subalkalic series 

are lower in alkalies and higher in silica. Each of these 

series has been subdivided and plotted on the map with 

distinctive symbols. In addition, intrusive breccias 

that contain igneous material are also shown. 

Intermittent igneous activity in the region took 

place from Ordovician to Quaternary time, but inost intrusive bodies are of Cretaceous age. The intrusive 

rocks that extend southwestward from northern New 

,Jersey through western Virginia to northeastern Tennessee range in age from Ordovician to at least Triassic. 

Many of these have been dated only as post-Ordovician 

or post-Pennsylvanian, depending on the age of the 

rocks they cut. 

Mien. peridotite is spa,rsely distributed in western 

Pennsylvania and eastern 1\:entucky. The small stocks 

in eastern I\:entucky are fresh kimberlite, but those in 

western Pennsylvania are carbonatized. These rocks 

are dated only as younger than the Devonian and 

Pennsylvanian sedimentary rocks that are intruded. 

Dikes and plugs of mica periodotite and lamprophyre in the central Mississippi Valley are believed 

to be either late Paleozoic or Cretaceous in age. A lendalpha age on n1onazite from an intrusive breccia in 

this region suggests a Cretaceous age (oral communication, T. "T· Stern, U.S. Geological Survey), and hence 

the closely associated lamprophyre and peridotite may 

also be Cretaceous. 

A great variety of mostly alkalic rocks in the lower 

Mississippi Valley-Arkansas region intruded sediments 

during the Mesozoic era. Some are believed. to be of 

Triassic age, but most are Cretaceous. The northeasttrending Balcones fault zone in Texas. contains large 

numbers of igneous rocks assigned to both the Cretace~ 

ous and the Tertiary periods. Those in western Texas 

are Tertiary in age and are among several alkalic-rock 

subprovinces of that age along the extensive forelands 

east of the Rocky ~fountains. Northeastern New 

Mexico also contains volcanic rocks of Quaternary age. 

Scattered intrusives between central Missouri and Colorado range in age from early Paleozoic to Cretaceous, 

and possibly to Tertiary. Numerous diabase rocks in 

Florida, Georgia, and Alabama are Triassic and Triassic ( ~) in age. 

The many complex stocks plus transitional variations 

in composition within some dikes are evidence of Inagmatic differentiation and, to a lesser degree, of contamination through partiaJ assimilation of wall rocks. 

Because of the differentiation and contamination it is 

hazardous to assign a specific composition to the source 

melt.. However, studies by I\:ennedy and Anderson 

(1938) on tholeite basalt and olivine basalt show that 

differentiation of the first produces the range of subalkalic rocks and differentiation of the second gives the 

range of alkalic rocks. 

Alkalic rocks are said by Beloussov ( 1960, p. 4136) 

to occur mainly in the platform regions of the world. 

He, among others, considers that the upper portions 

of the mantle are liquid under much of the continental 

areas. Accordingly, the prolonged, more stable conditions under tl~e platform regions could be expected to 

permit a high degree of gravitational differentiation 

within the melt chambers. This differentiation may 

proceed to the point permitting concentrations of the 
I i \ /' 

i 1 NORTH DA K 0 T A 1' I l /---. /~~ PERIOR /' I l ,('i),P ' - ' .JL-- I' 

~------------------------) M I N N E S 0 T A j '·---.......___ I '-1 

-------- I ./ ~-~.. __ -::~-~ \., , 11. : "· ( .y + O 1 0 

o•~ S 0 U T I' , ' I H OAK 0 T A ' '--'- w I s c 0 N s I N ~ I I \ • 

I

I I '- ~ I ) 

;-------------------",--""~ ------ --- ----6'• .. ·. . ·,J~ < I ..., ·,:_,. ·. ____ .~._~ 

I \ .. 

' I ' I N E 8 R A \ 0 w A ') I ______ ,_ __ _ 

__ __; . s K A \ / -- I ------ --l \ L • ~ _, \ I NTERlOR \ 

1 

CE~T~I.__ _____ jJ'!P) EASTER~ l \ 0 

;-----------------------\, '( \ ' "'"" : 0 " ' ' • ·;. '-- , " , " " , I I .... \ ', I 

' '1. M I S S 0 U R I \ 

1

1 K A N : ~- ,_r-..,' 

.... . I :: s A s I ·. '.:.. I ,.... ·~ I ' ••• 

u :1.,. ... ' ' ·.::. ".'··.: ...... ~·· • ~ I I · ·· -u_ •, ·~ e ·::'e. ... ', 

0 --.. t._ I .. *- .·fli~'r l 

~ : ..f-F-_:_-_--.=::=:;------------- ---- :._L·~:-----r-__ ~----· : ' ~ QJ) . ; .. }: I : o \ ~ .:-__ ;

I I KLAH ' ~ - I ' 0 M A ' l I I l ARKANSAS •• 

. o : : .. I ~-------· 

"·'--"', I • .. • t:" { ! '--... ~I ..... v. j I 

-...,....·~._.... .. '., ._,, ... ~ . l I 

->(l..n..._ _.r··'...__ • .._ ~ .. jl I l - · .. .,. : •• < I 

,_., • • • .. t •. • I ·~ ... . ..... ,~~ : ~~--------·..--• .:--~~;. ,... I 

: ... ;!.. : 

I ..... ~/ ,. I \ / MISSISSIPPI 

~~~. / \ 

~ ~ .. \~ • ... • ,..-r----~ : ',...:~ ( \., \ .. l.. ••• • 

• ..... 

.. •• 

'-\ ,\' 

I ~ j GULF ---COASTAL 

~ LOUISIA '. 

li 

~- ""'-,' ) '<. I ••• ·=<~ -~~~\ 

\ G u L F 0 f' 

NOR1:\-I 

&-----~---

·---~~ souTH / 

·-, 1 N A ~ \ CAROL 

.~ ~~ x-\... \ . • G 1 A \ 

\ G E 0 R •, 

A LA BAM A~ 

f .. \ . 

I, • • (lCPLAIN--. - -' ---- I \ ____ :-~:- • ~-

~ -. . . 

M E X I c 0 

" ( 

9 5,0 190 1~0 290 MILES 

0 1' /0 

~ 

---c-l----1 .. I 

~ .._ 00 1 zril •• 0 \..) 

't ~ z ' w H 

~-~- >·> -to . 0 . ~ t··o.. 

-~~: 

EXPLANATION 

ALKALI GROUP 

Felsic rocks, mostly nepheline 

syenite and phonolite 

Mafic rocks, mostly nepheline 

basalt, mica-peridotite, and 

lamprophyre 

SUBALKALI GROUP 

. Felsic rocks, mostly granite 

and syenite 

• 

Mafic rocks, mostly 

diabase and basalt 

e Breccia with igneous material 

Mining districts 

~ that have 

produced sulfide ores 

FIGURE 306.1.-Post-Cambrian igneous rocks which intrude sedimentary rocks in the Central and Eastern Interior regions and Gulf Coastal Plain. 

'r ~ ~-

t:; 

~ ~ 

0 

l"'.l 

0 

t"4 

0 

0 

~ r/1 

q 

::d 

<! 

l"'.l 

~ 

::d 

l"'.l 

U2 

l"'.l 

> 

~ 

@ 

.... 

co 

0) 

.... 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-35 

highly volatile elements, including much sodium and 

potassium, in the uppermost levels of the mantle and 

possibly within the lower parts of the crust. Breaching 

of the chambers by deep-seated fractures would allow 

exodus of the low-viscosity alkalic magma, giving rise 

to the alkalic suite of igneous rocks. If the release of 

pressure within the chamber is great and the exodus of 

material rapid, the result will be, in some cases, gascharged highly explosive emanations. The intrusive 

bodies, including explosive breccias, found along the 

fault zone that extends from eastern 1\::entucky into 

central Missouri may well have originated in this way. 

Explosive breccias and volcanic emanations are associated with alkalic rock provinces at many places in the 

world. At least two of the many brecciated domal 

structures, which are distributed over much of the 

craton region between the Appalachian 'Mountains and 

the Rocky Mountains and described as cryptovolcanos 

by Bucher (1933) and others, can be adequately explained by a.~plosive forces originating in this way. 

Except for the two which contain igneous material, 

these brecciated domes have been omitted from figure 

306.1 because of their questionable origin. However, 

the locations of several are shown in another paper 

(Heyl and Brock, Art. 294, fig. 294.1). Most of the 

cryptovolcanic structures of the region are located on 

structural highs of regional magnitude, and at least 

one, in central Missouri, is situated on a large fault. 

Igneous rocks have been found within 8 of the 19 

mining districts shown on figure 306.1. The distribution of the deposits of fluorspar-zinc-barite-lead ore and 

intrusive rocks in the Illinois-l{entucky mining district 

are better shown in another paper by Heyl and Brock, 

Art. 294, fig. 294.2. Other mineralized districts which 

are too small to show on figure 306.1 are closely associated with these intrusives in Texas, l{ansas, Missouri, 

and Pennsylvania. Eleven mining districts, including 

three large producers of ores, contain no known intrusive rock. 

REFERENCES 

Applin, P. L., 1951, Preliminary report on buried pre-Mesozoic 

rocks in Florida and adjacent states: U.S. Geol. Survey 

Circ. 91, 28 p. 

Baker, C. L., 1927, Exploratory geology of a part of southwestern Trans-Pecos, Texas: Univ. Texas Bur. Econ. 

Geology Bull. 2745, 70 p. 

Beloussov, V. V., 1960, Development of the earth and tectogenesis: Jour. Geophys. Research, v. 65, no. 12, p. 4127-4146. 

Bucher, W. H., 1933, Cryptovolcanic structures in the United 

States: Internat. Geol. Cong. 16th, Rept., v. 2, p. 105l:}-1084. 

Byrne, F. E., Parish, K. L., and Crumpton, C. F., 1956, Igneous 

intrusions in Riley County, Kansas: Am. Assoc. Petroleum 

Geologists Bull., v. 40, no. 2, p. 377-387. 

Clegg, K. E., and· Bradbury, J. C., 1956, Intrusive rocks of 

Illinois and their economic significance: Illinois Geol. Survey, Rept. Inv. 197, 19 p. 

Currier, L. W., 1923, Fluorspar deposits of Kentucky: Kentucky Geol. Survey Bull., ser. 6, v. 13, 198 p. 

Daly, R. A., 1933, Igneous rocks and the depths of the earth : 

New York, McGraw-Hill Book Co., 598 p. 

Goldich, S. S., a~d Elms, M. A., 1949, Stratigraphy and petrology 

of the Buck Hill quadrangle, Texas : Geol. Soc. America 

Bull., v. 60, no. 7, p. 1133-1182. 

Gould, c: N., 1923, Crystalline rocks of the Plains: Geol. Soc. 

America Bull., v. 34, no. 3, p. 541~560. · 

Irving, J. D., 1904, Economic resources of the northern Black 

• Hills: U.S. Geol. Survey Prof. Paper 26, 222 p. 

Johnson, R. '"·· Jr., and Milton, Charles, 1955, Dilre rocks of 

central-western Virginia [abs.] : Geol. Soc. America Bull., 

v.66, no.12,pt.2,p.1689-1690. 

Kennedy, W. Q., and Anderson, E. M., 1938, Crustal layers and 

the origin of the magmas: Bull. Volcano!., ser. 2, v. 3, p. 

23-82. 

Knopf, Adolph, 1936, Igneous geology of the Spanish Peaks 

region: Geol. Soc. America BulL, v. 47, no. 11, p. 1727-1784. 

Koenig, J. B., 1956, The petrography of certain igneous dikes 

of Kentucky: Kentucky Geol. Survey Bull., ser. 9, no. 21, 

57 p. 

Lonsdale, J. T., 1921, Igneous rocks of the Balcones Fault region of Texas: Univ. Texas Bur. Econ. Geology Bull. 2744, 

178 p. 

--1940, Igneous rocks of the Terlingua-Solitario region, 

Texas: Geol. Soc. America Bull., v. 51, no. 10, p. 1539-1626. 

Martens, J. H. C., 1923, Study of the igneous rocks of Ithaca, 

New York, and vicinity [nbs.] : Geol. Soc. America Bull., 

v. 34, no. 1, p. 99. 

Moody, C. L., 1949, Mesozoic igneous rocks of northern Gulf . 

Coastal Phiin: Am. Assoc. Petroleum Geologists Bull., v. 33, 

no. 8, p. 1410-1428. 

Stobbe, H. R., 1949, Petrology of _volcanic rocks of northeastern 

New Mexico: Geol. Soc. America Bull., v. 60, no. 6, p. 1041-

1093. 

Tarr, W. A., and Keller, W. D., 1933, Post-Devonian Igneous intrusions in southeastern Missouri: Jour. Geology, v. 41, no. 

8, p. 815-823; 

Thomas, E. P., 1950, Mississippi structures and their relation 

to oil accumulation : Am. Assoc. Petroleum Geologists Bull., 

v.34,no. 7, p.l502-1506. 

Williams, J. F., 1890, The igneous rocks of Arkansas : Arkansas Geol. Survey Ann. Rept., v. 2, 391 p. 
D-36 GEOLOGlCAL SURVEY RESEARCH 19 61 

307. UNDERSEEPAGE ALONG LEVEE 30, DADE COUNTY, FLORIDA 

By HowARD KLEIN and C. B. SHERWOOD, Miami, Fla. 

Work done in cooperation with the Central and Southern Florida Flood Control District 

The initial flood-control project in southern Florida 

was the construction of a levee west of the Atlantic 

Coastal Ridge, to retard the eastward overland flow of 

flood waters from the Everglades. The southern terminus of the levee system is shown on figure 307.1. 

When the flood-control system is completed, a part of 

the excess waters will be impounded in conservation 

area 3 (fig. 307.1), west of the levees. 

A proposed method of flood control in area B, east of 

the levees (fig. 307.1), is to reduce ground-water storage by means of a network of canals and a series of 

. pumping stations. The pumps will be located along 

the levees and w.ill discharge water from area B into 

conservation area 3. Initially, it was proposed that 

. the water stage in area. B be controlled at sea level to 

give flood protection during major storms. · 

In the following, determination of the underflow 

occurring along a section of the levee under 1960 waterlevel conditions is used to predict underflow between 

conservation area 3 and area B for other postulated 

controlled conditions. 

The levee area is underlain to about 50 feet below 

msl (mean sea level) by the Biscayne aquifer, a body 

of highly permeable limestone. The aquifer is floored 

. by relatively impermeable silt. 

Figure 307.2 gives details of the geology near the 

northern end of Levee 30. A marl and muck blanket 

overlies a thin layer of Miami oolite which is·riddled 

by sol uti.on openings. Figure 307.2 shows two thin 

layers of hard, dense limestone from 0.5 foot above to 

3.0 feet below mean sea level. These layers are relatively impermeable, and under comparable hydraulic 

gradients vertical flow of water through them is many 

times less than the horizontal flow through the deeper, 

more permeable rocks. The thin layers act hydraulically as a semiconfining unit that separates the ponded 

water in conservation area 3 from the water contained 

in the deeper, more permeable part of the aquifer. 

The Levee 30 canal was cut through the beds of low 

permeability and probably intercepts all the underflow 

from the conservation area occurring along the northern 

end of Levee 30. Canal flow represents a composite of 

inflow from ground-water storage in adjoining areas, 

and seepage of ponded water through levee materials 

and the permeable Miami oolite. 

Figure 307.3 shows water-level measurements made 

in a line of multiple-depth wells along a line perpendicular to Levee 30. This profile shows the relation 

between the pool in conservation area 3 and the piezometric surface during April 1960, and indicates, by 

equipotential lines, the head distribution throughout 

the section. 

The equipotential lines show that flow through the 

aquifier toward the Levee 30 canal is essentially horizontal except for the section adj.acent to and beneath 

the canal where flow has an upward component. The 

horizontality of the contours in the interval between 

0.5 foot above and 3.0 feet below mean sea level indicates a large vertical head loss caused by vertical flow 

through the dense limestones. Flow through the shallower materials beneath the levee is essentially horizontal and probably occurs chiefly through the Miami 

oolite. 

In January 1960, discharge measurements were made 

at 1-mile intervals in the northern end of the Levee 30 

canal. Piezometric gradients in the aquifer were determined from measurements in_ wells on both sides of 

the canal and levee and are shown on figure 307.4. The 

following is a tabulation of the data [ cfs = cubic feet 

per second; mgd = million gallons per day; ft per ft = 

feet per foot] : 

A. Discharge measurements in Levee 30 canal: 

Total pickup in 1-mile reach (Qt) ___ 176 cfs (114 mgd) 

Seepage visible across berm to canal 

( Q,) --------------------------- lO+ cfs ( 7 mgd) 

Net pickup by ground-water inflow (Qg) 

(Qg) =Qt-Q. --------------------- 166 cfs (107 mgd) 

B. Gradients (I) of piezometric surface 

(fig. 307.4) 

Average, ponded side ______________ 0.0045 ft per ft 

Average, southeast side ____________ 0.0010 ft per ft 

If the aquifer is homogeneous and flow through' it is 

laminar, the quantity of ground water discharging into 

the Levee 30 canal is directly proportional to the 

hydraulic gradie~t; therefore, about 80 percent of Qu 

or 86 mgd represents underflow from the ponded side 

along the 1-mile canal reach. 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-37 

AREA 

N 

~ 

~ ~ 

tv" t ~ ~ ~ 

~ ~ 

EXPLANATION 

c:J 

Report area 

··1--

Canal and control 0 2 3 4 5 6 MILES 

FIGURE 307.1.-Map of northern Dade County showing the area of investigation. 
D-38 GEOLOGICAL SURVEY RESEARCH 19 61 

A DISTANCE. IN FEET 

Io·,----3,o~o ________ ~2oro~--~~~~--------~o __________ I~o~o--------~2o~o ________ _23~oo~--------::A 

6' 

Land surface 

4' 

=~=-=-=-=-=-=-=-=----_-_- _ -_-_-_-_-_-_-_-__ - _____________ _______ _ =-=-=-=-=~=-=-=----=-=-=~=-=-=-= = ----------------=-=-=----_-____ - 2' 

-4' 

u~: X pLAN AT 

1 :.J and-L,, PermeabJ limestone 

Hard; low permeability Low permeability to 50 feet below mean sea level 

-6' 

L1mestone .EZLJ b2Q Fill l -lO'~--~~So-ft;_h_igh_r_Pr~m~ea-bi~lity~--~·~L-ow_p_er_m~ea-bi~lity--~----~--~----~--------~~~~--~-~--~-=--~-~-=-~-=-~--~ .. --.--__1 

- 8' 

FIGURE 307.2.-Cross section showing details of the ~eology near the northern end of Levee 30. 

Darcy's law may be expressed: 

Q=TIL 

ii1 which Q is the quantity of water in gpd (gallons per 

day); Tis th.e coefficient of transmissibility, in gpd for 

each vertical strip of the aquifer 1-foot wide; I is the 

hydraulic gradient, in ft per ft; and L is the length of 

the section, in feet, through which the quantity (Q) 

flows. By substituting in the above equation the data 

of January 1960, a computation 'of the coefficient of 

transmissibility of the aquifer is as follows [ft=feet; 

gpd per ft=gallons per day per foot; ft 2 per sec=feet2 

per second; mgd per mile=million gallons per day per 

mile; cfs per mile=cubic 'feet per second per mile]: 

T ( d f ) Q (gpd) 

gp per t I (ftjft) XL (ft) 

T 86,000,000 

0.0045X5,280 

T =3,600,000 gpd perft or 5.6ft2 per sec 

When water control is in effect in area B there may 

be times when the head difference between water level 

in the conservation pool and water surface in Levee 

30 canal will be as much as 10 feet. To compute the 

expected maximum underseepage it is necessary to determine the relation between the head across the levee 

and the head differential at the toe of the levee under ' different water stages. Figure 307.5 shows this relation. 

The projected graph indicates that if a head differential 

of 10 feet were held across the levee, 'the head differential at the toe of the levee would be 7.8 feet; thus, 

the graqient across the 150-foot levee would be 2.2 feet. 
SHORT PAPERS IN THE GEOLOGI·C AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-39 

c DISTANCE, IN FEET C' 

1800 1600 1400 1200 1000 800 600 400 200 0 10'r------T---------r---------r---------r--------.---------~--------.---------r---------~--~----r---~ 

.- Ponded level-.,. 6.91-..... I ~ "- P1ezometnc surface_.... 4.64 r-- '- Land surface__,.. "' 11/il!jJ' 

SEA LEVEL f==-==-==--=· ,.- ~ ~jill ~:~::>---- --- ---- - -· - -----::::==- --:=..:: ---- .38- 7/T 

(

-- . --- - --:~4:-:.4115.;.:- ./ l J 

o~--4-·-·-

59 

____________________________ ~------~-·-6.3_3 ______ ~-------+--·-5._93--+----4r-,5-.5~9~_,~5~-r~~·~~----+-\~\'--'~--~ \ ·6.36 ·5.93 ·5.585.47. 5};_-!t5.3 

I • 6.34 • 5.95 . 5.57 '·"· ,J 5-fO ·'·" 

-20 1--~\-----l-,----+-, --+----+----l--1-1--+--1 -\-\ ---l 

1.0 '<t C"V 0 co \0 (.11 U1 U1 

b I I 1 I u1 u1 ~ \ 

-30~-----------------,-u~~~~~~-----------------;---------+------~---+---------~---+------~--~ EXPLA~ATION 

Bottom of cased well 5.58 5.44 5.41 5.34 ·6.74 I r6.0--' 

water level ·6.3o ·5.92 ·5.58 • ·5.4.fl. 

40 ~----~--------~-L_in_e_o_f_e~q_ua_l~p~o_te_n_tia_l_(f_e_et_)~--------~----~--~----~--~-L-----L--~----~--~~'------~--~ 

10' 

8; 

6' 

4' 

2' 

SEA LEVEL 

- 2' 

-4' 

-6' 

I . -8' 

-10' 

FIGURE 307.3.-Proflle showing lines of equal potential adjacent to Levee 30, April 1960. 

600 500 400 

------ ---- -r. f--

Ponded level Jan 21, 19601 t:t -- - ( Feb 8, 1960. 

- ~- -- 1,- Piezometric 

<Jan 21. 1960) D -surface (Feb 8, 1960 

Land surface l..J 

. - ... .. -· -· 

300 

~ f-

. ---

DISTANCE, IN FEET 

200 

~- -

100 

LEV££ 

0 

~ ~ -

t;_~ //

0 

. .,.- Berm 

~ ll ~~ -

LEV££ 

30 

·CANAL 

'-....) 

·- -· . ·-~ 

100 200 

{\ 

-

300 

·-· 

FIGURE 307.4.-Proflle showing the relation between ponded water and the piezometric surface adjacent to Levee 30 

during early 1960. 
D-40 GEOLOGICAL SURVEY RESEARCH 19 61 

HEAD DIFFERENCE BETWEEN POOL AND LEVEE 30 CANAL, IN FEET 

~ 

UJ 

UJ 

u.. 

8 

~ 7 

u.i 

UJ 

> UJ 

_. 

u.. 

0 

~6 

~ 

~ 

UJ 

u 

<( 

u.. 

~ 5 (f) 

u 

0: 

~ 

UJ 

~ 

0 

0 2 3 4 5 6 

~ 

,. 

/ 

/ 

/ 

/ 

-

7 8 9 10 

. -

/ 

/ 

/ 

/ , 

/ 

/ 

/ 

~/ 

/ 

/ 

/ 

/ 

G:l4 

a: 

Cl 

z 

<( 

_. 

0 

~ 3 

Jan 21,196'Yr Dec 17,195~ 

/ Feb 8,1960 

z 

UJ 

UJ 

~ UJ 

CD 

UJ 

~ 2 UJ 

0:: 

UJ 

u.. 

u.. 

Ci 

Cl 

<( 

UJ 1 :I: 

0 

/ 

v v 

-. 

/ v 

K. April 19, 1960 

- . --. ·- .. 

FIGURE 307.5.-Graph showing the relation between the head difference across Levee 30 and the head difference between the 

pool and the piezometric surface at the toe of the levee. 

Thus, maximum underflow from beneath the levee 

through the Biscayne aquifer to the canal would be:· 

2.2 ft Q=3,600,000 gpd per ft X 150 ft X 5,280 ft 

Q=279 mgd p~r mile or 432 cfs per :q1ile for a lev:ee 

base width of 150 feet. 

Consideration must be given also to the seepage 

through the levee materials and the layer of Miami 

oolite. An approximate determination of such seepage 

may be made using another expression of Darcy's law 

[gpd per ft 2=gallons per day per foot 2

]: 

Q=PIA 

using an estimated composite coefficient o.f permeability 

(P) of the lev~e fill and oolite=20,000 gpd/ft2

, a length 

of flow section= 5,280 ft, a thickness of flow section 

= 10 ft, a base width of levee= 150 ft, and a head. 

differential= 10 ft, tl:J.e total seepage through the levee 

( Q) is computed to be about 

10ft Q·; 20,000 gpd per ft 2X 150 ftX5,280 ftX10 ft 

Q=70 mgd per mile, or 108 cfs per mile 

The total quantity that will be intercepted along the 

1-mile reach from conservation area 3 is computed to 

be about 349 mgd or 540 cfs. This estimate is based 
SHORT PAPERS IN .THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-41 

on the assumption that flow in the aquifer is laminar. 

For laminar flow the underflow would be directly proportional to the head difference across the levee; for 

turbulent flow the underflow would be approximately 

directly proportional to the square root of the head 

difference. Thus, if there is turbulence in the aquifer 

beneath the levee, flow to the canal will be somewhat 

less than 540 cfs per mile. 

308. SOURCES OF WATER IN STYX AND ECHO RIVERS, MAMMOTH CAVE, KENTUCKY 

By G. E. HENDRICKSON, Louisville, Ky. 

Wor1G done in cooperation with the Kentucky Geological Survey and the National Park Service 

The apparent sources of water in the underground 

streams in Mammoth Cave, Styx and Echo Rivers, are 

ground-water runoff from the sinkhole area- to the east 

of the cave and surface water from the Green River. 

The explored reaches of the underground streams and 

their points of surface emergence are shown on figure 

308.1. The streams come to the surface as springs and 

discharge into Green River. 

The sources were detennined by direct observation of 

direction of flow in the streams, comparison of gage 

heights on Styx, Echo, and .Green Rivers, comparison 

of temperature of water from these streams, and sampling and analyses of waters from the various sources. 

Chemical analyses of waters from the Styx, Echo, and 

Green Rivers yielded the most reliable results because 

the chemical character of water from the sinkhole area 

is quite different fi·om that of Green River water at all 

seasons of the year. 

Before the development of the Greensburg oil field in 

1958 (l(rieger and Hendrickson, 1960), the chloride 

content of water from the Styx, Echo, and Green Rivers 

generally was less than 5 ppm (parts per million). 

After the development of the oil field, however, the 

chloride content of water in the Green River became 

much greater than that of local ground-water runoff 

in the Mammoth Cave area, and a reasonably accurate 

determination of the amount of Green River water in 

the Styx River and Echo River became feasible. 

Figure 308.2 shows the chloride content, temperature 

of the water, and gage height of Styx, Echo, and Green 

Rivers for the period February 1 through June 21, 1960: 

Because of an obstruction in the channel, the gage 

height of the Styx River does not fall below about 423.7 

feet (mean sea level), although the gage heights of Echo 

River and Green River frequently are below 422 feet 

during the summer months. The Styx River 

604493 0-61--4 

apparently flows out of the cave into the Green River 

whenever the gage height of the Green River falls below 

about 423.7 feet. When the Green River is at stages 

higher than 423.7 feet, the Styx River flows in or out of 

the cave, depending on the amount of rainfall at Mammoth Cave, on the amount of rainfall in the Green 

River basin above Mammoth Cave, and in the position 

of the flood crest in relation to the Styx and Echo River 

outlets. The Styx River generally flows out of the cave 

into the Green River immediately following heavy rains 

at Mammoth Cave. Outward flow may continue for 

several days after the rains, but at some time near, or 

shortly after, the highest stage of the flood at Mammoth 

Cave, the flow in the Styx River reverses and water 

flows from the Green River through the Styx "outlet" 

and into the cave. The inflow in the Styx generally 

continues until renewed rainfall begins another cycle 

or until the stage of the Green River falls below 423.7 

feet. 

Changes in chloride content of water in the Styx 

River accompany the reversals in flow, and these changes 

give evidence of. the time· of the reversals. During 

times of inflow the chloride content of the Styx is about 

the same as t~1at of the Green River at this point. During times of outflow the chloride content of the Styx 

generally is considerably less than that of the Green. 

The transition from high-chloride water during inflow 

to low-chloride water during outflow may be abrupt as 

in the period March 15-17, 1960, or gradual as during 

the period April 13-May 7, 1960 (fig. 308.2). Abrupt 

changes from high to low chloride contents are due to 

rapid flushing out by ground-water runoff from sinkholes during local rains, especially during the winter 

months when the soil is nearly saturated with water. 

Gradual cha~.ges are due to the slow dilution of the 

high-chloride water by fresh ground water from the 
D-42 GEOLOGICAL SURVEY RESEARJCH 19 6'1 

800 

EXPLANATION 

® 

Gaging station 

.-----

Explored water passages 

--- Inferred water passages 

0 800 1600 FEET 

FIGURE 308.1.-Styx and Echo Rivers, Mammoth Oave, Ky. 

National Park Service guides have reported a few 

observations of Echo River flowing into the cave. 

Sudden increases in the chloride content of water in 

N Echo River at times when the Styx is flowing out of the 

cave indicate that .such reversal in flow of the Echo 

River does occur. One such reversal occurred on 

May 30 (fig. 308.2), when the chlorides in Echo River 

increased from about 2 ppm to 260 ppm during a period 

of about ~ hours. The Styx River was flowing out at 

this time and had been flowing out for several days. 

Additional evidence of the reversal was the abrupt rise 

in temperature of the water from 54° to 70° F. Such 

reversals in flow in Echo River last only a day or two 

at the most. 

Prolonged periods of high-chloride waters in Echo 

River are undoubtedly caused by Green River water entering the Styx River, flowing through the underground passa¥:es, and discharging through the Echo 

River outlet. Reversals in flow in the Styx are always 

followed by a rise in chlorides in Echo River, generally 

with a time lag of less than 1 day. The time required 

for water entering the Styx to appear at Echo River 

outlet was determined by dye test to be about 15 hours 

when the gage height at the Styx outlet was about 427 

feet. 

When water from the Green River flows through 

the Styx River into the cave and out again through 

Echo River the water discharged at Echo River outlet always is substantially lower in chlorides than the 

water entering the Styx from the Green. During the 

period March 8-12, 1960, chlorides in the water flowing 

from the Green into the cave through the Styx River 

averaged about 150 ppm while water discharging at 

Echo River outlet contained slightly more than 60 ppm 

of chlorides. Local ground-water runoff generally 

contains less than 5 ppm of chlorides. Calculations 

show that about 40 percent of the water discharged 

from Echo River. at this time came from the Green 

River and about 60 percent came from local groundwater runoff. 

REFERENCE 

sinkhole area. It is possible that some high-chloride 

water enters the Styx from the Green at some point 

upstream from the outlet, even during .low stages. 

Krieger, R. A., and Hendrickson, G. E., 1960, Effects of Greensburg oil-field brines on the streams, wells, and springs of 

the Upper Green River basin, Kentucky: Kentucky Geol. 

Survey, ser. 10, .Rept. Inv. no. 2, 36 p. 
SHORT PAPERS IN THE GEOLOGrC AND HYDROLOGIC SCIENCES, ARTICLES 293-43'5 D-43 

'' 

.... 

~ 80 February March April May June February March April May June 

t 10 

i 60 

6 ~0 ... 

•I40 

" 

It\ 1\ A A f.r' 

1/ ll 'J II'.. I"' 

'""v' 

1\ A JiA. 

v "\...AJJ.f v v A' 

v 

280 r-----

240 

~ 200 .'6 

i 

It 160 

~.~ 

I 

.1 

:i 

I~ 120 n I A 

1\ fV "' 80 ,J 

"\ I 

1\ I 

40 41- 1\( 

An 

IV I 1111 " ' 1111 1111 .I '- ~ All 

0 u ,/ -...;:: ~s;;;;;;;;;:;;,; 

.. 435 .. .I\ ,. n 1 

c II 

.c 

"' 430 u 

.c 

-r-lA"" \" 

·~ 

A V\ A 

\. u 

... II ' A II \ 

$ 425 ' \ l I 

;,;,_ ...... _j 

1\ "-

" II I\/ 

-· -=v ~ 

~I'\: l--------t----l----f!--......... ::::::..£./4\,.-o'-l f--- ~-~~---+---4---~---

420 STYX RIVER ECHO RIVER GREEN RIVER ... -- -

Fmmu~ 308.2.-Chloride content, temperature of water, and gage height in Styx, Echo, and Green Rivers, Mammoth Cave, 

Ky., February 1 through June 21, 1960. 

309. VOLCANIC ROCKS OF ORDOVICIAN AGE IN THE MOUNT CHASE RIDGE, ISLAND FALLS QUADRANGLE, 

MAINE 

By E. B.- EKREN, Denver, Colo. 

A belt of vertically dipping volcanic rocks of Ordovician age forms a broad northeast-trending ridge from 

Mount Chase to ShoaJer Mountain (fig. 309.1) across 

the Isln..nd Falls quadrangle. Similar but narrower 

northeast-trending belts occur north of Pleasa.nt Lake 

n.nd Rockabema l.Jnke. Structural relations indicate 

thnt the rocks in the separate belts are part of the same 

strntigm.phic ~quence. The Mount Chase belt is continuous southwestward into the Shin Pond and Stacyville qundra.ngles and outlines a broad south- and southwest-plunging ttnticline (Neuman, 1960). · 

The bulk of the volcanic rock at Mount Chase is dense 

spilite. The spilite, interlayered with thin beds and 

seams of chert, is well exposed along the trail leading 

to the lookout tower at the peak. At places it displays 

poorly defined pillow structure. Eastward along the 

ridge spilite is relatively sparse. There, keratophyre, 

tuffaceous conglomerate, and sandstone make up· the 

bulk of the sequence. Numerous sills of albite- or oligoclase-r1ch diabase intrude the spilite at Mount Chase 

and the pyroclastic and felsic rocks farther east. At 

places along the north west. side of the ridge, quartz 

porphyry crops out. These rocks appear- to be parts 

of dikes and sills extending from a large stock of 

porphyritic quartz diorite (not shown on fig. 309.1). 

Beds of tuffaceous conglomerate and conglomeratic 
D-44 GEOLOGICAL SURVEY RESEARCH 1 9 61 

68°30' OXBOW 

46°15' .-------------------------~-------------, 

-l'" ""' c} 

,.,~"' 

0 

N 

l 

~ Sfioa ler Mt n 

EXPLA N AT IO N 

~ 

Volcanic rocks 

5 MILES 

FIGURE 309.1.-Map of Island Falls quadrangle, Maine, showing outcrop pattern of volcanic rocks of Ordovician age. 

sandstone are generally more abundant in the volcanic 

rocks lying northwest of Mount Chase than along any 

part of the Mount Chase ridge proper. Some sandstone is fossiliferous and yields brachiopods of Ordovician age (Neuman, 1960). 

The Island Falls quadrangle lies in an area of lowo-racle (chlorite zone) metamorphism. 

o Spilite.--The spilite is a dense green rock with diabasic texture (fig. 309.2) in which the plagioclase occurs 

mainly as twinned laths or microlites that range in 

composition from pure albite 1 to about Anl5· Epidote, 

chlorite, sphene, and leucoxene after augite and ilmenite, fill the interstices between the plagioclase grains. 

The original major pyroxene, probably augite, is preserved as tiny fragments. In most specimens ilmenite 

or titaniferous magnetite is extensively altered to leucoxene or leucoxene-coated sphene. Tiny needles of 

actinolite or fibrous amphibole after pyroxene are 

ubiquitous ; quartz is absent except in some vesicular 

rocks where, together with calcite, epidote, and chlorite, 

Plagioclas e compositions in most rocks were determined by comparing indices of refraction against balsam, measuring extinction angles, 

>tnd determining optic sign. A few rocks were ground up and plagiOclase indices determined using index oils. 

0 1 MILLIMETER 

FIGURE 309.2.-Spilite on trail to the lookout tower, Mount 

Chase. Left, Spilite showing considerable range in size of 

plagioclase grains; Right, Spilite consisting mostly of a dense 

felt of oligoclase microlites. 

it fills cavities; pyrite is very abundant in some rocks 

but very sparse in others. The spilite appears to be 

partly reconstituted dense augite basalt in which the 

augite has been altered to epidote, chlorite, and actinolite, and the calcic plagioclase to albite or oligoclase, 

epidote, and calcite. 

Chemical compositions calculated from modes of the 

spilites indicate that the average N a2 0 content exceeds 

4 percent. 

[{ eratophyre, lceratophyre-tuff, and tuffaceous 

1·ocks.--Keratophyre, keratophyre-tuff, and sparse 

tuffaceous conglomerate, and conglomeratic sandstone 

crop out northeast of Mount Chase on the old tote 

roads to Rock{Lbema and Pleasant Lakes. Slaty cleavage is well developed in these rocks and most of the 

fine-grained rocks are highly sheared. Common colors 

are light blue, green, and green gray. Most of the 

kera.tophyres in this area have flow structures; some 

contain rock fragments and have textures suggesting 

tuffs. The last named rocks are largely mylonitic, 

however, and shards (if they existed) have been destroyed. The conglomerate and conglomeratic sandstone contain angular to subrounded granules ~nd 

pebbles of greenstone, felsite, and quartz in a chlonteand sericite-rich matrix. Some of these rocks might 

be termed tuff-breccias or agglomerates as they contain 

pumiceous boulders of greenstone, some of which are 

probably volcanic bombs. . . 

Two types of keratophyre are recognized: potassic 

keratophyre (rare), which contains abundant phenocrysts of orthoclase and has a "glassy" groundmass, and 

sodic keratophyre, which contains albite phenocrysts 

only, and generally has a microlitic groundmass. The 

potassic keratophyre (fig. 309.3) contains phenocrysts 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293- 435 D-45 

0 1 MILLIMETER .___ ____ _J 

FIGURE 309.3.-Keratophyre or keratophyre-tuff rich in orthoclase. Many crystals of albite are partly altered to orthoclase. Secondary quartz occurs in patches (not visible in 

sketch). 

of albite in addition to orthoclase and the original 

glassy groundmass has altered to a pale green nearly 

isotropic mass of chlorite, microlites of albite, quartz, 

a fine dust of sphene, and abundant tinty crystals of 

K-feldspar. 

The sodic keratophyre (fig. 309.4) contains no 

K-feldspar as phenocrysts; staining with sodium cobaltinitrite reveals that some rocks do contain slight 

amounts of K-feldspar in the groundmass. The main 

constituents of the groundmass are sericite, albite, 

quartz, and chlorite. Epidote and sphene are abundant in some rocks. The epidote probably was formed 

during albitization of the feldspar when abundant cal0 1 MILLIMETER 

FIGURE 309.4.-Keratophyre rich in phenocrysts of albite. 

Magnetite, epidote, quartz, and chlorite occur intermixed 

and in alternating bands in the vein. Epidote crystals are 

later than the magnetite and enclose many small grains of 

magnetite. 

cium was released. Magnetite is common in tiny veinlets (fig. 309.4) as replacements in the plagioclase, 

and as crystals disseminated through the groundmass. 

Quartz content is variable in both types of keratophyre and some rocks are quartz keratophyre. The 

keratophyres are altered rocks of the rhyolite and 

andesite-dacite clans. 

Diabase.-Sills of medium-grained dark-green 

diabase weather to massive outcrops in many areas in 

the volcanic belts. The intrusive origin of the diabase 

is shown locally by chilled contacts and by the development of hornfels in adjacent tuffaceous sedimentary 

rocks. 

Plagioclase shows no preferred orientation in the 

diabase and is generally in excess of interstitial augite 

(fig. 309.5). The plagioclase in most of the diabase 

has been saussuritized and contains epidote or zoisite. 

The plagioclase ranges in composition from albite to 

Anz5 • Some diabase contains water-clear albite and 

little or no epidote or zoisite. A few rocks contain 

unaltered plagioclase remnants that are calcic-labradorite, and it seems probable that the original plagioclase in all the diabase was labradorite. In addition 

to plagioclase and augite, the diabase contains abundant actinolite, chlorite, sphene, magnetite, ilmenite, 

and pyrite. The actinolite and chlorite formed from 

the augite. 

Conclusions.-The enrichment in albite in the Mount 

Chase volcanic rocks probably was largely independent 

of low-grade regional metamorphism. This conclusion is based on the fact that some of the extrusive 

rocks (spilites) which display pillow structure, retain 

NO LITE 

0 1 MILLIMETER 

FIGURE 309.5.-Dark-green diabase. Augite is altered along 

fractur es a.nd crystal edges to pal&green actinolite and 

chlorite; needles of actinolite commonly extend into plagioclase crystals ; plagioclase is cloudy throughout; the single 

crystal of titaniferous magnetite is partly alter ed to 

leucoxene. 
D-46 GEOLOGICAL SURVEY RESEARICH 1 9 61' 

diabasic texture. The lack of preferred orientation of 

the plagioclase crystals would. be unlikely if the albite 

originated by dynamic metamorphism. 

The mineralogical similarity of the diabase to the 

denser spilites previously described suggests that the 

rocks have a common source. The diabase sills probably were intruded shortly after and possibly in some 

places simultaneously with the extrusion of basaltic 

lavas at the surface. 

REFERENCE 

Neuman, R. I..., 1960, Pre-Silurian stratigraphy in the Shin 

Pond and Stacyville quadrangles, Maine, in Short papers 

in the geological sciences: U.S. Geol. Survey Prof. Paper 

400-B, p. B166-B168. 

310. POST-CARBONIFEROUS DEFORMATION OF METAMORPHIC AND IGNEOUS ROCKS NEAR THE 

NORTHERN BOUNDARY FAULT, BOSTON BASIN, MASSACHUSETTS 

By NORMAN P. CUPPELs, Boston, Mass. 

. . 

Work done in cooperation with the Massachusetts Department of Public Works 

Sedimentary rocks of Carboniferous age in the Boston Basin are separated from igneous and metamorphic 

rocks of Paleozoic and Precambrian ( ~) age north of 

the basin by the Northern Boundary fault (fig. 310.1). 

There is some evidence that the igneous and metamorphic rocks have been thrust over the sedimentary rocks 

along the Northern Boundary fault.· Recent geologic 

mapping in the Concord quadrangle has revealed a 

fault zone of similar magnitude that may be genetically 

related to the Northern Boundary fault. The fault 

zone extends from the southwest part of the quadrangle 

northeastward for at least 25 miles; its southwest extension has not been determined. The zone is about 4 

miles from the Northern Boundary fault near Waltham 

but diverges from it north of Lexington and, when 

extended, coincides with a fault zone mapped by R. 0. 

Castle (written communication, 1960), in the Wilmington and South Groveland quadrangles. Stratigraphic 

discontinuities in the Nashoba and Marlboro formations and the Andover granite led Castle to postulate a 

fault zone that extends from the northwest corner of 

the Lexington quadrangle northeastward for 18 miles 

to the town of Groveland. In the eastern part of the 

Concord quadrangle, the fault zone is separated from 

the Northern Boundary fault by the Precambrian Marlboro formation and the Paleozoic ( ~) Salem gabbrodiorite, both of which are deformed by a series of secondary faults. · 

Within the Concord quadrangle, the newly mapped 

fault zone is best exposed in a road cut at Bloody Bluff. 

The center of the bluff is a medium-grained. diorite containing andesine plagioclase and blebs of pink microcline. On the east side of the bluff, constituent mineral 

grains of the diorite are severely deformed and altered, 

producing a light-green rock mottled red in which 

grain boundaries are very hazy. A thin section of this 

altered rock shows sericitized and deformed plagioclase, 

much epidote and calcite, and no ferromagnesian min-" 

erals. Severe shattering "of the rock has resulted in 

many closely spaced and randomly oriented fractures, 

in part coated with hematite. Two major fault planes 

35 feet apart are exposed in the outcrop ; they trend 

N. 25° E. and dip 40° to 60° NW. Subsidiary faults, 

not shown on the map, have the following attitudes: 

strike N. 55° E., dip 80° NW.; strike N. 80° E., dip 90°; 

strike E., dip 75 ° S.; and strike N. 75 o W., dip 90°. 

Rocks underlying lowlands east and west of the bluff 

are probably within the fault zone. The fault pattern 

here indicates that the east side of the zone moved north 

relative to the west side. 

Bloody Bluff is an unusually good exposure in an 

area where thoroughly ·fractured rocks are commonly 

deeply eroded and covered with glacial debris; thus, 

direct evidence of major faults is rarely observed. 

Other evidence of faulting is abundant, however, such 

as small faults that have several inches to several feet 

of displacement, excessively sharp swings in the strike 

of bedding in the Marlboro formation, offset lithologic 

units, rotation of blocks of an alaskitic granite gneiss, 

and a zone of crushed rock along the trend of the major 

fault zone. This evidence suggests the fault pattern 

shown on figure 310.1. Many sharp local changes in 

the strike of bedding (from northeast to northwest) in 

the Marlboro formation occur in the area one mile south 

of Bloody Bluff to the sharp bend in the Northern 

Boundary fault near Waltham. LaForge (1932) also 
0 

SHORT PAPERS IN THE GEOLOGI:C AND HYDROLOGIC SCIENCES, ARTICLES 293-435 

MASSACHUSETTS 

INDEX MAP 

50 MILES 

Lexington 

0 

0 

EXPLANATION 

85 

2 MILES 

-~*---~ - Fault showing dip 

Dashed where inferred; singlP. 

barbed arrow shows relative movement 

Thrust fault 

Saw-teeth on upper plate 

D..--47 

PIGURE 310.1.-Map showing faults ii:i the eastern part of the. Concord quadrangle, and a probable extension into the Lexington quadrangle, Massachusetts. Position of Northern Boundary fault after LaForge (1932). 
D-48 GEOLOGICAL SURVEY RESEARCH 19 61 

mapped similar northwesterly strikes on an extension 

of this alinement of structural anomalies in the 1\:Iarlboro formation near the Northern Boundary fault. 

The deformation which produced these fault structures 

is one of the youngest tectonic events in eastern Massachusetts because the faults displace Andover granite of 

Carboniferous age-the youngest rock cut by the fault 

zone. 

REFERENCE 

LaForge, Laurence, 1932, Geology of the Boston area, Massachusetts: U.S. Geol. Survey Bull. 839, 105 p. 

311. A .REGIONAL FAULT IN EAST-CENTRAL MASSACHUSETTS AND SOUTHERN NEW HAMPSHIRE 

By RoBERT F. NovOTNY, Boston, Mass. 

Worlc .done in cooperation with the :Massachusetts Department of Pttblic Worlcs 

Geological reconnaissance in east-central Massachusetts and southern New Hampshire, in conjtmction with 

detailed bedrock mapping of the Clinton quadrangle,. 

Massachusetts, has shown that a major fault zone extends from the Sterling quadrangle, Massachusetts, 

northward into Hollis township in the Milford quadrangle, New Hampshire. However, because outcrops 

are few, a more detailed study is necessary to trace the 

fault farther northward into New Hampshire. The 

geologic map of New Hampshire (Billings, 1955) and 

the geologic map of the Manchester quadrangle, New 

llampshire ( Sriramadas, 1955) 1 show faults and zones 

of silicified rock that could be the northeastward extension of the fault discussed here. 

The relative vertical movement on the fault shown 

on figure 311.1 was determined on the basis of the 

stratigraphic sequence found south· of the Clinton quadrangle (in the Shrewsbury quadrangle). There th~ 

Worcester formation unconformably overlies the older 

Oakdale quartzite; both formations are of Carboniferous age or older. The trace of the fault is marked 

by swamps, glacial outwash, and steep-walled stream 

vitlleys. The fault plane is not exposed; however, outcrops of both the Worcester formation and the Oakdale quartzite are sufficiently abundant and are so located as to insure a reasonable degree of accuracy in 

establishing the position of the fault. 

In the Clinton quadrangle, the fault is indicated by 

the juxtaposition of the Oakdale quartzite and the 

Worcester formation, which have noticeably divergent 

strikes and dips. In general, the Oakdale quartzite 

strikes N. 20° to 30° E. and dips 50° to 70° SE.; the 

1 Sriramadas, Aluru, 1955, Geology of the Manchester quadrangle, 

New Hampshire: Unpub. Pb. D. thesis, Harvard Univ., 1.42 p. 

Worcester formation, southeast of the fault, strikes approximately north and dips 60° to 70° W. 

In the Shirley and Townsend quadrangle, zones of 

breccia and silicified rock (fig. 311.1) mark the ft),ult 

zone. The southern breccia zone consists of Oakdale 

quartzite which has been intensely folded, faulted, and 

fragmented. Axes of recumbent drag folds strike N. 

55° E. and dip 10° NW.; the axial planes strike N. 75° 

E. and dip 10°NW. The plane of a subsidiary fault, 

which apparently .. caused the folds, strikes N. 40° E. 

and dips 25° SE.; sulfides have been introduced along 

the fault zone and %6 -inch cubes of pyrite are common. 

The entire outcrop in which the subsidary fault is exposed is limonite stained. The northern breccia zone 

(fig. 311.1) consists of Oakdale quartzite fragments 

in a very fine light gray-green to black matrix. Some 

minor silicification has also occurred in this zone. 

The zone of silicified rock and large milky quartz 

veins completely occunies a hill 1,100 f3et long and 400 

feet wide in the Shirley quadrangle (fig. 311.1). The 

silicified angular rock fragments are pale-gray Oakdale 

quartzite. A rather consistent slabby parting strikes 

N. 20° E., parallel to the orientation of the hill, and dips 

79° NW. ~ it may indicate a minor amount of movement 

after the major faulting and silicification. A single 

silicified zone in the Townsend quadrangle (fig. 311.1) 

also contains fragments of Oakdale quartzite and extensive quartz veins. This zone consists of many large 

outcrops of silicified rock found for a distance of about 

1 mile parallel to the fault. Both of the silicified zones 

mentioned are on the west side of the fault, and both 

are bordered on the mist side by steep-walled strea:m 

valleys. 

Slickensided rocks north of the Massachusetts-New 

Hampshire boundary, indicate the extension of the 
,. 

SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-49 

fu.ult. In this area rocks east of the fault strike N. 47° 

E. n.nd dip 80° N"V.; and those west of the fault strike 

N. 26° E. and dip 78° NW. 

body of Worcester formation containing the abandoned 

Worcester "coal" mine (fig. 311.1) may be bounded on 

one side by the fault. 

Throughout most of the area examined the fault 

brings the Worcester formation against the Oakdale 

qun.rtzite, as mapped by Emerson (1917, fig. 2). It 

seems possible that the fault may extend southward into 

the 'Vorcester North quadrangle and that the isolated 

REFERENCES 

Billings, l\L :r., 1955, Geologic map of New Hampshire: U.S. 

Geol. Survey. 

Emerson, B. K., 1917, Geology of Massachusetts and Rhode 

Island: U.S. Geol. Survey Bull. 597, 289 p. 

71 °45' 71 °30': 42°45'~--------------~T--------------, 

NEW HAMPSHIRE ------¥----

WORCESTER NORTH 42o

15, 

71 °45' 

0 5 

MASSACHUSETTS 

PEPPERELL 

EXPLANATION 

--Fa'iiii-- Daalud where approximately 

located. U, upthrown tri.de; 

0, downthrown tri.de 

Breccia • zones 

• Silicified zones 

Nashoba 

formation 

10 MILES 

}..,IGURE 311.1.-Generalized geologic map of part of east-central 

Massachusetts. Geology, except for Clinton quadrangle, 

modified after Emerson ( 1917). Names of topographic quadrangles shown in the lower parts of the quadrangles. 
D-50 GEOLOGICAL SURVEY RESEARCH 19 61 

312. GROUND WATER IN EOCENE ROCKS IN THE JACKSON DOME AREA, MISSISSIPPI 

By JosEPH W. LANG, Jackson, Miss. 

Work done in oovperatim with the city of Jackson, Mississippi 

The Jackson dome is a large elongate fold near the 

center of the Gulf Coastal Plain in central Mississippi. 

The dome was formed in Late Cretaceou·s time, and 

folding continued into the early T~rtiary. The depositional environment and structural history of the Jackson area and nearby parts of the Coastal Plain have 

been described by Russell (1940), Fisk (1944), J(ay 

(1951), Monroe (1954), Bornhauser (1958), and others. 

In brief, during early Tertiary time great deltaic 

masses spread out over central Mississippi and encroached upon the Gulf of Mexico for long intervals 

followed by periods of less rapid sedimentation. Delta 

building reached a peak during early Eocene, began to 

slacken during middle Eocene, and had almost ceased by 

late Eocene. Areas on the flanks of Jackson dome sank 

slowly and received relatively large amounts of sediment, but the Q.ome itself stood firm or sank relatively 

slowly, and formed a barrier to the sea as it advanced 

and retreated across the area. Lignitic beds are especially numerous in Eocene rocks on the northeastern 

side of the dome, and indicate that swampy conditions 

existed there for long periods of time. 

The Eocene rocks in the Jackson dome area are assigned, from youngest to oldest, to the Wilcox, Clai- · 

borne, and Jackson groups as follows: 

Jackson group (formations not listed). 

Claiborne group : 

Cockfield formation 

Cook Mountain formation 

Sparta sand 

Zilpha clay 

Winona sand 

Tallahatta formation 

Wilcox group (formations .not listed). 

Rocks of the Wilcox group are more than twice as thick 

· along the Mississippi River than on Jackson doll).e about 

30 miles to the east; the Claiborne group, which is about 

2,400 feet thick along· the Mississippi River, is only 

1,100 feet thick on the dome. 

Figure 312.1 indicates the location and size of the 

Jackson dome, and the source and distribution of 

ground-water supplieS in the Jackson dome area. The 

aquifers commonly encountered are sandstone in the 

upper part of the Wilcox group, and the Sparta and 

Cockfield formations in the' upper part of the Clai~ 

borne group. Shallow wells in the southern part of 

the area find water in the Oligocene sands. 

Jackson, Miss., which is on top of the dome, obtains 

its municipal water from the Pearl River, but about 12 

million gallons of ground water a day is withdrawn 

from the Eocene aquifers, mostly for st1burban public 

systems, industries, hotels, and office buildings. In addition, more than 3,000 privately owned wells in Eocene 

rocks supply domestic needs in surrounding rural areas. 

'Veils producing water from the Wilcox group are 

not shown on figure 312.1. Only a few wells have been 

ddlled to the vVilcox; the water .is soft, moderately 

mineralized, and of the sodium bicarbonate-bearing 

type. 

The influence of the Jackson dome on the thickness 

of the younger Sparta and Cockfield formations is 

shown by the isopach maps, figure 312.2. Water is 

produced fron1 the Sparta in a much smaller area than 

from the Cockfield, but the Sparta is present throughout the Jackson area and is an important potential 

source of supply. Except on the crest of the dome, the 

Sparta is too deep to be drilled economically; nevertheless, wells in the Sparta produce about 80 percent of the 

ground water in the Jackson area, and more than 75 

percent of the wells are within an S-mile radius of 

downtown Jackson .. The Sparta thickens rapidly 

southwestward across the area (fig. 312.2), but the 

places of greatest thickness do not contain thicker ov 

more extensive bodies of sand. 

The Sparta s·and consists of alternating beds of sand, 

silt, clay, and lignite. The sand is angular, micaceous, 

well sorted, fine to medium grained, and commonly 

more coarse in the lower part of the formation. Thick 

sand beds at one locality have clayey counterparts elsewhere. Variations in transmissibility (permeability 

times formation thickness) are large because of these 

looal facies changes. Some beds of more permeable 

sand are continuous fqr miles in nar(ow sinuous bands, 

and these beds probably are sand-filled channels of 

ancient streams. A belt of coarse sand on the northern 

flank of the Jackson dome offers good prospects for 

large yields of ground water from the Sparta, whereas 

a few miles farther north a belt. of clayey and lignitic 

rocks offers poor prospects. Glauconite is common in 

the formation and indicates a neritic or littoral deposi-
SHORT PAPERS IN ·THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICL:ms 293-435 D-51 

EXPLANATION 

Sources of water supply 

0 

'Forest Hill sand, Oligocene 

N 

r Q 

----------: T. 

Q ~112 

~ ~: N. 

I 

I 

I 

t11 

I 

I Q 0 :Q ~ Q fi Q 4 6 8 MILES I 

R. 5 W. 

Cockfield formation, upper middle Eocene 

• Sparta sand, middle Eocene 

-/00--..._ 

Structure contour 

Drawn on top of Coc/ifield formation. 

Contour interval 100 feet 

.'...>q, 

'-, 

\ 

---------- 3 -------- 2 

! I 

Q " Qt 

4 

I •• 

9 

8 

I ,.-., . (i -1- ,. 

' 

Q i Q 

Q 7 i (il) Q Q ~\ 

~ 6 

_____ ' ":,_ ____ , I 

~ 

0 Q \l _________ ,! ----------

3 4 R. 5 E. 

FIGURE 312.1.-Source of ground-water, Jackson area, Mississippi. 

tional environment. Amber-colored ground water, particuhtrly northeast of Jackson, indicates lignitic deposits in the sands or associated clays. 

Water from the Sparta is of a soft sodium 

bicarbonate-benring type, 1tnd the total dissolved solids 

ntnge from 166 to 744 ppm (parts per million). Color 

vn.ries according to the amount of lignite present, and 

severn.l wells have been abandoned or drilled deeper to 

avoid du.rk amber colored water. Temperature of the 

wn.ter n.verages about 80° F and a few wells yield water 

warmer than 85 ° F -the warmer waters are on the 

crest of the dome. 

The Cockfield formation is similar to the Sparta in 

lithology but the Cockfield contains finer grained sands. 

The formation is about 200 feet thick on the Jackson 

dome where it crops out at a few places; it thickens 

rapidly on the flanks of the dome and attains a thickness of 570 feet about 25 miles south west of Jackson. 

Hard water occurs at the outcrop, but base exchange 

downdip causes softening. Compared with water in the 
D-52 GEOLOGICAL SURVEY RESEARCH 19 61 

Sparta sand 

0~3 ___.6"""""'9 MILES 

FIGURE 312.2.-Isopacli maps showing influence of Jackson dome on thickness of the Cockfield and Sparta formations! 

Jackson area, Mississlippi. 

Sparta formation, the amounts of sulfate, chloride, and 

dissolved solids in the Cockfield are high. 

REFERENCES 

Bornhauser, Max, 1958, Gulf Coast tectonics : Am. Assoc. 

Petroleum Geologists Bull., v. 42, p. 339-370. 

l!'isk, H. N., 1944, Geological investigation of the alluvial valley 

of the lower Mississippi River: Mississippi River Comm., 

78 p. 

Thickness interval 100 feet. 

Grim, R. E., 1936, The Eocene sediments of Mississippi : Mississippi Geol. Survey Bull. 30, 240 p. 

Kay, Marshall, 1951, North American geosynclines: Geol. Soc. 

America Mem. 48, 143 p. 

Monroe, W. H., 1954, Geology of the Jackson area, Mississippi: 

U.S. Geol. Survey Bull. 986, 133 p. 

Russell, R. T., 1940, Quaternary history of Louisiana [abs.] : 

Geol. Soc. America Bull., v. 51, p.1228. 

313. NATURAL MOVEMENT OF GROUND WATER AT A SITE ON THE MULLICA RIVER IN THE WHARTON 

TRACT, SOUTHERN NEW JERSEY ...,· 

By S. M. LANG, Trenton, N.J. 

Work done in cooperation with the New Jersey Division of Water Policy and Supply 

The Wharton Tract, which includes about 100,000 

acres in the Pine Barrens region of southern New J ersey (fig. 313.1), was purchased by the State in 1954 for 

a water reserve to meet future water requirements in the 

Camden and Atlantic City areas. An investigation 

was begun in 1956 to determine the feasibility of developing the water resources of the tract by means of wells. 

On the basis of a reconnaissance study of the geology of 

the tract, a test site of about 15 acres was selected 2:lj2 

miles north of the village of Batsto. 

The Mullica River, which is incised rather shallowly 

into the underlying sand, crosses the test site. The 

total relief is about 10 feet between the stream bed and 

the upland areas on both sides of the river. Swampy 

areas are present on each side, the more extensive area 

being along the ea.st bank. Except during periods of 

high flow, the swampy tracts stand above river level; 

however, they are wet at all times because they are 

areas of ground-water seepage. 

A rectangular location grid was established in the test 

area and the nodes of the grid were the sites of observation wells. Except for one 8-inch well, all observation wells ~tre 114 inches in Q.iameter. 

The vVharton Tract is under lain by the Cohansey 
SHORT· PAPEtRS IN THE GEOLOGIC AND HYDROLOGIC SCIENCE'S, ARTICLES 193-435 D-53 

City \.l 

~ 

~ ~ ~ 

0 10 20 30 MILES 

FIOUJtEJ313.1.-Map of southern New .Jersey showing the locution 

of the Wharton Tract (crosshatched). 

sand of :.Miocene(?) age which has a thickne.qs at the test 

site of approximately 200 feet. The formation is water 

bearing and consists of laminae of .fine, medium, and 

coarse sand and minor amounts of clay. Cores collected 

from one test hole indicate clay at depths ranging from 

25 to 26 feet and from 82 to 88 feet below land surface; 

however, at the deeper level the clay occurs mostly in 

stringers %, - to lj2-inch thick, and as a coating on the 

sand grains. In the 8-.inch observa.tion well, clay was 

found at a depth of approximately 31 feet and again at 

a depth of 81 feet. There are also traces of clay in the 

interval 65 to 81 feet. At most sites a group of three 

wells were driUecl to different depths according· to the 

expectation that clay would be present at depths ranging 

from 25 to 30 feet and from 81 to 88 feet; a well about 

25 feet deep was drilled above the first clay layer, a 

well about 50 feet deep was clriUed between the clay 

layers, and a well about 100 feet deep below the deeper 

clay layer. It was found that the upper clay layer is 

not continuous throughout the test site and that the 

lower layer, although continuous, clips to the southeast. 

Strata to a depth of 100 feet on the upland east of the 

river, therefore, form a single thick water-table aquifer. 

The wells were developed to provide hydraulic continuity with the aquifer, and water levels were measured 

in the wells periodically to study the interconnection of 

the ground water and the river under natural c~nclitions. 

Field data indicate that each water-bearing zone has· 

a reln.tively unifor1n flow pn.ttern. Figures 313.2-

313.4 show by means of contours the shape of the 

piezometric surface on June 9, 1960, for each waterbearing zone. The comparison of water-level elevations at each site indicates vertical movement between 

the various wa.ter-bearing zones. For example, the 

elevations in the shallow wells along the western edge 

of the test site are higher than those in the medium 

a.ncl deep wells, indicating that this area is one of 

recharge from the shallow to the medium and deeper 

water-bearing zones. In the vicinity of the Mullica 

River the head relationship is reversed, indicating that 

the movement between m1its is vertically upward. 

Inasmuch as the Mullica River is an effluent stream 

(receives water from the zone of saturation), the expected pattern of movement in the adjacent aquifer 

would be essentially perpendicula.r to the stream; water 

in the shallow zone would be expected to discharge 

directly into the stream, and the water in the deeper 

zones would be ·expected to move vertically upward 

to the stream. l\1oreover, underflow in the strata beneath the stream would be expected to move in the same 

direction in which the stream is flowing, which in this 

area is south. However, the data indicate that 'the 

hydraulic continuity between the aquifer and the stream 

· is poor, a.nd that the underflow moves in a direction 

opposite to that in which the stream is flowing. 

I 

•'' 

EXPLANATION 

Swampy ground 

~FEET 

· FIGuRE 313.2.-Wharton Tract field showing location of wells 

and water level for the shallow water-bearing zone on June 

9, 1960. Contour. interval 0.2 foot; datum assumed. 
D-54 GEOLOGICAL SURVEY RESEAThCH 1961 

N 

I 

field. The lack of continuity betwen the stream and 

the water-bearing layers beneath is largely the result 

of confinement due to impervious materials in the 

stream bed and. in t.he swampy areas adjacent to the 

stream. The impervious 1naterial is mostly bog iron 

·ore produced by the precipitation of iron oxide in sand 

near the surface. 

Chemical analyses of samples of ground water show 

iron concentrations greater than 11 ppm. vVater having these high concentrations of iron n1oves upward 

"'• from the shallow ground-water body to the stream, and 

the iron is oxidized and precipitates in the near-surface 

layer of sand. It is likely. that eventually the present 

stream bed will become almost impervious and ground 

water will seek other areas for discharge. 

~--91.6 

EXPLANATION 

Swampy ground 

0 100 FEET I_____L__j 

· FIGURE 313.3.-Wharton Tract field showing location of wells 

and water level in intermediate water-bearing zone on June 

9, 1960. Contour interval 0.2 foot; datum assumed. 

Figure 313.2 indicates two areas of discharge for 

water in the shallow layer. One is the area outlined 

by the closed contour at the center of the field where 

the discharge ·is by means of vertical leakage upward 

into the stream. The second appears to be the major 

area of discharge, and is in the northern part of the 

area at about the confluence of the river and.its tributary flowing in from the west. 

Underflow in an opposite direction to that in which 

the stream is flowing is shown by the northerly sloping 

piezometric surface, illustrated by the contours, in the 

intermediate and deeper water-bearing layers (figs. 

313.3 and 313.4); the contours show ground water 

moving toward the river in the northern part of the 

l 

EXPLANATION 

~ -- Swampy ground 

~OOFEET 

FIGURE 313.4.-Wharton Tract field showing location of wells 

ana water level in deep water-bearing zone on June 9, 1960. 

Contour interval 0.2 foot; datum a·ssumed. 

... 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 2 9 3-4 3 5 D-5'5 

314. VARIATION IN TEMPERATURE OF TWO STREAMS ON LONG ISLAND, NEW YORK 

By EnwARD J. PLUHOWSKI, Mineola;N.Y. 

Work done in cooperation with Suffolk County, N.Y. 

Temperatures of different streams on Long Island 

occa~ionn.lly vn.ry widely on the same day, and significant temperature variations have been noted, also, between points along the same stream. Large groundwater inflow characterizes all streams on Long Island, 

n.nd the stream temperatures are greatly influenced by 

ground-water temperatures. ·Air temperatures also 

have an influence. Two representative streams, Sampawa.ms Creek at Babylon and Champlin Creek at 

Islip, were studie<;l to determine the relative effects of 

air and ground-water temperatures on the stream 

temperatures. 

At the Sn.mpawams Creek gaging station a 3-element 

thermograph was installed to obtain air, stream, and 

ground-"·ater tempera.tures simultaneously; at the 

Chn.mplin Creek gaging station a.· continuous recorder 

was installed to obtain stream temperature and water 

stage. Expanded scale thermometers were used to obtn.in water-temperature observations manually at other 

sites. 

·The relative size and location of ponds, amount of 

ground-water inflow, and channel slopes of both streams 

are indicated on figure 314.1. On Champlin Creek, 

pondage is confined mainly to the lower reaches with 

very 1 ittle pondage upstream from the gaging station. 

On Sn,mpa.wn,ms Creek there is one large pond and 

several smaller ones upstream from the gaging station, 

and n, large one downstream at l\1onta.uk Highway. 

Ground-water inflow, as indicated by the increase in 

mean annual discharge, is small at the heads of the 

streams but increases in the middle reaches. 

As sho"~n by .figure 314.2, the highest and lowest 

stream temperatures of both streams occur in the same 

months as the highest and lowest air temperatures, 

whereas the insulating effect of soil cover causes 

extremes of ground-water temperature to lag by about 

2 months. 

A greater total area of ponds above the Sampa warns 

Creek gage resulted in a larger variation in monthly 

wa,ter temperatures at that gage (28° F) than at the 

Champlin Creek gage (18° F). Duri.ng the summer, 

ponds raise stream temperatures by absorbing solar 

radiation, but during the winter ponds lower the stream 

temperatures by increasing the rate of heat loss from 

the stream to the colder air. 

Large ground-water inflow sharply reduces the seasonal variation of temperature along the middle reaches 

of both streams. This effect is shown by four series 

of temperature observations made on Champ~in Creek 

(fig. 314.3). These observations indicate that the variation in temperatures is less than 20° F at vValnut 

Street and at Islip Boulevard where the rate of gro~nd 

water inflow is high, and that the variation is greater 

upstream and downstream from these points. 

Variations in solar radiation during the year cause 

a greater diurnal fluctuation in stream temperature in 

the spring and summer than in the fall and winter. In 

the fall and winter, when days are short and the cloud 

cover is at a maximun1, temperature fluctuations are 

small. In the spring, when d.ays lengthen and cloudiness decreases, the greater absorption of solar energy 

produces higher daytime stream temperatures, whereas 

the ground-water is still quite cold and its inflow depresses nighttime te·mperatures. 

On a cloudy day, July 14, 1959, stream temperatures 

of Sampawams Creek at 2 of the 3 sites shown on 

figure 314.4 dropped gradually throughout the day, but 

at one site they increased slightly. On a sunny day, 

August 13, 1959, a definite warming occurred at each 

site between 8 a.m. a .. nd 3 p.m., followed by a gradual 

drop in temperature. The large variation in temperature (17°F) observed at Bay Shore Road on August 13 

was due to a sma..U shallow pond just upstream. The 

pond is small enough to have its contents completely 

replaced overnight by cool grom1d-water inflow. During daylight hours the upper layers of the pond are 

rapidly heated so that its outflow produces the sharp 

temperature rise noted on figure 314.4. 

The combination of a high rate of ground-water inflow and little or no upstream pondage tends to raise 

stream temperatures in winter and to lower them during 

the sunllller; low inflow and pondage produce the opposite effect. The diurnaJ fluctuation in stream temperature depends on the absorption of solar energy; 

however, grotlnd-water inflow tends to minimize teip.-

perature fluctuation. 
D-56 

:J 60 en 

~ 8 40 Great South Bay 

LL.. 

z Iw20 

0 

:::::> 

1-

Series of ponds 

GEOLOGICAL SURVEY RESEARCH 1 9 61 

CHAMPLIN CREEK 

STREAM PROFILE 

Source 

5 0~~--------~~--------~---------~~--------~--------~~---------L----------~--------~----~ <( 0 2 4 6 8 10 12 14 16 

:I 60 en 

~ 

l-

~ 40 LL.. 

~ 

w 20 0 

:::::> 

1-

5 0 <( 

14 

- 12 en 

810 

w 8 (.!) 

0::: 

<( 

:r: 

(.) 

en 4 

0 2 

0 

£ 

::I 

0 

::::iE 

Great South Bay 

Hawleys Lake 

0 2 

~>. 

::I~ 

·.!9 ~ 

§.~ 

::::;E:r: 

4 

ooC: ..c:. c:o UQ) "So:O:: c::::l ~~ ~c: 

(.!)VI "t:IQ) 

c:> 

~<( 

:: 

DISTANCE (THOUSANDS OF FEET) 

MEAN ANNUAL DISCHARGE 

"t:l 

c.~ ·- > -Q) VI- -::I 0 

Ill 

--:::IQ) 

-=~ 

::en ~-

..C:.+-' c_)Q) 

Q)Q) 

Q)!:; 

men 

SAMPAWAMS CREEK 

STREAM PROFILE 

Two small ponds 

6 8 10 

DISTANCE (THOUSANDS OF FEET) 

MEAN ANNUAL DISCHARGE 

Q) >. ' VI~ ·;:: := c:..c:. 

::I tiD' 

en:i 

.... Q) Q):::l 

-c: c:Q) 

::I> 

:C<( 

FIGURE 314.1.-Stream profiles and mean annual discharge at selected sites. 

14 

c: >. 

~2~ ..c:. ~~ --::~en~ .... ~ Cl.. 

Small pond 

Guggenheim 

Lake 

16 

~ 

0-o 

..c:.~ 

eno 

>,0::: 

~ 

Ill 
r 

. 

SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 

E 

90 

~ 

~ 

EXPLANATION 

Monthly mean ground-water temperature. Sampawc:ms 

CreE:k gage, January 1959 to November 1960 

Stream temperature, Sampawams Creek gage, 

January 1959 to November 1960 

Stream temperature, Champlin Creek gage, 

November 1958 to November 1960 

80 EJ Air temperature, Babylon, New York, 

January 1959 to November 1960 

B

-- Mean maximum daily temperature 

- Mean monthly temperature 

-Mean minimum daily temperature 

70~------~-------.------~--------~----~ 

~ 60 :::;) 

1-

c( 

a:: 

UJ 

0. 

:::E 

UJ 

1-

50 

~ 

40 ffj 

30 

20 .__ ______ _.__ _____ -'------L--

January February March April May June July August September October November 

D-57 

December 

FIGURE 314.2.-Variation in monthly and daily temperatures of two streams on Long Island and corresponding air and 

ground-water temperatures. 

604493 0-61--5 
D-58 GEOLOGICAL SURVEY RESEARCH 1 9 61 

85 

85r-----------------------------------------------~ 

80 

75 

70 

65 

60 

55 

o,,/ 1May 6, 1959 

.... ,, 

'0-----o~----- -----:g-"" 

March 25, 1959 . 

0 

___ • - 0 

/ 0-·-·o-·-o---· -0--- 85 

. 80 

fanuary 29, 1959 

60 

55 

Date-July 14, 1959 

Weather-overcast; some light rain 

Air temperature-Maximum 76" (2 a.m.) 

Minimum 66" (10 p.m.) 

-·-·-·- lMontaukHighway 

------- ·-·--· ·--·-·--·----- \ 

Gaging station 

---------- ----------------'\-- --------- Bay Shore Road 

EASTERN STANDARD TIME 

Date-August 13, 1959 

Weather-Mostly sunny 

Air temperature-maximum 88" (3 p.m.) 

minimum 71" (6 a.m.) 

Montauk Highway 

\ Gaging station _y·-·--.......1 

/.//'·,, ......... , ~--- / '... ' --=--- ,~'' .................. . ...... 

--- ,/< ......... "-... , ...... ..._ ------... ______ , / "' BayShoreRoad 

EASTERN STANDARD TIME 

FIGURE 314.3.-Strearn temperature of Champlin Creek in the FIGURE 314.4.-Daily temperature variations of Sampawams 

early afternoon on selected days. Creek. 

315. EFFECT OF LAKE ST. LAWRENCE ON GROUND WATER IN THE BEEKMANTOWN DOLOMITE, 

NORTHERN ST. LAWRENCE COUNTY,"NEW YORK 

By FRANK W. TRAINER and RALPH C. HEATH, Albany, N.Y. 

Work done in cooperation with the Power Authority of the State of New York and the New York Water Resottrces 

Commission 

Lake St. Lawrence, a man-made lake about midway 

between Lake Ontario and Montreal, was formed in 

1958 when the St. Lawrence River was dammed during 

construction of the St. Lawrence Power Project and 

the St. Lawrence Seaway. Filling of the lake submerged the International Rapids section of the St. 

Lawrence River, providing a power reservoir and facilitating navigation of this formerly treacherous reach 

of the stream. The rise in water level during filling of 

the lake was about 80 feet at the power dam and about 

20 feet at Waddington, some 25 miles upstream. 

Lake St. ·Lawrence is in the gently rolling lowland 

which separates the Adirondack Mountains from the 

Canadian Shield. In northern St. Lawrence . County 
r 

SHORT PAPERS IN THE GEOLOGrC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-59 

this lowland is underlain nearly everywhere by glacial 

drift-chiefly interbedded till, clay, and sand-whose 

thickness averages 60 feet. Beneath the drift lie Lower 

Paleozoic dolomite, limestone, and sandstone which rest 

on Precambrian crystalline rocks and which are part of 

the southeast limb of a structural basin whose axis is 

in Ontario. The strata dip gently northwestward, are 

gently folded, nnd are cut by a few faults. Openings 

in the sedimentary rocks are chiefly fractures; there is 

essentially no intergrain porosity. 

The upper 500 feet of bedrock in the vicinity of the 

St. Lawrence and Grass Rivers, l1ear the village of 

Massena (fig. 315.1) is Beekmantown dolomite. The 

Beekmantown consists of thin strata that have modern.tely abundn,nt cross fractures, interbedded with thick 

massive strata in which cross joints are more widely 

spaced. In effect, therefore, it consists of zones of relatively more permeable rock (the thin-bedded strata) 

alternn,ting with zones of less permeable rock. Bem~use 

fractures., are much better developed parallel to the bedding than across it, the horizontn.l permeability of the 

rock is considerably greater than the vertical permeability, and the more permeable zones are poorly connected '~ith one n.nother. Thin~bedded or closely fractlrred rock in the uppermost part of the Beekmantown 

,CONTOUR INTERVAL 20 FEET 

DATUM IS MEAN SEA LEVEL 

EXPLANATION 

455-455-26 

• 

Well cited in text 

---240-

Contour showing altitude, in feet, of 

piezometric surface in June, 1958 

..-----.... 240------

Contour showing altitude, in feet, of 

piezometric surface in April, 1959 

0 

forms an apparently continuous permeable zone in the 

entire northern part of the county. Before filling of 

the lake, replenishment of water to this uppermost 

zone was almost entirely by percolation from the overlying drift. The shape of the piezometric surface in 

the uppermost bedrock (fig. 315.1) shows that before 

July 1958 recharge was chiefly in the interstream 

tracts, where the piezometric surface rose in broad. 

mounds; flow was from these mounds, normal to the 

·piezometric contours, toward the major surface streams; 

and the ground water was discharged from the bedrock 

into the streams along which the contour lines were 

indented upstream. The piezometric surface for water 

in deeper zones is believed to have been similar. This 

pattern of flow prevailed throughout the area except 

near the village of Massena, where water moved through 

the dolomite from the St. Lawrence River to the Grass 

River. 

The effect. the filling of the lake had on ground water 

in the dolomite is shown by hydrographs for several 

wells (fig. 315.2). Seasonal fluctuations of groundwater; level follow a regular pattern : the water level is 

highest in early spring and lowest in late summer, and 

in.some years there is also a peak in late autumn. This 

pattern is attributed to the more effective replenishCONTOUR INTERVAL 10 FEET 

DATUM IS MEAN SEA LEVEL 

FIGURE 315.1.-Configuration of piezometric surface for upper part of bedrock along south side of St. Lawrence R.iver 

before filling of Lake St. Lawrence. Insert shows piezometric surface near Massena before and after filling of 

the lake. 
D-60 GEOLOGICAL SURVEY RESEAThCH 1 9 6 1 

240 

235 

" - I ~~rv 

230 

Lake St Lawrence 

225 

220 _, 

....... 215 ~ 

::'5 

en 210 

z: 205 ::'5 

:IE 

....... 200 > 0 

~ ............. 

I co 

cc 230 - ~- 225 

Well456-457-2 r ~ 

d 220 

~ 215 

~ v~ 

~ 

...... 

0 

....... 

Q 

:::::> 

..... 

5 

cc 

FIGURE 315.2.-Hydrographs for Lake St. Lawrence at a point 

about 2% miles northwest of Massena, N.Y., and for 5 wells 

that tap Beekmantown dolomite in northern St. Lawrence 

County. 

ment of ground water in the glacial drift, which supplies water to the bedrock, when evaporation and 

transpiration rates are low and when the ground is 

unfrozen, and to less effective replenishment when 

evaporation and transpiration rates are high. At well 

452-452-9, about 3 miles south of ~1assena, these fluctuations continued unchanged by the filling of the lake. 

In most of the tract between the lake and the Grass 

River, however, the filling was accompanied and followed by a sharp rise in water level (fig. 315.2). In 

some low places the piezometric surface rose above the 

hind surface, resulting in actual or potential artesian 

flow. Seasonal fluctuations in wells near the lake sjnce 

have been absent or small. Near the lake the water table 

in the drift stands near or below the piezometric sur-:-

face for the bedrock and little or no water moves from 

the drift into the bedrock; steady replenishment of 

water in the drift. from the lake prevents large seasonal 

fluctuations. Farther south the water table is higher 

than the piezometric surface, water in the drift continues to supply the bedrock, and seasonal fluctuations 

of water levels occur in the dolomite. 

The contour lines on figure 315.1 show the amount 

and areal pattern of the water-level rise after the 

filling. In the upper bedrock the rise reached the 

Grass River near Massena ; it was not observed farther 

south and probably did not occur there because that 

stream is one of the principal places of discharge from 

the bedrock. A rise in water level was observed in two 

deep wells ( 452-459-2 and 455-455-26) south of the 

Grass River; both wells penetrate lower zones in the 

dolomite that could not drain freely into the Grass 

River because of the low vertical permeability of. the 

rock. The relation between rise and distance from the 

lake in 18 weHs (fig. 315.3) suggests that the effect of 

the filling extended 6 to 8 miles from the lake. · 

In well 453-507-7 the water level has remained as 

much as 8 feet above the lake, has continued to fluctuate 

seasonally, and during the filling rose and declined 

sharply because of the loading of the confined aquifer 

(Jacob, 1939). Clearly, the permeable zone tapped· by 

the well is separated from the lake and has ·a source 

higher than the lake. The water may have come from 

higher ground near the lake in New York or in Ontario, 

but because the Grass River, about 4 miles to the south, 

·~slower than any potential place of discharge within 50 

n1iles north of the lake, it appears probable that the 

ground water in the zone tapped by the well is flowing 

from Canada into the United States beneath the St. 

Lawrence River and Lake St. Lawrence. 

~ 24 

:!!: 18 

d 

~ 

~ 12 

~ 

:::; 6 

..... 

. 

456-457-2 .--r 

. 455-455-26 

./ 

452-459-2 

.. ./ 

2 3 4 5 6 

DISTANCE FROM CENTER OF ST. LAWRENCE RIVER. ALONG PROBABLE FLOW LINES, IN MILES 

FIGURE 815.3.-Rise of water level in selected bedrock wells 

near Massena, in response to filling of Lake Ht. Lawrence. 

Numbers identify wells cited in the text. 

REFERENCE 

.Jacob, C. E., 1939, Fluctuations in artesian pressure produced 

by passing railroad trains as shown in a well on Long 

Island, New York: Am. Geophys. Union Trans., pt. 4, p. 

666-674. 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-43·5 D-61 

316. THE STOKES AND SURRY COUNTIES QUARTZITE AREA, NORTH CAROLINA-A WINDOW? 

By BRucE BRYANT and JoHN C. REED, JR., Denver, Colo. 

Quartzite forms conspicuous cliffs on Hanging Rock 

l\1ountain, Sauratown l\1ountain, and Pilot Mountain, 

which rise abruptly 1,500 feet above the gently rolling 

surface of the surrounding Piedmont Plateau in Stokes 

and Surry Counties in north-central North Carolina 

(fig. 316.1). 

Although quartzite is an unusual rock in this part of 

the Piedmont, and its occurrence here may furnish 

valuable clues to the regional structure, the area has 

received surprisingly little attention. ICerr ( 1875, p. 

1.84) assigned the quartzite to the Huronian, mainly 

been.use of its low metamorphic grade, and recognized 

t·hat :it; is surrounded by schist and gneiss of medium or 

high metamorphic grade, which he assigned to the 

upper Laurentian. l\1undorff (1948) published a 

small-scnJe reconnaissance map including part of the 

area of quartzite. His map outlines an area of "quartzite and schist" with boundaries essentially the same as 

the area of Huronian rocks shown by !{err (1875). On 

the Geologic l\1a.p of North Carolina (North Carolina 

Dept. of Conserv. and Devel., 1958) the area is mapped 

as the Kings l\1ountain group and the rocks are described as qmtrtzite, marble, conglomerate, and schist. 

The area of the IGngs Mountain group is extended 

south through Y adkin County, far beyond the area of 

Huronian rocks mapped by !{err. Stuckey and Conrad 

( 1959) describe the area briefly and state that the 

quartzite and schist contain lenses of limestone. 

During the fall of 1960 we made a reconnaissance of 

the quartzite area and were impressed with many similarities in lithology and structure between the rocks 

here and rocks in the Grandfather Mountain area 70 

miles to the southwest, where we have been mapping 

for several years. 'V e wish to thank Mr. Stephan G. 

Conrad of the North Carolina Department of Conservation and Development and l\1r. Barry Centini, 

36'30' 

36'00' 

~ 

1 

I 35'30'~ 

EXPLANATION 

Sedimentary • rocks 

Sedimentary rocks younger than 

the Chilhowee group 

Chilhowee group 

Volcanic and sedimentary rocks in 

the Slate and the Kings Mountain 

belts 

D 

Schist, gneiss, and granite rocks in 

the Inner Piedmont and Charlotte 

belts 

Sedimentary and volcanic rocks 

Schist.gneiss,and granitic rocks of 

the Blue Ridge belt, including 

some intrusive rocks of Paleozoic age 

4 7 

50 MILES -.,....-.,.-?--?A' I Thrust fault 

Teeth on upper plate; · 

queried where inferred 

Granitic gneiss in the Grandfather 

Mountain window and the Stokes 

.and Surry Counties quartzite 

area 

Froun•~ H16.1..-Generulizert geologic map of northwestern North Carolina. and adjacent parts of Virginia and Tennessee showing 

location of the Stolces unci' Surry Counties quartzite area. Modified from Geologic Map of North Carolina and other sources. 
D-62 GEOLOGICAL· SURVEY RESEARJCH 1 9 61 

graduate student at North Carolina State College, who 

conducted us on a field trip in the area, and our colleagues, A. M. White, W. C. Overstreet, and R. A; 

Laurence, who contributed data. 

The prominent cliffs on the higher hills consist of 

massive medium- to coarse-grained sericitic quartzite 

and arkosic quartzite and thin layers and partings of 

green sericite phyllite locally containing garnet. Nea:-

the base of the quartzite, a quartz-pebble conglomerate 

has been reported to occur (Kerr, 1875; Barry Centini, 

oral communication, 1960). A bed of lustrous blue 

phyllite about 100 feet thick, exposed in the area northeast of Hanging Rock Mountain, apparently overlies 

the cliff-forming quartzite and is in turn overlain by 

thinly bedded quartzite and phyllite. The quartzite 

contains detrital rutile and tourmaline, a feature that 

is characteristic of rocks of the Chilhowee group in the 

Grandfather ~Iountain area and in the Unaka belt to 

the west. 

Similarities in lithology and stratigraphic sequence 

strongly suggest that the quartzite-phyllit-e sequence in 

Stokes and Surry Counties, although of slightly higher 

metamorphic grade, is correlative with the Chilhowee 

group in the ·Grandfather Mountain window (Reed and 

Bryant, 1960). The rocks do not resemble the rocks 

of the IGngs l\iountain belt as described by Keith and 

·Sterrett (1931), Kesler (1944), and Espenshade and 

Potter ( 1960) nor do they resemble rocks of the Tallulah Falls area in Georgia, which we have examined 

briefly. 

We have found no limestone or marble in the quartzite-phyllite sequence. The marble localities described 

by Conrad ( 1960) lie well outside the quartzite area 

(fig. 316.2) and seem to belong with the medium- and 

high-grade rocks of the Inner Piedmont belt. 

The quart~ite-phyllite sequence rests on strongly 

.. lineated and foliated, but generally nonlayered, granitic biotite gneiss, and both have been metamorphosed 

at relatively low grade. Locally, tectonic slices of 

quartzite are intercalated in the gneiss. These, together 

with phyllonite (probably the "crumpled schist" mentioned by Mundorff, 1948) near the contact, suggest 

that the quartzite sequence is not everywhere in stratigraphic contact with the underlying granitic gneiss. 

Perhaps the quartzite sequence has been thrust over the 

granitic gneiss, as has been demonstrated in the Grandfather Mountain window (Bryant and Reed, 1960). 

Surrounding the quartzite-phyllite sequence and 

granitic gneiss are mica schists and layered gneisses 

containing cataclastic granitic rocks and pegmatites. 

These rocks are widespread through the Inner Piedmont, and A. M. 'Vhite has found that the nearby 

.schists and layered gneiss contain staurolite and sillimanite and are of medi urn and high metamorphic grade. 

The foliation and layering in the surrounding schist 

and gneiss of the Inner Piedmont belt form a dome, 

whereas the quartzite in the Hanging Rock area is synclinal (fig. 316.2). This was recognized by Mundorff 

( 1948) although he did not point out its structural 

significance. In the few places where the quartzite 

sequence is in contact with the surrounding schists and 

layered gneisses, quartzite units appear to terminate 

abruptly and are discordant with the foliation and layering of the surrounding rocks. 

Because of its lithologic character and structural relations, we believe that the quartzite-phyllite sequence 

of Stokes and Surry Counties is part of the Chilhowee 

group, and that the underlying granitic gneiss may be 

of early Precambrian age like the basement gneiss beneath the Chilhowee rocks in the Grandfather Mountain 

window. We suggest that the quartzite and the underlying gneiss are exposed in two windows beneath an 

overriding plate of rocks of the Inner Piedmont belt 

(fig. 316.2). Structural details in the Stokes and Surry 

Counties area are complex, and detailed geologic mapping is needed to . prove or disprove our hypothesis, · 

which, if correct, would have important implications in 

the interpretation of the structure of the Piedmont. 

REFERENCE~ 

Bryant, Bruce, and Reed, J. C., Jr., 1960, Road log of the Grandfather Mountain area, North Carolina: Carolina Geol. Soc. 

Field Trip Guidebook, 21 p. 

Conrad, S. G., 1960, Crystalline limestone of the Piedmont and 

mountain regions of North Carolina: North Carolina Dept. 

Conserv, and Devel., Mineral Resources Bull. 74, 56 p. 

Espenshade, G. H., and Potter, D. B., 1960, Kyanite, sillimanite 

and andalusite d~posits of the southeastern States: U.S. 

Geol. Survey Prof." Paper 336, 121 p. 

Keith, Arthur, and Sterrett, D. B., 1931, Description of the 

Gaffney and Kings Mountain quadrangles [South CarolinaNorth Carolina] : U.S. Geol. Survey Geol. Atlas, Folio 222, 

13 p. 

Kerr, W. C., 1875, Report of the Geological Survey of North 

Carolina, v. 1, Physical geography, vesume and economical 

geology: Raleigh, N.C., 325 p. 

Kesler, T. L., 1944, Correlation of some metamorphic rocks in 

the central Carolina Piedmont : Geol. Soc. America Bull., 

v. 55, p. 755-782. 

Mundorff, M. J., 1948, Geology and ground water in the Greensboro area, North Carolina: North Carolina Dept. Conserv. 

and Devel., Mineral Resources Bull. 55, 108 p. 

North Carolina Department of Conservation and Development, 

1958, Geologic map of North Carolina, scale 1: 500,000. 

Reed, J. C., Jr., and Bryant, Bruce, 1960, Lower Cambrian 

and late Precambrian rocks in the Grandfather Mountain 

window, North Carolina [abs.]: Washington Acad. Sci. 

Jour., v. 50, no. 7, p 3-5. 

Stuckey, J. L., and Conrad, S. G., 1959, Metasedimentary rocks 

in Stokes, Surry, Yadkin, and Forsyth Counties, North 

Carolina [abs.]: Geol. Soc. ~merica Bull., v. 70, no. 12, 

pt. 2, p. 1770. 
SHORT PAPERS IN THE GEOLOGrC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 

15 

....-

gs 

ss 

Base map from Army Map 

Service sheet NJ 17-11 

A 

80°30' 

gs 

gs 

0 

10 

->-

RURAL HALL 

'{5 

~ 30 

/ 

so 

+ + + + + 

+ + + + + + + + + + + + RS + + + + + + + + + + + +/ 

+ + .:--... -- -~---.;:C...-...%~-----

5 MILES 

Geology by Bruce Bryant 

and J. C. Reed, Jr. 

A' 

EXPLANATION 

~ .. Sedimentary ~ rocks };1-~ 

i { Qual!~~:~hyliit• } I 

G 8 gs }u~6 o::: N 

coo 

::l!W 

Gneiss and schist of medium and high metamorphic ;5 ;;;! 

grade and associated granitic and mafic rocks z ~ ~ 

}

ro 

Cataclastic granitic gneiss • ~ 

------- Contact, approximately located 

1 

k~r~ai f~u\t 1 1 

Bnrbs on downthrown side 

~--y--..­

lnferred thrust fault Teeth on upper plate 

Sheared rocks in the Brevard fault zone 

• Marble occurrence (from Conrad, 1960) 

PLANAR FEATURES AND 

LINEAR FEATURES 

Planar and linear symbols may be combined 

l'iO EB 

Strike and dip of beds Horizontal beds 

--.-70 + 

Strike and dip of cleavage Horizontal cleavage 

1'17o Strike and dip of layering in gneissic rocks 

Horizontal layering •in gneissic rocks 

--v-70· 

Strike and dip of planar structure 

Probably bedding in quartzite and' phyllite and cleavage and 

foliation in other rocks (from A. M. White, written communication, 1960; and Mundorff, 1948} 

10...._ 

Bearing and plunge 

of mineral lineation 

+-+ Horizontal mineral lineation 

/0.-..-

Plunging fold or crenulation axis 

.......... Horizontal fold or crenulation axis 

X 

Horizontal mineral lineation and horizontal fold 

axis in safle outcrop 

FIGURE 316.2.-Reconnaissance geologic map of the Stokes and Surry Counties quartzite area and 

vicinity. Based partly on interpretation of high-altitude aerial photographs. 

D-63 
D-64 GEOLOGICAL SURVEY RESEARCH 19 61 

317. HYDROLOGIC PROCESSES DILUTING AND NEUTRALIZING ACID STREAMS OF THE SWATARA CREEK 

BASIN, PENNSYLVANIA 

By E. F. McCARREN, J. W. WARK, and J. R. GEORGE, Philadelphia, Pa. 

Work done in cooperation with Pennsylvania Department of Forests and Watm·s 

A study of water quality in the Swatara Creek basin 

shows how natural processes tend to dilute and neutralize acid mine drainages and retard their effects 

downstream. 

The Swatara Creek basin of the Susquehanna River 

is the basin farthest downstream that drains acid ·Wastes 

from anthracite coal mines in Schuylkill County, Pa. 

The basin drains areas of varied geology; it lies in 

parts of the Piedmont Plateau and Valley and Ridge 

provinces of the Appalachian region (fig. 317.1). In 

the Swatara Creek basin, mining wastes come mostly 

from underground pools where acidic water is impounded in the excavations of mines which are. no 

longer worked. The rate of release of this highly 

mineralized acidic water (table 317.1) increases :when 

water levels of pools are raised by infiltrated runoff or 

seepage from other underground sources, but generally 

the rate is uniform throughout the year. Therefore. 

in Swatara Creek it is possible to observe processes ·of 

dilution and the changes in chemical composition of 

mine. overflow water and neutralization by natural 

means. 

Acidic water of Swatara Creek is first diluted where 

the Upper and Lower Little Swatara Creeks flow into 

the main stream. Although originating in Schuylkill 

County, these streams are unaffected by mine wastes and 

are low in dissolved solids-less than 50 ppm (parts per 

million). The water in these streams contains c~lcium bicarbonate and has a pH range of 6.0 to 7.Q. The 

area drained by these streams is underlain by Silurian, 

Mississipian, and Pennsylvanian sandstone, shale, and 

conglomerate. 

Jonestown is the first sampling locality where the bicarbonate ion is found most of the time. Bicarbonate 

ion concentration progressively increases downstream 

(fig. 317;2). Representative chemical composition and 

pH changes in the Swatara downstream from the headwaters are illustrated by figure 317.3. 

,-' 

} 

Coal-bearing 

formations 

----,· ----

~\ 

Sandstone 

and 

Martinsburg 

shale 

Limestone 

FIGURE 317.1-Schematic diagram of Swatara· Creek basin 

showing major regions affecting water quality. 1, acid minedrainage region ; 2, neutral region ; 3, alkaline region. 
SHORT PAPERS IN THE. GEOLOGrc: AND "HYDROLOGIC SCIENCES, ARTICLES 293-435 D-65 

TNBLm 317 . .L-Chemical analyses of water·from anthracite coal mines in Swatara Creek basin, collected June 25, 1959 

[In parts per million and equivalent parts per million) 

Good Spring Middle Creek Colket 

mine 

New Lincoln mine 

Rausch Creek 

East Franklin 

mine 

Lincoln 

mine mine mine 

ppm epm ppm epm ppm eprn ppm epm ppm epm ppm epm 

---·---·---------------1------------------·1--1----1-------·--

Constituent; 

Silica (Si 02) - - - - - - -- - -- - - - - - - - - - - - - - -- - - -- - 13 

Aluminum (Al)----------------------------- .5 0.06 

Iron (Fe)-------------------------------~-- 9. 0 

Iron (Fe) in solution when analyzed _____ -_- __ . 04 . 00 

Manganese (Mn) ___________________________ 2. 9 

Manganese (Mn) in solution when analyzed ___ 2. 7 10 

Cn.lcium (Ca.)------------------------------ 41 2.05 

MtLgnesium (Mg) ___________________________ 24 1. 97 

Sodium ( N n.) _______________________________ 2. 0 . 09 

Potassium (K)----------------------------- 1.8 . 05 

Carbonate ( c 03) - - - - - - - - - - - - - - - - - - - - - - - - - - - 0 . 00 

Bicnrbonn.te ( H C 03) - - - - - - - - - - - - - - - - - - - - - - - - 0 . 00 

Sulfate (S04) ------------------------------- 214 4. 46 

Chloride (Cl) _______ - _- _- _- _--------------- 1.2 . 03 

Fluoride (F)------------------------------- .3 . 02 

Nitrnte ( N 0 3) ___________ - _ - _ - - - - - - - - - - - - - - - .3 . 00 

Dissolved solids _________ - ___ - _- _------- -------- 332 

Hardness as (Cn.COa)--------------------------- 201 

Noncarbonate __________________________________ 201 

Specific conductn.nce (micromhos at 25°C) _________ 533 pli ___________________________________________ .3. 60 ---- C~or _________________________________________ 1 

Total acidity ns H2S04-------------------------- 59 

S~wuld active mining begin again in the basin, two 

mn.jor tributaries having neutral wnJer low in dissolved 

solids will help check the effects downstream of 

increased acidie mine wastes. The largest of these 

tributaries is Little Swatara. Creek, which joins the 

Swatara at .Jonestown. This sub-basin is underlain by 

Martinsburg shale. At Sonestown, the Little Swatara 

contains cn.lcium-bicnrbonntc water a.nd the dissolved 

sol ids determination by chemical analyses made during 

the period of study did not exceed 120 ppm. 

Quittapahilla Creek flows into the Swatara upstream 

from Valley Glen and contains predominantly alkaline 

water. The Quittapahilla is ~nderlain by limestone 

a!ld receives pumped ground water from limestone 

quarries. Although this stream is capable of neutralizing acid water, it does not perform this function at 

16 15 ---- 8. 6 ---- 17 15 

5. 6 0. 62 1.9 0. 21 ----- ---- 10 1. 11 1. 1 0. 12 

9. 2 10 5. 0 ---- 9. 6 2. 3 

1. 7 . 06 1.0 . 04 . 00 0. 00 1.3 . 05 . 02 :00 

4. 9 2. 5 72 ---- 5. 8 ----- ------ ---- 3. 0 11 1.2 . 04 73 . 03 5. 8 . 21 4. 3 16 

61 3. 04 39 1. 95 4. 9 . 24 80 3. 99 21 1. 05 

48 3. 95 31 2. 55 5. 6 . 46 56 4. 61 23 1. 89 

2. 0 . 09 1.4 . 06 1.4 . 06 1.4 . 06 1.4 . 06 

1. 5 . 04 1. 2 . 03 1.0 . 03 1.5 . 04 1.8 . 05 

0 . 00 0 . 00 0 . 00 0 • 00 0 . 00 

0 . 00 0 . 00 12 . 20 0 . 00 0 . 00 

427 8. 89 280 5. 83 27 . 56 516 10. 74 158 3. 29 

3. 2 . 06 .6 . 02 1.4 . 04 1.6 . 05 .6 . 02 

.3 . 02 .3 . 02 .2 . 01 .4 . 02 .3 . 02 

.4 . 01 .2 . 00 .3 . 00 .3 . 00 1 . 00 

671 ---- 446 ---- 62 821 ----- 252 

350 ---- 225 ---- 35 ---- 430 ----- 147 

350 ---- 225 ---- 35. 430 ----- 147 

1080 ---- 864 ---- 92 1200 ----- 400 

2. 95 ---- 2. 95 ---- 6. 1 3. 00 ----- 3. 75 ---- 1 2 ---- 2 1 2 

108 69 ---- ----- ---- 132 15 

the present time because the Swatara is diluted and 

neutralized before reaching its confluence with the 

Quittapahilla. The water in the stream is calciummagnesium-bicarbonate-sulfate bearing. The concentration of calcium and magnesium is relatively high 

because the stream drains a limestone area. Another 

stream, Spring Creek, not so highly. mineralized as the 

Quittapahilla but with characteristics for neutralizing 

acidity, flows into Swatara Creek just above Union 

deposit. ·Spring Creek is al.so located in the limestone 

belt of Lebanon County. 

The concentrations of most solutes at Middletown are 

at their highest levels during the summer months and 

during periods of low flow; regardless of flow conditions, however, the Swatara at Middletown is not 

ncidic when it flows into the Susquehanna River. 
D-66 GEOLOGICAL SURVEY RESEARCH 1 9 6 1 

400~~--L-~----~--------------~------~------~-----L--------+---------------~------------~--~ 

Z300 

0 

::J 

...J 

~ 

0:: 

UJ 

Q.. 

(J) 

1-

0:: 

~200 

100 

I 

I 

I 

Chlo~ide, fluoride, a 

I 

I 

0 10 20 CHANNEL 30 MILES 40 50 60 

FIGURE 317.2.-Composition of Swatara Creek at low base flow, October, 1959. 

Finding wa.ys to correct and prevent surface pollution ca.used by coal mining and its related operations has become increasingly important in many 

regions. The Swatara Creek study· shows that acid 

water from mines is quickly neutralized if it is 

diluted by streams that have suitable chemical 

·compositions. Diverting suitable nearby streams 

into acid streams may be an effective and relatively 

economic way to counteract coal mine effiuents in 

some a.reas. 
SHOR'l' PAPERS IN THE GEOLOGI'C AND HY.DROLOGIC SCIENCES, ARTICLES 293-435 

0 4 5 MILES 

Coal·bearing 

formations 

} 

Sandstone and 

CO!lglomerate 

' 

Martinsburg 

shale 

limestone 

1

/) Gettysburg shale 

and 

Triassic diabase 

EXPLANATION 

CATIONS ANIONS 

.AI ~Cl+F+NOa 

E8]Acid I!IHC08 

0Na+K 1!§!11 804 

• Mg Scale, in percent of epm 

~ 

FIGURJ<J 317.3.-Chemical quality of streams in Swatara Greek 

basin, July 14, 16, and 17, 1958 

D-67 
D-68 GEOLOGICAL SURVEY RESEARCH 1 g fll 

318. CORRELATION OF END MORAINES IN SOUTHERN RHODE ISLAND 

By J. P. ScHAFER, Boston, Mass. 

Work done in cooperation with the Rhode Island Development Council 

Two prominent sets of end moraines (fig. 318.1) of 

Wisconsin age extend along the coast,11l area of southern 

New England (vVoodworth and "\V"igglesworth, 1934; 

Fuller, 1914). Correlations have been generally assumed along these two sets of moraines. Both sets, 

however, are broken by Rhode Island Sound, although 

in some places submarine ridges suggest the positions 

of the moraines. 

The Charlestown moraine originally was believed to 

bend southeast across the Point Judith peninsula 

(Woodworth, 1896, p. 153; Woodworth and Marbut, 

1896, fig. 2). This bend was interpreted as an interlobate angle. Some later compilations have omitted 

this angle, and projected the Charlestown moraine directly east toward the Elizabeth Islands (for example, 

Flint, 1953, pl. 2). However, recent detailed mapping 

has shown that the Charlestown moraine at its eastern 

end grades into a broad area of ablation moraine 

(I(aye, 1960). Just to the east, the crest of the Point 

Judith peninsula constitutes a south-trending moraine, 

the Point Judith moraine (Schafer, Narragansett Pier 

quadrangle, 1961). These moraines define an interlobate angle of a little less than 90 degrees. The Point 

Judith moraine crosses the projected trend of the 

Charlestown moraine, and probably was deposited 

slightly later than the Charlestown m~raine during a 

slight re-expansion of the ice east of '£he interlobate 

angle. On Cape Cod, the Sandwich moraine overlaps 

the Buzzards Bay moraine in a similar way (Mather, 

Goldthwait, and Thiesmeyer, 1942, p. 1147). 

Recent marine-sediment studies in Rhode Island 

Sound (McMaster, 1960, fig. 12) have identified two 

belts of gravelly sediments that in some places coincide with submarine ridges, and most likely represent 

submerged moraines. A northern belt curves from the 

Point Judith moraine to the Elizabeth Islands, and a 

southern, less well defined, belt extends from Block 

Island toward Nomans Land and Martha's Vineyard. 

The northern belt is more strongly curved than the 

southern, indicating that the ice margin became more 

strongly lobate as it retreated. The absence of ridges 

along parts of these belts may be the result of filling 

of the original depressions behind the moraines with 

marine sediments. 

The ice lobe whose western edge is marked by the 

Point Judith moraine extended eastward to the interlobate angle on western Cape Cod, and is here called 

the Narragansett Bay-Buzzards Bay lobe. The southward divergence of flow within this lobe is shown by 

glacial striations and drumlins (Flint and others, 1959) 

as well as by,the moraines. The boulder fan of cumberlandite, an unusual periodotite from northern Rhode 

Island, was spread southward in the western part of 

the lobe (Shaler, 1893). 

The retreat of the ice front from the CharlestownCape Cod set of moraines was dominantly by stagnation 

zone retreat. However; the Slocum (Power, 1957) and 

Wickford (Schafer, 1961) quadrangles on the western side of Narragansett Bay contain five small moraines (locality 1, fig. 318.1). These moraines were 

built in topographically favorable places along the 

western margin of the shrinking Narragansett BayBuzzards Bay lobe, and are successively younger from 

southwest to northeast. The absence of correlat.i ve 

moraines on the west side of the interlobate angle indicates that the ice on the upland west of the Narragansett basin was thin and motionless at its margin. On 

figure 318.1, it appears that the western two of these 

moraines might correlate with the Point Judith moraine, but actually when they were being depos1ted the 

ice margin bent sharply eastward around an upland 

area, considerably north of the Point Judith moraine. 

Much additional information about positions of ice 

margins at the times of deposition of th~se moraines is 

revealed by contemporaneous ice-contact slopes of outwash deposits (not shown on figure 318.1). 

The remarkable boulder masses of Cat Rocks and 

Queens Fort are correlated (Power, 1957) with the 

two western moraines of this series. (Note that the 

names Cat Rocks and Queens Fort apply only to the 

small bodies indicated on figure 318.1.) These two 

boulder masses once were included in the Queen's River 

moraine, which was described as a generally southwesttrending moraine about 10 miles long (Woodworth and 

Marbut, 1896). However, recent mapping (Power, 

1957; T. G. Feininger, written communication, 1959) 

has shown that the Cat Rocks and Queens Fort (formerly called Queen's J(itchen) are the only morainic 
-----------

---

EXPLANATION 

Moraine 

Connection or extension of moraine 

+-+--i-TMargin of cumberlandite fan 

"") 

Area of gravelly - bottom 

materials, after McMaster, 1960 

······· Submarine ridge, sketched from U. S. Coast and Geodetic Survey charts 

CONNECTICUT 

... ~~ 

~""_/ ....,~_,· 

/.. 

ul'lD _.. -- .. D so ;_-- ···.:. Isr..A.l'l ..- _.. .. ·. ... . ..... .. ol'lG::...,...- -~ ... J..,- ~~· .. PLUM 

··:: ISLAND 

RHODE 

-,"' ' 

\ \ " -) 

I .. // 

.. ·;-:/:;) /.·· ./ I,-.\ ISLAND '- _ _..,. / 

l...-..... -SoUND/ sovl'lDl - 13r.,ocl( 

A]'JD . / \ r..~ . \ 

!S. BLOCK /. .. ·· .,, 

ISLAND : .\ 

: . · ........ \ .. · ~ 

';;:_..., I 

/ '-)-

" ./ \ ./ 

../ 

.... "" ( 

I / 

J I 

( ) '-

1) 

10 5 0 10 20 MILES 

( 

/ 

I 

/ 

I / 

'--/ 

1 ... 

MONKS 

BOR~l!,G_H.... HILL 

SNIPAT~UT '!G 

~HOOCK 

/ 

/ 

... , 

I 

-(.;\ I 0 .... ---

_.-,.NOMANS 

.··LAND 

\c 

ATLAJ'I'f. 

ocEJ\~ 

FIGURE 318.1.-End moraines in part of southern New .England: Numbers for unnamed moraines are referred to in text. 

42° 

41° 

U1 

~ 0 

~ 

~ 

> 

~ 

t:rJ 

:.:l 

Ul 

J-1 

z 

s 

t:rJ 

0 

t:rJ 

0 

t"4 

0 

0 

~ 

Q 

~ ~ 

~ ~ 

:.:l' 

0 

t"4 

0 

0 

t-,-i 

(J 

~ J-1 

t:rJ 

~ 

~ ~Ul 

> 

~ 

~ 

~ t:rJ 

Ul 

~ 

co 

C/.:1 

I 

~ 

C/.:1 

Cl1 

tj 

I 

~ 

<:0 
D-70 GEOLOGICAL SURVEY RESEARCH 1 9 61 

bodies along that line, and that the Queen's River 

moraine 'does not exist. 

Goldsmith ( 1960) has suggested that the Ledyard 

moraine in southeastern Connecticut may be correlative with some of the western members of the series of 

moraines at locality 1, figure 318.1. It is doubtful, 

however, whether minor ~oraines can be correlated 

over such a distance, and the uncertainty is even greater 

for correlation across an interlobate angJe such as 

exists between the two areas. The two small moraines 

in southeastern Connecticut (locality 2, fig. 318.1) are 

most likely slightly older than the Ledyard moraine 

(Schafer, written communication). . 

As the ice retreated northwest from the ii;Lterlobate 

angle on Cape Cod, it built moraines at several positions of that angle (Mather, 1952). . The first position 

is marked by the Ellisville and Hog Rock moraines, 

the second by the Snipatuit moraine and the possibly 

correlative small moraines in the southern part of the 

Assawompset Pond quadrangle (locality 3, fig. 318.1; 

Carl Koteff, oral communication, 1961), and the third 

by the Monks Hill and Middleborough moraines. The 

Snipatuit and Middleborough moraines are mapped as 

kame moraines (Mather, 1952), and they grade. westward into collapsed ice-contact margins of outwash. 

Thus, the two main groups of moraines north of the 

Harbor Hill-Charlestown-Cape Cod set of moraines are 

those north of the Charlestown-Point Judith interlobate angle, and those north west of the Cape Cod interlobate angle. During the early part of ice retreat, 

stagnation evidently occurred immediately on the 

. broad central parts of the lobes, but the ice remained 

active at its margin near the interlobate angles during 

the first 15 to 20 miles of retreat. 

REFERENCES 

Flint, R. F., 1953, Probable Wisconsin substages and late-Wisconsin events in northeastern United States and southeastern Canada: Geol. Soc. America Bull., v. 64, p. 897-919. 

Flint, R. F., and others, 1959, Glacial map of the United States 

east of the Rocky Mountains: Geol. Soc. America. 

Fuller, M. L., 1914, The geology of Long Island, New York: 

U.S. Geol. Survey Prof. Paper 82, 231 p. 

Goldsmith, Richard, 1960, A post-Harbor Hill-Charlestown 

moraine i:p. southeastern Connecticut: Am. Jour. Sci., v. 

258, p. 740-743. 

Kaye, C. A., 1960, Surficial geology of the Kingston quadrangle, 

Rhode Island: U.S. Geol. Survey Bull., 1071-1 [19611. 

McMaster, R. L., 1960, Sediments of Narragansett Bay system 

and Rhode Island Sound, Rhode Island: Jour. Sed. Petrology, v. 30, p. 249-274. 

Mather, K. F., 1952, Glacial geology in the Buzzards Bay. region 

and western Cape Cod-Field Trip no. 4, p. 119-142, in 

Geol. Soc. America, Guidebook for field trips in New 

England. 

Mather, K. F., Goldthwait, R. P., and Thiesmeyer, L. R., 1942, 

Pleistocene geology of western Cape Cod, Massachusetts : 

Geol. Soc. America Bull., v. 53, p. 1127-1174. 

Power, W. R., Jr., 1957, Surficial geology of the Slocum quadrangle, Rhode Island: U.S. Geol. Survey Geol. Quad. MaP. 

GQ-106. · 

Schafer, J. P., 1961, Surficial geology of the Narragansett Pier 

quadrangle, Rhode Island: U.S. Geol. Survey Geol. Quad. 

Map GQ-140. 

--, 1961, Surficial geology of the Wickford quadrangle, 

Rhode Island: U.S. Geol. Survey Geol. Quad. Map GQ-136. 

Shaler, N. S., 1893, The conditions of erosion beneath deep 

glaciers, based upon a study of the boulder train from 

Iron Hill, Cumberland, R.I. : Harvard College Mus. Comp. 

Zoology Bull. 16, p. 18&-225. 

Woodworth, J. B., 1800, Th.e retreat of tlie ice-sheet in the 

Narragansett Bay region: Am. Geologist, v. 18, p. 150:-168, 

391-392 . 

Woodworth, J. B., and Marbut, C. F., 1896, The Queen's River 

moraine in Rhode Island: Jour. Geology, v. 4, p. 691-703. 

Woodworth, .J. B., and Wigglesworth, Edward, 1934, Geography 

and geology of the region including Cape Cod, the Elizabeth Islands, Nantucket, Marthas VJneyard, Nomans Land 

and Block Island: Harvard Colle~ Mus. Comp. Zoology 

Mem., v. 52, 322 p. 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-71 

319. RESIDUAL SEA WATER IN THE BASEMENT COMPLEX OF THE FALL ZONE IN THE VICINITY OF 

FREDERICKSBURG, VIRGINIA 

By SEYMOUR SUBITZK.Y, Trenton, N.J. 

Work done in cooperation with the Commonwealth of Virgi.nia 1 

Several wells obtain water from the basement complex· crystalline rocks of the Fall Zone in the vicinity . 

of Fredericksburg, Va. Locally, the basement complex 

rocks consist of granite and granite gneiss of Paleozoic( n and Precambrian age. "Tater occurs chiefly in 

fissu~·es and joints in these rocks at depth and in a 

weathered zone directly overlying the fresh rock. 

Water obtained from .the weathered part of the basement complex varies w'idely in content of dissolved 

mineral constituents and contains objectionable 

amounts of iron, but is suitable for most domestic 

uses. I-Iowever, waters from the deeper, fractured 

zones of the basement complex have been reported to 

contain as much as 5,500 ppm (parts per million) 

chloride. 

The saline water occurring in the basement complex 

within the Fall Zone is believed to be residual sea 

water which covered the area during Tertiary time. 

This hypothesis is suggested from the occurrence of 

Eocene and Miocene marine deposits overlying 

crystalline rocks of the basement complex along the 

eastern border of the Piedmont (Clark and Miller, 

1012). Joints a;nd fissures in the crystalline rocks provided open channelways for entry of sea water either 

directly from the sea, in the area just west of the Fall 

Zone, or by percolation downward through the overlying Cretaceous rocks, in the area east of the Fall 

Zone. 

The end of Tertiary time is believed to mark the last 

marine inundation of the area. Gradually, as the Tertiary seas receded, sea water was slowly replaced by 

fresh water moving from the recharge area through 

the ground-water reservoir. By Pleistocene time the 

Fredericksburg area was mantled by nonmarine· terrn.ce deposits that locally overlie the basement complex 

and by sands of the Patuxent formation (Lower Cretaceous). Increased precipitation provided an addi1 Tbls paper Is based on work done during a Federal-State cooperative 

program that was terminated In June 1957. 

tional source of fresh water to enter the ground-water 

reservOir. 

Fresh water circulates more freely within the sands 

of the Patuxent formation and within the uppermost 

part of the crystalline rocks than in less fractured 

crystalline rocks at depth. The deep-seated fractures, 

which contain Tertiary residual sea water, therefore, 

are less slowly flushed out. An interface between fresh 

water and salt water is believed to occur in the basement complex and may possibly extend into the 

overlying Patuxent formation. 

Figure 319.1 (p. D-72) represents diagramatically 

the fresh-water circulation and the residual saline water. Wells 52, 72, 74, and 112, which penetrate the basement complex to considerable depths, ·yield water 

containing 550 to 5,500 ppm of chloride. Water in well 

54, obtained from sands of the Patuxe11-t formation, contains 112 ppm of chloride-normal concentrations in 

the Patu~ent are less than 20 ppm. Well 53, tapping a 

higher water-bearing zone within the Patuxent formation, yields water cQ.ntaining only 2.8 ppm chloride. 

Wells 57 and 78, tapping essentially the same waterbearing zone, yield water differing- considerably in 

chloride content .. This condition is believed to reflect 

the irregularity of the bedrock surface and the arrangement of the interconnecting joint systems which permit 

some mixing of residual sea water and fresh ground 

water. Well133, which penetrates 15 feet of the basement complex, yields water containing 137 ppm of 

chloride, indicating the proximity of an interface between salt and fresh water. 

Inasmuch as the total volume of water-bearing cracks 

in the basement complex is a very small percentage of 

the total volume of the rocks, it is likely that the salt 

water may be mixed with fresh water and thereby 

freshened by long-Continued pumping of wells. 

REFERENCE 

Clark, W. B., and Miller, B. L., 1912, The physiography and 

geology of the Coastal Plain province of Virginia : Virginia 

Geol. Survey Bull. 4, p. 13-222. 
~ 

400' 

300' 

200' 

100' 

SEA LEVEL 

100' 

200' 

300' 

400' 

500' 

u 

E 

c. 

c. 

N 

oi 

.... 

<:) (]_ . 

~E Eu. ~· u ~ ~ §.u ~ E 

~ ~~§.~ ~ _.NLOC.Cil 0 

~rricc)M~ g LO ~,..._,.....~ ll'i = Qi=LO_ • 

~3:~~~ ~ ... The; 3: I 

Wl 

u 

E 

c. 

c. 

0 

g 

.n 

~ 

" Qj 

3:-

Wl 

land Surface 

Sedimentary rocks (mostly the . 

Patuxent formation) 

EXPLANATION 

Movement of fresh - ground water 

Cl ----.. Movement of residual sea water 

Cl, chloride 

Wl 

Water level 

1 0 1 MILE 

400' 

300' 

200' 

100' 

SEA LEVEL 

100' 

200i 

300' 

400' 

500' 

FIGURE 319.1.-Diagrammatic section showing apparent relation of fresh ground water to residual sea water in the baseme ut complex in the Fall ~one. 

0 

I 

-....1 

tV 

0 

trl 

0 

t"4 

0 

0 

H 

·o 

> t"4 

lf1 

~ 

~ 

< ttj 

~ 

~ 

·trl 

lf1 

trl 

> 

~ 

~ 

1-4 

co 

0) 

1-4 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 2 9 3-4 3 5 D-73 

GEOLOGY AND HYDROLOGY OF WESTERN CONTERMINOUS UNITED STATES 

320. SUGGESTED MAGMATIC DIFFERENCES BETWEEN WELDED "ASH" TUFFS AND WELDED CRYSTAL 

TUFFS, ARIZONA AND NEVADA 

By RALPI-I J. RoBERTS and DoNALD W. PETERSON, Menlo Park, Calif. 

During the mapping of the Antler Peak quadrangle, 

Nevadn., in 1941-49 by Roberts, and .the I-Iaunted Canyon quadrangle, Arizona, in 1953-57 by Peterson, we 

independently recognized that welded tuffs of these 

areas are distinctly different in texture and composition 

from most welded tuffs previously described. Subsequent study has led us to believe that welded tuffs 

are o:f two principal types, welded "ash" tuffs and 

welded crystal tuffs, and that these types may be significantly related to magmatic composition and eruptive processes. Our ideas are presented here in 

preliminary form; ~dditional quantitative chemical 

and modal information is needed to test their applicn.bilit·y in this and other regions. 

We were aided in this study by the helpful criticisms of I:I. R. Cornwall and Dallas Peck, and suggestions by George C. J(ennedy, Robert R. Coats, and Paul 

C. Bateman. 

WELDED "ASH" TUFF 

'Velded "ash" tuffs are composed mainly of glass 

shards, rock fragments, and fragments of crystals that 

have been eompresscd and welded together. Few data 

on the proportions of these constitutents are available, 

but the crysta-l content is generally small. Gilbert 

(1938, p. 1834) described the Bishop tuff, near Bishop, 

Calif., which conta.ins about 10 percent crystals; Enlows ( 1955, p. 1222-1225) reported that the crystal con· 

tent of welded tuffs of the Chiricahua ~fountains, Ariz., 

generally is between 2 and 25 percent; and Mansfield 

and Ross ( 1935, p. 320) reported a few percent to a 

maximum of 25 percent crystals in welded tuff from 

southeastern Idaho. ~{arshall ( 1935, p. 331, 341, 347) 

mentioned "many crystals" in certa.in ignimbrite units 

.in New Zealand, but did not specify percentages; his 

photomicrographs show ranges in erystal content of fj 

to 25 percent. 

WELDED CRYSTAL TUFF 

"Velded ~rystal tuffs in Nevada and Arizona are 

characterized by high crystal content and fragments 

of lap ill i size in a matrix of glass shards. The crystal 

content ranges from 25 to 50 percent or more and 

suggests long-continued intratelluric crystallization 

prior to eruption. Most of these tuffs are quartz latitic 

or dac:itic in composition. 

604.493 0-61-6 

Antler Peak quadrangle, Nevada.-Welded quartz 

latite crystal tuffs from the Antler Peak quadrangle 

near the town of Battle Mountain, Nev., form extensive 

bodies as much as 300 feet thick. These include a basal 

nonwelded quartz latitic tuff that grades successively 

upward into densely welded quartz latitic vitrophyre 

a.nd aphanitic quartz latite that comprises the major 

part of the deposit (Roberts, 1951). The upper unit is 

composed of phenocrysts and relict lapilli in a matrix 

of glass shards now largely recrystallized to a cryptocrystalline aggregate (fig. 320.1). All the layers are 

similar in composition and mineralogy; textural differences due to variations in degree of welding and crystallization along strike were noted locally, but on the whole 

the layers are remarkably uniform. Phenocrysts commonly make up 35 to 50 percent of the rock in approximately the following proportions: plagioclase 33 

percent, sanidine 35 percent, quartz 22 percent, and 

biotite and accessories 10 percent. 

Globe and S1tperior, Arizona.-The· dacitic welded 

tuff sheet in the vicinity of Globe and Superior, Ariz., 

reaches a maximum thickness of about 2,000 feet. Differences in degree of welding and crystallization of 

groundmass (fig. 320.2) are similar. to those in the 

quartz latite of Antler Peak. Phenocrysts consistently 

make up 35 to 45 percent of the rock in the following 

average proportions: plagioclase 72.5 percent, sanidine 

2.5 percent, quartz 10 percent, biotite 9.2 pe;rcent, magnetite 3.4 percent, hornblende 1.9 percent, and accessories 0.5 percent. 

COMPARISON OF CHEMICAL AND MINERALOGICAL 

COMPOSITION 

A comparison of chemieal analyses of welded "ash" 

tuffs with welded crystal tuffs in the western conterminous United States reveals certain consistent 

differences. Most of the analyzed welded "ash" tuffs 

are rhyolite and have silica contents of 70. to 76 pereent, whereas the welded crystal tuffs are mostly quartz 

la.tite or dacite and have silica contents:of.62 to 72 percent. Table 320.1 shows chemical analyses of welded 

crystal tuffs (number 1 to,l4) ~tnd welded "ash" tuffs 

(number 15 to 24) fron1' · tl)e wes~ern c~nterminous 

United States. l\{odal ·,data are fragmentary, but 

crystal contei1t is given where available. 
D-74 GEOLOGICAL SURVEY RESEARCH 1961 

IliA 

FIGURE 320.1.-Typical phases of quartz latit.e, Antler Peak quadrangle, Nevada. 

I. Non welded quartz latitic lapilli tuff; lapilli show original pumiceous structure and are not defonned or compressed. A, Hand specimen. B, Photomicrograph, plane light. 

II. Quartz latitic vitrophyre. Lapilli are highly compressed and deformed, forming dense rock. A, Hand specimen. 

Fragments are argillite from underlying units. B, Photomicrograph, plane light. 

III. Aphanitic quartz latite showing pseudo-flow structure; lapilli intensely deformed and welded; show incipient 

crystallization. A, Hand specimen. B, Photomicrograph, plane light. 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-75 

"IliA 

IJA 

.•, 

·. ,, 

of' 

'fll·.· . . '. . J 

'· ' ; ' • 'I' 

I I I I I I I I I I I I I I I I I I I I ! : 

0 I 

FIGURE 320.2.-Typical phases, dacite near Globe and Superior, Ariz. 

I. Nonwelded dacitic tuff at base. Glass shards are not deformed or flattened. A, Hand specimen. B, Photomicrograph, plane light. 

II. Dacitic vitrophyre from layer between nonwelded tufl' and dacite. Glassy matrix shows extreme squeezing of 

highly welded tuff. A, Hand specimen. B, Photomicrograph, plane light. 

III. Aphanitic dacite. Groundmass is cryptocrystalline, showing flow-like structures which represent relict outlines 

of extremely flattened and devitrified lapilli. A, Hand specimen. B, Photomicrograph, plane light 
3 

TABLE 320.1-Andyses, in percent, of welded crystal tuffs and "ash" tujJs 

[Rock types and localities of numbered analyses listed on p. D-77] 

Welded crystal tuft's 

8 9 10 11 12 13 14 15 16 17 

Welded ''ash'' tuft"s 

18 19 20 21 22 23 24 

---------1---·---·---·---·---·---·---·---·---·---·---·--·---·---·---·--·---·---·---·---·---·---·----·--

8102----------------------- 70.2 71.0 70.7 71.2 70.8 71.82 71.08 69.35 70.1 68.76 71.3 64.25 61.05 72.4 75.6 76.7 76.38 74.55 73.27 75.02 74.10 75.6 

AhOs _____________________ 14.7 15.1 14.2 14.6 13.2 14.44 14.43 15.22 14.2 15.48 14.7 15.01 16.03 13.9 13.1 13.0 12.47 11.16 12.16 12.56 11.59 12.2 

Fe20s--------------------- 1.3 1.4 1.2 1.8 .93 1.50 .78 2.50 2.0 2.50 2.2 3.49 5.42 1.8 .8 .5 1.56 1.51 .74 .99 3.36 .58 

FeO _______________________ LO 1.0 .86 .56 .98 .35 .84 .38 .90 .44 .37 1.02 .98 .20 .13 .26 tr .00 .23 .00 .03 .11 

MgO______________________ .56 .62 .50 .49 .03 .34 .21 .51 .68 .56 .70 2.09 3.03 .59 .18 .13 .15 .16 .12 .13 .08 .36 

cao ______________________ 2.1 2.2 1.8 2.0 2.5 1.16 1.40 2.40 1.8 2.23 2.3 4.21 5.40 1.5 .56 .52 .15 1.53 .50 .78 .14 .54 

Na20 _____________________ 3.2 3.5 3.0 3.2 2.1 3.90 4.00 3.25 3.2 3.89 3.0 2.36 1.43 3.1 3.8 3.7 3.0 3.11 3.60 4.34 4.00 3.2 

K20----------------------- 4.6 4.3 4.8 4.4 4.4 4.88 5.44 4.48 5.1 3.88 4.4 4.07 5.58 4.5 4.8 4.5 4.85 4.66 4.77 4.74 5.54 4.4 

Ti02---------------------- .33 .33 .28 .32 .54 .61 .24 .40 .43 .50 .31 .55 .28 .11 .06 .12 .11 .14 .15 .22 .10 

P,Oa______________________ .14 .14 .11 .12 .07 .26 .09 .15 .18 .06 .01 .15 .30 .01 .01 .00 .1.11 .02 .01 .02 .02 .oo 

MoO _____________________ .04 .07 .06 .07 .01 .06 .14 .02 .06 .02 .04 .07------- .02 .04 .03 .05 .12 .09 .10 .15 .06 

H2o+ ______________________ 1.6 .49 1.9 .57 } 3.

0 { .61 .22 .67} _

64 {.57} _

98 { .s6} .~:~ 1 1.s _

35 _

34 { .26 .76 2.95 .36 .22 } 2

.

9 j{ H2o-______________________ .19 .05 . 24 .44 .34 .38 .66 . 79 1.13 .85 1.15 1.07 .18 .35 s ________ -____________________________________________________________ ------- _______ _______ _______ _______ .01 ________________________________________________________________________ _ 

BaO~---~----------------- ------- ------- ------- ------- ------- ------- ------- ------- ------- ------- ------- .07 .08 _______ ------- _______ ------- 80s. 54 ------- _______ --------------

Cl"~-----~--L.------------- ------- ------- ------- ------- ------- ------- ------- ----~-- ------- ------- ------- ------- ------- ------- ------- ------- ------- .08 ------- ------- ------- -------

73.97 73.17 

12. 7.4 13.34 

.94 1.35 

.27 . 76 

. 29 .81 

1. 04 1. 32 

3. 08 1. 80 

4. 83 7.10 

.18 ------

.03 .07 

. 04 ------

2.26 .54 

.23 

.01 

BaO .03 I .10 

F::"'--:-~-,---·: ________ "---- ------- ------- ------- ------- ------- ------- ------- ------- ____________________________ ------- ______________ ------- _______ .49 ______________ ------- -------1-----------1 C02-------~--------·--:· ____ .20 ·.04 .07 .19 ------- .01 .35 ------- .07 .14 .0& .30 ------- .05 .16 .08 ------- .04 .01 .43 .02 , ______ _ . 01 

---•---•---•---•---•---•---•---•---•---•---•---•---•---•--•---•---•----•---•---•---• I I 

TotaL ______________ 1100 100 100 100 99 99. 73 I 99. 60 I 99. 99 I 99 99.82 1100 99.64 1100. 11 1100 100 

Q _________________________ 32.7 26.7 28.1 30.8 28.7 27.5 or ________ --- ______________ 30.7 28.8 30.8 29.1 33.9 31.2 ab _________________________ 30.3 33.5 33.2 30.4 28.0 35.7 an __________________________ 6.3 11.0 7. 9 9. 7 9.4 5.6 

------------ Total. ______________ 100 100 100 100 100 100 D.I.J ______________________ 83.4 78.7 84.9 80.6 81.1 87.1 

Crystals, percent __________ 50 240-50 39 2 3o-40 2 3Q-35 2 30 

------~----

1 Differentiation index, Thornton and Tuttle (1960). 

2 Estimated. 

J Probably low: counted under binocular microscope. 

Normative values of Q, or, ab, and an recalculated to 100 percent 

25.0 29.3 27.4 27.7 33.2 27.5 22.8 35.4 34.8 

33.9 28.8 33.7 24.6 27.8 ~.4 39.0 28.6 29.3 

35.8 29.9 30.3 35.7 26.9 23.1 14. 1 28.0 33.0 

5. 3 12.0 8. 6 12.0 12.1 21.0 24.1 8.0 2.9 

------------------- 100 100 100 100 100 100 100 100 100 

90.2 81.7 82.2 88.0 82.4 68.0 64.9 86.5 94.2 

39.1 ------- 40 2 35-45 2 3Q-40 320+ ------- 2 3(}-41 5 

. ____ 

100 99.85 99. 99 I 99. 66 I 99. so I 99. 82 1100 99. 95 1100. 36 

36.1 42.0 39.0 34.9 32.2 33.1 40.4 36.4 32.8 

28.2 30.5 29.9 30.2 28.7 35.6 27.7 30.2 44.5 

33.1 26.6 28.0 32.2 38.0 31.3 28.9 27.8 16. ~ 

2. 6 .9 3.0 2. 7 1.1 ------- 3.0 5. 6 6. 7 

------------- 100 100 100 100 100 100 100 100 100 

92.4 93.8 90.4 91.5 92.1 92.1 91.6 88.9 88.7 

220 2 20-25 22()-25 8.4 5.3 14.2 16.4 212 ------

tj 

I 

-...} 

~ 

0 

l"'.l 

0 

t"l 

0 

0 

~ t"l 

r.Jl 

q 

~ 

< 

l"'.l 

~ 

~ 

l"'.l 

r.Jl 

l"'.l 

i> 

~ .... 

co 

O"l 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-77 

The relative normative values of quartz plus orthoclase, albite, and anorthite from each analysis are 

plotted on figure 320.3. The two types of welded tuff 

fuJI into two fields. The fields shown apply only to 

the Basin and Range province. Volcanic rocks of 

other magmatic provinces would have different differentiation trends, and the boundary between "ash" tuffs 

and crystal tuffs would probably be higher or lower and 

have a different slope. 

1. Vltrophyro, Rocky Canyon, Antler Peak quadrangle, Lander County, Nov. 

K. E. White, H. F. Phillips, P. W. Scott, and F. S. Borris, analysts. 

2. Quartz latlto, Rocky Canyon, Antler Peak quad,.rangle, Lander County, Nev. 

K. E. White, H. F. Phllllps, P. W. Scott, and F. S. Borris, analysts. 

3. Vltrophyrc, Elephant Head, Lander County, Nev. K. E. White, H. F. Phllllps, 

P. W. Scott, and F. S. Borris, analysts. 

4. Quartz latltc, Elephant Head, Lander County, Nev. K. E. White, H. F. 

Phillips, P. W. Scott, and F. S. Borris, analysts. 

5. Quartz latltc, ncar VIrginia City, Nev. (collected by D. E. White). L. Shapiro, 

S. M. Berthold, and E. A. Nygaard, analysts. 

6. Quartz latltc, Toyabo quartz latlte, near Unlonvllle, Nev. (collected by C. J. 

Vitallano). F. H. Ncuorbcrt, analyst. 

7. Quartz latlto, Mnrblo Falls Canyon, Paradise Peak Range, Esmeralda County, 

Nov. (collected by C. J. Vltallano). Ledoux and Co., analysts. 

8. Quartz latlto, Roberts Mountains, Nev. (Merriam and Anderson, 1942, p. 1720, 

G. Kahan, analyst). 

9. Quartz latlto, Humboldt County, Nov. (collected by C. R. Willden). P. L. D. 

Elmore, K. E. White, and S. D. ;Botts, analysts. 

IU. Dacite, ncar Globe, Ariz. (Ransome, 1903, p. 92-93, E. T. Allen, analyst). 

11. Quartz latltC', Mineral County, Nov. (collected by D. C. Ross). P. L. D. Elmore, 

S. D. Botts, and K. E. White, analysts. 

12. Noodles Range formation, ncar Cedar City, Utah, J. Hoover Mackin (written 

communication, 1960), Robert N. Ecchcr, analyst. 

13. Dacite from Swett Hills ncar Cedar City, Utah (Leith and Harder, 1908, p. 58, 

R. D. Hall, analyst). Probably equivalent to Harmony Hills t.utT of Mackin, 

1960. 

14. Rhyolite, Mineral County, Nev. (collected by D. C. Ross). P. L. D. Elmore, 

S. D. Botts, and K. E. White, analysts. 

15. Bishop tuff, Owens River Gorge, Caur., N. edge Mt. Tom quad., sec. 22, T. 5 

S., R. 31 E., white member (collected by .P. C. Bateman). P. L. D. Elmore, 

S. D. Botts, and M. D. Mack, analysts. 

11\. Bishop tuff, Owens River Gorge, Calif., N. edge Mt. Tom quad., sec. 22, T. 

5 S., R. 31 E., palo grayish purple member (collected by P. C. Bateman). 

P. L. D. Elmore, S.D. Botts, and M.D. Mack, analysts. 

17. Welded rhyolite tuff, Chlricahua National Monument, Ariz. (Enlows, 1955, 

p. 1233, Lois D. Trumbull, analyst). 

18. Welded rhyolite tuff, Chlrtcahua National Monument, Ariz. (Enlows, 1955, 

p. 1233, Lois D. Trumbull, analyst). 

ttl. Basal vltrophyro zone or welded tufT, BullCrog Hills, Beatty area, Nev., H. R. 

Cornwall (written communication, 1960). Dorothy F. Powers, analyst. 

20. Lithoidal welded tuff, Bullfrog Hills, Beatty area, Nev., H. R. Cornwall (written 

communication, 1960). Dorothy F. Powers, analyst. 

21. Lithoidal welded tuff, Oak Spring rormat.lon, Nevada Test Site, Nye County, 

Nov., H. R. Cornwall (written communication, 1960). Dorothy F. Powers, 

analyst. 

22. Welded tuff or tho Oak Spring formation, Nevada Test Site, Nye County, Nev., 

H. R. Cornwall (written communication, 191\0). Fronk Elmore, analyst. 

23. Black glass at base of Leach Canyon tuff near Three Peaks, Iron Springs County, 

Utah, J. Hoover Mackin (written communication, 1960). Robert N. Eccher, 

analyst. 

24. Trachyte from Antelope Hills, Iron Springs County, Utah (Leith and Harder, 

1908, p. 58, R. D. Hall. analyst). Probably equivalent to Bauers tuff of Mackin 

(1960). 

DIFFERENCEf$ IN MAGMATIC HISTORY AND 

ERUPTIVE BEHAVIOR 

'l'he nature of volcanic eruptions depends on composition, temperature, vohttile content, rate of vesiculation, viscocity, and other factors (Verhoogen, 1951; 

\Villiams, 1954, p. 307). Of these, volatile content and 

rate of vesiculation are probably the most important, 

for they control the violence and particle size of the 

eruption. 

The distribution of points on figure 320.3 shows that 

welded "ash" tuffs are formed from magma more silicic 

and alkalic than magma forming welded crystal tuffs. 

These two kinds of magmas may either have separate 

origins or, alternatively, may form by differentiation of 

a magma of intermediate composition. In the latter 

alternative, following emplacement of the magma in 

the upper part of the crust, plagioclase and mafic 

minerals may crystallize and settle downward; volatiles 

migrating upward would carry silica and· alkalis 

(l(ennedy, 1955, p. 494-498; Tuttle and Bowen, 1958, 

p. 90) . These two processes would tend to enrich the 

upper part of the magma in silica, alkalis, and volatiles; 

if the internal pressure finally were to exceed the confining pressure and eruption were to take place, the 

magma would be completely fragmented to yield 

typical "ash" tuff. 

The magma deeper in the chamber would have lower 

silica, alkali, and volatile content, and lower vapor 

pressure. Crystallization of the magma, together with 

accumulation of crystals settling from the upper levels, 

would proceed until crystal content would be high; if 

an eruption were to issue from this part of the magma 

chamber, crystal-rich tuff would result. Lower volatile 

content would cause less fragmentation of the material 

as it erupted, forming fewer and relatively larger particles, many in the lapilli size range. 

A simplified scheme of kind of eruption related to 

volatile content is shown in table 320.2. 

TABLE 320.2.-Effect of relative volatiLe content on the kind of 

ernption and prodnct; siliceous and 'intermediate magmas 

Volatile content. Kind or eruption 

I. Very high___ Violent initial explosion (vulcanian). 

High degree of 

fragmentation. 

II. High _______ Nuee ardente or glowing avalanche. 

Erupted magma 

continues to expand 

during transport; 

high degree of 

fragmentation. 

III. Moderate___ Similar to II, except 

that expansion is 

less, and degree of 

fragmentation is 

moderate. 

IV. Low_______ Magma erupts as 

viscous liquid. No 

fragmentation due 

to gas expansion. 

Product 

Ash, tuff, breccia 

(entirely nonwelded). 

Welded ash tuff 

(large portions of 

erupted bodies 

are non welded). 

Welded CJ:"ystal tuff 

(tops and bottoms of erupted 

bodies are nonwelded). 

Lava flows, domes, 

and spines. 
D-78 

. A. 

10 

5 

-Ab 0 

GEOLOGICAL SURVEY RESEARCH 1 9 61 

An 

~ 

0 

Oz 

Or 

An-Ab-Or-Oz 

Tetrahedron 

Welded crystal tuffs 

B . 

X 

UJ 

0 

~ 

z 

0 

~ i= 

z 

UJ 

a:: 

UJ 

..... 

..... 

0 

An 

t 

90 

80 

70 

Field of welded 

"ash" tuffs 

15 

'-17 X / 

x,, 20 21 / 

X16 X >( 19 / 

22>< 1~ X / 7 

X 2~24 / 0 

>< x'J! 10 

//,06 0 

/ 14° \ 3 / . \0 / 11 o 1 

/ 0 5\!;09 8 

4 0 \0 

0 \ 

02 \. 

Field of ' welded 

crystal tuffs 

', 

' ',, 

'',~, 

75 70 65 

..... 

0 

X 

PERCENT Si<l:! 

Oz+OrWelded "ash" tuffs 

....... , 13 

'o, 

60 

Fm~;;-320.3.-Diagram showing plotted normative values of albite ( Ab), anorthite (An), and orthoclase+quartz ( Or+Qz) 

of rocks in table 320.1 plotted on expanded section through the tetrahedron ( An-Ab-Or-Qz). Inset diagrams show (A.), 

plane of section, and (B), differentiation index (D. I.) of Thornton and Tuttle {H)60) plotted against silica. 
SHORT PAPERS IN THE GEOLOGrC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-79 

This table places the eruption of welded tuffs at 

intermediate stages in the volcanic cycle of silicic and 

intermediate lavas. 

In several regions, both crystal-rich and crystal-poor 

welded tuffs are found together, such as New Zealand 

(Marshall, 1935); Sumatra (Westerveld, 1943, 1947); 

El Salvador (Williams and Meyer-Abich, 1955) ; and 

southwestern Utah (Cook, 1957, p. 53-69; Mackin, 1960, 

p. 89-105; Williams, 1960, p. 148-152). These two 

kinds of welded tuffs may be related in origin, and may 

form parts of n. differentiation series. This may he 

tested by plotting their differentiation index (D.I. of 

Thornton and Tuttle, 1960) against silica. (See inset 

diagram on fig. 320.3.) 

Additional chemical and modal analyses are needed 

to establish regional differentiation trends and to determine the applicability of these ideas. 

REFERENCES 

Cook, E. F., 1957, Geology of the Pine Valley Mountains, Utah: 

Utah Geol. Mineralog. Survey Bull. 58, 111 p. 

Enlows, H. E., 1955, Welded tuffs of Chiricahua National Monument, Arizona: Geol. Soc. America Bull., v. 66, p. 1215-1246. 

Gilbert, C. M., 1938, Welded tuff in eastern California: Geol. 

Soc. America Bull., v. 49, p. 1829-1862. 

Kennedy, G. G., 1955, Some aspects of the role of water in rock 

melts: Geol. Soc. America Spec. Paper 62, p. 489-503. 

Lef.th, C. K., and Hard~r, E. C., 1908; The iron ores of the Iron 

Springs district, southern Utah: U.S. Geol. Survey Bull. 

338, 102 p. 

Mackin, J. H., 1960, Structural significance of Tertiary volcanic 

rock in southwestern Utah: Am. Jour. Sci., n.s., v. 258, p. 

81-131. 

Mansfield, G. R., and Ross, C. S., 1935, Welded rhyolitic tuffs 

in southeastern Idaho : Am. Geophys. Union Trans., 16th 

Ann. Meeting, pt.1, p. 308-321. 

Marshall, P., 1935, Acid rocks of the Taupo-Rotorua volcanic 

district: Royal Soc. New Zealand Trans. and Proc., v. 64, 

p. 323-366. 

Merriam, C. W., and Anderson, C. A., 1942, Reconnaissance survey of the Roberts Mountains, Nevada: Geol. Soc. America 

Bull., v. 53, p. ·1675-1727. 

Ransome, F. L., 1903, Geology of the Globe copper district, 

Arizona: U.S .. Geol. Survey Prof. Paper 12, 168 p. 

Roberts, R. J., 1951, Geology of the Antler Peak quadrangle, 

Nevada: U.S. Geol. Survey Quad. Map [GQ-10]. 

Thornton, C. P., and Tuttle, 0. F., 1960, Chemistry of igneous 

rocks, I. differentiation index: Am. Jour. Sci., n.s., v. 258," 

p. 664-684. 

Tuttle, 0. F., and Bowen, N. L., 1958, Origin of granite in the 

light of experimental studies in the system NaAlSiaO~­

KAISisOs-SiOr-ILO: Geol. Soc. America Mem. 74, 153 p. 

Verhoogen, Jean, 1951, Mechanics ·of ash formation: Am. Jour. 

Sci. n.s.,·v. 249, p. 729-739. 

Westerveld, J., 1943, ·welded rhyolitic tuffs or "ignimbrites" 

in the Pasoemah region, West Palembang, South Sumatra: 

Leidsche, Geol. Mededeel., v. 13, p. 202-217. 

--1947, On the origin of the acidic volcanic rocks around 

Lake Toba, North Sumatra: Koninkl. Nederlandse Akad. 

Wetensch. Verb. (Tweede Sectie), DL 43, no. 1, p. 152. 

Williams, Bowel, 1954, Problems and progress in volcanology : 

Quart. Jour. Geol. Soc. London, v. 109, p. 311-332. 

Williams, Bowel, and Meyer-Abich, Helmut, 1955, Volcanism 

in the southern part of El Salvador: California Univ., 

Pubs. Geol. Sci., v. 32, p. 1-64. 

Williams, P.L., 1960, A stained slice method for rapid determination of. ppenocryst composition of volcanic rocks: Am. 

Jour. Sci., n.s., v. 258, p. 148-152. 

321. EFFECTS OF A BURIED ANTICLINE ON GROUND WATER IN NAVAJO SANDSTONE IN THE COPPER 

MINE-PRESTON MESA AREA, COCONINO COUNTY, ARIZONA 

By N. E. McCLYMONns, Holbrook, Ariz. 

Work done in ooopera.tion w-ith the Bureau, of Indian Affairs a.nd thtJ Navajo Tribe 

The Copper :Mine-Preston Mesa nrea is in northcentral Arizonn. about 80 miles north of Flagstaff (fig. 

321.1). This area. was mapped as a pa.rt of the geologic 

u.nd hydrologic investigation of the N ava,jo and Hopi 

Indian Resenrations and later was studied in more 

detail for the purpose of loca.ting specific water-well 

sites. 

The rocks exposed along Echo Cliffs on the west side 

of the area include the Kaibab limestone of Permian 

age, the Moenkopi ai1d Chinle formations of Triassic 

age, the Moenave formation of Triassic ( ~) age (Harshbarger, Repenning, and Irwin, 1957), the Kayenta formation of Triassic(~) age and theN avajo sandstone of 

Triassic(~) and Jurassic age (Lewis, Irwin, and Wilson, in press), and the Carmel formation of Jurassic 

age. Younger sedimentary rocks crop out only at 

Leche-e Rock and Tsai Skizzi Rock. The Wingate 

sandstone of Triassic age is present in the subsurface 
D-80 GEOLOGICAL SURVEY RESEARCH 1 9 61 

3K-0336 

3K-3Jfio 

,l'."'··· .. ,\ 

t ................ J Preston IK-241 

Mesa 

·FIGURE 321.1.-Map of Copper Mine-Preston Mesa area, Arizona, 

showing wells, general physiographic features, and location 

of generalized sections. 

between the Moenave and Chinle in the northeast part 

of the area but wedges out to the southwest. The 

l{ayenta forms a barrier to the downward movement of 

ground water; therefore, the underlying sedimentary 

rocks have little bearing on the hydrology of the area 

and are not included on the sections (fig. 321.2). The 

Navajo is exposed throughout most of the area, except 

where it is capped by the Carmel. 

The Navajo sandstone, a massive dune deposit, is 

composed of light-red to white fine- to medium-grained 

quartz sand. It is more than 1,800 feet thick northwest 

of the area in Zion National Park (Gregory, 1950) and 

thins generally in a southeasterly direction. The 

thinning of the Navajo is presumed to be at a uniform 

rate in most areas, but an anomalous thinning is 

apparent from well logs in the Copper Mine-Preston 

Mesa area (fig. 321.3). Here the sandstone is only 

about 800 feet thick, whereas its projected thickness 

would be about 1,300 feet. This anomaly occurs on· the 

crest of an anticline in this area and indicates an increase 

in amplitude of the fold with depth. 

A widespread tongue of the Navajo sandstone 20 to 

125 feet thick occurs from 20 to 100 feet below the top 

of the underlying l{ayenta formation. This intertonguing of the l{ayenta and Navajo is important to the 

occurrence and development of ground water in this 

area. 

The major structures in the Copper Mine-PI·eston 

~1esa area are the Echo Cliffs monocline, and two synclines separated by an anticline of which the buried 

anticline is a part. The Echo Cliffs monocline is a long 

sinuous feature striking northward and dipping eastward, and having about 2,000 feet of displacement. The 

dip is as much as 16° in places. The anticlines and 

synclines east of Echo Cliffs have less displacement200 to 400 feet as estimated from surface expressionand more gentle dips of less than 3 o. The surface trace 

of the anticline as determined by measurements on the 

top of the Navajo sandstone trends north-northwest-

~vard and extends from Preston Mesa to Page; contours 

on the base of the Navajo show that at depth the crest 

is .displaced slightly to the west (fig. 321.4). Between 

Preston Mesa and a point about 6 miles northeast of 

Copper Mine the axis of this anticline is nearly flat, but 

beyond this point it plunges northward at about llf2 ° 

(figs. 321.2 and 321.4). 

Grabens and horsts,, not shown on figure 321.4, are 

prominent near the anticlinal crest east of Copper Mine 

and they occtir elsewhere. Most faults near Copper 

~1ine trend north-northwestward parallel to the trend 

of the anticline; however, some trend northeastward. 

The displacement on most faults does not exceed 50 feet. 

The origin of the buried anticline is not known, but 

presumably it was formed by differential uplift during 

or soon after deposition of theN avajo sandstone, inasmuch as underlying formations are conformable with 

the Navajo and are not thinned. An increase in the 

number of faults nea.r the crest of the anticline is probably due to tension caused by the folding. Copper minerals at Copper Mine, near the cr-est of the anticline, may 

. have been emplaced at a later time during Late Cretaceous or Tertiary magmatic activity. 

Ground water in the Navajo sandstone occurs near 

the bottom of. the formation and is under water-table 

conditions along the flanks of the buried anticline. No 

water is encountered on the higher parts of the anticline from about 5 miles southeast to about 15 miles 

north of Copper Mine. 

Recharge is effective because the Navajo sandstone, 

and sand dunes on the surface, absorb a high percentage 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-81 

6000' 

5000' 

4000' 

3000' 

6000' 

5000' 

6200' 

6000' 

5000' 

0 

A' 

EXPLANATION 

Carmel 

-

formation 

i]d 

Kayenta formation 

5 10 MILES 

l!..,IOURE 321.2.-Generalized sections of the buried anticline, A-A', southeast along crest of anticline in the vicinity of 

Page, A.ri7.., to enst side of Preston l\fesa; B-B', northeast from vicinity of Bitter Springs to Tsai Skizzi Rock; and C-C', 

northeast from the Yicinity of ~ehe Gap to Kaibito. Saturated zone in Navajo sandstone between wells is hypothetical. 

of rainfall; however, the annual rate of rainfall is only 

6.to 8 inches. The combination of low rainfall and the 

high elevation of the crest of the buried anticline relative to its flanks is unfavorable for the accumulation 

of ground water on the anticline. The faulting east of 

Copper Mine may allow water to collect in local pockets, 

but most of the faults probably would allow the water 

to escape rather than to accumulate. 

The tongues of Navajo sandstone in the upper part of 

the l{ayenta formation are important sources of ground 

water. Some wells, lT-505, for example, have been 

drilled through the main mass of the Navajo sandstone 

without obtaining appreciable quantities of water, but 

some wnter wns found in the tongue of the Navnjo 

below the tongue of the l{nyentn formation (figs. 321.1 

and 321.2, p. D-82). 

REFERENCES 

Gregory, H. E., 1950, Geology and geography of the Zion Park 

region, Utah and Arizona: U.S. Geol. Survey Prof. Paper 

220, 200 p. 

Harshbarger, J. W., Repenning, C. A., and Irwin, J. H., 1957, 

Stratigraphy of the uppermost Triassic and the Jurassic 

rocks of the Navajo country: U.S. Geol. Survey Prof. Paper 

291, 74 p. 

Lewis, G. E., Irwin, J. H., and Wilson, R. F., (in press), Changes 

in age assignments for the Glen Canyon group (Triassic 

and Jurassic) on the Colorado Plateau: Geol. Soc. America 

Bull. 
D-82 GEOLOGICAL SURVEY RESEARCH 1 9 61 

0 

FIGURE· 321.3.-Isopach map of Navajo sandstone, showing 

thinning over· buried anticline. 

111 ·oo· 

EXPLANATION 

-+--+- Anticline Syncline 

Monocline 

0 

DATUM SEA LEVEL 

FIGURE 321.4.-Map showing structure contours on base of 

Navajo sandstone. Contour interval 500 feet (long dashes) 

and 250 feet (short dashes) . Trend o·f surface structure as 

determined by measurements on the top of the Navajo superimposed to indicate relation·wit.h buried anticline. 

322. FLATTENING RATIOS OF PUMICE FRAGMENTS IN AN ASH-FLOW SHEET NEAR SUPERIOR, ARIZONA 

By DoNALD W. PETERSON, Menlo Park, Calif. 

Systematic changes in the shape of pumice fragments 

in a dacitic ash-flow sheet near Superior and Globe, 

Ariz., reflect the eruptive history and the structure of 

the sheet. Remnants of the sheet in this area (inset 

map, fig. 322.1) cover about 100 square miles; the 

sheet has a maximum thickness of about 2,000 feet 

· and an average thickness of about 500 feet. 

The pumice fragments are light gray to nearly white 

and contrast with the darker matrix, which ranges 

from reddish brown or reddish gray to light gray. 

Both the fragments and the matrix contain 35 to 45 

percent phenocrysts in the approximate proportions: 

34 plagioclase, %o quartz, lfto biotite, remainder sanidine, hornblende, magnetite, and accessories. Except 

for their lighter color, the fragments appear to be 

essentially the same rock as the matrix. Recrystallization has obliterated the original pumiceous texture of 

the fragments, and their groundmass now consists 

mainly of cryptocrystalline and microcrystaJline intergrowths of sanidine and cristobalite. Most of the 

fragments range from ~ to 4 inches in their longest 

dimension, but both larger and smaller sizes are 

common. 

In the upper part of the ash-flow sheet, pumice fragments tend to be nearly equidimensional and show little 

preferred orientation. Lower, the fragments are some-
=I ~ 1-r-lm:Jl_J_IIIIIII ~= --- =- ~I-X~~~~~,--~-~+: I I I I l : ::: 

2001 2 4 6 8 10 20 40 ;:j ~"-.... 

1

:1 EC ~-~~~ru± t 1 · ~ L:i 4001 2 4 6 8 10 20 ..... 

u.. 

~ 

w 

V) 

<( 

CD 

..... 

800 I 

E; 400 1--------1---+---f'....,_.-+-- CD 

<( 

~ 200r----_,---+--+-+--+-r~~~---r---r---_,-~r--r------~ 

z 

~ o~--J_K_~~--~-~-~~-L-L-L~---L--L--~~-L--L----~ 0 1 2 4 6 8 10 20 50 

I ::1 EO ]~li!itt~~----l-- . -I 

10001 2 4 . 6 8 10 20 

1000 r-----r---r-T~--rT~~~~~ITTTl ----1---

~ --------r--1 ~x"':~ -~ ·t~--

g1200 " 

<C -------r-- 1--x~~ ..... ---1---~ 

~800 ~ ~ - -r-r-r-----1-~-+--+-~-J_J_ 1-

<( 

~ 

§ 4001 I I I I I I I I I I I I I I I I I I I I 0:: 

a.. 

a.. 

<( 

SH 

.6 .8 1 2 4 6 8 10 20 50 90 

APPARENT FLATNESS OF PUMICE FRAGMENTS AND FLATIENING RATIOS 110"45' 

EXPLANATION 

Aj:>parent 

~t 

~ flatness equals 

length/height 

=-'7~---~-==!":' 

Range of apparent flatness 

0 

Arithmetic flattening ratio 

Arithmetic mean of apparent Rotneu 

I 

Logarithmic flattening ratio 

Mean of logarithms of apparent flatness 

95 percent confidence limits of 

logarithmic "flattening ratio 

SH 

Designation of section 

33"30' 

Dacitic 

~ ash flows 

D 

Other rocks 33 0 15' I JACl=v //C/////[ \ft I 

111 ·oo· Geology simplified from maps by 

400.----. N. P. Peterson and D. W. Peterson 

200 -·--t--

I JK 

location of sections 

where flattening 

ratios were studied 

DC 

0

1 2 4 6 8 10 20 50 100 

APPARENT FLATNESS OF PUMICE FRAGMENTS AND FLATIENING RATIOS 

FIGURE 322.1.-Relation between flattening ratio of pumice fragments and distance above the base in six measured sections. Inset map shows distribution of the ash-flow sheet near Superior, Ariz., and the location of flattening-ratio studies. 

~ 0 

::d 

1-3 

"d 

> "d 

trJ 

::d 

w 

z 

~ trJ 

0 

trJ 

0 

t'4 

0 

0 

8 

~ I::' 

~ I::' 

l:tl 

0 

t'4 

0 

0 

(':) 

9 

trJ 

~ trJ 

sn 

> 

l:tl 

=:a 

~ trJ 

[/1 

~ 

co 

C/.) 

I 

~ 

C/.) 

c.n 

~ ~ 
D-84 GEOLOGICAL SURVEY RESEAHCH 1 9 61 

what flattened and ovoid, and are oriented with their 

longer dimensions in the horizontal plane. Farther 

downward, the flattening increases until the fragments 

appear in cross sections as thin streaks and stretchedout lenses. Lower still, they may be represented by 

mere coatings on horizontal parting surfaces, and 

finally they disappear. At most outcrops individual 

fragments show a wide variation in degree of flattening, and simple statistical tests help to indicate the 

trend of flattening changes. In six different areas 

where a considerable thickness of the ash-flow sheet is 

exposed, measurement of fragments showed a systematic downward increase in flattening. 

At each outcrop chosen for study, the exposed vertical and horizontal dimensions of 30 or 40 fragments 

were measured in a plane perpendicular to the flattening. Because the plane of measurement must be perpendicular to the flattening, and because weathering 

tends either to obscure or destroy the pumice fragments, 

outcrops suitable for measurements are few and need 

to be carefully selected. In this sheet the two horizontal dimensions of most fragments are approximately 

equal, but if fragments were to show horizontal lineation, additional precautions would be required. Every 

clearly defined fragment within each selected area was 

measured in an effort to obtain a sample representative 

of fragments of all sizes, shapes, and orientations. 

The horizontal dimension divided by the vertical dimension· as measured in the outcrop is called here the 

"apparent flatness" of a fragment. The apparent flatness was determined for each fragment, and the arithmetic and logarithmic means were calculated for each 

outcrop. This mean shows the approximate amount of 

flattening at that level in the sheet, and is called the 

"flattening ratio." The arithmetic flattening ratio, 

which is the arithmetic mean of the individual apparent 

flat.nesses, is the more readily determined. The logarithmic flattening ratio, however, which is the mean 

of the logarithms of the individual apparent flatnesses, 

eliminates the abnormal influence of greatly flattened 

fragments on the mean and is a more rigorous figure. 

Both the arithmetic and logarithmic flattening ratios 

are shown on figure 322.1. 

The curves in figure 322.1 show the relation between 

the flattening ratio and the stratigraphic distance of 

each outcrop above the base of the sheet along six measured sections. The diagram also shows the range of 

the apparent flatness at each locality. Most of the 

curves slope nearly uniformly in the same direction, 

indicating a progressive and nearly uniform downward increase in the flattening. 

The logarithmic scale removes the skewness in the 

distribution of apparent flatness, and permits a test of 

the statistical validity of the sampling. The 95 percent 

confidence limits for the logarithmic flattening ratios 

·have .been calculated and are shown on the diagram. 

These confidence limits are the boundaries within which 

lie the logarithmic flattening ratios of 95 percent of 

randomly chosen groups of the same size sampled from 

this population of pumice fragments. The confidence 

limits are narrow enough to show that the procedure 

is statistically valid. During field studies the arithmetic flattening ratio is more conveniently determined, 

and because it falls near the logarithmic flattening 

ratio, within the confidence limits, errors introduced 

by using it are small. 

The most significant application of the flatteningratio study is in its bearing on the eruptive history of 

the deposit. The nearly uniform slope of most of the 

curves in figure 322.1 shows that the downward increase 

of flattening depends on the weight of the overlying 

material. Because the fragments must have been flattened before they cooled to rigidity, the uniform flattening trend indicates that the entire ash-flow sheet was 

deposited in a relatively short time. Crudely defined 

layered structures in the ash-flow sheet and a local 

reversal in flattening (fig. 322.1, curve ED) suggest 

that the material erupted in separate pulses, but the 

generally consistent flattening trend shows that the 

pulses followed one another closely enough for the 

sheet to cool as a single unit. 

The flattening ratio studies have been used for several additional purposes. In any part of the sheet that 

has been studied statistically, the flattening ratio at an 

isolated outcrop indicates its approximate stratigraphic 

distance below the original top of the sheet. The flattening ratio changes abruptly on opposite sides of 

faults, hence the curves can be used to estimate the 

stratigraphic throw. 

The slopes of the curves in figure 322.1 nearly equal 

one another and show that the downward increase in 

degree of flattening is nearly the same in different 

places in the deposit. The steepness of the slopes indicates that burial by several hundred feet of material 

was required to attain maximum flattening. 

Flattening ratio curves for pumice fragments in this 

deposit have been particularly helpful in determining 

the nature of eruptions and in recognizing faults. Possible application elsewhere will depend on the nature 

of the flattening ratio curves of individual welded tuff 

sheets .. 
SHORT PAPERS IN THE GEOLOGI'C AND HYDROLOGIC SCIENCES, ARTICLES 293-431) D-85 

323. LANDSLIDES EAST OF FUNERAL MOUNTAINS, NEAR DEATH VALLEY JUNCTION, CALIFORNIA 

By CHARLES S. DENNY, Washington, D.C. 

At their southeast end, the Funeral Mountains are 

made up of a thick sequence of easterly dipping Tertiary rocks and Paleozoic dolomite and limestone (table 

323.1), and they rise about 2,000 feet above the surrounding piedmont (fig. 323.1). Massive beds of Tertiary fanglomerate and limestone resting on shale form 

Bat Mountain. Large bodies of these massive rocks 

have slid down the precipitous mountain front and 

spread eastward onto the piedmont for distances of a 

few hundred feet to more than a mile. The slides 

northeast of Bat Mountain were first thought to be 

the much dissected remnants of an original sheet of 

breccia about a mile in diameter that came from the 

reentrant in the eastern front of the range just north of 

Bat Mountain. The total volume of these slides, however, represents only a very small part of the capacity 

of the reentrant; and detailed mapping (fig. 323.3) 

suggests that the form of the individual bodies of landslide breccia is largely an initial feature due in only a 

small way to post-slide dissection. 

Uplift of the mountains along marginal faults set 

the stage for the erosion of eli ffs on the northern and 

;:::. 

....... 

~ 

" c 

·~ 

0 

western sides of Bat Mountain. Material from these 

cliffs descended into gullies and moved out onto the 

piedmont. 

The terminal lobe of the slide south of Bat Mountain 

(fig. 323.2) is a disordered mass of fanglomerate and 

limestone blocks. The internal structure of the lobe 

portrayed in the cross sections is iargely conjectural. 

The western part of the lobe is predon1inantly fanglomerate. Near the toe, tabular masses of limestone and 

fanglomerate appear to overlap one another, and there 

is some mixture of blocks of the two rock types. In a 

very general way, however, the rocks of the slide remain in their original stratigraphic position of fanglomerate resting on limestone. The slide came down a 

narrow gully, overtopping the northeast bank, and 

spread out over the apex of the adjacent gravel fan. 

Since that time, runoff from Bat Mountain has carved 

the existing gully southwest of the lobe. 

The three landslides northeast of Bat Mountain (fig. 

323.3) consist of several digitiform plates that rest 

either on Quaternary gravel or on Oligocene(~) rocks 

stratigraphically above those comprising the plates (fig. 

EXPLANATION 

!;·. :·:~Qg ~.· ... ~1 

Gravel 

l·.·"~o~· .. ·4:1 Landslide breccia 

UNCONFORMITY 

r··· ······. ;Tc· ·····I 

Conglomerate 

l:::::::::::::::::tf:::;::::::::::J 

Fanglomerate 

W%(!$WAJ Limestone and shale 

UNCONFORMITY 

@fu@ 

Sedimentary rocks, 

undifferentiated 

Dolomite 

~ and limestone 

Contact 

u ----0- Fault 

>-

]! 0 

>-

0:: 

<( 

;::: 

0:: 

w 

Ij 

I }Ou W-

...JQ 

<N 

a. 

~ 0 Lathrop I (,~~ Wells 116" 

~~~ >-.s- < []x:Area mapped 

o"- 0~ Death ". Las Valley Jet ', Vegas 0 

f-- \ 0 ~ "~< ~t- 36"-

/.. :I'A'-:1 ~< Shoshone o~&.._ 

<~;.. I ~ "1' INDEX MAP 

U , upthrown; D, downthrown 

0 1 MILE 

Contour interval 500 feel 

FIGURE 323.1.-Generalized geologic map of eastern end of Funeral Mountains. 
D-86 GEOLOGICAL SURVEY RESEARCH 19 61 

TABLE 323.1.-Generalized section of rocks exposed in eastern end of Funeral Mountains. Based in part on work of Harald Drewes 

(written communication, 1960) 

Age Rock unit 'l'hickness (feet) Description 

--

Younger gravel 50+ Gravel, sand, and silt. 

Rubble 5+ Angular fragments of limestone mantling slides northeast of Bat Mountain 

Pleistocene and 

Recent Limestone, fanglomerate, and subordinate shale, siltstone, and sandstone 

Landslide breccia 5-200+ brecciated; source is fanglomerate unit and limestone and shale unit o 

Oligocene(?) age. 

Older gravel 5-50 Gravel and sand. 

--· ------

Conglomerate 500+ Conglomerate, subordina~e sandstone. 

Fanglomerate 100-1,500 Thick bedded, firmly cemented. 

------

Oligocene(?) Limestone, thick bedded, about 75 feet thick, overlies 75 feet or mor e 

Limestone and shale 150-·200+ of varicolored shale with subordinate siltstone, sandstone, limestone 

gypsum, and tuffaceous rocks. 

Sedimentary rocks 2, 000+ Conglomerate, shale, limestone, and fanglomerate predominate. 

undifferentiated 

Paleozoic Dolomite and 4, 500± Probably includes Perdido formation, Tin Mountain limestone, Lost Burr 0 

limestone. formation, Hidden Valley dolomite, and Ely Springs dolomite. 

323.1). The individual slides consist of 2 or 3 unconnected segments. Brecciated limestone is the dominant 

rock but the western segment of the central slide consists of \vestward-dipping blocks of both fanglomerate 

and limestone. The plates of megabreccia (Longwell, 

1951) rest on a breccia of limestone, sandstone, shale, 

and tuff, on gravel, or directly on undisturbed bedrock. 

The base of the slides is well exposed near their western 

ends, but to the east their lower slopes are mantled by 

rubble except at a few places where the rubble has 

slumped away. Contours drawn on the base of the 

slides define a surface that slopes eastward virtually 

parallel to and about 30 to 40 feet above the adjacent 

piedmont. 

The landslides northeast of Bat Mountain came from 

massive limestone and fanglomerate strata that were 

uplifted relative to the piedmont to the east along a 

high-angle fault that passes beneath two of the slides. 

Fault movement set the stage for the erosion of steep 

slopes on these massive, eastward dipping beds. The 

individual tongues are discrete slides that moved down 

shallow gullies on the piedmont, carved partly in bedrock and partly in gravel. Subsequent erosion has left 

the slides standing considerably above their surroundings. For example, the central slide bends northward 

where it rests on bedrock, then eastward, presumably 

following a shallow gully that ended where the slide 

spreads out into several fingers. At this place the slide 

probably rests on gravel. Gravel is exposed beneath 

the southern slide and this gravel contains a much 

smaller number of pebbles of Oligocene ( ~) limestone 

than does the younger gravel on the piedmont. Contours drawn on the restored base of the slide suggest 

that the landslide breccia near the western end of the 

central slide mantles a bedrock ridge, although inaccuracies of the topographic base make this interpretation uncertain. 

The estimated· volumes of these slides range individually from about lh to 2 million cubic yards. The. 

volumes of limestone and fanglomerate that could have 

been removed from two possible source areas are adequate to account for the slides; these volumes are estimated at about 3 million cubic yards for area W (fig. 

323.3) and at least 11 million cubic yards for area X. 

The age of the landslides east of the Funeral ~1ountains is unknown. The amount of post-slide erosion 

indicates that some of them are at least several thousand 

y~ars old. The form and location of the central slide 

of those northeast of Bat Mountain suggest that it is 

younger than its neighbors. It is presumed to have 

come down a gully that originated near area W (fig. 

323.3). The southern slide could have come down an 

earlier gully that passed through the southern part 

of area X. Perhaps the landslides are Pleistocene deposits, the product of more active erosion during that 

epoch. On the other hand, the sporadic cloudbursts 
1000 

SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 

0 1000 

Contour interval 40 feet 

Mapped by C. S. Denny 

and J. P. D'Agostino 

2000 3000 FEET 

i{ ... 

0 

EXPLANATION 

Younger gravel 

Landslide breccia 

Qf, fanglomerate 

Ql, limestone 

Qs, shale 

Older gravel 

Fanglomerate, subordinate 

conglomerate 

~----"' 

Contact 

Dashed where approximately located 

l!"'IOURE 323.2.-Geologic map and sections of terminal lobe of landslide south of Bat Mountain. 

D-87 

>-

0::: 

<( 

z 

0::: 

UJ 

1-

<( 

::::> 

0 
Slides mapped by C. S. Denny and H. F. Barnett 

Bedrock mapped by Harald Drewes 

1000 0 1000 2000 FEET 

'"'''""' I I 

Contour interval 40 teet, changing to 200 teet above 2800 foot contour Outline of possible source area 

Letter indicates area referred 

to in text 

~ ~ 

1 

~ 0 

~ 

~ 

f.~ .. : :.~.~.~~:Qg~·= .::-.~:n [\/ ) ~}i~9r • . c <I 

Younger gravel Rubble 

1".: Ql ~ 4]: ~ Qt'::i 

Landslide breccia 

Ql, limestone; Qf, conspicuous masses 

of fanglomerate, or mixtures of 

limestone and fanglomerate 

QS:ii~ii!.~i~!'PX?t/1 

Older gravel 

>-

0:: 

< 

z 

0:: 

L!J 

I-

< 

:::J 

0 

,.----....__,.,..,.,. .,.,..--...._22~ 

Contact 

;:::. 

~ 

~ 

.§. 

0 

Dashed where approximately located 

Restored contours on base of 

slide, interval 40 feet 

FIGURE 323.3.-Geologic map of landslides northeast of Bat Mountain. 

r::::::::::::::::::::::::t{:::::::::::::::::::::::::::::j 

Fanglomerate 

~a@]~ Limestone and shale 

Sedimentary 

~!~ rocks, undifferentiated 

Dolomite 

~ and limestone 

---~ 0 

Fault, location approximate 

>-

0:: 

< 

i= 

0:: 

L!J 

Iu 

}~ ex: 

a.. 

U, upthrown side; D, downthrown side 

0 

~ 00 

!:;':) 

t:zj 

0 

t" 

0 

0 

~ t" 

[f) 

c:1 

~ 

<: 

t:zj 

~ 

~ 

t:zj 

U1 

t:zj 

> :l:J 

~ 

.... 

~ 

C1) 
SHORT PAPERS IN THE GEOLOGrC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-89 

of the present day may in time so erode the Bat :Mountain cliffs that some infrequent catastrophic ra.in or 

earthquake will trigger a new slide. Large bodies of 

rock, for example, could be dislodged from the northwest-facing cliff on the south ~ide of area vV (fig. 

323.3), descend to its base, and move as a landslide 

northeashnu:d down the gulch and out onto the piedmont. Thus, the landslides may be the result of recurrent mountain uplift and sporadic erosion throughout the Quaternary period. 

REFERENCE 

I.Jongwell, C. H., 1951, Megabreccia developed downslope from 

large faults: Am. Jour. Sci., v. 249, p. 343-355. 

324. COMPACTION OF MONTMORILLONITE-RICH SEDIMENTS IN WESTERN FRESNO COUNTY, CALIFORNIA 

By RoBERT H. MEADE, Menlo Park, Calif. 

Several bodies of sediment are presently undergoing 

compaction in the San Joaquin Valley of California. 

This compaction is greatest. in western Fresno County 

(fig. 324.1), where it is reflected by sinking of the land 

stn·face. The sediments here consist of unconsolidated 

to semiconsolidated water-bearing sand, silt, and clay 

that were deposited on alluvial fans, flood plains, or in 

fresh-water lakes during ]ate Pliocene to Recent time. 

Their thickness ranges from about 1,000 feet in the 

northwestern part of the county to about 3,000 feet in 

the '"southern part. ~fore complete descriptions are 

given by Davis and Poland (1957, p. 420-426) and the 

Inter-Agency Committee (1958, p. 116-138). 

The present article treats the compaction of the finest 

gra.ined of these sediments, those that fall into Shepard's ( 1D54, p. 157) size categories of clay, silty clay, 

and clayey silt. The fine-grained sediments are particularly rich in montmorillonite, most of them containing between 20 and 50 percent. Other clay 

minerals, illite, chlorite, a kaolin-type mineral, and 

rnixed illite-montmorillonite, are present in subsidiary 

amounts. The principal nonclay minerals are quartz, 

feldspn.r, micaceous minerals, and hornblende. 

As in previous studies of the compaction of clayey 

sediments (summarized and discussed by von Engellmrclt, 1960, p. R5-49), progressive reduct.ion of porosity 

is taken as a measure of progressive compaction. 

Porosities of sediments from core holes (locations shown 

on figure 324.1) are plotted against deptJ1 on figure 

824.2. Although the change is small, the data indicate 

an average reduction in porosity on the order of that 

observed nt similar depths in Germany, Italy, and 

Venezuela (von Engelhardt, 1960, p. 39, 41). 

EXPULSION OF WATER. 

The principal means of compaction has been the 

expulsion of water-first the free pore water and later 

604493 0-61--7 

the water adsorbed by clay particles. Table 324.1 

shoW's the vai·iation with depth of the esti~na.ted relative amounts of pore water and adsorbed water in the 

N 

l 

.14/13-11 

1so6 feet 

.16115-34 

2007 feet 

0 10 MILES 

E'IGURE 324.1.-Area of westen1 I!...,resno County. Calif., in which 

unconsolidated to semiconsolidatecl late Cenozoic sediments 

are being compac~ed. Core boles from which the sediments 

were sampled are marked by dark ci:rcles. Holes were drilled 

hy the Inter-Agency Committee on Land Subsidence iu. the 

San .Joaquin Valley, and are designated by township-rangesection (1\:lt. Diablo base line and meridian). Depths of 

core holes given in feet helow land surface. Shading marks 

northeastern edge of deforme drocli:s of Coast Ranges. 
D-90 GEOLOGICAL SURVEY RESEARCH 19 61 

POROSITY VOLUME. IN PERCENT 

30 40 50 40 50 .... ....., 0 +--_ _...._ __ ...____ 0 ,..----'---.....__- ....., 

.... 

::z: 

~ 1500 c 

• 

14/13-11 16115-34 

• 

r= -0.4 

2000 

0 

40 50 

19117-22 

FIGURE 324.2.-Relation between porosity and depth of burial of 

clayey sediments from core holes 14/13--11, 16/15-34, and 

19/17-22. Regression lines computed by least squares 

( r = correlation coefficient), assuming arithmetic correlation. 

Actual correlation probably is semilogarithmic, but the 

short segments of semilogarithmic curves represented here 

probably approach straight lines closely enough that the assumption has not introduced serious error. Porosities of 

Corcoran clay member of the Tulare formation (a freshwater lake deposit, cross hatched) not included in computation for core hole 14/13-11. 

sediments in core hole 16/15-34. Above a depth of 

about 1,000 feet, most of the water being squeezed out 

of the clayey sediments is probably pore water. Below 

that depth, most of the water in the sediments is 

adsorbed by the clay particles, and its removal requires 

compacting pressure to overcome the physiochemical 

attraction between the water and the clay particles. 

The greater amount of sodium adsorbed by the more 

deeply buried clays also contributes to the lack of pore 

water below depths of about 1,000 feet. With all other 

TABLE 324.1.-Estimated proportions of pore water and adsorbi!d 

water in montmorillonite-rich sediments from below the water 

table in core hole 16/15-31,., and data from which estim.ates were 

derwed 

~-.!. <ll ... Thickness, In - Exchange :»Q) angstrom units, <ll 

~'g "' .. "0 ..,rn -u; of water layer 

~ cations 2 

~=Po~ 5-S adsorbed by - (percentage 

...... ~s montmorillonite 

= 0 s~ equivalents) land ss 'g£,... on- ~ t' ·- 0 surface ;; ~'Og ... ·r;: !:l<ll 

(feet) 5 o-

"' ::::o 

ec; ....... .a"Q.§ Sodi- Calcium- tD ·;:::= Calef8.£"Q "'~"0 urn-sat- and mag- t' Q 

s~ um Sodi- ...... ~ urated nesium- l c= plus e~s ~5.9 ·a ~8. urn surfaces saturated 0 8. ~'-' magne- ~ !:: surfaces ~ 00 slum 

----------------------

419 50 50 80 10 47 2.66 25 95 5 

571 55 45 80 10 54 2.68 30 96 4 

902 20 so 80 10 41 2.63 35 96 4 

1, 238 0 100 70 10 40 2. 75 20 81 19 

1, 631 0 100 25 10 44 2.69 35 64 36 

1, 953 0 100 70 10 42 2.50 25 68 32 

' Determined In the Hydrologic Laboratory of the Geological Survey. 1 Determined In the Sedimentary Petrology Laboratory of the Geological Survey 

by H. C. Starkey. 

factors (including total water content) remaining 

equal, an increase in adsorbed sodium increases the 

amount of adsorbed water and decreases the amount of 

free pore water. If calcium and magnesium were the 

only cations adsorbed by the clays, the porosity of the 

sediments probably would decrease more rapidly with 

increasing depth (Bolt, 1956, p. 91; Warkentin and 

others, 1957), and pore water probably would persist 

to depths a few hundred feet below its present limit. 

Thus, a downward increase in both compacting pressure and adsorbed sodium accounts for the apparent 

elimination of pore water below depths of about 1,000 

feet. 

Although table 324.1 gives an accurate impression of 

the state of the water in these sediments, the figures 

given in columns 2, 3, and 4 are only estimates because 

some of the data from which they were derived are 

approximate. Also, several assumptions were made, 

the principal ones of which are listed below with references to supporting data. 

1. Porosity equals total water content. 

2. Montmorillonite is the important mineral in these sediments 

that adsorbs water. (The other clay minerals certainly 

adsorb water, but considerably less than montmorillonite.) 

3. The specific surface of montmorillinite is 600m2 per g (Bower 

and Goertzen, 1959 ; Diamond and Kinter, 1958 ; Kinter and 

Diamond, 1960). (This is a minimum value; other 

authors have assumed values as large as 800 m, per g.) 

4. The sodium and the divalent cations are concentrated on 

different surfaces rather than being associated at random 

with each other on· all surfaces (Grim, 1958, p. 20). 

5. Montmorillonite, when saturated with calciwn and magnesium, ·.will attract strongly any water within 10 A (angstroms) of its surface; when saturated with sodium, it will 

attract water (less strongly than when saturated with calcium and magnesium) within at least 80 A of its surface 

(Grim, 1958, p. 20; Low, 1958, p. 61; Lutz and Kemper, 

1959, p. 89) . 

6. Montmorillonite flakes are parallel to one another and no 

effective contact exists between solid particles. This 

a~sumpti<?n, although necessary t~ the computations, is 

untrue. Figur~ 324.3 shows that the montmorillonite particles are oriented at random with respect to' one another. 

Where most of the pore water has been removed, some 

probably remains within "cellular'' enclosures formed by 

the random arrangement of particles (Kemper, 1958). 

The error introduced by this assumption is largely compensated by the errors introduced in assumptions 2 and 3. 

ORIENTATIO~ OF MONTMORILLONITE PARTICLES 

Other studies of compacted clays show that particles 

of illite and kaolinite tend to develop preferred orientation of their basal planes normal to compacting pressures of 2 kg/cm2 or less (Buessem and Na.gy, 1954; 

Mitchell, 1956). Under the compacting pressures existing in the first 2,000 feet below the surface in western Fresno County (up to about 60 kg/cm2 ), however, 
SHORT PAPERS IN THE GEOLOGrC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-91 

particles of montmorillonite have not developed preferred orientation (fig. 324.3) . 

Ignoring for the moment the preferred orientation 

in the Corcoran clay member of the Tulare formation, 

there is no indication of a progressive orientation of 

montmorillonite particles normal to the compacting 

force as they are buried more deeply. One might draw 

a line through the six non-Corcoran points on the graph 

for core hole 12/12-16 and project it downward into 

higher values of the orientation ratio, but these would 

not be confirmed by the measurements in deeper sediments from core holes 14/13-11 and 19/17-22. Most 

of these sediments were deposited rapidly on alluvial 

fans and flood plains by streams; one would not expect 

this kind of deposition to produce preferred orientation 

of clay-mineral particles. Moreover, subsequent compaction has n~t produced preferred orientation of the 

montmorillonite particles in these sediments. 

In contrast to the material deposited on alluvial fans 

and flood plains, the material that makes up the. Corcoran was deposited in the still water of a fresh-water 

lake. Each 'clay-mineral flake was allowed to settle 

individually, seeking a minimum energy position parallel to other flakes already deposited. The preferred 

orientation consequently is well developed. Similarly 

well-developed preferred orientation produced during 

the deposition of lake clays has been reported by Wu 

(1958, p. 23-29). 

MONTMORILLONITE ORIENTATION RATIO 

2 3 2 3 2 3 

l:j 0 0 0 19/17-22 ~ 12/12-16 14/13-11 

~ 

...; • (..). 

a:: 

~ • 500 :I • • \ en 

c 

z: • • :s .. == • • c • • _. 1000 • ..... 

a:l 

::z:: • ~ • • c • • ... • 1500 • 

• 

• 

• 2000 

l!.,munE 324.3.-Horizontal preferred orientation of mo-ntmorillonite in clayey sediments from core boles 12/12r-16, 14/13-11, 

and 19/17-22. Corcoran clay member of Tulare formation 

cross hatched. Procedure for measuring montmorillonite 

orientntion ratio is described by Meade (Prof. Paper 424-B, 

Art. 116). Orientation ratio of 1.0 indicates random orientation of montmorillonite particles with respect to bedding; 

ratios larger than 1.0 indicate preferred orientation in direction of bedding. 

CONCLUSIONS 

Two processes, the realinement of platy particles and 

the expulsion of water, characterize the early st~ges of 

the compaction of clayey sediments. The degree to 

which either of these processes affects the compaction of 

a given sediment depends upon the clay-mineral composition. If the principal clay mineral is illite or 

kaolinite-both of which occur as fairly large flakesthe compaction of the sediment involves both processes. 

Particles are reoriented and water is expelled concurrently. If, on the other hand, the principal clay mineral is montmorillonite--which generally occurs as 

much smaller flakes that have larger specific surfacesthe compaction of the sediment involves only one of 

these processes. Flakes of montmorillonite are not 

reoriented under pressure because the surface forces 

related to the interaction of clay particles and water 

are so much stronger than the gr:tvitational force related to the particle mass. The co·mpaction of montmorillonite-rich sediments, at least under pressures 

up to 60 kg per cm2

, comes about almost entirely 

throu(J'h the expulsion of pore water and the overcom- o . 

ing of surface attractions between montmorillorute 

particles and water. 

REFERENCES 

Bolt, G. H., 1956, Physico-chemical analysis of the compressibility of pure clays: Geotechnique, v. 6, p. 86-93. · 

Bower, C. A., and Goertzen, J. 0., 1959, Surface area of soils 

and clays by an equilibrium ethylene glycol method: Soil 

Sci., v. 87, p. 289-292. 

Buessem, W. R., and Nagy, Bartholomew, 19'54, The mechanism 

of the deformation of clay: 2d Natl. Conf. on Clays and 

Clay Minerals Proc., Natl. Acarl. Sci.-Nutl. Research Council Pub. 327, p. 480-491. 

Davis, G. H., and Poland, J. F., 1957, Ground-water conditions 

in the Mendota-Huron area, F'resno a.nd Kings Counties, 

California: U.S. Geol. Survey Water-Supply. Paper 1360-G, 

p. 409-588 . 

Diamond, Sidney. and Kinter, E. B., 1958, Surface areas of 

clay minerals as derived from measurements of glycerol 

retention: 5th Natl. Conf. on Clays and Clay Minerals 

Proc., Natl. Acad. Sci.-Natl. Research Council Pub. 566, 

p. 334-347. 

Grim, R. E., 1958, Organization of water on clay mineral surfaces and its implications for the properties of clay-water 

systems, in "rater and its conduction in soils: Highway 

Research Board Spec. Rept. 40, p. 17-~~3 . 

Inter-Agency Committee on Land Subsidence in the San Joaquin 

Valley, 1958, Progress report on land-subsidence investigations in the San Joaquin Valley, California, through 1957: 

Sacramento, Calif., 160 p. 

Kemper, W. D., 1958, Structural implkations of moisture retention by clay-size soil materials : Soil Sci. Soc. America 

Proc., v. 22, p. 5-8. 

Kinter, E. B., and Diamond, Sidney, 19f)0, Pretreatment of soils 

and clays for measurement of external surface area by 

glycerol retention: 7th Natl. Conf. on Clays and Clay Minerals Proc., New York, Pergamon Press, p. 125-134. 
D-92 GEOL9GICAL SURVEY RESEARCH 19 61 

Low, P. F., 1958, Movement and equilibrium of water in soil 

systems as affected by soil-water forces, in "rater and its 

conduction in soils: Highway Research Board Spec. Rept. 

40, p. 55-64. 

r .. utz, J. F., and Kemper, "'· D., 19•39, Intrinsic permeability of 

clay as affected by clay-water interaction: Soil Sci., v. 88, 

p. 83-90. 

Mitchell, J. K., 1956, The fabric of natural clays and its relation 

to engineering properties : Highway Research Board Proc., 

v. 35 (Natl. Acad. Sci.-Natl. Research Council Pub. 426), 

p. 693-713. 

Shepard, F. P., 1954, Nomenclature based on sand-silt-clay 

ratios: Jour. Sed. Petrology, v. 24, p.151-158. 

von Engelhardt, 'Volf, 1960, Der Porenraum der Sedimente: 

Berlin, Springer, 207 p. 

Warkentin, B. P., Bolt, G. H., and Miller, R. D., 1957, Swelling 

pressure of montmorillonite: Soil Sci. Soc. America Proc., 

v. 21, p. 495-497. 

Wu, T. H., 1958, Geotechnical properties of glacial lake clays: 

J.our. Am. Soc. Civil Engineers, Soil Mech. and Found. Div. 

Proc., v. 84, SM 3, Paper 1732, 34 p. 

325. SURFACE-WATER HYDROLOGY OF COASTAL BASINS OF NORTHERN CALIFORNIA, IN RELATION TO 

GEOLOGY AND TOPOGRAPHY 

By S. E. RANTZ, Menlo Park, Calif. 

Work done in cooper.ation with California Department of Water Resources 

The coastal drainage basins of California that are 

north of the southern boundary of Eel River basin comprise an area of 21,000 square miles. This area and 

its principal streams are shown on figure 325.1. Parts 

of the drainage basins of the northernmost streams lie 

in Oregon. Most of ·the region is mountainous with 

many peaks above 6,000 feet in altitude; the highest 

peak is ~{ount Shasta, which reaches 14,161 feet. The 

mountainous areas are generally well covered with 

timber. 

. Precipitation is distinctly seasonal, and is largely restricted to the months from October through May. 

This distribution of precipitation is controlled largely 

by the anti-cyclonic cel1 that is normally found off the 

California coast, particularly in sum1ner. Precipita:-

tion in winter occurs usually when the anticyclone either 

is absent or is far south of its usual position. 

F.rom a consideration of major landforms, the region 

can be divided into three subregions, each of which is 

hydrologically homogeneous. These major landforms 

(fig. 325.1) are the Northern Coast Ranges, the 

Klamath Mountains, and the Southern Cascades. 

The Northern Coast Ranges are ·underlain chiefly 

by a complex series of sandstone and shale, metamorphic rocks, and lavas, intruded by large masses of 

ultra-mafic rocks now largely altered to serpentine. 

Only a small part of this subregion is above 5,000 feet 

in altitude, so that there is little snowmelt runoff, and 

almost all the runoff results from the rains of late fall 

and winter. The soil and mantle rock are relatively 

impermeable and base flow is therefore poorly sustained, with the result that streamflow is very low in 

the summer and . early fall. A stream typical of the 

subregion is Eel River; graph A of figure 325.2 

shows the average monthly distribution of runoff for 

this river at the gaging station at Scotia. The great 

variability .of streamflow is immediately evident. 

During February, the month of greatest runoff, the 

average monthly flow is about 150 times as great as it is 

during September, the month of least runoff. 

The lGamath ~fountains include a rugged area lying 

between the Northern Coast Ranges on the west and 

the Southern Cascades on the east. The l{]amath 

Mountains have a co1nplex structural pattern with no 

apparent regional trend. The rocks are largely 

crystalline, consisting principally of highly metamorphosed lavas and sedimentary rocks intruded by 

granitic ·rocks. Because a large part of this subregion 

is ab0ve 5,000 feet in altitude, much of the winter 

precipitation is stored as snow, and a large amount of 

snowmelt runoff occurs in late spring in addition to the 

storm runoff in the winter. The soil and mantle rock 

are more permeable than that in the Northern Coast 

Ranges, and base flow is therefore better sustained. A 

stream typical of this subregion is Trinity River; graph 

B of figure 325.2, shows the average monthly distribution of runoff for this.river at the gaging station at 

Lewiston. Streamflow variability is less .pronounced 

than in the N orthe1-n' Coast Ranges subregion; the 

average monthly flow for May, the month of greatest 

runoff, is about 30 times as great as it is for September, 

the month of least runoff. 
SHOR'l' PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-93 

40" 

EXPLANATION 

t?ZI Northern Coast Ranges 

Klamath 

-

Mountains 

D Southern Cascades 

20 0 20 40 60 MILES 

Frou1u~ 325.1.-Map showing major landforms and principal 

streams of northwestern California. 

The Southern Cascades, east of the I{]amath Mountains n,nd north of the Sierra Nevada, are underlain by 

lava and pyt·oclastic rocks. The upper I{]amath River, 

front ICeno, Oreg., to the mouth of 'Villow Creek in 

California, flows in a canyon cut into these rocks. The 

.Klamat-h H iver basin above l(eno and the closed basins 

south and east of IQamath River lie in a plateau region 

like"·ise underlain largely by lava and pyroclastic 

rocks. T'h is plateau has poorly developed surface 

clrainage because the highly permeable nnd fractured 

lava allows ready infiltration of precipitation and 

snowmelt.. .Seeps are common and large springs are 

numerous. Consequently, base flow is better sustained 

in this subregion than in either of the other two. In 

some of the headwater streams in Oregon., extensive 

marsh areas exert a regulating effect on the streamflow. 

Because of the high altitude of the subregion, the 

volume of snowmelt runoff is significantly large. No 

one stream typifies all of those of the Southern Cascade 

subregion, but graph 0 of figure 325.2 shows the 

average monthly distribution of runoff of Fall Creek, 

a spring-fed tributary of the l{]amath River. The 

equable character of the flow is apparent; no month 

has less than 7 percent of the annual runoff, nor more 

than 11 percent. 

..... 

..... 

0 

z 

::I 

a:: 

...J 15 < 1-

0 

1-

..... 

0 

~ 10 IJJ 

() 

a:: 

IJJ 

a.. 

..... 

..... 

0 

z 

::I 

a:: 

...J 15 < 1-

0 

1-

..... 

0 

~ 10 IJJ 

() 

a:: 

IJJ 

a.. 

EEL RIVER AT SCOTIA, CALIF. TRINITY RIVER AT LEWISTON, CALIF. 

~1oP=~~~~~~~~=q 

z 

::I 

a:: 

...J 

< 1-

0 c. 1- 5~----------------~ ..... 

0 

1-

z 

IJJ 

() 

a:: 

~ o ... >uc:.o..:==>-cu>-.o.: 

~~~~~~~~~~ciJ~ 

FALL CREEK AT COPCO, CAUF. 

FIGURE 325.2.-Mean monthly distribution of runoff at selected 

stream-gaging stations. 
D-94 GEOLOGICAL SURVEY RESEARCH 19 61 

326. CENTRAL VENT ASH-FLOW ERUPTION, WESTERN SAN JUAN MOUNTAINS, COLORADO 

By RoBERT G. LuEDKE and WILBUR S. BURBANK, Washington, D.C., and Exeter, N.H. 

Work done in cooperation with the Colorado State Metal ~lining Fund Board 

A volcano-tectonic depression is located near the 

western edge of the Tertiary volcanic field in the San 

,J nan Mountains of southwestern Colorado (fig. 326.1). 

The younger Silverton and Lake City calderas are within and superimposed upon this depression. Geologie 

mapping of the northern part of the Silverton caldera 

and the contiguous part of the depression has disclosed 

a welded ash-flow deposit of limited areal extent and 

the loca.tion of its vent. · 

The ash flow erupted from a nearly circular vent 

about a mile in diameter located west-northwest of Engineer Mountain (fig. 326.2). The vent lies between 

~--- -------, I I 

I 

N 

COLORADO 

I 

' _______ _j 

EXPLANATION 

Fault-.-

Dashed where inferred, 

hachures !>n downthrown side 

0 10 20 MILES 

FIGURE 326.1-Generalized geologic map of the western San Juan 

region, Colorado, showing location of the depression and the 

Silverton and Lake City calderas within it. Tertiary volcanic 

rocks and minor intrusives, stippled; pre-Tertiary rocks, no 

pattern. Rectangle shows area of figure 326.2. 

the peripheral ring-fault zone of the Silverton caldera 

and the probable ring-fault zone of the volcano-tectonic 

depression. The crater filling of ash-flow material is 

partly covered, but where exposed, it has vertical to 

steeply inclined and inwardly dipping flow planes. 

The ash flow was erupted upon an uneven erosion surface and was confined to a northeasterly trending 

trough about 10 miles long and as much as 2,% miles 

wide. In the narrower and deeper part of the trough 

southwest of the vent, the ash flow was deposited on 

lava flows and related pyroclastic rocks of the San 

Juan tuff and the Silverton volcanic series, both of 

middle Tertiary age, and abutted against a volcanic 

dome in the depression ring-fault zone in what is now 

a part of Hayden Mountain. Northeast of the vent 

the ash flow spread as a sheet upon bedded tuff of the 

Silverton series in the shallower and broader part of 

the trough, and wedged out upon a topographic high 

northeast of Dolly Varden Mountain. The ash flow 

has a preserved thickness of about 1,000 feet at Mount 

Abrams southwest of the vent and only about 200 feet 

at Dolly Varden Mountain northeast of the vent. The 

volume of material erupted is estimated to have been 

between llf2 and 2 cubic· miles . 

. Welded ash flows of the Potosi volcanic series of 

middle and late Tertiary age unconformably overlie the 

ash flow to the southwest and in part the vent area. 

Northeast of the vent the ash flow is overlain conformably by a variable thickness of bedded tuff similar 

to that underlying the ash flow. This position of the 

welded ash flow between nearly identical deposits of 

bedded tuff led Cross, Howe, and Irving in 1907 to 

interpret the welded ash flow as a sill intruding the 

Henson tuff of the Silverton volcanic series, and to 

name it the American Flat latite. 

The welded ash flow is light to dark gray and 

weathers greenish gray to grayish brown. Locally it 

is altered to a rust color or bleached almost white and 

speckled with limonite. The outcr:ops have a conspicuous slabbiness parallel to the foliation, but nowhere is 

vertical columnar jointing well developed. 

The rock contains abundant crystal fragments and 

sparse pumiceous fragments in a vit.roclastic matrix; 

very few accidental rock fragments are included. The 
SHORT PAPERS IN THE GEOLOGrC AND HYDROLOGIC SCIENiCES, ARTICLES 293-43 5 D-95 

r 

Ouray 

0 

EXPLANATION 

Ash-flow deposit 

Probable original extent 

of ash-flow deposit 

.... . . . . . . ..... 

Vent 

--,--,--.,.-· -rFault 

Dashed where inferred, 

hachures on downthrown side 

2 3 MILES 

FIGURE 326.2.-Generalized geologic map of the north side of the Silverton caldera showing outcrops and probable extent 

of ash-flow deposit. 

matrix is dense and characterized by eutaxitic structure 

but locally a.ppears structureless. The fragmental 

intratelluric crystals, listed in decreasing ·order of 

abundance, are qunrtz, biotite, potassic feldspar, plagioclase (oligoclase-andesine), amphibole, and accessory 

minerals. Chlorite, carbonate minerals, sericite, iron 

oxides, and locally pyrite, or limonite after pyrite, are 

common alteration products throughout much of the 

rock. The vitroclastic structure of the matrix is partly 

to completely obliterated by crystallization to a finegrained aggregate of potassic feldspar, quartz, and accessory minerals. A.xiolitic and spherulitic intergrowths of feldspar and quart.z are conspicuous in the 

flnttened pun1iceous fragments. The composition of 

the rock is probably a quartz latite or a rhyolitic quartz 

latite. 

The welded ash flow seems to represent the deposit of 

a single eruption and is a simple cooling unit (terminology of Smith, 1960). Variations in the degree and 

amount of welding and compaction of the tuffaceous 

and· pumiceous material are noticeable owing to lateral 

thinning-and to topographic irregularities on the underlying surface. 

The recognition of this ash flow and its vent affords 

a better understanding of the petrologic and volcanic 

processes occurring during the evolution of the Silverton volcanic series and the volcano-tectonic depression. 

Preceding and succeeding volcanic activity was principally a quiet effusion of lava alternating with explosive 

ejection of ash; the materials erupted were andesitic 

to rhyodacitic in composition. In contrast, the ashflow eruption was a catastrophic hot avalanche of more 

silicic material. These contrasting features indicate 

(a) different stages of magmatic differentiation either 

by fractionation or contamination, and (b) different 

modes of eruption. This small local ash-flow eruption 

apparently represents an aberrant phase in the waning 

stages of the Silverton eruptions. 

Recognition of this central vent ··establishes that at 

least one local ash-flow eruption in the San Juan region 

was from a conduiL In the absence of local deep erosion the position of the vent would not have been recognized from features exposed in the overlying eruptive 

debris. Thus it is possible that other local vents of 

this type and related ash-flow eruptions may be more 

common in the San Juan volcanic region than are 

readily disclosed. 
D-96 GEOLOGICAL SURVEY RESEARCH 19 61 

Material similar to and included as part of the American Flat latite is reported by Cross, Howe, and Irving 

(1907) near Uncompahgre Peak, about 6 miles northeast of Dolly Varden Mountain. This occurrence has 

not been examined by us, but if it is an ash-flow deposit,· 

it may represent another local eruption from a separate 

vent. 

REFERENCES 

Cross, Whitman, Howe, Ernest, and Irving, J.D., 1907, Description of the Ouray quadrangle [Colorado] : U.S. Geol. Survey Geol. Atlas Folio 153. 

Smith, R. L., 1960, Zones and zonal variations in welded ash 

flows: U.S. Geol. Survey Prof. Paper 354-F, p. 149-159. 

327. EIGHT MEMBERS OF THE OAK SPRING FORMATION, NEVADA TEST SITE AND VICINITY, NYE AND 

. LINCOLN COUNTIES, NEVADA 

By E. N. HINRICHS and P. P. 0RKILD, Denver, Colo. 

Work done in cooperation with the U.S. Atomic Energy Oomrni8sion 

Te.rtiary volcanic rocks that crop out extensively in 

the Nevada Test Site were named the Oak Spring formation by Johnson and Hibbard (1957, p.367). The 

formation is of Miocene ( ? ) or younger age, is at least 

2,200 feet thick, and is composed of welded and nonwelded silicic tuff, tuffaceous sandstone and siltstone, 

rhyolite, rhyodacite, and basalt. 

As the result of recent geologic mapping in five 

71;2-minute quadrangles and reconnaissance in about 15 

other quadrangles in and around the Nevada Test Site, 

the Oak. Spring formation is now well enough known 

to be divided into .an informal lower member and 

seven formal members here named: Tub Spring, 

Grouse Canyon, Survey Butte, Stockade vVash, 

Topopah Spring, Tiva Canyon, and Rainier Mesa 

members. 'Vith the exception of the basal m~mber, 

they are named after geographic features shown on 

figure 327.1 (p. D-100). Details of the lithology, the 

distribution, and thickness of the newly named members are given on table 327.1, and the correlation of the 

units in selected stratigraphic sections is given on figures 327.~ (p. D-101 to -103). 

Hansen and Lemke (1957) informally divided the 

formation into eight units as a result of detailed map- -

ping of about 2- square miles on the east side of Rainier 

Mesa in Tippipah Springs N'V quadrangle (fig. 327.1). 

Extension of geologic mapping to the limits of the 

quadrangle resulted in an additional 19 map units 

(Gibbons and others, 1960). Correlations of these 

units with the· eight members of this paper are given 

on table 327.1. 

REFERENCES 

Gibbons, A. B., Hinrichs, E. N., Hansen, ,V. R., and Lemke, 

R. ,V., 1960, Preliminary geologic map of the Tippipah 

Spdng N"7 quadrangle: U.S. Geol. Survey TEI-754, openfile report. 

Hansen, W. R., and Lemke, R. ,V., 1957, Geology of the USGS 

and Rainier tunnel areas, NeYada Test Site: U.S. Geol. 

Survey TEI-716, open-file report. 

Johnson, l\f. S., and Hibbard, D. E., 1957, Geology of the Atomic 

Energy Commission Nevada Proving Grounds area, NeYada: U.S. Geol. Survey Bull. 1021-K, p. 333-384. 
SHORT PAPERS IN THE' GEOLOGrC AND' HYDROLOGIC SCIENCES, ARTICLES 293-435 D-97 

TABLE 327.1-Descriptions, thicknesses, disting.uishing features, and equivalent units on earlier maps of eight members of thE: Oak Spring 

formation, Nevada Test Site 

Distribution and thickness 

Thickest measured section 

is about n mile north of 

Survey Butte. Exposed 

on Pahute Mesa ltnd 

southwnrd to Lookout 

Peak and efLStward to 

Nye Cnnyon. Unit is 

more than 655 feet 

thick. 

Shoshone Mountn.in northward to Tippipah Spring 

nnd en.stwttrd to N ye 

and Lincoln County 

line. Unit is 0 to 550 

feet thick. 

Thickest on south flank of 

French Peak. Extends 

from Shoshone Mesa 

southward to Lookout 

Peak and eastward to 

county line. Absent in 

western part of test site. 

Unit is 0 to 250 feet 

thick .. 

Thickest at 311 Wash. 

Extends from 311 Wash 

north\vard to pinchout 

on Rainier Mesa, southwn.rd to Shoshone 

Mountnin, eu.stwnrd to 

the county line, nnd 

westwu.rd to Calico Hills 

and probably to Y uccn 

Mountain. Unit is 0 to 

900 feet thick. 

Description 

Megascopic Microscopic 

Rainier Mesa member, equivalent to map unit TosS of Hansen and Lemke (1957) 

Gray and reddish-brown welded tuff marked 

by distinct eutaxitic structure; subordinate 

amounts of black vitrophyre; white, pink, 

and tan nonwelded tuff at base; overlain by 

densely welded tuff locally separated by zones 

of partially welded or nonwelded tuff. In 

southeastern part of test site entire member is partly welded and glassy. Lower 

contact gradational at Rainier Mesa, and 

uncomformable southward. 

Phenocrysts of sanidine, 

anorthoclase, quartz, 

plagioclase, biotite, 

and other mafic minerals make up 10 to 30 

percent of rock. 

Tiva Canyon member, upper part; (new map unit) 

Gray, purple, and brown densely welded tuff, 

much of which weathers platy; local zones 

of lithophysae and spherulites in middle and 

upper parts; at the top a zone of porous 

finely crystalline partially welded tuff that 

is thickest in vicinity. of French Peak; basal 

part is white and pink nonwelded shards and 

pumice, and is locally cavernous. Member 

becomes progressively less w·elded and more 

glassy from French Peak eastward. Black 

vitrophyre near base locally in central part 

of test site. 

Phenocrysts compose less 

than 5 percent of basal 

tuff; 10 to 25 percent 

of tuff in middle and 

upper parts. Phenocrysts chiefly of quartz 

and potassium feldspar. 

Mafic minerals less 

than 1 percent. 

Tiva Canyon member, lower part; (new map unit) 

Gray and yellow fine to lapilli bedded tuff, 

zeolitic near French Peak; medium to very 

thick bedded; local thin beds contain more 

than 20 percent rock fragments up to 3 em 

long; weathers to moderate ledgy slopes. 

Lower contact locally unconformable. 

Phenocrysts of quartz 

and feldspar, 10 to 20 

percent; biotite, less 

than 5 percent, fragments of gray welded 

tuff, less than 5 percent. 

Topopah Spring member; equivalent to map unit T72 of Gibbons and others (1960} 

Brown and reddish-purple densely welded 

tuff; persistent black and brown vitrophyre 

in upper part and local vitrophyre in lower 

pnrt; local zones of geodes and lithophysae; 

strongly eutaxitic in western part of the 

test site; basal tuff non welded to partly 

welded and locally silicified; pale-red 

crystal-poor welded tuff in the lower part of 

member; pumice fragments are as much as 

18 inches long at eastern edge. Member 

forms steep slopes and cliffs. 

Phei1ocrysts of feldspar, 

quartz, and biotite 

make up about 1 percent of the tuff at 

base, increasing upward to 15 percent 

near top. Plagioclase 

predominates in lower 

vitrophyre; potassium 

feldspar in upper vitrophyre. Fragments of 

dense dark rock make 

up less than 5 percent 

of the rock. 

Distinguishing features 

Cliffs of dark welded tuff, 

steep slopes, and conical 

forms of nonwelded and 

partly welded tuff; 

conspicuous biotite. 

Steep slopes of purple 

platy-weathering densely welded tuff. Caverns 

in pink basal tuff. 

Ledgy moderate slopes of 

yellow bedded tuff. 

Black vitrophyre at top; 

local geodes and lithophysae; crystal-poor 

welded tuff in lower 

part. 
D-98 GEOLOGICAL SURVEY RESEARCH 1 9 6 1 

TABLE 327.1-Descriptions, thicknesses, distinguishing features, and equivalent units on earlier maps of eight members of the Oak Spring 

formation, Nevada Test Site-Continued 

Distribution and thickness 

Extends from western and 

southern parts of 

Rainier Mesa southward to Tippipah 

Spring, and westward 

to Fortymile Canyon. 

Unit is 0 to 290 feet 

thick. 

Thickest on the east side 

of Rainier Mesa; extends from there southward to Tippipah 

Point, northward about 

15 iniles, westward to 

Pahute Mesa, and eastward to Quartzite 

Mountain. Unit is 60 

to 750 feet thick. 

Present from type locality 

at Grouse Canyon · 

northward to Indian 

Spring, southward to 

Big Butte, eastward to 

Oak Spring Butte, and 

westward to Fortymile 

Canyon. Unit is 0 to 

175+ feet thick. 

About coextensive with 

upper part. Unit is 0 

to 400 feet thick. 

Description 

.Megascopic Microscopic 

Stockade Wash member; equivalent to map unit T7t of Gibbons and others (1960) 

Lenticular deposit of white, pale-gray, and 

pale-brown nonwelded to partially welded 

tuff; most of the member contains nonstratified orange and tan pumice fragments 

as much as half an inch long; local calcite 

cement; base is zeolitic in places. West of 

Tippipah Spring are contorted layers and 

closely spaced polygonal joints possibly of 

fumarolic origin. Forms cliffs, rounded 

knobs, and low hills. 

Phenocrysts of quartz, 

feldspar, and biotite 

amounting to less than 

5 percent of the tuff. 

Survey Butte member; equivalent to map unit Tos7 of Hansen and Lemke (1957) 

Predominantly pale-gray and brown wellbedded tuff composed chiefly of glass 

shards and fine and coarse unaltered 

pumice; generally poorly cemented and 

friable; beds are tabular and lenticular, 

some crossbeds and channel fillings. The 

member thins southward from Rainier 

Mesa and interfingers with the Stockade 

\V ash, Topopah Spring, and Tiva Canyon 

members. Forms steep slopes generally 

covered by colluvium. Lower 150 feet on 

east side of Rainier Mesa is zeolitic. 

Fragments of dark dense. 

volcanic rocks and 

glass make up 20 percent or less of the tuff 

. phenocrysts of feldspar and quartz make 

up 5 percent or less. 

Grouse Canyon member, upper part; equivalent to map unit TosG of Hansen and Lemi:'e (1957) 

Reddish-brown, greenish-gray, and yellowishgray densely welded tuff; distinctly eutaxitic; black- and white-zoned lenses of 

flattened pumice up to 2 inches long. On 

the east side of Rainier Mesa the welded 

tuff is present only in synclines. Local 

conglomerate and scattered pebbles and 

cobbles of rhyolite and granite both are in 

welded tuff, and· in black vitrophyre on 

west side of Rainier Mesa. Lower contact 

gradational. 

Welded tuff contains 3 

to 9 percent phenocrysts of sanidine, 

anorthoclase, and 

quartz. Black 

vitrophyre contains 

lenses of gray pumice 

and about 30 percent 

phenocrysts, chiefly of 

feldspars. 

Grouse Canyon member, lower part; equivalent to map unit Tos5 of Hansen and Lemke (1957) 

Medium-gray vitric tuff and greenish-yellow 

zeolotic tuff in beds 2 inches to 3 feet thick; 

thin beds composed of fine well-sorted 

thinly laminated pumice; local sparse 

pebbles and lenses of blaok obsidian and 

fragments of granitic rock as much as an 

inch long. Lower contact is an erosional 

unconformity. 

Phenocrysts compose less 

than 5 percent of rock. 

Distinguishing features 

Rounded knobs of pale 

nonbedded tuff having 

contorted layers. 

Distinct parallel laminated and crossstratified gray beds 

alternating with nonlaminated; pale-brown 

beds. 

Makes cliffs; contains 

zoned lenses of flattened pumice having 

eutaxitic structure, 

and cobbles of rhyolite 

and granite. 

Extensive greenish-gray 

and yellow beds, 

distinctively laminated. 
SHORT PAPERS IN THE GEOLOGrC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-99 

TABLE 327 .!-Descriptions, thicknesses, distinguishing features, and equivalent units on earlier maps of eight members of the Oak Spring 

formation, Nevada Test Site-Continued 

.Distribution and thickness 

Found on north and east 

sides of Yucca Flttt. 

Unit is 0 to 250 feet 

thick. 

Widespread basctl unit 

exposed on the west, 

north, and east sides of 

Yuccn. Flat, and at a 

few plnces south of the 

Fln.t. Unit is 0 to . 

1,100 feet thick. 

Description 

Megascopic Microscopic 

Tub Spring member; probably equivalent to map unit Tgor of Gibbons and others (1960) 

Greenish-gray welded tuff, gray vitrophyre, 

and reddish-brown partially welded pumice; 

inclusions of rhyolite, welded tuff, and 

Paleozoic rocks; base is non welded gray 

vitric and at some places yellow zeolitic 

tuff; the member occupies a stratigraphic 

position between units Tos4 and Tos5 of 

Hansen and Lemke (1957). Forms cliffs 

and benches. 

Phenocrysts of sanidine, 

anorthoclase, quartz, 

and mafic minerals 

compose as 30 percent 

of the rock. 

Distinguishing features 

Fragments of pumice 

and rhyolite as much 

as 1.2 inches long near 

pinehout on Paleozoic 

rocks about 3 miles 

west of type locality; 

abundant phenocrysts. 

Lower member; equivalent to map units Tw 1 to 4, Tej, Tg, and Tgo of Gibbons and otbt>rs (1960) 

Mostly thick lenticular nonstratified deposits 

of gray, yellow, orange, and red zeololitic 

tuff in basins in Paleozoic rocks; also includes tuffaceous sandstone and siltstone 

that locn1ly contain plant fossils, and minor 

amounts of welded tuft and olivine basalt; 

local basal breccia of Paleozoic rocks. 

The nonstratified tuffs intertongue with 

the Tunnel beds, which consist of gray, 

yellow, orange, a.nd red paralled-bedded 

zeolitic tuff 675 to 900 feet thick at the 

type locality on the east side of Rainier 

Mesa. The Tunnel beds are equivalent to 

map units Tos 1 through 4 of Hansen and 

Lemke (1957). Member forms rounded 

ledges and low cliffs alternating with modern.te to steep slopes. The lower member 

is conformably overlain by the Tub 

Spring member on the north and east sides 

of Yucca Flat; it is unconformably overlain 

by the Gt·ouse Canyon member on the west 

side. 

Phenocrysts make up 5 

to 20 percent (chiefly 

5 to 15 percent) of 

nonwelded tuff, and 

rock fragments make 

up 20 percent or less. 

\V elded tuffs contain 

up to 5 percent biotite 

and hornblende. 

Brightly colored cliffforming tuff; locally 

thick units indicate 

deposition in local 

basins; pla.nt fossils of 

Miocene and Pliocene 

ages. 
D-100 

NEVADA 

37° 15' 

37°00' 

GEOLOGICAL SURVEY RE-SEARCH 19 61 

EXPLANATION 

~ Type section 

x3 

Measured section 

0 5 

~dian SpriWJ""o """'---

... 41 ·. ~(7 

< \ / ~ '-···\. 

Q: "- ·. 

~~::~ ... ~ .. 

\__ _ _...,-···~ ... Q ... ...,.--·· .. .....__ / ----.... ... '-....... 41 __ .. .____.·,----- .. 

" 

10 15 MILES 

FIGURE 327.1.-Map showing location of measured sections of eight members of the Oak Spring fonnation shown on 

figures 327.2-327.4. 
WEST 

A 

6 

Stockade Wash 

EXPLANATION 

Nonbedded tuff ·e~ FEET 

(s, silicified) z 0 9 

Bedded tuff ~ ~ (z, zeolitic) ~ 8 Basalt 100 ... 

... 

ar:: 

(ll 

Vitrophyre ... 

0 200 

D, densely welded 

P, partiaiiy weided 

N, nonwelded 

b, brown 

bk, black 

g, gray 

gn, green 

o, orange 

p, purple 

pi, pink 

r, red 

y, yellow 

w, white 

4 

East Rainier Mesa 

.3 

North of Survey Butte 

p 

b 

p pi 

Rainier Mesa member p pi 

p 

PI g 

p 

D r 

r 

D b 

Survey Butte member b 

D g 

g 

r 

Lower part of Grouse Canyon member 

5 

Captain Jack Spring 

g 

~ t~l beds ~ z r 

:>l_:_l I y I Lower member 

~=---~ lr I ..:::.- ~-...!...J I I 

~=--~ I I ""- ~=f I I 

~ I I ~ - - I £ 1', I s 

2 

:k Spring/ 

1 D L!r 

I z IN I g 

I I IB 

I IN 

I I IB 

EAST 

A' 

II I 

FIGURE 327.2.-Sections of the Oak Spring formation on an east-west line, north-central Nevada Test Site. For locations see figure 327.1. 

g 

U1 

~ 0 

~ 

8 

"'d 

> "'d 

trl 

~ 

U1 

z 

~ t':! 

a 

trl 

0 

t"4 

0 

0 

8 

tj 

~ 

tj 

~ 

~ 

0 

t"4 

0 

a 

1-1 

(") 

~ 1-1 

trl 

~ q 

trl 

~Ul 

> 

~ .8 

~ trl 

Ul 

t-.:1 

co 

c.,) 

I 

~ 

~ 

Ct 

tj 

I 

~ 

0 

~ 
D-102 GEOLOGICAL SURVEY RESEARCH 1 9 6 1 

NORTH 

B 11 

Tippipah Point 

~(V~ 

SOUTH 

B' 

8 

Grouse Canyon 

r-N\./"1"""~ 

0 b 

0 b 

p pi 

N w 

9 

Big Butte ---- _ ---:;-,.;::;(0-v;:;- --- Topopah Spring 

-c:::::::::: ~ ..... -- P s member 

--~-= -~~ 10 

member -- B ---= .JI •AA...,. =-=: w 'V 

-=..=- o r 

Will 

b Survey Butte = = 1\ippipah Spring 

r===--~4-4 ==~ : 0: 1----11---l~ 0 :~-~ ~=-~ - St k d . - -=-=- p ~~=.:;: _ ~ ~ -= ocae=-~ _ ~~---"' '0 ~ - _ Wash _ ~ 

- 8 ~ ...... % ... ." Kmember _ _=: - ~ ., p b -- w z 

~ ~ --= - .;_ 0 =-::!. r % ....""« _·: pi 

--=- ., - : I-- - B -=-- B· -~d --::. b --

- ':'.-: -o -- 1-- -- 0-t, ~~~-- --

. - pi ~ ~-

~-+-~-~ ~ -~ y - __ -

=-~ Y Tunnel beds -oo>.,. _.:...::::: "~.=.-= 

-==-=- r ~-.:... -~ _""""1'==..;='---1-..!!.B-k_ f= =1- 1--

----- y .......... =-=; 

B .;:;:::-......._ ~ --= ~ f.--

y 

B 

....-

=-~ pi 

I-=~ _ pi lower member ~ :::::: 1---+-+-1 1===- . - ~-

N 

L- pi 

- 0 r 

'V ""v 

0 r 

_,... ...... ~ 

.. v , .. 

N 0 

pi 

w 

N ~i 

y 

w 

pi 

o•c N B 

0 

N b 

12 

Shoshone Mesa 

p pi 

0 r 

p B 

0 

Tiva 

Canyon 

pi member N b 

N pi 

_p _ _ II 

bk 

0 p 

0 B 

0 bk 

p b 

w 

y 

0 B. 

r 

s 0 b 

s N 

p w 

s N ~ 

13 

Jackass Divide 

(V'\A.(V,.V 

B 

0 _b 

0 

p B 

:~~ 5 N B 0 B ~ 

r =-==~ ·-rgN 

s 0 b 

w 

s N ,r:; 

gn 

,;,. oA 

0 

•AMI ,AA 

•v 'll'" 

EXPLANATION 

Nonbedded tuff 

(s, silicified) 

Bedded tuff 

(z, zeolitic) 

Vitrophyre 

[ 

[,., 

D, densely welded 

P, partially welded 

N, nonwelded 

b, brown 

bk, black 

g, gray 

gn, green 

o, orange 

p, purple 

pi, pink 

r, red 

y, yellow 

w, white 

FIGURE 327:3.-Six seetions of the Oak Spring formation on a north-south lin~, north-eentral Nevada Test Site. For 

locations see figure 327.1. 
~ 

WEST 

c 

13 

Jackass Divide 

~~ 

D 

g 

b 

14 

Four Corners Butte 

,/\) ,I\ 

15 

311 Wash 

an·d Vitrophyre Wash 

~ 

Dl: 

N b 

16 

Yucca Pass 

""""T~ 

Dtp 

Plb 

17 

Massachusetts Mountain 

~::NJJvttfi~ -~ 

IAAA 

b 18 pi 

N 

D North side 

West side I P 1 s MassanmVchusetts Mountain 

0 

g 

Dl~ 

Ptg 

A.AIA..A. <'VV 

1 s I 

~ s 

lt 

EXPLANATION 

Nonbedded tuff ~FEET <s. silicified> 1 s 1 ~ 1 ; r o 

Bedded (z, zeolitic) tuff -~ ~ l:; ~ c5 ~· t - t:l (.) 100 

a: 

Cl 

Vitrophyre ~ 200 

0, densely weld~d 

P, partially welded 

N, nonwelded 

b, brown 

bk, black 

g, gray 

gn, green 

o, orange 

p, purple 

pi, pink 

r, red 

y, yellow 

w, white 

D.g 

PI: 

N w 

~ b 

k 

D l·p 

b 

b D 

p 

Dlb 

....,..r'V 

Tiva Canyon member 

Topopah Spring member 

/ 

./ 

/ 

/ 

/ 

/ 

/ 

// 

Dip 

Dig 

Plo 

/ 

// 

// 

PI& 

Dlb 

Dip 

p pi 

N w 

Dlb 

Dlb 

sIp I~ 

lower member 

19 

French Peak 

p I g 

b 

DIP 

DIP 

p pi 

N w 

D 

gn 

gn 

y 

EAST 

C' 

20 

Scarp Canyon 

lili 0 

0 

Dlo 

g 

Dtp 

D1g 

P Lo 

~ g 

:=-z:::: 

k 

r 

Z IN I• 

f---+-+yb 

z IN 

s 

,, 

y 

g 

y 

g 

r 

FIGURE 327.4.-Eight sections of the Oak Spring formation on an east-west line, central Nevada Test Site. For locations see figure 327.1. 

(f) 

~ 0 

::tl 

~ 

'"tl 

> 

'"tl 

t_:rj 

::tl 

[/) 

z 

~ t_:rj 

0 

t_:rj 

0 

t'4 

0 

0 

~ 

(") 

~ '=' 

~ 

-< '=' ::tl 

0 

~ 

0 

0 

..... 

(") 

~ ..... 

t_:rj 

~ t_:l:j 

!f1 

> ::tl 

j 

(") 

~ 

t_:rj 

C/1 

t..:) 

~ 

I' 

.;.. 

~ 

~ 

t::1 

I 

~ 

0 

c,., 
D-104 GEOLOGfCAL SURVEY RESEARCH 1 9 6 1 

328. ELEANA FORMATION OF NEVADA,.TEST SITE AND VICINITY, NYE COUNTY, NEVADA 

By F. G. PooLE, F. N. HousER, and P. P. 0RKILD, Denver, Colo. 

Work done in cooperation with the U.S. Atomic Energy Commission 

Recent stratigraphic study of nearly 8,000 feet of 

clastic rocks of Carboniferous age in the Nevada Test 

Site region (fig. 328.1) has yielded new information on 

late Paleozoic sedimentation and structural history in 

south-central Nevada. These clastic rocks were originally mapped by Ball (1907) as the·Weber conglomerate of Pennsylvanian age. In the northern part of the 

test site, an incomplete part of this Carboniferous sequence was named Eleana formation by J olmson and 

Hibbard ( 1957), and on the basis of stratigraphic position and lithologic similarities to strata in central 

Nevada, they considered the ·formation as probable 

Late Mississippian in age. Southeast of the test site, 

the Narrow Canyon limeston.e of Late Devonian and 

Early Mississippian age and the l\{ercury limestone of 

Early l\{ississippian age, as defined by Johnson and 

Hibbard (1957), are here correlated with the lower part 

of the Eleana formation. 

LITHOLOGY 

The Eleana formation, which is at least 7,700 feet 

thick, is known only by means of a composite of partial 

sections. Correlation of these sections is difficult due 

to structural complexities and partial cover by younger 

deposits and is considered tentative. 

The four major rock types that make up the Eleana 

formation are (a) argillite, (b) siliceous siltstone and 

very fine grained quartzite, (c) quartzite and conglomerite, 1 and (d) limestone. The formation is divided 

into ten major lithologic units, in ascending order from 

A through J (fig. 328.2). lJnit A is limestone and 

limestone conglomerate; unit B is argillite; unit C is 

quartzite and conglomerite; unit D is argillite and 

quartzite; unit E is argillite; unit F is quartzite, argillite, and conglomerite present at Grouse Canyon; unit 

G is quartzite, conglomerite, and argillite; unit H is 

argillite; unit I is limestone and argillite; and unit J 

is argillite. 

The argillite is yellowish brown to pale red, laminated, and commonly contains cubic iron oxide pseudomorphs after pyrite, plant stem imprints, and lightcolored sinuate markings on stratification planes that 

1 The term "conglomerite" ts used here for conglomerate wtth a sand· 

stone mntrlx that has the Induration of quartzite. 

are interp~eted as worm trails and borings ( J. T. Dutro, 

Jr., written communication, 1960). 

The siliceous siltstone and very fine grained quartzite 

are brown to tan and commonly contain plant stems, 

convolute laminae, flow casts, current lineation, current 

ripple laminae, and small-scale cross-laminae. 

The quartzite and conglomerite are brown and locally 

contain small- to medium-scale cross-laminae, current 

ripple laminae, and contorted strata. Much of the conglomerite has graded bedding, and locally gravels are 

imbricated. Pebbles, cobbles, and rare boulders in the 

conglomerite are composed, in order of abundance, of 

subangular to rounded chert, quartzite, argillite, quartz, 

and ~imestone. 

Gray and brown fossiliferous coarsely crystalline 

limestone in unit I and upper part of unit H locally 

contains stringers of chert, and pebbles and cobbles of 

chert and subordinate argillite and limestone. Limestone in the upper part of unit J. is ferruginous, fossiliferous, and occurs as lenses in the top 1 to 2 feet of 

thic~ quartzite beds. 

The lower unit of the Eleana formation is known 

only at Carbonate Wash (fig. 328.2) where it is separated by an erosional unconformity from dolomite of 

Devonian age below. This basal unit is composed of 

interstratified laminae to very thjn beds of gray finely 

crystalline limestone and limestone conglomerate, an:O. 

subordinate oeds of limy sandstone and rare quartzite. 

Most of the conglomerate contains fossiliferous limestone pebbles, cobbles, and rare boulders as large as 4 

feet in maximum diameter in a limestone matrix. The 

beds of this unit grade upward into argillite of unit B. 

(fig. 328.2) . 

The upper contact of the Eleana formation is best 

exposed at Red Canyon. Here gray aphanitic to finely 

crystalline Tippipah limestone rests with sharp contact 

on a brown very fine to fine-grained bed of conglomeratic quartzite assigned to the Eleana formation. The 

abrupt lithologic change suggests an unconformity. 

The depositional environment of the Eleana formation, interpreted from lithology, sedimentary structures, fossils, and regional sedimentary facies, is b~­

lieved to have been largely marine. 
SHORT PAPERS IN THE GEOLOGJIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-105 

8 miles 

0~ 

~ z 

~ 

z ..... 

EXPLANATION ~0~ 

§ (~;; (/) a:: z LoJ 

~ n. n. Tippipah limestone z z (/) 

:::> 

r~ 0 

ITIJ]J a:: 

~0~ LoJ 

~z_. ~ 

~>- z N Eleana formation - (/) 0 ~.z CXl 

r~ a:: 

<( 

- ~ ~ u 

~ <( 

z -

~ n. Mercury and Narrow -on. 

zzu; Canyon limestones §?<!!? >:>->>>>>> w (/) 0 (/) 

Line of measured sections ~ 

ChevrO'nB point upward stratigraph.icaUy 

Quartzite 

Mountain 

YUCCA 

FLAT 

116° +37° 

nucca \J Playa 

FRENCHMAN 

I 

I .I 

>< E-< 

I 

I 

I 

I 

24 miles Frenchmda·[? Playa I 

.) 

I 

g I LINC~~~TY 

~I CLARK COUNTY 

I 

I 

FLAT I 

I I I I 

: I j~Narrow I Canyon 

I 

I 

L-----:---·-· ---.---.---.-------.---·-----· r·- ___ JI 

I • . Lathrop Wells 

• 

0 5· 10 MILES ~~e~'?'J 

l!"'~oUin: 3::l8.l.-Mat) of Nevada '!'est Site and vicinity showing location of measured sections and outcrops of Tippipah 

limestone, Eleana formation, Mercury and Narrow Canyon limestones. 

604403 0-61--8 
z 

~ 

z 

~ UJ 

0 

B 

1300 ft 

GEOLOGICAL SURVEY RESEARCH 1 9 61 

Grouse 

Canyon 

Red 

Canyon 

F 480+ ft 

EXPLANATION 

laminated argillite 

laminated to thick-bedded 

quartzite 

Thin- to thick-bedded conglomerite and conglomeratic 

quartzite 

laminated to thick-bedded limestone, chert layers and nodules 

laminated to thick-bedded limestone with intercalated argillite laminae 

laminated to thick-bedded limestone and limestone conglomerat~. intercalated thin limy 

sandstone and quartzite beds 10. 

Fossil collections 

Listed on toble I 

Break in section due to major 

structure or cover 

J 

Unit listed on table 

Shoshone 

Mesa 

FEET 

-o 

~ 

~ 

Thin- to thick-bedded limestone 

and sandy limestone, intercalated thin limy sandstone 

and quartzite beds 

laminated silty and clayey 

limestone to limy argillite 

laminated to thick-bedded 

calcitic dolomite 

z z 

z 

Plant fossils 

s s 

s 

Sinuate markings on stratification planes in laminated argillite, probably worm trails and 

borings 

Mostly covered 

Unconformity 

Queried where inferred 

u 

Arbitrary break in section 

500 

1000 

Grouse Canyon section measured by E. N. Hinrichs and A. B. Gibbons, 1959 

FIGURE 328.2.-Composite stratigraphic section of Eleana formation and equivalent strata in Nevada Test Site and 

vicinity. A-J are major lithologie units. 
SHORT PAPERS IN THE GEOLOGI•C AND HYDROLOGfC SCIENCES, ARTICLES ~~ 9 3-4 3 5 D-107 

AGE AND CORRELATION 

The age of the Eleana formation, based on stratigrn.phic position and fossil evidence, is considered to be 

Mississippian and Early Pennsylvanian (fig. 328.2, 

tables 328.1 and 328.2). The basal part of the Eleana 

may be ns old as Late Devonian. The formation overlies the Devonian Devils Gate ( ~) limestone 2 and underlies the Pennsylvanian and Permian ( ~) Tippipah limestone (fig. 328.2). Fossils collected from the Eleana 

formation are listed in table 328.1. 

2 Questionably corr.elnted by Johns·on and Hibbard (1957) with the 

t,vpe Devils Gate limestone in the Eureka area. 

TABl-E 328.1.-.Major lithologic ·units a11d fossil collections from Eleana formation and equivalent strata in Nevada Test Site and 

vicinity 

(.Fo~slls collrctcd hy E. N. Hinrichs,~. A. H. Gibbons, F. G. Poole, F. N. Houser, and P. P. Orkilrl; fossils identified by Helen Duncan, .T. 1'. Dutro, Jr., E. L. Yochclson W. J. Sando,:;. H. Mamay, Mackenzie Gordon, Jr., J. Steele Williams, C. VI. Merriam, Hobert Finks, and W. A. Oliver, Jr.] 

Formntlon and 

lithologic unit. 

Tippipnh limestone. 

.J 

I 

Position in 

Elean~t formntion unknown. 

Collection number 

(see fig. 328.2) 

2 

3 

4 

5 

6 

Collected south 

of Quartzite 

· Mounta.in 

section. 

Fossils 

Chonetes sp.; Composita? .sp.; Astartella? sp.; 

mytilacean? pelecypod; "Mourlonia" sp.; 

Straparollu.s (Euomphalus) sp.; nuculoid 

pelecypod; gastropod, indet; paralegocerid goniatite, genus and sp. indet. 

Schuchertella:? sp., Chonetes sp., lnflatia cf. 

I. inflata (McChesney), Schizophoria sp., 

Spirifer sp., Myalina sp., Sc~zodus sp. 

Echinoderm debris, indet.; bryozoan debris, 

indet.; stenoporoids, indet; Tabulipora?; 

rhomboporoids, indet.; Cystodictya?; hifoliate fistuliporoids; fenestrate cryptostomes, indet. 

Smooth spiriferoid like Composita or Jl.tfartinia; productoid, possibly a Setigerites. 

Pelmatozoan debris, indet.; corals, indet.; 

possible zaphrentoid coral; bryozoans 

represented by incrusting, small ramose, 

fenestrate, and pinnate forms. 

Lophophyllidium; corals, indet.; pelmatozoan debris, indet.; bryozoan fragments, 

indet.; gastropods, indet.; brachiopods, 

indet.; discoidal objects, possibly algal 

bodies. 

Strophomenid. brachiopod, genus indet., 

Setigerites? sp., leiorhynchid brachiopod, 

genus and sp. indet., Spirifer sp., Tylothyris sp., Eumetria sp., Zaphrentites sp., 

Amplexizaphrentis sp., pelmatozoan debris, Fenestella sp., Polypora sp., Cystodictya sp., ramose bryozoans, indet. 

Age and remarks 

E. L. Y ochelson reports that the brachiopods, 

pelecypods, and gastropods could be either 

Pennsylvanian or Permian. The cephalopod, 

according to Mackenzie Gordon, Jr., is of a 

ty~e indicative of Pennsylvanian age. 

Mackenzie Gordon, Jr., reports that the 

Spirifer in this collecti.on seems to be close to 

or identical with an undescribed form that 

occurs in the upper part of the Chain man 

shale. Available evidence suggests that the 

beds collected are of Late Mississippian age. 

Helen Duncan reports the stenoporoids with 

conspicuously moniliform walls indicate a 

post-Devonian age, but the .genera tentatively identified and the assemblage as a 

whole might occur throughout the Carboniferous and into the Permian. 

Mackenzie Gordon, Jr., reports that these fossils are Carboniferous forms, but the collection is too meager and poorly preserved to 

establish the precise age. If the producto d 

is a Setigerites, Early Mississippian age is 

indicated. 

Helen Duncan reports that Lophophyllidium 

ranges through the Pennsylvanian and Permian. 

Mackenzie Gordon, Jr., says this assemblage 

is of Early Mississippian age and probably 

represents the middle part of the series. 
D-108 GEOLOGICAL SURVEY RESEARCH 1 9 6 1 

TABLE 328.1.-Major lithologic 1tnits and fossil collections from Eleana formation and eqtlivalent strata in Nevada Test Site and 

vicinity-Continued 

Formation and 

lithologic unit 

Collection number 

(see fig. 328.2) 

Fossils Age and remarks , 

--------------------------------1--------------------------------

H 

G 

F 

E 

A 

Devils Gate(?) 

limestone or 

Nevada 

formation. 

7 

8 

Collected north 

of Grouse 

Canyon 

section. 

9 

10· 

Collected north 

of Grouse 

Canyon 

section. 

11 

12 

Leiorhynchid brachiopod, indet. 

Penniretepora sp.; orthotetid brachiopod, 

indet.; Spirifer sp. (molds and casts); 

P.unctospirifer? sp.; gastropod(?), indet.; 

pelmatozoau debris, indet.; fenestrate 

bryozoans, indet. 

Spirifer sp. (large); Spirifer sp. (small); 

bellerophontacean gastropod, indet.; 

Straparolltu; (Euomphal,us) sp.; Loxonema 

n. sp.; phillipsid trilobite; pygidium, 

indet.; bryozoan fragments, indet.; horn 

corals, indet.; pelmatozoan debris, indet. 

Crinoid columnals, iudet.; horn 

indet.; fenestrate bryozoans, 

euomphalacean gastropod, indet. 

Orthotetes? sp. 

corals, 

ii1det.; 

Trilobite cast, possibly a Griffithides? 

Pelmatozoan debris, indet. 

Pelmatozoan columnals and debris, indet.; 

brachiopod fragments, indet.; pelecypod 

fragments, indet.; branching bryozoan, 

indet. 

Possibly Mississippian in age. 

Do. 

Definite Mississippian aspect. E. L. Yochelson 

notes that the Straparollus is possibly S. (E.) 

snbplanus (Hall) and may indicate correlation 

with the Madison and(or) upper R.edwall 

faunas. 

Possibly Mississippian. 

Probable Mississippian age. 

----------------------------------------- 1-----------------------------------

13 

14 

15 

Compressed fairly stout vascular plant axis; A vascular land plant, and as such, is Middle 

evidence of two or three branch attach- Silurian or younger. 

ments. 

Trapezophyllum sp.; Disphyllum'? · sp.; 

Acrophyllmn'? sp.; horn coral, indet.; 

Favosites sp. (common); Alveolites sp.; 

Thamnopora sp. stromatoporoids; gastropod, indet.; Atrypa (large). 

"Cystiphyllum" sp.; Thamnopora sp.; echinoderm debris, indet.; crinoid columnals, 

indet.; Schizophoria'? sp.; "M artinia" sp.; 

spiriferoid brachiopod, indet. 

According to W. A. Oliver; Jr., the corals are 

definitely Devonian; most likely early Late 

Devonian in age. J. T. Dutro, Jr., reports 

that the large Atrypa is no younger than 

early Late Devonian. The age could be 

either :Middle Devonian or early Late 

Devonian. 

W. A. Oliver, Jr., reports that the corals could 

be either Silurian or Devonian; however, the 

structure of "Cystiphyllum" suggests Devonian species and the fossils are probably 

Devonian. J. T. Dutro, Jr., reports that 

the association of the brachiopods suggests 

a Middle Devonia·n age and a correlation 

with the Nevada formation. 
SHORT PAPERS. IN THE GEOLOGIIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-109 

TABLl~ 328.l.-l\1ajor litholO{Jic 'Units and fossil collections f'rom Eleana formation and equivalent strata in Nevada Test Site and 

vicinity-Continued 

Formntlon and 

lithologic unit 

Collection number 

(see fig. 328.2) 

Fossils Age and remarks 

Mercury 

limestone. 

l() Spin:je·r centronat1ts? ,,~inchell; P1·od1tctus 

scabriculus Martin; productids, indet.; 

spirifers, indet.; possibly Chonetes, possibly Rhynchopora; Syringopora cf. S. 

aculeata Girty; Syringopora; clisiophyllid 

fragments; caninoid horn coral fragments. 

C. W. Merriam, Helen Duncan, and J. Steele 

Williams report that this collection is 

probably Early Mississippian in age. 

-----------------------------·-------------·---------------------------------------------------

N nr..-ow Canyon 

lirneRtone. 

17 Linguloid brachiopods (Barroisella); fragments and spicules of a dictyospongid. 

According to Robert Finks dictyospongids 

reached their peak of development in the 

Late Devonian. .J. T. Dutro, Jr., reports 

that the brachiopod is common in Upper 

Devonian rocks and rare in younger beds. 

For these reasons, the age is suggested as 

possibly Late Devonian. 

T'he basnJ part of the Eleana may be as old as .Late 

Devonian becn.use it contains strata which are lithologically similnr to the upper part of the Devils 

Gn.te (?) limestone elsewhere, and because it is correlated with the Narrow Canyon limestone of comparable 

strn.tigrnphie position. The limy sandstone beds of 

unit A are simjhtr to those found in the upper part of 

the Devils Gn.te (?) 1 imestone of l\1iddle and Late Devonian a.ge in exposures to the south, suggesting that 

erosion in the Carbonate ''rash area may have begun 

before the end of Devils Gate(?) deposition elsewhere. 

:F'urthermore, the Narrow Canyon limestone, which is 

believed by the writers to be correlative with unit A 

and lower part of unit R on the basis of stratigraphic 

position, contn.ins a fauna indicating a Late Devonian (?) age (table 328.1 and fig. 328.2). 

Fossils from units G and I-I indicate a l\1ississippia.n 

age (table 328.1). Faunas from limestone beds of units 

I and .r indicate both a l\1ississippian and Pennsylvanian age. The difference in age assignments for collection 6 and the collection south of Quartzite Mountain 

(table 328.1) is not understood. These collections are 

"from 1 irnest:one units .about. 3 miles apa.rt and preliminary eorrelation inclieates that the f:tunas are from 

unit·, 1; however, sh·llct'u ml complexities may account 

for the anomalous position of either collection. 

l\1arine fn .. u.nn .. indicative of a Pennsylvanian age in 

the bas~tl part of the overlying Tippipah limestone 

establishes an up.per limit for the age of the Eleana. 

On the above basis, therefore, it is here proposed that 

the Eleana ranges in age at least from Early Mississippian to Early Pennsylvanian and it may be as old as 

Ln.te Devonian. 

A southeastward facies change from fine and coarse 

detrital strata of the Eleana formation in the northern 

part of the test site to an equivalent sequence of fine 

detrital strata and limestone at Narrow Canyon a.nd in 

the northern part of the Spring l\1ountains (about 20 

miles south of Narrow Canyon) suggests that the 

detrital strata represent the southeastern margin of an 

apron of clastic debris shed eastwai·d from the Antler 

orogenic belt of Roberts and others (1958) northwest 

of the test site. 

In the Carbonate 'Vash area (figs. :328.1 and 328.2) 

the basal unit of the Elen.na. formation may reflect the 

beginning of the Antler orogeny in this area. Units 

C~ F, and G are elmracterized by quartzite and conglome.rite that. may record a minimum of three distinct 

pulses or changes in ba.se level resulting in deposition 

of coarse detritus eastward. 

In view of the variations in thickn·e..ss and lithologic 

character of the units in the Eleana formation in the 

test site area it is understandable why comparable seetions have not been described in adjacent areas. Similar 

lithologies are known in the Eureka and Quartz Spring 

sections (fig. 328.1 and table 328.2), but specific units 

cannot be accurately correlated from one area to 

another. The lithic similarity of the Ca.rboniferous 

sequence in these areas is probably a result of comparable proximity to the Antler oroge.nic belt in central 

Nevada (fig. 328.1). On the othee hand, the Goodsprings area (table 328.2) a.nd the Pioche district are 

more distant from the orogenic belt., and hence in these 

areas the dominantly carbonate rock of the Carboniferous section may reflect grea.ter distance from the 

orogenic belt (fig. 328.1). 
D-110 

(f) 

::> 

0 

0::: 

LLJ 

u.. 

z 

0 

Ill 

0::: 

~ 

u 

iz 

z 

~ 

z 

0 

> LLJ 

0 

~ 

z 

~ 

> ....J 

>- (f) 

z 

z 

LLJ 

a.. 

z 

~ 

a: 

a.. 

u; 

(f) 

u; 

(f) 

~ 

Q) 

:0 

"0 

~ 

GEOLOGICAL SURVEY RESEARCH 19 61 

.... 

Goodsprings area, 

Nevada 

(Hewett, 1931) 

Quartz Spring area, 

California 

(McAllister, 1952) 

(Eroded) 

"OCil 

ca. Tihvipah limestone <I) C. 

Q; 

3: 

0 

....J 

Q; 

3: 

0 

....J 

::> Bird Spring 

formation 

2500± ft 

Monte Cristo 

limestone 

700± ft 

Sultan 

limestone 

600± ft 

1 Considered as Pennsylvanian(?) by McAllister 

(1952, p. 14, 25, 26). 

200± ft 

Rest Spring 

shale 1 

310± ft 

Perdido 

formation 

610± ft 

Tin Mountain 

limestone 

475ft 

Lost Burro 

formation 

1525 ft 

Hidden Valley 

dolomite 

(upper part) 

2 Lower part of Narrow Canyon limestone is considered Late 

Devonian(?) and basal part of Eleana formation may be Late Devonian 

Nevada Test Site Eureka area, Nevada 

(This report) (Nolan, Merriam, and 

Southern part Northern part Williams, 1956) 

Tippipah 

limestone 

(lower part) 

3500+ ft 

Ely 

limestone 

1500 ft 

Diamond Peak formation 

and Chainman shale 

7600 ft 

Eleana 

Mercury formation 2 Joana 

limestone 7700+ft limestone 

150+ ft 0-125 ft 

Narrow Canyon Pilot 

limestone 2 shale 

210ft 315-425 ft 

Devils Gate(?) Devils Gate 

limestone Devils Gate(?) limestone 

1400± ft limestone J 1200± ft 

Nevada formation Nevada formation 

1100+ ft 2500± ft 

Lone Mountain 

(unnamed) dolomite 4 

(upper part) 

' Tentatively assigned to Devils Gate(?) limestone. PreEieana erosion may have removed part or all of the 

Devils Gate(?). 

• Considered Early Devonian and/or Silurian (Nolan, Merriam, 

and Williams, 1956, p. 39). 

'!'ABLE 328.2.-Tentative correlation and thickness of Devonian, Mississippian, and Pennsylvanian formations in-~evada 

Test Site and nearby areas 
SHORT PAPERS IN THE GEOLOGJiC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-111 

REFERENCES 

Bull, S. H., 1907, A geologic reconnaissance in southwestern 

Nevada and eastern California: U.S. Geol. Survey Bull. 

308,218 p. 

Hewett, D. F., 1931, Geology and ore deposits of the Goodsprings quadrangle, Nevada: U.S. Geol. Survey Prof. Paper 

162,172 p. 

. Tohnson, M. S., and Hibbard, D. E., 1957, Geology of the Atomic 

Energy Commission Nevada Proving Grounds area, Nevada: U.S. Geol. Survey Bull. 1021-K, p. 333-384. 

McAllister, J. F., 1952, Rocks and structure of the Quartz Spring 

area, northern Panamint Range, California : California 

Div. Mines St)ee. Rept. 2G. 38 p. 

Nolan, T. B., Merriam, C. W., and Williams, ~r. S., 1956, The 

stratigraphic section in the vicinity of Eureka, Nevada: 

U.S. Geol. Survey Prof. Paper 276, 77 p. 

Roberts, R. J., Hotz, P. E., Gilluly, James, and Ferguson, H . 

G., 1958, Paleozoic rocks of north-central Nevada: Am. 

Assoc. Petroleum Geologists Rull., v. 42, p. 2813-2857. 

329. LAKE LAHONTAN STRATIGRAPHY AND HISTORY IN THE CARSON DESERT (FALLON) AREA, NEVADA 

By R. B. MoRRISON, Denver, Colo. 

The late Quaternary deposits of the southern Carson 

Desert, near Fallon, Nev., record the history of the 

fluctuaJions of Lake Lahontan and younger lakes in 

this intermontane basin. The Carson Desert is the sink 

for two of Nev~tda's largest rivers, the· Carson and 

I-Iumboldt, and contains an unustutlly detailed strnJigraphic record of lake rises, recessions, and desiccations 

in response to Quaternary climatic changes. 

The lnJe Quaterna.ry deposits (exclusive of local vol-

. cn.nic units) are divided into seven formations and 

several soils. These units are given new stratigraphic 

names, which are introduced, defined, and briefly described, from oldest to youngest, be.low (see fig. 329.1). 

PAIUTE FORMATION 

This unit consists of at least 40 feet of a.lluvial and 

colluvial grttvel of later Pleistocene age·. It overlies 

andesitic a.nd basaltic lavas of Pliocene and early 

Pleistocene(~) age with pronounced unconformity and 

underlies the pre-Lake Lahontan soil and the earliest 

deposits of Lake Lahontan (Eetza formation) with 

slight or no disconformity. It is named for Paiute 

'''ash, and its type locality is an exposure along the 

middle part of this wash (stratigraphic section 56, in 

~{orrison, 1959). It is exposed locally, above :3,960 feet 

n.H.itude, on piedmonts and in highlands. 

PRE-LAKE LAHONTAN SOIL 

This is a very mature calcic Brown soil, developed 

on the Paiute formn,tion and older rocks and overlain 

by the Eetza formation with slight or no disconformity. 

Its type locality is the same as that for the Paiute formation. This soil consists of a. reddish-brown, clayey 

oxide (B) horizon as thick as a foot, over a white, 

strongly en lcareous ( Cc:a) horizon genera,lly 4 to 8 feet 

thick. It is exposed ·locally, above 8,960 feet nlt.itude, 

on piedmonts and in highlands. 

LAHONTAN VALLEY GROUI' 

This unit, of late Pleistocene age, consists of lacustrine sediments deposited in Lake Lahontan and 

interfingering and immediately overlying subaerial 

sediments. The group is named after Lahontan Valley, its typo area., which is a. part of the Carson Desert. 

It is divided into the following five formations on the· 

basis of lithologic differences due to two ma.jor alternations from ma.inly deep-lake to subaerial and shallowlake sediments: 

a. Eetz.a jm·1nation.-This formation, the oldest in the 

Lahontan Valley group, consists of as much as 

90 feet of lacustrine gravel to clay and tufa. It 

is exposed only in highlands above 3,950 feet 

altitude. The Eetza. overlies the pre-Lake Lahontan soil and older units with slight or no 

disconformity and conformably underlies the 

'\Vyemaha formation. It is namE~d for Eetza 

~lountain, and the type locality is the upper paM; 

of the central gulch in this mountain. This formation is locally divisible into two tongues separated by a. tongue of alluvium and colluvium of 

Eetza age, which bea.rs a very weak soil. The 

· lower tongue extends as high as the highest La.ke 

Lahontan shoreline, 4,380 feet altitude, and the 

upper tongue reaches about 4,340 :Eeet. altitude; 

the intervening subaerial tongue ha.s been noted 

as low as about 4,065 feet altitude. 

b. TVyenwha formation.-This unit comprises eolian 

sand and alluvium, which reach the lowest parts 

of the basin floor and intertongue with shallowJake deposits of sand to clay. lV[ost of the for-
D-112 GEOLOGICAL SURVEY RESEARCH 19 61 

Subaerial deposits, soils, Lacustrine deposits and 

and disconformities in- inferred lake fluctuations 

dicating lake recessions ---·- ------~ 

TIME 

]{ 

Q) 

c: 

Q) 

£ 

Ill 

'Q) 

a: 

2 

«< 

...J 

I. 

I 

t 

Q) 

E 

:;: 

c:: 

.s 

c: 

0 

.s::. 

«< 

....J 

Q) 

.X 

«< 

....J 

,-A---_.---------, 

ALTITUDE OF LAKE LEVEL, IN FEET 

0 

0 

N 

'<t 

0 

0 

~ 

Fallon formation 

c:: 

:8::::-

«1 «< E ·.:: ... Q) 

0 «< -..a 

Ill ::::l Q) Ill 

.X>. «1-

...J c: c::·ro 

.~ E -o .._, 

.E 

c: 

0 

:;: 

«< 

E 

.E 

«< 

.s::. 

«< 

E 

Q) 

>. 

~ 

c 

Q) 

c: ·e 

0 

a. 

Paiute formation 

(subaerial) 

0 

0 

ao 

('t') 

0 

0 

10 

('t') 

I 

I 

\ 

I 

0 

0 

'<t 

('t') 

a. 

::::l 

e 

00 

>. 

..!!! 

-ro 

> 

c: 

«< 

c 

0 

.s::. 

«< 

...J 

FIGURE 329.1.-Stratigraphic record of the fluctuations of Lake 

Lahontan and younger lakes in the Carson Desert. U, upper 

part ; M, middle part ; and L, lower part of a lacustrine or 

glacial unit; lc, lake cycles; numbers refer to lake cycles. 

mation lies conformably between the Eetza 

formation and middle Lake Lahontan soil, but 

some eolian sand extends higher than the highest 

altitudes reached by the Eetza and lies on older 

units. It is named for 'Vyemaha. Valley, at 

the western end of which its type area (site of 

stratigraphic sections 42h, 42c, 43, 43a, 43b, 44, 

44a, and 45, in :Morrison, 1959) is situated. This 

formation, widely exposed above 3,965 feet altitud.e, is as much as 100 feet in exposed thickness 

and probably is locally more than 150 feet thick 

in the subsurface of the basin interior. 

c. 11! iddle Lake Lahontan soil.-This is a mature calcic 

Brown soil that conformably overlies the youngest subaerial beds of the vVyemaha formation and 

underlies the Sehoo and Indian Lakes formations 

with slight or no disconformity. It is intercalated with, but not a part of, the Lahontan 

Valley group. Its type locality is the site of 

stratigraphic section 34, in l\1orrison, 1959, in 

Churchill Valley. This soil has a slightly clayey, 

brown oxide (B) horizon 1 to 11j2 feet thick, 

over a. strongly calcareous ( Cca) horizon 2 to 4 

feet thick. It is exposed locally above 3,920 feet 

altitude. 

d and e. Sehoo and Indian Lakes formations.-These 

are intertonguing units, both of which overlie 

the 'Vyemaha formation and the middle Lake 

Lahontan soil with slight or no disconformity, 

and underlie the Turupah formation with local 

disconformity. The Sehoo formation is entirely 

lacustrine; the Indian Lakes formation is predominantly subaerial. 

The Sehoo formation consists of three tongues 

of lacustrine gravel to clay and tufa, separated 

by tongues of the Indian Lakes formation. Each 

tongue is locally differentiated as a member of 

the formation and records a separate lake cycle 

of Lake Lahontan. The lower tongue (lower 

member) extends to 4,370 feet altitude, within 

10 feet of the highest Lahontan beach; the middle 

tongue, the dendritic member (named after a 

characteristic tufa), extends to as high as 4,180 

feet altitude; and the upper tongue (upper member) extends to a maximum altitude of about 

3,990 feet.' The type area for this formation 

is the same as that for the 'Vyemaha formationthe western end of "T yemaha Valley, near Sehoo 

:Mountain, whence the formation is named. This 

formation is widely exposed and is as thick as 

96 feet. 

The Indian Lakes formation consists of alluvium, collu,·ium~ and a little eolian sand and 

shallow-lake sediments, as much as 15 feet. thick. 
SHORT PAPERS IN THE GEOLOG:OO AND HYDROLOGIC SCIENCES, ARTICLES 29,3-435 D-113 

It also has three tongues. The lower one is intercalated between the middle Lake Lahontan 

soil and the lower tongue of the Sehoo formation; the middle one is intercalated between the 

lower and middle tongues of the Sehoo, to at 

least as low as 3,990 feet altitude; and the upper 

tongue is intercalated between the middle and 

upper tongues of the Sehoo, to at least as low as 

3,900 feet. The middle tongue bears an incipient soil, and the upper tongue a very weak soil. 

The type locality is the westerit part of the Indin,n Lakes area, SE%, T. 20 N., R. 29 E. and 

SWl)t, T. 20 N., R.· 30 E., where two ancient 

river-distributary channels are composed of alluvial sand of the formation. 

f. Tu'r?.tJ)ah formation.-This unit consists of as much 

as 30 feet of eolian sand and local alluvium 

overlying the Sehoo and Indian Lakes formations 

with local disconformity and conformably underlying the post-Lake Lahontan soil and Fallon 

formation. This unit and a widespread coeval 

disconformity recording pronounced deflation 

extend to lowest parts of the basin floor. The 

type locality is exposures of eolian sand and alluvium of the formation along the northwestern 

edge of Turupah Flat, sees. 29 and 33, T. 18 N., 

R. 30, from which the formation is named. 

POST-LAKE LAHONTAN SOIL 

This is a submature Gray Desert soil, developed on 

the Turupah formation and older units, but overlain 

by the Fallon formation with slight or no disconformity. It has a top "vesicular" horizon about 3 inches 

thick, next, a light-brown, light brownish gray, or brown 

B horizon about 5 inches thick, over a light-gray to 

light brownish gray, moderately to weakly calcareous 

Cca horizon 6 to 14 inches thick. Its type locality is an 

exposure (site of stratigraphic section 16, in Morrison, 

1959) about lj3 mile east of the northeast corner of the 

S-Line Reservoir. The upper boundary of this soil 

is proposed as the Pleistocene-Recent boundary in the 

Great Basin_ region (Art. 330) . 

FALLON FORlLATION 

This formation, a maximum of 36 feet thick, comprises subaerial sediments (eolian sand, alluvium; and 

colluvium) and intertonguing shallow-lake sediments of 

Recent age. It overlies the Turupah formation and 

post-Lake Lahontan soil with slight or no disconformity. Its type locality is the lowlands of the Carson 

Desert near Fallon, whence it· takes its name. This 

formation is locally subdivided into lower and upper 

members at altitudes below or only slightly above the 

maxima of the post-Lahontan (Fallon) lakes. The 

lower member. comprises two lacustrine tongues, separated and overlain by subaerial tongues; it bears a very 

weak soil. The upper member comprises three lacustrine tongu~, likewise separated and overlain by subaerial tongues. The lacustrine tongues record five postLahontan lake cycles whose maxima (oldest to youngest) were at. altitudes of 3,950, 3,!~30, 3,922, 3,919, and 

3,919 feet. Each tongue extends to the high shoreline 

of the lake cycle it records. Only the first two of these 

shorelines are well marked by rnorphologic features. 

The intervening subaerial tongues extend, to or nearly 

to, the lowest parts of the low lands, indicating complete 

or nearly complete desiccation. 

CONCLUSIONS 

The general conclusions on lake history from these 

deposits ar~ as follows: 

Pre-Lake Lahontan history is fragmentary, but Lake 

Lahontan and post-Lake Lahontan history is fairly 

complete. A lake older than Lake Lahontan is suggested by a single exposure of lacustrine sediment. The 

Paiute formation and overlying pre-Lake Lahontan 

soil record an ensuing long interval of lake recession 

or desiccation. 

The early deep-lake period of Lake Lahontan is recorded by the Eetza formation (fig. 329.1}. This period consisted of two lake cycles and an intervening lake 

recession: Lake Lahontan first rose until it reached its 

maximum level of 4,380 feet altitude; it receded briefly 

to at least as low as 4,065 feet, and then it rose again 

to about 4,340 feet altitude. In middle Lake Lahontan 

time, recorded by the Wyeinaha formation and middle 

Lake Lahontan soil, the basin intermittently was dry 

and held shallow lakes. During late Lake Lahontan 

time, when the Sehoo and Indian Lakes formations were 

deposited, the lake had 3 maxima and 2 recessions; 

first, it rose· to 4,370 feet altitude, then dropped at 

least to 3,990 feet, then rose to 4,190 feet, then dropped 

at least as low as 3,900 feet, and then rose a last time 

to 3,990 feet altitude. 

The Turupah formation re:cords the stark aridity of 

the early part of a warm interval that is correlated 

with the altithermal age of Antevs ( 1948, 1952, 1955)-

a time when the Carson Desert generally was completely 

dry and its lowlands were severely deflated. The postLake Lahontan soil attests to somewhat increased 

precipitation, plant cover, and cessation of wind erosion 

during the later part of this warm interval. 

The Fallon formation fo)['med during the last 3,500 

or 4,000 years-the Recent epoch in the Great Basin 

region (Art. 330; Morrison and others, 1957). It records five intervals that were somewhat wetter than 

now, when small lakes with maximum depths successively (oldest to youngest) of about 90, 70, 57, 40, and 
D-114 GEOLOGICAL SURVEY RESEARCH 1 9 6 1 

30 feet occupied parts of the basin floor. The first 

lake maxim urn occurred about 3,500 years ago, the last 

about 100 years ago. After each lake maximum was 

a complete, or nearly complete, lake recessi9n-indicating climate like that of the present or somewhat 

more arid. The longest, driest, and warmest recession 

was between the 2nd and 3rd post-Lahontan lakes, when 

the basin generally was completely desiccated and a 

very weak soil formed. 

These deductions concerning the lake history do not 

support J. C. Jones' (1925, 1929) interpretation that 

Lake Lahontan had only a single lake cycle starting 

a mere 2,000 or so years ago. They agree (fig. 329.2), 

however, with most of Russe1l's (1885) and Antevs' 

(1945, 1948, 1952, 1955) conclusions. Lake Lahontan 

had multiple maxima during both early and late 

Lake Lahontan times, supplementing both Russell's 

and Antevs' interpretations. The lake dried completely in mid-Lake Lahontan time, contrary to Ante\--s' 

interpretation but in line with Russell's. The lake 

reached its highest level in early Lake Lahontan time, 

as Antevs inferred, contrary to Russell's conclusion. 

REFERENCES 

Antevs, E. A., 1945, Correlation of Wisconsin glacial maxima, 

in Problems in geology and geophysics, Daly volume, 

243-A: Am. Jour. Sci., p. 1-39. 

---1948, Climatic changes and pre-white man, in The Great 

Basin, with emphasis on glacial and postglacial times : 

Utah Univ. Bull., v. 38, no. 20, p. 16&-191. 

---1952, Cenozoic climates of the Great Basin: Geol. 

Rundschau, v. 40, no.1, p. 94-108 (in English). 

---1955, Geologic-climatic dating in the west: Am. 

Antiquity, v. 20_, no. 4, pt. 1, p. 317-335. 

.Jones, J. C., 1925, The geologic history of Lake Lahontan, in 

Quaternary climates: Carnegie lost. Washington Pub. 352, 

p. 1-50. 

--1929, Age of Lake Lahontan : Geol. Soc. America Bull., 

v. 40, no. 3, p. 533-540. 

Morrison, R. B., 1959, Stratigraphic sections, well logs, and 

soil-profile sections in the southern Carson Desert near 

Fallon, NeYada: U.S. Geol. Survey open-file report 470. 

Morrison, R. B., Gilluly, James, Richmond, G. M., and Hunt, 

C. B., 1957, In behalf of the Recent: Am. Jour. Sci., v. 255, 

no. 6, p. 3~-393. 

Russell, I. C._, 1885, Geological history of Lake Lahontan, a 

Quaternary lake of northwestern Nevada: U.S. Geo~. Survey Mon. 11, 288 p. 

Russell (1885) Antevs (1945, 1948, 1952) Morrison 

(this paper) 

..c: 

u 

1'3 

Q) 

.c 

Elevation above 1882 level of 

Pyramid Lake (3867 feet alt) 

Present time 

Post-Lahontan arid period 

Second rise of 

Lake Lahontan 

(upper lacustral clay) 

Inter-Lahontan period 

of desiccation 

(medial gravel) 

First rise of Lake Lahontan 

(lower lacustral clays) 

Pre-Lahontan arid period 

Altithermal "age" 

"Dendritic Lake" 

w 

~ 

5 

0 

~ "Thinolite Lake" < 

0:: 

>- a.. 

"Lake Lahontan 

proper" 

Elevation above 1882 level of 

Pyramid Lake (3867 feet alt) 

1-

0:: 

~ w 

0 

Altitude abOve sea level, 

in feet 

Fallon time 

Wyemaha time 

Eetza time 

Cocoon interval 

Paiute time 

.F'IOURE 329.2.-Comparison of interpretations of Lake Lahontan by Russell, Antevs, and Morrison. 

, .. ~· 
• 

SHORT PAPERS IN THE GEOLOGilC AND HYDROLOGIC SCIENCES, ARTICLES 293-~35 D-115 

330. A SUGGESTED PLEISTOCENE-RECENT (HOLOCENE) BOUNDARY FOR THE GR:EAT BASIN REGION, 

NEVADA-UTAH 

By R. B. MoRRISON, Denver, Colo. 

Establishment of a world-wide boundary between the 

Pleistocene and Recent (Holocene), though eventually 

desirable, probably still is premature. Much more 

stratigraphic research is needed before a boundary can 

·be established, even on a continental basis, that will be 

pragmatically sound for geologists and archaeologists 

working in such different terrains as, for ex~mple, 

areas of Arctic glaciation, of midlatitude Cordilleran 

glaciation, margins of continental glacial drift, desert 

lake basins, and seacoasts. It probably will be most 

practical to establish this boundary independently (but 

within a restricted time range) in regions of unified 

· terraii1. The Great Basin of the western States is 

such a region. , 

IIunt ( 1953) has proposed, for the Rocky MountainGreat Basin region, that this boundary be placed at a 

widespread strntigraphic break that marks what is 

commonly known as the thermal maximum, climatic 

optimum, or altithermal interval. He noted that this 

break in the late Quaternary deposits is indicated by 

an unconformity, above and below which are lithologically distinct deposits. During the interval represented by the unconformity, many Pleistocene 

mammals, such as elephants and camels, became 

extinct. This proposal has merit, in spite of several 

drawbacks: the unconformity, although widespread, is 

only locally recognizable; it represents a variable timespan, probably between a few hundred and ten thousand or more years in duration; and it also is, at least 

locally, significantly time-transgressive. In additio;n, 

the extinction of mammals seems to have started In 

some areas considerably before the interval represent~d 

by the unconformity. Certain mammals became extinct during Cary time in Nebraska, for example. 

Ideally, the boundary should be selected and defined 

to meet the following stratigraphic requirements: 

1. It should be derived from a type rock-stratigraphic 

sequence, representative of the region, whose rock 

units have been well studied and classified. The 

boundary should not be defined wholly or mainly 

on inferred climatic or depositional history, or 

on time-stratigraphic, climastratigra:r>hic, biostratiO'raphic, or geologic.:.time units that are not 

themselves defined by rock-stratigraphic or soilstratigraphic units. 

2. The boundary should be marked by a prominent, 

widely traceable and mappable lithologic discontinuity within the sequence. 

3. The boundary should be as nearly time-parallel as 

possible. 

Fortunately, a nearly ideal marker unit for the 

boundary is available within the time interval that 

Hunt proposed-one that is applicable to all types of 

lithogenetic sequences (lacustrine, glacial, alluvial, colluvial, and eolian) throughout the Great Basin region. 

This unit is a submature soil that is distinct from other 

soils of late Quaternary age. This soil has been noted 

in the late Quaternary successions in the Lake Bonneville area (Art. 333; Bissell, 1952 and written communication, 1960), in the Lake Lahontan area (see 

below), in the Sierra Nevada (Art. 332), and in the 

Rocky Mountains (Richmond, 1~60, and in press), and 

reconnaissance studies indicatt3 that it is essentially 

continuous throughout this region and adjoining ones 

(Leopold and Miller, 1954), more so than any/'of the 

older soils. 

The stratigraphic relations of this soil have been most 

precisely determined in a part of the area of late Pleistocene Lake Lahontan, the Carson Desert basin, 

Nevada, where it is called the post-Lake Lahontan soil 

(Art. 329). This basin is the sink for two of the largest 

rivers of the northwestern Great Basin; it contains an 

especially detailed stratigraphic record of .post-Lake 

Lahontan time, and it also is the only area in''the Great 

Basin where Recent (Holocene) sediments ··have been 

intensively studied and classified into rock-stratigraphic 

units. The post-Lake Lahontan sequence here is as 

follows: 

Post-Lake Lahontan deposits in. the Carson Desert, near 

Top. Fallon, Nev. 

Fallon formation: !tf:i~~":t~::! 

Upper member : (feet) 

Three tongues of shallow-lakE~ sand, clay, and tufa, 

separated and overlain by eolian sand and alluvium -------------------·--------------------- 15 

Local erosional disconformi ty ; very weak soil. 

Lower member: 

Two tongues of shallow-lake gravel, sand, clay, and 

tufa. separated and overlain by eolian sand and 

alluvium ----------------·---------------------- 21 

Slight or no disconformity. 
D-116 GEOLOGICAL SURVEY RESEARCH 1 9 6 1 

Post-Lake Lahontan deposits in the Carson Desert, near Fallon, 

Nev.-Continued 

1llaxi11111m 

thicknel3s 

Post-Lake Lahontan soil: (feet) 

A submature Gray Desert soiL___________________ 1. 5 

Turupah formation: 

Eolian sand and local alluvium, to lowest parts of 

basin floor_____________________________________ ao. 

Disconformity, recording widespread deflation, to lowest 

parts of basin floor. 

Sehoo formation (younger sediments of Lake Lahontan) : 

Lacustrine sand, clay, and tufa in basin interior; 

gravel, sand, and tufa in highlands; extends as 

high as 510 feet above lowest part of basin floor__ 96 

The Sehoo formation is inferred to record the final 

lake cycles of Lake Lahontan. The overlying disconformity, Turupah formation, and post-Lake Lahontan 

soil record a long interval of generally complete desiccation of the Carson Desert, that is correlated with the 

~tltithermal age of Antevs ( 1948, 1952, 1955). The 

Fallon formation records 5 post-Lahontan shallow-lake 

~ycles, that rose successively about 90, 70, 57, 40, and 

30 feet above the lowest part of the Carson Sink. 

During the intervening hike recessions the basin became nearly or entirely dry. The longest and most 

pronounced desiccation was between the first and second lake cycles, "·hen the only discernible (albeit very 

weak) soi 1 development in Fallon time took place. 

In the author's opinion the Carson Desert should be 

designated as a type area for Recent (Holocene) deposits of the Great Basin, and the Pleistocene-Recent 

boundary (the Pleistocene-Holocene boundary of 

European usage) should be placed at the top of the 

post-Lake Lahontan soil. This soil not only is the most 

distinctive and widely traceable stratigraphic unit in 

the Recent deposits of the Lake Lahontan area, but its 

correlative soils in the alluvial, eolian, and glacial deposits of the Great Basin and adjoining areas (for 

example, the Sierra Nevada and 'Vasatch-Rocky Mountains) are similarly distinctive. The post-Lake Lahontan soil and its correlatives are known, from archaeologic and radiocarbon dating, to have formed within a 

span of probably less than 1,000 years in later altitherrnal time. 

This soil-forming interval ·was induced by a climatic 

change that probably was essentially synchronous over 

the entire Great Basin region. Thus, the post-Lake 

Lahontan soil is assumed to be nearly time-parallel over 

this region. Also, because it formed during a comparatively brief interval, it is a relatively precise timestratigraphic marker-more so than any of the younger 

sedimentary units or unconformities known in the 

region (other than a few ash beds that ·occur only 

locally). 

REFEREN-CES 

Antevs, E. V., 1948, Climatic changes and pre-white man, in The 

Great Basin, with emphasis on glacial and post-glacial 

times: Utah Univ. Bull., v. 36, no. 20 (Bioi. Serv., v. 10, 

no. 7), p. 168-191. 

~. - 1952, Cenozoic climates of the Great Basin : Geol. Rundschau, v. 40, no. 1, p. 94-108 (in English). 

--1955, Geologic-climatic dating in the west (U.S.) : Am. 

Antiquity, v. 20, no. 4, pt. 1, p. 317-335. 

Bissell, H .. J .. 1952, Stratigraphy of Lal~e BonneYille and associated Quaternary deposits in Utah Valley, Utah [abs.] : 

Geol. Soc. America Bull., v. 63, no. 12, pt. 2, p. 1358. 

Hunt, C. B., 1953, Pleistocene-Recent boundary in the Rocky 

Mountains region: U.S. Geol. Survey Bull. 006-A, p. 1-25. 

Leopold, h B., and Miller, .J. P., 1954, A postglacial chronology 

for some alluvial valleys in "ryoming: U.S. Geol. Survey 

Water-Supply Paper 1261, 90 p. 

Hichmond, G. M., 1960. Glac-iation of the east slope of Rocky 

Mountain National Parle Colorado: Geol. Soe. America, v. 

71, p. 1371-1382. 

--Quaternary stratigraphy of the La Sal Mountains, Utah: 

U.S. Geol. Survey Prof. Paper 324 (in press). 

331. HYDROTHERMAL ALTERATIO}\f OF ROCKS IN TWO DRILL HOLES AT STEAMBOAT SPRINGS, WASHOE 

COUI\TTY, NEVADA 

By Guol\IUNDUR E. SIGvALDASON and DoNALp E. 'VHITE, 1\t[e.nlo Pa:rk, Calif. 

Steamboat Springs, in southern Washoe County, 

Nev., has been well known to economic geologists since 

the early studies on the metal-bearing spring deposits 

by Le Conte ( 1883) and Becker ( 1888, p. 331:--351). 

The geology of Steamboat Springs has been reviewed 

by Brannock and others (1948, p. 211-216) and the 

thermal activity and hydrothermal alteration have 

been summarized by White (1955, p. 103-104, 110-113; 

1957, p. 1639-1647). This report contains results of 

X-ray and. other mineralogical studies of hydrothermally altered rocks found in two drill holes at Steamboat Springs. 

• 
SHORT PAPERS IN THE GEOLOGJIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-117 

DRILL-HOLE GS-1 

Drill-hole GS-1 is on the active Low Terrace of 

Steamboat Springs near the southern end of the thermal n.rea. Some dfttn. concerning the hole are shown 

on figure 331.1, and chemica.l compositions of fresh and 

a..lt:ered rocks are shown by table 331.1. 

The degree of a] teration in drill-hole GS-1 is determined by depth, original rock type, and relation to 

permeable channels. The mineral most generally altered is hornblende, follmYcd by biotite and calcic plagioclase. Quartz remains unaffected and !{:-feldspar 

and sodic plagioclase appear to be metastable under 

~tll the conditions affecting the rocks dri1lled. Some 

neady -fresh gTandodiorite OCTlH'S near the Sttrface. Andesit-ic tuff breccia, originally consisting entirely of 

suscept·ible ferromagnesian minerals, calcic plagioclase, 

a,nd glass, has undergone complete alteration. The 

most intensely altered granodiorite lies immediately 

below n, dike of andesitic tuff breccia and i1ear faults 

and fraehn·es at depths of 270 and 364 feet. 

Estimated mineralogical composition is shown 

· gra.phically on figure 331.1. Straight lines connect 

points where the mineralogy was determined; however, 

aettml mineral compositions between points of observation are known to differ greatly from compositions 

implied by these lines.. Small quantities of pyrite, 

pynhotite, stibnite, and .calcite are not plotted. 

The dominant hydrothermal minerals are four species of clay. l\1ontmorillonite is most abundant in the 

altered andesitic dike (fig. 331.1). The spacing of the 

basal X-ray reflection of this material in air-dried state 

ranges frmn 12 to 15 A. The greater spacing results 

from calcium and magnesium in the interchangeable 

positions of the montmorillonite lattice, and the lesser 

spacing from sodium in the interchangeable position. 

Kaolinite is the dominant mineral in the most intensely altered and leached parts of the rock penetrated 

in the drill hole-, but is present only in small amounts 

where alteration is sli;ght.. 'V"here kaolinite is a major 

component, it is usually accompanied by N a-1(-montmorillonite; where kaolinite is a minor component, it 

occurs with Ca-Mg-montmorillonite. 

Two types of chlorite were detected. One is a minor 

component;· replacing biotite. The second is abundant 

in and near fractures at depths of 250 to 300 feet; it 

does not have X-ray reflections at 14 and 4.7 A as do 

most chlorites, and its lattice collapses at relatively low 

temperatures. H is thus similar in some ways to kaoTA m~J~ :~:31.1.-A nalyses of hydrothermally altered rocks of drill-hole GS-1 compared to fresh rocks 

[In percent; analyzed by rapid methods by L. Shapiro, 11. F. Phillips, K. White, S.M. Berthold, and E. A. Nygaard] 

Fresh rocks Rocks in drill-hole GS-1, and depth, in feet 

Granodio- Andesite Opaline Granodio- Grnnodio- Tuff-breccia, Tuff-breccia, Gr:modio- Granodio- Granodiorite west of at Steam- sinter, 2 rite, 14 rite, 63 173 192 rite, 259 rite, 312 rite, 364 Low 'l'ermce boat Hills 

--------------------·-------------1-----1-----------------1-----

Constituent: 

8102-------------------------- 65.6 59.3 92.1\ (i5. 4 (\4. 6 57.3 54.7 66.2 67.5 (jl,{j 

AhOa------------------------- 16.5 16.8 1.0 !G. 2 16.3 17.4 17.3 12.8 16.8 15. {j 

FoO •. ------------------------ 2.1 2. 4 . 14 1.3 2. (j !i. 5 8. 4 8. 4" 1.8 5. 4 

Fc203 •----------------------- 2. 2 3. (j . 23 3. 0 2. 2 1.2 1.1 i\1gQ _________________________ 1.7 3. 0 . 07 l.(j ].(\ 1.3 1.4 1.2 1.1 1.0 

CaO .. ------------------------ 3. 2 !i. 7 . 36 4. 2 4. 4 1.5 1.4 1.0 3.3 2. 2 ·.\la20 _________________________ 3. {j 3. 6 . 41 3. 8 3. 6 . 41 . 58 1.3 3. 5 1.2 

K20-------------------------- 2. 9 2. 2 . 21 2. 8 2. 9 2.1 1.8 2. 4 3. 1 3. 0 

1'102------------------------- . 55 . 62 . 04 . 51 .68 . 89 . 88 . 42 . 50 .54 

P206-------------------------- . 15 .16 . 02 . 14 . 34 . 24 . 25 .14 . 14 .11 

1\>tno _________________________ . 06 . 20 . 42 . 04 . 20 .12 . 06 . 34 . 04 .10 

"002-------------------------- . 0\) ------------ <. 05 <.05 .36 .09 .07 . 27 <.05 1.1 

8---------------~------------- . 00 ------------ . 00 . 01 . 02 1.9 4. 5 . a~· . 25 3. 0 

lT20+ _________________________ . 50 . (iO 5. 2 1.0 . 93 11.7 10.0 4. 2 1.2 7.0 

IJ~O- ------------------------- . 05 

'l'otnlns reported ___________ 99.2 99.2 100.8 100. I 100.7 101.45 101.34 100.3 100.4 101.9 

l.ess 0 for s __________________ -·---------- ------------ ---------- -------------- -------------- . 95 2. 25 .2 .1 1.5 

'rotaL ______________________ 99.2 99.2 100.8 wo.I 100.7 100.5 99. 1 100. I 100.3 100.4 

Spcclfl~ gr·avlty (powder) _________ 2. 69 2. 76 2. 11 2. 72 2. 70 2. 4!i 2. 49 2. n8 2. 66 2. ()2 

Specific gravity (lump) ___________ 2. 62 2. 54 l. 79 2. 59 2. (\4 1.83 1. 90 2. 20 2. 54 2.12 

Prominent hydrot.hcrmnl mincrnls ....•.•..... ________________ ............................... ------------ Opal (i1

.-linor (Minor Kaolinite, Chlorite, Chlorite, Kaolinite, Kaolinite, 

clays). clays, montmoril- kaolinite, kaolinite, (chlorite, montmorilMn-calcitc). \onite, montmoril- montmorll- illite, \onlte, 

chlorite, lonitc, lonitc, pyrite). pyrite, 

pyrite. pyrite. (pyrrhotite, (calcite). 

calcite). 
TEMPERATURE, oc 

20 40 60 80 

0 

100 _1 140 160 180 

50~------+--------r----~~------~r-------~~----,_-------r------~ 

I Bottom-hole temperatures obtained 

100 as drilling progressed 

150 

Chloride content of to: of water II I I I ~ indicated depth 

.... 

LLI 

LLI 

LL. 

CONDENSED 

LOG 

Opaline sinter 

Alluvium 

UNCONFORMITY 

Granodiorite, 

some 

weathering 

near top; 

pyrite and 63 

some stibn ite 

below 50 feet 

Fault 

157 

Andesitic tuffbreccia, 173 

probably 178 

intrusive 184 

~ 200 

41/\ 

192 

column when drill hole was at ~ 

;~ 

J: 

.... 

a.. 

LLI 

c 

250 k" . t N Thermistor temperature measure- ~ 

Fault 211 

213 

Granodiorite; 

pyrite and 

pyrrhotite 

ault zone, 

some tuffbreccia 

fragments 

271 

ments in water column when 3' hole was 365 feet deep ~-o.t-+----4---l 

Gr:~~~;~~~~e, 312 

3001 I I J1 

CHLORIDE CONTENT. IN PARTS PER MILLION 

altered but 

moderately 

fresh in places; 

nvrit'! and 

IOtite 

0 

~ 

·c:. 

g 

"§ 

s 

c: 

0 

~ 

APPROXIMATE PROPORTIONS OF 

PRINCIPAL MINERALS 

20 40 60 80 

Opaline sinter and clastic minerals 

Granodiorite, partly weathered 

Chlorite 

Ql 

Ill 

ftl 

u 

0 

"io 

ftl 

1L 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

...1 

Ql 

Ill 

ftl 

u 

0 

J: 

1:: 

0 

Ql 

Ill 

ta 

u 

0 

J: 

a~t: Ill 0 ta 

-u--o 

0 0 c: J:IIIIV 

1:: c: 0 0 

:;:; 

0 

Q. 

0 

c. 

i 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

: 

I 

I 

I 

I 

I 

~ 

c 

2 

Ill 

c: 

0 

(.) 

~ ftl 

::J 

0 

"ON 

Ql ... En; 

::J ::J 

~0 

IV 

~ ta 

::J 

r::r 

100 

FIGURE 331.1.-Data from drill-hole GS-1, Low Terrace, Steamboat Springs, Nev. Straight lines arbitrarily drawn between points of obsei'vation. 

1" 

? 

........ 

........ 

00 

0 

t>:l 

0 

tot 

0 

0 

~ tot 

UJ 

0 

::tl 

< t>:l 

~ 

::tl 

t>:l 

UJ 

t>:l 

> 

::tl 

@ 

-co 

0") 
. SHORT PAPERS IN THE GEOLOGFC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-119 

linite, but its l'(:"'frnetiYe indices (1.61 to 1.62) and the 

high content of iron that must be assigned to this mineral (table 331.1, depth 2:>0 feet) support its identification as a chlorite. This mineral is similar to some of 

the chamosites described by.Brindley (1951). 

Illite seems to be con fined to slightly altered granodiorite, where the amount of illite does not exceed the 

original percentage of biotite in the granodiorite. Illite may be pr~sent. elsewhere bnt obsc.ured by other 

clay minerals. 

DRILL-HOLE GS-2 . 

Drill-hole GS-2 is ·on the liigh Terrace of Steamboat 

Sprin~s in t.he not't'h west<:'rn pn l't of the thermal area · 

(),,100 feet no1th-nort·h"·est- of drill-hole GS-1. The 

I-Iigh Terrace has had little or no surface discharge 

since the Pleistocene, but thermal water flows in the 

system and escapes below the surface. Descriptions of 

t.he rocks found in drilling are given on figure 331.2 and 

in table 331.2. 

The assemblage of hydrothermal minerals in .hole 

GS-2 varies considerably with depth and differs from 

the assemblage in hole GS-1. Beginning a.t approximately 90 feet, silicates are repla,ced extensively by 

!(-feldspar. Quartz and !(-feldspar are the dominant 

hydrothermal minerals to a. depth of approximately 

280 feet, where clay minerals become abundant. The 

clays are dominant from 288 feet to the basal contact 

·of tuff breccia at 351 feet. From. 200 to 240 feet the 

only identified clay mineral is chlorite-vermiculite(?) 

with regular mixed layering: The X-ray pattern of 

the clay shows a basal reflection .at approximately 28 

A, and an integral series of 9 well-defined higher 

orders. Upon saturation with ethylene glycol the lattice expands to 31.5 A; heat treatment at 550° C for 

two hours results in a poorly defined X-ray peak at' 

approximately 23 A, and two higher orders at 12 and 

8 A. As defined by Lippmann (1956), this mineral 

is a corrensite; it was not found below 277 feet. 

At about 240 feet chlorite and a random mixedlayer illite-montmorillonite appear. The chlorite is an 

iron-rich variety, showing a low intensity X-ray peak 

at 14 A and a strong (002) reflection at 7 A. Chlorite 

is dominant near 300 feet but is not present at the 

contact with granodiorite. BE:llow the contact chlorite 

is abundant again, but as a replacement of biotite. 

TARLE 3:31.2.-Analyses of hydrothermally altered rocks of drill-hole GS-2 

!In percent; analyzed by rapid methods by L. Shapiro, H. F. Phillips, K. White, S. M. Berthold, and E. A. ~ygaard] 

Rocks in GS-2, and depth, in feet 

Chnlccdonlc Tuff-breccia, Tuff-breccia, Tuff-breccia, Tuff-breccia, Tuff-breccia, Tuff-breccia, Oranodio- Oranodio- Oranodiosinter, 28 125 single pebble, 202 239 297 317 rite, 355 rite, 367 rite, 375 

138 

--- -----

Constituent: 

SIO, _______________ • __ 98.6 75.0 62.5 84.0 79.0 70.2 74.8 75.2 71.2 72.2 

AhOa------·---------- . 58 II. 6 18.0 7. 8 10. 1 12.7 10.0 13.9 15.0 15.0 

FeO.----------------- . 16 } 2. 9 2. 2 1.1 . 96 3. 1 4. 2 1.6 1.6 { . 89 

l~e203 •--------------- <.10 .6 

MgO .•••••......•.... .00 . 15 . 28 .14 . 40 . 97 1.3 . 15 . 30 . 44 

Ca<Y' .•. --------------- . 06 1.5 1.1 . 18 . 44 1.3 . 34 . 82 1.7 1.3 

~1\20 ..•••••••• _______ . 22 . 91 1.5 . 20 .32 .28 . 39 1.5 2. 9 3. 2 

K,O •••• -------------- .09 6. 0 10.8 5. 8 8. 2 8. 3 3. 6 4.8 5. 1 4. 6 TIO,_. _______________ . 04 .54 . 58 . 22 .30 . 46 . 40 . 40 .. 86 . 32 

p,oa __________________ . 01 . 04 . 08 . 02 .05 .17 . 07 . 04 .13 . 10 

MnO •. --------------- .00 .oo . 01 .00 . 01 .06 . 02 . 01 .01 .01 

002·--------·----·--- <. 05 . 20 .10 <.05 . 25 . 77 <.05 <.05 . 30 <.05 

s .............. _______ .03 1.9 1.0 .68 .37 . 73 1.4 . 88 . 53 . 44 

H20+----------------} 

ri20-•• -------------- 1.1 2. I 2. 3 . 82 . 81 1.7 3. 8 2. 8 1.5 1.2 

Total as reported ... 100.9 102.8 100.5 101.0 101.2 100.7 100.3 102. I 101. 1 100.3 Less 0 for S __________ -------------- 1.0 .5 .3 .2 . 4 .7 .4 .3 .2 TotaJ. ______________ 100.9 101.8 100.0 100.7 101.0 100.3 99.6 101.7 100.8 100.1 

Specific gravity (powder). 2. flO 2. 64 2. 65 2. fl4 2. 62 2. 61 2. 68 2. 59 2. 64 2. 66 

Specific gravity (lump) ... 2. 45 2. 44 2. 48 2. 38 2. 39 2. 47 2. 41 2. 47 2. 47 2. 51 

Prominent hydrothermal Chalcedony K-feldspar, K·feldspar, K-fcldspar, K-feldspar, K-feldspar, Illite-mont- Illite-mont- Illite-mont- Illite-montmlnernls. (stlbnite). quartz, py- qunrtz, quartz (py- quartz, cor- chlorite, morillonite, morillonite, morillonlte, morillonite, 

rite, (clays, (clays, py- rite). rensite, (py- quartz, il- chlorite, quartz, (py- chlorite, chlorite, (calcalcite). rite, calcite). rite, calcite). lite, mont- quartz, K- rite). quartz, cite, quartz, 

morlllonite, feldspar, (calcite, py- pyrite). 

(calcite, py- (pyrite). rite). 

rite, apatlte(?)). 

1 Or total Fe as Fe203. 
1-

UJ 

UJ 

LL. 

z 

TEMPERATURE, "C 

20 40 60 80 100 120 140 160 

0 

CONDENSED 

180 LOG 0 

'

Sinter, opaline and chalcedonic 

~ 

APPROXIMATE PROPORTIONS OF 

PRINCIPAL MINERALS 20 40 60 80 

Opal. chalcedony, and clastic minerals 

(largely unaltered in upper part, increasing replacement downward by Kfeldspar) 

Alluvium, 

100 minor 

sinter 

UNCONFORMITY 125 '\ i Q)~ \ I 

138 ~ ~ ~ I 

-g·~ / / ~-g / / 

0:. !':- I I I I I I 

Veins / / I I I I I I I I 

150 

>. 

c 

0 

"0 

Q) 

.!d 

«< 

.c 

u 

I I "0 

100 

-: 200 202 c( c 

"' \ Hydrothermal ', 

\ K-feldspar · ', 

Veins ' ', 

\ ' 229 ~ ', 

·~ 239 (\ \~ 

~ 241 Q) \ , .... , \ 

.0 :!: \ \ ', \ 

::: ~ \ \ ', \ 

Veins .;l e \ \ ',, \ . !::! 0 \ \ .... , \ 0 ·~ 277 (..) .> ''i . .......... y /' "C ," ' .............. I ~ c , I ... I Thermistor temperature measurements in l <C 288 ~ Q) ~ ,:JJ 1 water column 5 days after hole completed 297 ! ·~ ~ q;""'"' ~ 

, 2. ' , / ::>.' , 

,' 0 ~ ',, / 

317 ; .s Qj ' r/ I g >. \ I I E ~ I I 

Veins / a, -g \ f 

~ ·~ \ I 

346 - ~4 35o r 600,, ,, e Repeat measurements ITY f ', ', after interval with no 367 &. '~ ',"' 

drilling Grano- .. .., :ll .. , diorite 375 '9 Plagioclase 'l ~ i : (oligoclase) : g 1 

I 1 :S I 

400L_ ______ L_ ______ i_ ______ J_ ______ J_ ______ _L ______ _L __ ~~_L ______ _L ______ ~~----~--------~--~~--~ I : o ~ 

300 

:I: 

1-

a.. 

UJ 

0 

250 

t 

"' ::J

0 

FIGURE 331.2.-Data from drill-hole GS-2, High Terrace, Steamboat Springs, Nev. Straight lines arbitrarily drawn between points of observation . 

... 

tj 

I 

jooooO 

~ 

0 

i:"j 

0 

~ 

0 

0 

I-< 

0 

> 

~ 

IJ1 

q 

~ 

< 

tr:1 

~ 

~ 

M 

IJ1 

M 

> 

~ 

0 

~ 

..... 

~ 

C) 
'\ 

I 

SHORT PAPERS IN THE GEOLOGJ.lC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-121 

The illite-montmorillonite mixed-layer clay becomes 

incrensingly nbnncln.nt and K-feldspar correspondingly 

less abundant downward; the illite-montmorillonite 

mixed-layer clay reaches its maximum concentration 

near the contact with granodiorite. The proportions 

of the mixed-layer components are consistent throughout roeks penetrated; the expandable montmorillonite 

ln.yers make up about 25 percent of the total clay as 

indicated by the ( 001) I ( 001) peak of the glycolated 

sample ('Veaver, 1956, p. 206). 

Small amounts of probable illite were observed 

microscopicn.lly in several samples below 250 feet in 

hole GS-2 but the occurrences could not be confirmed 

by X-ray ann.lysis, presumably because of dominance 

of other clay minerals. 

CONCLUSIONS 

The hydrothermal mineral assemblages are virtually 

independent of the original rock type. The extent of 

alteration, however, is greatly dependent upon the pro- . 

portion of minerals susceptible to attack. 

The Low Terrace is sti11 undet:going active alteration by slightly acid, carbonated waters, as indicated 

by pli and by high concentrations of bicarbonate and 

calcium in the water (table 331.3). l(aolinite is the 

most stable mineral; other silicates are probably 

metastable or are intermediate products. 

The liigh Terrace has probably been inactive at the 

surface since Pleistocene. The most stable minerals 

are !(-feldspar near the surface, and probably illite 

a.t depth. These minerals are in other stability fields 

t·han kaolinite in the system J(20-Al20a-Si02-H20 

(liemley, 1959, p. 246). 'Vaters from both drill holes 

nre very similn,r in potassium content, temperatures, 

and pl-I. The piT of both is 6.0 ± if non erupted, and 

8.0 or more if erupted because of loss of C02 ("Vhite, 

Sandberg, and Brannock, 1953, p. 496-498). 

The mineralogy of the High Terrace is best explained 

by higher wa.ter temperatures in the past. Higher temperatures could have increased the extent of boiling in 

the upper pa.rt of the conduit system of the springs, 

thereby increasing pH by perhaps a. unit or more bec.ause of the volatilization of free C02, and also increasing potassium slightly because of loss of water as steam. 

'fhese changes favor deposition of !(-feldspar over mica 

(illite), a.nd presumably more than offset the effect of 

decrease in temperature upwards, which should favor 

deposition of mica (1-Iemley, 1959). A higher concentration of potassium than at present in the deep water 

also may be required to span the differences between 

the stability fields of kaolinite and !(-feldspar. 

604493 0-61--9 

TARLE ;{:31.:3.-A nalyses of thermal waters of Steamboat Springs. 

Nevada 

[Analysts W. W. Brannock and H. Kramer] 

Spring 27, 

Main 

Terrace 

Physical state __ ---------------_-----_ Discharging 

Temperature at collection point, deDrill-hole 

OS-1, Low Terrace 

Leaked from 

valve. 

grees o_ ---------------------------- 89. 2 47 

Bottom-hole temperature, degrees 0 __ ------------ ~ 160 

pH----------------------------------- 7. 9 6.1 

Analysis, in part.s per million: 

Si02------------------------------ 0a _______________________________ _ 

l\1g ______________________________ _ 

293 

5. 0 

.8 

X a ___ ---------------------------- 653 

K-------------------------------- 71 

LL------------------------------- 7.6 

H003- ________ ------- _ ---- ____ --- 305 

003------------------------------ nil 

804------------------------------- 100 

OL_ --------------- __ ------------- 865 

F--------------------------------- 1.8 

B--------------------------------- 49 

l-I2S--- --------------------------- 4. 7 

Total as reported_______________ 2, 356 

Ratios: 

Oa(~a---------------------------- 0. 008 K/Sa_____________________________ . 11 

Li(Na ___ ------------------------- . 012 

H003/0l•_ -·--------------------- . 35 804/0L_________________________ .12 

F/OL---------------------------- . 002 

B/OL--.-------------------------- . 057 

18 

nil 

627 

60 

5.8 

404 

nil 

112 

817 

2. 0 

2 37 

11 

3 2,094 

0.029 

.09() 

.0093 

. 50 

. 14 

.002 

. 045 (?) . 

1 Total combined carbonate calculated as equivalent H003. 

2 May be low. 

3 8!02 not reported. 

Drill-hole 

OS-2, High Terrace 

Erupted · 

>95 

~160 

8.8 

4. 4 

nil 

655 

73 

5. 7 

77 

94 

132 

871 

1.0 

2 36 

1.1 

3 1,950 

0.007 

.11 

. 0088 

. 31 

. 15 

. 001 

. 041 (?) 

Remley (Art. 408) has shown tha.t the stability field 

of mica is wide in the K20-Al203 -Si02-H20 system, but 

is greatly narrowed in the N a20-A.1203 -Si02-H20 system. His work suggests that in natural waters containing both K and N a, the differences between replacement 

o£ plagioclase by K-feldspa.r or by ·kaolinite is determined by as little as 1;2 unit of pH, 50° C in temperature, 

or a. variation in concentration of potassium of % an 

order of magnitude. 

REFERENCES 

Becker, G. F., 1888, Geology of the quicksilver deposits of the 

Pacific slope: U.S. Geol. Survey Mon. 13, 4:86 p. 

Brannock, W. W., Fix, P. F., Gianella, V. P., and White, D. E., 

1948, Preliminary geochemical results a!t Steamboat Springs, 

Nevad'a: Am. Geophys. Union Trans., v. 29,. p. 211-226. 

Brindley, G. W., 1951, The crystal structure of some chamosite 

minerals: Mineralog. Mag., v. 29, p. 502-fi25. 

Hemley, J. J., 1959, Some mineralogical equilibria in the system 

K20-AhOa-Si02-H20: Am. Jour. Sci., n.s., v. 257, p. 241-270. 
D-122 GEOLOGICAL SURVEY RESEARCH 1 9 61 

LeConte, Joseph, 1883, On mineral vein formation now in progress at Steamboat Springs compared with same a!t Sulphur 

Bank: Am. Jour. Sci., ser. 3, v. 25, p. 424-428. 

Lippmann, F., 1956, Clay minerals from the ROt member of the 

Triassic near GBttingen, Germany: Jour. Sed. Petrology, 

v. 26, p. 125-139. 

Weaver, C. E., 1956, The distribution and identification of mixedlayer clays in sedimentary rocks: Am. Mineralogist, v. 41, 

p. 202-221. 

White, D. E., 1955, Thermal springs and epithermal ore deposits : 

Econ. Geology, 50th Anniv. Volume, p. 99-154. 

-- 1957, Thermal waters of volcanic origin : Geol. Soc. 

America Bull., v. 68, p. 1637-1658. 

White, D. E., Sandberg, C. H., ·and Brannock, W. W., 1953, Ge<r 

chemical and geophysical approaches to the problems of 

utilization of hot spring water and heat: Pacific Sci. Cong., 

7th, New Zealand, 1949, Proc., v. 2, p. 490-499, Wellington. 

332. CORRELATION OF THE DEPOSITS OF LAKES LAHONTAN AND BONNEVILLE AND THE GLACIAL 

SEQUENCES OF THE SIERRA NEVADA AND WASATCH MOUNTAINS, CALIFORNIA, NEVADA, AND UTAH 

By R. B. MoRRISON, Denver, Colo. 

l\1odern stratigraphic studies of the deposits of Lakes 

Lahontan and Bonneville and of the Quaternary glacial 

deposits of the Sierra Nevada and W asat.ch Mountains 

permit improved correlation of these sequences. Direct 

correlation is possible at only one locality : below the 

mouths of Little Cottonwood and Bells Canyons, south 

of Salt Lake City, Utah. Here, drift of one of the late 

Quaternary glaciations of the Wasatch Mountains 

intertongues and intergrades with part of the Lake 

Bonneville sequence (Art. 333 ; Richmond, Art. 334). 

Correlations can be made indirectly, however, between 

the remainder of the Lake Bonneville and Wasatch 

l\1ountain glacial sequences, and between these and the 

Lake Lahontan and Sierra Nevada sequences, by the 

use of new concepts of soil stratigraphy (Ricl;tmond, 

1950; Richmond, Morrison, and Bissell, 1952). 

The late Quaternary successions in all four areas 

have similar soil sequences, in terms.of relative age and 

relative development of the soils. The physical record 

in each area indicates that the soils formed during distinct, widely separated intervals, in response to relatively infrequent combinations of climatic factors that 

induced erosional stability and a more rapid rate of 

chemical weathering than normal. The most strongly 

developed soils formed during the main intervals of 

lake desiccation or of deglaciation; weaker soils formed 

during the shorter recession intervals; soil profile development at other times was inappreciable. The soilforming intervals were periodically repeated parts of 

whole climatic cycles-mainly fluctuations in temperature and precipitation-that are manifest in the 

Quaternary sequences of each area. The climatic 

cycles, and the depositional and soil-forming cycles 

induced by them, probably were essentially synchronous 

over the entire Wasatch Mountain to Sierra Nevada 

region because the whole region probably acted as a 

climatic unit during the Quaternary as it does now. 

Thus, soils of similar relative age and development in 

the four areas are assumed to have forn.1ed contemporaneously-in other words, they are assumed to be 

nearly time-parallel throughout this region. Because 

they formed during generally shorter intervals than the 

inter-soil sediments, they are considered to be more 

precise time-stratigraphic markers. The stronger soils 

are readily recognizable in the successions of each area 

and are the most reliable and useful markers; they 

provide the basic framework for correlation. The 

sediments and weaker soils intermediate in age between 

the main soils are correlated by matching those units 

that record depositional cycles, or parts of cycles, of 

similar relative age and similar climatic genesi~that 

is, units recording early lake cycles with each other and 

with units recording early glacial cycles; likewise, lakerecessional units are correlated with glacial-recessional 

units. 

Figure 332.1 diagrams the means of correlation. 

(The stratigraphic units and interpretations of lake 

and glacial history listed below and in figure 332.1 are 

those given in the following papers in this review, or 

other references : for the Lake Lahontan area, Art. 329 ; 

for the Sierra Nevada, Blackwelder, 1931; Matthes, 

1942, 1945; Putnam, 1950; and for the Lake Bonneville 

and Wasatch Mountains areas, Morrison, Art. 333, and 

Richmond, Art. 334.) First, soils of similar relative 

development are correlated, starting with the three 

youngest most strongly developed soils in each 

sequence; then, between main soils, the deposits that 

record depositional cycles of similar age and magnitude 

are correlated, as are any weakly developed soils. 

By this method, the. pre-Lak~ Lahontan soil of the 
.... 

'· 

' 

Time 

.... 

c 

Q) 

~ 0:: 

Q) 

c 

Q) 

"ij 

~ 

a: 

! 

j 

SHORT PAPERS IN THE GEOLOGJIC AND HYDROLOGIC SCIENCES, ARTICLES 293-4135 D-123 

Glacial till Interglacial de· Subaerial deposits, soils, and lacustrine deposits and outwash posits, soils, and disconformities indicating and inferred lake disconformities lake recessions fluctuations 

p-:::.:: .. -_-:.::::::::~ ,------~ ,------4-------------, 

ALTITUDE OF LAKE LEVEL, IN FEET 

~ ~ ~ ~ ~ ~ • .., 

c: 

0 

:0: 

'ij "' c: Qo "' 0 

~C' 

"' «~ro 

110 e·;;: 0 ... Q) 

j:: oro 

Ql -.o 

1/l::::l 

-s Q)l/) 

.... 

0 ~~ ...JC: 

.c c:'Cii Ill .~ E "' l "0 ...... 

E :I Q. 0 

'0 :J c: 0 

"' '-

bO j:: >. \ ~ I (ij 

Wyemaha formation I > I 

Prominent disconformity (subaerial and I c 

shallow-lake) I :1 

I c 

' 0 

.c I 

Jl "' ...J 

I 

l 

I 

I 

I c: 

0 I :0: Q) I "' tlO I ·u «< 

"' «< Qj' I 

Qo .!::! c: I Ql Q) :s I 0 UJ Ill I .c 0 ::::l I "' u 1- E «< I Ql ::::l 

;::::.. 

-s ·;;; Very weak soil··· • j c: 

0 .... -= :;::; 0 0 «J, 

.c 

Ill u ·e 

"' "0 ·-2 l c: 

«< «< :I 

E 0 .!::! 

Q). 

'0 ::::l UJ c: ·;;; 

"' -= ~ < 

' ':1 "I 

rmMili,lilllll'lil,mi,ltmrr,mmli I 

' I 

Paiute formation I 

Marked disconformity I 

(subaerial) I 

I 

I 

I 

Sierra Nevada 

Lake Lahontan, 

Carson Desert, Nevada 

Subaerial deposits, soils, and 

disconformities indicating 

lake recessions 

lacustrine deposits 

and inferred lake 

fluctuations 

c: 

0 

:0: 

·u "' 

Qo "' 

Ql 

iii 

'0 

Ql 

c: 

i:i: 

Ql 

-s 

0 

.c 

Ill 

i 

:I 

0 

'0 

c: 

"' 

c: 

0 

~ ·u 

Qo "' 

Ql 

~ 

"' .J 

"5 

ID 

Ql 

-s 

0 

.c 

Ill 

~ "' 

:I 

0 

'0 

c: 

"' 

j:: 

,--------___,_, ,..---A----- -----, 

ALTITUDE OF l.AKE LEVEL, IN FEET 

Alluvium and eolian d•~posits 

~;;,-----·----------­

' /oo 

Prominent disconf•xmity; 

local alluvium 

........... ................ !!_onnecii~e shoreline 

t ........... oo o t: U tt.._o o 

\ t .!.--J-;ooo 

----- 0 

......................... ~--... 0 

t---q_o,, 

t t t '( 

t t L t lc t t tt 

t t --· o· ,__..-L...,.,.----0 00 0 0 

--

L 

Fan gravel and colluvium of 

pre-Lake Bonneville age 

1 

·c: -::::l 

.... 

Q) 

~ 

0 

...J 

"' Ql 

:v 

·= c: 

0 

:0: 

"' >

Ql 

Gi 

... 

Ill 

Ql 

Q. 

:J 

e 

bO 

~ 

·:;: 

Q) 

c 

c 

0 

m 

Q) 

.:.:. 

"' ...J 

Lake Bonneville (Lower Jordan Valley) and 

Wasatch Moun1tains, Utah 

l•'wum·~ 332.1.-Correlation of the late Quaternary sequences of the Sierra Nevada, Lake Lahontan (Art. 329), Lake 

Bollll('\"ille nnd \Vn:-;utdl 1\iountaiu:-; ( ~Iorri:-;ou, Art. :333, Hll{l Riehmoud . .Art. :~:{-!) a rpa:-;, :-;howiug the ag'P rt:>lntiou:-; of 

deposit.-; nnd :-;oils, nnd inferred lake and glacial fluctuations. U, upper part; l\1, middle part; and L, lower part of 

u lncu~o;trine or glacinl unit; lc, lake cycle; t, till; o, outwa:o;h; number~ refer to lake cydes. 
D-124 GEOLOGICAL SURVEY RESEARCH 19 61 

Carson Desert, Nev., is correlated with the pre-Lake 

Bonneville soil (pre-Wisconsin soil of Hunt and Sokoloff, 1950) in the Lake Bonneville and Wasatch Mountain areas and with the soil of pre-Tahoe age in the 

Sierra Nevada; the mid-Lake Lahontan soil is correlated with the mid-Lake Bonneville soil, and with soils 

of inter-Bull Lake-Pinedale age and inter-Tahoe-Tioga 

age in the Wasatch Mountains and Sierra Nevada, respectively. The post-Lake Lahontan soil is c9rrelated 

with soils of post-Lake Bonneville, post-Pinedale, and 

post-Tioga age. 

The deposits intermediate in age behveen these main 

soils are correlated as follows: the Eetza formation of 

the Carson Desert area is correlated with the lower 

unit of the Lake Bonneville group (which includes 

the AI pine, Bonneville, and most of the Provo formations of Hunt (1953) ), and with drift of the Bull Lake 

and Tahoe glaciations in the Wasatch !\1ountains and 

Sierra Nevada, respectively. The Wyemaha formation 

is correlated with subaerial deposits intercalated between the lower and upper units of the Lake Bonneville 

group and with disconformities of inter-Bull LakePinedale age in the Wasatch Mountains and interTahoe-Tioga age in the Sierra Nevada. The Sehoo and 

Indian Lakes formations are correlated with the upper 

unit of the Lake Bonneville group, and with drift of 

the Pinedale and Tioga glaciations jn the Wasatch 

Mountains and Sierra Nevada. The Turupah formation is correlated with deposits of Antevs' "altithermal 

age'' (1948, 1952, 1955) (2,000 to 5,500 B.C.) in the 

Great Bas,in. The Fallon formation is correlated with 

deposits of Antevs' "medithermal age" in the Great 

Basin, and with drift of Matthes' "little ice age" (1942, 

1945) in the SierraN evada. 

These correlations, if valid, lead to several genera] 

deductions about regional Quaternary events: 

1. The fluctuations of Lakes Lahontan and Bonneville 

were similar and synchronous. 

2. The fluctuations of both lakes paralleled those of the 

glaciers in the Sierra Nevada and Wasatch Mountains; i.e., when the lakes were high the glaciers were 

extensive. The more complete record in the basins 

gives indirect evidence of glacial oscillations not yet 

recognized in the mountains. 

3. Lake Lahontan, and probably Lake Bonneville, dried 

up entirely during a long period between the two 

major deep-lake intervals, .and the Sierra Nevada 

and Wasatch Mountains were probably tlien completely deglaciated. 

REFERENCES 

Antevs, E. V., 1948, Climatic changes and pre-white man, in 

The Great Basin, with emphasis on glacial and post-glacial 

times: Utah Univ. Bull., v. 38, no. 20, p. 168-191. 

-- 1952, Cenozoic climates of the Great Basin: Geol. 

Rundschau, v. 40, no. 1, p. 94--108 (in English). 

-- 1955, Geologic-climatic dating in the west [U.S.]: Am. 

Antiquity, v. 20, no. 4, pt.1, p. 317-335. 

Blackwelder, Eliot, 1931, Pleistocene glaciation in the Sierra 

Nevada and Basin Ranges: Geol. Soc. America Bull., v. 42, 

no.4, p. 865-922. · 

Hunt, C. B., 1953, General geology, in Hunt, C. B., Varnes, 

H. D., and Thomas, H. E., Lake Bonneville-geology of 

northern Utah Valley, Utah: U.S. Geol. Survey Prof. Paper 

257-A, p. 11-45. 

Hunt, C. B., and Sokoloff, V. P., 1950, Pre-Wisconsin soil in the 

Rocky Mountain region, a progress report: U.S. Geol. 

Survey Prof. Paper 221-G, p. 109-123. 

Matthes, F. E., 1942, Glaciers, in Meinzer, 0. E., ed., Physics of 

the earth, Hydrology, pt. 9: New York, McGraw-Hill Book 

Co., p. 149-219. 

-- 1945, Post-Pleistocene deglaciation and reglaciation 

[abs.]: Geol. Soc. America Bull., v. 56, no. 12, pt. 2, p. 1181. 

Putnam, W. C., 1950, Moraine and shoreline relationships at 

Mono Lake, Cali~ornia: Geol. Soc. America Bull., v. 61, 

no. 2, p. 115-122. 

Richmond, G. M., 1950, Interstadial soils as possible stratigraphic horizons in Wisconsin chronology [abs.]: Geol. 

Soc. America Bull., v. 61, no. 12, pt. 2, p. 1497. 

Richmond, G. M., Morrison, R. B., and Bissell, H. J., 1952, 

Correlation of the late Quaternary deposits of the La Sal 

Mountains, Utah, and of Lakes Bonneville and Lahontan 

by means of interstadial soils [abs.]: Geol. Soc. America 

Bull., v. 63, no. 12, pt. 2,.p.1369. 

··' 
~· 

SHORT PAPERS IN THE GEOLOGJIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-125 

333. . NEW EVIDENCE ON THE HISTORY OF LAKE BONNEVILLE FROM AN AREA SOUTH OF SALT LAKE 

CITY, UTAH 

By R. B. MonmsoN, Denver, Colo. 

Recent mapping of the Quaternary deposits in t,he 

eastern half of Lower Jordan Valley, south of Salt 

Lake City, has produced additional information on 

oscillations of Lake Bonneville. Fan gravel and colluvium antedating Lake Bonneville are loca..lly exposed, 

mainly in faulted remnants along the edge of the 

"Vnsat:ch l\{ountains. These deposits bear a very mature 

soil, the "pre-"Visconsin pa.leosol" and "ancient soils" of 

IIunt and Sokoloff (1D50, p. 114-115) and IIunt (1953, 

p. 43-44), which is directly overlain by the earliest sediments of Lake Bonneville. This soil is 5 feet or more 

thick where well preserved, with a strongly textured 

brown B horizon and, n mile or more 'vest of the mountain front, a dense Ccn ( cn1iche) horizon. 

In this area the deposits of Lake Bonneville (Lake 

Bonneville group) are tnost feasibly divided into two 

main units (fig. 333.1). These units are separated by 

u. mature soil, local alluvium, and a disconformity that 

together record subaerial exposure at least as low as 

-!,250'feet altitude-only 50 feet· above the ,June 1!)51 

level of Great Salt Lake. The lower unit comprises 

two tongues of lacustrine sediments separated by another disconformity and by local alluvium recording 

· subaerial exposure at least as low as 4,270 fe~t altitude. 

The disconformity and alluvium are discontinuous, 

however, and the two tongues can be differentiated only 

locally. l''he lower tongue, which is approximately 

equivalent to the Alpine formation of IIunt ( 1953), 

reaches a maximum altitude of about 5,100 feet, and 

is inferred to record the first. deep-lake cycle of Lake 

Bonneville. The upper tongue, 'vhich includes Hunt's 

Bonneville and Provo formations, extends as high as 

the Bonneville shoreline (about 5,135 feet altitude west 

of the main "Vasatch fault zone) and is inferred to 

record the second, and highest, lake cycle. During the 

reces.sion from this maximum, a long stillstand at an 

altitude of about 4,800 feet is recorded in the welldeveloped Provo shoreline. 

The mid-Lake Bonneville soil, intermediate in age 

bet·ween the lower and upper units of the Lake Bonneville group, is thinner (typically 3 to 4 feet thick) than 

the pre-Lake Bonneville soil; its B horizon is distinctly 

less clayey and is generally lighter brown; and the 

Ccn horizon, where present· in the "·estern part of the 

area, has less calcium carbonate. 

The upper unit of the Lake Bonneville group comprises three tongues of lacustrine sediments, each locally 

separated by disconformities that record subaerial erosion. The ]ower tongue reaches a maximum altitude of 

about 4,770 feet, not quite as high as the Provo shoreline. The middle and upper tongues reach altitudes as 

high as 4,470 and 4,410 feet, respectively, but these 

maxima are only faintly marked by shore features and 

shore deposits. The disconformities between each 

tongue have been identified as low as l1;450 ancl4,3GO feet 

altitude, respectively, and probably extend ]ower. The 

three tongues are inferred to record the last 3 cycles of 

Lake Bonneville. This unit bears a submature soil that 

typically is 2 to 21j2 feet thick and is somewhat less 

strongly developed and lighter colored than the midLake Bonneville soil. Post-Lake Bonneville deposit's 

include alluvium and local colluvium, eolian sand, and 

loess. The post-Lake BonneviJle soil is locally intercnlated between the ]ower and upper parts of the eolian 

sand. 

Thus, the stratigraphic record shows that Lake Bonneville had 5 lake cycles, during which, from oldest to 

youngest, the lake level rose to about 5,100, 5,135, 4,770, 

4,470, and 4,410 feet altitude. During the intervening 

recessions, the lake level dropped at least as low as 830, 

885, 320, and 110 feet, respectively, below the preceding 

maximum. This is in accord with tlw conclusions of 

Gilbert (1890), Antevs (1D45, 1D48), Ives (1951), Hunt 

(1953), and Eardley, Gvoscletsky, and l\{arse1l (1957) 

on the age relations and maximum height of the first 

two lake cycles. It is in contrast with each of these 

interpretations, however, in that the longest and probably most complete lake desiceation appears to have 

been between Jake cycles 2 and 3 (not between 1 and 2). 

The long stillstand at the Provo level was during the 

recession of lake cycle 2, as Gilbert and IIunt inferred, 

and not mainly during lake cycle 3, as Antevs ( 1945, 

1948, 1952, 1955), Ives (1951), apd Eardley, Gvosdetsky, and M:arsell (1957) concluded. The 3rd lake 

maximum is equivalent to the "Provo 2" maximum of 

.Tones and MarseJl (1D55), Bissell (1952), Antevs 

(1952, 1955), and Eardley, Gvosdetsky, and l\farsell 

(1957). The 4th lake maximum was at the average 

altitude of the Stansbury shoreline of Gilbert (1890), 

of the "Lake Stansbury II" stillstand of Antevs ( 1945, 

1948, 1952, 1955), and of the "Stansbury stage" of I ves 

( 1951), and of Eardley, Gvosdetsky, and l\{arsell 

( 1957). There is neither stratigraphic nor geomorphic 

confirmation of a comparatively long stand at and near 
D-126 GEOLOGICAL SURVEY RESEARCH 1 9 6 1 

Lacustrine deposits and inferred 

Subaerial deposits, soils, and disconformities lake fluctuations 

indicating lake recessions r-~---~ 

~------, 

Time 

Altitude of lake level, in feet -

8 8 8 8 8 ° ~~ N 0 00 cD -.::r ~ ~....J-"' U') Ll') ~ 'll:t q- ...... 

~; Q) I 

a::, 

Alluvium, eolian sand, and loess 

c<V 

«<(I) 

-e~ ol!! 

"'~ ~ 

Q) 

c: 

Q) 

(.) 

~ ·a; 

a: 

~ 10 

....J 

I 

i 

Post-lake Bonneville soillsubmature) 1----

c 

,g Eolian sand, loess 

1iO 

-~ ~ ~-'U1%o 

t/ Alluvium ;; -., ,s 

1 

l t' ~o 0 Disconformity ~ ""'t 0::: t Mt 0 >4360 ft alt o~M' .~ ., t t,z0 o '<T c l c: .r:. t ~-oo Alluvium '<T • ,~)) =: 

2 0 t 

~,;J~ ~ >4450 ft alt_ . < : g .r:. t 0 - . . 

~ t lt t o 0 AIIuvium ,.... ~·L"tld),: 

-=c

it t t t "( :· ' . - t 0 0 ..,. O'.fe!'' '' 

"a ," 0 ~~ . ~ ; ,.,"' (9/ ~ 

1111111111111111111111111111 

Middle lake Bonneville soil (mature) 

Oisconformity and 

>4250 ft alt 

Alluvium 

{ 

- ...... ...._ Bonneville ~ ............ ...._ shoreh 

~ t t 

:;: t t 

1iO t t_.. 

Q) ---- 5 ---

um 

·1111111111111111111111111111' 

Pre-lake Bonneville soil (very mature) 

Fan gravel and colluvium of 

pre-Lake Bonneville .age 

FIGURE 333.1.-Stratigraphic record of fluctuations of Lake 

Bonneville. U, upper part; M, middle part; and L, lower 

part of a lacustrine or gladal uuit; lc, lake cycle; >, disconformity observed as low as the altitude given; t, till; o, 

outwa!'lh; numbers refer to lake e:r<:le. 

the Bonneville shoreline as recently as 25,000 to 15,000 

years ago nor of another even more recent rise above 

the Provo level (between 12,000 and 11,000 years ago), 

as Broecker and Orr ( 1958) inferred from radiocarbon 

dating. 

Since Gilberfs (1890) study it has been known that 

below the mouths of Little Cottonwood and Bells Canyons bulky moraines extend somewhat below the level 

of the Bonneville shoreline, permitting reasonably 

direct correlation of parts of the glacial and lacustrine 

sequences, although various geologists have differed as 

to the conelations. The glacial geology of these canyons "·as recently mapped by G. l\1. Richmond, and he 

arid I jointly studied the interrelations of the glacial 

and lacustrine deposits. Below the mouth of each canyon is a set of end moraines, representing two separate 

advances of glaciers from these canyons, which we correlate with the early and late stades 1 of the Bull Lake 

glaciation of the Rocky Mountains. Around the outer 

margins of the moraines, till and outwash of the early 

stade interfinger with the lower lacustrine tongue of 

the lower unit of the Lake Bonneville group, and drift 

of the late stade interfingers with the upper tongue of 

this unit. The higher shorelines of the first lake cycle 

notch the end moraines of the early stade, and the Bonneville shoreline is carTed into the end moraines of the 

late stade, contrary to the conclusions of Gilbert (1890) 

and Blackwelder ( 1931). The relations indicate that 

the two lake maxima were essentially contemporaneous 

with or perhaps slightly later than the corresponding 

glacial maxima. 

El)d moraines of post-Hull Lake age are far above 

the Bonneville shoreline in both canyons, and the intervening remnants of outwash gravel!? and stream terraces 

are too discontinuous to permit reliable direct correlation behYeen the younger glacial and lacustrine sequences. These sequences can be indirectly correlated, 

however, on the basis of relative stratigraphic position 

· of soils of similar maturity in each sequence. The drift 

of the Bull Lake glaciation bears a mature soil, comparable in development to the soil of middle" Lake Bonneville age. A submature soil, similar to the post-Lake 

Bonneville soil, is developed on three sets of end moraines in the middle and upper parts of the canyons 

that Richmond (Art. 334) correlates with the early, 

middle, and late stades, respectively, of the Pinedale 

glaciation. Consequently, the upper unit of the Lake 

Bonneville group is correlated with the drift of the 

Pinedale glaciation. The lower, middle, and upper 

tongues of the upper unit are matched by (and prob1 A stade is defined as a climatic episode withiu a glaciation during 

which a secondary advance of glaciers may be lnferred1 (American Commission on Stratigraphic Nomenclature, 1961). 
I 

,I 

SHORT PAPERS IN THE GEOLOGJIC AND HYDROLOGIC SCIENCES, ARTICLES 2 9 3-4 3 5 D-127 

u.bly correlate with) the early, middle, and late stades 

o:f the Pinedale glaciation. 

REFERENCES 

American Commission on Stratigraphic Nomenclature, 1961, 

Code of strntigrnpbic nomenclature: Am. Assoc. Petroleum 

Geologists Bull., v. 45, no. 5, p. 645-665. 

Antevs, E. V., 1945, Correlation of 'Visconsin glacial maxima, 

·in, Problems in geology and geophysics (Daly volume 

243-A) :Am .• Tour. Set., p.1-39. 

--1048, Climatic changes and pre-white man, in The Great 

Basin, with emphasis on glacial and postglacial times: 

Utnh Uuiv. Bull., v. 38, no. 20, p. 168-191. 

--1952, Cenozoic climates of the Great Basin: Geologische 

Uundschnu, ''· 40, no. 1, p. !)4-108 [in English]. 

--1Hri5, Geologk-climntic dating in the west [U.S.] : Am. 

.Antiquity, v. 20, no. 4, p. 1. 

Bissell, H .. J., 1952, Strntigrnphy of r ... ake Bonneville and assoeiat:ed Qnnternm·y detwsits in Utah Valley, Utah [abs.] : 

Geol. Soc. America Bull., v. 63, no. 12, pt. 2, p, 1358. 

Blnckwelder, Eliot, 1931, Pleistocene glaciation in the Sierra 

Nevnda und .Bnsin Ranges: Geol. Soc. America Bull., v. 42, 

no. 4, p. 86fi-922. 

Broecker, ,V. S., and Orr, P. C., 1958, Radiocarbon chronology 

. of Lake Lahontan and Lake Bonneville: Geol. Soc. America 

Bull., v. 69, no. 8, p. 1009-1032. 

Eardley, A. J., Gvosdetsky, Vasyl, and Marsell, R. E., 1957, 

Hydrology of Lake Bonneville and sediments and soils of 

its basin [Utah]: Geol. Soc. America Bull., Y. 68, no. 9, p. 

1141-1202. 

Gilbert, G. K., 1890, Lake Bonneville: U.S. Geol. Survey Mon. 1, 

438 p. 

Hunt, C. B., 1953, General geology, in Hunt, C. B., Varnes, H. D., 

and Thomas, H. E., Lake Bonneville-geology of northern 

Utah Valley, Utah: U.S. Geol. Survey. Prof. Paper 257-A, 

p. 11-45. 

Hunt, C. B. and Sokoloff, V. P., 1950, Pre-Wisconsin soil in the 

Rocky Mountain region, a progress report : U.S. Geol. 

Survey Prof. Paper 221-G, p. 109-123. 

Ives, R. L., 1951, Pleistocene valley sedhnents of' the Dugway 

area, Utah: Geol. Soc. America Bull., v. 62, no. 7, p. 781-

797. 

Jones, D. J., and Marsell, R. E., 1955, Pleistocene sediments of 

lower Jordan Valley, Utah, in Tertiary and Quaternary 

geology of eastern Bonneville Basin: Utah Geol. So(•. Guidebook No. 10, p. ~5-112. 

334. NEW EVIDENCE OF THE AGE OF LAKE BONNEVILLE FROM THE MORAINES IN LITTLE COTTONWOOD 

CANYON, UTAH 

By G. M. RICHl\IOND, ,Denver, Colo. i 

I 

The glacial deposits of Little Cottonwood Canyon J.n 

t'lte "Tnsntch l\1ountains, Utah, represent three glaciations. Deposits of the oldest are probably of middle 

Pleistocene age and have been uplifted about 2,500 feet 

by normal faulting at the western margin of the mountains. 

Deposits of the next younger glaciation, correlated 

with deposits of the Bull Lake glaciation of Wyoming, 

comprise two sets of end moraines at the mouth of the 

canyon at altitudes of 4,980 and 5,090 feet, respectively. 

Till and outwash of the outer moraine interfinger with 

and nre overhtpped by deposits of the first rise of the 

lake-the Alpine formation of I-Iunt, Varnes, and 

Thomas (1953)-and till and outwash of the. inner 

moraine interfinger with and are overlapped by deposits of the second rise of the lake-the Bonneville 

formation (I-Iunt, Varnes, and Thomas, 1953)-or that 

which attained the Bonneville shoreline. 

The basin ward extent of a. disconformity which separates the Alpine and Bonneville formations indicates a 

marked lowering of the lake, as concluded by Gilbert 

( 1890), 1-Iunt, Varnes, and Thomas ( 1953), and Morrison (Art. S33). This in turn suggests that the ice 

yeceded to the cirques but did not disappear in the 

interval separating deposition of the two moraines. 

Outwash gravels deposited during the final recession 

of Bull Lake glaciation extend to the Provo shorelinethe upper limits of the Provo for.mation (Hunt, Varnes, 

and Thomas, 1953). Thus, the entire sequence of deposits of Lake Bonneville as recognized by Gilbert 

(1890) was deposited during Bull Lake glaciation. 

A mature zonal soil formed on all exposed deposits 

· during Bull Lake-Pinedale interglaciation, at which 

time it has been inferred that Lake Bonneville was essentially dry (Richmond, l\1orrison, ·and Bissell, 1952: 

~forrison, Art. 33:1). 

The third glaciation of the mountains--correlated 

with the Pinedale glaciation of '\Vyoming--comprises 

three sets of moraines in the middle and upper parts 

of Little Cottonwood Canyon and its tributaries at average altitudes of 6,570, 7,220, al)d 9,195 feet. These mark 

a maximum advance and two minor readvances or halts 

during recession of the ice that are believed to have been 

separated by only brief interstadial intervals. No direct stratigraphic tie between these deposits and those 

of Lake Bonneville can be made, but probably they cnn 
D-128 GEOLOGICAL SURVEY RESEARCH 19 61 

be correlated with three post-Provo rises of the lake disr.overed by l\1orrison ( 1961) at successively lower altitudes below the Provo shoreline. 

The glaciers probably disappeared entirely from the 

mountains and the lake was again dry during the "altithermal age" of Antevs ( 1948). Subsequently, two 

sets of small moraines or rock glaciers have formed in 

the cirques. These represent the Temple Lake and historic stades 1 of neoglaciation 2 , both of which occurred 

during the "little ice age" of Matthes ( 1939). 

Numerous workers, including Gilbert ( 1890, p. 309-

:no), Atwood (1909, p. 92-93), Antevs (1945, p. 74-77), 

Blackwelder (1931, p. 915-916), Ives (1950, p. 115), 

and I-Iunt, Varnes, and Thoinas ( 1953, p. 41), have coneluded that the second rise of Lake Bonneville-that 

which attained the Bonneville shoreline and was lowered by erosion at its outlet to the Provo shoreline-was 

correlative with the last Pleistocene glaciation of the 

mountains. The present evidence indicates the deposits 

of the rise to the Bonneville shoreline and of the stillstand at the Provo shoreline are correlative with the 

later of two stades of Bull Lake glaciation. Only certain lo,Yer fluctuations of the lake following post-Provo 

dessication and preceding the "altithermal age" are corI'elative with the last or Pinedale glaciation. 

The Pinedale glaciation, on the basis of a radiocarbon 

date of 27,000±800 years from its outer moraine in 

,Jackson Hole, 'Vyo. (Rubin and ·Alexander, 1958) 

seems to include all of the 'Visconsin stage as defined 

by Leighton (1933), for the Farmdale loess of Illinois 

is probably not much older than 26,100±600 years 

(Frye and 'Villman, 1960). The deposits of the Bull 

Lak.; glaciation are stratigraphically lower than those 

of the Pinedale, and are separated from them by de1 A stad:e ts defined as a cllmUJttc episode wtthtn a glaciation d1uring 

which a secondary advance of glaciers took place (American Commission 

o11 ~tt·ati~raphic Nomenclaturt>, 1961, p. 660. 

!l The n.eoglaciatton is hereby defined as the last glaciation tn the 

Rocky Mountain region. It ts of post-Pleistoeene (Recent) age. 

glaciation, erosion ancf the development of a mature 

zonal soil. No such pronounced climatic break has 

been recognized in the classica1 succession of 'Visconsin deposits in Illinois. Thus, it may be concluded 

· that the deposits of the two high-level rises of Lake 

Bonneville is r~cognized by Gilbert ( 1890), including 

those of the stanclstill·at the Provo shoreline, are older 

than 'Visconsin. 

REFERENCES 

American Commission on Stratigraphic Nomenclature, 1961, 

Code of stratigraphic nomenclature: Am. Assoc. Petroleum 

Geologists Bull., v. 45, no. 5, p. 645-665. 

.Antevs, Ernst, 1945, Correlation of Wisconsin glacial maxima: 

Am. Jour. Sci., n.s., v. 243-A, Daly volume, p. 1-39. 

--1948, Climatic changes and pre-white man, in The Great 

Basin, with emphasis on glacial and postglacial times : 

Utah Univ. Bull., v. 38, no. 20, p. 167-191. 

Atwood, ·w. ·w., UlO!), Glncintion of the Uintn nnd lV:tsntch 

Mountains: U.S. Geol. Survey Prof. Paper 61, 96 p. 

Blackwelder, Eliot, 1931, Pleistocene glaciation in the Sierra 

Nevada and Basin Ranges: Geol. Soc. America Bull., v. 42, 

no. 4, p. 865-922. 

Frye, J. C., and 'Villman, H. B., 1960, Classification of the Wisconsinian stage in the Lake Michigan glacial lobe : Illinois 

State Geol. Survey Circ. 285, 16 p. 

Gilbert, G. K., 1890, Lake Bonneville: U.S. Geol. Survey Mon. 1, 

438 p. 

Hunt, C. B., Varnes, H. D., and Thomas, H. E., 1953, Lake 

Bonneville-geology of northern Utah Valley, Utah: U.S. 

Geol. Survey Prof. Paper 257-A, 99 p. 

Ives, R. L., 1950, Glaciations in Little Cottonwood Canyon, 

Utah: Sci. Monthly, v. 71-, no. 2, p. 105-117. 

Leighton, M. M., 1933, The naming of the subdivisions of the 

Wisconsin glacial age: Science, v. 77, p. 168. 

Matthes, F. E., 1939, Report of Committee on Glaciers: Am. 

Geophys. Union Trans., 20th Ann. Meeting, pt. 4, p. 518-523. 

Richmond, G. M., Morrison, R. B., and Bissell, H. J., 1952, Cor~ 

relation of the lute Quaternary deposits of the La Sal 

Mountains,· Utah and of Lake Bonneville and I.nhontan by 

means of interstadial soils [abs.] : Geol. Soc. America Bull., 

v. 63, p. 1369. 

Rubin, Meyer, and Alexander, Corrine, 1958, U.S. Geological 

Survey radiocarbon dates IV: Science, v. 127, p. 1476-1487. 

335. ·MAGNITUDE OF THRUST FAULTING IN NORTHERN UTAH 

By MAx D. CRITTENDEN, Jn., MENLO PARK, CALIF. 

· The Bannock, 'Villard, Charleston, and N ebo faults 

a.re part of a discontinuously exposed belt of overthrusts that extends from Montana and Idaho to southeastern Nevada. So far as known, all are rooted to 

the west, and all have brought thicker basin-type facies 

over thinner shelf-type rocks to the east. The resulting 

contrast in thickness or character is evident in rocks 

ranging in age from Prec~mbrian to Permian. 

In Utah, the· northernmost segment of this thrust 

belt extends from a branch of the Bannock thrust near 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-129 

Bear Lake to the Willard thrust on the crest of the 

'Vasatch Range near Ogden. Together these thrusts 

define an overriding structural block that is characterized by a thick basal Cambrian quartzite resting on 

at least 6,000 feet of Precambrian sedimentary rocks. 

The block beneath the thrusts is characterized by a 

thin basal Cambrian quartzite, which rests directly on 

highly metamorphosed Precambrian rocks older than 

those of the upper plate. The structure within the 

block is that of a simple syncline; the same Cambrian 

formnJ.ions cn.n be traced around the fold,. and serve 

to establish structural continuity from one thrust to the 

other. 

The southern segment of the belt of overthrusts consists of the Charleston and N ebo thrusts, which together outline a bulging lobe of basin:-type rocks that 

extends eastward to the edge of the Uinta Basin. The 

overriding block in this segment is characterized by 

some 30,000 feet of beds between the I-Iumbug formation o:f 1\1ississippian age and the Park City formation 

of Perm ian age, whereas in the autochthon to the east 

the same stratigraphic interval contains less tha.n 2,000 

feet of beds. 

The structurnl continuity between the northern and 

southern segments of this belt is speculative because 

neither the thick unmetamorpho.sed Precambrian sedimentary rocks of the northern block nor the thick Pennsylvanian nnd Permian rocks of the southern block ext·end unbroken from one block into the other. Nevertheless, parts of the Oquirrh formation have been 

identified by Olson (1956) in the Promontory Range, 

where they are in sequence above thick unmetamorphosed Precambrian rocks. This relation serves to 

eshtblish the kinship of the ~wo blocks, though H1e 

thrust itself is concealed. The trace shown on figure 

335.1 is regarded as the likeliest of several possibilities. 

Antelope Island, underlain largely by highly metamorphosed Precambrian rocks, is regarded as autochthonous. The thin (288-foot) wedge of Precambrian 

slate, dolomite, and tillite reported there by Larsen 1 

may be the landward edge of a depositional basin that 

origit1ally Jay to the west. Overlying tan or pink 

conglomerutic quartzites are believed to be equivalent" 

to the Tintic quartzite and are therefore not of Precambrian age. Deformation of these quartzites into nearly 

isoclinal folds in which there was sufficient axial plane 

shearing to produce marked stretching of quartzite 

pebbles, suggests that the thrust plane passes close to 

the northwestern tip of Antelope Island, and that the 

thick sequences of unmetamorphosed Precambrian 

rock on Fremont Island and Promontory Point are 

nl1ochthonous. 

1 Larsen, W. N., 1957, Petrology and structure of Antelope Island. 

Dn~ls County, Utnh: Utah Unlv., unpublished Ph. D. thesis. 

Estimates of the displacement on thrusts of this belt 

range from as little as 12 miles (Hintze, 1960, p. 2062) 

to as much as 75 miles (Eardley, 1951, p. 330). The 

first estimate is based entirely on observations within 

the allochthon, and hence does not give information 

about the total movement with respect to the autochthon. The second, though larger than those derived 

below, appears to be possible from stratigraphic 

evidence. 

The minimum displacement of the northern block is 

best estimated from the relations of its characteristic 

unmetamorphosed Precambrian sedimentary rocks. 

If, as suspected, Antelope Island represents the eastern- · 

most edge of the principal depositional basin, the 7,000-

foot sequence of these Precambrian rocks exposed east 

of Ogden must have come from somewhere west of the 

present site of the island, a distance of at least 30 miles. 

Lack of information as to the rate of thickening makes 

it impossible to estimate hoi' much farther west they 

may have originated. 

Other evidence is obtained from the relative effects of 

the Devonian-M:ississippian unconfor1nit"y (fig. 835.1,.p. 

D-130), as expressed by the thickness of beds between 

it and the top of t"he Tintic or it·s stratigraphic equivalent, the Brigham quartzite. The 6,000-foot isopach in 

the thrust block meet"s the "Tillard thrust opposite the 

2,000-foot isopach in the footwall. Projecting the isopachs eashntrd at" t"he same rat"e as those· known within 

the allochthon suggests about" 40 miles of displacement. 

on the thrust. A similar result is obtained from the 

data for rocks of Mississippian age (fig. 335.2). 

Isopachs representing some 4,000 to 5,000 feet of beds 

in the overriding block meet the Willard thrust opposite 

the line representing some 1,800 feet of beds in the 

autochthon. Here, also, a movement of some 40 miles 

is required to restore the continuity of the two sets of 

isopachs. 

Displacement"s of the Charleston-Nebo block can best 

be estimated by reconstruction of the general form of 

the Oquirrh basin (fig. 335.3). As there is no evidence 

for the configuration of the now-destroyed east half, its 

general outline and the maximum slopes have been made 

approximately symmetrical with the west half. On 

such a basis, a displacement of about 40 miles is likely. 

Obviously, different assumptions regarding configuration and slope would yield values ranging from half to 

twice this amount. 

REFERENCES 

I~ardley, A. J., 1951, Structural geology of North America: New 

York, Harper & Bros., 624 p. 

Hintze, Lehi, 1960, Thrust-faulting limits in western Utah 

[abs.]: Geol. Soc. America Bull., v·. 71, no. 12, p. 2062. 

Olson, R. H., 1956, Geology of Promontory Range, in Utah Geol. 

Soc. Guidebook to the geology of Utah, no. 11 : p. 41-75. 
D-130 GEOLOGICAL SURVEY RESEARCH 1 9 6 1 

10 0 10 20 30 MILES 

EXPLANATION 

Area underlain by thick sequence 

Isopach. inten~al1000feet 

[JJ]JJ] 

Area underlain by thin sequence Isopach inten~al 1000 feet 

Steep fault 

Dashed where in/erred 

Thrust fault 

Dashed where in/erred, dotted where concealed 

Saw teeth. on upper plate 

--2000---··· 

Isopach connecting points where rocks between Tintic quartzite and 

Devonian-Mississippian unconformity are of equal thickness 

Dotted to show former extent across autochthon 

Displacement needed to connect corresponding isopachs 

Location of measured section 

Outside number refers to reference listed in table; 

number in circle is thickness in thousands of feet 

FIGURE 33ii.l.-Displacemeut on \Villard and Bannock thrusts 

based on thickness of beds between top of Tintic quartzite 

and the Devonian-Mississippian unconformity. 

10 0 10 20 30 MILES 

EXPLANATION 

Area underlain by thick sequence Isopach. inten~al 1000 feet 

Area underlain by thin sequence Isopach interval 200 feet 

Steep fault Dashed where inferred 

~~~ ........ Thrust fault Dashed where inferred, dotted where concealed 

Saw teeth on upper plate 

--3000----

lsopach connecting points where Mississippian rocks are. of equal thickness Dashed where inferred, dotted to show 

proiected position across autochthon 

Displacement needed to connect corresponding isopachs 

r.;-.22 

I.:Y 

Location of measured section 

Outeide number refers to reference listed in table; 

number in circle is thickness in hundreds Qj' feet 

FIGURE 335.2.-Displacement on Willard and Ranmx-k thru:-;ts 

based on thickne:o;s of l\Ii~si~~ippian rocks. 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-131 

10 0 10 20 30 MILES 

EXPLANATION 

Ill 

Area underlain by thick sequence of Oquirrh formation 

Area underlain by thin sequence of Round 

Valley limestone and Weber formation 

Steep fault 

Dashed where i71ferred 

~ ............... . Thrust fault 

Dashed where i7\{erred, dotted where concealed 

Saw teeth on upper plate 

--4000-----

Isopach connecting points of equal thickness of beds in 

Pennsylvanian-Permian interval· Dashed where inferred, dotted to sl,tow 

formsr extent acro1111 autochthon. 

laopach inter11al 1000/eet 

Displacement needed to connect corresponding isopachs 

r.;-..'6 

\:.V 

Location of measured section Outaide number r~er11 to localitiea liated in table; 

number in circle ill thickne1111 in thouaanda of feet 

TABLE 335.1.-References to measured section given on figures 

335.1-335.3 

No. on map Reference 

Baker, A. A., 1947, U.S. Geol. Survey Oil and Gas 

lnv. Chart 30. 

2 Unpublished data. 

3 Baker, A. A., and Crittenden, M. D., 1961, U.S. 

Geol. Survey Geol. Quad. Map GQ-132. 

4 Baker, A. A., Huddle, J. W., and Kinney, D. M., 

. 1949, Am. Assoc. Petroleum Geologists Bull., v. 

33, no. 7, p. 1161-1197. 

5 Bissell, H. J., 1952, Am. Assoc. Petroleum Geologists 

Bull., v. 36, no. 4, p. 575-634. 

6 Calkins, F. C., and Butler, B. :S., 1943, U.S. Geol. 

Survey Prof. Paper 201, 152 p. 

7 Cohenour,· R. E., 1959, Utah Geol. and Mineralog. 

Survey Bull. 63, 200 p. 

8 Crittenden, M. D., unpublished data. 

9 Demars, L. C., 1956, Brigham Young Unh. Research 

Studies, v. 3, no. 2. 

10 Disbrow, A. E., 1957, U.S. Geol. Survey Mineral lnv. 

Field Studies Map MF-131. 

11 Eardley, A. J., 1944, Geol. Soc. America Bull., v. 55, 

no. 7, p. 819-894. 

12 Gilluly, James, 1932, U.S. Geol. Survey Prof. Paper 

173, 171 p. 

13 Granger, A. E., 1953, U.S. Geol. Survey Cfrc. 296, 

14 p. 

14 Hooper, W. G., 1951, Geology of the Smith and 

Morehouse-South Fork area., Utah Univ., unpublished Master's thesis. 

15 Huddle, J. W., and McCann, F. T., 1947, U.S. Geol. 

Survey Circ. 16, 21 p. · 

16 Morris, H. T., 1957, Utah Geol. Soc. Guidebook to 

the geology of Utah, no. 12, p. 1-56. 

17 Olson, R. H., 1956, Utah Geol.. Soc. Guidebook to 

the geology of Utah, no. 11, p. 41-75. 

18 Rhodes, J. A., J 955, Brigham Young Univ. Research 

Studies, v. 2, no. 4. 

19 Rigby, J. K., 1958, Utah Geot ~oc. Guidebook to 

the geology of Utah, no. 13, p. 1-134. 

20 Roberts, R. J., and Tooker, E. W., unpublished data. 

21 Sando, W. J., Dutro, J. T., and Gere, W. C., 1959, 

Am. Assoc. Petroleum Geologists Bull., v. 43, no. 

12, p. 2741-2769. 

22 Williams, J. S., 1958, Utah Geol. and Minera.log. 

Survey Bull. 64, 98 p. 

23 Young, J. C., 1955, Utah Geol. and Minera.log. 

Survey Bull. 56, 110 p. 

FIGURE 335.3.-Displacement on Charleston and Nebo thrusts 

based on thickness of Pennsylvanian and Lower Permian 

rocks. 
D-132 GEOLOGICAL SURVEY RESEARCH 1 9 61 

336. SUBDIVIDING THE JORDAN VALLEY GROUND-WATER BASIN, UTAH 

By I. WENDELL MARINE, Norman, Okla. 

Work done in cooperation with the Utah State Enginee1· 

,Jordan Valley, Utah, is a structural basin on the 

eastern margin of the. Basin and Range physiographic 

province (index map on fig. 336.1). The basin has 

been partly filled with unconsolidated and semiconsolidated material of Tertiary and Quaternary age. This 

material has been deposited by strea.ms, lake currents, 

mudrock flows, glaciers, and '"ind, and c.onsists c.hictly 

of mixtures of boulders, gravel, sand, silt, c.lay, and 

limestone. During both Tertiary and Qua.ternary 

times, periods of subaeria-l erosion and deposition ha.ve 

alternated with periods when lakes of different depths 

have occupied all or part of the valley. At ma.ny times, 

subaerial erosion and deposition were taking place in 

some parts of the va.1ley while erosion or deposition in 

lakes was taking place in other parts. Stream discharge 

fluctuated through wide ranges caused by variations in 

climate, especially in Pleistocene time. At first inspection, the basin deposits appear to be a disordered array 

of heterogeneous rock material which resulted from the 

variety of the processes of sedimentation that have been 

active, from 'the number of unconformities and the 

nuied relief on their surfaces, and from the occurrence 

of several faults within the valley fill. No widespread 

continuous aquifers were found to exist. 

Despite the complex sedimentary history of the basin, 

it has been found possible to divide the tT ordan Valley 

into hydrologic units on which the management and 

development of ground water might be based. The 

central problem w·as to determine whether bodies of 

material 'Yith simila.r hydrologic properties existed and, 

if so, to portra.y them adequately on a ma.p. Studies of 

the physiography, drillers' logs, gravel percentages in 

well cuttings, specific capacities of wells, and water 

quality provided satisfactory criteria for dividing the 

valley into six natural ground-,vater districts (fig. 

336.1) whose boundaries are marked on the surface by 

some physiographic fenture. Several of these districts 

u.re divided into two or more subdistricts on the basis 

of less obvious differences than those that distinguish 

the districts. Generally the subdistrict boundaries are 

not distinguished by physiographic features of any sort. 

Fc;>r the water user, the important differences. in these 

districts are the specific. capacities of the wells and the 

quality of '"aterin these wells (table 336.1). The degree 

to which surface boundaries can be based on physiography aids in describing the districts, even though 

some of the subsurface boundaries are more gradational than the sha.rp physiographic features on the 

surface. 

A qua.litative study of drillers' logs indicated that the 

overall lithologic aspect of the sediments could be used 

to differentiate the districts and subdistricts, and a 

gravel-percentage map showed that coarse material generally predominated in some areas and was relatively 

rare in others. A map of the specific capacity of largediameter wells showed that each district or subdistrict 

has aeharacteristic range in specific capacity. The differences in specific capacity of wells between areas were 

great enough to render unimportant such factors as well 

diameter, length of pumping test, amount of drawdown, 

length of the perforated section, amount and nature of 

development, and other factors that affect the accuracy 

of this determination. A map of the dissolved-solids 

content in ground water and a comparison of the major 

constituents showed that, in general, the ground-water. 

districts and some subdistricts have a distinctive range 

in water quality. 

The differences bet,veen the districts are due to local 

differences in the seclimenta.ry and tectonic events of the 

valley. For example, the East Lake Plain district has 

dropped repeatedly relative to the East Bench district 

along the East Bench fault which forms their common 

boundary. Lakes frequently covered the East Lake 

Plain district but only rarely extended onto the East 

Bench district which, for a long time, has been topographically higher. The East Lake Plain district, 

therefore, is underlain by thick sequences of lake sediments, whereas subaerial sediments predominate in the 

East Bench district. Another example is the Cottonwoods district, which has also dropped relative to the 

East Bench district but has had a large supply of coarse, 

well-sorted sediment delivered to it by the two Cottonwood Creeks. These two creeks have deposited channel 

and alluvial-fan deposits in times of low lake levels and 

have built large deltas at times of high lake levels. The 

coarse, well-sorted deposits in the district are highly 

permeable and permit the development of wells of high 

specific capacity. The lithology and high permeability 
N. 

T. 

2 

s. 

T. 

3 

s. 

T. 

4 

s. 

SHORT PAPERS IN THE GEOLOGfC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-13'3 

Salt 

R. 3 W. 

I 

a: 

a:: 

:::> 

0 

MIDDLE 

,-- -- ·-l I 

l~t~jM~~ I JORDAN ~ I : I VALLEY ~ I I I 

I BASiN I I AND COLORADO I ; RANGE PLATEAUS : 

I 

I ! 

L. __ _j 

INDEX MAP OF UTAH 

R. 2 W. R.l W. R.l E. 

NORTHWEST 

LAKE PLAIN 

!DISTRICT 

WEST 

() 

~ '?~ 

COTTONWOODS ~ ~><~~c~reex:lk 

~.~an~ .. -~ llXXIKX><:xx:t 

North 

Subdistrict 

SLOPE ~ .. / 1 DISTRICT ~ 

~ ----~.. \j~ _.. ,,---- ~ Jfl1l '-w~Cre~ek 

--.. ---· U ~···~ c~~ :i' 

South Fan )f SOUTHEAST ~ 

Bingham 

--...-~---

- DISTRICT ~ 1 

Subdistrict ~ DISTRICT 

A~~ 

-·· 

l!...,IGUHE 33().1.-l\:lap of Jordan Valley, Utah, showing ground-water districts and subdistricts. 
D-134 GEOLOGICAL SURVEY RESEARCH 1 9 6 1 

of the sediments probably account for the fact that the 

water of the Cottonwoods district contains less dis-

_solved solids, average 250 parts per million, than the 

water of ai~Y other district in Jordan Valley (table 

336.1). 

The criteria used to divide the complex sedimentary 

basin of Jordan Valley into ground-water districts can 

be used to divide areas of similar complexity and 

thereby aid in water management of such areas, and in 

predicting the characteristics of future wells. 

District or subdistrict Physiography 

TABLE 336.1.-0ccurrence of grot.-nd u·ater in Jordan Valley, Utah 

Material Type of dcpm:lts 

Approxi'llate 

thickness 

away from 

boundaries 

Specific Dissolved solids (parts capacity per million) (gallons 

(feet) 

Gravel 

away fl'om 

boundaries 

(percent) per minute 

per foot) Minimum Average Maximum 1 

East Bench·---------~- Pediments and 

alluvial fans 

overlain in some 

places by takeshore features. 

East Lake Plain: 

Boulders and clay 

with some gravel 

and sand, mostly 

reddish brown. 

Sandstone, silt 

stone, and limestone of Mesozoic 

age in pediment 

areas. 

Main part_ ____ . ____ Lake plain overlain Blue-gray lakein some places by bottom clays and 

alluvial fans or silts with disconabandoned flood tinuous gravel 

plains. lenses. 

City Creek Fan ... Alluvial fan _________ Boulders and 

North Bench ______ Bajada overlain by 

lake shore 

features. 

Cottonwoods __________ Large lake-shore 

features cut by 

abandoned 

stream channels. 

Sou thcast_ . ______ .. _.. Lake-shore features. 

In south,· dissected pediment. 

West Slope ____________ Gentle eastward 

slope overlain by 

lake shore features. Pediments near 

mountains. 

gravel. 

Boulders, gravel, 

sand, and clay. 

Brown sand and 

gravel interlayered with 

blue-gray clay. 

Gravel, sand, ancl 

clay. 

Deposits of mudrock flows and 

ephemeral 

streams. 

Lake-bottom sediments and probably turbiditycurrent deposits. 

0-500 ____ ~----- 50-100 _______ 20--100 ______ _ 

>1,000 in <25. ________ <5 _________ _ 

most places. 

Alluvial fan _________ 500 _______ ~---- 50-100 ....... 50-50Q ______ _ 

Deposits of mudrock flows. 

Alluvial fans of 

perennial streams 

interlayered with 

lake-bottom 

deposits and 

deltas. 

Unknown but 

>I,OOO 

everywhere 

Unknown but 

>1,200 in 

places. 

Mostly 

50-100 

but in the 

north and 

south 

<25. 

Upper area 

50-200; 

lower area 

5-40. 

>so _________ --------------

320 600 685 

251 490 71i4 

253 530 761 

71i 250 651 

184 (2) I, 004 

365 640 31,240 

South Fan _____________ do _______________ Bouiders, gravel, Alluvial fans ________ 200-500 .. ______ >25, >50 in 5-30 _________ ------------ ---------- ------------

sand, and clay. most 

places. North PedlmenL ...... do _______________ Tertiary clay, silt, Lake-bottom sedi- Unknown but 

>1,400. 

<25 _________ <3 __________ ------------ ---------- ------------

Northwest Lake 

Plain: 

Lake plain overlain 

in places by flood 

plains. · 

Main part_ _____________ do .. --------~----

Mid-Jordan.~----- _____ do ______________ _ 

South Margin _____ ..... do ______________ _ 

North Oquirrh .... _____ do ______________ _ 

and limestone. 

Blue-gray clay with 

thin sand lenses. 

Sand and gravel interlayered with 

clay. 

Sand, gravel, and 

clay. 

0-300 feet of blue 

lake clay underlain by coarse 

angular gravel. 

ments. 

Lake-bottom sedi- 2,30Q __________ Q ____________ 

ments. 

Channel, flood Unknown but 25-50 ________ 

plain, and lake >775. 

deposits. 

---------------------- 500. ___________ 25-SQ ________ 

Lake deposit under- 15o-800.------- 25-50.-------

lain by talus or 

brecciated bedrock. 

1 Excluded from this column are maxima caused by isolated contamination or isolated occurrences of thermal water. 2 Not meaningful. 

Low ________ 

<20 _________ 

10-20 ________ 

30-750.------

3 Exclusive of general contamination of beds less than 300 feet deep by Jordan River water in the area where this is used for irrigation. 

492 1, 640 3, 600 

244 380 798 

840 1, 150 1, 510 

2,485 6,860 10,800 
~· 

SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-135 

337. POTASH-BEARING EVAPORITE CYCLES IN THE SALT ANTICLINES OF THE PARADOX BASIN, 

COLORADO AND UTAH 

By RoBERT J. RITE, Salt Lake City, Utah 

Potash was discovered in the Paradox basin of southmtst Utah a.nd southwest Colorado in 1924 (Dyer, 1945; 

p. 56), but the full extent and richness of the deposits 

were not recognized until the last decade when improved logging techniques and more closely spaced 

drill holes enabled a more complete investigation of the 

deposits. 

The potash deposits occur in the "saline facies" of 

the P~tradox member of the Hermosa formation of 

Pennsylvanian age. The areal extent of the "saline 

facies" in the Paradox basin is about 11,000 squa.re 

miles and nearly two-thirds of this area. is underlain 

by potash deposits (fig. 337.1). 

The "saline facies" originally may have been about 

7,000 feet thick, but locally it is now grea.tly thickened 

in intrusive salt anticlines in some of which as much 

as 14,000 feet of saline rocks have been drilled. 

A recent detailed study of the stratigraphy of the 

"saline fn.cies" resulted in an informal system of nomenclature in which the halite units of the evaporite 

cycles are distinguished numerically (I-Iite, 1960). 

This system is used by the writer in the correlation of 

potash deposits, which are widely distributed in the 

salt basin. 

The "saline facies" consists of at least 29 evaporite 

cycles. Each cycle, if complete, in ascending order of 

deposition consists of: (1) limestone, (2) dolomite, (3) 

anhydrite, and ( 4) halite "·ith or without potash salts. 

The sequence is then repeated in a re,·erse order of: (iJ) 

anhydrite, (2) dolomite, and ( 1) limestone to complete 

the cycle (fig. 337.2). Potash-bearing cycles generally 

exhibit an asymmetrical form with the potash occurring near the top of unit 4. Units 1, 2, and 3 of each 

cycle include some clastic material that commonly is 

euxi11tc black shale, mudstone, and siltstone. A complete vertical succession in any one cycle is not everywhere present because of a lateral gradation from a 

super-saline or saline facies in the basin deep to a 

limestone facies on the basin shelf (fig. 337.2). Thus, 

in the basin deep (line X of fig. 3:37.2) only units 3 and 

4 may be present; while at some point intermediate 

between t'he basin deep and basin shelf (line Y of fig. 

337.2) all unit's may be present and the vertical succession is complete. 

In ttbout 18 of the 29 evaporite cycles, chemical sedimentation proceeded to the point of potash precipitation. Of these 18 cycles, 11 contain potentially 

valuable potash deposits. These are found in salt beds 

5, 6, 9, 13, 16, 18, 19, 20, 21, 24, and 27 of Hite (1960). 

In several of these cycles tlie average content for specific intervals of some deposits may exceed 30 percent 

K20. Only two potash salts, sylvite (I(Cl) and 

carnallite (KCl· ~igCb · 6H20), are present in large 

quantities. Minor amounts of poly halite (2CaS04 · 

lligS04 · K2S04 ·2I-I20), .kieserite (:~1gS04 · H 20), and 

rinneite (FeCl 2 ·3J(Cl·NaCl) hnve been reported. 

ll1any of the potash deposits are extensive. Perhaps 

the most noteworthy of these is the deposit in salt bed 

19. This deposit has been traced from Crescent J unct.'ion, Grand County, Utah, in the northwestern end of 

the salt basin to northern Montez.uma County, Colo.-

a distance of nearly 110 miles-and may prove to be 

one of the thickest in the world. In the northwestern 

part of ~1oab Valley anticline (fig. 337.1), where the 

salt structure is nonintrusive, the potash deposit is 420 

feet thick, ~l.nd consists mostly of carnallite and halite. 

However, the deposit shows lateral changes in mineralogy as the carnallite gives place to sylvite (fig. 337.3, 

p. D-138). The presence of this deposit in an area extending from Cane Creek anticline to Salt Valley 

anticline (fig. 337.3) solves an enig-ma which has discouraged prospecting in the Salt Valley anticline area 

for many years. The thick .deposit of potash found 

in the Defense Plant Corporation :Reeder well 1 previously was considered a secondary thickening or enrichment brought about by salt flow in the salt 

anticline.· Such an origin can now be ruled out because 

t'he deposit shows thickness and mineralogic ch'aracter- · 

istics that are similar throughout a large surrounding 

area. 

The potash deposits of the "salinH facies" are found 

at depths ranging from 1, 700 to 14,000 feet below the 

surface. At present they are minable only in salt anticlines. Recent exploration has been concentrated on 

nonintrusive folds such as the Cane Creek anticline, 

the northwestern part of Moab Valley anticline, and 

Lisbon Valley anticline {fig. 337.1). Data on these 

structures are fairly complete, and at the Cane Creek 

anticline the first shaft in the potash field is expected 

to he started sometime in 1961. 

In the nonintrusive ·salt anticlines the mm1mum 

depths to the top of the salt range from 1,600 to 2,400 

feet and depths to the uppermost potash deposits of 

economic importance may range from 1,800 to 4,000 
D-136 GEOLOGICAL SURVEY RESEARCH 19 61 

GRAND 

UTAH 

ARIZONA 

I 

I I MESA 

I 

EXPLANATION 

..----- Approximate limits Of the salt 

facies of the Paradox member of 

the Hermosa formation 

.,0 -o-o_..., 

Approximate limits of major potash zones in the "saline facies" of the 

Paradox member of the Hermosa 

formation 

Salt anticline 

B 

Ao__.-"~ oC 

Line of section 

0 10 

DOLORES 

M. 0 N T E Z U M .A 

20 MILES 

FIGURE 337.1.-Distribution of halite and potash in the Paradox basin. 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-137 

sw 

Limestone • 

• Dolomite 

~ 

~ 

Anhydrite 

~ 

~ 

Halite 

Ill 

Potassium salts 

-

Clastics 

NE 

.. I 

l!..,roum~ 337.2.-A schematic section through an evaporite cycle of the Paradox member of the Hermosa formation. 

(Lines X and Y are described in text.) 

feet. The potash deposits of saJt beds 5 and 9 appear 

most favorable for exploitation. On the Cane Creek 

anticline, mine development will probably proceed in 

these two deposits between the depths of 2,400 and 

3,500 feet. 

Drill-hole information concerning intrusive salt anticlines, however, is meager and most of it has come from 

oil and gas test wells. Several potash test holes were 

drilled on the Salt Valley anticline but unfortunately 

no gamma ray-neutron logs were obtained except from 

the Defense Plant Corporation well. Such logs are 

necessary to provide adequate stratigraphic control for 

correlation between holes. 

In the intrusive salt anticlines the "saline facies" is 

near the surface; the uppermost salt bed may be less 

than 500 feet deep. The relatively thick and highgrade potash deposits in salt beds, 18, 19, 20, and 21. 

although beyond the reach of present conventional mining methods in the nonintrusive structures, are upfolded within the intrusive anticlines to more favorable 

depths. 

Variable degrees of salt dissolution and removal are 

evident in nearly all of the salt anticlines. In the nonintrusive structures dissolution has removed as much 

as 1,500 feet of salt. In the intrusive salt anticlines the 

604493 0-61.--10 

effect of salt solution may be even more pronounced. 

Thus, by a combination of structural elevation and salt 

dissolution, a potash deposit low in the "saline facies" 

may be brought near the surface. Such deposits might 

well be found at depths of less than 500 feet. 

Recognition of widespread units in the "saline facies" 

of the Sa1t Valley anticline indicates that the potash 

deposits in this and other intrusive salt anticlines probably occur as identifiable continuous bodies. These 

bodies would no doubt show a high degree of crenulation and faulting. In this respect the intrusive salt 

anticlines of the Paradox basin n.re probably similar 

to· the salt stocks of Germany where stratigraphic sequences are recognizable in spite of intense tectonic deformation, and where potash salts have been successfully mined for more than a century. 

REFERENCES 

Dyer, B. ,V., 1945, Discoveries of potash in eastern Utah: Am. 

Inst. Mining Metall. Engineers 'I'ech. Pub. 1755, Mining 

Technology, v. 9, no. 1, p. 56-61. 

Hite, R. J., 1960, Stratigraphy of the saline facies of the Paradox member of the Hermosa formation of southeastern 

Utah and southwestern Colorado, 'in Four Corners Geol. Soc. 

Guidebook Field Conf. n~3, Geology of the Paradox basin 

fold and fault belt, 1960: p. 86-89. 
D-138 GEOLOGICAL SURVEY RESEARCH 19 61 

A B C 

l~oo~•:-----------9 Miles---------~~-------- 22 Miles---------)~~ 

CANE CREEK ANTICLINE SEVEN MILE ANTICLINE SALT VALLEY ANTICLINE 

Texas Gulf Producing Well Deli-Taylor Oil Corp. Well2. Defense Plant Corp. 

1-X. Sec. 36, T. 26 S., Sec.l8, T. 25 S., R. 21 E. Reeder 1. Sec. 4, T. 22 S., 

R. 20 E. Grand County, Grand County, Utah R. 19 E. Grand County, 

U~h U~h 

GAMMA RAY RESISTIVITY 

: t 

Note: Interpretation based ... · ·on gamma-ray, neutron, . · ::and resistivity logging, : :plus drill cores from the · · 

: : Defense Plant Corp. well : : 

.GAMMA RAY· 

Shale-anhydrite "C" marker 

.A~········································ :::: J:::::: ·s~lt.26:::::::::::::::: :::::.:::::::::::: 

NEUTRON 

6100:::: 

GAMMA RAY NEUTRON 

3700 

. 3800 

··•••••••·····~;~LAN~ EJ 

Halite 

Halite and sylvite 

Halite and carnallite 

FIGURE 337.3.-Potash-bearing evaporite cycle of the Paradox member "saline facies". Datum· is mean sea level. 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-139 

338. CRETACEOUS ROCKS IN LEA COUNTY, NEW MEXICO 

By SIDNEY R. AsH and ALFRED CLt:BSCH, .Jr., Albuquerque, N. ~1ex., and 'Vashington, D.C. 

Work done in coopera.tion with the Sta.te Engineer of New Mea:ico a.nd the New llfea:ico Institute of Mining a.nd Technology, State Bu·rea.u of Mines and llfinera.l Retwu.rces Division 

Rocks of Cretaceous age are exposed at only two localities in Lea. County, but their subsurface distribution is extensive. The outcrop at North Lake (fig. 

R~8.1) has been known for many years (Theis, 1934, 

p. 147; 1938, p. 124; Conover and Akin, 1942, p. 285-

288; Lang, 1947, p. 1476; and Dane and Bachman, 

1D58), but it has not been related to the Cretaceous 

rocks in the subsurface. The Cretaceous rocks near 

Eunice were uncovered in the course of quarrying 

gravel from n pit about 3 miles east of town; apparently they hnve not been described previously. 

EXPOSURES 

T'he Cretaceous rocks exposed at North Lake consist 

of dark-gray siltstone and thin interbedded stringers 

of 1 i mestone (fig. 338.2). Several of the limestone 

stringers wedge out laterally into siltstone. In the 

lower part of the section that was measured the stringers are light-brown crystalline limestone; in the upper 

part of the section they are light gray and fine grained. 

Both the siltstone and limestone weather yellow. 

The fossils listed below were collected from the outcrop in sec. 32, T. 10 S., R. 34 E., north of the section 

shown on figure 338.2 and were identified. by T. '''· 

Stanton (written communication, 1935): 

G1•yphaea oorrugata Say 

Eroogyra teroana Roemer 

Plioat'lda cf. inoongrua Conrad 

E roogy1·a 7)leroa Cragin 

Pecten (Neithea) teroanu"({ Roemer~ 

S erpula ( ~) sp. 

These fossils indicate that the enclosing rocks are of 

Early Cretaceous age. 

Eroogyra teroana, G1·yphaea oorrugata, and Plioatula 

sp. have been found in the Tucumcari shale in eastcentral New Mexico ( Dobrovolny and Summerson, 

1946). On the basis of the similarity of the fossil assemblage and lithology, the rocks at North Lake are 

correlated with the Tucumcari shale. 

At the other exposure, which is 3 miles east of Eunice 

.in the S'V% sec. 29, T. 21 S., R. · 38 E., randomly 

oriented blocks of limestone 3 to 5 feet thick and as 

much n.s 20 feet long have been uncovered in a gravel 

pit (fig. 338.3) 0 

The limestone is thick bedded to massive and is white, 

light gray, or buff; at places it weathers yellowish 

brown; it is fossiliferous, compact, moderately hard, and 

chalky. Some layers that consist mostly of fossil 

fragments also contain sand. The bedding planes are 

wavy and a few are marked by sha.ly partings. The 

upper surfaces of these blocks are smoothed and 

rounded, as if by sediment-laden water, and at places 

the abraded areas extend down into cracks along joints. 

Fossils in the limestone are difficult to remove from 

the matrix. The fossils have not been identified, but 

several genera of pelecypods and one or two genera of 

gastropods have been observed. Some lenses consist 

largely of fragments apparently deriv1ed from small 

individuals of Gryphaea. 

Brand (1953, p. 28) described similar limestones at 

~1cl(enzies Lake ai1d Cedar Lake in eastern Gaines 

County, Tex., about 50 to 60 miles northeast of the 

Eunice locality, which he correlated with the Comanche 

Peak limestone of the Fredericksburg !~roup of Early 

Cretaceoits age on the basis of fossil evidence. The 

lithology of some of the units of the Comanche Peak at 

Cedar Lake is strikingly·similar to that of the limestone 

blocks in the gravel pit, which, therefore, are believed 

to be equivalent to the Comanche Peak. 

Poorly cemented sandstone and conglomerate are 

associated with the limestone blocks and are exposed in 

three other pits nearby. Some of these rocks possibly 

are of Cretaceous age also, but they are lbarren of fossils 

and are similar to the Ogallala formation of Pliocene 

age, which underlies much of the surrounding area. 

Stratigraphic relations are obscure; at some places 

the limestone blocks rest directly on the Chinle formation of Late Triassic age, but many of the blocks are 

covered, and apparently are. ·underlain, by sand and 

gravel. 

Figure 338.3 shows most of the evidence bearing on 

the origin of the residual blocks, and indicates that the 

blocks probably were preserved from pre-Ogallala 

erosion in a collapse or subsidence depression in the 

red-beds surface. However, the blocks could have 

slumped into a narrow pre-Ogallala valley cut through 

the Cretaceous rocks and into the Triassic rocks. The 

alluvium-filled fissure near the right side of figure 338.3 
D-140 

0 

EXPLANATION 

+ 

Cretaceous exposure 

Areas of continuous subsurface occurrence 

Areas of discontinuous subsurface occurrence 

~4tooContour 

Drawn on top of the Cretaceous. Contour 

interval 50/eet; datum is sea level 

5 10 15 

;------------1 

i i 

I Albuquerque 

I • I NEW MEXICO 

I 

' LEA COUNTY~ 

L

l ,----r--------l.--....1 

-.J 

GEOLOGICAL SURVEY RESEARCH 1 9 61 

103 ° 30' 

,-

1 

I 

I 

I 

I 

20 MILES 

I 

I 

I 

I 

I 

jt~~"'l · . .:(. 

jjjj.: 

.. I 

I 

.:·.:r3700 

• ;,\,,;101>··· 

33°00'~--------------------~----------------~--------------------~ 

FIGURE 338.1.-Distribution of Cretaceous rocks in Lea County, N. Mex., based on 8,000 logs of water-wells and seismic 

shotholes provided by the State Engineer Office, and by oil and geophysical exploration companies. 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-4a5 D-141 

Slabby sandy limestone 

Nodular silty limestone 

b-"·-"j ···-···-· 

Siltstone 

Sandy siltstone 

Conglomerate 

Carbonaceous 

Bentonitic 

-f 

Fossiliferous 

FEET 

0 

3 

6 

9 

12 

15 

18 

.l!'rou1m 338.2.-Composite stmtigrnphic section of rocks exposed 

on the west side of North Lake, sec. 3, T. 1l S., R. 34 E. 

suggests that slumping or collapse also occurred after 

OgnJlala deposition which strengthens the collapsedepression hypothesis. 

SUBSURFACE OCCURRENCE 

The principal criteria for determining the distribution of Cretaceous rocks in the subsurface (fig. 338.1) 

consist of references in drillers' logs to 5 feet or more of 

"yellow," "blue," or "gray" cla.y or shale, which are not 

descriptive of other units in the n,rea. In some places 

descriptions of geologists' samples a1id the occurrence of 

fossils in drill cuttings have strengthened the interpretations. Some of the drillers' logs list limestone or 

sandstone with the clay or shale. :Many logs indicate 

gravel or coarse sand between the recognizable Cretaceous rocks and the Triassic rocks. Except for the sand 

a,nd gravel, t·he drillers' logs are consistent with the 

description of rocks at North Lake; therefore, the subsurface rocks are assigned tentatively to the Tucumcari shale. Although the sand and gravel may represent Trinity or lower Fredericksburg rocks, they are 

assigned tentatively to the Tucumcari shale. 

The main body of the Tucumcari shale lies unconformably on the eastward dipping red shales of the 

Chinle formation of Late Triassic age. It is nearly 

horizontal, and is overlain unconformably by the 

Ogallala formation and by sand, soil, and alluvium of 

Quaternary age. The erosional unconformity at the 

base of the Ogallala clips eastward at about 10 feet per 

mile, which is a little less than the slope of the land 

surface. 

There are two large depressions in the surface of the 

main body of the Tucumcari shale north of Tatum, the 

southernmost of which is beneath the land surface depression that contains Ranger Lake. The closed 

depressions in the top of the Tucumcari suggest subsidence after deposition. 

The main body of the Tucumcari shale ranges in 

thickness from 0 to nearly 200 feet but generally ranges 

between 50 and 100 feet. It is thickest in the northeastern part of the county and thins gradually to the 

west, pinching out a.long an irregular line from T. 9 S., 

R. 33 E. toT. 14 S., R.. 38 E. Incomplete data suggest 

that the Tucumcari shale thickens beneath the depressions. The four small areas of subsurface occurrence 

of Tucumcari shale west and south of the main body 

(fig. 338.1) a.re relatively thin, ra.nging in thickness 

from 0 to 50 feet and averaging about ~~0 feet. 

South of the areas in which the Tucumcari shale can 

be mapped as a continuous deposit are several areas of 

------Water ----- ----:::::- -

~ ~ § [3 D 

Limestone Limestone and Sandstone and Caliche Pebbly silt Red 

-

shale 

sandstone rubble conglomerate 

FIGURE 338.3.-Sketch of the rocks exposed in the north wall 

of a grnvel pit in the SW% sec. 2S), T. 21 8., R. 38 I~ .• east of 

Eunice, N. l\:lex. The red shale is the Ul1{1er Triassic Chinle 

formation; the limestone is the Cretaceous Comanche Peale 

limestone; the sandstone, conglomerate, and caliche nre 

probably the Pliocene Ogallala formation; nnd the pebbly silt 

and soil are of Pleistocene or Recent age. From photograph 

by Alfred Clebsch, ,Jr. 
D-142 GEOLOGICAL SURVEY RESEARCH 19 61 

discontinuous or sporadic occurrence of Cretaceous 

rocks. The thicknesses reported range from about 5 

feet to a little more than 100 feet. The average thickness in the large areas near Lovington and Hobbs is 

between 20 and 60 feet. Most of these areas contain 

shotholes for which the drillers did not note the diagnostic colors and rock types. However, this may reflect 

only the ·wide range in accuracy and quality of the 

drillers' logs. Cretaceous rocks may actually be somewhat more \videspread in the subsurface than shown 

on figure 338.1, judging by the logs of isolated wells 

and shotholes, but the data are too scarce to outline 

additional areas. 

In the ·southernmost subsurface outlier as shown on 

figure 338.1 and in a few wells 2 to 5 miles north of 

Hobbs, drillers have reported 5 to 20 feet of hard limestone or "hard gray rock", which might be the equivalent of the limestone exposed east of Eunice. 

· REFERENCES 

Brand, J. P., 1953, Cretaceous of Llano Estacado of Texas: 

Texas Univ. Bur. of Econ. Geology Rept. Inv., 20, 55 p. 

Conover, C. S., and Akin, P. D., 1942, Progress report on the 

ground-water supply of northern Lea County, New Mexico: 

New Mexico State Engineer 14th and 15th Bienn. Repts., 

1938-42, p. 285-309. 

Dane, C. H., and Bachman, G. 0., 1958, Preliminary geologic 

map of the southeastern part of New Mexico: U.S. Geol. 

Survey Misc. Geol. Ip.v. Map 1-256. 

Dobrovolny, Ernest, and Summerson, C. H., 1946, Geology of 

northwestern Quay County, New Mexico: U.S. Geol. Survey Oil and Gas Inv. Prelim. Map 62. 

Lang, W. B., 1947, Occurrence of Comanche rocks in Black 

River Valley, New Mexico: Am. Assoc. Petroleum Geologists Bull., v. 31, no. 8, p. 1472-1478. 

Theis, C. V., 1934, Progress report on the ground-water supply 

of Lea County, New Mexico: New Mexico State Engineer 

11th Bienn. Rept., 1932-34, p. 127-153. 

--.- 1938, Progress report on the ground-water supply of Lea 

County, New Mexico: New Mexico State Engineer 12th and 

13th Bienn. Repts., 1934-38, p. 121-134. 

339. DISTRIBUTION OF MOISTURE IN SOIL AND NEAR-SURFACE TUFF ON THE PAJARITO PLATEAU, LOS 

ALAMOS COUNTY, NEW MEXICO 

By JoHN H. ABRAHAMS, ,JR., JAMES E. WEIR, JR., and WILLIAM D. PURTYMUN, Albuquerque, N. Mex. 

TVork done in cooperation with the U.S. Atomic Energy Oom'mission 

The Pajarito Plateau adjoins the steep eastern flanks 

of the Sierra de los Valles in north-central New Mexico. 

It has been dissected by eastward-flowing streams into 

several fingerlike mesas. The plateau is underlain by 

pumice deposits, ash falls, ~nd ash flows that were 

ejected from a large volcanic vent to the west. Ash 

flows that cap the plateau are welded rhyolite tuff. Soil 

on the middle part of the mesas is well developed on 

the flat uplands and is thought to be derived largely 

from tuff weathered in place. Three zones are recognizable: An A zone from which most of the clay has 

been leached, a B zone containing montmorillonite, and 

a C zone (transitional from soil to tuff) with a high 

clay content. The zone of saturation is more than 1,000 

feet beneath the surface of the plateau in the areas 

studied (fig. 339.1). 

Measurements of the rate and amount of water movement and of moisture content of the soil and tuff, both 

under natural conditions and in controlled infiltration 

experiments, were made as an essential part of studies 

106"20' 

FIGURE 339.1.-Pajarito Plateau, N. Mex., showing area of 

moisture studies (shaded). 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-143 

of aqueous movements of radioactive substances originating from liquid wastes or from leachable radioactive 

solids. These measurements were made as a part of the 

program with the Los Alamos Scientific Laboratory. 

A neutron-scattering moisture probe was inserted 

into test holes cased with 2-inch plastic pipe to determine the moisture content of the rock and soil. The 

measurements were checked against laboratory determinations of moisture drill in cores. The moisture contents determined with the probe appeared to be about 

1 to 2 percent higher than those made in the laboratory. 

NATURAL DISTRIBUTION OF MOISTURE 

Twenty-three test holes were drilled on Frijoles Mesa 

and moisture measurements were made in the spring, 

summer, and fall of 1960 to study natural infiltration 

in the soil and tuff. In general, the moisture content 

was found to increase from the surface to a depth of 

2 to 3 feet, then decrease to a depth of 4 to 12 feet, 

nnd remain relatively constant at greater depths. 

There were some variations, however, that were apparently related to drainage and soil thickness. Data 

from the 23 test .holes are summarized in the adjacent 

table. 

Depth at which Depth at which 

Thickness of soil moisture content moisture content (feet) was less than 10 was less than 5 percent (feet) percent (feet) 

Range Average Range Average Range Average 

---------- ------

Fifteen test holes 

in well-drained 

areas __ --------- o. 5-4.0 3. 5 2. 5-9.0 4. 7 7. Q-14. 0 8.8 

Eight test holes 

near arroyos, 

ditches, and in 

poorly drained 

areas.---------- 2. 2-9.0 5. 3 4. 0-19.0+ 9. 5 (1) ----------

' Moisture content does not decrease to 5 percent; the hole-; range in depth from 19 

to 49 feet. 

The moisture content in the upper 5 or 6 feet was 

highest in March and April, as a result of late winter 

snow; it decreased to a minimum in October, owing to 

the high evapotranspiration rate during the summer 

and early fall. 

Test-hole 5M-2 (fig. 339.2) is representative of the 

test holes in well-drained areas. Moisture measurements show that below a depth of 6 feet the moisture 

0 5 10 15 20 25 30 35 40 45 50 

MOISTURE CONTENT, IN PERCENT BY VOLUME 

/ 0 5 10 15 20 25 30 35 40 45 50 0 5 10 15 20 25 30 35 40 45 50 

.... 

LIJ 

LIJ 

u.. 

.5 

15 

10 

15 

Test hole 5M-2 19 Test hole 6M-1 

20 

49 rJ d 

Test hole 1M-3A 

FIGURE 339.2.-Moistul'e measurements in selected test-holes on Frijoles Mesa,. Los Alamos County, N. Mex. 
D-144 GEOLOGICAL SURVEY RESEARCH 1 9 6 1 

content of the tuff remained unchanged and below 10 

feet it was less than 4 percent. 

Test holes near arroyos, ditches, and in poorly 

drained areas that received or retained water during 

periods of storm runoff are represented by test-holes 

6M-1 and 1~1-3A (fig. 339.2). Although moisture 

measurements in test-hole 6~1-1 suggest a small increase 

in moisture content between about 6 and 10 feet in 

depth between March and October, they merely ref:l.ect 

the fact that measurements in this interval were made 

at slightly different depths. Thus, additional points 

on the October curve probably would have resulted in 

a curve that more nearly duplicated the March curve. 

In hole 6M -1 the moisture content below a depth of 

about 4 feet rel11ained nearly the same, and the moisture 

content in the tnff ranged fron1 6 to 10 percent during 

both periods. 

Construction near test-hole 1M-3A, on the bank of 

an arroyo, caused water to pond 2 to 4 inches deep 

several feet from the test-hole during wet periods. The 

ponded water percolated through the thin soil and sand 

in the bed of the arroyo and moved downward and 

laterally into the tuff as shown by the increase of 

moisture from 12 percent to 17 percent at a depth of 

MOISTURE CONTENT, IN PERCENT BY VOLUME 

0 10 

2 

4 

.._ 

UJ 

UJ 

u.. 

z 

::i 

.._ 

a. 

UJ 6 

0 

8 

10 

20 30 40 0 10 20 30 40 

--------

No change 

below 6 feet 

0-14 days 

0-+-....................... ........_.~......~.-~~-'--1-.....L. ............ I....I.. ............ I....I..-'--1 

2 

4 

6 

8 

10 

After 

8 months 

drainage, 

Sept 2, 1960 

14-99 days 

0 

2 

4 

6 

8 

10 

20 

Total Q) porosity c: 

0 51.3 percent - N 

<( at a depth 

of 1 foot 

-

~ 

Total Q) porosity c: 

0 

N 46.9 percent 

m at a depth 

- of 2V2 feet 

- Q) 

c: 

0 

N 

(.) 

-- -- -----

Weathered tuff 

-

-

::: Unweathered tuff - :J 

.._ 

-

J11 

FIGURE 339.3.-Changes in moisture content beneath the infiltration pit at site A during 99 days of continuous infiltration, 

September 21 through December 29, 1959, and subsequent drainage for 8 months, Los Alamos County, X. l\Iex. Estimated rates of infiltration: 2nd day, 24 gallons per day per square foot; lOth day, 10 gpd per ft ~; 20th day, 6 

gpd per ft 2

• 

J 
,_ 

l 

SHOHT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-145 

6 t·o 1B feet (fig. 839.2). Between 13 and 20 feet a 

srna l1 increase in moisture content is suggested, but 

between 20 nncl 49 feet the moisture content remained 

about 6 to 8 percent. 

INFILTRATION EXPERIMENT 

At site A (f-ig. 389.1) an infiltration pit 2 feet in 

diameter by 1 foot deep "·as constructed during September 1056. The soil is similar to that on Frijoles 

:\[esn; it is about () feet thick a,nd is underlain by 

welded t:t;fr. T'he area is moderately well drained. A 

test·-hole 20 feet deep was ch·illed in the center of the 

infiltration pit nnd a 2-inch plastic pipe was installed 

so that. it projected about 1 foot above the pit. Soil 

and t"ldf were pncked around the casing to prevent 

seepage down alongside the casing. M:oisture measurernents were made prior to application of water. '\Tater 

was introduced into the pit and a constant head mainhtined at three-quarters of a foot for 99 days. 

The wetted front (fig. 339.3) moved to a depth of 

1tbout 4112 feet during the first 2 dn.ys of infiltration and 

t·o 1t depth of about 61j2 feet during the next 97 days, 

but water did not move through the transition zone 

int·o the tu.ff, except in the lower moisture range. The 

moisture content decreased with depth from a maximum of n.bout 38 percent in the B zone of the soil to 

less than 4 percent within a foot of the surface of the 

tuff. 

"ra.t-er apparently was perched on the C zone of the 

soil nncl the moisture content within the B zone approached saturation. After the first several days of 

infiltration, most mo,·ement of \Yater probably was 

lateral, as indicated by measurements in a series of 

holes around another infiltration pit nearby. Some 

water undoubtedly was lost by evaporation and transpiration. 

Although the qu:u~tity of water used during the study 

was equivalent to almost. :"50 years of precipit-ation on 

the Pajarito Plateau, the moisture content :in the A 

and B zones had returned to nea.rly norma] after 8 

months of drainage; the moisture content in the C zone 

and top 2 feet of tuff was slightly higher than before 

the experiment,· and the moisture content of the tuff 

between 8 and 20 feet wa.s unchanged. However, conditions during this study cannot be consider-ed normal 

because the clogging or silting of pores probably was 

greatly accelerated when this volume of water moved 

into the soil within a. period of 99 days without the 

normal seasonal distribution which involves alternate 

percolation and drainage. 

CONCLUSIONS 

Although \Yater not removed by surface drainage 

infiltrates into the soil of the Pajarito Platerw, this 

study indicates that the downward movement of this 

water is impeded or stopped by the dense. transition 

zm'le behYeen the soil and the tuff. Thus, it seems that 

where the normal soil cover is undisturbed, there would 

be little or no recharge to the zone of saturation from 

precipitation on the surface of the plateau. 

340. STRUCTURAL EVOLUTION OF THE VALLES CALDERA, NEW MEXICO, AND ITS BEAHING ON THE 

EMPLACEMENT OF RING DIKES \ 

By R. L. Sl\fl'l'H, R. A. BAILEY, and C. S. Ross, 'Vashington, D.C. 

The Valles caldera. is located 50 miles northwest of 

Santa Fe, N. J\1ex., in the heart of the Jemez J\1ountains, 

n. broad uplift composed of late Tertiary and Quaternary volcanic rocks that rest on igneous, metamorphic, 

and sedimentary rocks of Preca.mbrian throl.1gh Tertiary age. The volca.nic rocks are of the alkali-calcic 

suite and range in composition fron1. basalt, through 

andesite, dacite, rhyodacite, and quartz latite, to rhyolite. l'hey cover an area of over 1,000 square miles and 

attain a mnximum thicknes of at least 5,000 feet. Structurally, the volcanic rocks are situated on the western 

mn.rgin of the Rio Grande depression and are faulted 

progressively down\Yard to the east by numerous. northtrending faults. 

In early Pleistocene time, after a period of quiescence 

and erosion, a. series of catastrophic eruptions broke-out 

in the center of the volcanic pile, a.nd nearly 50 cubic 

miles of rhyolitic pyroclastic material in the form of ash 

flows poured, from vents now concealed, down canyons 

in the higher mountains and spread out as broad coalesced fans on the surrounding gentler slopes. The resulting deposits, now recognizable as sheets of welded 

tuff, attain a maximum thickness of 1,000 feet and constitute the larger part of the Bandelier rhyolite tuff 
D-146 GEOLOGICAL SURVEY RESEARCH 1 9 6 1 

(Smith, 1938). As a result of this tremendous outburst, the roof of the eviscerated magma chamber collapsed to form the Valles caldera (see Williams, 1941, 

p. 251-252). 

Subsequent activity-the main concern of the present 

paper-was confined within the caldera. It included in 

succession (a) eruption of rhyolite flows and pyroclastics on the caldera floor; (b) arching of the caldera 

floor. into a central structural dome; and (c) extrusion 

of a ring of volcanic domes peripheral to the structural 

dome. 

STRUCTURAL FEATURES 

The spatial relations of the intra-caldera units are 

shown on figure 340.1. The topographic rim of the caldera, slightly enlarged by erosion, is 12 to 15 miles in 

diameter. The ring faults bounding the subsided caldera block are la.rgely covered by younger volcanics and 

alluvium, but existing exposures indicate that they constitute a complex fracture zone 2 to 3 miles wide. Inside this ring-fracture zone is a central, initially a fairly 

intact block, which now is arched into a steep-sided 

structural dome that is bisected by a northeast-trending 

graben and broken by numerous .radial faults. The 

dome is a mosaic of blocks dipping radially as much as 

25°, is 8 miles in diameter, and has 3,000 feet of structural and topographic relief. That this structural dome 

was produced by positive vertical uplift, not differential 

collapse, can be proved by abundant evidence, most important of which are: (a) tilted lake beds and alluvium 

initially deposited on the caldera floor are now exposed 

on the dome at elevations' higher than the caldera rim; 

(b) prevolcanic sediments crop out 1,000 feet higher 

in the dome than in the caldera walls ; (c) Band~lier 

rhyolite tuff (Smith, 1938) on the crest of the dome 

crops out 1,200 to 2,000 feet higher than remnants of 

tuff in the fault-beheaded valleys on the rim; and (d) 

Redondo Peak, the highest point on the dome, is 1,000 to 

2,000 feet higher than peaks on the rim, yet is situated 

closest to the lowest segment of the rim. 

Moreover, the structural pattern of the dome itself 

strongly supports an origin by means of vertical uplift. This pattern is a variant of one that has been 

mapped many times (Wisser, 1960) and has been reproduced in clay-cake experiments by H. Cloos (1939) 

and others. It is considered compatible only with 

vertical forces, which cause radial and tangential tension over the surface of a dome owing· to increase of 

its area. The floor of the Valles caldera was without 

doubt domed by such forces, either in response to 

hydrostatic readjustment in the partly emptied magma 

chamber (an explanation suggested by van Bemmelen 

(1939, p. 138) for similar features in the Toba depression) or owing to a resurgence of new magma from 

below which resulted In the intrusion of a stock or 

laccolith. 

POST-SUBSIDENCE VULCANISM 

The eruptive events associated with the formation 

of the Valles structural dome are depicted in figure 

340.2. Following catastrophic eruption of the Bandelier rhyolite tuff (fig. 340.2A) and formation of the 

caldera by collapse, a group of early rhyolite lavas 

erupted along a northeast-trending zone on the caldera. 

floor (fig. 340.2B). Shortly thereafter the center of 

the caldera floor began to rise, and simultaneously a 

group of middle rhyolite lavas erupted from the ringfracture zone northwest of the dome. and also from 

within the graben forming along the crest of the dome 

(fig. 340.2C). The middle rhyolite northwest of the 

dome was interbedded with sediments (caldera fill) and 

tilted (fig. 340.1), whereas that in the graben was confined by faults and deformed as the graben deepened. 

Finally (fig. 340.2D), great volumes of viscous rhyolite 

erupted from the ring-fracture zone forming an almost 

complete ring of late rhyolite domes, many of which 

exceed 2 miles in diameter and rise 1,000 feet above the 

caldera floor. 

The foregoing post-subsidence history, with minor 

modifications, appears to be common to a number of 

calderas, particularly those associated with large. 

volumes of silicic welded tuffs. Van Bemmelen ( 1!.>29, 

1939) has described a similar sequence of structural 

doming and vulcanism in the Toba depression in northern Sumatra. The Rigis block, in the Gedongsoerian 

depression in southern Sumatra, also described by va,n 

Bemmelen (1932, 1935), has had a comparable history. 

In the San Juan Mountains, Colo., Steven and Ratte 

(1959) have recognized a structural dome within the 

Creede caldera, and Burbank and Luedke (Burbank, 

1933; Burbank and Luedke, oral communication, 1960) 

have found evidence for a similar structure in the 

Silverton caldera. Cornwall and Kleinhampl ( 1960) 

postulate structural doming within a Tertiary caldera 

near Beatty, Nev. Of considerable. importance also is 

the fact that B. C. King ( 1955) recognizes doming of 

the caldera floor in the Arran complex of Scotland. 

IGNEOUS RING COMPLEXES 

Granting that at least some igneous ring complexes 

are the subvolcanic equivalents of calderas as initially 

suggested by Clough, Maufe, and Bailey ( 1909) , and 

that they are but members of a denudation series 

(Reynolds, 1956, Buddington, 1959) , the central structural dome of the Valles caldera and its peripheral ring 

of volcanic domes may reasonably be considered the 

surficial equivalents of a central intrusion and an associated ring dike. Moreover, the close association in 

.J 
L 

L 

1.. 

SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293--435 

106°401 

36°00'r7~~~~~~~~~~~~~ 

551 

50' 

0 

Alluvium Early rhyolite 

Late rhyolite Bandelier rhyolite ~ tuff (Smith, 1938) 

Middle 

-

rhyolite 

LIEd 

Caldera fill 

Tertiary 

-

volcanics 

-~ 

~ 

Pre-Tertiary rocks 

~----,.,.,. 

Topographic rim of caldera 

------ Approximate position of 

ring-fracture zone 

Normal fault 

Dotted where concealed 

0 

......,...-

Contact 

~ 

General strike and dip 

of fault blocks 

0 

Late rhyolite 

e:ruptive center 

4 MILES 

~----~------~------~·~ 

FIGURE 340.1.--Generalized geologic map of the Valles caldera, Jemez Mountains, N. l\fex. 

D-147 
D-148 

pT 

D 

pT 

pT 

B 

NW 

pT 

A 

GEOLOGICAL SURVEY RESEARCH 19 61 

X X X X X X X X 

X X X X X X X X X X X X X X X 

X X X X X X X X X X X X X ~ X X X X 

X X X. X X X X X X 

X X X X X X X 

X X X X X X ~ X X 

X X X X X 

X X 

X X X X X X X 

X X X X I( X X X X X X X 

X X X X X X X X X X X X X X X 

X X X X X X X X X X X X X X X X 

/ I x~........ // I I x x x x x..........._ lloturn / I "'- x x x x x x? ,._ e f erupted _ ~x X X>< X X X X X;~--Q- magma ____ --x-,r'x-x X X X 

x x x x x x x x x "' x x x A :-x G ;---~-;;--->< A x x x x x x x x x x 

0 3 4MILES 

pT 

pT 

pT 

pT 

FIGURE 340.2.-Schematic sections showing the evolution of the Valles caldera (no vertical exaggeration). Patterns and 

:-::nuhol:-: are the same as for figure 340.1 Caldera fill omitted for simplicity·. 

j 

J 

J 
l 

SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-~~35 D-149 

time and space of structural doming and peripheral 

extrusion suggests that some ring dikes may be emplaced during uplift rather than during subsidence of 

the caldera floor, space for the ring dike being provided 

for by te.nsional reopening of the caldera ring fracture 

accompa.nying doming rather than by ring fracture or 

major stoping of the caldera block. In figure 340.3 

the two contrasting mechanisms are compared schemaJica.lly. The uppe.r diagram, depicting the mechanism effective. at .the Glen Coe and ~1ull complexes in 

Scot-ln.nd, shows ca.u ldron subsidence and contemporaneous ring intrusion along shear fractures inclined 

a way from the center of the complex (Anderson, 1936). 

The lower dingram of the. Valles caldera shows ring 

int.J·usion, as in:l:erred from vu lca.n ism, occurring during 

postsubsidence doming of the caldera floor, space being 

provided by tensional reopening of the ring fracture. 

The inclination of the. ring fracture in the Valles 

caldera is not known, but it is inferred to· be vertical 

or to dip steeply inward. 

GLEN COE TYPE 

lf'IGURE 340.3.-Schemutic sections contrasting the GlenCoe and 

Valles type calderas. 

It cannot be refuted that ring-fracture stoping and 

major stoping are demonstrable mechanis1ns in many 

ring complexes, but it is suggested that some ring complexes, especially those with central intrusions, may 

have originated by the mechanism evident in the Valles 

caldera. A preliminary reexamination of the literature 

on ring complexes indicates that a number of complexes 

may be so interpreted. 

REFERENCES 

Anderson, E. l\f., 1936, The dynamit:s of the formation of cone 

sheets, ring dikes, and cauldron subsidences: Royal Soc. 

Edinburgh Proc., v. 56, p. 128-157. 

Bemmelen, R. ,V., van, 1929, The origin of Lake Toba (North 

Sumatra) ; Pacific Sci. Congr. 4th (Bandoeng) Proc., v. 2A, 

p. 115-124. 

---1932, De Undatietheorie: Natuurk. Tijdschr. Nedcrlandish-Indi~•, , .. 92, p. 201-203. 

--- 1935, Vulkanotektonische depressies op Sumatra: Nederlandsch Natur. Geseek. Cong. (Leiclen), hdl. 25e, p. 289-293. 

-- 1939, The volcano-tectonic origin of Lake Toba (North 

Sumatra) : De Ingenieur NederlandReh-Indie, v. 6, p. 

126--140. 

Buddington, A. F., 1959, Granite emplacement: with special refer-

. ence to North America : Geol. Soc. America Bull., v. 70, p. 

671-748. 

Burbank, ,V, S., 1933, Vein systems of the Arrastre Basin and 

regional geologie struet.ure in the Silverton and 'l'elluride 

quadrangles, Colorado: Colorado Sci. Soc. Proc., v. 13, p. 

135-214. 

Gloos, Hans, 1939, Hebung-Spaltung-Vullumismus: Geol. Rundschau, v. 30, p. 405-528. 

Clough, C. T., M:aufe, I-I. B., and Bailey, ID. B., 1909, The 

cauldron-subsidence of Glen Coe, and the associated igneous 

phenomena: Geol. Soc. London Quart .. J<?ur., v. 65, p. 

611-678. 

Cornwall, I-I. R. and Kleinhampl, F .. J., 1960, Structural features 

of the Beatty area, Nevada [abs.] : Geol. Soc. America Bull., 

v. 71, p. 1845-1846. 

King, B. C., 1955, The Ard Bheiun area of the central igneous 

complex of Arran: Geol. Soc. London Quart. Jour., v. 110, 

p. 323-355. 

Reynolds, D. L., 1956, Calderas and ring-complexes : Koninkl. 

Nederlandsch. Geol.-l\'lijnb, Geuootschap, v. 16, v. 355-398. 

Smith, H. T. U., 1938, Tertiary geology of the Abiquiu quadrangle, New Mexico: .Jour. Geology, v. 46, no. 7, p. 933-9H5. 

Steven, T. A., and Ratte, .J. C., 1959, Caldera subs1idence in the 

Creede area, San Juan Mountains, Colorado [abs.]: Geol. 

Soc. America Bull., v. 70, p. 1788-1789. 

Williams, I-Iowel, 1941, Calderas and their origin: Univ: California Publ., Dept. Geol. Sci. Bull., v. 25, no. 6, p. 239-346. 

Wisser, Edward, 1960, Relation of ore deposition to doming in 

the North American Cordillera: Geol. Soc. America M:em. 

77, 117 p. 
D-150 GEOLOGICAL SURVEY RESEARCH 19 61 

341. HYPOTHETICAL CIRCULATION OF GROUND WATER AROUND SALT SPRINGS IN WESTERN OKLAHOMA, 

TEXAS, AND KANSAS 

By PoRTER E. v\TARD and A. R. LEONARD, Norman, Okla. 

Worlc done ·in cooperation with the U.S. Pnblic Health Service 

Salt springs, seeps, salt plains, and marshes occur at 

several places in western Oklahoma and adjacent parts 

of Texas and l{ansas. The ground water emerging 

from these springs and seeps is highly mineralized. 

The chloride concentration of water from individual 

springs ranges from about 20,000 to 190,000 ppm (parts 

per million) . Spring flow is small but the total salt 

load contributed to the Arkansas and Red Rivers is 

estimated to be 15,000 tons per day. Shallow halite deposits are concluded to be the source of the salt dissolved 

in these springs. 

Frye and Schoff (1942) have suggested that ground 

water circulating to depths of 1,000 feet or more may 

move down fault planes in local collapse basins and 

then flow many miles laterally at depth to emerge 

ultimately as salt springs. Frye and Schoff ·did not 

describe in detail the ground-water circulation at the 

springs. Recent studies of other springs have indicated 

that some springs result from circulation of ground 

water in shallow relatively local hydraulic systems 

(fig. 341.1). 

The salt springs occur in the outcrop area of red 

beds of Permian age, which consist principally of red 

and gray gypsiferous shale, siltstone, sandstone, massive 

gypsum, and thin dolomite. In the subsurface many 

of the beds contain halite as isolated crystals, discontinuous shaly lenses, and thick beds. Many of the springs 

FEET I P••ri•••T j 

0 

20 Fresh spring 

(intermittent) 

40 

Flowerpot shale 

60 

\ (low ''"""21 Salt spring 

(perennial) 

80 / - 100 :2ZZZZS?' 

/ 

120 

'--

0 2 MILES 

FIGURE 341.1.-Hypothetical circulation of ground water through 

halite-bearing Pennian rocks near a salt spring. Arrows 

show the direction of water movement. 

in Oklahoma emerge from shale or dolomite beds in 

the upper part of the Flowerpot shale (or its stratigraphic equivalent), less than 50 feet below the base 

of the Blaine gypsum. 'Box .canyons, prominent bluffs, 

and canyons are characteristic topographic features 

in most of the spring areas. The Permian red beds are 

relatively impermeable, but solution channels are well 

developed and common in the gypsum and dolomite 

beds. The shale and siltstone beds are fractured, 

jointed, and contain numerous small veins of selenite 

that have been deposited in the joint·s and along bedding 

planes by circulating ground water. 

Salt hoppers or molds of salt crystals are common 

in the shale in the upper part of the Flowerpot shale, 

and halite has b~en found at depths of less than 100 

feet in core holes drilled near some of the springs and 

plains. A core hole drilled about 1 mile from one of 

the salt springs in southwestern Oklahoma indicated 

that ground water had circulated through nearby haliterich deposits. At a depth of 200 feet the hole penetrated shale containing cubic voids which were formerly 

occupied by halite crystals. A few inches deeper the 

voids were partly filled "·ith halite, and at still greater 

depth the halite cubes were unaffected by the so1vent 

action of ground water. 

Although halite occurrences are widespread, the 

springs occur at relatively few places, suggesting that 

certain conditions are necessary for a salt spring: (a) 

halite deposits or halite-bearing rocks at shallow depth; 

(b) ground water that circulates to the halite-bearing 

zones; and (c) a local topographically low area where 

the water can emerge as a mineral spring. Joints and 

fractures in the shale apparently do not extend to 

depths of more than a few hundred feet, and most of the 

halite at such depths in western Oklahoma, Texas, and 

l{ansas seems to be beyond the reach of circulating 

ground water. In areas o£ flat topography, small 

amounts of water may reach and dissolve the salt, 

but are not able to circulate to a lower point of 

emergence because of the topography. This salt water 

probably moves laterally into other formations in the 

subsurface. Conditions such as this occur southwest 

of Wichita, Kans., where brine for a chemical plant 

is pumped from wells about 600 feet deep although no 

salt springs are known in the area. The brine occurs 

in the Wellington formation of Permian age in a zone 

J 
SHORT PAPERS IN THE GEOLOGIC A}fD HYDROLOGIC ·SCIENC.ES, ARTICLES 293-435 1)-151 

that contains haJite deposits a few miles to the west 

(fig. 341.2.). 

Further evidence for the shallow circulation of 

ground water around the salt spring~ is the occurrence 

FEET 

0 

500 

1000 

0 

Surface depressions 

/ \ 

Slumping caused by salt removal 

------Sait water 

5 10 MILES 

lfJGUim 341.2.-Genernlized (•ross sedion in south-central Kansas showing the removal of salt from the Wellington formation 

(Permian) through solution by ground water. Arrows indicate direction of ground-water movement. 

of sinkholes and surface collapse features along the eastern limit of the salt deposits andl in the vicinity of 

many salt springs. For example, the Great Salt Plain 

in Alfalfa County in northwestern Oklahoma is. a low 

subcircular shallow basin that was formed, at least in 

part, by collapse resulting from the remo·val of underlying salt deposits. Salt water seeps from the underlying broken bedrock into the alluvium covering the 

basin and thence into the Salt Fork of the Arkansas 

River. Salt is brought to the surface in this manner at 

a rate of more than 3,000 tons per d:a.y. 

Water collected from several spring areas in 195'$) has 

been shown by tritium analyses to contain a large proportion of post:-1954 water. Considering the low permeability, the rate that water moves through the rocks 

must be slow; consequently, the water could not have 

migrated more than a few miles in so short a time. 

REFERENCEE: 

Frye, J. C., and Schoff, S. L., 1942, Deep-seated solution in the 

Meade Basin and vicinity, Kansas and Oklahoma, in Symposium on relations of geology and the ground-water !Jl'C.1blems of the Southwest: Am. Geophys. Union Trans., 23d 

Ann. Mtg., pt. 1, p. 35-39. 

Lee, Wallace, 1949, Subsurface geologie cross section from Barber County to ~aline County, Kansas: Kansas Geol. Survey 

Oil and Gas Inv. no. R, 16 p. 

342. BRECCIA AT SIERRA MADERA, TEXAS 

By R. E. EGGLETON and E. M. SHOEMAKER, Menlo Park, Calif. 

Worl,; done in coopemtion with the National A.erona.utics and Space Administmt-ion 

Sierra l\{adera, Tex., is an isolated group of hills on 

the southern edge of the Edwards Plateau underlain 

by highly deformed Permian dolomite and limestone; 

the structure contrasts sharply with that of less-deformed Permian rocks in the surrounding region. IGng 

(1930), who first mapped the area in detail, interpreted 

the structure as a com.plex dome with overturned beds 

on the flanks, broken by radial faults, and partly encompassed by smaller concentric folds; he compared 

it with the similar but much larger Vredefort dome of 

South Africa. On the basis of IGng's interpretation, 

Boon n.nd Albritton (1937, p. 60-62) suggested the 

structure was formed by meteorite impa,ct. Data, obtained from drill holes and outcrop since 1937 show that 

the structure of Sierra Madera is even more unusual 

than IGng supposed and tend to support the suggestion 

of impact origin. 

In the fall of 1959 Sierra Madera was visited by 

Shoemaker, in company with R. S. Dietz, R.. J. I-Inckman, and A. C. Mason, who found that the Permian 

beds contained abundant conical slip surfaces termed 

shatter cones (Dietz, 1960). On this visit the centn11 

part of the structure was found by Shoe:rha.ker to be 

underlain by an immense mass of breccia, and the. 

northwestern boundary of: the br-eccia was located. The 

approximate extent of the breceia was determined by 

Shoemaker, Eggleton, and Roaeh on a second visit in 

January 1961 (fig. 342.1). Knowledge of the shape and 

character of this breccia mass, the existence of which 

has not been fully recognized heretofore, is critical to 

the interpretation of the origin of the structure. 

The breccia zone consists of blocks of carbonate rocks 

up to several hundred feet across. enclosed in a matrix of 

angular fragments that grade progressively downward 

in size to microbreccia. In the outcrops, about half of 

the breccia is composed of fragments small enough to 

permit recognition of the clastie nature of the material 

in hand specimens. Microbrecc:ia, recognizable in thin 
D-152 GEOLOGICAL SURVEY R~SEARCH 1 9 6 1 

Geology adapted from King (1930). Breccia mapped by 

E. M. Shoemaker, R. E. Eggleton, and C. H. Roach, 

1959 and 1961 

0 2 MILES. 

EXPLANATION 

>- Ct: 

H D 

Alluvium 0 

J 

uiCt:>-

:;:,00::: 

0 .<! • LIJ>- z: Breccia u~ffi 

Fragments of dowmite and limestcnuJ ;:: i= !;( 

ranging from microscopic size l:i:! ffi :::> 

to several hundred feet across u 1- 0 

Limestone and sandstone 

Dolomite and limestone 

}

'VI 

~6 Q:LIJ uu 

Contact Dashed where approximately lccated 

Fault 

Dotted where concealed 

,( 

/0 

Strike and· dip of beds 

.,f1(60 

Strike and dip of overturned beds 

"' 

Strike of vertical beds 

0 

1 

Drill hole 1. Thompson No. 1 E!Binore 

1l. Phillips No. 1 Elsinore 

3. Hunt No. 48 Elsinore 

FIGURE 342.1.-Geologic sketch map of Sierra Madera, Tex. 

section, constitutes a smaller proportion of the body 

and forms the matrix between the larger fragments. 

Some of the microbreccia consists of mixed fragments 

derived from beds of diverse lithology and some is composed entirely of fragments of uniform lithology. All 

gradations may be found between mixed microbre~cia 

and rock which has merely been shattered. 

Three deep holes have been drilled at Sierra Madera, 

two of which began in the breccia. Drill cuttings of the 

upper 3,100 feet of Phillips No. 1 Elsinore well, which 

is located near the center of the breccia, were kindly 

given to us by Mr. Addison Young and logged by 

Eggleton. We are also indebted to Mr. Young for correlation of units between the three wells. 

Three main lithologic phases are present in the cuttings of the Phillips No. 1 Elsinore hole: (a) mi~robreccia with light-colored matrix, (b) microbreccia 

with dark material in the matrix, and (c) unfractured 

dolomite and limestone. Dolomite is predominant over 

limestone. In most samples the cuttings are mainly 

chips about 1 to 5 mm long but some are as long as 1 em 

and rarely 2 em. The microbreccia is a prominent 

constituent of the cuttings from the surface to a depth 

of about 1,600 feet and again between depths of about 

2,600 feet and 2,800 feet. Microbreccia with dark 

material in the matrix is the predominant constituent of 

the cuttings between 800 feet and 1,170 feet and is rare 

in other sam pies. 

A typical specimen of micro breccia with light-colored 

matrix consists of angular fragments of moderate yellowish-brown to light brownish-gray, yellowish-gray, 

and pinkish--gray to white carbonate rocks in a very 

pale orange carbonate matrix (fig. 342.2A). It contains 

30 percent fragments ranging from 0.2 mm to 5 mm in 

length and about 70 percent matrix composed of grains 

finer than 0.2 1nm. The fragments have sharp corners 

and rough, commonly concave, faces. 

0 

I 

5 MILLIMETERS 

I 

FIGURE 342.2.-Chips of breccia from cuttings from Phillips 

Petroleum Company's drill hole No. 1 Elsinore. A, Breccia 

with light-colored matrix; B, Breccia with dark material in 

the matrix: Rock fragments, stippled; light-colored matrix, 

·white; dark material in matrix, blacl~; and pyrite, densely ruled. 

..l 
'• 

SHOH.T PAPERS IN THE GEOLOGIC AND HYDROL.OGIC SCIENCES, ARTICLES 293-435 D-153 

Typical microbreccia with dark material in the matrix has angular fragments of very light gray and light 

yellowish-brown carbonate rock in light brownish-gray 

matrix. The dark material, which is black megascopically. but brown and slightly translucent as seen with 

the microscope, occurs both as partial films on the angular frn.gments of carbonate rock n.nd as very small 

particles generally less than 1 mm long. Some of the 

films of dark material can be recognized to be stylolites 

but others cannot be so identified (fig. 342.2B). 

The composition of the dark material in the matrix 

of the microbreccia has not been determined but most 

of it is evidently carbonaceous. .Pyrite constitutes 

about 0.001 percent of the n1aterial in the cuttings. No 

meteoritic constituent has yet been identified. 

Structures· observed in the cuttings include slickensides and segments of shatter cones. T~e slickensides 

appear to be most common in the samples having abundant microbreccia. Shatter cones are conical surfaces 

in the carbonate rocks marked with fine straight ridges 

and grooves radiating from the apices of the cones or 

from subsidiary flanking conelets. The shatter cones 

seen n.t. Sierra,. :Madera are typically about 2 em to 20 em 

in basal diameter and only small parts of their surfaces 

car~ be found in cuttings. Their distribution in the drill 

hole appears to be relatively uniform throughout the 

intervnJ studiecl. 

Young (1952), who at first identified the cuttings 

fr-om the upper part of the Phillips No. 1 Elsinore well 

as part of the Leonard series of Permian age, now (written communication, 1960) places the base of the Leonard 

at 4,100 feet. The 4,000+ foot thickness assigned to 

the Leonard contrasts sharply with a normal thickness 

for the Leonard of about 2,000 feet in the Glass Mountn.ins to the southwest and with 2,660 feet in the Hunt 

No. 48 Elsinore well (Young, written communication, 

1960) on the flank of the Sierra 1\iadera structure. The 

additional 1,440 feet assigned to the Leonard in the 

Phillips No. 1 Elsinore well can be attributed entirely 

to the breccia, which extends to a depth of at least 1,600 

feet and possible 2,800 feet. Structural relief on the 

top of an anhydrite bed, which occurs at 2,910 feet in 

the Phillips No. 1 Elsinore well, is only about 500 feet 

between the three wells drilled at Sierra :Madera. Dips 

of the beds a short distance beneath the breccia are, 

tlu~refore, probably fairly gentle. 

On the basis of the surface and subsurface information the breccia at Sierra Madera is here tentatively interpreted as a great lens, 11h miles across and possibly as 

much as 2,800 feet thick, nested in a collnr of steeply upturned and overturned beds. The strueture nppears to 

be similnr to. that at 1\ieteor Crater, Ariz., and at the 

Teapot Ess nuclear explosion crater at the Nevada Test 

Site of the U.S. Atomic Energy Commission (Shoemaker, 1960, p. 422-424). By analogy, the breccia at 

Sierra l\1adera may once have underlain a crater about 

2 miles in diameter. 

REFERENCES 

Boon, J.D., and Albritton, C. C., Jr., 1937, Meteorite scars in 

ancient rocks: 1J'ield and Laboratory, v. 15, no. 2, p. 53-64. 

Dietz, R. S., 1960, Meteorite impact suggested by shatter cones 

in rock: Science, v. 131, p. 17Sl-1784. 

King, P. B., 1930, The geology of the Glass Mountains, Texas; 

Part 1, Descriptive geology: Texas Uni.v. Bull. 3038, 167 p. 

Shoemaker, E. M:., 1960, Penetration mechanics of high velocity 

meteorites, illustrated by Meteor Crater, Arizona: Internat. 

Geol. Cong., 21st, Copenhagen 1960, Rept., pt. 18, p. 418-434. 

Young, Addison, 1952, Geologic section in Phillips Petroleum 

Company's Elsinore Cattle Company No. 1, in West Texas 

Geol. Soc. Guidebook, 1952 spring field trip, Marathon 

Basin, B1·ewster and Pec-os Counties, Trans-Pecos, Texn~: 

p. 72-73. 

343. JOHN DAY FORMATION NEAR ASHWOOD, NORTH-CENTRAL OREGON 

By DALLAS L. PEcK, Menlo Park, Calif. 

The thickness and lithology of the upper Oligocene 

and lower Miocene John Day formation change markedly between Ashwood, Oreg., and the type area al.ong 

the John Day River between Clarno and Picture Gorge, 

20 to 60 miles to the east (fig. 343.1). At the type 

area. the formation consists of 1,000 to 2,500 feet of 

richly fossiliferous varicolored andesitic to rhyolitic 

tuff and tuft'a~ous claystone that were mostly deposited 

60449R 0-131-11 

as ash falls (Merriam, 1901, p. 291--303; Calkins, 1902, 

p. 143-159; R. G. Coleman ;

1 Fisher and "\'Ti]cox, 1960, 

and Hay, R. L., 1961). West of the John Day River 

the formation contains increasingly abundant rhyolitic 

volcanic rocks ('\'Vaters, 1954). Between Ashwood 

and Willowdale it consists of aboUtt 4,000 feet. of tuff, 

1 R. G. Coleman, 1949, The John Day formntlon In th.!l Picture Gorge 

quadrangle, Oregon: Oregon State College Masters Thesis. 
D-154 GEOLOGICAL SURVEY RESEARCH 1 9 61 

121° us· 45"00'.....--------T----------------.45"00' 

Antelope 

2! Willowdale 

OREGON 

( 

f 

i 

Monument 

• 

«~ --------~======~~~==--=~=·~----------k 4~ 

0 40 MILES 

FIGURE 343.1.-Index map of part of north-central Oregon. X, 

location of ehemieally analyzed samples listed in table 343.1. 

lapilli tuff, strongly to weakly welded ash flows, and 

subordinate flows of trachyandesite and rhyolite (fig. 

343.2). The rhyolitic flows are related to a large 

rhyolitic dome in the lower part of the formation, exposed along Trout Creek northwest of Ashwood. 

The moderately to strongly welded ash flows range 

in thickness from 50 to 400 feet.. Some of the thicker 

units, however, may be composed of several separate 

ash flows that comprise a single cooling unit (as defined 

by Smith, 1960, p. 812). Each ash flow consists of hard 

\Yelded lithoidal rock, light gray to reddish, overlying 

a. thin layer of nonwelded tuff and gray vitric welded 

tuff in which welded vitroclastic texture is discernible 

with a hand lens. From a trace to 20 percent (by 

volume) of each ash flow is composed of intratelluric 

crystals and crystal fragments, mostly of anorthoclase, 

oligoclase, and quartz. Sparse to abundant lithophysae, mostly concentrated in layers, occur in the 

upper, lithoidal part of each ash flow. In the basal 

portion of one thin nonwelded to weakly welded ash 

flow are abundant chalcedony-filled spherulites ("thunder-eggs~'), described by Ross (1941). Chemica-l analyses of samples from three widespread ash flows are 

listed in table 343.1. The analyses show that the ash 

flows are rhyolitic, whereas analyzed silicic volcanic 

rocks in contemporaneous strata in the Oregon Cascade 

Range a.re dacitic and rhyodacitic (Peck, 1960a, 1960b). 

·The contrast in lithology of the John Day formation 

between Ashwood and the area along the John Day 

River is the result of at least two independent factors. 

The rhyolitic dome, lava flows, ash flows, and some of 

the tuff and lapilli tuff near Ashwood were derived 

from nearby vents. Eastward, a way from the vents, 

the lava flows and ash flows become thinner and less 

abundant, and they are almost completely missing along 

the John Day River. The deposits of rhyolitic tuff 

TABLE 343.1.-Chemical analyses, specific gravity,· and norms of 

ash flows in the John Day formation near Ashwood, northcentral Oregon 

lRapid rock analyses by P. L. D. Elmore, I. H. Barlow, and S. D. Botts; location 

of samples shown on map and stratigraphic position shown on columnar section] 

Chemical analysis (percent) 

Si02 __________________________ _ 

AbOa---- ~--------------------- Fe2

0 3 _________________________ _ 

FeO __________________________ _ 

~gO~-------------------------- CaO _________________________ ~_ 

N a20 _________________________ -

K 20 __________________________ _ 

H2o __________________________ _ Ti02 

__________________________ ~ 

0s----------------~---------- ~n0 _________________________ _ 

C02 _________________ - ___ -- ____ -

71. 8 

13. 0 

1.3 

. 26 

. 12 

-87 

2. 3 

5. 0 

5. 4 

. 16 

. 01 

. 03 

. 05 

TotaL __________ :. ________ 100 

Specific gTavity (powder) 

2. 26 

Norms (weight J)E'rcent) 

Quartz _____________ - - - - _ -- - _·-- -

Orthoclase _____________________ -

Albite _________________________ _ 

Anorthite ____________ -- __ -- ____ - Corundum _____________________ _ 

Hypersthene enstatite ___________ _ ~agnetite _____________________ _ 

Hematite __________ ------------- Ilmenite _________________ -- ____ -

37 

30 

19 

4. 2 

2. 2 

.3 

.5 

1.0 

.3 

2 

73. 8 

11. 4 

1.7 

. 85 

. 10 

- 78 

2. 2 

4. 8 

4. 2 

. 18 

. 02 

. -05 

-05 

100 

2. 34 

41 

28 

18 

3. 9 

1.2 

.2 

2. 1 

.3 

.5 

Normative feldspar (moleculaT J)E'rcE'nt) 

Orthoclase___ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 54 55 

Albite__________________________ 38 

Anorthite_______________________ 8 3~ 

72. 2 

11. 4 

1.4 

. 66 

.·33 

. 61 

2. 9 

3. 4 

6. 0 

99 

. 16 

. 01 

. 08 

. 07 

2. 29 

41 

20 

25 

3. 1 

1.8 

.8 

1.9 

.2 

.3 

41 

53 

6 

1. Welded tuff (DLP-58-42); collected from vitric base of ash flow in sec. 12, T. 10 

S., R. 16 E., at 3,350 feet altitude on bank of county road 1.9 miles S. 62° W. of 

Ashwood. Yellowish-gray vitric rock containing 2 percent crystals and crystal 

fragments (avg. 1 mm in diameter) of sodic oligoclase in shards and ash of glass 

(N = 1.50), a small part of which is devitrified to tJ-cristobalite and feldspar. 

2. Welded tuff (DLP-58-50); collected from vitric base of ash flow in sec. 18, T. 

8 S., R. 17 E., on bank of county road 2.6 miles S. 25° W. of Antelope. Medium 

gray vitric rock containing about ~ or 1 percent crystals and crystal fragments 

of calcic oligoclase and a trace or altered pyroxene and amphibole in welded 

shards and ash of glass (N = 1.50) that is partially de vitrified to tJ-cristobalite 

and feldspar. · 

3. Welded tuff (DLP-58-39a); collected from vitric base of welded ash flow in sec. 

20, T. 9 S., R. 15 E., in roadcut on eastern side of former U.S. Highway 97, half 

a mile south of Pacific States Cut Stone quarry. Medium light gray rock 

containing a trace of crystals and crystal fragments of sodic plagioclase and 

quartz in welded shards IUld ash of pale brown glass (N=1.50) that is partially 

devitrified to tJ-cristobalite and feldspar. 

., 
.... 

... 

cu 

.2: 

a::~ 

ftl ftl 

:.c::: E.o 

:I 

8 

c: 

~ ftl 

E 

.E 

)\ 

ftl 

0 

c: 

r. 

0 

'"'\ 

c: 0.2 

c; ... ... ftl 

.!!! E U'-,E 

SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-155 

THICKNESS, 

IN FEET LITHOLOGY r--- Basaltic flows; columnar-jointed flows of very fine-grained dark-gray'basalt; a few smalllensf!S of tuff 

between some flows. 

450-600 

----- 150 

----

300 

-----

_s~~ 

100-400 

=3= 

300-900' 

=B 

100-400 

=~ 

0-400 

------

200-1500 

)-_.{ 

~ /--,-

(;;;/ 

~ ..(' 

Massive tuff and leas abundant pumice lapilli tuff; mostly yellowish-gray poorly sorted air··fall tuff. 

Vertebrate fo88ils of Miocene age found at several localities (Hodge, 1932, p. 697). Contains several percent crystals, mostly andesine, and fragments of hyalopilitic andesite. 

~ Massive lapilli tuff (ash,flow) overlain by 25 feet of thinly bedded waterlaid tuff; light-gray lapilli tuff 

contains angular )apilli of dark-gray obsidian and flattened pumice lapilli in a "salt and pepper" matrix; 

~ 

nonwelded except for weakly welded 25-foot layer at base. Contains less than 1 percent crystals, mostly 

oligoclase, and 1 to 2 percent fragments of andesite and schist. 

Massive tuff and pumice lapilli tuf.f; greenish-yellow and yellow-gray ash-flo'Y and air-fall tuff. 

~ Moderately welded rhyolitic ash flow; varicolored in shades of red, orange, and gray; porous-textured 

--+"-.:;..;;~.;-X 3 stony rock containing sparse lithophysae; shards visible in most hand specimens; thin vitric la3rer at base. 

--- Contains a trace of crystals, mostly oligoclase and quartz. 

Tuff and lapilli tuff; poorly exposed. 

Strongly welded crystal-rich rhyolitic ash flow; purplish-red to very pale orange stony rock containing 

moderately abundant lithophysae and 10 to 20 percent crystals as large as 2 mm. Crystals consist of 

anorthoclase (about Or30AbAn 70 ) and much less abundant oligoclase, quartz, and myrmekitic intergrowths 

of quartz and anorthoclase; crystals lie .. in a finely devitrified matrix derived from welded glass shards 

and ash. 

Tuff and lapilli · tuff; varicolored massive air-fall and ash-flow tuff and well-bedded wa.terlaid tuff. 

Contains sparse fragments of bones and silicified wood. 

_/ 

Weakly welded rhyolitic ash flow; light-gray rock speckled with abundant angular fragments of black 

glass. Lower 4 to 6 inches of ash flow is moderately welded; in many areas it is altered to clays and 

opal, and contains abundant chalcedony-filled spherulites ("thunder-eggs"). Contains about 1 percent 

crystals of calcic oligoclase and a trace of quartz and altered pyroxene; glass fragme:1ts consist of per-

---litic vitric welded tuff. 

Strongly welded rhyolitic ash flow; light-gray to pale-red stony rock; composed of dense platy layers 

that alternate with lithophysae-rich massive layers; thin vitric layer at base. Devitrified to fine-grained 

_j~$;~~~ stony aggregate composed of quartz, tridymite, alkalic feldspar, and iron oxide minerals, in which shard 

2 --- structure is rarely visible; contains only traces of intratelluric crystals, mostly of oligoclase . 

-;:::=:~==:a ---- Massive tuff and lapilli tuff; light-gray to yellow air-fall tuff. 

Local rhyolitic flows; light-gray to grayish-red massive and flow-banded rocks; typically contain about 

2 percent crystals as much as 2 mm long, which weather to give the rock a spotted appenrance. Thin 

----......... vitric ash flow occurs locally at base. Crystals con<~ist mostly of sodic plagioclase; lrroundmass Is 

~ devitrified. 

Trachyandesitic flows and minor tuff;flowscom~sed of very dark gray aphanitic rock that breaks into 

fist-size pieces upon weathering. Rock consists of felted laths of andesine and grains of clinopyroxene 

(ferriferous pigeonite) and magnetite in a glassy matrix. 

~ Strongly welded rhyolitic ash flow; light-gray stony rock containing moderately abundant lithophysae 

and 1 to 2 percent crystals; thin vitric layer at base. Crystals consist mostly of sodic oligoclase, which 

lie in a devitrified matrix. 

~ Tuff; poorly exposed. Fossil leaves of late Oligocene age found at one l~ality (J. E. Wolfe, 1959, 

~ written communication). 

_.,.-- s'trongly welded rhyolitic ash flow; light-gray stony rock containing sparse lithophysae and about 5 percent c~ys_tals; thin vitric layer at base.. Crystals consist of equally abundant quartz and feldspar, and 

--..........._ r~re b10t1te and hornblende; feldspar IS mostly anorthoclase (about Or40 AbAn 60 ) but includes calcic ............._ ohgoclase. 

Andesitic flows, breccia, and tuff; thin reddish saprolite at top of formation . 

ll'mum•: 343.2.-Generalized columnar section of the John Day formation between Ashwood and Willowdale, north-central 

Oregon. x and number shows stratigraphic positions of chemically analyzed samples listed in table 343.1. 
D-156 GEOLOGICAL SURVEY RESEARCH 1 9 61 

and lapilli tuff probably also thin eastward away from 

the vents. Some of the tuff, lapilli tuff, and tuffaceous 

claystone both near Ashwood and along the John Day 

River may have been derived from contemporaneous 

vents in an ancestral Cascade Range, 60 to 120 miles to 

the west ( R. G. Coleman; 2 R. L. Hay, written communication, 1961). Grain siz.e o'f the tuffaceous rocks 

decreases eastward from Ashwood to Picture Gorge, 

and the rocks are similar in composition to contemporaneous andesitic, dacitic, and rhyodacitic pyroclastic rocks, flows, and intrusives in the 'Vestern Cascades (Peck, 1960a, 1960b). A decrease in thickness 

of these tuffaceous rocks eastward a way from the vents 

probably accompanies the eastward decrease in grain 

size. 

REFERENCES 

Calkins, F. C., 1902, A contribution to the petrography of the 

John Day Basin [Oregon]: California Univ. Publ. Dept. 

Geol. Bull., v. 3, p. 109-172. 

2 See footnote 1. 

Fisher, R. V., and Wilcox, R. E., 1960, The John Day formation 

in the Monument quadrangle, Oregon, in Short papers in 

the geological sciences: U.S. Geol. Survey Prof. Paper 

400-B, p. B302-B304. 

Hay, R. L., 1961, Diagenetic facies in the John Day formation 

of Oregon : Geol. Soc. America Cordilleran Section Program, p. 41-42. 

Hodge, E. T., 1932, New evidence of the age of the John Day 

formation: Geol. Soc. America Bull., v. 43, p. 69;}--702. 

Merriam, J. C., 1901, A contribution to the geology of the John 

Day Basin [Oregon] : California Univ. Publ. Dept. Geol. 

Bull., v. 2, p. 269-314. 

Peck, D. L., 1960a, Geologic reconnaissance of the 'Vestern 

Cascades in Oregon north of latitude 43 degrees: U.S. Geol. 

Survey open-file report. 

--, 1960b, Cenozoic volcanism in the Oregon Cascades, in 

Short papers in the geological sciences: U.S. Geol. Survey 

Prof. Paper 400-B, p. B308-B310. 

Ross, C. S., 1941, Origin and geometric form of chalcedony-filled 

spherulites from Oregon: Am. Mineralogist, v. 26, p. 

727-732. 

Smith, R. L., 1960, Ash flows: Geol. Soc. America Bull., v. 71, 

p. 795-842. 

Waters, A. C., 1954, John Day formation west of its type locality [abs.] : Geol. Soc. America Bull., v. 65, p. 1320. 

344. DIFFERENTIATED GABBROIC SILLS AND ASSOCIATED ALKALIC ROCKS IN THE. CENTRAL PART OF 

THE OREGON COAST RANGE, OREGON 

By P. D. SNAVELY, JR., and H. C. WAGNER, Menlo Park, Calif. 

Gabbroic and alkalic hypabyssal intrusive bodies 1 

that are closely related in space and time of development crop out throughout the central part of the 

Oregon Coast Range (fig. 344.1). The distribution of 

these bodies ha.s been known for som.e time and the 

petrology of some of these intrusives has been briefly 

described by Rogers and others (1941), Baldwin 

(1947, 1956a, b), Snavely and Vokes (1949), and 

Snavely and others (1950) ; Roberts (1953) described 

in detail the petrology of the Marys Peak sill. 

Studies in progress on the ga.bbroic and alkalic rocks 

in the Oregon Coast Range are concerned prim.arily 

with their magmatic evolution. The origin of the alkalic rocks is of particular interest. Considerable 

field and chemical data, summarized here, are available 

and bear on the parentage of these rocks. 

FIELD RELATIONS 

The gabbroic and alkalic rocks occur generally as 

intrusive sheets that have angles of inclination ranging 

t The term 2nbbrotc, as used here, Includes Intrusive r.ocks that range 

In composition from gabbro to dilortte, and general'ly have granophyrlc, 

oph.ftlc, and subophttlc teJttures. !They are commonly referred to as 

dolerftes by wr.fters outside North America. Th~ alkalic rocks discussed Include nepheline sy~ntte and camptontte. 

from nearly flat-lying to vertical; the thicker bodies are 

essentially horizontal. As the angular discordance between the thicker intrusive· sheets and the enclosing 

strata is generally less than 20 degrees, the sheets are 

termed sills. The gabbroic sills commonly are thickest 

along the crest of the Coast Range uplift and thin toward the flanks. At most places the alkalic rocks crop 

out west of the gabbroic intrusives and, although in 

close proximity, the two types have not been found in 

contact. Intrusives of both rock types usually occur 

in beds of Eocene age and are not known to intrude 

strata younger than middle Oligocene. Gabbroic sills 

probably covered an area of more than 2,500 square 

miles; the.ir thickness averages 400 to 500 feet, but locally is more than 1,000 feet. Erosional remnants of 

sills cap most of the prominent flat-topped mountains 

and concordant upland surfaces such as Mount Hebo, 

Mount Gauldy, Saddleback Mountain, Fan no Peak, 

Euchre Mountain, Marys Peak, Prairie Peak, and 

Roman Nose Mountain. The alkalic rocks probably 

comprise less than 5 percent of the intrusive suite h~ 

the Oregon Coast Range. Nepheline syenite porphyry 

forms the stock at Blodgett Peak in the Waldport 

quadrangle and the 200- to 300-foot sills that cap Table 

and Cannibal l\fountains in the Tidewater quadrangle; 

,..I 
"\ 

'\ 

SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-157 

EXPLANATION 

...,...~- - Gabbroic intrusive rocks 

X 

Alkalic intrusive rockn 

a 

SOURCE OF GEOLOGIC MAPPING 

1. Snavely and Vokes, 1949; and Snavely, unpublished 

data. 

2. Baldwin and Roberts, 1952. 

3. Baldwin, Brown, Gair, and P·~ase, 1955. 

4. Baldwin, 1947. 

5. Vokes, Norbisrath, and Snavely, 1949, modified 

by Snavely. 

6. Baldwin, 1956a. 

l) 7. Vokes, Myers, and Hoover, 1954. 

8. Baldwin, 1956b. 

9: Vokes, Snavely, and Myers, 1!}51. 

~ 0 10 15 MILES 

~~~~----~~-~ 

~ 

~ 

t;) 

~ 

~ 

43°45' 

124°00' 123°45' 123°30' 123°15' 123°00' 

FIOUJtE 344.1.-Distribution of upper Oligocene gabbroic anJi alkalic intrusive rocks in the central part of the Oregon 

Coast Range. 
D-158 GEOLOGICAL SURVEY RESEARCH 1 9 6 1 

the original extent of this sill was probably more than 

200 square miles. Camptonite forms the stock at 

Cougar Mountain in the Euchre Mountain quadrangle 

and is present in sills and dikes in the same general 

area. 

The contacts behYeen intrusives and country rock 

are usually sharp; no evidence for stoping or assimilation has been found. Most commonly the sedimentary 

rocks are weakly metamorphosed only at (or for a few 

feet beyond) the contact, but above some of the thicker 

sills the country rock has been transformed into 

hornfels. 

GABBROIC SILLS 

The thick gabbroic sills comprise a gradational sequence of rock types that includes basalt of the chilled 

border facies, granophyric gabbro and granophyric 

diorite in the ma.in body, and less abundant irregular 

masses of a pegmatitic facies and cross-cutting veins of 

quartz-feldspathic micro pegmatite. Preliminary results of petrographic studies and analyses of samples 

collected from many of the larger bodies indicate that 

the rock types are similar to those found in other intrusives· described elsewhere in the world (Wager and 

Deer, 1939; Walker and Poldervaart, 1949; Iiotz, 1953; 

Walker, 1940, 1958). 

The Oregon intrusive bodies range in composition 

·from gabbro to diorite and, '"ith few exceptions, exhibit a micropegmatitic intergrowth of quartz and feldspar in thin sections. 

Plagioclase feldspar, the most abundant mineral, 

commonly occurs as strongly zoned tablets that range 

outward from cores of calcic labradorite· to rims of 

calcic andesine in the granophyric gabbro and from 

calcic andesine to sodic andesine in the granophyric 

diorite. The abundant small plagioclase laths in the 

groundmass have the same composition as the rims of 

the larger crystals. 

On the average, considering both gabbro and diorite, 

the rocks of the sills consist of about 50 percent plagioclase (An:io-6:.), about equal amounts (10 to 20 percent 

each) of pyroxene (predominantly augite, pigeonite, or 

ferroaugite), quartz-feldspar intergrowth, and secondary minerals, and less than 5 percent o:f olivine, quartz, 

and opaque minerals. Olivine and quartz are present 

in some, but not in all sections studied. 

The average of 21 chemical analyses of ga.bbroic rocks 

from the thicker sills of the Oregon Coast Range is 

given in table 344.1, column 2. This average is nearly 

identical to the chemical composition of a basalt sample 

from the chilled margin of the Mount Hebo sill (table 

344.1, column 1). Inasmuch as the two are so similar, 

the average in column 2 probably represents the com- · 

position of the original magma. The Coast Range 

average is similar to the average. tholeiitic andesite of 

Nockolds (1954) shown in table 344.1, column 5. Gabbroic rocks of Oregon, however, conta.in more SiO:~ 

and less MgO and CaO than Nockolds' average. 

The analysis of the chilled facies and the average 

analysis of the gabbroic rocks fall within }{uno's ( 1960, 

p. 137, fig. 10) field for tholeiite but plot near the boundary of his alkali dolerite field. The same analyses, 

whel). plotted on a diagram of Murata (1960, p. 250, fig. 

2), fall near the differentiation trend line for the tholeiitic basalt series, but are displaced slightly toward 

the trend line for the alkalic basalt series. The differentiation trends of the Oregon Coast Range intrusive 

rocks and the Skaergaard liquids of Wager and Deer 

( 1939) are compared in the FMA diagram, figure 344.2. 

Both the Oregon Coast Range and Skaergaard magmas 

were progressively enriched in iron during the greater 

part of crystallization and were enriched in alkalis (and 

in silica, which does not plot on the diagram) near the 

end of crystallization. The diagram shows that magnesia-rich rocks of the Oregon_ Coast Range, and presumably the magma that gave rise to them, are relatively richer· in alkalis than comparable Skaergaard 

liquids. This relatively high alkali content seems to be 

typical of most Oregon Coast Range igneous rocks, for 

available analyses indicate that the alkali content in the 

basalt flows of the widespread lower Eocene and more 

F 

FeO o------o 

.,_ Skaergaard ____ _ Oregon Coast Range 

AL---------------------------------------~M 

K20 + Na20 MgO 

FIGURE 344.2.-Comparison of differentiation trends of Oregon 

Coast Range gabbroic intrusive rocks and the Skaergaard 

intrusion (in weight pereent). Samples include basalt and 

gabbro from the chilled border facies, granophyric. gabbro, 

granophyric diorite, pegmatitic facies, and qnartz-feldspathic 

micropegmatitic veins. 

.. _ 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-159 

TAJH-JD 344.1.-Average chemical analyses (in percent) and norrns of Oregon Coast Range gabbroic and alkalic intru.sive rocks and averages 

· of similar magma types 

[Annlysos In columns 1-4 by I. H. Uarlow, S.D. Dotts, Gillison Chloe, P. L. D. Elmore, J. W. Goldsmith, R. L. Hill, M.D. Mack, and D. F. Powerg] 

1 2 3 4 5 6 I 7 

Average Average I Range Average I Range Average I Range Average Average I Avo<Oge 

Chemical analyses 

Si 02- -- __ .. _--- .. ---- 54. 8 54. 5 50. 5 -58. 0 59. 0 57. 6 -60. 0 

Al203---------- ~--- 13. 3 13. 1 11. 0 -15. 0 18.' 7 18. 5 -18. 8 

Fc203-------------- 1.6 3. 5 1.3 - 6. 3 3. 4 2. 4 - 4. 3 FuO _______________ 10. 8 9. 5 6. 7 -12. 8 2. 3 1.6 - 3. 2 ~gO ______________ 3. 3. 2:3 . 84- 4. 0 . 24 . 08- 0. 55 Cao _______________ 7. 1 6. 4 4. 8 - 7. 7 1.2 . 91- 1.8 

N t120 ______ -- __ - _- _ 3. 4 3. 3 2. 6 - 6. 2 8. 4 7. 8 - 9. 2 

K20--------------- 1.6 1.5 . 48- 2. 1 4. 0 3. 6 - 4. 3 H20+ ______________ . 57 1.5 . 32- 2. 5 1.6 . 98- 2. 5 f[2Q- ______________ . 27 ·. 1.0 . 25- 2. 8 . 40 . 14- 0. 60 

Ti02--------------- 2. 0 2. 0 1.4 - 3. 6 . 15 . 13- 0. 20 

P206--------------- . 35 . 53 . 16- 0. 94 . 21 . 14- 0. 30 ~nQ ______________ . 21. . 25 . 17- 0. 36 . 22 17- 0. 24 

C02 ________ - ______ -------- _k ______ 

------------ -------- ------------

40. 6 38. 7 -41. 8 

13. 1 11.4 -14. 4 

7. 1 6. 9 - 7. 2 

8. 1 6. 9 - 9. 5 

6. 0 5. 2 - 7. 3 

1.0. 2 9. 7 -10. 6 

3. 8 3. 6 - 4. 2 

1.9 1. 7 - 2. 2 

2. 9 2. 4 - 3. 1 

. 39 . 24- 0. 50 

3. 7 3. 0 - 4. 6 

1.6 1.4 - 1.9 

. 25 . 24- 0. 27 I 

-------- ------------

51. 43 

13. 05 

3. 36 

9. 74 

5. 28 

8. 78 

3. 18 

1. 04 

. 87 

-------- 2. 60 

. 45 

. 19 

--------

61. 95 

18. 03 

2. 33 

1. 51 

. 68 

1. 89 

6. 55 

5. 53 

----·-~~- } . 'i'3 

18. 

. 13 

--------

40. 7 

16. 0 

5. 4 

7. 8 

5. 4 

9. 3 

3. 2 

1.7 

2. 6 

3. 8 

.6 

. 1 

2. 9 

0 

2 

3 

4 

3 

6 

3 

6 

2 

6 

2 

6 

7 

Norms 

q z- - - - - - - - - - - - - - - - - 6. 3 11. 3 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 3. 2 - - - - ·- - - - - - - - - - - -

or_________________ 9. 5 8. 9 ------------ 23.9 ------------ 11.1 ------------ 6. 1. 32.8 10.6 

;··\ nb_________________ 28. 8 27. 8 ------------ 54. 0 ------------ 13. 6. ____________ 27. 2 54.0 13. 6 

an_________________ 16.1 16.4 ------------ 1. 4 ------------ 13.1 ------------ 18.1 3. 3 23.9 

ne_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 9. 1 _ _ _ _ _ _ _ _ _ _ _ _ 9. 9 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . 6 7. 4 

CnSi 03- _ _ _ _ _ _ _ _ _ _ _ _ 6. 8 4. 9 _ _ _ _ _ _ _ _ _ _ _ _ 1. 9 _ _ _ _ _ _ _ _ _ _ _ _ 11. 4 _ _ _ _ _ _ _ _ _ _ _ _ 9. 2 ~t 1 7. 9 

~gSi03------------ 8.3 5.8 ____________ 1.6 ____________ 8.3 ____________ 13.2 1.6 5.6 

FeSi03

_____________ 15.6 11.. 6 ____________ . 6 ____________ 2. 0 ____________ 11. 1 ________ 1. 6 

l\1g2Si 0 4

__ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ • 1 _ _ _ _ _ _ _ _ _ _ _ _ 4. 7 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 5. 6 

Fe2Si 0 4 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ • 1 _ _ _ _ _ _ _ _ _ _ _ _ 1. 2 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 1. 6 

rnt________________ 2. 3 5.1 ------------ 4. 9 ------------ 10.2 ____________ 4. 9 3. 3 7. 9 

il__________________ 3. 8 3. 8 ------------ . 3 ------------ 7. 0 ------------ 5. 0 1. 4 7. 5 

8 p- - - - - - - - - - - - - - - - - 1. 0 1. 3 - - - - - - - -·- - - - - - - - - - - - - - - - - - - - - - - - 3. 7 - - - - - - - - - - - - 1. 1 . . 4 1. 3 

Number of 

n.nn.lyses ___ _ 21 

1. Basalt from upper chilled border of sill at Mt. Hobo, Oregon Coast Range. 

2. A vcrago gabbrolc intrusive rock, Oregon Coast Range. 

a. A vcmgc ncphcllno syenite porphyry, Oregon Coast Range. 

4. A vcrngo camptonlto, Oregon Coast Range. 

5. A vcmgo tholeiitic andesite, Nockolds (1954, p. 1019). 

0. A vcmgc alkali trachyte, Nockolds (1954, p. 1016). 

7 3 26 15 15 

7. A vcragc camptonltc, Johannsen (193S, p. 65); norm calculated by the authors; C02 was assumed to be secondary. 

restricted upper Eocene and middle Miocene rocks is 

higher than thn,t of the alkali basalts of N ockolds ( 1954. 

p. 1021). 

ALKALIC ROCKS 

The nepheline syenite porphyry at Blodgett Peak 

hn.s a trn.chytoidal texture made apparent by conspicuous euhedral and complexly twinned phenocrysts of 

albite (about An10 ) 2 set in a medium-gray groundmass. 

~ Optical <letermlnn tlon shows Nx as 1.532 ± 0.003 and 2V as about 

(-)55°. 

The average mineral composition of the nepheline sye-

.nite at Blodgett Peak consists of about 50 percent albite 

laths in the groundmass, 10 to 15 percent each of albite 

phenocrysts, nepheline and analcite, and seconda.ry minerals, 5 to 10 percent aegirine and aegirine-augite, 3 to 

5 percent olivine and opaque minerals, and 1 to 2 percent 

riebeckite. Deuteric analcite has partially replaced 

both the nepheline and the albite, ·and also occurs as 

crystals in rare miarolitic cavities. At Table Mountain 

the albite phenoci·ysts have been almost completely altered to sericite and chiy minerals. 
D-160 GEOLOGICAL SURVEY RESEARCH 19 6 1 

The average chemical composition of 7 samples of 

nepheline syenite porphyry from the Oregon Coast 

R.ange is listed in table 344.1, column 3. This average 

is similar to Nockolds' (1954) average alkali trachyte 

(table 344.1, column 6). The syenite of the Coast R.ange 

contains less SiOz and 1{20 and more N azO and total 

iron. These differences in silica., potash, and soda result in less orthoclase and more nepheline in the norm 

for the average Oregon syenite. 

A lamprophyre, camptonite, forms the Cougar Mountain stock and associated dikes and sills in the northeastern part of the Euchre Mountain quadrangle (fig. 

344.1). The most common facies of camptonite is a 

porphyritic rock composed chiefly of randomly oriented 

black equant crystals of hornblende in a. medium-gray 

fine-grained groundmass. Pegmatoidal lenses and 

stringers are not uncommon, and contain long slender 

prismatic crystals of hornblende as much as 20 mm in 

length. A dike of biotite-rich camptonite intrudes the 

Tyee formation along the Siletz River in the west-central part of the Euchre Mountain quadrangle. 

In thin sections the camptonite is characterized by 

phenocrysts of reddish-brown markedly pleochroic barkevikitic hornblende, which form 30 to 40 percent of 

the rock. Plagioclase feldspar phenocrysts (An45-55) 

form 10 to 25 percent; titaniferous augite, usually with 

reaction rims of aegirine-augite or aegirine, as much as 

25 percent; opaque minerals, 3 to 10 percent; and apatite, 1 to 2 percent. Deuteric analcite and its alteration 

products constitute as much as 30 percent of the rock. 

Chemical analyses of camptonite from the Oregon 

Coast R.ange (table 344.1, column 4) compare closely 

with the average listed by Johannsen (table 344.1, 

column 7). Camptonite from Oregon, however, contains less Alz03 and more P 20 5 than Johannsen's average. The greater amount of alumina in Johannsen's 

average results in a much greater percentage of anorthite in the no.rm. 

CONCLUSIONS 

The close association in space and time of emplacement of the alkalic and gabbroic intrusives in the Oregon . Coast Range suggests that they are comagmatic. 

Available chemical ·data indicate that the parent magma 

was probably transitional between the tholeiitic a~d 

alkalic series. It seems reasonable to assume that a 

magma of intermediate composition would give rise to 

two divergent rock types. Therefore, the writers speculate that the ·alkalic rocks are an early product of differentiation of an alkali-rich tholeiite generated in a 

belt transitional to the continent and the Pacific Basin. 

It should be stressed that the results summarized here 

are preliminary and that additional petrographic and 

analytical data are needed before more than conjecture 

can be attempted concerning the magmatic evolution 

o~ these Oregon rocks. 

REFERENCES 

Baldwin, E. M., 1947, Geology of the Dallas and Valsetz 

quadrangles, Oregon : Oregon Dept. Geology and Mineral 

Industries Bull. 35, 61 p. 

--· - 1956a, Geology of the Marys Peak and Alsea quadrangles, Oregon: U.S. Geol. Survey Oil and Gas Inv. Map 

OM-162. 

--1956b, Geologic map of the lower Siuslaw River area, 

Oregon: U.S. Geol. Survey Oil and Gas Inv. Map OM-186. 

Baldwin, E. M., Brown, R. D., Jr.,. Gair, J. E., and Pease, 

l\f. H., .Jr., 1955, Geology of the. Sheridan and McMinnville 

quadrangles, Oregon:· U.S. Geol. Survey Oil and Gas Inv. 

Map OM-155. . 

Baldwin, E. M., and Roberts, A. E., 1952, Geology of the Spirit 

Mountain quadrangle, northwestern Oregon: U.S. Geol. 

Survey Oil and Gas Inv. l\~ap OM-129. 

Hotz, P. E., 1953, Petrology ··of granophyre in diabase near 

Dillsburg, Pennsylvania: Geol. Soc. America Bull., v. 64, 

no. 6, p. 675-704. 

.Johannsen, Albert, 1938, A descriptive petrography of the 

igneous rocks, volume 4: Chicago, Ill., Chicago Univ. Press', 

523 p. 

Kuno, Hisashi, 1960, High-~lumina basalt: Jour. Petrology, 

v. 1, pt. 2, p. 121-145. 

Murata, K .. J., 1960, A new method of plotting chemical analyses 

of basaltic rocks: Am. Jour. Sci., v. 258-A, Bradley volume, 

p. 247-252. 

Nockolds, S. R., 1954, Average chemical compositions of some 

igneous rocks: Geol. Soc. America Bull., v. 65, no. 10, p. 

1007-1032. 

Roberts, A. E., 1953, A petrographic study of the intrusive at 

Marys Peak, Benton County, Oregon: Northwest Science, 

v. 27, no. 2, p. 43-60. 

Rogers, A. F., Howe, H. V., and Staples, L. W., 1941, Trachytoid 

nepheline syenite from Lincoln County, Oregon [abs.] : 

Geol. Soc. America Bull., v. 52, no. 12, pt. 2, p. 1955. 

Snavely, -P. D., Jr., Baldwin, E. M., Roberts, A. E., and Isotoff, 

Andrei, 1950, Large intrusive bodies in the Central Coast 

Range of Oregon [abs.]: .Geol. Soc. America :kull., v. 61, 

no. 12, pt. 2, p. 1503-1504. 

Snavely, P. D., Jr., and Vokes, H. E., 1949, Geology of the 

coastal area from Cape Kiwanda to Cape Foulweather, 

Oregon: U.S. Geol. Survey Oil and Gas Inv. Prelim. 

Map 97. 

Vokes, H. E., Myers, D. A., and Hoover, Linn, 1954, Geology 

of. the west-central border area of the 'Villamette Valley, 

Oregon: U.S. Geol. Survey Oil and Gas Inv. Map OM-150. 

Vokes, H. E., Norbisrath, Hans, and Snavely, P. D., Jr., 1949, 

Geology of the Newport-Waldport area, Lincoln County, 

Oregon: U.S. Geol. Survey Oil and Gas Inv. Prelim. 

Map 88. 

Vokes, H. E., Snavely, P. D., Jr., and Myers, D. A., 1951, Geology 

of the southern and southwestern border areas, 'Villamette 

Valley, Oregon: U.S. Geol. Survey Oil and Gas Inv. Map 

OM-110. 
,~· 

,•'''\ 

SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-4il5 D-161 

Wager, L. R., und Deer, W. A., 1939, The petrology of the 

Skuergnurd intrusiou, Kaugerdlugssuaq, East Greenland, 

in Pt. 3 of Geological investigations in east Greenland, 

Mecldelelser om Gronlund, v. 105, no. 4, 352 p. 

Walker, Frederick, 1!)40, Differentiation of the Palisades 

diabase, New .Jersey: Geol. Soc. America Bull., v. 51, p. 

1059-1106. 

"'alker, Frederid\, 1908, The causes of variation in dolerite intrusions, 'i-11. Dolerite, n sym})OSium: Tasmania Univ., Hobart [Symposia no. 1], p. 1-25. 

'Valker, Frederick, and Poldervaart, Arie, 1949, Karroo dolerites 

of the Union of South Africa: Geol. Soc. America Bull., 

v. 60, no. 4, p. 591-706. 

345. RELATION BETWEEN DEFORMATION, METAMORPHISM, METASOMATISM, AND INTRUSION ALONG THE 

NORTHWEST BORDER _ZONE OF THE IDAHO BATHOLITH, IDAHO 

By ANN A HrETANEN, Menlo Park, Calif. 

The grade of metamorphism of the Belt series northwest of the Idaho batholith increases toward the batholith through a distance of about 40 miles from the 

greenschist facies through the epidote-amphibolite 

facies to the sillimanite-muscovite subfaciek of the 

n.mphiibolite facies (fig. 345.1). . 

The rnineralogic changes are best exhibit~d in the 

micaceous granofelses, phyllites, and schists that are 

metamorphosed equivalents of parts of the 'Vallace 

formation described by R.ansome and Calkins (1908) 

in the Coeur d'Alene district and by Umpleby and 

.Jones ( 1923) and 1Vagner ( 1949) near A very. In the 

micaceous rocks of the biotite-almandite subfacies of 

the epidote-amphibolite facies the late porphyroblasts 

are almandite and biotite, usually 2 to 3 mm in diameter; in places these minerals are partly altered to 

chlorite. In the schists of the staurolite-kyanite subfacies the porphyroblasts are staurolite and kyanite; 

the staurolite crystals are 2 to 6 em long and those of 

kyanite are even larger. Both of these minerals contnial abundant inclusions of quartz distributed along 

surfaces that are continuous with those of the folded 

beds in the enclosing schist. ~{any almandite grains 

are enclosed by later staurolite and kyanite and others 

have pushed the foliation aside. Some almandite crystals have a zone of inclusions of small quartz grains 

near their centers and another along their borders indicating two stages of synkinematic crystallization. 

These two s~ag~s (early and late· phase in fig. 345.2) 

n.re n.lso indicated by pseudomorphs consisting of kyanite, almandite, and muscovite but hn.ving the outlines 

of staurolite twins. A still later stage is recorded by 

alteration of kyanite to muscovite. In. a zone next to 

the batholith the only stable polymoq~h of Al2Si05 

is sillimanite, which forms needles oriented parallel to 

the fol ia.t.ion. Some of the garnet., biotite, and sillimanite continued to crystalliz3 in a later stage. 

Many outcrops show two sets of folds, one on either 

a northeastward- or a northwestward-trending axis and 

another on an east-west axis. The northeastward- and 

northwestward-trending folds are parallel to the Nevadan (Jurassic) trends. The style of folding changes 

with the grade of metamorphism. In the greenschist 

facies large open folds are common and the foliation is 

parallel to bedding, to axial planes, or to nearby fault 

zones. The folds become increasingly tighter to the 

south, and in the zone next to the batholith steep isoclinal folds or overturned flow :folds prevail. The axial 

plane foliation and cleavage folds are best developed in 

micaceous layers metamorphosed to the epidote-amphibolite facies; they are rare in the a.mphibolite facies near 

the batholith. Concentric folds with foliation parallel 

to the bedding are common in thin-bedded quartzite in 

all metamorphic zones. 'Vhere several sets of folds occur, the style of folding in all sets in a given metamorphic zone is similar, except as it is modified by the differences in competency of the materials folded. The 

northeastward- and northwestward-trending folds were 

formed simultaneously, and east-west folding, perhaps 

started in Precambrian time, was renewed during the 

.Jurassic period. Lineation is well developed in most 

rocks, and it is always parallel to one of the three fold 

axes. 

In many places along the northwestern contact zone 

of the batholith secondary hornblende, biotite, and andesine were developed· in garnet-mica schist, biotite 

gneiss, and diopside gneiss. Compa.rison of the chemical analyses of the normal metasediJnenta.ry rocks with 

those of the andesine and hornblende-bearing parts of 

the sa.me strata indicates introduction of Ca, Fe, Mg, 

and loca.lly Na, and removal of l{ and Si during the 

development of the secondary minerals. The secondary 

minerals show no preferred orientation and in many 

places obliterated the earlier structures, suggesting tha.t 
D-162 

47° 

10' 

(unmapped) 

GEOLOGICAL SURVEY RESEARCH 1 9 6 1 

116° 00 1 

0 

I 

0 

I 

10 

115° 40' 9 MILES ', 

15 KILOMElERS 

EXPLANATION 

~ H Columbia River 

basalt 

(/) 

:::> 

G .. l:;: ~~uam } ~ monzonite ~ .... 

u (/) 

::J 

~ - ro ffio~ <t:f-f- Quartz diorite 0: w and tonalite :::> 0: .., u 

Anorthosite 

Mainly bytou·niteandesine TO('k U"ith 

some hornble11dP 

) 

~ ~ - :::> 

0: 0 

~ow ct:f-U 

u <( 

w f- 0: w ll. 0: u 

D l~ 

)

. ~ 

Belt series ~ 

Quartzite. gnf'i,,,, U 

and srhi.•t. interbedded W 

Contact 

Dashed where npprorimntf'lll 

lorn ted 

Fault 

Dashed u•here approrimntely 

I<X'nted 

0: 

ll. 

FIGURE 345.1.-Sketch map showing the major rock units, distribution of some of the index minerals of metamorphic facies, 

and rearrangement of elements northwest of the Idaho batholith. The rocks south of the sillimanite isograd were metamorphosed to the amphibolite facies, those between the biotite and sillimanite isograds to the epidote-amphibolite facies, 

and the rocks north of the biotite isograd to the greenschist facies. Mainly Na was introduced into the anorthosite bodies. 

·

.~ 
('' 

Facies 

Biotite·almandite 

subfacies 25 to 

35 miles north 

from the batho· 

lith 

Staurolite· 

kyanite sub· 

facies 15 to 25 

miles north from 

from the batho· 

lith 

Sillimanite· 

muscovite sub· 

facies about 15 

mile·wide zone 

next to the 

batholith 

SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-163 

Minerals 

muscovite 

biotite 

almandite 

tremolite 

microcline 

albite 

epidote 

scapolite 

chlorite 

muscovite 

biotite 

almandite 

staurolite 

kyanite 

actinolite 

diopside 

microcline 

oligoclase 

epidote 

scapolite 

muscovite 

biotite 

garnet 

sillimanite 

oligoclase 

actinolite 

hornblende 

diopside 

andesine 

bytownite 

andesine 

Postkinematic 

Synkinematic crystallization crystallization (Jurassic) (Early Cretaceous) 

Early phase Late phase 

I 

the metasomatic introduction of elements occurred after 

the major deformation. The basified zone is about 10 to 

12 miles wide and about 15 to 20 percent of the metasedimentary rocks were affected. Potassium feldspar, 

which is a common metamorphic mineral in many stratigra:phic units farther from the batholith, is very scarce 

or absent in the equivalent units in the basified aureole 

and also in a zone, 5 to 10 miles wide, outside it. In a 

zone 20 to 40 miles northwest of the batholith, the only 

change in chemical composition during the metamorphism was the loss of H20 and C02 that took place at 

certain temperature intervals along the facies boundaries. 

The largest intrusive bodies in the a.rea are quartz 

diorite and quartz monzonite. The contacts of quartz 

diorite are in part concordant n.nd in part discordant. 

Foliation is well developed in many srnall bodies in the 

western part of the area and near the contacts of the 

larger bodies, but the centers o-f the large bodies are 

massive. These structural rela.tions suggest that the 

emplacement of small intrusive bodies began during 

the deformation but that the emplacement and crystallization of the largest bodies followed the deformation. 

The metamorphosed and metasomatized rocks of the 

inner contact zone and the quartz diorite are cut by the 

quartz monzonite that makes up most of the present 

exposed batholith. The lead-alpha ages of the batholithic rocks average 108 million years, which dates the 

. intrusion as late Early Cretaceous (Larsen and others, 

1958). Because the minerals in the rocks of the sillimanite-muscovite subfncies, which were invaded, were 

stable in the temperature and pressure of the intrusion, 

new minerals formed only where elements were 

introduced. 

These .observed relations are interpreted as follows: 

The rearrangement of elements in the immediate 

vicinity of the present batholith began during the· formation of the quartz monzonite magma by partial melting of a part of the crust at depth. The melting 

probably was an ultimate result of elevated temperatures during the deformation in the lower part of the 

crust. If so, the first melt would be granitic in composition (3, in fig. 345.3) a.nd the zone around the 

developing magma would be relatively enriched in Ca, 

Fe, and ~1g by subtraction o:f granitic components (2, 

in fig. 345.3). When the temperature rose (or the pressure decreased) the magma would become more mafic 

( quartz-monzonitic) and finally the basified aureole 

around it would also melt partially to form a. quartz 

diorite magma. This magma invaded its roof and ga.ve 

off solutions carrying N a, Ca, Fe, and Mg, which adFmun1~ 345.2.-Sequence of crystallization in various metamor- vanced into the country rocks, reacted with their minphic facies northwest of the Idaho batholith. erals, and formed local segregations of hornblende, 
D-164 GEOLOGICAL SURVEY RESEARCH 1 9 6 1 

A B 

FIGURE 345.3.-Schematic cross-section showing interpretation of the relation between metamorphism and intrusion along the 

northwest border zone of the Idaho batholith during late Mesozoic time. Sketch A shows (1) the zone of high-grade, 

essentially isochemical, metamorphism during Jurassic time; (2) the zone of rocks basified by depletion of granitic components; and (3) the magma produced by partial melting and aggregation. Sketch B shows quartz diorite (4) which 

was for.med from the basified rocks (2 of sketch A), by partial melting and recrystallization. A new basified zone 

(basic front) (5) was formed around the quartz diorite by metasomatic introduction of Na, Ca, Fe, and Mg from 

the quartz dioritic magma during Early Cretaceous time. The entire series of metamorphic, metasomatic, and early 

magmatic rocks was then intruded by the quartz monzonite that makes up the batholith proper (6). 

biotite, and andesine ( 5, in fig. 345.3). During an early 

stage of this metasomatism the e,lements were carried 

in solutions that moved in open channels; at this stage 

hornblende and andesine crysta1lize,d together, forming 

small bodies of metasomatic quartz diorite. Later, 

when the pore liquids became stationary and the elements moved only by diffusion, the fernie and salic 

constitutents crytallized in separate places, the former 

giving rise to segregations of hornblende and biotite 

and the latter to secondary andesine that replaced 

quartz in the schist and bytownite in the anorthosite. 

Much of the potassium and silicon that have been 

removed from the contact aureole of the batholith 

probably migrated to the granitic and quartz monzonitic magmas during their formation. On the basis 

of the above· discussion, it is concluded that the chemical 

differences between the quartz diorite and quartz 

monzonite series is due to the differentiation of elements 

during the formation of the magmas rather than during 

their crystallization. The crystallization differentiation of the quartz monzonite magma gave rise to a 

normal rock series ranging from olivine and pyroxene 

gabbros to granite, whereas the quartz diorite magma 

yielded hornblendite, hornblende gabbro, quartz diorite, 

and tonalite. 

REFERENCES 

Larsen, E. S., Jr., Gottfried, D., Jaffe, H. ,V., and 'Varing, C. L., 

1958, Lead-alpha ages of the Mesozoic batholiths of 

western North America: U.S. Geol. Surv.ey Bull. 1070-B, 

p. 35-62. 

Ransome, F. L., and Calkins, F. C., 1!)08, The geology and ore 

deposits of the Coeur d'Alene district, Idaho: U.S. Geol. 

Survey Prof. Paper 62, 203 p. 

Umpleby:, J. B., and Jones, E. L., 1923, Geology and ore deposits 

of Shoshone County, Idaho: U.S. Geol. Survey Bull. 732. 

156 p. 

Wagner, W. R., 1949, The geology of part of the south slope of 

the St. Joe Mountains, Shoshone County, Idaho: Idaho Bur. 

Mines and Geology, Pamph. 82, p. 1-48. 

) 

'f 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-165 

346. DEFORMATION OF THE EPICENTRAL AREA, HEBGEN LAKE, MONTANA, EARTHQUAKE OF 

AUGUST 17, 1959-DUAL-BASIN CONCEPT 

By IRVING J. WrrKIND, Denver, Colo. 

The geologic work completed in the Hebgen Lake 

· area (fig. 346.1) since the earthquake of August 17, 

1959 (Witkind, 1959, 1960; Niles, 1960) has yielded 

many detailed data on both relative and absolute 

ground movement in some parts of the area, but very 

little in other places. Two different interpretations of 

the nature and pattern of structural deformation stem 

from the available data. One interpretation (Myers 

and Hamilton, Art. 347), suggests subsidence of a 

single large basin, transverse to the major topographic 

elements. The other interpretation, here called the 

"dual-basin concept", suggests unequal subsidence of 

two independent basins, one on each side of the core of 

the Madison Range (fig. 346.2). Whichever interpretation is correct, it seems clear that the crest of the 

range, in a relative sense, is higher in relation to the 

adjacent downthrown basins than it was before the 

earthquake. 

During the earthquake, new fault scarps appeared at 

several localities throughout the epicentral area. The 

major scarps coincide with, or are near, previously 

mapped normal faults which trend generally northwest and dip southwest. Two of these scarps, the Red 

Canyon and Hebgen fault scarps, are north of Hebgen 

Lake (fig. 346.1) and coincide with the northwesttrending Red Canyon and Hebgen faults respectively. 

Minor fault scarps, along the west front of the Madison Range (fig. 346.1), coincide with the well-established Madison Range fault. All these fault scarps 

clearly result from reactivation of the faults. 

The Red Canyon and Hebgen faults are considered 

to be the fundamental faults of the earthquake, or at 

least surface modifications of a deep fault. This is 

supported by a preliminary analysis of seismograms of 

this earthquake which suggest "strike of the fault plane 

N. 80°±12° W.; clip 55°±9° SW.; strike of the auxiliary plane N. 62° ± 15° W." (Ryall, 1961, p. 63). 

The geologic pattern of the area indicates that each 

of the faults- Red Canyon, Jiebgen, and Madison 

Range-is marginal to one or more crustal blocks which 

have subsided repeatedly in the past (Pardee, 1950, p. 

369; Witkind, 1960, p. 3±). Thus, the Red Canyon and 

FIGURE 346.1.-Shaded relief map of the eJ)icentral area, Hebgen Lake. :\Iont., earthquake of .August 17, 19:39. 
D-166 GEOLOGICAL SURVEY RESEARCH 1 9 6 1 

Wade ··, Lake 

111 °30' 

11 Prehistoric fault scarp, 1!1;11 30 feet high, along 111111 _front of Madison ---...1'..,. Range 

~---.b.. ....... ,/ 

~ " 

Stagge" y,,}\ MADISON 

Ranch I 11'l- SLIDE l r~MADISON RANGE 

1 :::: FAULT SCARP 

Missouri Flats I r2 

I /2' . '~:: 

f.,~// I tMADISON RANGE 

/ FAULT SCARP 

~.J.. I 

I 

I 1: I= 

EXPLANATION 

Isobase of absolute subsidence 

Dashed where locatwn uncertain. lsoba•e interval 4feet 

Major fault scarp formed during earthquake 

Height more than Sfeet. Ticks are on downthrown side. 

Point at which scarp height mensured marked by + 

+ Minor fault scarp formed during earthquake 

Height less than 3 feet. Tick.~ are on downthrown .•ide. 

Some scarps north of Madison River and Duck Creek arms 

of Hebgen Lake may be of slump origin. Point at which 

sca:rp height measured marked by + 

Bench mark of know~ absolute subsidence A 

Lakeshore point of measured absolute subsidence 

0 2 4 

111° 15' 

10 MILES 

Epicenter calculated by U.S. Coast 

and Geodetic Survey e 

L---L---~--~--~---L------------------~ 

FIGURE 346.2.--Absolute subsidence during Hebgen Lake earthquake-dual-basin concept. Contours based on releveling 

of bench marks and road profiles by the U.S. Coast and Geodetic Survey; measurements of lakeshore tilting by W. B. 

Myers, W. H. Hays, and Warren Hamilton; and measurements of scarp heights by I. J. ·witkind~ J. B. Epstein, 

W. B. Myers, Warren Hamilton, ~nd W. H. Hays. 

Hebgen faults flank both the Red Canyon and Hebgen 

Lake blocks (fig. 346.2). Simihirly, the segment of the 

Madison Range fault that was reactivated is along the 

east edge of the crustal block underlying the Missouri 

Flats basin (fig. 346.2), part of the much larger Madison basin. 

During the earthquake these blocks subsided unevenly. · Their general deformational pattern is shown 

locally by the new shoreline of a tilted lake, by measured displacement along new fault scarps, and ·by precise level data determined by the U.S. Coast and Geodetic Survey. 

I believe that this subsidence of local crustal blocks 

is a direct result of the .broad epeirogenic uplift and 

arching which this region has been undergoing since 

late Cenozoic (Pardee, 1950, p. 403). 

The dual-basin concept, based on subsidence of local 

crustal blocks, holds that the West Yellowstone and 

Missouri Flats basins, to the east and west of the Madison Range, respectively, subsided during the earth-
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENiCES, ARTICLES 293-435 D-167 

quake, but the core of the Madison Range remained 

fairly stable. The axes of these two basins are subparallel but not connected. 

The west half of the West Yellowstone basin, and 

parts of the adj ncent mountains to the north and west, 

subsided during the earthquake. This subsided area is 

underlain by the Red Canyon and Hebgen Lake crustal 

blocks (fig. 846.2). Of .these, the Red Ca,nyon block 

of about 20 square miles includes part of the mountains 

north of the lake. The Hebgen Lake block, although 

very much larger, is of uncertain areal extent. It includes the west half of the 'Vest Yellowstone basin and 

the east flank of the core of the Madison Range. The 

northeastern edge of this block is bounded by parts of 

the I:Iebgen nnd Red Canyon faults. Its southern edge 

may be delineated by the local faults of small displacement which break the surficial deposits south of Hebgen 

Lake (fig. 346.2). · 

Near 1-Iebgen Lake, data on the amounts and pattern 

of movement are ample, for when the West Yellowstone 

basin, which includes Hebgen Lake, dropped and tilted 

northeasterly, it displaced the lake. Measurements of 

the old and ne'v shorelines, made by W. R. Myers, 

supply many of the data used to contour this part of 

the basin (fig. 346.2). 

The east. edge of the Missouri Flats basin has subsided the most near the Madison Range fault. Precise 

levels completed by the U.S. Coast and Geodetic Survey 

indicate subsidence of about 7 feet along former U.S. 

1-Iigh way 287 near the east edge of the basin. 

The fault scarps along the Madison Range fault are 

2 to 3 feet high, but these may not accurately reflect 

the absolute displacement (Witkind, 1960, p. 38). It is 

assumed that they do, and I interpret the isobase lines 

to show drag of the eastern edge of the basin along the 

Madison Range fault, comparable to the drag along 

the northeast edge of the Hebgen Lake block (fig. 

346.2). 

Elsewhere in the Missouri Flats basin, the data are 

inadequate to define a pattern of displacement. Several small lakes may have been tilted, but their former 

shorelines are submerged, for increased surface- and 

ground-water discharge since the earthquake has caused 

the lakes to rise. This; coupled with conflicting statements by local residents, makes it U:t;!Certain which of 

the lakes, if any; have been tilted. The exact pattern 

of this deformed basin will be in doubt until it is resurveyed topographically. 

The deformation pattern along the crest of the Madison Ra,nge is uncertain, for no data are presently available for this critical area. One interpretation (Myers 

and Hamilton, Art. 347) is that it subsided as much as 

13 feet at places. I suggest that maximum subsidence 

probably did not exceed 3 feet (fig. 346.2). The east 

flank of the range, within the Hebgen Lake block was 

flexed downward (fig. 846.2). Flow far to the west 

this downward warp extends is not established. Most 

of the pre-earthquake bench marks in the Madison 

River Canyon are concealed beneath the newly formed 

Earthquake Lake. 

It has been proposed that deformation of the Madison Range is shown by subsidence in M:adison River 

Canyon (Myers and Hamilton, Art. 347). A comparison of pre- and post-earthquake surveys of the U.S. 

Coast and Geodetic Survey and the Bu]['eau of Public 

Roads suggests that the canyon floor subsided from 

about 8 feet at Beaver Creek to about 7 :feet near Stagger's Ranch at the west mouth of the canyon (fig. 

346.1), but these data are equivocal. In the fall of 1960 

surveys by the Bureau of Public Roads showed recent 

changes of from 1.0 to 1.8 feet in elevation in the area 

between Beaver Creek and the Madison Slide (L. D. 

Tingey, w'ritten communication, 1961). It would seem 

that this part of the canyon was still not stable in 1961. 

The surveys show that 2,900 feet west of Beaver Creek 

the highway dropped about 20 feet; this compares to 

an 8-foot drop of the highway at Beaver Creek. This 

unusual and sudden change must be attributed to some 

factor other than absolute subsidence. I suggest that 

unequal compaction of the alluvial fill may be the 

cause; this. view is supported by the ma,ny sand spouts 

on the broad alluvial flat near Beaver Creek. Compaction of unconsolidated materials played an important role in the subsidence elsewhere in the area, and 

probably was a factor in the amount of subsidence 

determined for former U.S. Highway 287 where it 

enters the west end of the canyon near Stagger's Ranch. 

Here the road rests on unconsolidated sand and gravel. 

~1y hesitancy to accept the subsidence dn.ta in the Madison River Canyon stems chiefly from the uncertainty 

as to how much of the measured subsidence is due to 

true bedrock movement and how much is due to compaction of the surficial cover. The true pattern of 

deformation for the Madison Range willl be determined 

only by a r.esurvey of the bedrock crest. 

Available geologic and geodetic data, and the preliminary seismic solution for the earthquake fault, suggest 

that the Hebgen-Red Canyon fault zone is fundamental, 

and that deformation everywhere in the area is most 

extreme near faults. On this basis, subsidence of two 

basins seems reasonable. 
D-168 GEOLOGICAL SURVEY RESEARCH 1 9 61 

REFERENCES 

Niles, S. W., 1960, The Hebgen Lake earthquakes, in Billings 

Geol. Soc. Guidebook 11th Ann. Field Conf., West Yellowstone-Earthquake area, 1960: p. 24-30. 

Pardee, J. T., 1950, Late Cenozoic block faulting in western 

Montana: Geol. Soc. America Bull., v. 61, no. 4, p. 359-406. 

Ryall, A. S., 1961, Direction of faulting in the Hebgen Lake, 

Montana, earthquake of August 18, 1959 [abs.] : GeoL Soc. 

America, Cordilleran Section, 1961 Ann. Meeting, San 

Diego, Calif., Program. 

Witkind, I. J., 1959, The Hebgen Lake earthquake: GeoTillles, 

v.4,no.3,p.13-14. 

-- 1960, The Hebgen Lake, Montana, earthquake of August 17, 1959, in Billings Geol. Soc. Guidebook 11th Ann. 

Field Oonf., West Yellowstone-Earthquake area, 1960: 

p. 31-44. 

347. DEFORMATION ACCOMPANYING THE HEBGEN LAKE, MONTANA, EARTHQUAKE OF AUGUST 17, 1959-

SINGLE-BASIN CONCEPT 

By W. BRADLEY MYERS and WARREN HAMILTON, Denver, Colo. 

During the major (magnitude at least 7.1) earthquake 

of August 17/ 1959, in southwest Montana, an area at 

least 27 miles long and 14 miles wide subsided detectably. Maximum absolute subsidence was about 22 

feet, and a tract of ·at least 60 square miles dropped 

more than 10 feet, but there was almost no known elevation of the land above previous levels. 

Many details of this subsidence can be defined by 

the data obta.ined from level lines, scarp heights, and 

lakeshore tilting. The U.S. Coast and Geodetic Survey 

releveled bench marks on a line that passes through 

West Yellowstone, the northeast side of Hebgen Lake, 

Madison River Canyon, and Madison River. 

By constructing a. post-quake road profile from the 

individual Coast and Geodetic Survey level-rod readings, and comparing this with the known pre-quake 

profile of the highway, we obtained a continuous measure of subsidence between the bench marks. These new 

data show the maximum subsidence along Hebgen Lake 

to be 22 feet, rather than the 19 feet demonstrated by 

the most subsided bench mark. 

The new road-profile data are critical to the structural interpretation in Madison River Ca1~yon, which 

cuts directly through the ~1adison Range. (Bench 

marks in the canyon were mostly buried beneath the 

enormous landslide, triggered by the earthquake, and 

the new lake dammed behind it.) These data (fig. 

347.1) show that no warping occurred across the rangefront fault at the mouth of ~1adison River Canyon, and 

that both the Madison Range and ~fadison Valley in 

that area subsided equally 6 to 8 feet. The data also 

show that a topographic basin in Madison River Canyon between Hebgen Lake and Earthquake Lake subsided at least 12 feet, at least 6 feet more than the 

1 ·A.ugust 17 by local date; A.ugust 18 by Greenwich date. 

narrow part of the canyon between the topographic 

basin and Hebgen Lake. This basin has broad flats 

of thick alluvium and till and a gentle river gradient, 

whereas the Madison River Canyon is otherwise narrow 

and has a steep gradient, so that the increased subsidence in the basin was not unexpected. 

In Article 346, 'Vitkind states that the subsidence 

measured within ~fadison River Canyon was due partly 

to compaction and slumping, and, therefore, is equivocal in structural evaluations. He believes that subsidence in ~fadison Valley and 'Vest Yellowstone basin 

was due largely to structural deformation. This interpretation seems to assume that in Madison Valley, 

where sedimentary fill is thick, there was practically no 

compaction, but in Madison River Canyon, where fill 

was very thin, compaction unaccompanied by any 

noticeable slump away from nearby outcrops, produced 

most of the subsidence. 

We examined the prehistoric fault scarp at the mouth 

of Madison Canyon, and found no new breaks. Further, 

although Madison River there runs on thin alluvium 

and at places reaches bedrock, there was no apparent 

steepening of its gradient to suggest warping at the 

range front. 

In the upper part of Madison River Canyon (as was 

true also along Hebgen Lake except in obvious landslides), control points on bedrock subsided compatibly 

with those on surficial deposits,. so slumping and compaction of unconsolidated materials at these places contributed I ittle to the subsidence. 

The contours of absolute subsidence ( isobases) defined 

by these various data (fig. 347.1) can be drawn wit.h 

confidence near Hebgen Lake and along the level line, 

and with less confidence near the major new fault 

scarps, but elsewhere their l~cation is doubtful. 'Vhere 

.... . 
... 

\ 

SHORT PAPERS IN THE GEOLOGI·C AND HYDROLOGIC SCIENCES, ARTICLES 298-435 D-169 

111 "30' 

EXPLANATION 

----5--- Is~base of absolute subsidence 

Dusked where location uncertain. lsobase interval 4feet ± I I 

Major fault scarp fonned during earthquake 

Height more than 9feet.Ticks are on downthrown side. 

Point at which scarp height measured marked by t 

Minor fault scarp formed during earthquake 

Height less than 9 feet.. Ticks are on downthrown .•ide. 

111° 15' 

Epicenter calculated by U.S. Coast 

and Geodetic Survey e 

Some scarp:~ north of Madison River and Duck Creek a.rms 

of Hebgen Lake may be of slump origin. Point at which 

scarp height measu·red marked by t 

Bench mark of know~ absolute subsidence 6 

Lakeshore point of measured absolute subsidence c8 Road-profile point of known absolute subsidence Showing subllidence in feet. Shown only ·in Madison River canyon 

---t- Axis of basin of subsidence formed during 1959 earthquake 

Showing direction of plunge 

0 4 10 MILES 

JtwuHE 347.1.-Absolute subsidence during Hebgen Lake earthquake-single basin concept. Based on releveling of bench marks 

nnd rond profiles ·by the U.S. Coast and Geodetic Survey; measurements of lakeshore tilting by W. B. Myers, ,V, H. Hays, 

anrl 'Val'l'en Hamilton; and measurements of scarp heights by I. J. Witkind, J. B. Epstein, W. B. Myers, Warren Hamilton, 

uml W. H. Hays. 

the trmtd of t-he isobases is most closely controlled, near 

t'lte south half of I-:Iebgen Lake, it is westward; we 

assume that this trend continues into the Madison 

Hange, whereas "'Tit.kind (Art. :346) makes a contrary 

assumpt-ion t.hat the isobases define a more northedy 

trending basin of subsidence. Subsidence of the M:adison Range seems adequately demonstrated within Madison H.iver Canyon, and we infer that the range subsided 

· south of the canyon also. 

'Ve thus interpret the data to indicate a broad basin 

of new subsidence that plunges gently eastward across 

:Madison Valley, ~1adison Range, and "Vest Yellow604493 0--'61--12 

stone basin to Hebgen Lake. The basin, be it a single 

complex one as ''"e suggest, or two disconnected ones as 

'Vitkind suggests, ends obliquely and abruptly against 

three reactivated fault scarps, !5 to 20 feet high, which 

trend southeastward I1ear the northeast side of Hebgen 

Lake. All are dip-slip normal faults, upon which no 

tectonic strike-slip offset was recognized. Northeast of 

these scarps and their immediate disturbed zones, 

known elevn.tion or subsidence i:n 1959 was lim.ited to less 

than 1 foot. Of the three high scarps, two break Paleozoic sedimentary rocks, n.nd the third cuts thick Pleistocene deposits which hide bedrock structure. 
D-170 GEOLOGICAL SURVEY RESEARCH 19 61 

The two major faults in Paleozoic rocks (mapped by 

I. J. Witkind, J. B. Hadley, W. H. Nelson, and others) 

lie for most of their lengths between bedrock bluffs and 

the talus below them, and probably follow previously 

active faults. The faults at their west ends, however, 

cross bedrock ridges where there is neither structural 

· nor topographic evidence for previous faulting, and the 

new breaks appear hei·e to extend beyond older faulting. The faults are· nearly bedding-plane faults, and 

are limited to areas where the bedding dips steeply toward the subsidence basin. The trend of one of the 

faults swings with the bedding through a large arc in 

strike. Where bedding is oriented favorably to permit 

sliding down the dip, the measured subsidence is accounted for almost entirely by the height of new scarps. 

'Vhere attitudes are less favorable for sliding, subsidence was accomplished by a combi'nation of warping 

(to a maximum of %0 of new tilting) and faulting. 

These two major reactivated faults at the surface are 

thus closely controlled by fold structures, in Paleozoic 

rocks, which probably do not extend deeper than 1 mile. 

The surface scarps, therefore, cannot directly portray 

the pattern of deformation in deep basement rocks; 

rather, the surface breaks must be due to refraction or 

resolution of deeper faults or flexures into planes of 

easy near-surface slip. 

The third major 1959 fault scarp .extends farthest 

southeast and displaces early Wisconsin (late Pleistocene) deposits. It also is a reactivated fault along which 

had occurred at least two previous major episodes of 

faulting with a total pre-1959 displacement of as much 

as 60 feet. 

The south flank of that part of the broad basin of new 

subsidence within the West Yellowstone basin is a 

gently sloping . platform, broken by new low scarps 

(mostly less than 2 feet high) and small monoclines, 

along small east-trending reactivated faults. Previous 

displacements along these structures formed faults and 

abrupt monoclines with a maximum local structural 

relief of 50 feet in early Wisconsin surficial deposits, 

an·d progressively less in late Wisconsin and Recent 

materials. (The materials were studied by G. M. Richmond, and the structures by us.) Broad tilting and 

gentle warping also occurred during late Quaternary 

time. 

Most 1959 fault scarps in unconsolidated materials 

were nearly vertical, much steeper than the probable 

attitudes of the underlying bedrock faults, showing 

that fractures were refracted into steeper orientations 

as they approached the surface. 

Madison Valley south of the Madison River Canyon 

has been tnuch deformed by Quaternary tilting and subordinate faulting along structures ·which are oblique at 

high angles to the northwest-trending and generally 

older basin-and-range structures of Madison Valley and 

Madison Range, and which are continuous with the 

major east-trending structures of the tectonically very 

active Centennial Range and Centennial Valley. The 

late Quaternary warps and faults of the south part of 

vVest Yellowstone basin also have a dominant eastward 

trend, and other modern folds strike eastward from the 

basin to Gibbon River in Yellowstone N ationa1 Park. 

It appears to us that the northwest-trending Madison 

structures are being progressively modified and distorted as structures of the Centennial system are extended across them, and that the deformation accompanying the 1959 earthquake provided another 

increment in this modification. 

348. STRATIGRAPHY OF THE WILKINS PEAK MEMBER OF THE GREEN RIVER FORMATION, FIREHOLE 

BASIN QUADRANGLE, WYOMING 

By WILLIAM C. CULBERTSON, Denver, Colo. 

In the past few years the "Tilkins Peak member of 

the lacustrine Green River formation of Eocene age 

has been extensively explored for trona in the southern 

half of the Green River basin, but very little detailed 

information about the member has been published. 

During the summer of 1960, t.he author, assisted by 

H. W. Anderson, mapped the 'Vilkins Peak member 

in most of the Firehole Basin 15-minute quadrangle 

(fig. 348.1) and measured several sections. This work 

gives information on some prominent marker beds, 

their facies and color changes, and their correlation 

with units in the Diamond Alkali Co. No. 3 core hole, 

which is about 7 miles northwest of the quadrangle 

(fig. 348.2). . 

The Wilkins Peak member, which was named by 

Bradley (1959, p. 1072), is 875 to 1,050 feet thick in the 

'-. 
,-

.. 

\ 

SHORT PAPERS IN THE GEOLOGIC AN~ HYDROLOGIC SCIENiCES, ARTICLES 2 9 3-4 3 5 D-171 

0 10 MILES 

EXPLANATION 

D 

Area underll\in by 

Wilkins Peak member of Green River 

fonnatio.n . 

'-!., 

Columnar sections 

• 6 

Core-hole section 

WYOMING 

Jl'wu1m 648.1.-Index map showing Firehole Basin 15-minute 

qua<lrnngle nnd ndjucent nren, Sweetwater County, "ryo. 

See ~ectioM on Hgu re 348.2. 

Firehole Basin quadrangle and consists of phi.ty to 

fissile dolomitic marlstone, oil shale, claystone, limestone and dolomite; cross bedded siltstone and sandstone'; blocky mudstone; and several thin tuff beds. 

Calcareous algae in a few thin limestone beds and some 

poorly preserved plants are the only megafossils that 

were noted in the member. In the subsurface the member contains an unusual assemblage of saline minerals, 

chiefly shortite and trona (Milton and Fahey, 1960), 

that diminish in abundance eastward from the center 

of the Green River basin. On the outcrop the shortite 

crystals have been dissolved leaving molds, ~r they have 

been replaced to form calcite pseudomorphs. The top 

of the member is the base of the first brown fish-bearing 

oil-shale bed of the Laney shale member, and the base 

is placed at the top of thick laterally continuous oilshale beds of the Tipton shale member. 

SANDSTONE-SILTSTONE-MUDS.TONE UNITS \ 

Nine sandstone-siltstone-mudstone units, ranging in 

thickness frorri 4 to 85 feet (fig. 348.2), are persistent in 

varying degrees across the quadrangle. These are 

designated A to I, from oldest to youngest. On Sage 

Creek the units typically consist of interbedded yellow-

·ish-gray ( 5 Y7 /2) 1 arkosic very fine to fine grained sand.: 

stone, yellowish-gray ( 5Y7 /2) arkosic siltstone, grayish-olive (10Y4/2) argillaceous siltstone, and a minor 

runount of silty to nonsilty grayish-olive (10Y4/2) 

mudstone that weathers to a blocky rubble. Some units 

contain a few thin beds, 1 to 4 feet thick, of limestone, 

oil shale, or madstone. The sandstone and siltstone 

1 Color d~estgnntlons nccordtng to Rock Color Chart, National Rescnrch Council, 1948. 

are crossbedded· in long and very short sweeps, and 

channeling sandstone beds are common. The arkosic 

sandstone and siltstone beds generally weather to moderate olive-brown ( 5Y 4/4) ledges. Locally the units 

form slopes that appear dark green or olive-brown from 

a distance, in contrast to white-weathering beds that 

separate the units. . 

Northward the units become finer grained and 

thinner, and many are lighter in color. The A, B, 

and D units (fig. 348.2) are the most uniform and 

persistent of the lower eight units, and they are conspicuous ledge-formers throughout the quadrangle. 

The C E F G, and H units are less pe:rsistent; in ' ' ' . the vicinity of the Logan Draw and La.uder slide sections (fig. 348.2) they grade to mostly slope-forming 

silty and nonsilty mudstones that are pale olive 

(10Y6/2) to dusky yellow green (5GY5/~l), and that 

only locally contain a thin bed of ledge-forming crossbedded siltstone oi· sandstone. In the vVilkins Peak 

section farther northeast, the C, F, and H units underlie ' . covered slopes and consist mostly of ver.y pale-ohve 

(10Y7/2) mudstone (fig. 348.2). Units E and G each 

contain a small ledge of crossbedded sandstone or siltstone interbedded with the grayish-olive to pale-olive 

mudstone, but the units are not conspicuous. The thinning and the·change in color and !edging characteristics 

of theE through H units northward make: this part of 

the section appear similar from a distance to overlying 

white-weathering beds. 

In the upper part of the member, unit I is conspicuous 

everywhere as a dark-greenish band or ledge in the 

middle of a long white slope formed .on a shortite-bearing sequence of ma.rlstone, oil shale, and limestone. 

In the core description of Diamond Alkali Co. No. 3 

hole, the nine units are either silty or sandy mudstones 

(units B, D,. E, F, and G) or massive dark-green to 

gray mudstone or shale beds (units A, C, H, and I), 

and they are easily recognized. They can also be 

identified on the electric log of the well by their low 

resistivity. 

TUFF, LIMESTONE, AND MUDSTON'E BEDS 

At least six tuff beds in the vVilkins Peak member 

extend across the quadrangle (fig. 348.~~). The first 

(oldest) tuff is an analcitized bed 3 to 6 inches thick in 

the lower part of the member that weathers to dark 

yellowish orange ( 10YR6/6) slabs and bricks. The 

second and next higher tuff is very irregular in thickness ran {Tin()' from 3 to 12 inches,- and is everywhere ' 0 0 • h present in an oil shale and limestone interbed In t e 

lower part of unit A. The third and fourth tuffs in the 

upper part of the member are 2 to 20 in-ches thick and 

are 13 to 17 feet apart stratigraphically:; they are particularly conspicuous in the northwest part of the 
500 

1000 

Sage Creek 

Sees. 7 and. 8 

T.l5 N., R. 106 W. 

Firehole Canyon 

Sees. 19, 20, and 21 

T. 16 N., R. 106 W. and 

Sec. 24, T. 16 N., R. 107 W. 

3 

Lauder Slide logan Draw 

Sees. 19 and 30 Sees. 6, 7, and 17 

T. 17 S., R. 106 W. and T. 17 N., R. 106 W. and 

(a">E> Sec. 24, T. 17 S., R. 107 W. Sees. 11 and 12 

'Y T. 17 N., R. 107 W. W"lk. p k .r~ 1 ms ea 

'%• ber of Green River . Sees. 22, 26, and 27 

'• me~ I j6 mt~~es 10 T.18 N., R.106 W. 

~atiol) 

Diamond Alkali Co. No.3 core hole 

Sec. 8, T. 18 N., R. 108 W. 

(lithology adapted from core hole 

description by Diamond Alkali Co.) 

RESISTIVITY LUG 

8 

4in<;_h~ 

inches ~ 

13 inches 

2 .L mches 

T;pton 'hole membe' of G""'n R;ve, fo""'tion c. 

EXPLANATION 

Limestone 

~ 

B 

Tuff 

~ 

~ 

Mudstone 

~ 

~ 

Siltstone or silty mudstone 

Ed 

~ 

Sandstone 

D 

Marl stone, oil shale, dolomite, 

daystone, limestone, or covered 

FIGURE 348.2.-Columnar sections showing lithology and correlation of marker beds in the Wilkins Peak member, Firehole Basin quadrangle, and adjacent 

areas, Wyoming. Location of sections shown on figure 348.1. 

-< . ,, ,~- f (I .it . 

t:1 

I 

1-' 

'-1 

1:..:> 

c;:l 

·t".. 

0 

t:'4 

0 

c;:l 

~ t:'4 

U1 

q 

:::0 

< 

t".. 

~ 

:::0 

t".. 

U1 

t".. 

> 

:::0 

~ 

.... 

co 

0) 
1-

, 

v 

SHORT PAPERS IN THE GEOLOGJiC AND HYDROLOGIC SCIENiCES, ARTICLES 293-435 D-173 

qun.drangle. The fifth tuff is a layered tuff 2 to 3 inches 

thick, n.nd the sixth tuff is n.light-gr~ty massive tuff 3 to 

18 inches thick. The second, third, fourth, and fifth 

tuff beds are recognized in the core description of the 

Diamond Alkali Co. No. 3 hole, but identification of 

the first tuff is uncertain. 

At least two limestone beds can be easily correlated in 

the measured sections, but they are not recognized in the 

core hole (fig. 348.2). The upper is a bed 1 to 4 feet 

thick that forms a prominent bench at the top of unit 

}{in much of the area. The other forms a bench below 

unit G and is notable because it is 4 to 8 feet thick, contains less than 5 percent interbeds of claystone, and is 

slightly yellow on weathering. 

Two grayish-olive (10Y4/2) mudstone beds that are 

about 70 and 140 feet, respectively, above the base of the 

'iVilkins Peak member (fig. 348.2) are persistent marker 

beds throughout the quadra.ngle. In the core hole the 

lower p:trt of the member is much thinner than in the 

measured sections, so that the correlation of the two 

mudstone beds with beds in the core hole is uncertain. 

THREEFOLD SUBDIVISIONS OF THE WILKINS 

PEAK MEMBER 

Deardorff, l\1illic·e, and Textoris :l each subdivide the 

'Vilkins Peak member into three parts on the basis of a 

middle unit composed chiefly of green or brown siltst·one, sandstone, a.nd mudstone, but each recognizes a 

somewhat different middle unit. These middle units 

c:u1 be correlated with the nine marker units of the 

Firehole Canyon section (fig. 348.2) as shown on 

Hgure 348.3. 

2 Deardorff, D. L., 1959, Stratigraphy and oil Slhnles of the Green 

Hln!t' fonnnt:lon southwP8t of tlw Hock Spl'lngs uplift, Wyoming: 

:\fnster's thesis, Unlv. Wyoming, 98 p. 

Mllllce. Roy., 1959, Strntlgrnphy of the Green River formation In the 

!'Outhcnstern Bridger bnsln, Wyoming: Master's thesis, Unlv. Wyomln~, sn p. 

'J~o..xtorls, D. A ..• 1060, Stra tlgrupby of the Green River formation in 

the Bridger bnsln, Wy.omlng: Master's thesis., Ohio State Unlv., 107 p. 

Firehole 

Canyon 

section 

1""'""--~ 

D. l. Deardorff 

(1959, p. 93-95) 

Sage Creek section 

White shale beds 

Green siltstone tongue 

Greenish-gray 

shale beds 

Roy Millice 

(1959, p. 27 and 64) 

Firehole Can on section 

Upper unit 

Middle unit 

Lower unit 

D. A. Textoris 

(1960, pl. I) 

D.A.C. No. 3 core hole 

Upper unit 

Middle unit 

Lower unit 

letters A to I refer to units shown on columnar section, fi.gure 2; 

Theses cited in footnote in text 

FIGURE 348.3.-Probable correlation of subdivisions of Wilkins 

Peak member described in three unpublished Master's theses 

with the Firehole Canyon section. Letters A to I refer to 

units shown on columnar section, figure 348.2; theses cited in 

footnote 2. 

In the southern part of the area the middle unit of 

Deardorff is the 1110st distinctive, but in the northern 

part the middle unit of l\1illice is most easily recognized. 

The threefold subdivision of Textoris seems to be useful 

in the subsurface because of the distinctive electric log 

characteristics of each subdivision, although lateral 

changes such as the increase or decrease in number of 

trona beds may make electric log correlations locally 

uncertain. 

REF·ERENCES 

Bradley, W. H., 1959, Revision of stratigraphic nomenclature of 

Green River formation of ''r:\'Oming: Am. Assoc. Petroleum 

Geologists Bull., v. 43, no. 5, p. 1072-1075. 

Milton, Charles, and Fahey, J. J., 1960, Green River mineralogy-a historical account; ·in Wyoming Geol. Assoc. Guidebook ll"ith Ann. l!""i~ld Conf., Southwestern 'Vyoming ovel'-

t.hruSit area, l!)Gf>: p. ll"i!)-Hi2. 

349. CHILSON MEMBER OF THE LAKOTA FORMATION IN THE BLACK HILLS, SOUTH DAKOTA AND WYOMING 

By EnwiN V. PosT a.nd fii~NHY B1<:LL III, Denver, Colo., and Beltsville, l\1d. 

The stratigra.phic terminology of the Inyan l{ara 

group of Early Cretaceous age in the Black Hills of 

South Dakota and 'iVyoming hns recently been revised 

by IC l\1. 'V' aage ( 1959). Du.ring field work in the 

Black I-Iills in 1955 and 1956, Waage recognized a 

regional transgressive disconformity that separated 

rocks comprising the lower and upper parts of the 

Inyan l{ara group. This disconformable relation between the two parts of the Inyan l{ara group is similar 

to the relation between the two principal subdivisions 
D-174 GEOLOGICAL SURVEY RESEARCH 1 9 61 

recognized by Waage in equivalent rocks in the Colorado 

Front Range, in south-central Colorado, and in other 

parts of the western interior. 

Rocks above the transgressive disconformity make up 

the Fall River formation; they correspond closely with 

the Fall River as defined by Russell (1927, 1928). 

The rocks beneath the transgressive disconformity 

make up the Lakota formation, as redefined by Waage 

(1959). The Lakota formation includes as members 

rocks that formerly were placed in Darton's ( 1899) 

original Lakota sandstone as well as the Minnewaste 

limestone and. the Fuson formation. Much of Darton's 

Lakota, particularly in the southern Black Hills, has 

thus become merely an unnamed lower member in the 

revised Lakota formation, and has been referred to by 

Waage ( 1959·, p. 86) as .the "Lakota formation below 

[the] Minnewaste limestone member." 

CHILSON MEMBER 

The lower member is here named the Chilson member 

of the Lakota formation. The name is derived from. 

Chilson Canyon in the center of the Flint Hill quadrangle, where two principal subdivisions of the member 

are best developed coextensively. 

Subsequent to Waage's work, detailed geologic mapping by members of the U.S. Geological Survey on behalf of the Division of Raw Materials of the U.S. 

Atomic Energy Commission in 13 7~-minute quadrangles in the southern Black Hills has shown that the 

Chilson member is distinguishable beyond the limits of 

the Minnewaste limestone member, and that it consists 

of. two conspicuous fluvial sandstone bodies, each of 

which fingers latcra.Jly into flood-plain, lacustrine, or 

paludal facies. Each sandstone-mudstone complex is 

considered a subdivision of the Chilson member. These 

subdivisions are here informally designated unit 1 and 

unit 2. 

Because of the extreme lithologic variation within the 

Chilson member, no single type section is typical. 

Figure 349.1 shows representative stratigraphic sections 

of the Lakota formation, including the Chilson member, 

at three loca1ities in the southern Black Hills. The 

center section shows the rock units present in Chilson 

Canyon in the Flint Hill quadrangle, where both units 

1 ap.d 2 of the Chilson member are well developed. The 

left-hand section, at Red Canyon in the Edgemont NE 

quadrangle, is typical of areas in the southwestern 

Black Hills where unit 1 forms most of the Chilson 

member. The right-hand section, at FlagpoleMountain 

in the Cascade Springs quadrangle, is representative of 

the Chilson member in the southeastern Black Hills 

where it consists entirely of unit 2. 

The "Lakota formation below [the] Minnewaste 

limestone member" described by Waage ( 1959, p. 85-86, 

sec. 11) at the reference section of the Lakota formation 

in Fall River Canyon in the Hot Springs quadrangle 

consists entirely of various facies of unit 2 in the Chilson member, none of which can be directly correlated 

with beds shown in the sections on figure 349.1. 

Unit 1, the older, typically includes very fine grained 

well-sorted yellowish-gray sandstone in lenticular 

bodies separated by thin partings of carbonaceous siJtstone. Highly carbonaceous laminated siltstone and 

mudstone are interbedded with, or are laterally adjacent to, the sandstone. The unit ranges in thickness 

from zero to a maximum of about 400 feet; the greatest thickness is estimated to be present in the southcentral part of the Edgemont NE quadrangle. Vnit 1 

is believed to include the coal-bearing sequence of the 

Lakota described by Waage (1959, p. 40:-43) in the 

northern and western Black Hills. 

Unit 2 is the younger of the two Chilson units. It 

ov:erlaps unit 1 from the southeast, and is generally 

restricted to the southeastern Black Hills. Unit 2 is 

characterized by grayish-yellow or reddish-orange to 

reddish-brown very fine grained well-sorted rarely 

carbonaceous sandstone in lenticular bodies that are 

interbedded with and finger laterally into varicolored 

siltstone or claystone. The mudstone and sandstone · 

are calcareous at many places. Mudstones of unit 2 

are locally carbonaceous, particuiarly near their western 

boundary with unit 1. The thickness of unit 2 ranges 

from zero to 437 feet, and is greatest at Flagpole Mountain in the east-central ·part of the Cascade Springs 

quadrangle. 

The Chilson member of the Lakota formation rests 

on either the Morrison formation or the Unkpapa sandstone. Where sandstone forms the lowermost rock unit 

in the Lakota, the contact is clear cut. Mudstone of 

unit 1 can generally be distinguished by its content of 

carbonaceous material from the claystone in the Morrison or mudstone at the top of the Unkpapa. Locally, 

noncarbonaceous mudstone of unit 2 rests on mudstone 

of either the Morrison or U nkpapa, and at such places 

the contact must be chosen arbitrarily. 

Because of rapid facies changes in the Chilson member and the Fuson member, there has been much difficulty in mapping the contact between them. Most of 

this difficulty disappears, however, when the rocks 

are mapped in enough detail to show the distribution 

of the individual facies. Such mapping has shown 

that a distinctive reddish-brown sandstone .commonly 

forms the top of unit 2, both where the Minnewaste is 

present and for several miles beyond its limits. This 

sandstone has been used as a marker bed through much 

of the southern Black Hills. The greatest difficulty in 

mapping the contact between the Fuson and unit 2 of 
Stratigraphic section of the Lakota fort!lation 

Red Canyon, NW l/4 sec. 20, T. i S., R. 3 E. 

., 

::: = 

., 

..... 

·;§ 

Edgemont :'\E quadrangle 

(Measured by G. B. Gott and E. V. Post) 

Kfms~ Fall River formation: sandstone, yellu.vishormge, fine-g_l'ained 

San-dstmle;-fine-grained, white, ch1efry 

571. ledge forming, faintly crossbedded; 

lower 5 ft composed of lenses with 

intervening seams of carbonaceous 

siltstone 

Covered slope; one small outcrop of 

bro~mish-gray carbonaceous shale 10 ft above base 

Sandstone, very fine-grained, tabular, 

forms massive cliff, weathers light 

nn pinkish tan, iron-stained; carbona-

: ceous splotches, white clay grains 

. ~::::::: ~i::..:n-::u::.tpi"p""er'-5p aC'r'i'tt::-=-:::-:-:-::-Jt":::"-:c::-:-::::-:,..-:.-, Covered; probably gray carbonaceous sdty 

p::=Kicm1§20tf shale 

Ch_i lson 

\ 

-~-IP(> 

0? 

'0 .. 

~-~ 

~ ',J~ 

member 

\ 

\ 

Jm Morrison forma'tion: covered; probably 

green calcareous mudstone 

J.... 

----------- ·~ 

j 

Cooposi te stratigraphic section of the Lakota formation 

Chilson Canyon, sec. 32, T. 8 S., R. 4 E. 

., 

..... 

§ Kflst 

Flint Hill quadrangle 

(By Henry Bell and E. V. Post) 

Fall Ri,·er formation: laminated 

carbonaceous siltstone 

Sandstone, yellowish-or;.,ge, fine-grained 

to conglomeratic, crossbedded 

Claystone, silty, gray to mottled reddishbro~n, commonly contains a thin gray 

limestone-pebble conglomerate and limestone concretions in lo,.er 2 ft. 

Local! y r6!X)ved by erosion and replaced 

by overlying sandstone 

-:-, 

Stratigraphic section of the Lakota formation 

Flagpole Mountain, sec. 33, T. 8 S., R. 5 E. 

and sec. 3, T. · 9 S., R. 5 E. Cascade Springs quadrangle 

(Measured by E. V. Post) 

-, 

Fall River fomation: rubble of yellowish-, 

Dis- Kfms~ c:> orange fine-grained silicified sandstone 

-conformity [~~~~~~~-r-~~-.~~~~~~----l Fuson ~~::=Kifm::::::::: 60 Cove:ed; prob:mly underlain by gray to member var1egated silty claystone 

Minnewaste 

limestone 

··=t':'Nt11.=- :_.J\121 ~~ton-o, gray, sandy1 _ in 2-f.~ b~s 

.'·~~H~.EHitd •51 s~~:~:~~ ~~~~sh-~:_ .... ge, _fine-grained. 

.-=T<Jc~== 22 · Mldstone, light-gray, locally calcareous; : -:- ::_- . -.. top 2 ft reddish-bro-.n to yellowish-

' member .:(t~~9.~:z?:£~-;;-. orange siltstone 

-:- -----:- \.- Sandstone, yellowish-.orange, fine-grained, i 

~=~!:~c=. 2t : crossbedded, __ :0~~rs with mudstone. ~v~ 

:~~~~~~~~~~@ 

§~~~~!~~~g460 

!·~ IU!H U:i<:\fi;iiii!!]•4o ,::1 

Jm 

Sandstone, grayish-yellow, fine-grained, 

composed of many crossbedded lenses 

separated by thin beds of siltstone or 

mudstone. Coumonly includes a 5 ft 

thick reddish-bro..-. smdstone at top, 

and is overlain to east by Minnewaste 

limestone mtmber 

~lldstone, pale greenish-gray, locally 

calcareous, contains ostracods; 

includes some thin sandstone beds, md 

fingers eastward into S2 sandstone 

Sandstone, yellowish-gray, fine-grained, 

locally carbonaceous; composed of many 

crossbedded lenses separated by thin 

beds of dark-gray carbonaceous siltstone and mudstone 

Morrison formation: pale olive-gray 

calcareous mudstone 

\ 

\ 

\ 

\ 

Chilson 

member 

\ 

\ 

0 

... 

"' t 

~ 

~-

~ 

~~Ifii~~ :~~~~~~~~~~~·~~ 

h~l~-~.ri!~~ 38 

Mudstone, I argel y covered; upper part 

yellowish-gray to gray calcareous 

mudstone; sparsely carbonaceous clay 

shale at base; includes a thin sandstone 

Sandstone, pale yellowish-orange, very 

fine-grained, scattered small patches 

of white to greenish-gray interstitial 

clay; lower part contains large lerises 

of crossbedded s~dstone, upper part 

tam! ar bedded 

Largely cov~red; probably greenish-gray 

silty claystone containing thin 

tabul ar-hedded light-gray sandstone 

\.%~~\ ltw~fu~~~~J\(t 60 sra:~~ :~~~~?!~~]\;:;~- J 

Ju 

Unkpapa sands tone: pale-pink finegrained ~mdstone that weathers to 

rounded somewhar. caven1uu~ cli.ff:S. Probably not more than 50 ft thick 

FIGURE 349.1.-Representative stratigraphic sections of the Lakota formation in the southern Black Hills. Symbols in columns shown on figure 349.2. 

~ 0 

~ 

8 

"d 

> "d 

t>:l 

~ 

r:/1 

z 

~ t>:l 

0 

t>:l 

0 

t"4 

0 

0 

d 

~ t::l 

~ t::l 

~ 

0 

t"4 

0 

0 

~-

() 

r.J2 

0 

~ 

t>:l 

~ ~r:/1 

> 

~ 

~ 

~ t>:l 

rJl 

1...:> 

c:o 

~ 

I 

~ 

~ 

~ 

t? 

....... 

~ 
D-176 GEOLOGICAL SURVEY RESEARCH 1 9 61 

the Chilson member has been encountered beyond the 

limits of both the red sandstone marker bed and the 

Minnewaste limestone member. Detailed mapping 

generally allows the geologist to locate the contact between the uppermost sandstone in unit 2 and an interval of distinctive limestone concretions and calcareous 

conglomerate ~ear the base of the Fuson. Rocks of 

unit 1 can generally be distinguished from the overlying Fuson rocks both by the absence of carbonaceous 

material and the presence of variegated mudstone and 

conglomeratic sandstone in the Fuson. 

MINNEW ASTE LIMESTONE MEMBER 

The Minnewaste limestone member has been mapped 

with little difficulty. It ranges in composition from 

rather clean dense pinkish-gray limestone to calcareous 

sandstone; the typical rock is sandy limestone. The 

Minnewaste ranges in thickness from zero to a maximum of 80 feet; the greatest thickness was noted in a 

gully draining into the east side of Tepee Creek in 

the southeastern part of the Cascade Springs quadrangle. The Minnewaste described in the reference section of the redefined Lakota formation by 'Vaage ( 1959, 

p. 85, sec. 11) is representative of the unit, and it is 

here suggested that this be taken as the reference section of the Minnewaste limestone member. 

FUSON MEMBER 

Waage (1959, p. 29) has suggested that "Darton's 

Fuson is the key to the difficulties that have arisen in 

attempts to map his threefold subdivision in different 

parts of the Black Hills," and has stated (p. 32) that 

the Fuson " * * * lacks definite upper and lower contacts and is too variable in rock type * * * to permit 

consistent id~ntification on the basis of its own lithic 

content." Because of this, ~Taage (1959, p. 33) recommended discarding the name "Fuson," or at best, 

restricting its use to the area in the southeastern Black 

Hills where the Minnewaste limestone member is 

present. 

By ·recognizing the regional transgressive disconformity as the contact between the Fa.Il River and 

Lakota formations, Waage ( 1959) has in effect defined 

the top of the Fuson. The rocks above and below this 

disconformity differ from place to place; laminated 

carbonaceous siltstone at the base. of the Fall Hiver 

formation commonly rests either on Fuson mudstone or, 

in places, on conglomeratic channel sandstone. The 

contact is readily mappable where thick channel sandstone of the Fall River formation rests on Fuson mudstone, but is difficult to map where such sandstone in 

the Fall River rests on similar sandstone in the Fuson 

member. 

Several characteristic lithologies have been recognized in the Fuson member. Variegated claystone and 

siltstone is perhaps the most widespread and characteristic Fuson rock type, particularly in the southern and 

northern Black Hills. White, speckled with red, 

massive argillaceous fine-grained sandstone commonly 

exists in the middle of the member, and a thin brightgreen clayey sandstone. is found at many localities in 

the middle of the member. Channel sandstone that is 

locally conglomeratic 0{lfs3 on figure 349.2) comprises much of the lower Fuson along the western side 

of the. Black Hills, and crossbedded conglomeratic 

sandstone (Klfs4 on figure 349.2) also fills a channel 

scoured from the top of the Fuson part or all the way 

through the mudstone and massive argillaceous sandstone facies in the southern Black Hills. Common in 

the lower. 15 feet of the Fuson in the southern Black 

Hills is a thin-bedded ripple-bedded reddish- or yellowish-orange ·fine-grained loc.ally calcareous sandstone 

that has streaks and smalll~nses of clay parallel to the 

bedding; the clay weathers out giving the rock a 

characteristic pitted surface. A thin calcareous conglomerate and concretions of limestone or barite occur 

locally in the lower 5 feet of the member. Polished 

well-rounded pebbles of pink quartzite, quartz, and 

chert are diagnostic of the Fuson; they weather abundantly out 9f the mudstone beds of the member 

throughout the Black Hills area. 

Ostracodes found in the calcareous conglomerate near 

the base of the Fuson member were described by I. G. 

Soh:t;,J. (written communication, 1955) as differing from 

those. in other collections of the Lakota formation in 

that they include a large smooth genus not typical of 

Lower Cretaceous rocks. Thus, it appears that the 

Fuson and Chilson members may be distinguished by 

paleontologic as well as lithologic evidence. 

The base. of the Fuson member is in contact with 

either thg top of the Minnewaste limestone member, the 

top of the several facies of the Chilson member, or, in 

parts of the. Black Hills, with the top of the Morrison 

forll_lation and possibly the top of the Unkpapa sandstone. The greatest difficulty in locating the base of 

the Fuson member has been encountered in the relatively small are.a where the Fuson rests on unit 2 of 

the Chilson member, but detailed mapping of the various facies along this contact has resulted in satisfactory 

location of the contact. 

The type locality of the Fuson member at Fuson 

Canyon in the southeastern Black Hills is not satisfactory for several reasons. The base of the member is 

not exposed, the Minnewaste limestone member is 

absent in that immediate area, and the Fuson there 

consists dominantly of sandstone and siltstone. The 

. f 
,-

SHORT PAPERS IN THE GEOLOGI•C AND HYDROLOGIC SCIENtCES, ARTICLES 293-435 D-177 

following stratigraphic section l1as the :Minnewaste 

limestone member underlain by the red sandstone 

marker bed of the .Chilson member as a base, and it 

includes more of the mudstone so typical of the Fuson 

in much of the. Black Hills. It is presented as a reference section for the Fuson member of the Lakota 

formation in the southern Black Hills. The variability 

of the Fuson may be demonstrated by compar~ng this 

section :with that at Fuson Canyon (Waage, 1959, p. 84, 

sec. 10), with the Fuson member at Waage's re.ference 

section of the Lakota formation in Fall River Canyon 

south of I-Iot Springs, S. Dak. ('Vaage, 1959, p. 85, sec. 

11), and with a section measured in Red Canyon north 

of Edgemont, S.Dak. (fig. 349.1). 

nnfermu;e 8tra,Uymphlr; Neat-ion. of the P·n80n nwm1Je·r of the 

Da./i:ota. format·ion on. en8t 1Jank of Cheyenne 1~·ive·r, SW% 

NlVY.\, seo. :2, ~/'. 9 S., n. 1 .E., Casande S1wimgs q1/.aflrangle, 

Ji'all River 0fJ'II'II.t'/J, S. Dak. 

[Measured by E. V. Post and D. W. Lane] 

}.,all River formation (in par't) : Feet 

Siltstone, dark-gray, carbonaceous, laminated; becomes 

sandy and more massive at tOP--------------------- 30 

Sandstone, yellowish-gray, fine-grained, locally micaceous ; contains white clay grains in streaks along 

bedding; bedding wavy; weathers cavernous _______ _ 

Lakota forma1tion : 

}.,uson member : 

Sandstone, white to pink, splotched with red, mediumto tine-grained, friable; abundant interstitial white 

clay in streaks parallel to bedding ; broad lowangle crossbeds; becomes clayey at top __________ _ 

Claystone, variegated green to dark reddish-brown; 

silty att base------------------------------------

Mudstone, yellow, jarositic, limonitic, gypsiferous; in 

12 

38. 

10 

pa~t a boxwork of selenite with little mudstone____ 1 

Claystone, dark-gray to greenish-gray; largely clean, 

some carbonaceous ; hackly fracture ; includes limestone concretions 6 to 8 inches thick by 1 to 2 feet 

in diameter ait base_____________________________ 26 

Conglomernte, medium-gray ; limestone and white 

silty claystone pebbles in a calcareous sandstone 

tnatriX----------------------------------------- 1.5 

Claystone, gray to olive-gray_______________________ 5. 5 

Sandstone, light yellowish-gray, fine-grained, calcareous, tightly cemented----------------------- 3 

Total thickness of Fuson member______________ 85. 0 

Miunewnste limestone member: 

I.Jimestone, pinkish-gray, dense ; conltains streaks of 

coarsely crystalline calcite_______________________ 2 

Lakot.-'l formation-Con tin ned 

Chilson member (in part) : 

Unit2: 

Sandstone, moderate reddish-brown, fine-grained, 

moderately well-cemented_____________________ 5 

Sandstone, pinkish- to yellowish-orange, finegrained to very fine grained, modeootely wellcemented; sparkles because of secondary silica 

overgrowths on quartz grains; color banded with 

red iron-oxide bands along laminae of abundant 

white clay grains---------------------·-------- 30 

REGIONAL CORRELATION 

The mapping and stratigraphic studies of the Inyan 

l{ara group in the Black Hills carried out by the Geological Survey from 1952 to 1957 resulted in part in the 

correlation of rock unit$ as shown by Mapel and Gott 

( 1959). Work done during 1958 and 1959 has resulted 

in further definition of the relations among these various rock units in the southern Black IIills. Figure 

349.2, which is a reduced and revised version of the cross 

section published by Ma·pel and Gott ( 19!59), shows the 

relations among the Fuson, Minnewaste, and Chilson 

members of the Lakota formation as presently under-· 

stood. 

The most significant change in this section was made 

in the area between the Edgemont NE quadrangle and 

the Wyoming-South Dakota boundary, where it was 

recognized that the conglomeratic sandstone labeled· 

Klfs3 on figure 349.2 (and S2 by Mapel and Gott, 1959) 

is, in fact, a sandstone in the Fuson member, and therefore younger than rocks of the Chilson member. This 

has resulted in assigning practically alll the conglomeratic sandstone of the Inyan l{ara group to the Fuson 

member of the Lakota, formation. 

The various sequences of the Lakota formation described by 'V aage ( 1959, p. 35-46) can be matched very 

closely with the formally named members of the Lakota. His northern and eastet~n sequences, as well as 

the upper part of the southern sequence:, are equivalent 

to the Fuson member, and his coal-bearing sequence 

and the lower part of the southern sequence are equivalent to the Chilson member. 'Vaage (1959, p. 48) 

recognized this correlation in stating, 

If the correlations suggested here are correct, beds Darton 

called Lakota and Fuson (in part) in the northwestern Black 

Hills are equivalent only to beds he called Fuson in the southeastern Black Hills. To state it another way, using Darton's 

classification, there is no Lakota in the northwestern Black 

Hills-it is all Fuson. 
.-, 

D-178 

/nyon 

Koro 

Creek 

I Crook I Weston 

County . County 

Klfm Klfm 

GEOLOGICAL SURVEY RESEARCH 1 9 61 

Newcastle Edgemont Flint Hill Cascade Hot 

I WYOMING I NE 1 quad jSpringsiSprings SOUTH DAKOTA quad quod quod SE 

Klfm FALL RIVER FORMATION Kits Klts 4 

Fuson member 

Klfs 4 sandstone, locally conglomeratic Klfm ,'variegated mudstone 

Klfs,wnite massive sandstone 

Klfs 3 ,sandstone, locally conglomeratic 

@J<'if!ig 

Minnewoste limestone member 

Gray sandy limestone 

Chilson memberKics2, grayish-yellow to reddish-brown finegrained sandstone 

Klcsm2 , interbedded sandstone and. mudstone 

Klcc 1 , variegated claystone 

Klcst 1 , carbonaceous siltstone 

Klcs 1 , yellowish-gray locally carbonaceous fine-grained sandstone 

Klcm 1 , carbonaceous siltstone, mudstone, 

or shale 

z 

0 

~en 

<(:::> 

~0 

a::w 

0(.) 

U..<[ 

<(1- .,_w 

oct: 

~(.) 

<(-

_J 

Kl s4 Klfm Klfs4 z 

Q 

1-

<( 

~ 

a:: 

0 

u.. 

~ 0 

~ 

<( 

_J 

1 coECa::::j5E::;;:::::==ioC:::=====IE;0:::::===~20 Miles 

Vertical exaggeration approximately 210X 

}.,IGURE 349.2.-Diagrammatic restored cross section of the Lakota and adjacent formations in the southwestern Black 

Hills showing the relations among the Fuson, Minnewaste limestone, and Chilson members of the Lakota formation. 

The line that marks the top of the Chilson member 

on figure 349.2 has been emphasized. By following it 

northwestward, one can clearly see that the Chilson 

member pinches out in the vicinity of Inyan Kara 

Creek and that the Lakota formation northwest of that 

point consists entirely of the Fuson member. 

REFERENCES 

Darton, N. H., 1899, Jurassic formations of the Black Hills of 

South Dakota: Geol. Soc. America Bull., v. 10, p. 383-396~ 

Mapel, W. J., and Gott, G. B., 1959, Diagrammatic restored 

section of the Inyan Kara group, Morrison formation, and 

Unkpapa sandstone on the western side of the Black Hills, 

Wyoming and South Dakota·: U.S. ~eol. Survey Mineral 

Inv. Field Studies Map MF-218. 

Russell, W. L., 1927, The origin of the sandstone dikes of· the 

Black Hills region: Am. Jour. Sci., 5th ser., v. 14, p. 402-

408. 

--- 1928, The origin of artesian pressure: Econ. Geology, 

v.23,no.2,p.132-157. 

Waage, K. M., 1959, Stratigraphy of the Inyan Kara group in 

the Black Hills: U.S. Geol. Survey Bull. 1081-B, p. 11-90 . 

~ 

r-
SHORT PAPERS I:r:T THE GEOLOGI•C AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-179 

350. ARTESIAN WATER IN THE SPIRITWOOD BURIED VALLEY COMPLEX, NORTH DAKOTA 

By C. J. HuxEL, Jr., Grand Forks, N.Dak. 

Work llone in ooopemtion with the North Dakota State Geological Survey and the North Dakota State Water 

Conservation Commission 

Thick bodies of saturated sand and gravel were discovered in 1958 during reconnaissance test drilling near 

the eastern boundary of Stutsman County, N. Dak. 

Subsequent drilling has indicated that these sand and 

gravel deposits are part of a large buried valley system 

cut into the Cretaceous Pierre shale. The buried valley 

system is referred to as the Spiritwood buried valley 

complex, and its location and relation to other buried 

valley systems are shown on figure 350.1. 

Cross sections (figs. 350.2 and 350.3) show that the 

Spiritwood buried valley complex consists of several 

distinct valleys. In section B-B' a deep trenchlike 

inner vu.lley filled with clay is shown incised into a 

wider and more gently sloping outer valley. In section 

A-A' two separate and distinct valleys are shown side 

by side. A similar relation is illustrated in section 

D-D', although the valleys are of different depths and 

are more widely separated than those shown in section 

A-A'. It is inferred from existing well data that a 

major tributary enters th~ Spiritwood buried valley 

complex at a point about 4 miles south of section 0-0' 

and 3 miles west of the county line (fig. 350.2). 

Significant thicknesses of sand and grave] have be(m 

found only in the westernmost valley shown by section 

A.-A', the outer and more gently sloping valley shown 

by section B -B', and the incompletely defined valley 

shown by section 0 -0' (fig. 350.3). Water-bearing 

sands and gravels in these valleys are referred to as the 

10 20 30 40 MILES 

Ji'IGURE 850.1.-Map showing physiographic provinces of North Dakota (modified from Simpson, 1929) and relation of the 

Spiritwood buried valley complex to other buried valley systems in the region. Rectangle indicates area shown in 

figure 350.2. 
D-180 GEOLOGICAL SURVEY RESEARCH 1 9 61 

Spiritwood aquifer and are considered to be glaciofluvial in origin. The Spiritwood aquifer reaches a 

maximum thickness of at least 115 feet and is found between altitudes of 1,150 and 1,370 feet. Thick bodies 

of silt and clay in the inner valley of section B -B' (test 

hole 1594, fig. 350.3 ). and the eastern valley of section 

D-D' may be either preglacial or glaciofluvial in origin. 

T. 

139 

N. 

T. 

138 

N. 

T. 

137 

R. 62 W. R. 61 W. R. 60 w·. 

N. ~~--------~------L-~--------------L-~~ 

0 Y.> 1 4 MILES 

EXPLANATION 

231~ 0 

Well in the Spiritwood aquifer 

Upper number indicates depth, in feet, of 

well; lower number indicates depth, in 

feet, to water 

~ 

Well for which specific conductance 

was determined 

+ 

Well for which chemical analysis of 

water is available 

----- Boundaries of buried valley 

1750. 

Test hole 

Number is designation of hole 

A A' 

Location of geologic section 

Dashed lines show offset holes 

Intermittent lake 

F'IGURE 350.2.-Map showing location of wells and test-holes 

in the Spiritwood buried valley complex. 

The range in depth and width of the several valleys 

within the Spiritwood buried valley complex is apparent in the test-hole sections. The size of the Spiritwood buried valley complex suggests that it may have 

been a major segment of the preglacial-drainage system in North Dakota. The ancient Cheyenne system 

may have flowed. north into Dickey County along the 

trend of a moraine (Flint, 1955, p. 148) which is correlated ·with one of the inner members of the Antelope 

morainic system (fig. 350.1). According to Hard 

(1929, p. 28) this moraine might ma.rk the trm~d of a 

buried valley. Upham (1894, p. 244; 1895, p. 107) 

thought that the Cheyenne system extended from the 

end of the moraine northeastward to the present Red 

River channel and then northward into Hudson Bay. 

It is possible, however, that the ancient Cheyenne system continued straight north from the end of the inner 

Antelope moraine, and that the Spiritwood buried valley complex is a segment of that system. Such a course 

is marked by depressed areas and areas of interior 

drainage from LaMoure (fig. 350.1) to the line of section D-D' (fig. 350.2). The Spiritwood buried valley 

complex can be traced on the basis of well inventory 

data from the line of section A-A' northeastward into 

southern Griggs Cmmty, a distance of more than 20 

miles. At this point the Spiritwood complex is only 

6 miles southeast of the southeastern extension of the 

buried Heimdal Valley (fig. 350.1). 

All existing wells in Stutsman County have been inventoried and the locations of those penetrating the 

Spiritwood aquifer are shown on figure 350.2. Depth 

to water in these wells ranges from above land surface 

in a flowing well in T. 138 N., R. 62 W., to 70 feet below 

land surface in a well in T. 140 N., R. 62 W. 

Chemical analyses were made on water samples from 

3 wells and specific conductance determinations in the 

field were made on water from 7 other wells. The total 

dissolved solids were calculated from the specific conductance determinations. Of the 10 wells for which 

data are available, 8 yielded water in which the total 

dissolved solids were between 500 and 800 ppm (parts 

per million). The other 2 wells, in theSE'% T. 138 N., 

R. 62 W., are 220 and 171 feet deep and were found to 

have. total dissolved-solid contents of 1,343 ppm and 

1,158 ppm, respectively. 

Aquifer tests are needed to determine the groundwater yield of the Spiritwood aquifer; however, its-large 

areal extent and thickness, the coarseness of its gravels, 

and its high degree of saturation indicate that it is 

potentially productive. 

,·-
SHORT PAPERS IN THE GEOLOGI'C AND HYDROLOGIC SCIENiCES, ARTICLES 293-435 D-181 

1724 1731 j~ 1500' 

-1400' 

-1300' 

Pierre shale 

-1200' 

EXPLANATION 1500' B 

1595 

1364 

D 

Till 1400' 

• 1300' 

Clay Pierre shale 

- 1200' 

Sii!Y clay 1100' Pierre shale 

1111 

Silty to sandy clay 1000' 

c 1346 C' 15oo· 

1597 • 1500' 1348 

Sandy clay 

1400' 1400' 

S.and 1300' 1300' 

Pierre shale 

- 1200' Gravel 1200' 

D D D ,1500' 1500' 1601 

Lignite concentration 1739 1740 

1400' 1400' 

Test hole endin~ in glacial drift 1300' 1300' 

_a 1200' 1200' 

Test hole complete~ to bedrock 

1100' 1100' 

0 If.! 2 MILES 

FIGURE 350.3.-Cross sections in the Spiritwood buried valley complex. 

REFERENCES 

~"'lint, R. F., 1955, Pleistocene geology of eastern South Dakota: 

U.S. Geol. Survey Prof. Paper 262, 173 p. 

Hard, H. A., 1929, Geology and water resources of the Edgeley 

and LaMoure quadrangles, North Dakota : U.S. Geol. Survey Bull. 801, 90 p. 

Simpson, H. S., 1929, Geology and ground-water resources of 

North Dakota: U.S. Geol. Survey Water-Supply Paver 598, 

.312 p. 

Upham, Warren, 1894, Tertiary and early Quaternary base 

leveling in Minnesota, Manitoba, and northwestward: Am. 

Geologist, v. 14, p. 235-246. 

---1895, The glacial Lal<e Agassiz: U.S. Geol. Survey Mon. 

25, 658 p. 
D-182 GEOLOGICAL SURVEY RESEARCH 1 9 6 1 

351. A BURIED VALLEY NORTHWEST OF MANHATTAN, KANSAS 

By HENRY V. BEcK, Manhattan, Kans. 

Work done in cooperation with ·the State Geological Survey of Kansas 

North and north west of Manhattan, Kans., is a buried 

valley about 2 miles wide. The altitudes of the ground 

surface in this area ranges from about 1,040 feet in the 

east to about 1,180 feet in the west. The valley was 

reported, but not described, by Todd (1918, p. 197) and 

Mudge ( 1955, p. 273). The buried valley is Y -shaped 

with the base of the Y pointing to the northeast in 

the direction of former flow (fig. 351.1). The valley is 

widest where the two branches join and it narrows toward the northeast. Here the valley is confined between high bluffs composed of Permian rocks. 

Logs of test holes indicate that the gravel deposits 

in the basal part of the buried valley are overlain by 

reddish-brown silt and clay ranging in thickness from 

about 7 to about 80 feet. The gravels in the southwestern tributary are composed of limestone and chert 

fragments of. local origin. The deposits in the southeastern branch are composed principally of arkosic 

gravel, indicating a westerly source. 

Furthermore, thl.s area contains some gravel deposits 

of glacial origin. Glacial boulders in these deposits 

probably were derived from colluvial wash from deposits of glacial drift on Bluemont Hill. 

The deposits in the buried valley are typical of those 

found in terraces of Kansan and Illinoian age that 

are east of the junction of the Kansas and Blue Rivers. 

Davis and Carlson (1952) applied the names Menoken 

to terrace deposits of Kansan age, Buck Creek to terrace deposits of Illinoian age, and Newman to terrace 

deposits of Wisconsin age. The principal differences 

in the terrace deposits of Kansan and Illinoian age are 

the lithologic character of the gravel and the topographic position. Generally Menoken deposits have 

a higher percentage of glacially derived material than 

the Buck Creek. In the area extending eastward from 

Manhattan to a point near Lawrence, the bedrock surface beneath the Menoken terrace ranges from 45 to 70 

feet above the bedrock surface beneath the Buck Creek 

terrace. The interval between the two surfaces is less 

in the western part of the area. The bedrock sur~ace 

beneath the Buck Creek terrace is about.15 feet below 

the surface of the Newman terrace. 

During a part of the Pleistocene, the ancestral Kansas River flowed northward through the buried valley 

by way of the southeastern branch and the outlet to 

the northeast. The ancestral Wildcat Creek joined 

this stream at a point about 2 miles north and a little 

west of Manhattan. The ancestral Wildcat Creek 

abandoned a segment of its channel in the buried valley 

and established its present course no later than early 

Illinoian time. The evidence for dating this change 

in course is based on terrace deposits along the west 

· side of the present Wildcat Creek valley in the SW% 

sec. 13, T. 10 S., R. 7 E., (fig. 351.1), which have been 

identified as Illinoian in age. They are equivalent to 

the Buck Creek terrace of Davis and Carlson (1952) 

and Beck (1959). Gravel deposits in the basal part 

of this terrace are principally of local origin, but also 

contain some glacial gravel that probably was derived 

from glacial drift on the upland area west of the valley. 

In the buried valley the gravel deposits are an important source of ground water. The yields of wells are 

dependent on the thickness of gravel at any particular 

locality. 

Bedrock in the buried valley adjacent to Blue River 

lies at altitudes ranging from 1,002 to 1,025 feet, and 

in· the southeastern branch altitudes range from 1,020 

to 1,050 feet (fig. 351.2). In the southwestern branch, 

altitudes are generally above 1,060 feet. The contours 

indicate that the streams flowed northward and northeastward and preclude the possibility that the ancestral 

Blue River flowed southward through the valley. The 

southwestern branch had the steepest gradient, which 

is typical of a tributary stream draining qa limestone 

a!ld shale terrane. The deepest part of the southeastern branch is along the east side of the valley, which 

may indicate a second period of downcutting in this 

area. · The earlier period of cutting reached base level 

at altitudes near 1,050 feet, and the second entrenchment reached base level near 1,020 feet. 

· Glacial deposits on Bluemont Hill and on the hill 

south and west of Manhattan are evidence that the 

channel was blocked by ice during the Kansan glacial 

period. The cutting of the valley between Bluemont 

Hill and !(-Hill may have begun at this time, but the 

southeastern branch of the buried valley was again occu-

\. 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENiCES, ~RTICLES 2 9 3-4 3 6 

N 

r 

Alluvium 

k~A~·;<1 Newman terrace of 

Wisconsin age 

ll~l~l~B.s;Il~l Buck Creek terrace of 

Illinoian age 

~ Bedrock 

Contact 

Dashed where approximately located 

46-3 

0 1035 

Depth of testhole-gravel 

thickness. Slant number indicates bedrock 

altitude 

D-183 

>-

0::: 

c( 

z 

0::: 

w 

1-

c( 

:J 

0 

?___ _____ _,1 MILE 

FIGURE 351.1.-Goologic map of Manhattan, Kans., and vicinity. 
D-184 

0 1 MILE 

~---------------~ 

GEOLOGICAL SURVEY RESEARCH 1 9 6 1 

. R.7 E. R.8 E. 

EXPLANATION 

Alluvium 

~;::-(::::96:r:·~·.::l Newman terrace of 

Wisconsin age 

~~ ~~~~~ ~~:9: ~ ~: ~~ ~:~~~~~ Buck Creek terrace of 

Illinoian age 

>-

0:: 

c( 

z 

0:: 

w 

1-

c( 

~ 

0 

Bedrock 

---/060-

Bedrock contours Contour interval 10 feet 

Trend of buried channels 

I050o 

Drill hole Number refers to elevation 

of bedrock surface 

FIGURE 351.2.-Bedrock contour map of buried valley. 

\ 
SHORT PAPERS IN THE. GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-185 

pied and deepened by the ancestral Kansas River in 

late J{ansan time and probably in early Illinoian time. 

Illinoian terrace deposits, in the SW1,4 sec. 13, T. 

10 S., R. 7 E., are evidence that the ancestral Wildcat 

Creek occupied its present course no later than early 

Illinoinn time. By early Wisconsin time, the nncestral 

l{nnsns River had abnndoned the buried valley and 

hnd brenched the area between Bluemont Hill and 

K-Rill. Illinoian deposits are absent in the valley between these hills. The valley is narrow here, however, 

and if such deposits were deposited it is probable that 

they hnve been removed by floods of the Kansas River. 

REFERENCES 

Beck, H. V., 1959, Geology and ground water, Kansas River 

valley between Wamego and Topeka vicinity : Kansas Geol. 

Survey Bull. 135, 88 p. 

Davis, S. N., and Carlson, W. A., 1952, Geology and groundwater resources of the Kansas River valley between Lawrence and Topeka, Kansas: Kansas Geol. Survey Bull. 96, 

pt. 5, p. 201-276. 

Mudge, M. R., 1955, Early Pleistocene geomorphic history ·of 

Wabaunsee, southeastern Riley, and southern Pottawatomie 

Counties, Kansas: Kansas Acad. Sci. Trans., v. 58, no. 2, 

p. 271-281. 

Todd, J. E., 1918, History of Kaw Lake: Kansas Acad. Sci. 

Trans., v. 28, p. 187-199. 

352. STRATIGRAPHY OF LOWER AND MIDDLE PAR'fS OF THE PIERRE SHALE, NORTHERN GrREAT PLAINS 

By JAMES R. GILL and WILLIAM A. CoBBAN, Denver, Colo. 

The Pierre shale of Late Cretaceous age was deposited in a broad epicontinental sea that covered the 

Great Plains States and contiguous areas to the west 

and extended north into Cannda. The eastern limit of 

the sea is not well known. The Pierre is being studied 

to determine the chemical, mineralogic, and sedimentltry changes that take place in fine-grnined rocks across 

a basin of marine deposition (Tourtelot, Schultz, and 

Gill, 1960}. Strntigraphic investigations conducted 

concurrently with geochemical and mineralogic studies 

by H. A. Tourtelot and L. G. Schultz cover about twothirds of the basin of deposition in the northern Great 

Plains (fig. 352.1}. 

Rocks deposited along the eastern shoreline of the 

busin have been removed by post-Cretaceous erosion 

but much of the broad eastern stable shelf and eastern 

slope areas remain (fig. 352.1). These areas, far removed from the dominant westward source of the sediments, were the site of slow to moderate deposition and, 

in general, contain a distinctive suite of fine-grained 

shale and marlstone. The trough of the basin was the 

site of more rapid deposition and contains coarser 

grained rocks. There is a pronounced westward increase in coarser grained rocks across the trough of the 

basin and the western slope area, and an interfingering 

of marine beds with brackish-wate:r: and nonmarine deposits on a narrow western shelf. 

The three units described here (figs. 352.2B and 

352.3 A and B) represent the lower and middle parts of 

the Pierre shale of South Dakota and equivalent rocks 

described by various names in adjacent States (fig. 

604493 0-6L-13 

352.4 and table 352.1). These units reflect three distinct phases in the depositional history of the Upper 

Cretaceous rocks of the region. The first depositional 

phase is one of regression (fig. 352.1A}, herein referred 

to as the Eagle regression ·(R-2 regression of Weimer, 

1960) ; the second phase is one of transgression (fig. 

352.1B}, the Claggett transgression (T-3 transgression of Weimer, 1960); and, the third phase is one of 

regression (fig. 352.10) called the Jiudith River regression (R-3 regression of Weimer, 1960). 

EAGLE REGRESSION 

Rocks between the Niobrara formation and the base 

of beds equivalent to the 'Claggett shale-roughly 

equivalent to the Eagle sandstone of Montana (fig.· 

352.2B and table 352.1 )-represent the. initial regressive 

phase of deposition of the Pierre shale (figs. 352.2B and 

352.4). The depositional history of the shelf area east 

of the zero thickness· line is obscure. Some st~atigraphers believe that the area was undergoing erosion at 

the time (Reeside, 1957; LeRoy and Schieltz, 1958), 

Stratigraphic and paleontologic evidence now strongly 

suggest that beds equivalent to the Eagle sandstone i~­

terfinger with and grade into calcareous beds of the 

Niobrara formation in the eastern shelf area (fig. 

352.4). 

The western part of the stable eastern shelf and the 

eastern slope area contain dominantly noncalcareous 

deposits of gray bentonitic claystone, a few thin silty 

layers, and abundant red-weatherin1~ thin ferruginous 

layers and concretions (Gammon ·fe.rruginous member 
D-186 GEOLOGICAL SURVEY RESEARCH 1 9 61 

A. Eagle regression C. Judith River regression 

r---

1 I 

I "'"' 

I 

_J 

B. Claggett transgression 

Paleogeographic data outside .area studied 

is modified from Reeside, 1957 

0 500 MILES 

EXPLANATION 

Permanent Land Area 

Island or areas of nondeposition 

Erosion 

Nonmarine deposits 

~~v :v ~~ C_lastic rocks of volcanic origin 

Stable shelf area 

Slope area 

.. 

Trough area 

FIGURE 352.1.-Paleogeographic maps for the lower and middle parts of the Pierre shale and equivalent rocks. 

\ 
--

107° 1030 99°--- "'"-

I '\ \ 

49°r---r--rz-r---r-----r \'' 

~ . ' ' \ NORTH DAKOTA 

\ 

\ 

_...<:::::::.-----~\ IV ~ 

I 

I ', __ , 

NEBRASKA / Q.'flj ~o..'ru [l)~ 

~ 

'Oru' 

Ct-

~'lJ 

~'1> <; 

...,_ r-~"""-l ' - ,, 

,, \- _.,...._ --- *~ \ 

o{J \ 

__ _: _______ l 

\ 

\ 

f{ VI 

\ 

' KANSAS 4 

v 

47 

39 

I 

I 

1-----, 

- ' 

I 

\----

B 

99° 

--,---

\ 

~ --1 

Sussex sandstone member \ 

of Cody shale, and equivalents 

~ ~ 

I'd 

~ t;l 

" Ul 

z 

~ t;l 

C) 

t;l 

0 

t" 

0 

C) 

(:) 

~ tj 

~ tj 

::d 

0 

t" 

0 

C) 

B 

0 

t;l 

~ 

~ 

SJl 

~'~ --\ 

tent of Eagle sandstone, Shan-\. 

non sandstone member of Cody 

shale, and Groat sandstone bed 1 

> 

" ~ 

~ Extent of Virge\\e sandstone mem=' 

ber and equivalent sandstones \ 

not shown 

Ul 

~ 

c.o 

~ 

! 

~ 

~ 

01 I 

1 

L/1'-lv-'~) I '[_ sp 23" MILES 

- I I - I ____..L-----'\ ----~----l'- ~ I 

FioUBE 352.2.-Index map and tblckness map of the Eagle regressional phase of the Pierre shale. A, Location of restored seettons. Roman nUJDerals 

refer to correlation chart (table 352.1). B, Thickness maP of rocks between top of Niobrara formation and the base of bedS equi~alent to the 

Claggett shale. Arrows shOW probable direction of seiliJDent transpOrt. 

A 

t( 

~ 

~ 

....:r 

--
41" 

Extent of 

~ radioactive black 1 

~~'-'" ~ --organ;;;;;;;t'•---I 

Extent of unnamed sandstone ~ 

I 

l ~ 

41" 

0 50 100 MILES I 

I 

39 

I 

A B 

gg• 

-r.-

1 

I 

I 

I 

I 

I 

I 

I _L_ 

I 

I~ 

0 _L_ 

~-=--==---~--=- \ 

c,ow C<eek membe< and~ _j_calcareous shales of the~ Gregory member of the 1 

shale I _L_ 

_L_ // 

___L.._// 

-:-/// ~ I 

I 

~ ----1 

t of sandstones of the Judith 1 

River formation and the Hygiene I 

and Parkma-tone members l 

Nonmarine beds in the upper part I 

of the Parkman sandstone member 1 

FIGURE 352.3.-Thickness maps of the Claggett transgressional and the Judith River regressional phase of the Pierre shale. .A, Rocks equivalent to the 

Claggett shale. B, Rocks equivalent to the Judith River formation. Arrows show probable direction of sediment transport. 

~· ' /:' 

t:1 

I .,_. 

00 

00 

C) 

t?:l 

0 

t-4 

0 

C) 

~ 

Q 

> t-4 

~ ::tl 

< t?:l 

~ 

::tl 

t?:l 

rJl 

t?:l 

> ::tl 

@ 

....... 

(C 

(:1) 

....... 
Eastern 

A Montana 

Northern Black 

Hills 

r 

Missouri River 

Valley A' 

'~:::::.~~' ~"::: . ~ .:::_: . : : ;.:;. r:- ,;~~~" •• ..• ·; ·. . ..... < -~---·· 

C~~ettsha~ =~~~~----········--· ~ x ~~t~~i~if~:~~~~i~i:i~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~1 X X ~ 

I ~ : ll..!. X~ ~iobrara 

formation 

..... 

z: 

e r----- :g Virgelle ... __ . . . __ 

~ sandstone -- · · · --

~ member 

~ 

·············· <( :I: 

en Gammon 

...., ~ I ferrugmous . w member 

0::: 

-y 

'/ 

:/' ~ 

formation 

Sou~hern Po_wder -.L._ - _J..- ~~~t:;~ B R1ver Basm ? B' 

·Non.rTiari.ne .. i:>e"ds~~ THEEL~~~~~::::: sharon springs 

·································· ' 

2 

~ !m~l!~l~---·_· _____ - ;I ,~:~~~ · tc:: 

~ 

----···j ... _...., c:: 

c:: 

UJ 

0::: 

--L.:... 

/ 

I 

Rusty zone of 

G;lbe.rt (1896) 1-.. . . ... _..., / 

-;;_ 

Sharon 

Springs 

member 

? ---.-l--

formation FEET 

500 

400 

300 

200 

100 50 100 MILES 

EXPLANATION 

1~---L~ Calcareous shale and marlstone 

B 

Persistent beds of bentonite 

Radioactive organic-rich 

~ 

~ black shale 

D 

Dark gray shale and claystone 

bd 

~ 

Siltstone 

tmm:wmm 

Sandstone 

FIGURE 352.4.-Diagrammatic sections showing correlation of lower and middle parts of the Pierre shale· and equivalent rocks in the northern Great Plains. 

Location of sections shown on figure 352.2.4. 

~ 0 

~ 

"'d 

> "'d 

trl 

~ 

UJ 

z 

~ trl 

0 

trl 

0 

t"4 

0 

0 

c 

~ t:=' 

~ t:=' 

~ 

0 

t"4 

8 

~ 

~ trl 

~ 

~ UJ 

> 

~ ~ trl 

r.tl 

to:) 

co 

~ 

I 

~ 

~ 

01 

? 

.... 

~ 
D-190 GEOLOGICAL SURVEY RESEARCH 1 9 61 

TABLE 352.1.-Correlation of lower and middle parts of the Pierre shale ana equivalent rocks, northern Great Plains 

[Roman numerals refer to areas shown on figure 352.A,· dot shows index fossil collected) 

Index I II III IV v VI 

fossils Missouri Valley of Colorado east of Eastern Montana Powder River Basin Black Hills South Dakota Front Range Western Kansas 

:E Crow Creek member u. 

• Baculites scotti • • • • 

Judith 

(marine 

River 

in this 

formation 

area) ~~ • Parkman sandstone Unnamed silty shale Hygiene member 

sandstone ! ~~ member member 

I • B. gregvryensis (/) 

I.IJ • • Gregory member • :E ? • B. n.sp "F" ..!.I • • I=' • I=' I=' I=' • B. n. sp "E" .1..1 • 0: 

• Mitten black shale 0: 0: 

• Rusty zone of Gilbert 0: <( <( <( <( 

e:, e:, e:, e:, • B. n. sp "0" ..1../ • • member • • (1896) Claggett shale I.IJ I.IJ Sharon Springs I.IJ I.IJ Sharon Springs 

• ...J • ...J ...J 

• ...J • • B. asperiformis !='~· ~ <( member <( <( member ::r Sharon .Springs ::r ::r Sharon Springs ::r 0: (/) 

• B. maclearni <( (/) • member (/) • member (/) 

e:, I.IJ I.IJ I.IJ I.IJ 

•B. obtusus • • 0: • 0: 0: • 0: 

I.IJ 0: 0: 0: 7 0: • ? :c!~··· I.IJ I.IJ I.IJ I.IJ - a: a: a: a: ~ Sussex sandstone member I I ~ 

I • >- ~--· ... ··· Groat sandstone bed . F. § Shan~on sandstone mbr 

Eagle sandstone 

• Scaphite.~ ? u ~sandstone 

f l hippocrepis ' !"""-: • Gammon 

I 

Virgelle sandstone member 

ferruginous member 

.....!./ Zapp and Cobban, 1960 

of Pierre shale in the Black Hills region, fig. 352.4). 

The trough of the basin was the si~ of rapid deposition in which great thicknesses of silty and sandy beds, 

bentonitic claystone, and persistent beds of bentonite 

accumulated, The Sussex, Shannon, Groat, Virgelle, 

and other sandstones occur at several horizons (figs. 

352.2B and 352.4). These beds thicken and become 

coarser grained ·to the west. Oil has been produced 

commercially from some of these sandstones in the 

southwest part of the Powder River basin, and gas is 

produced from similar beds in easterp. Montana. 

CLAGGETT TRANSGRESSION 

Rocks equivalent to the Claggett shale of Montana 

(fig. 352.4 and table 352.1) represent a transgression of 

the Pierre sea. (fig. 352.3A). Volcanism at the start of 

this phase resulted in widespread ashfalls that are preserved as persistent beds of bentonite at the base of the · 

black shale sequence throughout the Dakotas, Montana, 

Wyoming, and western Nebraska. 

D~posits of the stable eastern shelf area are thin, 

consisting of black organic-rich radioactive shale and 

thin beds of bentonite characteristic of the Sharon 

Springs member of the Pierre shale (fig. 352.4). These 

rocks contain 'distinctive ammonite faunas (table 352.1) 

and have easily identified electric and gamma-ray 

curves that provide a reliable time-stratigraphic datum 

throughout the ·area. The distinctive black shale and 

bentonite sequence of the shelf area extends westward 

across the eastern slope area into about the center of 

? ? ? 

the basin where the organic-rich black shale loses its 

identity because of dilution with detritus from the 

western source area. The bentonite beds thicken toward 

the source area and retain their identity over large 

areas. 

Deposits of the stable eastern slope area accumulated 

more rapidly than those of the eastern shelf; in addition to bentonite and organic-rich bhtek shale, the deposits contain black flaky shale characteristic of t.he 

Claggett shale. The thickness of these transgressive deposits increases gradually across the western Dakotas. 

and eastern Montana (fig. 352.3A). Western Nebraska, 

north-central Colorado, and southeastern Wyoming 

were the site of rapid deposition resulting in thick accumulations of black shale and silty and sandy beds in 

the -bottom of the trough (figs. 352.3A and 352.4). 

Sandy deposits in this stratigraphic interval are 

thought to . indicate an isolated local source area m 

south-central Wyoming. 

JUDIT·H RIVER REGRESSION 

Rocks equivalent to the Judith River formation (fig. 

352.4 and table 352.1) represent the second regressive 

depositional phase of the Pierre sh~e. Nonmarine 

rocks were deposited along the eastward retreating 

shoreline in western Montana and Wyoming (figs. 

352.10 and 352.3B) and are represented in the trough 

portion of this area by regressive beds of marine 

sandstone. 

The restricted eastern shelf area received thin ac-

\ 

,. 
I, 

SHORT PAPERS IN THE. GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-191 

cumulations of claystone, calcareous shale, and thin 

beds of silty marlstone. N oncalcareous shale and silty 

shale were deposited in the eastern slope area. The 

trough of the basin contains relatively thick deposits of 

silty shale, siltstone, and sandstone. In the northern 

part of the area, the thickness of the unit and the distribution of sandstone deposits indicate that the sediments were being transported eastward across Montana 

and northeastward. across North Dakota (fig. 352.3B). 

The arcuate pattern formed by the 300- and 400-foot 

isopach lines may have been the result of ocean currents 

moving in a clockwise direction. 

Nonmarine deposits in the upper part of the Parkman sandstone (figs 352.3B and 352.4) show that the 

western shoreline had moved eastward into the Powder 

River basin of east-central '~ryoming near the close of 

this phase of deposition. 

Natural gas is produced in eastern Montana from 

sandstones in the Judith River formation and oil is produced from the Parkman sandstone member of the 

Mesaverde formation in eastern Wyoming and from 

the Hygiene sandstone 1nember of the Pierre along the 

Front Range .in Colorado. 

REFERENCES 

Gilbert, G. K., 1896, The underground water of the Arkansas 

Valley in eastern Colorado: U.S. Geol. Survey 17th Ann. 

Rept., pt. 2, p. 551-601. 

LeRoy, L. W., and Schieltz, N. C., 1958, Niobrara-Pierre 

boundary along Front Range, Colorado : Am. Ass~c. 

Petroleum Geologists Bull., v. 42, no. 10, p. 2444-2464. 

Reeside, J. B., Jr:., 1957, Paleoecology· of the Cretaceous seas of 

the Western Interior of the United Statt~s. in Treatise on 

marine ecology and paleoecology, v. 2 : Greol. Soc. America 

Mem. 67, p. 505-542. 

Tourtelot, H. A., Schultz, L. G., and Gill, J. R., 1960, .Strati-

~raphic variations in mineralogy and chemical composition 

of the Pierre shale in South Dakota and adjacent parts 

of North Dakota, Nebraska, Wyoming, and Montana, in 

Short papers in the geological sciences: U.S. Geol. Survey 

Prof. Paper 400-B, p. B447-B452. 

Weimer, R. J., 1960, Upper Cretaceous stratigraphy, Rocky 

Mountain area: Am. Assoc. Petroleum Geologist Bull., v. 

44, no.l, p. 1-20. 

Zapp, A. D., and Cobban, W. A., 1960, Some Late Cretaceous 

strand lines in northwestern Colorado and northeastern 

Utah, in Short papers in the geological sciences: U. S. Geol. 

Survey Prof. Paper 400--B, p. B246-B249. 

GEOLOGY AND HYDROLOGY OF ALASKA AND HAWAII 

353. ANALYSES OF GAS AND WATER FROM TWO MINERAL SPRINGS IN THE COPPER RIVER BASIN, 

ALASKA 

By D9NALD R. NrcHOLS and LYNN A. YEHLE, Washington, D.C. 

Two gas .and mineralized-water springs, previously 

reported by the authors (1961, p. 1076), were sampled 

during the summer of 1960. These springs, here 

termed the Copper Center and Tazlina mineral springs, 

issue from small mounds and thus .may be classed as 

incipient mud volcanoes. Several other smaller 

springs, n.1so presumably mineralized, have been seen 

from the air, but were not visited. All of the springs 

are in the southeastern Copper River Basin (fig. 353.1), 

and appear to be associated with mud volcanoes that 

have been divided into two general groups based on 

geographic distribution and chemical and physical 

characteristics. The Drum group (Shrub, Upper 

l{lawasi, and Lower IGawasi mud volcanoes) lies east 

of the Copper River and has the largest cones, 150 

to 310 feet high; its springs are characterized by ear·. 

bon dioxide gas a.nd warm sodium bicarbonate and 

sodium chloride waters. The Tolsona group (Nickel 

Creek, Shepard, Tolsona No. 1, and Tolsona No. 2. mud 

volcanoes) lies west of the Copper River and has cones 

25 to 60 feet high; all but the inactiv'e Shepard mud 

volcano have springs that discharge methane gas and 

cool sodium chloride and calcium chloride water. . 

East of the Copper River, thick ghwial, lacustrine, 

and fluvial deposits mantle andesitic lavas of Tertiary 

to Recent age. West of the Copper River, marine sedi· 

mentary rocks of Cretaceous age, and semiconsolidated 

sandstone, conglomerate, and a few thin lignitic beds of 

Tertiary age, are overlain by Pleistocene deposits 

(Miller and others, 1959, p. 52, pl. 3). 

DESCRIPTION OF THE SPRINGS 

The Copper Center mineral spring is 2y2 miles N. 

20° E. of Copper Center (fig. 353.1). It consists of 
D-192 GEOLOGICAL SURVEY RESEARCH 19 61 

62°00' 

GLENN 

~=E.,.-XP"'""'L_A __ N_A~T~IO....,N~--, 

® 

Mud volcano 

X 

Mineral spring 

Nickel Creek 

@ 

XHudson 

5 

®shrub 

0 5 10 15 MILES 

WRANGLE 

• Mount 

Drum 

MOUNTAINS 

FIGURE 353.1.-Location of principal mud volcanoes and mineral springs, Copper River Basin, Alaska. 

two vents, each 1¥2 inches wide, and a single pool 5 

to 8 feet in diameter and 2 feet deep. The pool and 

vents lie on the eastern edge of a barren, almost imper-

. ceptible mQund, the base of which is about 75 feet in 

diameter and about 1 foot below the nearby ground 

surface. The mound consists largely of pebbly clayey 

silt to a depth of at least 31h feet. The bottom of the 

pool, however, is covered by medium to coarse sand. 

Coarse gravel, which lines the drainage channel from 

the spring, and twigs and sand in the pool are coated 

by an iridescent bluish-purple precipitate. 

When observed, water in the pool was clear green 

·and had a temperature of 63°F, 12° less than the air 

temperature but 15° to 25° more than ground-water 

temperature. Water from the pool discharged into a 

small stream at a rate of about 9 gpm, but sank into 

the stream bed within 300 yards. Discharge from the 

vents. was insignificant. A dry, grass-covered drainage 

way, 50 to 500 feed wide, that extends southwestward 

from-the spring to a gully incised in the bluffs of the 

Copper River suggests that discharge of water from 

the pools was much greater in the past. Gas bubbled 

intermittently from several places in the pool and from· 

the two small vents. 

The Tazlina mineral spring is in a clearing on a low 

terrace north of the Tazlina River, about 21h miles east 

of Tolsona Creek. In this approximate area, Theodore 

Chapin, in 1914 (unpublished data), found a "circular 

area 15 feet across [with] over 50 mud volcanoes * * * 

[and with] mounds 4 to 5 feet high." The Tazlina 

spring, which may be the same as Chapin's mud 

volcanoes, presently consists of 4 pools 3 to 5 feet in 

diameter on a single grass-covered mound 3 to 4 feet 

high and 250 feet in diameter. The mound is composed 

of dark-gray clayey silt and fine sand. Gas bubbled 

intermittently from 3 of the 5 vents in the largest pool 

at the mound crest (fig. 353.2), but activity was very 

sporadic in the other 3 pools on the northeast slope. of 

the mound. The water seeps into grass-covered 

marshes bordering the pools; the rate of ·discharge 

could not be measured. Gray, silt-laden water in the 

pools had a salty taste and a temperature of 40° F, 

close to that of the ground water but 35 o lower than air 

temperature· at the time, measured. 

WATER AND GAS ANALYSES 

Waters from the Copper Center and Tazlina mineral 

springs (table 353.1) are similar to waters of the 

Tolsona group of mud volcanoes (Nichols and Yehle, 

1961, table 3) ; the principal difference is that the 

average of total dissolved solids of the T~lsona group 

is much lower than that of the Copper Center mineral 

spring and much higher than that of the Tazlina 

mineral spring. Waters from the Tolsona group also 

have an appreciably higher iron content. Both the 

spring and mud volcano waters are relatively low in 

bicarbonate and high in chloride and calcium in contrast to waters of the Drum group. 

r 

{ 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-193 

FmuuE 353.2.-Gas bubbling from 2 of 5 vents in pool at crest 

of Tazlina mineral spring. 

TABLE 353.1.-Analyses of water and ratios of chemical constituents in water from Copper Center and Tazlina mineral 

springs 

[Analyses by U.S. Geological Survey, Palmer, Alaska.] 

Constituent (ppm): 

SiOz __ _ - -- -·· _ -- _ ---- -- __ Fe _________ _____ ______ _ 

Ca ___ _________ _____ ___ _ 

~g ___ ___________ ____ _ _ 

Na ___ _________________ _ 

!{ __ ___________________ _ 

~n ___ __ __________ ____ _ 

H co3 ___ ______________ _ 

804- - - ----------- - -----

Cl- --- ----------~--- F __ _______________ ____ _ 

P04 __ _ - _---- - - - _- _- ___ _ 

Total dissolved solids 

(calculated) ________ _ 

Hardness as CaC03 ----- ----- N on-ca.rbonate _____________ _ 

Specific conductance ________ _ Density _____ _______ ________ _ 

pH ___ ____________________ _ _ 

Ratio: 

Ca/Na ____ ________ _____ _ 

~g/Ca ________________ _ 

K/Na __ _______________ _ 

HC03/CL ------------- 804/CL _____ ___ ______ _ _ 

F/Cl ____ ______________ _ 

Mineral spring 

Copper Center 

(Sample 6129 col- lected Aug. 7, 1960) 

24 

.0 

3, 060 

24 

5, 960 

55 

. 04 

124 

4. 0 

14, 400 

1.7 

. 05 

23, 600 

7, 730 

7, 630 

36, 400 

1. 017 

8. 0 

. 5134 

. 0078 

. 0092 

. 0086 

. 0003 

. 0001 

Tazlina (Sample 6131 collected 

Aug. 8, 1960) 

24 

. 03 

909 

48 

1, 170 

11 

. 25 

216 

3. 5 

3,400 

. 3 

--------------

5, 670 

2,470 

2, 290 

9,800 

-------------- 7. 3 

. 7769 

. 0528 

. 0094 

. 0635 

. 0103 

. 0009 

TABLE 353.2- Analyses of gas from Copper Center and Tazlina 

mineral springs, and Tolsona No. 1 mud volcano 

[Mass spectrometer analyses by, and used with permission of, Helium Activity Laboratory, U.S. Bureau of Mines, Amarillo, T ex.; Tr.=traee, less tban 0.05 

percent] 

Mineral springs 

-------.----1 ~o~';?~~l!~; Copper Cen- Tazlina (Sample ter (Sample (Sample Y -o.287<, colN-Q.224d, col- N-Q.229, col- lected Aug. 29, 

lected Aug. 7, lected Aug. 8, 1960) 1960) 1960) 

Component (percent): 

Methane ______ . ______ _ 44. 6 58. 2 63. 4 

Ethane _____________ __ 0 0 Tr. 

Propane _______ _______ 1 1 1 

n-butane _____________ 0 0 Tr. 

i-butane __ ____________ 0 0 Tr. 

n-pentane _____ _____ __ 0 0 0 

i-pentane ______ ______ _ 0 0 0 

Cyclo-pentane ___ ___ __ Tr. 0 Tr. 

Hexanes plus ________ _ Tr. 0 Tr. 

Nitrogen _____________ 55. 0 40. 4 35. 9 

Oxygen ______________ Tr. 1 1 

Argon ________________ 1 2 1 

Helium ____________ ___ Tr. 1 1 

Hydrogen ____________ 0 1 0 

Hydrogen sulfide __ ____ 0 0 0 

Carbon dioxide ________ 1 9 2 

Total ______________ 99. 9+ 100. 1 99. 9+ 

f:)ulfur odor_ _____________ ~-- --- ----- ----- - - - ----------

Calculated total Btu _______ 454 592 645 

.Analyses of gas emanating from the Copper Center 

and Tazlina mineral springs and an analysis of gas 

from the Tolson a No. 1 mud volcano are presented in 

table 353.2. These analyses show a high methane and 

nitrogen content and closely resemble analyses of 

Tolsona group gases (Nichols and Yehle, 1961, table 

2) . This contrasts with the predominantly carbon 

dioxide gas emanating from the Drum group. 

The Copper Center and Tazlina mineral springs are 

included in the Tolsona group of mud volcanoes because 

of the composition of their water, and especially of 

their gas. Comparison of the ratios of chemical constituents of the spring water with median ratios of 

chemical constituents of other waters of different types 

as reported by White (1960, p. B452) shows no striking 

similarities, and the source of the water issuing from the 

springs and mud volcanoes remains uncertain. However, the close similarity of gas from springs and mud 

volcanoes of the Tolsona group suggests that all have a 

common source, perhaps from buried Cenozoic marsh or 

coal deposits, or from porous nonpetroliferous beds of 

pre-Tertiary (Cretaceous?) age. 
D-194 GEOLOGICAL SURVEY RESEARCH 19 61 

REFERENCES 

Miller, D. J., Payne, T. G., and Gryc, George, 1959, Geology of 

possible petroleum provinces in Alaska: U.S. Geol. Survey 

Bull. 1094, 132 p. 

Nichols, D. R., and Yehle, L. A., 1961, Mud volcanoes in the 

Copper River Basin, Alaska, in Geology of the Arctic : 

Toronto, Canada, Univ. of Toronto Press, p. 1063-1087. 

White, D. E., 1960, Summary of chemical characteristics of 

some waters of deep origin, in Short papers in the geological 

sciences: U.S. Geol. Survey Prof. Paper 400-B, p. B452-

B454. 

354. THRUST FAULTS IN THE SOUTHERN LISBURNE HILLS, NORTHWEST ALASKA 

By RussELL H. CAMPBELL, Menlo Park, Calif. 

Work done in cooperation with the U.S. Atomic Ene_rgy Oommi88ion 

The structure of the southern Lisburne Hills, Alaska, 

is dominated by north-trending imbricate thrust faults 

along which rocks of the Lisburne group of Mississippian age have been thrust eastward over Lisburne and 

younger strata. The· zone of thrust faulting extends 

from the Chukchi Sea northward· to Cape Lisburne 

where it again passes beneath the waters of the Arctic 

Ocean (Collier, 1906; Dutro, Sable, and Bowsher, 

written communication, 1958). The northerly structural trends of the Lisburne Hills are in sharp contrast to the general easterly structural trends of the 

Brooks Range and Arctic Foothills provinces. 

The rocks of the area are exclusively sedimentary, 

probably all marine, and most are well stratified. They 

range in age from Devonian( n (Collier, 1906, p. 16, 

17) ·to Cretaceous and crop out in parallel northeast- to 

north-trending bands in which the rocks are generally 

successively younger from west to east (fig. 354.1). No 

angular unconformities have been observed, but a disconformity probably occurs at the top of the Lisburne 

group, and disconformities may separate all the 

younger units. · 

The overthrust sheets are composed principally of 

relatively competent limestone and dolomite beds of 

the Lisburne group, but they locally include infolded 

segments of older and younger rocks. Silty mudstone 

of Mississippian age underlies the Lisburne group conformably at a few places, but at most places the contact is a thrust fault, beneath which the less competent 

mudstone has been plastically deformed. Relatively 

incompetent mudstone and sandstone of Cretaceous and 

Cretaceous or Jurassic ages have been intensely crumpled and broken by high-angle faults chiefly along bedding planes and axial planes of folds; they give a gross 

impression of plastic deformation. 

The combined dip slip of the thrust faults is ~stimated to be a minimum of 5 miles to the east. The 

photograph (fig .. 354.2) illustrates some details of the 

thrust faulting at a site of particularly good exposure. 

Beds of the Lisburne group that overlie the Triassic 

rocks along the Agate Rock thrust belong about 5,000 

feet. stratigraphically below the top of the Triassic 

strata. The basal contact of the Lisburne group is exposed in the sheet above the Eebrulikgorruk thrust. 

Rocks at this horizon belong about 2,000 feet below beds 

of the Lisburne group that immediately underlie the 

fault surface. 

A regional dip to the east or southeast is indicated by 

the exposure of progressively younger units from west 

to east, even though westerly dips are common at surface exposures of the strata. As shown by structure 

section A-A' (fig. 354.1), Mesozoic and Paleozoic strata 

25,000 to 30,000 feet thick are present in the eastern 

part of the area, but have been eroded off the western 

part. In addition to the stratigraphic evidence, gravity 

data show a generally gradual decrease in simple Bouguer anomalies from northwest to southeast in the area 

shown by figure 354.1 (Barnes and Allen, 1961, p. 80-

86). All the exposed sedimentary rocks have approximately the same density, so the relatively smooth 

gravity gradient is interpreted to reflect a gradual eastward thickening of the sedimentary rocks overlying a 

dense layer that is either relatively smoothly sloping 

or so deeply buried that its irregularities are not 

expressed. 

The earliest reasonable date for the thrusting in the 

Lisburne Hills is late Early Cretaceous inasmuch as 

rocks of that age are involved in the deformation. 

Some folding of the thrust planes occurred as higher 

sheets rode over lower ones. Additional relatively 
SHORT PAPERS IN THE GEOLOGJIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 

68' 

15' 

68 

00' 

A 10,000 

17• 

X ;o ~ "' 0 

~ ~ 

~ " ;:;; 

" ~ ~ 

" it 

APPROXIMATE MEAN 

DECLINATION , 1960 

q?-~ ~~· 

ARCTIC OCEAN 

5 0 5 

LEVEL SEA l=~~--====~~~~~~~~~~~~ I 

10,000 

20,000 

10,000 

20,000 Hypothetical section 2 

10 15 MILES 

EXPLANATION 

Sedimentary 

~ deposits, 

undivided 

U<su;/ 

Sedimentary rocks, 

undivided 

~ KJs~ j 

Sedimentary rocks, 

undivided 

1~6 1 Shublik and Siksikpuk 

formations 

Local.ly inrludes infolded 

Lower Cretaceous or Jurrrssic 

roch 

!Mi~ l Lisburne group, 

undivided 

I1M;i)tJ 

Sedimentary rocks 

"except Lisburne group 

Sedimentar ~ y rocks, 

undivided 

Contact Geology, east of 166o 12' mend ian ./Jculted wMre approzimatelw 

by R. H. Campbell and others, located 

1958-1960; west of 166'12' 

mendtan by G. W. Moore, 1960 

A' 

High angle fault 

• • o • •• 

Thrust fault 

Sawteeth on upper plate 

a-Ahviknuk fault 

b-Eebrulikgorruk fault 

c-AgateRock fault 

d-Saleekvik fault 

e-Angmarok fatdt 

ARBITRARY DATUM 

25,000~----------------------------------------------------------~ ~~ 

D-195 

FIGURE 354.1.-Generalized geologic map and sections of the southern Lisburne Hills. Hypothetical sections illustrate 

suggested development of the thrust faults by gravity gliding. 
D-196 GEOLOGICAL SURVEY RESEARCH 1961 

NW SE 

FIGURE 354.2.-Photograph of sea cliffs at Agate Rock showing thrust faults. Ms, Mississippian rocks except Lisburne 

group;· Mlu, Lisburne group of Mississippian age; P, Permian rocks; li, Triassic rocks; KJsu, Jurassic or Cretaceous 

rocks. Altitude of cliff top is 625 feet. 

gentle folding also probably occurred after the thrusting ceased, and may have been associated with the 

subsidence of the area around and west of Point Hope. 

This may account for general westward dips of the 

thrust planes at their western exposures. 

The association of eastward overthrusting with an 

eastward regional dip suggests that the thrusting took 

place by gravity gliding as illustrated by the hypothetical sections (fig. 354.1). Thrusting may have been 

triggered by the same deforming stresses that resulted 

in upwarp in the vicinity of Point Hope relative to the 

area to the east and southeast. Relatively competent 

rocks of the Lisburne group tended to move as coherent 

sheets, chiefly along numerous weakly bonded bedding 

planes at and near its base. The mudstone of the underlying unit, particularly if water saturated, could 

have served as a lubricated, possibly buoyant zone along 

which the overlying coherent sheets could slide. No 

low-angle faults have been found in the rocks of Jurassic 

and Cretaceous age in this area, except small discontinuous ones in locally gently dipping strata. Indeed, it 

is difficult to visualize how a thrust fault could be maintained as a single flat-lying surface within such incompetent beds. It seems more likely that ahead of the 

moving sheets of competent limestone these younger 

rocks were intricately crumpled and the thrust faults 

split up along bedding planes and axial planes of folds 

into many faults of small displacement. Frontal piles 

of such crumpled strat~ may have prevented further 

movement on lower thrust planes such as the Angmarok 

and Saleekvik faults ( e and d, fig. 354.1) so that later 

movement took place at higher levels, res'ulting in the 

imbrication of thrust sheets. 

REFERENCES 

Barnes, D. F., and Allen, R. V., 1961, Preliminary results of 

gravity measurements between Kotzebue and Point Hope, 

· Alaska, in Kachadoorian, Reuben, and others, Geologic investigations in support of Project Chariot, Phase III, in 

the vicinity of Cape Thompson, northwestern Alaska-preliminary report: U.S. Geol. Survey open-file report, p. 80-86. 

Collier, A. J., 1906, Geology and coal resources of the Cape Lisburne region, Alaska: U.S. Geol. Survey Bull. 278, 54 p. 
SHORT PAPERS IN THE GEOLOGllC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-197 

355. PHYSIOGRAPHIC PROCESSES OF SEDGE MEADOW POOL FORMATION ON LATOUCHE ISLAND, ALASKA 

By HANSFORD T. SHACKLETI'E, Georgetown, Ky. 

Latouche Island is one of the outermost islands of 

Prince William Sound, lying about 100 miles southwest 

of the mainland port of Valdez. The climate here is a 

mild, wet coastal type; the mean annual precipitation is 

.184 inches, and the average snowfall is about 153 inches. 

The mean annual temperature is approximately 42° F; 

the absolute maximum is 82° F, and the absolute minim urn is 1 o F. The bedrock is predominately hard, compact, dull-gray graywacke and interbedded medium- to 

dark-gray slate (Stejer, 1956, p. 110-111). Unconsolidated surficial deposits are described by Stejer (p. 111) 

as follows: 

Unconsolidated deposits of Quaternary age overlie much of the 

bedrock. Glacial deposits mantle large parts of the valley floor, 

alluvium occurs in patches along the streams, and talus forms 

thick blankets along the lower slopes of the high ridge that 

borders the valley. 

The weathered upper layers of the glacial deposits contain sufficient fine silt and clay to form a zone of mineral 

soil almost impervious to vadose water. The area is 

thus without effective underground drainage, and most 

of the heavy rainfall and snow melt water is removed 

as surface runoff (George 0. Gates, oral communication, 

1957). 

Broad terraces near the seacoast about one-half mile 

southwest of the village of Latouche are covered for the 

most part with a sedge meadow plant community 

( Shacklette, 1961). The principal species of sedges are 

Carew Kelloggii Boott, 0. canescens L., 0. macrochaeta 

C. A. Meyer, 0 . sitchensu Prescott and 0. pauciflora 

Light£., with which are also found cotton grass (Eriophorwm gracile Koch) and bur-ned (Sparganium angustifolium Michx.). Few other plant species are present. 

Small pools are conspicuous features of these sedge 

meadows, which are on the gently sloping terraces. 

Many of these pools are highly symmetrical, generally 

rounded to almost circular, as much as 30 feet in diameter, and raised 2 or 3 feet above the general level 

of the ~urrounding meadow (fig. 355.1) . They have 

vertical to slightly overhanging banks or rims, formed 

of the roots and stems of sedges and cotton grass imbedded in reddish-brown peat. Water in the pools is 

open, clear, and 6 to 10 inches deep. The material on 

the bottoms of the pools consists of a·n ooze of unconsolidated dark-brown finely comminuted organic matter 

that extends downward an undetermined depth but 

. grades into rather firm muck or peat at a depth of 

about 2 feet. There is no significant growth of mosses 

in the pools. The rhizomes of the yellow pond lily 

(Nuphar polysepalu·m Engelm.) are loosely imbedded 

FIGURE 355.1.-Sedge meadow pool, Latouche Island, Alaska. 

Leaves of yellow pond lily are floating on the surface. The 

aquatic bur-reed grows in water near the margin (a). 

Sedges ( Oarex and Eriophorwm spp.) form a dense, closed 

sod on the pool rim and island. A break in the rim is beginning to form at the right of the pool (b) ; this will eventually drain the pool. The terrace ridge in the background 

bears a scattered growth of mountain hemlock, Sitka spruce, 

and western hemlock. 

in the ooze of the pool bottoms, and scattered clumps 

of quillwort (I soetes Braunii Durieu) grow completely 

submerged in the shallow water. A few plants of burreed also grow in the pools as emergent aquatics. 

These pools have no apparent surface outlets, and 

the water does not seem to be flowing through them. 

The formation of these pools is believed to begin 

"-ith the damming of a minor surface drainage channel 

by the growth of one or several sedge tussocks, along 

with leafy liverworts, principally Nardia scalaris 

(Schrad.) Gray, and a few mosses, principally 

Drepanocladus species, that grow in and around the 

tussocks. The pool increases in size by an increase 

in height of the dam through growth of the sedges, 

and by the thrusting aside of the banks by ice when 

the water freezes. The outward pressure of the ice 

tends to form a pressure ridge in the peat at the edge 

of the pool, creating an elevated rim (fig. 355.2B) as 

t.he ice of the pool pushes against the still-unfrozen 

sedge margin. The development of an island in the 

pool is a fortuitous occUITence and not a constant feature of sedge meadow pools. These islands appear to 

have originated from the remains of upslope rims that 

had reached sufficient heig_ht to escape flooding and 

disruptive ice action as the pool increased in size (fig. 

355.2B, 0). The disappearance of the sedge tussocks 

from the flooded areas is believed to be due to the substrata becoming excessively wet for these sedge species 

to grow well, and to the mechanical disruption of the 

substrata and the sedge tussocks by ice action. Alter-
D-198 GEOLOGICAL SURVEY RESEARCH 19 61 

B. Enlargement of pool, forming island 

0 2 FEET 

FIGURE 355.2.-Sketches showing evolution of a sedge meadow 

pool. Non-tussock forming sedges have been omitted. The 

tussocks are broken up as the pool rim and island form. 

nate freezing and thawing of the saturated fibrous peat 

substrata is probably the principal factor in the formation of the ooze on the pool bottom. 

The continued development of sedge meadow pools 

leads to their eventual destruction. Field observation 

suggests that when the pools have attained a diameter 

of 20 to 30 feet a break generally occurs in the downslope rim (fig. 355.1). The pool is thus drained, and 

the old pool bottom is then colonized by the more 

hydrophytic species of sedges and cotton grass. The 

ridged, furrowed, and hummocky microrelief of the 

sedge meadow is caused by the persistence of the old 

pool rims, islands, and pool bottoms. Foot travel over 

this terrain is difficult because of the surface irregularities which are often concealed by the dense sedge 

growth; numerous pools and soft bottoms of old pools 

also must be avoided. 

Other bodies of water in this vicinity range in size 

from that of the sedge meadow pools to small lakes 

(for example, Fish Lake and Lake Putnam, shown on 

the map of Latouche Island, the Seward A-3, 1:63,360 

quadrangle). These pools or lakes lie in slight depressions, have flowing outlets, and do not have elevated 

margins or rims. It is believed that their origin and 

history are directly related to the major drainage patterns of the terrain, and that they were not derived 

from the unique sedge meadow pools described in this 

report. 

REFERENCES · 

Shacklette, H. T., 1961, Substrate relationships of some 

bryophyte communities on Latouche Island, Alaska: 

Bryologist, v. 64, p. 1-16. 

Stejer, F. A., 1956, Pyrite deposits at Horseshoe Bay, Latouche 

Island, Alaska: U.S. Geol. Survey Bull. 1024-E, p. 107-122. 

356. REGIONALLY METAMORPHOSED METALLIFEROUS CONTACT-METASOMATIC DEPOSITS NEAR NOME, 

ALASKA 

By C. L. HUMMEL, Bangkok, Thailand 

Anomalously large amounts of bismuth, copper, 

molybdenum; and zinc in sediments from Thompson 

Creek (a western tributary of the Grand Central 

River) in the IGgluaik l\1ountains have been reported 

previously (Hummel and Chapman, 1960), but when 

first reported the source of the metals was unknown. 

These metals are now thought to have been derived 

from erosion of metamorphosed contact-metasomatic 

deposits. Four such deposits have been identified near 

Thompson Creek: two are west of the Thompson Creek 
.... 

SHORT PAPERS IN THE GEOLOG:rC AND HYDROLOG:fC SCIENCES, ARTICLES 293-435 D-199 

drainage and two are on either side of the Grand 

Central River above the mouth of Thompson Creek 

(fig. 356.1). 

In Thompson Creek, stream sediments containing 

henvy metals in the light fraction and scheelite in 

heavy-mineral concentrates are downstream from a 

wide bel~ of sulfide-bearing calc-silicate rock formed 

along the contact of a thick gneissic granite sill (C. L. 

Sainsbury, oral communication, 1960). ~ietamorphosed deposits lie along the contact of this same 

gneissic granite sill at points 4 and 7 miles west o'f 

Thompson Creek. 

The contact-metasomatic deposit west of the. Grand 

Central River lies along the contact between a body of 

qunrtz-plagioclase-biotite gneiss and interbedded marble and biotite schist. The gneiss is believed to be a 

metamorphosed granodiorite sill. The bedrock relations of the deposit on the east side of the river are 

unknown. 

The contact-metasomatic deposits are difficult to recognize, for they have been recrystallized during the 

regional metamorphism of the enclosing sedimentary 

and igneous rocks, which has produced calc-silicates 

very similar to the contact rock developed near the intrusives. The four deposits shown on figure :156.1 contain scheelite-bearing contact silicates, and the westernmost deposit contains galena and sphalerite associated 

with scheelite. 

The contact-metasomatic deposits assoriated with 

regionn.lly metamorphosed intrusive masses represent a 

type of lode deposit hitherto unrecognized in the N orne 

area. Sitnilar deposits may be associated with other 

metn,-igneous rocks in the Kigluaik Mounta.ins, and in 

high-grade metamorphic rocks in the Bendeleben and 

Darby Mountains on the Seward Peninsula. 

REFERENCE 

Hummel, C. L., and Chapman, R. M., 1960, Geologic and economic significance of some geochemical results obtained 

from stream sediment samples near Nome, Alaska, in Short 

papers in the geological sciences: U.S. Geol. Survey Prof. 

Paper 4~B, p. B30-B33. 

EXPLANATION 

META-IGNEOUS ROCKS 

m 

Metagranitic sill 

B 

Metagranodioritic sill 

METASEDIMENTARY ROCKS 

8 Interbedded chlorite schist and marblt! 

El Interbedded quartzite and staurolite- nnd 

sillimanite-bearing biotite schist 

In.terbedded marble and 

~ 

sillimanite-bearing 

~ biotite schist 

Contact-metasomatic deposit containing scheelite or sulfides 

1 

•· Geochemical sediment sample site 

Contact 

Outline of drainage basin of Thompson Creek 

u 

D 

Fault, showing dip 

U, upt~rown side; 0, downthroum Bide 

....,.... 

u~ -0 ON NO 0(1) 

ww 

~~ 

o..a:: 

0 

u 

2 

0 

w 

.J 

c( 

0.. 

Strike and direction of dip of foliation,generally parailel to bedding 

FIGURE 356.1.-Geologic map of part of the Kigluaik Mountains 

near Nome, Alaska, showing metamorphosed deposits and 

~ediment sample sites. 
D-200 GEOLOGI·CAL SURVEY RESEARCH 19 61 

357. MULTIPLE GLACIATION IN THE HEADWATERS AREA OF THE DELTA RIVER, CENTRAL ALASKA 

By TRoY L. P:Ewi, College, Alaska 

At least four Quaternary glaciations, each successively less extensive than the former, are recorded on 

the south side of the central Alaska Range in the headwaters area of the Delta River, an area of broad valleys 

and low mountains. These mountains, nanied the 

Amphitheater Mountains because of small cirque glaciers on the north-facing slopes, have a relief of 2,000 

to 3,000 feet (fig. 357.1). A reconnaissance study was 

made of the entire area,· and detailed investigations 

were made in the vicinity of High Valley. 

In the past, glaciers pushed south from the Alaska 

Range, and some ice was confined to the wide, deep, 

major river valleys, such as the Maclaren. Much of the 

0 

ice, however, filtered through gaps and passes in the 

An1phitheater Mountains and was joined by' local glaciers. A small percentage of the ice from the south 

side of the Alaska Range found egress to the north 

through the Delta River pass (Pewe and others, 1953, 

p. 8). 

The earliest glacial ad vance recognized is thought to 

be early to middle Quaternary age. This ad vance covered the 6,000-foot peaks of the Amphitheater Mountains and pushed south into the Copper River Basin. 

No till of this advance is known, but isolated erratics 

up to 15 feet in diameter occur on top of Paxson Mountain and an unnamed peak in the Amphitheater MounEXPLANATION 

L2£J 

Deposits of very late Quaternary age 

R 

Denali ~ glaciation 

Deposits of late Quaterna711 age 

Q4 , late Deno.li advance 

Q3 , early Denali advance 

B 

Deposits of middle to late Quaternary age 

--;..o1 

Glacial erratics of early to middle Quaternary age 

10 MILES 

D 

Bedrock 

Glacial ov~ow channel 

Contact 

Geology by Troy L. Pewe' 

LOCATION MAP 

I CONTOUR INTERVAL 1000 FEET DATUM IS MEAN SEA LEVEL 

FIGURE 357.1.-Glacial deposits in the headwaters area of the Delta River, Alaska. 
SHORT. PAPERS IN THE GEOLOGFC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-201 

tains (fig. 357.1). A north-trending overflow gorge 

across the crest of Paxson Mountain was possibly cut 

during this glaciation. This advance is tentatively correlated with the Darling Creek advance recorded in the 

lower Delta River area ( Pewe, 1952). 

The second glacial ad vance pushed south to the Copper River Basin but did not cover the peaks of the 

Amphitheater Mountains. Many overflow channels 

were cut where drainage escaped over low places in 

ridges which protruded ~nly slightly above the ice surface. These ridges now display high and dry water-cut 

gushes which are best exhibited just outside the southern border of the mapped area. This advance, thought 

to be middle to late Quaternary age, left an olivecolored silty till covering the lowlands and flanking the 

lower slopes of the Amphitheater Mountains. This till 

is now covered by later Quaternary drift or· rubble 

sheets except above an elevation of 4,000 feet and on 

the floor of I-Iigh Valley. No morainal forms of this 

glaciation are preserved in the area, probably because 

the drift has been covered by younger drift or rubble 

sheets. This glacial advance is tentatively correlated 

with the Delta glaciation of the lower Delta River 

(Pewe and others, 1953). 

The next two glacial advances took place in late 

Quaternary time and are closely related in extent and 

age. They are here grouped together and named the 

Denali glaciation, after the Denali Highway, which 

traverses the deposits of these advances in the Amphitheater Mountains. The Denali glaciation is correlated 

with the complex Donnelly glaciation of the lower 

Delta River (Pewe, 1952). 

These two advances did not cover the Amphitheater 

Mountains, but moved through gaps and were joined 

by local cirque ice. Ice waS, thick in major valleys 

such as the Maclaren River valley· on the south side 

of the range, but was thinner over interfluves. Upon 

retreat, much of the ice in the headwaters area of the 

Delta River thinned and stagnated. 

Well-preserved moraines, characterized by fresh 

knob-and-kettle topography, are typical of drift of late 

Denali age; moraines of early Denali age are more 

604493 0--6t--14 

subdued, less effective in deflecting surface drainage, 

and slightly more extensive (fig. 357.1). 

As the ice from the late Denali advance in the area 

stagnated many ice-contact features formed : eskers, 

kan1es and kettles, crevasse fillings, and pitted surfaces. 

The Tangle Lakes at the headwaters of the Delta River 

comprise a classic area for such features. They are 

strikingly fresh and cover an area of several hundred 

square miles. 

Glacier-free lower slopes, especially north-facing 

slopes, in the Amphitheater Mountains are blanketed 

by a 3- to 7-foot thick sheet of no\~' inactive rubble 

that was derived from higher slopes by fJrost riving during the rigorous climate of the time of the Denali glaciation. Some of the rubble sheets cover older till in 

Jiigh Valley. 

During a read vance of the ice in very late QuaterIlary time (the fourth glaciation) ice streams on the 

south side of the central Alaska Range did not extend 

far enough to go through the gaps in the Amphitheater 

Mountains. Small glaciers in the Amphitheater Mountains deposited arcuate moraines at the mouths of short 

valleys at altitudes lower than the prominent lateral 

moraines deposited during the late Denali glaciation. 

Cirque glaciers of the Amphitheater Mountains 

have advanced twice in historic tim.e, each advance 

leaving two small sharp morainal ridges of angular 

rubble within a few hundred yards of the present ice 

fronts. These deposits are about 5,000 feet above sea 

level and are perhaps correlative with moraines deposited within the last two centuries by glaciers in the 

Delta River pass (Pewe, 1951, 1957). 

REFERENCES 

Pewe, T. L., 1951, Recent history of Black Rapids glacier, Alaska 

[abs.]: Geol. Soc. America Bull., v. 62, p. 1558. 

--1952, Preliminary report of multiple glaciation in the 

Big Delta area, Alaska [abs.]: Geol. Soc. America Bull., 

v. 63, p. 1289. 

--1957, Recent history of Canwell and Castner glaciers, 

Alaska [abs.]: Geol. Soc. America Bull., v. 68, p. 1779. 

Pewe, T. L., and others, 1953; Multiple glaciation in Alaska-a 

progress report: U.S. Geol. Survey Circ. 289, 13 p. 
D-202 GEOLOGICAL SURVEY RESEARCH 19 61 

358. RECESSION OF PORTAGE GLACIER, ALASKA 

By RUTH A.M. ScHMIDT, Anchorage, Alaska 

Portage Glacier occupies a pass in the Kenai-Chugach 

Mountains between Cook Inlet and Prince William 

Sound at the southeastern end of Turnagain Arm, 

Alaska, in the Chugach National Forest. Because it 

is close to Anchorage and to the Seward Highway, 

the U.S. Forest Service has built a road to the area 

and provided picnic grounds and campsites. Examination of maps and photographs show that the glacier 

has receded 1.9 miles in 45 years; during this time a 

proglacial lake called Portage Lake formed behind a 

terminal moraine. 

In 1898 Mendenhall twice .crossed the glacier, and 

stated (Mendenhall, 1900, p. 301) ~ · 

• • • the isthmus connecting Kenai Peninsula and the mainland is crossed in a portage of about 12 miles to the head of 

Turnagain Arm. A glacier covers 4 or 5 miles of this isthmus, 

and its highest point is 1,000 or 1,100 feet above the sea, with 

a steep approach from the east. • • • This portage over the 

glacier is one of the oldest routes in Alaska, since more than 

a hundred years ago Captain George Vancouver reported that 

it had been long used by Russian and Indian tr:;tders as. a 

means ot communication between Cook Inlet and Chugatch 

Gulf [now Prince William Sound]. 

The route was used at that time only during the 

winter and spring months because of crevasses in the 

glacier during the summer. In 1914 it could still be 

crossed on a trail, but by 1939 a lake had formed in 

front of the glacier, and the surface had become too 

badly crevassed for passage. 

Botanical evidence (Viereck, 1960, and oral communications, 1960) indicates that the last major advance of Portage Glacier culminated about 1893. As 

far as can be determined, the glacier reached about 

the same position then that it occupied in 1913-1914 

when maps of the glacier were made in connection with 

studies for the Alaskan Engineering Commission. A 

terminal.moraine that is present at this point dams the 

proglacial Portage Lake. No other terminal moraines 

have been seen in Portage Valley beyond this one. 

Maps based on surveys by the Alaskan Engineering 

Commission in 1914 and the Alaska Railroad in 1939 

(Barnes, 1943, pl. 16), and aerial photographs tak~n 

in 1950, 1951, and 1959 provide the following data on 

the recession of the glacier: 

Period: 

1914 to 1939 (25 years) _______________________ _ 

1939 to 1950 (11 years) ________ . _______________ _ 

1950 to 1959 (9 years) ________________________ _ 

1914 to 1959 (45 years)---------------~-,..--

Approximate 

recession of ice front, ln 

feet (fig. 958.1) 

3,000 

5,500 

1,500 

10,000 

In 1913 elevations above sea level were measured at 

points A and B (fig: 358.1) on the nor.theast side of the 

surface of the glacier (Giffen and Bagley, 1914). 

Elevations at these points in 1913 and in two later years 

are given below: 

Elevation (feet) 

Date Remarks 

A B 

1913 _____ 492 934 

1939 _____ -------------- 734 Surface reported as "at least 

200 feet lower" (Barnes, 

1943, p. 231). 

1950 _____ Lake surface 550 Estimated from topographic 

c< 15o) map, Seward D-5. 

Barnes ( 1943, p. 232) reports that in 1939-

Soundings in ••• [Portage Lake] ••• revealed •a maximum depth 

of 400 feet a•t the glacier front 2,000 feet southeast of the tip 

of Turnagain Shoulder, and depths of more than 200 feet at 

. several places within 400 to 600 feet of the south and west shores. 

In July 1960 soundings taken by the ·writer in approximately the same area as the 1939 glacier front gave 

depths of 250 feet to 260 feet, indicating that sediment 

about 150 feet thick had been deposited. The depth of 

the lake increased sharply from the terminal moraine 

to depths of more than 125 feet within 100 feet of the 

shore. A maximum depth of 595 feet was measured. 

about 1,000 feet from the glacier front. Because of 

continual calving, no closer soundings w~re taken. 

Measurements will continue to ·be made and photographs ta.ken to provide a. continuing record. Undoubtedly the recordbrea.king high temperatures and low 

precipitation of the 19·60-1961 winter will have a 

marked effect on the regimen of all the glaciers in 

Alaska. 
SHORT PAPERS IN TH~. GEOLOGI·C AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-203 

0 1 MILE 

CONTOUR INTERVAL 500 FEET 

FIGURE 358.1.-Portage Glacier area, Alaska, showing glacier fronts from 1914 to 1959. 

(Points .4. and B are described in text.) 

REFERENCES 

Barnes, F. F., 1943, Geology of tlie Portage Pass area, Alaska : 

U.S. Geol. Survey Bull. 926-D, p. 211-235. 

Giffin, C. K, nnd Bngley, .J. ,V,, 1014, Reconnaissance map, Passnge Canal to 'l'urnagain Arm, in Brooks, A. H., and others, 

Mineral resources of Alaska, 1913 : U.S. Geol. Survey Bull. 

592, p. 50. 

Mendenhall, W. C., 1900, A reconnaissancEl from Resurrection 

Bay to the Tanana River, Alaska, in 1898: U.S. Geol. Survey 20th Ann. Rept., pt. 7, p. 265-340. 

Viereck, L. A., 1960, Botanical dating of rc~ent glacial activity 

in Alaska: Program, 11th Alaskan Science Conference, 

Anchorage, Aug. 31, 1960. 
D-204 GEOLOGICAL SURVEY RESEARCH 19 61 

359. RELATION OF DISCHARGE RATE TO DRAWDOWN IN WELLS IN OAHU, HAWAII 

By E. R. LUBKE, Honolulu, Hawaii 

Worlc done in cooperation with the State ot Hawaii 

The relation of discharge rate to dra wdown in pumping wells has been determined for wells that tap 

artesian and unconfined basal ground water in the 

basaltic lava flows in the Koolau Range of Oahu, 

Hawaii. This aquifer, which is generally highly permeable, supplies large quantities of water to municipal, 

irrigation, and industrial systems on the island. The 

study was made to determine whether predictions of 

dra wdown and yield could be made from a few observations in a pumping well. Data from step-dra wdown 

tests in 22 wells were examined in the study. 

3000 

2000 

1000 

.. 

:; 

c: 

·e 

; 500 

0.. 

"' c: 

~ 0 

00 3oo c 

. 

• 

~ 200 .. 

0 

~ ~ 

t~;,'O''l.~ u 

... 

0 ,, 'l. --'e 100 

so 7 -1 // 

fJ"'I,/ 

\ 'l. ,~ 

30 _.~~.' '!!''' ,, 

~· 

20 0.03 0.05 0.1 0.2 0.3 0.5 

Most of the wells studied are uncased in the saturated 

part of the rock; a few have perforated casing. 

Diameters of the holes in saturated rock range from 

6 to 16 inches. The area of the intake parts of the wells 

range from ·60 square feet to about 690 square feet. 

The ratio of discharge rate to drawdown (specific 

capacity) at variable rates of discharge in a given well 

generally is nonlinear, but decreases with increasing 

discharge. This decrease results partly from head 

losses ·due to turbulent flow in (a) that part of the 

aquifer adjacent to the well, (b) through the perforated 

1.0 2.0 3.0 

DRAWOOWN, IN FEET 

FIGURE 359.1.-Relation between discharge rate and drawdown in five wells tapping water in basaltic lava flows in Oahu, 

Hawaii. 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 !D-205 

casing, and (c) inside the well casing. A nonlinear 

relation between discharge and drawdown could arise 

also in part from nonlinear boundary conditions at the 

water table in the vicinity of the pumping well. 

For nearly all wells in which three or more drawdown 

measurements at different discharge rates were taken 

during a pumping test, the discharge and drawdown 

show a nonlinear relation. Examples of the relation 

are given on figure 359.1, which show's the results of 

pumping tests on 5 wells. The relation can be 

expressed mathematically in the equation 

Q=a8b (1) 

'in which Q is the discharge rate, a and b are constants 

relnted to head losses, and 8 is the drawdown within 

the well. The logarithmic expression for this equation 

lS 

log Q=b log 8+ log a (2) 

in which log Q is expressed as a linear function of log 8. 

The constants .a and b are determined by the method of 

least squares. 

The observed dra wdown at different discharge rates 

and the resulting specific capacity in well :256-2A 

(fig. 359.1) are as follows : 

Discharge rate (Q) (gallons per minute) 

520 _______________________ _ 

540 _______________________ _ 

700 _______________________ _ 

8oo _______________________ _ 950 _______________________ _ 

1,130 ______________________ _ 

Drawdown (s) 

(feet) 

0. 8 

.8 

1.4 

1.7 

2. 5 

3. 6 

Specific capacity (Q/s) 

(gallons per minute 

per foot) 

650 

675 

500 

471 

380 

314 

From these data the computed value of log a is 2.77 

and the value of b is 0.51. The curve for. this equation 

for well 256-2A is shown on figure 359.1. 

From the given relation, drawdown can be estimated 

gra.phically or mathematically for a discharge rate that 

is greater or less than, or that falls within the range of 

measurements taken during a step-drawdown test. 

The specific capacity also is seen to decrease with increase in discharge rate. 'l'he method described may 

apply to wells drilled in other types of aquifers. 

360. PRELIMINARY GRAVITY SURVEY OF KILAUEA VOLCANO, HAWAII 

By H.·L. l{ruvoY and J.P. EATON, Hawaiian Volcano Observatory, Hawaii 

Kilauea is the smaller of two active shield volcanoes· 

that form the southern half of the Island of Hawaii. 

The swnmit of IGlauea is a slight protuberance on 

Mauna Loa's easterly flank, and the region bebYeen the 

two summits contains the intercalated products of each 

volcano. 

Eruptions of J(ilauea have taken place either in the 

region of the sumn1it or else along one of l{ilauea's 

two conspicuous flank rifts. The southwest rift was 

last active in 1920 and is 1narked by an extensive pattern of linear cracks. The eruption of 1959-1960 

(Eaton and J\{urata, 1960; Richter and Eaton, 1960) 

began as a summit eruption in the pit crater Kilauea 

Ild and continued as a flank eruption at the Kapoho 

graben in Puna, some 30 miles from the summit. This 

active region is the coastal tenninus of the east rift 

zone, which extends from J(ilauea summit as a low 

topographic ridge. · 

In 1957 and 1958, elevation loops were run in the 

summit and east-rift sectors of Kilauea. Bench marks 

were spaced along these loops at intervals of one half 

and three tenths of a mile near the rifts, and at inter- · 

vals of one 1nile in more stable regions. The elevations 

determined during these surveys and during re-leveling 

of the summit in 1960 served as the basis of the 1959-

60 gravity survey here described. 

Tilt studies and elevation surveys before and after 

the 1959-1960 eruption show that IGlauea summit was 

progressively inflated before the l{apoho flank eruption 

and then suddenly deflated contemporaneously with 

the eruption. Summit deformation decreased symntetrically fron1 a maximum collapse of about 5 feet 

on the floor of the caldera to an undetectable amount 

about 5 1niles from the smnmit. Vvilson (1935) reports 

similar smnmit pulsations for other volc.:"tnic epochs. 

A gravity survey was made in the summit region of 

IGlauea in December 1959 and Jmnutry 1960. The 

survey WftS repeated in March and April1960, after the 

major subsidence described above. Bouguer anomalies 

shown on figure 360.1 have been computed ·using the 
D-206 GEOLOGICAL SURVEY RESEARCH 19 61 

61.1 

{ ol :1. 

:zo.o 

Gravity station and value 

Bouguer contour interval 10 milligals 

1-------..,....-=---..Y.'---+---+----.~-------r--+-- Topographic contour interval 500 feet 

0 4 MILES 

155"25' 155"20' 155"15' 155"10' 

FIGURE 360.1.-Positive Bouguer gravity anomalies (heavy broken lines) for the summit region of Kilauea 

volcano. Some gravity values have been omitted for sake of clarity. 

March-April gravity data together with elevations determined in May and June 1960 for summit bench 

marks. 

Gravity work in the Puna area (fig. 360.2) 'vas completed in February 1960, during the east-rift eruption. 

Eleva,tions used in the reduction of these data are based 

on the survey of 1958. Eight hours before the Kapoho 

eruption vertical displacements on the order of several 

feet were observed along the two border faults at the 

Kapoho graben. About a dozen bench marks in this 

vicinity were buried by 1960 lava. It is possible that 

data computed for these points, based .on uncertain 
SHORT PAPERS IN THE GEOLOGIC AND. HYDROLOGIC SCIENCES, ARTICLES· 293-435 D-207 

-...... 

' 

EXPLANATION 

Gravity station and value 

Bouguer contour interval 10 milligals 

--.~-+-'1~-------J....QPographic contour interval 500 feet 19'20' 

o.__..._ _ _.__ _ __._ _ __,4 MILES 

155'00' 154'55' 154'50' 

FIGURE 360.2.-Positive Bouguer gravity anomalies (heavy broken lines) for the east flank (Puna area) 

of Kilauea volcano. Some gravity values have been omitted for sake of clarity. 

elevation, might be in error by three or four tenths of a 

milligal. 

A vn1ue of 2.3 g per cm3 obtained by "Toollard (1951) 

for Oahu was adopted for the average density of the 

island mttss in computing Bouguer ttnoma.lies. Bouguer 

anomalies so computed for the 1\:ilauea summit and 

Puna regions reflect the topography 9f the volcano as 

does vV oollard's Bouguer a.non1aly for Waianae volcano 

on Oahu. Thus, the anomaly contours are para.llel to 

the topographic contours· along IGlauea's southeastern 

coast, where both are also parallel to the east rift zone. 

North of the rift zone, however, Bouguer anomaly contours cut sharply across the topography and follow the 

rift zone. To reduce the apparent correlation between 
D-208 GEOLOGICAL SURVEY RE-SEARCH 19 61 

Bouguer anomaly and topography, where it exists, it 

might seem. reasonable to adopt a bulk density closer 

to the conventional value of 2.9 g per cm3 for dense 

basalt. · This might be justified for lavas erupted beneath the sea under pressures that restrict the formation 

of vesicles. However, there is little reason to believe 

that the parts of the volcanoes above sea level, which 

alone are involved in the Bouguer reduction, have been 

so constrained. Indeed, estimates of the bulk density 

of basalt once covered by several thousand feet of 

younger lavas and la.ter exposed by erosion are close 

to the value of 2.3 g cm3 found by "'Voollard. for the 

. entire ridge when he applied gravity-profiling theory 

to Vening Meinesz' submarine profile. 

The Bouguer anomaly rises from about +250 milligals along J{ilauea's southeastern coast to + 320 milligals at the center of J{ilauea caldera at an elevation of 

about 3,600 feet. It then drops off steadily northwestward over the southeastern flank of Mauna Loa to + 290 

milligals at an elevation of about 4,800 feet. Beyond 

this point the anomaly remains virtually constant to an 

elevation of 6,700 feet, where the presei1t survey ends. 

In accordance with Wollard's interpretation of the 

large positive Bouguer anomalies around the two main 

eruptive centers on Oahu, it is likely that the strong 

positive anomaly that is centered at Kilauea caldera and 

extends out along the east rift zone is largely caused by 

a complex of dense dikes at the core of Kilauea. It is 

also possible that the sha.Ilow reservoir beneath the caldera, which is revealed by the pattern of elevation 

changes and tilt accompanying eruptive activity, is responsible for part of the anomaly. Additional gravity 

measurements on Kilauea volcano may help define the 

physical boundaries of this dike system . 

REFERENCES 

Eaton, J. P., and MuraltJa, K. J., 1960, How volcanoes grow: 

Science, v. 132, n. 3432, p. 925-938. 

Richter, D. H., and Eaton, J. P., 1960, The 1959-60 eruption of 

Kilauea Volcano: .New Scientist, v. 7, p. 994-997. 

Wilson, R. M., 1935, Ground surface movements at Kilauea 

Volcano, Hawaii: Univ. of Hawaii Research Pub., no. 10. 

Woollard, G. P., 1951, A gravity reconnaissance of the island of 

Oahu: Am. Geophys. Union Trans., v. 32, p. 358-368. 

EXTRATERRESTRIAL STUDIES 

361. THICKNESS OF THE PROCELLARIAN SYSTEM, LETRONNE REGION OF THE MOON 

By C. H. MARSHALL, Menlo Park, Calif. 

Work done on behalf of the National Aeronautics and Space Administration 

The stratigraphy of the Letronne region of the Moon 

is being investigated as part of a study of the lunar 

surface. The region lies in the general target area for 

a number of hard-landing lunar capsules to be launched 

as part of the National Aeronautics and Space Admin-

. istration Ranger Program. The Procellarian system is 

the most extensively expo.sed stratigraphic unit in part 

of the target area. 

Stratigraphic units exposed in the Letronne region 

include the major units thus far recognized on the Moon 

(Shoemaker and Hackman, 1960); these are pre-1mbrian material and the Imbrian, Procellarian, Era.tosthenia.n and Copernican systems ( Shoema.ker, in press) . 

The Imbrian system and pre-Imbria.n material, the lowest stratigraphic units, cover much of the southern quarter of the Letronne region a.nd are exposed in numerous 

widely scattered smaller areas (fig. 361.1A.· These units 

have a medium albedo and underlie a generally irregular surface upon which are craters ranging from less 

than 1 km to 130 km across. Most of the isolated ex-· 

posures of the Imbrian and pre-Imbria.n are the rims of 

large craters that have been partly buried beneath 

higher stratigraphic units, belonging chiefly to the Procellaria.n system. 

The Procellarian system is characterized by low albedo and underlies extensive areas of generally low relief that occupy 82 percent of the Letronne region. 

Ridges of low amplitude, which have been interpreted as 

· anticlines, and a few low domes and shallow valleys 

termed rilles are present on the surface of the Procellarian. The estimated thickness of the Procellarian 

varies from a featheredge to several thousand meters; 
50•E 46•E 42•E 38•E 34•E JO•E 

o·s 1 •• •• ..Qoo=--'l:'+ __ .. , • 8 _, c , , 7 1 o·s 

4•s 

s·s 

12·s 

16•$ i ON' 

5o·E 46·E 

Base map by U.S. Air Force 

Aeronautical Chart and 

Information Center, 1960 

42°E- 38°E 

0 25 50 75 100 125 150 KILOMETERS I I I I II I I I I" I I I 

0 25 50 75 100 MILES I I I I I I I I I L.J I I I I I I I I I I 

4•s 

s·s 

12•s 

0 C ,,-"V \ .)-/ #j?f M".i!"e I 1605 

34•E Jo•E 

Geology by C. H. Marshall, 196.1 

EXPLANATION 

STRATIGRAPHIC UNITS 

E3I] 

Ejecta, breccia, and talus of the Copernican 

and Eratosthenian systems, undifferentiated 

D Mare material and dome material of 

the Procellarian system 

Ejecta, breccia, and possibly volcanic or other 

kinds of rocks. Includes rocks of the 

lmbrian system and pre-Imbrian material, 

undifferentiated 

Contact 

t 

• 

Anticline 

Slwwinq crest line and direction qf plunge 

Isopach line, showing thickness of 

Procellarian system 

Long dash where based on ideal interior profile of 

buried crater; isopach interval 600 meters. Short 

dash where based on ideal exterior profile of buried 

crater or contact of Procellarian system; isopach 

interval 800 meters. 800 meter contour is not shown 

on interior wall qf buried craters 

INDEX MAP OF THE MOON SHOWING LETRONNE REGION 

FIGURE 361.1.-Preliminary isopach map of the Procellarian system, Uetronne region of the Moon. 

~ 0 

~ 

"' > "' t:r.l 

::tl 

Ul 

~ 

z 

~ 0 

t:r.l 

0 

t'4 

0 

0 

a 

~ t::;1 

~ ~ 

::tl 

0 

t'4 

0 

0 

~ 

(") 

~ ~ 

t:r.l 

~ () 

t:r.l 

~Ul 

> ::tl 

~ 

~ Ul 

~ 

<0 

~ 

I 

~ 

~ 

~ 

~ 8 
D-210 GEOLOGICAL SURVEY RESEARCH 19 61 

variations are due mainly to relief on the contact at its 

base. 

The Eratosthenian system, characterized by low to 

medium albedo, and the Copernican system, characteri:l;ed by relatively high albedo, are distributed in numerous isolated patches that overlie the Procellarian and 

lower stratigraphic units. These patches are chiefly 

ejecta associated with craters ranging from 1 km to 

about 20 km in diameter. 

The thickness of the Procellarian system, the most 

extensively exposed unit in the Letronne region, can be 

estimated by reconstruction of the buried pre-Procellarian topography. Twenty partly filled or buried craters of pre-Procellarian age that are widely distributed 

over the Procellarian area of exposure have been identified. Examples of such craters are Letronne, Billy, 

and the large partly circular features near Flamstead 

and Wichmann (fig. 361.1). The exposed parts of the 

rims of these craters provide the control for this reconstruction. 

Baldwin (1949, p. 128-138) has found that the depths 

of lunar craters and the heights of their rims above the 

surrounding terrain are roughly related to the crater 

diameters (fig. 361.2). He has expressed the depths of 

the craters and the heights of the crater rims as functions of the crater diameters. The scatter of observed 

dimensions from the fitted curves (fig. 361.2) is large, 

but the curves may be used to calculate average expected 

depths and rim heights for craters of known diameters. 

No clear-cut bias or systematic departure from the 

curves has been found for craters whose stratigraphic 

position has been determined. In particular, depths 

and rim heights of unfilled pre-Procellarian craters appear to be as great in proportion to diameter as the 

depths and rim heights of Eratosthenian and Copernican craters. 

The diameters of the buried craters and elevation of 

the crests of the crater rims above the Procellarian surface were determined from the U.S. Air Force Aeronautical Chart and Information Center Lunar Chart, 

Letronne sheet. Points-on buried parts of the exterior 

slopes of pre-Procellarian craters were obtained on the 

assumption that rims merge 'Yith the surrounding terrain at a distance of half a crater radius. The depth 

of each crater center was calculated by subtracting the 

figure obtained from Baldwin's curve from the highest point on the rim. The possible presence of central 

peaks within the craters was ignored except where part 

of the peaks appeared to be exposed. Letronne is the 

only crater in which a central peak is accounted for. 

Thickness of the Procellarian was determined by subtracting elevations at the calculated points on the preProcellarian surface from the elevation of the Procellarian surface. The difference between total crater 

12 

10 

:it5~ c..LI.. 8 

wLI.. 

>0 

OUl 

ceo 

<z 6 

1-< :rUl (.!l::::l 

-o W:r 4 :rl-

:::!!z 

o:-

2 

0 

25 

Zt-

-w 20 -w 0::1.1.. 

w I-Ll.. <O 

0:: 15 (.)Ul 

0 Ll..z 

Oct 

:rUl 10 !:; 1-::::l c..O 

w:r 

ot- 0 

5 

0 

0 

0 20 

DIAMETER OF CRATER, IN MILES 

40 60 80 100 120 

DIAMETER OF CRATER, IN MILES 

EXPLANATION 

Craters plotted by Baldwin 

0 

Craters of Copernican age 

0 

Craters of Eratosthenian age 

!:; 

Craters of pre-Procellarian age 

(unfilled) 

140 160 

FIGURE 361.2-Curves by Baldwin (1949) showing relation between height of rim, depth of crater, and crater diameter. 

depth and height of rim above the Procellarian surface 

yields a figure for Procellarian thickness at the buried 

crater centers. A total of 58 points outside and inside 

the craters \Yere calculated. The contact of the Procellarian system with the pre-Procellarian, which is the 

line of vanishing or zero thickness, provides additional 

control. 

"'\Vithin the buried parts of the craters, isopach lines 

(isopleths of equal thickness) were drawn to conform 

with an ideal crater shape, which is steep walled from 

the rim inward for a distance of one-third the radius 

and like a nearly flat saucer in the central part. Outside 

the craters, the isopach lines were drawn by mechanically interpolating between the calculated points and the 

zero contour. 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-211 

" 7here Eratostheninn and Copernican craters are snperirnposed on the Procellnrian, the depth of these 

younger craters was taken into account in determining 

the loca 1 thickness of the Procellarian. It is ·possible, 

however, and perhaps likely that n lens of breccia that 

intersects the entire thickness of the Procellnrian underlies most of the Eratosthenia.n and Copernican craters 

shown. 

~'[ost: of the partly buried craters identified in the 

Letronne region are easily recognized on good photographs, but the identi ficntion of a fe''" nearly completely 

buried crnters is nncertnin. The test used for presence 

of a buried crater was to s'ving a compass centered at 

t.he supposed crater center to see if a circle would touch a 

sufficient number of pre-Procellarian expos-ln·es to establish an approximately . circular configuration of the 

crnter rim \Yithout enclosing isolated pre-Procellarian 

exposures. The only exception made to this test was 

for the central peak of Letronne. :Many completely 

buried small-scale features are undoubtedly present, and 

a correct isopach map of the Procellarian would be 

more complex than the one drawn. 

The scatter of observational points around Baldwin's 

curves (fig. 361.2) indicates the rim heights and crater 

depths may differ from the calculated dimensions by 

more than a factor of 2 in a few percent of the cases. 

More data are needed on the dimensions of pre-Procelln.rian craters before a meaningful assessment can be 

made of the precision of the calculated thicknesses. 

Partial fi]]ing of pre-Imbrian craters by the Imbrian 

system could introduce systematiG errors in the preProcellar:ian crater depths calculated for the Letronne 

region. Areas of sparse control lie in the northwest and 

northeast corners and in a small east-central part of the 

region. These areas are the weakest parts of the map. 

The isopach map represents a first attempt to estimate. the thickness of the Procellarian system by a 

realistic method which will give reproducible results. 

Results obtained are a target for ultimate modification 

by seismic or other methods of subsurfaee exploration. 

The method employed is applicable to many other 

regions of Procellaria;n exposure on the M:oon. 

The Procellarian system underlies 240,000 sq km in 

the Letronne region and has a calculated average. thickness of 1.1 kilometers and a volume of 265,000 cu km. 

It is of interest to compare this with the dimensions of 

terrestrial fields of basalt. (See, for example, Hackman, 1960.) The Miocene to lower Pliocene tholeiitic 

basalts of the Columbia River Plateau eover an area of 

about 260,000 sq km and have a volume of about 150,000 

cu km (Waters, 1955, p. 707-708). The. Cretaceous and 

Eocene Deccan basalts of India cover fm area of about 

500,000 sq km and have an average thickness of about 

0.6 km (Emmons and others, 1960, p. 97). 

REFERENCES 

Baldwin, R. B., 1949, The face of the moon : Chicago, Ill., 

Chicago Univ. Press, 239 p. 

11Jmmons, W. H., Allison., J. S., Stauffer, C. It., and Thiel, G. A., 

1960, Geology-Principles and Process,es: New York, McGraw-Hill Book Company, Inc., 491 p. 

Hackman, R. J., 1960, Generalized photogeologic map of the 

Moon, in Engineer special study of the !mrface of the moon : 

Washington, D.C., U.S. Army Map Service. 

Shoemaker, E. M., in press, Geological interpretation of lunar 

craters, in Kopal, Zdenek, ed., The :Moon, its astronomy 

and physics: New Yorl.:, Academic Press. 

Shoemaker, E. M., and Hackman, R. J., 1960, Stratigraphic 

basis for a lunar time scale labs.] : Geol. Soc. America 

Bull., v. 71, p. 2112. 

Waters, A. C., 1955, Volcanic rocks and the tectonic cycle: 

Geol. Soc. America Spec. Paper 62, p. 703-722. 

GEOLOGY AND HYDROLOGY OF OTHER COUNTRIES 

362. REVISION OF THE GEOLOGY OF DIAMOND DISTRICTS IN BAHIA, BRAZIL 

By MAx G. WHITE and CHARLES T; PIERSoN, Washington, D.C. 

The Chapa,da (tableland) Dia.ma.ntina (fig 362.1) is 

a high (900 to 1,200 m) tableland region of flat-lying 

rocks in the central part of the State of Bahia, Brazil. 

Morro do Clut.peu, the principal town and commercial 

center of the Chapada diamond workings, is 290 km 

west of the port. of Salvador. The Serra do Tombador 

is a northerly extension of the Chapada Diamantina. 

South of the Chapada Diamantina is a region of rolling hills that includes the diamond-bearing district of 

Lavras Diamantinas ( diamantiferous workings) and 

the towns of LenQ6is and AndaraL 

Since about 1850 the dia.mond districts of Bahia have 
D-212 GEOT.jOGICAL SURVEY· RESEARCH 19 61 

I 

N 

0 

LAVRAS 

DIAMANT NAS 

Andaraf 

25 50 KM 

); ;odaJane;ro 

FIGURE 362.1.-Sketch map of" the d,iamond districts in Bahia, 

Brazil. 

been a source of industrial and gem-quality diamonds 

and of carbonados. Production .declined in the years 

after World War I, but during the 1920's the region 

was the world's source of carbonados. Diamond production from the region is small and restricted to a few 

scattered primitive operations of individual prospector& / 

The earliest geological work in the region was done 

in the La vras Diamantinas by Derby ( 1906) and in the 

Serra do Tombador region by Branner (1910). Little 

work has been done in the Chapada Diamantina.. Our 

field work shows that physiographically and geologically the Lavras Diamantinas region is a separate province from: the Cha pada Diamantina. 

The sequence of rocks in the Chapada DiamantinaSerro do Tombador-Lavras Diamantinas region is 

shown mi t:ible 362.1. 

Kegel ( 1959) suggested that the geologic sequence of 

this large region is : 

Tombador series ______________ ..:.__________ sapdstone 

Bambui series------------------ limestone and shale 

Lavras series _____ sandstone, conglomerate and shale 

He dropped the name Caboclo shale or series, although 

apparently he included this unit in the Bambui series. 

He did not mention the Jacobina series. 

A proposed revision of the nmnenclature (table 362.1) 

is based on 6 detailed road traverses made with odometer 

and altimeter, and 8 detailed geologic sections measured 

in .the region between Mirangaba and Cafarnaum. 

The outline of the Chapada Diamantina tableland as 

shown. on figure 362.1 is drawn along the 900-m contour 

line. The contour represents theapproximate position 

of the rim of the tableland escarpment, and for the most 

part the enclosed area is occupied by rocks of the Tombador series. The line is dashed on the southern boundary of the region where the limit of the Tombador rocks 

is uncertain. . 

South of the tableland lies rolling country containing 

·folded arenaceous rocks that constitute the Lavras 

series (Kegel, 1959). 

We conclude that the Tombador series occurs in both 

the Serrado Tombador and the Chapada Diamantina. 

In the region west of Jacobina this series is about 100 

m thick and consists· of thin-bedded medium-grained 

sandstone and some siltstone and mudstone. The series 

thickens to the south and in the vicinity of Morro do 

Chapen it is at least 460 m thick, and is composed of 

sandstone, conglomerate, siltstone, and mudstone. The 

Tombador series is generally nearly flat-lying; dips 

greater than 8° to 10° were not observed.· Near Jacobina the Tombador lies on the Precambrian crystalline 

rocks; west of Morro do Chapen, however, it overlies the 

Bambui series. . 

Diamonds are found in the Chapada · Diamantina 

mostly in the vicinity of Morro do Chapen and Ventura in the alluvium of creeks and small streams and in 

eluvial gravels on hill slopes. The sources of the diamonds are conglomerate beds and lenses in sandstone 

found mostly between 900 m and 1,100 m of elevation 

and thus are from the Tombador series. The pebbles 

are mostly well-rqunded and well-sorted quartz and 

average about 1 em in width. Diamonds in the Lavras 

Diamantinas region are largely in alluvial gravels in the 

vicinity of Lell(;6is and Anda.ra.i at an eleva.tion of about 

400 m. The source of the diamonds is reported to be 

the conglomeratic sa.ndstones of . the area and presumably are from the Lavras series. 

If the diamond-bearing horizons have been identified 

correctly, the dia.mond.deposits of central Ba.hia are not 

concentrated exclusively in conglomeratic sandstone of 

the Lavras series as has been assumed by some previous writers. Rather it would seem that diamonds 

were brought in from some outside source during both 

La vras and la.te Tombador times, or that diamonds were 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 2 9 3--4 3 5 D-213 

TABLE 362.1.-Nomenclature of rocks in the diamond districts, Bahia, Brazil 

Oliveira and Leonardos (1943) Proposed r<>vision ~ , this report (based partlv on Kegt>l 1959) -· 

Age Nomenclature 1md reference Age Nomenclature Lithology 

Sandstone conglomerate, 

Silurinn or Ordovi- Bambui series t Tombador series quartzite, siltstone, mudcia.n Early stone. 

Paleozoic 

Bambui series Varicolored limestone 

Eocambrian Lavras series (Derby, 1906) Lavras series Conglomeratic sandstone 

l=l 

4'!1 Upper Paraguassu series (Derby, 1906) _ :.;;l 

.:l (Caboclo series; Branner, 1911) t:: Jacobina series Quartzite, sandstone; basal 0 0:: bO 'i: quartzite conglomerate. < ..0 

Lower Tombador series (Branner, 1910b) s 

0:: 

0 

Cll 

~ "'"' Granitic rocks, orthogneiss, 

Archean Crystalline rocks Early Crystalline rocks paragneiss. 

1 Also cnlllld Sno Francisco series, VC\Sn Bnrrls series, Salitre limestone, IUld Una formation. 

first _concentrated in the Lavras series and some were 

later reworked during erosion of ·the Lavras and r~­

deposited in the Tombador. 

REFERENCES 

Branner, J. C., 1910a, The geology and top<)graphy of the Serra 

do Jacobina, State of Bahia, Brazil: Am. Jour. Sci., v. 30, 

p. 385-392. 

--- 1910b, 'l'he Tombador escarpment in the State of Bahia, 

Brazil: Am. Jour. Sci., v. 30, p. 335-343. 

--- 1911, The geography of northeastHrn Bahia, Brazil : 

Royal Geog. Soc. Jour., p.139-152 and 251)-269. 

Derby, 0. A., 1906, The Serra do Espinhaco: Jour. Geology, v. 

14, no. 3, p. 374-401. 

Kegel, W., 1959, Estudos Geologicos na zona Central da Bahia: 

Rio de Janeiro, Div. de Geologia e Mineral do D.N.P.M. Bull. 

198,35 p. 

Rimann, E. T., 1917, A Serie Bambui : Anais da Escola de Minas, 

Ouro Pre to, Minas Gerais, Brasil, Bull. 15. 

Oliveira, A. I., and Leonardos, 0. H., 1943, Geologia do Brasil: 

2d ed., Rio de Janeiro, Ministerio da A!~ricultura, 813 p. 

363. RESULTS OF INVESTIGATIONS FOR URANIUM IN THE TUCANO BASIN, BAHIA, BRAZIL 

By D. D. HAYNES and J. J. MAT't;KO, Bowling .Green, Ky., and Quetta, Pakistan 

Work llon.e on behalf of the U.S. Atomic Energy Commission in cooperation with the Brazilian Natioru~l Atomic Energy 

Commission 

The town of Jorro is the center for uranium exploration in the Tucano basin, Bahia, northeast Brazil. It 

lies about 220 km, airline distance, north of Salvador, 

the cn.pita.l of the State. . 

Exploration for uranium in the Tucano basin has 

been carried on since January 1957. vVork in the basin 

wn.s begun because of a.n occurrence of radioactive fossil 

bones reported to be from south of .J orro on the Ita.picuru River (Price n.nd Haynes, unpublished data, 1956) 

and because deposits of therma.l springs 1n the basin 

were also radioactive. 

The basin is a north-trending graben valley containin.g mostly clastic sedimentary rocks ·t?f Jurassic ( ~), 

Cretaceous, and Tertiary ages. It is bordered on the 

south by Tertiary sedimentary rocks and a few granite 

inliers of Precambrian age, on the east and west by 

crystalline rocks of Silurian age, and on the north by 

granite and granite-gneiss of Precambrian age. 
D-214 GEOLOGICAL SURVEY RESEARCH 1 9 6 1 

In a study of well logs, well cuttings, and core-chip 

samples, obtained by Petr6leo Brasileiro, S.A. (Petrobras) Haynes located 3 uranium-bearing samples from 

the 1626.1- to 1631.0-meter interval of the Petrobras 

Macaco I well at J orro, Bahia. Radiometric and chemical analyses of splits of the 3 samples showed that the 

· equivalent-uranium ( eU30s) content ranges from 0.083 

to 0.096 percent, and that the uranium oxide (U30 8 ) 

content ranges from 0.096 to 0.142 percent. The 

uranium-bea.ring zone occurs in the Sergi formation of 

Early Cretaceous age .. 

Near the west edge of the Tucano basin the Sergi 

formation is structurally higher than at J orro _because 

of faulting and tilting of the beds. Reconnaissance 

in this area led to the discovery of an otitcrop of radioactive sandstone near Po~o Redondo; about 11 miles 

southwest of J orro. ·An exploratory hole, Po~o Redondo 

I, drilled to a depth of 18.5 meters, penetrated several 

zones of radioactive sandstone. Selected samples from 

this hole contain as much as 0.20 percent eU30 8 • The 

greatest uranium content of any of the samples analyzed 

chemically was 0.066 percent U30s. 

The uraniferous samples from the P Re--I hole have 

the same general appearance and mineralogy as the 

samples from the Macaco I well. The P Re-I samples 

contain coffinite and montroseite as well as manganese 

oxide, pyrite, chalcopyrite, zircon, carbonized wood, 

and radioactive barite. The radioactive barite shows 

strong alpha-particle radiation, probably caused by the 

presence ·of radium in the barite structure (Stern and 

Stieff, 1959). 

REFERENCES 

Andrade, Jr., Jose F. de, 1926, Agua Thermo-mineraes do 

Valle do rio Itapicuru, Estado da Bahia, Brasil: Serv. 

Geol. Miner., Bull. 17. 

Stern, T. W., and Stieff, L. R., 1959, Radium-uranium equilibrium and radium-uranium ages of some secondary minerals: U.S. Geol. Survey Prof. Paper 320, pt. 13, p. 154. 

364. THORIUM AND RARE EARTHS IN THE POCOS DE CALDAS ZIRCONIUM DISTRICT, BRAZIL 

By HELM'QTH WEDow, JR., Knoxville, Tenn. 

Work done in cooperation with the U.S .. Atomic Energy Commission 

An airborne radioactivity survey of the Po~os de 

Caldas Plateau in the States of Minas Gerais and Sao 

Paulo, Brazil, in 1953 recorded an intense anomaly at 

Morro do Ferro, near the geographic center of the plateau (fig. 364.1). The source of the anomalous radiation at Morro do Ferro proved to be one of the most unusual high-grade thorium and rare-earth deposits discovered in recent years. The deposit lies almost in the 

middle of the long-known Po~os de Caldas zirconium 

district (Teixeira, 1936) where the ores consist of caldasite (an intimate mixture of zircon and baddeleyite) in. 

which uFanium was noted during the early 1950's and 

recently investigated by Tolbert (1958). Subsequent 

to the study of the uraniferous zirconium deposits, the 

U.S. Geological Survey, in collaboration with the Brazilian Conselho N acional de Pesquisas and the Departamento N acional da Produ~a·o Mineral, and the Cia. 

Geral de Minas, owner of the deposit, undertook a surface exploration program to determine the grade and 

tonnage of material at Morro do Ferro that might be 

developed by large-scale openpit mining methods. 

The country rock at l\forro do Ferro is deeply decomposed and cannot be identified with certainty, but it is 

believed that bedrock is syenite-phonolite, typical of 

the alkalic igneous rock that characterizes the Po~os de 

Caldas Plateau. At l\forro do Ferro a magnetite stockwork in which the major veins trend N. 50° to 60° W. 

and dip 50° to 85° NE. cuts the syenite-phonolite rocks 

(fig. 364.1). The stockwork probably represents a late 

stage in the cycle of alkaline intrusion. 

The mineralizing solutions containing thorium and 

r~ire-earth elements followed the emplacement of magnetite, and enriched the highly fractur~d rocks and the 

borders of son1e of the magnetite veins. Nothing is 

known of the age relations between the thorium and 

rare-earth and the zirconium-uranium suites of the 

district, as the two types are completely separated 

physically; the Morro do Ferro occurrence of thorium 

and rare earths a.ppears to be unique for the district. 

Subsequent deep weathe~·ing, typical of the district as a 

whole and reminiscent 'of laterization, has altered both 

the thorium deposit and the surrounding country rock 

to a compact clayey saprolite. The depth of this 

·weathering extends to more than 100 meters. The 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 2H3-435 D-215 

EXPLANATION 

§m 

Zone of intense radioactivity 

(>LO percent eTh02) 

Approximate ~ positions of 

prominent magnetite veins 

-··=® 

Approximate positions of trenches 

excavated by Cia. Geral de Minas 

[2] 

Zone of moderate radioactivity 

(0.1-1.0 percent eTh02) 

D 

Unenriched syenite-phonolite 

country rock 

>- Ad it driven by the Departamento 

Nacional da Produc;iio Mineral 

,' , , Belo Horizonte 1 1'..,0 

M A TO .r, '--'', I- ----.... • ~~ f'-,0 ," I -'8.-.,;~ GROSSO 11 1 MINAS GERAIS ,t ~~~ 1

' P090S DE CALDAS ,.-.c._ --, PLATEAU .1

1 o- ..0 ,•MORRO DO_ FJ::!tM kq: "'~o. \ , _-··dUO DE JA~·- ?o '-· ,-' 

500 KM 

FmunE 364.1-Thorium at~d rare earths at Morro do Ferro, 

P~os de Caldas zirconium district, Brazil. 

amount of eluvial or secondary chemical enrichment of 

the thori urn and rare earths by weathering has not yet 

been established, although available data suggest that 

some such enrichment has taken place. Eluvial concentrations of magnetite as much as 2· meters thick have 

locally masked parts of the deposit. 

The exploration program to determine the extent of 

the material at Morro do Ferro that might be amenable to openpit mining consisted of preliminary scintillation-counter surveys followed by the excavation of 

about 600 m of trenches and numerous test pits and 

gamma-ray logging of deep auger holes drilled by the 

Departamento N acional da Produ~ao Mineral. More 

than 500 channel samples, taken from the trenches and 

test pits, were analyzed radiometrically for equivalent 

thoria ( eTh02 ) ; selected samples and composite sainples were analyzed chemically for total rare-earth 

oxides and thoria (Th02 ). An example of the relation 

of eTh02 to total rare-earth oxides in a trench is given 

in figure 364.2; the scintillation -counter traverse over 

the trench line prior to excavation is also presented. 

Spectrographic tests and mineralogic studies were also 

made of selected samples. The exploration at Morro 

do Ferro showed a roughly lenticular zone with a length 

of about 500 m and a maximum width of about 130 m 

in which the altered alkalic rocks average about 1 percent eTh0 2 ; this is surrounded by a halo several tens of 

meters broad of weaker but still significantly (0.1 to 1.0 

percent eTh02 ) radioactive material. Radioactivity 

measurements in test pits and deep auger holes show 

that !:)trong radioactivity extends to a depth of at least 

several meters. l\{easurements in deeper auger holes 

and examination of an adit driven in the center of the 

deposit by the Departamento Nacional da Produ~ao 

Mineral (fig. 364.1) indicate that the zone of altered 

rock impregnated with radioactive minerals extends to 

depths of several tens of meters, but that at such depth 

the radioactivity is more spotty or pockety. 

60 

---'--__j 

METERS 

..I!'IGURE 364.2.-Scintillation-counter traverse and relation of 

equivalent thoria to total rare-earth oxides in composite 

samples taken along trench A. 
D-216 GEOLOGICAL SURVEY RESEARCH 1 9 61 

Assays on tmconcentrated material show a range of 

0.13 to 3.77 percent eTh02 and 1.5 to 21.13 percent total 

rare-earth oxides. Mineralogic study indicates that 

much of the thorium is present as thorogummite. 

Thorium also occurs in allanite, which has generally 

been altered by weathering to a reddish-brown claylike 

desilicated material similar to that described by Watson 

(1917) from pegmatites in the Piedmont of Virginia. 

The rare-earth elements occur chiefly in the allanite and 

its weathering products and in the rare-earth fluocarbonate, bastnaesite. The uranium content of the samples is low, generally in the O.OOX to O.OX percent 

. range. The uranium is believed to occur in zircon, 

which is present in trace amounts in the weathered rock 

and which probably was an accessory mineral in the 

original syenitic country rock. 

Reserve estimates of the shallower portions of the 

central highgrade lenticula.r area indicate that 60 to 70 

percent of the area contains material averaging more 

than 1 percent Th02 and more than 5 percent total 

mre-earth oxides. 

REFERENCES 

Teixeira, E. A., 1936, Zirconio no planalto. de PO(;os de Caldas, 

Estados de Sao Paulo e Minas Geraes, Brasil: Brazil, 

Servi!:O Fomento Produ~1io Mineral, Avulso, no. 15, 19 p. 

Tolbert, G. E., 1958, The uraniferous zirconium deposits of the 

P~os de Caldas Plateau, Brazil: (in English) Engenharia 

Minerac1io e Metalurgia, v. 27, nos. 161 and 162, Rio de 

Janeiro. 

Watson, T. L., 1917, Weathering of allanite: Geol. Soc. America 

Bull., v. 28, p. 463-500. 

365. VEGETATION-FREE ZONE ON DRY MANGROVE COASTS 

By F. R. FosBERG, Washington, D.C. 

Aerial photographs of the mangrove swamps of 

southern Ecuador, especially those on Puna Island, at 

the mouth of the Rio Guayas, show curious, apparently 

bare, flat areas between the mangroves and higher 

ground. No vegetation is discernible on good quality 

photographs of these flats, which are sharply set off 

from the mangrove forest. There is no apparent geological explanation of this pattern. 

Similar areas, even more extensive, are found on the 

delta of the Rio Villaneuva, at the southern end of the 

Gulf of Fonseca, northwest Nicaragua. They show up 

very well on aerial photographs and were observed from 

the air in 1958. Here the mangroves are found along 

the complex tidal channels but not on the flats between 

them, which have no vegetation at all but are separated 

from the gulf by a vegetated beach ridge. The bare 

areas both here and on Puna Island generally photograph white, except for some gray patches that apparently are slightly lower and possibly were wet from 

the tide at the time of the photographing. 

Several flights along the coast of Queensland, Australia, north of Brisbane, showed what is apparently 

the same phenomenon as a rather consistent feature of 

the mangrove swamps that line estuaries and lagoons. 

A well-defined zone of bare fiats lies between the mangrove and higher grow1d in most places (fig. 365.1). 

Tidal channels in these fiats are marked by mangroves. 

A short opporttmity to observe this phenomenon on 

the grotmd was afforded at the port of Gladstone, 

Queensland. Here the bare areas consist of a fine gray 

sand, completely flat and dry at the time of observation, 

but are obviously covered by the highest tides. A wet 

tidal channel on one side was lined by small mangroves. 

In moist spots slightly lower than the fiats were a few 

scattered plants of Suaeda, a widespread genus of 

halophytic herbs. Flats at a somewhat higher level 

than the sandy fiats under consideration were covered 

FIGURE 365.1.-Aerial view of mangrove swamp south of 

Queensland, Australia. White area is vegetation-free zone. 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 2{}3-435 D-217 

by SlJOrobohts rvi'rginicus, a short dense grass found in 

sn.ndy saline places t.hroughout the tropics. 

The phenomena described above are strikingly at 

variance with the pattern in mangrove swamps observed by the writer along many other tropical coasts, 

including ~{alaya, Sumatra, the Philippines, Thailand, 

the R.yukyu Islands, ~1icronesia, Fiji, New Zealanrl, 

liawaii, New Guinea, the south coast of "Vest Africa, 

Florida, and the Caribbean, and on aerial photographs 

of many other places. On photographs of northern 

Ecuador, for example, nothing of this sort was seen. 

The swamp forest there impinges directly on the higher 

ground. 

The three areas where such bare fiats were noted 

have hYo features in common: a very large tide range 

a,nd a dry, or at least seasona.lly dry, climate. The 

~enern.l vegetation away from the coast in each area 

is deciduous or sclerophyllous woodland, forest or 

savanna, indicating a dry climate. Rainfall figures 

show 1t strongly seasonal occurrence and either less than 

1,000 mm mean annual rainfall, or a very severe dry 

season, ''"ith some months having no rain at all. 

T11ble 3()5.1 shows tide ranges, mean annual rainfall, 

number of months in wet season with total wet season 

rainfall, and number of months in dry season (dry 

months are those with less than 75 mm of rain, an 

arbitrary figure), with total rain in dry season, for a 

selection of localities where mn.ngrove swamps have 

been observed, or for the nearest localities where tide 

n.nd rainfall data are available. (For example, as no 

da,bt were found for Puna Island nor for the mouth 

of the R.io Villanueva, Guayaquil is given for the 

former, and La Union and Nacaome for the latter.) 

The .first four places listed in 'table 365.1 are those having a vegetation-free zone. It will be seen that for 

Gladstone and Guayaquil the climate is generally dry, 

ttS well as seasona.lly so, whereas the Gulf of Fonseca 

n.ren, (La Union and Nacaome) has a high tota.lrainfn11 

but nn extremely severe dry season. 

The last 10 stations listed in table 3()5.1 are known 

not· to have a vegetation-free zone back of the mangroves. They have various combinations of tide ranges 

and ra.infall regimes, but none has at the same time an 

extTeme t.ide rn.nge and dry or seasonally very dry 

eli mate. 

It is suggested that the brtre zone described above is 

the area inundated by high spring tides, occurring only 

during a, short period each month, and dried out, with 

resulting concentration of sa.It, between inundations. 

r~"his oscillation betwee.n inundation and extreme dryness, a.nd especia.lly the concentration of salt during 

dry seasons .in periods between spring tides, very prob604493 o--61--15 

TABLE 365.1.-Tide ranges and rainfall data for selected man- grove areas 

Locality 

Tide range (in 

meters) 1 

Mean Diurnal .S 

l5. 

00 

Rainfall ~~~:S) in milliNumber of months 

and rainfall 

Annual I---.,-----

Wet Dry 

----------1-----------------

Gladstone (Queensland) ________ 2. 28 2. 9fi 972 4 579 28 393 

Guayaquil (Ecuador) ___________ 3. 29 -------- 3. 98 970 4 862 cg 103 

La Union (Salvador) ___ -------- 2.46 -------- 3. 04: 2111 6 2016 3 6 95 

Nacaomc (Honduras) ___________ (6) -------- ----··- 1285 7 1240 c 5 47 

Singapore. _____ ---------------_ 1. 67 2. 2/i 2375 12 2375 co 

Bucnavcntura (Colombia) ______ 3.17 3. 9a 7128 12 7128 co 

Greytown (Nicaragua) ______ :~- . 21 .3H 6588 12 6~ co 

lllncficlds (Nicaragua) __________ . 21 .30 3200 11 3172 q 28 

Turbo (Colombia)__ ____________ .23 .30 2583 10 2489 c 2 94 

Manila (Philippines)_---------- ------ 1.00 ----··- 2(,50 7 1900 c 5 94 

Miami (Florida) ________________ . 76 . 91 1493 7 1165 c 5 305 

Cienfuegos (Cuba) _____________ .Zl .3a 1055 6 !i73 C6 183 

Cartagena (Colombia) __________ . 21 .3:J 929 5 787 q 142 

Barranquilla (Colombia) _______ (6) 6.60 (6) 747 5 606 c 7' 141 

1 Tide ranges arc taken from U.S. Coast and Geodetic Survey Tide Tables. Central and Western Pacific Ocean and Indian 1955. 1-a63, 1954. America, East Coast, 

1958. 1-271, [1957]. America, West Coast, 1957. 1-:~26, 1956. 

2 Rainfall data adapted from Climatic Averages Australia. 

3 Rainfall data from Koppen, W. and Geiger, R., Handbuch der Klimatologie, 1930-

1939. 

c Rainfall data supplied by U.S. Weather Bureau, Washington, D.C. 

6 Inland locality. 

6 Irregular. 

ably exceeds the tolerance of even such halophytes as 

mangroves and various salt' n1arsh plants. Some of 

those plants can tolerate pure sea water with no inconvenience, though their striking zonation indicates 

sensitivity to differences in salinity. It is probable that 

no available pl~nt species have been able to develop 

adaptions to the augmented salt concentration brought 

about by evaporation over much longer periods than 

daily or half-daily fluctuations. 

Flats perhaps comparable to these were seen from 

the air by the writer along certain desert coasts, such 

as the Caribbean coast of the Guajira Peninsula, the 

head of the Gulf of California, and Persian Gulf coast 

of Saudi Arabia. No mangroves are associated with 

them except for a slight development in a few places 

along lagoons on the Guajira Peninsula. In Saudi 

Arabia, ne~tr Dharan, ground exatnination showed that 

these fiats are extremely saline. They represent the 

upper limit of wetting of sandy soil by grotmd water 

extending landward from the sea, the loose dry sand 

having been blown away. They have no vegetation at 

all. In these desert areas tide ranges from slight in 

the Caribbean to rnore than 7 mteters in the Gulf of 

California. All have extreme evaporation in common, 
D-218 GEOLOGICAL SURVEY RESEARCH 1 9 61 

however, which would result in the concentration of 

salt at the surface of the ground. Thus, the underlying 

reason for the lack of vegetation may be the same in 

these desert areas and in the zones back of the mangrove 

swamps discussed above. 

If the above interpretation is correct, it will enable 

the photo-interpreter to recognize a special class of 

vegetation-free areas resulting from the combination 

of an extreme tidal range and a dry climate and not 

from anomalies in the underlying rock. 

366. POLYGONAL FEATURES ON BEDROCK, NORTH GREENLAND 

By WILLIAM E. DAVIES, Washington, D.C. 

Work done in coope1·ation with U.S. Air Force Cambridge Research Laboratories 

Polygons related to extreme freeze and thaw cycles 

are widespread at BrS!inlund Fjord in North Greenland. 

These features ·were examined during three visits to the 

region since 1956. 

Br0nlund Fjord extends westward for about 15 miles 

from the north side of Independence Fjord. The fjord 

is bordered by gently sloping and terraced plains except on the north where cliffs over 2,200 feet high form 

the shore. The fjord heads in an area of broad, flatfloored interconnecting vaJleys. The valleys are 

bounded by cliffs and steep slopes that border a plateau 

at an altitude of 2,900 to 4,000 feet. 

In the BrS!Snlm1d Fjord area the rocks are mostly 

sedimentary and are Precambrian to Middle Ordovician 

in age. Some diabase sills are present (Troelson, 1949). 

The rocks have a regional dip of 2° to 3° to the northeast. A series of small, parallel, nearly vertical faults 

trends west along Br¢nlund Fjord and adjacent valleys. 

Frost polygons in bedrock are prominent along the 

south slope of KS!ilen, a hill 4 miles east of the mouth of 

Br¢nlund Fjord, and on nearly level gr01md on the 

south side of the fjord near its west end. The patterned 

areas at these .two places are about 21;2 to 3 miles long 

and % mile wide. On the south side of KS!ilen the polygons are in a massive gray dolomite in the middle part 

of the Thule group (late Precambrian). They are 30 

to 60 feet long on a side and are rectangular in plan. 

The edges are dolomite rubble in ridges 6 to 12 inches 

high (fig. 366.1). The area of rubble along the edge 

of the polygons is about 2 feet wide. Bedrock of the 

central part of the polygons extends beneath the rubble, 

but is interrupted by fracture zones 2 to 6 inches wide 

bordering the polygons. The inner parts of the polygons consist of bedrock having a flat surface. In most 

of the area, this surface has been planed and polished 

by glaciers. The bedrock areas in which the polygons 

occur are bordered by areas of gravel from 2 to over 10 

feet thick. The pattern of the polygons continues from 

bedrock into gravel without change. In gravel, however, the polygon boundaries are trenches 6 inches deep 

and 2 feet wide. Permanently frozen ground in gravel 

adjacent to the bedrock is 24 to 30 inches below the 

surface. In the fracture zone in bedrock, excavations 

to a depth of 3 feet did not encounter ice. 

Eigil Knuth brought to the author's attention a different form of bedrock polygons in the area near the 

west end of BrS!inlund Fjord (fig. 366.2). These polygons are in slabby gray dolomite in the middle part of 

the Thule group. The polygons are rectangular in 

plan, 25 to 30 feet long on a side, and consist of slabs of 

rock 5 to 7 feet wide, up to 10 feet long, and a foot 

thick that have been heaved upwards away from the 

underlying rock. The slabs form ridges that are about 

4 feet high and have a triangular section. Fracturing 

FIGURE 366.1.-Rubble ridge along polygon edges in bedrock, 

south side of K¢len, Br¢nlund Fjord, North Greenland. 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-219 

in bedrock along the edges of the polygons is in a zone 

6 to 12 inches wide and is similar to that in the poly-

. gons at K~len. The surface in the center of the polygons is flat and was smoothed by glacial erosion previous to the development of the polygons. Limestone 

in the center of the polygons has been fractured slighty, 

and at places the rock is broken into large slabs. In 

gross features the raised slabs resemble those described 

by Yardley (1951) in the Northwest Territories, Canada, but the separation of the slabs from the under-

·lying rock is apparently unique in Greenland. 

Jointing influences 'development of the polygons to 

some extent. In both areas of patterned ground a conspicuous set of joints trends north. The east and west 

sides of the polygons apparently follow fractures. 

Bedrock polygons probably form as a result of frost 

action in a way similar to that for polygons in unconsolidated materials. Well-developed partings along 

bedding planes and small cavities and pores in the rock 

contain small quantities of water that freeze to form 

ice wedges along joints and fractures. The narrow 

width of the fracture zone along the edges of the polygons and the relatively large ridges of rubble above the 

joints and fractures indicate considerable working and 

vertical movement of material by freezing and thawing. 

The slab heaving along the edges of polygons at the 

locality near the west end of the fjord probably originated from a shallow zone of intense frost action 

along bedding planes. 

REFERENCES 

Troelsen, J. C., 1949, Contributions to the geology of the area 

round Jj1Srgen Br¢nlunds Fjord, Peary Land: Medd. om 

Gr¢nland, v.149, no. 2, p. 9-19. 

Yardley, D. H., 1951, Frost-thrusting in the Northwest Territories: Jour. Geology, v. 59, no. 1, p. 65--{)9. 

FIGURE 366.2.-Aerial view of bedrock polygons near west end 

of Br¢nlund Fjord, North Greenland. Darker area is gravel 

containing polygons having depressed edges. Other polygons 

have raised edges. 

367. CAVE DEPOSITS OF PHOSPHATE ROCK IN CENTRAL JAVA, INDONESIA 

By RoBERT F. JoHNSON and RAB. SuKAMTO/ Bandung, Indonesia 

An investigation o£ the phosphate-rock deposits of 

Indonesia was started in 1959 by the Djawatan Geologi 

in cooperation with the U.S. Geological Survey under 

the auspices of the International Cooperation Administration to determine the quantity and quality of phosphate rock that may be available as raw material for a 

superphosphate fertilizer plant. 

Known deposits of phosphate rock on Java are in 

limestone terrane and commonly occur in caves. The 

phosphate rock is formed by chemical reaction between 

phosphoric acid, derived from the excreta of bats, and 

the limestone floors of the caves. Caves near Adjibarang and Sukolilo in central Java (fig. 367.1) are 

described in this report. 

1 Djawatan Geologl, Indonesia 

Steep-floored caves near Adjibarang have developed 

in limestone beds of late Miocene age ( C.E.A. Harloff, 

written communication, 1932) that strike nearly east 

and dip 30° to 60° north. Cave breccia, composed of 

limestone fragments and soil, accumulates in the deepest 

part of the caves where it is covered in many caves by 

soil and clay as much as 4 meters deep. A vertical section through the cave filling commonly shows a barren 

soil layer of varying thickness underlain by 1 to 2 

meters of soil containing a skeletal network of phosphate-rock veinlets that contain as much as 15 percent 

P 20 5 • Below this is cave breccia of limestone fragments 

cemented and partially replaced by phosphate rock. 

The grade of this material is as high as 32 percent P 2 0 5 • 

The limestone floor of the cave is also replaced by a 
D-220 GEOLOGICAL SURVEY RESEARCH 19 61 

EXPLANATION 

Known phosphate • area 

fill 

Probable phosphate area 

X 

Phosphate· areas described 

in this report 

': 0 

0 N 

Karimundjawa 

r 

FIGURE 367.1.-Index map of Java showing the distribution of phosphate deposits. 

thin layer of hard phosphate rock, generally less than 

20 em thick. 

The phosphate rock is creamy, brown, or nearly black 

and has a waxy luster. It commonly shows contorted 

banding enclosing small limestone fragments and 

roughly parallel to larger limestone blocks or to the 

walls and floor of the cave. The rock has a high 

porosity owing to the leaching of unreplaced limestone 

fragments. 

Surface deposits of phosphate rock occurring in or 

adjacent to the limestone beds are believed to mark the 

sites of former caves that have been destroyed by 

erosion. At these places, phosphate rock, which is less 

soluble than the limestone, occurs as a concentration of 

phosphate-rich fragments in soil. Some of the surface 

deposits are in slumped areas that seem to be collapsed 

caves and these deposits contain phosphate rock that 

cements breccia identical in appearance to cave breccia. 

Of 21 caves and surface deposits of phosphate rock 

visited near A<J.jibarang, only 6 contained possible reserves of 100 tons or more. Three caves were nearly 

inaccessible and thre.e others were blocked by soil 

washed in from recently deforested slopes; local residents report phosphate rock in the blocked caves. 

One cave, Gua Serwiti, possibly contains 20,000 tons of 

low-grade phosphate rock. It is estimated that about 

7,000 tons of this phosphate rock would be suita.ble for 

the manufacture of superphosphate. Residents report 

that more than 10,000 tons of phosphate rock has been 

produced, largely from Gua Serwiti. The rock is 

mined with hand tools and is hand carried as much as 

2 kilometers to the nearest road. 

Sukolilo is 60 kilometers east of · Semarang, on the 

northern edge of a range of hills that are underlain 

by massive limestone beds of Miocene age. The limestone is folded, but the regional dip is to the north; 

the maximum dip is about 20°. Caves develop down 

dip in the limestone, but in contrast to those in the 

Adjibarang area, they have gently sloping floors. 

More than 30 caves and surface deposits of phosphate 

rock were examined and 30 additional caves were reported in .an area of about 70 square kilometers at the 

western end of the hills. The caves range in size 

from mere overhangs on limestone cliffs to caves more 

than 200 meters long and 4 meters wide. Rooms in 

some caves are as much as 20 meters in diameter. 

The phosphate rock occurs as skeletal networks in 

soil or as cement in cave breccia similar to that at 

Adjibarang. About half the deposits visited contain 

from 70 to 2,000 tons each of phosphate rock having 

from 7 ·to 36 percent· P20 5 • Locally abundant aluminum and iron phosphate would have to be removed before the material could be used for the manufacture 

of superphosphate. As much as 4 meters of soil covers 

the phosphate rock in some caves. 

I. M. Adnan (written communication, 1960) points· 

out the following major difficulties in utilizing phosphate rock from these cave deposits: (a) The caves 

are small and widely scattered, and mining and transportation costs will be high ; (b) most deposits .are too 

low grade to be used directly as raw material and will 

have to be upgraded by hand sorting and washing; 

(c) impurities in the phosphate rock, such as aluminum and iron phosphates, and fluorine will require 

special methods of treatment and close control during 

mini)lg, thus increasing costs. 

. It is doubtful that there are sufficient reserves of 

phosphate rock for sustained production of superphos-

·' 
SHORT PAPERS IN TliE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 2 9 3-4 3 5 D-221 

ph ate. The phosphate rock has been used as· natural 

rock fertilizer; this may remain its most economic use. 

If phosphate rock were imported for the fertilizer 

plant, the foreign supplies of phosphate rock probably 

could be supplemented by the material of suitable qualit:y that has been found locally. 

368. PACHUCA MINING DISTRICT, HIDALGO, MEXICO 

By ARTURO R. GEYNE, CARL FRIEs, JR., KENNETH SEGERSTROM, RoBERT F. BLACK, and IvAN F. WILSON 

Wo1·1c clone muter a1t81Jices of the International Cooperation Administration in cooperation with the Oompaiiia de Real del 

:Monte y Pach1wa and the Institu,to de Geologia de la Universidad Nacional de Mexico 

The Pachuca-R.eal del Monte mining district has 

been one of the prinpical silver-producing camps of the 

world for n.bout 430 years. It has yielded more than 

1.2 billion Troy ounces of fi~1e silver and 6.2 million 

Troy ounces of fine gold, worth roughly 1.3 billion 

dollars n.t 1960 prices. This a1nount is about 6 percent 

of the silver produced in the world since the early 

part of the 16th centu_ry. In 1959, the district produced 6 million Troy ounces of silver, accounting for 

13.7 percent of l\1exico's production and 3 percent of 

the world production. It is the fourth largest silverproducing district in the world, being surpassed only 

by the Coeur d'Alene, Cerro de Pasco, and United ICeno 

Ifill districts in the United States, Peru, and Canada, 

respectively. 

The base1nent rocks in the Pachuca district are 

strongly folded and deeply eroded maritie formations 

of l\1esozoic age, which trend north-northwest. These 

a.re overlain unconformably by a pile of Tertiary. volcanic rocks, which form a west-northwesterly trending 

mounbtin range named the Sierra de Pachuca. During 

late l\1iocene time the Tertiary volcanic pile began to 

sink n.nd was broken by several westerly trending highangle faults.. In latest l\1iocene and early Pliocene 

time several groups of nearly east-west dikes were intruded, son1.e of which are traceable for more tha.n 10 

kilometers. Following dike emplacement, normal 

faulting became very active 11nd ·w·idespread, producing· 

a series of subparallel, rhombic blocks. The longest 

faults have been traced for at least 10 kilometers, and 

the nHtximum throw is about 450 n1eters. Late in this 

period of structural deformation, probably near middle Pliocene time, a group of north-south s~eeply dipping fractures and sma.ll faults formed in the eastern 

Rea.] del l\1onte half of the district. These were produced either by gentle arching along a nearly northsouth n,xis, or by compression frmn the north against 

a convex buttress lying in the southern part of the 

district. 

~1ineralization began in 1niddle Pliocene time very 

shortly after formation of the north-south fraeture system. The first vein minerals deposited were mainly 

quartz and pyrite, with calcite and rhodonitebustamite abundant locally. In parts of the district 

these minerals also replaced the immediate wall rocks 

and incl~1sions in the veins to a minor degree. The 

qua,rtz, pyrite, and other gangue 1ninerals were accompanied by, and partly followed by, the deposition of 

sphalerite, galena, and chalcopyrite in small quantities. 

Silver mineralization mainly followed that of the base 

sulfides but in places took place simultaneously with the 

latest sulfides and with late. calcite and quartz. The 

principal silver minerals are acanthite and {trgentite, 

with smaller quantities of native silver, polybasite, 

miargyrite, pyrargyrite, proustite, stephanite, and 

sternbergite. Although some early vein minerals were 

locally replaced partially by the silver minerals, n1ost of 

the silver is in crustiform layers of sulfide and gangue 

minerals filling openings along the preexisting fault and 

fracture systems of the region. Fault movement during mineralization locally crushed the vein fillings and 

formed new openings to be filled. 

"\Vithin the overall areal and vertical limits of mineralization, the localization of the ore bodies appears to 

have been governed largely by minor structural 

features. "\'There the fractures and faults were even or 

regular along the strike and down the dip, the wall 

rocks were little shattered and few openings ·were produced for vein filling. Irregularities on the fracture 

walls on which fault movement occurred resulted in 

shattered zones of vrn·ied width, with many splits off 

the ma.in fault, and with numerous openings available 

for filling. ~finable ore bodies have ranged from a 

maximum width of about 40 meters in intensely 
D-222 GEOLOGICAL SURVEY RESEARCH 19 61 

shattered zones, to a minimum of about 1 meter in very 

narrow high-grade veinlets, but the average width has 

ranged mainly between 2 and 4 meters. In recent 

years, mining has been at the rate of nearly a million 

tons a year of ore averaging about 250 grams of silver 

and 1.4 grams of gold per metric ton, plus a few tenths 

of 1 percent of combined base metals. . 

The maximum cover over the tops of the highest ore 

bodies during mineralization was about 300 meters, and 

the deepest ore bodies were deposited about 1,000 meters 

below the surface. In spite of erosion after the mineralization, most of the ore bodies are still covered, although fractures, with· or without barren quartz, can 

generally be recognized where erosion is deepest. Some 

ore bodies "top" as far as 600 meters below the surface. 

The "roof" of the mineralized bodies is irregular, 

where as the bottom is more nearly uniform. This 

blanketlike form of mineralized bodies suggests a 

temperature-pressure control. 

Following mineralization, in late Pliocene or Pleistocene time, dominantly strike-slip movement occurred 

along or parallel to many of the east-west veins, crushing some of the vein material and displacing most of 

the north-south veins in the Real del Monte area where 

the two vein systems intersect. The deeper ore bodies 

have not been affected by supergene oxidation and leaching, but some of the higher ore bodies have been 

affected. 'Vhere alteration has occurred, the ore bodie~ 

have been impoverished in silver without any corresponding zone of secondary enrichment. 

369. MARINE PHOSPHORITES OF NORTH-CENTRAL MEXICO 

By CLEAVES L. RoGERs, EuGENIO TAVERA AMEZcuA, JEsus OJEDA RIVERA, ZoLTAN DE CsERNA, and RooER 

VAN VLOTEN, Washington, D.C. and Mexico, D.F. 

Work done in cooperation with Oonsejo de Recursos Naturales No Renovables under the auspices of International Cooperation Agency, Department of State 

Phosphate deposits have been mapped and sampled 

in an area of about 26,000 square km, mainly in northern Zacatecas and southern Coahuila but extending 

eastward into the States of Nuevo Loon and San Luis 

Potosi (fig. 369.1). This area includes parts of the 

Sierra Madre Oriental, which is analogous physiographically to the Rocky Mountains of the United 

States, and the Mesa Central, which resembles the Basin 

and Range province. The geology and phosphate deposits of part' of this area have been described by Rogers 

and others ( 1956) : 

The phosphorites are limited mainly to one member of 

the Upper Jurassic La Caja formation and its equivalent, the La Casita formation, and are in the lower part 

of a thick sequence of marine sedimentary rocks that 

were deposited in the Mexican geosyncline during Late 

Jurassic and Cretaceous time. The La Caja formation 

is the offshore facies and is predominantly calcareous 

siltstone, with smaller quantities of limestone, chert, 

phosphorite, and shale. The La Casita formation is 

the nearshore facies and consists mainly of gray to 

black carbonaceous shale, some conglomeratic sandstone, 

and a few layers of arenaceous coquinitic limestone. 

Some of the shale and limestone beds in the middle and 

upper parts of the La Casita formation are slightly 

phosphatic, and phosphatic rocks are moderately abundant where the La Casita interfingers with the La Caja 

formation. 

The phosphatic unit has moderate to steep dips and 

crops out in anticlines in narrow belts flanking rather 

ma~sive limestone, which forms the cores of the anticlines. In some areas the unit has been displaced by 

faults, and locally it is cut by intrusive rocks. 

The richer phosphatic beds are mainly apatite, calcite, 

and chert mixed in widely varying proportions, and are 

designated by names such as calcareous ·phosphorite, 

phosphatic limestone, and calcareous phosphatic chert. 

At many places these rocks are interbedded with calcareous siltstone and smaller amounts of shale that are 

only slightly phosphatic. 

The phosphate is a dense cryptocrystalline material 

with a concretionary· habit. Most of the phosphate is 

primary, but some material has been dissolved andre~ 

deposited, probably under diagenetic conditions. Primary phosphate forms small generally structureless 

pellets and nodules ranging in size from 0.05 mm to 

about 3 em; younger phosphate replaces fossils, forms 

rims on primary pellets and nodules, and is disseminated through the rock matrix. The phosphatic 

material is light gray, pink, light to dark brown, or 
,-

SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-223 

26or-------------------~!-Or2-o----------------------~1,0~1-o~------------------~l~O~O~o----------~ 

I 

\ 

\ • Monterrey 

Area studied "'' 

' 

1 

' 

J ---

• Parras 

I 

COAHUILA 

Concepci6n • 

del Oro 

(Rogers and 

others, 1956) 

23°~------------~-----L--------~ 

• Zacatecas 

0 10 50 100 KM 

Saltillo '~-'---

.~-'---

I 

• G6me(Farias 

\, .larlx>nera 

San Salvador I 

\ 

\ 

Gale ana • 

Monternorelos • 

NUEVO LEON 

c: 

l 

I 

( 

' 

I 

UNITED STATES 

MEXICO 

Area ~ studied 

FIGURE 869.1.-Map of Mexico showing location of the area in which phosphate deposits were studied. 
D-224 GEOLOGICAL SURVEY RESEARCH 1 9 61 

black. The color, and also a fetid odor, may depend 

upon the amount of associated hydrocarbons and iron 

oxide. In thin sections the material is generally light 

to medium dark brown and nearly isotropic. 

~ficroscopic study reveals that many pellets have a 

rounded or oval form, and a few are elongated or rodshaped; in some thin sections 1nost of the pellets can 

only be described as irregular. ~1ost pellets lack visible 

nonphosphatic nuclei, but where microfossils are 

abundant these fossils commonly appear to have been 

nuclei for the deposition of apatite; in some pellets the 

phosphate seems to have precipitated around small 

detrital quartz grains. 

The phosphate mineral is .carbon~te-fluorapatite and 

has been shown by X-ray analysis to be very similar 

to that in phosphorites of the Phosphoria formation of 

the western contenninous United States. Fluorine is 

present in a proportion equal to about 10 percent of the 

PzOs content. The uranium cm).tent ranges from 0.001 

to 0.006 percent. 

The phosphorite bed~ were deposited as predominantly chemical or biochemical sediments, containing 

little detrital material. The authors favor a chemical 

rather than a biolithic origin for the phosphate, althO\lgh the evidence is not conclusive, and both modes 

of origin may have played a part. Deposition of the 

phosphatic beds appears to have been extremely slow, 

if their thickness is compa.red with the much thicker 

tin1e-equivalent beds in the Gulf region of the United 

States, in Cuba, or in California. Macrofossils indicate 

that the depqsits formed in clear shallow waters, perhaps in the shallower parts of the neritic zone of a 

cold shallow sea. Local concentrations of phosphate 

apparently are due largely to nondeposition of clastic 

material and may have formed on ]ow submarine ridges 

that received less silty material than adjacent shallow 

basins. 

In the phosphatic unit, calcareous phosphorite contains the most phosphate and is the most abundant rock · 

type; the P20s content of this rock ranges from 15 to 

27 percent. Layers of calcareous phosphorite.range in 

thickness from less than 1 em to 2 m or more, and in 

some areas are highly lenticular.· At places, thin ]ayers 

of phosphorite alternate with siltstone in sequences as 

much as 6 m thick, and the deposits would ·be of commercial grade if the two kinds of rock could be separated. The three columna.r sections in figure 369.2 

~how the vertical distribution of calcareous phosphorite 

1n the phosphatic unit and the P 20 5 content of this unit 

EXPLANATION 

Calcareous 

-

phosphorite 

c=J 

Calcareous siltstone 

FIGURE 369.2-Columnar sections of phosphatic unit in the 

Sierra de Carbonera, Coahuila and Nuevo Leon, showing 

P205 content in percent. 

in the Sierra de Carbonera, one of the areas containing 

potentia.lly commercial deposits. 

The reserves of phosphatic rock are estimated to 

total at least 77 million metric tons averaging 18 to 19 

percent P20s, and about '76 million metric tons averao-- . b 

~ng 13 to 14 percent P205 • These figures are based on 

the results of sampling at 131 localities. Spacing of 

samples is sufficiently close to class as reasonably certain about 20 million metric tons of phosphatic rock 

(including about 13,500,000 metric tons that were reported earlier by Rogers and others, 1956) ; the remainder is classed as inferred. Recent exploration by 

private companies and individuals suggests that the 

actual reserves may be considerably greater. Large 

quantities of phosphatic rock contain 10 to 12 percent 

P 20s, but these are not considered in the reserve 

estimates. 

The Comisi6n de Fomento Minero constructed a pilot 

plant at Saltillo in 1957 to beneficiate the phosphatic 

rock and, using a calcination process, has been successful in raising the grade of the phosphatic material to 

about 30 percent P20s, which is sufficient for the manufacture of superphosphates by the sulfuric acid 

process. 

REFERENCE 

Rogers, C. L., de Cserna, Zoltan, Tavera, Eugenio, and Ulloa, 

Salvador, 1956, General geology and phosphate deposits of 

Concepcfon del Oro district, Zacatecas, Mexico: U.S. Geol. 

Survey Bull. 1037-A, 102 p. 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 2 9 3-4 3 fi D-225 

370. DECELERATION OF EROSION AT PAR1CUTIN, MEXICO 

By KENNETH SEGERSTROM, Santiago, Chile 

The eruption of Paricutin volcano, which lasted from 

1943 to 1952, is one of the best documented volcanic 

episodes in history. A principal effect of ash fall from 

Padcutin was interruption of the erosion cycle, caused 

by the burial and destruction of vegetation and the 

bhtnketing of slopes by the easily erodable, abrasive ash 

(Segerstrom, 1950). ~1ost of the ash fell during the 

first 2 years, and the highest rates of erosion were attabled during the rainy seasons of 1943 and 1944 (fig. 

370.1). Deceleration of the. abnormally high erosion 

rate bega.n after the 1944 rainy season, although eruption of pyrocla.stic material and lava continued for 

7lj2 more years. After the ash falls ceased in 1952, the 

deceleration o:f erosion was even more evident than before (fig. 370.1). Observations were made by the 

author in the volca.no area in February 1957, (Segerst.rom, 1960), and again in December 1960. 

In 1960 the depth of a conspicuous stream channel 4 

km east of the volcano (fig. 370.2) was only 2.46 m below 

the contact between ash from Paricutin and the preexisting soil, as compared with 2.30 m at the same place 

in February 1957 (Segerstrom, 1960, p. 10, locality 8). 

llerc in 1950 the drainage from the east side of the 

Par.lcutin lava. field had breached a former watershed 

divide in deeply weathered soil. Similar examples of 

I 

I 

I 

' ) ,, 

I I I I 

I I 

I I 

' ' ,, 

\ 

1'\ ,-, I I I I 

I I I I I I I I I I I I I I I I ' I 

-

---

.. , ,...1 I I I I I I I I I 1 : I I I 

I I I I I I \ I I \ J \ ... , ... ~ 'J 

only slight channel deepening in nearly 4 years were 

seen at other localities. Rainfall was not measured in 

the volcano area during the 4-year period, but it is believed that precipitation was not below normal. 

At Terupicua on the north edge of the lava field, the 

surface of a fill deposit about 3 hectares in area was 6 

em higher in December 1960 than it was in February 

1957 (fig. 370.3). Similar examples of only slight incrmnents in stream deposits in nearly 4 years were also 

seen at other localities. 

It may be concluded that erosion and redeposition in 

the Paricutin area have.slowed down for two principal 

reasons : the· most vulnerable ash deposits have been 

largely stripped from the steepest slopes and from the 

main stream channels, and areas covered by ash or new 

alluvial deposits are rapidly becoming vegetated. 

In December 1960, dense stands of young trees were 

springing up in nu1Ch of the area that was forested 

before the eruption. In areas that were formerly cropland (fig. 370.2), scattered young trees, shrubs, and 

sma.ller plants were also growing in the ash, particularly 

where there was an admixture of redeposited preexisting soil or of debris from the older trees. At Ch6rotiro 

a fill deposit that partly covered the northeastern edge 

of the lava field supported a dense stand of vegetation, 

.. ,, /I I' I I I 

I I I 

I I I 

I I I I I I I I 

I I ' .. ' . ,_ I 

Rate of erosion during 1940--1960 

Inferred rate Ot erosion-assuming no eruptive activity 

Line draw~ugh peaks of the 

1940-1960 erosion curve 

~ ERUPTION, FEBRUARY 1943-FEBRUARY 1952 ~ 

1940 1945 1950 1955 1960 

FIOUitE 370.1.-Diagrammatic representation of erosion rates at Paricutin during the period 1940-60. 
D-226 

-o.5-

Line of equal ash fall in meters 

GEOLOGICAL SURVEY RESEARCH 19 61 

0 2 3 4 Kl LOM ETERS 

EXPLANATION 

~ ("·:·.:·.:.·~::.-·.::.::.-·.1 

Paricutin lava field, i960 Area formerly cropland 

FIGURE 370.2.-Map of the vicinity of Paricutin volcano. 

1945 

Place where cultivation was begun after 1943, 

showing year 
SHORT PAPERS IN THE GEOLOGW AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-227 

FIGURE 370.3.-Edge of lava field at Terupicua showing fill deposit in foreground. This locality is the same as that of 

Segerstrom, 1960, figure 9. 

including several pines as much as 15 em in diameter 

and over 3 m high. Pines, broadleaf trees, ferns and 

other plants had even taken root in narrow crevices in 

the lava. In December 1960, abundant lichens and 

scattered plants of other varieties were growing on the 

top of the Parfcutin cone and in the crater. Beaman 

(1960) described 14 vascular species found on the cone 

in September 1958, and has reported that nearly double 

that number of vascular plants were found in September 

1960 (written communication, January 18, 1961). 

Agriculture, which was interrupted locally by the 

eruption, was resumed at a few places as early as 1944. 

By 1960, crops were' sown and harvested at many places 

in the volcano area. The years when cultivation began 

are shown on figure 370.2. 

In the areas of renewed cultivation, corn is virtually 

the only crop. Cultivated areas at the east and north 

edges of the lara field are between the 0.5-m and 1-m 

lines of equal ash fall. All the areas are covered by redeposited ash containing admixtures of vegetal matter 

and preexisting soil. At the Ashuno locality, cultivation was attempted in 1960 in a wooded area in which 

large amounts of pine needles are mixed in the ash. 

The only attempts to cultivate areas of former cropland where the ash fall was greater than 0.5 m were 

made in Zirosto, about 8.5 km northwest of the volcano. 

The townspeople at that place began shoveling ash from 

garden plots in 1944, and by December 1960, between 

one-third and one-half of Zirosto had been cleared in 

this manner. 

In areas of less than 0.5 m ash fall, much of the land 

that had been cultivated before the eruption had been 

reclaimed for agriculture by 1945. Erosion of the relatively thin ash from the sides of broad valleys and its 

redeposition with admixtures of preexisting soil in the 

valley bottoms aided in the reclamation of those areas. 

Because of the deceleration of erosion and because 

of the rapidity of revegetation, early repopulation of 

the Paricutin area now seems assured, even where the 

total ash fall was more than 0.5 m. The new town of 

San Salvador Teruto, 3 km south of the cone, in December 1960 had 44 families. El Sauz, 5 km northeast 

of the cone, was another new village with several families, and 9 families lived in the ruins of San Juan 

Parangaricutiro '"here only 4 had lived in 1957. 

Zirosto had a population of 80 families in December 

1960. 

REFERENCES 

Beaman, J. H., 1960, Vascular plants on the cinder cone ot 

Parfcutin volcano in 19;)8: Rhodora, v. 62, p. 175-186. 

Fries, Carl, Jr., and Gutierrez, Celedonio, 1954, Activity of 

Parfcutin volcano during the year 1952: Am. Geophys. 

Union Trans., v. 35, p. 486-494. 

Segerstrom, Kenneth, 1950, Erosion studies at Paricutin, State 

of l\lichoacan, Mexico: U.S. Geol. Survey Bull. 965-A, p. 

1-164. 

--1960, Erosion and related phenomena at Par'lcutin in 

1957: U.S. Geol. Survey Bull. 1104--A, p. 1-18. 

Wilcox, R. E ., 1959, Some effects of recent volcanic ash falls, 

with especial reference to Alaska: U.S. Geol. Survey Bull. 

1028--N, p. 409--476. 
D-228 GEOLOGICAL SURVEY RESEARCH 1 9 6 1 

371. THE IRON FORMATION OF THE SURGHAR AND WESTERN SALT RANGES, MIANWALI DISTRICT, WEST 

PAKISTAN 

By WALTER DANILCHIK, Quetta, Pakistan 

Work done in cooperation with the Geological Survey of. Pakistan ttnder the auspices of the International Ooopemtion 

Administration 

Extensive efforts have been made to discover and 

develop a domestic source of iron ore in Pakistan in 

order to reduce expenditures for imported steel. Ironrich sedimentary rocks, which are widespread in West 

Paldstan, are now being surveyed to determine the 

feasibility of their use as low-grade ores of iron. 

Interest in the development of iron-bearing sedimentary rocks has centered in the Surghar and ·western 

Salt Ranges in the Mianwali district of 'Vest Pakistan 

(fig. 371.1), ·where an extensive iron formation is relatively accessible. The region offers abundant labor, 

rail facilities, electric power, ample water from the 

nearby Indus River, and already supports mines producing coal, salt, limestone, dolomite, and gypsum. 

In 1958, the Geological Survey of Pakistan and the 

U.S. Geological Survey began a comprehensive geological investigation of the Surghar Range as part of 

the International Cooperation Administration technical 

assistance progr::Lm in Pakistan. 

The Surghar and Salt Ranges are underla.in by a 

thick sequence of sedimentary rocks ranging in age 

from Cambrian to Quaternary. The stratigraphic sequence contains many well-defined rock units, which 

have been defined and mapped by vVynne (1880), Gee 

( 1945) , and more recently studied by Imam and Kidwai (in pressL and IGdwai (in press). M:ost of these. 

units crop out along the south and east sides of the 

Surghar Range and in the western Salt R.ange, forming 

steep escarpments that rise locally more than 3,000 feet 

above the Indus Plain. The sequence includes at least 

three major unconformities. 

The principal structures of the Surghar and western 

Salt Ranges are large, generally asymmetric, faulted 

folds roughly paralleling the ranges (fig. 371.2). The 

structure of the western part of the Surghar R.ange is 

fairly simple, but is increasingly complex toward the 

east, particularly near J(alabagh, where the effects of 

·at least three episodes of strong deformation during 

the Tertia.ry and Quaternary periods can be recognized. 

The iron-rich beds are in the upper pa'rt of the Chichali formation (the "Belemnite beds") of Neocomian 

age. They consist mostly of glauconitic sandstone having a maximum thickness of 200 feet. In the high 

elevations of the Surghar R.ange, the outcrops of the 

beds are generally continuous. In the Salt R.ange, the 

beds are discontinuous and poorly exposed. 

In the Makarwal area the iron-rich layer is mainly 

glauconite and ranges in thickness from 20 to 23 feet. 

Chemical analyses of a five-part channel sample across 

a 22-foot. bed believed to be representative of the layer 

show the following percent averages: Fe203, 45.88 ; 

Si02, 26.08; Al203, 8.13; C02, 1.9; CaO, 0.68; N a20, 

0.10; P20s, 0.52; I\:20, 2.97; loss on ignition, 12.70. 

The glauconitic layer in the vicinity of Chichali Nala 

is believed to be stratigraphically higher than the ironrich layer at Makarwal. This suggests the possibility 

of two stratigrapliically distinct iron-rich beds. 

In the eastern part of the Chichali area the iron-bearing stratum change·s from glauconitic to chamositic 

rock. North of J(uch it consists mostly of chamosite 

with some siderite and hematite. Analyese of five selected samples of this rock show the following percent 

averages: Fe20 3, 52.63; Si02, 17.00; Al203, 10.90; Ti02, 

1.10; S, 0.35; P20s, 0.46. 

Imam and IGdwai (in press) report that in the easternmost outcrops of the l(uch area the chamosite rock 

passes into a mixture of hematite and limonite. In the 

I\:alabagh area and the western Salt Range the ironbearing stratum is mostly chamosite but contains discontinuous layers of limonite, hematite, and locally 

glauconite. 

The origin of the iron-rich layer in the Chichali formation is believed to be related to the post-Neocomian 

unconformity. Over wide areas in the western Salt 

Range, much of the Chichali formation, and some of 

the underlying rock was removed during this period of 

erosion. A widespread lateritic deposit then developed 

on the erosion surface. In the Sakesar, J(uch, and 

l{alabagh areas a temporally equivalent hematitic, 

limonitic, and chamositic iron stratum developed on 

the surface of the upper part of the Chichali formation. 

Southwesterly, in the Chichali and Makarwal areas, 

the effect of the unconformity is not noticeable, and it 

is evident that the glauconitic iron stratum is a marin.e deposit. Its enrichment in iron may be related to 
• 

71000' ,...-. 

33°00' r------~ 

Qal 

32°451 ~ 

Qai 

32°30' 1-------~ 

71°15' 71°30' 71°45' 

0 5 10 MILES 

EXPLANATION 

Alluvium and rocks 

~ of Quaternary age 

!MtEM Rocks of late Tertiary age 

l'ffjj Rocks of early Tertiary age 

E3 

Outcrop of iron fonnation known to contain 29 percent Fe or more 

Dashed where continuity is doubtful 

Rocks of 

~ Mesozoic age 

(1 

~ i i Rocks of Paleozoic age /. \.~ 

~ r I Mine F ~ ; ';'.._....... " . ·'·· J>:,~ / ,) ~ ("' . - \ 

_.J 

Adapted from pis. 1 and 3 of Gee, 

1945; manuscript maps of Imam 

and Kidwai (in press); and pl. 1 

of Wynne, 1880 

FIGURE 371.1.-Generalized geologic map of the Surghar and western Salt Ranges, l\fianwali district, West Pakistan. 

'\ 

U1 

~ 

0 

::tl 

~ 

1-d 

> 1-d 

t:rl 

::tl 

U1 

z 

~ 

~ t:rl 

0 

t:rl 

0 

t"4 

0 

0 

~ 

(") 

~ ~ 

~ ~ 

::tl 

0 

t"4 

0 

0 

8 

~ ...... 

t:rl 

~ t:rl 

Sil 

> 

::tl 

j 

~ t:rl 

Cfl 

!);) 

~ 

~ 

I 

~ "'" 

~ 

~ l\:) 

co 
.4000' ~ Alluvium 

3000' 

2000' G 

Siwalik gravel 

1000' 

Sea leveiL---------~L-~~~~-G~~----~--------------~~--~~L-~~~----------~--~ G 

Mitha Khatak formation 

Sakesar 

~ limestone 

Nammal 

~ marl 

GJ B 8' Patala shale 

4000' r 

3000' 0 

Khairabad limestone 

2000' 

1000' 0 

Dhak Pass beds C £ t {I ll l l l I I Sea level' c c c c c ,..- c c Adapted from Kidwai (in press) 

2000 0 2000 4000 FEET 

EXPLANATION 

>-

}~ :::l 

0 

li;: 

c:( 

r~ 

(f) 

~ }

5i;: 

LJ.J c:( 

uo-

<zt- t-<0:: 

LJ.J LJ.J 

Lumshiwal sandstone a:: 1- u Gr § 

Chichali formation . ~ 

a:: 

~ .., u 

Baroch limestone I~ c:( 

0 I~ 

Datta formation 

0 }~ Kingriali dolomite ~ 

Iron formation 

FIGURE 371.2.-Geologic cross sections of the Surghar Range, West Pakistan, along lines A.-A' and B-B' on figure 371.1. 

~ CoAj 

0 

0 

t_:l:j 

0 

~ 

0 

0 

~ ~ 

~ ~ 

< t_:l:j 

~ 

~ 

t:;r'J 

U2 

t_:l:j 

> 

~ ...... 

tO 

Ol 

...... 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-231 

the emergence of the terrain to the east on which 

lnteritization was taking place. 

Tschoepke (unpublished data) believes the chamosite, which has R higher rntio of ferrous ii·on to ferric 

iron thnn glnneonite, wns formed in a reducing environment in sen. 'Yater deeper than that in which the glauconite originated. This interpretation precludes the 

.emergence of the Salt Range area until after the end of 

deposition of the iron stratum and requires another 

source for the clastics that were glauconitized and enriched to fo1111 the iron formation. 

Reserves of iron formation in the five areas shown on 

figure 371.1 are listed in table 371.1, together with average thicknesses of the formation that have been used in 

the calculations for each area. Continuity of the iron 

formation has been traced d~nvn-dip for more than 

1,000 feet in gorges in the Makarwal and Chichali areas, 

in the low-level adit of the :M:akarwa.l Collieries, and in 

exploratory adits on both sides of Chichali gorge. The 

reserves in these areas can be regarded as proven to a 

depth 1,500 feet down dip from the outcrop. The 

reserves listed for the Sakesar, 1\::ala.bagh, and Kuch 

areas, formerly regarded as proved, probable, and possible, may now be classed as proved on the basis of new 

information and exploration. 

REFERENCES 

Gee, E. R., 1945, The age of the Saline Series of the Punjab and 

of Kohat: India Natl. Acad. Sci. Proc., Sec. B, v. 14, pt. 6, 

p. 269-311. 

Iinam, S. A., and Kidwai, A. H., (in press), Geology of the Kuch 

and Khartop blocks of the Kalabagh iron formation, Mianwali, district, West Pakistan: Pakistan Geol. Survey Inf. 

Release. 

Kidwai, A. H., (in press), Geology of the iron formation in the 

Chichali Pass area, Mianwali and Kohat districts, West 

Pakistan : Pakistan Geol. Survey Inf. Release. 

Wynne, A. B., 1880, On the Trans-Indus extension. of the Punjab 

Salt Ranges: India Geol. Survey Mem., v. 17, pt. 2, 95 p. 

TABLE 371.1-Reserves of the iron formation in the Surghar and 

western Salt Ranges 

Average Reserves, in 

Area thickness, Dominant mineral tons of 2,000 

in feet lhs. 

----

Sakesar ______ 8 Chamosite-limonite_ I 2;700,000 

Kalabagh ____ 8 Chamosite-limonite_ 2 2,300, 000 

Kuch ________ 10 Chamosite ____ ------- 3 22, 100, 000 

Chicha}L ___ 10 Glauconite- • 99, QOO, 000 

chamosite. 

MakarwaL __ 20 Glauconite __________ • 45, 000, 000 

1 Total reserves to a depth of 600 feet below the outcrop. 

2 Total reserves to a depth of 250 feet below the outcrop. 

Source of data 

Krupp (unpublished 

data). 

Krupp (unpublished 

data). 

lmam and Kidwai 

(in press). 

Kidwai (in press). 

Danllchik and Shah 

(unpublished 

data). 

a Total reserves to depths locally 1,500 feet or more below the outcrop. 

• Proved reserves to a depth 1,500 feet below the out.crop. 

372. GROUND WATER IN THE SABI VALLEY, SOUTHERN RHODESIA 

By P. ELDON DENNis, Tucson, Ariz. 

Work done in cooperation with the International Cooperation Administration and the government of Southern Rhodesia 

The Sabi Valley (fig. 372.1) is in the extreme southeastern part of Southern Rhodesia. It is in the low 

veld at an altitude of 1,300 to 2,000 feet. The alluvial 

plain in the valiey is about 14 miles wide and 35 miles 

long, and the Sabi River maintains a remarkab~y 

straight course through the center of the plain in a 

braided channel between banks that are generally about 

a mile apart and about 15 feet above the stream bed. 

The river is the only perennial strea.m in the area, and 

its flow dwindles throughout the rainless winter season; 

the flow of the river ranges from a flood flow of about 

600,000 cfs (cubic feet per second) to about 130 cfs late 

in the rainless season. 

GROUND-WATER RESOURCES 

Ground water in usable quantities was found at one or 

more zones in all test holes in the Sabi V. alley (fig. 

372.2) . However, the water was sa.line in well 39 and 

test hole 41. It seems likely that north of this saltwater area the alluvium everywhere will yield 1,000 

gallons or more per hour to properly constructed wells. 

The records of the Southern Rhodesia Dilvision of Irrigation and Lands show that 14 dry holes were drilled 

in the area prior to the investigation. ]{ost of them 

were near the escarpment where the water table is nearly 

150 feet below land surface, and failure to obtain water 

probably resulted from inability to drill deep enough 

through beds containing cobbles and boulders, rather 

than for lack of water-bearing b~ds. The cobbles and 

boulders usually can be avoided by selecting sites between the larger mountain drainage channels and valleyward from the escarpment. A little ground water 

moves through fractures and solution channels in the 
D-232 GEOLOGICAL SURVEY RESEARCH 19 61 

2o• 

21° 

EXPLANATION 

Pleistocene and 

~ Recent alluvium 

riiTJSJ 

Cretaceous sandstone 

Jurassic 

-

basalt 

Permian 

-

Karroo system 

Upper 

-

Precambrian 

Umkondo system 

>1;,~:1 Granite 

Dolerite 

-

sills 

--------- Contact 

---------......... Fault 

0 10 20 30MI~ES 

FIGURE 372.1.-Geologic map of southeastern Southern Rhodesia. 

- Generalized from map ·by Southern Rhodesian Geological 

Survey. Rectangle in center of map shows area covered by 

figure 372.2. 

Umkondo rocks toward the Sabi Valley, but these rocks 

are thought to be an effective barrier to any eastwa.rd 

movement of the ground water in the alluvium. The 

white eolian sandstone of the upper I\:arroo system 

crops out as hills near Gumira and is well cemented in 

surface exposures. Ho·wever, the cementation may be 

surficial "case hardening," as some wells obtain their 

water from the sandstone at depths of 100 feet or less. 

The altitudes of the water surfaces in the wells are 

given on figure 372.2, and approximate contours on the 

water table have been drawn where there is sufficient 

control. It is evident that the water is moving generally southeast·ward from the Sabi River. However, 

a mound in· the water table occurs along the mountain 

front in the vi~inity of Ripisi Hot Springs from which 

water moves toward the center of the plain and then 

southward. The source of ground water which causes 

this mound is not known, but the water at Ripisi Hot 

Springs and in the mound may come up along a per.: 

meable fault zone that extends for several miles along 

the mountain front. 

Vertical movement of water in wells is caused by 

changes in the amount of water in storage and by 

changes in pressure within the aquifer. Thus far, water levels have been measured only in the dry winter 

season, and the fluctuation in 10 wells ranged from a 

few hundredths to about 2 feet. Larger fluctuations 

a~e to be expected during the rainy season. 

Two areas of recharge are suggested by the watertable map-the Sabi River and the mountain front in 

the vicinity of Ripisi Hot Springs. Presumably, recharge occurs mostly during. the summer rainy season. 

The surface materials appear to be very permeable 

everywhere except in the vlei areas where finer materials 

have been deposited by flood waters and effectively 

"puddled" by stock and wild game. Few of the tributary streams have made channels on the plain, presumably because their water seeps into the alluvium. 

It is not entirely clear where the ground water from 

the alluvium is discharged. The general southeastward gra.dient is rather steep from the 1,350-foot contour line toward the mountain escarpment in the 

vicinity of "The Gap" of the Mwangazi River. There 

is no more use of water from wells in that area than 

those in the rest of the valley, .nor is there a marked 

line of vegetation that could transpire significant 

amounts of water. Discharge through thick, perm.eable 

alluvium in "The Gap" see1ns w1likely because the 

Umzilizwi River discharges eastward to a larger river 

at an altitude as high as the altitude of the water 

table in the well near "The Gap." It is possible that 

the water discharges southward somewhere in Mozambique through a permeable fault zone bounding the 

western edge of the U mkondo rocks, but such a fault 

zone has not been detected in the rocks of the overlying 

I\:arroo system. 

The Sabi River loses about 125 cfs of water between 

Birchenough Bridge and Granite Gorge during lowflow stages, as shown by measurements made by the 

Hydrological Branch of the Division of Irrigation and 

Lands. A part of the loss is due to evaporation, but 

much of it may be ground-water recharge. 

More test holes will be necessary, particularly in the 

area between the scarp'a.nd the Sabi River in the central 
g 

~ 

~ cc 

0 

I 

r 

0) 

~ 

,,,,,,,, lq, 

~ ~ 

f~ f't4 ~1/Jf}IJ~ ~ 

~ §f wl ;ff, {!~_.,%_ , , .... ,,,, ~ (~ .·\: {, '*tt~ 

~ ~ " 

Ln. ~~·-\ ~~ J: , 111'"~ t ~ I~ ~ ~ - ~ ~ ~ ~ ... :!- :¥· ~ ''~~ ~J ~IQ/illnf'IIJ, J-:,.,,""'• --- ~ . 30 

if 17 ---

0900 

15 

1351.7 \ ~~~ 1 31 - 8oo 1 --:o / 85o \ _;22 .......,1-«o ) 1Zf · 0 y 

o, : / \ 0 _2_9_ 'j''./ _, 16 0 ~ 28 -- 1 1352.1 180 \ ~ 1000 

1300 --- f ......., I 12()() \ • ' ·· I 26 ', ~· ~I \ 1349.1.: 1000/ 

( 

......... ~ '\1700 .......... __ 1__ 9 20 

... -:-- ~ 1352.3 \ : --2-

5- t a ·~,. __ 1000 ----rfO()" '-

1 ... 3JE~.2.._ ... .---.. - ~ ... __ o_···---....A.. 2~~13oo ~4 

5 0 1369.4 __ 1_0_ 

........... ~ . 1359.7 ........_ ~Sabi exp~nment 

........... ~t1on M U S I K A V A N T H U -........_ ....._..._ IrE S E R V E 

................. 1-«oo ----------- · --,.3?s-- '-.... 09 -.... __ 

...... , 1379.7 -........_ ........... 

600 ' 

• 22 

~ 

1361.0 

z ....... 

Devuli Ranch 

.21 ~ 

1377.7 Chibuwe 500 

Humani Ranch 

35 

....U4 1316.4 

or ol2()() 

_3_3_ 

----rfO()" 

EXPLANATION 

Test • hole 

0 

Use~ ell 

Unuse'd well ()., 

Spring 

X 

1336 Altitude of water surface, 

in feet, Sabi River,Sept. 

1959 -1375- / ......... Contour on water table 

- .· ..;: ~ winter 1959 

/ ~ Contour in~rval, 25 feet 

. :::::.~ 22 

_, : '~ ~ 1361.0 

,,,,.;;-

':::-;~'-7,1111_- .: ,,:::,::~ - j: Upper number, ~ 

well num-

~,,,,~.:- her; middle number, 

/ 

g~1 111

~ , altitude of ground o 37 ~~~~~~~:'"' 11 ll:; water; lower number, 1321.8 --- u/l!fl specific conductance 

1200 ~ -

_3_8_ -~I{J11111111~ 1323.2 ~ 

-soD 0 /1'//!JIII'l, 

~ ~ 

1319 

25,000 --?42 

Zizu 

MUSIKAVANTHU 

RESERVE 40 ,....... ....... , 1319 

... :~J,ts~.11.,.rj"?-7 -t "--~-"J!>-··· Go'~~~- ,._c...~,- ~-·· <'v) - <:::>. 

1 0 1 2 3 MILES 

FIGURE 372.2.-Map of part of Sabi Valley showing ground-water data. 

~ ~ 

8 

'"d 

> '"d 

t"J 

~ 

(/2 

H 

z 

~ t"J 

0 

t"J 

0 

t"4 

0 

0 

8 

~ t:=' 

~ 

1-<1 

t:=' 

~ 

0 

t"4 

0 

G') 

·8 

fl5 

~ 

t"J 

~ t"J 

~[Jl 

> 

~ 

j 

~ t"J 

[J2 

t-:1 

~ 

~ 

I 

~ 

~ 

Q1 

t:1 

(J.!) 

~ 

(J.!) 
D-234 GEOLOGICAL SURVEY RESEARCH 19 61 

and southern parts of the area shown on figure 372:2 

before firm conclusions may be reached on the direction 

of ground-water movement in the area. 

RECOVERY OF GROUND WATER FROM WELLS 

The amount of ground water that might be obtained 

from wells in the river sand in the Sabi River channel 

could not be det.ermined in this study, but it is possible 

to make rough estimates based on tests in similar sand 

in the bed of the Umzingwani River in western Southern Rhodesia. The coefficient of transmissibility of the 

sand of the Umzingwani River for a saturated thickness of about 10 feet was about 180,000 gpd (gallons 

per day) per foot, and the storage coefficient was 0.33. 

The sand in the Sabi River channel may have coefficients in the same order of magnitude. Assuming this 

and using a water-table gradient of 1 foot per 1,000 

feet and a saturated thickness of 30 feet for a cro~s 

section of 3,960 feet, it is estimated that the Sabi River 

sand has an underflow of about 2,138,400 gpd, or about 

31h cfs, and the amount of water in storage in the 

Sabi River sand for each mile length of channel is about 

206,997,120 cubic feet, or about 4,500 acre feet. These 

figures refer to water in storage only and do not take 

into account recharge that would occur from the Sabi 

River. 

Although these are rough estimates based on inadequate data, they show that the river sand contains a 

large amount of recoverable water and that this method 

of calculation can be used when information from test 

drilling and pumping tests on the river $ands are 

available. 

Deeper sands are present not only beneath the river 

but throughout the valley, and these offer promise of 

supplying irrigation wells. Test holes drilled during 

the present investigation indicated good water-bearing 

sands to a depth of at least 340 feet at .the Sabi Experiment Station and to 191 and 296 feet in a section extending from the Sabi River to the escarpment east of 

Chibuwe. As none of these holes reached the base of 

the alluvium the total thickness of the water-bearing 

sands is unknown. 

QUALITY OF WATER 

The general chemical quality of the ·ground water 

from the wells and springs was determined .by 50 analyses. Samples taken from wells near the river are less 

mineralized than samples from wells near Ripisi Hot 

Springs, suggesting that infiltration from the river is 

taking place. Samples from wells along the eastern 

. scarp have only a moderate mineral content, indicating 

accretions of fresher water from the eastern highland 

mass. 

Water from test liole 39 is very highly mineralized. 

In the same area, test hole 40 was abandoned as too salty 

without a sample of water being taken for analysis. 

The reason for the highly mineralized water in the 

southern part of the area has not been determined. 

PALEONTOLOGY, GEOMORPHOLOGY, AND PLA!VT ECOLOGY 

373. GEOLOGIC RANGES OF CENOZOIC NONMARINE DIATOMS 

By KENNETH E. LoHMAN, Washington, D.C. 

The increasing need for making age determinations 

of a number of Tertiary nonmarine sediments that contain diatoms, frequently as the only available fossils, 

pointed up the necessity for determining the geologic 

ranges of the nonmarine diatoms with greater accuracy 

than previously known. One of the best methods of 

achieving this would be to collect diatomaceous sediments associated with well-authenticated vertebrate 

fossils. Accordingly, many vertebrate collecting localities in the Great Basin were visited and sampled for 

diatoms. Diatoms in adequate abundance were found 

in many of thes~ localities froni which the following 

were selected as having the best combination of tttbundant and well-preserved diatoms, well-dated vertebrate 

faun~s, and simple geologic structure, so that the stratigraphic relations of the diatomaceous beds and those 

carrying vertebrate fossils could be established 

unequivocally. 

1. Lower Virgin Valley beds, Humboldt County, Nev. 

Age determined as late middle Miocene on the basis 

of a definitive vertebrate fauna by Merriam (1910). 

2. Upper Virgin Valley beds, Humboldt County, Nev. 

Age determined as late Miocene on basis of vertebrate 

fauna by Merriam (1910). 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-43!) D-235 

3. Esmeralda formation as exposed on the east flank of 

Cedar Mountain, N ye County, Nev. Age determined 

as early Pliocene on the basis of definitive vertebrate 

faunas by Merriam ( 1916) and Stilton ( 1936, 1940). 

4. Thousand Creek beds, Humboldt County, Nev. Age 

determined as middle Pliocene on the basis of extensive vertebrate fauna by Merriam (1910). 

5·. I-Iagerman lake beds, near Hagerman, Idaho. Age . 

originally determined as late Pliocene on the basis of 

extensive vertebrate collections by Gidley ( 1930, 

1931), Gazin ( 1933-35), and Wilson ( 1933), but later 

changed by Gazin a~d others to early Pleistocene as 

the result of additional ver-tebrate collections and a 

reev::tluation of the earlier ones. The early Pleistocene age is also indicated by the nonmn.rine mollusks 

studied by Dwight W. Taylor (oral communication, 

1960) and is in better agreement with field mapping 

of these sediments by Howard A. Powers (oral communication, 1960). 

6. Provo formation in Goshen Valley, Utah County, 

Utah. Age determined as late Pleistocene (14,000 

years B.P.) on the basis of carbon-14 measurement 

by Meyer Rubin (oral communication, 1960) . 

Cpllections of diatoms from measured sections at 

these localities were made either from the vertebratebearing beds directly or from their stratigraphic equivalents a short distance .along the strike. At most 

localities, collections were also made from both below 

and above the vertebrate-ben,ring beds. Thus, the vertebrn,te collections were used as a primary standard with 

which to date the diatoms· in association with them. 

Over 400 species and varieties of nonmarine diatoms 

were identified from these collections, of which 85 were 

described as new. 

The results are summarized briefly on figure 373.1, 

where the width of the vertical columns is proportional 

to the number of species( indicated by the scale) found 

in each category. The six columns at the left indicate 

long-ranging species still represented in living assemblages elsewhere. Although in themselves not definitive for age determination, these long-ranging forms 

are very useful for paleoecologic.al interpretations. 

The shorter columns on the right show the distribution 

of short-ranging extinct species, which are most useful 

for age determination. 

As a result of this study, which is being augmented by 

the examination of additional well-dated collections, 

geologic .age determinations of strata by means of their 

contained diatoms can be made more accurately than 

before. 

REFERENCES 

Gazin, C. L., 1933, A new shrew from the upper Pliocene of 

Idaho: Jour. Mammalogy, v. 14, p. 142-144. 

--1933, New felids from the upper Pliocene of Idaho: Jour. 

~1ammalogy, v. 14, p. 251-256. 

--1934, Fossil hares from the late Pliocene of southern 

Idaho: U.S. Natl. Mus. Proc., v. 83, p. 11l·-121. 

--1934, Upper Pliocene mustelids from the Snake River 

Basin of Idaho: Jour. Mammalogy, v. 15, p. 137-149. 

--1935, Gravigrade sloth remains from the late Pliocene 

and Pleistocene of Idaho: Jour. Mammalogy, v. 16, p. 52-60. 

--1935, A new antilocaprid from the upper Pliocene of 

Idaho: Jour. Paleontology, v. 9, p. 390--393. 

Gidley, J. W., 1930, A new Pliocene horse from Idaho: Jour. 

Mammalogy, v. 11, p. 300-303. 

LonQ-ranginq species still represented 

in living assemblages 

LATE 

EARLY 

LATE 

PLIOCENE MIDDLE 

EARLY 

LATE 

MIOCENE MIDDLE 

EARLY 

Short-ranging extinct s·pecies 0 30 t t I I 

Species 

FIGURE 373.1.-Geologic ranges of Cenozoic nonmarine diatoms . • 
D-236 GEOLOGICAL SURVEY RESEARCH 19 61 

Gidley, J. W., 1931, Continuation of the fossile horse round-up 

on the Old Oregon T'rail: Smithsonian Inst. Explor. and 

Field Work in 1930, p. 33-40. 

Merriam, J. C., 1910, Tertiary mammal beds of Virgin Valley 

and Thousand Creek in northwestern Nevada: California 

Univ. Dept. Geol. Sci. Bull., v. 6, p. 21-53. 

--1916, Tertiary vertebrate fauna from the Cedar Mountain region of western Nevada: California Univ. Dept. 

Geol. Sci. Bull., v. 9, p. 161-198. 

Stirton, R. A., 1936, Succession of North American continental 

Pliocene mammalian faunas: Am. Jour. Sci., 5th ser., v. 32, 

p. 161-206. 

--1940, The Nevada Miocene and Pliocene mammalian 

faunas as faunal units: Pacific Sci. Assoc., 6th Pacific Sci. 

Cong. Proc., v. 2, p. 627-640. 

'Vilson, R. ·w., 1933, A rodent fauna from later Cenozoic beds 

of southwestern Idaho: Carnegie Inst. 'Vashington Pub. 

no. 440, p. 117-135. 

374. EARLY CRETACEOUS (MIDDLE NEOCOMIAN) MICROFOSSILS IN SOUTH-CENTRAL ALASKA 

By HARLAN R. BERGQmsT, Washington, D.C. 

A small microfauna of middle N eocomian age has 

been found in rocks associated with the N elchina limestone in the Talkeetna Mountains, south -central Alaska. 

This is the second record of Fora1ninifera of middle 

N eocomian age in North America-one foraminifer has 

been described from rocks of Hauterivian age near Coa.-

huila., Mexico (Loeblich and Tappan, 1952). 

The microfossils were found in a few samples that 

were collected by Arthur Grantz and Leo Fay from silty 

shale beds within and below the N elchina limestone at 

five localities along Tyone Creek and along tributaries 

to Bubb and Billy Creeks (fig. 374.1). The microfauna consists largely of calcareous Foraminifera and 

a few species of Radiolaria, and in addition 2 species of 

ostracodes were found in 2 samples. The Foraminifera 

consist of 17 species of lagenids, 1 rotalid species; and 

FIGURE 374.1.-Loca•tion of Lower Cretaceous microfossil collections from Nelchina limesitone (Neocomian age), south-central 

Alaska. 

1 agglutinate species. Some of the F.oraminifera appear to be the same as species des~ribed from rocks of 

middle Neocomian (Hauterivian) age of Glanerbrug, 

Netherlai1ds (ten Dam, 1946, 1948). 

Three of the samples were collected frmn an area 

south of the Little N elchina River. Collection 

52AGz174A (fig. 374.1) came from silty partings in 

massive N elchina limestone on a north tributary of 

Bubb Creek, 3.38 miles S. 21 °30' E. of the main headwater fork of the Little N elchina River. The N elchina 

limestone there overlies a sandstone unit containing 

Buchia crassicollis (l(eyserling) of middle Valanginian 

age as identified by Ralph Imlay (Grantz, 1953). The 

sample yielded 6 species of Foraminifera, including 2 

that are common to abundant. Two collections 

( 53AGz190 and 53AGz201) were made at Limestone 

Gulch, a tributary of Billy Creek, about 23,4 miles 

southwest of the locality on Bubb Creek. Collection 

53AGz190 from a siltstone unit immediately below the 

Nelchina limestone contained 14 species of Foraminifera; 4 were common to abundant. Collection 

53AGz201, from a silty parting within the Nelchina 

limestone, yielded 15 species of Foraminifera, the most 

found in any of the sample~. Six of the species are 

common to abundant. 

Other collections ( 54AGz101, 102, 103, and 54AFy57 

and 71) were 1nade frmn rocks associated with the 

N elchina limestone along tributaries of Tyone Creek, 

north of the Little Nelchina River (fig. 374.1). Foraminifera from these are similar to. those in the other 

collections, but the samples yielded fewer species; only 

2 species were common to abundant in 2 of the collections. Three of the collections ( 54AGz102 and 103, 

and 54AFy71) had abundant specimens of Radiolaria. 

Because only a few microfossil samples have been 

obtained from these Early Cretaceous rocks associated 
SHORT PAPERS IN THE GEOLOGI<C AND HYDROLOGIC BqiENCES, ARTICLES 2 9 3-4 3 5 D-237 

with t.he N elchina limestone, and additional samples 

could not be collected readily, only tentative identifications ha.ve been made of the fossils as shown in table 

TABLE 374.1.-Distribution of microfossils in samples from Early 

Cretaceous (Neocomian) strata, south-central Alaska 

(Number or specimens oro given If less then 12 were found; C, common (12 to 25 

specimens); A, abundant <25 to 50 specimens); V, very abundant (more than 50 

spoclmons found); r, fragment] 

Collection number 

Fossil -< ..... ~ ~ ~ ~ s ~ ~ 0 0 "' ·o 0 "' 0 0 ~ 

-< -< -< -< -< -< -< ~ ~ ~ ;:!.; ;:!.; ;:!.; ;:!.; 

------------

Marssonella oxycona (Reuss)_ A A A 7 A c A 

Lenticulina munsteri (Roe- mer) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 8 A V A C C 

sp. (multichambered)__ C C C 5 ---- ---- ----

Robulus sp. A (raised su- tures) __________________ 2 2 4 6 ---- 10 

sp. B (smooth wall)____ _ _ _ _ _ _ _ _ C ____ ---- -- __ - _--

Marginulina cf. M. robusta 

Reuss __________________ --- _ 7 C 1 ---- ---- sp ___________________ --- _ 2 - _-- __ -- ---- -- _- ----

Marginulinopsis cf. M. 

gracillissima (Reuss) _____ ---- 1 1 ____ ---- ---- ----

Nodosaria sp. A (5 costae)_- --- _ 2 - _-- ---- 3 -- _- ----

sp. B (7 costae) _______ ----____ 4 ----------------

Dentalina aff. D. gracilis 

d'Orbigny ______________ ---- ---- 2 ----------------

Rectoglandulina sp _ _ _ _ _ _ _ _ _ 1 ____ - __ - ___ - --- _ - - __ - __ -

Saracenaria BP------------- ---- 6 2 ---- ---- ---- ----

Vaginulina SP------------- ---- 2 1 ---- ---- ---- ----

V aginulinopsis cf. V. pachynota ten Dam___________ 3 7 3 ---- ---- --- _ 1 

reticulosa ten Dam _____ --- _ 1 10 1 ---- 1 

SP------------------- -------- 8 ----------------

Frondicularia sp. (costate)_- ---- f ---- ---- ---- ---- ----

Epistomina caracolla 

(Roemer) _______________ ---- C C ---- ---- ---- ----

Radiolaria: 

N asselina_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ P A A A 

Spumellina ____________ ---- ____ ---- ____ A P A 

Ostracoda: 

sp. A, smooth carapace_ --- _ 

sp. B, ornamented carapace __ - - - - - - - - - - - - - - - - -

p ---- ---- ---- ---- p 

p ---- ---- ---- ---- ----

374.1. Of the Foraminifera, the following were common or abundant in one or more samples: 11! arssonella 

owycona (Reuss), Lenticulinc~ cf. L. m!Unsteri (Roemer), Lenticulina §'p., Robulu..(( sp. B, M arginulina cf. 

11!. robusta Reuss, and Epist01nina caraoolla (Rbemer). 

Some of these are the same species that have been found 

in rocks of middle Neocomian age in Germany, England, and near Glanerbrug, Netherlands. Two species, 

Y aginuiinopsis cf. Tl. paohynota ten Dam and Y aginulinop8is reticulosa ten Dam, though of relatively 

rare occurrence, appear to be the same as forms described from middle Neocomian rocks in the Glanerbrug, Netherlands area (ten Dam, 1946). 

Radiolaria in these samples are nasselline and spumelline forms belonging to the Stichocorythidae, Triacartidae, and Liosphaeridae. Specimens are large, and 

most have been somewhat distorted by compression. 

Stichocorythidian forms which may be species of Dictyomitra.fi and Oyrtocapsa? are most abundant. Spumelline forms are represented only by Liosphaeridae, 

which seem to be entirely cenosphaerids and cenOdiscids. 

The Radiolaria in collection 54AGz102 are cenosphaerids and stichocorythidian forms and are preserved as 

incomplete glauconitic casts. Collection 53AGz201 has 

a few glauconitic casts of stichocorythidian forms. 

Strata of N eocomian age in south-central Alaska 

have not been extensively sampled for microfossils; it 

is intended here only to call attention to thel.r presence 

in these rocks. The Foraminifera are of particular 

interest as little is known about this group of organisms 

in the earliest Cretaceous rocks of North America. 

REFERENCES 

Grantz, Arthur, 1953, Preliminary report on the geology of the 

Nelchina area, Alaska: U.S. Geol. Survey open-file report. 

Loeblich, A. R., Jr., and Tappan, Helen, 1952, The Foraminiferal genus Tri,plasia Reuss, 1854: Smithsonian Misc. Coll., 

v. 117, no. 15, p. ·15, pl. 2, figs. 21, 22. 

ten Dam, Abraham, 1946, Arenaceous Foraminifera and Lagenidae from the Neocomian (Lower Cretaceous) of the 

Netherlands: Jour. Paleontology, v. 20, no. 6, p. 570-577. 

-- 1948, Foraminifera from the middle N eocomian of the 

Netherlands: Jour. Paleontology, v. 22, no. 2, p. 175-192. 
D-238 GEOLOGICAL SURVEY RESEARCH 1 9 61 

375. LATE PERMIAN AMMONOIDS IN THE INYO RANGE, CALIFORNIA, AND THEIR SIGNIFICANCE 

By MACKENZIE GoRDoN, JR., and CHARLES W. MERRIAM, Washington, D.C. 

'Three collections from the upper part of the Owens 

Valley ·for:mation in the Inyo Range contain Late 

Permian ammonoids associated with "Pwnctospirifer" 

pulcher (Meek) and Neospirifer · pseudocaiJ'fWratus 

( Girty). The material was collected by M. W. Ellis 

during the mapping of the New York Butte quadrangle 

by W. C. Smith and C. W. Merriam. All three of the 

localities are high on the west slope of the range and 

within an area less than a mile square, 5 to 6 miles 

north west of Cerro Gordo. They are reached from 

Swansea by the old Salt Company road, now a jeep 

trail, and lie within half. a mile southeast of the 

abandoned salt tramway. 

The rock matrix of these collections is a partly 

metamorphosed siliceous limestone, somewhat conglomeratic, containing small granules and pebbles, mostly 

of chert. The fossils are silicified, generally distorted 

or fragmental, and poorly preserved for the most part, 

but the principal elements of the sutures of the ammonoides can be distinguished. Stacheocerfl8 occurs in all 

three collections and X enfl8pis and Timorites in one o£ 

them. The fossils are listed in the table below. 

Species 

Late Paleozoic 

.Collection No. 

17706 17710 17711 

----------------1----------

Triticites or Schwagerina sp _ _ _ _ _ _ _ _ _ _ _ _ _ X ___________ _ 

Schwagerina or Parafusulina sp__________ X ___________ _ 

Fenestrate bryozoan, genus indet_ _ _ _ _ _ _ _ X X 

Leioclema? sp_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ X 

Schuchertella? SP-----------~----------- X -~---- _____ _ Productid brachiopod ______________________ ·_ _ _ _ _ _ _ _ X 

Cancrinella cf. C. phosphatica (Girty) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ X 

Dielasmid brachiopod__ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ X 

Rhynchopora taylori Girty _ _ _ _ _ _ _ _ _ _ _ _ _ _ X X X 

Wellerella cf. W. rotunda Cooper_______________ X X 

Welleralla? cf. W. hemiplicata Cooper____ X ___________ _ 

"Punctospirifer" pulcher (Meek)_________ X X X 

N eospir~f er pseudocameratus ( Girty) _ _ _ _ _ _ _ _ _ _ _ _ X X 

Crinoid columnals _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ X X 

Schizodus sp _________________________ - X ____ -- ------

Bellerophontid gastropods _____________ - ·X X X 

Omphalotrochid gastropod ______________ ----~------- X 

Mooreoceras? sp_·---------------·--·----- X ___________ _ 

Stearoceras aff. S. phosphoriense (Branson)_ _ _ _ _ _ _ _ _ _ _ _ _ X 

Xenaspis aff. X. carbonarius (Waagen) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ X 

Stacheoceras aff. S. antiquum (Waagen)___ ? ?. X 

Timoritescf. T.uddeniMillerandFurnish _____________ X 

Ammonoid indet ___________ "" _________ - X - ___ -- ------

Fish_________________________________ X X 

The fusulinids, which were identified by R. C. Douglass,\ are reworked Early Permian types. The amm.onoids are mostly fragmental and certainly dirl not 

live precisely where they are now found. The more 

common brachiopods, however, because of their relative 

abundance and entirety, appear to be now buried approximately where they lived. Merriam and Hall 

( 1957, p. 11) have recognized three paleontologic zones 

in the Owens Valley formation, in descending order as 

follows: 

3. N eospirifer pseudocameratus zone 

2. Parafusulina zone 

1. Pseudoschrwagerina zone 

The present assemblage belongs In the uppermost of 

these zones. 

The brachiopods are representatives of the ubiquitous 

"Punctospirifer" pulcher fauna which occurs also in 

the the Retort phosphatic shale and Tosi chert members 

of the Phosphoria formation in southeastern Idaho, 

and the Franson and Ervay carbonate rock members of 

the Park City formation in northeastern Utah, as well 

as the Gerster formation of western Utah and eastern 

Nevada (Williams, 1959). These beds generally have 

been considered in the past to· correlate with the Word 

formation of west Texas. · 

The ammonoids Xenaspis and Timorites, however, 

are gener~ that first appear in Late Permian time and 

are characteristic of the Timorites zone (Miller and 

Furnish, 1940, p. 29) that is best known from the 

Capitan limestone of west Texas and Coahuila, Mexico, 

and from the Amarassi beds of Timor. The Stacheoceras is an advanced form probably of rather late 

Permian age. 

The occurrence of these Upper Permian ammonoids 

in the Inyo Range is of significance in dating the upper 

part of the Owens Valley formation. Their association with the "Punctospirifer" pulcher fauna suggests 

that these brachiopods may have a higher stratigraphic 

range than heretofore established. But the specter of 

reworking of at least some of the fossils cautions 

against drawing too firm conclusions without further 

study. 

REFERENCES 

Merriam, C. W., and Hall, W. E., 1957, Pennsylvanian and 

Permian rocks of the southern Inyo Mountains, California: 

U.S. Geol. Survey Bull. 1061-A, 13 p. 
SHORT PAPERS IN THE GEOLOGI·C AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-239 

Miller, A. K., nnd ]j"'urnish, W. M., 1940, Permian ammonoids 

of the Gundeloupe Mountnin region and adjacent areas : 

Geol. Soc. America Spec. Pnper no. 26, 242 p. 

'Villinms, J. S., 195.9, Fnunn, age, nnd correlation of rocks 

of Parl\: City age, in McKelvey, V. E., and others, The 

~hosphoria, Pnrk City, and Shedhorn formations in the 

western phosphate field: U.S. Geol. Survey Prof. Pnper 

313-A, p. 36-41. 

376. A STRATIGRAPHICALLY SIGNIFICANT ASSOCIATION OF SMALLER FORAMINIFERA FROM WESTERN 

FLORIDA 

By S. M. HERRICK, Atlanta, Ga. 

The Foraminifer 11/ a·rginulina vacavillen8is (Hanna) 

has been found in subsurface strata of Lisbon age in 

western Florid~t. This fossil, originally described from 

the United States west coast (Hanna, 1923, p. 324), was 

observed in wells where it occurs with Robulus inornatus ( d'Orbigny) and Robulus alato-limbatus (Gumbel), 

and, n.t several localities, with Robulus 7Jseudovortex 

Cole. T'hese localities are in Santa Rosa, Escambia, 

and Okaloosa Counties. 

Fisk ( 1940, p. 133, pls. 3-5) reported If en?Jicristellaria ( ? ) nudicostata 1 [="AI arginulina vacaville118is] as 

a. guide fossil for the Cane River formation in Louisinna. The writer has noted 11/ a'rginulina vacavillensis 

together with Robulu8 ino'rnatus n.nd Robu7Ju8 alatolirnbatv-8 in the middle part of the Cane River formation from two wells in Natchitoches Parish, La. Likewise these three species, and at some places a fourth 

species, Robulus pseudovortex, have been used by the 

writer as subsurface guide fossils for the Winona sand 

in areas throughout the major part of the Tertiary sediments in Mississippi. The finding of these four fossils 

in western Florida constitutes another occurrence of 

this association in the United States Gulf Coast. Such 

an association should prove useful in identifying and 

correlating strata of late middle Eocene age in the 

Southenst. 

REFERENCES 

l!'isk, H. N., 1940, Geology of Avoyelles and Rapides Parishes 

[La.] : Louisiana Dept. Conserv., Geol. Survey Bull. 18, 

240p. 

Hanna, G. D., 1923, Some Eocene Foraminifera near Vacaville, 

California: California Univ. Dept. Geol. Sci. Bull., v. 14, 

no. 9, p. 319--328. 
D-240 GEOLOGICAL SURVEiY RESEARCH 19 6 1 

377. DISCHARGE OF GROUND WATER BY PHREATOPHYTES IN THE WAIANAE DISTRICT, OAHU, HAWAII 

By C. P. ZoNEs, Honolulu, Haw~ii 

Work done in cooperation with the State of Hawaii 

The 'Vaianae district in western Oahu, Hawaii, is 

bounded on the west by the sea and on the north, east, 

and south by the crest of the 'Vaiariae Range, whose 

maximum altitude is a little more than 4,000 feet. 

'Vestward-trending spurs of the mountain range divide 

the area into five large valleys and several smaller 

ones (fig. 377.1). Rocks comprising the mountain 

range are mainly lava flows ; terrestrial and manne 

sedimentary rocks of unknown thickness underlie the 

valleys. The semiarid coastal areas receive less than 

20 inches of rain a year, whereas the ]ntmid mountainous areas receive 70 to 100 inches a year. 

Potable ground water occurs principally in a GhybenHerzberg lens, which floats on sea water in the underlying saturated rocks that occur below sea level, and 

also in compartments partly or entirely bounded by 

relatively impermeable dikes in the volcanic rocks 

(fig. 377.2). The water level within the dike compartments is higher than in the Ghyben-Herzberg lens and 

may be higher or lower than the water level in adjoining compartments. Ground water within the compartments moves slowly into adjoining compartments or 

down into the Ghyben-Herzberg lens. Discharge from 

the compartments also takes place by spring flow, by 

discharge into streams, probably by evapotranspiration, 

and by artifical withdrawal. 

Ground water in the Ghyben-Herzberg lens moves 

seaward at a gradient that ranges from less than 2 feet 

to about 10 feet per mile. An unknown quantity of 

ground water discharges into the sea by diffusion or 

mixing in the transition zone between fresh water and 

sea water and perhaps also by discharging directly into 

the sea. A small part of the water is discharged from 

wells and a part discharges into lower reaches of stream 

channels, but discharge of ground water by these means 

accounts for only a small fraction of the estimated total 

annual recharge. 

Water-level records in two wells indicate that a substantial quantity of ground water in the 'Vaianae 

district returns to the atmosphere by evapotranspiration. These records show a daily rise and fall of the 

water table that is typical of areas where evapotranspiration takes place from the water table or from the 

capillary fringe above it. The records were obtained 

from Oahu dug well 1 and from test well T-76 (fig. 

377.1). Evaporation from the capillary fringe occurs 

at a few places, but the areas are too small to account 

for the daily rise and fall of the ground-water level.. It 

is apparent that discharge of ground water must be 

effected by phreatophytes. 

The dominant types of vegetation in the immediate 

areas of the two wells are koa haole ( Le'lwaena gla'lwa) 

and algaroba, or kia we ( Prosopis chilensis). Koa haole 

becomes dormant and dries out during periods of little 

or no rain, but turns green for several days after a heavy 

rain. Algaroba, which is a close relative of the mesquite 

common to the arid southwestern parts of the conterminous United States, appears to be unaffected by prolonged dry periods, except at altitudes of several hundred feet above sea level. As there are no other plants 

growing in sufficient profusion. in the area to affect 

water levels appreciably, it is concluded that algaroba 

is the plant principally responsible for the daily 

fluctuation of the water table. 

In the 'V aianae district, the heaviest growth of 

algaroba is on the coastal lowlands, where the water 

table is less than 10 or 15 feet below the land surface. 

There, algaroba grows to heights of 35 to 40 feet and 

has an areal density of 80 to 100 percent. At increasingly higher altitudes, the algaroba becomes smaller 

and koa haole becomes dominant. At the highest altitudes at which algaroba grows it is stunted and has an 

areal density of not more than . about 20 percent. Its 

distribution, density, and height are shown on figure 

377.1. The upper limit of its growth, except for isolated 

trees or small groups of trees, is at about 400 feet above 

sea level in Makaha, 'Vaianae, Lualualei, and N anakuli 

Valleys, and about 200 feet above sea level elsewhere in 

the Waianae district. At the higher altitudes the depth 

to the permanent ground-water body may be nearly 400 

feet, except where these areas are underla1n by ground 

water in dike Qompartments. The latter condition· 

occurs in upper 'Vaianae Valley, where the depth to 

water in the areas of algaroba growth is generally less 

than 200 feet. The condition may exist also in other 

areas. · It is not known to what depth the roots of 

algaroba can penetrate. Possibly much of the a.lgaroba 

growing at higher altitudes subsists on soil moisture 

or on small perched ground-water bodies that are 

depleted during periods of drought. This may account 

for the observed wilting of the algaroba at the higher 

altitudes during dry periods. 

Algnroba apparently has a high salt tolerance, for 
0 

SHORT PAPERS IN THE GEOLOGI·C AND HYDROLOGIC SCIENCES, ARTICLES 293-435 

EXPLANATION 

lllllllll~llllllllll Algaroba 

Uppe·1· ·n:1unbe·1', n·renl density of ftlgn·roba, in 

pe·1·cent; lower number, ave·mge height of 

nlga:robft, in feet. ( Mftpped in May, 1960) 

N 

2 3 4 MILES 

158"00' 

' '\ 

' 

~-.') 

-----

_ / ___....... 

' 

~ ' "' I 

I \ 

"' I 

) 

/ 

I 

' \ 

I 

I I 

) 

D-241 

l!"'murtE 377.1.-lVlup of the "'uiunae district, Oahu, Hawaii, showing geographic features of the area and the distribution 

of algaroba. 
D-242 GEOLOGICAL SURVEY RESEARCH 1 9 61 

High-level ground water in dike compartments 

Area of ground-water discharge by phreatophytes 

FIGURE 377.2.-Diagrammatic section. illustrating the occurrence of ground water in the Waianae district, Oahu, Hawaii. 

Wide black lines represent relatively impermeable dikes. 

it grows luxuriantly where the ground water contains 

more than 1,000 ppm (parts per million) chloride, and 

there is a dense stand of algaroba even in the vicinity 

of well T-76, where the water at the top of the lens contains more than 5,000 ppm chloride. 

The amount of ground water used by algaroba In 

Hawaii has not been determined. However, a preliminary estimate of ground-water recharge in the Waianae 

district as compared to known and estimated quantities 

discharged by means other than transpiration by phreatophytes indicates that discharge of ground water by 

algaroba is a major factor in the water budget. 

378. DEFLATION IN BUENA VISTA VALLEY, PERSHING COUNTl, NEVADA 

By RoBERT E. WALLACE, Menlo Park, Calif. · 

Work done in cooperation with the Nevada Bureau of Mines 

Buena Vista Valley is in central Pershing County, 

Nevada. Its lowest part, altitude approximately 4,035 

feet, is 25 miles east of Lovelock, Nevada, and 57 mileS 

southwest of Winnemucca. The area of the entire 

valley is about 400 square miles, and that of the nearly 

flat central valley floor is about 50 square miles. 

Buena Vista Valley is ·one of the numerous basins 

in Nevada having no external drainage, and represents 

a graben between two horst mountains, the Humboldt 

and East Ranges. Unconsolidated sediments have accumulated in this graben, and gravity measurements 

by Don R. Mabey (oral communication) indicate that 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-243 

these sediments are at least 8,000 feet thick. Most of this 

ma~erial probably accumulated during Pliocene and 

Pleistocene time. 

Lake sediments of Pleistocene Lake Lahontan are the 

youngest major deposits in the basin. The lake, which 

stood at about 4,370 feet (R. B. Morrison, written communication, 1958) in mid-Wisconsin time, dried up completely d:uring the warm, arid Altithermal age (of Antevs), some 7,000 to ±,000 years ago; and subsequently 

during the some"· hat moist Medithermal age (of Antevs) there were only very shallo"·, comparatively temporary lak~ (R. B. Morrison, ''ritten communication, 

1961). In modern times the basin has been dry except 

after tmusually heavy rain, when the lowest part of the 

basin is cov~red by a sheet of "·ater, a few inches to a 

few feet deep. 

This setting might suggest continuing accumulation 

of playa deposits in Buena Vista Valley, but such is not 

the case. The total balance appears to be one in which 

degradation outstrips aggradation, and the present relatively fiat floor of the valley is not primarily a surface 

of playa deposition, but rather a surface formed by deflation down to a resistant clay bed of late Lake Lahontan age. 

Especially good evidence for this interpretation can 

be seen in a gullied area along the southern margin of 

the central valley floor near lat 40°07.5' N. and long 

118°03' W. where the upper sediments of Lake Lahontan are well exposed in sections (see figs. 378.1 and 

N s 

FEE·, p 

~jL_·· -~_. __ _i_·· ·· ------ --·_(13>_: .· _.-:_· ----~-~:·_: .. _: ~' :~_:;_,·~-~-:~-~-~-:~-~-,~~; 0 500 FEET 

FIGURE 378.1.-Diagrammatic section across margin of central 

valley floor of Buena Vista Yalley. ShOFS deposits dissected 

down to deflation-resistant clay heel (C) ; salt-expanded laye1· 

(X) over clay bed; and locality (P) of photograph (fig. 

378.2). Scales are approximate. 

378.2). Here a distinctive bed of tough greenish 

highly saline clay is exposed, overlain by 10 to 15 feet 

of other sediments that are less resistant. The latter 

are lacustrine, alluvial, and eolian silts and sands, 

mostly thin bedded and lenticular, that are progressively more eroded toward the. playa, so that over the 

central valley floor the resistant clay bed is either at or 

within 10 inches of the surface . 

• \. long low ridge, trending northeast, is situated 

along a m~dial line of the valley bottom. This ridge 

FIGURE 378.2.-Photograph showing exposure of deflationresistant clay bed (between about waist and shoulder height 

of man). This exposure is in a gulch near the southern 

margin of the central valley floor of Buena Vista Valley. 

:\Tote the thickness of deposits overlying the clay bed, which 

have been deflated from most of the central valley floor. 

is about 10 feet high, one-half to one mile wide, and 

:;everal miles long. The lacustrine deposits within this 

ridge are interpreted as sediments stratigraphically 

higher than the resistant clay bed, and the ridge thus 

also represents a remnant not yet eroded from the 

valley bottom. 

The green clay bed has great water-retention power; 

it was moist within 2 inches of the surface in the area 

of figure 378.2, even in late August of a very dry year 

several months after a rain. The clay has the general 

consistency of modeling clay, and consequently, effectively resists wind erosion. 

In almost every area bordering the central valley 

floor, down-cutting by either stream erosion or deflation 

seems to dominate. Material eroded by streams from 

the marginal areas, of course, must be deposited in the 

valley bottom, but little material of this sort can be 

found there. On aerial photographs taken in 1952, 

large amoeboid-shaped patches, which represent deposition by individual floods, can be seen on the central valley floor. In 1957 some of these deposits were examined 

and found to be made up of clay- and silt-size material 

in a thin layer generally less than a quarter inch thick. 

In 1960 the author flew over the valley, and found that 

these same amoeboid-shaped patches had become very 

obscure, but other patches from more recent rains could 

be identified. 

Since Lake Lahontan time, alluvial sand and gravel 

from the highland washes have been deposited largely 

in the middle and upper parts of the old pre-Lake 

Lahontan fans, but the younger alluvium constitutes 

only a fraction of one percent of the total volume of 
D-244 GEOLOGI-CAL SURVEY RESEARCH 1 9 6 1 

the fans. Alluvial deposition of sand and gravel on 

the central valley floor is negligible. 

Material that is deposited over the resistant green 

clay is wetted during the rainy months of the year, and 

salt from underlying deposits becomes dispersed 

throughout. During the dry months the material dries 

out, and salt crystals grow and expand the material 

into a loose "sand" made up of salt crystals, silt, and 

cl~ty-size particles. Most of the surface of the central 

valley floor is underlain by 6 to 12 inches of such saltexpanded silt and clay. In many places a hard crust 

of salt develops over the loose "sand", but where the 

crust does not develop, the salt-expanded silt and clay 

are loose and very susceptible to wind erosion. 

On almost any summer day there is scarcely a moment 

when whirlwinds or "dust devils" ·can not be seen to be 

actively eroding the playa, and very frequently enormous dust clouds can be seen rising from it and being 

blown eastward. . 

In summary, although Buena Vista Valley contains 

more than 8,000 feet of late Cenozoic sediments, now 

more material is being carried away than is accuinulating. Deflation appears to be the dominant proce'ss in 

the erosion. 

379. OSTRACODES AND CONODONTS FROM THE GETAWAY LIMESTONE MEMBER OF THE CHERRY CANYON 

FORMATION (PERMIAN), TEXAS 

By I. G. SoHN, Washington, D.C. 

A limestone sample (USGS loc. 12856-PC), from 

Culbertson County, Tex., \vas digested with acetic acid 

and yielded abundant silicified I()Stracodes and some 

conodonts. Associated forms. include fragments of 

larger fossils, sponge spicules, fusuline Foraminifera, 

biserial and coiled smaller Foraminifera, Bryozoa, fish 

teeth, and one fragment of a trilobite. These are the 

youngest Permian ostracodes and conodonts known to 

date in the United States. A second collection (USN~f 

loc. 712) from the same general locality, when treated 

with .hydrochloric acid by G. A. Cooper; yielded the 

same ostracode faunule, but no conodonts. 

Previous to these finds, the youngest Permian ostracodes that had been described (Hamilton, 1942; Sohn, 

1950, 1954) were reported from the uppermost limestone of Leonard age or lowermost limestone of.vVord 

age of the Glass Mountains, Tex. (USNM loc. 703c). 

Conodonts were not recovered from this locality, probably because hydrochloric acid was used. 

A preliminary list of ostracodes from Getaway limestone member is given below. 

.Aoratia sp. 

.Alvenus? sp. 

Amphissites n. sp. aff.. .A. centronot1ts (Ulrich and BasOeratobairdia spp. 

Ooryellina? sp. 

Oryptobai1·dia sp. 

Glyptoplettra spp. 

sler), 1906 Healdia vidriensis?, Hamilton, 

.AurUdrkbya n. sp. aff. A. 1942 

B;:;::::;. (Hamilton)' 11)42 Healdia sp. 

B airdiacypris sp. K indlella? sp. 

Oavellina sp. Miltonella shupei Sohn, 1950 

Oemtoba,·inUa wonlensus 

(Hamilton), 1942 

Pa,ra,parchites marathonensis 

Hamilton, 1942 

Polytylites digitahts? Sohn, Sa/nsabella? sp. 

1954 Gen. indet. Kirkbyidae 

Romulyella dorsopapillosa '! Gen. indet. frilled 

Sohn, 1954 Gen. indet. smooth. 

These ostracodes resemble the. faunule described from 

the Glass Mountains. I have observed poorly preserved 

specimens of Oeratobairdia in shale collected from· the 

Middle Productus limestone in the Salt Range, 

Pakistan. 

The conodonts in the Texas collections are small, 

mostly broken but not worn, amber colored, translucent 

genera of the fmnilies Priniodonidae, Idiognathodontidae, and Polygnathidae (Hass, 1958). Gondolella is 

present in the ·collection and is also reported from the 

Phosphoria, formation in Idaho (Youngquist, Hawley, 

and Miller, 1951, p. 360). 

The localities and the collectors are as follows: 

USGS 12856-PC. Approximately middle of Getaway member of 

Cherry Canyon· formation, limestone with silicified fossils. 

Road to Guadalupe Summit beacon, from cliff below flat 

place in road, just before it climbs to beacon; Culbertson 

County, Tex., collected by I. G. Sohn, G. 0. Bachman, and 

D. A. Myers, l\'Iay 21, 1960 . 

USNM 728. Getaway member, Cherry Canyon formation, on the 

west side of ainvay station. road, between the road and 

the crest of ridge, about 2% miles by road SS'V of Pine 

Spring Camp; Culbertson County, Tex., collected by G . 

A. Cooper, July 15, 1952. Same locality as Am. Mus. 

~atural History no. 512. 

REFERENCES 

Hamilton, I. B., 1942, Ostracoda from the upper Permian of 

Texas: Jour. Paleontology, v. 16, p. 712-718. 
SHORT PAPERS IN THE GEOLOG~C ~D HYDROLOGIC SCIENCES, ARTICLES 293-435 D-245 

Buss, W. H., 1958, Classification and stratigraphic range of disjunct conodonts: "'ashingtou Acad. Sci. Jour., v. 48, no. 4, 

l'· 141-142. 

Sohn, I. G., 1950, Growth series of ostracodes from the Permian 

of 1'exns: U.S. Geol. Surve~· Prof. Paper 221-C, p. 33-39. 

--- 1954, Ostrucoda from the Permian of the Glass Mountains, Texas: U.S. Geol. ·survey Prof. Paper 264-A, 24 p. 

Youngquist, ·walter, Hawley, R. ,V., and Miller, A. K., 1961, 

Phosphoria conodonts from southeastern Idaho: Jour. 

Paleontology, v. 25, p. 356-364. 

380. PHYSICAL CHARACTERISTICS OF UPPER CAMBRIAN STROMATOLITES IN WESTERN UTAH 

By RICHARD K. HosE, Menlo Park, Calif. 

Geologic mapping in Tule Valley, Utah, has disclosed 

ab.undant carbonate stromatolites in the Notch Peak 

limestone of Late Cambrian age (fig. 380.1). Reconnaissa,nce in the southern House Range, which is adjacent to Tule Valley on the ea,st, has provided additional 

data as to mode of occurrence and stratigraphic position 

of the stromatolites and has disclosed a few occurrences 

in the Johns '\V ash limestone and the Orr formation 

both of Late Cambrian age. 

The present p~iper records the occurrence of the 

stromatolites and briefly describes those of the upper 

500 feet or so of the Notch Peak limestone. It is hoped 

that recognition of similar forms elsewhere will facilitate correlation, genetic interpretations, and paleoecology of Upper Cambrian units of the eastern Great 

Basin. 

Figure 380.2 shows the generalized stratigraphic section of U ppe_r Cambrian formations exposed in Tule 

Valley nnd the House Range. The nomenclature is 

modified from Bentley (1958) and Drewes and Palmer 

(1957). 

Stromatolites of the Notch Peak formation are 

typically cylindrical to slightly conical masses with 

axes perpendicular to bedding. The stromatolites 

range ft·om 2 to 4 feet in height (fig. 380.3) and from 

6 to 1.8 inches in diameter (fig. 380.4). ~iost of them 

are circular in plan, but some are irregular and 

poly lobate. Sections cut pa.ralJel to the long axis reveal 

that the laminations are convex upward; the curvature 

is slight near the base but increases upward and beeomes parabolic (fig. 380.3) in the upper part. In 

plan view the· laminations are concentric (fig. 380.4). 

The bn,sal pa.rts of most adjacent stromatolites are in 

eontact but, because of their slight upward taper, the 

upper parts are not. The spaces between adjacent 

stromatolites are filled mostly with coarse-grained 

detritnJlimestone but locnJly the filling is homogeneous 

dense limestone. Generally the detrital limestone 

filling is lighter colored than the stromatolites. 

113'30' 113'15' 

~Utah Lake 

~ • Delta 

~Sevier Lake 

0 5 MILES 

1!-,IGURE 38.0.1.-Index map of west-eentral Utah showing 

stromatolite localities ( X ) discussed in text. 
D-246 GEOLOGICAL SURVEY RESEARCH 1961 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

I 

II 

I 

I 

IT 

I 

I 

I 

I 

I 

I I I I 

I 1 I I 

I I I I 1 

I T I I 

I l I 

1 -1 I I 

I I I 

I I I I 

I I I 

I I I 

I I I I 

H ouse limestone 

1 

I 

I 

I N otch Peak limestone 1900' + 

I 

I 

I 

I 

I 

FIGURE 380.3.-Section of stromatolites showing upward con250 vex-ity of laminations. 

II I I I I I I 

I I I I I 

I I I I I 

I I I I I I I 

c I r I I I 500 

I I I I 

------ c orset Spring shale 90' --

I I I 

X I I I J ohns Wash limestone 190' 

I I I ~-- ------~ s hale member 

X I 1 I 

1 1 I I 

I I I I 0 

I I I I I rr formation !IOU' 

I 1 1 J 

l l 1 I I 

I I 

l 1 I I 

I I I I I 

II T T T I I I I 

1 1 T I I 

I I I I I I w eeks limestone (upper part) 

X- Stromatolites Modified from Bentley (1958) and 

Drewes and Palmer(l957) 

FIGURE 380.2.-Upper Cambrian sequence in Tule Valley and 

House Range, Utah, showing stromatolite occurrences. 

FIGURE 380.4.-Plan view of stromatolites showing concentricity 

of laminations. 

In the southern part of West Shoreline Butte (fig. 

380.1) the upper 500 feet of the Notch Peak limestone 

(fig. 380.5) consists (in ascending order) of about 100 

feet of massive limestone made up almost entirely of 

stromatolites; 200 feet of interbedded fine-grained 

platy limestone, well-bedded coarse-grained detrital 

limestone, fiat-limestone-pebble conglomerate and two 

stromatolitic biostromes 10 and 30 feet thick; and 200 

feet of massive limestone made up almost entirely of 

stromatolites. The bedded limestone of this section can 

be traced northeastward for a few hundred yards into 

massive stromatolitic limestone so that the entire upper 

... 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-247 

16 miles 

Four miles 

southeast of 

Notch Peak 

Stromatolitic 

limestone 

18 miles 

FEET 

[00 

Non-stromatolitic 

limestone 

Fourteen miles 

south of 

U.S. Highway 6 

FIGURE 380.5.-Schematic diagram showing inferred relationship of massive stromatolitic limestone to nonstromatolitic 

carbonate rocks within the upper part of the Notch Peak 

limestone. 

500 feet of the Notch Peak is made up of massiVe 

stromatolitic limestone. 

Thin sections show that the stromatolites are made 

up of very fine grained limestone with the laminations 

manifested as barely perceptible increases in grain size. 

Sparce ( < 1 percent) subangubr silt-sized quartz 

grains are incorporated in the stromatolites. The 

detrital limestone filling the space between stromatolites 

consists of coarse sand to grit-sized rounded clasts of 

very fine texture. These clasts contain sparse fragments of brachiopods and trilobites. 

Kenji Konishi of the U.S. Geological Survey has 

identified the stromatolites with the form genus and 

form species Oollenia frequens Walcott. Oncolites 

found in association with the stromatolites were assigned to the form genus Pyonostroma by Konishi, who 

indicates that the Pyonostroma suggest a shallow 

marine environment-depths of one-third to 2 m-and 

that 0. frequens may suggest an intertidal environment close to lower tide level. Examination of thin 

sections of the stromatolites by Preston E. Cloud has 

disclosed the presence of filamentous algal material. 

According to Cloud (oral communication) this indicates that the stromatolites lived in shallow (<10m) 

marine waters. 

In the southern part of West Shoreline Butte parts 

of the stromatolitic masses are irregularly eroded and 

overlapped by detrital limestone. The irregular erosion surface-coupled with the concept of a shallow 

marine origin of the stromatolites-suggests that the 

erosion surface was produced by wave action. 

Limestone beds laterally continuous with the stromatolite masses contain zones of limestone pebble 

conglomerate believed to be derived in part from the 

stromatolites. These zones also indicate that fragmentation of the stromatolites and deposition of the nearby 

bedded limestone were essentially continuous. In brief, 

the stromatolites in the area of West Shoreline Butte 

formed reeflike bodies which were periodically fragmented by wave action and overlapped subsequently 

by detrital limestone derived from nearby areas. 

In an area 4 miles southeast of Notch Peak in the 

House Range, the upper 500 feet of the Notch Peak 

is predominantly bedded limestone with only the topmost 160 feet of the formation made up of uniformly 

massive stromatolitic limestone (fig. 380.5). This 

change is due entirely to facies variation, for the thickness of the Notch Peak in the Shoreline Buttes is 

comparable with that in the House Range. 

Still farther south in the House Range-14 miles 

south of U.S. Highway 6-stromatolites are confined to 

a zone of reefs perhaps 40 feet thick about a hundred 

feet or so below the top of the Notch Peak limestone 

(fig. 380.6). There, bedded limestone beneath the reefs 

FIGURE 380.6.-Stromatolitic reefs in the upper part of the Notch 

Peak limestone, 14 miles south of U.S. Highway 6, southern 

House Range. 

is bowed downward .indicating that accumulation of 

carbonate was greater at the reef site than in adjacent 

areas. Bedded detrital limestone and carbonate-pebble 

conglomerate overlap the reef and are bowed upward 

above it, indicating that the stromatolites projected 

above the depositional interface of surrounding areas 

and were reeflike. 

In detail the relationship of the main body of stromatolitic limestone to the bedded limestone between the 

three localities just described is obscure because of 

limited outcrop. The bedded limestone ·in the upper 
D-248 GEOLOGICAL . SURVEY RESEARCH 19 61 

·part of the Notch Peak formation of the House. Range 

is very similar to that at vVest Shoreline Butte, and at 

the latter locality the bedded limestone passes into a 

reeflike body of stromatolitic limestone which is part 

of a still thicker stromatolitic mass (fig. 380.5). Possibly this larger body of stromatolitic limestone is also 

· reeflike, but additional mapping in the House Range 

will be necessary to resolve this question. 

REFERENCES 

Bentley, C. B., 1958, Upper Cambrian stratigraphy of western 

Utah; Brigham Young Univ. Research Studies, v. 5, no. 6, 

70 p. 

Drewes, Harald, and Palmer, A. R., 1957, Cambrian rocks of 

southern Snake Range, Nevada: Am. Assoc. Petroleum 

Geologists Bull., v. 41, no. 1, p. 104-120. 

'Valcott, C. D., 1908, Cambrian sections of the Cordilleran area: 

• Smithsonian Misc. Oolls., v. 53, no. 5, p. 167-230. 

381. PLEISTOCENE TERRACES ON THE EASTERN SHORE PENINSULA, VIRGINIA 

By ALLEN SINNOTT and G. CHASE TIBBITTS, JR., Trenton, N.J.-, and Tripoli, Libya 

Work done in cooperation with the Commonwealth of Virginia 1 

Pleistocene terraces on the Eastern Shore peninsula, 

Virginia (fig. 381.1) can be delineated fairly well by 

field reconnaissance with the aid of modern topographic 

maps. Earlier studies of the terraces in this area 

(Wentworth, 1930) were made without benefit of such 

maps, so that the extent and correlation of terraces had 

to be somewhat generalized. 

The Columbia group of terrace formations of Pleistocene age consists of a succession of thin very gently 

sloping marine and estuarine formations that overlie 

the Tertiary sedimentary rocks of the Virginia coastal 

plain (table 381.1). The terraces discussed here are 

considered to be the emerged upper surfaces of some of 

these formations. 

The terraces listed in table 381.1 are well developed 

at many places on the mainland part of the coastal 

plain, but only the younger ones are represented on the 

Eastern Shore peninsula. From oldest to youngest 

these are the Chowan, Dismal Swamp, and Princess 

Anne terraces, as defined by Wentworth (1930). 

TABLE 381.1.-Terraces of the· Atlantic Coastal Plain 

Terrace (youngest at top) 

Princess Anne (may include Silver Bluff) _______ _ 

Dismal Swamp (Pamlico) ___________ .- _________ _ 

Chowan (Talbot) ____________________________ _ Penholoway _________________________________ _ 

Wicomico ________________________ · ___________ _ 

Sunderland _________________________________ _ 

Coharie _____________________________________ _ 

Brandywipe _________________________________ _ 

Approximate 

altitude of shoreline (feet) 

15 

25 

45 

70 

100 

170 

215 

270 

1 !This paper is ba,sed on work done during a Federal-State cooperativ~ 

program that was terminated in June 1957. 

Some sediments that may be pre-Chowan in age 

underlie several areas having altitudes above about 45 

feet. These areas have altitudes of 60 to 70 feet along 

Butlers Bluff on the southwest shore, about 7 miles 

SSE. of the town of Cape Charles, and they have altitudes of 45 to 60 feet at two other places in the upper 

peninsula in Accomack County. Sediments at these 

levels probably represent Penholoway or Wicomico terrace remmants; they are sh()wn as pre-Chowan on 

figure 381.1. 

The shoreline of the Chow an terrace (Stephenson, 

1912) is about 45 feet above ·present sea level in Virginia. It rises gently from the scarp above the 25-foot 

shoreline of the Dismal Swamp terrace (Wentworth, 

1930). The Chow an terrace is probably equivalent to 

the Talbot terrace as defined by Shattuck ( 1906) from 

the coastal plain of Maryland; Cooke (1931; 1935) 

retains the name "Talbot." 

The Pamlico terrace in North Carolina, first described 

by Stephenson (1912), was later subdivided by Wentworth ( 1930, p. 69) into the Dismal Swamp (upper) 

and Princess Anne (lower) terraces. The Dismal 

Swamp terrace, whose shoreline is about 25 feet above 

present sea level, is therefore equivalent to the Pamlico 

as originally defined by Stephenson. In regional 

papers, Cooke ( 1931; 1935) and most other workers 

prefer the name "Pamlico." 

The shoreline of the Princess Anne terrace, which 

probably represents a late Pleistocene stand of the sea, 

is about 15 feet above sea level. Near the present 

shores of the peninsula, particularly on the bay side, the 

terrace descends in places to very low cliffs above the 

beaches (fig. 381.2). The Princess Anne terrace may 
SHORT PAPERS IN THE GEOLOGI'C AND HYDROLOGIC SCIENCES, ARTICLES 293-435 

Cape 

Charles 

76"00' 

0 

75"30' 

EXPLANATION 

Landward boundary of marshes of Recent age (R) 

,-- --------" 

Shoreline of Princess Anne terrace (PA) ' 

___ ,..,--

Shoreline of Dismal Swamp terrace (DS) 

DS-PA, areas mapped as Dismal Swamp-Princess 

Anne terraces, undifferentiated 

... _ ... .....--... 

Inferred shoreline of Chowan terrace (Ch) 

Pre-Ch, surfaces mapped as older than Chowan terrace 

5 10 MILES 

l!"''IOUIU<~ 381.1.-l\fap of the Eastern Shore peninsula, Accomack and Northampton Counties, Va., showing 

Pleistocene terraces. 

604403 0-61--17 

D-249 
·D-250 GEOLOGICAL SURVEY RESEARCH 1 9 61 

' .. 

FIGURE 381.2.-Low wave-cut cliff truncating Priucess Anne 

terrace on beach south of Occahannock Creek, about 6 miles 

west of Exmore, Northampton County, Va. 

be equivalent, in part, to the Silver Bluff terrace farther 

south, described by several workers (Parker and Cooke, 

1944; Cooke, 1945; MacNeil, 1950). 

Tlie present study indicates that the Chowan terrace 

extends the entire length of the peninsula and is flanked 

by remnants of the Dismal Swamp and Princess Anne 

terraces. 

In the southern half of Northampton County, the 

Dismal Swamp terrace is generally present aa a narrow 

remnant between the more extensive Princess Anne and 

Chowan terraces. There, the scarps above the Princess 

Anne and Dismal Swamp terraces have been consider· 

ably modified by subaerial erosion and in many places 

are obscure. At the extreme southeastern part of the 

peninsula they are absent. 

Along the eastern part of Accomack County and 

part of northwestern Northampton County, the shore· 

line of the Princess A1me terrace has been greatly 

obscured or obliterated by erosion. At these places, 

the areas corresponding to the younger Pleistocene terraces have been mapped on figure 381.1 as Dismal 

Swamp-Princess Anne terraces, undifferentiated. 

At Assawoman Creek, in northeastern Accomack 

County, the writers observed what appears to be an 

estuarine phase of the Princess Anne terrace developed 

upstream at the expense of the Dismal Swamp terrace. 

At this locality a pronounced local scarp rises from the 

Princess Anne directly to the Chowan terrace level. 

A scarp between the Recent shoreline and the youngest Pleistocene (Princess Anne) terrace commonly is 

distinct along the bay side of the peninsula (fig. 381.2). 

Along the ocean side, lagoons have formed behind 

advancing bay-mouth bars and sediment has begun to 

fill in many of the lagoons, resulting in salt-water 

marshes. The Princess A1me terrace is considered to 

begin along the landward edge of the marshes. 

The writers agree generally with Wentworth ( 1930, 

p. 114) that relatively little of what is now the Eastern 

Shore peninsula was land area in pre-Chowan time. 

Thus, essentially all of the present land forms were 

developed during Chowan (Talbot) time and later. 

REFERENCES 

Cooke, C. W., 1931, Seven coastal terraces in the southeastern 

United States: Washington Acad. Sci. Jour., v. 21, p. 503-

513. 

--1935, Tentative ages of Pleistocene shore lines: washington Acad. Sci. Jour., v. 25, no. 7, p. 331-333. 

--1945, Geology of Florida : Florida Geol. Survey Bull. 29, 

339 p. 

)lacNeil, F. S., 1950, Pleistocene shore lines in Florida and 

Georgia: U.S. Geol. Survey Prof. Paper 221-F, p. 95-106. 

Parker, G. G., and Cooke, C. W., 1944, Late Cenozoic geology of 

southern Florida, with a discussion of the ground water: 

Florida Geol. Survey Bull. 27, 119 p. 

Stephenson, L. W., 1912, Quaternary formations, in The Coastal 

Plain of North Carolina: North Carolina Geol. and Econ. 

Survey, v. 3, p. 266-290. 

Shattuck, G. B., 1906, Pliocene and Pleistocene deposits of 

Maryland: Maryland Geol. Survey, 291 p. 

Wentworth, 0. K., 19301 Sand and gravel resources of the coastal 

plain of Virginia : Virginia Geol. Survey Bull. 32, 146 p. 

832. STRATIGRAPHIC SIGNIFICANCE OF THE CRETACEOUS FERN TEMPSKYA IN THE WESTERN 

CONTERMINOUS UNITED STATES 

By CHARLES B. READ and SIDNEY R. AsH, Albuquerque N.Mex. 

The genus Tmnpskya Corda (1845; Kidston and 

Gwynne-Vaughan, 1911) is a representative of an extinct group of leptosporangiate ferns that occur at 

numerous localities in the younger Mesozoic rocks of the 

western conterminous United States, as indicated on 

the index map, figure 382.1. Remains of the several 

known species of the genus consist of silicified masses of 

stems and roots organized into composite stems or 
SHORT PAPERS IN THE GEOLOGlC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-251 

0 100 200 MILES 

FIGURE 382.1.-Index map showing general location of occurt·ences (X) of 'J.'empskya spp. in western conterminous 

United States. Localities where silicified remains have 

clearly been reworl{ed from Cretaceous rocks into later 

g1:avels are not shown. Numbers refer to localities mentioned in the text and in figure :382.4. 

trunklike masses that have been called false stems or 

false trunks (fig. 382.2). The nature of the leaves or 

fronds is unknown. 

The individual stems of the composite structure are 

dichotomous branches of a single plant. The stems are 

so]enostelie and dorsivent.raJ, two row~ of alternate 

leaves being bol'ne on the morphologically upper surfaces as shown in .figure 382.3. Both upper and lower 

surfaces al'e 1narked by adventitious root insertions. 

The xylem. of the solenostele is exarch and the stele is 

charn.cter.ized by both external and internal phloem. 

The roots are small and diarch. Masses of these roots 

appen.r to have constituted a feltlike matrix during the 

FIGURE 382.2.-Sketch of a transversely cut false stem of 

Ternpskya grandis Read and Brown showing the radial 

orientation of the dorsi ventral stems. 

life of the plant in which the freely branching stem 

system was embedded. Even though both individual 

stems and roots are relatively small in diameter, the 

false stem may have had sufficient strength and rigidity 

so that it stood erect to a height of a few feet in some 

species and resembled a low tree fern in general habit 

(Andrews and !(ern, 1947; Read and Brown, 1937). In 

other species· it is possible that the growth form was 

that of a vine (Read and Brown, 1937). 

The species of Ten~pskya that are known from the 

younger Mesozoic rocks of the western part of the 

United States are T mnpskya graooi8 ·Read and Brown 

(1937), T. knowltoni Seward (1924), T. minor Read 

and Brown (1937), T. suzJerba Arnold (1948), T. wesselii Arnold ( 1945), and T. wymningensis . Arnold 

( 1945). l\iaterial that appears to represent new species 

has recently been discovered in rocks of Cretaceous age 

in the Big Hatchet and Animas Mountains of southwestern New Mexico (Zeller and Read, 1956) . 

Representatives of the genus Tempskya occur at 

several localities in New Mexico, Idaho, 1-Vyoming, and 

Montana where either the containing strata or those 

immediately adjacent are marine. Data regarding 

these occurrences are presented in figure 382.4A, which 

shows the accepted age relations of the Tempskyabearing rocks. In 1957 J. B. Reeside, Jr., made many 

collections of marine in vertebrates associated with 

Tentpskya in the Big Hatchet Mountains, and Zeller 

and others have supplemented the collections. The 

various groups of organisms have been examined by 

several paleontologists,- and digests of their findings follow (written communications, 19.55 to 1959) : 
D-252 GEOLOGICAL SURVEY RESEARCH 19 61 

f 

e 

g 

FIGURE 382.3.-Diagram of a transverse section of a stem of 

Tempskya grandis Read and Brown showing the general 

characteristics of the dorsi ventral stem: a, pith; b, stele; c, 

cortex; d, insertion of adventitious root; e, leaf traces in early 

stages of development; f, leaf traces in more advanced stages 

of development; g, adventitious root. 

Collections from 30 feet above the horizon containing 

Tempslcya in sec. 20, T. 32 S., R. 15 1V.: 

John B. Reeside, Jr.-Mollusks are of "middle Washita and late 

Albian age.'' 

Ruth Todd-Smaller Foraminifera are of "Washita age.'' 

N. F. Sohl-Gastropods are of "late Fredericksburg (middle 

Albian) age.'' 

Collection from 10 feet below the horizon containing 

Te'mpskya in sec. 20, T. 32 S., R. 15 W.: 

N. F. Sohl-Mollusks ar.e of "late Fredericksburg to early late 

Washita age." 

Collection from 300 feet below the horizon containing 

Ternpskya in sec. 20, T. 32 S., R. 15 W.: 

John B. Reeside, Jr.-Mollusks are of "Washita age." 

Collection fron1 strata adjacent to those containing 

Tempskya in sec. 13, T. 31 S., R. 18 W.: 

·w. A. Cobban-Foraminifera and mollusks are of "late 

Comanche (Washita) age (late Albian).'' 

The ammonite Neogastroplites, which is considered 

to be probably of late Albian age by Reeside and Cobban 

(1960, p. 30), has been collected from Tempskya-bearing 

formations or frmn overlying formations in several 

parts of the western United States as summarized 

below: 

1 N eogastroplites and T wmpskya spp. were reported 

from the Aspen shale in southwestern 'Vyoming near 

localities 3, 4, 5, and 6, and from the Thermopolis 

shale near locality 7, figures 382.1 and 382.4A (Reeside and Cobban, 1960, p. 30-31) . 

2 N eogastroplites and T wmpskya knowltoni are found 

in the undifferentiated zone below the Big Elk sandstone member of the Colorado shale in the upper part 

of the Musselshell Valley at locality 8, figures 382.1 

and 3"82.4A (Reeside and Cobban, 1960, p. 1727). 

3 N eogastroplites has been collected from sandy beds 

that directly overlie the Tempskya knowUoni-bearing 

Vaughn bentonitic member of Blackleaf formation 

(so called ~'red speck zone") in northwestern Montana 

at locality 9, figures 382.1 and 382.4A (Reeside and 

Cobban, 1960, p. 17). . 

All the species of Te1T~>pskya appear to have been land 

plants and at several localities the containing strata 

are dominantly nonmarine. Figure 382.4B summarizes 

the known nonmarine occurrences in Mesozoic strata 

other ·than those in which it is clear that specimens 

have been reworked into younger strata. 

In a letter dated February 14, 1956, prior to his visit 

to southwestern New Mexico, Reeside summed up his 

opinion regarding the stra,tigraphic significance of 

Tempskya in the following wordsRegarding the age of Tempsk11a, I think you are right about 

puttin.g it in the Albian. There is no undisputed evidence of 

later age for the American records and much in favor of 

Albian. 

Reeside indicated in subsequent discussions that his 

field observations in New Mexico confirmed his pre viously written opinion. 
: 

-

SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-253 

STANDARD CLASSIFICATION NEW MEXICO IDAHO-WYOMING WYOMING MONTANA 

BIG HATCHET MOUNTAINS CENTRAL SOUTH- UPPER PART OF NORTHWESTERN PART 

AND ANIMAS MOUNTAINS EASTERN WESTERN BUFFALO AREA MUSSELSHELL VALLEY after CObban and others, 1959 Sarlos EUROPEAN STAGES IDAHO WYOMING 

Localities 1 and 2 Locality 3 · Localitoes Locality 7 Locality 8 Locality 9 4 5 and 6 

(/) J..JJ-lj)_l?lJ-ll.U l :I .§ .~i 

ffi~~ Frontier Shales equivalent to a:~ Floweree Frontier .. ~ 

CENOMANIAN Conglomerate and sandstone formation 

~ the Greenhorn and 

~ Shale .... member D.<< formation Belle Fourche -~ii 

~l;j~ present only locally (part) IOJ: 

e formations .e ~ .. a: LL. .. • u 

·TIDJ D?LTDD::r ~ "-"...c ]J:l D1

J TI I D -- . . 0 Big Elk sandstone mbr Bootlegger mbr Aspen shale Aspen shale Mowry shale -g 

5 .... c: . • Vaughn bentonitic mbr 100 

• Ther:noP· I 8 ~; Newcastle ss Shale and sandstone "''" . member ue Taft Hill <:_ Interbedded sandstone, Bear River Bear River olis shale I Skull Creek sh .!!!~ glauconitic mbr ~ ALBIAN shale, and clay formation formation m,E 

p Cloverly form'ation a: "First Cat Creek sand" Flood mbr 

~ 

mrm 

-? -

(/) JJ~ Tl rrrtriD;rru 1 r1 .11 'TTn;rmrn :I - - . - r- - 0 

LIJ ? u 

< Cloverly formation l;j 

a: 

u 

a: Beckwith LIJ .......... ,.....-1"'---?-r-...-r--,_. :c: Massive and formation Kootenai Kootenai 0 thin bedded Gannett formation formation -I APTIAN limestone group 

A. LOCALITIES WHERE TEMPSKYA SP. HAS BEEN REPORTED IN ASSOCIATION WITH MARINE INVERTEBRATES 

STANDARD CLASSIFICATION NEVADA UTAH-COLORADO ARIZONA IDAHO WYOMING, 

SOUTHEASTERN PART SE UTAH-SW COLORADO FOUR CORNERS AREA SOUTHEASTERN PART COKEVILLE-AFTON REGION Series EUROPEAN STAGES 

Locality 10 Localities 11,12, and 13 Locality 14 Localities 15 and 16 Locality 17 

(/) 

:I Mancos shale Mancos shale 

ffi8~ CENOMANIAN . g;~~ Upper sandstone mbr Upper part Porcellanite, shale, 

sandstone, limestone, :I l;j _. r- ..... .-...... ? - - .... .--r-....... ?.. ...- minor coal beds; a: ,..... ? ......... _ u - ...... .... mostly nonmarine .... _ -? ...... """-............. '-"' .. 

c: . . 0 Wayan formation ~ Overton fanglomerate '0 

.. c: 

...... ,.....-r--_.,.....?r-- ............ -r-..... c: ::1 Red shale and ~ .. D"' oholo, > V""""' ~ Bear River sandstone 

ALBIAN '0 .......... ~.-- ...... ?·,L.,.--..._ -- ...... ? L- p formation ~~:~~~i~e shales 

~ .. ...... Tygee ss a: 

< .. . 0 . Coal·bearing Lower part J)::(IJ::(f?.,_Dark shale Dark shales ~ ~ member ?L 1 J :1 :1 toJ:u1JJlr1lr (/) .. . - :I 0 r- .... ,--r- ? ...... ,.....-r- 0 

LIJ 

u 

< l;j Conglomerate 

a: ...... ~--' ..... - ?- member u 

a: 

LIJ Gannett 

:c: Unnamed fanglomerate, ..-- ?,......- ...... ,.....-r- group Gannett 

0 APTIAN grit, and shale r- group -I 

Mrrrnmn 

B. LOCALITIES WHERE TEMPSKYA SP. HAS BEEN REPORTED IN NONMARINE STRATA 

FIGURE 382.4.-Correlation of parts of the Cretaceous system at selected localities in the western conterminous United 

States showing rock sequences at localities where Tem1J81.;ya spp. has been reported. Formations containing Tempskya 

are marked by an nsterisk ( •). Locality numbers in headings of columns are shown on figure 382.1. Correlations 

·nfter Cob bun and Reeside ( 1952a) and Reeside and Cobban ( 1960). 
D-254 GEOLOGICAL SURVEY RESEARCH 1 9 61 

Re-examination of earlier information on the stratigraphic occ1urences of the various species of Tempskya 

and consideration of new discoveries indicate that the 

age of the genus is more restricted than was formerly 

thought (Read and Brown, 1937), and that in the 

western part of the United States it is restricted to 

strata that are Albian in age. 

REFERENCES 

Andrews, Henry N., and Kern, Ellen M., 1947, The Id~ho 

Te'Yft1J8kyas and associated fossile plants: Missouri Bot. 

Garden Annals, p.119-186. 

Arnold, C. A., 1944, Silicified plant remains from the Mesozoic 

and Tertiary of western North America. Ferns [Pt.] 1: 

Michigan Acad. Sci., Arts, and Letters, Papers, v. 30, p. 

3-34 [1945]. 

--1958, A new Tempskya: Univ. of Michigan, Mus. Paleontology, Contr., v. 14, no. 8, p. 133-142. 

Cobban, W. A., Erdman, C. E., Lempke, R. W., and Maughan, 

E. K., 1959, Revision of Colorado group on Sweetgrass 

Arch, Montana: Am. Assoc. Petroleum Geologists Bull., v. 

43, no. 12, p. 2786--2796 .. 

Cobban, W. A., and Reeside, John B., Jr., 1952a, Correlation of 

the Cretaceous formations of the Western Interior of the 

United States: Geol. Soc. America Bull., v. 63, p. 1011-1044. 

-- 1952b, Frontier formation, ·wyoming and adjacent 

areas: Am. Assoc. Petroleum Geologists Bull., v. 36, p. 

1913-19~1. 

Corda, A. J., 1845, Flora protogaea; Beitrage zur Flora der Vorwelt: Prague, p. 81-83. 

Kidston, Robert, and Gwynne-Vaughan, D. T., 1911, On a new 

species of Tenvpskya from Russia: Russ.-Kaiserliche Mineralog. Gesell. St. Petersburg, Verh., v. 48, p. 1-20. 

Read, C. B., and Brown, R. W., 1937, American. Cretaceous ferns 

of the genus Tempskya: U.S. Geol. Survey Prof. Paper 

18~F, p. 105-129. 

Reeside, John B., Jr., and Cobban, W. A., 1960, Studies of the 

Mowry shale (Cretaceous) and contemporary formations 

in the United States and Canada: U.S. Geol. Survey Prof. 

Paper 355, 126 p. 

Seward, A. C., 1924, On a new species of Tempskya from Montana, 1.'empskya knowltoni, sp. nov.: Annals of Botany, 

v. 38, no. 151, p.485-507. 

Zeller, R. A., Jr., and Read, C. B., 1956, Occurrence of Tempsl..~ya minor in strata of Albian age in southwestern New 

Mexico [abs.] : Geol. Soc. America Bull., v. 67, no. 12, pt. 

2, p.1804. 

GEOPHYSICS 

383. GRAVITY LOW AT MINTO FLATS, ALASKA 

By DAVID F. BARNEs, Menlo Park, Calif. 

Much of central Alaska consists of .broad alluviumcovered topographic basins, which may also be structural basins, containing Cenozoic deposits of considerable thicknesses. One phase of the Geological Survey's petroleum investigations in this area has been 

the determination of the thickness of these deposits. 

One of the areas studied is the Middle Tanana basin 

(Miller, Payne, and Gryc, 1959) that extends for about 

100 miles both east and west of Fairbanks. The basin 

is divided into two embayments by an upland promontory that extends southward to the town of Nenana. 

Aeromagnetic lines flown south of Fairbanks in 1955 

(Zietz and Wahrhaftig, ·written communication, 1960) 

cross the center of the eastern and larger embayment, 

where they show that pre-Cenozoic basement rocks lie 

within 500 meters of the surface. Recent gravity surveys suggest that a thick section of Cenozoic deposits 

may be present in the western embayment. The first 

indication of this sedimentary section was a -40.6 

Bouguer gravity anomaly recorded at the village of 

Minto (Thiel and others, 1958). Recent gravity surveys 

by the U.S. Geological Survey have defined the form 

and magnitude of this gravity low (fig. 383.1) that 

covers all the broad swampy Minto Flats west of 

Nenana .and extends south of them towards the Alaska 

Range. 

Precambrian rocks of the Birch Creek schist (Mertie, 

1937) crop out along the eastern edge of the Minto 

Flats and form the upland promontory that divides the 

Middle Tanana basin . into two parts. The northern 

and western rim of the flats is formed by hills underlain 

by strongly folded and faulted Paleozoic and Mesozoic 

sedimentary rocks (Capps, 1940). The southern part 

of the Middle Tanana basin slopes upward into the 

foothills of the Alaska Range, where the Nenana gravel 

and the coal-bearing formation of Tertiary age crop out 

(Wahrhaftig, 1958). The structure of these deposits 

shows that folding and faulting during the middle 

Tertiary formed local basins in which as much as several thousand feet of sediments have accumulated 
.,JI' 

SHORT· PAPERS IN THE GEOLOGIC AND. HYDROLOGIC SCIENCES, ARTICLES 293-435 D-255 

~0 

( 

~ I _, _.,-~----- '\ 

- \ ~/ 

'-.....\ 

'--. t _, / 

·5 0 

) 

/ 

' '\ 

• 

,/"' t 

• 

• 

• 

• 

J 

...Y" 

/ 

/ / _____ .... ----

__.. / / / , , 

__ J 

___ 

___ ... -- --- --- - - ------ --~ ( ,.,.t;JtP--:::-:: • , ... 

-- ~__..,-.. .,) --\ .. , _..,, --- ---------..- __ ,. ... ....... ---- _"...:.--J 

-- • 

149° 

5 10 

__.. 

-- ---

15 MILES 

- - EXPLANATION 

Gravity • Station 

---5--

Simple bouguer gravity contours Do shed in n rPns <~f poor r.on· 

trois. Contour intamrl 5 

milli{Jnls 

60Q foot topographic contour 

FIGURE 383.1.-Contour map of simple Bouguer gravity anomaly, Minto Flats, Alaska . 
D-256 GEOLOGICAL SURVEY RESEARCH 19 61 

(vVahrhaftig, 1950). Physiographic evidence (D. M. 

Hopkins, oral communication, 1961) strongly suggests 

that the Minto Flats are actively subsiding, and that 

sediments are accumulating there at the present time. 

Figure 383.1 is a map· of the wester1i part of the 

~liddle T~inana basin. The gravity contours show 

simple Bouguer anomalies computed fr01n observed 

gravity values at Fairbanks (Thiel and others, 1958) 

using a rock density of 2.67. The most important 

features of this map are a broad kidney-shaped low and 

a steep gradient a1ong its eastern side. The -10 mgal 

contour defines the outer edge of the low and approximately coincides with the 600-foot altitude contour, 

which marks the edge of the hills- bordering the Mjnto 

Flats. Bouguer gravity values associated with all the 

hills and lowlands adjacent to the flats range from 

-10 to + 12 mgals except on the southern end of the 

flats where lower· gravity values are associated with the 

Alaska Range. A gravity traverse along the road from 

Fox to Livengood north of the mapped area crossed 

contacts between Precambrian, Paleozoic, and Mesozoic 

rocks but did not reveal any large anomalies. Accordingly, density contrasts within the rocks forming 

the basement complex are probably not sufficient to 

explain the anomaly at Minto Flats. 

A 20 

0 

-20 

-40 

-60 

p= 1.9 gm/cl 

2000 

4000 

1-

UJ 

UJ 

~ 6000 p= 2.3 gm/cl 

~ 

r.~ 8000 1-

a.. 

UJ 

0 10,000 

i2.000 

The gravity low associated with the Minto Flats has 

n, magnitude of - 35 to -55 mgals in relation to the 

surrounding areas. The steepness of the gradient west 

of Nenana indicates that the anomaly has a shallow 

source; its maximum theoretical depth (Bott and 

Smith, 1958) is 3 km. As the gradient approximately 

coincides with a contact at the surface between 

Quaternary deposits and the denser Birch Creek schist, 

this contact may be the source of the anomaly. The 

data do not completely eliminate the possibility, however, that all or part of the anomaly may be caused by 

another shallow basement contact such as the edge of 

the possible mafic rock mass postulated by V\T oollard 

and others ( 1960) in the vicinity of Nenana. Near by 

outcrops, however, do not show such a mafic rock mass. 

The thickness of the sedimentary prism required to 

cause the Minto Flats anomaly depends on the density 

contrast between the sediments and the basement rocks, 

but data for estimating this contrast are scarce. 

Specific gravities of a dozen hand specimens of Precambrian and Paleozoic basement rocks range from 2.6 

to 2.8, but the densities of Cenozoic rocks of the types 

that may be present beneath the Minto Flats vary 

widely with age and character. On one extreme, 

Recent alluvium containing significant amounts of 

Bouguer anomaly 

p=2.7 gm/cl 

basement rocks 

A 

10 

DISTANCE IN MILES 

FIGURE 383.2.----"-0bserved and compu~ed gravity on profile A-A' north of Nenana and suggested subsurface configuration. 
SHORT PAPERS IN THE GEOLOGI·C AND HYDROLOGIC SCIENCES, ARTICLES 2 9 3-4 3 5 D-257 

EXPLANATION 

D 

Quntcrnnry deposits 

66" Tcrtinry scdimcntnry 

rocks 

[I] 

Prc-Tcrtinry rocks 

50 0 50 MILES GeologyafterDulroand 

L......I..--L-....1--.J,......I---- Payne,l957; and un· 

published maps of 

Hopkins and Taber 

FroUJm 38H.:3.-Distribution of Tertiary and Quaternary sedimentary rocl{S in central Alaska. 

either ice or organic ma,tter may be lighter than 1.8; 

and at t·he other extreme, laboratory n1easurements of 

n few hand specimens of water-saturated sandstones of 

Tertiary age from the Yukon-Tanana area were as high 

as 2.6. Thus the thickness of the sedimentary section 

.in l\~[into Flats could ra.nge from one to severn.} kilometers. Figure 383.2 shows n. plot of the anomaly 

alonp: profile A-A' near Nenana and one of the several 

basement configurations that could produce such an 

anomaly. The suggested configuration assumes a layer 

of low-density alluvium overlying a thicker, in~rmediate-density section which is separated from the 

basement. rocks by a normal fault. Such a fault would 

pro:ject very close to the oil seep reported near the 

mouth of t·he Nenana by :Miller and others (1959). 

Some conclusions regarding the age of the deeper 

deposits beneath the Minto Flats may be drawn from 

the rat·het· large thickness required to explain the gravity nnom.aly. The maximum thickness of Quaternary 

alluvium that hns been measured in the Tanana, Valley 

is nbont 250 meters at a seismic station 2 miles south of 

Fn,irbanks, measured by the an.thor in 1952. "Tilliams 

(1960) reports that abont 120 meters of alluvium at 

Fort Yukon nre underlain by late Tertiary deposits. 

Even a 1 km sedimentary section would thus be con-

~.idernbly thicker than nearby deposits of Quaternary 

alluvium, nnd even 1. km of subsidence during Quatermu·y time would represent a rather rapid crustal move-

.... 

ment. Accordingly, older Tertiary deposits are 

probably present in the deeper part of the Minto Flats 

basin. These Tertiary rocks are probably denser than 

Quaternary alluvium so the thickness of the section required to cause the anomaly is proba.bly greater than 1 

km. The subsidence which created the Minto Flats 

basin may have begun at about the same time as the 

subsidence and faulting that created nearby basins in 

which Tertia.ry se~imentary rocks are now exposed. 

Extensive Tertiary deposits (fig. 383.3) are present 

both north and south of the l\1into Flats in the Alaska 

Range (1Vahrhaftig, 1958) and along the Yukon River 

between the Yukon flats and the Palisades (Eakin, 

1913). Coal-bearing rocks are present in the lower parts 

of both the Alaska Range and Yukon Valley Tertiary 

sections, and may also be present beneath the Minto 

Flats. Gravity values a.t the southern end of the Minto 

Flats anomaly are lower than in other bordering areas· 

and suggest that the sedimentary prism may have a 

shallow connection with one of the basins containing 

Nenana grn vel. 

REFERENCES 

Bott, M. H. P., and Smith, R. A., 1958, The estimation of the 

limiting depth of gravitating bodies: Geophy.s. Prosp., v. 6, 

no. 1, p. 1-10. 

Ca.pps, S. R., 1940, Geology of the Alaska railroad region: U.S. 

Geoi. Survey Bull. 907, 201"p . 

Dutro, J. T. and Payne, T. G., 1957, Geologic map of Alaska: 

U.S. Geol. Survey, scale 1: 2, 500,000. 

Eakin, H. l\I., 1913, A geologic reconnaissance of a part of the 

Rampart quadrangle, Alaska: U.S. Geol. Survey Bull. _535, 

38 p. 

)iertie, J. B., 1937, The Yukon-Tanana region, Alaska: U.S. 

Geol. Survey Bull. 872, 276 p. 

)iiller, D. J., Payne, T. G., and Gryc, George, 1959, Geology of 

possible iJetroh~um provinces in Alaska: U.S. Geol. Survey 

Bull. 1094, 131 p. 

~rhiel, Edward, Bonini, W. E. Ostenso, N. A., and Woollard, G. 

P., ~1.958; Grav'ity iueasurements in Alaska: Woods Hole 

Oceanog. Inst. Ref. 58-54, 104 p. 

Wahrhaftig, Clyde, 1950, Physiographic history of .southern 

·Alaska-An hypothesis: Geol. Soc. American Bull., v. 61, 

no. 12, pt. 2, p. 1532. 

---1958, Quaternary geology of the Nenana River valley and 

adjacent parts of the Alaslm Range: U.S. Geol. Survey 

Prof. Paper 293-A, 70 p. 

Williams, J. R., 1960, Cenozoic sedirr~ents ·beneath the central 

Yukon flats, Alaska, in Short pUJpers in the geological 

sicences: U.S. Geol. Survey Prof. Paper 400-B, p. B329. 

'Voollard, G. P., Ostenso, N. A., and Thiel, Edward, 1960, Gravity 

anomalies, crustal structure and geology in Alaska: Jour. 

Geophys. Res., v. 65, no. 3, p. 1021-1037 . 
D-258 GEOLOGICAL SURVEY RESEARCH 1 9 61 

384. GRAVITY SURVEY NEAR TUCSON, ARIZONA 

By DoNALD PLoUFF, Denver, Colo. 

A total of 767 gravity stations were established near 

Tucson, Ariz. D. B. Jackson, A. J. Vaughn, and R.N. 

Babcock assisted in the field operations and reduction 

of the data. This region of the Basin and Range physiographic province is characterized by irregularly 

spaced mountains surrounded by desert plains. 

Three major groups of rock crop out in the mountains located within the area of the gravity survey (fig. 

384.1). The intrusive rocks include granite, granodiorite, and related crystalline rocks of Preca.mbrian, 

Cretaceous, and Tertiary age. The Paleozoic and 

Mesozoic rocks mainly include a wide variety of sedimentary and volcanic rocks. The rocks of Tertiary age 

also include several types of sedimentary and volcanic 

rocks. A samp1ing program to determine the densities 

of the rock types in this area is being conducted. 

The observed gravity measurements were referred to 

the absolute value of 979,227.2 mgal (milligals) at the 

Tucson l\iunicipal Airport (Woollard, 1958, p. 532). 

A standard rock density of 2.67 g per cm3 was assumed 

for calculation of the elevation and terrain corrections. 

Terrain corrections were carried to 18 miles, using the 

U.S. Coast and Geodetic Survey system (Swick, 1942). 

The Bouguer gravity anomaly map (fig. 384.2) shows 

significant correlations between gravity highs and outcrops of Tertiary and older rocks. Many of these correlations can be attributed to the contrast in density 

between the rocks cropping out in the mountains and 

the less dense alluvium of the intervening valleys. 

Highs correlated with the outcrops are at localities A, 

B, 0, E, and F (figs. 384.1 and 384.2). Relative gravity 

lows that are associated with thick alluvium deposits 

are at localities G, H, J, K, and L (figs. 384.1 and 384.2). 

The gravity anomaly pattern enclosing the Tucson 

Mountains (loc. A) is markedly linear; this linearity 

suggests that the mountain area is bounded by faults. 

The gravity pattern in the Sierrita J\llountains, (loc. B)~ 

however, does not have such striking linear boundaries, 

and, moreover, the gravity high is 6 miles northwest 

of the topographic high. The elongate gravity high is 

N 

1 

32030'.---=-E-X P::-L-:A_N_A=-TI_O_N ---,,---------,---------, 

----/00-

Contour, showino gravity in milliools 

oshed where inferred 

IntervalS milliools 

INDEX MAP OF ARIZONA 

110°45' 111°30' 111°15' 

0 10 Ill 20 MIL!S 

FIGURE 384.1.-Geologic map (generalized from Wilson and 

others, 1960). Localities mentioned in text indicated by 

capital letters. 

0 10 15 20 MILES ~--~---L--~--~ 

FIGURE 384.2.-Bouguer gravity anomaly map. Localities mentioned in text indicated by capital letters. 
SHORT PAPERS IN THE GEOLOGI·C AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-259 

along a northwestward-elongated band of Cretaceous 

and older sedimentary rocks. 

The gravity lows at localities G and H, are about 

4 miles east of the topographic low along the Santa 

Cruz River. Interpretation of the thickness of alluvium in this area is complicated by the uncertain distribution beneath the alluvimn; the Helmet fanglomerate, of Tertiary age, is about 10,000 feet thick in this 

area (Cooper, 1960). The density of the fairly to moderately well indurated conglomerate, which comprises 

most of the Helmet .fanglomerate, is about 2.4 to 2.5 

g per cma, according to preliminary density measurements. This density probably is intermediate between 

that of the alluvium and the pre-Tertiary rocks of the 

area. 

REFERENCES 

Cooper, J. R., 1960, Some geologic features of the Pima mining 

district Pima County, Arizona: U.S. Geol. Survey Bull. 

1112-C, p. 63-103. 

Swicl\:, C. H., 1942, Pendulum gravity measurements and isostatic reductions: U.S. Coast and Geodetic Survey Svec. 

Pub. 232, 82 p. 

"rnson, E. D., Moore, R. T., nnd O'Haire, R. T., 1960, Geologic 

map of Pima and Santa Cruz Counties, Arizona: Arizona 

Bur. Mines, Tucson. 

Woollard, G. P., 1958, Results for a gravity control network at 

airports in the Uni.ted States: Geophysics, v. 23, no. 3, 

p. 520-535. 

385. ELECTROMAGNETIC STUDIES IN THE TWIN BUTTES QUADRANGLE, ARIZONA 

By F. C. FRISCHKNECHT and E. B. EKREN, Denver, Colo. 

Electromagnetic measurements of the Helmet fanglomerate of Tertiary age (Cooper, 1960, p. 77-89) a.nd 

surrounding rocks in the Twin Buttes quadrangle near 

Tucson, Ariz., give some information on the feasibility 

of pt·ospecting for minerals in the older bedrock beneath the f.Ielmet formation, and the usefulness of electromagnetic methods in resolving structural problems 

in this area. 

The generalized geology of the area in which electromagnetic measurements were made is shown on figure 

885.1. The I:Ielmet fanglomerate dips steeply to the 

southeast .in the tnt verse areas. According to Cooper 

(1960, p. 01), t·he fanglomerate is poorly sorted and 

contn.i ns pebbles, cobbles, and boulders of variegated 

material in a silt matrix. The 'most prominent structural feature in the area is the San x~ivier thrust fault. 

Conventional tunun measurements (Hedstrom, 1940) 

were rna de along traverses normal to a long grounded 

wire, using a coil spacing of 100 feet and a frequency 

of :300 cycles per second. The turam ratios were nornmlized nnd the amplitude and phase angle of the normalized field were computed from the ratios, assuming 

value~ of 1.00 and 0° for the amplitude and phase angle, 

respectively, at a distance of 100 feet from the cable. 

The result-s of the tr~tverse in the northward direction 

are shown on figure 385.2. In general, the ratio curves 

are displaced considerably from their free-space values 

of 100 percent and 0 percent. Also, the ratio curves 

display discrete anomalies, which show that individual 

beds ,\'ithin the Helmet vary considerably in resistivity. 

Had a smaller coil spacing been used these anomalies 

might have been more pronounced. However, despite 

local lat~ra.I v~triations in resistivity, the turam amplitude and phase angle curves closely follow the theoretical curves for the field about an infinite wire on a conducting homogeneous half-space ('Vait, 1953). The 

measured values of amplitude and phase angle are compared on figure 385.2 with theoretical curves chosen to 

fit the measured points best. The best fits for the amplitude and the phase angle curves differ, as indicated 

by the displacement between the points where ( up.w) ~r= 

2.0 on each curve. For any distance along the measured curves, there is a corresponding value of ( UJ.tw) g,r= 

2.0 on the theo.retical curves, making it possible to calculate an "apparent" resistivity. For exaJnple, a.t the 

point where ( uJ.tw) ~~r= 2.0 on the theoretical amplitude 

curve, the distance 'I' on the measured curve is 512 feet. 

The ~tppa.rent resistivity is then calculated to be 24 ohmmeters. Similarly, for the phase angle curve the resistivity is 16 ohm-meters. 

Variable frequency measurements, or depth soundings, were made at eight different locations (fig. 385.1). 
D-260 (}EOLOGICAL SURVEY RESEARCH 1 9 61 

0 6000 

Geology generalized from 

Cooper ( 1960) 

12,000 FEET 

~----------~------------~ 

EXPLANATION 

Alluvium 

~~~11111fii1~i111il Helmet fanglomerate 

l ~ >- t-0:: 

ct:< 

::JZ 

0 

• l

'lfl 

;:::J 

UJO 

O::UJ 

Sedimentary-volcanic sequence u u 

Sedimentary rocks 

Granite 

]

6 u UJ-

...JO 

ct:N 

a.. 

,A...J;.. __ _ 

Thrust fault 

Teeth on upper plate 

,.11_ 

--- D Fault 

Dashed where approximately 

located. U, upthrown side; 

D, downthrown side 

i 

I 

I 

El 

Variable frequency 

transmitting coil 

S-4 

Station number 

FIGURE 385.1.-Geologic map of part of the Twin Buttes quad~ 

rangle, Arizona; showing location of electromagnetic traverses. 

A 

0.9~1itude 

M ~~:~e 0.7 ase a gle ·~ 0 

.... 

0 

0.6 ~ 

~ 0.5 ~ 

a.. 

:E 

oC( 0.4 .... 

> 

i= 

oC( 

.:;:: 0.3 a: 

0.2 

(al'w)'l2 r= 2.0 

e Measured amplitude 

" Measured phase angle 

Theoretical curve 

STATION DISTANCE FROM CABLE. IN FEET 

-10 

-20 

tJ) 

-30 tti 

a: 

-40 ~ 

z 

-50 ; 

-60 " ~ 

.... -70 ~ J: 

a.. 

1-

-20 a: ~ .... 

a.. -10 ~ 

0 Q 

~ a: +10 .... 

tJ) 

oC( 

~ 

0 

~ 

:::> 

0 

FIGURE 385.2.-Turam ratio and field curves for a traverse northward from long grounded cable. Because of attenuation of 

the signal beyond station distances of 1,500 feet from the 

cable, only results from the nearer part of the traverse are 

shown. The traverse in the southward direction yielded 

similar results. 

Two large loops were placed on the ground; one was 

energized by a 70-watt power amplifier and the other 

served as a receiving coil (Keller and Frischknecht, 

1960). A ratiometer was used to measure the mutual 

impedance between the coils over a frequency range 

of 35-1200 cycles per second. 

Sounding S-3 was located near the cable used for the 

turam measurements, and a coil spacing of r= 1,350 feet 

was used. One coil for S-8 was several hundred feet 

north of the south edge of the San Xavier thrust; the 

other coil was 1,400 feet north of the first. The amplitude ratios for S-3 and S-8 were fitted on figure 385.3 to 

the theoretical curve (after W a;it, 1955) for the mutual 

coupling between loops on a homogeneous half-space. 

The data for S-3 and S-8 closely fit the theoretical 

curve, indicating that in gross behavior the Hebnet 

is an electrically homogeneous medium to a depth of at 
I. 

SHORT PAPERS IN THE GEOLOGI·C AND HYDROLOGIC SCIENCES, ARTICLES 2 9 3-4 3 5 D-261 

10.0 

~ 

3 

.::l.. 

8.0 

6.0 

5.0 

4.0 

3.0 

~ 8.0 

0.6 0.5 0.4 0.3 

)(0 

I 0 t 80 cps po;nt, stat;on S-7 

80 cps point. station S-4 

\ 

0 

~-­ ~0 

~"' -rr=O /)1,0 

r ~)( 

.,('(j) 

0/ 

)(/ 

I 

0/ 

-~r 5 

:~ 80 cps point. station S-8 

~80 cps po;nt, staHon S-3 

1.2 1.0 0.8 0.6 0.5 0.4 

MUTUAL IMPEDANCE RATIO jZ/zol 

11-.IOURI!l 385.3.-V nrinble frequency measurements an4 matching 

t:heoretlcnl curve for stntions S-3, S-8, S-4, and S-7. 

least several hundred feet. The scatter in the measured values rep1~esents instrumental errors. 

Apparent resistivities can be determined from the 

variable frequency loop measure1nents, as from the 

turam Ineasurements, by the positions at which the 

measured curves fit the theoretical curves ( l{eller and 

Frischknecht, 1960). For S-3 the apparent resistivity 

is 28 ohm-meters and for S-8 it is 24 ohm-meters. 

Four soundings were made along a north-south traverse between the easternmost of the Twin Buttes and 

the Sahua.rita road (fig. 385.1) in order to loca,te the San 

Xavier thrust fault. .1\{easurements from two of these 

soundings, S-4 and S-7, with coil spacings of 1,350 and 

1,450 feet, respectively, are plotted on figure 385.3. Few 

theoretical curves for this type of sounding over layered 

earth are available, and the scatter of the data is too 

great to permit an accurate interpreta.tion. The values 

for S-7 approximately fit the theoretical curve for loops 

raised above a homogeneous half-space a distance h, 

where h=0.21·, implying a relatively resistant surface 

layer 200 or 300 feeL thick, underlain by more conductive rocks. From calculations for loops raised above 

the surface it may be inferred that the theoretical curve 

for loops on the surface of a conducting layer that 

has .an insulating half"-space beneath also is probably 

flatter than the curve for a homogeneous half-space. 

The latter is the more likely, because in this area a layer 

of alluvium probably is underlain by granite or limestone. 

Apparent resistivities of the Helmet fanglomerate, as 

detennined by electromagnetic measurement, are somewhat lower (16 to 28 ohm-meters) than those deternlined from electric logs (35 to 60 ohm-meters, G. V. 

l{eller, oral communicatibn, 1960). Because of its low 

resistivity and because of local variations in resistivity 

the Helmet would be a formidable obstacle in trying 

to locate possible underlying ore bodies by electromagnetic methods. 

REFERENCES 

Cooper, J. R., 1960, Some geologic features of the Pima mining 

district, Pima County, Arizona: U.S. Geol. Survey Bull. 

1112-C, p. 63-103. 

Hedstrom, Helmer, 1940, Phase measurements in electrical prospecting : Am. Inst. Mining Metall. Engineers Trans., v. 

138, p. 456-472. 

Keller, G. V., and Frischknecht, F. C., 1960, Electrical resistivity 

studies on the Athabasca Glacier, Alberta, Canada: Natl. 

Bur. Standards Jour. Research, v. 64D, no. 5, p. 439-448. 

Wait, J. R., 1953, The fields of a line source of current over 

a stratified conductor : Appl. Sci. Research, sec. B, v. 3, 

p. 279-292. 

--1955, Mutual electromagnetic coupling of loops over 

a homogeneous ground: Geophysics, v. 20, no. 3, p. 630-637. 
D-262 GEOLOGICAL SURVEY RESEARCH 1 9.61 

386. GEOPHYSICAL EXPLORATION OF WELLS AS AN AID IN LOCATION OF SALT-WATER LEAKAGE, 

ALAMEDA PLAIN, CALIFORNIA 

By R. P. MosTON and A. I. JoHNSON, Denver, Colo. 

Work done in cooperation with California Department of Water Resources 

In the heavily irrigated Alameda Plain, at the southeastern edge of San Francisco Bay, Calif., there is a 

very high density of wells, many of which have been 

abandoned because of salt-water contamination. It 

seemed probable that saline water from an upper 

aquifer was contaminating the deeper and heavilypumped aquifer by moving downward through a relatively impervious clay layer along defective casings of 

abandoned wells. Geophysical exploration of selected 

:wells in the area was made to determine if such leakage 

did occur. 

Most wells in the area were constructed with a double 

casing, the outer pipe extending from the surface down 

into the clay layer. The annular space between the 

inner and outer casing was filled with concrete and 

served as a seal to prevent leakage of saline water down-

·ward from the upper aquifer. The inner casing extended into the deeper aquifer and was perforated only 

in this aquifer-approximately 200 feet below land 

surface. 

Gamma radiation, temperature, fluid-resistance, and 

self-potential logs were made in five experimental wells 

near Centerville, Calif. The subsurface geology at the 

well sites and the construction features of these wells 

were known in detail and this information served as 

control for interpretation of the logs. Logging was 

later extended to wells in which the geology and construction were known in much less detail. 

Logs were made under pumping, recharging, and 

static con,ditions. A portable submersible pump was 

used to pump the wells at rates up to a maximum of 100 

gpm (gallons per minute), and a 450-gallon water-tank 

trailer was used to recharge wells with 'Yater of known 

quality and temperature. The geophysical logs, a 

driller's lithologic log, and a well-construction log were 

plotted together to assist in the interpretation of conditions in each well (fig. 386.1). 

Lo~s of gamma radiation were used to determine 

lithology and well construction. These logs are especially useful in cased wells, in which electric logs cannot 

be obtained.' The double, concrete-filled casing in the 

upper part of the well shields the gamma radiation of 

the formation, and the depth at which this double casing 

was set could be determined with rea·sonable accuracy 

(fig. 386), depth 200 feet). 

Temperature logging was done in all wells to permit 

conversion of fluid-resistance measurements to conductivity. The temperature log was also used to detect the 

positions of the leaks in the casing or flow of water from 

the upper aquifer to the lower aquifer. vVells outside 

the area of highest saline contamination in the lower 

aquifer had the expected geothermal gradient-the 

water temperature increasing 1° to 2°F per 100 feet of 

depth. In the area of highest saline contamination the 

water temperature of some wells did not follow the expected gradient bttt remained constant or even decreased 

slightly with depth. Heat exchanges caused by interformational flow of water could cause these unexpected 

temperature gradients. 

Changes of water salinity with depth in the well were 

determined by fluid-resistance logging. In wells that 

had not been pumped for months or years, salinity increased with depth in most wells, but decreased with 

depth in others. Possible interforma.tional flow of water within the casing may have kept the lower parts of 

some wells flushed of saline water. The pumping 

equipment did not have sufficient capacity to produce 

significant changes ·in fluid resistance under prolonged 

pumping conditions. 

To test the well casing for leaks by which saline water 

could move from the upper to the lower aquifer, several 

wells were recharged with water of known quality, and 

the wells were then logged several times to determine 

changes in fluid resistance. Figure 386.3 presents a 

series of fluid-resistance logs for a well where a leak was 

suspected by the driller. In this well, water of higher 

resistance than the recharge water 'Yas leaking from the 

aquifer into the well at a depth of 113 feet. 

Self-potential logs help locate perforations and leaks 

in the well casings. Electrofiltration potentials in the 

well bore vary with the rate at which water is being 

pumped from the well, increasing with increasing flow 

through the well face. Thus, zones of leakage might be 

found by comparing self-potential logs obtained under · 

static conditions 'vith those obtained under pumping 

conditions. As the rate of pumping increases, the con-
I. 

~-

SHORT PAPERS IN THE GEOLOGI·C AND HYDRO~OGIC SCIENCES, ARTICLES 293-435 

Gamma radiation log 

Radiation increases 

~ 

~ 

It 

) 

1/ 

11 

? 

\ 

~ 

( 

-f::> { 

~~ 

~ l> 

1 

l'f~ 

I~ 

~\. 

jr> 

_( 

~ 

? 

~ ~~ r'~ 

~ ~ 

(illf]]] 

Top soil 

~ 

:.r.·.-.. z·:-:-

Gravel 

Fl 

I 00 

2 00 

3 00 

4 00 

500 

~ 

~ 8 

.1!:' :§ 

""5! 

"' u 

8 

I 

I 

:go 

ol 

~· c;• 

'I:: I 

~· I 

I 

EXPLANATION 

UIT]· ~ 0 

. . Sand Gravel 

and clay 

- B 

Clay 

~ Sand 

and clay 

Fluid Temperature· 

resistance 

-.-

-r--

~esistance -r--

I~S 

~-

- 2 r- ohm-m 60r-~4 

r-,_:_ 

r--

r--

r-1-

\ t-- \ -

1\ r-- \ ~-

\ 

-r--

-I-

-I1-1-

1-1-

-=:: 

1---'-

c::::::: I--

I- 1-

..__ ~ 

I-- I-

~---~ 

--

--

~ . . ~and with 

cay lenses 

·~·~ 

~~~~ Sand, 

gravel and clay 

Self-potentiallog 

DEPTH, 

Static Pumping IN FE~T 

0 

- 200 mr f--

..L 

\ 1 II 00 

I 

\ 

) 

( 

J 

) 

( 

j 

? ~ v 

b ~ 

~ ~ ~ ~ ·~ =- 300 

..- ~ 

;;;:::> :::> 

:::.-~ -c:: 

r--:;: t---:: F-

~ ~ c~ ~ 

5 .1. 

I 

r( { 

( 1 ~ 

) 

) ) 

lS { 

(/) 

c: 

0 

:;::; I ~, 

~· Q.)f 

0... 

D-263 

Wl 

l!'mumc 386.1.-Constructlon nnd geop~ysical logs from a well FIGURE 386.2.-Self-potentiallogs of a cased well near Alvarado, 

near Alvarndo, Calif. Calif. 
D-264 GEOLOGICAL SURVEY RESEARCH 1 9 61 

80 

100 

120 

..... 

~ 140 

~ 

u.i 

u 

~ 

gs 160 en 

0 

z 

::s 

'::: 

g 180 w 

CD 

J: 

ti: 

w 

0 

-~ Water sample 

1330 ppm chloride 

I I 

I I 

Water sample 

1240 ppm chloride 

, 

I 

l 

~ 

It 

\ c 

J T I 

r- Water sample 

\.170 ppm chloride 

~ 

) "" t---..... 

) 

Wote' 90 ppm "mple chloride . t 

J 

v 

B l! " ' 

~ ~ I 200 

220 

~ 

~ ~~ 

240 ~ ...._ '-- / .......... 

~ ' r Water sample 

I -._ 140 ppm chloride 

RESISTIVITY INCREASES 2 OHM-METERS PER DIVISION -

FIGURE 386.3.-Logs of fluid resistance in a well near Union City, Calif. Log A, static; log B, 20 minutes after 500 

gallons containing 2,000 ppm (parts per million) of dissolved solids was recharged into the well; log C, 60 minutes 

after recharge. 

trast between the potential logs in the producing and 

nonproducing zones increases. This technique was described by Meyer ( 1958, p. 97-98) for an uncased hole. 

It was tried in a newly cased well perforated in two 

zones. A large increase in potential difference was 

noted at the lower perforated zone, but the increase 

opposite the upper zone was insignificant (fig. 386.2). 

If a pump of greater capacity had been available, this 

technique possibly would have provided data of greater 

sensitivity. 

The in-hole logging methods outlined aided in successfully identifying a source of salt-water intrusion 

into deeper aquifers. 

REFERENCE 

:Meyer, Gerald, 1958, The ground-water resources, in Meyer. 

Gerald, and Beall, R. M., The water resources of Carroll 

and Frederick Counties: Maryland Dept. Geology, Mines, 

and Water Resources, Bull. 22, p. 1-228. 
'· 

SHORT PAPERS IN THE GEOLOGfoC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-265 

387. AEROMAGNETIC INTERPRETATION OF ZONED INTRUSIONS IN NORTHERN MAINE 

By JOHN W. ALLINGHAM, Washington, D.C. 

Recent aeromagnetic surveys at two localities in 

northern Maine reveal several distinctive circular 

anomalies associated with granitic intrusions. The 

anomalies are believed to indicate mttgnetically zoned 

plutons. Three-dimensional analyses of aeromagnetic 

data, give the relative width of the magnetic zones and 

indicnte the approximate attitude of their contacts. 

Near tTackman, in northwestern :Maine, a small 

rounded pluton of quartz monzonite and a rim of 

metnmorphic rock create a circular magnetic high over 

'Vood Pond (fig. 387.1). The qmutz monzonite intrudes relatively nonmagnetic lower Pttleozoic sedimentary rocks, mainly sla.te and conglomerate, and 

older, pre-Silurian quartz monzonite (A. L. Albee 

fl.nd Eugene Boudette, written communication, 1961). 

Magnetic hornfels may comprise part of the outer 

zone on the west side of the intrusive. Part of 

the area is covet·ed by water and glacial debris, which 

0 

Aeromagnetic coverage by U. S. Geological 

Survey and Aero Service Corporation 

2 

CONTOUR INTERVAL 50 GAMMAS 

FLOWN AT 500 FEET ABOVE GROUND 

4 5 MILES 

FIGURE 387.1-Total-intensity aeromagnetic map of the Wood 

l.'ond lll'en, :\'fnine. Magnetic profile A-A.' .shown on figure 

H87.o. Quurtz monzonite, shaded pattern; contact, solid where 

based on outcrops, dashed where inferred from aeromagnetic 

datn; outline of cylindricnl model, heavy dashed line. 

604493 0-61--18 

obscure the contact between quartz monzonite and the 

older rocks. 1\-fagnetic zoning is shown by a magnetic 

low that occurs within the area of anomalously high 

magnetism produced by the quartz monzonite pluton. 

The anomaly is elongated southwestward, which indicates a southwestward dip of the intrusive. 

Lower Paleozoic slate and volcanic rocks are intruded 

by a circular pluton of granitic rock at Chandlm~ Lake 

(T. 9 N., R. 8 E.) in northeastern ~{aine (Boucot and 

others, 1960). Thi$ intrusive, which is partly rimmed 

by hills of hornfels, is also magnetically zoned (fig. 

387.2). 

The magnetically zoned intrusions have been analyzed by comparing them to a model of concentric cylinders (figs. 387.3 and 387.4) for ·which magnetic 

profiles (A-A')were computed by use of three-dimensional polar charts of I-Ienderson (1960). Cylinders 

were selected because of the circular symmetry of the 

observed _magnetic anomalies. Compensation was made 

for the regional northwesterly geomagnetic gradient. 

0 2 

CONTOUR INTERVAL 50 GAMMAS 

FLOWN AT 500 FEET ABOVE GROUND 

FIGURE 387.2-Total-intensity aeromagnetic map of the Chandler Lake nrea, :l\iaine. ·:l\iagnetic profile A-A' shown on figui·e 387.4. Granitic intrusive, shaded pattern; contact solid 

where based on outcrops, dashed where inferred from aeromagnetic data; outline of cylindrical model, heavy dashed line. 
D--:266 GEOLOGICAL SURVEY RESEARCH 1 9 61 

2000'j A 

Sea level 

-2000' 

7 

I 

I 

~Computed 

/ 

/ / 

+ + + 

EXPLANATION 

Younger quartz 

~ monzonite 

· Seeboomook ~ formation 

Older quartz ~ monzonite 

0 • !MILE ......__.....__.~--__ __j 

FIGURE 387.3.-Magnetic zoning in the younger quartz monzonite 

intrusive at Wood Pond, Maine. 

Total-intensity profiles were computed in the direction 

of the earth's magnetic field. The remanent magnetization is less than the induced magnetization and is 

assumed to be negligible. Cylinders giving the best 

fit with the observed data are assumed to approximate 

the zoned plutons. The computed magnetic susceptibility of the outer zone of the quartz monzonite at Wood 

Pond, K = 1.1 X 10-3 cgs units, compares favorably with 

the measured susceptibility, which is 1.0 X 10~3 cgs units 

(average of 3 san1ples). For the purpose of the analysis, the susceptibility of the hornfels (less than 

0.1 X 10-3 cgs units) is negligible. To match the observed profile over the Chandler Lake intrusion, two 

susceptibilites are needed for the outer zone. The 

southeast part must have a susceptibility of 2.1 X 10-3 

cgs units and the northwest part 2.6 X 10-3 cgs units. 

The fit of the observed and theoretical curves (figs. 

387.3 and 387.4) indicate that the contacts of the plutons 

with the country rock are nearly vertical, except for 

the south contact of the quartz monzonite at Wood 

Pond which dips less steeply. The absence of small 

Inclination of the 

3300 earth's field 

\ 3100 

If) 

c( 

:::E 

:::E 

c( 

CJ 

2900 

2700 

0 2 MILES 

FIGURE 387.4.-Magnetic zoning in the granitic intrusive at 

Chandler Pond, Maine. 

sharp isolated anomalies over the contact \ones shows 

that magnetite, which largely determines the magnetic 

susceptibility, is evenly distributed in these contact 

zones.. The magnetic patterns over the plutons resemble those observed elsewhere over ring dikes. 

REFERENCES 

Boucot, A. F., Griscom, Andrew, Allingham, J. W., and Dempsey, 

W. J., 1960, Geologic and aeromagnetic map of northern 

:Maine: U.S. Geol. Survey open-file report. 

Henderson, R. G., 1960, Polar charts for evaluating magnetic 

anomalie~· of three-dimensional bodies, in Short papers in 

geological sciences: U.S. Geol. Survey Prof. Pa.per 400-B, 

p. B112-Bl14. 
I, 

SHORT PAPERS IN THE GEOLOGI!C AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-267 

388. AEROMAGNETIC, AERORADIOACTIVITY, AND GRAVITY INVESTIGATIONS OF PIEDMONT ROCKS IN THE 

ROCKVILLE QUADRANGLE, MARYLAND 

By ANDREW GmscoM and DoNALD L. PETERSON, Washington, D.C. 

A combined aeromagnetic and aeroradioactivity survey .in the Uockv.ille aren, l\1nry land, was made during 

1H58 by t-he U.S. Geological Survey as part of a geophy~.ical study of the l\1aryland Piedmont. The aeromagnetic data were obtained and compiled by procedures previously described (Balsley, 1952). The scintillation detection equipment has been described by 

Davis and Reinhardt (1957) n.nd the record is compen-

~a.ted for v~triations in flight elevation. The radiation 

components produced by cosmic radiation and radionuclides in the air lut\re been removed prior to contouring by nssigning n level of zero to dabt obtained over 

wide stretches of the Potomac River. East-west traverses' were fiown ~tt n, spacing of one-quarter of a mile 

and a flight elevation of 500 feet. Four north-south tie 

lines were flown to tie the traverses together. A grnvity survey of the Rockville quadrangle was made in 

1960. 

The bed rock consists of the 'Vissahickon formation 

intruded by large bodies of gabbro and serpentinized 

periodotite. The vVissahickon formation is composed 

mainly of schists which resulted from the metamorphism of former shales and siltstones to quartz-albite· 

rnuscovite-chlor:ite-magnetite assemblages. Locally 

there are higher grade mineral assembhtges containing 

biotite an'd garnet. The serpentines contain considerable primn,ry mn,gnetite and ~tlso secondary magnetite 

fot·med during serpentinization of the preexisting 

peridotite. In general, the gabbro contains less magnetite thtt.n the "Tissahickon formation. The 1nargins 

of the gabbro are metamorphosed to the green-schist 

facies a.nd ~tppettr to contain mor.e magnetite than the 

less-altered cent raJ portions. Geologic contacts (fig. 

388.1) were determined from ground reGonnaissance 

w:ith the aid of aeroradioa.ctivity and soils maps. 

The aeromn,gnetic map (fig. 388.1) shows a linenr 

magnetic grain associated with the structural trend of 

the folded "Tissa,hickon formation. This pattern indi· 

c~ttes that vnrious subunits have differing magnetizntions. Some of these subunits can be traced on the 

ground. The largest magnetic highs are located over 

serpentine. The relations between highs and ~tssociated 

low~ show that at lettst locally within the larger serpentine body there must be :t renutnent magneUzation in 

a direction different from that of the earth's field. 

Other nearby serpentine dikes (not in this quadrangle) 

produce negative anomalies which are probably caused 

by strong inverse remanent magnetizations. The gabbro bodies in general are characterized by magnetic 

lows which are rimmed by magnetic highs that are 

associated with the contacts (fig. 388.1). These marginal highs are probably associated with the metamorphosed borders of the gabbro. A two-dimensional 

magnetic computation was made across the central gabbro body nlong section A-A', using the configuration 

deduced from the gravity data. A reasonable fit with 

the observed data was obtained (fig. H88.2) by using 

a susceptibility contrast of 0.0014 cgs unit for the central mass and 0.0033 cgs unit for the lower density 

metamorphosed nutterial along the contacts. 

The contoured aeroradioactivity data are shown on 

figure 388.3 ( p. D-270). The radiation recorded at 

500 feet elevation is virtually the average value of radiation from within a circle 1,000 feet in diameter on the 

ground. The bulk of t-he measured radiation comes 

from the uranium and thorium radioactive decay series 

and from pohtssium-40. These elements tend to occur 

together and are relatively abundant in shales and 

granitic rocks but are relatively scarce in mafic and 

ultramafic rocks. On figure 388.3 the mafic intrusions 

are outlined by the radiation lows and the contacts can 

be located with considerable accuracy. Linear radiation trends produced by the 'Vissahickon formation 

correspond with aeromagnetic trends and the two maps 

have proved most useful when used in conjunction. 

The simple Bouguer values shown on the gravity 

map (fi. 388.4, p. D-271) are all positive and range 

from about +37 to a:bout +51 milligals. The measurements outline a large positive closure of + 14 milligals elongated northeast, parallel to the trend of the 

aeromagnetic and aeroradioactivity anomalies. I...JOcal 

highs coincide with the gabbro outcrops showing that 

the anomaly is caused by h~gh-density gabbro in contrast with lower density schist. 

Theoretica,l gravity values were computed for a 

hypothetical gabbro body along section A-A'. The 

body was assmned to be two-dimensional. The sharp 

peak of the measured profile could not be matched 

using a simple density contrast so that the body was 

separated into a high-den.sity core with a lower density 

border zone. The best match was obtn.ined using a 

core density contrast of 0.23 g per em 3 , a border zone 
D-268 

7JC15'00" 

GEOLOGICAL SURVEY RESEARCH 1 9 61 

Serpentine 

-

0 

Wissahickon formation 

.,.-20ooAeromagnetic contour 

"'' u 

0 

N 

0 

L!J 

...J 

c( 

a.. 

0: 

L!J 

S; 

0 

...J 

_Ll:"---">.=:::c__..L.f_,t~_-'l.::LL..Lf_----l.~~~...\....l..ClLL-L/.'_L.LLL_J_ ____________ _.J 39°00'00" 

0 1 MILE 7]007'30" 

FIGURE 388.1.-Aeromagnetic and generalized geologic map of the Rockville quadrangie, Maryland. Contour interval 50 

and 250 gammas. Datum: arbitrary. 
"'t' 

SHORT PAPERS IN THE GEOLOG~C AND HYDROLOGIC SCIENOES, ARTICLES 293-435 D-269 

A 

600-

I I 

I 

I 

I 

I 

I 

I 

Aeromagnetic profile 

(arbitrary datum) 

I Simrle Bouguer gravity profile 

I 

I 

Computed o 

0 

Wissahickon formation 

0 

0 

~// + "~~ ;y/+ + + + + '-~~~ 

I I 0 ~ I 

I 1 

I + \ 

Gabbro 

s::::-)( /f' + '- '-,)( /-')' / + +Gabb+ro + + +"~~..,~~ 

L~ ~ + Bottom of density contrast + + + " 

1 ~ 0 

0 

\ I + \ 

Gabbro 

2 MILES 

A' 

0 0 

Wissahickon formation 

Jj""wu•u~ 388.2.-Aeroradioactivity, aeromagnetic, simple Bouguer gravity, and geologic profiles along section A-A'. The 

circles represent computed aeromagnetic and gravity points using the assumed shape of the gabbro body. 

density contrast of 0.1 g per em S, and the configuration 

shown on figure 388.2. Although the densities and 

their proportions could be changed somewhat, it seems 

clear tlmt the body is more dense toward the center, has 

n. shn.pe similar to that which is shown, a.nd extends at 

least several thousand feet in depth. Estimated residual n.nomalies of + 6 milligals and + 3 milligals are 

n.ssoc.ia.ted with the gabbro outcrops on the southeast 

side of the. section. The high regional gravity level 

( + 37 milligals) indicates that there is a much larger 

mass of dense rock below the gabbro body. 

REFERENCES 

Balsley, J. R., 1952, Aeromagnetic surveying, in Landsberg,_ 

H. E., ed., Advances in geophysics: New York, Academic 

Press, Inc., v. 1, p. 313-349. 

Davis, F. J., and Reinhardt, P. ·w., 1957, Instrumentation in 

aircraft for radiation measurements: Nuclear Sci. and 

Eng., v. 2, no. 6, p .. 713-727. 
D-270 GEOLOGICAL SURVEY RESEARCH 1 9 61 

wf 

1 0 1 MILE 

Dl 

Serpentine 

77°07'30" 

39°07'30" 

.... 

u 

0 

N 

0 

LLI 

...J 

c( 

D.. 

0:: 

LLI 

~ ~ Wissahickon formation ...J 

_soo __ 

Radioactivity contour 

FIGURE 388.3.-Aeroradioactivity and generalized geologic map of the Rockville quadrangle, Maryland. Contour interval. 

50 co~nts per second. · 
SHORT PAPERS IN 1'HE GEOLOG~C AND HYDROLOGIC SCIENCES, ARTICLES 293-435 

wf 

0 

• 

I wf I 

I 

I 

\ 

\ 

' 

------

EXPLANATION 

--+40--

Simple Bouguer gravity contour 

• Gravity station 

Rockville ~ quadrangle location 

~ Gabbro 

Serpentine 

~ 

0 

Wissahickon formation 

2 MILES 

• 

..... 

u 

0 

N 

0 

w 

..J 

<( 

a.. 

0:: 

w 

3: 

0 

..J 

D-271 

• 

• 

• 

• 

FIGURE 388.4.-Simple Bouguer gravity and generalized geologic map of the Rockville quadrangle, Maryland. Contour 

interval one milligal. 
D-272 GEOLOGICAL SURVEY RESEARCH 1 9 61 

389. ELECTRICAL PROPERTIES OF A PART OF THE PORTAGE LAKE LAVA SERIES, 

HOUGHTON COUNTY, MICHIGAN 

By G. V. KELLER, Denver, Colo. 

The electrical properties of rocks in the Michigan 

copper district along the south shore of Lake Superior 

are being investigated to determine which of several 

electrical prospecting methods might be useful in the 

search for additional ore. Two methods of investigations are being used : measurement of the electrical 

properties of the rock in place using bore-hole logging, 

and laboratory measurement of electrical properties and 

determination of rock textures of drill-core samples. 

In 1958 and 1959, the Calumet and Hecla Consolidated Copper Co. drilled a series of prospect holes along 

the strike of the Iroquois amygdaloid· of the Portage 

Lake lava series of l{eweenawan age near Calumet, 

Mich. These regularly spaced drill holes provided an 

opportunity to study the continuity of electrical properties along the strike of the beds. The continuity in 

electrical properties is one of the most important factors 

in determining whether electrical surveys can be used 

successfully in mapping geologic structure. 

Three properties were determined in this evaluation 

of electrical prospecting methods: the electrical conductivity of the rock, the capacity for induced electric 

polarization, and the magnetic susceptibility. Borehole measurements of each of these properties were 

made, and measurements of the vertical component of 

the magnetic field and the spontaneous potential were 

also obtained. The logs were run in 10 drill holes along 

a line extending northeast through the town of Calumet. The spacing between these holes was approximately 1,000 feet. 

A cross section comparing conductivity and magnetic 

susceptibility logs from five of these drill holes is shown 

on figure 389.1. The conductivity logs were run with a 

conventional g"uard electrode system. The magnetic 

susceptibility was measured with an induction coil operated at 400 cps,. with a measuring field intensity of 

about 0.2 oersted. 

Tlu~ rock penetrated by these five holes is the Iroquois 

amygdaloid of the Portage Lake series. The Iroquois 

consists of three flows, with three oxidized amygdaloidal units, designated A, B, and C. The electric logs 

are alined using the base of the Iroquois amygdaloid B 

as a datum plane. The logs on figure 389.1 do not 

extend into amygdaloid C. 

The amygdaloidal units are more conductive than the 

rest of the flows. The conductive zones generally 

extend several feet above and below the zones geologically described as oxidized amygdaloids, indicating 

that only the center parts of the porous amygdaloida1 

units have been oxidized. The conductive beds appear 

to· be continuous from hole to hole, though the thickness 

of the conductive amygdaloidal units varies considerably. The electrical properties of the traprock between 

the amygdaloidal units also vary from hole to hole. 

Average resistivities of the· traprock and of the 

. amygdaloidal units in three of the' drill holes were computed by averaging the resistivity values appearing on 

the logs at 2-foot intervals. The results are 'listed in 

table 889.1. The resistivity of the traprock is approximately twiee that. of the amygdaloids. Both the trap 

TABLE 389.1.-Average electrical properties, taken from electric logs 

I 

Transverse I Longitudinal I resistivity resistivity (ohm-meters) (ohm-meters) 

Drill hole Centennial DH-9 

Traprock ________________ _ 

Amygdaloid units ________ _ 

279 

136 

Drill hole Centennial DH-12 

Traprock ________________ _ 

Amygdaloid units_________ ,. 

498 

296 

Drill hole C & H DH-22 

Traprock ________________ _ 

Amygdaloid units ________ _ 

596 

273 

236 

108 

420 

244 

520 

248 

Coefficient 

of macroanisotropy 

1. 09 

1. 12 

1. 09 

1.10 

1. 07 

1. 05 

and the amygdaloids have moderately low coefficients 

of macroanistropy, which range from 1.05 to 1.12. 

The magnetic susceptibility of the amygdaloidalunits 

is uniformly low, generally less than 2 X 10-6 cgs units. 

The magnetic susceptibility of the traprock is considerably higher, ranging from 5 X 10-4 to 4 X 10-3 cgs 

units. The zones of high susceptibility cannot be traced 

from hole to hole, however, and probably are local 

concentrations of magnetite. 

The induced polarization measurements were made 

inhole using a repeating pulse method. No logs are 

shown, as a relatively uniform response of from 0.75 to 

1.50 percent was recorded in all drill holes. There was 
~ 

Drill hole C and H 28 Drill hole C and H 26 Drill hole C and H 22 Drill hole Centennial 12 Drill hole Centennial 9 

UECTRirAL 

CONDUCTIVITY 

IN MHO/METER 

DEPTH, :G 5! 

IN FEET 8 8 oc c) ci 

a 

"' 1§ 

"0 

·a 

~ e < 

T 

J~ ·a 

ftj <"g. 

e 

l< 

a 

"' .= 

l~ "0 

·a 

ftj II) "g. 

e < 

I a 

"' .= § 

MAGNETIC 

SUSCEPTIBILITY 

IN CGS UNITS 

"' "' ~ "' 8 8 8 8 d 0 c) 0 c::) 

UECTRI('AL MAGNETIC --

CONDUCTIVITY SUSC£PTIBILITY 

IN MHO/METER IN CGS UNITS 

"' 5! "' "' ~ "' 8 8 8 8 8 8 

UECTRirAL 

CONDUCTIVITY 

IN MHO/METER 

MAGNETIC 

SUSC£PTIBILITY 

IN CGS UNITS 

"' 5! .., .., !il "' 8 8 8 8 8 8 00 0 ci c::i 0 0 ci ci 00 0 c::i ci 0 c:i ci d 

a 

~ I I I II I I I i 

J 

~~§ ~lillllU' I§ 

! . T l 1 0 

~~ . <t~ 1! c~ r . a g "' .= .= 

11)"0 

J. ·a 

ftj 1 ftj 

.. 11)"0 

e 

r~ r~ a 

"' a 

.= "' 

I .= 

C::::l I I I § 

ELECTRirAL MAGNETIC ELECTRICAl 

CONDUCTIVITY SUSC£PTIBILITY CONDUCTIVITY 

IN MHO/METER IN CGS UNITS IN MHO/METER 

"' 5! "' "' ~ "' "' § 8 8 8 8 8 8 8 00 0 0 00 0 0 0 00 0 0 

"0 

·a 

ftj 

-g. 

e 

< 

"0 

T8 ·a 

~ e 

< 8 T- g - .= 

1 g 

.= 

l~ Jl ftj 

1) ~ a· 

"' .= 

.= 

g 1~ 

l~ "0 

·a 

ftj 

11)-g, 

ftj e 

r~ c: 

a 

I~ a 

"' "' . .= .::: 

FIGURE 389.1.-Comparison of electric logs from a series of bore holes penetrating the Iroquois amygdaloids A and B near 

Calumet, :Michigan. 

MAGNETIC 

SUSC£PTIBIUTY 

IN CGS UNITS 

"' "' 8 8 00 0 

!il 

8 

0 

Ul 

p:: 

0 

~ 

t-3 

'"d 

> '"d 

l"J 

~ 

Ul 

~ 

z 

~ l"J 

0 

l"J 

0 

t"-4 

0 

0 

~ 

0 

~ ~ 

~ 

~ 

~ 

~ 

0 

t"-4 

0 

0 

~ 

0 

l[2 

0 

~ 

l"J 

~ 0 

l"J 

sn 

> 

~ 

j 

0 

t1 

l"J 

U1 

t:-:1 

co 

~ 

I 

~ 

~ 

t1t 

'I 

~ ~ 
D-274 GEOLOGICAL SURVEY RESEARCH 19 61 

no observable difference in induced polarization of the 

traps a1id the amygdaloids. 

Samples were taken at 5-foot intervals from drill 

hole C & H DH-22 for laboratory measurements of 

electrical properties. These samples were resaturated 

with water, and the resistivity and induced polarization response were measured. These data (table 389.2) 

show that the traprock has a slightly higher polarization response, on the average, than does the amygdaloid. 

This difference may be caused by a greater amount of 

magnetite in the trap.· 

The amygdaloid samples are about ten times as porous 

as the trap samples. With such a contrast in porosity, 

it would be reasonable to expect a larger contrast in 

resistivity between these two rock types than was observed in the bore-hole measurements. The resistivity 

of the amygdaloids in place may. be anomalously high 

either be cause they are not completely water saturated, 

or because they have been flushed by circulating surface 

waters. 

TABLE 389.2.-Summory of induced polarization measurements 

determined in the laboratory 

[All samples from drill hole C & H DH-22] 

Group of samples Number of Porosity I. P. response samples (percent) (percent) 

Upper amygdaloid _________ 3 4. 90 1. 73 

Traprock _________________ 13 0. 87 2. 06 

A amygdaloid _____________ 3 5. 11 1. 10 

Traprock _________________ 3 0. 87 1. 95 

B amygdaloid _____________ 7 8. 88 1. 63 

Traprock _________________ 11 0. 75 2. 20 

C amygdaloid _____________ 3 7. 07 1. 90 

ACKNOWLEDGMENTS 

I wish to express my thanks to the Calumet and Hecla 

Consolidated Copper Co. and, in particular, to Dr. 

James P. Pollack, Chief Geologist, for permission to 

conduct this study. 

390. GRAVITY ANOMALIES, ISOSTASY, AND GEOLOGIC STRUCTURE IN CLARK COUNTY, NEVADA 

By MARTIN F. KANE and J. E. CARLSON, Washington, D.C., and Menlo Park, Calif. 

In 1957, a gravity survey of Clark County, Nev. 

was started to investigate the relation of the gravity 

field to geologic structures. Gravity stations were set 

in the mountain areas, as well as in valleys, in order to 

study variations in gravity over bedrock However, 

the high cost of obtaining completely representative 

bedrock measurements in the dry, rugged ranges of · 

Clark County restricted the survey to roads and paths 

of easy access where most points of known altitude are 

shown on topographic maps. Despite this limitation, 

the overall gravity measurements have revealed a pattern of anomalies that indicates a close relationship 

between isostatic adjustment and geologic structures. 

Mabey ( 1960) has shown that over much of the Basin 

and Range Province regional topography and Bouguer 

gravity anomalies are inverse~y related. This correlation implies that a given mass of terrain is compensated 

by a mass deficiency below and near the area. One can 

examine this same condition by a study of· the freeair gravity anomaly (fig. 390.1). If the average free-

,air anomaly is near zero for a large area, it indicates 

(as does Mabey's correlation of negative Bouguer 

anomalies with elevated topography) that the terrain 

of the area is generally compensated. 

Measured free-air anomalies in Clark County range 

from + 132 mgal to -111 mgal and average -15 mgal. 

Figure 390.1 shows that the negative anomalies are over 

low-altitude alluviated areas and that positive 

anomalies are restricted to higher altitude bedrock 

areas; the distribution of stations shows that the negative anomalies are reasonably well defined. However, 

free-air anomalies are sensitive to the average altitude 

of a given area, and gravity stations should be distributed in a pattern representative with regard to elevation. In Clark County, bedrock stations are located 

in accessible areas, and they are generally below the 

average height of the bedrock mass. Moreover, some 

stations are restricted to alh1viated areas between bedrock masses (mainly in the western part of the northern 

ranges), thereby putting all negative values in areas 

that should also show positive values. Adjustments for 

these discrepancies are both in a positive sense so that 

an adjusted average value would be closer to zero. 

Therefore, isostatic compensation within the county as 

a whole seems nearly complete. 

The free-air-anomaly map (fig. 390.1) consists of a 

regular series of positive and negative anomalies which 

can be related to distinct geologic features. The am-
0 

SHORT PAPERS IN THE GEOLOGI·C AND HYDROLOGIC SCIENCES, ARTICLES 293-435 

0 10 20MILES 

Cenozoic sedimentary rocks 

Pre-Cenozoic sedimentary bedrock 

Crystalline bedrock 

0 

Gravity station 

--40--

Contour, showing free-air 

gravity in milligals 

Hachures indicate areas of 

negative closure 

Contour interval 20 milligals 

Geology generalized from 

Bowyer and others, 1958 

FIGURE 390.1.-Free-air gravity contours and generalized geologic map of Clark. County, Nev. 

D-275 
D-276 GEOLOGICAL SURVEY RESEARCH 19 61 

plitudes in positve areas are closely propor.tonal to altitude, and the zero isogal is generally near the 4,000-

foot contour. Anomalies are positive on the Paleozoic 

rocks of the northern ranges and the Spring Mountains, and the zero isognls are near the bedrock-alluvium 

contacts. The positive-anon~aly areas include the 

Paleozoic mountain blocks and show that locally they 

are an excess crustal load. The average anomaly is 

closer to zero on the Precambrian rocks of the Virgin, 

Lucy Crey-McCullough, and El Dorado-Newberry 

Ranges. The coverage over Precambrian bedrock is incomplete, but the Precambrian blocks appear to· be close 

to isostatic balance ''"ithin the motn1tain boundaries. 

....-\..11 of the high negative anomalies are over alluviated 

basins, which therefore are areas of local deficient load. 

In summary, the general pattern of anomalies shows 

positive values on Paleozic bedrock (excess load), negative values on alluviated basins (deficient loads), and 

near zero values on Precambrian bedrock (balanced 

loads). 

If the Precambrian areas are excluded, it is apparent 

immediately that the average zero free-air anomaly for 

the entire area is dependent on the opposing free-air 

anomalies of the Paleozoic mountain blocks and the alluvinted basins. Furtlwr, the mountain areas and basin 

areas are in juxtaposition, which suggests that they act 

as pairs. It is difficult to imagine an isostatic mechanism that permits separated mountain and basin blocks 

to balance one another; however, it seems reasonable to 

conclude that the basin is the depressed end and the 

SPRING MOUNTAINS A' 

15,000l A z 

Q~ § ~10,000 

~~ L&J 

5000 

~ -100l grav~ _ - - - - - - - _ (.!) .,uer __ 

::::i -120 ~\)~- . ...J - :E .,.,. ...... ..,..,.----

-140 

range is the uplifted end of one tilted mountain block. 

Thus, the Spring Mountains represent the uplifted end 

and Las Vegas Valley the depressed end of a single 

block; the northern ranges and the Morman Mesa area 

are paired similarly. A cursory inspection suggests that 

each block is in isostatic adjustment, but this cannot be 

clearly determined owing to the limits of data noted 

above and to the unknmvn physical limits of the block. 

CAUSE OF TILTING 

The Bouguer gravity (fig. 390.2) is relatively low 

over the highest parts of the Spring Mountains and the 

the northern ranges; further, the Bouguer anomalies 

are too large to be attributed to inaccurate reductions 

(mainly terrain corrections), and too small to offset the 

high positive free-air values. The Bouguer values are 

caused by a low-density mass under the high parts of 

the ranges, and they can be correlated with a marked 

increase in thickness of the Paleozoic rocks. The computed mass effect of the Paleozoic section as compared 

to the higher density Precambrian rocks to the east is 

approximately equal to the anomalous Bouguer gravity, 

and it is concluded that the anmnalies are caused by the 

Paleozoic rocks. Analogously, lower Bouguer anomalies are present over the high parts of the Precambrian 

ranges and can be attributed to lower density granitic 

rocks that are present in these areas. The presence of 

low-density masses on the uplifted ends of mountain 

blocks that are probably tilted suggests that these 

masses are buoyant and provide the force necessary to 

8 NORTHERN RANGES B' 

D D' E E' z . EL DORADO MOUNTAINS 

~ 1-5000~ ~ ~ ~ 3000 Topography 

u1 1000 

z DEAD MOUNTAINS 

Q~ 4000~op 0 ~ ~ 2000 'l!raPhy 

L&JZ u1 -Sea level 

cc ~ -801 "ra'<~. - . '-'t-- § -90 B~~~e!...-"'--

....1 --

~ -100 ' 

...J en -70 j (3 -80 'b..j\~ .... --

::::i Q,~., 

~ ....,go Bouguej.."' ~ ---- -100 

0 5 10 15 20 MILES 

FIGURE· 390.2.-Comparison of simple Bouguer gravity and regional elevations over bedrock areas in Clark County, Nev. 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-277 

tilt the blocks initially. Once tilting has started, sediments accumulating on the depressed end of the block 

serve to increase the tilt. These examples in two dissim.ilar geologic settings (crystalline versus sedimentary 

terrain) indicate that tilting may have a wide application n,s a mechanism of isostatic adjustment. 

The buoyant tilting of segments of the earth's crust 

requires that the segments be outlined by deep crustal 

faults and have relatively free boundaries. Longw·ell 

(1960) suggests that the Las Vegas shear zone which 

separates the Spring Mountains and the northern 

rn.nges is a major crustal rift. The eastern bound·aries 

of the blocks are defined by alluviated basins which 

imply a stratigraphic break in the crust of as much as 

several miles. At present, there is no evidence of the 

remaining boundaries, and they may lie outside the 

county. 

REFERENCES 

Bowyer, Ben, Pampeyan, E. H., and Longwell, C. R., 1958, Geologic map of Clark County, Nevada: U.S. Geol. Survey 

Mineral Inv. Field Studies Map MF-138. 

J.;ongwell, C. R., 1960, Possible explanation of diverse structural patterns in southern Nevada: Am. Jour. Sci., (Bradley 

Volume) v. 258.-A, p. 192--203. 

Mabey, D. R., 1960, Regional gravity survey of Nevada, in short 

papers in the geological sciences: U.S. Geol. Survey Prof. 

Paper 400-B, p. B283-B285. 

391. ISOSTATIC COMPENSATION IN THE SANGRE DE CRISTO MOUNTAINS, NEW MEXICO 

By GoRDON E. ANDREASEN and MARTIN F. l(ANE, Washington, D.C. 

The Sangre de Cristo Mountains consists of a northtrending chain of structurally complex mountains 

bordered on the east by the High Plains and on the 

west by the Rio Grande trough. Baltz and others 

( 1956, p. 15) describe the mountains as a faulted 

asymmetrical synclinorium that plunges southward. 

In general, Paleozoic sedimentary rocks in a relatively 

high region that borders the Rio Grande trough dip 

eastward toward the axis of a syncline that extends 

northeastwnrd from Cowles (fig. 391.1). East of the 

syncline axis the sedimentary rocks rise to a northtrending ridge located a few miles west of a line connecting Las Vegas and Cimarron. Predominantly 

clnstic sedimentary rocks of Pennsylvanian age at least 

8,000 feet thick crop out in the central part of the synclinorium (Read and "T ood, 1947). A variety of 

plutonic and metamorphic rocks of Precambrinn age 

also are present; these include schist, gneiss, and 

quart~ite which, in several places, have been intruded 

by granite of more than one age (Baltz and Bachmnn, 

1956, p. 96). 

Figure 391.1 .is a regional Bouguer anomaly nnd 

geologic map of the southern Sangre de Cristo Mountains. All gra.vity stations were located along accessible roads either at bench marks or at points where 

elevation information was available from the New 

Mexico State Highway Commission. The Bouguer 

gravity anomaly map does not include correction for 

terrain effects. I:Iowever, sample terrain corrections 

computed for critical stations shows that the largest 

effect is a.bout 8 milligals. 

"Vithin the surveyed area, the Bouguer gravity values 

decrease as the mountains are approached from the east, 

and are lowest over the mountain mass. Superimposed 

on the general gravity gradient is a local negative 

anomaly located approximately at the center of the map 

(fig. 391.1). The lqwest gravity occurs over the highest 

topography (fig. 391.2)-an inverse relation that has 

been observed in other areas (l(ane and Carlson, Art. 

390), and is probably caused by a near-surface mass 

deficiency. If the regional gravity gradient has been 

properly chosen, the maximum a.mplitude of the 

anomaly is 21 milligals. A teri·ain correction of ~bout 

5 milliga.ls leaves a residual anomaly of about 16 milligals. If it is assumed that the density contrast between 

the Precambrian rocks and the Pennsylvanian clastic 

rocks is about 0.2 g per cm8 then the anomaly indicates 

a thickness of clastic rocks in excess of 6,000 feet, which 

correlates closely with the known thickness of clastic 

rocks in this area and strongly suggests that they are 

the source of the anomaly. 

In order to demonstrate better the correlation between 

topography and Bouguer gravity, a method suggested 

by l\1ab~y (1960, p. B130) ·was einployed in which the 

topography is averaged over circles 64 miles in diameter 

at each station location. The resulting regionalized 

topographic attd Bouguer anomaly map is shown on 

figure 391.3 (p. D-280). It may be noted that theregionalized topographic contours generally parallel the 

Bouguer isogals. However, there is a notable decrease 

in the rate of change of regional topography with 

Bouguer gravity in the highest part of the mountains. 
D-278 GEOLOGICAL SURVEY RESEARCH 1 9 6 1 

EXPLANATION 

E3 Cenozoic sedimentary rocks 

I· •··••·I Cretaceous to Recent 

·extrusive rocks 

c=J Mesozoic sedimentary rocks 

0 5 10 

Paleozoic 

-

sedimentary rocks 

Precambrian gneiss, 

~ 

~ 

schist,and granite 

• Gravity station --200--

Bouguer anomaly contour; 

5 milligal interval 

20 25 MILES ~----L-----~----~----~----~ 

Geology after Darton, 1928 

FIGURE 391.1.--Regional Bouguer anomaly and geologic map of the Sangre de Cristo Mountains, N. Mex. 

,I 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-279 

-175 

-200 

~ 3 

SE -225 

-250 

X 

I.U 12,000 -

~ al_. 

t~ 10,000 

I.U-' 

~~ 8000 

~~ ~~ 6000 

~ 

/ 

/ 

I 

I 

I / 

4000 -------

0 10 20 MILES 

-----------

EXPLANATIQN 

liJ Cenowic sedimentary rocks 

Do Mesozoic sedimentary rocks 

Paleozoic ~ sedimentary rocks 

Precambrian gneiss, 

f"'77l 

~ 

schist, and granite 

--

X' 

FIGURE 391.2.-Topographic, geologic, and gravity ,,profile across the Sangre de Cristo Mountains. Line of section (X-X') 

and explanation of rock units shown on figure 391.1. 

The mass-deficiency suggested by the large Bouguer 

anomaly (fig. 391.1) can be further analyzed by a freeair anomaly map (fig. 391.4, p. D-281). A positive 

free-air anomaly coincides with the crest of the mountains, and this anomaly shows that the main mountain 

mass is, at least locally, an excess load, and is not supported by the low-density mass outlined by the Bouguer 

gravity anomaly. 

.. A.· Bouguer gravity high at the northwest end of the 

profile (figs. 391.1 and 391.2) is present over Precu,mbrian -rocks along the western margin of the mountains; however, the Precambrian rocks along the eastern margin of the mountains do not have an associated 

gravity high. Either the Precambrian rocks at the 

easte111 margin of the mountains have insufficient volume to produce an anomaly, or crystalline and sedimentary rocks of this area have nearly the same density. 

REFERENCES 

Baltz, E. H., Wanek, A. A., and Read, C. B., 1956, Resume of 

geology-Santa Fe to Cowles; Pecos to Las Vegas, in New 

Mexico Geol. Soc. Guidebook of southeastern Sangre de 

Cristo Mountains, ~ew Mexico, 7th Field C9nf. 1956: 

p. 15-23. 

Baltz, E. H., Jr., and Bachman, G. 0., 1956, Notes on the 

geology of the southeastern Sangre de Cristo Mountains, 

~ew Mexico, i.1t New Mexico Geol. Soc. Guidebook of southeastern Sangre de Cristo Mountains, New Mexico, 7th Field 

Conf. 1956 : p. 96-108. • 

Darton, N. H., 1928, New Mexico State geologic map: U.S. Geol. 

Survey. 

Mabey, D. R., 1960, Regional gravity survey of part of the 

Basin and Range province, in Short papers in the geological 

sciences: U.S. GeoL Survey Prof. Paper 400-B, 

p. B283-B285. 

Read, C. B., and Wood, G. H., Jr., 1947, Distribution and correlation of Pennsylvanian rocks in late Paleozoic sedimentary 

basins of northern New Mexico: Jour. Geology, v. 55, no. 3, 

p. 220-236. 
D-280 

/ 

/ / 

/ / / / / / / / 

,p/ 

,'l' 

• Santa Fe 

rf:P""---

• 

GEOLOGICAL SURVEY RESEARCH 1 9 6 1 

-:270-----

Taos 8 

/ 

/ 

/ 

/ 

&/ / 

.. //<.-

/ / 

• 

I 

• I 

_1/ I/· '\9cp0 I 

/ 

/ / 

/ 

/ / 

/ ......... - / 

/ 

0 5 

----

10 

/ 

I 

I 

I 

I 

I 

I 

I 

/ 

I 

I 

J 

15 20 25 MILES 

• 

EXPLANATION 

---- -210 ----

Bouguer anomaly contour; 

10 milligal interval 

• Gravity station 

---8000---

• 

Regionalized topographic contour; 

· Contour interval 200 feet 

except 8700 contour 

FIGURE 391.3.-Bouguer anomaly and regionalized topographic map of the Sangre de Cristo Mountains, N. Mex. The 

topography is averaged over circles 64 miles in diameter. 
SHORT PAPERS IN THE GEOLOG.IIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 

E3 Cenozoic sedimentary rocks 

c::J Cretaceous to Recent 

·extrusive rocks 

c::J Mesozoic sedimentary rocks 

0 5 10 15 

Paleozoic 

-

sedimentary rocks 

Precambrian gneiss, 

~ 

~ 

schi8t,and granite 

• Gravity station 

----20--

Bouguer anomaly contour; 10 milligal interval 

20 

.E''IGURE 391.4.-Free-air gravity anomaly and geologic map of the Sangre de <?risto Mountains, N. Mex. 

604493 0-11~-61 

D-281 
D-282 GEOLOGICAL SURVEY RESEARCH 1 9 61 

392. THE RIO GRANDE TROUGH NEAR ALBUQUERQUE, NEW MEXICO 

By H. R. JoESTING, J. E. CAsE, and L. E. CoRDELL, Washington, D.C., Berkeley, Calif., and Albuquerque, 

N.Mex. 

Gravity and aeromagnetic surveys have been made of 

part of the Rio Grande trough and adjoining areas 

near Albuquerque, N. l\1ex., to learn more about the 

structural boundaries and configuration of the trough. 

The area covered by the gravity and aeromagnetic surveys is shown on figure 392.1. 

0 

0 

~ ~~~~~~~~~~ 

0 

8 

0 10 20 

z 

iii 

<( 

m 

<( 

(j 

z 

~ en 

w 

30 40 50 MILES 

~~~--~--~--~ 

FIGURE 392.1.-Sketch map of part of Rio Grande trough and 

associated structures in north-central New Mexico. Area 

. studied crosshatched. Structural boundaries from Kelley, 

1952. 

The Rio Grande trough (Kelley, 1952, 1954; Fitzsimmons, 1959) is a series of complexly faulted troughs 

or basins, arranged en echelon. It extends from the 

northern end of the San Luis valley in Oolorado, southward 450 miles along the course of the Rio Grande 

in New l\1exico, to near El Paso, Tex. The trough is 

bounded on the west by the Colorado Plateau and on 

the east by uplifts of' the southern Rocky Mountains. 

The Albuquerque basin, the largest basin of the Rio 

Grande trough, is about 90 miles long and 30 miles wide. 

It is bounded by the Sandia, l\1anzanita, and Manzano 

uplifts on the east, by the Lucero uplift and Puerco 

platform on the west, and by the southern end of the 

Nacimiento uplift on the north west. Small· volcanoes 

and fissure flows mark the boundaries at several localities. The basin is filled with poorly consolidated Cenozoic deposits whose constituents were eroded from the 

uplands. Older sedimentary rocks doubtless underlie 

the valley fill. The thickness of sedimentary rocks is 

unknown, but Precambrian rocks may lie 10,000 feet 

below sea level in parts of the basin, whereas they are 

about 9,000 feet above sea level in the Sandia uplift and 

about sea level in the Puerco platform. 

BOUGUER GRAVITY MAP 

A large gravity low shown on figure 392.2 is on the 

valley fill (density about 2.3 g per cm3 ), and prominent 

highs are on the denser sedimentary and crystalline 

rocks of the bordering uplifts (densities about 2.45 to 

2.7 g per cm3 ). Steep gradients between the low and 

the highs mark major bounding fault zones. 

East of the trough, steep gravity gradients coincide 

in part with scarps along the mountain fronts, and with 

the projection of the Hubble Springs fault (Kelley, 

1954). As some of the steeper gradients are several 

miles farther west, parts of the main fault zone are 

evidently covered by consolidated material. 

A fault zone bounds the west side of the trough as 

shown by steepened gradients. They are less pronounced than on the east, because the comparatively 

dense Precambrian and Paleozoic rocks are covered by 

several thousand feet of less dense Mesozoic rocks; in 

addition, the fault zone may be wider. To the south 

steep gradients coincide with the faulted eastern flank 

of the Lucero uplift. At U.S. Highway 66 the contours bulge northeastward, indicating a buried extension of the Lucero uplift. A similar bulge on the eastern side constricts the trough. North of U.S. Highway 

66 the west margin of the trough trends north, about 

parallel to observed a.nd inferred faults. The Ignacio 

monocline is marked by a broad gravity high. 

Some of the closed gravity lows within the trough 

may coincide with comparatively great thicknesses of 

low -density valley fill. If so, the ancient drainage may 

have been west of the present Rio Grande, except to the 

south near Los Lunas. Conversely, some of the prominent highs may represent uplifted blocks of the denser 

Paleozoic and Precambrian rocks and thinner valley 

fill. The most prominent high, in addition to the positive bulges already mentioned, is west of Bernalillo. 
A 

EXPLANATION 

SEDIMENTARY ROCKS 

G }I Sedimentary deposits with 

interbedded lava flows 

L;A+:::·:j }! Shale and sandstone 

u 

~Pzli§ . Limestone H a.. 

IGNEOUS AND 

METAMORPHIC ROCKS 

~ }I . Basalt flows, 

cones, and dikes 

~,.-

Normal fault 

Ball on downthrown side; 

N 

dashed where inferred 

1 

- ::::::::--- -

Minor faults 

__ ,oo--

Gravity contour 

Dashed where uncertain. Contour 

interval is 5 milligals. Gravity 

values are simple &uguer anomoly for a reduction density of 2.45 

g per ems, plus 900 milligals 

0 5 10 MILES 

FIGURE 392.2.-Preliminary gravity map and generalized geologic map of Rio Grande area near Albuquerque, N. Mex. 

U2 

P:1 

0 

::tl 

8 

I'd 

> I'd 

t.".l 

::tl 

U2 

~ 

z 

8 

P:1 

t.".l 

0 

t.".l 

0 

t"4 

0 

0 

'"=' Q 

t:j 

~ 

P1 

~ 

t:j 

::tl 

0 

t"4 

0 

0 

"'"' 0 

r.Jl 

0 

~ 

t.".l 

~ t.".l 

SJ1 

> ::tl 

j 

0 

t"4 

t.".l 

r.Jl 

~ 

(0 

t.) 

I 

~ 

~ 

01 

t; 

~ 

~ 
D-284 GEOLOGICAL SURVEY RESEARCH 19 61 

An anaJysis of the gravity anomaly across the Rio 

Grande 'trough is shown on figure 392.3. A residual 

gravity low of about 45 milligals is superimposed on 

an assumed linear regional gradient. The density of 

the Cenozoic fill probably increases with depth, but the 

depth at which this becomes significant is unknown. 

The assumed density of the Mesozoic and Paleozoic 

rocks (2. 45 g per cm3 ) may be somewhat low, especially 

for the deeply buried rocks in the trough. 

On the basis of densities shown on figure 392.3, the 

total thickness of sedimentary rocks in the trough is estimated to be about 15,000 feet, and the total relief of 

the Precambrian basement along the Sandia front about 

20,000 feet. These values are approximations only as 

they depend in part on estimated rock densities. Single 

fault planes were assumed along the margins of the 

trough, although displacement probably occurred along 

many steeply dipping step faults. 

AEROMAGNETIC PROFILES 

Aeromagnetic profiles across the Rio Grande trough 

are shown on figure 392.4. The large magnetic highs 

are associated with the uplifted, comparatively magnetic crystalline rocks bordering the trough ; smaller, 

local highs are associated with volcanic rocks. The sedimentary rocks are essentially nonmagnetic. In general, 

the profiles and gravity map are in agreement. 

The magnetic anomalies are Teln,ted to variations in 

both the magnetization and uplift of the Precambrian 

rocks. For example, the magnetic susceptibility of the 

eastern part of the exposed Precambrian rocks near 

Albuquerque is very low, whereas along the western edge 

150 

140 

en 130 

it is moderately high (about 0.004 cgs units) . The 

remanent magnetization is generally low throughout. 

The magnetic contrast is reflected in the peak and the 

sharp eastward decrease of profiles 11 and 12. The profiles also show that the more magnetic rocks extend 

westward some 2 miles from the mountains under outwash material. The main fault zone near Albuquerque 

therefore coincides approximately with the Hubble 

Springs fault (shown on fig. 392.2). 

At the north end of the· Sandia uplift, the smaller 

amplitude of the profiles is probably related primarily 

to lowei; magnetization of the Precambrian rocks. Still 

·fu;rther north they reflect the apparent right lateral offset of the Rio Gtande trough, which is shown more 

clearly by the gravity contours. 

At the west ends of lines 9 to 12 there is little n1agnetic 

expression of the buried structural boundary of the 

trough. The small anomalies on profiles 10 and 12, 

southwest of the large area of volcanic rock, agree in 

position with the bordering gravity anomalies, but they 

may be caused by shallow volcanic rocks r.ather than 

displacement of the basement. Volcanoes, however, are 

commonly alined along the borders of the trough. 

North of line 9 the basement rocks are more magnetic 

and appear to delineate clearly the western edge of the 

trough. The fault zone is probably defined by the 

inflection points on the profiles. 

Analyses of two aeromagnetic profiles using the polar 

chart of Pirson ( 1935) are shown in figures 392.5 and 

392.6. The shapes and magnetic susceptibilities of the 

Precambrian rocks were arbitrarily chosen so that the 

computed and observed effects are in reasonable agree-

..J 

<(· 120 " x=computed gravity anomaly 

::J 

..J 110 ~ 100 

90 

80 

A 

10,000 

5000 

Sea level 

-10,000 

Rio Grande 

Cenozoic rocks 

__ __ P=2.3 g perc~ _____ _ 

Mesozoic and Paleozoic(?) rocks 

P=2.45 g per cm3 

0 5 10 MILES 

A' 

Sandia crest 

Precambrian rocks 

p=2. 7 g per cm3 

FIGURE 392.3.-An interpretation of the gravity anomaly across· the Rio Grande trough north . of Albuquerque,· N. Mex. 

,.. 
~ 

Czs 

35"0~ ~:~;~;~6;;··~· ) 

I 

/ 

I 

\ 

Czs 

1 

106°30' 

f}czb 

Czs 

Geology after C. H. Dane 

and G. 0. Bachman, 1957 

0 

I 

EXPLANATION 

SEDIMENTARY ROCKS 

G }I Sedimentary deposits with 

interbedded lava flows 

. [:~~p~i:\) r u 

0 - NO O .oz g LU<t:lll 

Shale, sandstone, and limestone -l LU 

~ ~ 

IGNEOUS AND 

METAMORPHIC ROCKS 

u 

}I Granite and metamorphic 

rocks 

undivided 

L2 

Flight line 

Magnetic 

~ profile for 

corresponding flight 

line 

t200 100 

0 

Vertical scale in gammas 

5 10 MILES I I 

FIGURE 392.4.-Magnetic profiles, flight lines, and generalized geologic map of Rio Grande area near Albuquerque, N. M:ex. 

l/1 

~ 

0 

::tl 

1-3 

"'d 

> "'d 

trl 

::tl 

U1 

~ 

z 

~ trl 

0 

trl 

0 

~ 

0 

0 

~ 

Q 

~ t;:; 

~ 

~ 

t;:; 

::tl 

0 

t-4 

0 

0 

...,... 

Q 

rp 

0 

~ 

trl 

~ trl 

~Ul 

> 

::tl 

1-3 

~ 

f3 

trl 

U1 

!);) 

co 

Cl:l 

I 

~ 

Cl:l 

C1t 

t:1 

~ 01 
D-286 GEOLOGICAL SURVEY RESEARCH 1 9 61 

en 

<( 

800 

600 

~ 400 

<3 

200 

0 B --~ 

1 

I 

Observed j 

magnetic / 

profile ~ 

I Computed 

magnetic 

/ 

/ 

/ 

/ profile 

~ 

\ 

\ 

\ 

~ 

\ 

\ 

B' 

8,000 .----------.:....:..:.!;~.::..:..::.:.l-________ -----, 

Sea 

level 

-10,000 

-20,000' 10,000 

Sedimentary 

rocks 

K=O 

20,000 30,000 

FEET 

40,000 

rocks 

50,000 

FIGURE 392.5.-An interpretation of the magnetic anomaly across 

the eastern boundary of the Rio Grande trough, southeast of 

Albuquerque, N. Mex. 

ment. Reasonable agreement was obtained when the 

Precambrian rock in the trough was placed at -16,000 

feet, sea level datum. Assuming a lesser depth would 

have required flattening of the fault planes, or assigning more than one susceptibility. On figure 392.5 the 

departure of computed and observed profiles along their 

west flank indicates either that the susceptibility of the 

down-faulted basement increases westward, or the slope 

of the fault decreases, perhaps step-fashion. The indicated displacement of the basenient is nearly 22,000 feet 

10,000 

10,000 20,000 30,000 

FEET 

40,000 

Sedimentary 

rocks 

50,000 60,000 

FIGURE 392:6.-An interpretation of the magnetic anomaly across 

the western boundary of the Rio Grande trough, northwest of 

Albuquerque, N. Mex. 

along the Sandia front, and 16,000 feet on the west side. 

These estimate's are in reasonable agreement with those 

based on gravity interpretations; but the correctness of 

both depends on the degree of correctness of the assigned 

magnetic susceptibilities and densities. 

REFERENCES 

Dane, C. H., and Bachman, G. 0., 1957, Preliminary geologic 

map of the northwestern part of New Mexico: U.S. Geol. 

·survey Misc. Geol. Inv. Map I-224. 

Fitzsimmons, J. P., 1959, The structure and geomorphology of 

west-central New 1\iexico: a regional setting, in New 

Mexico Geol. Soc. Guidebook of west-central New Mexico, 

lOth Field Conf.: p. 112-116. 

Kelley, V. C., 1952, Tectonics of the Rio Grande depression of 

central New Mexico, in New Mexico Geol. Soc. Guidebook 

of the Rio Grande country, 3rd Field Conf.: p. 93-105. 

--- 19>54, Tectonic map of part of the upper Rio Grande area, 

New Mexico: U.S. Geol. Survey Oil and Gas Inv. Map 

OM-157. 

Pirson, S. J., 1935, Polar charts for interpreting magnetic 

anomalies : Am. Inst. Min. Metall. Engineers Gontr. 9L 

(' 

{ 

r 
SHORT PAPERS IN THE GEOLOGJiC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-287 

393. PRECAMBRIAN STRUCTURES IN THE BLANDING BASIN AND MONUMENT UPWARP, SOUTHEAST UTAH 

By J. E. CAsE and H. R. JoESTING, Berkeley, Calif., and Washington, D.C. 

Work done partly in cooperation with the U.S. Atomic Energy Oommi8Bi.on 

Prominent aeromagnetic and gravity anomalies in 

the Blanding basin and Monument upwarp of southeast Utah trend northeast (figs. 393.1 and 393.2) 

t:l·ansverse to other geophysical anomalies and regional 

:folds of Laramide ( ~) age. Sources of these transverse 

anomalies are evidently within rocks of the buried 

Precambrian basement. Analogous transverse trends 

have been detected by geophysical investigations in the 

northwest-trending Paradox fold and fault belt north 

of the Blanding basin ( J oesting and Case, 1960, figs. 

114.2, 114.3; Joesting and Byerly, 1958; Byerly and 

~J oesting, 1959). 

Summaries of the geology of southeast Utah, including the Blanding basin and Monument upwarp, can be 

found in reports by Baker ( 1935), Kelley ( 1955), Shoemaker (1954), and Lewis (1958). Briefly, the Monument upwarp is a broad asymmetric fold whose axis 

has a general northerly trend. The adjoining Blanding basin luts no pronounced axial trend. Comb Ridge 

monocline is the bounda.ry between the basin and upwarp, and has about 4,000 feet of structural relief (fig. 

393.3). 

The Preca1nbrian basement lies beneath 8,000 to· 

9,000 feet of Paleozoic and Mesozoic rocks in the Blanding basin and beneath 2,000 to 6,000 feet on the Monument upwarp where most of the Mesozoic beds have 

been removed by erosion. The configuration of the 

Precambrian surface can be inferred from the altitude 

of Mississippian and older Paleozoic rocks in wells in 

the region (fig. 393.3). The interval between the top 

of the Mississippian and the Precambrian surface is 

about 2,000 feet at the northern end of Elk Ridge; 

about 1,300 feet near Bluff, and about 1,000 feet near 

Eastland. The form of the Precambrian surface reflects mainly Laramide folding of the region, but relief 

of the basement may be as much as 1,000 feet greater 

than relief of Triassic beds between basin and upwarp. 

Because Paleozoic and Mesozoic sedimentary rocks of 

the region are virtually nonmagnetic ( J oesting and 

Byerly, 19·58, p. 4-5), sources of aeromagnetic anomalies 

shown on figure 393.1,are thought to be within the Precambrian basement, except for those associated with the 

lacco]ithic intrusions of the Abajo Mountains. The 

relatively simple configuration and low relief of the 

Precambrian surface, except at Comb Ridge monocline, 

can accouJ1t for only a small part of the observed magnetic anomalies; sources of the larger gravity anomalies 

are probably density contrasts within basement rocks. 

Structural relief of the basement can account for only 

a few milligals of the 30-milligal low in the Blanding 

basin or the low near Cedar Mesa (fig. 393.2). Thickening of evaporites within the Paradox evaporite member of the Hermosa formation of Pennsylvanian age 

can likewise account for only a few milligals of the 

gravity lows, as the thickness of the member changes 

gradually northward from 100 feet at Mexican Hat to 

1,500 feet at Monticello (Wengerd and Matheny, 1958, 

fig. 16, p. 2090-2091). 

Prominent aeromagnetic anomalies extend northeast 

from Cedar Mesa, across Comb Ridge, to Eastland 

(A-A', fig. 393.1), and from Comb Ridge to the north 

edge of the map area (B-B'). Gravity lows of 20 to 30 

milligals, near Cedar Mesa and in the Blanding basin, 

are bordered on the southeast by nearly straight contours from south of Cedar Mesa to Comb Ridge, and 

from north of Bluff to Eastland (A-A', fig. 393.2). 

The lows are bordered on the northwest by relatively 

straight contours from northern Cedar Mesa to Comb 

Ridge, and from Blanding to the north edge of the area 

(B-B'). The axis of the gravity low in the Blanding 

basin extends northeast, and the low near Cedar Mesa 

is on the same trend, but the lows are interrupted by a 

gravity high parallel to Comb Ridge. These gravity 

and magnetic effects are probably caused by a deepseated block of Precambrian rocks of low density and 

irregular magnetization, bordered· by faults, as inferred 

from the straightness and close-spacing of the geophysical contours along A-A' .and parts of B-B'. The 

northwestern margin of the block is not everywhere defined by magnetic data, partly because of effects of laccolithic intr:usions in the Abajo Mountains and of buried 

magnetic masses near Blanding. 

A simplified analysis of the gravity low in the Blanding basin, which neglects. effects of laccoliths in the 

Abajo Mountains, shows that the block of low-density 

basement rocks extends downward about 12,000 feet, 

assuming a density contrast between rocks inside and 

outside the block of 0.3 g per cm3 (fig. 393.4). Such a 

contrast would exist, for example, between granite or 

quartzite (density about 2.6 to 2.7 g per cm3 ) and some 

of the denser metamorphic, mafic or ultramafic rocks 

(densities about 2.8 to 3.1 g per cm3 ). A smaller den-
D-288 GEOLOGICAL SURVEY RESEARCH 19 61 

0 5. 10 20 30 MILES 

---700---

Magnetic contour 

Contours show total intensity 

relative to an arbitrary datum Contour intervallOO gammas 

A IIIIIIIIIIIIIPIIIIIIIIIIIIA"' 

Inferred structural boundary 

within Precambrian basement 

Queried wh£re position uncertain 

Area A flown at 11,500 feet 

above sea level; all remaining at 8500 feet 

FIGURE 393.1.-Preliminary aeromagnetic· map of parts of Blanding basin and Monument upwarp, Utah and Colorado. · 
.~ 

SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-289 

10 5 0 10 20 MILES 

I 

'Or-118 < < E-< ~ 

~s 0 

10 

I 

-- 100 --?--

Gravity contour 

Dashed where uncertain. Que?Wd 

WMre doubtful. Contour interval 

10 milligals. Contour values are 

900 milligals higher than Bouguer 

anomaly values for a density of 

1!.5 grams per culnc centimeter 

AIIIIIIII?IIIIIIIIA' 

Inferred structural boundary 

within Precambrian basement 

Queried wMre position uncertain 

c f---------'-~ c I 

Line of profile 

Fmuml: 3!)3.2.-Preliminary gr!lVity anomaly map of parts of Blanding basin and Monument upwarp, Utah and Colorado. 

See profile C-0' on figure 393.4. 
D-290 

! ~£ 2252 

... p£ 1600 

~ 

(J 

5 0 

GEOLOGICAL SURVEY RESEARJCH 1 9 6 1 

5 10 15 

0 

Monticello 

?---........ ~ I £-1827 ·y I 

p£ -2ooo , Eastland~ 

% 0 

\ 

. £ -1583~, p£ -2000 \ 

\ 

I 

I 

20 MILES 

EXPLANATION 

---1500-?-

Form line showing estimated 

elevation of Precambrian 

surface 

Queried where uncertain. Contour 

interval 500feet; datum is mean 

sea level 

f£ 1834 

Drill hole penetrating Precambrian rocks showing elevation of top of Precambrian surface 

+M 2948 

p£ 1900 

Drill hole penetrating Mississippian or older rocks showing estimated elevation 

of top of Precambrian 

M, Mississippian 

D, Devonian 

£,Cambrian 

Estimates of thickness of Mississippian, Devonian, and Cambrian strata were guided by 

isopach maps of Cooper, 1955, 

Barrs, 1958, and Neff and 

BroWn 1958 

FIGURE 393.3.-Inferred configuration of the Precambrian surface in parts of Blanding basin and Monument upwarp, 

Utah and Colorado. 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-291 

~ 

~ ~ 

~ z 1261 120 :a ~ ! 

- o..~, 

--uo -12 ~ ~ -16 o( 

~ 100 =~~ ~ ~ -28 z 1-' 90 -32 o( 

s 86 -36 s ~ 5 Lol a. II) ::E 

~ 8 

Computed gravity ,,-o anomaly~,.o;'' 

; 

_,,A Observed gravity 

.,u. anomaly 

~---...... --!!:..~""'...-

8 c C' 9000t ... ------------~Su~r!!:fa~ce~of~g~r~ou~n~d- SEA LEVEL ~ PALEOZOIC AND MESOZOIC SEDIMENTARY ROCKS 

- 4000 ~ ------ "PR"EcA"t.~8"RIA'N"'Rc5CisoFL'Ow- "PR"EcAi.lliRiA"N- _16.000 ~ DENSITY AP= -0.3 G PER CM 3 ROCKS OF" 

1o1 RELATIVELY 

;;:J HIGH DENSITY 

0 10 15 MILES 

l!,rouuE 393.4.-Interpretation of the gravity anomaly over the 

Blanding basin, Utah, along profile 0-0' shown on figure 393.2. 

sity contrast,· of course, would require a thicker block 

of low-density rocks to produce the gravity low. 

The prominent magnetic lows in the low-density area 

'nay be caused in part by remanent magnetization of 

rocks in directions about opposite to magnetization induced by the earth's present field, rather than by low 

susceptibility. Their irregularity does not permit 

analysis in terms of geometry or thickness of sources. 

The Precn.mbrian rocks, however, are evidently largely 

granitic rather than quartzitic, as the data require that 

they have a comparatively low density and a moderately 

wide range of magnetization. 

The source of the ·large magnetic high and residual 

gravity high at Blanding is obviously a comparatively 

dense and mn,gnetic rock. The estimated elevation of 

the source of the Blanding anomaly is about - 2,000 feet 

(sen, level datum), based on the method of Vacquier and 

others ( 1951). The basement may therefore be shallower near Blanding than estimated from stratigraphic 

data. 

The area of low density and generally moderately 

magnetized basement rocks, which are probably granitic, is about 20 miles wide and 50 miles long. Other 

northeast-trending Precambrian structures have been 

inferred near Upheaval Dome, Utah; northwest of the 

La Sal Mountains, Utah; and near Cisco, Utah ( J oesting and Case, 1960, figs. 114.2, 114.3; Case and Joesting, 

1961). These northeast-trending structures in the 

central Colorado Plateau are evidently part of an 

ancient regional structural pattern which may include 

transverse zones such as the northeast-trending Colorado mineral belt of the southern Rocky Mountains. 

REFERENCES 

Baars, D. L., 1958, Cambrian stratigraphy of the Paradox basin 

region, in Intermountain Assoc. Petroleum Geologists Guidebook 9th Ann. Field Conf., Guidebook to the geology of 

the Paradox basin, 1958: p. 93-101. 

Baker, A. A., 1935, Geologic structure of southeastern Utah: 

Am. Assoc. Petroleum Geologists Bull., v. 19, no. 10, p. 

1472-1507. 

Byerly, P. E., and Joesting, H. R., 1959, Regional geophysical 

investigations of the Lisbon Valley area, Utah and Colorado: U.S. Geol. Survey Prof. Paper 316-C. 

Oase, J. E., and Joesting, H. R., 1961, Northeast-trending Precambrian structures in the central Colorado Plateau (abs.): 

Geol. Soc. America, Program, R-ocky Mountain Sec~ion 

Meeting, Laramie, 'Vyo., p. 13. 

Cooper, J'. C., 1955, Cambrian, Devonian, and Mississippian 

rocks of the Four Corners area : Four Corners Geol. Soc. 

Field Conf. Guidebook, p. 59-65. 

Joesting, H. R., and Byerly, P. E., 1958, Regional geophysical 

investigations of the Uravan area, Colorado: U.S. Geol. 

Survey Prof. Paper 316-A. 

Joesting, H. R., and Case, J. E., 1960, Salt anticlines and deepseated structures in the "Paradox basin, Colorado and Utah, 

in Short papers in the geological sciences: U.S. Geol. Survey 

Prof. Paper 400-B, p. B252-B256. 

Kelley, V. C., 1955, Regional tectonics of the Colorado Plateau 

and relationship to the origin and distribution of uranium: 

New Mexico. Univ. Pub. Geology, no. 5, 120 p. 

Lewis, R. Q., 1958, Structure of the Ell\: Ridge-Needles area, 

San Juan County, Utah, in Intermountain Assoc. Petroleum 

Geologists Guidebook 9th Ann. Field Conf., Guidebook to 

the geology of the Paradox basin, 1958 : p. 78-85. 

Neff, A. W., and Brown, S. C., 1958, Ordovician-Mississippian 

rocks of the Paradox basin, in Intermountain Assoc. 

Petroleum Geologists Guidebook 9th Ann. Field Conf., 

Guidebook to the geology ·of the · Paradox basin, 1958 : 

p. 102-108. 

Shoemaker, E. M., 1954, Structural features of southeastern 

Utah and adjacent parts of Colorado, New Mexico, and 

Arizona.: Utah Geol. Soc., Guidebook to the geology of 

Utah, no. 9, p. 4~69. 

Vacquier, Victor, and others, 1951, Interpretation of aeromagnetic maps: Geol. Soc. America Mem. 47, 151 p. 

Wengerd, S. A., and Matheny, M. L., 1958, Pennsylvanian system 

of Four Corners region : Am. Assoc. Petroleum Geologists 

Bull., v. 42, no. 9; p. 2048-2106. 
D-292 GEOLOGICAL SURVEY RESEARJCH 19 61 

394. USE OF GEOPHYSICAL DATA TO INTERPRET GEOLOGY IN PRECAMBRIAN ROCKS OF 

CENTRAL WISCONSIN 

By JOHN W. ALLINGHAM and RoBERT G. BATEs, Washington, D.C. 

The oldest Precambrian rocks in the Driftless Area 

around Wausau, vVis., consist of a complex sequence of 

V1olcanic, pyroclastic, and sedimentary rocks that has 

been metamorphosed to greenschist and amphibolite 

facies. These rocks are intruded by granite and associated granophyre, and by syenite, diorite, and diabase 

(fig. 394.1). The area is a plain of low relief covered 

mostly by residual soil, with so:r;ne glacial debris and 

loess. Hills of quartzite rise above the plain at a few 

places.· 

The rocks within the Wausau area can be divided into 

several groups according to their density, magnetic 

susceptibility and radioactivity (tables 394.1 and 394.2). 

Areas underlain by syenite, quartzite and various types 

of granite can be distinguished by well-defined radioactivity anomalies caused by different suites of accessory minerals. Areas underlain by gray granite, 

diorite, hornblende diorite, and diabase can be distinguished by distinctive aeromagnetic patterns, which 

are directly related to the magnetite content of the rock 

units. 

Figure 394.2 shows the total magnetic intensity over 

the area covered by the provisional geologic map (fig. 

394.1). Figure 394.3 shows the geology and aeromagnetic profiles along lines 36 and 99 on figures 394.1 and 

394.2. Comparison of the aeromagnetic profiles with the 

geology (fig. 394.3) shows many interesting relations 

that can be used to interpret the geology over the larger 

area of figure 394.2. 

On figure 394.3, for example, line 36 crosses two inversely polarized diabase dikes (a) that appear as sharp 

magnetic lows in chlorite schist (b). Diorite (c) and 

metabasalt (d), are markedly more magnetic than 

granite (e), and greenstone (f). Normally polarized 

diabase dikes (g) are also more magnetic than greenstone (f). The profile along line 99 of figure 394.3 

TABLE 394.1:--Physical properties of rocks in Wausau area 

Rock 

Red granite: t 

Northeast of Wausau _________________________________ _ 

Southwest of Wausau ______________________________ ..., __ _ 

Syenite: Northwest of Wausau _________________________________ _ Skarn _________________________________________________ _ 

Basalt or greenstone ____________________________________ _ 

Hornblende diorite _____________________________________ _ 

1 Quarry samples: 

Number 

or 

samples 

14 

20 

18 

20 

40 

22 

Density 

Average Range 

2. 67 2. 65-2. 68 

2. 68 ------------

2. 80. ------------ 2. 82 2. 78-2. 85 

3. 0 2. 96-3. 08 

3. 1 ------------

Magnetic susceptibility x 10-a cgs 

Average Range 

0. 3 Q. 1-0. 4 

. 05 . 02-0. 07 

1.4 0. 9-2. 0 

4. 0 2. 3-48 

5. 0 1. 1-12 

6. 0 4. 8-7. 8 

Magnetite 

(percent 

by volume) 

0. 2 

----------

.7 

1.5 

1.9 

2. 4 

TABLE 394.2.-Totai-inten~ity magnetic fields and. radioacti.vity 

levels associated with common rock types in Wausau area 

·shows the well-defined borders of hornblende diorite 

(h) .and some minor variations in areas mapped as 

schist (i) and rhyolite (j). Totalintensity 

anomaly in 

gammas 

0-200 

20Q-500 

50Q-3000 

Radioactivity level in counts per second 

lOo-300 30Q-8CO 50Q-1000 

Quartzite ______ Syenite north- Red granite 

west of southwest of 

Wausau. Wausau. 

--------------- Skarn _________ Gray granite. 

Hornblende Basalt or 

diorite. greenstone. 

The arcuate high-amplitude magnetic anomalies (No. 

1, fig. 394.2) are caused by skarn and associated granulite in the central area of red granite and in the adjoining area of aplitic syenite. These rocks, together 

with spatially related quartzite and chlorite-albite 

schist, outline limbs of a large fold. Dip directions of 

the metamorphosed sedimentary rock units, obtained 

by comparing computed magnetic curves with observed 

profiles, indicate that this fold· is the keel of a south-
Jo 

-' 

45 ~ ·t!1!~1~:=rr~~~J.~ff~~tf:f?: t)~~1J~~J!1~!l~~lfll~ 

EXPLANATION 

INTRUSIVE ROCKS 

E3 

Diabase dikes 

Red ~ granite 

Granophyre 

~ 

~ 

t-:-:::-:->:-:~-:-1 Gray granite 

Syenite 

~ 

~ 

Nephe~yenite ~ 

~ 

Diorite 

c=J 

Hornblende diorite 

EXTRUSIVE ROCKS 

N::=;-~-:::::-\:\·1 

Rhyolite 

Includes pyroclastic rocks 

[3] 

Andesite 

t:=.:~:::::·i 5'1~;~;~~J 

Greenstone Basalt 

SEDIMENTARY ROCKS 

c=J 

Alluvium 

Chlorite-albite ~ schist 

Biotite ~ schist 

nmmnmnl 6tillSill 

Quartzite Skarn 

Bedrock not mapped 1-.'l'·-.. I Numbers show location of 

areas discussed in text. 

0 5 MILES 

Geology compiled from following unpublished maps: 

Township surveys by Wisconsin Geological and 

Natural History Survey, 1922-23; R. C. Emmons 

and F. G. Snyder, 1944; and J. W. Allingham 

and R. G. Bates, 1958 

FIGURE 394.1.-Provisional geologic map, Wausau area, Wisconsin. 

U1 

~ 0 

::tl 

1-3 

'"d 

> '"d 

l:?j 

::tl 

U1 

z 

~ l:?j 

0 

l:?j 

0 

t" 

0 

0 

t.i 

~ t=' 

~ t=' 

::tl 

0 

t" 

0 

0 

........ 

0 

~ ........ 

l:?j 

~ (') 

l:?j 

_Ul 

> ::tl 

j 

fa 

l:?j 

U1 

t-:) 

c:l 

c.:> 

I 

~ 

c.:> 

CJ1 

tJ 

I 

~ 

co 

(J.j 
V' 

tj 

~ c:.o 

~ 

IDI " V;[J \ WLJ'I ~(/-: - ocnl EXPLANATION :1 ~ 5 (()\ ,v ~ : 

?:1 ~ ~ 10 ?: 

-'j (Q) ,1•0 it5 0 _, ~ f) ) ~~ ~ ~~0 ~gootlownUmm,oho~ngWbl intensity magnetic field of the earth in gammas relative to ar-. bitrary datum; hachured to in- dicate closed area of lower mag- netic intensity; dashed where data incomplete 

4175 

X 

Measured maximum or minimum intensity within closed magnetic high or closed magnetic low 

0 

'"-'- 1-----------" I I \1 ~~ _/ II I 1 I v-/ I \ ~~ ~--:.:. \'. I /l ~ ~ "'- / \ I .. - - '- ~ 

0 10 

Outline of syncline b 

0 

>< ~ Axis of syncline ~ 

!;:tl 

< t'j 

WISCONSIN ~ .... 00 !;:tl 

\-)

·--·- . ?h 

t'j 4'>" > 

l:J:j 

H ~ INDEX MAP 

Numbers show location of · 

....... 

co 

C) 

....... 

. _ _ _ . , , areas discussed in text. 

0 5 MILES 

Contour interval 250 gammas 

FIGURE 394.2.-Total-intensity aeromagnetic map, Wausau area, Wisconsin. 

r ·' 
I 

SHORT PAPERS IN THE GEOLOGI'C AND HYDROLOGIC SCIENCES, ARTICLES 293-435 

4250 

3750 

(f) 

<( 

~ 

~ 

<( 

(!) 3250 

2750 

1500'j 

Sea 

level 

5000 

(f) 

<( 

~4000 ~ 

<( 

(!) 

South North 

Line 99 

0 5 MILES 

FIGURE 394.3.-Aeromagnetic profiles along lines 36 and 99 on figures 394.1 and 394.2 showing correlation with geOlogy, 'Vausau area, Wisconsin. 

D-295 
D-296 GEOLOGICAL SURVEY RESEARCH 1961 

west-plunging major syncline. This syncline has been 

partly obscured by volcanic rocks and by engulfing 

felsic and mafic intrusions. 

Diabase dikes of reverse magnetism (No. 2), which 

extend for as 1nuch as 12 miles across the central part 

of the area (Bates and Allingham, 1958) , are seen 

clearly on figure 394.2 as sharp, continuous magnetic 

lows. These dikes contain accessory titaniferous spinel, 

which produces the reversed remanent magnetization. 

The area of chlorite-albite schist on the west edge of 

figure 394.2 is outlined fairly well by the 3250 gamma 

line (No. :3) . 

The circular magnetically zoned anomaly (No. 4) 

within the syenite complex northwest of Wausau is possibly an alkalic plug. If so, this area might be geologically favorable for exploration for niobium-bearing 

minerals, because this association of a circular zoned 

intrusion, hornblende diorite, and pyroxenitic rocks 

with syenite is similar to an occurrence in Ontario Province, Canada, that yields niobium (columbium) -bearing pyrochlore (vVestrick and Parsons, 1957). Spectrographic· analyses of samples from the syenite 

(Vickers, 1956) show concentrations of niobium. 

The gray granite northeast of vVausau is distinguished by a large magnetic low (No. 5) . This granite is surrounded by a sinuous belt of metabasalt or 

mafic diorite that gives magnetic highs (No. 6). The 

pronounced and circular magnetic high (No. 7) northwest of No. 6 may represent a plug that is a. possible 

source of these mafic rocks. 

Some geologic boundaries are also sharply defined 

by the aeromagnetic information. The margins of the 

hornblende diorite east of Wausau (No. 8) and of the 

basalt south of "\Vausau (No. 9) are clearly indicated. 

Areas of red granite (No. 10) and rhyolite and pyroclastic rocks (No. 11). are magnetically flat, and thus 

are less clearly defined. 

These observations show that geophyical data can 

add significantly to knowledge of geology in areas of 

complex structure and poor exposures. 

REFERENCES 

Bates, R. G., and Allingham, J. W., 1958, Correlations of air-

. borne geophysical data with geology in the ·wausau area, 

Wisc~:msin [abs.] : Geophysics, v. 23, no. 5, _p. 1068. 

'Vestrick, E.· W., and Parsons, G. E., 1957, 'Integrated exploration finds columbium deposits in Chewett and Collins townships, Ontario, in Methods and case histories in mining 

geophysics, [Canada] Commonwealth Mining and Metall. 

Cong. (6th) : p. 184-195. 

Vickers, R. C .. , 1956, Airborne and ground reconnaissance of 

part of the syenite complex near Wausau, Wisconsin: 

U.S. Geol. Survey Bull.1042-B., p. 32-33. 

395. SOME OBSERVATIONS OF THE SEISMIC-ELECTRIC EFFECT 

By C. J. ZABLOCKI and G. V. KELLER, Denver, Colo. 

Work done in cooperation with the U.S. Air Force and the U.S. Atomic Energy Commission 

Several mechanisms have been postulated for the conversion of mechanical energy in seismic waves to electrical energy in the earth. Thompson-(1939) suggested 

that the resistivity of a rock is increased during compression and decreased during tension, so that if a current is flowing through the rock when a seismic wave 

arrives, the potential gradient across the rock will vary 

according to Ohm's Law. Ivanov .(1939) considered 

that differential motion between rock grains and water 

in pore spaces can cause electrofiltration potentials as a 

·seismic wave· passes through a rock. Other possibilities 

are that the motion of a conductive rock in the magnetic 

field of the earth may generate an electric current, and 

that changes in pressure Q-.t the electrodes used to measure earth voltages may change the electrode potentials. 

The mechanism or mechanisms ordinarily involved 

in the seismic-electric effect have not been conclusively 

determined experimentally. Buklmikashvili and Pran· 

gishvili ( 1956) were not able to substantiate the existence of the electrofiltration phenomenon, but Martner 

and Sparks ( 1959) presented experimental evidence 

suggesting that voltages are generated at the base of 

the weathered layer. 

An opportunity for studying seismic-electric voltages 

developed by high-energy seismic waves was provided 

by the underground nuclear detonations included as 

part of the Hardtack II test site series at the U.S. 

Atomic Energy Commission's Nevada Test Site. Earth 

potentials were recorded at distances ranging from 3 to 

5 miles from these underground explosions, and, -more 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-297 

recently, at approximately the same distance from a 

large underground chemical explosion. 

Earth potential differences were measured between 

grounded lead electrodes 2,500 feet apart. Two orientations of electrode pairs were used at each recording 

location, one pair of electrodes placed along a radial 

line from the explosion, and another pair at a constant 

radial distance from the explosion. The voltages between en.ch pair of electrodes were amplified and recorded on a high speed oscillograph. The frequency 

response was 0 to 220 cycles per second, except that 

frequencies close to 60 cycles per second were rejected 

with a notch filter. Seismometers sensitive to ground 

velocity in the frequency range of 2 to 20 cycles per 

second were placed near each grounded electrode. The 

low-end response of these seismometers is down about 

10 decibels at 1 cycle per second from 2 cycles per second 

n.nd falls off sharply below 1 cycle per second. 

Records of seismic-electric voltages from two underground explosions are shown on figure 395.1 (p. D-298). 

The traces on the records are identified as follows: 

Scooter event : 

Trace number 1, Radial electric spread, full-scale 

sensitivity 1.8 mv 

Logan event : 

1a, Radial electric spread, full-scale 

sensitivity 0.6 mv 

2, Horizontal seismometer at vertex 

of "L" spread 

3, Transverse electric spread, fullscale sensitivity 1.8 mv 

3a, Transverse electric spread, fullscale sensitivity 0.6 mv 

Trace number 1, Radial electric spread, full-scale 

sensitivity 12 mv 

2, Tran~verse electric spread, fullscale sensitivity 12 mv 

3, Horizontal seismometer at vertex 

of "L" spread 

The first group of traces were recorded during the 

explosion of 500 tons of chemical explosives buried approximn,tely 80 feet in alluvium. The name of the 

opern.tion · was "Scooter event." The electrodes nearest the explosion point were at a radial distance of 3lj2 

miles to the southwest. The area between the explosion 

point and the recording station is underlain by alluvium 

about 1,000 feet thick, which rests on a bedrock surface consisting of volcanic tuff, limestone, argillite, 

quartzite, and conglomerate. 

The second group of traces shows the voltages 

recorded during the detonation ~fan underground nuclear device and the operation name was "Logan event." 

•604493-61-20 

The point of detonation was in volcanic tuff, approximately 800 fee~ b~low the surface of the earth. The 

energy released by the explosion was equivalent to that 

contained in approximn.tely 5,000 tons of T;NT (Griggs 

and Press, 1961). The recording station was 4.3 miles 

east of the explosion point on an outcrop of volcanic 

tuff. The area between the explosion point and the 

recording station was covered by no more tha.n a few 

tens of feet of alluvium. The voltages are sufficiently 

large and unique in character that they cannot be interpreted as variations in the normal telluric current field. 

Records made at this locality during several nuclear 

explosions were practically identical. The characteristics of the seismic-electric signals were : (a) Seismicelectric voltages in the radial direction were always 

larger than the voltages in the transverse direction. 

(b) The frequencies of the electric signals generally 

correlate with the low frequencies recorded on the seismic traces. Higher frequencies that were contained in 

the signals from the seismmneters were not apparent on 

the electric traces. (c) The first seismic-electric voltages at the electrode spreads appear essentially at the 

same time as the seismic energy. A plot of electric 

signal as a function of ground velocity (fig. 395.2, p. 

D-299) suggests that the electric signals lead the 

seismic signals by 45° in phase. Unfortunately, the 

freq~encies observed in the seismic records were close to 

the seismometer resonant frequency, and thus, all or 

part of this phase delay may have been in the mechanical system. 

The seismic-electric signals and the seismic waves 

from the chemical explosion persisted at significant 

levels for 90 seconds, but the signals from the nuclear 

explosion, which was nine times larger, lasted for only 

30 seconds. The alluvium in which the chemical explosive was detonated was probably a better medium in 

which to generate slow-moving seismic-surface waves 

th~tn were the volcanic rocks in which the nuclear explosion occurred. 

REFERENCES 

Bukhnikashvili, A. V., and Prangishvili, G. M., 1956, Experiments on the recording o'f the seismoelectric effect : Akad. 

Nauk Gruzin. SSSR, v. 18, p. 789-795. 

Griggs, D. T., and Press, F., 1961, Probing the earth with 

nuclear explosions: Jour. Geophys. Research, v. 66, p. 237-

258. . 

Ivanov, A. G., 1939, Effect of electrization of earth layers by 

elastic waves passing through them: Akad. Naul{ SSSR, 

Doklady, v. 24, no. 1, p. 42-45. 

Martner, S. T., and Sparks, N. R., 1959, Th~ electroseismic 

effect: Geophysics, v. 24, no. 2, p. 297-308. 

Thompson, R. R., 1939, A note on the seismic electric effect : 

Geophysics, v. 4, p. 102-105. 
TIME IN SECONDS 

0 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 28 29 30 

TRACE NO. 

2' ·----~---

3 

TIME IN SECONDS 

31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 

TRACE NO. 

~ LB I TNT -OCT. 13, 1960 CONTINUED 

TIME IN SECONDS 

0 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 

TRACE NO 

I I I 

LOGANIEVENT45 KT NUCLEAR-OCT. 15, 195f 

~ - -

2 

~ 

I I"~ f\ ~\ '- r" {"' ~ L "' t ' A I I ' ' I "' ;.... ' ' ' t\-'l.."r, ..-"'....-I ' /'--~-,..__ ..... 1-....... ,-~--.... --r---,_~-- ........... --.._ ____ _._ ___ _ I tl V'' I/ 'f !'- \' \t "' " 

\I \f V II 

3 -----1-----

FIGURE 395.1.-Records of seismic-electric phenomena. 

tJ 

~ co 

00 

0 

tzj 

0 

t'4 

0 

0 

~ t'4 

00 

~ 

!;0 

< tzj 

~ 

!;0 

l"=.J 

00 

l"=.J 

> l=!:l 

~ 

1-0 

co 

0) 
.., 

14.1 

0 

::::> 

.... 

::; 

Q. 

~ 

c( 

u 

a: 

.... 

u 

14.1 

_. 

14.1 

0 

i 

V) 

~ V) 

SHORT PAPERS IN THE GEOLOGI•C AND HYDROLOGIC SCIENCES, ARTICLES 293-435 

Time interval 0.25-0.35 seconds 

(Interval between points, 0.005 seconds) 

RELATIVE GROUND VELOCITY 

u 

a: 

.... 

u 

14.1 

_. 

14.1 

0 

i 

V) 

~ V) 

L.IJ 

> 

~ 

5 

14.1 

0:: 

Time interval 0.35-0.50 seconds 

(Interval between points, 0.005 seconds) 

RELATIVE GROUND VELOCITY 

D-299 

FmunE 395.2.-Plots of instantaneous seismic-electric signals versus instantaneous ground velocity for portions of record 

during chemical explosion. 

396. THE SIGNIFICANCE OF A GROUP OF AEROMAGNETIC PROFILES OFF THE EASTERN COAST OF 

NORTH AMERICA 

By ELIZABETH R. l{ING, IsiDORE ZIETZ, and WILLIAM J. DEMPSEY, Washington, D.C. 

Work done in cooperation with Office of Naval Research 

The 14 aeromagnetic profiles which form the basis of 

this study were obtained on flights by the U.S. Geological Survey in 1948 and 1950 and make a fan-shaped 

pattern from the .. island of Bermuda (fig. 396.1). 

Flight elevations ranged from 500 to 6,000 feet above 

sea. level, a.nd averaged about 3,000 feet. Navigation 
tf 

IlOOO Gammas 

foooGammas 

1000 Gammas I 

~~~r------------------------------------Sea level---------------------------------.~ 

65" BERMUDA 

FIGURE 396.1.-lndex map of region extending from Argentia, Newfoundland, to Puerto Rico, and three typical aeromagnetic profiles. Edge of continental 

shelf outlined by 100. and 1,000-fathom contours (broken and solid line, respectively) ; greatest ocean depths range from about 2,500 to 3,000 fathoms. 

Anomalous zone shown by shaded area around Bermuda. Profiles of total magnetic field are from an arbitrary datum. 

).· I 

I , 

tJ 

c1 

0 

0 

0 

t"'J 

0 

t"4 

0 

0 

H 

0 

> t"4 

Ul 

q 

:;:o 

< t"'J 

1-<j 

:;:o 

t"'J 

Ul 

t"'J 

> :;:o 

0 

~ 

...... 

tO 

0) 

...... 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 ·D-301 

errors of 10 miles are not unusmtl in these long overwaJer traverses. The regional magnetic gradients of 

the profiles are the effect of the earth's main magnetic 

.Held. Three distinct zones of sharply contrasting 

mn.gnetic patt:e111 are apparent over most of the area 

surveyed. A broad zone around Bermuda is characterized by numerous closely spaced anomalies of rather 

uniform size and has been shown on figure 1 by the 

shaded area. The anomalies in a second zone over the 

continental shelf and slope are variable in amplitude 

n.nd gradient and this zone is bounded by a fairly continuous 300- to 500-ga.mma anomaly which parallels the 

outer edge of the continental shelf. The third zone lies 

between the first two zones and is characterized by 

relatively smooth profiles. The distinctive zoning is 

not clearly defined east of Nassau where the smooth 

magnetic pattern disappears and is replaced by a less 

uniform profile. The very large steep-gradient 

anomaly in the middle of the Bermuda-Argentia profile 

(.fig. 396.1) is caused by one of a group of seamounts 

which extends to the northwest toward Cape Cod. 

Another of this group is crossed by the I-Ialifa,x profile. 

Even larger anomalies are associated with the island of 

Bermuda, indicating that Bermuda has a core of highly 

magnetic volcanic rocks (I(eller and others, 1954). 

Evidently the seamounts are also volcanic in origin. 

Depth analyses were made on all possible anomalies 

to learn something about their source. The method 

used is the measurement of the horizontal extent of the 

steepest gradient, which assumes that the anomaly is 

caused by large, vertical-sided masses of magnetic 

rock of semi-infinite downward extent. The accuracy 

of the values obtained from single profiles depends on 

whether the anomaly is two-dimensional, that is, 

elongated in the direction perpendicular to the profile. 

If not, the values obtained may be too large. In all, 

120 depth determinations were made. These fall into 

two groups. One group of 90 depths to magnetic rocks 

coincides with the Bermuda anomalous zone. The 

remaining 30 depth values are distributed over the con-

. tinenbtl shelf and slope, and a few are also in the region 

north of the "Test Indies where the magnetic zones w·ere 

not well developed. The lack of depth determinations 

in the intervening flat zone is expected because of the 

absence of usable magnetic anomalies. 

The depth values in the Bermuda zone indicate that 

magnetic rocks lie close to the ocean floor over the entire 

area. The change from the Bermuda anomalous zone 

to the flat magnetic zone is generally quite abrupt and 

well defined, but there is a short transition zone of small 

ripples on most of the profiles (section "B" on the Cape 

May profile, fig. 396.1). The two .most probable explanations of this transition zone are that the nearsurface mab'lletic rocks of the Bermuda zone have been 

downfaulted and buried. under relatively nonmagnetic 

sedimentary material, or that these rocks do not extend 

west of the boundary except for. a thin sheet or wedge. 

overlying rocks of low or very uniforn1 magnetic susceptibility. The first possibility was tested by taking 

a section of profile (section "A" on the Cape ~1ay profile) and projecting it upward mathematically to levels 

2 and 4 miles above the original level of observation 

(fig. 396.2). Section "B" does not sufficiently resemble 

section "A" even at the 4-mile level to support the 

possibility of clown-faulting. A measurement of the 

half-widths of some of the ripples in the transition zone 

gives an approxi1~a.te depth equal to the ocean depth, 

GAMMAS 

5oo L~ 

_ Aat2miles 

5oo f..________~- -- ------:-- A at 4 miles 

50:'-----f _---...,;;:;.,..8 --

0 25 50 MILES 

FIGURE 396.2.-Upward continuations of section "A" of Cape 

May profile compared with transition zone "B." 
D-302 GEOLOGICAL SURVEY RESEARCH 1 9 6 1 

which supports the second possibility, that of a thin 

sheet of magnetic rocks on the ocean floor. 

A comparison of the depths to magnetic rocks computed from anomalies over the continental shelf and 

slope was made with contoured values of the depth to 

the crystalline basement rocks determined principally 

from seismic. profiles by Lamont Geological Observatory 

(Drake and others, 1959). The depths were either in 

good agreement with (or greater than) the seismic 

values, which is normal for continental areas. Figure 

396.3 shows sections of each of the observed magnetic 

profiles across the continental shelf, and both seismic 

and magnetic depth values to basement rocks-the 

former depth values to rocks of higher seismic velocity, 

and the latter to rocks of higher magnetization. The 

fact that accurate depth analyses could be made from 

these basement anomalies indicates that the basic 

assumption of a basement composed of vertical-sided 

blocks of various magnetic susceptibilities is valid. 

The magnetic depth values which lie below the top of 

the crystalline rocks may indicate intrabasement 

magnetic rocks, departure from the necessary twodimensional conditions, or insufficient seismic information at the point of comparison. 

The anomaly which parallels the outer edge of the 

continental shelf is the most interesting single magnetic feature revealed by these profiles. Although its 

width and location are similar to a gravity anomaly 

observed by the Lamont group (W orzel and Shurbet, 

1955), the gravity anomaly may be accounted for by a 

combination of the increase in ocean depth off the edge 

of the shelf and a thinning of the continental crust from 

20 miles to an oceanic crust of 3 miles over a very short 

interval at the continental margin. Neither of these 

factors will produce the magnetic anomaly. The correlation of the magnetic and gravity anomalies is probably only fortuitous or indicates indirect control rather 

than a common source. The seismic data show a buried 

ridge of basement rocks at the outer edge of the continental shelf (fig. 396.3). The effect of this topogO'r---------------------~------.---------~--------~------------- ~----~------~--------

30,000LO. ~~.s . .. · •. ~~'"·' ·_··· --;=-----~·· ... ->· ·J 

0 50 100 MILES 

1

·1000 

Gammas 

L._ __ ___.JL...._ __ __...J 

0'.------------

30.J.~ . . . - "---] INC 

............ ~--

] r·················-·····-

······· ..... . 

FLA. 

FIGURE 396.3.-Sections of aeromagnetic profiles over the continental shelf and slope from Newfoundland and Nova Scotia 

to Florida, showing continental slope anomaly. Top of crystalline basement rocks from seismic data indicated by 

dots. Computed depths to magnetic rocks indicated by bars. 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-43.5 D-303 

500 Gammas 

Observed Computed 

NORTH SOUTH 

LONG ISLAND 

+ + + + 

10,000'- + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + 

20,000'- + + + + + + + + + + + + + + + + + + + + 

+ + + + + + + Probable crystalline rocks + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + 

30,000'-

+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + 

0 100,000 200,000 300,000 FEET 

F1ouum 396.4.-Computed and observed magnetic anomalies over basement ridge south of Long Island, N.Y. Section 

compiled from seismic data. 

raphy "·ns· computed for a profile south of Long Island, 

N.Y., where one of the Lamont seismic profiles is nearly 

coincident with one of the aeromagnetic profiles (fig. 

396.4). An arbitrary linear gradient was removed 

from the observed profile to facifitate the comparison 

with the computed anomaly. In order to give an anmna.ly "·.ith the amplitude of the observed anomaly, 

the rock must have an apparent Stlsceptibility of 

0.006 to 0.007 cgs units, which is high for continental 

basement rocks. The horizontal offset in position in 

this and other areas 1nay not be real because of locationaJ errors, but in general the magnetic anomalies are 

not highest where the ridge is highest and not lowest 

where the ridge is lowest. The success of the depth calculation technique here is evidence that the anomalies 

are caused by susceptibility contrasts in the crystalline 

basement rocks. The Lamont group has not detected 

any marked increase in seismic velocity associated with 

this basement ridge, but the recorded velocities are high 

eriough to include 1nost types of crystalline rocks. 

Therefore, we conclude that although basement topography undoubtedly contributes to the 1nagnetic profile 

it is not the sole cause of this large magnetic feature. 

The profile may be at least partly the expression of a 

large mass or series of masses of more magnetic rocks 

within the basement-possibly intrusive bodies along a 

zone parallel to the continental margin at the transition 

from a continental to an oceanic crust. 

REFERENCES 

Drake, C. L., Ewing, :Mauriee, and Sutton, G. H., 1!)59, Continenta 1 margins and geosynclines: the east coast of North 

America north of Cave Hatteras, 'in, Physics and chemistry 

of the earth: New York, Pergamon Press, '!-'· 3, v. 110-198. 

Keller, Fred, Meuschke, .J. L., and Alldredge, L. R., 1954, Aeromagnetic suneys in the Aleutian, Marshall, and Bermuda 

Islands: Am. Geophys. Union Trans., v. 35, No. 4, p. 558-

. 572. 

\Vorzel, .J. r.J., and Slmrbet, G. h, 1!.>55, Gravity anomalies at 

continental margins: TJ.S. Natl. Acad. Sci. Proc., v. 41, p. 

458-469. 
D-304 GEOLOGICAL SURVEY RESEARCH 19 61 

MINERALOGY, GEOCHEMISTRY, AND PETROLOGY 

397. COMPOSITION OF THE IRON-FORMATION OF DEVONIAN AGE IN THE CHRISTMAS QUADRANGLE, ARIZONA 

By RoNALD 'V'ILLDEN, ~{enlo Park, Calif. 

Six standard rock analyses and six semiquantitative 

Bpectrographic analyses of samples of the iron-formation in the Devonian Martin formation (Willden, 1960) 

in the Christmas quadrangle have recently been completed (table 397.1). The weighted average of four of 

these chemical analyses of samples taken at places 

where the total thickness of iron-formation i8: exposed 

shows that the bed contains 52.43 percent Fe20 3 and 

0.23 percent FeO. Other constituents average 8.62 percent CaO, 1.88 percent MgO, 6.48 percent C02, 16.90 

percent Si02, 5.49 percent Al20a, 1.75 percent P 205, 

0.16 percent .MnO, 0.23 percent Ti02, and 5.48 percent 

combined Na20, 1{20, H.20, and S. The chemical analTABLE 397.1.-Chemical analyses and semiquantitative spectrographic analyses of iron-formation in the Devonian Martin 

formation, Christmas quadrangle, Ariz., and one chemical 

analysis of "Rockwood" iron ore from Chamberlain, Tenn., for 

comparison 

[Chemical analyses of Christmas quadrangle samples by Paula M. Buschman and 

of 'l'ennessee sample by George Steiger (Burchard, 1913, p 76). Semiquantitative 

spectrographic analyses of samples 59W38, 59W39, and 59W40 by Paul R. Barnett, 

and of samples 59W92, 59W93, and 59W94 by Nancy M. Conklin. For location 

of samples see Willden, 1960, fig. 11.1, where samples 1, 4, and 5 correspond to 

samples 59W38, 59W39, and 59W40 respectively of this study and samples 2, 6, 

and 7 correspond to samples 59W92, 59\V94, and 59W93 respectively of this study] 

Constituents in samples, identified by laboratory and field number "Rockwood" 

I I I I 

iron 

F2726 ~ F2727 F2728 02892 02893 02894 ore 59W38 59W39 59W40 59W92 59W93 59W94 

Chemical analyses 

Si02------------ 13.60 19.08 16.54 30.82 14.73 19.64 7. 92 

Ah03------------ 5. 17 4. 45 3. 58 10.33 6.02 6. 30 3. 07 Fe203 ___________ 55.56 55.48 50.11 43.13 47.57 49.04 50.60 Feo ____________ . 23 .18 .26 . 45 .19 . 45 2.44 MgO ___________ 1.49 2.05 3. 74 1. 01 2. 20 2.40 1.71 cao ____________ 10.26 7.14 10.16 2.16 9. 96 7. 79 13.77 

Na20. ---------- .07 .07 .10 .07 .10 .14 .10 

.K20------------ 1. 22 1. 05 . 90 . 2.36 1. 67 1. 69 . 25 H20+ ____________ 1.88 1. 87 1. 93 4. 78 6. 35 2. ·18 5. 52 H2o- ___________ . 80 . 67 .43 2.05 . 60 . 95 . 59 

1'i02------------ . 22 .20 .16 . 34 . 25 . 28 .10 

P205------------ 1. 80 1. 41 1. 21 1. 34 2. 18 1. 80 1. 31 MnO ___________ . 14 .15 .17 . 21 . 20 .16 1. 33 

C02----.. --------. 7. 36 6.02 10.52 .10 7. 31 6.30 12.29 803 _____________ .00 .00 .00 .00 .00 .00 (2) 

s . -------------- . 03 .03 . 03 .02 .03 . 03 .050 

------------------------ SubtotaL. 99.83 99.85 99.84 99.17 99.36 99.45 100.05 

Less 0 ____ .02 .02 .02 . 01 . 02 .02 

---------------------- TotaL ____ 99.81 99.83 99.82 99.16 99.34 99.43 

See footnotes at end of tab.Ie. 

TABLE 397.1-Continued 

Constituents in samples, identified by laboratory and 

F2726 

59W38 

Ba ______________ 

Be ______________ 

Ce ______ ----- ___ Co ______________ 

Cr.-------------

Cu ______________ 

Ga ______________ 

La ______________ 

Mo _____________ 

Nb. ------------

Nd------------- NL _____________ 

Pb ______________ 

Sc. -------------

Sr ---------------

v--------------- y _______________ 

Yb ______________ 

Zr_ _________ -----

1 Reported as Mn. 

2 Not reported. 

0.007 

0 

.03 

.0015 

.007 

.0007 

.0007 

. 015 

0 

. 0015 

. 015 

. 0015 

.0015 

.0007 

.03 

. 015 

.003 

.0007 

.003 

I 

field number 

F2727 

I 

F2728 

I 

02892 

I 

02893 

I 

02894 

59W39 59W40 59W92 59W93 59W94 

Spectrographic analyses a 

0.007 0.003 0.03 o. 015 0.007 

0 0 .0003 .0003 . 00015 

.03 .03 .03 .03 . 03 

. 0015 .0015 .003 .003 .003 

.007 .007 .007 .007 .007 

.0003 .0003 .0015 .0007 . 0015 

.-0007 .0007 . 0007 .0003 .0007 

. 015 .007 .015 . 015 . 015 

0 0 <.005 <.005 <.005 

.0015 . 0015 .0015 . 0015 .0015 

. 015 . 015 .015 .015 . 015 

. 0015 . 0015 .003 .003 .003 

. 0015 .0015 .003 .003 .003 

.0007 . 0007 . 0015 .0015 . 0015 

.03 .03 .03 . 03 .03 

. OJ5 .007 .03 .03 .03 

. 003 .003 .007 . 007 .007 

. 0007 .0007 .0007 .0007 .0007 

.007 .007 .015 .007 .007 

3 Figures are reported to the nearest number in the series 7, 3, 1.5, 0.7, 0.3, 0.15, 

etc., in percent. These numbers represent midpoints of group data on a geometric 

scale. Comparisons of this type of semiquantitative results with data obtained by 

quantitative methods, either chemical or spectrographic, show that the assigned 

group includes the quantitative value about 60 percent of the time. Also looked 

for but not found: Ag, As, Au, Bi, Cd, Dy, Er, Eu, Gd, Ge, Hf, Hg, Ho, In, Ir, 

Li, Lu, Os, Pd, Pr, Pt, Re, Rh, Ru, Sb, Sn, Sm, Ta, Tb, 're, 'l'h, '1'1, 'l'm, U, ,V, 

and Zn. 

yses of the iron-formation in the . Christmas quadrangle closely resem.ble an analysis of a semi-hard 

Clinton iron ore fron1. Chamberlain, Tenn. (Burchard, 

.1913, p. 76), shown in the last column o-f table 397.1. 

The Clinton hard and semi-hard ores contain less silica 

and alumina and more carbonates than the iron-formation in the Martin, but the total iron content of the t-wo 

formations is about the same. In comparison, the 

oolitic iron deposits in the Bliss sandstone of Cambrian and Ordovician age in south western New ~1exico 

contain 20.8 to 39.2 percent iron, 0.13 to 0.66 percent 

phosphorus, 0.95 to 3.3 percent lime, and 27.0 to 62.8 

percent silica (l{elley, 1951, p. 2207). 

The chamosite previously reported (vVillden, 1960) is 

more probably the mineral glauconite which occurs as 

ooliths both with and without interlayers of hematite, 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 D-305 

FIGURE 397.1.-Photomicrograph of glauconite-hematite ooliths 

in detritus-rich part of the iron-formation of the l\Iartin 

formation, Christmas quadrangle, Arizona. Detrital material 

consists of silt-size quartz and carbonates. Cross-polarized 

light. 

and is most abundant in parts of the bed with a high 

proportion of detrital material (fig. 397.1). The 

glauconite is believed to be a well-ordered type (Burst, 

1958) because X-ray diffraction patterns of the detritusrich parts of the iron-formation show well-defined 

10 A (angstrom) and 5 A lines (the 3.3 A line is 

masked by the strong quartz line at 3.35 A). The relative intensities of the diffraction lines indicated the 

glauconite amounts to several percent of the detritusrich rocks. No siderite has been identified in either 

thin sections or X-ray patterns. The shift of about 

0.2° toward a lower 2-0 value of the characteristic 

dolomite lines may be due to substitution of manganese 

or possibly iron in the dolomite lattice. 

The iron-formation contains a much greater amotmt 

of the lanthanides than normal sedimentary rocks or 

other common rocks of the upper lithosphere (table 

397.2). However, scandium and yttrium, which are 

commonly associated with the lanthanides, occur in 

about the same amounts in the iron-formation as they 

do in the upper lithosphere. 

The manner of occurrence of the lanthanides in the 

iron-formation is as yet unknown because the extremely fine grained hematite, which is intimately 

intergrown with the other minerals in the rocks, has 

greatly hampered efforts to obtain clean mineral separates for analytical work The iron-formation in the 

Christmas quadrangle contains considerable apatite 

and it is quite possible the apatite carries the lanthanides and scandium and yttrium. This may not be 

the entire explanation, however, as is indicated by the 

average content of lanthanides in phosphorites of the 

Phosphoria. formation (Gulbrandsen, 1960) shown in 

table 397.2. The phosphorites contain more than 12 

times as much apatite as the iron-formn,tion and yet 

the phosphorites show only a two-fold io.crease in the 

amount of lanthanum and neodymium over the ironformation, and the phosphorites contain no cerium. 

The phosphorites also differ in containing ten times as 

much yttrium as the iron-formation. 

TABLE 397.2.-Distribution of scandium, yttrium, and some lanthanides in iron-formation of Devonian age, Christmas quadrangle, Ariz., 

in phosphorites of the Phosphoria formation (Permian), in sedimentary iron ores, in some rocks of the lithosphere, and in silicate 

meteorites 

[Leaders indicate value not reported] 

Grams per ton Material 

Sc y La Ce Pr Nd Yb 

Silicate meteorites (N oddack, 1935) ____________ 5. 8 6. 13 2. 05 2. 30 0. 97 3. 37 1. 85 

Basic rocks-basalts, gabbro, norites, diabases, 

and others (Vinogradov, 1956) ____ _________ 24 18 27 ""10 1.3 "'10 1 

Acidic rocks-granites, liparites, rhyolites, and 

others (Vinogradov, 1956) ______ ___________ 7 20 46 60 10 40 2 

Sedimentary rocks-shales and clays (Vinogradov, 1956) ____________________________ 10 33 40 30 5 18 2. 2 

Sedimentary iron ores (Goldschmidt and Peters, 

1931) ------------------------------ - -- -- 6. 5-65 8-79 --- ------- - --------- ---------- ---------- ---------- Average of 60 samples of phosphorite of Phosphoria formation in Idaho (Gulbrandsen, 

1960) ----- ------------ ------------------ 10 300 300 ---------- ---------- 300 10 

Iron-formation of Devonian age, Christmas 

quadrangle, Ariz __________________________ 7 30 150 300 (') 150 7 

' Looked for but not found. 
D-306 GEOLOGICAL SURVEY RESEARCH 19 61 

REFERENCES 

Burchard, E. F., 1913, The red iron ores of east Tennessee : 

Tennessee Geol. Survey Bull. 16, 173 v. 

Burst, J. F., 1958, Mineral heterogeneity in "glauconite" pellets: 

Am. Mineralogist, v. 43, p. 481-497, 

Goldschmidt, V. M., and Peters, 1., 1931, Zur Geochemie des 

Scandiums: Nachr. Ges. Wiss. GOttingen, Math-physik. 

Klasse, III; pt. iv, p. 257-279. 

Gulbrandsen, R. A., 1960, Minor elements in phosphorites of the 

Phosphoria formation [abs.] : Geol. Soc. America Bull., v. 

71, p. 1876. 

Kelley, V. 0., 1951, Oolitic iron deposits of New Mexico: Am. 

Assoc. Petroleum Geologists Bull., v. 35, p. 2199-2228. 

Noddack, Ida, 1935, Die Hiiufigkeiten der seltenen Erden in 

Meteoriten: Zeitschrift anorg. allgem. Chem. 225, p. 337-

364. 

Vinogradov, A. P., 1956, The regularity of distribution of chemical elements in the earth's crust: Akademiya Naul\: 

SSSR, Geokhimiya. 1956, ( 1), p. 1-52 (translation by Mme. 

S. Botcharsky, in Great Britain Atomic Energy Research 

Est. lib. trans. 795). 

Willden, Ronald, 1960, Sedimentary iron-formation in the 

Devonian Martin formation, Christmas -quadrangle, 

Arizona, in Short papers in the geological sciences: U.S. 

Geol. Survey Prof. Paper 400--B, p. B21-B23. 

398. CHEMICAL ANALYSES OF BRINES AND CRUDE OIL, CYMRIC FIELD, KERN COUNTY, CALIFORNIA 

By E. H. BAILEY, P. D. SNAVELY, JR., and D. E. WHITE, Menlo Park, Calif. 

Connate waters and crude oil have been suspected as 

possible transporting agents of metals of a wide variety 

of mineral deposits, including lead-zinc deposits of the 

Mississippi Valley type (White, 1958), and possibly 

some quicksilver and uranium deposits (White, 1955, 

1960; Erickson, Myers, and Horr, 1954, p. 2217). 

Chemical analyses of liquid hydrocarbons and associated brines were therefore obtained from the Cymric 

field, where Stockman (1947, p. 37) had reported mercury in the crude oil; particular attention was given to 

the minor metal contents. 

We are indebted to the Honolulu Oil Corporation for 

permission to publish these data, and are particularly 

grateful to the late Mr. F. M. Cole of the Honolulu Oil 

Corporation for supplying information and making 

arrangements for us to collect samples of brine and 

crude oil from the Cymric field. 

GEOLOGIC SETTING 

The Cymric oil field is near the southwestern margin 

of the San Joaquin Valley synclinorium, which contains 

some of the most productive oil fields in California (fig. 

398.1). The field is of particular geologic interest because it produces oil from 11 separate zones that range 

in age from Eocene to Pleistocene (McMasters, 1948). 

The strata penetrated by wells have a maximum composite thickness of more than 8,500 feet, and consist predominantly of shale and siltstone with interbedded 

sandstone and silty sandstone. A major unconformity 

separates the Pliocene strata from the Miocene strata, 

and lesser unconformities occur in the Pliocene .sequence and within and at the base of the Miocene rocks. 

The principal structure in the field is a narrow northwest-trending anticline which involves only Miocene 

and older strata; younger strata are essentially monoclinal across the fold. Along the northeast flank of the 

R. 20 E. R. 21 E. R. 22 E. 

FIGURE 398.1.-Map showing location of Cymric oil field, California. Outlines of oil fields taken from California Division 

of Oil and Gas, Regional Wildcat Map 4-1, November 1955. 
SHOH'l' PAPEHS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-43.5 D-307 

anticline the pre-Pliocene beds are faulted down to the 

northeast, but the faults do not extend up into the Pliocene rocks (Pierce, 1947, p. 10; ~1cM:asters, 1948, p. 44). 

The pr.inci pal controls for the accumulation of oil in 

the pre-Pliocene rocks are anticlinal closure and fault 

traps. In the monoclinal Pliocene and Pleistocene 

strata, favorable sites for oil accumulation result from 

pinch-outs n.nd lateral changes in the permeability of 

sandstone beds (~1c~1asters, 1948, p. 44). 

METAL CONTENTS OF CRUDE OIL 

Quantitative spectrographic analyses of metal contents were made on the ash from three samples of the 

Cymric field crude oil (tables 398.1 and 398.2). The 

crudes contain a significant quantity of mercury but 

lack detectable concentrations of gallium and large 

·amounts of nickel found elsewhere in San Joaquin Valley crude o.ils (liyclen, 1958, p. 95-96). Other chara.cter.istics of the ash of California crude oils, outside 

the Cymric field, a.re relatively high content of cobalt, 

deficiency of manganese and vanadium, and zinc in 

qun.nt:it:ies below the limits of spectographic determinations (l[yclen, 1958, p. 95-96 and table 9). 

The occurrence of mercury :in the Cymric oil field is of 

unusual interest because of a possible genetic relation 

between mercury deposits and connate water or crude 

oil. Liquid nncl solid hychocarbons are common in the 

ores o:f many California mercury mines (Averitt, 19·45, 

p. 78; Bailey, 1946, p. 217; Yates and Hilpert, 1946, p. 

248) . In some mines, such as the Abbott mine in Lake 

County, methane gas is escaping in amounts large 

e~10ugh to require extra precautions against explosions. 

TAUI~Jn 398.1.-Quantitative spectrographic analvses of ash from 

petroleum of Cymric oil field, Calif. 

[Analyst, Nancy Conklin; samples collcctcd May 29, 1959.) 

22-255 1 

Producing zone __________ Phacoides 

Age ____________________ Early 

Miocene. 

Ash, in percellt_ _________ 1. 93 

AnnJysis of ash, in percent: 4 

Cu ________________ . 001 Ni _________________ . 012 

Fe ________________ .. . 01 v __________________ . 004 

I Well location, ncar center sec. 22, T. 29 S., R. 21 E. 2 Well location, SEY.SWH sec. 22, T. 29 S., R. 21 E. 3 Wolllocatlon, NWMSE}~ soc.' 22, T. 29 S., R. 21 E. 

Well 

22-147 2 22-256 3 

Oceanic Point of 

Rocks 

Oligo- Late 

cene. Eocene. 

1. 70 1. 22 

. 001 . 001 

. 012 .. 009 

. 01 . 01 

. 006 . 005 

• Looked for but not found: Mn, Zn, Mo, Ga, Pb, U, Or, Co. Tho results have 

an overall accuracy of ±15 percent of quantity reported except that they are less 

nccumtc nom· limits of detection, where only one digit is reported. 

TABLE 398.2.-1\fetal contents of petroleum of Cymric oil field, 

Calif. 

[Samples collected June 14, 1955) 

Well 

22-255 22-147 22-256 

Producing zone ____ . ______ Phacoides Oceanic Point of 

Rocks 

Analysis, parts per million: 

CuI __ . ______________ 0. 2 0. 2 0. 2 

Nil ________________ 2. 3 2. 0 1. 1 

Fe1 ________________ 2 2 2 

VI- - - - - - - - - - - - - - - - - 8 1.0 .6 

Hg2---------------- 2. 6 and 2. 4 ---------- 21 and 14 

Hg3---------------- 1.!) ---------- 2. 9 

1 Computed from quantitative spectrographic analyses of ash given in table 398.1. 2 Determined by J. D. Pera, Buckman Laboratories, Memphis, Tenn. 

3 Determined by C. A. Horr, U.S. Geological Survey. 

The quantity of hydrocarbons in the ores is highly variable and difficult to assess, but is considerably larger 

than is generally realized. In the Abbott mine, hydrocarbons are probably more abundant than cinnabar, 

and even in the New Almaden mine in Santa Clara 

County, hydrocarbons may have approached cinnabar 

in abundance. At the Two-forty-eight mine in· the 

Terlingua district, Texas, oil and tar were locally so 

abundant that in furnacing the ore it was at times necessary to turn off the burners and exercise other precautions to prevent the self-fueled ore from damaging 

the furnace by overheating (R. G. Yates, oral communication, 1961). 

A close time relation between the deposition of mercury minerals and hydrocarbons in quicksilver deposits 

is generally indicated by the paragenetic sequence, and 

an equally close spatial relationship also generally 

exists. In mercury deposits of California Bailey (1959) 

found veins composed of many small oil-filled siliceousshelled spheres, and he interpreted the spheres as 

formed around oil droplets suspended in a hydrous 

fluid. Cinnabar occurs in the siliceous shells, indicating 

that either the hydrous fluid or the immiscible oil droplet was an ore-bearing fluid. 

It is interesting that the Cymric field is on the southeast prolongation of the main mercury belt east of the 

San Andreas fault; and, further, that :its distance of 

about 45 miles south of the Pa.rkfield mercury district 

is but a little more than the average distance of about 

35 miles that separates the other districts along this 

ore belt. 

CHEMICAL COMPOSITION OF THE BRINES 

The oil field brines are of particular interest because 

of their metal contents and because thermal waters 
D-308 GEOLOGICAL SURVEY RESEARCH 19 61 

TABLE 398.3.-Mercury content of petroleum and brine from 

Cymric oil field, Calif. 

[Samples collected June 14, 1955; asterisk indicates not sufficient oil for analysis] 

22-255 

Producing zone _________ _ Phacoides 

Hg content, oil layer,1 

parts per million _____ _ 2. 6 

Do., duplicate 1 _____ _ 2. 4 

Do., duplicate 2 _____ _ 1.9 

Hg content, water layer,1 

parts per million _____ _ . 098 

Do., duplicate 1 ____ _ 3 • 18 

Sediment content in 

water,1 parts per million__________________ 64 

Do., duplicate 1 ________________ _ 

Hg content of sediment, 

percent 1- __ - ___ - _---- . 04 7 

Do., duplicate 1 ________________ _ 

Additional Hg in water if 

sediment originally dissolved,1 parts per million__________________ . 03 

Do., duplicate 1 ________________ _ 

Average Hg in water 

when analyzed, parts 

per million____________ . 14 

Average original Hg in 

water if sediment dissolved, parts per million _________________ _ . 17 

Well 

22-166 

Oceanic 

(*) 

(*) 

(*) 

3 0. 12 

78 

128 

. 087 

. 36 

. 31 

. 28 

. 40 

. 10 

. 44 

I Analyst, J. D. Pera, Buckman· Laboratories, Inc., Memphis, Tenn. 

2 Analyst, C. A. Horr, U.S. Geological Survey. 

22-256 

Point of 

Rocks 

21 

14 

2. 9 

270 

180 

. 22 

. 048 

. 14 

. 13 

. 38 

. 23 

. 14 

. 45 

a Fred Ward, of the Geological Survey, searched for Hg in remaining parts of these 

same samples in February 1961, and reported less than O.C2 ppm ofHg and As in each, 

0.03 ppm of Sb in 22-255, and 0.01 ppm of Sb in 22-166. 

chemically similar to oil field brines are associated elsewhere with quicksilver deposits (White, 1960, p. 453; 

and unpublished data). The analyses in tables 398.3-

398.5 are more detailed than others that have been 

published. 

Of additional interest are progressive changes in composition with increasing depth and age of the probable 

source rocks. Although dependable generalizations 

cannot be drawn from three analyses, this series suggests that the following components or ratios increase 

downward: Ca, I, evaporated residue, Ca/N a, and possibly Ba, Li, NH4, Cl, and Br. The components or 

ratios that decrease downward are: Si02 , AI, Mg, I{, 

HCOa, F, and the ratios of Mg/Ca, HC03/Cl, F /Cl, and 

possibly Br;/CJ and B/Cl. These changes are consistent 

with trends pointed out by White (1957, 1960): With 

increasing age, oil field brines are inclined to be higher 

in salinity and to change from N aCI to N a-Ca-Cl type. 

In line with these trends, most brines of deep Tertiary 

oil fields are high in N a and CI, but Ca is generally less 

than 10 percent of the N a; deep brines of most preTertiary oil fields throughout the world, however, are 

of the N a-Ca-Cl type, with calcium exceeding 10 percent of the sodium, and with total -salinities commonly 

far higher than that of sea water. We are not a ware 

that changes in these chemical types with depth have 

been so clearly demonstrated in the same field. The 

chemical differences in the Cymric analyses almost certainly do not reflect comparable differences in composition of sea water during different parts of the 

Tertiary but are believed to result from diagenetic 

changes and reactions between sediments, organic matter, and interstitial water. Additional modifying 

effects probably also result from the fine-grained sediments behaving as semipermeable membranes (De-. 

Sitter, 1947, p. 2039; White, 1957, p. 1667) that permit 

selective diffusion of water and certain other components, a.nd selective retention of calcium and chloride . 

Concentrations of minor metals in the waters are not 

clearly related to 1netal concentrations of associated 

crude oils (tables 398.1 and 398.5). Reported contents 

of some components determined by wet methods (table 

398.4) and by spectrographic methods (table 39'8.5) are 

TABLE 398.4.-Chemical analyses of waters from Cymric oil 

field, Calif. 

[Analyst, C. E. Roberson; sample collected June 14, 1955] 

Depth of production, feet_ _______ _ 

Producing wne __________________ _ 

Temperature, degrees centigrade .. 

pH_------------------------------

Chemical analysis, parts per 

million: 

8102--------------- __ · __ ------- AL_ ----- _____ ------- ________ _ 

Fe 1 __ ------------------------

Mn __________________________ _ 

As ____________ ------------_---

Cu. __________ --- __ --------- __ 

Pb. ________ ------------------

zn ____ ------------------------ Ca ___________________________ _ 

Mg ___ ------------------------ Ba _____________ ---------- ____ _ 

Na _____________ --------------

K.---------------------------

LL ____ -- ___ ------------------

NH•--- _________ -------------- Hg 2 _________________________ _ 

HC03.- ----------------------

C03. _ -----------------------.-

804 ____ -----------------------

8203-------------------------- CL __________________________ _ 

F-----------------------------

Br ___________ -----------------

L----------------------------

N02-------------------------- NOa _________________________ _ 

See footnotes at end of table. 

22-255 

3, 000± 

Phacoides 

49± 

7.1 

52 

.9 

6. 4 

.3 

.00 

.00 

.00 

.06 

325 

123 

7. 2 

6,150 

136 

4. 9 

45 

.14 

666 

0 

4.1 

2.4 

9,940 

3.6 

35 

20 

.15 

0 

Well 

22-166 

4, 950 

Oceanic 

81 

7. 5 

47 

.4 

1.2 

.08 

.0 

----------------

----------------

---------------- 373 

115 

7.1 

5,820 

132 

4.3 

51 

.10 

535 

0 

1.6 

Not det'd. 

9,840 

3. 4 

30 

23 

.00 

3 

22-256 

5, 320 

Point of Rocks 

81.4 

7. 2 

14 

.2 

61 

2.0 

.00 

.00 

.02 

. 40 

3,040 

49 

8. 7 

6, 710 

113 

9. 9 

51 

. 14 

287 

0 

31 

3.3 

15,300 

2.0 

46 

29 

.08 

0 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-4.3.5 D-309 

TABLE 398.4.-Continu.ed 

Chemical analysis, parts per 

million-Continued 

PO•··············--·---·-··--

B •••• ·-······ .•• --. ·--·-·--··· 

:H2S. ····················-----

1'otal, ns reported •••...•••• 

J~vnporntcd residue, nt 180° C, 

parts per million _______________ _ 

Specific conductance, mlcrohms, 

25° 0.----- --~- ----------------- Specific gmvlty nt 20° C •••••••.•. 

Rntlos by weight: 

Ca/Nn ••••••••••• _____ • __ -----

Mg/Cn •• --------------------- K/Na ___________ . _ ---~------ __ 

LI/Na •••• -----.-------------. N.H•/Nn ••.•••.•.•.•.•...•.••. 

H COs/CL -------------------- SO•/CI ••••••••••• _ ••.••• _ ••••. 

F/CL ••• ---·-··········--··--- Br/CL •••.•• ____ ••• -----------

1/CL ••• ----••. ------- ___ •• ---

B/CL •••••••.••• ---- _ ----••••. 

t In solution when mwlyzcd. 

2 Sec table 3118.3. 

Well 

22-255 22-166 

0. 2 -------------- 142 140 

0 0 

17,700 17, 100 

17,800 18,600 

25,200 25,800 

1.009 1.009 

.053 .064 

'38 '31 

.022 .023 

.00080 .!l0074 

.0073 .0088 

.067 .054 

'00041 '00016 

.00036 .00034 

'0035 .0030 

.002G .0023 

'014 '014 

22-256 

0. 2 

146 

0 

25,900 

28,500 

31,800 

1. 016 

'45 

.016 

.017 

.0015 

.0076 

'019 

. 0020 

'00013 

.0030 

.0019 

. 0095 

TABLE 398.5.-Spectrographic analyses of evaporated resid1tes of 

waters from Cyrnric oil field, Calif. 

[Analyst, N. B. Sheffey; samples collected June 14, 1955] 

Well 

22-255 22-166 22-256 

Producing zone __________ Phacoides Oceanic Point of 

Rocks plf ____________________ 7. 1 7. 5 7. 2 

Analysis, pal'ts per 

million: 1 

Cu ________________ 4. 8 . 04 1 Ag _________________ 02 <. 02 . 03 Pb _________________ 2. 3 <. 2 <. 3 l\1n ________________ 25 2 1. 4 Fe _________________ 29 15 14 Or _________________ 4 <. 04 ·<. 06 Al _________________ 43 2 3 Ti _________________ 2. 0 <. 04 <. 06 

Z~"----------------- 5 <. 2 <. 3 81' _________________ 21 82 66 Ba _________________ 2. 9 7 5. 4 Li _________________ ------------ 2. 6 ---------- llb ________________ ------------ 2 ----------

t Looked for but not found: Mo, <0.2 ppm; W, <4; Go, <0.2; Co, <0.2; Ni, <0.2; 

V, <0.2; Oa, <0.06; Cs, <0.6; Be, <0.02; As, <10; Cd, <1; Sb, <2; Sn, <0.2; Y, 

<0.2; Yb, <0.02; Zn, <4. 

not in close agreement; all of the data are included 

without knowledge of actual quantities present when 

the samples were analyzed. In addition, the differences 

in reported mercury contents of the waters indicate that 

mercury is not yet certain to be in the waters ; however, 

the reported presence of mercury in the crude oils has 

been confirmed definitely. Unusually high metal concentrations reported in the brine from well 22-255 

are of additional interest. This brine was · nearly 

neutral in pH but apparently contained very high contents of Fe, Cu, Ph, and some other elements. Further 

careful search for n1inor elements in crude oils and 

brines is clearly needed. 

REFERENCES 

Averitt, Paul, 1945, Quicksilver deposits of the Knoxville district, Napa, Yolo, and Lake Counties, California: California 

Div. Mines, 41st Rept. of State Mineralogist, chap, 2, p . 

65-89. 

Bailey, E. H., 1946, Quicksilver deposits of the western Mayacmas. district, Sonoma County, California: California Div . 

Mines, 42d Rept. of State Mineralogist, chap. 3, p. 199-230. 

---1959, Froth veins, formed by immiscible hydrothermal 

fluids, in mercury deposits, California : Geol. Soc. America 

!Bull., v. 70, p. 661-664. 

DeSitter, L. U., 1947, Diagenesis of oil-field brines: .A.m. Assoc. 

Petroleum Geologists Bull., v. 31, p. 2030-2040. 

Erickson, R. L., Myers, A. T., and Horr, C . .A.., 1954, Association 

of uranium and other metals with crude oil, asphalt, and 

petroliferous rock : Am. Assoc. Petroleum Geologists Bull., 

v.28,p.2200-2218. 

Hyden, H. J., 1958, Uranium and other metals in crude oils: 

U.S. Geol. Survey open-file report, 124 p. 

McMasters, J. H., 1948, Cymric oil field, Kern County, California, 

in Structure of typical American oil fields-a symposium: 

Am. Assoc. Petroleum Geologists Spec. Pub., v. 3, p. 38-57. 

Pierce, G. G., 1947, Cymric oil field, Kern County, California: 

California Div .. Oil and Gas, v. 33, no. 2, p. 7-15. 

Stockman, L. P., 1947, Mercury in three wells at Cymric: Petroleum ·world, Feb., p. 37. 

White, D. E., 1955, Thermal springs and epithermal ore deposits : 

Econ. Geology, 50th Anniv. vol., p. 99-154. 

---1957, Magmatic, connate, and metamorphic waters: Geol. 

Soc. America Bull., v. 68, p. 1659-1682. 

--- 1958, Liquid of inclusions in sulfides from Tri-State is 

probably connate in origin [abs.]: Geol. Soc. America Bull., 

v.69,p. 1660-1661. 

--- 1960, Summary of chemical characteristics of some waters 

of deep origin, in Short papers in the geological sciences: 

U.S. Geol. Survey Prof. Paper 400-B, p. B452-B454. 

Yates, R. G., and Hilpert, L. S., 1946, Quicksilver deposits of 

eastern Mayacmas district, Lake an~ Napa Counties, California: California Div. Mines, 42d Rept. of State Mineralogist, chap. 3, p. 231-286. 
D-310 GEOLOGLCAL SURVEY RESEARCH 1 9 6 1 

399. SPHENE IN GRANITIC GNEISSES OF SOUTHEASTERN CONNECTICUT 

By RICHARD GoLDSMITH, GEORGE L. SNYDER, and NANCY M. CoNKLIN, Denver, Colo. 

Work done in cooperation with the Connecticut Geological and Natural History Survey 

During mineral separations of rocks from southeastern Connecticut,. it was noted that the accessory sphene 

from some of the rocks showed unusually high magnetic 

susceptibility as compared to sphene from other rocks 

in the area (tables 399.1, 399.2). 

The formula for sphene according to Sahama ( 1946) 

is OaTiSi02 ( 0, OH, F). Calcium may be replaced by 

N a, rare earths, Mn, Sr, or Ba. Titanium may be replaced by AI, Fe+3

, Fe+2 , Mg, Nb, Ta, V, or Cr; and 

TABLE 399.1.-Analyses, in percent, of sphene in gneisses from 

southeastern Connecticut 

[Analyst, N. M. Conklin] 

Sample 1 

2 

Semiquantitative spectrographic analysis 2 Analysis computed from 

chemical analysis 

SL-------------- 7. 0 >10.0 

AL--------------- . 7 3.0 

Fe. __ ------------ 3. 0 1.5 

Ca.-------------- >10. 0 >10.0 TL ______________ >10.0 >10.0 Mg_______________ . 07 .03 

Mn. _ ------------ . 7 .3 

Ba. -------------- . 007 .003 

Be. __ ------------ trace trace 

Ce. _ ------------- 1. 5 .3 

Cr ___ ------------ . 0 .0015 

Cu_______________ . 003 . 0003 

Dy --------------- . 3 .3 

Er ___ ------------ . 15 . 07 Eu_______________ . 07 .03 

Qd_______________ . 3 .15 

Ho_______________ . 07 .03 

La_______________ . 7 .07 Lu_______________ . 015 .007 

Nb_______________ . 3 .15 

Nd_______________ l. 5 . 7 

Pb--------------- . 007 . 003 

Pr________________ . 3 .0 

Sc________________ . 0 .0 

Sn. __ . ----------- . 3 . 03 

Sr________________ . 03 .007 

Sm_______________ . 7 .15 

Tb.----~--------- . 03 . 015 Tm______________ .03 . 015 v ________________ -------- . 015 

Y ---------------- 1. 5 .7 

Yb_______________ .15 .07 

Zr ---------------- 1. 5 .7 

Cerium group____ 4. 8 1.3 

Yttrium group___ 2. 5 1.4 

See footnotes at end of table. 

>10.0 

1.5 

. 7 

>10.0 

>10.0 

. 03 

.15 

.003 

.0 

.0 

.007 

.003 

.07 

.03 

.0 

. 015 

.015 

.0 

.007 

.15 

.0 

.0 

.0 

.007 

. 07 

. 003 

.0 

.0 

.007 

.07 

.7 

.07 

.07 

.0 

.9 

>10.0 

1.5 

.3 

>10.0 

>10.0 

.015 

.15 

.003 

.0 

.0 

14.0 

3. 8 

4.4 

16:0 

18.4 

14.2 

.0 

. 1 

20.5 

24.6 

14.2 14. G 

2. 3 .5 

<.1 1.7 

20.2 18.4 

20.1 21.2 

. 007 ----------- ------ ----- -----

.0007 ----------- ------ ----- -----

.0 ----------- ------ ----- -----

.0 

.0 

trace 

.0 

.0 

.0 

.015 

.0 

.0 

.0 

.0 

. 005 

. 007 

.0 

.0 

.0 

.03 

. 03 ----------- ------ ----- -----

.003 

.0 

. 0 } .03 . 3.1 trace . 2 3. 7 

TABLE 399.1.-Continued 

Sample 1 

2 3 4 

Optical properties 

nx .. -------------. 1. 900 

31° 

1. 885 1. 880 1. 895 1. 843 1. 901 1. 84 1. 90 

2V __ -------------

! Sample localities: 1, From aegirine-augite granitic gneiss, Flat Rock quarry, ~ 

mile west of Cohanzie school, W side Connecticut Route 82, Waterford, Conn., 

Montville quadrangle; Frantz isodynamic separator setting, 0.65 amps; 20° forward, 

15° sideward tilt. 2, From hornblende-bearing granitic gneiss, road cut, Connecticut Route 163, ~ mile north of Connecticut Route 82, Fitch ville quadrangle; Frailtz 

isodynamic separator setting, 0.85 amps; 20° forward, 15° sideward tilt. 3, From biotite-muscovite quartz-monzonitic gneiss, Canterbury gneiss, southwest side of Hearth· 

stone Hill, northwest comer of Norwich quadrangle; ·Frantz isodynamic separator 

setting, 1.35 amps; 20° forward, 15° sideward tilt. 4, From plagioclase gneiss, near 

junction of Cook's Hill road with Connecticut Route 87, cast-central part of Columbia 

quadrangle; Frantz isodynamic separator setting, 1.5 amps; 20° forward, 15° sideward 

tilt. 5, Keilhauite from Rhode Island (Young, 1938, p. 151). 6 and 7, Sphene and 

"grothite" from Finland (Sahama, 1946, p. 96, 98). 8, Keilhauite from Abyssinia 

(Morgante, 1943). 

2 Generally reported to nearest number in the series 7, 3, 1.5, .7, .3, and so forth. 

TABLE 399.2.-Percentage of sphene and rare-earth-bearing accessory minerals by modal analyses, and rare-earth content of total 

rock by semiquantitative spectrographic analyses, of gneisses of 

southeastern Connecticut 

[Analysts, N. M. Conklin and Paul R. Barnett} 

Sample 1 

2 3 4 

--------------1---------------

Accessory minerals: 

Sphene _________ ------ ___ ------------

Allanite ____________ --- ______ --------

0.2 trace 0 

0 trace 0 

0.1 o. 2 

trace <. i 

Monazite _______________ ----_-------- 0? 0 0 0 <.1 

Aegirine-augite 2 ____________________ _ 4. 3 0 0 0 0 

Rare earth content: Cerium group ______________________ _ .04 .03 .00 .00 .03 

Yttrium grouP---------------------- . 016 .004 .002 .002 .002 

1 Samples 1, 2, and 3, same as in table 1, analyses by point count; 4, plagioclase 

gneiss, % mile west-southwest of locality of sample 4, table 1; 5, biotite quartz-monzonitic gneiss, Chapel Hill road, ~mile north of Four Corners, Montville quadrangle. 

2 Contains 0.04 percent rare-earth elements by semiquantitative spectrographic 

analysis (N. M. Conklin, analyst). 

oxygen may be replaced by OH, F, or possibly Cl. The 

variety keilhauite contains appreciable amounts of rare 

earths (Sahama, 1946, p.108). 

The anomalously magnetic sphene, san1ples 1 and 2 

(table 399.1) are richer in iron and minor elements than 

the other sphene from Connecticut, samples 3 and 4, and 

..,.. 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-4.3.5 D-311 

are relatively rich in rare earths. San1ple 1 is particularly rich in rare earths of the cerium group. The 

first two samples of sphene are keilhauite. Samples 

3 and 4 may be considered normal sphene. The relative rare-earth content of the sphene from Connecticut 

is directly proportional to the relative rare-earth content of the rocks from which they came (table 399.2). 

The plagioclase gneiss, sample 4 (table 399.2) is not the 

rock from which the sphene was taken, but is representative of the unit containing the sphene. Rare earths 

probably have little effect on optical properties of 

sphene. 

The low aluminum content of the sphene (sample 1) 

from the aegirine-augite granitic gneiss as compared 

with the aluminum content of other sphene from 

Connecticut possibly reflects the low aluminum content 

of the enclosing rock. The aegirine-augite granitic 

gneiss is ~1 subaluminous granitic rock in which th~ 

alumina content is insufficient to accommodate all the 

available alkali. Excess alkali is contained in the 

pyroxene. The rock has abw1dant quartz. 

Both the aegirine-augite granitic gneiss and the 

hornblende-bearing granitic gneiss are phacolithic or 

sill-like bodies in a complex of hornblende- and biotiteplagioclase gneisses and amphibolite, the complex from 

which the sphene (sample4) from the plagioclase-gneiss 

was taken. Rocks of this complex contain as much as 

2 percent sphene. Other granitic gneisses in southeastern Connecticut, related in composition and field 

relationships to the granitic rocks mentioned above but 

lying in quartzite and schist rather than mafic rocks, 

contain little or no sphene. Many of these granitic 

rocks contain appreciable cerium (sample 5-, table 

399.2). In these rocks, the rare earths are probably 

contained in allanite, monazite, and possibly biotite. 

Sphene is present only in fairly biotitic quartzmonzonitic gneiss. Sphene from such rocks has not 

yet been analyzed. Semiquantitative spectrographic 

analyses of specimens of Canterbury gneiss, the source 

of sphene sample 3, rarely show the cerium-group rare 

earths, in contrast to their common presence in analyses 

of the group of granitic gneisses to which the aegirineaugite granitic gneiss, the hornblende-bearing granitic 

gneiss, and the quartz-monzonitic gneiss belong. 

Young ( 1938) identified keilha uite in Rhode Island 

in rocks now called the Scituate granite gneiss (Moore, 

1958) and suggested (Young, p. 152) that keilhauite 

1night be a guide mineral to these rocks. The consanguinity of the Scituate granite gneiss with granitic 

gneisses in adjacent southeastern Connecticut containing keilhauite has not yet been proved, but the samples 

from a group of granitic gneisses in southeastern 

Connecticut and Rhode Island contain a greater amount 

of rare earths, particularly of the cerium group, than 

the Canterbury gneiss. 

REFERENCES 

Moore, G. E., 1958, BedrO<!k geology of the Hope Valley 

quadrangle, Rhode Island: U.S. Geol. Survey Geol. Quad 

Map GQ-105. 

Morgante, S., 1943, La titanite a terre rare del granito pegmatitico di Quoscescer : Periodico di Mineralogia (Rome), v. 14, 

p. 13-33. [Abstract in Minerolog. Abs., v. 9, p. 216, 1946.] 

Sahama, T. G., 1946, On the chemistry of the mineral titanite: 

Comm. geol. Finlande Bull., no. 138, p. 88-120. 

Young, J. A., Jr., 1938, Keilhauite, a guide mineral to the 

Sterling granite gneiss of Rhode Island : Am. Mineralogist, 

v. 23, p. 149-152. 

400. MINERALOGY OF MICACEOUS LAMINAE IN SANDSTONES OF PALEOZOIC AGE IN FLORIDA 

By DoROTHY CARROLL. Washington, D.C. 

Work done in cooperation witll, the U.S. Atomic Energy Commission 

Many sandstones of Paleozoic age in Florida consist 

of thin-bedded silty rocks containing fine, 1nicaceous 

laminae. Jean M.13erdan, U.S. Geological Survey, supplied a sample of the core from 3,668 to 3,671 feet in the 

I-Iazel Langston well 1, Dixie County, Fla., in which 

mica is unusually abundant. In this rock, laminae of 

mica about one-half millimeter thick are separated by 

about 5 millimeters of silty sandstone.' Mica from.two 

of these laminae was exmnined by means of X-ray diffraction and with the petrographic microscope. 

Samples of mica were obtained by scra.ping it off 

·the laminae with a razor blade. The mica is rather soft 

and inelastic, and although compacted into large aggregates by pressure of overlying rocks, it is easily disaggregated into individual flakes. The micaceous laminae contained no quartz, so no concentration of the 
D-312 GEOLOGICAL SURVEY RESEARCH 1 9 61 

samples was required. X-ray diffraction patterns were 

made using nickel filtered Cul{a radiation,>.. 1.54050A, 

of oriented and unoriented samples of mica treated 

in various ways. The X-ray diffraction data are given 

3.32A 

3.53A 

2.49A 

in table 400.1, and tracings of the diffraction patterns 

are given in figures 400.1-400.4. 

The ·x-ray spacings of an oriented sample of mica 

(fig. 400.1) suggest that the sample contains inter9.81 A 

4.97A 

7.01A 

38 34 30 26 22 18 14 10 6 2 

DEGREES 28 

FIGURE 400.1.-X-ray diffraction of an oriented sample of mica.· Scanning speed 2° 29 per minute, scale factor 8, 

multiplier 1, tinie constant 4 seconds. 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 

14 .12 10 

10.04A 

8 

DEGREES 28 

6 4 2 

GLYCOLATED 

H Cl, 1 +1 

BOILED 1 HR 

KCI, 1N 

BOILED 7 HRS 

UNTREATED 

li'rounE 400.2.-X-ray diffraction patterns of oriented samples of mica after the treatments indicated (nickel filtered OuKa radiation, scanning speed 1 o 28 per minute, seal~ factor 8, multiplier 1, 

time constant 4 seconds) . 

604493 0-61-21 

D-313 
D-314 GEOLOGICAL SURVEY RESEARCH 19 6 1 

10.15A 

9.88A 

10 9 8 7 

DEGREES 28 

FIGURE 400.3.-X-ray diffraction pattern of mica sample heated 

to 300°0 showing the resolution of the lOA spacing into two 

distinct peaks (nickel filtered CuKa radiation, scanning speed 

~ o 28 per minute, scale factor 8, multiplier. 1, time constant 4 

seconds). 

layered mica and hydrous mica (spacings of 10.70A and 

11.47A) with interlayered vermiculite (14.7A) and 

chlorite (7.4.A). Table 400.1 column 2, gives the spacings obtained from an unoriented sample prepared by 

spreading a thin layer of mica on the rippled surface of 

masking tape on an aluminum holder. There is an 

64 62 

1.500A 

60 

DEGREES 29 

58 

FIGURE 400.4.-X-ray diffraction pattern of the 060 reflection 

of mica obtained from a polished section of rock cut at right 

angles to the bedding (nickel filtered CuKa radiation, scanning speed 1 o 28 per minute, scale factor 8, multiplier 1, time 

constant 4 seconds). 

integral series of 001 spacings from 002 to 0.0.10 for 

mica. T.he 060 spacing at 1.48A indicates that the 

mica is dioctahedral. 

Samples were glycolated, treated in HCl, in lN l{Cl, 

and heated .at 300°C, 600°C, and 700°C. The X-ray 

data of samples after these treatments are given in table 

4QO.l, columns 4 to 9, and in figure 400.2. 

Boiling either in H:Cl ( 1 + 1) for one hour or in lN 

KCl for 7 hours shifted the 14A spacing to .--llA. 

Upon heating to 300°C two spacings oontering around 

lOA developed; one is at 10.21A, and the other at 9.92A 

(fig. 400.3). The 14A spacing was shifted to 11.3A. 

Heating a sample at 600°0 ren1oved the 7A spacing 

but left the ll.A spacing unchanged. At 700°C the llA 

spacing disappeared and only the integra.] series of 001 

spacings of mica remained. A polished section of the 

rock cut at right angles to the bedding gave a number 

of hkl mica reflections (table 400.1, column 3). The 

two 060 reflections at 1.49A and 1.50A respectively suggest that two polymorphs of muscovite are present (fig. 

400.4). 

All the spacings of mica identified in the X-ray patterns are assembled in table 400.1, column .. 10. Indices 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-4.3.5 D-315 

TABI~l<J 400.1.-X-?·ay diffraction data (Cu KaNi filtered radiation X= 1.51,.050A) for micaceous samples from silty sandstone, 3,668 

to 3,671 feet in the Hazel Langston wellt, Dixie County, Fla. 

Or!-

en ted, 

untreated 

(I) 

d(A) 

14. 71 111. 47 210. 70 

8 8. 18 

7. 43 

5. 15 

4. 87 

Unorien ted, 

untreated 

(2) 

d(A) 

14. 47 

Hock slice, perpendicular to bedding 

(3) 

d(A) 

14. 4 

Unoriented, 

Oriented, ' HOI, 1+1, 

glycolated boiled 1 hr. 

(4) (5) 

d(A) 

14. 24 

d(A) 

Oriented, 

1NKCI, 

boiled 

7 hrs. 

(6) 

d(A) 

1 11. 04 1 11. 11 

10. 15 - - - - - - - - 10. 04 10. 04 10. 15 

- - - - - - - - - - - - - - - - - - - - - - - - 3 8. 03 

7. 18 -------- 7. 13 7. 24-7. 24 

5. 03 - - - - - - - - 5. 00 4. 99 

4. 79 4. 71 - - - - - - - - - - - - - - - - - - -

7. 13 

5. 02 

4. 77 

Oriented, 

300° c 

half hom 

(7) 

d(A) 

1 11. 32 

2 10. 21 

9. 92 

Oriented, Oriented, Muscovite (from all X-ray patterns) 60()00 700° c 

half hom half hom 

All spacings Indices Type 

(8) (9) (10) (11) (12) 

--·-

d(A) d(A) d(A) ---------- ----------

1 11. 55 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2 10. 51 10. 04 10. 04 002 2M1 

7. 36-7.24 ----------- -------- ----------- ---------- ----------

5. 04 5. 12 5. 00 5. 00 004 2M., 1M 

------ ------------------------------------------- -··--------- 4. 54 -------- 4. 52-4.48 110 2M., 1M 

--- - -- -------- -------- -------- ----------- -------- ----------- . 4. 37 -------- ----------- ---------- ---------- _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _______ ·- _ _ _ - _ _ _ _ _ _ _ _ _ _ .. _ _ _ _ _ _ 4. 30-4. 28 111 2 M1 

------ ----------------------------------- ____ , ___ 4. 06-3.88 4. 07-3.96 ---------------------------------------

--------------------.----------------------------------------------------------- 3. 8H 113 2M1 

3. 7.5 3. 71 3. 71 -------- 3. 68 3. 68 3. 72 3. 78-3. 75 -------- 3. 72 023 2M1 

3. 61 -------- ---------------- ___________ · -------- 3. 63-3.60 ' ___________ -------- --------------------- ----·------

3. 56 -------- -------- 3. 57 3. 55 3. 51 3. 54 -------- ----------- ---------- ----------

3. 39 3. 34 -------- -------- 3. 32 3. 33 3. 35 3. 36 3. 34 3. 36 006 2M1, 1M 

3. 25 3. 20 3. 19 -------- ----------- 3. 21 ----------- 3. 25 -------- 3. 2-2 114 2M1 

----------------------------------------------------------------------- ________ 3.12 110 2M1 

3. 01 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - ____ - __ - _ - - _ _ _ _ _ _ - - - _ _ _ _ _ _ _ _ 3. 03 _ _ _ _ _ _ _ _ 3. 00 025 2 M1 

2. 99 2. 93 -------- ----------- 2. 99 3. 02-2. 97 2. 90 -------- ----------- ---------- ----------

2. 83 -------- -------- ----------- -------- 2. 84 2. 86 -------- 2. 87 115 2M1 

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2. 82 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

2. 61 2. 64 -------- ----------- ________ 2. 62 2. 64 -------- 2. 66 131 (?) 1M 

-------------- 2. 56 ------------------- ________ ---------------------- ________ 2. 58-2.56 ---------- 2M1, 1M 

2. 49 --------------------------- ________ 2. 49 ------------------- 2. 49 008 2M1 

-------------- 2. 24 --------------------------------------------------------- 2. 20 221,204 · 2M1 

------------------------------------------------------------------------------- 2.15-2.13 135,206 ----------

2. 04 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2. 04 - - - - - - - - - - - - - - - - - - - 2. 04 044 - - - - - - - - - -

2.00 2. 01 -------- ------------------- 2. 00 ------------------- 2. 00 0. 0.10 ----------

1. 92 - - - - - - - - - - - - - - - - - - - - - - --- - - - - - - - - - - 1. 92 - - - - - - - - - - - - - - - - - - - 1. 9Q-1. 89 208' - - - - - - - - - -

1. 65 -------- -------- ----------- -------- 1. 63 ----------- -------- ----------- ---------- ----------

1. 48 1. 49 - - - - - - - - - - - - - - - - - - - - - - - - - - - 1. 49 - - - - - - - - - - - - - - - - - - - 1. 50 060 - - - - - - - - - -

• Hydrated muscovite. 3 002 reflection of muscovite with partial collapse of hydrated layer. 

a Reflection duo to Interlayering of vermiculite and chlorite. 

are assigned to most of these spacings (table 400.1, 

column 11), a,nd the indices characteristic of the 2M1 

and 11\1 muscovite polymorphs are in column 12. The 

indices and polymorph identifications were obtained 

from Smith andY oder ( 1956). 

Chlorite spacings at ,_,7 A, 4.7 A, 3.5A, 2.28A, and 

2.24A were identified from 1\{artin (1955). These, togethm· with the ,_,14A spacing of chlorite plus vermiculite, are the unidentified spacings listed in table 1. 

A little vermiculite is probably interlayered with the 

chlorite. It is t1pparently dioctahedral as no reflection 

of a trioctahedral 060 spacing was obtained. The behavior of this vermiculite with various treatments is 

somewhat similar to that described by Brown (1953), 

Hathaway ( 1955), and Rich ( 1958). Spacings at 

,_, 11A and at 8-9A for the Florida mica are the same 

as those obtained by Rich ( 1958) for the earlier stages 

of weathered muscovite in a strongly leached soil developed from muscovite schist. The 7 A spacing in the 

Florida mica could be due to the presence of vermiculite, chlorite, or kaolinite. Various treatments (fig. 

400.1) suggest that this is the 002 reflection of chlorite. 

A differential thermal analysis by Robert 0. Fournier, 

U:S. Geological Survey, showed a broad low endothermic reaction at about 575°C, but no reaction for 

low temperature water or for kaolinite. Furthermore, 

no spacings, other than that at 7 A, characteristic of 

kaolinite were found. 
D-316 GEOLOGICAL SURVEY RESEARCH 19 6 ~ 

The mica has a ca.tion exchange capacity of 12.3 

milliequivalents (meq)/lOOg, a figure indicative of hydrated mica rather than of vermiculite. Rich ( 1958) 

reported that his soil vermiculite had a cation exchange. 

capacity of 50e-65 meq/100g. 

Microscopic examination shows that the sample consists of three minerals: colorless flakes of muscovite 

with indices of refraction al.55-1.56, yl.59-1.60, and 

2V ranging from 23° to 37° in different flakes; a 

brownish, degraded mica with index of refraction 

yl.62-1.63, and interference figure very weak or absent, 

and abnost uniaxial; and green flakes of chlorite with 

index of refraction y 1.61 +. A grain count shows that 

the sample contains 58 percent muscovite, 39 percent 

degraded mica, and 3 percent chlorite. 

In thin section at right angles to the bedding planes 

the micaceous laminae are seen to consist of folia of 

colorless mica about 0.06 mm across; brown pleochroic 

mica about 0.05 mm across; and green pleochroic 

chlorite about 0.02 mm across. The folia are elongated 

and appear to have developed schistosity through pressure. H'Owever, the presence of a 14A spacing in the 

diffraction pattern obtained from the polished rock 

(table 400.1, column 3) suggests that chlorite may have 

developed diageneticall y. 

The minerals present in the Florida samples are 

similar to those described from the Jacksonburg formation (Middl~ Ordovician) of Pennsylvania and New 

Jersey by Ray and Gault (1961). 

The mica in the Florida samples is considered to be 

detrital. The flakes were probably floated onto the surface of the fine sandy beds by gentle current action, 

either some distance from a shoreline or in a quiet bay 

that received little coarse detritus. The mica could also 

have been sorted out from the silty sand after deposition 

but prior to the addition of further layers of silt. 

REFERENCES 

Brown, George, 1953, The dioctahedral analogue of vermiculite : 

Clay Minerals Bull., v. 2, no. 10, p. 64-70. 

Hathaway, J. C., 1955, Studies of some vermiculite-type clay 

minerals, in Milligan, W. 0., ed., Clays and clay minerals: 

Natl. Research Council Pub. 395, p. 74-86. 

Martin, R. T., 1955, Reference chlorite characterization for 

chlorite identification in soil clays, in Milligan, W. 0., ed., 

Clays and clay minerals: Natl. Research Council Pub. 395, 

p.ll7-145. 

Ray, Satyabrata, and Gault, H. R., 1961, Mineralogy of the 

Jacksonburg (Middle Ordovician) formation in eastern 

Pennsylvania and western New Jersey: Am. Assoc. Petroleum Geologists Bull., v. 45, p. 39--50. 

Rich, C. 1., 1958, Muscovite weathering in a soil developed in 

,the Virginia Piedmont, in Swineford, A., ed., Clays and clay 

minerals: Natl. Research Council Pub. 566, p. 203-212. 

Smith, J. V., and Yoder, H. S., 1956, Experimental and theoretical studies of the mica polymorphs: Mineralog. Mag., v. 

31, p. 209--235. 

401. GEOCHEMICAL ANOMALIES IN THE UPPER PLATE OF THE ROBERTS THRUST NEAR CORTEZ, NEVADA 

By R. L. ERICKSON, HAROLD MASURSKY, A. P. MARRANZINO, and UTEANA OoA, Denver, Colo. 

Analyses of siliceous clastic rocks in the upper plate 

of the Ro~rts thrust fault near Cortez, Nev., show a 

wide range in metal content. The highest concentrations of metals occur along normal fa,ult zones that cut 

both upper and lo,ver plates of the thrust, and they 

may represent leakage halos (Hawkes, 1957, p. 241) 

up-rake from concealed ore deposits in the thrust zone 

and in the carbonate rocks below the thrust. Interest 

in a geochemical investigation of the area was aroused 

by the intense kaolinitic alteration and the copper mineralization in bedded chert at the Whitehorse Turquoise 

mine and at other prospect pits along the Whitehorse 

fault zone. The study was directed toward the development of geochemical techniques and methods that 

might a.id in the search for ore deposits concealed· by 

the Roberts thrust and similar thrust sheets in northcentral Nevada. 

The geology of the area studied was partially remapped on a topographic base at a scale of 1: 24,000 

and recompiled from recent geologic mapping of the 

Cortez 15-minute quadrangle by James Gilluly and 

Harold Masursky. 

The area is on the west side of the Cortez windo\v 

(Roberts and others, 1958) in which an autochthon of 

Paleozoic carbonate rocks is overridden by an allochthon of Paleozoic siliceous clastic rocks along the Roberts thrust. The lower plate in the mapped area is 

made up of gray to black thin-bedded a.rgillaceous 

Roberts Mountains formation of Silurian age, and alternating thick beds of light- to dark-gray bioclastic limestone and thin-bedded argillaceous limestone of Devonian age. The upper plate contains gray shale and 

black chert of the Vinini formation of Ordovician age; 

shale, chert, and dolomitic siltstone of Silurian age; and 
•. 

SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-43.5 .D-317 

chert with limestone interbeds of probable Devonian 

age. Several key beds of limestone and chert in the 

dominantly chert section are shown on the geologic map 

(fig. 401.1). 

In fault contact with the Paleozoic sedimentary rocks 

is a thi0k sequence of rhyolitic welded tuffs of Tertiary 

age ( l\1asursky, 1960) that contains many vitrophyre 

beds and gravel interbeds (fig. 401.1). Tertiary dikes 

and sills of quartz porphyry, latite, and hornblende 

porphyry are lumped together on the geologic map (fig. 

401.1). l\1uch of the area is blanketed by alluvium and 

pediment gravels of Quaterna.ry age. 

The rocks were analyzed in the field for trace 1netal 

content by use of the mobile spectrographic laboratory 

of the U.S. Geological Survey. About 500 rock samples were analyzed for 27 elements, representing nearly 

14,000 individual determinations. Spectrographic results were received and plotted daily, thus helping to 

guide the geologic mapping and sampling program. 

For the purpose of this report, the results are presented 

in generalized forn1 showing only the areas o:f highest 

concentration of Cu, Pb, Zn, Bi, Mo, Ag, and As. 

Figure 401.2 shows that the areas of highest metal 

concentrations in the upper plate are alined along 

faults and are conspicuously zoned. The known 

"highs" of greatest areal extent are nmnbered on the 

geochemical map, and the maxim.um metal values obtained within individual "highs" are shown in table 

401.1. 

The highest copper concentrations occur in bleached, 

a.rgillized, a.nd pyritized chert breccia along the eastwest high-angle vVhitehorse fault zone, which is offset 

by a branch of the post-mineralization frontal fault. 

Turquoise is 1nined within localities 13 and 10; cuprite 

occurs in the central pitrt of locality 10; malachite and 

azurite stain chert breccia in locality 12. 

l.,he highest lead, molybdenum, and silver concentrations occur at locality 15, where a narrow galena-bearing qunrt.z vein with as much as 1500 ppm (parts per 

TABLE 401.1.-Maximum m(,tal values determined by semiquantitative spectrographic method within numbered localities 

Motols 

[Localities shown on fig. 401.2] 

>10,000 5,000 2,000 

Co neon tration (parts per million) 

1,000 700 200 100 50 20 10 

-------1----1---------------

Cu_________ 10, ll 12, 13 ----------- ----------- 4, 7 -------- ___ . ______________ _ 

Pb......... 15 ------ . 20 17 18 3, 13,21 ------ ---- ---- ----

Zn ••••••••• -------- 11 5,15,16,20 6,12,13,21 •.•. -------------- ___________ _ As _________ -------- 17 6, 15, 1, 21 14 ____ -------- _________________ _ 

l\fo •.•••••• -------- ------ ----------- -----· _____ ____ 15,18 10,11 ___________ _ 

DL •••••••• -------- ------ ----------- ----------- ---- 2, 4 ------ 8, 9 ---- ----

Ag ••••••••• -------- ------ ----------- ----------- ---- -------- ------ 15 7 18 

million) silver is exposed in the roof of a short adit. A 

double salt of phosphate-sulfate was separated from soft 

earthy yellow-brown material in a shear zone in this 

adit. · The mineral, tentatively identified by X-ray 

methods as a member of the beudantite group by F. A. 

Hildebrand (oral communication 1961), contains more 

than 1 percent each of Ph, 1\fo, and Ag. Two thousand 

ppm Ph and 20 ppm Ag were :found in gossan in locality 

20; 1,500 and 1,000 ppm Ph in brecciated chert at the 

north ends of localities 12 and 17, respectively; and 500 

to 700 ppm Pb, 10 ppm Ag, and 200 ppm Mo in fracturefilling material at locality 18. l\folybdenum also occurs 

in mnounts up to 150 ppm ·within the copper zone. 

Zinc, in concentrations greater than 1000 ppm, occurs locally in all zones but is consistently present in the 

Pb-Zn-Ag zone (fig. 401.2). 

The highest concentrations of arsenic (up to 5,000 

ppm) occur in altered chert breccia near the Roberts 

thrust and the Copper fault, which bound the block of 

siliceous clastic rocks. In the eastern part of the 

mapped area, the arsenic zone overlaps the Pb-Zn-Ag 

zone as far north as locality 5 (fig. 401.2). 

The highest concentrations of bismuth occur in gossan in the eastern part of the mapped area at locality 2 

(300 ppm), and in pyritized and silicified chert breccia 

at locality 4 (200 ppm). Soft yellow earthy material in 

gossan at locality 2 contained 1,500 ppm Bi. The extent 

of the Bi zone is 11ot known because of the gravel and 

alluvium cover to the east and the Tertiary volcanic 

cover to the south. 

The highest concentration of manganese is at the 

western end of the mapped area. Lovering ( 1949) 

showed at Tintic, Utah, that manganese was commonly 

concentrated on the up-rake or outlet side of mineralized conduits. This suggests that the 1netal-bearing 

solutions moved from east to west with both horizontaJ 

and vertical components along the east-west fault zones. 

The manganese "high:' area would be the cool or outlet 

side and the bismuth "high" would be a higher temperature zone closer to the source of the metal-bearing 

solutions. 

This area appears favorable for the discovery of concealed ore deposits because: 

1. The rock alteration and the concentration and zoning 

of metals along high-angle normal faults that cut 

both upper and lower plate rocks may be leakage 

halos fron1 ore deposits in the thrust zone or in the 

carbonate rocks below the thrust. The intersection of 

the mineralized faults with the thrust plane should 

be favorable ground. The thickness of the upper 

plate rocks is not known and detailed rock-alteration 

studies, which might help determine the validity of 

the leakage halo concept, are yet to be made. 
D-318 GEOLOGICAL SURVEY RESEARCH 1 9 6 1 

EXPLANATION 

Alluvium 

To, vit·rophyre beds. 

Tg, gravel beds 

Gravel H <{ 

Intrusive ~ rocks ): ~ 

Quartz porphyry ~ 

and latite 

ROBERTS THRUST 

UPPER PLATE LOWER PLATE 

--Contact 

Dashed where inferred 

-r-Y"" ---. .., •. 

~20 

Dip of fault and plunge 

of lineation 

4~ 

Thrust fault Strike and dip of beds 

Dashed where inferred; 

dotted where concealed; 

teeth on ·uppe·r plate Mine adit \.) ......... ~ Fault 

0 R. 47 E. 

• 

NEVADA 

1 MILE Geology modified from James Gilluly 

and Harold Masursky, 1957-59 

FIGURE 401.1.-Preliminary geologic map of the north end of the Toiyabe Range, Cortez quadrangle, Nevada. 
T. 

26 

N. 

SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-435 

EXPLANATION 

Copper zone 

Lead-zinc-silver 

- zone 

Arsenic zone 

Bismuth • zone 

Area of high manganese 

concentration 

0 

/..... 

/.1D 

GY 

Areas of high metal concentration 

X 

Sample locality 

For explanation of geologic rock 

units see other illustration in this 

article. Only Quaternary units are 

shown 

Qg 

D-319 

\ 

\ 

\ 

\ 

\ 

v\o 

\ 

1\ \ I \ 

I -.._"" \ 

I f \ I I 

\ 1- \ \ I 

\\ \ '\ 

\ 

\ 

\ 

o\0 

\ 

\ 

' I 

I 

J 

I 

I 

~----._---------.--11~6~.4~0-.--------------~----R-.-4-7-E-.----------------------~---------------------------------~ 

0 1 MILE 

FIGURE 401.2.-Preliminary geochemical map showing distribution of copper, lead-zinc-silver, arsenic, and bismuth in the upper 

plate rocks of the Roberts thrust, Cortez quadrangle, Nevada. 
D-3,20 GEOLOGICAL SURVEY RESEARCH 19 61 

2. The mineralized fauJt zones and quartz porphyry 

dikes in the area of investigation can be projected on 

strike 2 miles southeastward across a gravel-covered 

pediment into the Cortez district where ore deposits 

in Paleozoic carbonate rocks of .the lower plate have 

produced silver, lead, zinc, copper, and gold with a net 

value of more than $12,000,000 (Emmons, 1910; Vanderburg, 1938). The pediment is favorable ground 

also and the depth to bedrock probably is very 

shallow. 

Geochemical investigation of upper plate rocks near 

other windows that have been productive in north-central Nevada may reveal target areas similar to that 

described in this report. 

REFERENCES 

Emmons, W. H., 1910, A reconnaissance of some mining camps 

in Elko, Lander, and Eureka Counties, Nevada: U.S. Geol. 

Survey Bull. 408, p. 99-106. 

Hawkes, H. E., 1957, Principles of geochemical prospecting: 

U.S. Geol. Survey Bull. 1000-F, p. 225-355. 

Lovering, T. S., 1949, Rock alteration as a guide to ore-East 

Tintic District, Utah: Econ. Geology Mon. 1, p. 57. 

Masursky, Harold, 1960, Welded tuffs in the northern Toiyabe 

Range, Nevada, in Short papers in the geological sciences: 

U.S. Geol. Survey Prof. Paper 400-B, p. 281-283. 

Roberts, R. J., Hotz, P. E., Gilluly, James, and Ferguson, H. G., 

1958, Paleozoic rocks in north-central 'Nevada : Am. Assoc. 

Petroleum Geologists Bull., v. 42, no. 12, p. 2813-2857. 

Vanderburg, W. 0., 1938, Reconnaissance of mining districts 

in Eureka County, Nevada: U.S. Bur. Mines Inf. Circ. 7022, 

p. 28-28. 

402. RADIATION DAMAGE AND ISOTOPIC DISEQUILIBRIA IN SOME URANIUM-BEARING ASPHALTITE 

NODULES IN BACK-REEF DOLOMITES, CARLSBAD, NEW MEXICO 

By ARTHUR P. PIERCE and JoHN N. RosHOLT, JR., Denver, Colo., and Miami, Fla. 

Uranium-bearing asphaltite nodules in marine carbonate-evaporite rocks of Late Permian age have been 

studied in detail in the Rocky Arroyo area near Carlsbad, N. Mex. The nodules occur in silty sandstone, 

sh~tllow-marine algal dolomite, and dolomitic limestone 

that are part of the back-reef facies of the· Capitan reef. 

Most of the known occurrences are in the Yates and 

Seven River formations. 

In the Rocky Arroyo area the distribution of the 

uraniferous asphaltite correlates well with that of 

asphaltic sandstone which transgress the facies changes 

and which probably served as channel ways for mineralizing solutions. According to 'Valtman ( 1954) these 

substances may be responsible for abnormally high 

radioactivity recorded by gamma-ray logs in hundreds 

of wells penetrating these formations along the flanks 

of the Delaware basin north of the Rocky Arroyo area. 

A most striking geologic feature in the sedimentary 

formations of the R9cky Arroyo area is the abrupt 

lateral change in lithology between gypsum, red shale, 

and sandstone to the west, and bituminous marine dolomite to the east. The carbonate-sulfate facies changes, 

which are only a few miles wide, occur progressively farther eastward in the younger formations. 

These facies changes have been an important geochemical control on mineralization of the rocks. 

Asphaltite nodules occurring in dolomite close (within 

tens of feet) to carbonate-sulfate contacts are encased 

by shells of pyrite and marcasite, whereas asphaltite 

nodules occurring at greater distances from the 

carbonate-sulfate contacts are associated with only 

traces of sulfide minerals. 

The distribution of the asphaltite in the dol01nites in 

the Rocky Arroyo area is locally controlled by fractures, 

bedding planes, stylolites, and fossil1nolds. Studies of 

sawed rock sections show that many of the nodules have 

been deposited within preexisting gastropod and 

mollusk molds. Most of the nodules both fill the molds 

and replace the surrounding dolomite. A part of the 

missing carbonate may be represented by vugs or molds 

in which calcite crystals are surrounded by asphaltite 

whose uranium content increases from several parts per 

million in the center to a few percent at the sharp 

boundaries where the asphaltite replaces the surrounding dolomite. There is a parallel increase in the sulfur 

content of the sa.me samples (table 402.1). The 

mineralized rocks contain patches of residual oil, and 

the dolomite beds away from the mineralized fracture 

zones contain numerous fossil molds filled with petroleum that carries only 1 part per million or less of 

uranium. As noted above, mineralizing sulfate solutions probably migrated laterally through sandstone 

from the evaporite facies, and ascended through fractures into the petroliferous back-reef dolomite. 
-4. 

SHORT PAPE·RS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-43.5 D-321 

TABLE 402.1.-Chemical properties of some uranium-bearing asphaUites 

Estimated 

Sample Organic analysis in weight percent 2 gena ted percent dehydro- carbon in percent Equiva- Carbon: of carbonlent hydro- uranium gen Fusibility (alpha weight From From count ratio carbon: From carbon: 

No. Description 1 Ash c H N 0 s percent) (per- hydrogen theory hydrogen cent) ratiosrel- (see ratios relative to text) ative to sample 7 sample 8 

-- -------- ------------

1 Outermost asphaltlte from vugs In dolomite Seven 5.06 64.44 4.10 0.30 5. 90 25.57 Infusible ____ 2.2 15.7 48 50 52 

Hlvers formation. 

2 Aspllaltlte between samples No.1 and No.3 _______ 4. 87 64.97 4.49 .38 4. 98 23.75 _ ____ do _______ 1.4 14.5 44 43 48 

3 Asphnltlte between samples No. 2 and No. 4 _______ 5.87 69.88 5. 65 .30 ------ 16.61 _ ____ do. ______ .6 12.4 35 31 40 

4 Asphnltlte between samples No.3 and No.5.----- 6.32 70.50 6.34 .88 2.45 13.51 _____ do _______ .3 11.1 27 23 32 

5 Asplmltlto between samples No.4 and No.6------ 3. 04 73.32 8. 26 .38 5. 76 3.04 _____ do _______ .03 8. 9 9 8 16 

0 Asplmltlto next to calcite at center of vug __________ 1. 59 81.45 9.42 1. 33 2. 41 3. 79 Fusible _____ .007 8. 6 6 4 13 

7 Aspllnltlto associated with calcite at center of vug __ ------ 82.50 10. 13 ------ 3. 57 5. 72 _____ do _______ <.003 8.1 0 <2 7 

8 011 cxtrnct from same dolomite bod about 20 feet ................. 79.31 10.56 .49 8. 46 2.37 Liquid ______ ---------- 7. 5 ---------- ---------- 0 

from above samples. 

1 Sample Nos. 1, 2, 4, and 5 wore previously described in Pierce, Mytton, and Barnett (1958). 

2 Organic analyses by H. S. Clark, Clark Microanalytical Laboratory, Urbana, Ill. The samples were vacuum dried at room temperature before analysis. Weight losses 

wore a few tenths porcont or less. · 

Deposition of the asphaltite nodules was a comparative{y late event in the diagenesis of these rocks. The 

nodules post-date lithification, stylolitization, and at 

least one episode of rock fracturing. They may be 

contemporaneous with or postdate an episode of petroleum migration. The apparent ages of the nodules, as 

calculn.ted from lead isotope, lead, and uranium analyses (table 402.2), are discordant and range from 203 

to 270 million ye~trs. It was assumed in calculation 

that the inherited common lead (about 3 percent of the 

totnJ lead) had the same composition as lead in galena 

fl'om a nea.rby sandstone lead deposit in the Abo formation of Early Permian age (provided by R. S. Cannon, 

Jr.). As most of the lead in the nodules is radiogenic, 

the cnJculated ages do not depend greatly upon this 

assumption. For example, a trial correction for inherited "anomaJous" lead like that from lead· deposits 

in Paleozoic limestones in the Mississippi Valley region 

gave apparent ages within several percent of those 

given below. The principal discrepancy in the age 

calculations of the asphaltite nodules is the difference 

between the ages calculated directly fron1 uranium and 

actinium series decay, and that calculated from the 

ratio of their products (Pb207 /Pb206 ). The latter ratio 

gives a value of about 270+65 1nillion years, most of 

the error being due to uncertainties in physical constants (Stief! and others, 1959). The calculated Pb207 I 

Pb206 age does not depend on the chemical uranium and 

lead analyses, and when compared to the other data 

suggests that losses and additions of parent and daughter radioelements may have oceurred during the history 

of the sample. Evidence regarding these possibilities 

is discussed below. 

Studies of the effects of radiation dmnage in and 

about the nodules show several phenmnena that can be 

correlated with their age and their overall isotopic 

equilibria. Data on radiation damage in the organic 

substance suggest that the nodules may have been fluid 

during a relatively long period in their early history. 

Data on thermoluminescence and radioisotopes in the 

TABIJE 402.2.-Lead isotope, lead, and urani1tm analyses of asphaltite nodules from the Rocky Arroyo area near Carlsbad, N. Mex. 

Sample Atomic ratios 1 Weight perrent 2 Calculated ages, in millions of 

No. Description Pb206/Pb20B Pb207/Pb20S Pb204/Pb20B Pb u Th Pb206/ 

- {T238 

1 Composite of several asphaltite 

nodules _____ - - - _ 30. 338 ±.002 1. 943 ±. 002 0. 0342 ±.0004 0. 062;.061 2. 20; 2. 15 <o. ooo1 203±20 

2 Assumed isotopic 

composition of 

inherited lead s ___ 0. 4864 ±.0004 0. 4057 ±.0005 0. 0261 ± .0003 -a•-------- ---------- -------- -------

I Load IRotopo analyses by W. D. Harman, Union Carbide Nuclear Corp., Oak Hidge, ·Tenn., rurnished by L. R. Stieff and T. W. Stern. 

2 Analyses by Frank Cuttltta. 

a Common load correction was made with reference to Pb20s. 

years a 

Pb207/ Pb207/ 

U233 Pb206 

208±20 270±65 

------- -------
D-322 GEOLOGICAL SURVEY RESEARCH 19 61 

dolomite surrounding the nodules indicate thaL the 

asphaltite has lost uranium and daughter products 

during at least its recent history. 

Radiation damage within the organic matrix of the 

nodules has caused systematic changes in their physical 

and chemical properties. The principal effects that 

correlate with increasing radiation dosage, or age and 

uranium content, are a progressive loss of hydrogen and 

destruction of original aliphatic structures (Pierce, 

Mytton, and Barnett, 1958). Similar effects are observed during irradiation of organic substances in 

nuclear piles and other radiation sources, and must 

occur in nature as well. Laboratory studies (Charles by, 

1954) show that the main effect of irradiation of 

paraffinic hydrocarbons is _ to break aliphatic carbonhydrogen bonds, whereupon hydrogen is released and 

the free carbon cross-links with carbon in other malecules. As the process continues all the molecules 

eventually become linked together to form an infusible, 

insoluble, immense polymer molecule. Charlesby 

(1954) has shown that infusibility corresponds to one 

cross-link per molecule of hydrocarbon, and occurs 

quite abruptly at a radiation dosage proportional to 

1/n, where n is the number of carbon atoms in the 

original molecule. 

In a previous investigation, oil from these rocks was 

found to be rich in dioctylphthalate and iso-octane 

(Pierce, Mytton, and Barnett, 1958). Complete polymerization of the phthalate ester corresponds to crosslinking of 1 of 24 or about 4 percent of the carbon 

atoms, whereas complete polymerization of the isooctane corresponds to cross-linking of about 13 percent 

of its carbon atoms. The amount of cross-linking required for infusibility (or complete polymerization) of 

a mixture of the two compounds should be between 

these t .. ro values. Assuming that this is the case, the 

fmdion of dehydrogenated or "cross-linked" carbon in 

the asphaltite samples has been estimated (table 402.1) 

by assuming that the initial C/H ratio of the asphaltites ''as either the same as that of the least radioactive sample or the oil. These estimates indicate that 

infusibility corresponds to cross-linking of about 6 to 

13 percent of the carbon atoms (such as sample 6, table 

402.1), which is within the range expected from the 

composition of the oil. 

Laboratory measurements show that. at low radiation 

intensities, reaction rates for cross-linking usnally vary 

as the square root of the radiation intensity ( Charlesby 

and Swallow, 1959). Similar reactions may go on in the 

solid asphaltites because of the intense local ionization 

produced by alpha particles. Trial calculations (table 

402.1) indicate that a second-order reaction of this kind 

fits the data fairly closely; however, other explanations 

based on the inhibiting effect of sulfur, and on recombination of hydrogen with reactive carbon, may do as 

well. X-ray measurements indicate that the end product of cross-linking and associated reactions is "graphitic" carbon, the proportion of which increases with 

dehydrogenation (Pierce, Mytton, and Barnett, 1958). 

If we assume that the rate at which the hydrogen 

atoms are lost from the asphaltite is proportional to the 

number remaining, we find that the samples in table 

402.1 were fusible, and very probably liquid at rock 

temperatures during the first 10 to 20 percent of their 

existence. During this time the asphaltites were probably part of a continuous phase with interstitial fluids 

in the rock. The distribution of uranium in the asphaltite-filled vugs shows that it could have been deposited 

gradually from surrounding solutions. Addition of the 

uranium during a relatively long period of time might 

account for the discordant isotopic age results discussed 

above. 

Radiation damage around the nodules is recorded as 

halos of intensely thermoluminescent dolomite (fig. 

402.1). The halos have an average width of about' 1.5 

FIGURE 402.1.-Thermoluminescence photograph of a uranium-· 

bearing asphaltite nodule in dolomite. 

mm. The luminescence intensity decreases outward and 

the widths of the halos tend to be independent of the 

sizes of the related nodules. The dimensions of these 

halos are greater than can be accounted for by alpha 

particle ranges (about 40 microns iL CaC03 ), but are 

about the same as the beta particle ranges, which 

penetrate up to about 4 mm in rock (Yagoda, 1949). 

Although beta radiation appears to provide a satisfactory explanation of the halos, a further investigation 

indicates the halos are enriched in radioisotopes. The 

radiochemical data (table 402.3) show that with the 

exception of ionium (Th230 ), uranium and actinium 

series daughters are impoverished in the nodule but 

enriched in the halo. The disequilibria shown by these 

data can be interpreted as (a) the product of geologi-
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-43:5 D-323 

TAJILE 402.3.-Radioisotope analyses of asphaltite nodules and 

associated dolomite 

Wcif(ht 

Smnplo percent • Percent equivalent uranium 

No. Description u Pam 'l'h230 H.a226 H.n22D 

- -------- 1 Composite or four asphaltitl' nodules •••••• 2 l. 4 l.(i§ 2.h l.9a 1. 67 

2 'l'hcrmoluminesccnt 

dolomite ft•om hnlos 

Slii'I'Otlllding sample 

L .. ------------------ .012. . 0074 . 004o .007t . 006 

a Dolomite surrounding 

samplo 2------------- .(1039 . 0042 .003o .0033 .004 

1 Fluoromctrlc umnln.m nnnlyscs by J. C. Antwcilcr and C. A. Horr. 

2 Insufficient samplo for repeat analysis. 

Pb2to 

--

1. 74 

.006a 

.0037 

cally recent events (several thousand years ago) in 

which uranium has migrated into the surrounding rock, 

and (b) as the result of steady migration of daughter 

products into the surrounding rock. For example, a 

i:ecent uranium loss of 40 percent and a continual 6 percent radimn n1igration would give three con~ordant 

ages of about 130 million years for the sample data in 

table 402.2. A decisive test as to the relative importance 

of such processes would be to analyze the lead isotopes 

in the thermoluminescent halos. 

REFERENCES 

Oharlesby, A., 1954, The cross-linking and degradation of paraffin chains by high-energy radiation : Royal Soc. London 

Proc., ser. A; v. 222, p. 60-74. 

Charlesby, A., and Swallow, A. J., 1959, Radiation chemistry, 

in. Annual Review Phys. Chemistry, v. 10: p. 289-330 . 

Pierce, A. P., Mytton, J. W., and Barnett, P.R., 1958, Geochemistry of uranium in organic substances in petroliferous rocks : 

United Nations Second Internat. Conf. Proc. on Peaceful 

Uses of Atomic Energy, Geneva, Sept. 1958, v. 2, P /780: p. 

192-198. 

Stieff, L. R., Stern, T. ,V., Oshiro, Seiki, and Senftle, F. E., 1959, 

Tables for the calculation of lead isotope ages: U.S. Geol. 

Survey Prof. Paper 334-A, p. 1-40. 

Waltman, R. l\L, 1954, Uranium in southeast New Mexico, in 

New Mexico Geol. Soc. Guidebook, 5th Field Conf.: p. 

113-114. 

Yagoda, Herman, 1949, Radioactive measurements with nuclear 

·emulsions: New York, John Wiley and Sons, Inc., 265 p. 

403. REGULAR INTERLAYERED CHLORITE-VERMICULITE IN EVAPORITE OF THE SALADO FORMATION, 

NEW MEXICO 

By RoBERT 0. FouRNIER, Washington, D.C. 

Parts of drill core from eight clay-rich horizons in 

evaporite of the Permian Salado formation were made 

avu,ilable for study through the kindness of Mr. Donald Rawson of the Lawrence Radiation Laboratory, 

University of California. The samples were from 

Gnome core, A.E.C. drill core 1, Eddy County, N.Mex. 

The depths at which the samples were taken are as 

follows: 

Srt1n1Jlo Depth in hole (feet) 

A------------------------------------ 986.6- 989.8 

B------------------------------------ 1026.5-1030.4 

0------------------------------------ 1070.1-1072.0 ])____________________________________ 1132.7-1135.0 

E------------------------------------ 1261.3-1261.5 

F------------------------------------ 1264.7-1264.8 

G------------------------------------ 1285.9-1286.0 

IL----------------------------------· 13'33.6-1333.7 

Red, brown, and gray clays are found as thin coatings on halite crystals and as dispersed flakes among 

sand grains in a matrix of evaporite minerals. All the 

samples studied contained large quantities of halite and 

smaller amounts of polyhalite, magnesite, anhydrite, 

and quartz. Elsewhere in the salt beds, sylvite, cal~lallite, and dolomite are present. 

The predominant clay mineral in seven of the samples is an alternating one-to-one regular interlayed 

chlorite-vermiculite. The eighth sample (sample H) 

contains mostly n1uscovite, a small ainount of the interlayered chlorite-vermiculite, and a larger quantity of 

muscovite randomly interlayed with either vermiculite 

or montmorillonite. Generally both muscovite and 

chlorite occur, at least in part, as pure members Inechanically mixed with the other clay minerals. The Inuscovite and chlorite are n1ost abundant in the coarser 

fractions and are probably detrital in origin. 

Diffractometer patterns of the interlayered chloritevermiculite are shown on figure 403.1 and the d spacings 

of the maxima are listed in table 403.1. Superimposed 

reflections from muscovite and chlorite limit the accuracy of the measurements. Grim, Droste, and Bradley 

(1960) report almost identical results fron1 clay in 

evaporite beds of the Salado formation, collected in 

mine workings of the U.S. Potash Co. at least 6 Iniles 

distant from the drill hole. 
D-324 GEOLOGICAL SURVEY RESEARCH 1 9 61 

Glycolated 

In 

Natural 

state 

In 

Heated 

3o5•c 

In 

In 

+ 

c 

25 

In 

n 

20 15 

29 (degrees) Cu (Ka.) 

In 

10 

In 

+ 

C In 

In 

5 

FIGURE 403.1.-X-ray diffractometer patterns for clay from 

sample D. In, interlayered chlorite-vermiculite; M, muscovite; C, chlorite. 

Grim and others (1960) give X-ray data ori.ly for 

the material in the natural state and after glycolation. 

These data alone are more consistent with those for 

. regularly interlayered chlorite and swelling chlorite or 

corrensite than with data for regular interlayered 

chlorite and vermiculite. Vivaldi and MacEwan 

( 1960) point out that the original corrensite as described by Lippman (1954) will expand from 28 A to 

approximately 31 A upon glycolation, but it will not 

contract below 28 A upon heating to 500°C. On the 

other hand, they point out that regular interlayered 

chlorite-vermiculite will collapse from 28 A to about 

24 A after heating to 300°C. However, Vivaldi and 

MacEwan expected ·that a regular mixed-layer chloritevermiculite would not expand from 28 A to 31 A upon 

treatment with ethylene glycol. The material reported 

on here does expand to 31 A upon treatment with 

ethylene glycol and it also contracts to about 24 A after 

heating to 120°C. It is assumed that the vermiculite 

unit is the expanding member, going from about 14 A 

to 17 A whereas the chlorite unit remains at about 14 A. 

Bradley ( 1945) had previously reported a vermiculite 

capable of being expanded with ethylene glycol from 

about 14 A to 17 A. 

The basal spacing of the interlayered vermiculitechlorite,is not sensitive to changes in relative humidity, 

and once it has been partially dehydrated by heating 

between 100°C and 500°C it does not quickly rehydrate 

under normal conditions in the air. It will, however, 

fully rehydrate when: it is placed in a water-saturated 

atmosphere for several minutes. Water is not readily 

lost from the interlayered position upon heating; 24 

hours at 120°C were required to collapse the structure to 24.5 A. 

To make certain that no rehydration was occurring 

in the interval between heating the sample and X-raying it, an oriented aggregate was X-rayed in an evacuated heating chamber mounted on a diffractometer. 

The results at a series of temperatures are shown on 

figure 403.2, and tabulated in table 403.2. There are no 

significant differences between the X-ray patterns obtained at temperatures from 120° C to 450° C. Between 

450° C and 510° C the chlorite portion of the structure 

collapsed from 14 A to 13.8 A and the 7 A and 8 A 

peaks disappeared. The 7 A peak was due to mecllanically admixed chlorite and the 8 A peak to the interlayered chlorite-vermiculite. The peak occurring at 

about 21.5 A for material heated between 120° C and 

510° C is anomolously low in d-spacing for a first-order 

basal reflection. The higher order reflections yield 

values of 24 A to 25 A for the basal unit. Between 

510° C and 620° C the 21.5 A peak collapses to about 

20.3 A. Similar 20 A and 21 A reflections have been 

reported for regular interlayered chlorite-montmorillonite (Earley and Milne, 1956; Earley and others, 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-43,5 D-325 

Natural state 

Mineral hkl 

In ___________ 001 

In, C ________ 002 

M ___________ -----·---

In ___________ 003 

In, c ________ 004 

In ___________ 005 

M ___________ --------

In, C ________ 006 

In, c ________ 008 

M ___________ --------

? ____________ --------

Jn___________ 00. 10 

M ___________ ---~----

In. _ _ _ _ _ _ _ _ _ _ 00. 14 

Room temperature 

Mineral hkl d (A) 

TABLE 403.1.-X-ray data for clay from sampleD 

[In, interlayered chlorite-vermiculite; M, muscovite; C, chlorite] 

Glycolated 

d(A) dxl(A) Mineral hkl d(A) dxl(A) 

30. 5 30. 5 In__________ 001 31. 5 31. 5 

In_ _ _ _ _ _ _ _ _ _ 002 15. 5 31. 0 

14. 26 28. 52 

10. 05 -------- In, M _______ 003 10. 05 30. 15 

9. 31 27. 93 ---- --------- -------- -------- --------

In __________ 004 

7. 17 28. 68 c ___________ --------

5. 61 28. 05 

In __________ 006 

4. 98 - - - - - - - - M __________ --------

4. 77 28. 62 C ___________ --------

In_ _ _ _ _ _ _ _ _ _ 007 

7. 83 31. 32 

7. 20 - - - - - - - -

5. 17 

4. 98 

4. 75 

4. 48 

31. 02 

31. 35 

Heated to 300° C 

Mineral hkl 

In_________ 001? 

c __________ -------- In_ _ _ _ _ _ _ _ _ 002 

M _________ --------

In_ _ _ _ _ _ _ _ _ 003 

c ______ . ____ -------- In _________ 004 

M _________ --------

In_________ 005 

In_ _ _ _ _ _ _ _ _ 006 

d(A) 

21. 3 

13. 9 

12. 54 

10.05 

8. 04 

dxl(A) 

21. 3? 

25. 08 

24. 12 

7. 14 ______ ..;_ 

5. 98 23. 92 

4. 98 - -· - - - - - -

4. 80 24. 00 

3. 95 23. 70 

In __________ 008 3. 85 30. 80 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

3. 56 28. 48 

3. 34 - - - - - - - -

3. 25 - - - - - - - -

2. 88 28. 8 

2. 50 - - - - - - - -

2. 05 28. 7 

c ___________ -------- In __________ 009 

M __________ --------

? ___________ --------

In_ _ _ _ _ _ _ _ _ _ 00. 10 

In__________ 00. 11 

M_ ---··--- -- -------- In__________ 00. 15 

3.56 -----·--- c__________ ________ 3. 53 _______ _ 

3. 4 7 31. 23 ------------ -------- -------- --------

3. 34 - - - - - - - -

3. 25 - - - - - - - -

3. 08 30. 8 

2. 83 31. 13 

2. 50 - - - - - - - -

2. 07 31. 05 

In_________ 007 

M _________ --------

? __________ --------

In _________ 008 

l\1_-------- --------

3. 43 24. 01 

3. 34 - - - - - - - -

3. 25 - - - - - - - -

2. 98 23. 84 

2. 50 - - - - - - - -

TABLE 403.2.-X-ray data for sampleD mounted in an evacuated chamber 

[In, interlayered chlorite-vermiculite; M, muscovite; C, chloritel 

510° c 620° c 

Mineral hkl d (A) Mineral hkl d (A) Mineral hkl d (A) Mineral hkl d (A) 

In_______ 001 30.5 In______ 001? 21.55 In______ 001? 21. 55 In______ 001? 20.3 In______ 001? 20. 10 

In, c_____ 002 14. 14 c _____________ 14. o3 c _____________ 13.81 c _____________ 13. 60 c _____________ 13.40 

--------- ------ ------- In______ 002 12.63 In______ 002 12. 11 In______ 002 11.79 In______ 002 11. 63 

M _______ ------ 10.00 M ______ ------ 10.00 M ____________ 10.00 M ______ ------ 10.00 M __ .. ____ ------ 9. 94 

In_______ 003 9. 21 --------- ______ ------- --------- ____________________________ ------- --------- ------ ------

---------------------- In______ 003 8.15 In ______ 003 1 8.19 ------------------------------------------- In, c_____ 004 7. 11 c_______ ______ 1. o8 c _____________ 1 7. 14 __________________________________________ _ 

1 Very wonk. 
D-326 GEOLOGICAL SURVEY RESEARCH 1 9 61 

Natural state 

25°C ~ 0 

..s::. 

20 15 10 

29 (degrees) Cu (Ka.) 

In 

+ 

c 

5 

FIGURE 403.2.-X-ray diffractometer patterns for clay from sample D heated in an evacuated chamber. In, interlayered 

chlorite-vermiculite; M, muscovite; C, chlorite. 

1956). Weaver (1956, p. 218) does not specifically list 

such a spacing, but he shows the diffractometer pattern 

for a regular interlayered chlorite-vermiculite after 

heating to 550°C. A peak is present at about 20 A. 

100 300 500 700 900 

Temperature (°C) 

FIGURE 403.3.-Differential thermal analysis of clay from 

sample D. 

Differential thermal analyses, figure 403.3, complement the X-ray results. Water is lost so slowly above 

100°C that low-temperature endothermic troughs do 

not appear between 100°C and 200°C. The main endothermic reaction starts at about 500°C and corresponds 

to a slow water loss from chlorite. At about 550°C the 

slope of the peak becomes much steeper. This is probably the temperature at which the relatively strongly 

bonded second layer of water from the vermiculite unit 

is lost. 

The process that formed the regular interlayered 

structure is unknown. The interlayered chloritevermiculite was present in every clay-bearing sample 

investigated through a 350-foot section of rock. Virtually identical material has been described from mine 

workings more than 6 miles away. This material probably extends throughout the evaporite beds of the area 

and, indeed, is probably the most abundant clay mineral 

present. 

REFERENCES 

Bradley, ,V. F., 1945, Diagnostic criteria for clay minerals: 

Am. Mineralogist, v. 30, p. 704--713. 

Earley, J. "\V., Brindley, G. W., McVeagh, W. J., and Vanden 

Heuvel, R. C., 1956, A regularly interstratified montmorillonite-chlorite: Am. Mineralogist, v. 41, p. 258-267. 

Earley, J. W., and Milne, I. H., 1956, Regularly interstratified 

montmorillonite-chlorite in basalt, in Swineford, Ada, ed., 

Clays and clay minerals-proceedings of the 4th National 

Conference on Clays and Clay Minerals, University Park, 

Pennsylvania, Oct. 10-13, 1955: Natl. Research Council Pub. 

456, p, 381-386. 

Grim, R. E., Droste, J .. B., and Bradley, ,V. F., 1960, A mixedlayer clay mineral associated with an evaporite, in, Swineford, Ada, and Franks, P. C., eds., Clays and clay mineralsproceedings of the 8th National Conference on Clays and 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-43.5 D-327 

Clny Minerals, Norman, Oklahoma, Oct.' 11-14, 1959: [Internnt.] Ser. Mons. IUarth Sci., no. 9, p. 228-236. 

I..~lppmann, ll'riedrich, 1954, Uber einen Keuperton von Zaisersweiher bei Mnulbronn: Heidelberger Beitr. Mineralogie u. 

:Petrogrnphie, v. 4, p. 130-134. 

Vivaldi, J. L. M., and MacEwan, D. M. C., 1960, Corrensite and 

swelling chlorite: Clay Minerals Bull., v. 4, p. 173-181. 

'Veaver, C. E., 1956, 'l"'he distribution and identification of 

mixed-layer clays in sedimentary rocks : Am. Mineralogist, 

v. 41, p. 202-221. 

404. WEATHERING OF PERIDOTITE, SOUTHWEST OREGON 

By PRESTON E. HoTZ, Menlo Park, Calif. 

In northwest California and southwest Oregon deposits of ferruginous nickel- and cobalt-bearing lateritic 

residual soil fonned by deep weathering of peridotite 

occupy terraces on steep slopes and some broad, essentially flat, summits. Most of the deposits have an 

area of less than 100 acres, and the largest are not much 

more than 400 acres in extent. Soil depths commonly 

are 10 to 20 feet; in some places exploration has shown 

thicla1esses on the order of 40 to 60 feet, and in extremely localized areas drill hole. depths of 100 feet 

have been attained. 

Samples of the residual soil, weathered bedrock, and 

fresh peridotite were obtained from an exploratory ex124" 

,...-, 

"' '-.... 

--, 

I 

l----, 

DOUGLAS I _____ «, 

122" 

0 Roseburg 

I ( 

r' Nickel 

X Mountain r-

-, , .... ,. ............ , 

COUNTY / I 

I \ /"' 1,. ............ _ -.," --- I 

"' JOSEPHINE I I 

Grants Pass 0 1 I 

... \ X 5~~~; r I 0 Medford I 

Mountain! 1 

COUNTY I OREGON I --------- CALIFORNIA 

124" 122" 

42" 

FIGURE 404.1.-Index map showing location of Eight Dollar 

Mountain, Josephine County, and Nickel Mountain, Douglas 

County, Oreg. 

ca vation at Eight Dollar Mountain, Josephine County, 

Oreg., and from the open-pit 1nine of the Hanna Ore 

Company at Nickel Mountain, Douglas County, Oreg. 

(fig. 404.1). The soil sections which were sampled are 

summarized below. 

Section at Eight Dollar M o~tntain 

[Numbers correspond to analyzed samples tn table 404.1] 

Top of cut. 

8 .. Firm red soil with iron oxide pellets and some vege- Feet 

tal materiaL----------------------------------- 1 

7. Reddish-yellow soil with streaks of red____________ 1. 8 

6. Yellowish-orange compact soil; some fragments of 

thoroughly weathered peridotite________________ 2. 7 

5. Mottled reddish-brown and yellowish-orange compact 

soil with some black mottling___________________ 2. 7 

4. Yellowish-brown soft granular saprolite with greenish and black mottlings and some paper thin quartz 

veinlets --------------------------------------- 1.8 

3. Yellowish-brown soft granular saprolite with greenish and black mottlings and some paper thin quartz 

veiulets --------------------------------------- 2.8 

2. Weathered peridotite; yellowish-brown soft weathered selvages as much as 2 iu. thick with paper 

thin quartz veinlets surrounding cores of nearly 

fresh rock------------------------------------- 4.2 

Bottom of cut. 

1. Sample of fresh peridotite from adjacent exposure. 

Section at Nickel Mountain 

[Numbers correspond to analyzed samples tn table 404.2] 

Top of cut. 

5. Loose red soil with iron oxide pellets and some vege- Feet 

tal materiaL___________________________________ 2 

4. Yellowish-orange compact soil with few fragments of 

qnartz veinlets; some garnierite veinlets________ 2 

3. Yellowish-orange compact soil; more quartz veinlets 

and garnierite---~----------------------------- 3 

2. Yellowish-brown soft saprolite, veinlets of quartz 

and garnierite (not in sample), grading downward 

into partly weathered peridotite with cores of fresh 

rock surrounded by weathered selvages_________ 2 

Bottom of cut. 

1. Composite sample of fresh peridotite from central 

parts of partly weathered blocks. 
D-328 GEOLOGICAL SURVEY RESEARCH 19 61 

The fresh rock in both area.s is slightly serpentinized 

enstatite peridotite composed of olivine (70 to 80 percent), enstatite with microscopia lamellae of exsolved 

diopside ( 10 to 20 percent), and accessory chromite 

( 1 to 2 percent), magnetite dust, and serpentine. The 

rock from Eight Dollar Mountain contains approximately 12 percent serpentine, and the sample from 

Nickel Mountain approximately ·5 percent. 

Where the peridotite is weathered, the olivine is 

almost completely destroyed. · Pyroxene is less susceptible to weathering and crystal fragments persist 

throughout the soil zone, though in decreasing amounts 

from the base to the topmost layer. Chromite, in contrast, apparently is little affected by the weathering, 

for the amount increases in successively higher samples 

of the soil. Secondary iron minerals, including 

goethite and amorphous material, are the most abundant constituents of the residual zone. A member of 

the montmorillonite group, chlorite, and talc were 

identified in the clay-size fractions of the soil by X-ray 

spectrometer. In the red upper layer montmorillonite 

decreases markedly and chlorite predominates. Finegrained to microcrystalline secondary quartz films and 

veinlets deposited in fractures in·the weathered bedrock 

are broken up and incorporated in higher parts of the 

TABLE 404.1.-Chemical analyses of peridotite and overlying 

residual soil at Eight Dollar Mountain, Oreg. 

[Analysts: PaulL. D. Elmore, Joseph I. Dinnin, Samuel D. Botts, and Marvin D. 

Mack. Samples were analyzed by rapid rock analysis methods similar to those 

described by Shapiro and Brannock (1956)] 

2 3 4 8 

--------------

Si02-------------------- 43.0 32.5 31.5 35.1 21.4 15.6 18.5 21.4 

Ah03--------- ---------- 1. 6 3.8 3. 9 3. 5 4. 7 6. 4 6. 9 9.1 

Fe203-- ---------------- 1.4 29.6 34.5 38.6 49.1 56.1 52.2 47.3 

FeO -------------------- 6. 7 1.9 . 93 .12 . 20 .14 .68 . 72 

MgO _____ -------------- 43.1 15.9 12.4 4. 7 3.3 2.1 1.7 4.1 

CaO _ ------------------ 1.4 1.5 1.4 . 72 .42 .30 .05 .32 

Na20 ------------------- .02 .04 .07 . 04 .04 .06 . 07 .10 

K20 ____ ---------------- .02 . 02 .02 .02 .04 .06 . 05 .13 

H20 -------------------- 2.4 11.3 12.1 13.6 15.9 15.9 16.6 13.4 

Ti02- _ ----------------- .03 .06 .06 . 04 .10 .12 .12 . 23 

P20~- _- ---------------- . 01 .02 .02 .04 .06 .07 .06 .11 

MnO ------------------- .14 . 24 . 30 . 46 .44 . 25 . 25 .28 

C02-------------------- .26 .14 .14 . 18 . 21 .27 . 24 . 21 Cr20a- _________ , _______ .36 1.1 1.1 1.2 2. 4 1.8 2.1 2.0 

CoO ___ -----_---------_ .02 .04 '04 .07 .14 .14 .13 .07 

NiO ---- ___ ------------- .37 1.9 2.2 2.0 2.0 1.8 2.0 1.4 

----------------- Total (rounded) __ 101 100 101 100 100 101 101 101 

1. Fresh peridotite. 

2. Weathered peridotite. Blocks of peridotite with soft weathered selvages as much 

as 2 inches thick. Few very thin seams of garnierite and quartz; 13.6 to 17.8 feet. 

3. Yellowish brown soft but granular saprolite with greenish and black mottlings 

and some thin platy quartz veinlets; 10.8 to 13.6 feet. 

• 4. Same as 3; 8.2 to 10.8 feet. 

5. Compact mottled reddish brown and yellowish orange lateritic soil with some 

black mottling; 5.5 to 8.2 feet. 

6. Compact yellowish orange lateritic soil with some fragments of thoroughly weathered peridotite; 2.8 to 5.5 feet. 

7. Reddish yellow lateritic soil with streaks of red; 1 to 2.8 feet. 

8. Firm red lateritic soil with iron oxide pellets, and some vegetal material; 0 to 1 foot. 

TABLE 404.2.-Chemical analyses of peridotite and overlying 

residual soil at Nickel Mountain, Oreg. 

[Analysts: Paul L. D. Elmore, Joseph I. Dinnin, Samuel D. Botts, and Marvin D. 

Mack. Samples were analyzed by rapid rock analysis methods simUar to those 

·describP.d by Shapiro and Brannock (1956)] 

2 3 4 

Si02---------------- 42. 8 71. 7 32. 2 ·26. 2 38. 4 

AbOa-------- _- _- ____ 1. 1 1.4 4. 9 7. 3 8. 4 

Fe20a--------------- .8 14. 4 38. 7 46. 8 31. 3 Feo ________________ 6. 8 14 . 45 . 29 1.3 MgO _____ --- ________ 45. 7 3. 9 7. 0 2. 1 6. 8 Cao ________________ . 90 12 1.0 . 24 . 58 N a20 _______________ . 03 . 02 . 07 . 08 . 26 K2

0 ________________ . 01 . 02 . 02 . 09 . 24 H2

0 ________________ 1.6 5. 5 11.9 13. 3 8. 0 

Ti02---------------- . 02 . 03 . 08 . 20 . 32 

P206---------------- . 02 . 01 . 05 . 12 . 20 

MnO _____ -- ----- _ --- . 12 . 20 . 48 . 43 . 49 

C02 ______ --- _______ - 12 17 . 24 . 28 17 

Cr20a- - ------- _- --- - . 45 . 59 1.1 1.3 1.5 CoO ________________ . 02 . 03 . 06 . 08 . 06 NiO ________________ . 36 1.5 2. 3 2. 2 1.5 

Total 

(rounded) ___ 101 100 101 101 100 

1. Composite sample of fresh peridotite from central parts of partly weathered blocks. 

2. Soft, weathered peridotite with veinlets of quartz and garnierite; 8 to 10 feet. 

3. Compact, yellowish qrange lateritic soU with remnants of quartz veinlets, some 

garnierite-rich streaks; 5 to 8 feet. 

4. Same as above, with fewer quartz veinlets; 3 to 5 feet. 

5. Loose red lateritic soil with iron oxide pellets and some vegetal material; 1 to 3 feet. 

soil as the weathered zone gradually descends with time, 

although much of the quartz is leached away in the 

upper zones. At Nickel Mountain garnierite commonly 

occurs in veinlets associated with secondary quartz, but 

at Eight Dollar Mountain it is· only rarely seen, as 

paper-thin films. No other nickel minerals have been 

recognized, and it is assumed that nickel and cobalt are 

incorporated in the lattices of the secondary iron 

minerals and the clays. 

Chemical analyses of samples from Eight Dollar 

Mountain and Nickel Mountain are presented in tables 

404.1 and 404.2, and the variations in composition are 

illustrated in figures 404.2 and 404.3. 

Large quantities of MgO released by decomposition of 

olivine and enstatite are lost by removal in groundwater solutions, but MgO persists through the soil 

zones due in part to enstatite, which resists complete 

destruction, and in part to the formation of clay 

1ninerals. CaO, which increases slightly in the first 

weathering stages, parallels the decrease of MgO. 

Probably most of the CaO is contained in the exsolved 

diopside lamellae in the enstatite. SiOz releas~d by 

breakdown of the ferromagnesian minerals also is lost 

by removal in solution, but to a lesser extent than MgO. 

Some of the Si02 recombines with MgO, Fe203, and 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293'-43.5 

Sample 1 2 3 4 5 6 7 8 

MgO e, ,---A--v--..A---,~~,.---J'---,~r't 

10,000 ~--~~~,~------------------------------------------------~----------------------- .... , -

----::.., ---- '::---,.;...&. 

,/r- ~ ~ 1000 ~~F~e~0~------------------------~/~/--------------------------~~~~---------------------~1 

10 

NiO A 

/ 

/ 

Cr20 30,..... ...-

MnO _'It--

CoO 

.... ..... ..... 

/ 

.., / 

---

...... 

/ ...... 

_.,' .., _,.. 

- - ----

/ ......._ ~ 

"""- /1 / 

_\, .,¥ Mnn ............... j 

- --~ -

1 _l I 1 1 _l _l J 

18 16 14 12 10 a 6 4 2 0 

DEPTH BELOW SURFACE, IN FEET 

FIGUJut 404.2.-l\ioleculnr proportions, computed from analyses given in table 404.1, of peridotite and overlying residual 

soil at Eight Dollar Mountain, Oreg. 

6044~h 0-61-22 
D-330 

10,000 

1000 

0 

0 

0 

~ 

X 

z 

0 

i= 

0:: 

0 

a.. 100 0 

0:: 

a.. 

0:: 

<( 

_J 

~ 

u 

UJ 

_J 

0 

~ 

10 

Sample 1 

MgO 

Si02 

Feo 

/ 

H20 \ 

\ 

NiO 

MnOx.....- ..-

GEOLOGICAL SURVEY RESEARCH 1 9 6 1 

/ 

\ 

\ 

\ 

/ 

\ 

\ 

\ 

\ 

\ 

/ 

/ 

/ / 

/ 

\ I 

\ I 

' I 

\I 

I\ 

I \ 

'....-/ 

\ 

\ 

\ 

\ 

I 

I 

I 

I \ L.--- J.---y/ 

\ 

\ 

---

2 3 

CoO ---

/ 

/ 

/ 

10 8 6 

DEPTH BELOW SURFACE, IN FEET 

4 5 

4 2 0 

FIGURE 404.3.-Molecular proportions, computed from analyses given in table 404.2, of peridotite and overlying residual 

soil at Nickel Mountain, Oreg. 
SHORT PAPERS IN THE GEOL'OGIC AND HYDROLOGIC SCIENCES, ARTICLES 293.--4,3,5 D-331 

Al:l03 to form clay minera.Is, and some is reprecipitated 

as quartz. Iron, also released by destruction of the 

ferromn,gnesian m inern.ls, is oxidized from. the ferrous 

to the ferric state and concentrated in the soil zone 

.beneath the brick-red upper htyer. NiO concentrates 

similarly to Fe:!OH. The relative concentration of iron 

and nickel is due to the removal of l\1g0 and Si02. 

l\1n0 and CoO are also concentrated in the soil zone 

beneath the upper layer. Al!03, one of the less soluble 

constituents, increases continuously relative to other 

constituents in successively higher samples of the soil. 

Cr:l03 and TiO:l show a persistent increase throughout 

the soil zone. Ti02, possibly the most insoluble constituent, may indicate (by its residual concentration) 

the absolute quantities of other components removed. 

It would be a more reliable indicator, however, if its 

content .in the fresh peridotite were not so low. 

In the upper 2 to 4 feet the trends are, in general, 

reversed except for Al203, N a20, 1(20, and Ti02. 

Fe:JOa clecren,ses slightly and FeO increases, possibly 

due to reduction from Fe+3 to Fe+2 under the influence of 

organic matter. There is also a decrease in total iron, 

possi bTy due to removal of ferrous iron by rain water 

that contains dissolved C02 in the soil zone; but presumably solution of Fe+2 is slower than the reduction 

TABLE 404.3.-Quantitative spectrographic analyses (in percent) 

of peridotite and overlying residual soil at Eight Dollar Mo'untain, 

Oreg. 

[Annlyst: Sol Bormnn. Sample numbers correspond to those in table 404.1) 

1 2 3 4 5 6 7 8 

-------------- Cu ____________ 0.()007 0.013 0.0098 o. 0090 0.011 o. 015 0. 010 0.012 v _____________ .0051 . Oll . 012 .010 .020 . 016 .020 .023 Sc. ____________ .0017 .0042 .0054 .0054 .0076 .0076 .0067 .0066 

Sr ------------- <.0002 <.0002 <.0002 <.0002 <.0002 <.0002 <.0002 .0010 Ba. __ e_ ________ <.002 .002 .002 .003 .003 .003 .003 .006 

of Fe+3 to Fe+2. The decrease in ferric iron is accompanied by a decrease in NiO and CoO. In this zone 

there is an increase in MgO, CaO, and Si02 , which probably is the combined effect of re~idual concentration 

due to loss of iron and dehydration at the surface, but 

possibly represents a real concentration caused by 

accumulation of litter and humus from plants growing 

on the soil and concentrating some elements, as recently 

emphasized by Lovering ( 1959) for silica. 

Quantitative spectrographic analyses of peridotite 

and residual soil at Eight Dollar l\1ountain are given 

in table 404.3. Cu, V, and Sc incr-ease several fold in 

the soil zone. Sr and Ba. concentrate in the topmost 

zone .. 

In comparison with laterites ·formed from ultramafic 

rock under tropical weathering conditions in Cuba 

(Leith and Mead, 1915, p. 39; l\{ohr and Van Baren, 

1954, p. 1.46), the Philippines (Frashe, 1.941, p. 298), 

and French Guinea (l\1illot and Bonifas, 1955, p. 6), 

the residual soils in southwest Oregon have a notttbly 

higher content of Si02 and MgO, lower Fe20s, and do 

not attain as high an Al20 3 concentration. 

REFERENCES 

Frashe, D. F., 1941, Origin of the Surigao iron ores : Econ. Geol. 

v. 36, p. 280-305. 

Leith, C. K., and Mead, \V. J., 1915, Metamorphic geology: New 

York, Holt and Co., 337 p. 

Lovering, T. S., 1959, Significance of accumulator plants in 

rock weathering: Geol. Soc. America Bull., v. 70, p. 781-800. 

Millot, Georges, and Bonifas, Marthe, 1955, Transformations 

isovolumetriques dans les phenomenes de lateritisation et 

bauxitisation: Alsace-Lorraine, Serv. Carte Geol., B. T. 8, 

f. 1, p. 3-20. 

Mohr, E. C. J., and Van Baren, F. A., 1954, Tropical soils; a 

critical study of soil genesis as related to climate, rock and 

vegetation: New York, Interscience Publishers, 498 p. 

Shapiro, Leonard, and Brannock, W. W., 1956, Rapid analysis of 

NOTE: ncsults havo an overall accuracy of ±15 percent except where only one silicate rocks: U.S. Geol. Survey Bull. 1036-C, p. 19-56, 

digit Is reported. Looked for but not found; Os, Ir, Pt, Re, Cd and Y, Rh. (revision)· 
D-332 GEOLOGICAL SURVEY RESEARCH 1 9 61 

405. GEOCHEMICAL SURVEYING FOR GOLD VEINS IN THE ATLANTIC DISTRICT, WYOMING 

By RICHARD W. BAYLEY and WILLARD W:JANEs, Menlo Park, Calif., and Denver, Colo. 

The ore veins in the Atlantic gold district, Wyoming, 

contain chiefly quartz, arsenopy6te, pyrite, and gold. A 

simple, though not infallible, method for finding them 

is to explore close to the belts of intrusive rocks that 

trend east-west across the district. Nearly all of the 

gold produced from lodes came from mines located 

along belts of. intrusive metagabbro (fig. 405.1). But 

114" 104" 

p£s 

,---------,45" 

I WYOMING II 

I I· 

I \,, '·-·'"J FREMONT l 1 \ !couNTY \ I l~ __ j 

I I L_ ___________ _j 40" 

T 29 N INDEX MAP 

0 6 MILES 

FIGURE 405.1.-Generalized geologic map of the Atlantic gold 

district. Stippled pattern, main metagabbro belts ; ® major 

gold mines ; X, some other mines and prospects; p£S, Precambrian metasedimentary and metavolcanic rock.s, undifferentiated; p£g, Precambrian granite intrusive into p£s; P, overlapping Paleozoic sedimentary rocks. Inserts indicate location of the district and area of the detailed geologic map 

(fig. 405.2). 

much of the district underlain by the metagabbro belts 

is soil covered, and although the soil has been trenched 

to the bedrock at many places, large areas of potentially 

productive ground remain untouched. 

Among methods tried for locating soil-covered gold 

veins, magnetic and self-potential electrical surveying 

over known veins gave very discouraging results. Soil 

analysis for arsenic along a few traverses, however, indicates that this method may be successful. 

Figure 405.2 shows the geology of the test area, the 

traverse lines, and graphical representations of the 

varying arsenic content of the soil along the traverses. 

Soil samples of about 2 ounces each were taken by 

shovel from depths of 4 to 6 inches at intervals of 50 

feet or less along each traverse. The arsenic determinations were made in the field by Janes using the Gutzeit method as modified by Almond (1953, p. 1766). 

The metagabbro, andesite, and graywacke contain 9 

to 22 ppm (parts per million) arsenic; the soil over 

them contains 5 to. 20 ppm. Samples representing a 

low-grade quartz vein, ore (1.5 oz per ton gold), and 

an arsenopyrite-bearing dacite contained 600, 350, and 

160 ppm arsenic. 

Traverses A, B, and C (fig. 405.2) extend uphill from 

soil-covered graywacke northward across part of the 

northern metagabbro belt. In general, the soil cover 

diminishes over the topographically higher areas. 

Arsenic anomalies of 50 to 60 ppm occur in thin soil 

over areas where numerous small quartz veins cut the 

metagabbro. The gradients of arsenic concentration 

are steep on the uphill sides of the anomalies but tend 

to be more gentle on the down slope, suggesting that the 

arsenic, and probably the total anomalies as well, are 

slightly displaced downhill. 

TraverseD was made in the bottom of a valley that 

drains into what was rich placer ground. The arsenic 

profile appears to reflect the close proximity of the 

bedrock, which crops out on the east side of the valley. 

The peak concentration, about 30 ppm, is very close to 

bedrock exposed to the east, but no veins are exposed. 

The results of this preliminary test seem very encouraging. In the test area the method has delineated 

a belt of rocks at least one-half mile long worthy of 

closer examination. No attempt was made to deterInine the gold content of the veins in this belt. That 

they are gold-bearing is almost certain inasmuch as 

gold is consistently associated with arsenopyrite in this 

district. 

REFERENCE 

Almond, Hy, 1953, Field method for determining of traces of 

arsenic in soils: ·Anal. Chemistry, v. 25, p. 1766-1767. 
A 

~ 

;:l...u_As 

20 

0 

A A' LL

As 

~: B B' 

D' 

Graphs showing quantities of arsenic in soil along traverses, in parts per million 

0 1000 2000 3000 FEET 

EXPLANATION 

[E] ~>- 1-0:: t -~~ 

I t"·~·j i Flathead sandstone ::E 

+ eovered by alluvium tj 

~~~~ Metagabbro 

-~ ID 

Meta-andesite ::E 

tj 

w 

[ 

Sehist, grvwaeke, 

and conglomerate -------J-...1--"-

Contaet 

Dashed where appToximately /.ocated, 

barbed where concealed 

.=-.:::----.::--::: 

Fault or shear zone 

60..---t---- Antieline 

SJwwi11f} trace of axial pla'M and 

beari11g and plu11ge of axis 

.....<" 80 

Strike and dip of beds 

~ 

90 

Strike and dip of vertical beds 

~ 

Strike and top direction 

of graded beds 

-;;5 Strike and dip of foliation 

~ 

Mine 

~ 

Shaft 

A~ --A' 

Line of geoehemieal traverse, 

showing arsenie anomaly. 

Size of eirele roughly 

proportional to anomaly 

FIGURE 405.2.-Geologic map of part of the Atlantic gold district, Fremont County, Wyo. 

U1 

~ 0 

~ 

8 

"'d 

> "'d 

tz:j 

~ 

UJ 

z 

~ tz:j 

c 

tz:j 

0 

8 

0 

lo.,-4 

0 

> z 

I:' 

~ I:' 

~ 

0 

~ 

0 

c 

~ 

0 

w 

Q 

tz:j 

~ tz:j 

~UJ 

> 

~ 

8 

~ tz:j 

UJ. 

~ 

(0 

c.:~ 

r 

~ 

c., 

6t 

t1 

ck 

C-1:) 

C-1:) 
D-334 GEOLOGICAL SURVEY RESEARCH 19 61 

406. GEOGRAPHIC DISTRIBUTION OF MAJOR CONSTITUENTS IN STREAM WATERS OF THE WESTERN 

CONTERMINOUS UNITED STATES 

By C; E. RoBERSON, Menlo Park, Cali£. 

Stream waters o£ the western conterminous United 

States have chemical characteristics that reflect their 

geologic and climatologic environments. Figure 406.1 

is a graphic presentation o£ the chemical character o£ 

selected streams in the western States. The annual 

average quality at each station shown on the map is 

represented by two semicircles. The semicircle on the 

left shows the percentage com.position o£ the principal 

anions (bicarbonate, sulfate, and chloride), that on the 

right depicts the cations (calcium, magnesium, ·and 

sodium plus potas$ium). Each individual wedge 

represents the percentage o£ a particular anion or cation 

based on equivalents per million. The size o£ the circle 

indicates the concentration o£ solutes in tons per acrefoot ( t per ac-ft). 

The line drawn on the map labeled HC03-S04 emphasizes what is believed to be the most prominent 

characteristic noted in the ·distribution o£ the major 

elements. Generally, streams west o£ the line have hicarbonate as the principal anion, whereas those to the 

east have sulfate. Individual streams differ from the 

general pattern shown, but the exceptions among rivers 

for which detailed records are available are few. For 

example, parts o£ the Gila River in Arizona and the 

Pecos River· in New Mexico have waters in which 

chloride is the major anion. Streams in mountainous 

areas have large percentages o£ bicarbonate, but become 

sulfate-dominant in their lower courses. 

0£ the sampling sites shown on figure 406.1 the 

Feather River in California and the Pecos River in. 

southeastern New Mexico illustrate extremes in percentage of bicarbonate. In the Pecos River, bicarbonate 

represents only about 3 percent o£ the total anions, but 

in the Feather River it makes up about 84 percent of the 

anions. 

Calcium content is roughly equivalent to bicarbonate 

content in most rivers for which adequate long-term 

records are available. In many river waters calcium is 

the most abundant cation, and in several it makes up 

more than hal£ of all the cations. The gypsiferous de-. 

posits in the Pecos basin are responsible for large 

amounts of calcium as well as o£ sulfate in the water o£ 

that river. There is no striking pattern in the geographic distribution o£ magnesium. 

The highest concentrations of chloride in water o£ 

major streams studied are found in parts o£ the Gila and 

Pecos River basins. That the chloride in these waters 

is a result of solution of well-known halite deposits is 

indicated by the presence of nearly chemically equivalent amounts o£ sodium and of chloride. On the other 

hand, sodium concentrations are higher than chloride 

concentrations in most of the other rivers, indicating 

that sodium chloride is generally not ·the main source o£ 

sodium. Sodium and chloride are relatively more 

abundant in the waters of streams east o£ the line than 

in waters west of the line. 

These deviations from chemical characteristics generally associated with many North American streams 

where bicarbonate is the principal anion (Clarke, 1924, 

p. 119), reflect a complex interaction of geologic and 

climatologic factors. The climatic factors include 

smaller amounts o£ precipitation in the eastern part o£ 

the area in figure 406.1, as well as higher rates o£ evaporation. 

At a few places sulfate comes from bedded gypsum 

deposits, such as those in the basin of the Pecos River. 

Gypsum is doubtless a contributor of sulfate in other 

areas; however, minerals other than gypsum appear to 

be partly responsible for some high-sulfate waters such 

as the Powder a11d Bighorn Rivers in Wyoming and 

Montana, and some of the strea-ms in eastern Utah and 

western Colorado. Here the calcium is notably deficient 

relative to sulfate rather than in balance as might be 

expected i£ only gypsum were being dissolved. 

Waters in areas east of the line on figure 406.1 commonly have maximum sulfate concentrations ranging 

from 100 to more than 1,000 ppm (parts per million). 

Certain exceptions in Colorado, New Mexico, Arizona, 

and Utah show the effects of higher elevations and 

greater relief which give rise to greater rainfall. Unusual geologic conditions might also affect these 

streams. 

REFERENCE 

Clarke, F. W., 1924, The data of geochemistry: U.S. Geol. Survey 

Bull. 770, 841 p. 
SHORT PAPE'RS IN THE GEOLOGIC AND HYDROLOGIC SCIEN9ES, ARTLCLES 293t-4,35 

HC0: +CO~~Cn 

so ~ Mg 

Cl-' Nn+K 

0.0 I to 0. I 0.1 to I ""·cs·o I to 3 

1/oc-11 

l!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!J!!!!OI;;;0====-201'!0!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!301;;;0====;;;j400 MILES 

D-335 

.l!"'IOUUE 406.1.-Mnp showing general chemical character of water in major rivers of the 11 western States. Concentration of solutes is given in tons per acre-foot (t per ac-ft). 
D-336 GEOLOGICAL SURVEY RESEARCH 19 61 

407. INTERACTION OF ANHYDRITE WITH SOLUTIONS OF STRONTIUM AND CES:IUM 

By IRVING MAY, MARIAN ScHNEPFE, and CHARLES R. NAESER, Washington, D.C. 

Storage or disposal of high-level radioactive waste 

solutions in cavities in salt deposits is being considered 

by the responsible government agencies. Strontium-90 

and cesium-137 are the most troublesome wasw nuclides 

derived from reprocessing radioactive fuels. The interaction of these elements with anhydrite has been studied 

because anhydrite is commonly associated with the salt 

in evaporite deposits. 

Anhydrite is one of the chief carriers of strontium in 

evaporite deposits and contains as much as 0.65 percent 

strontium (Noll, 1934); therefore, anhydrite might be 

expected to react with strontium. Celestite (SrS04) is 

appreciably less soluble in water than is anhydrite, its 

solubility at 20° C being 0.01 g per 100 ml compared to 

0.30 g per 100 ml for anhydrite. Anhydrite would not 

be expected to react with cesium solutions. 

DESCRIPTION OF SAMPLES 

Initial experiments were conducted with natural anhydrite obtained from the U.S. Gypsum Company. An 

X-ray analysis by Daphne Ross of the 'Geological Survey showed that this anhydrite contained more than 10 

percent gypsum; a Penfield water determination showed 

it to contain 6.24 percent water, corresponding to 30 percent gypsum. Confirmatory experiments were later 

conducted using a purer sample of anhydrite; this 

sample was from a core from Hutchinson County, 

Kans., obtained through the courtesy of W. B. Heroy, 

Geotechnical Corp., Dallas, Tex., and H. L. Parker, Oak 

Ridge National Laboratories, Oak Ridge, Tenn. The 

sample contained 0.52 percent water, corresponding to 

2.5 percent gypsum. 

Synthetic anhydrite samples were prepared by heating reagent grade calcium sulfate either at 900° C for 1 

hour or at 400° C for 24 hours (Kelley and others, 

1941). Complete conversion to anhydrite was con· 

firmed by X:-ray analysis. Most of the experimental 

work was done with synthetic anhydrite because of its 

greater purity. 

EXPERIMENTAL WORK 

COLUMN EXPERIMENT 

A column experiment was run first to determine 

whether and how anhydrite takes up strontium. A 

sample of the U.S. Gypsum anhydrite ( 40 to 60 mesh) 

weighing 40 g was packed into a column with an inside 

diameter of 12 mm. ..A. solution containing 100 ppm 

(parts per million) of strontium and a trace of free 

nitric acid as a stabilizer was passed over the anhydrite 

by downward flow at a rate of 5 ml per hr. The strontium and calcium contents of the eluates, collected in 

four fractions, were determined with the flame photometer (table 407.1). 

TABLE 407. L-Column experiment with strontium solution and 

anhydrite 

Eluate fraction (ml) 

Q-5 ________________________________ _ 

5-15 l_- ---------------------------- 15-25 _____________________________ _ 

25-35 _____________________________ _ 

1 Column stood over weekend. 

Strontium 

(ppm) 

37 

18 

33 

28 

Calcium 

(ppm) 

450 

430 

400 

400 

The strontium in the effluent ranged from 18 to 37 

percent of the initial concentration. The strontium 

data do not support an exchange or absorption reaction. 

The calcium content of the effluent is a measure of the 

extent of solution of the sample. 

Attempts to improve contact between solution and 

anhydrite by the use of finer material resulted in poor 

flow rates and channeling. Column studies were discontinued, therefore, in favor of batch experiments. 

BATCH EXPERIMENTS 

Strontium solutions were treated with anhydrite in 

stoppered flasks. Data for these experiments are shown 

in table 407 .2. Most of these suspensions were stirred 

continuously with magnetic stirrers, which raised solution temperatures to about 40° C. Experiments 8 and 8a 

were performed on a magnetic-stirrer hot-plate to insure a temperature exceeding_ the transition point of 

40° C, below which anhydrite suspended in water is 

converted to gypsum; these conditions thus ruled out 

the conversion of gypsum to anhydrite during the course 

of the experiment. 

Three aliquots of resultant solutions were filtered and 

treated with fresh anhydrite to determine additional 

depletion of strontium from solution. 

The rate of depletion of strontium from solution was 

also determined at room temperature. Anhydrite 

samples were agitated with strontium solutions on a 

mechanical shaker for periods ranging from 1 hour to 

35 days. The results are shown on figure 407.1. 
SHORT PAPE'RS IN THE GEOLOGIC. AND HYDROLOGIC SCIENCES, ARTICLES 293,.....43,5 D-337 

TABLE 407.2.-Batch experiments, strontium solutions with anh:!Jdrite 

Contacting solution Final solution 

Approximate Sample Contact time temperature 

Experiment 

'l'ypeor 

anhydrite t weight Concentration (hours) (degrees Strontium 

(grams) Volume pH or strontium Centigrade) pH (parts per Calcium (parts (milliliters) (parts per million) per million) million) 

l __________ A 1 100 1.7 100 18 40 ---------- 22 760 2 __________ B 1 100 1.7 100 22 40 2. 0 18 680 

95 40 2. 1 13 700 3 __________ B 1 100 5. 4 100 22 40 10. 5 31 420 4 __________ B 1 100 (2) 100 23 4.0 10. 8 15 940 5 __________ B 1 100 (8) 100 23 4:0 1.0 7 1, 100 6 __________ B 5 100 (4) 100 23 4:0 11. 2 34 1, 600 7 __________ B 1 100 (4) 500 23 40 10. 7 33 2, 300 8 __________ B 1 100 (4) 100 19 55 ---------- 20 400 8a _________ B 1 (5) -------- 20 19 55 ---------- 20 375 9 __________ A 1 50 5. 5 100 17 40 8. 1 28 ---------- 9a _________ A 0. 5 6 25 8. 1 28 17 40. 7. 9 23 ---------- 10 _________ c 1 50 5. 5 100 17 40 7. 8 31 ---------- lOa ________ c 0. 5 7 25 5. 5 31 17 40 7. 9 28 ----------

1 A, U.S. Gypsum anhydrite (30 percent gypsum, -35 mesh); B, Synthetic anhydrite; C, Hutchinson anhydrite (-35 mesh), 

s 1 gram Na2S01, no free acid. 

a 1 milliliter H2S04. 

4 No free acid. 

a Entire filtrate, experiment 8. 

c Filtrate from experiment 9. 

7 l!'lltrnte from experiment 10. 

l'o distinguish more conclusively between exchange 

and precipitation mechanisms, a final group of experiments was made in which three different weights of 

synthetic anhydrite were treated for 2 weeks in sealed 

ampoules with strontium and with cesium solutions adjusted to pi:I 7. The ampoules were immersed in a constattt temperature bath kept at 45° C. Mixing was accomplished by thoroughly shaking the ampoules manually several times a day. Data for these experi1i1ents are 

given in table 407.3. 

ANALYTICAL METHODS 

Strontium and calcium were determined with a Beckman DU flame photometer in the column experiment 

(table 407.1) and in batch experiments 1 to Sa (table 

TABT-lD 407.3.-Interaction of strontium and cesium with anhydrite 

[Solution volumes 25 ml, pH 7, 45°C, contact time 2 weeks] 

Weight of 

Anhydrite (g) 

0. 5 

.5 

1.0 

1.0 

1.5 

1.5 

Strontium concentration Cesium concentration 

Initial 

(ppm) 

80 

Final 

(ppm) 

Initial 

(ppm) 

Final 

(ppm) 

33 ----------- -----------

- - - - -·- - - - - - - - - - - - - - - - - 80 80 

80 30 - - - -· - - - - - - - - - - - - - - - - - -

----------- ----------- 80 79 

80 24 - -- - - - - - - - - - _·- - - - - - - - -

----------- --- ------·-.. 80 79 

407.2). A wavelength of 461 mp. and the photomultiplier detector were used; under these conditions 370 

ppm calcium did not interfere with the determination 

of 10 ppm strontium. Calcium was determined at a 

wavelength of 554mp.. 

All other determinations of strontium were made by 

,8-counting techniques using strontium-S9 as a tracer. 

Aliquots of solutions were evaporated in aluminum 

planchets and their activities determined with a GeigerMuller counter. The amounts of calcium dissolved 

during the experiments did not have a significant absorption effect on the ,8-emission of strontium. 

Cesium determinations were made with a scintillation 

counter using cesium-137 as a tracer. 

SUMMARY. OF RESULTS 

Contact of solutions containing 100 ppm of strontium 

with anhydrite resulted in final solution concentrations 

of about 20 to 35 ppn1 strontium. Equilibrium at 40° C 

was apparently achieved in less thali 1 day (table 407.2, 

experiments 2, Sa, 9a, and lOa). 

At room temperature, two weeks were required for 

equilibrium to be reached in the batch experiments (fig. 

407.1). However, protracted treatment at room temperature is complicated by the conversion of appreciable 

quantities of anhydrite to gypsum, as confirmed by Xray analysis (M. L. Lindberg, oral communication, 

1960). 
D-338 GEOLOGLCAL SURVEY RESEARCH 19 61 

50r-----r-----~----~----~----~----~----~ 

40 

10 

10 20 

DAYS OF CONTACT 

30 

FIGURE 407.1.-Rate of reaction of strontium solutions with 

anhydrite. Experiments conducted at room temperature using 

0.7907 g of synthetic anhydrite in 50 .ml of solution containing 

50 ppm of strontium. 

The mechanism of the reaction of strontium solutions 

with anhydrite appears to be mainly precipitation of 

strontium sulfate, the sulfate being furnished by the 

solution of some anhydrite. Sorption reactions are not 

important mechanisms, as indicated by several experiments where the reduction of strontium concentration in 

solution showed little dependence on increasing quantities of anhydrite. Thus, passage through a column 

of 40 g of anhydrite did not yield breakthrough data 

typical of sorption reactions. Experiments 8 to lOa of 

table 407.2 and the data for strontium in table 407.3 

also support this conclusion. 

As anticipated, no significant reaction takes place between cesium solutions and anhydrite. 

From these experiments, strontium in excess of 35 

ppm in solutions as ·acid as pH 1.7 could be expected to 

be immobilized on contact with evaporites containing 

anhydrite. In the absence of phosphate or carbonate 

ions which form extremely insoluble strontiun1 compounds, it is unlikely that the strontium solutions would 

be deconta.minated to a level below 10 to 20 ppm strontium. No significant change in cesium concentrations 

would occur. 

Anhydrite in salt deposits could cause local concentrations of strontium derived from radioactive waste 

solutions. These concentrations, however, would not 

necessarily interfere with the storage of waste solutions 

in salt deposits. 

REFERENCES 

Kelley, K. K., Southard, J. C., and Anderson, C. T., 1941, 

Thermodynamic properties of gypsum and its dehydration 

products: U.S. Bur. Mines Tech. Paper 625, p. 6. 

Noll, ·w., 1941, Geochemie des Strontiums mit bemerkungin zur 

Geochemie des Bariums: Chemie der Erde, v. 8, p. 507. 

408. SOME ALTERATION REACTIONS IN THE SYSTEM Na20-Al20a-SiO:r-H20 

By J. J. REMLEY, CHARLES MEYER, and D. H. RrcHTER, Denver, Colo., University of California, Berkeley, 

Calif., and Hawaii Volcano Observatory, Hawaii 

Hydrolysis equilibria involving albite and its decomposition products in an aqueous chloride environment 

at elevated temperatures and pressures have been 

investigated. Sealed platinum tubes contained in rod 

bombs were used in the experimental procedure. The 

bombs were rapidly quenched at the end of each run. 

At high temperatures the reactions observed are the 

alteration of albite to paragonite plus quartz, and the 

decomposition of paragonite to pyrophyllite in the 

presence of quartz according to the equations 

3/2 NaAlSiaOs+ H+~l/2 NaAlaSia010 (0H) 2+3Si02+ 

Na+ (1) 

N aA13SiaOlo ( OH) 2 + H+ + 3Si02~3/2 Al2Si401o ( OH) 2 

+Na+ (2). 

At lower temperatures, the corresponding reactions 
SHORT PAPE:RS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293t-4,3.5 D-339 

n.re the decomposition of albite to montmorillonite.and 

the alteration of montmorillonite to kaolinite. Thereactions n1ay be illustrated by the following equations, 

although the composition of montmorillonite involved 

in the equilibria has not been established: 

1.17 N aAlS.iaOs +I-I +~0.5 N ~.s3Ah33Si3.o701o (OR) 2 + 

1.67 Si02+ Na+ (3) 

3 Nao.asA12.s3Sis.o701o(OH)2+H++3.5 Rz0~3.5 Al2Si2 

O~~(OH)4+4Si02+Na+ (4) 

The silica phase that crystallizes spontaneously in the 

lower temperature reactions is generally cristobalite. 

Stability relations are shown on figure 408.1 in terms 

of the molar N aCl/HCl ratio or equilibrium quotient 

of the reaction and the temperature. The relations are 

similar to those found in the system 1{2 0-Al20a-Si0zII::O (I-Iemley, 1959), which is indicated by dotted 

lines on figure 408.1. The concentrations of N aCl and 

I-ICl in the reacted solutions are the principal chemical 

da.tn. derived from the experiments. The concentrations of aqueous silica and alumina are not involved in 

the equilibrimn constants for the above reactions, although they are of interest from the standpoint of min-

~ 500 c( 

0:: 

(.!) 

i= 

z 

UJ 

u 

~400 

UJ 

0:: 

(.!) 

UJ 

c 

~ 

u.i300 

0:: 

:::::> 

~ 0:: 

UJ 

a. 

:=;: 

~ 200 

101 

Quartz present in excess; 15,000 psi total pressure 

102 103 

mNaCI/mHCI 

104 105 

FIGURE 408.1.-Some stability relations in the system Na20-

Ab03-Si0ri-LO as a function of temperature and the 

m NaCl/m HOI ration. Corresponding relations i~ the terms 

of m KCl/m HOI are indicated by dotted lines for the system 

KaO-AhOa-SiOrHaO. 'l'he field of K-mica is between the 

dotted curves, with K-feldspar at higher values of KCl/HCl 

and pyropbyllite and kaolinite at lower values. 

eral solubilities under the given conditions of temperature, pressure, and electrolyte concentration. 

As indicated on figure 408.1, the fields of stability of 

N a-mica and montmorillonite are much narrower in 

terms of the N aCl/HCl ratio than the corresponding 

1{-.mica field in terms of the KCl/HCl ratio in the 

analogous KzO system. Although slightly higher 

alkalijH + ratios are needed to stabilize albite than are 

required forK-feldspar, much higher alkalijH+ ratio~ 

are needed to stabilize paragonite than are required for 

muscovite. At 400° C the equilibrium -quotients for the 

decomposition of 1{-mica and }{-feldspar in the presence 

of excess quartz are respectively 10 1·

35 and 10 2 ·

7. In 

the soda system the values for N a-mica and N a-feldspar 

are respectively 10 2·

25 and 10 3·

0 • The experimental uncertainty for these values is about 10 °· 2• Reproducible· 

data were more difficult to obtain in this investigation 

than with the corresponding 1{20 system, especially 

along the albite hydrolysis curve at temperatures lower 

than about 400° C. This was apparently due to poorer 

crystallization of phases in the reactions, as well as to 

experimental difficulties involved in quenching. 

Experimental decomposition temperatures rather 

than true stability limits, which are probably somewhat 

lower, are shown by broken lines for the sodium montmorillonite and kaolinite (fig. 408.1). The values indicated are for 4m N aCl solutions. In more dilute solutions the decomposition temperatuers are higher because of the increased activity of water under these 

conditions. The temperatures are increased 20° to 30° C 

in water completely free of electrolytes. The decomposition product of the montmorillonite obtained in the 

e~perimental work is a mixed-layer sodium montmorillonite-mica. This phase becomes increasingly rich in 

the mica component at higher temperatures. Also, with 

some paragonite present initially in the charge, montmorillonite is converted largely or completely to sodium 

mica. Mixtures of paragonite and mixed-layer phase 

show much slower conversion to mica, and results are 

generally inconclusive. However, from the foregoing 

evidence it is likely that paragonite is the thermodynamically stable phase over much, and possibly all, of 

the field of formation of the mixed -layer material. 

The n10lar N aCl/HOl ratio for the reactions is related 

to the equilibrium constant by the expression: 

K 'Y±NaCI m NaCI aNa+ 

'Y±aci m ac1 a a+ (5) 

where "Y is the a.ctivity coefficient and a is the activity. 

For reaction (4) water also appears in the expression. 

The experimental data cannot be treated rigoroui!ly 

because of the lack of appropriate thermodynamic information at elevated temperatures and pressmes; how-
D-340 GEOLOGICAL SURVEY RESEARCH 1 9 61 

ever, by analogy with the system K20-Al20a-Si02-H20 

(Remley, 1959), the experimental equilibrium quotients 

probably approximate within a factor of 5 the true 

equilibrium constants of the reactions to temperatures 

of perhaps 350° C or higher. An important point is 

that strong electrolytes such as HCl, KCl, and KOH 

remain quite strongly ionized at moderate temperatures 

(300° to 400° C) and fairly high pressures (1 ,000 

atmospheres). Ionization decreases gradually with increase in temperature, but the three electrolytes are 

affected similarly and are of comparable strength 

under these conditions (Franck, 1956). 

Although the present study involves the use of strong 

acids and electrolytes, the results have general application to geologic processes. The equilibrium constants of 

reactions and the ratios of certain ion constituents 

funda1nentally control mineral stability relations in 

alteration systems regardless of the particular composition or degree of acidity of the altering solutions. However, the amount of reaction, as distinct from the kind 

of reaction, depends upon absolute concentrations or 

the availability of reactants. 

The experimental results are valuable in the interpretation of field relations in hydrothermally altered 

rocks. The decomposition of plagioclase results in the 

formation of kaolinite rather than montmorillonite at 

low Na+jH+ ratios. This agrees with field alteration 

patterns in which argillized wall rock characteristically 

shows dominant kaolinite and lower N a conte~1t closer 

to the vein, and montmorillonite and higher N a content 

farther out. 

The relation of argillization to processes of sericitic 

alteration cannot be evaluated properly until the more 

complex system including CaO has been investigated. 

However, the greater susceptibility of plagioclase, compared with I{ -feldspar, to decomposition by hydrolysis 

is m:>teworthy. The source of potassium in rocks that 

have been hydrothermally altered to sericite was, in some 

rocks, the release of I{+ by the sericitization of orthoclase, 'vhereas in other rocks l{+ was demonstrably added 

but orthoclase was not altered or was only partly altered 

(l\1eyer and Remley, 1959). The formation of sericite 

during the alteration of plagioclase, without the breakdow·n of !\:-feldspar, does not necessarily require alteration by solutions enriched in potassium. Selective decomposition of plagioclase would result in a decrease 

in H + and an increase in the ratio of I{+ /H + as well as 

Na+/H+ in solution. A point in the muscovite field (fig. 

408.1) represents a solution of a given l{+jH+ ratio 

which would undergo a continued diminution of the H+ 

activity as the solution migrates through a plagioclasebearing rock. This would tend to increase the I\:+ /H + 

ratio within the muscovite field and give rise to sericitization of plagioclase, with or without the destruction of 

orthoclase. In some rocks the K+ /H+ ratio might rise as 

high as the I{-feldspar stability field as a result of such 

a process, with possible replacement of plagioclase by 

!(-feldspar. 

On the other hand, at sufficiently low activities of K+ 

relative to Na+ and other cations, montmorillonite 

rather than sericite w~ould be produced; however, stability relations and fields of formation involving n1ontmorillonite and I\:-Na mica, both of which are of variable composition, are not yet defined. 

REFERENCES 

Franck, E. U., 1956, Hochverdichteter wasserdamf-I, Electrolytische leitfahigkeit in KCl-H20 losungen bis 700° C; II, 

Ion dissoziation von KCl in H20 bis 750° C; III, Ion dissoziation von HOI, KOH, und H 2 0 in uberkritischem wasser: Zeitschr. Physik. Chem., v. 8, p. 92-206. 

Hemley, J. J., 1959, Some mineralogical equilibria in the system 

K20-AhOa-Si02-H20: Am. Jour. Sci., v. 257, p. 241-270. 

Meyer, Charles, and Hemley, J. J., 1959, Hydrothermal alteration in some granodiorites, in Swineford, Ada, ed., Clays 

and clay minerals-Proceedings of the 6th National Conference on Clays and Clay Minerals, Berkeley, California, 

Aug. 19-23, 1957: Internat. Ser. Mons. Earth Sci., no. 2, 

Pergamon Press, London. 

409. A PROPOSAL FOR CLARIFYING THE USE OF PLUTONIC CALC-ALKALIC ROCK NAMES 

By ANNA HIETANEN, Menlo Park, Calif. 

Because the common plutonic rock names such as 

granite, quartz monzonite, tonalite, and others are frequently used in the literature to represent slightly different compositional fields, each author should inform 

the reader in some simple effective way (for example, 

in graphic illustration) of the range of some of the 

major constituents in the rock types of his area. Because many common calc-alkalic rocks show systematic 

variation in their feldspar content and because some 

of the groups differ only in this respect, a ternary dia-
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293>-4.3,5 D-341 

grrun with albite, orthoclase, and anorthite at the three 

corners seems well suited for the purpose. For example, the feldspar content of the igneous rocks from 

the northwestern part of the Idaho batholith was successfully used as a basis for the subdivision of large 

petrologic groups into smaller units. Using the new 

petrochemical calculations based on molecular proportions by Niggli ( 1936) and further developed by Barth 

( 1952, 1959) and Eskola ( 1954), the feldspar content is 

expressed in terms of molecular nonns. It is customary 

to illustrate the no11native feldspar content in the OrAb-An diagram .. 

The n1olecular norms of the feldspars in 23 analyzed 

samples of rocks of the northwestern part of the Idaho 

batholith are shown as dots on figure 409.1. For a few 

analyzed rocks the weight norm is shown by a cross 

connected to the corresponding molecular norm with a 

short line. 'V' eight norms plot only slightly farther 

An 

Ab Or 

15 30 55 75 

Q M 

Granite 30-35 <5 

Quartz monzonite 20-30 5-10 

Monzotonalite 20-25 5- 10 

Tonalite 20-30 5-10 

Quartz diorite 10-20 10-20 

Gabbro 5-10 20-40 

Mafic gabbro <5 > 40 

FIGURE 409.1.-Ternary diagram showing the normative feldspar content of rocks from the Idaho batholith, and subdivision of some common calc-alkalic rocl<s. Ab, Or, and An 

refer to the molecular norms· of albite, Ol'thoclase, and anorthite. Dots refer to the molecular norms and crosses to the 

weight norms of rocks of the Idaho batholith. Ranges of Q 

and M from a ternary diagram for molecular norms of quartz 

(Q), feldspar (F), and femic constituents (l\f) of the same 

rocks are shown above. In most rocks Q decreases and M 

increases toward the An corner. Monzonite and calcimonzonite contain very little or no quartz. 

from the albite corner than the corresponding molecular 

norms. The ranges of quartz ( Q) and of femic constitutents (.l\1) in several subunits such as quartz monzonite, monzotonalite, and tonalite are about equal, 

but the feldspar content is different. This ternary diagrmn (fig. 409.1) can be used successfully, therefore, 

to illustrate the petrologic classification. The fact that 

the diagram does not show an overall systematic change 

in the quartz and femic constituents does not destroy its 

usefulness because the feldspar composition can be used 

independently of the quartz and fernie constituents to 

establish the subunits. For completeness the ranges of 

Q and M in individual rock types are tabulated below 

the diagram. The field occupied by the igneous rocks 

can be subdivided in such a manner that each subfield 

contains plots for only one petrologic rock type. This 

is done by connecting the points of suitable anorthite 

contents on the Ab-An line to the orthoclase corner (tielines) and drawing dividing lines parallel to the Ab-An 

line. The composition of plagioclase along each tieline that joins a point along the A b-An line to the orthoclase corner is constant. Thus, the range of the anorthite content of the plagioclase in rocks whose molecular norms plot between two tie-lines, such as trondhjemite, granite-trondhjemite, and granite stays within 

the same limits, but the amount of orthoclase increases 

from left to right. The dividing lines parallel to the 

Ab-An side give the range of normative orthoclase in 

various rock types. Because a part of the potassium 

enters into the biotite structure, the relative amount of 

modal orthoclase in the biotite-bearing rocks is smaller 

than the normative orthoclase shown on figure 409.1. 

The tie-line drawn through An35 divides the potassium-poor interlllediate rocks that have been called 

synonymously quartz diorite and tonalite into two 

groups. The name quartz diorite is reserved, in this 

subdivision, for the more mafic group that contains 

more calcic plagioclase (An35 _50 ) and normally hornblende and biotite. .The name tonalite is used for the 

more silicic group in which plagioclase is generally 

An25 _35 and in which biotite is the only dark constituent. 

The intermediate group between tonalite and quartz 

m~nzonite is called monzotonalite. In Idaho the 

monzotonalitic composition is common among the hypabyssal porphyritic dikes which cut the country rocks 

of the quartz monzonite batholith. Tonalite occurs as 

small intrusive bodies and as a metasomatic contact 

facies near many quartz diorite bodies. Granodiorite 

in this classification is reserved, as customary, for the 

potassium feldspar-bearing quartz diorite. 

The position of the tie-lines and dividing lines were 

chosen as best suited for the rocks of the Idaho batholith and can be easily modified if necessary for other 
·D-342 GEOLOGLCAL SURVEY RESEARCH 19 61 

reg1ons. It is also considered that some large groups 

without a clear break in the mineral content and 

texture should not be subdivided in spite of a spread of 

their feldspar content outside of a singular subfield on 

figure 409.1. Because the plotted positions of the 

weight norms are only slightly different from those of 

the molecular norms, the same diagram can be used 

succes~fully for the weight norms, or a similar diagram 

can be constructed for the mode. 

REFERENCES 

Barth, T. F. " '·· 1952, Theoretical petrology: New York, Wiley 

and Sons, 387 p. 

--1959, Principles of classification and norm calculations of 

metamorphic rocks: Jour. Geology, v. 67, p. 135-152. 

Eskola, Pentti, 1954, A proposal for the presentation of rock 

analyses in ionic percentage: Acad. Sci. Fennicae Annates, 

A. III, 38, 15 p. 

~iggli, Paul, 1936, Uber molecularnormen zur Ge>;teinsberechnung: Schweizer. Mineralog. Petrogr. Mitteilungen., v. 16, 

p. 295-317. 

410. ORIGIN OF MOTTLED STRUCTURE IN BEDDED CALCIUM SULFATE 

By C. F. WITHINGTON, Washington, D.C. 

Many deposits of bedded gypsum or anhydrite have 

a mottled structure that has received little attention 

from geologists. This structure has been observed in 

deposits ranging in age from Silurian to Pleistocene. 

The mottled structure may or may not accompany the 

more common laminated structure. An excellent example of typical laminated gypsum in the Fort Dodge 

formation (McGee, 1884) of Permian(?) age at Fort 

Dodge, Iowa is shown on figure 410.1. The deposit is 

as much as 8 feet thick and lies under a mantle of 

glacial drift. The gypsum is white to light gray, 

coarsely crystalline, in layers that range from about 

1 inch to as much as 3 feet in thickness. The layers 

are separated from each other by very thin clay seams. 

The gypsum consists of thin laminae, that can be seen 

best in the weathered rock as alternating parallel white 

FIGURE 410.1.-Laminated gypsum, Fort Dodge formation 

(Permian(?) age), Fort Dodge, Iowa. Sedimentary structure is a ripple mark. Distortion of laminae is due to 

penecontemporaneous deformation, compaction of sediments 

.and possibly to expansion of anhydrite on hydration to 

gypsum. 

and gray bands ranging from about 1 mm to as much 

as 10 mm in thickness, and averaging about 3 mm. The 

white laminae, which generally are the thicker, consist 

of nearly pure gypsum. In the darker laminae the 

gypsum is accompanied by small amounts of silt, organic matter, calcite, and limonite. Nodules of white 

gypsum as much as 4 mm in diameter are scattered 

through the rock; one may infer that these were formed 

at the time of sedimentation because the laminae are 

bent by compaction below the nodules, but not above. 

Laminated gypsum contrasts markedly with the 

mottled gypsum, an example of which, shown on figure 

410.2, is from Silurian rocks east of Port Clinton, Ottawa County, Ohio. Calcium sulfate is scattered 

through about 460 feet of the Tymochtee dolomite as 

beds and as nodules in dolomitic shale. The calcium 

sulfate is in the form of gypsum from the surface down 

to about 80 feet, where it gives way to anhydrite. The 

shale beds that contain the nodules are as much as 10 

FIGURE 410.2.-Mottled Silurian gypsum from Ottawa Oounty, 

Ohio. Calcium sulfate appears to have grown in dolomitic 

mud in bottom sediments. Small veins of secondary gypsum 

formed during hydration of anhydrite to gypsum. 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 2 9 3~4 3,5 D-343 

feet thick. In thin section, a nodule of gypsum cuts 

across undisturbed beds of silt. In places, the beds of 

silt bend around both the top and bottom of the nodules. The contact. between the gypsum and the silt is 

sharp, and little silt can be found within the individual 

nodules. The nodules are made up of very fine crystals 

of gypsum and have a feathery texture. Near the edges 

of some of the nodules, the crystals become coarser and 

may be pseudomorphic after crystals that probably 

were originally anhydrite. Several gypsum crystals 

replace each anhydrite crystal. 

Another example of mottled gypsum is east of Feldman, Pinal County, Ariz., about 9 miles south of 

Winkelman. These beds are among the youngest in 

which the mottling has been observed. The gypsum is 

in the Gila group (middle ( ~) Tertiary to Pleistocene) 

in at least 6 beds that range in thickness from less than 

2 feet to as much as 8 feet. The beds crop out for about 

a mile along the east side of the San Pedro River, and 

dip 5° to go E. The gypsum is aphanitic, white, and 

compact, and is mottled with thin silts'tone seams (fig. 

410.3). The gypsum beds are separated from each other 

by tan gypsiferous siltstone beds about 2 feet thick, 

which carry nodules of gypsum as much as 1 inch in 

diameter in a matrix of siltstone (fig. 410.4). 

Dark rims of compacted mud as much as 1 mm thick 

surround the gypsum nodules. Microscopically the 

gypsum is in finely crystalline masses that distort the 

bedding of the siltstone. No anhydrite or other salts 

were noted in samples from this deposit. 

The origin of laminated gypsum seems clear cut. 

U elden ( 1924) was the first to recognize that the laminae 

resulted from cyclical (probably annual) variations in 

the percentage of calcium sulrate in the basin of deposition. These changes, which affected the rate of crys-

.PIGURE 410.3.-Mottled gypsum from Pleistocene lake bee!, Pinal 

County, Ariz. White aphanitic gypsum is mottled with thin 

brown siltstone seams. Picture shows two surfaces cut at 

right angles: bedding surface (below black iine), and vertical 

surface (above black line). 

FIGURE 410.4.-Mottled gypsiferous siltstone from Pleistocene 

lake bed, Pinal County, Ariz. The gypsum has grown in a 

matrix: of silt. Dark rims around white gypsum nodules are 

compacted silt. 

tallization of calcium sulfate, were brought on 

periodically by increases in the amounts of calcium 

carbonate, clastic grains, and bituminous material carried into the basin by water of low salinity. 

The origin of mottled gypsum is less certain. R. T. 

Hazzard, as quoted by Imlay (1940, p. 36), was perhaps the first to offer an interpretation. He described 

the mottled gypsum or the "chicken wire lattice structure" in the Cretaceous Ferry Lake anhydrite in the 

subsurface of southwestern Arkansas and northeastern 

Texas, where masses of anhydrite are separated by thin 

films of calcareous mud. His conclusion "·as that discrete, nearly gelatinous anhydrite masses settled at the 

same time the mud was settling. Imlay (1940, p. 36) 

suggests, instead, that the mottled structures were 

formed by wave action in shallow muddy water before 

the solidification of the anhydrite. Dunham (1948) expressed the opinion that some. varieties of mottled anhydrite were formed by abrasion of the accumulating 

anhydrite masses, and that others were formed by replacement of the dolomite by anhydrite. 

None of these theories of origin seems to fit the relations observed in samples described here. \Vave action, 

which would cause abrasion of anhydrite particles, 

would result in such primary structures as graded 

bedding in the gypsum bed (Weller, 1960, p. 357), instead of the irregular arrangement in the typical 

mottled structure. In addition, no firm evidence for 

replacement of the host rock by calcium sulfate ·was 

observed. 

An alternative that is in accord with the available 

facts is that the calcium sulfate masses grew in place 
D-344 GEOLOGICAL SURVEY RESEARCH 1 9 6 1 

in the bottom sediments after the sediments were deposited, but before they were lithified. The nodules 

of calcium sulfate m~ty have crystallized in the bottom 

sediments . from concentrated interstitial solutions. 

Some of the nodules have displaced the host rock without notable distortion of the bedding, but others appear 

to have pushed the host rock aside. This distortion 

may have taken place at the time of growth of the 

nodules or at the time of compaction of the sediments, 

but clearly it was at a time when the beds were still plastic and not yet lithified. From this, one may suppose 

that abundant ·water carrying calcium and sulfate was 

available to supply the ·ingredients of the nodules. The 

large nodules probably formed by the accumulation of 

calcium sulfate on small "seed" crystals of gypsum or 

anhydrite that were already·present within the silt. 

Most of the megascopic calcium sulfate that has been 

identified from Recent sediments is in the form of 

individual crysta.ls or rosettes of selenite· (for instance, 

Eardley and Stringham, 1952; V er Planck, 1952, p. 

47-48). Masson (1956) also found thin layers of gypsmn and gypsiferous shale associated with the selenite 

crystals. Possibly some mottled gypsum originated as 

selenite masses, for Douglas and Goodman (1957, p. 

832) have determined that selenite crystals can be 

altered to granular gypsum by pr~ssures equivalent to 

1,000 to 6,000 feet below the surface. However, many 

of the deposits in which mottled gypsum has been 

found were never buried to such depths, and therefore 

cannot have been subjected to such pressures. 

Most of the calcium sulfate was probably deposited 

directly as rock gypsum or anhydrite. The form would 

depend in part on the temperatures of the unprecipitated brines contained in the sediments. In fresh water, 

for example, anhydrite will be precipitated at 40°0 

or above; gypsum is the stable mineral below 40°0. In 

more saline water, the limiting temperatures at which 

anhydrite can form are lowe~· (MacDonald, 1953, p. 

890). Although it appears that much of the gypsum is 

pseudomorphic after anhydrite, there is no way of telling whether anhydrite was the original form deposited, 

or whether the calcium sulfate was altered from gypsum to anhydrite after deposition, and then subsequently was altered again to gypsum. Temperatures 

above 40°0 have been reported in brines (Douglas and 

Goodman, 1957, p. 833) but bottom sediments are poor 

conductors of heat, a.nd even if the tmnperature in 

brine is above 40°0, the temperature in the sediment is 

not necessarily high enough for the precipitation of 

anhydrite. 

vVhen anhydrite is hydrated to gypsum by nearsurface waters, a theoretical expansion of between 30 

and 50 percent (Grabau, 1920, p. 359) takes place. In 

no gypsum deposit has evidence been found for a swelling of this magnitude. The rims of compressed shale 

surrounding nodules -of gypsum indicate that some of 

the expansion on hydration compacted the shale; additional increase in volume can be accounted for by the 

small veins of satinspar that have been deposited in the 

surrounding shales (Bundy, 1956, p. 252), presumably 

by the same waters that hydrated the anhydrite. The 

removal of the more soluble salts, which may have been 

deposited with the calcium sulfate by these smne solutions, would compensate, in part, for lack of volume 

increase on hydration of anhydrite. 

REFERENCES 

Bundy, ,V, M., 1956, Petrology of gypsum-anhydrite deposits in 

southwestern Indiana: Jour. Sed. Petrology, v. 26, no. 3, 

p. 240-252. 

Douglas, G. V., and Goodman, N. R., 1957, The deposition of 

gypsum and anhydrite: Econ. Geology, v. 52, p. 831-837. 

Dunham, K. C., 1948, A contribution to the petrology of the 

Permian evaporite deposits of northeastern England: Yorkshire Geol. Soc. Proc., v. 27, pt. 3, p. 217-227. 

Eardley, A. J., and Stringham, Bronson, 1952, Selenite crystals 

in the clays of Great Salt Lake [Utah] :Jour. Sed. Petrology, 

v.22,no.~p.234-238. 

Grabau, A. W., 1920, Geology of the non-metallic mineral deposits 

other than silicates, v. 1, Principles of salt deposition: New 

York, McGraw-Hill Book Co., Inc., 435 p. 

Imlay; R. W., 1940, Lower Cretaceous and Jurassic formations 

of southern Arkansas: Arkansas Geol. Survey Inf. Circ. 12, 

p. 35-36. 

MacDonald, G. J. F., 1953, Anhydrite-gypsum equilibrium relations: Am. Jour. Sci., v. 251, no. 12, p. 884-898. 

Masson, P. H., 1956, An occurrence of gypsum -in southwestern 

Texas: Jour. Sed. Petrology, -\r. 25, no. 1, p. 72-77. 

McGee, W. J., 1884, Descriptions of quarries and quarry regions, 

chap. 6, -in Report on building stones of the United States 

and statistics of the quarry industry: Rept. lOth Census, 

v. 10, p. 256-265. 

Udden, .J. A., 1924, Laminated anhydrite in Texas: Geol. ·soc. 

America Bull., v. 35, no. 2, p. 347-354. 

Ver Planck, W. E., Jr., 1952, Gypsum in California: California 

Di0'lines Bull. 163,151 p. 

"'eller, J. M., 1960, Stratigraphic principles and practice: New 

York, Harper Bros., 725 p. 
SHOR'l.' PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293'-4.3·5 D-345 

4ll. CHEMICAL BASIS OF MINOR-ELEMENT ASSOCIATIONS IN COAL AND OTHER CARBONACEOUS SEDIMENTS 

By P.I~T:tm Zuuovic, TAISIA STADNICHJ<;NKO, and NOLA B. SHEFFEY, "\Vashington, D.C. 

In a previous paper on the relative affinity of 15 minor elements Jor organic matter, Zubovic and others 

(1960) suggested t:ha,t those elements associated with 

organic matter in coal are held as metal-organic complexes. In this pnper the relative affinities of these elements are correlated with those properties that are most 

likely to affect the formation a.nd stability of such 

metaJ-orgnnic complexes. Thus, the geochemical behavior of the elements in the coal-for1ning environment 

.is further characterized. A n1ore rigorous recalculation 

of the or.iginnJ. dn.ta on 13 sink and float samples has 

produced minor changes in the order of affinity of 

these elements foe organic matter of coal. The order 

reported earlier was based on the frequency of the appearance of the elements in quartile ranges, whereas in 

this paper the order is based on more rigorous treatment of the data (fig. 411.1). 

The 15 elernents are relatively r~u·e, whereas the 

am.ount and variety of organic .matter w.ith which they 

form complexes are large. This relation, coupled with 

the .influence o:f certain chemicaJ properties of the metal 

ions, provides optimum conditions for the formation of 

stable metaJ-organic complexes. The chemical properties are: (a) size and charge of the ion, (b) bond 

TABJ-B 4:11.1.-lon·ic chm·ae, ionic radius, and bond configuration 

of the elements 

Vuloncy stnto Ionic rndlus In Most probnblo bond configurntion 

Angstroms (Moeller, 1952) (Pnuling, 1960) 

Ge+4 _______ .- _ _ _ _ 0. 53 

v+a- - - ----------- . 7 4 

V+• ________ -- _--- . 60 

Be+2______________ . :31 

Ti+4______________ . 68 

Gu.+s _ _ _ _ _ _ _ _ _ _ _ _ _ . 62 

B +a _ _ _ _ _ _ _ _ _ _ _ _ _ _ . 20 

N i +2 _ _ _ _ _ _ _ _ _ _ _ _ _ _ . 7 2 

Cr+2______________ . 84: 

Cr+s______________ . 69 

Co+2 __________ • _ _ . 7 4 

Y+a______________ . 93 

Mo ________________________ _ 

Cu+•------------- . 96 

Cu+2_____________ . 70 

S n +2 _ _ _ _ _ _ _ _ _ _ _ _ _ _ . 71 

Sn+•-------------- 1. 12 

Ln,+s______________ 1. 15 

ZnH______________ . 74 

604493 0-61-23 

octn.hedral. 

planar. 

planar. 

tctraheclrn.l, planar. 

tetnthcclra.l, oct~•heclral. 

tetrn.hcdral, octahcdml. 

tetrahcdml. 

phtmu-. 

planar. 

phtnar. 

pltwar. 

octahedral. 

tetrahedral. 

planar. 

? 

oct~•hecl ra.l. 

octahedral. 

tetrahedral. 

configuration and coordination number (table 411.1), 

(c) tendency towa.rd formation of covalent rather than 

ionic bonds, and (d) tendency to combine with nitrogen 

rather than with oxygen or sulfur of the donor molecule. Generally, smaller size and higher charge 

increase the tendency to forn1 more stable complexes. 

The stability of such complexes decreases as their bmid 

configuration changes from octahedral (coordination 

no. 6) to phmar (coordination no. 4) to tetrahedral 

(coordination no. 4). The relative strengths of such 

bonds (M:oeller, 1952, p. 204) are 3.0, 2.7, and 2.0, 

respectively. Complexes in which the metal is bonded 

to nitrogen as the donor atom are mostly covalent and 

most stable, whereas those bonded to oxygen are mostly 

ionic and less stable. Sulfur-to-metal bonds form the 

least stable metal-organic complexes. The ionic radii 

(Pauling, 1960, p. 514, 518) and the types of bond 

configurations (:~1oeller, 1952, p. 269) of these elements 

are given in table 411.1. 

Figure 411.2 shows that the relative stability of the 

hi valent metals, Fe, Co, Ni, Cu, and Zn, remains unchanged for different donor molecules. In this group, 

the charge-size relation holds for Fe, Co, Ni, and Cu. 

Zinc, however, forms only tetr:.thedral sp3 complexes 

which are less stable than the planar complexes formed 

by the other four metals using available "d" orbitals. 

Copper, which is the most stable in this series, does not 

show this stability in coal. 

In figure 411.1B, size of the metal ions is related to 

their affinity for organic matter of coal. Ionic radii 

are given for two valencies of V, Cr, Cu, and Sn. V+4, 

Cr+S, Cu+\ and Sn+2 better fit the curve shown than 

other valencies of these elements. Divergence from the 

curve for the first five elements listed (fig. 411.1B) and 

for zinc is the result of other factors. Figure 411.10 

shows the ionic potential (charge/radius) effect and 

again the fit is fairly good. Figure 411.1D relates bond 

strength, charge, and radius of the ions to their affinity 

for organic matter. 

It is apparent in figures 411.1A and 0 that the elements are arranged· in four general levels (dashed 

lines). In figure 411.1D the most stable configurations 

also fall into sim.ilar levels. In figures 411.10 and D. 

the levels for La and Zn are different. In all of the 

figures the valency states V+4 , Cr+3 , Cu+1, and S1i+2 better 

fit the curves than the valency states V3+, Cr2+, Cu2+, 

and Sn4+. 
.... 

ffi100r-----------------------------------------------~ 

s 

::::!: 

(.) 

z 

~ 0::: 

0 

I 

1-

3: 

0 

UJ 

!;i: 

u 

~ 25 (/) 

< 

1-

z 

UJ 

(.) 

a:: 

~ Ge 

10 

(/) 

::> 

c 

~5 w 

(.!' 

0::: 

< I 

(.) 

A 

o4+ 

--- 04+ 

0 

0 02+ 

02+ 

0 G . Ge Be a Tt Zn 

c 

0 

03+ 

Ge 

25 

~ 

I 20tG xo o 

~ --.------- 0::: (J) XC 

~ :2 15 XO ,64+ 00 A 

x0 4+ 

z~ ~ 6 o3+ 

0 (.) XC 3+ 

c:c_ xo X z 10 6 o-~--o... __ _ UJ Q XC XC 

0 

XCJ 

(.!' 

0::: 

< 

::I: 

(.) 5~ 6 6 

2+ 4+ 0 • 0 

x0 2+ 

62+ 

04+ 

xo 

----.62+ 

X6+ 

Zn 

I 

X-$ 

Ga Ti B V Ni Cr Co Y Mo Cu Sn La Zn 

DECREASING AFFINITY FOR THE ORGANIC MATIER OF COAL 

Bond configurations: 6 Tetrahedral 0 Planar o Octahedral 

x Preferential configuration D 

FIGURE 411.1.-Affinity of 15 minor elements for organic matter in coal in relation to their ionic charge, ionic radius, and bond strength . 

t:1 

~ ~ 

0 

t::<.:l 

0 

~ 

0 

0 

e,-t 

0 

> 

~ 

~ 

~ t::<.:l 

to<: 

l:tl 

t::<.:l 

[/2 

t::<.:l 

> 

~ 

0 

~ 

.... 

~ 

0) 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 2 9 3>-4,3,5 D-347 

Fe Co Ni Cu Zn 

FIGURE 411.2.-Stnbility constants· for the bivalent metals. A, 

trinminotrietbylamine; JJ, salicylaldehyde,· 0, ethylenediamine. 

In the environment in which coal is formed, there is 

a partitioning of elements between the organic and inorganic phases. Such elements as Be, Cr, Ga, and Sn 

fornl very insoluble hydroxides at pH higher than 4. 

Others, such as Cu, Zn, and Sn, form insoluble sulfides. 

fi 2S is generally available because of the activity of 

bacteria and because I-I2S is the stable phase of sulfur 

in this environment. The relation between the solubility of some of the inorganic compounds that can form 

and the stability of organic complexes of these elements 

helps to reduce further the· discr~pancies mentioned 

previously. TrivnJent chromium forms more stable 

complexes than trivalent vanadium. Quadrivalent 

vanadium, however, should form more stable complexes 

than trivalent chromium. In addition, trivalent cluomium can forn1 insoluble hydroxides, whereas most 

inorganic vanadium salts are quite soluble. Thus, to 

achieve the relation of vnnadium to chron1ium found in 

coal, vanadium should be quadrivalent, or some 

chromium should be precipitated as hydroxide. 

The general order of stability of the organic complexes of the biva.Ient metals is Be+2>Cu+2>Ni+2> 

Co+2>Zn+2>Fe+2 (Irving and Rossotti, 1956). This 

same order is found in coals for Be, Ni, Co, and Zn. 

The position of copper in this series does not agree with 

the coal data. However, if copper is in the univalent 

state, it forms less stable tetrahedral complexes, thus 

explaining its lower affinity for the organic matter· of 

coal. The stable copper minerals in bog-water .environments contain copper in this univalent state (Garrels, 

1960, fig. 6.25). Although copper sulfides containing 

bivalent copper are very insoluble, they are not stable 

phases in this environment. The sulfides of Ni, Co, and 

Zn have about the same equilibriwn constants, but their 

relative affinity for organic matter in coal reflects tpe 

relative stability of the organic con1plexes which they 

form. In addition, Ni and Co cannot be precipitated 

by H 2S from an acid solution. It is interesting that 

V+\ Cr+3, Co+2

, Ni+ 2, and Cu+1 can ~oexist in the 

same bog environment (Garrels, 1960, figs. 6.25, 6.29, 

6.30, 7.1, 7.5). 

The lack of affinity of tin fur organic matter in coal 

is assumed to be a result of its reduction to the bivalent 

ion, the large size and low charge of which causes the 

formation of unstable organic complexes. An alternative explanation is that the highly insoluble Sn ( Ofi) 4 

is formed before the element gets to the swamp, thus no 

tin is available for organic complex formation. The 

order of stability of the organiG oomplexes of the following trivalent metals is Ga > Y > La. This is also 

their order of affinity for organic matter in coal. Some 

of the elements, Be, B, and Ti, are not discussed in 

detail because their position is obvious. There are few 

data available on molybdenum. 

The preceding discussion of the relation of these elements in coal environments leads to generalizations as 

to the formation of smne sulfide minerals associated 

with organic matter. The principal factors involved 

are: (a) Eh-pli of the environinent, (b) availability of 

organic matter, and (c) availability of the metals. The 

first is important in producing an environment in which 

inorganic com pounds containing metals, such as copper, 

tin, and zinc are more stable than metal-organic complexes. The second and third factors are important in 

the partitioning of these elements in that if the availability of the metals is small and the avaihtbility of 

organic matter is large, n1ost of the elements would be 

disseminated in the organic matter as organic complexes, whereas few would forn1 finely dispersed inorganic precipitates. Perhaps only iron, which is one 

of the major elements, would precipitate in discernible 

quantities. In fact, most coals contain some pyrite. As 

the ratio of metallic elements to organic m~ttter increases, other less abundant elements that fonn weakly 

stable complexes tend to form numer~us minute miileralized pockets. Thus, zinc, lead, and copper are frequently found dissen1inated as sulfides in coal. vVhere 

the supply of the elements is large and that of organic 

matter small, one would expect n1ost of these elements 
D-348 GEOLOGICAL SURVEY RESEARCH 1 9 61 

to occur as inorganic compounds. Economic deposits 

of such metals as copper, zinc, iron, and perhaps the 

vanadium-ura.nium ores of the Colorado Plateau commonly :form in this way. Despite the fact that vanadimn has a high affinity for organic matter, it forms 

very labile complexes in which the exchange reactions 

are quite fast. The organic matter could thus act as a 

regulating trap in whiclt the element is held until a suitable reaction to forin an insoluble mineral comes into 

being. 

Figure 411.1A can be used as a general guide to the 

occurrence of elements in inorganic phases. if an element such as vanadium appears as an inorganic phase 

in •organic-rich sediments, then it can be assumed that 

the complex-forming ability of the organic matter is 

saturated. Unless they are extremely rare, elements 

with a lower affinity for organic matter should also 

form inorganic phases, provided suitable insoluble combinations of anions and cations come in juxtaposition. 

If zinc or copper minerals are absent, then minerals 

containing elements with a higher organic affinity 

should also be absent. IfNi and Co minerals appear, it 

must be assumed that the pH of the solutions at the 

time of tlu~ir formation was higher than usual. Other 

elements which form insoluble hydroxides or sulfides 

should also be precipitated. l\{ost of the processes are 

exceedingly complicated. 

REFERENCES 

Garrels, R. M., 1960, Mineral equilibria : New York, Harper 

and Bros., 245 p. 

Irving, Harry, and Rossotti, Hazel, 1956, Some relationships 

among stabilities of metal complexes : Acta Chemica Scandinavica, v. 10, no. 1, p. 72-93. 

Moeller, Therald, 1952, Inorganic chemistry: New York, John 

'Viley and Sons, Inc., 966 p. 

Pauling, Linus, 1960, The nature of the chemical bond, 3d ed.: 

Ithaca, New York, Cornell Univ. Press, 644 p. 

Zubovic, Peter, Stadnichenko, ·Taisia, and Sheffey, N. B., 1960, 

The association of some minor elements with organic and 

inorganic phases of coal, in Short papers in the geological 

sciences: U.S. Geol. Survey Prof. Paper 400-B, p. B84-B87. 

412. SOME MECHANISMS FOR COOLING HYDROTHERMAL FLUIDS 

By PAUL B. BARTON, Jr., and PRIESTLEY ToULl\UN 3d, vVashington, D.C. 

In recent years the temperatures of formation of 

several hypogene ore deposits have been studied in 

some detail by various workers, and it is expected that 

many more such studies will be made in the future as 

methods of geothermometry are perfected. Some of 

the studies have indicated that there are definite 

thermal gradients associated ·with the mineralization, 

just as had been commonly suspected for many years. 

A recent study of thermal gradients during mineralization in the Central City district, Colo. (P. IC Sims and 

P. B. Barton, Jr., unpublished data, 1961) has led us 

to examine the possible mechanisms by which temperature change may occur in. ore-forming fluids. Many 

discussions of ore-forming processes attribute cooling 

of the ore-bearing solutions to heat loss to cooler wallrocks. I-Iowever, in addition to heat exchange with 

wallrock, we believe that three other processes may 

make significant contributions to the thermal balance 

during ore formation. These processes are (a) heat 

exchanges in chemical reactions taking place in the 

solutions or wallrocks, (b) mixing of the solutions with 

ground water, and (c) adiabatic expansiol). of the fluid 

(including boiling), especia1ly irreversible expansion 

through a constriction, commonly referred to as 

throttling. 

Before the above-mentioned processes are discussed 

quantitatively, it should be pointed out that apparent 

temperature gradients can very well be due only to 

timing. If a mineral forms over a span of time during 

which the temperature in the vein changes, study of 

crystals formed at different times will yield different 

temperatures of formation. Thus, if only a few specimens are studied, the different temperatures determined 

may give the impression of an instantaneous spatial 

temperature gradient but may, in fact, represent only 

the change of temperature with time. Evidence that 

such temporal variations do occur in mineralization is 

furnished by zoned sphalerite crystals in which inclusion-filling temperatures (for example, Roedder, 

1960) indicate variation in temperature during crystal 

growth. J(utina (1957) and Smirnov (1960) consider 

that some types of zoning originate through the deposition of different mineral assemblages in different places 

from different solutions. 

Many of our colleagues, and especially P. IC Sims 

and E-an Zen· of the Geological Survey, were very 
SHORT PAPE-RS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293~-4,3,5 D-349 

helpful by their comments and critical discussions of 

field and theoretical aspects of the problems involved. 

HEAT CONDUCTION INTO W ALLROCK 

Qu:tntitu,tive evaluation of heat conduction into wallrock is extremely difficult (see discussion by Clark, 

1959) because the heat-flow calculations depend on such 

uncertain geologic factors as rate of flow of solution 

and its vn.riation with time, length of time during 

which the soluti.on flows, rn,te of change of the solution 

at its source, and the like. Calculations by Lafitte 

(1958) led him to the conclusion that heat loss by conduction to t:he walls is unimportant in most veins. Fiis 

Cltlculations also show that if the temperature of the 

incoming solution decreases suddenly, a reversed thermal gradient along the vein may persist for a considerable time. 

A serious objection to cooling by heat exchange with 

wall rock is illustrated by studies of thermal gradients 

during mineralization at Central City, Colo. (P. IC 

Sims and P. B. Barton, Jr., unpublished data, 1961). 

These studies suggest that the ore-forming solutions 

moved upward and outwa.rd from a central source at 

temperatures on the order of 600°C for considerable 

distn,nces ( n,t least several thousand· feet) with only a 

small temperature drop. Then, in a narrow region 

perhn.ps only 1 or 2 thousand feet wide, the temperatm:es dropped rapidly and very irregularly· to about 

300°C. Even in this narrow zone there is a great range 

of temperatures between adjacent veins and even 

within the same sphalerite crystals, as if each vein had 

its own cooling pa.tte111 that was independent of nearby 

veins. Farther out the temperatures drop to 150° to 

200°C. The localized steep thermal gradient and the 

extremely erratic distribution of temperatures within 

the region where temperatures were dropping rapidly 

n1ake it impossible to attribute the gradient to simple 

loss of hea.t. to cooler wall rocks. 

Thus, alt-hough heat loss by conduction to cooler wallrocks Clu1not be fully assessed on the basis of presently 

n.vailable dnJa, evidence from some districts raises ob-

:iections to this process as the mechanism for cooling 

solutions from magmatic to surface temperatures. 

Other geologically feasible processes are considered 

below. 

HEAT EFFECTS OF REACTIONS TAKING PLACE IN 

THE SOLUTIONS AND W ALLROCKS 

Endothermic reactions occurring within the solution 

or between the solution and the wallrocks could cool the 

solution. In fact, however, most of the predictable 

reactions are exothermic and therefore supply the 

geologic system with additional heat to be dissipated. 

~{ost minei·als decrease in solubility as temperature decreases, indicating that the precipitation reactions are 

exothermic and would tend to heat, rather than cool, 

the solution. Reactions in the fluid phase, such as the 

hydration, ionization, and disproportionation of so2 

proceed with falling temperature and likewise are 

exothermic. :Many of the reactions involved in wallrock 

alteration (sericitization and argillization of feldspa.r, 

chloritization of ferromagnesian minerals) n1ay be regarded as retrograde metamorphic proceSSP.S and so 

are exothermic for the total system. Although precise 

calculations are again impossible, the data of Remley 

(1959, p. 263-266) indicate that the effect may be signif-

. icant. The heat released by complete sericitization of 

the aJkali feldspar of a quartz n1onzonite. according to 

the reaction 3l(A1Sia0s + 21I+~l(Al:_~Sia01o ( OH) 2 + 

6Si02 + 21(+ should be sufficient to raise its tmnperature 

by about 20°C, and kaolinization might produce heat 

sufficient to raise the temperature as much as 30°C. If 

the other alteration processes have similar heat effects, 

the conversion of fresh quartz monzonite or granodiOl·ite to an aggregate of quartz, sericite, clay minerals, 

and chlorite might conceivably release a quantity of 

heat capable of raising the temperature of the rock by 

as much as 100°C. 

This heat would, of course, be released gradually and 

in relatively small amounts throughout the entire alteration process. It would, however, add to the heat to 

be consumed by the endothermic processes described 

below, and would be a significant factor in reducing the 

amount of heat that could be lost by the solution in 

heating the wa.llrocks. 

In certain cases, such as the alteration of clay-rich 

sediments or the development of tactites, endothermic 

reactions may become important 1nechanisms of heat 

consumption. 

MIXING WITH GROUND WATER 

There is little doubt that a hot, rising solution can be 

cooled .by mixing with ground water, but the problem 

lies in demonstrating that this action takes place where 

mineral deposits are forming. If fractures permitting 

circulation are open to the stu·face (as is likely if the 

hydrothermal solutions are escaping to the surface), 

and if the pressure at a given point becomes less than 

the hydrostatic pi·essure of a column of meteoric water, 

convection should operate because the cool meteoric 

water will be denser than the warmer hybrid solution 

that results from the mixing of meteoric and hypogene 

solutions. The· amount of cooling will of course be 

controlled by the proportion of meteoric water 

added and by the temperatures and heat cap~~cities of 

the solutions .. If additional hypogene solutions mix 

with already partially cooled hybrid solutions, actual 

reversals in thermal gradients might appear. Meteoric 
D-350 GEOLOGICAL SURVEY RESEARCH 1 9 6 1 

solutions generally have low concentrations of soluble 

salts,. whereas hypogene solutions usually ha.ve very 

appreciable concentrations; hence, by the simple operation of measuring the freezing points of fluid inclusions· (Roedder, 1960), which measures the rela.tive 

amounts of dissolved material in the water from a series 

of samples, it should be possible to demonstrate whether 

ground wa.ter mixing has or has not ta.ken place. 

Studies of the hydrogen or oxygen isotopic composition 

of the fluid inclusions can also provide evidence of the 

role of ground-water mixing. 

ADIABATIC EXPANSION 

"Adiabatic expansion" means expansion of the fluid 

without heat exchange with its surroundings. We sha.ll 

discuss three va-riations of this process: reversible expansion, irreversible expansion or throttling, and 

boiling. 

A fluid rising slowly through an open fracture, and 

exchanging a negligible amount of heat with the walls, 

expands reversibly and adia-batically under the decreasing pressure of the overlying fluid column. Since a 

reversible adiabatic process takes place at constant entropy, the cooling of the fluid can be evaluated graphically by plotting isotherms on an entropy-pressure 

dia.grain (fig. 412.1). 

This process is relatively unimportant (or at least 

masked by other processes) in most minera-lized areas, 

for in order to attain the large pressure change required 

for appreciable cooling the solutions would have to rise 

through an unrealistica-lly large vertical distance. 

Ill 

a:: 

c( 

ID 100 1&.1. 

a:: 

::::l 

1/) 

~ 

g: 

20 25 30 35 40 45 50 

Irreversible expansion of the type known as throttling 

or as Joule-Thomson expansion takes place when a fluid 

from a reservoir at constant high pressure expands 

through a constriction into a second reservoir at lower 

pressure, as undoubtedly happens in the history of some 

hydrothermal fluids. Such an expansion takes place 

at constant enthalpy (Zemansky, 1943, p. 190-192), and 

thus the temperature change on expansion can be estimated graphically from isotherms plotted on an enthalpy-pressure diagram such as the one constructed by 

BanwelL(White, 1957, fig.1). A similar diagram calculated from data recently compiled by Pistorius and 

Sharp is·given in figure 412.2. It_ is evident that appreciable cooling can result at temperatures above 350° C to 

400° C by throttling: for example, a drop in pressure 

from 1,500 to 250 bars wi1l cause the solution to cool 

from 600° C to 430° C. At temperatures below about 

400° C the isotherms are so steep that little effective 

cooling can result; in fact, as is shown in figure 412.2, 

under some conditions (on the low-temperature, highpressure side of the Joule-Thomson inversion curve) a 

small amount of heating, rather than cooling, results 

from throttling. 

If the pressure on a liquid is reduced below its vapor 

pressure, boiling '"ill result with consequent cooling of 

the solution. The temperature drop in reversible boiling, which occurs in many hot springs, can be evaluated 

from figure 412.1, and the case where water flashes to 

steam can be evaluated from figure 412.2. Most studies 

of fluid inclusions indicate that the depositing solution 

was a single fluid phase (Smith, 1953), and thus this 

1000 

1/) 

a:: 

c( 

ID 100 

l&i 

a:: 

::::l 

1/) 

1/) 

1&.1 

a:: 

D.. 

-6 -4 -2 0 2 4 6 

ENTROPY, cal deg· 1mor 1 ENTHALPY, kcal morl 

FIGURE 412.1.-Entropy-pressure diagram for the system H 20. FIGURE 412.2.-Enthalpy-pressure diagram for the system H20. 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 2 9 3o--4.3·.5 D-351 

mechanism for heat dissipation may not be active in 

most deposits. 

Some of the processes suggested above may seem to 

be somewhat improbable at first glance, but closer inspection of a typical ore-forming system as described 

below suggests that such processes as throttling are 

almost inevitable. Burbank (1950), on the basis of entirely different evidence from the Red .Mountain area, 

Colo., concluded that throttling might be an important 

process; and, although he did not develop the quantitative aspects of the cooling, he did propose that steep 

temperature as well as steep pressure gradients might 

have existed. 

A .schematic model illustrating the behavior of an 

increment of solution under the influence first of adiabatic expansion and then of mixing with ground water, 

in agreement with the general pattern interpreted for 

the Central City district (P. IC Sims and P. B. Barton, 

,Jr., unpublished data, 1961), is shown in figure 412.3. 

In the actual· case, heat exchitnge with wallrock would 

smooth some of the sharp corners shown in figure 412.3, 

but it has .been neglected here in order to ·emphasize 

the other processes. The six curves shown in figure 

412.3 are different representations of the same increment of solution, in terms of different pairs of the vari-. 

abies time, temperature, pressure, and depth. 

0-

1-

~· 

:i 

~- 2-

LaJ 

Q 

"'O-r3·4 5 ~ 500 . 

..; 

0:: 

~ 1000 ~ 

0:: .1 a.. 1500- 2 

(J ~00·1 ___ .

:r 600 . 

~ 500. 

~ 400. 

~ 300. 

~ 200 

100 

TIME 

0 

1 

"' 

~ 

:i 

~2 LaJ 

Q 

0 500 1000 1500 2000 PRESSURE, BARS 

0 

"' ~ 500 . m 

~-1000 

::J "' . 

~1500 a.. 

0 

1. 

"' ~ 

:i2 

r.· 

!i: 

LaJ 

Q 

3 

5\Boiling curve for H20 . 3' 3 . 4 . 

2 1 

5 ...,!;Q_ (density H20 gjcm3) 

0.004 (solubility of silica, wt percent) 

0.48 

1 o:63 

100 200 300 400 500 600 700 

TEMPERATURE, •c 

'F10u1u~ 412.3.-Schematic behavior of an increment of solution: 

en route from source to surface. 

In figure 412.3, ( 1) represents the source of the flui.ds, 

probably the final crystallization stages of a magma. A 

temperature of 630° C and a pressure of 1,500 bars have 

been chosen arbitrarily. If the hydrothermal fluid constitutes a separate phase within the magma-as it must 

if separation is to occur-the pressure will be approximately lithostatic or greater. As the solution moves 

up an open fracture from (1) to (2) the pressure decreases only slightly' the decrease being equal to the 

hydrostatic pressure of a column of similar solution of 

height equal to the distance :from ( 1) to ( 2) . The 

small temperature decrease is estimated from figure 

412.1. Eventually the solution will reach a constriction (2) to (3). Some sort of constriction at some 

position is necessary or the whole vein would become a 

steam vent, open to the surface. The solution expands 

rapidly as it proceeds through the constriction, emerging at (3) at a much lower temperature and pressure 

than at ( 2) ; the amount of cooling can be predicted 

from figure 412.2. The actual position of the constriction that causes the throttling, and the possible existence of multiple constrictions, are not critical to the 

discussion here-some throttling must take place somewhere on the conduit if the solutions are to move from 

the source ( 1) to the surface ( 5) and, unless the sol utions are previously cooled to below about 400<? C by 

other means, significant amounts of cooling will take 

place \v hen the throttling occurs. 

Because of the decrease in density and the drop in 

temperature of the solution during the throttling it is 

likely that precipitation of the various vein minerals 

will be concentrated in this region, as suggested ~y Bur, 

bank (1950). Following the throttling the solutions 

may move farther at very slowly diminishing pressure 

from (3). to (3'); the temperature in this interval 

changes as shown in figure 412.1. However, the throt, 

t.led solution in the (3) to (3') region would have a 

very low density-0.11 gm/ cc in the model given in 

figure 412.3 ( l(ennedy, 1950b) -and would be in a mechanical1y unstable position relative to the cooler and 

denser solutions in the .. ground-water-mixing region 

above; hence there would be an opportunity for conv.ection to eliminate the ( 3) to ( 3') interval so that 

throttling should take place directly into the region of 

ground-water mixing. 

A possible consequence of the throttling is that precipitation takes place so rapidly· that metastable mineral assemblages are formed. This could lead to some 

serious difficulties in attempts to use various mineral 

assemblages as geothermometers. In the· study of the 

Central City district the sulfides from the region of 

presumed throttling occur- as well-defined crystals, and 
D-352 GEOLOGICAL SURVEY RESEARCH 1 9 61 

many sphalerite crystals show delicate growth hands 

of varying iron content that are difficult to imagine as 

having originated from highly supersaturated solutions. Moreover, hydrothermally leached surfaces inclicate that the overall process of deposition was at 

times reversed. Pending evidence to the contrary, we 

conclude that reaction rates were such that the growing 

surfaces of sphalerite (and presumably the other sulfides) were approximately equilibrated with the solution. Abundant data on the soh1bilities of vein minerals are available only for quartz, and a few of these 

data are noted at important points on the depthtemperature diagram in figure 412.3 ( l{ennedy, 1950a; 

Morey and Hesselgesser, 1951; and Fournier, 1960). 

The effects of composition of the solution on the solubilities of the various minerals can be very large and 

thus quantitative discussion is impossible at present. 

In the -region from (3') to ( 4) the magmatic solutions enter the region of circulating (cooler) ground 

waters and undergo rapid cooling at nearly constant 

pressure. From ( 4) to ( 5) the hybrid solutions move 

on toward the surface at steadily decreasing pressure 

with additional increments of ground water providing 

breaks in the cooling curve. If the path to the surface 

intersects the boiling curve for the solution (which 

would require a slight shift in the plotted curve for the 

solution on the temperature-pressure diagram in figure 

412.3), cooling by adiabatic boiling is possible. 

Because the calculations had to be based on the data 

for pure ·water even though hydrothermal fluids may 

contain large quantities of dissolved substances, figures 

412.1 and 412.2 are to be regarded as giving only a 

semiquantitative measure of the temperature changes 

taking place during adiabatic expansion. Other 

factors, however, such as heat exchange with the wallrock, and uncertainties in the temperatures and pressures, most probably introduce even larger errors so 

that the use of the data for pure water is a sufficiently 

good approximation. 

Several additional features of the model described 

above may be mentioned briefly: (a) As the magmatic 

source of the solutions -weakens toward the end of the 

mineralization the locus of ground-water mixing may 

move inward, and high-temperature mineral assemblages may thus be "quenched" and preserved. to record 

the former high-temperature conditions. (b) The pressures of deposition may differ very greatly from either 

the hydrostatic or lithostatic load, adding to the difficulty of evaluating pressure corrections for geothermometers (such as those commonly applied for fluid 

inclusion studies or the 25° C per kilobar correction for 

the sphalerite geothermometer) . A further consequence 

is that pressure of formation may not be a reliable measure of depth of formation, and this fact may have important implications in mineral exploration. (c) The 

large pressure differentials present during throttling 

would be especially favorable for the development of the 

breccia zones with which ore is so frequently associated. 

(d) Perhaps the various classes of hypogene mineral 

deposits are distinguished as much by the manner in 

"·hich cooling and pressure drop take place as by the 

actual temperatures and pressures of mineralization. 

Although we have discussed the cooling processes separately, several must have operated concurrently or successively in most ore deposits. The purpose of this 

paper is to call to the attention of geologists the possibility of these diverse processes so that field and laboratory studies may be designed to include an evaluation 

of their importance. 

REFERENCES 

Burbank, W. S., 1950, Problems of wall rock alteration in shallow 

volcanic environments: Colorado School Mines Quart. v. 45, 

no. lB, p. 287-319. 

Clark, S. P., Jr., 1959, Thermal calculations pertaining to ore 

deposition: Carnegie Inst. 'Vashington Year Book 58, 

p. 157-160. 

Fournier, R. 0., 1960, Solubility of quartz in water in the temperature interval from 25° to 300° C. [abs.] : Geol. Soc. 

America Bull., v. 71, p. 1867-1868. 

Remley, J. J., 1959, Some mineralogical equilibria in the system 

K20-Al 20 3-Si0 2-H20: Am. Jour. Sci., v. 257, p. 241-270. 

Kennedy, G. C., 1950a, A portion of the system silica-water: 

Econ, Geology, v. 45, p. 629-653, 

-- 1950b, Pressure-volume-temper.ature relations in water 

at elevated temperatures and pressures: Am. Jour. Sci., 

v. 248, p. 540--564. 

Kutina, Jan, 1957, A contribution to the classification ~f zQning 

in ore veins: . Universitas Carolina, Geologica, v. 3, 

p. 197-225. 

Lafitte, Pierre, 1958, Regime thermique au voisinage d'un filon 

hydrothermal: Acad. Sci. Paris Gomptes rendus, v. 246, 

p. 2148--2151. 

Morey, G. W., and Hesselgesser, J. M., 1951, The solubility of 

some minerals in superheated steam at high pressures: · 

Econ. Geology·, v. 46, p. 821-835. 

Pistorius," C. W. F. T:, and Sharp, W. E., 1960, Properties of 

water. VI. Entropy and Gibbs free energy of water in the 

range 10--1000° C: and 1-250,000 bars: Am. Jour. Sci., v. 258, 

p. 757-768. 

Roedder, Edwin, 1960, Primary fluid inclusions in sphalerite 

crystals from the OH vein, Creede, Colorado [abs.] : Geol. 

Soc. America Bull., v. 71, p. 1968. 

Smirnov, V.I., 1960, Types of hypogene zonality of hydrothermal 

ore bodies: Internat. Geol. Cong., 21st, Copenhagen, 1960, 

Rept., pt. 16, p. 181-191. 

Smith, F. G., 1953, Historical development of inclusion thermometry: Univ. Toronto Press, 149 p. 

·white, D. E., 1957, Thermal waters of volcanic origin: Geol. 

Soc. America Bull., v. 68, p. 1637-1638. 

Zemansky, M. W., 1943, Heat and thermodynamics: New York, 

McGraw-Hill, 2d. ed., 390 p. 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293o-4.3·5 D-353 

413. SOME PHYSICAL PROPERTIES OF BIKITAITE AND ITS DEHYDRATION AND DECOMPOSITION PRODUCTS 

By W. C. PI-liNNEY and D. B. STEWART, Minneapolis, Minn., and Washington, D.C. 

Bikitaite, LiA1Si20 6 .II20, was described by Hurlbut 

(1957, 1958) from its only knmvn locality at Bikita, 

Southern Rhodesia. As part of an investigation of the 

phase relations, stability, and geologic occurrence of the 

lithium aluminum silica,tes, some physical properties 

have been determined for bikitaite from. the type 

locality. The material was supplied from specimen 

R10364, U.S. National Museum, by Dr. George Switzer. 

The specimen hns not been analyzed chemically but its 

optical properties are identical to those reported by 

Hurlbut and the H 20 content has been found to be 8.8 

weight percent, in exact agreement with the theoretical 

H20 content. 

The authors ncknowledge the helpful assistance of 

B. J. Skinner in determining the refined cell dimensions and obtaining several high temperature X-ray 

powder-diffraction patterns of bikitaite, and for making 

two long heating experiments at atmospheric pressure. 

D. E. Appleman determined the bikitaite structure and 

provided a summary of its special features. Our colleagues Dorothy Carroll and Harry Starkey mensured 

the ionic exchange of hikitaite in their laboratories. 

Wayne Mountjoy analyzed the acetic acid leachate from 

bikitaite. 

X-RAY CRYSTALLOGRAPHY 

The unit-cell parnmeters of bikitaite were calculated from the d spacings of the (102), (111), (211), 

and (301) reflections measured relative to silicon 

(a=5.43071 A) as an internal standard with a diffractometer. Cmnputations were made on a digital computer, using an iterative method. The refined bikitaite 

parameters at 26° C are a=8.611 A, b=4.960 A, o= 

7.610 A, ,8=114°26', all measured with a precision of 

0.04 percent. These dimensions were used to calculate 

the d spacings given in table 413.1. Bikitaite d spacings 

reported by Hurlbut (1957, p. 796) are also shown in 

. table 413.1, however, the stilbite lines present in 

I-Iurlbut's dn,ta have been omitted. 

Precise cell dimensions determined by D. E. Appleman on a qmtrtz-calibrated precession camera using 

Mo Ka radiation are a=8.616 A+0.01 A, b=4.955 A+ 

0.005 A, o=7.611 A+0.01 A, ,8=114°26'+05', space 

group P21, cell content= 1 [LiAlSi206 · H20]. Appleman also determined tha.t bikita.ite is weakly piezoelectric. 

When bikitaite is dehydrated in air. at temperatures 

below 500°C on a heated diffractometer stage, no obvious cha.nge of symmetry occurs, although the intensities of several powder-diffraction lines change notably, 

and several high-angle lines shift slightly. The (100), 

(001), (101), and (112) lines becom.e more intense, the 

(112) especially so, and (301) becomes less intense as 

the H20 content decreases. . On rehydration, the line 

intensities return to their usual values. Similar behavior in synthetic zeolite A has been reported by Breck 

and others ( 1956, pp. fi969-5970). In the diffraction 

pattern of completely dehydrated "bikitaite" at room 

temperature, the (021), (121), lines are more intense 

and the (201), { (120), (312) }, and (113) lines are less 

intense than in fully hydrated bikitaite. 

CRYSTAL STRUCTURE OF BIKITAITE 

The crystal structure of bikitaite (Appleman, 1960) 

is a three-dimensional network formed by laterally 

linked zigzag chains of silicate tetrahedra extending 

parallel to [010]. There are three crystallographically 

nonequivalent kinds of silicate chains. The structure 

contains one large channel and several smaller channels 

parallel to [010] in which lithium ions and H 20 molecules are located. The distribution of Al and Si in the 

strl.wture and the structural reasons :for the dehydration behavior observed are being investigated. Studies 

to date have revealed no structural similarities to other 

lithium aluminum silicates or to analcime (N aAlSi20 6 · 

H20), wairakite ( CaAl2Si4012 · 2H20), or pollucite 

( CsAlSi206 · nH20). 

DEHYDR-ATION OF BIKITAITE 

The dehydration characteristics of bikitaite heated in 

air were accurately measured. Carefully purified -100 

mesh samples pf bikitaite were brought to constant 

weight at 120°. C in glass micro-weighing bottles. The 

bottles were then placed in regulated furnaces, and 

the stoppers were removed from the bottles for from 

one to six days. The stopper was replaced immediately 

before removing. each bottle from the furnace to prevent rehydration of the sample. The cooled bottles 

were weighed to determine the amount of I-120 lost. 

Each weighing was corrected for the difference in 

density of air at room temperature and air at the temperature of the experiment. All experiments were 

made in an individually air-conditioned laboratory in 

an air-conditioned building. The temperature and humidity varied little, so that the H 20 vapor pressure was 
D-354 GEOLOGICAL SURVEY RESEARCH 19 61 

nearly constant at 10.3 mm of Hg, as measured twice 

daily by the sling psychrometer. 

The temperature-composition isobar for the system 

LiA1Si20 6-H20 at 10.3 mm H20 pressure is shown on 

figure 413.1. The hikitaite dehydration curve is based 

on 28 experimental points at intervals of approximately 

10° C. The first loss of H 20 occurs at 160° C, and the 

TABLE 413.1.-Indexed X-ray powder.;.dijfraction pattern of 

bikitaite from Bikita, Southern Rhodesia (USNM R10364) 

[Intensity (I) visually estimated from powder film. · All permissible hkl in space 

group P21 calculated for unit-cell with a=8.611 A, b=4.960 A, c=7.610 A, jj=ll4°26'] 

I hkl duzA duz A measured dhkl A reported 

calculated Film No. 13473 Hurlbut (1957} 

8 100 7. 840 7. 865 7. 84 

5 001 6. 928 6. 930 6. 95 

3 I01 6. 762 6. 732 6. 84 

4 101 4. 371 4. 374 4. 39 

1 201 4. 247 4. 265 ------------

9 110 4. 192 4. 195 4. 19 

2 011 4. 033 4. 022 4. 03 

1 I11 3. 999 3. 991 ------------ 1 200 3. 920 3. 926 3. 91 

3 I02 3. 803 3. 806 3. 82 

10 002 3. 464 3. 462 3. 48 

10 202 3. 381 3. 371 3. 40 

4 111 3. 279 3. 284 3. 29 

4 211 3. 226 3. 215 3. 22 

4 210 3. 075 3. 076 3. 08 

1 112 3. 018 3. 023 ------------ 1 201 2. 931 2. 930 2. 93 

2 "3"01 2. 868 2. 870 2. 87 

012 2. 840 ------------ ------------ 1 212 2. 794 2. 794 2. 79 

1 102 2. 773 2. 739 ------------ "3"02 2. 688 ------------ ------------ 1 300 2. 613 2. 629 ------------ 2 211 2. 524 2. 523 2. 53 

I03 2. 515 ------------ 2. 52 

203 2. 491 ------------ ------------ "3"11 2. 483 ------------ ------------ 9 020 2. 480 2. 479 2. 475 

1 112 2. 420 2. 423 ------------ 2 {120 2. 365 } 2. 364 "3"12 2. 363 ------------

1 021 2. 335 2. 337 ------------ 1 T21 2. 328 2. 323 2. 320 

1 310 2. 312 2. 316 ------------ 003 2. 309 ------------ ------------ "3"03 2. 254 ------------ ------------

1 I13 2. 243 2. 240 ------------ 213 2. 226 ------------ ------------ 202 2. 186 ___ .... ________ ------------ 1 301 2. 167 2. 167 ------------ 121 2. 157 ------------ ---------a•--

TABLE 413.1.-Indexed X-ray powder-diffraction pattern ofbikitaite 

from B£kita, Southern Rhodesia (USNM R10364)-Continued 

I hkl duzA duz A measured dhk1 A reported calculated Fllm No. 13473 Hurlbut (1957) 

----

1 221 2. 142 2. 141 ------------ 401 2. 131 ------------ ------------ 402 2. 123 ------------ ------------ 1 220 2. 096 2. 097 ------------ 1 013 2. 094 2. 094 ------------

2 I22 2. 077 2. 077 ------------ 313 2. 052 ------------ 2. 045 

1 022 2. 017 2. 012 ------------ 1 103 2. 002 2. 005 ------------ 1 {212 2. 000 } 1. 996 222 2. 000 ------------

1 311 1. 986 1. 988 ------------

1 {400 1. 960 } 1. 959 1. 96 411 1. 958 

412 1. 952 ------------ ------------ 1 403 1. 942 1. 947 ------------

3 204 1. 902 1. 900 1. 900 

221 1. 893 ---------- 1. 895 

1 321 1. 876 1. 877 ---------- I04 1. 861 ------------ ------------ 2 113 1. 857 1. 855 1. 855 

[plus a number of additional lines] 

last of the H 20 is lost at 360° C. In contrast, differential thermal analysis of bikitaite (Hurlbut, 1957, p. 795) 

indicated that the H 20 loss began at 190° C and ended 

at 475° C. 

The dehydration curve of bikitaite shows curved segments between distinct breaks at 180° c and 2 weight 

percent H 20 lost, and 280° C and 6.6 weight percent 

H 20 lost. The theoretical and observed H20 content 

of bikitaite is 8.8 weight percent, so that these breaks 

correspond to one-fourth and three-fourths, respectively, of the H 20 molecules lost. The bikitaite unit 

cell oontains only a single H20 molecule, so the stepwise dehydration indicates that three energy barriers 

must be overcome during dehydration. It was hoped 

these barriers might be recognized by a precise crystal 

structure determination. Preliminary results of the 

crystal structure determination do indicate a specific 

structural site for about half of the H20 molecules, 

but the temperature interval during which this site 

is dehydrated is unknown. The remainder of the I-I20 

in the structure has not yet been located. 

The H20 lost in the dehydration interval from 160° C 

to 240° C is completely regained from the air at lower 

temperature, although rehydration is a slower process 

than dehydration. The reversible nature of the effect 

permits the H 20 content at a given temperature to be 

approached from both higher and lower temperatures, 
SHORT PAPE-RS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-4.3~5 D-355 

t 

(.) 

fBlkltaite 

25 

Oehydrated"bikitaite"and gas 

MOL PERCENT 

LiAISi206 I H20 

BIKITAITE 

Blkitaite and gas 

Gas 

Frouu.m 418.1.-'rhe temperature-composition isobar for the system LiAlSL!Oo-I-I~O at 10.8 mm H20 pressure. 

so that weighing demonstrates the results to he equilibrium values in this temperature range. However,. 

after being heated to between 240° C and 360° C and 

then cooled, many grains rehydrate completely, but the 

remainder rehydrate only partially as determined by 

measurement of refractive indices. The ratio of completely rehydrated to partially rehydrated grains apparently depends upon the highest temperature reached, 

the time at that tempernture, and the grain size. After 

being heated to between 360° C and 600° C and then 

cooled, some grains do not rehydrate, while some rehydrate either partially or completely. 

Ruiz-Menacho and Roy (1959) reported that bikitaite 

decomposed to ,8-spodumene at 400° C. No ,8-spodumene formed in air below 600° C in this study. 

The refractive indices of bikitaite decrease with the 

loss of H20, and increase during rehydration. The 

mine1;al remains binxial negative and the birefringence 

is nearly the same throughout. Optical study indicates 

that rehydration follows a series of discontinuous steps. 

Rims with higher indices are visible on some grains or a 

mixture of two or three types of homogeneous grains is 

fom1d. "Bikitaite" known to be completely dehydrated 

from weight-loss measurements is biaxial negative 

a=l.452, ,8=1.461, y=l.463.· Two commonly found 

types of homogeneous, partially rehydrated bikitaite 

have y= 1.473 and y= 1.486. These substances contain 

approximately 1.5 and 3.4 weight percent H 20, respectively, according to calculations .based on the rule of 

Gladstone and Dale as applied .to minerals by Larsen 

and Berman ( 1934, p. 30-32) . 

Bikitaite heated rapidly in air.to temperatures above 

750° C may decompose to ,8-spodumene as reported by 

Hurlbut ( 1957, p. 795), or -to other phases. Several experiments yielded ,8-eucryptite solid solution as well as 

,8-spodumene solid solution. One experiment at 800° C 

for 20 hours _yielded 98 percent of an unidentified substance that must be close to LiAlSi20 6 in composition 

and 2 percent of partially rehydrated bikitaite. The 

unidentified substance is biaxial positive, a= 1.520, ,B= 

1.523, y=l.534, 2V=medium, and has a distinctive 

X-ray powder-diffraction pattern with strong lines at 

d 4.04 (10), 3.48 (5), 3.21 (4), 2.50 (3); and several 

weaker lines. 

IONIC EXCHANGE PROPERTIES OF BIKITAITE 

The exchange of ammonium ions for lithium ions 

in bikitaite at 25 ° C was studied by standard procedures with 1 N ammonium acetate solution by Dorothy 

Carroll. She found that the ammonium ion exchanged 

was 0.3 milliequivalents per 100 gram.s of bikitaite, or 

0.061 percent of the lithium ions if only lithium ions 

were replaced. This amount is so small as to be 

negligible. 

The exchange of hydrogen ions from 1 N acetic acid 

for lithium ions in bikitaite was studied by Harry 

Starkey. The experiments were made in metal containers at 122°C and slightly over 2 atmospheres pressure. The leachate was analyzed by Wayne Mountjoy 

for lithia and silica to determine if the lithium was 

actually replaced or released through dissolution of the 

sample. The analysis showed 10 mg Si02 and 2.1 mg 

Li20 in the leachate from a 0.25 g sample. The silica 

a·nalysis indicates that 6.8 percent of the sample dissolved. Lithium in solution, in excess of that required 

to balance dissolved silica in the bikitaite ratio, amounts 

to 5.0 percent of the lithium theoretically present in the 

undissolv~d sample remaining, assuming that the Li: Si 

atomic ratio in bikitaite is exactly 1 : 2, and that no 

lithium-poor aluminosilicate formed during the experiment. Therefore, hydrogen ions apparently replaced 

5 percent of the lithium ions, an amount over 80 times 

the replacement of lithium ions by ammonium ions. A 

less accurate analysis of the leachate for alumina suggests that 9.6 percent of the sample dissolved, and that 

only 2 percent of the lithium ions were replaced by 

hydrogen ions. 
D-356 GEOLOGICAL SURVEY RESEARCH 1 9 61 

These two experiments suggest that limited ionic exchange of small ( ~o.5 A radius) hydrogen ions may 

occur in bikitaite, but that large (~1.5 A radius) ammonium ions are excluded. A-pparently even the largest channel in the bikitaite structure will not 

accommodate the ammonium ion. Magnesium ion is 

almost the same size as lithium ion, and is the most 

abundant of the ions substituting for lithium in Hurlbut's (1957, p. 794-795) bikitaite analysis. Therefore, 

ionic exchange of magnesium for lithium may occur in 

nature. 

HYDROTHERMAL DECOMPQSITION OF BIKITAITE 

All attempts to synthesize bikitaite failed, and only 

the decomposition of natural bikitaite under hydrothermal conditions was determined. On figure 413.2 

the results of holding natural bikitaite and 0 to 30 

weight percent H20 in sealed metal capsules under 

hydrothermal conditions for from 5 to 9 days are 

shown. Bikitaite reacted at 390° C in the range 1 to 

4 kilobars H 20 pressure to form eucryptite and petalite by the reaction. 

bikitaite eucryptlte petalite 

Short experiments showed that petalite 'and eucryptite 

precipitated as bikitaite dissolved. Ruiz-Menacho and 

Roy (1959) . reported the breakdown of bikitaite to 

eucryptite and ,8-spodumene at 1013 bars and 420° C, 

but observed no petalite. Petalite and. bikitaite are 

difficult to distinguish optically, and sm'all amounts 

of one mixed with the other might be overlooked. 

In some hydrothermal experiments of short duration 

members of the ,8-spodumene and ,8-eucryptite solid 

solution series formed metastably from bikitaite. 

Larger quantities of ,8-spodumene and ,8-eucryptite 

formed when bikitaite was decomposed without added 

H20 in the capsules. However longer experiments 

yielded increased amounts of petalite and eucryptite, 

so that the direction of the reaction is clear. In several 

experiments conducted between 400° and 450° C at 1;2 

to 2 kilobars bikitaite decomposed to a very fine grained 

mixture of silica-rich ,8-eucryptite solid solution 

(Li: Si=1: 1.94) and a phase somewhat more siliceous 

than LiAlSi206 • The mean index of the aggregate is 

t.518 and individual grains of well-crystallized 

,8-eucryptite have cu= 1.520 and £= 1.516. The new 

phase was not recognized optically in a mixture consisting almost wholly of large amounts of the new 

phase and ,8-eucryptite as judged from X-ray powderdiffraction patterns. The optical properties. must 

therefore be very similar to those of silica-rich 

,8-eucryptite solid solution. The strongest lines of the 

4 

3 

t 

V> 

0:: 

< Ill 

0 

....J 2 ;;:: 

0 

c-. 

::r: 0.. 

150 

0 

Bikitaite and gas 

Dehydration interval 

at 10.3 mm · 

200 300 

XXX 

Petalite and eucryptite 

and gas 

X 

400 500 

FIGURE 413.2.-The decomposition of bikitaite under hydrothermal conditions. Circie=bikitaite unaffected, cross=bikitaite completely decomposed, circle and cross=bikitaite partially decomposed. 

diffraction pattern of the new phase are 4.70 (10}, 

3.27 ( 6), 2.97 ( 3), 2.44 ( 2). Other strong lines, if 

coincident with the lines of silica-rich ,8-eucryptite 

solid solution, are possible. 

It is not known if decomposition of bikitaite under 

hydrothermal conditions is preceded by dehydration. 

A simple projection of the decomposition curve under 

hydrothermal conditions suggests that dehydrated 

"bikitaite" should decompose in air above 390° C to 

eucryptite and petalite, but these products were not 

observed at any temperature from 390° to 800° C. 

Apparently at low H 20 pressure dehydrated "bikitaite" 

can be superheated metastably. 

At the same temperature and pressure at which 

bikitaite decomposes, natural spodumene remains unaffected either with or without H 20 present. However, 

spodumene has not been synthesized under the same 

conditions, so that the stability of spodumene and H 20 

relative to bikitaite is uncertain. The geological 

abundance of spodumene as the only lithium mineral 

in pegmatites where H 20 was almost certainly present 

suggests that bikitaite was less stable than spodumene 

under almost all conditions. 

Experiments on many lithium aluminum silicates 

indicate that equilibruim is especially difficult to attain 

below 500° C. Even though the equilibrium stability 
SHORT PAPE.RS IN THE GEOL·O~HC AND HYDROLOGIC SCIENCES, ARTICLES 293~4.35 D-357 

field for bikitaite, if any exists, cannot be established, 

the results given here show that bikitaite forms in 

nature only below 400° C. 

Bikitaite occurs with quartz and eucryptite (Hurlbut, 

1957, p. 793, fig. 1) and fresh ·contacts between quartz 

and eucryptite crystals are sho'"\'n. Hurlbut reported 

that eucrypt"ite appears to replace petalite and indeed 

the Bik.ita n.ssemblage suggests that petalite decomposes 

to quartz n.nd eucryptite under conditions at which 

bikitaite occurs. The quartz-eucryptite assemblage 

hn.s not been synthesized, and it is not known under 

what conditions it forms. Further laboratory. and field 

study of these ,quartz-lithium aluminosilicate assemblnges is desirable. 

DISCUSSION 

At a conference on zeolites at Pennsylvania State 

University in July 1959, a definition was proposed for 

zeolitesA. zeolite is 11 crystnllii1e uluminosilicnte with 11 tetrahedrally 

coordinated frnmeworl{ structure containing cavities with H20 

molecules, nllmli and alkaline earth ions. Consequences of these 

properties include t·eversible dehydration without destruction 

of the frameworl{ nnd ionic exchange capability. 

Reversible dehydration and very limited ionic exchange 

are here indicn.ted for bikitaite, even though the possible 

ionic exchange may be restricted to small ions by the 

size of the channels in bikitaite. These results together 

with Appleman's structure determination fulfill the 

requirements of the above definition and indicate that 

bikitn.ite should be cla.ssified as a zeolite. 

Crystalline hydrates and zeolites differ in dehydration behavior. The crystalline hydrates dehydrate over 

short temperature intervals and simultaneously undergo 

changes in crystal structure; complex hydrates may undergo many dehydration steps and structural changes. 

Zeolites dehydrate ov~r long temperature intervals 

while maintaining their structural identity. This study 

·of bikitaite demonstrates that there is no requirement 

for zeolitic dehydration to follow a smooth curve, even 

when only one H 20 n1olecule is present in each unit cell. 

Thi$ study demonstrates that measurements of the 

' equilibrium H 20 content of other zeolites during dehydration are desirable to define the role of H 20 in 

zeolite structures. 

Although an effective dessicant, partially dehydrated 

bikitaite has less H 20 adsorptive capacity at 25° C and 

10.3 mm H 2 0 pressure than is reported for equivalent 

weights of silica gel, alumina, or synthetic zeolite A by 

Breck and others (1956, p. 5968). This fact together 

with the rarity of natural bikitaite, the failure of any 

synthesis, the small size of the channels in the structure, 

and the relatively low upper limits of thermal stability 

argue against extensive practical lise for this mineral 

REFERENCES 

Appleman, D. E., 1960, The crystal structure of bikitaite, 

LiAlSi20o · H20 [ abs. 1 : Acta Cry st., v. 13, p. 1002. 

Breck, D. "'·• Eversole, ,V. G., Milton, R. M., Reed, T. B., and 

Thomas, T. L., 1956, Crystalline ZeoUtes-1, the properties 

of a new synthetic zeolite, type A: Am. Chern. Soc. Jour., 

v. 78, p. 5963-5971. 

Hurlbut, C. S., Jr., 1957, Bikitaite, LiAlSi20o· H20, a new mineral 

from Southern Rhodesia: Am. Mineralogist, v. 42, p. 792--797. 

-- 1958, Additional data on bikitaite: Am. Mineralogist, v. 

43, p. 768-770. 

Larsen, E. S., Jr., and Berman, Harry, 1934, The microscopic 

determination of the nonopaque minerals: U.S. Geol. Survey Bull. 848, 2nd ed., p. 30-82. 

Ruiz-Menacho, C., and Roy, Rustum, 1959, ·zeolite studies. 

II. Stability of the lithium zeolites [abs.J : Geol. Soc. 

America Bull., v. 70, p. 1666. 

414. GROUND-WATER SOURCES CONTAINING HIGH CONCENTRATIONS OF RADIUM 

By RoBERT C. ScoTT ~nd FRANKLIN B. BARKER, Denver, Colo. 

During the course of an investigation of the occurrence and distribution of uran.ium and radium in ground 

wa.ter of the United States (Scott and Barker, 1958) 

several areas were found where the concentrations of 

radium were unusually high. For purposes of this report, any concentration exceeding 3.3 pc per I (picocuries per liter; 1 pc= 10-· 12 curie) is considered unusually high. Concentrntions of several hundred picocuries 

per liter have. been observed in oilfield brines. Many 

samples containing large amounts of radium represen~ed thermal waters, brines, or water from mineralized zones, but a few samples were from fresh-water 

aquifers. The locations of sources of high-radium 

water are shown in figure 414.1. 

. The aquifers that yield waters high in radium are believed to be (a) formations of Cambrian and Ordovi-
D-358 GEOLOGLCAL SURVEY RESEARCH 1 9 61 

EXPLANATION 

Fresh-water 

~ sources 

EJ 0 

Brackish-water and brine sources 

FIGURE 414.1.-Location of ground-water sources containing high concentrations of radium. 

cian age in the north-central States, (b) the Roubidoux 

and Cotter formations in Kansas and Oklahoma, and 

(c) the Cheyenne sandstone member of the Purgatoire 

formation in southeastern Colorado. 

Unusually high concentrations of radium in water 

from formations of Cambrian and Ordovician age were 

first discovered in Iowa, and subsequent study has 

shown that the area involved covers a large part of the 

state. Lucas and Ilcewicz (1958) found high concentrations of radium in water from formations of Cambrian and Ordovician age .iil Illinois, and later work 

both by the present authors and by Lucas (1960) indicates an extension of the anomaly into Wisconsin. This 

area is the largest known in which the high concentrations of radium might be attributed to a single source. 

Samples from wells in the same formations in adjoining areas of northern Illinois, 'vestern "\tVisconsin, and 

central Minnesota do not show this anomaly, thus indieating a major change in the geochemical nature of 

these formations within a relatively short distance. 

Although the study of radium concentrations in water 

from aquifers of Cambrian and Ordovicia-n age in the 

north-central States is not complete, a consistent pattern seems to exist and some tentative conclusions can 

be drawn. Generalized contours of equal radium con-

.centrations are shown OI\ figure 414.2. Local anomalies 

in the aquifers cause a few wells in each area to yield 

water with a radium concentration higher or lower than 

the normal for the area; however, the general trend is 

quite pronounced and the boundaries, especially that at 

3.3 pc per I, are fairly sharp. The concentrations of 

radium generally increase in the presumed direction 

of water movement and may represent a slow flushing 

of the radioactive elements from the formations. The 

high radium concentrations found in brines from the 

more e~treme downgradient portions of these aquifers 

in Indiana might be additional evidence for such a 

flushing action. However, because the geochemical factors governing the occurrence of radi urn in brines are 

not well known, this evidence is not conclusive. 

The deep wells in this area generally obtain water 

from several different formations and it is difficult to 

determine which of the formations of Cambrian and 

Ordovician age contain the high-radium water. The 

3.3 pc per l isogram follows approximately the northern 

boundary of the area underlain by the. Maquoketa shale 
SHORT PAPEUS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293r-4.31

5 D-359 

44' 

40' 

) 

MISSOUitl '\. II,I,INOIS 

'\ 

L ~,o 100 wo MILes\,.."' 

I 

I 

I 

: I N ll I A N A II 

IO 

I 

( 

) 

I 

Fwum~ 41.4.2.-Area of investigation in the north-central States, 

with generalized contours of equal concentrations of radium 

(in picocuries per liter). 

and Orchard Creek shale (Sloss, Dapples, and 1\:rumbe.in, 1960). These formations probably exercise some 

control over the radiun1 concentrations either by serving as the source of radium to the underlying formations or by acting as aquata.rds that restrict circulation 

of water, thus preventing efficient flushing of the aquifers. A study of the radioactivity of cores from wells 

in the area probably will indicate the source of the 

radium and help resolve the question of the role of the 

l\{aquoketa a.nd Orchard Creek shales. 

Prelin1inary investigation of water from. the Cotter 

and Rouhicloux formations of Ordovician age in the 

tri-Stn,te area of Oklahoma, l(ansas, and Missouri suggest that lwre also the radium concentrations tend to 

increase .in the direction of water movement. Brines 

from these deeply buried Ordovician formations in 

Oklahoma contain some of the la.rgest concentrations 

of radium found in the country. Th~ anomaly appears to extend westward and south ward as far as the 

aquifers have been penetrated by wells. 

The Cheyenne sandstone member of the Purgatoire 

:formation of Early Cretaceous age commonly yields 

high-radium water throughout southeastern Colorado. 

Although not all samples of water from the Cheyenne 

contain high concentrations of radium, these anomalies 

are scattered throughout the area where the Cheyenne 

has been developed as an aquifer. This sandstone was 

derived from the Ancestral Rockies and deposited under 

continental conditions. It is overlain by the m·arine 

IGowa· shale member of the Purgatoire formation, 

which is impermeable enough to confii1e ground water 

in the Cheyenne sandston~ member under artesian pressure. It is not known whether the high concentrations 

of radium may be attributed to uranium minerals in 

the Cheyenne or were contributed by the IGowa or one 

of the underlying formations. 

Other occurrences of high-radium water are widely 

scattered ; some of these are known to be associated 

with uranium deposits, but some are isolated anomalies 

as yet unexplained. No detailed studies have been 

started in the other areas where radium anomalies have 

been found, but several interesting problems are posed. 

High radium concentrations have been found in water 

from the Floridan aquifer of Florida, McBean formation of South Oarolina, Jackson group in Arkansas, 

and Cockfield formation of Louisiana, all of Eocene 

age. These are all of the same general age; if the 

radium anomalies are found to persist throughout most 

of the areas of these formations, it will be evidence of 

quite similar environments and modes of deposition. 

Oil-field brines of the sodium-chloride type often contain radium in very high concentrations, but the geochemical aspects of this phenomenon have not been explained fully. 

REFERENCES 

Lucas, H. F., Jr., 1960, Study of radium-226 content of Midw.est water supplies, in Radiological. Physics Division semiannual report, Jan.-June, 1960: Argonne Natl. Lab. Rept. 

ANL-6199, p. 82-84. 

Lucas, H. F., Jr., and Ilcewicz, F. H., 1958, Natural radium-226 

content of Illinois water supplies: Am. "\Vater Works Assoc. 

Jour., v. 50, no. 11, p. 15·23-1532. 

Scott, R. C., and Barker, F. B., 1958, Radium and uranium in 

ground water of the United States, in Survey of raw material resources, United Nations 2d Internat. Conf. on 

Peaceful Uses of Atomic Energy Proc., Paper P /7778; 

London Pergamon Press, v. 2, p.1·53-157. 

Sloss, L. L., Dapples, E. C., and Krumbein, '\Y. C., 1960, Ordovician Malmoketa shale and Orchard Creek shale, in Lithofacies maps-;-an atlas of the United States and southern 

'Canada: New York, John Wiley and Sons, p. 9, map 14. 
D-360 GEOLOGICAL SURVEY RESEARCH 19 61 

415. CHEMICAL_ BEHAVIOR OF BICARBONATE AND SULFATE COMPLEXES OF MANGANESE 

By JOHN D. HEM, Denver, Colo. 

Manganese is normally present in natural water in 

the divalent state. The Mn+2 ion is capable of forn1ing 

ion-pairs, or complexes with each of the thr~ major 

anions present in most natural water, chloride, sul:fate, 

and bicarbonate. A number of six-coordinated manganous chloride complexes are known; however, they 

do not form in appreciable quantity unless the chloride 

concentration is 35,000 ppm (parts per million) or 

more. Chloride comple~es were not studied because 

they are considerably weaker than the bicarbonate and 

sulfate complexes. 

Ion pairs formed in the equilibria 

Mn+2+ HCOs-;;:::MnHCOs+ 

and 

are fairly stable and can exist in many natural waters. 

The equilibrium constant for the sulfate ion-pair given 

by Bjerrum, Schwarzenbach and Sillen (1958) is 

1.9 x 102 • The value given by these authors for the 

bicarbonate ion-pair is 3.0 x lOS. The latter value 

implies a very strong complexing effect from bicarbonate, and experimental work was done on the manganese 

bicarbonate ion pair. In this work it was assumed the 

simplest form of the complex, MnHC03+, was present. 

Systems containing an excess of powdered reagentgrade manganese carbonate, in contact with distilled 

water were brought to equilibrium at various partial 

pressures of carbon dioxide at 25°C. The resulting 

dattt. gave a value of 63 for the equilibrium constant 

(association constant) for the ion-pair MnHCOs•. 

This value appears reasonable when compared with 

constants for other metal ions of similar electronegativity (R. M. Garrels, written communication, 

1960). 

Manganese concentrations- present in surface or 

ground water rarely exceed a few tenths of ~ part per 

million. The effect of complex form~tion on a vailability of bicarbonate or sulfate is therefore negligible. 

From the relationships 

and 

[MnHCOa+] 

[Mn+2] 63[HCOa-] 

[MnS04aq.] 

[Mri+2] 1.9Xl02[S04 - 2] 

it is evident that half the manganese present will be in 

the form of the bicarbonate complex if the activity 

(effective concentration) of bicarbonate ions in solution 

is 940 ppm or if the activity of sulfate ions is 505 ppm. 

In most natural water both sulfate and bicarbonate 

are present and both the manganese complexes are 

present along with uncomplexed manga~ese ions. 

From the relationships 

MnHCOa++S04-~MnS04aq.+HCOa- for which the 

equilibrium constant is 3.1, 

and 

[MnHCOa+]+[MnS04] 2::[M · ] X 10_2 percent of Mn complexed, n species 

the net effects of various activities of sulfate and 

bicarbonate can be calculated. Figure 415.1 is~ graph. 

showing the proportions of manganese that would be 

complexed in solutions containing various activities of 

the two anions. It also shows which of the two 

complexes would be present in larger amounts. 

Water used for public supplies commonly contains 

between 100 and 1,000 ppm bicarbonate and between 10 

and 100 ppm sulfate, and as much as half of any manganese present could be in the complexed form in such 

water. Generally, however, the bicarbonate complex 

will predominate. 

It 'should be noted that the activity values used in 

preparing the graph are not identical with the actual 

concentrations that are reported in water analyses. An 

activity is an effective concentration and generally is 

lower than the corresponding measured concentration 

because of interionic attraction in solution and other 

factors. The difference between concentration and 

activity is small at low concentrations. For divalent 

ions such as manganese or sulfate, however, the activity 

may be only half as great as the concentration if the 

total dissolved solids content is 3,000 to 5,000 ppm. An 

approximate indication of complexing action can be 

obtained from figure 415.1 without making activity 

calculations. An exact evaluation of effects of complexing ,requires_ that activity coefficients be calculated. 

Standard methods of chemical thermodynamics can be 

used for this purpose. The writer (Hem, 1961) has 

described some of these procedures else_where. 

The total a1nount of manganese that can be retained 

in solution at equilibrium. is the sum of the different 
SHORT PAPERS IN THE GEOLOGIC AND. HYDROLOGIC SCIENCES, ARTICLES 293t-4,3,5 D-361 

SULFATE ACTIVITY, IN PARTS PER MILLION 

1 0 10 100 1000 10,000 ~·~--~--~--r-~~~~----~---r~~~~-r~~----~~--~~~~~rr~----,---.-~~-.~~1o,ooo 

90~----------------1------------------t--------------

80 

70 

60 z 

0 

::J 

....J 

50 1000 ~ 

Q: 

UJ 

40 a.. 

(f) 

1-

Q: 

c( 

30 a.. 

~ 

~ 20 > 

i= 

u 

c( 

UJ 

1-

c( 

10 z 100 0 

(J) 

Q: 

c( 

u 

iii 

PERCENT OF TOTAL MANGANESE COMPLEXED 

Fxounm 415.1.-Percent of total dissolved manganese present as complexes, and predominant form of complex at different sulfate 

and bicarbonate activities. 

ionic species that contain 1nanganese.. Under some 

conditions in nature, the amounts of dissolved manganese 1nay be greatly increased by complexing. In a 

solution where half the dissolved manganese is present 

as a complex, for example, the amount of manganese 

present jn solution may be double what might be expected in the absence of complexing. 

Manganese com.plexes may influence the behavior of 

the element in weathering or deposition reactions in 

nature in other ways. The complex ions of divalent 

manganese may tend to protect the manganese from 

604493 0-61-24 

oxidation to the +3 or +4 state, and may influence the 

rates of oxidation reactions. 

REFERENCES 

Bjerrum, Jannik, Schwarzenbach, Gerold, and Sillen, I... G., 1958, 

Stability constants of metal-ion complexes; Inorganic 

ligands, pt. 2: London, The Chemical Society Spec. Pub., 

no. 7, 131 p. 

Hem, J. D., 1001, Geochemistry of water-Calculation and use 

of ion activity': U.S. Geol. Survey 'Vater-Supply Paper 

1535-0, 17 p. 
D-362 GEOLOGICAL SURVEY' RESEARCH 19 61 

416. OVERVOLTAGE CHARACTERISTICS OF A PYRITE CRYSTAL 

By LENNART A. ANDERSON, Denver, Colo. 

Overvoltage phenomena at the surface of a metal in 

contact with an electrolyte are the principal cause for 

the anomalous induced polarizations in disseminated 

sulfide deposits. This investigation deals with the overvoltage effect on a pyrite crystal and the relation of 

overvoltage to current density at the polarizing 

interface. 

When a metal is placed in an electrolyte, a potential 

difference may be observed almost instantaneously between the metal and the electrolyte. The equilibrium 

potential across the metal solution interface is called 

the reversible electrode potential. When an external 

voltage is applied across the metal-electrolyte contact, 

the equilibrium potential will be disturbed, resulting in 

polarization of the electrode. A polarized electrode behaves irreversibly because some slow step in the electrochemical reaction at the electrode causes an unbalance 

in the electrode process. Because the energy requirements are greater in one direction than· in the other a . . ' potential Is generated that differs from the the equilibrium potential by a value determined by the current 

density and the nature of the electrode and electrolyte. 

This potential is called activation overvoltage. 

Another cause of overvoltage is the concentration 

change near the electrode as ions are either released or 

adsorbed by the electrode. Concentration overvoltage 

decreases as the concentration of the electrolyte is increased and can virtually be eliminated by agitation of 

the electrolyte. 

A false overvoltage is sometimes caused by an ohmic 

drop in potential due to oxide or grease films at the 

surface of ·the electrode. The use of very small currents 

and careful experimental procedure tend to minimize 

the ohmic overvoltage ( Glasstone, 1942, p. 435--440). 

The apparatus used to measure overvoltages in the 

laboratory is shown on figure 416.1. The solution must 

be boiled for a long period to remove the dissolved 

oxygen and other reducible material. Oxygen interferes with the electrode reaction, causing overvoltages 

to be erratic and nonreproducible. After it is cooled in 

a hydrogen atmosphere, the solution is forced into the 

- hydrogen-filled reservoirs using hydrogen as the pressure agent. 

Overvoltage measurements are made with the pyrite 

crystal·connected to the negative terminal of the current source. Current is passed from an external power 

supply into the soiution by means of a platinum electrode, through a salt bridge connecting the reservoirs 

electrically, and back to the power supply by way of 

the pyrite crystal. The voltage drop between the pyrite and a saturated calomel electrode is measured with 

an electronic potentiometer having an input impedance 

of 100 megohms. 

Overvoltages were measured with current densities 

at the electrode surface in the range 10- 7 to 10-s 

amperes per square centimeter. 

Previous investigations indicate a linear relation between overvoltage and the logarithm of current density 

(Butler, 1951, p. 161-.166). The overvoltage (~) 

has been observed to satisfy the expression 

a=a-b log j) 

where j is the current density in amperes per square 

centimeter and a and b are constants determined by 

the nature of the electrolyte and electrode. Bowden 

and Rideal ( 1928, p. 76) state that the relation holds accurately for mercury but only approximately for other 

metals. Butler (1951, p. 162) suggests that the value 

of b ranges from 0.09 to 0.13 in highly purified 

solutions. 

Bowden and Rideal ( 1928, p. 64) note that in pure 

electrolytes the overvoltage at a; given current density 

will reach its asymptotic value within 0.2 second after 

the start of current flow, but if oxygen is present even 

in very small quantities the saturation value will not 

be reached in less than 30 seconds. The decay rate is 

also affected by oxygen. Upon shutting off the external 

current, the overvoltage will fall to zero in 5 seconds 

if oxygen is present, whereas the decay will take 20 

minutes in oxygen-free solutions. Using this technique 

Solution plus .... __ 

hydrogen ,.. Salt bridge 

... Seale~ 

reservOirs 

\ 

\.sample mounted in lucile 

FIGURE 416.1.-Scbematic diagram of laboratory apparatus for 

overvoltage measurements. 

.• 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293~-4.3 5 D-363 

to check the purity of the electrolyte, it was found that 

1.5 seconds was required -to reach the saturation level 

and 14.5 seconds ela.psed 'during the return to the 

initial overvoltage value. Some impurities apparently 

are present, causing a deviation fr01n the ~nticipated 

straight-line relation. 

The results of the measurements on a pyrite sample 

in 0.01 N and 0.2 N H2S04 solutions and a 0.1 N KCL 

solution containing dissolved hydrogen are shown on 

figure 416.2. The ma.ximum current density normally 

u.pplied in a field survey would be at the point indicated 

by the value -6.0 for log j. The ovei·voltage behavior 

above this value is of interest because most laboratory 

measurements are made with very high current densities. At these current levels a small change in environment may cause a large variation in polarization response which may not be directly col:llparable to the 

polarization values measured in the ·field with loiw current density. 

-1 

The b value for the 0.01 N H 2S04 curve at low current 

density is 0.3, which is greater than the upper limit of 

the b values for pure solutions as indicated by Butler. 

The 0.2 N H 2S04 .and · 0.1 N KCl solutions have b 

values of 0.6 and 0.7, respectively, at the low current 

densities except that the KCl curve has a steep slope 

at the very beginning of current flow, possibly because 

of the deposition of the potassium ions in the immediate 

vicinity of the electrode. Each solution was probably 

somewhat contaminated, but this is unavoidable due 

to the impurities in natural pyrite crystals. The contamination indicator or slope b is not constant because 

a new surface is exposed by polishing the sample prior 

to each set of measurements. Polishing also alters the 

surface area in contact with the solution, which may 

account for the difference in the amplitude of the 

curves at the low current densities. 

The b value in each case in~reases when a current 

density of approximately 1 x 10-a amps per cm2 is 

-2~----------~----------~~----------._--------~----------~~--------~~--------~ -7.0 -6.5 -6.0 -5.5 -5.0 -4.5 -4.0 -3.5 

LOG 10 OF CURRENT DENSITY, IN AMPERES PER SQUARE CENTIMETER 

FIGURE 416.2.-0vervoltag~s of a pyrite crystal in sulfuric acid and potassium chloride electrolytes. 
D-364 GEOLOGICAL SURVEY RESEARCH 1 9 61 

102L_ __________________ ~----------~--------~--------------------~~------------------~ -7.0 -6;0 -5.0 -4.0 -3.0 

LOG10 OF CURRENT DENSITY, IN AMPERES PER SQUARE CENTIMETER 

FIGURE 416.3.-Specific surface resistances of a pyrite crystal in sulfuric acid and potassium chloride electrolytes. 

reached. At this point hydrogen gas forms at the electrode surface and causes a rapid rise in overvoltage. 

This continues until the surface is saturated with hydrogen atoms. As shown on figure 416.2, the electrode 

potential at which saturation is reached is a function 

of the number of hydrogen ions available for deposition. 

The significance of overvolta.ge to geophysical applications can be better illustrated (fig. 416.3) in terms of 

specific surface resistance ( overvoltage divided by current density). At very low current densities, the specific surface resistance is in the range of 1 x 105 ohmcm2. The resistance decreases as the current density 

is increased. Therefore, any increase in current density 

will cause the polarization voltage to decay through a 

smaller time constant, resulting in a proportionately 

smaller transient response. 

The data demonstrate that differences in the concentrations of the electrolyte have little effect on overvoltage at very low current densities, but that impurities within the pyrite crystal make overvoltage behavior difficult to predict. In induced polarizationfield applications, small currents give maximum transient response and r~asonably good reproducibility. 

REFERENCES 

Bowden, F. P., and Rideal, E. K., .1928, Electrolytic behavior of 

thin film; Part !-Hydrogen: Royal Soc. [London] Proe., 

ser. A, v. 120, p. 59-80. 

Butler, J. A. V., 1951, Electrical phenomena at interfaces: New 

York, MacMillan Co., 318 p. 

Glasstone, Samuel, 1942, Introduction to electrochemistry: New 

York, D. Van Nostrand Co., Inc., 557 p. 

... 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293t-43,5 D-365: 

GEOLOGY AND HYDROLOGY APPLIED TO ENGINEERING AND PUBLIC HEALTH 

417. SHATTER CONES FORMED BY HIGH SPEED IMPACT IN DOLOMITE 

By E. M. SHOEMAKER, D. E. GAULT 1 , and R. v. LuGN, Menlo Park, Calif., Moffett Field, Calif., and 

Menlo Park, Calif. 

Work done in cooperat·ion with the National .Aeronautics and Space .Administration 

Shatter cones are striated conical slip surfaces in 

rock, which have. been described from a number of 

widely scattered localities of unusual geological structui·e (Branco and Fraas, 1905; Shrock and Malott, 

1933; Rohleder, 1934; Dietz, 1959, 1960a, and 1960b). 

T'he cones are most commonly found in fine-grained 

carbonate rocks but have also been observed in shale, 

chert, quartzite, and granite. Dietz (1947, 1959, 

1960a) hn.s advnnced the hypothesis that all natural 

shatter cones hn. ve been formed by shock generated by 

the impact of large meteorites. 

Shatter cones are said to occur in strongly shocked 

beds of tuff around the Rainier nuclear explosion 

chamber in Nevada (Dietz, 1960a), but no conclusive 

evidence for the impact origin of natural shatter cones 

has been brought forward. During. the .course of recent work at ~1eteor Crater, Ariz., E.C.T. Chao found 

in alluvium on the rim of the crater a piece of Coconino 

sn,ndstone that exhibits part of a curved slickensided 

stu·face rudely resembling part of a shatter cone. This 

is perhaps the closest approach to independent evidence 

for the impact origin of shatter cones. 

Demonstration of the mechanisms and conditions 

under which shatter cones are formed would permit 

better evaluation of the confidence that may be placed 

in them n.s criteria for the recognition .of ancient largescnJe impact structures. It was, therefore, of more 

than ustml interest when, in a cooperative program of 

research on hypervelocity impact in rock between the 

Geological Survey n.nd the Ames Research Center of 

the Nn.tional Aeronautics and Space Administration, 

the first projectile fired produced small well-formed 

shatter cones in the rock target. Subsequent experiments at the Ames Research Center produced shatter 

cones in other targets, but none surpassed in clarity of 

form those produced by the first experiment. 

For this experiment, a block of fine-grained sandy 

dolomite.rock from the Alpha member of Mcl{ee (1938) 

of the l{aibab limestone of Permian age was collected 

1 Ames Research Center, National Aeronautics and Space Administration.. 

from a fresh roadcut near Meteo~ Crater, Ariz. The 

dolomite rock is composed of about 75 percent dolomite, 

20 percent quartz, and a few percent calcite, feldspar, 

clay minerals, hematite, goethite, and heavy minerals. 

According to measurements of C. H. Roach it has a 

grain density of 2.79 gm per cm3 , a dry bulk density 

ranging from 2.12 to 2.22 gm per cm3

, and 20.3 to. 23.8 

percent porosity. The acoustic velocity determined for 

one slab sawed from the block is 9,360+100 feet per 

second ( 2.86 km per sec) , and the unconfined crushing 

strengths of two l-inch, by l-inch, by 2-inch sawed 

samples measured with a standard testing machine were 

357 and 438 kg per cm2

• A smooth flat surface was 

prepared on one face of the block by a milling machine. 

Under the supervision of D. E. Gault a %6 -inch aluminum sphere was launched at high speed from a lightgas gm1 (Charters, Denardo, and Rossow, 1957) at the 

Hypervelocity Ballistic Range of the Ames Research 

Center. As determined from time measurements and 

spark photographs at four stations along the trajectory, 

the sphere struck the machined surface of the rock target at perpendicular incidence with a speed of 18,400 

feet per second ( 5.61 km per sec). 

The impact produced a crater in the dolomite rock 

5 em in diameter and 1.30 em deep and a surrounding 

annular spall 11 em across that just failed to break 

free (figs. 417.1 and 417.2). The color of the freshunshocked dolomite is grayish orange (10 YR 7/4), but 

most of the bottom of the crater was colored very pale 

orange ( 10 YR 8/2) to white, mainly as a consequence 

of intergranular crushing. 

Perched on the bottom of the crater were three easily 

recognized shatter cones and a number of striated slip 

surfaces of irregular or less definite form · (figs. 417.3 

and 417.4). OThe striated surfaces of the cones and 

other slip surfaces were colored pink evidently because 

of the smearing of the trace amount .of hematite along 

them. Within a few days the cones began to break up 

and spall, probably owing to internal stresses induced 

·by the impact. A rubber mold of the crater was made 

to provide a permanent record of the delicate features 
D-366 GEOLOGICAL SURVEY RESEARCH 1 9 61 

FIGURE 417.1.-Photograph of high speed impact crater in sandy 

dolomite from the Kaibab limestone. 

-o.oo 

0 2 3 4 CENTIMETERS 

0 2 3 INCHES 

CONTOURS SHOW DEPTH BELOW SURFACE OF BLOCK IN 

CENTIMETERS. CONTOUR INTERVAL 0 .25 CENTIMETERS 

FIGURE 417.2.-Map of high speed impact crater in sandy dolomite from the Kaibab limestone, by Andre Marechal and 

R. V. Lugn. Rectangle shows area covered by figure 417.4. 

FIGURE 417.3.-Photograph of part of high speed impact crater 

in dolomite showing shatter cones. Photograph by National 

Aeronautics and Space Administration. 

remaining in the crater, and the map of the shatter 

cones was subsequently prepared by R. V. Lugn from a 

plaster cast. 

The shatter cones range from 2 mm to 7.5 mm in 

exposed basal diameter. Apices of all but the smallest 

cone, which is about 1 mm high in the direction of the 

axis, were lost by spalling. Like natural shatter cones, 

the apical angles of the three experimentally formed 

cones are close to 90°. The axes of the cones are 

inclined toward the path of penetration of the projectile; the cones point approximately in the direction 

opposite to the shock propagation as hypothesized by 

Dietz (1947). Striations on the cones range from 0.2 

to 2.5 mm long, and troughs of the more conspicuous 

grooves are spaced about 0.1 to 0.2 mm apart. In general, the striations plunge more or less radially from 

the apices of the cones, but there is a distinct tendency 

for the striations to be parallel on the parts of the cones 

with least curvature. The trend of the striations in 

places changes abruptly where the curvature is sharp, 

a feature that is also observed on natural shatter cones. 

The net slip on the cone surfaces is difficult to estimate 

but it is prob:tbly less than 0.1 mm. 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 2.93!""""43,5 D-367 

0 5 10 ·MILLIMETERS 

~~~~--L-~~--L-~~-1 

EXPLANATION 

Fractur·c with !:lhcar di~:~plncement 

A 1'1'1111' ~1!1111.'~ dir••rli1111 of dip 

Upper limit of exposed slip surface 

Groove on slip surface showing 

direction of plunge 

----0.75---

Contour 

Number indicates dcpt.h below surface qf block in 

CCI!I.imeters. Contour interval 0.5 millimeters 

FIOVIUJ: 417.4.-Map of shatter cones and other slip surfaces in 

high speed impact crater in dolomite, by R. V. Lugn. 

From the geometry of the cones, it may be seen that 

displacement on the slip surfaces results in a distension 

or stretching of the rock in planes tangential to the 

front of the shock generated by the impact. This 

stretching may be easily understood as a consequence of 

the divergent .radial flow of material behind an approximately hemispherical shock front. The slip surfaces are evi~ently surfaces of maximum shear stress 

behind the shock front formed at about 45° to the radial 

directions of shock compression. We suggest that the 

cones point toward the origin of the shock because the 

slip surfaces are initiated around grains or small volumes that are slightly less compressible than the surrounding medium and are propagated outward as the 

shock advances. 

It is of interest to estimate .the peak shock pressure 

at the outer ra.dial limit of shatter cone formation in 

this experiment because of the possibility that shatter 

cones may serve as rough geological piezometers for 

peak shock pressures at ancient sites of meteorite impact. Initial shock pressure during the first stages of 

penetration of the projectile may be estimated from a 

one-dimensional analysis using the known impact 

velocity, measured densities of the target and projectile, 

the known hugoniot of aluminum (Altshuler and 

others, 1960),. and a hugoniot measured by R. Schall 

(written communication, 1960) for a rock with a 

density and porosity closely similar to that of the 

dolomite. This calculated pressure, 475 kilobars, may 

be· taken as the approximate peak pressure behind the 

shock into the rock at a moment when the shock has 

engulfed a mass of rock equal to that of the proj43ctile 

( 0.1592 gm). The shock energy at this stage will be 

roughly equally spread through the rock. engulfed and 

the projectile. If the energy remained evenly spread 

through the rock engulfed by the shock, the peak pressure would be inversely proportional to the mass engulfed and would have dropped to 14.8 kb at 1.30 em, 

the depth from the surface of the base of the most 

distant shatter cones. In reality, considerable energy 

will be trapped as heat in the region of high peak 

pressure arid as kinetic energy of the ejecta so that 

the peak pressure will decay approximately as some 

power of the inverse of the mass engulfed exceeding 1 

(pressure a[1/mass]n), probably between 4/3 and 5/3. 

Decay of the peak pressure according to the -4/3 

power of the mass gives a pressure of 4.7 kilobars at 

1.30 em and of 1.4() kilo bars according to the -5/3 

power of the mass. This may be compared with the 

measured unconfined static crushing strength of 0.43· 

kilobars. It should be noted that Grine and Fowles 

(1959) have reported that apparent dynamic compressive strengths of shock loaded rocks can be an order of 

magnitude higher than the static strengths. 

REFERENCES 

Altshuler, L. V., Kormer, S. V., Bakanova, A. H., and Trunin, 

R. F., 1960, Equation of state for aluminum, copper, and 

lead in the high pressure region: Jour. Experimental Theor~tical Physics, v. 38, p. 790-798 (in Russian) ; translation 

in Soviet Physics-JETP, v.ll, p. 573-579 (1960). 

Branco, Wilhelm, and Fraas, E., 1905, Das kryptovulcanische 

Becken von Steinheim : Akad. Wiss. ·Preuss. Abh., 64 p. 

Charters, A. C., Denardo, B. P., and Rossow, V. J., 1957, Development of a piston-compressor type light-gas .gun for 

the launching of free-flight models at high velocity: Natl. 

Advisory Comm. Aeronautics Tech. Note 4143, 95 p. 
D-368 GEOLOGLCAL SURVEY RESEARCH 19 61 

Dietz, R. S., 1947, Meteorite impact suggested by the orientation 

of shatter cones at the Kentland,· Indiana, disturbance: 

·Science, v. 105, no. 2715, p. 42-43. 

--1959, Shatter cones in cryptoexplosion structures 

(meteorite impact?) : Jour. Geology, v. 67, no. 5, p. 496-

505. 

--1960a, Meteorite impact· suggested by shatter cones ·in 

rock: Science, v.131;no. 3416, p.1781-1784. 

--1960b, Vredefort ring structur~an astrobleme meteor~ 

ite impact structure [abs.] : Geol. Soc. America Bull., v. 71, 

p. 2093. 

Grine, D. R., and Fowles, G. R., 1959, The attentuation of 

shock waves in solid materials with seismic applications, in 

Third symposium on rock mechanics: Colorado School 

Mines Quart., v. 54, no. 3, p. 251-269. 

McKee, E. D., 1938, The environment and history of the Toroweap and Kaibab formations of northern .Arizona and 

southern Utah: Carnegie Inst. Washington Pub. 492, viii, 

268 p. 

Rohleder, H. P. T., 1934, Uber· den Fund von Vergriesungserscheinungen und Drucksuturen am Kesselrand des kryptovulkanischen Bosumtwi-Sees, Ashanti: Centralblatt f. 

Mineralogie, Geologie und PaUiontologie, Abt. A, no. 10, 

p. 316-318. ' 

Shrock, R. R., and Malott, C. A., 1933, The Kentland area of 

disturbed Ordovician rocks in northwestern ll!d.iana: Jour. 

Geology, v. 41, p. 337-370. 

418. GEOLOGIC RESULTS OF NOVEMBER 1960 PROJECT CHARIOT HIGH-EXPLOSIVE CRATERIJNG 

EXPERIMENT, CAPE THOMPSON, ALASKA 

By REUBEN KACHADOORIAN, Menlo Park, Calif. 

Work done in cooperation with the U.S. A.tomiO Energy Commission 

In November 1960, a high-explosive cratering experiment was made at the Project Chariot site near Cape 

Thompson, northwestern Alaska, by rlte Lawrence Radiation Laboratory, Livermore, Calif., under ~uthorization of the Atomic Energy Commission. The experiment consisted of the detonation of a 256-pound 

spherical charge of TNT at a depth of 8.7 feet in the 

Tiglukpuk ( ? ) formation of Jurassic age. At ground 

zero the Tiglukpuk( ?) formation consisted of mudstone in beds having an average thickness of %, of an 

inch -and a maximum thickness of about 2 inches. The 

strike of the beds was fairly constant at N. 55° E.; 

however, the dip ranged from 80° SE to 70° NW and 

averaged 85° NW. As shown on figure 418.1, the mudstone was frozen. from the surface to a depth of 1.5 feet 

(frozen active zone) ; it was unfrozen from depths of 

1.5 to 4.0 feet (thawed active zone); and it was permanently frozen from depths of 4.0 to 9.0 feet (permafrost 

zone). Annual freezing 'and thawing had distorted 

and highly fractured the mudstone in the active zones. 

Most of the fractures in the frozen active zone were 

healed by ice, whereas fractures and joint planes in the 

thawed active zone were uncemented. Mudstone in the 

thawed zone was· more friable than the mudstone in 

the frozen zones. In the frozen active zone the moisture 

content was 3.1 percent; in the thawed -active zone, it 

was 3.6 percent; and in the permafrost zone, it ranged 

from 4.4 to 12.5 percent. Ice lenses and vugs were 

common in the permafrost zone. 

A nearly symmetrical crater 8 feet deep and 26 feet 

in diameter was produced by the explosion (fig. 418.1). 

The apparent volume of the crater was 78.5 cubic yards, 

and the volume of the debris on the lip of the crater was 

110 cubic yards (C. Bacigalupi, written communication, 1960), which gives the swell of the debris as 40 

percent. Debris was deposited in the crater, in an 

asymmetrical apron around. the crater, and as a finegrained fallout. Throwout as used in this report consists of material that followed ballistic trajectories to 

the site of deposition. Fallout consists of material 

arrested in its ballistic flight by atmospheric drag. The 

subsequent deposition was controlled by free fall and 

by atmospheric currents. The fallout did not contain 

any radioactive debris because a chemical explosive was 

used. The spatial distribution of debris is shown on 

figures 418.1 and 418.2. Only minor intermingling of 

debris of the different zones occurred in the crater. 

The average diameter of the area· covered by the 

throwout debris was between 800 and 900 feet (figs. 

418.1 and 418.2). The. minimum radius of the apron 

of throwout debris was about 350 feet in a northwest 

direction, which is the direction of the average dip of 

the beds. The maximum radius was 550 feet in a southeast direction, opposite the direction of dip. 

Three zones of debris were recognized in the apron 

(fig. 418.2) : an inner zone extending from the crater 

lip ~o about 45 feet from ground zero; an intermediate 

zone extending from about 45 to apout 250 feet from 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-4.3~ D-369 

Topography based on data supplied by 165 44 02 Geology by Reuben Kochodooricin 

Lawrence Radiation Laboratory, 

Livermore, California and U.S. 

Geological Survey, 1960 Post-shot topography 

Contour interval I foot 

A 

Ooshtld lin~s rtlprtJsent 0.2 foot contours 

Datum is/1::,. with assumed altitude of 100. 00' 

10 0 

Scale 

10 20 50f'EET 

EXPLANATION 

DEBRIS 

0 

Derived from frozen active zone 

Derived from thawed active zone 

68° 

06' 

II" 

Derived from permafrost zone 

BEDROCK 

Frozen 

-

active zone 

~.();:!\~{f/:~.:~:::1 Thawed octlv~ zone 

,,~~;;;;;,b·p.····'::·:;;j 

Permafrost zone 

----?-?-

Indefinite i::on·tact 

Queritld wh~rtl doubtful 

Crater lip boundary 

c 

Crater cen~er 

/1::,.100.001 

Reference station 

FIGURE 418.1.-Geologic map and sections of November 1960 Project Chariot high-explosive test. 
// 

I 

, ...... 

True 

Nr 

.,.--------

10° 

Chiefly fragments from 

- ............... :xermofrost zone 

. ......... 

.......... 

' " 

~ 6 1-

&.j(/) 

~ ~4 ~-u oz 

~ ~2 0 

&.1 

~ 0 

0 

\df \I dt + . 

d~-/-·,, ~ 

'~, -- ' \ ,. ' .-- ' · ...... _........ '-·-·..... ,--·-" \ .......... 

Debris 

frozen 

zone I ---,-....... ' 

/ '"- "\\Chiefly debris 

(rom_ thawed 

DISTANCE FROM GROUND ZERO ON AZIMUTH OF 10° 

act1ve zone 

\ 

280° \ \ 

I . I \ \ \ Crater \ \ I 

\ \ I 

Ground~\ \, \ / / zero "\. / / 

\ '- / I \\ '-j-- // 

NNW ' / ' / ' ......... ........... _ ....... 

850 0 ,_ ---~-- /55 \ . I 

Average 

Strike and dip 

\ I 

I I 

\ I \ ---r- Fallout 

\ I 

\ I 

\ I 

\ I 

\ I 

Arrow indicates wind direction at \ I 

Chariot Camp, 3700' west of ground '\ 1 

zero; wind velocity was 12 knots 

175° 

0 100 200 300 400 500 600 FEET 

·~ 

a; 6 I&J 

t-(J) 

&.II&J 

~54 

i 

I 

ldf t.l· dt t dp------~ . z 

~ - 2 t ',., ' / ,., '·...... ........... --·-....... _____ ...... ..... ----·, ', 

- •. I -·--·-- ~ .................. / \ :E 0 

o' 10o' 

I -·-- , 

2oo' 

I 

3oo' 

I 

4oo' 

I 

5oo 

~ 

55o' 

-z 0-

a; 

I&J 

~(/)4 :EI&J <:X: 

-o 

0 ~ 2 

Zz 

<-

0 

~ 00 

rL 

&.1 

1-

6 

~ :3 4 

<:X: 

0~ 

~; 2 

0-

&.1 

·, 

DISTANCE FROM GROUND ZERO ON AZIMUTH OF 100° 

~----dt + ·dp~ ? .,., .......... - ...... 

,.-----?-..... '·- . ..... -..-·' . ..... . ..... ..... . ' 

100 200' 30d 40o' 

DISTANCE FROM GROUND ZERO ON AZIMUTH OF 175° 

~~: r--dt 

'· ', ·--· \. , .... 

' ' 500' 

~ 0 . . d 

DISTANCE FROM GROUND ZERO ON AZIMUTH OF 280° 

FIGURE 418.2.-:Map showing distribution of throwout and fallout debris and graphic depiction of size distribution of throwout debris. 

1:::1 

I 

~ 

'-1 

0 

0 

t::r:.i 

0 

~ 

0 

0 

s 

> 

~ 

~ 

~ t::r:.i 

~ 

=:c 

t::r:.i 

r:Jl 

t::r:.i 

> 

=:c 

~ 

.... 

~ 

C) 

.... 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293t-43,5 D-371 

ground zero; and an outer zone extending from about 

250 feet from ground zero to the maximum distance of 

throwout ( 550 feet). 

The rocks in the inner zone were derived from the 

frozen active zone and consisted of debris that was 

mostly overturned and ,had traveled only short distances. The largest boulder noted was in this zone and 

had the dimensions 5 x 4¥2 x 1¥2 feet. The frozenunfrozen interface, 1.5 feet below the surface, controlled one dimension of the fragments .derived from 

the frozen active zone. No fragment with a minimum 

dimension larger than 1.5 feet was noted. Although 

most of the large fragments were overturned and had 

moved short distances, the top 2 to 3 feet of concrete 

used to plug the hole in which the explosive was placed 

landed 335 feet from ground zero·on an azimuth of 185°. 

Throwout debris in the intermediate zone consisted 

chiefly of material derived from the thawed ~ctive 

zone. The thickness of debris was much less than that 

of the debris derived from the frozen active· zone, and 

the median diameter of the fragments was much less 

than that of fragments obtained from the overlying 

and underlying frozen rock zones. This was to be expected because the rocks of the thawed active zone were 

not ce1nented by ice and were somewhat more friable 

than the frozen rocks. 

Rock fragments in the outer throwout zone were derived chiefly from the more massive mudstone beds of 

the permafrost zone. The median diameter of the fragments was larger than that of the debris in the intermediate zone, but smaller than that of debris in the 

inner zone. However, the number of fragments was 

much lower. Beyond 300 feet from ground zero, only 

sporadic fragments were noted. 

The pattern of deposition of the fine-grained fallout, 

consisting of nonradioactive particles less than 2,000 

microns in diameter as determined by K. H. Larson 

(written communication, 1961), was controlled by the 

direction of wind, which at the tilne of detonation was 

from the north-northwest (340°) and had a velocity of 

12 knots. Fallout debris was seen only south of ground 

zero (fig. 418.2). The fallout debris was noted as far 

as 875 feet from ground zero on an ~zimuth of 175°; 

the fallout belt was about 215 feet wide, 550 feet from 

ground zero. The material comprising the fallout consisted chiefly of mudstone from the thinner beds. The 

zone or zones (frozen active, thaw~d active, and permafrost) from which the debris was derived is unknown. 

The average height of the cloud due to the detonation 

was about 190 to 200 feet and the width was approximately 175 feet. However, in the center of the cloud a 

streamer about 30 feet wide rose to a height of approximately 250 feet. This streamer probably marked the 

trajectory of the concrete plug that landed 335 feet 

south of ground zero. 

419. ENGINEERING GEOWGY PROBLEMS IN THE YUKON-KOYUKUK LOWLAND, ALASKA 

By FLORENCE RoBINSON WEBER and TROY L. P:Ew:E, College, Alaska 

Engineering geology problems . in the Yukonl(oyukuk lowland, west-central Alaska (fig. 419.1) 

are concerned mainly with flooding, source of aggregate, 

and poor foundation conditions caused by seasonally 

and perennially frozen ground. The lowland is approximately 100 miles long and 40 miles wide, and is· 

bounded by rounded hills i,OOO to 2,000 feet above the 

flood plains of the major rivers. The area was not 

glaciated in Pleistocene time but was subject to alternating periods of great deposition and erosion. Unconsolidated deposits of Quaternary age are more than 

300 feet thick in places, although locally a few bedrqck 

knobs project above the alluvium. 

Two large rivers, the Yukon and Koyukuk, meander 

across the low land. The flood plains are covered by a 

mosaic of tundra and forest interspersed with a complex 

of sloughs, meander scars, oxbow lakes, swamps, and 

creeks. For mapping purposes the surficial deposits 

have been subdivided into 6 map units-2 terrace units, 

and 4 flood plain units-which may- be distinguished 

largely on the basis of ice and organic content, topographic expression, vegetation, and to some extent 

lithology. Engineering geology problems differ in 

degree or kind in the various units. 

The two terraces range in height above the flood 

plains from 30 to 250 feet. They are formed of perennially frozen gray silt and sand with variable amounts 

of organic matter and include masses of ground ice--

vertical and inclined ice dikes or wedges :!4-inch to 3-

feet wide and 3 to 15 feet high (Pewe, unpublished 
D-372 GEOLOGLCAL SURVEY RESEARCH 1961 

0 

YUKON 

TERR 

GULF OF ALASKA 

0 100 200 300 400 MILES 

FIGURE 419.1.-Index map of a part of Alaska showing the location of the Yukon-Koyukuk lowland. 

data). The terrace8, which differ from each other only 

in relative height, are poorly drained and are covered 

with a myriad of steepsided thaw lakes, ponds, and 

swamps. Polygonal ground and braid~d streams are 

common. Mosses, sedges, low brush, stunted black 

spruce, and (rarely) birch grow on these frozen silts. 

Foundation conditions on both of the terraces are poor. 

Breaking of the insulating tundra can result in a summer quagmire and the ground will subside because of 

the thawing of ice masses. The poorly drained finegrained sediments are also susceptible to intense seasonal frost heaving. 

In the northern part of the low land the terraces are 

commonly covered by alluvial sand, which in many 

places forms dunes. The sandy areas are well drained, 

free of large ground-ice masses and thaw lakes .. The 

dunes are largely inactive and support an open forest 

of aspen, birch, and spruce. Foundation construction 

conditions on the ice-free sandy zones are fair ·although 

slopes in dry sand are unstable. 

The flood-plai_n map units-"linear," "advanced 

linear," "coalescent," and "scalloped"-represent four 

arbitrary phases in the development of the flood plain 

(fig. 419.2). This area has been cited as a classic example of the development of a flood plain by meandering rivers under subarctic conditions (Pewe, 1947), and 

the classification 'Of these flood plain units has been 

extended successfully to the flood plain of the Kuskokwi~ River (Drury, 1956). The linear phase is the 

first formed and the scalloped is the last. The four 

units can be distinguished on the basis of the shape of 

the lakes, vegetation, and· the amount of ice and organic 

material they contain. The foundation qualities o~ the 

units vary largely with the amount of ground ice 

present. The first phase of development, the linear 

unit, is made up of gray micaceous silt and sand forming slipoff slopes, islands, and other 'low ·areas most 

recently occupied by rivers. Linear, "point bar" lakes 

are present and an integrated drainage is lacking. 

Permafrost is absent or discontinuous; no large ground 

ice masses are present. Vegetation is made up mostly 

of grasses, Equisetrum, ·alder, willow, and some large 

cottonwood and spruce trees. This unit is fairly good 

for foundation purposes but is subject to flooding, river 

cutting, and icing. The only gravel suitable for aggregate that is present at the surface in the lowland is 

found sparingly in this unit. 

The second flood-plain map unit, marking the advanced linear phase, is lithologically similar to the first. 

Elongate ·lakes, partially broken into segments by encroaching vegetation, and discontinuous permafrost 

(with no large ice masses) are characteristic of this 

phase. Relatively large birch and spruce with a 

brushy understory grow on the unit. Although the 

unit is fairly good for foundation purposes, it is also 

subject to seasonal flooding. 

Broad swampy areas adjacent to the large rivers 

which are marked by coalescing linear lakes form the 

third unit or coalescent phase of the flood plain. Large 

ground-ice masses are present in the organic silt, and 

melting of these masses results in the partial coalescence 

of the linear lakes. Mosses, cottongrass tussocks, cranberry, al<;ler, stunted spruce, and birch grow here. The 

unit is poor for construction as it is very wet and subject to intense frost heaving and to subsidence upon 

thawing of permafrost. Areas underlain by this unit 

may be inundated in flood stage. 

The last unit of flood plain development is the 

scalloped phase. Lakes have lost their linear shape, 

are rounded, and have scalloped edges. Ice wedges 

and many large masses of ground ice are characteristic 

of this stage. In general, drainage, ground ice, an~ 

vegetation characteristics are similar to those of the 

adjoining terraces but the unit lies near enough to river 

level to be flooded occasionally. Because of poor drainage, susceptibility to intense frost heaving, and the 

presence of large ground-ice masses, the unit is very 

poor for foundations or construction of any sort. 

Precise dating of the units in the area is not yet 

possible~ However, .bones of extinct Pleistocene mammals (Mammoth) have been found in deposits of the 

oldest terrace. A carbon-14 date of 8,140+300 years 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIEN·CES, ARTICLES 293>--435 D-373 

FIGURE 419.2.-High-altitude oblique aerial photograph looking south toward the junction of the Yukon and Koyukuk Rivers. 

The Koyukuk River (dark color) joins the silt-laden Yukon River (light color) at the right. Flood-plain units indicated by 

number are the (1) linear phase, (2) advanced linear phase, (3) coalescent phase, and (4) scalloped phase. Unit {5) is 

the high terrace. Photograph by U.S. Army Air Corps, August 24, 1941. 

(W--472) (Rubin and Alexander, 1958, p. 1479) was 

obtained from organic material taken from the scalloped phase of the flood plain. Therefore, the formation of much of the modern flood plain postdates this 

time; cutting of the terraces took place prior to this 

date. Eolian reworking of the sand on the terraces has 

persisted until the pr'fent, as indicated by a small area 

of active dunes north' of the Koyukuk River. 

REFERENCES 

Drury, W. H., Jr., 1956, Bog flats and physiographic processes 

in the upper Kuskokwim Hh·er region, Alaska: Harvard 

Univ. Gray Herbarium Contr., no. 178, 130 p. 

Pewe, T. L., 19±7, Permafrost and geomorphology in the lower 

Yukon River valley [Alaska] [abs.] : Geol. Soc. America 

Bull., v. 58, no. 12, pt. 2, p. 1256. 

Rubin, Meyer, and Alexander, Corrinne, 1958, U.S. Geological 

Survey radiocarbon dates IV: Science, v. 127, p. 1476-1487. 
D-374 GEOLOGICAL SURVEY RESEARCH 19 61 

420. HYDROLOGY OF RADIOACTIVE-WASTE DISPOSAL AT THE IDAHO CHEMICAL PROCESSING PLANT, 

NATIONAL REACTOR TESTING STATION, IDAHO 

By PAUL H. JoNES; Idaho Falls, Idaho 

Work done in cooperation with the Idaho Operations Office, U.S. Atomic Energy Commission. 

Low-level aqueous radioactive waste (less than 10-4 

microcuries per milliliter, gross beta-gamma) is 

pumped directly into the ground-water reservoir at the 

Idaho Chemical Processing Plant (ICPP) through a 

drilled, cased, gravel-packed well 598 feet deep. This 

well penetrates several thin basalt flows and a single 

thin bed of silt, sand, and gravel below the water table, 

which occurs at a depth of about 460 feet. Radioactive 

waste is diluted with warm nonradioactive water from 

plant wastes, including large amounts of sodiumchloride brine from water-softening units. Since 

1952, 757 curies of activity have been disposed to this 

well in 2,495,450,000 gallons of water. The annual rate 

of disposal is summarized in table 420.1. The hydrology of basalt aquifers is difficult to interpret because of 

the sheet-conduit nature of the aquifers, the very low 

gradients in head, and the difficulty of establishing local 

stratigraphic and hydraulic continuity, but geophysical 

logging has resulted in identification, description, and 

correlation of aquifers. Well-packing equipment has 

enabled isolation and testing of aquifers. 

During the period 1953 through 1959, 15 intercept 

wells 6 inches in diameter were drilled by percussion 

methods to depths ranging from 570 to 730 feet. Of 

these, 9 are uncased below the water table. Several 

persons made detailed studies of the lithology of beds 

penetrated and 'of the chemical and physical quality of 

water from selected depths in the wells. Water-level 

TABLE 420.1.-Volume and curies of liquid waste discharged to 

ICPP disposal well 

Year 

1953 ______________________ _ 

1954 ______________________ _ 

1955 ______________________ _ 

1956 ______________________ _ 1957 ______________________ _ 

1958 ______________________ _ 

1959.-----------~---------- 1960 ______________________ _ 

Thousands of 

gallons 

396,000 

229,838 

396, 175 

351,314 

230,747 

373, 151 

328,225 

190,000 

TotaL _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 2, 495, 450 . 

Curies 

15 

8 

15 

16 

285 

339 

47 

32 

757 

0. 15 

. 03 

. 04 

. 04 

. 01 

. 02 

. 38 

. 00 

0. 67 

measurements were made in intercept wells, and hydraulic tests were conducted in the ICPP supply wells. 

Gamma-ray logs were made for wells 3i to 44, and 

flow.:meter logs for wells 40 to 48 (fig. 420.1). Results 

of aquifer tests have been described by Walton and 

Stewart ( 1959) ; results of other tests are not published. 

In 1960 the network of intercept wells was broadened 

by drilling wells 51, 52, 57, 59, and 67 (fig. 420.1). 

Borehole geophysical logging has provided data that 

serve to identify the aquifers tapped and to describe 

some of their characteristics. Hole-diameter (caliper) 

logs indicate that the boreholes are enlarged where interbeds of scoria, cinders, flow breccia, and sedimentary 

rocks occur between dense basalt flows. Such interbeds are the principal aquifers. Sedimentary interbeds 

are identified by gamma-ray logs, the radioactivity intensity of the sedimentary rocks being markedly greater 

than that of basalt. Gamma-ray intensity logged in 

enlarged sections of the hole below the water table is 

reduced by the shielding effect of the water. The cross 

EXPLANATION 

--·to 

Thickness of ."540-foot" 

aquifer 

Interval 5 feet 

-20 

Sodium content 

Interval I 0 ports per million 

0 

39 

045 

Intercept well 

67 

0 

FIGURE 420.1.:.-Thickness of the "540-foot" aquifer and sodium 

content of water from wells in the vicinity of the Idaho 

Chemical Pr6cessing Plant, 1960. 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTLCLES 2 9 3....-4 3.5 D-375 

section, figure 420.2, shows the correlation and lithology 

of the significant aquifers. The "540-foot" aquifer has 

been mn.pped throughout the ICPP area and is believed 

to be the most important aquifer above a depth of 700 

feet in this area. 

Logs of water resistivity and temperature show the 

depths at which saline waste water from the disposal 

well. enters and leaves the intercept wells. Figure 

420~2B illustrates the· vertical spread of waste water 

with distance from the disposal well, and the decrease in 

NORTHWEST 

4400' 

4300' 

4200' 

GAMMA· RAY 

INTENSITY, IN 

mr/hr 

NORTHWEST 

WATER 

RESISTIVITY, IN 

OHM-METERS 

14 18 22 

Well 

43 

Well 

43 

HOLE 

DIAMETER, IN 

INCHES 

WATER 

TEMPERATURE, IN 

DEGREES FAHRENHEIT 

52 56 60 

Well 

47 

Well Well 

GAMMA· RAY 

INTENSITY, IN 

mr/hr 

Well 

47 

HOLE 

DIAMETER, IN 

INCHES 

GAMMA· RAY 

INTENSITY, IN 

mr/hr 

A. 

49 

Well 

49 

HOLE 

DIAMETER, IN 

INCHES 

WATER WATER . WATER WATER 

RESISTIVITY, IN TEMPERATURE, IN RESISTIVITY, IN TEMPERATURE, IN 

OHM-METERS DEGREES FAHRENHEIT OHM·METERS DEGREES FAHRENHEIT 

12 16 20 56 tiO 14 is 52 56 60 

GAMMA· RAY 

INTENSITY, IN 

mr/hr 

59 

HOLE 

DIAMETER, IN 

INCHES 

Well 

59 

WATER 

RESISTIVITY, IN 

OHM-METERS 

14 18 

WATER 

TEMPERATURE, IN 

DEGREES FAHRENHEIT 

52 56 

4400' _ _ Tcm_ot 5 d' -: - - .!L.!ruwt~ - - bee~ 

--=--=--== --==--- ---

4300' 

4200' 

EXPLANATION 

~ 

1:::::1 

Clay 

Silt and sand Scoria 

lifE! III!] 

Silt and Dense basalt 

cinders 

--.. ·.~· .. - --- __ - -__ --- =------==. =-= .":· :': ~ 

0 400 800 FEET 

DATUM IS MEAN SEA LEVEL 

B . 

SOUTHEAST 

4400' 

4300' 

4200' 

SOUTHEAST 

4400' 

4300' 

4200' 

.I!'IOURE 420.2.-Cross section through wells in the vicinity of Idaho Chemical Processing Plant. A, gamma-ray intensity 

and ·hole diameter; B, temperature and electrical resistivity of water. Location of wells shown on figure 420.1. Vertical 

scnle is in feet above sea level. 
D-376 GEOLOGLCAL SURVEY RESEARCH 1 9 61 

temperature and salinity away from the disposal well. 

The thickness of the "540-foot" -~uifer in the ICPP 

a~ea is shown on figure 420.1. The thickness indi<:?ated 

by the contours is that thickness in which the diameter 

of the drill hole is more than 2 inches larger than the 

diameter of the hit used in drilling. Waste water from 

the disposal well tends to move from thin to thicker. 

parts of the aquifer. One preferred direction of movement is southwest, toward well45, and another is southeast, toward well 49. Flow southward tends to veer 

to the east or west, and no appreciable flow reaches the 

vicinity of well 51. 

The average sodium content of water from intercept 

wells in the ICPP area in 1960 is shown on figure 420.1. 

Two "lobes" of higher salinity occur, corresponding to 

the areas where the aquifer is thickest; one trends southwestward past well 47 toward well 57, and the other 

trends southeastward past well 49. Minimum salinity 

occurs at well 51. A sharp decrease in ·salinity westward from well 42 may be the result of channeled 

through-flow of ground water, and the gradual decrease 

in salinity eastward may indicate that the aquifer 

pinches out in that direction. 

Vertical flow between aquifers tapped by_ intercept 

wells results in an erratic distribution of waste water 

in the ground-water reservoir and makes measurements 

of water level in the well useless for quantitative purposes. Effective study of vertical flow requires reconstruction of intercept wells so that they tap but one 

aquifer. Where this has been done using modified oilwell packers, head differences between aquifers generally are less than 1 foot, but differences of 70 to 80 

parts per million of chloride occur in waters from different aquifers tapped by the same well. 

REFERENCE 

Wa!ton, ,V. C., and Stewart, J. ,V., 1959, Aquifer tests in the 

Snake River basalt: Jour. lrrig. and Drainage Div., Proc. 

Am. Soc. Civil En!Pneers, v. 85, no. IR3, paper no. 2156, 

Sept., 1959. 

421. DISPOSAL OF URANIUM-MILL EFFLUENT NEAR GRANTS, NEW MEXICO 

By S. W. WEsT, Albuquerque, N. Mex. 

Worlc done in cooperation with the New Mewico State Engineer 

Disposal of uranium-mill eflluent at The Anaconda 

Co. Bluewater Mill~ 9 miles northwest of Grants, N. 

Mex., became a problem in a relatively short time after 

the mill was built in 1952. A typical-chemical analysis 

of eflluent is shown in table 421.1. 

The use of an evaporation pond in·a natural depression and much research by The Anaconda Co. on impervious pond linings and on other methods of surface 

disposal indicated that surface methods of disposal 

might contaminate the potable ground water. The 

company then investigated the possibility of injecting 

the waste fluids into an unused aquifer that contains 

non-potable water and is below, and isolated from, the 

principal sources of ground water in the area. Early in 

1959 a deep test well for underground disposal was 

drilled in the NE1JI,SW1;{ sec. 8, T. 12 N., R. 10 W. 

The Geological Survey ·and the New Mexico State 

Engineer cooperatively observed the drilling, logged 

cores, observed drill-stem tests and well eompletion 

work, and observed initial withdrawal and injection 

tests. 

The general geology in the vicinity of the mill and 

disposal well is shown on figure 421.1, and the stratigraphic units that were penetrated are shown on a 

diagram of the well, figure 421.2. 

The San Andres limestone (Permian) is the principal aquifer, and water from it is used for domestic, 

municipal, industrial, and irrigation supplies. Wells 

that tap the San Andres yield as much as 2,800 gpm 

(gallons per minute), and the specific capacity of wells 

ranges from 10 to 1,100 gpm per foot of drawdown. 

Although few wells are completed in the Glorieta sandstone (Permian) , it is a source of potable water that 

leaks upward into the San Andres in areas of large 

withdrawal. The gradient of the water table in the 

San Andres and Glorieta is to the east and southeast. 

Dissolved solids in the water from the San Andres 

range from 350 to 2,200 ppm (parts per million). The 

most critical chemical constitutent is sulfate, which 

ranges in concentration from 120 to 830 ppm. 

Alluvium and basalt along the Rio San Jose form an 

aquifer of secondary importance. Most of the water 
SHORT PAPERS IN THE GEOLOGIC AN:D HYDROLOGIC SCIENCES, ARTLCLES. 293~4 5 D-377 

R . 11 W . R. 10 W . 

0 2 3 MILES 

EXPLANATION 

~ 

~ 

Alluvium 

Silt, clay, sand, and gravel 

~ 

~ 

Basalt Dense to vesicular basalt; may overlie or intertongue with alluvium 

f"C_:§tt :...] 

Landslide and talus material 

~I Spring-deposited limestone 

Extrusiv

~ e rocks Mainly basalt flows capping 

hig h mesas 

II 

Chinle formation Siltstone, mudstone, and conglomeratic sandstone 1i cm , middle part 

1i cl, lower par t 

San Andr

~ es limestone Limestone, sandy limestone, and 

limy sandstone 

m 

Glorieta sandstone Well-sorted, medium-grained 

sandstone 

Y eso formation Mudstone, siltstone, sandstone, 

limestone, and anhydrite 

Contact 

0 

u -----7 ... Fault · Dashed w here approximately located 

or doubtful; dotted w here covered 

by alluvium or basalt; queried 

where buried location doubtful. U, 

upthrown block ; D, downt hrown 

block 

r:··-- ------------ -, 

'-.,_ 

>-

0:: 

<{ 

z 

0:: 

w 

1-

<{ 

::J 

0 

l! 

~ 

z 

<{ 

::E 

0:: 

w 

0.. 

FIGURE 421.1.-Geologic map of the Grants-Bluewater valley, Valencia County, N. Mex. 

from the 'alluvium and basalt is used for domestic and 

municipal supplies. The water in the alluvium and 

basalt moves down the valleys approximately parallel 

to the Rio San Jose and its principal tributaries. 

Other aquifers are utilized for only small supplies 

of water, mainly for stock. The only wells that tap 

the Yeso formation (Permian) are near its outcrops 

several miles upgradient from the disposal well. 

604493 0-61-25 

The disposal well was drilled to a depth of 2,511 feet 

and was cored continuously below 445 feet. Many 

drill-stem pressure tests and swabbing tests were made 

as the hole was cored. A sample of water collected 

from the Meseta Blanca sandstone member of the Yeso 

formation in the interval from 1,305 to 1,450 feet in the 

test well contained 4,130 ppm of dissolved solids and 

2,170 ppm of sulfate. This zone and thin zones of 
D-378 GEOLO(UCAL SURVEY RESEARCH 1 9 6 1 

..,.:: 

c::o 

2~ 

Q; 0 

·~~ 

""'<> 

c: 

0> " -;;; 

j .:: 

<") 

0 ~ .,-g 

E: ~ e 

.2 0 .. 

"'"' 0. Cl. 

Top of 6%-inch casing Zero datum (elevation 6689.75 It) 

(elevation 6684.14 It)\ _j Ground level (elevation 6681.53 It) 

Cement 

Static water level 

(elevation 6452 ft) 

13%-inch casing 

8%-inch casing 

6%-inch casing 

17'/•·inch hole 

!l-inch hole 

H~·inch hole 

Lower member of Chinle formation 

Mudstone, sandstone, and 

conglomerate 

360 It 

San .Andres limestone and Glorieta 

sandstone, undivided 

577 It 

San Ysidro member of Yeso formation 

Mudstone, siltstone, sandstone, 

limestone, and anhydrite 

1304 It 

Meseta Blanca sandstone member of 

1474 11 Yeso formation 

Sandstone 

Abo formation 

Mudstone, siltstone, sandstone, and 

conglomerate 

2244 It 

Madera(?) limestone 

Mudstone, limestone, ond 

conglomerate 

2439 ft Schist Total depth -.......lo<......c..-"-----L 2511 ft 

z 

c( 

z 

~ ~ z 

z 

UJ 

0.. 

FIGURE 421.2.-Diagram of The Anaconda Co. disposal test well 

in the NE14SW14 sec. 8, T. 12 N., R. 10 W., 9 miles northwest of Grants, N. Mex. All depths are below zero datum. 

Hole diameter not to scale. 

TABLE 421.1.-A.na.Zysis of efftuent jr01n The Anaconda Oo. 

Bluewater uranium mill 

Chemical constituents : 1 Parts per million 

Chloride ( Cl) ---------------------------- 1, 350 

Sulfate (SO.)---------------------------- 6, 450 

Nitrate (NOs)---------------------------- 100 

Sodium (Na) ---------------------------- 1,.050 

·Calcium ( Ca) ---------------------------- 550 

Magnesium (Mg)_________________________ 550 

Iron (Fe)------------------------------- 350 

Manganese (Mn)------------------------- 450 

Total dissolved solids___________________ 11, 000 

Radiological constituents: 2 Microcuriea per milliliter 

Gross alpha______________________________ 2. 43 X 104 

Uranium-natural ---,--------------------- 1. 61 X 10-6 

Thorium-230 ---------------------------- 2. 70 X 10-~ 

Radium-226 -~--------------------------- · 6. 62 X 10-7 

1 Average of four samples of filtered influent to disposal well, pH 2.7; 

samples collected between December 1, 1959, and March 30, 1960; 

analys.es by The Anaconda N~w. Mexico Operations Chemical Laboratory. 2 Composite of. samples collected dally i'r()m January 20 to 31, 1960; 

analysis by TracerJ.ab, Inc. 

sandstone between 950 and 1,423 feet form the injection 

interval. 

Beds of dense mudstone, limestone, anhydrite, and 

gypsum between the base of the Glorieta sandstone and 

the highest injection zone were expected to prevent the 

movement of water upward into the Glorieta and the 

San Andres limestone. Many fractures in the cores 

from this interval were observed, but nearly all were 

sealed tightly with gypsum. The annuh"Lr spaces between the· casing and the wall of the hole and between 

the strings of casing (fig. 421.2) were cemented and 

tested by using air pressure. The pressure tests indicated a tight seal. 

The casing was gun-perforated adjacent to penneable 

zones in the interval from 950 to 1,423 feet. The perforations are lf2-inch and %6 -inch in diameter, and 261 

shots were fired in the injection interval. Several 

zones below 1,423 feet also were perforated and tested, 

but none took water. 

The altitude of water level was 6,452 feet in the disposal well after the San Andres and Glorieta formations were cased off and before injection of fluids into 

the Y eso formation was started. A drill-stem pressure 

test of the San Andres and the Glorieta indicated the 

same altitude of water level for these units. A 

monitoring well was drilled to the base of the Glorieta 

sandstone 300 feet southeast of the disposal well, and the 

altitude of water level in it was 6,452 feet. The same 

water level in the two aquifers was first interpreted as 

an .indication of vertical hydrologic continuity. 

There are many faults in the region (fig. 421.1), and 

it was feared that fractures in the fault zones might be 

conduits through which water could move from one 

formation to another. It seemed possible, also, that 

permeable beds might be offset against impermeable 

beds forming barriers to lateral movement of water 

away from the injection well and causing excessive 

buildup of hydraulic pressure in the disposal zone. 

The initial injection test indicated th.at vertical leakage 

was negligible and that one or more faults are barriers 

to lateral movement of the water. Temporary cessation of injection at critical times during the test period 

opscured the reaction of the water level to the probable 

barrier. Thus, the future pressure buildup cannot be 

forecast until more is learned about the effects of the 

barrier. 

Various rates of injection were tried, ranging from 

380 to 1,400 gpm. Projection of the pressure buildup 

curves indicated that the well would not take as much 

as 1,000 gpm by gravity injection, but that it would 

take mor.e than 380 gpm. The apparent c.oefficient of 

transmissibility of the sandstone in the Yeso formation 

is about 10,000 gpd (gallons per day) per foot. 
SHORT PAPE'RS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293;-4,3·5 D-379 

The results of the injection tests indicate that the 

mill eHluent can be disposed of feasibly by injection 

into the lower pn,rt of the Yeso formation and that 

vertical leakage in significant amounts into the potable 

water aquifers is unlikely. Routine disposal of effluent 

by injection was started in December 1960. 

422. SOME USES OF THE SODIUM-ADSORPTION-RATIO DIAGRAM 

By D. J. CEDERSTROM, Washington, D.C. 

By far the greatest amotmt of ground water used in 

the Tripoli quadrangle, Tripolitania, Libya, is for 

agricttltural purposes. The water used va.ries widely in 

chemical character. As a part of exploration for and 

development of additional ground water supplies in an 

investigation on behalf of the International Cooperation Ad1ninistration, it was necessary to determine the 

agricultural usefulness ·of the water. 

Cla,ssification of water according to a single dissolved 

constituent did not appear to offer a sufficient answer 

nor did specific conductance seein to be more than a 

rough rule-of-thumb guide. The sodium-adsorptionratio (U.S. Salinity Laboratory Staff, 1954, p. 72), by 

itself was only moderately helpful because many highly 

1:ninernJized waters of doubtful value had a fa.vorable 

calcium-sodium ratio. Early consideration, therefore, 

was given to the sodimn-adsorption ratio (SAR) diagram developed by the U.S. Salii1ity Laboratory Staff 

(1954, p. 80) on which total dissolved salts are plotted 

against the sodium-ad~orption ratio . .As might be expected this proved to be an excellent method of classifying irrigation waters. However, when it was applied 

to waters actually used in Tripolitania, several interesting anomalies were observed. 

Effort was made to determine what use might be 

made of waters plotting in the various classes of the 

SAR diagran1. Published tables (U.S. Salinity Laboratory Staff, 1954, p. 67) giving the. relative tolerance 

of various crops were helpful, but did not furnish as 

complete an answer as desired. In the first place, no 

data are given for certain crops such as tobacco and 

peanuts, which are impoi'tant to Tripolitania. Furthe~, 

there seemed to be no way to establish how low "low 

tolerance" (oranges) might be nor how hjgh "high 

tolerance" (alfalfa) rnight be. In addition, a statement 

by l-Imn ( 1959, p. 250) was found to be particularly 

applicable: · · · 

"It is very difficl.llt to predict on the basis of water . 

analyses wliat may ta,ke place in the complex mineral 

assemblage of 1nost soils, where physical adsorption, 

base exchange and the forn1ation of complex salts may 

all occur as irrigation water is added. T4ose who use 

water analyses to evaluate irrigation supplies should 

not depend exclusively upon any classification system 

that takes only the con1position of the water into 

account." 

Accordingly, an "SAR crop diagran1" .(If that designation may be introduced here) was prepared. The 

crop irrigated by a specific water was indicated at the 

point on the SAR diagram where the SAR and salinity 

of the water plotted (fig. 422.1). 

The SAR crop diagram show's at a glance the range 

of usefulness of irrigation waters. As evident on figure. 

422.1, waters having a, medium to high salinity hazard 

can be used successfully to grow oranges if the sodium 

hazard is low. Two reports of oranges grown where the 

irrigation water has a medium sodium hazard are suspect ; these are not grown for commercial use and 

yields may be poor. 

Peanuts and potatoes have a greater tolerance than 

oranges and are raised successfully where sodium 

hazard of irrigation water is high and salinity hazard 

is very high. It may be noted that this class of water 

has two notations, one indicating that these crops can 

be raised successfully,. the other indicating they cannot. Equally or even more interesting is the notation 

for water classified as medium in sodium hazard and 

very high in salinity hazard that neanuts and potatoes 

cannot be raised. Such apparent contradictions emphasize the fact that the chemical character of the water 

may not be the only limiting factor-in this instance, 

the farm where the better water is said to be unsuitable 

for peanuts and potatoes is in a lower rainfall area than 

the farm where the poorer water is used successfully. 

Other factors such as drainage characteristics and 

gypsum content of the soil may influence the usefulness 

of the water. In any event, the diagram suggests that 

in this area some "unsuitable" waters might be used 

for irrigation of low- or medium-tolerance crops by 

proper husbandry. 
D-380 GEOLOGICAL SURVEY RESEARCH 1 9 61 

~ 

0 

..J 

100 2 

A- alfalfa Pe- peanuts 

Be- beans Po- potatoes 

0- oranves T- tomatoes 01- olives Tb- tobacco 

X- unsuitable for irrigation 

of crop shown. 

A Be, 

T' 

0 100 250 750 2250 

Conductivity in micromhosicm (ECxi06)ot25°C 

LOW MEDIUM VERY HIGH 

SALINITY HAZARD 

FIGURE 422.1.-U.S. Salinity Laboratory diagram for f:!lassification of irrigation waters showing crops irrigated by waters 

of various chemical characteristics in the Tripoli area, Libya. 

Alfalfa has an extremely high tolerance-in fact, the 

SAR diagram shown would have to be expanded upward and -to the right to show the complete range of 

tolerance. On the other hand, inspection of the SAR 

crop diagram suggests that at some places valuable 

water on which citrus would flourish is being put to a 

less productive use in raisin.e,: alfalfa. 

The SAR crop diagram affords a convenient means 

of indicating to persons who have little or no acquaintance with chemistry some important aspects of water 

quality and how those aspects are related to agricultural suitability. A series of diagrams, each showing 

where plotted points for analyses pertinent to a particular crop are grouped might be prepared as a visual aid 

in explaining the suitability of any water. Such diagrams also might p~ove useful in public presentations 

of papers dealing with irrigation water. 

The SAR diagram proved helpful in still another 

way not directly pertaining to crop use. An SAR 

diagram of water from a leaky artesian well and of 

shallow ground waters in the immediate area shows at 

a glance the degree of contamination that has occurred. 

In this respect the SAR diagram performs the function 

served by the more elaborate tri-line·ar diagram and is 

more easily understood by the general public. 

REFERENCES 

Hem, J. D., 1959, Study and interpretation of the chemical 

characteristics of natural water: U.S. Geol. Survey Water~ 

Supply Paper 1473, 269 p. 

U.S. Salinity Laboratory Staff, 1954, Diagnosis and improvement of saline antl alkali soils: U.S. Dept. of Agriculture, 

Agriculture Handbook 60. 

EXPLORATION AND MAPPING TECHNIQUES 

423. TECHNIQUES FOR MAPPING OF HYDROCHEMICAL FACIES 

By WILLIAM BAcK, Washington, D.C. 

The concept of hydrochemical facies is a means of 

describing. tl~e ~iagnostic chemical character of water 

solutions in ·aquifers. These facies reflect the effects 

of chemical processes in the lithologic environment and 

the contained ground-water flow patterns. The techniques and procedures used in mapping hydrochemical 

facies were developed during the course of work on the 

Atlantic Coastal Plain as a means of deriving and presenting a coherent generalization from thousands of 

discrete facts. Significant characteristics of hydrochemical facies can be illustrated by methods similar to 

those used in lithofacies studies-trilinear diagrams 

that. show 'the types of facies present in an area or in 

formations, fence diagrams that show the overall facies 

distribution, and maps that show isopleths of chemical 

constituents within certain formations. 

The classification of hydrochemical facies is shown 

in table 1. For simplification of terminology, mag-
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SClENCES, ARTICLES 293~4,3.5 D-381 

nesium and pota.ssium are not mentioned in some of the 

cation-facies terms because of their relatively minor 

importance in the Atlantic Coastal Plain. For other 

areas, these constituents could be added to the terminology. The numerical values (table 423.1) are percentages of the particular constituent indicative of the 

total cations or total anions computed on the basis of 

equivalents per million. The positions ~f these facies 

are shown on the parallelogram diagrams on figure 

423.1. Although two parallelograms are shown here 

for clarification of the nomenclature, analyses commonly are plotted on only one parallelogram, including 

both the ttnions and cations. 

Parallelograms and other similar diagrams are useful primarily for screening and sorting large numbers 

of chemical ·analyses. The percentage of the equivalents per million of the various constituents are plotted 

according to the stratigraphic unit and geographic location. The grouping of the analyses thus plotted may 

be used to identify or group those stratigraphic units 

that contain water of similar chemical character, which 

may be treated as a hydrologic unit. Plotting of the 

analyses provides, further, a basis for determining the 

degree of detail required in delineating hydrologic 

units for the construction of maps and fence diagrams. 

The next phase of hydrochemical facies mapping 

may be the preparation of maps showing the significant 

chemical aspects of the water in selected hydrologic 

units. Unless the study is restricted to one stratigraphic unit, fence diagrams are believed to be one of 

the most effective means of illustrating hydrochemical 

CATION FACIES ANION FACIES 

PERCENT AGE OF CONSTITUENTS 

FIGURE 423.1.-Nomenclature for hydrochemical facies. 

TABLE 423.1.-Classi.fication of hydrochemical facies 

Constituent (percent) 

Ca+Mg Na+K HCOa+COa SOt+CI 

Cation facies: 

Calcium-magnesium_ 90-100 0<10 ---------- -------- Calcium-sodium ____ 50-90 10<50 --------... ·- -------- Sodium-calcium _____ 10-50 50<90 ---------- -------- Sodium ____________ 0-10 90-100 ---------- -------- Anion facies: B~carbonate ________ -------- -------- 90-100 O<lO 

Bicarbonate-chloride-sulfate ________ -------- -------- 50-90 10<50 

Chloride-sulfatebicarbonate. _____ -------- -------- '10-50 50<90 

Chloride-sulfate _____ -------- -------- 0-10 90-100 

facies. They are believed superior to maps for several 

reasons: (a) a large number of maps would be required 

to show the various chemical constituents within the 

several hydrologic units of an area; (b) correlation of 

available data can be done with more confidence on the 

hydrochemical panel diagrams, in much the same manner that geologic block diagrams and cross-sections are 

used to interpret and extrapolate available stratigraphic 

and structural data; (c) the chemical effect of water 

moving across stratigraphic or lithologic boundaries 

can be more readily dep.icted on fence diagrams than 

on maps restricted to one stratigraphic unit. 

A typical fence diagram for part of the northern 

Atlantic Coastal Plain is shown on figure 423.2. The 

fence diagram shows the major stratigraphic or lithologic units in the area and the vertical direction of 

ground-water flow. 

Values for selected chemical constituents are plotted 

on the fence diagra1n according to location and depth. 

The constituents plotted are those most diagnostic of 

the water for the particular area under study: For the 

Atlantic Coastal Plain, which was used as the model 

for this study, the concentration of total dissolved 

solids, bicarbonate ion, chloride ion, and the summary 

fence diagrams showing the cation facies and anion 

facies were judged to be the most informative. However, for some areas the sulfate ion might be more 

significant than the bicarbonate or chloride ions. After 

the values of the particular constituents have been 

plotted, the boundaries between the distinctive facies 

are drawn. Diagrams for minor elements, such as fluoride or iron, can be prepared in the same way. 

In summary, application of the concept of f-acies to 

the che1nical aspects of ground water indicates that the 

nature and concentration of ions in solution are determined by the lithologic character and the ground-water 
D-382 GEOLOGICAL SURVEY RESEARCH 1 9 6 1 

EXPLANATION 

Calcium-magnesium facies Sodium-calcium facies 99.3 

Percent Na + K 

Na+K+Ca+Mg, 

Calcium-sodium facies Sodium facies 

in equivalents per million 

u. 

0 

"' 

0 8 

·~ 

Generalized direction of ground-water flow 

Note: Some wells projected to fence from 

within 2 miles of fence. Not all control is shown 

FIGURE 423.2.-Fence diagram of part of the northern Atlantic Coastal Plain showing hydrochemical facies. 

flow pattern of a particular region (Back, 1960). Development of mapping techniques provides the means 

to present in two dimensions the three-dimensional nature of ground-water flow and the spatial distribution 

of chemical and mineral assemblages. The chemical 

character of ground water within a hydrologic system, 

as depicted in a facies diagram, shows the relation of 

the chemical character of the ground water to the flow 

patterns and to the geologic environment. 

REFERENCE 

Back, William, 1960, Origin of hydrochemical facies of gro~d 

water in the Atlantic Coastal Plain: Internat. Geol. Cong., 

21st, Copenhagen 1960, pt. 1, p. 87-95. 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SClENCES, ARTLCLES 293-4,3,5 D- 383 

424. OPTICAL CURRENT METER 

By WINCHELL SMITH, Menlo Park, Calif. 

Work done in cooperation with the California Department ot Water Resources 

Velocity measurements in open channels are normally 

made with a rotating meter suspended on a rod or sounding line. Infrequently, measurements are made by 

other methods such as timing o:f drift or floats in the 

stream, or use of impact rods which convert kinetic 

energy into a static head. None of these methods is well 

suited to measurement of velocities greater than 20 feet 

per second. In closed conduits, high velocities are routinely measured by Pitot tubes inserted in the stream, by 

timing the rate of transfer of a slug o:f salt solution or 

other material injected under pressure, by computation of dilution of chemicals injected at a known rate, 

or by measurement of energy dissipated when flow rate 

is decreased to zero. Most of these methods could be 

applied to open channel velocity measurement, but in 

each case the instrumentation becomes involved and 

much too complicated :for routine field use. Difficulties 

arise in each case from the necessity :for placing the 

equipment in the stream; this suggests an alternate approach, based on optical principles, which requires no 

physical contact with the flowing water. 

The optical device, described in this paper, gives an 

instantaneous measure of the surface velocity by direct 

observation from a point above the stream. No equipment is inserted into the stream. 

The optical meter, now being developed, is a stroboscopic device whereby the motion of the water surface is 

apparently stopped by adjusting the angular speed of 

a set o:f rotating mirrors. Principal components of the 

meter are shown on figure 424.1. The drive motor is 

powered by a 15-volt battery. 

Velocity measurements are made by looking down at 

the water surface through the meter while gradually 

increasing the angular speed of the rotating mirrors. 

As synchronization is approached, the apparent motion 

of the water surface, seen in the eyepiece as a succession 

o:f images or :frames, gradually slows down until it is 

stopped. If the mirror speed is increased beyond this 

point, the apparent motion is reversed and the water 

appears to move upstream. Angular speed o:f the 

mirror wheel, indicated by the tachometer, and the 

vertical distance :from the meter to the water surface, 

which is measured with a weighted tape, are the measurements needed to compute velocity. The observation 

distance may be varied depending upon the velocity 

regimen and physical features of the site, so long as it 

is measured to the same degree o:f accuracy that is required for the velocity under observation. 

Sensitivity of reading is very precise. The pilot 

model was tested on an irrigation canal near San Jose, 

Calif., where a velocity of 15 feet per second was attained. Consecutive readings made :from a fixed point 

by nine observers checked within 5 percent. None of 

the observers had any previous experience with the 

FIGURE 424.1.-0ptical current meter. 1, telescope; 2 rotating 

mirror; 3, drive motor; 4, tachometer generator; 5, tachometer microammeter; 6, drive-motor rheostat. 
D-384 GEOLOGICAL SURVEY RESEARCH 19 61 

meter; the results therefore indicate that training in 

the use of the instrument is not necessary. 

The small area of the water surface that is seen in a 

given frame· actually travels along the surface on the 

chord of the vertical angle through which it is followed 

(fig. 424.2) . This vertical angle (referred to hereafter 

as the viewing angle) ranged from + 30° to -30° for 

the pilot model.. To synchronize perfectly, the rotational speed of the mirror wheel ·must be mo~ulated 

in proportion to the square of the cosine of the instantaneous angle of view. When the mirror wheel 

is rotated at constant speed, as was the case with the 

pilot model, close synchronization can be obtained only 

I 

I 

I 

I 

A 

I 

I 

I 

I 

Vx 

I 

I 

I 

I 

I 

I 

within the centra.I portion of the viewing angle. Asynchronization of the image at the extremes is believed 

responsible, in large part, for the divergence of the 

readings made by the different observers. 

To correct this difficulty, a second model has been 

built using a set of function gears between the drive 

motor and the mirror wheel. Gearing could not be 

obtained which exactly fitted the required cos2 function, 

so an approximation using eccentrically mounted circular gears was employed. · Preliminary field tests with 

this instrument indicate improvement over the first 

model, but additional calibration work is needed before 

this improvement can be accurately assessed. 

D 

A particle on the moving water surface will remain centered in the field 

of view as it moves from point A to 8 when the angular speed W of 

the mirror is synchronized in proportion to the velocity Vx. Derivation 

of relation is as follows: 

Vx= ___:!!___ = d(D tan 8) D sec..? 8 __!!!!_, __!!!!_ =2W 

~ ~ ~ ~ 

Vx=.?WD sec..?fJ 

As Vx is constant, W must be modulated by cos.?fJ if synchronization is to 

be maintained 

FIGURE 424.2.-Schematic diagram showing relation between 

velocity of stream and rotational speed of the mirror. 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293;-4315 D-385 

425. THE EFFECT OF FINITE BOUNDARIES ON MEASUREMENT OF GOLD-198 WITH A 

SCINTILLATION DETECTOR 

By BERNARD J. FREDERICK and RICHARD G. GoDFREY, Oak Ridge, Tenn., and Washington, D.C . 

. Work done in cooperation with the U.S. Atomic Energy Commission 

Measurement in situ of radioactive tracers in openchannel flow studies appears to have great potential as 

an aid in understanding the micromechanics of flow. 

Ifowever, in the calibration of equipment for absolute 

measurement of . the concentration of activity, the 

boundary conditions of isotope containment must be 

considered. 

Experiments have been made that define the effect 

of boundn .. ry conditions on measurements of isotope 

concentration in cylindrical tanks. In these tests gold198 in the form of A uCla is used as the tracer. A known 

amount of the isotope is added to a known amount of 

water in the tank. The detection system· used has a 

1 in. by 1 in. sodium iodide crystal (thallium activated). 

The crystal, photo-multiplier tube, and transitorized 

pren .. n1plifier are encased in a waterproof plexiglas 

housing. The counting system is a portable batteryoperated decade scaler. The resolving time for the entire syste1n is 50 microseconds. 

In the first test, a tank 4 feet in diameter was filled 

with water to a depth of 5 feet. The isotope was added 

and the mixture was stirred continuously. The probe 

containing the scintillation crystal was suspended at 

164 locations in a vertical plane through the center of 

the tank. The count rate was observed for each location 

and corrected for radioactive decay. Figure 425.1 is 

a scale drawing showing the isograms of the ratio of 

the count rate at various locations to that at the center 

of the tank. The isograms are symmetrical about the 

vertical axis and asymmetrical about a horizontal plane 

at mid-depth. The asymmetry is attributed to a· noncontributing volume containing ·the photo-multiplier 

tube and preamplifier which is located directly behind 

the crystal. Because the probe was suspended with the 

crystal downwards, the ·volume of mixture affecting the 

crystal was less at the bottmn of the tank than near the 

water surface. The isograms (fig. 425.1) indicate that 

the effect of the proximity to boundaries is minor when 

the minimum distance is 12 inches. Thus, the count 

rate in the center of a tank 2 feet in diameter ";ould be 

only slightly less than that in a tank 4 feet in diameter. 

The test was repeated in tanks having diameters of 1 

and 2 feet nnd .filled with a mixture of water and gold-

.198 such thn,t the concentration of the activity was the 

same as in the tank. 4 feet in diameter. figure 425.2 

shows the count rate along the vertical axis of each tank. 

The maximum observed count rate in the 2-foot diameter tank is 75 percent of that in the large tank. As 

in the larger tank, the count rate varies only slightly 

once the crystal is more than a foot away 'from the top 

or bottom. Thus, it appears that tank diameter plays 

a larger role than proximity to the top or bottom. 

To investig~te the depth-diameter effect, water was 

dr~tined out of each tank in successive increments of 4 

inches, and count-rate observations were made with the 

crystal at 2 locations on the vertical axis of the tank-

( a) 4 in. below the water surfa.ce and (b) at the center 

of depth after each increment was removed. The reWATER SURFACE 

~-----0.6 ----~ 

FIGURE 425.1.-Vertical section of a tank 4 feet in diameter 

showing ratio of count rate at vari.ous crystal locations' to 

count rate at center of tank. 
D-386 GEOLOGICAL SURVEY RESEARCH 1 9 61 

UJ 

C) 

~20 

0:: 

:::> 

If) 1-foot 

diameter 

· tank 

2-foot 

diameter 

tank 

?00~--~10~--~2~0----~30~---4~0----~5LO----ro~--~ 

COUNT RATE (THOUSANDS OF COUNTS PER MINUTE) 

4-foot 

diameter 

tank 

FIGURE 425.2.-Relation between count rate and depth of scintillation crystal below water surface. 

suits are plotted on figure 425.3. The graph shows that 

regardless of the tank diameter, the rate of change of 

count rate decreases considerably when the minimum 

vertical distance from the crystal to the nearest boundary is greater than 15 to 20 inches. In the larger diameter tank, the count rate constantly increases with an 

increase in depth, whereas the count rate in the smallest 

tank remains steady for depths greater than about 34 

inches (the crystal being 17 inches from the nearest 

horizontal boundary) . 

In both studies where tanks of different size were 

used, regardless of location of the crystal the rate· of 

increase in count rate was not as great as the. rate of increase in tank diameter. This would indicate that there 

1s a practical "infinite volume," where observed count 

60 

Ul 

UJ 

~50 

z 

~ 

z 

<( 

~ 40~ 0:: 

L&J 

1-

~ 30 

u. 

0 

:r: 

ll: 20 LLJ 

Q 

10 

Ql 

u 

~ 

:; 

Cl) 

~ 

0 

Qj 

,Q 

Cl) 

Ql 

.s:: 

u 

·= v 

1-foot 

diameter 

tank 

.s::. 

c. 

Ql 

'0 

-6 .E 

Ql 

u 

~ :::1 

Cl) 

diameter 

tank 

Ql 

u 

t 

~ 

~ 

0 

Qj 

,Q 

Cl) 

Ql 

.c 

u 

·= o::t 

diameter 

tank 

.s::. 

c. 

Ql 

'0 

-6 .E 

o~----1~o-----2~o----~------4~o-----s~o-----6~0----~ 

COUNT RATE (THOUSANDS OF COUNTS PER MINUTE) 

FIGURE 425.3._:_Relation between count rate and depth of water 

in tank for two positions of the scintillation crystal. 

rate would not change a.ppreciably as volume increases. 

Theoretical considerations indicate that this "infinite 

volume" for a 1 in. by 1 in. cylindrical crystal-would 

be an oblate spheroid whose major axis would be hori- · 

zontal and about 1.3 times as great as the minor axis. 

Extrapolation of the data presented here suggests that 

the major (horizontal) axis might be twice as great as 

the minor (vertical) axis and that these axes might be 

about 70 in. and 35 in., respectively. It is possible, 

however, that the predicted shape of the "infinite 

volume" is considerably influenced by the shape of the 

tank used in the experiments. 

426. THE MAGNIFYING SINGLE-PRISM STEREOSCOPE, VIRTUALLY A NEW FIELD INSTRUMENT 

By T. P. THAYER, Washington, D.C. 

The magnifying single-prism stereoscope is virtually 

a new instrument for stereoscopic viewing of aerial 

photogra,phs in the field. Although designed for and 

by geologists, it should be equally useful for engineers, 

foresters, and others who use aerial photographs outdoors. Basically, the new magnifying model (figs. 

426.1 and 426.2) consists of the single-prism stereoscope 

designed several years ago by W. G. Pierce and J. L. 

Buckmaster of the Geological Survey, with the following additions designed by the author: a magnifying 

system, a traverse bar, and means for holding the photographs in register. The present model when closed is 

13 inches long, 12% inches wide (measured along the 

hinge), and 11j2 inches thick; it weighs 3% pounds. 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293~43 5 D-387 · 

FIGURE 426.1.-Stereoscope open, showing magnifying lenses in 

position for use, traverse bar, and adjustable clips for holding 

photographs. 

Substitution of aluminum for brass in the hinges and 

of plastics or other materials in the small parts would 

reduce the weight by several ounces. The model illustrated was made by the Geological Survey with 

suggestions from J. L. Buckmaster. 

As shown on figure 426.1, the optical system consists 

of two magnifying lenses through which the photographs are viewed, one directly, the other through the 

prism. The vertical support provides for focusing, and 

allows a range in magnification from about 1% to 2 

diameters. The lens mounts are interchangeable for 

FIGURE 426.2.-Stereoscope closed, showing hinge mechanism 

and support by clips at outer corners of covers. 

easy replacement in case of damage, and the lenses themselves can be changed by releasing tension screws on 

the retaining rims. The optical system and traverse bar 

are positioned midway between the covers automatically by the hinge mechanism when the stereoscope is 

opened. All parts of the stereoscopic model may be 

examined by moving the lens system from front to back 

on the traverse bar, and by rotating the lenses to the 

left or right on a pivot through the top of the vertical 

support. The size of the lenses, 1% inches in diameter, 

provides a field 4 to 6 inches across. The low magnifications allow considerable latitude in focusing, while 

providing good definition. The lenses are folded down 

for viewing the model without magnification and when 

the stereoscope is closed for carrying (fig. 426.2). 

The photographs are mounted with the flight line 

normal to the hinge and are held by adjustable-tension 

spring clips that may be rotated to provide clear fields 

in the corners. The clips at the corners away from the 

hinge serve also as stops to protect the optical system 

when the stereoscope is closed (fig. 426.2). The covers 

are of tempered hardboard one-eighth of an inch thick 

and can be replaced easily if broken. 

The principal advantages of the new model stereoscope are : (a) complete coverage of the stereo model 

with a choice of magnification as high as 2 diameters or 

with the prism alone; (b) simplicity of operation; (c) 

easy insertion or adjustment of photographs, but positive retention in stereo position; (d) provision of a 

clear working area and firm support for annotating 

photographs; (e) protection of the photographs when 

not in use; (f) compactness, lightweight, and convenience; (g) suitability for use in the office as a substitute for more expensive stereoscopes. The stereoscope could be adapted for enlargements more than 9 

inches square by substituting a longer traverse bar and 

larger covers. 
GEOLOGICAL SURVEY RESEARCH 19 61 

ANALYTICAL AND PETROGRAPHIC METHODS 

427. TRACE ELEMENT SENSITIVITIES 

By FRANK S. GRIMALDI and ARMIN W. HELz, Washington, D.C. 

There is an urgent need for more and better data on 

the distribution, mode of occurrence, and behavior 

under changing geologic conditions of many elements, 

especially those that are becoming increasingly important in our expanding technology. Inquiry should 

be made into the present status of analytical methods, 

especially to determine whether they are sufficiently 

sensitive to enable detection of the elements in concentrations as· given by their average abundance in the 

crust. 

Compiiations comparing trace-element sensitivities 

of different methods are given by Meinke ( 1955) and 

Winchester ( 1960). Winchester also examined the 

question of analytical sensitivity versus concentration 

of occurrence of an element. The purpose of this report is to bring these data, and some based on pres~nt 

Survey practices, to the attention of the geologist. Such 

data can supply an initial estimate of the lowest measurable concentrations in a sample and may suggest the 

best analytical method. 

The comparative data are much simplified in regard 

to any specific analytical problem. Complexities that 

increase with the number of components of the sample, 

the size and nature of the sample, and the required accuracy must be considered before making the final 

choice of an analytical method. For example, high 

sensitivities are listed for the photometric methods for 

Ba and Sr based on o-cresolphthalein complexone ( table 427.1), but calcium interferes seriously and the separation of these elements from calcium and from one 

another is so complex that the o-cresolphthalein complexone method may be worthless. 

The sensitivities of the elements by "wet," spectrographic, and radioactivation methods are compared in 

table 427.1. Values for the X-ray spectrochemical technique are not included because this method is generally 

not suitable for trace analysis, the detection limits 

ranging from about 5 to 100 micrograms in a 0.1-gram 

sample. However, it should be pointed out that the 

electron probe may have great utility in samples where 

the local concentration of an element is relatively high 

(for example, in a particular mineral phase), yet very 

low when the total sample is GOnsidered. 

"WET" METHODS 

The sensitivities listed in table 427.1 were computed 

from those given by Sandell (1959), Boltz (1958), and 

Gilbert ( 1959) supplemented by those derived from 

original papers and the present authors' experience. 

The limit of detection for the spectrophotometric 

methods is based on a minimum absorbance of 0.01, 

using 1-cm cells and 25-ml volume. There is a reserve 

in sensitivity by at least a factor of 10 if a longer light 

path and smaller volumes are used. The sensitivity of 

the fluorimetric methods is based on obtaining a reading amounting to at least five scale deflections above a 

blank for the limiting amounts shown in a 25-ml volume. The values given for the flame photometric 

methods were obtained by multiplying the limits given 

by Gilbert by a factor of 35. The sensitivities listed 

for "wet" methods are realistic and result in less than 

a 20 percent relative error at the limits of detection. 

SPECTROGRAPHIC METHODS 

D-e arc.-The values shown for the d-e arc are based 

on complete volatilization of a 10-mg· sample in a highcurrent d-e carbon arc. These values are approximate 

detection limits obtained with the d-e arc on mineral 

and rock samples routinely analyzed in the Survey. 

There are too many variables of equipment, type of 

material being analyzed, and spectral region employed 

to consider the values other than approximate. Some 

combinations of elements may be very unfavorable for 

as low a figure as shown for the detection limit while 

in some specific examples improvement may be expected 

if special emphasis is given in the procedure to detecting low concentrations. 

Oopper spark.-The values shown. for the copper 

spark method are from Fred, N achtrieb, and Tomkins 

( 194 7). This method is noted for its high sensitivity 

for a limited kind and size of sample, for example, a 

dilute solution that can be handled by. drying a 

measured drop of a solution on the tip of an electrode. 

These data serve to emphasize the small amount of 

material that can, under favorable conditions, give 

measurable spectra. Although the absolute sensitivity 

is very high, the concentration limits are comparable 
SHORT PAPERS IN THE GEOLOGLC AND HYDROLOGIC SCIENCES, ARTICLEIS 293-435 D-389 

Element 

Approximate 

average 

abundance 

(percent) 

Wet methocls 

Method 1 

TABLE 427.1.-Sensitivities of various methods 

Spectrographic Radioactivatlon 

Minimum Minimum Detection sample D-e arc sample Cu-spark limit to detect detection to detect detection (micro- average limit average limit grams) abundance (micro- abundance (micro-

(grams) grams) (grams) grams) 

Detection Detection Activity limit, limit, Half-life measured flux 100 flux lOU (micro- (micrograms) grams) 

Minimum 

sample 

to detect 

average 

abundance, 

flux1on 

(grams) 

---------1-------·------------1----1----1-----1---- LL. •••••••• 5Xlo-a 

NIL •...•.• 2.5 

K ••.••••••• 2.5 

Rb •.••••••• 2.8Xl0-3 

Cs ••••••••• (1X10-3) 

Bo •••••••.• 4X1o-• 

Mg •••••••• 1.7 

Ca •••.••••• 3.3 

Sr ...•.••••• 3.5X10"2 

Ba •.••••••• 6.4X10"2 

Sc •.••••••.• 1.3X10"3 

Y ---------- 2X1o-a 

La ••••••••• 4X1o-a 

Co ••••••••• (4Xl0"3) 

Pr ••••••••• 7X1Ci' 

Nd ••••••••• ax1o-a 

Sm ••••••••• 4Xlo-• 

Eu ••••••••• (to-•) 

Od •.•.••••. (7XIO"') 

Tb......... (JO-•) 

Dy......... (4X10"4) 

Ho ••••••••• (10"4?) 

Er ••••••••• (2X10"4) 

Tm •••.•••• (1X1Q-4) 

Yb......... (2X1Q-4) 

Lu......... (1X1Q-4) 

Tl. ••••••••• 4X10"' 

Zr •••••••••• 2X1Q-2 

Hr.. ••••••• 3Xto-4 

Th ••••••••• 1Xto-a 

V ---·------ 1X1Q-2 

Nb ••••••••• 2X1Q-3 

Ta ••••••..• 2X10"4 

Cr ••••••.•• 1X1Q-3 

Mo.· ••••.•. 2X1Q-4 

w _________ (to-•?) 

u .......... 3Xto-4 

Mn ••..•.•. 0.1 

Ro ••••.•.•• (1Q-7?) 

Fo ••••.•••• 4.7 

Ru......... (lQ-B?) 

Os... •• . . . • (lQ-B?) 

Co •••••..•. 2Xto-a 

Rh .••.••••. (10"7'?) 

Ir.......... (10"7'?) 

Nl.. ••••••• IXI0"2 

Pd •••••.•.• 2XIQ-O 

Flame photometry •.•.•.•... _ .•. _._. 

Thoron (S) ----------•.•. _____ ... ___ _ 

Flame photometry •. _._ .•. _ .•. _._._. •.•.• do ______________________________ _ 

.•••• do _____________________________ _ 

••••• do _____________________________ _ 

Morin (F>-----------------·-------- Oxine butylamine (S) ______________ _ 

Flame photometry •.•.•.•.•. _ ••.•..• 

Murexide (S>-----------------------

Flamo photomotrY------------------

o-crcsolphthalcin complcxone (S) ..•. 

Flame photomotrY------------------

o-crcsolphthaloln complcxone (8) •••• 

Ox inc (S) •• ------------------------- Morin (F) _________________________ _ 

Alizarin red 8 (8)-------------------

-•••• do •.••.••••••.•...•....•...•..•. 

As Ce(804)2 (8) .. ------------·------

Allzarln rod 8 (8)-------------------

-----do ••.••.••.•.•••. _______________ _ 

••••• do •.. ----------------------- ___ _ 

••••• do •• ----------------------------

--- •• do •••••••••.••. ---•.• ___ ------·-

--••• do •••••..•... ------.. " .•••.•...• 

..... do ••••.. ----.• ---•••••••••• __ .•• 

--- •• do._--------------------- __ ...•. 

•••.• do •• ------------------. ________ _ 

•••.• do._-----------.----------------

-•.•• do •. _ •.•.•.. __ ••.• ____ ...•.. _ ... 

••••• do ••.•.•.•.•.•••. _ ••. __ . __ . __ • __ 

Tiron (8). --------------------------

Morin (F).--------·----------------

Quercetin (8) •• ___ --------- ________ _ 

Morin (F).-----------·-------- ____ _ 

Quercetin (8) •• --------------------- Thoron (8) ••.•••••.•••••.••. ______ .• 

Phosphotungstic acid (8) ••. __ ..... . 

Thiocyanate (8) •. ------------------

Pyrogallol (8) ---------- ____________ _ 

Phenylftuorono (8) _________________ _ 

Diphonylcarbazide (8) ••...... ~----­

As chromate (8) •• ------------------

Thiocyanate (8). -·------------------

Dlthlol (8) ••• -----------------------

Thlocyanato (8) •.•• --------- ______ _ 

Dlthlol (8) ••. _____ ------- ________ ••. 

NaF (F>----------------------------

Thlocyanato (8) •• ------------------

As Mno,- (8>-----------------------

4, 4'Totramothyldlamlnotrlphenyl 

Methane (8). 

Catalysis To 8nCl2 (8) _____________ _ 

Thiocyanate (8) •• ------------------ o·phenanthrollne (8) _______________ _ 

Catalysts Co (IV), As(III) (8) .. _ •.. 

o·phcnanthroline (8) ----------------

Catalysis Ce(IV), As (III) (8) __ ----

Totraphcnylarsonlum chloride (8) __ _ 

Nltroso·R salt (8)-------------------

2-nltroso-1-naphthol (8). ___________ _ 

8nCI2 (8) .• --------------------.----

2 mcrcapto-4, 5 dimethyl thlazolo (8). 

8nCI2-HBr (8)----------------------

Dimcthylglyoxlme+oxldant (8) •.... 

a·furlldloxlmc (8) -------------------

p-nltrosodlphenylaminP (8). --------

0.5 

. 25 

.15 

8 

25 

85 

. 001 

. 75 

9 

.8 

250 

2 

(15) 

0.01 

.005 

6X10"8 

3X1o-• 

.09 

(8. 5) 

2.5xto-• 

6X1Q-& 

7Xlo-& 

2X10"6 

1 

.03 

.003 

.4 

. 002 

.2 

2. 5 

5 

.15 

.15 

5 .. 15 

.7 

. 15 

1 

(5) 

. 7 

5 (5) 

5 (1) 

(5) 

(2. 5) 

(5) 

(2. 5) 

(5) 

2.5x1o-4 

. 2 1X1o-a 

. 6 4.5X1Q-I 

. 4 .13 

1. 2 .6 

5 .5 

.05 

.05 

10 5 

.8 .4 

. 3 3X1o-a 

3 .03 

2. 5 1. 2 

1.2 .6 

2.5 2.5 

2. 2 2.2 

. 001 3X10"4 

17 6 

7 7X1o-a 

. 025 2.5X1Q-5 

.001 

1. 3 1300 

1.3 3X10"6 

0. 001 (10?) 

1. 3 1.3X10t 

. 01 (100) 

5X10' 

. 5 . 025 

1.0 .05 

6. 5 (6.5X1Q3) 

1. 7 (1.7X1Q3) 

(1X103) 

.01 

1.3 70 

. 3 15 

0. 007 2X10"4 

1 

2 

.03 

.3 

.1 

.3. 

.01 

.01 

lXl~ 

1Xlo-& 

4X10"4 

.03 

2.5Xto-a 

6X1Q-B 

. 01 3Xlo-7 

. 01 3Xlo-& 

. 01 lXlO"& 

. 01 

.05 

.2 

.5 

.5 

.2 

. 3 

. 5 

. 3 

.2 

.2 

.2 

. 01 

.2 

.02 

1X10"3 

2.5Xto-a 

5Xto-a 

.025 

.3 

.02 

. 1 

.2 

.04 

.. 5 

. 08 

.2 

.1 

.2 

5X1Q-a 

.2 

5Xlo-& 

. 05 2.5Xto-• 

.3 

2 

.02 

.05 

.1 

.2 

2X1o-• 

2.5X1Q-3 

. 5 

.02 2X1o-• 

.02 .01 

.5 .5 

4 1.3 

0. 0002 

.01 

.01 

.02 

. 05 

.0002 

.001 

. 01 

.05 

. 0005 

.001 

.. 005 

.05 

.02 

.02 

.02 

.002 

.01 

. 05 

.. 02 

.05 

.005 

. 01 

.2 

. 01 

.01 

.05 

.02 

.005 

.02 

.1 

.005 

. 005 

.05 

.1 

14.8h Nau 

12.4b K43 

17.8m RbBB 

3. 2b csmm 

10.2m Mg37 

8.8m can 

2.8h 8r86m 

85m 

85d 

62h 

40h 

33h 

19h 

1. 7h 

47h 

9.2b 

18b 

7ld 

2. 4b 

27h 

7.5h 

127d 

~b 

3. 7h 

6m 

17b 

BalBO 

8c•o 

yoo 

LaHo 

Cetca 

PrU2 

NdUO 

8ml63 

Eut&2 

GdUO 

TbiOO 

Dyte& 

Hotoe 

Erl71 

Tmt7o 

Ybt77 

Lu176m 

Ttn 

46d Hft81 

22m Thna 

3.7m V&2 

6.6m Nb04m 

16m TAIUm 

3.5m CrM 

14.6m Motot 

24h Wt87 

24m 

16 

190 

48 

700 

80 

300 

48 

16 

100 

110 

15 

1X1Q3 

6 

55 

2. 3 

. 05 

60 

300 

.15 

1.6 

30 

100 

16 

.6 

110 

5X103 

0. 016 6X1Q-' 

.19 7.5Xl~ 

.05 2Xto-• 

. 7 .07 

. 08 5X1Q-6 

.3 lXlQ-5 

. 048 1.4X1Q-' 

. 016 3X1Q-& 

.1 

.1 

.02 

1 

.006 

.06 

.002 

5X10"6 

.06 

.3 

1.5XIO-& 

.002 

.03 

.1 

.016 

6X1o-• 

.1 

5 

8X1o-a 

5X1G-3 

sx1o-• 

. 025 

1X1o-a 

2Xto-a 

5Xto-• 

5XIQ-& 

. 01 

.3 

4XIQ-6 

2X1Q-3 

.015 

.1 

8Xto-a 

6X1Q-4 

2.5X1Q-& 

.025 

1.4X103 1. 4 .5 

6XlO"& 

2.6X1Q-O 

5XlQ-& 

. 6 6X1Q-' 

. 26 . 2.6X1Q-' 

1. 3 1X10-a 

100 .1 .05 

100 .1 1X1Q-B 

36 .036 .018 

10 .01 . 01 

.002 1X1Q-3 . . ·--·------ ----------- ---------- ---------- ............................. ---------- ----------- ·---------- . 01 1X1Q-& 

.2 

.1 

. 2 

.4 

200 

2X1Q-6 

2Xlo-a 

4X1Q3 

. 01 5X1Q-4 

.03 30 

.5 500 

. 02 2X1o-• 

.02 

.002 

.2 

.05 

. 05 

.5 

. 01 

.05 

2.6b Mn&e 

17h 

46d 

ReiSS 

Fe 5o 

4.5h Ruto& 

32b Osto3 

10. 7m Cosom 

4.4m Rh104m 

19h Ir104 

2.5b NiB& 

13h 

. 32 3.2X1o-• 3XIQ-7 

1.8 

1.6XIOS 

110 

180 

1.8XIO-a 

1.6X103 

0.1 

. 2 

1. 8 

.03 

1Xtoa 

2X103 

1. 4 1.4X1Q-B 7XlQ-& 

.15 1.5X104 

1.1 1X1Q-3 

190 . 2 

11 . 01 

.15 

1 

2X1o-a 
D-390 GEOLOGICAL SURVEY RESEARCH 1 9 6 1 

TABLE 427.1.-Sensitivities of various methods-Continued 

Wet methods Spectrographic Radioacti vation 

Approximate 

average 

abundance 

(percent) 

Minimum Minimum Minimum 

sample 

to detect 

average 

abundance, 

flux 1012 (grams) 

Element Detection sample D-e arc sample Cu-spark Detection Detection limit. to detect detection to detect detection Activity limit, limit, Method 1 (micro- average limit average limit Half-life measured flux 109 flux 1012 grams) abundance (micro- abundance (micro- (micro- (micro-

(grams) grams) (grams) grams) grams) grams) 

----·1----1-------------1----1-----1---------------------1-----1-----

pt__________ (5X10-7) SnCh (S) ------ _ --------------------- 6 

p-nitrosodimetbylanlline (S) _______ _ .8 

(1X103) 

130 0.05 10 0.002 31m Ptl99 16 0.016 3 

Cu_________ 7X10-3 Dithizone (S) --------------------- _ .6 . 01 ---------- ----------- ---------- ---------- ---------- ---------- ----------- -----------

Ag _________ 2X10-> 

Au_________ (10-7) 

zn_ _ _______ 8X10-3 

Cd_________ 1X1o-s 

Hg_________ 6X10-6 B __________ 1X10-3 

AL________ 8.1 

Ga_________ 2.6X10-3 

In__________ (10-5) 

TL________ 1.7XIO-• 

29.1 

2-2'Biquinol!ne (S) _________________ _ 

p-diethylaminobenzylidener hodanine (S). 

Rhodamine B (S) __________________ _ 

p-dlethylaminobenzylidenerhodanine (S). Dithizone (S) ___ -- _________________ _ 

Zincon (S) ___ -----------------------

Dithizone (S)_ ---------------------- - ____ do ____________ --- _______________ _ 

1-1'Dianthrimide(S) ________________ _ 

Alizarin S-Ca (S) ___________________ _ 

Oxine (F) _____ ------------------ ___ _ 

Rhodamine B (F) __________________ _ Oxine (F) __________________________ _ 

Dithizone (S) _ ----------------------

Oxine (For S>-----------·------------

Ditbizone (S) _ ---------------------- Rhodamine B (S) __________________ _ 

Ammonium molybdate-reductant 

(S). 

2. 5 

1.3 

.6 

1.2 

.2 

.25 

1.1 

.15 

.5 

.15 

.1 

.1 

.5 

2. 5 

.6 

.35 

.04 

6 

600 

1.2X103 

2.5X1o-a 

. 012 

2. 5 

20 

. 015 

5X10-tl 

2X10-6 

4X10-• 

4XIO-• 

5 

50 

1.5 

.35 

1X10-6 

. 003 4X1o-s 

. 001 5XI0-3 

. 1 

.8 

.2 

.2 

.2 

.1 

100 

. 01 

2 

3 

.02 

1X10-6 

. 03 1X10-3 

.05 .5 

. 2 .12 

.05 2X10-7 

.02 

.2 

.2 

.5 

0.01 

.1 

. 1 

.01 

5m Cu66 

2.3m Ag1os 

2. 7d AulDS 

57m 

3b 

43m 

Zn69 

Cd117m 

Hgl99 

2.4m AJ28 

21m Qa7o 

54m In 116m 

4.2m Tl206 

2.8h Si31 

1.7 

. 1 

3.2 

128 

83 

.8 

2. 5 

1.4 

. 002 axw-s 

1XIO-• 5X10-• 

3X10-3 3 

.1 1X10-3 

.08 .8 

8XIO-• . o1a 

2.5XI0-3 3X1o-s 

1.4X10-3 5X1o-s 

.027 ·2.7XI0-5 2.7X10-• 

44 

630 

.04 .024 

. 6 2X10-6 

Ge _________ 2X10-• Phenylfluorone (S) _________________ _ . 21 .11 ---------- ----------- ---------- ---------- ---------- ---------- ----------- -----------

Sn ___ ------ 3.2X10-3 

Pb_________ 1.6X10-3 

N__________ (?) 

P __ -------- 9X10-2 

As _________ 2X10-• 

Sb ___ ------ 3XI0-5 

BL________ (10-5) 

S___________ 9X10-2 

Se__________ (I0-6?) 

Te__________ (10-7?) 

F ---------- 6.6X10-2 

CL________ 2.3X10-2 

Br_~------- 1.8XIO-• 

L--~------- 4X10-s 

Molybdate-reductant (S) ___________ _ 

Dithiol (S) ----------- _ ---------- ___ _ Phenylfluorone (S) _________________ _ 

Dithizone (S) __ ---------------------

Nitrate N-phenyldisulfonic acid (S)_ 

Ammonia N-Nessler's reagent (S) __ _ 

Molybdate-reducing agent (S) ______ _ _____ do ______________________________ _ 

Rhodamine B (S) __________________ _ 

Dithizone (S) __ ---------------------

Formation of methylene blue (S) ___ _ 

Reduction to metal-colorimetry ____ _ 

3, 3'diaminobenzidine (S) ___________ _ 

As iodotellurite (S) _________________ _ 

Zr-eriocbromcyanine-R (S) _________ _ 

Thoron-Th (S) _____________________ _ 

o-tolidinc oxidation (S) _____________ _ 

Nephelometrically as AgCL _______ _ 

Rosaniline (S) -----------------------

Catalysis of Ce(IV)-As(III) reaction 

(S). 

Starch-iodine (S) _____________ ----- __ 

I (S), spectrophotometr~; (F), fluorimetry. 

2 

12.5 

5 

.8 

.4 

1 to 5. 

.3 

.45 

. 75 

. 75 

.25 

3 

.35 

.5 

10 

.3 

1 

.005 

.5 

1.0 

.4 

.16 

.05 

axw-• 

.23 

2. 5 

(7. 5) 

10-3 

300? 

200? 

(350?) 

7.5X10-• 

.015 

1.3X10-3 

.02 

.6 

.013 

1.2 

with the d-e arc (which can use a much larger sample) 

if it is assumed that the copper spa.rk sample size is 

limited to no more than 250 micrograms. In general, 

the copper spark is applied to 50 micrograms or less in 

which one element predominates. The method holds 

promise for the analysis of small samples, especially if 

pre-enriched, or for natural materials such as liquid 

inclusions. 

ACTIVATION METHODS 

Data, for activation analysis were largely taken from 

a blll1etin by Burrill and Gale (1960) available from 

3 

.05 . 025 ---------- 89m Gels 

. 04 1.3XI0-3 ----------

.05 3X10-3 . 005 

.04 

1.5 

3.3 

.4 

.5 

.5 

.02 

5X103 .05 

9.5m Snl25 

3.3h Pb209 

14.3d p32 

27h . As76 

2.8d Sbl22 

5d Bi2IO 

5m S37 

18m 

25m 

SeBI 

Tela I 

22 

59 

7.7X10• 

1X103 

11 

50 

4X10• 

2.7X10f 

6 

36 

.02 .01 

. 06 2X10-3 

77 4.8 

1X10-• 

.01 5X10-3 

.05 .2 

40 . 400 

27 3XI0-2 

6XI0-3 

.036 36 

3X10-3 . 01 ---------- ---------- ---------- ----------- -----------

37. 5m Cl3B 

18m Brso 

25m 1128 

6.2 

1 

.4 

6XI0-3 

1X10-3 

4X10-4 

axw-s 

5.6X10-• 

1X10-3 

the High Voltage Engineeril'tg Corporation. The detection limits are based on a counting-rate of 1 disintegration per second above background, assuming a 

10-percent. counting efficiency; the bombarding period 

is 1 hour, with thermal fluxes of 10° and 1012 n/sec-cm2

• 

It is immediately apparent that for fluxes of the order 

of 109 ,. activation analysis is not competitive with wet 

chemical methods. The method, however, shows 

promise for determining some of the rare-earth elements. 'Vith the higher fluxes available from reactors, 

activation analysis represents the ultimate in sm1sitivity. 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293~43·5 D-391 

CONCLUSIONS 

Using sensitivity as the only criterion, it can be seen 

Umt wet methods can be used to detect many elements 

in concentrations represented by their average almndance as given by Vinogrndov ( 1956) based on 2 parts 

of "average acidic rock" and 1 part of "average basic 

rock." If it is assumed that the sn,mple size suitable 

for wet chemical met.lwds-is limited to several grams, 

the following elements cannot readily be determined by 

wet chemical methods: Ru, Os, Rh, Ir, Pel, Pt, Ag, Au, 

lig, Cs, most of the rare earth elements, In, Se, and Te. 

vVithout pre-enrichment, the d-e arc method fails for. 

the following elements based on a 10-mg sample: Hf, 

l'h, Ta, "r, V, He, Hu, Os, Rh, Ir, Pel, Pt, Au, Ccl, Hg, 

B, Cs, most of the rare earth metals, In, Tl, Ge, As, Sb, 

Bi, Se, Te, and F. Assuming a 0.5-g sample and a flux 

of 1012 n/sec-Cln2, the radioactiva.tion method fails for 

the fol1owing elements: He, Hu, Os, Ir, Pt, Au, Ccl, Pb, 

B.i, Se, ~tnd Te. 

REFERENCES 

Boltz, D. F., 1958, Colorimetric determination of nonmetals: 

New York, Interscience Publishers, 372 p. 

Bm·rill, E. A., and Gale, A .. J., 1960, Activation analysis with 

Vande Graff neutron sources: Burlington, Mass., High Voltage Engineering Corp., Bull. AA, 12 p. 

Fred, l\L, Nachtrieb, N. H., and Tomkins, 1!,. S., 1947, Spectrochemical analysis by the copper spark method : Optical 

Soc. America .Jour., v. 37, p. 279. 

Gilbert, Paul T., Jr., 1959, Flame spectra of the elements: l!'ullei·-

ton, Calif., Beckman Instruments Div., Bull. 753, 35 p. 

Meinke, ,V, ,V,, 1955, Trace element sensitivity, Comparison of 

actinltion analysis with other methods: Science, v. 121, 

p. 177-184. 

Sandell, E. B., 1959, Colorimetric determination of traces of 

metals, 3d ed.: New York, Interscience Publishers, 1032 p. 

Vinogradov, A. P., 1956, The regularity of distribution of chemical elements in the earth's crust: Geokhimiya, p. 1-52. 

·winchester, J. ,V., 1960, Radioactivation analysis in inorganic 

geochemistry, in Cotton, F. A., ed., Progress in inorganic 

chemistry, v. 2 :New York, Interscience Publishers, p. 1-32. 

428. USE OF RELEASING AGENTS IN THE FLAME PHOTOMETRIC DETERMINATION OF M~GNESIUM 

AND BARIUM 

By JosEPH I. DINNIN, 'Vashington, D.C. 

The flame spectra of magnesium and barium, like 

those of calcium and strontium, are seriously affected 

by the presence of aluminum and numerous other elements in the solution aspirated into the flame. Because 

the elimination of the interference's usually necessitates 

a time-consuming separation, not always completely 

successful, t.he usefulness of the flltme photometric of 

these elements is seriously impaired. · 

Silica, phosphate, and sulfate are among the most 

serious depressants of the magnesium emission (Dean, 

1960); sulfate and phosphate can redhce the weak flame 

emission of barium by approximately half of its original value. Releasing agents eliminate depressive interferences in the determination of calcium and strontium 

(Dinnin, 1960; Art. 429). The presm.1t investigation 

shows that the releasing effect also applies in the determination of magnesium. and barium. 

The methods, reagents, and instruments used in this 

study were the same as those described earlier (Dinnin, 

1960). The resonance line a.t 285.2 m,u was the primary 

wavelength used for the study of magnesium; background was measured at 286.0 m,u. Supplementary data 

were obtained at 'the band heads 371 m,u and 380 m,u 

with backgi·ound corrections made at 376 m,u and 420 

m,u, respectively. The band head at 488 m,u and. the 

resonance line at 553.6 m,u were used for the study of 

barium; background 1neasurements were made at 470 

mp. ancl560 m,u, respectively. 

Acetone, like many other organic solvents, enhances 

the spectral emission of magnesium and ba.rium many 

fold. Although studies with organic solvents have been 

made with magnesium, they have not as yet been made 

with barium. The results presented here for the effect 

of releasing agents on magnesium include studies made 

in perchloric acid and 80 percent. acetone media. 

MAGNESIUM 

PERCHLORIC ACID MEDIA 

The depressive effects of aluminum a.nd phosphate 

were found to be less severe at 285.2 m,u tha .. n a .. t 371 m,u 

and 383 m,u. At 285.2 m,u, 100 ppm (parts pei~'million) 

aluminum depresses the emission of 30 ppm magnesium 

approximately 20 percent; a.t :371 m,u and 383 mf.t, the 

magnesium is depressed more tha.n 40 percent. Phosphate (100 ppm), at 285 m,u reduces the magnesium 

emission 35 percent; at 371 m,u and 383 m,u the magnesium emission is reduced more than 60 percent. The 

explanation for this differential depressant effect is 
D-392 GEOLOGICAL SURVEY RESEARCH 19 61 

probably based on the fact that emission at 285.2 m,u is 

due to the resonance of the neutral atom and those at 

371 m,u and 383 m,u are thought to be due to the MgOH 

molecule. 

At 285.2 m,u, calcium, strontium, or barium in concentrations greater than 500 ppm releases the full emission 

of 30 ppm magnesium from the depressive e·ffect of 100 

ppm phosphate. Each of the three ele1nents, in their 

effective concentrations, contributes a lower background 

emission than the emission of 30 ppm magnesium. 

At 371 m,u and 383 m,u, the background contributions 

of strontium and barium are too high to warrant 

further study. However, calcium at these \Ya velengths 

contributes a lower background emission than magnesium and releases magnesium from the depressive 

effects of 100 ppm phosphate. The reagents act similarly in the presence of 100 ppm aluminum. 

EIGHTY PERCENT ACETONE MEDIA 

In addition to enhancing the flame emissions of many 

elements, acetone and many other organic solvents are 

known to eliminate partia1ly or completely the depressant effects of many anions. This was verified when it 

.was found that the depressive effects of both aluminum 

and phosphate on magnesium in 80 percent acetone is 

less than half of their effect in 2 percent perchloric acid. 

Both calcium (200 ppm) and strontium (800 ppm) in 

80 percent acetone release the full emission of magnesium from the depressive effects of either 100 ppm aluminmn or phosphate, while contributing less 

background em.ission than magnesium. High concentrations of ba,rium precipitate with phosphate and barium can not be studied in high concentrations; however, 

barium does not precipitate in 60 percent acetone and 

can be used in this medium. 

Lanthanum and many rare-earth elements give a low 

background emission in the lower wavelength region 

and their use as releasing agents should be attractive. 

Lanthanum has been used in this laboratory for the determination of magnesium in chromite; it effectively 

releases magnesium from the depressive effect of relatively high concentrations of aluminum. 

BARIUM 

The use of releasing agents for the elmination of interferences in the determination of barium has been 

studied less extensively. However, data thus far obtained indicate that releasing agents are also effective 

with this eletnent. Strontium ( 800 ppm) and ·calcium 

( 500 pptn) completely release the emission of 20 ppm 

barium from the depressive effect of 100 ppm aluminmn 

or phosphate. However, both strontium and calcium, 

in their effective concentrations, contribute a higher 

background emission than the net emission of barium. 

Magnesium, although contributing a lower background 

emission than barium, releases a maximum of 85 to 90 

percent of the full emission of barium in the presence of 

100 ppm aluminum or phosphate. 

REFERENCES 

Dean, J. A., 1960, Flame photometry: Xew York, ~lcGraw-Hill 

Book Co., 354 p. 

Dinnin, .J. I., 1960, Releasing effects in flame photometry ; determination of cal<.:ium: Anal. Chemistry, v. 32, 1). 1475-1480. 

429. FLAME PHOTOMETRIC DETERMINATION OF STRONTIUM WITH THE USE OF RELEASING AGENTS 

By JosEPH I. DINNIN, Washington, D.C. 

The flame photometric determination of strontium is 

seriously affected by several depressive interferences. 

Although the presence of calcium no longer presents a 

problem, as it does in classical gravimetric analysis, 

difficulty does arise from the presence of silicates, 

aluminum, phosphate, and sulfate, all of which are 

commonly associated with strontium. These elements 

and compounds, along with less commonly associated 

boron, beryllium, chromium, iron, manganese, tungsten, 

and zirconium, seriously depress the flame emission of 

strontium. Silica, in high concentration, luts been reported to depress 99 pe.rcent of the emission. 

It has been known for some time that high concentrations of calcium salts would eliminate the depressive 

effects of aluminum. It is only recently, however, that 

the nature of the depressive effects has been elucidated 

and that general means have been found for the elimination of other depressive interferences. 

Dean (1960) has reviewed the general flame photometric determination of strontium and Dinnin (1960) 

has reviewed the use of releasing agents to eliminate the effects of depressive interferences. It was the 

purpose of the present investigation to determine 

whether releasing agents could be applied to eliminate 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293~43,5 D-393 

depressive intereferences in the flame photometric 

determination of strontium. 

The methods, reagents, and instruments used in this 

investigation were the same as those described earlier 

(Dinnin, 1960). Studies were made at 2 wavelength 

cornbinations: the resonance line at 460.7 mp. ( millirnicrons) was used with background measurements at 

454 und 466 mp.; the band head at 683 mp. was used with 

bnckground measurements at 695 mp.. 

Calcium has been the releasing agent most frequently 

used for the elimination of interferences in the determination of strontium. liowever, as n1ost commercial 

salts of calcium contain appreciable a.mounts of 

strontium it: is critical that corrections be made for the 

strontium impurity, especially in the determination of 

low strontium concentrations. Also, with high concentrations of calcium it may be impossible to correct 

completely for the continuous radiation exhibited bv 

ealeium. · 

The effect of increasing concentrations of calcium, 

magi1esium, barium, and praseodymium on the flame 

emission of strontium in the presence of 100 ppm (parts 

pet· million) aluminum is shown on figure 429.1. Alt'lwugh corTected for background emission and strontium impurity, calcium appears to enhance the emission 

of strontium. This is in part due to the continuous 

emission of calcium which is not completely corrected 

by background measurements. Magnesium and barium 

do not completely release strontium from the depressive 

effect of aluminum. ·Their releasing action approaches 

a maximum of approximately 70 percent and decreases 

with increasing concentration. Praseodymium, in the 

concentrations indicated, completely releases strontium 

from the depressing effects of aluminum. 

Lanthanum and neodymium give results similar to 

those shown for praseodymium. All three elements release 20 ppm strontium from the depressing effects of 

100 ppm aluminum, phosphate, or sulfate. Although 

the background emissions of lanthanum, praseodymium, and neodymium at 681 and 695 mp. are too intense or unequal to be useful, their backgrounds at 

461 mJ.t are low and uniform on each side of the 

strontium line. 

Praseodymium and neodymium ·are· the only rare 

earth elements studied thus far for use as releasin o- o 

agents for strontium. Other rare earths may also be 

useful for this purpose. Pure oxides are now commercially available and their use is no longer economically 

prohibitive. 

Praseodymium has been most frequently used as releasing agent in this laboratory. It has been used for 

the determination of strontium in silicate and phosphate rocks and in a wide assortment of minerals. 

604493 0-61-26 

_ no 1-

EXPLANATION 

6 Calcium: 461 mp.; 0.03mm slit 

z 

"" li 100 0 

Magnesium: 461 mp.; 0.05mm slit "" ll. 

0 

Barium: 671 mp.; 0.20mm slit 

X 

Pr~seodymium: 671 mp.; 0.05mm slit 

8 9 10 

MILLILITER OF 1 MOLAR SOLUTION PER 50 MILLILITERS 

FIGURE 429.1.-Effect of calcium, magnesium, barium, and 

praseodymium on the flame emission of strontium in the 

presence of aluminum. Strontium concentration, 20 ppm; 

aluminum, 100 ppm; perchlorie acid, 5 11ercent. 

As most rocks and minerals are decomposed by a 

procedure which inclw:les the use of hydrofluoric -acid, 

no interference is normally encountered from the presence in solution of high concentrations of silica. However, in the direct analysis of natural water, the presence of silica would be of concern. If strontium is to 

be determined in natural water, it is advisable that 

silica be volatilized by evaporation with hydrofluoric 

acid prior to ·analysis. 

In rocks and minerals, strontium is usually determined in an aliquot of a solution prepared for .the determination of several elements. The preparation of this 

solution has been described elsewhere (Dinnin, 1960). 

~efore takin.P an a~iquot for the determination of strontium, an estimate IS made of the amount of releasing 

agent required to provide a mole ratio of releasing 

agent to depressant of approximately 25 to 1. This 

ratio has been determined empirically and varies with 

the concentration of strontium and the nature of the 

materials being analyzed. The ratio, 25 to 1, is a maximum that luts normally been required in the analysis 

of many types of materials;. a lower ratio suffices for 

the determination of extremely low concentrations of 

strontium. The following procedure is normally used 

for the flame photometric determination: 

Take an aliquot such that the final solution 

aspirated into the flame conbtins a maximum of 

10-20 ppm strontium. Add the required amount of 

releasing agent to the sample and standard solutions and add additional perchloric acid as required to form a 5-percent solution ( v /v). Dilute 
D-394 GEOLOGICAL SURVEY RESEARCH 19 61 

samples and standards with water to the same 

specified volume. Aspirate the solutions into the 

flame. 

Measure the gross emission at 461 m,u and the 

background emissions at 454 and 466 m,u. Subtract the average background from the gross emission. Compare the net emissions of the samples to 

the net emissions of the standards by interpolation 

or by plotting a standard curve. 

The concentrations of depressants in a given rock or 

mineral species are usually of the same order of magnitude and the estimated amount of releasing agent is 

normally sufficient to counteract the effects of the range 

of interferences normally encountered. In carbonate 

rocks, the high concentrations of calcium or magnesium 

are normally sufficient to eliminate the depressive effects 

of aluminum or other depressants present. Additional 

reagent may have to be added to phosphate rocks to 

overcome the high concentrations of phosphate. 

REFERENCES 

Dean, J. A., 1960, Flame photometry: New York, McGraw-Hill 

Book Co., 354 p. 

Dinnin, J. 1., 1960, Releasing effects in flame photometry; determination of calcium: Anal. Chemistry, v. 32, p. 1475-1480. 

430. CHEMICAL AID FOR DISTINGUISHING CHROMITE, ILMENITE, AND MAGNETITE 

By J osE·PH I. DINNIN and E. G. WILLIAMS, 'Vashington, D.C. 

Chromite, ilmenite, and magnetite frequently occur 

in heavy mineral fractions of' ultramafic rocks and 

laterites. Except for the magnetic properties of magnetite, all three minerals have similar physical properties, and they may be difficult to distinguish. All three 

have a metallic luster, hardness of 6, specific gravity 

. greater than 4.5, and are usually black. The following 

chemical technique has been found to be useful as an 

aid in distinguishing them : 

Reagent: Mix equal volumes of concentrated phosphoric 

and sulfuric acids. 

Procedure: Add approximately 10 mg of the finely pulverized mineral to a beaker containing 10 ml of reagent. Swirl to disperse completely. Hea.t gradually 

until the mineral is completely disintegrated or dissolved. Cool. Dilute with water to approximately 

40 ml. 

Characteristic reactions of each of the three minerals 

in both the concentrated and diluted solutions are 

listed below. Portions of the diluted solution can be 

used for more specific tests for characteristic elements 

1n the minerals. 

Mineral 

Rate of dissolu- Color of concen- tion trated solution Color of diluted solution 

Chromite ___ Slow ____ .. _ .Emerald Emerald green 

green 

Ilmenite ____ Rapid _____ Murky Colorless (white 

white precipitate) 

Magnetite __ Very rapid_ Pale green_ Pale green 

431. COMPLETENESS OF PRECIPITATION OF SELENIUM AS THE ELEMENT 

By IRviNG MAY and FRANK CuTTITTA, 'Vashington, D.C. 

As part of a more comprehensive study of analytical 

methods for determining seleni urn, tests were made o:f 

the completeness of precipitation of elemental selenium. 

The method tested is a modification of the commonly 

used method o:f Noyes and Bray ( 1948). In this procedure, after distilling selenium as the tetrabromide, excess bromine is reduced by sulfur dioxide, and selenium 

is then precipitated :from 6N hydrobromic acid with 

hydroxylamine hydrochloride. 

The completeness of precipitation was tested using 

as a trac~r selenium-75 (High Specific Activity) obtained from the Oak Ridge National Laboratory. The 

counts o:f filtrates from the precipitation procedure were 

compa.red with those of reference solutions. Counting 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-43,5 D-395 

was done in n. scintillation counter using as the detector 

a well-type 2-inch thallium-activa.ted sodium-iodide 

crystal 

Precipitations were made in 25-ml volmnetric flasks. 

Eftch solution had tt vol mne of 20 ml, was 6N in hydrobromic acid, 1t.nd conta.ined 0.5 ml of free bromine. Precipitations were made by bubbling sulfur dioxide into 

the solutions to reduce the bromine, adding 1 1nl of 10 

percent hydroxylamine hydrachloride, and then heating .on the sten,m bath for two hours. After the solution stood overnight, the volumes were adjusted to the 

nmrk with wftter. 

The quantities of selenium taken ranged from 0.19 

to 519 1-tg, corresponding to a concentration range of 

0.009 to 25 ppm. (parts per million) at the time of precipitttti.on. The two lowest levels of selenimn tested 

were prepn.red by diluting the ORNL solution of 

selenium-75. The selenium content of these solutions 

was ca.lmtla.ted from the specific activity of the isotope 

solution. The higher selenimn samples were prepared 

by enriching inactive selenium solutions with 

selenium-75. 

Prior to counting, parts of all the precipitttted solut·.ions were filtered through Selas No. 01 porous porcelain crucibles. The solutions with the two lowest levels 

were n.lso filtered through dry l\1illipore type HA filters. 

Five-milliliter aliquots of each of the filtered. solutions were counted in glass vial containers for five 

rninutes. For· cornp1u·ison, counts were also made of 

appropt·intely diluted control solutions. The data are 

~urnrn1u·ized in table 4:31.1. 

The experiment's show that selenium, in concentrations as low as 0.9 ppm; is quantitatively precipitated 

with hydroxylamine hydr00hloride and may be quantitatively filtered with a porcelain or l\1illipore filter. 

There is a decrease in the percentage of selenium 

precipitated at lower initial concentrations, but precipitation is nevertheless 99.0 percent complete in solutions containing 0.09 ppm selenium and 80 to 90 percent complete in solutions containing 0.009 ppm 

selenium. 

TABLE 431.1.-Precipitation of selenium, 

Selenium Activity of filtrate Selenium 

taken Initial unprecipi- Completeness of 

(micro- activity 1 tated precipitation 

grams) Porcelain Millipore (micrograms) (average percent) 

filter filter 

-

0. 19 197 42 24 0. 032 83 

. 19 197 22 17 . 019 90 

1.9 2062 19 16 . 017 99. 1 

1.9 2062 27 19 . 021 98. 9 

19 2 20620 95 -------- . 087 99. 5 

19 20620 80 -------- . 074 99. 6 

69 20620 17 -----·--- . 056 99. 9 

69 20620 13 -------- . 043 99. 9 

119 20620 14 -------- . 080 99. 9 

219 20620 7 -------- . 074 99. 9 

219 20620 7 -------- . 074 99. 9 

519 20620 3 -------- . 078 100. 0 

519 20620 :3 -------- . 078 100. 0 

1 Register counts (512 scale) for 5 minutes given by 5-ml 

aliquots (corrected for a background of 7 counts). 

2 Calculated from counts of diluted spiking solution. 

REFERENCE 

~oyes, A. A., and Bray, ,Y. C., 1948, A systen1 of qualitative 

analysis for the rare elements: New York, l\'Iacmillan Co. 
D-396 GEOLOGICAL SURVEY RESEARCH 1 9 61 

432. EVALUATION OF HYDROLOGIC TRACERS 

By L. L. THATCHER, Washington, D.C. 

Several type-s of tracer substances with different 

characteristics are available for the study of the move· 

ment of water in nature. Although no single tracer is 

completely applicable to the diverse problems of hydrologic movement, one group of tracer substances presents a broader spectrum of applicability than the 

others. This is the group of isotopic tracers made up 

of the stable isotopes of oxygen and hydrogen and the 

single radioactive isotope of hydrogen with mass 3, 

tritium. The superiority of these tracers. is due to the 

fact that they are physically incorporated into the 

water molecule; therefore, they exhibit essentially the 

same physical and chemical properties as the normal 

water molecule with mass 18. 

While it is generally desirable to use an isotope of 

oxygen or hydrogen for tracer purposes in the hydrosphere, the situation sometimes arises that some other 

tracer 1nust be used because of cost, public reaction 

against radioisotopes, or other practical consideration. 

It is then desirable to use a tracer substance that has a 

minimum of adsorption loss or other adverse environmental reaction; in other words, one that behaves like 

tritium. Some studies have been undertaken to develop a suitable test method whereby satisfactory conventional tracers for a particular environment might be 

identified. Studies were made in a montmorillonite 

environment· using an equilibration method. It was 

known from previous research that the degree of adsorption of the tracer substance by montmorillonite 

could be related on a semiquantitative basis to the relative rates of movement between the tracer substance 

and the parcel of water originally associated with the 

tracer. As the adsorption effect on a, particular tracer 

increases, the retardation of the tracer with respect to 

its labeled water front increases. Conversely a tracer 

that. shows no adsorption in equilibrium tests generally 

shows little or no retardation in rate of movement tests 

with columns. Actually these are empirical relations 

which cannot be formulated precisely in mathematical 

terms at the present status of exchange and sorption 

studies. However, a useful empirical tool is provided 

here to permit the rapid laboratory evaluation of substances for their potential utility as hydrologic tracers. 

A series of substances selected for their overall potential as tracers because of their intense color or 

fluorescence, water solubility, and chemical stability 

was compared against tritium in an equilibrium experiment. Each tracer was equilibrated with 1 gram of 

A. P. I. Inontinorillonite (No. 23) suspended in 10 ml 

of distilled wa.ter. The concentration of· tracer substance was measured before { Oo) and after ( Ot) equilibration and the absorbance ratio, A, was evaluated: 

A _ol 

-oo 

Geiger counting was used for the tritium measurement 

and spectrophotometry was used for the dye tracer 

measurements. The results are summarized in the following tabulation: 

Tracer Co Ct A 

Tritiated water __________________ 87 83 . 95 

Thiazol yellow __________________ . 49 . 32 . 65 

Fast crimson ____________________ . 81 . 83 1. 02 

Rhodamine B ________________ .. __ 1. 076 . 016 . 015 

Fuchsin ________________________ . 312 . 219 .7 

Methyl green ______________ ·- ____ . 260 . 028 11 

Aurin tricarboxylic acid __________ . 491 . 200 . 41 

Potassium permanganate __ .. ______ 1. 51 . 84 . 57 

Potassium dichromate ____________ . 90 . 34 . 38 

Methyl blue ____________________ 1. 22 . 05 .4 

Fluorescein __ .. ___________________ 1. 05 1. 05 1.0 

On the basis of the above tests it was indicated that 

Fast crimson and fluorescein possessed the best tracer 

characteristics of the dye group. In similar tests with 

other media, however, fl_uorescei:h gave relatively high 

adsorption loss. Several tests with Fast crimson indicated that .it generally exhibited less adsorption reactivity than other dyes and tended to move with a 

minimum of retardation in columns tested with porous 

media. In short, its overall hydrologic behavior is similar to that of tritium. Thus, Fast crimson appeared 

to present considerable potential as a tool for laboratory· tracer studies. In particular, it might be added 

to tritium-labeled water to provide an approximate 

visual indication of the movement of the tritium front, 

which would be of. considerable value in laboratory 

studies inasmuch as it would minimize the collection 

and a.nalysis of unnecessary eluates and other fractional 

samples in laboratory model tests. 

The effectiveness of the experimental approach outlined above, whereby the potential value of tracer substances as accurate indicators for the rate of movement 

of water may be screened by equilibrium experiments, 

was further tested by column experiments with Fast 
SHORT PAPE'RS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293~4,3·5. D-397 

crimson and tritium. A column was filled with a mixture of 20 percent montmorillonite and 80 percent Ottawa sand, and then saturated with water. The top 

inch of the column was charged with a mixed tracer of 

tritium and Fast crimson and the mixture was eluted 

through the column. Ninety percent of the tritium and 

dye elution was found in the first 20 ml of eluate, and 

the concentrations of suc.cessive 5 to 6 ml portions of 

eluate were used to determine the time-concentration 

relation. Maximum concentrations were found in the 

first 5- to 6-ml part; the tritium peak. was 0.4 ml behind 

the Fast crimson peak. The tritium peak was more 

sharply defined and exhibited less tailing. It was concluded that the two peaks were practically coincident 

within experimental error a..nd that Fast crimson provides· a useful visual indicator for tritium movement 

in laboratory studies with montmorillonite. This conclusion has been confirmed by further tests. 

433. GRAVIMETRIC DETERMINATION OF SILICA IN CHROMITE AND CHROME ORE 

By JosEPH I. DINNIN, Washington, D.C. 

Results obtained by the colorimetric determination of 

silica in chromite and chrome ore have been found to 

be several tenths of a percent (absolute). higher than 

the results obtained by the usual gravimetric procedures. Although the uncertainty this produces in the 

analysis of ~t highly siliceous ore may be relatively unimportant, it may be significant in the analysis of a 

purified chromite. · 

A purified chromite usually contains less than 1 percent silica. An error of several tenths of a percent 

(absolute) may represent as much as 50 percent of the 

silica present. Besides affecting the calculation of the 

impurities in the 1nineral this ma.y seriously affect the 

mineralogical and geological interpretations that are 

based upon the analysis. 

If the lower gravimetric result is caused by incomplete recovery of the silica, this may also cause a positive error in the determination of alumina; silica that 

has not been completely dehydrated is usually recovered and reported a.s alumina in the gravimetric determination of alumina. 

Most of the gravimetric methods that have been desci'ibed for the determination of silica in chrome ore 

rely upon a. single dehydration for the recovery of the 

silica ( I-Iartford, 1953). In order to 'determine whether 

~tppreciable quantities of silica were unrecovered after 

a sirigle dehydration, a series of chrome ores and standard samples was subjected to a double dehydra.tion, a.nd 

the quantity of silica recovered after each dehydration 

was separately recorded. Slight variations of the conventiona .. l procedures were used for the determinations. 

In an attempt to conform to common practice, glass 

beakers rather than platinum dishes were used for the 

dehydrations so as not to prejudice the results towards 

low recovery of silica. Reagent and apparatus blanks 

were determined with each method of analysis used. 

In spite of the fact that no effort was made to limit contamination, blanks containing no greater than 0.2 mg 

Si02 were found after a double dehydration. 

The methods used for the gra.vimetric determination 

of silica were variations of those that have been described for the determination of silica in chromite and 

chrome ore. 'Vhere fusions were made, they were performed with sodium peroxide in zirconimn crucibles. 

The alkaline melts were acidified in polypropylene 

beakers and then transferred to Pyrex beakers for 

evaporation and dehydration. Silica precipitate washing techniques were standardized so as to limit the 

solubility effects of the wash solution; all precipitates 

were washed 10 times alterna,tely with hot water and 

hot 5-percent hydrochloric acid. All ignitions of the 

precipitated silica and all volatilizations with hydrofluoric acid were performed in platinum crucibles. A 

· semimicro-balance was used for all weighings; weights 

were recorded to the nearest 0.01 mg. 

The results of the gravim.etric determination of silica 

by the various m.ethods used are compared on. figure 

433.1 to the results obtained by spectrophoto1netric 

~tnalysis a .. nd by independent analysis. In almost every 

instance, significant amounts of silica were recovered 

after a second dehydration. In general the greatest 

a .. mount of silica was recovered after a second dehydration \vith perchloric acid; the least amount was recovered after a second dehydration with hydrochloric 

acid. 

The lowest total amount of silica was recovered after 

decomposition of the sample with perchloric acid. The 

amounts recovered could, however, be increased by pro.:. 
D-398 GEOLOGICAL SURVEY RESEARCH 1961 

gO·r-------~EX~P~~"N~ATrulon.N~----------------------------­

~ Si02 recovered as determined by 

w!:: 80 a. Independent laboratories 

b. Spectrophotometric method 

::::!: 

~ 0 Si02 recovered by first dehydration 

i3 10 I .... 

0 

::::!: 60 c( 

0: 

(!) 

0: 50 LLI 

0.. 

0 

~ 40 LLI 

> 0 

~ 30 0: 

Si02 recovered by second dehydration 

c. HCI04 decomposition and double 

dehydration with HCI04 

d. Na20 2 fusion and double dehydration with HCI04 

e. Na20 2 fusion and double dehydration with H2S04 

f. Na20 2 fusion and double dehydration with HCI 

. ~ 

• II 

abcdef abcdef abcdef abcdef 

METHOD OF DECOMPOSITION AND DEHYDRATION 

FIGURE 433.1.-Recovery of silica from 4 samples of chromite 

by various methods of decomposition and dehydration. 

longed treatment of the ignited silica with hydrofluoric 

acid in a covered crucible. Presumably, attack of the 

sample with perchloric acid had not completely decomposed the quartz or refractory silicates; silica in the 

refractorie-s w~ts not cmnpletely volatilized by. the brief 

treatment with hydrofluoric acid. 

Dehydra.tion of the silica with hydrochloric acid also 

resulted in lower total recoveries of silica. Although 

no additional amow1t could be recovered by a third dehydration with hydrochloric acid, additional a.mounts 

could be recovered by dehydration of the same solution 

with sulfuric acid. 

The dehydration action of hydrochloric acid was 

further tested in the following manner: 4 1-g portions 

o£ a purified chromite, estimated by colorimetric analysis to contain 5 mg Si02 per g, were enriched with 

additional amounts of pure quartz. The recovery of 

silica after each of 2 dehydrations with hydrochloric 

acid and an additional dehydration with sulfuric acid 

is shown on figure 483.2. Although little additional 

silica was recovered after a second dehvdration with 

hydrochloric acid, significant amorints ~f silica were 

recovered after an additional dehydration with sulfuric 

acid. Failure of the sulfuric acid dehydration line to 

go through the origin of the graph (fig. 433.2) is due 

to either an incomplete recovery of the silica or an 

error of 0.2 percent (absolute) in the colorimetric 

analysis. To test ''"hich of these two alternatives was 

the more likely, the follo,Ying procedure was followed: 

Various amounts of a purified chromite, estimated by 

colorimetric analysis to contain 1.03 percent Si02 , were 

£used with sodium peroxide; silica was dehydrated 

with hydrochloric acid in a polypropylene beaker; 

- 16 Ql) 

.s 

0 

~ 14 

0 

< 

2 

0 2 4 6 8 10 12 14 16 18 

Si02 RECOVERED (mg) 

FIGURE 433.2.-Recovery of silica in chromite after enrichment 

with varying amounts of quartz. a, single dehydration with 

hydrochloric acid; b, double dehydration with hydrochloric 

acid; and c, double dehydration with hydrochloric acid followed by dehydration with sulfuric acid. 

and the filtrate was dehydrated with sulfuric acid in a 

Pyrex beaker. The silica recovered after each dehydration was weighed separately. The silica recovered by each method of dehydration was then 

plotted against the sample weight taken as shown on 

figure 4;33.3. Extrapolation of the plotted lines indicates that approximately · 4 mg of silica, remains in 

solution after dehydration ''"ith hydrochloric acid; an 

additional 2 mg of silica is recovered after a. second 

dehydration with sulfuric acid. However, approximately 2 mg of silica remains in solution and is not 

recovered. 

The gntvimetric detennination of silica on a 1-g 

portion of this sample would normally be reported as 

0.8 percent; repeated colorimetric anaJysis reported 1.03 

percent Si02 . The difference, 0.2 percent (2 mg per 

g), is almost. coinpletely accounted for by the 2 mg of 

silica estimated to remain unrecovered in the solution. 

REFERENCE 

Hartford, ,V, H., 1953, Industrial chrome ore analysis: Anal. 

Chemistry, v. 25, p. 290--295. 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293..-4,3·5 

16 

14 

'@ 

512 

0 

w ffi 10 

> 0 

u 

~ 8 

< u 

:; 6 u; 

4 

1.0 1.5 2.0 

WEIGHT SAMPLE TAKEN (g) 

FroUim 433.3.-Recovery of silica from various amounts of 

chromite. 

D-399 

434. COMPARISON OF DRAINAGE DATA OBTAINED BY THE CENTRIFUGE AND COLUMN DRAINAGE METHODS 

By R. C. PRILL, Denver, Colo. 

Wot·T.: done in coope·rat-ion ·with the California Depa .. rhnent of Water Resottrce/l 

In studies of specHi.c yield of wuter-bea.ring materials, 

a. knowledge of the moisture distribution during drainu.ge is important. I-:Iowever, procedures for estimating 

the moisture distribution pattern are still in the development stage. Numerical procedures (IGute, 1952; 

Childs, 1960) that require moisture-tension a.nd unsn,tura.ted-permeability measurements have been the 

pr.incipa.l approach to this problem but as yet are very 

expensive and provide only n.pproxima,te solutions. Use 

of the centrifiuge has been considered for son1e time to 

be a, prom.ising method of estin1ating moisture distribution after different periods of drainage (Miller and 

Miller, 1055). Because there has been only limited research on this method (Slobod and others, 1951; ~tfarx, 

1956) the l[ydrologic Labora.tory, Denver, Colo., has 

been evaluu.ting use. of the centrifuge for this purpose. 

In the present pa,per, a, compttrison is made of 1noisture 

contents of samples after centrifuging a.nd after drain-

~tge by grn.v.ity. 

Three sizes of glass beads, 0.47 mm (medium sand 

size), 0.120 mm. (very fine sand size), a.nd 0.036 min 

( cottrse silt size) (fig. 434.1) were packed in columns 

and were saturated. The columns of beads were drained 

at 20° C until drainage had virtually ceased, which was 

1 da.y for the 0.47-mm bea,ds, 2 days for the 0.120-mm 

~ 

J: 

(!) 

w 

~ 

>-

CD 

..... 

z 

w 

(.) 

0:: 

w 

0.. 

w 

> 

i= 

< ...J 

:::::> 

~ 

~ 

:::::> 

(.) 

100 

90 

80 

70 

60 

50 

40 

30 

20 

10 

§ 

0 

T ( I / T 

Curve A- Glass beads (0.036 mm) I 

I 

Curve 8- Glass beads (0.120 mm) I 

I 

Curve C- Glass beads (0.470 mrn) 

AI 8 c 

7 

1 

I 

J 1 

_/ 

I 1 l---v 

8 

0 

0 

0 ~ 8~ 10 ...... 

q 0 0 0 

0 

LO 

N 

0 

PARTICLE-SIZE DIAMETE~. IN MILLIMETERS 

1/ 

0 

0 

LO 

0 

l!~IGURE 434.1.-Particle-size distribution of glass beads. 
D-400 GEOLOGLCAL SURVEY RESEARCH 19 61 

beads, and 3 days for the 0.036-mm beads. After drainage, the columns were separated and the moisture content determined gravimetrically for each segment (fig. 

434.2). 

In the centrifuge test, 5..:gra,m samples of the three 

sizes · of glass beads ( 0.8 em thick) were placed in 

Gooch crucibles, and after saturation the samples were 

centrifuged for 1 hour at a temperature of 20° C and 

accelerations between 1 and 1,000 times the acceleration 

due to earth's gravity (g). The observed moisture content versus applied acceleration is shown on figure 434.3. 

Assuming that the columns were drained long enough 

so that equilibrium prevailed in them, the moisture 

tension at any point in the drained media would be 

equivalent to the height above the water table. Thus, 

for the data shown on figure 434.2, the tension a.t the 

top of the zone that is at or near capillary saturation 

would be approximately 72, 2L1, and 6 inches of water 

en 

w 

:I: 

u 

110 

100 

90 

80 

~ 70 

~ 

w 

...J 

~60 .... 

0:: 

w 

.... 

< 

3: 50 w 

> .g 

< 

.... 40 :I: 

(!) 

Uj 

:I: 

30 

20 

10 

0 

I 

I 

14 \ 14 I 

I 

I '[\_ I 

I 

I ~ 

I '~ I 

I Glass beads (0.036 mm) 

I t'--. I 

I 

I 

1 

I 

I 

~ f'r 14 I 

i 

0 Q • A ~ 

~ 

\ L 

:\ 

> ~· I ~ > ~~~ Glass beads (0.120 mm) 

~\ ~ 

~ ~~ " r--- ' 

~~ - r-' Glass ~ads (0.470 mm) ~. I I 

4 8 12 16 20 24 

MOISTURE CONTENt. IN PERCENT OF DRY WEIGHT 

FIGURE 434.2.-.Moisture retained after gravity drainage. 

26 

for the 0.036-, 0.120-, and 0.47-mm beads, respectively. 

The relationship between length of drainage time to 

acceleration for the two tests on identical media and 

fluids is expressed by the formula: 

(1) 

in which t1 and ~ are the times under accelerative fields 

1 or 2; and a1 and U-:l are rates of acceleration due to 

force fields applied to sample. 

According to equation 1, 100 hours of drainage from 

a stationary column, for which a1 =g, would be simulated by 1 hour of centrifuging a.t an acceleration of 

10 g's; and 10,000 hours of drainage from a stationary 

column would be simulated by 1 hour of centrifuge 

drainage at an acceleration of 100 g's. 

Provided the centrifuged sample has been accelerated 

for a long enough time, the moisture tension at any 

distance from the bottom of the sample can ~e calculated from the formula . .-

(2) 

in which T is tension, in centimeters of water; w is 

angular velocity, in radians per second; o is acceleration 

of gravity, in centimeters per second per second; r1 is 

distance from bottom of sample from center of rotation, 

in centimeters; and r2 is distance of specified point in 

. sample from center of rotation, in centimet.ers. 

On figure 434.3, the flat parts of the curves at the 

higher moisture contents represent near-capillary saturation. As acceleration is increased, the moisture 

tension at the top of the sample increases according 

to equation 2. As the moisture tension at the top of 

the sample exceeds the height of capillary saturation, 

the moisture content decreases rapidly with increasing 

acceleration. Thus, the lowermost moisture content of 

the flat segments of the curves originating along the left 

side of figure 434.3 may be viewed as the moisture content corresponding with the maximum height of capillary saturation, and the accelerations at which the 

curves break may be substituted in equation 2 to determine that height. The-curve breaks at an acceleration 

of about 235 g's for the 0.036-mm, 74 g's for the 0.120-

mm, and 15 g's for the 0.47-mm glass be~ds. Tensions 

of 75, 24, and 5 inches of water are obtamed for these 

points from equation 1. These tensions may be compared with similar breaks in the moisture content profiles of figure 2 at 72, 24, and 6 inches of wa.ter. 

The data presented above are evidence of the applicability of formula 2 in centrifuge drainage. This suggests the possibility of using the same basic procedure 
SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 293-43.5 D-401 

..... 

0 

.... 

z 

w 

() 

~t::: 

~~~ 

0:: 1\) 

~ 0 ~ 

\ 

..... 1\ 

Glass beads 

(0.470 mm) 

-v r 

1\. 

I~ 

~ \ ~lass beads 

" ~ 

~ 

...... 

z 

w 

.... 

z 

8 

w 0 0:: "" 1\ ~0.036mm) 

Glass beads 

(0.120 mm) ~ 

::J 

Iii 

5 

:e 

0 

1 

~~ 

~ 

10 

........ ......._ 1-- ~ 

- . 100 

~ """ N ) 

1'--. P-

~ '11 ,.,. -11 -- ... 1000 

ACCELERATION, IN TERMS OF EARTH GRAVITY 

FIGURE 434.3.-Effect of acceleration on centrifuge moistt~re content. 

for centrifuge scale modeling of drainage by gravity, 

and such experiments a.re presently being made. A 

modificn,tion of formula. 2 is used for relating the cen-. 

trifuge sn,mple thickness to the thickness of the materia] 

being drained by gravity, and formula. 1 is used for 

relating time of drainage by the two methods. 

REFERENCES 

Childs, lD. C., 1!)60, 'l'he nonsteady state of the water taiJle in 

drained lnnd: .Tour. Geophys. Research, v. 65, no. 2, p. 780-

782. 

Klute, Arnold, 1952, A numerical method for solving the flow 

equation for water in unsaturated materials: Soil Sci., 

v. 73, no. 2, p. 105-116. 

:Marx, .J. ,V., 1956, Determining gravity drainage characteristics on the centrifuge : Am. lust. Mining Metall. Petroleum 

Engineers Trans., v. 207, p. 88-91. 

:\filler, E. E., and Miller, R. D., 1955, Theory of capillary tlow1. Practical implications: Soil Sci. Soc. America Proc., v. 

19, no.3,p. 267-271. 

Slobod, R. L., Chambers, Adele, and Prehn, ·w. L., Jr., 1951, Use 

of centrifuge for determining connate water, residual oil, 

nnd capillary pressure curves of small core samples : Am. 

Inst. Mining Metall. Engineers Trans., v. 192, p. 12.7-134. 

435. REMOVAL OF MANGANESE FROM SOLUTIONS PRIOR TO DETERMINATION OF CALCIUM 

AND MAGNESIUM 

By LEE C. PECK and VERTIE C. Sl\IITH, Denver, Colo. 

The colloidal hydrated manganese dioxide precipitate formed by heating a, manganese solution containing 

ammonirun persulfate is readily filterable if zirconium 

hydroxide is used as a gathering agent. 

In silicate analysis, after solut.ion of the sample and 

after separation of silica and the ammonium hydroxide 

group, a, solution is obtained that contains manganese, 

cuJcium, n,nd magnesium (l(olthoff and Sandell, 1952, 

p. 702-704). Although a prior separation of manganese 

simplifies determinations of calcium and magnesium, 

such a separa.tion is seldom made because no. rapid reliable method is known. Usually these elements are 

precipitated in the presence of manganese and suitable 

corrections are made for the amounts of maJlganese coprecipitated. 

It is well known that ammonium persulfate quaJltitatively precipitates manganese as hydrated ma.p.ganese 

dioxide from ammoniacal ·solutions containing large 

amounts of ammonium salts, but the colloidal character 

of the precipitate makes this method unsatisfactory. 
D-402 GEOLOGICAL SURVEY RESEARCH 19 61 

The filtration is tedious and the precipitate tends to 

pass the finest paper. If zirconium hydroxide is used 

to gather the precipitate, filtration is rapid through a 

coarse-textured paper and the removal of manganese 

is complete. Paper pulp added to the solution before 

filtration prevents channeling of the precipitate. 

Sulfate ions do not cause interference in subsequent 

operations.. If calcium is separated by a double precipftation with ammonium oxalate, no· calcium sulfate is 

present in the final precipitate. Barium and strontium 

behave much as they do if manganese is not removed. 

In amounts of 10 mg or less, barium oxide does not 

coprecipitate with either calcium or magnesium. Much 

of the strontium present coprecipitates with calcium 

and most of the remainder with magnesium. 

Calcium does not coprecipitate appreciably with hydrated manganese dioxide but magnesium does. Coprecipitation of magnesium is minimized if the manganese is precipitated from acid solution, but the precipitation is incomplete. The best separation is obtained if the solution is acidified,. heated, then made 

ammoniacal and heated for a short additional period. 

Where the manganese oxide content of a silicate is 2 

percent or less, the error in the magnesium determination caused by the coprecipitation of magnesium with 

manganese can be tolerated (table 435.1) ; but where the 

manganese oxide content is greater, the error is large 

and a double precipitation should be made. If a double 

precipitation is necessary, each precipitation is made 

as described in the following procedure except that a 

larger initial volume of solution is used. The first preTABLE 435.1.-Average amounts of magnesium coprecipitated with 

manganese 

[In milligrams] 

Amount magnesium oxide coprecipitatcd for indicated 

Amount manganese oxide taken amounts magnesium oxide taken400 100 50 10 

20 _____________ 0. 30 0. 20 0. 15 0. 10 5 ______________ . 10 . 06 . 05 . 05 

cipitate is dissolved in a dilute hydrochloric acid solution containing sodium sulfite. 

Evaporate to a volume of 100 ml the combined acidified 1Htrates from the ammonium hydroxide group determination. 

Add 1 ml of an acidified 5 percent zirconyl chloride octahydrate 

solution and about 0.1 gram of dry-dispersed paper pulp. 

Make the solution ammoniacal to bram cresol purple; then 

make it just barely acid with 1 to 1 hydrochloric acid. Add 1 

gram of ammonium persulfate; stir the solution and heat it on 

the water bath for 20 minutes. Add 1 ml of ammonium hydroxide; then heat the solution 5 minutes more. 

Filter the solution at once through a 7-cm coarse-textured 

paper. Wash the inside of the beaker three times with hot 

2-percent ammonium nitrate solution and transfer the washings 

to the paper. Finally, wash the precipitate on the paper 10 

times with the same wash solution. 

Discard the precipitate and reserve the filtrate for the determinations of calcium and magnesium. 

REFERENCE 

Kolthoff, I. lVI., and Sandell, E. B., 1952, Textbook of quantitative inorganic analysis, 3d ed.: New York, Macmillan. 
SUBJECT INDEX· 

A 

[Numbers refer to articles ; finding list of articles page numbers follows author index) 

Article Article 

Article 

Arrial photographs, new stereoscope for viewIng In field........................ 426 

Alaska, Cape 'l'hompson engineering geology. 418 

geologic mnp ... --------------------- 418 

Copper H.lver basin, hydrology___________ 353 

Delt.n lllver nrea, glnclntlon.............. 357 

Klglunlk Mountains, economic geology___ 356 

geologic map .... --------------------- 356 

La touche Island, geomorphology ..•.• _.. 355 

Lisburne .Hills, geologic map._ .. --------- 354 

structuml geology____________________ 354 

j\<llnto Jqnts, geophysics •••.•..•.•....... ·. 383 

Portage Glacier, recession................. 358 

'l'alkcetna Mountains, paleontology______ 374 

Yukon-Koyukuk lowlnnd, engineering 

geology-------------------------.. 419 

geomorphology.---------------------- 419 

Algae, CnJnbrlan, Utnh ----------------------- 380 

Algal'Ohn, ofTcct or on ground water........... 377 • 

Alkalic rocks, nssoclat.ed with gabbrolc sills .. ~ 344 

Alluvium, ground water ln................... 372 

Alt.emt.lou, hydrothermnl, association or' not 

springs with..................... 321 

mecbnnlsms of temperature change.__ 412 

system Na20-AhOa-SI02-lhO........ 408 

t.horlum fleposltlon................... 293 

Ammonoids, Permian, California............. 375 

Anhydrite, lntrrnet.lon with solutions or 

strontium al'd cesium............ 407 

Origin or mottled structure ..•.••.. -·---.-- 410 

Arizona, CIU'lstmas quaamngle, economic 

geology .••..... ---------·-·····___ 397 

geochemistry .... -·--------·-......... 397 

Copper Mine-Preston Mesa area, hydrology----·----------------·--------· 321 

l~cldmnn, cconomlc geology ..... --------- 410 

!<'our Corners area, paleobotany__________ 382 

Olobc, petrology_ .... ---·-·-------------- 320 

Superior, petrology_______________________ 320 

'l'ucson, geologic map .. ___________________ 384 

geophysics ....•..•. _ .. _________ .. __ .. _ 384 

'I' win Buttcs quadrangle, geologic map .. _ 385 

geophysics .....•. ·-·------------------ 385 

Arsenic, in gold ore veins, Wyoming__________ 405 

Ash flows, finttenlng ratios of pumice frag- ment.s ..• __ .• _. __ . _. _____ •. _____ .. 322 

See also 'l'ufY, welded. 

Asphnlt.lte, umnlum-bcnrlng nodules In 

dolomite .. _.----------------··-·- 402 

A t.Jantic Ocean, western, mngnetlc profiles._.. 396 

Au~tmlla, lllllngrovl' coasts................... 365 

B 

Bambui series, Bahia, Bmzll................. 362 

Barium, flame photometric determination oL 428 

Bnsult, g~ound water In ..... ------------·---- 420 

lleekmantown dolomite, St. Lawrence County, N.Y •. -------------------·---- 315 Belt series, Idaho batholith area._____________ 345 

Bermuda, magnetic profiles__________________ 396 

Blcnrbonate, In surface water_________________ 406 

Bikltalte, dehydrntlon and decomposition.... 413 

Bismuth, contact-metasomatic deposits, Alaska __ -----------·------·------·--__ 356 Uonnevlllc, glacial Lake, ago__________________ 334 

strntlgraphy ------------------------ 332,333 

Bmchlopo~s, Permian, Callfornla_____________ 375 

Brazil, Bahia, Chapada Diamantina, economic 

geology ____ • ____ ._. _______ . _____ ._ 362 

Tucano basin, economic geology______ 363 

Minas Gerais and Sao Paulo, Pocos de 

Caldas Plateau, economic geology_ 364 

Breccia, associated with impact craters_______ 342 

Brines, oil-field, metals in._------------------ 398 

Buried valleys, ground water in ____________ 350,351 

Butte Spring member. See Oak Spring formation. 

c 

Calcnlkallc rocks, proposal for clarificntion or 

use of names------·--------------- 409 

Calcium, in surface water_____________________ 406 

Calcium and magnesium, removal of manganese from solutions oL •••••.•. _ 435 

California, Alameda Plain, hydrology __ ._._._ 386 

Cymric oil field, geochemistry ____________ · 398 

Funeral Mountains, geologic map________ 323 

geomorphology-------·--------------- 323 

In yo Range, paleontology __ -------------- 375 

Klamath Mountains, hydrology__________ 325 

Menlo Park, precipitation, chemical character oL---------··--------------- 304 

Northern Coast Ranges, hydrology_______ 325 

San Joaquin Valley, sedimentary petrology---------------·----------- 324 

Sierra Nevada, glacial geology____________ 332 

Southern Cascndes, hydrology------------ 325 

Cambrian, Utah, Tule Valley________________ 380 

Caplllarity, comparison or centrifuge and 

gravity determinations___________ 434 

Carboniferous, Nevada, Nevada Test Site____ 328 

See also Mississippian, Pennsylvanian. 

Caves, deposits or phosphate rock____________ 367 

ground water in.···---------------------- 308 

Centrifuge, in est.mrting moisture distribution 43•1 

Cesium, reaction with anhydrite_____________ 407 

Cherry Canyon formation, Getaway limestone 

member, Culbertson County, Tex. 379 

Chichali formation, Surghar and Salt Ranges, 

Pakistan .. _---------------------- 371 

Chilson member. See Lakota formation. 

Chloride, in surface water____________________ 406 

Chlorite, association with hot springs_________ 331 

interlayered in evaporite •. _______________ 403 

Chrome oro, gravimetric determination or 

silica ln ...... -------------------- 433 

Chromite, chemical method of distinguishing 

from ilmenite and magnetite_____ 430 

gravimetric determination of silica in_____ 433 

Claiborne group, Jadksondomearea, Mississippi. 31'l 

Clay, effective ran diameter and fall velocity__ 300 

in evaporite __ ---------------------------- 403 

Clay minerals, effect on compaction processes. 324 

in hot springs·-------------"-------------- 331 

Coal, minor-clement associations_____________ 411 

Cockfield formation, Jackson dome area, 

Mississippi__ _____ -------------___ 312 

Cohansey sand, Wharton Tract, N.J._________ 313 

Colorado, eastern, paleontology and stratigraphy .. -------------------------- 352 

Paradox basin, economic geology_._ _ _ _ _ _ _ 337 

San Juan Mountains, geologic map_______ 326 

volcanism.--------------------------- 326 

southeastern, geochemistry_______________ 414 

southwestern, paleobotany_.------------- 382 

Wet Mountains, petrology.-------------- 293 

Column drainage, in estimating moisture 

distribution._-------------------- 434 

Comanche Peak limestone, Lea County, 

N. 1\fex. ------------c-----------·- 338 

Connecticut, southeastern, mineralogy_------ 399 

Conodonts, Permian, Texas ___________ !______ 379 

Continental shelf, magnetic profiles .• --------- 396 

Cook MountLin formation, Jackson dome 

area, Mississippi..________________ 312 

Copper, contact-metasomatic deposits, Alaska. 356 

electrical prospecting for, Michigan_______ 389 

Cotter formation, Kansas-Missouri-Oklahoma ________ ---------·----------- 414 

Craters, Alaska, Project Chariot high-explosive test__________________________ 418 

Colorado, Lake City caldera______________ 326 

Silverton caldera_____________________ 326 

impact _______ ..•.... --·------·----.-----. 417 

Moon .•• _-------------------------------- 361 New Mexico, Valles caldera______________ 340 

.Cretaceous, Alaska, Llshourne Hills__________ 354 

Talkeetna Mountains________________ 374 

Great Plains, northern___________________ 352 

New Mexico, Lea CountY---------------- 338 

South Dakota, Black Hills_______________ 349 

western United States____________________ 382 

Wyoming, Black Hills.___________________ 349 

Current meter, opticaL ..•.• ------------------ 424 

D 

Deflation, as a cause of erosion._______________ 378 

Deformation, associated with impact craters.. 342 

caused by earthquakes.------·--------- 346,347 

relation to intrusion, metamorphism, and 

metasomatism ...• ------_--------- 345 

Devils Gate limestone, Nevada Test Site, N ev _ 328 

Devonian, Arizona, Christmas quadrangle.... 397 

Nev:1da, Nevada Test Site________________ 328 

Utah, northern___________________________ 335 

Diamond districts, revised geology of, BraziL. 362 

Diatoms, Tertiary, Nevada___________________ 373 

Diorite, associated with alkalic rocks .•..• :... 344 

Dolomite, back-reeL _________________ -------- 402 

shatter cones formed by high-spe('d impact. 417 

Drainage, comparison or centrifuge and gravity 

methods _____________ --_---------- 434 

E 

Earthquakes, deformation by, Montana ____ 346,347 

Economic geology. See particular mineral 

~ame and under State names. 

Ecuador, mangrove coasts .•. ----------------- 365 

Eleana formation, Nevada Test Site, Nev.... 328 

Electrical prospecting, copper, Michigan.____ 389 

Electromagnetic surveys, Arizona, Twin Buttes quadrangle ... _____________ 385 

Engineering geology. See tmder State names. 

Erosion, deceleration by ash falls_____________ 370 

. deflation as cause.-----·------------------ 378 

Eskers, Alaska, Delta River area_____________ 357 

Etza formation, Carson Desert, Nev.......... 329 

Evaporites, In salt anticlines._---·----------- 337 

interlayed chlorite-vermiculite In_________ 403 

F 

Fall diameter of particles, definition .•. ------- 301 

significance .. __ --------------------------- 300 

D-403 
D-404 

Article 

Fallon formation, Carson Desert, N ev ______ 329, 330 

Fall River formation, Black Hills, South 

Dakota-Wyoming________________ · 349 

Fast crimson, as a hydrologic tracer__________ 432 

Faults and faulting, Alaska, Lisburne Hills___ 354 

lllinois-Kentucky mining district_________ 294 

Massachusetts, east-centraL ____________ 310,311 

Montana, Hebgen Lake ________________ 346,347 

Nevada, Roberts thrust__________________ 401 

New Hampshire, southern_______________ 311 

New Mexico, Valles caldera______________ 340 

Utah, northern___________________________ 335 

Feldspars, In hot spring deposits __ ----------- 331 

Feldspathization, potassic, relation to thorium 

deposition _________ -----------____ 293 

Flame photometry, determination of magnesium and barium_______________ 428 

determination of strontium_______________ 429 

l<'loods. See Surface water. 

Florida, Biscayne aquifer ___________________ 302,307 

Dixie County, mineralogy________________ 400 

western, paleontology_------------------- 376 

Fluorescein, as a hydrologic tracer_ .. _ .. _. __ .. 432 

Fluorine, In phosphatic rock__________________ 369 

Folds and folding, relation to distribution of 

lead-zinc mineralization __ -------- 296 

Foraminifera, Cretaceous, Alaska_____________ 374 

Tertiary, Florida_________________________ 376 

Fort Dodge formation, Fort Dodge, Iowa_____ 410 

Fredericksburg group. See Comanche Peak 

limestone. 

Fuson member. See Lakota formation. 

Fusulinids. Permian, California_ _ _ _ _ _ _ _ _ _ _ _ _ _ 375 

G 

Gabbro, associated with alkalic rocks----~---- 344 

Gas, from mineral springs ____ ... _____________ 353 

in relation to uranium deposits ..... ____ ... 295 

Geochemical, Investigations, alteration reaction 

in system Na20-Al20a-Si02-H20-- 408 

evaluation ofbydrolo?iC tracers___________ 432 

ground-water sources of radium concentrations ____________ -----~-------- 414 

precipitation, influence on chemical composition or surface water__________ 304 

surface water, western United States_____ 406 

See also under State names. 

Geochemical prospecting, copper. deposits 

beneath thrusts, Michigan_______ 401 

gold veins, Wyoming_____________________ 405 

Geomorphology. Sfe particular type of feature 

and under State names. 

Geophysical investigations, borehole methods_ 386, 

420 

overvoltage characteristics of pyrite crystaL 416 

well-loggfng methods ________ ·_____________ 386 

See also particular method and under State 

names. 

Geothermometry ______ -- ________ ------- ____ __ 412 

Getaway l'imestone. See Cherry Canyon 

formation. 

Gila group, Feldman, Ariz___________________ 410 

Glacial lakes. See Bonneville and Lahontan. 

Glaciers, multiple glaciation, Alaska__________ 357 

recession of, Alaska --------------------- 358 

Glaciofluvial deposits, ground water in _____ 350, 351 

· Glorieta sandstone, Grants, N. Mex__________ 421 

Gneiss, granitic, sphene content______________ 399 

Gold, geochemical surveying for, Wyoming___ 405 

Gravimetic methods, determination of silica 

in chrome ore and chromite_______ 433 

Gravity surveys, Alaska, Minto Flats _______ _ 

Arizona, Tucson ______ ------- ____________ _ 

Hawaii, Kilauea Volcano ________________ _ 

Maryland, Rockville quadrangle ________ _ 

Nevada, Clark County __________________ _ 

New Mexico, Rio Grande trough ________ _ 

Sangre de Cristo Mountains _________ _ 

Utah, southeast__------------------------

383 

384 

360 

388 

390 

392 

391 

393 

.IN.DEX 

Article 

Greenland, Brflnlund Fjord, geomorphology__ 366 

Green River formation, Wilkins Peak member, Flrehole Basin quadrangle, 

Wyoming __ ---------------------- 348 

Ground water, Alaska, Copper River Basin___ 353 

Arizona, Coconino County_______________ 321 

ourled ridge, influence on aquifers________ 321 

California, Alameda Plain________________ 386 

connate, oil-field brine____________________ 398 · 

cooling of hydrothermal fluids____________ 412 

discharge, by ph:·eatophytes______________ 377 

relation to drawdown_________________ 359 

domal structure, influence on aquifers____ 312 

effect of damming streams________________ 315 

Flo~ida, Dade County------------------ 302,307 

Hawaii, Oahu ____________________ ------ 359,377 

hydrochemical facies, mapping oL_______ 423 

Idaho, Snake River Plain ______ .:_________ 420 

in alluvium _______ ... __ .-----------------, 372 

in basalt__________________________________ 420 

in buried valleys_---------------------- 350,351 

in caves ____ ------------------------------ 308 

in glaciofluvial deposits_------.. --.. -.-- 350; 351 

Kansas, Manhattan______________________ 351 

south-centraL_------------------_____ 341 

Kentucky, Mammoth Cave______________ 308 

levee seepage______________________________ 307 

levels, dispersion-motivated fluctuations_ 302 

Mississippi, Jackson dome________________ 312 

moisture studies ________________________ 339,434 

New Jersey, Wharton Tract______________ 313 

New Mexico, Los Alamos County________ 339 

New York, St. Lawrence County_________ 315 

North Dakota, Stutsman County________ 350 · 

Oklahoma, western_______________________ 341 

porous media, mechanical vibratory 

packer ________________________ ._._ 305 

mechanics of flow ___________________ 303,386 

pressure-volume relation in clayey sediments __ --------------------______ 324 

quality, complexes of manganese__________ 415 

irrigation use. _____________ . __ ._______ 422 

radioactive waste, disposal of ______ . _ _ _ _ 420, 421 

radium concentrations in --------------.. 414 

relation to mineral springs________________ 353 

salt springs, circulation around___________ 341 

salt-water encroachment ____________ 302,303,386 

sea water, residual in basement complex rocks ___ . ___________ . _________ .___ 319 

Southern Rhodesia, Sabi Valley._. ___ .... _ 372 

subdivisions of a ground-water basin______ 336 

Texas, northern __ -----------------_______ 341 

Utah, Jordan Valley______________________ 336 

Virginia, Fredericksburg ________ . ______ . _ 319 

water-level contours, relation to streamflow------------------------------ 313 

wells, relation of discharge to drawdown 

in ________ ._______________________ 359 

Grouse Canyon member. See Oak Spring 

formation. 

Gypsum, origin of mottled struc~ure__________ 410 

H 

Halite deposits, removal through solution._.. 341 

Hawaii, Kilauea Volcano, geophysics_________ 360 

Oahu, hydrologY--------~-------------- 359,377 

Helmet fanglomerate, Twin Buttes quadrangle, Arizona ________________ ._ 384,385 

Hermosa formation, Paradox basin, ColoradoUtah_--------------------________ 337 

Hicks dome, Illinois-Kentucky_______________ 294 

Hot springs. See Thermal waters. 

Hydrochemical facies, techniques for mapping_ 423 

Hydrology. See Ground water, Surface water, 

and under State names. 

Hydrothermal fluids, mechanisms for cooling_ 412 

Article 

Idaho, central-eastern, paleobotany ________ . __ 

Snake River Plain, geophysics ___________ _ 

hydrology __ -------------------------- southeastern, paleobotany _______________ _ 

Idaho batholith, relation between deformation, intrusion, metamorphism, 

metasomatism ______ -- ______ ------

Igneous rocks, post-Cambrian, Appalachian 

Mountains and Gulf Coastal Plain ___ . _________________________ _ 

post-Carboniferous deformation, Massachusetts __ ------ ______ ----------

382 

420 

420 

382 

345 

306 

310 

proposal for clarification of use of names__ 409 

See also particular rock type. 

Illinois-Kentucky mining district, economic geology ___________ . _______ ._______ 294 

geologic map_--------------------------.. 2!!~ 

structural geology________________________ 294 

Illite, association with hot springs_ ---------- 331 

llmenite, chemical method of distinguishing 

from chromite and magnetite_____ 430 

Indian Lakes formation, Carson Desert, Nev_ 329 

Indonesia, central Java, economic geology____ 367 

Intrusions, relation to deformation, metamorphism, and metasomatism____ 345 

relation to ring dikes_____________________ 340 

zoned, magnetic interpretation ___ -------- 387 

Inyan Kara group, Black Hills, South DakotaWyoming __ ---------------------- 349 

Iowa, Fort Dodge, economic geology__________ 410 

Iron deposits, iron-formation, Pakistan_______ 371 

Iron-formation, analyses oL __ -------------- 371,397 

Isostasy, Nevada, Clark CountY--~-~-------- 390 

New Mexico, Sangre de Cristo Mountains_ 391 

Isotopic disequilibrium, asphaltite nodules___ 402 

J 

Jackson group, Jackson dome area, Mississippi___-------------------------- 312 

Jacobina series, Bahia, BraziL________________ 362 

John Day formation, north-central Oregon____ 343 

Jurassic, Arizona, Conconino County_________ 321 

K 

Kansas, Manhattan, geologic map____________ 351 

glacial geology------------------------ 351 

south-central, hydrology__________________ 341 

western, paleontology and stratigraphy--- 352 

Kaolinite, association with hot springs________ 331 

Kentucky, Echo River, hydrology____________ 308 

Mammoth Cave, hydrology______________ 308 

Styx River, hydrology___________________ 308 

Kentucky-Illinois mining district, economic 

geology-------------------------__ 294 

geologic map ___ -------------------------- 294 

structural geology·----------~------------ 294 

L 

La Caja formation, north-central Mexico_____ 369 

La Casita formation, north-central Mexico____ 369 

Lahontan, glacial Lake, stratigraphy_________ 329, 

330, 332, 378 

Lahontan Valley group, Carson Desert, Nev _ 329 

Lake St. Lawrence, effect of flooding, on 

ground water-------~------------- 315 

Lakota formation, new and old members, Black 

Hills, South Dakota-Wyoming___ 349 

Landslides, origin, California ___ "_____________ 323 

Lavras series, Bahia, BraziL------------------ 362 

Lead ores, origin, Wisconsin__________________ 296 

Leonard series, Sierra Madera, Tex___________ 342 

Libya, Tripolitania, hydrology_______________ 422 

Lisburne group, Lisburne. Hills, Alaska_:_-__ 354 
Article 

M 

Magnesium, flame photometric determination ot.-------------------------- 428 

Magnesium and calcium, removal of mBDgancsc from solutions oL_________ 435 

Magnetic surveys, Maine, Chandler Lake 

area. ________ --••• __ -------------_ 387 

Wood Pond area. __ ------------------ 387 

Maryland, Rockville quadrangle_________ 388 

New Mexico, Rio Grande trough_________ 392 

North America, oft' east coast_____________ 396 

Utah, southeast. ..•.. --------. ___ •• ___ .__ 393 

Wisconsin, Drlftless Area_________________ 394 

Magnetite, chemical method of distinguishing 

from chromlto and Ilmenite_______ 430 

Maino, Chandler IJakc area, geophysics._____ 387 

Island Falls quadrangle, geologic map____ 309 

Mount Chase, petrology__________________ 309 

Wood Pond area, geophysics_____________ 387 

Manganese, bicarbonate and sulfate complexes 

In water__________________________ 415 

separation from calcium and magnesium.. 435 

Mangroves, ecology oL---------------------- 365 

Martin formation, Christmas quadrangle, 

Arizona. ___ --------- __ ----------- 397 

Maryland, Rockville quadrangle, geologic 

map ________ -----------------_____ 388 

geophysics ...• _---------- _______ ------ 388 

Massachusctt's, Boston Basin, structural 

gco~ogy ------ --~------ ------------ 310 cast-central, geologic map_________________ 311 

structural geology ___ ----------------- 311 

Mercury, In crude oiL.---------------------- 398 

Mercury limestone, N cvada Test Site, N ev _ _ 328 

Metamorphic rocks, post-Carboniferous deformation, Massachusetts________ 310 

Metamorphism, relation to deformation, intrusion, and metasomatism....... 345 

Motasomatism,contact, In deposition of metallHorous deposits__________________ 356 

relation to deformation; Intrusion, and 

metamorphism___________________ 345 

Mexico, Hidalgo, economic geology___________ 368 

north-central, economic geology___________ 369 

Pachuca mining district, economic 

geology __ •• ----------------------- 3~ 

Parlcutin, geomorphology________________ 370 

M'lca, mineralogy of laminae In sandstone.___ 400 

Michigan, Houghton County, geophysics..... 389 

Middle Lake Lahontan soil, Carson Desert, 

Nov_---•• -------------------_____ 329 

Mineral springs, analyses of gas and water from •••• __ ••• __ ------ ____ ----_____ 353 

origin and movement of water____________ 341 

Mineralogy. &e particular mineral name and 

tmder State names. 

Mlnnewastc limestone member. See Lakota 

formation. 

Mississippi, Jackson dome area, hydrology___ 312 

Mississippian, Alaska, Lisburne Hills________ 354 

Nevada, Nevada Test Site_______________ 328 

Utah, northern___________________________ 335 

Molybdenum, contact-metasomatic deposits, 

Alaska. __ ---~-------------------- 356 

Montana, eastern, paleontology and stratigraphy __ -------------------------- 352 

licbgon Lake, structural geology _______ 346, 347 

Musselshell Valiey, paleobotany__________ 382 

northwestern, paleobotany_______________ 382 

Montmorillonite, association with hot springs. 331 

effect on compaction of sediments_________ 324 

Moon, Lctronne region, Isopach maps.------- 361 

stratigraphy __ --------- __ ----- ___ ----- 361 

Moraines, Rhode _Island, southern____________ 318 

Utah, Little Cottonwood Canyon________ 334 

Mottled structure, In calcium sulfate_________ 410 

INDEX 

Articfe 

N 

Narrow Canyon limestone, Nevada Test Site, Nev _. ______ • _ -- _____ • _ _ _ __ _ _ _ __ __ 328 

Navajo sandstone, Copper Mine-Preston Mesa 

area, Arizona_____________________ 321 

Nebraska, paleontology and stratigraphy____ 352 

Nelchlna limestone, Talkeetna Mountains, 

Alaska. __ ------------------------ 374 

Neoglaclatlon, definition______________________ 334 

Nevada, Antler Peak quandrangle, petrology_ 320 

Buena Vista Valley, geomorphology______ 378 

Carson Desert, glacial geology ______ 329, 330, 332 

Clark County, geologic map______________ 390 

geophysics____________________________ 390 

structural geology_ .. __________________ 390 

Cortez, economic geology_________________ 401 

geochemistry _____________________ .. _ • 401 

Fallon area, glacial geology_____________ 329, 330 

Great Basin, glacial geology______________ 330 

Lake Lahontan, glacial geology _________ 330, 332 

Nevada Test Site, .paleontology and stra- tigraphy_-··----. _______________ 327,328 

southeastern, paleobotany________________ 382 

Steamboat SprinFs, geochemistry_________ 331 

Toiyabe Range, geologic map_____________ 401 

Nevada formation, Nevada Test Site, Nev... 328 

New Hampshire, southern, structural geology_ 311 

New ,Jersey, Wharton Tract, hydrology______ 313 

New .Mexico, Animas Mountains, paleobotany_.------------------------- 382 

Big Hatchet Mountains, paleobotBDY _ _ _ _ 382 

Carlsbad area, geochemistry______________ 402 

Eddy County, mineralogy________________ 403 

Grants, radioactive-waste disposaL______ 421 

Grants-Bluewater valley, geologic map .. _ 421 

Lea County, paleontology and stratigraphy._ ......... ------------------ 338 

Pajarlto Plateau, hydrology_______________ 339 

Rio Grande trough, geologic map_________ 392 

geophysics ___________________________ .. 392 

Sangre de Cristo Mountains, geologic map_ 391 

geophysics ________ .___________________ 391 

structural geology ______________ ._____ 391 

Valles caldera, Jemez Mountains, geolof!;ic 

map ____________________ ---------- 340 

structural geology .. __________________ 340 

New York, Long Island, hydrology___________ 314 

St. Lawrence County, hydrology_________ 315 

Nicaragua, mangrove coasts__________________ 365 

Nickel, in soil formed by weathering of peridotite ..... -------_________________ 404 

North Carolina, northwestern, geologic map__ 316 

Stokes and Surry Counties, structural 

geology ____________ ·-------------- 316 

North Dakota, paleontology and stratigraphy.. 352 

Stutsman County, glacial geology________ 350 

hydrology____________________________ 350 

Notch Peak formation, western Utah._._____ 380 

0 

Oak Spring formation, Nevada Test Site, Nev. 327 

Oakdale quartzite, east-central Massachusetts. 311 

Ohio, Ottawa County, economic geology_____ 410 

011, crude, metals In__________________________ 398 

in relation to uranium deposits _____ . __ __ 295 

Oklahoma, western, hydrology________________ 341 

Open channels. See Surface water. 

Or<iovlcian, Maine., Mount Chase____________ 309 

Wisconsin, Lafayette_____________________ 296 

Oregon, Ashwood, petrology__________________ 343 

stratigraphy __ --------------__________ 343 

Coast Ranges, petrology__________________ 344 

Eight Dollar Mountain, economic geology_ 404 

Nickel Mountain, economic geology______ 404 

Ostracodes, Permian, Texas__________________ 379 

Overvoltage characteristiCs, pyrite crystals.__ 416 

Owens Valley formation, Inyo Range, CaliL 375 

D-405 

Article 

p 

Paiute formation, Carson Desert, Nev._______ 329 

Pakistan, Salt Range, economic geology______ 371 

geologic map.------------------------ 371 

Surghar Range, economic geology________ 371 

geologic map.------------------------ 371 

Paleobotany. See particular plant name and 

under State names. 

Paleontology. &e particular fossil name and 

under State names. 

Paleozoic, Brazil, Bahia______________________ 362 

Florida, Dixie CountY-------------------- 400 

See also particula.r system. 

Pennsylvania, Swatara Creek basin, hydrology---------------------------____ 317 

Pennsylvanian, Nevada, Nevada Test Site... 328 

Utah, northern___________________________ 335 

Peridotite, weathering of. __ --------------____ 404 

Permafrost, Alaska, Yukon-Koyukuk lowland .. ------------------------____ 419 

Greenland, northern______________________ 366 

Permian, California, lnyo Range_____________ 375 · 

Kansas, south-centraL ... ____ --------____ 341 

New Mexico, Eddy County______________ 403 

Texas, Culbertson County_-------------- 379 Sierra Madera •. ______________________ 342 

Utah, northern.__________________________ 335 

Petrofabrics, clay-mineral orientation, sediments undergoing compaction.... 324 

Petrologic classification, proposal for clarification or use of Igneous rock names._ 40\l 

Phosphate deposits, in caves, Indonesia______ 367 

marine, M exlco___________________________ 369 

Phreatophytes, discharge of ground water by__ 37i 

Pierre shale, Great Plains, northern__________ 352 

Pleistocene, Kansas, Manhattan_____________ 31\1 

New Mexico, Valles caldera______________ 340 

VIrginia, Easte~n Shore peninsula________ 381-

See also Quaternary. 

Polygons, In bedrock_________________________ 366 

Portage Lake lava series, Houghton County, 

Micl1 ..•.. --- _ -------------------- 389 

Post-Lake Lahontan soil, Carson Desert, Nev ____________________________ 329, 330 

Potash deposits, in salt anticlines, ColoradoUtah_------------------__________ 337 

Precambrian, Brazil, Bahia __________________ _ 

Utah, Blanding Basin ___________________ _ 

Monument upwarp. ----------------- Wisconsin, Driftless Area ... _____________ _ 

Precipitation, chemical character ____________ _ 

Pre-Lake LahontBD soil, Carson Desert, Nev ... 

Procellarian system, Letronne region, Moon •• 

Pumice, flattening ratios of fragments in ash 

flows .• --------------------------- Purgatoire formation, Cheyenne sandstone 

362 

393 

393 

394 

304 

329 

361 

322 

member, southeastern Colorado._ 414 

Pyrite, overvoltage characteristics of crystals._ 416 

Q 

Quaternary, Alaska, Delta River area________ 357 

Minto Flats__________________________ 383 

Yukon-Koyukuk lowland.----------- 419 

California, Sierra Nevada_________________ 332 

Kansas, Manhattan______________________ 351 

Mont.ana, Hebgen Lake ________________ 346,347 

~evada, Carson Desert _____________ 329,330,332 

Rhode Island, southern------------------- 318 

Utah, Jordan Valley______________________ 336 

Lake Bonneville area _______________ 332,333 

Wasatch Mountains .• ________________ 332 

Wyoming, Firehole Basin quadrangle ... _ 348 

R 

Radiation damage, uranium-bearing usphaltite nodules_______________________ 40;1, 
D-406 

Article 

Radioactive tracers, in measurement of openchannel flow______________________ 425 

Radioactive-waste disposal, in salt deposits... 407 in wells _________________________________ 420,421 

Radio.activation method, determination of 

sensltivitios of trace elements_____ 427 

Radioactivity, association with petroleum____ 295 

Radioactivity surveys, Rockville quadrangle, 

Maryland._______________________ 388 

Rainier Mesa member. See Oak Spring 

formation. 

Radium, in ground water_____________________ 414 

Rare earths, associated with zirconium deposits, B1"aziL____________________ 364 

in Iron-formation, Arizona________________ 397 

Reefs, Cambdan, Utah .. _____________________ 380 

Releasing agents, in flame photometric determinations______________________ 428 

Reservoir storage. See Surface water. 

Rhode Island, southern, glacial geology_______ 318 

Ring ctikes, associated with calderas__________ 340 

related to doming_________________________ 294 

Ripples, regressive, origin____________________ 299 

Roberts Mountains formation, Cortez, Nev _ _ 401 

Roubidoux formation, Kansas-Missouri-Oklahoma_____________________________ 414 

s 

Salooo formation, Eddy County, N.Mex.... 403 

Salt, origin in ground water._________________ 341 

Salt anticlines, potash evaporite cycles in.____ 337 

Salt deposits, removal through solution_______ 341 

Salt-water encroachment, dispersion with 

oscillating flow_._-------.-------- 303 

effect on water levels in wells_____________ 302 

leakage through well casings______________ 386 

San Andres limestone, Grants, ~. Mex _ _ _ _ _ _ 421 

Sand, effective fall diameter and fall velocity_ 300, 

301 

Sandstone, mineralogy of micaceous laminae.. 400 

Scintillation detector, in measurement of open- channel flow _____________ .________ 425 

Seamounts, magnetic profiles_________________ 396 

Sedge, in meadow-pool formation_____________ 355 

Sedimentary facies, influence of domal struc- ture on___________________________ 312 

Sedimentation, effect of temperature__________ 301 

significance nf effective ran diameter and 

fall velocity------. __ .. _ ... ________ 300 

Schoo formation, Carson Desert, Nev ........ 329,330 

Seismology, seismic-electric effect_____________ 395 

Selenium, completeness of precipitation as the 

elr.ment.. __ __ ___ _ _ _ _ _ _ _ ___ _ _ _ _ _ __ 431 

Sensitivities, trace cloments . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 427 

Shatter cones, formed by high-speed impact. 342,417 

Shorelines, Pleistocene, Virginia______________ 381 

Silica, gravimetric determination in chromite 

and chrome ore___________________ 433 

Sills, gabhroic, associated with alkalic rocks.. 344 

Silurian, Nevada, Cortez_____________________ 401 

Silver deposits, Pachuca mining district, 

Hidalgo, Mexico .. ________________ 368 

Sodium, in surface water.____________________ 406 

Sodium-adsorption-ratio diagram, uses of ... _ 422 

Soils, formed by weathering of peridotite .. _ . 404 

moisture distribution_____________________ 339 

Quaternary, California._.---------------- 332 

Nevada.----------------------- 329,330,332 

Utah.--------------------------- ___ 332, 333 

South Dakota, Dlack Hills, stratigraphy______ 349 

paleontology and stratigraphy____________ 352 

Southern Rhodesia, Biklta, geochemistry_____ 413 

Sahi Valley, geologic map_________________ 372 

hydrology_--------------------------- 372 

Sparta sand, Jackson dome area, Mississippi.. 312 

Specific yield, determination of moisture distribution during drainage_________ 434 

Spectrographic methods, determination of 

sensitivities of trace clements.____ 42i 

INDEX 

Article 

Sphene, in granitic gneisses____________________ 399 

Spiritwood buried valley complex, North 

Dakota __________________ --------- 350 

Springs. Se.e Mineral springs, Thermal 

waters. Stade, definition .... ________________________ 333, 334 

Stereoscope, magnifying single-prism, new . 

'instrument for field use___________ 426 

Stockade Wash member. See Oak Spring 

formation. 

Stratigraphy. See particular formation 11ame, 

system name, and under State names. 

· Streambed materials, significance of efl'ective 

fall diameter._____________________ 300 

Streams, western United States, major chemical constituents___________________ 406 

See also Surface water. 

Stromatolites, Cambrian, Utah_______________ 380 

Strontium, flame photometric determination 

of reaction with anhydrite.-------------- 429 

Structural geology. See Deformation, Faults 407 

and Faulting, Folds and Folding, 

Subsidence, and under State name3. 

Subsidence, caldera ____________ .. _____________ 340 

caused by earthquakes _________________ 346,347 

Surface water, acid streams, natural processes 

that dilute and neutralize_________ 317 

California, northern______________________ 325 

chemical constituents, geographic distribution _________ ------------------- 406 

current meter, opticaL___________________ 424 

floods, levee controL_-------------------- 307 

Florida, Dade County____________________ 307 

manganese, bicarbonate and sulfate complexes oL________________________ 415 

new instruments, optical current meter... 424 

New York, Long Island__________________ 314 

open channels, scintillation detect9r in 

measurement of flow ___ ---------- 425 

velocity measurements, method oL·__ 424 

Pennsylvania, Swatara Creek basin______ 317 

regressive ripples, origin__________________ 299 

relation to geology and topography_______ 325 

reservoir storage, for short-period streamflow regulation._----------------- 297 

general solution of a queue modeL____ 298 

temperature variation____________________ 314 

t:!urvey Butte member. See Oak Spring formation. 

Systems, Na20-AhOa-Si02-H20. _____________ 408 

T 

Tallahatta formation, Jackson dome at·ea, 

Mississippi_______________________ 312 

Temperature, water. See Surface water. 

Tempskya, western United St_ates- _______ ~ _ _ _ 382 

Terraces, Pleistocene, Kansas ..... ~----------- 351 

Vir~inia __ --------------------------- _ 381 

Tertiary, Alaska, Minto Flats________________ 383 

California, Funeral Mountains___________ 323 

Colorado, San Juan Mountains___________ 326 

Idaho, Hagerman________________________ 373 

Mississippi, Jackson dome area___________ 312 

Nevada, Humboldt County______________ 373 

~evada Test Site_____________________ 327 

Nye County__________________________ 373 

Oregon, north-centraL____________________ 343 

Utah, Jordan Valley ... ___________________ 336 

Utah County_________________________ 373 

Texas, Culbertson County, paleontology_____ 379 

Karnes County, economic geology________ 295 

northern, hydrology_______________________ 341 

Sierra Madera, geologic map______________ 342 

structural geology. ___ ------~-------__ 342 

Thermal waters, hydrothermal alteration 

associated with. __________ ._ .. ____ 331 

Thorium deposits, associated with zirconium 

deposits, BraziL_________________ 364 

relation to feldspathization, Colorado ... __ · 293 

'l'hule group, Br~nlund Fjord, Greenland____ 366 

Article 

Tiglukpuk formation, Cape Thompson, 

Alaska. ____ ---------------------- 418 

Tippipah limestone, Nevada Test Site, Nev _ _ 328 

Tiva Canyon member. See Oak Spring 

formation. 

Tombador series, Bahia, BraziL______________ 362 

Topopah Spring member. See Oak Spring 

formation. 

Trace elements, sensitivities__________________ 427 

Tracers, hychologic___________________________ 43~ 

Triassic, Arizona, Coconino County__________ 321 

Tritium, as a hydrologic tracer.______________ 432 

Tucumcari shale, Lea County, N. Mex_______ 338 

Tuff, welded, ash, Arizona-Nevada___________ 320 

crystal, Arizona-Nevada_______________ 320. 

moisture distribution, New Mexico... 339 

petrology, Colorado.----------------- 326 

New Mexico_____________________ 340 

Oregon___________________________ 343 

stratigraphy, Nevada_________________ 327 

Turupah formation, Carson Desert, Nev ___ 329,330 

Tymochtee dolomite, Port Clinton, Ohio.____ 410 

u 

United States, central and southern, petrology. 306 

north-central, geochemistry and hydrology _______ .----------------------- 414 

western, paleobotany-------------------- 382 

streams, geochemistry ______ .. _.__ 406 

See also St'Jte n1me11. 

Uranium, in asphaltite nodules_______________ 402 

in phosphatic rock._______________________ 369 

relation to hydrogen sulfide-bearing 

hydrocarbons .... _________________ 295 

Uranium deposits, in oil fields, 'l'exas_________ 295 

Tucano basin, Bahia, BraziL_____________ 363 

Utah, Blanding basin, geophysics .. __________ 393 

House Range, paleontology and stratigraphy _____ · _____ --------------____ 380 

Jordan Valley, glacial geology____________ 333 

hydrology __ ----------------__________ 336 

Lake Bonneville area, glacial geology. __ 332, 333 

Little Cottonwood area, glacial geology. 333, 334 

Monument upwarp, geophysics.--------- 393 

northern, structural geology_ ...... ___ ~___ 335 

Paradox basin, economic geology. __ • _ _ _ _ _ 337 

southeastern, paleobotany________________ 382 

.· Tule Valley, paleontology and stratigraphy ____ ---------------... ------ 380 

Wasatch Mountains, glacial geology ____ 332,333 

v 

Vegetation, influence of seasonal flooding 011.. 365 

tropical coastaL-------------------------- 365 

Vermiculite, interlayered in evaporite________ 403 

Vibratory packer, mechanical method of 

packing porous media .. _.-.-_.____ 305 

Vinini formation, Cortez, Nev._______________ 401 

Virginia, Eastern Shore peninsula, geomorphology __ -----------. _____ ------- 381 

Fredericksburg, hydrology.-------------- 3i9 

Volcanic rocks, flattening ratios of pumice 

fragments __ --~------------------- 322 

:magmatic differences in tuff______________ 320 

Ordovician, Maine •.. ---------------·---" 309 

Quaternary, New Mexico________________ 340 

Tertiary, Colorado _____________________ ~- 326 

Nevada .. _.-----------------------.__ 327 

Oregon. ________________ .... _ ..... -... 343 

See also particular rock type. 

Volcanism, Jemez Mountains, N. Mex______ 340 

San Juan Mountains, Colo 326 

Volcanoes, Kilauea; Hawaii.. ·-------------- 360 

mud, mineral springs associated with..... 353 

Paricut.in, Mexico .. ---------------------- 320 
Article 

w 

Wellington formation, south-central Kansas__ 341 

"Wet" methods, determination of sensitivity 

of trace elements. ____ ------------ 427 

Wilcox group, Jackson dome area, Mississippi_ 312 

Wilkins Peak member. See Green River 

formation. 

Windows, quartzite area, North Carolina____ 316 

Winona sand, Jackson dome area, Mississippi_ 312 

Wisconsin, Lafayette County, economic 

geology___________________________ 296 

Wausau area, geologic map_______________ 394 

geophysics ________________________ --__ 394 

structural geology: ________ ---~--- __ 296, 394 

Article 

Abrahams, J. H., Jr__________________________ 339 

Ali, K. A-8---------·-------------------------- 301 

Allingham, J. W _ -------------------·------ 387,394 

Amezcua, E. T------------------------------- 369 

Anderson, L. A------------------------------- 416 

Andreasen, G. E. __ --------------------"----- 391 

Ash, 8. R---------------------------------- 338,382 

Back, Wiilfam ____________________ ~----------- 423 

Bailey, E. H--------------------------------- 398 

Bailey, R. A--------------------------------- 340 Barker, F. B_________________________________ 414 

Barnes, D. F--------------------------------- 383 

Barton, P. B., Jr ----------------------------- 412 Bates, R. G__________________________________ 394 

Bayley, R. W ---------------------------------- 405 :Seck, H. v___________________________________ 351 

Bell, Henry, III______________________________ 349 

Bergquist, H. R __ ---------------------------- 374 

Black, R. F ---------------------------------- 368 

Brock, M. R------------------------------- ·294,306 

Bryant, Bruce________________________________ 316 

Burbank, W. 8------------------------------- 326 

Campbell, R. H------------------------------ 354 Carlson, J. E.________________________________ 390 

Carroll, DorothY----------------------------- 400 Case, J. E __________________________________ 392,393 

Cederstrom, D.!_____________________________ 422 

Clebsch, Alfred, Jr_ ____________________________ 338 

Cobban, W. A_------------------------------ 352 

Conklin, N. M_______________________________ 399 

Cordell, L. E_________________________________ 392 

Crittenden; M.D., Jr________________________ 335 

Cserna, Zoltan de._-------------------------- 369 

Culbertson, W. C .. -------------------------- 348 

Cuppels, N. P -------------------------------- 310 

Cuttitta, Frank______________________________ 431 

Danilchik, Walter---------------------------- 371 

Davies, W. E._------------------------------ 366 

Dempsey, W. !_______________________________ 396 

Dennis, P. E_________________________________ 372 

Denny, C. 8---------------------------------- 323 

Dinnin, J. L --------------------------- 428-430,433 

Eargle, D. H--------------------------------- 295 

Eaton, J. P ----------------------------------- 360 Eggleton, R. E_______________________________ 342 

Ekren, E. B-------------------------------- 309,385 

Erickson, R. L________________________________ 401 

INDEX 

Article 

Wissahickon formation, Rockville quadrangle, 

Maryland. ____________ ~-----______ 388 

Wood, silicified_______________________________ 382 

Worcester formation, east-central Massachusetts______________________________ 311 

Wyemaha formation, Carson Desert, Nev____ 329 

Wyomin~, Atlantic gold district, economic 

geology___________________________ 405 

geochemistry _____________ ------------ 405 

geologic map_ .. ------------------------ 405 

Black Hills, stratigraphy__________________ 349 

Buffalo area, paleobotany ___ ------------- 382 

Cokeville-Afton region, paleobotany______ 382 

Firehole Basin quadrangle, stratigraphy__ 348 

Powder River Basin, paleontology and 

stratigraphy__________________ 352 

AUTHOR INDEX 

Article 

Feth, J. H ----------------------------------- 304 

Fisher, F. G---------------------------------- 293 

Fosberg, F. R .. ------------------------------ 365 

Fournier, R. 0 ... ---------------------------- 403 

Frederick, B. L------------------------------ 425 

Fries, Carl, Jr._______________________________ 368 

Frischknecht, F. C ... ------------------------ 38.5 

Gault, D. E---------------------------------- 417 

George, J. R-------------------~-------------- 317 

Geyne, A. R--------------------------------- 368 

Gill, J. R ... ---------------------------------- 352 

Godfrey, R. G________________________________ 425 

Goldsmith, Richard__________________________ 399 

Gordon, Mackenzie, Jr _ ---------------------- 375 

Grimaldi, F. S. ___ --------------------------- 427 

Griscom, Andrew---------------------------- 388 

Hamilton, Warren____________________________ 347 

Haushild, W. L______________________________ 300 

Haynes, D. D-------------------------------- 363 

Heath, R. C---------------------------------- 315 

Helz, A. W----------------------------------- 427 

Hem, J. D.----------------------------------- 415 

Remley, J. !_________________________________ 408 

Hendrickson, G. E___________________________ 308 

Herrick, S. M________________________________ 376 

Hey!, A. V., Jr. ____________________________ 294,306 

Hietanen, Anna ____________________________ 345,409 

Hinrichs, E. N ------------------------------- 327 

Hite, R. J ---------·c·------------------------ 337 

Hose, R. K____________________________________ 380 

Hotz, P. E----------------------------------- 404 

Houser, F. N_________________________________ 328 

Hubbell, D. W_______________________________ 301 

Hummel, C. L_______________________________ 356 

Huxel, C. J., Jr.______________________________ 350 

Janes, W. W __ ------------------------------- 405 

Joesting, H. & ______________________________ 392,393 

Johnson, A.!_________________________________ 386 

Johnson, R. F________________________________ 367 

Jones, P. H-------------~--------------------- 420 

Jopling, A. V--------------------------------- 299 

Kachadoorian, Reuben_______________________ 418 

Kane, M. F -------------------------------- 390,391 

Keller, G. V -------------------------------- 389,395 

King, E. R----------------------------------- 396 

Klein, Howard_______________________________ 307 

Klemic, Harry------------------------------- 296 

D-407 

Article 

X 

X-ray diffraction, bikitaite___________________ 413 

clay minerals __ ---------------------------- 403 

mica ________________ ---------------------- 400 

y 

Yeso formation, Grants, N. Mex_ _ _ _ 421 

z 

Zilpha clay, Jackson dome area, Mississippi__ 312 

Zinc, contact-metasomatic deposits, Alaska.__ 356 

Zinc ores, origin, Wisconsin _________________ _ 

Article 

Kohout, F. A-------------------------------- 302 

Krivoy, H. L--------------------------------- 360 

Kulp, W. K .. ------------------------------ 303,305 

Lang, J. W .. --------------------------------- 312 

Lang, S. M___________________________________ 313 

Langbein, W. B ____________________________ 297,298 

Leonard, A. R---------------------"--------- 341 

Lohman, K. E.------------------------------ 373 

Lubke, E. R_________________________________ 359 

Luedke, R. G .. ------------------------------- 326 

Lugn, R. V___________________________________ 417 

McCarren, E. F______________________________ 317 

McClymonds, N. E__________________________ 321 

Marine, I. W__________________________________ 336 

Marranzino, A. p____________________________ 401 

Marshall, C. H_______________________________ 361 

Masursky, Harold ____________ .. ______________ 401 

Matzko, J. J. ___ ------------------------------ 363 

May, Irving ________________________________ 407,431 

Meade, R. H_________________________________ 324 

Merriam, C. W_______________________________ 375 

Mesnier, G. N________________________________ 297 

Meyer, Charles______________________________ 408 

Morris, D. A_________________________________ 305 

Morrison, R. B ___ ---~---------- .-- 329,330,332,333 

Moston, R. P __ ------------------------------ 386 

Myers, w. B--------------------------------- 347 

Nacser, C. R_________________________________ 407 

Nichols, D. R-------------------------------- 353 

Novotny, R. F ---"---------------------- ____ .. 311 

Oda, Uteana .... ___________ _______________ ____ 401 

Oltman, R. E-------------------------------- 297 

Orkild, P. P ---; ___ -------------------------- 327,328 

Peck, D. L___________________________________ 343 

Peck, L.C ________________________ ------- _---- 435 

Peterson, D. L. ___________________ --- -------- 388 

~:~~~o;: ~--~---~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~: !~! Phair, George._------------------------------ Phinney, W. C ___________________________ ---

Pierce, .A. P ___________ ------------- ------~---

Pierson, C. T. _________________________________ _ 

Plouff, Donald. __________ .. ______ -___ ---------

Pluhowski, E. J ______________________________ _ 

Poole, F. G. ---------------------------------

Post, E. V ------------------------------------

Prill, R. C ___ --------------------------------- Purtymun, W. D ____________________________ _ 

293 

413 

402 

362 

384 

314 

328 

349 

434 

339 
D-408 

Article 

Hantz, S. E.................................. 325 

Road, C. B................................... 382 

Hood, J. C., Jr............................... 316 

Hlchardson, E. V............................. 300 

H.lchmond, G. M........... ..•••...•......•.•• 334 

ntchtor, D. H .............................. __ 408 

IUvorn, .T. 0.................................. 369 

Roberson, C. E ..•••••.. --------------------- 406 

Roberts, R. J................................... 320 

Rol:!h.1son, Florence. See Weber, F. R. 

H.ogers, 0. L .. ------------------------------- 369 

Rosholt, J. N., Jr............................. 402 

Ross, C. S.................................... 340 

Schl\for, J. P.. ............................... 318 

Schmidt, R. A. M............................ 358 

Schnopfe, Marian. _________ .................. 407 

Scott, R. C................................... 414 

Segerstrom, Kenneth ____________ -------·-·- 368,370 

Shacklotto, H. T .. ··-·--·-------------------- 355 

Sheffey, N. B................................ 411 

Sherwood, 0. B.............................. 307 

Shoemaker, E. M .......................... 342,417 

.INDEX 

Article 

Slgvaldason, G; E •• -------------------------- 331 

Simons, D. B . .' ... --------------------------- 300 

Sinnott, Allen________________________________ 381 

Smith, R. L---------------------------------- 340 

Smith, V. C .• -------------------------------- 435 

Smith, WinchelL.___________________________ 424 

Snavely, P. D., Jr __________________________ 344,398 

Snyder, G. L ... ------------------------------ 399 

Sohn, I. 0 .... -------------------------------- 379 

Stadnichenko, Taish\_________________________ 411 

Stewart, D. B •• ------------------------------ 413 

Subitzky, Seymour. ....... ------------------- 319 

Sukamto, Rab .......... ---------------------- 367 

Thatcher, L. L------------------------------- 432 

Thayer, T. P ... ------------------------------ 426 

Tibbitts, G. C., Jr. .......... ---------------- 381 

Toulmln, Priestley, 3d.---------------------- 412 

Trainer, F. W ••• ----------------------------- 315 

Vloten, Roger van .... -----------------~------ 369 

Wagner, H. C •• ------------------"·---------- 344 

Wallace, R. E-------------------------------- 378 

Article 

Ward, P. E.·--------~----------------------- 341 

Wark, J. W _. -------------------------------- 317 

Weber, F. R--------------------------------- 419 

Wedow, Helmuth, Jr_________________________ 364 

Weeks, A. D--------------------------------- 295 

Weir, J. E., Jr.------------------------------- 339 · 

West, S. W ----------------------------------- 421 

West, W. S----------------------------------- 296 

White, D. E ... ---------------------------- 331,398 

White, M. G.-------------------------------- 362 

Whitehead, H. C •.• -------------------------- 304 

Willden, Ronald______________________________ 397 

Williams, E. G .. ----------------------------- 430 

Wilson, I. F ---------------------------------- 368 

Withington, C. F---------------------------- 410 

Witkind, I. J.:. ....... ------------------------ 346 

Yehle,. L. A .. -------------------------------- 353 

Zablocki, C. J -------------------------------- 395 

Zietz, Isidore. ______ -------------.-----------_ 396 

Zones, C. P. --------------------------------- 377 

Zubovic, Peter------------------------------- 411 

FINDING LIST OF ARTICLE PAGE NUMBERS 

Article Page .Article Page Article Page Article Page Article Page Article Page3 293 _______________ 1 317--------------- 64 341.. ------------· 150 365. ______________ 216 389.-------------- 272 413 ______________ . a57 

294 _______________ 3 318 ••• ------------ 68 342 ______________ . 151 366.------ --~ ----- 218 390 ............... 274 414 ___ ------------ 35c 

295 ••••• __________ 7 319 _______________ 71 343: .............. 153 367 ............... 219 391_ ______________ 277 415 •... ----------. 362 

296 ............... 9 320 ............... 73 344 ..• --... -...... 156 368 ............... 221 392 .... ----------- 282 416 .• ------------- 365 

297 ............... 12 321. .............. 79 345 ............... 161 369.-------------- 222 393 ............... 287 417 ............... 368 

298 ............... 13 322 ............... 82 346 .............. - 165 370 ............... 225 394 ............... 292 418 ............... 361 

299 ............... 15 323 ............... 85 347 ............... 168 371. .............. 228 395 ............... 296 419 ............... 374 

300 ............... 17 324 ............... 89 348 ............... 170 372 ............... 231 396 ............... 299 420 _______________ 376 

301. ..... _________ 21 325 _______________ 92 349 .............. - 173 373.-------------- 234 397--......... ---- 304 421. .. ------------ 379 

302 ............... 24 326 ............... 94 350 ............... 179 374 ............... 236 398.-------------· 306 422 .............. - 370 

303 ............... 26 327 ............... 96 351. .............. 182 375 ............... 238 399 ............... 310 423 ............... 383 

304 ............... 29 328 ............... 104 352 ............... 185 376 ............... 239 400 ............... 311 424 ............... 385 

305 ............... 31 329 ............... 111 353 ............... 191 377 ............... 240 401. .............. 316 425 ............... 38 

306 ............... 33 330 ............... 115 354 ............... 194 378 ... --------.. -- 242 402 ..• ------------ 320 426 ............... as~ 

307 ............... 36 331. .............. 116 355 ............... 197 379 ............... 244 403 ............... 3:l3 427----- .......... 388 

308 ............... 41 332 ............... 122 356 ............... 198 380 ............... 245 404 ... ·----------- 327 428 ..... -----"~--- 391 

309 ............... 43 333 _______________ 125 357 ............... 200 381. .............. 248 405 ............... 332 429 ............... 392 

310 ............... 46 334 ............... 127 358 ... -... --.. ---- 202 382 ............... 250 406 ............... 334 430 ............... 394 

311 ............... 48 335 ..• --·-........ 128 359 ............... 204 383 ............... 254 407 .. · ............. 336 431. .............. 394 

312 ... ------------ 50 336 •••.•.•.......• 132 360 ............... 205 384 ............... 258 408 ... ------------ 338 432 ............... 396 

313 ............... 52 337 ............... 135 361. .............. 208 385 ............... 259 409 ............... 340 433 ............... 397 

314 ............... 55 338 ............... 139 362 ............... 211 386 ............... 262 410 ............... 342 434 _______________ 399 

315 ............... 58 339 ............... 142 363 ............... 213 387 ............... 265 411. .. ------------ 345 435 .............. - 401 

316 .... ___________ 61 340 ............... 145 364 ............... 214 388 ............... 267 412 ............... 348 

U.S. GOVERNMENT PRINTING OFFICE: 1961 0-604493