l 

~~ 

Short Papers in Geology 

Hydrology, and. Topography 

Articles 120-179 

GEOLOGICAL SURVEY RESEARCH 1962 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 450-D 

Scientific notes and summaries 

of investigations prepared by 

members of the Geologic, Water 

Resources, and Topographic Divisions 

in the fields of geology, hydrology, 

topography, and related sciences 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1962 
UNITED STATES DEPARTMENT OF THE INTERIOR 

STEWART L. UDALL, Secretary 

GEOLOGICAL SURVEY 

Thomas B. Nolan, Director 

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

Washington 25, D.C. 

I I 
.• t 

FOREWORD 

This collection of 60 short papers on subjects in the fields of geology, hydrology, topography, 

and related sciences is the third of a series to be released during the year as chapters of Professional Paper 450. The papers in this chapter report on the scientific and economic results 

of current work by members of the Geologic, Water Resources, and Topographic Divisions 

of the United States Geologicai Survey. Some of the papers announce new discoveries or 

present observations on problems of limited scope; other papers draw conclusions fron1 more 

extensive or continuing investigations that in large part will be discussed in greater detail in 

reports to be published in the future. 

Chapter A of this series, to be published later in the year, will present a synopsis of results 

fron1 a wide range of work done during the present fiscal year. 

THOMAS B. NOLAN, 

Director . 

nr 

' 

CONTENTS 

Foreword·----------------------------------------------------------------------------------------------------

GEOLOGIC STUDIES 

Economic geology 

120. Age of some copper-bearing porphyries and other igneous rocks in southeastern Arizona, by S. C. Creasey and 

Page 

III 

R. W. Kistler_______________________________________________________________________________________ ]) 1 

121. Thalenite from Teller County, Colorado, by J. W. Adams, F. A. Hildebrand, and R. G. Havens__________________ 6 

122. Alteration as a guide to uranium ore, Shirley Basin, Wyoming, by E. N. Harshman____________________________ 8 

123. Alunite on Aspen Mountain, southwestern Wyoming, by J.D. Love and P. D. Blackmon______________________ 11 

124. Clays in the Morrison Formation and their spatial relation to the uranium deposits at Ambrosia Lake, New Mexico, 

by If. C. Granger·---------------------------------------------------------------------------------- 15 

Engineering geology 

125. Geology of Djatiluhur damsite and vicinity, West Java, Indonesia, by H. H. Waldron__________________________ 21 

Stratigraphy 

126. Precambrian(?) and Cambrian stratigraphy in Esmeralda County, Nevada, by J. P. Albers and J. H. Stewart_____ 24 

127. Cambrian Carrara Formation, Bonanza King Formation, and Dunderberg Shale east of Yucca Flat, Nye County, 

Nevada, by Harley Barnes, R. L: Christiansen, and F. M. Byers, Jr______________________________________ 27 

128. Age and sequence of metasedimentary and metavolcanic formations northwest of New Haven, Connecticut, by C. E. 

Fritts---------------------------------------------------------------------------------------------- 32 

129. Age of the Leadville Limestone in the Glenwood Canyon, western Colorado, by W. E. Hallgarth and B. A. L. Skipp_ 37 

130. Type sections for the Morrow Series, of Pennsylvanian age, and adjacent beds, Washington County, Arkansas, by L. G. Henbest _________________________________________________________________________________ R_____ 38 

131. New members of the Bloyd Formation of Pennsylvanian age, Washington County, Arkansas, by L. G. Henbest___ 42 

132. The Eagle Valley Evaporite and its relation to the Minturn and Maroon Formations, northwest Colorado, by T. S. 

Lovering and W. W. Mall<;>ry _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 45 

133. Jurassic stratigraphy in the McCarthy C-5 quadrangle, Alaska, by E. M. MacKevett, Jr., and R. W. Imla;y _____ _ 49 

134. Some Late Cretaceous sttand lines in southern Wyoming, by A. D. Zapp and W. A. Cobban____________________ 52 

135. Tertiary volcanic and related rocks of the Republic area, Ferry County, Washington, by Siegfried Muessig_ _ _ _ _ _ 56 

136. Geology of Tertiary rocks in Escambia and Santa Rosa Counties, western Florida, by 0. T. Marsh______________ 59 

1 37. Stratigraphy and hydrology of the Juana Diaz Formation in the Yauco area, Puerto Rico, by I. G. Grossman_____ 62 

138. Pyroclastic deposits of Recent a.ge at Mount Rainier, Washington, by D. R. Crandell, D. R. Mullineaux, R. D. 

Miller, and Meyer Rubin______________________________________________________________________________ 64 

Structural geology 

139. The Pine Mountain overthrust at the northeast end of the Powell Valley anticline, Virginia, by R. L. Miller______ 69 

140. Gravity and magnetic anomalies in Gem Valley, Caribou Count.y, Idaho, by D. R. Mabey and F. C. Armstrong____ 73 

141. Gravity, volcanism, and crustal deformation in the eastern Snake River Plain, Idaho, by T. R. LaFehr and L. C. 

Pakiser·-------------------------------------------------------------------------------------------- 76 

142. Geohydrologic evidence of a buried fault in,the Erda area, Tooele Valley, Utah, by J. S. Gates__________________ 78 

143. Recurrent movement on the Canyon Creek fault, Navajo County, Arizona, by T. L. Finnell____________________ 80 

144. Restudy of the Arrowhead fault, Muddy Mountains, Nevada, by C. R. LongwelL____________________________ 82 

145. Correlation of granitic plutons across faulted Owens Valley, California, by D. C. Ross________________________ 86 

146. Structural control of interior drainage, southern San Joaquin Vall«"y, Califomia, by G. H. Davis and J. H. Green__ 89 

147. Tertiary salt domes near San Pedro de Atacama, Chile, by R. J. Dingman_~---------------------------------- 92 

148. Zinc occurrence in the Serpent Mound structure of southern Ohio, by "A. V. Heyl and M. R. Brock________________ 95 

Geophysics 

149. Thermoluminescence investigations at Meteor Crater, Arizona, by C. H. Roach, G. R. Johnson, J. G. McGrath, and 

T. S. Sterrett________________________________________________________________________________________ 98 

150. Electrical and magnetic properties of a replacement-type magnetite deposit in San Bernardino County, California, 

by C. J. Zablocki____________________________________________________________________________________ 103 

151. Determination of the magnetic polarity of rock samples in the field, by R. R. Doell and Allan Cox________________ 105 

v 
VI CONTEN'.DS 

Mineralogy, geochemistry, and petrology 

152. Thermal expansion often minerals, by B. J. Skinner_ ______________________________________________________ _ D109 

153. Hydrothermal alteration in drill holes GS-5 and GS-7, Steamboat Springs, Nevada, by G. E. Sigvaldason and D. E. 

VVhite---------------------------------------------------------------------------------------------- 113 

154. Precambrian gabbro in the central Front Range, Colorado, by R. B. Taylor and P. K. Sims _____________________ _ 118 

Geomorphology and glacial geology 

155. Erosional features of snow avalanches, Middle Fork Kings River, California, by G. H. Davis ___________________ _ 122 

156. Configuration of the bedrock beneath the channel of the lower Merrimack River, Massachusetts, by E. A. SammeL _ 125 

157. Geology of Pleistocene deposits of Lake County, Indiana, by J. S. Rosenshein _________________________________ _ 127 

158. Geology of the Vermilion end moraine, Nett Lake Indian Reservation, Minnesota, by R. F. Norvitch _____________ _ 130 

159. Three pre-Bull Lake tills in the Wind River Mountains, VVyoming, by G. M. Richmond _______________________ _ 132 

160. Faulted Pleistocene strata near Jackson, northwestern Wyoming, by J. D. Love and D. W. Taylor_ ______________ _ 13() 

Paleontology and paleoecology 

161. Late Cretaceous Desmoscaphites Range Zone in the western interior region, by W. A. Cobban __________________ _ 140 

162. The ostracode genus Cytherelloidea, a possible indicator of paleotemperature, by I. G. Sohn __________________ _ '144 

Sedimentation 

163. Wind directions in late Paleozoic to middle Mesozoic time on the Colorado Plateau, by F. G. Poole _______________ _ 147 

164. Laboratory studies on deformation in unconsolidated sediment, by E. D. McKee, M.A. Reynolds, and C. H. Baker, Jr ________________________________________________________________________________________________ _ 151 

165. Experiments on intraformational recumbent folds in crossbedded sand, by E. D. McKee, M. A. Reynolds, and C. H. 

Baker, Jr __________________________________________________________________________________________ _ 155 

Illustrative and mapping techniques 

166. Edge isolation in photogrammetry and geologic photography, by A. B. Clarke _________________________________ _ 160 

167. Shortcut method for the preparation of shaded-relief illustrations, by J. R. Stacy _____________________________ _ 165 

HYDROLOGIC STUDIES 

Ground water 

168. VVinter ground-water temperatures along the Mullica River, Wharton Tract, New Jersey, by E. C. Rhodehamel 

and S. M. Lang __________________________________________________________________ ·___________________ 165 

169. Rel:ation of permeability and jointing in crystalline metamorphic rocks near Jonesboro, Georgia, by J. W. Stew~rt_ _ _ 168 

170. Aquifers in buried shore and glaciofluvial deposits along the Gladstone beach of glacial Lake Agassiz near Stephen, 

Minnesota, by R. VV. Maclay and G. R. Schiner________________________________________________________ 170 

171. Potential yield of deep water wells in the southern part of the Jicarilla Apache Indian Reservation and vicinity, 

San Juan Basin, New Mexico, by E. H. Baltz, S. W. West, and S. R. Ash--------~--------------------------- 173 

172. Compaction of the aquifer system and land subsidence in the Santa Clara Valley, California, by J. H. Green______ 175 

.Surface water 

173. Use of short records of runoff to estimate a 25-year average runoff in the Potomac River basin, by W. S. Eisenlohr, Jr_ 178 

174. Use of regionalized flood-frequency curves in adjusting flow-duration curves, by G. A. Kirkpatrick and J. A. McCabe_ 179 

175. A control structure for measuring water discharge and sediment load, by E. V. Richardson and D. D. Harris______ 182 

176. Use of a radioisotope to measure water discharge, by B. J. Frederick, C. W. Reck, and R. W. Carter______________ 185 

Quality of water 

177. Solute degradation in the Potomac River basin, by H. R. Feltz and J. W. Wark_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 186 

178. Foaming characteristics of synthetic-detergent solutions, by C. H. Wayman, J. B. Robertson, and H. G. Page:._____ 188 

179. Surface tension of detergent solutions, by C. H. Wayman, J. B. Robertson, and H. G. Page______________________ 190 

INDE~.ES 

Subject------------------------------------------------------------------------------------------------------- 193 

Author-------------------------------------------------------------------------------------------------------- 195 

f. 
GEOLOGICAL SURVEY RESEARCH 1962 

SHORT PAPERS IN GEOI .. OGY, HYDROLOGY, AND TOPOGRAPHY, ARTICLES 120-179 

GEOLOGIC STUDIES 

ECONOMIC GEOLOGY 

120. AGE OF SOME COPPER-BEARING PORPHYRIES AND OTHER IGNEOUS ROCKS IN SOUTHEASTERN ARIZONA 

By S. C. CRE.\SEY and R.. "'V. ICrsTLER, ~1enlo Park, Calif. 

Dating of the Mesozoic and early Cenozoic geologic 

events in southeastern Arizona is severely hampered 

by the scarcity of fossiliferous sedimentary rocks of 

these ages and by the isolation of individual mountain ranges. Isotopic age determinations, therefore, 

provide definite ages to replace permissive time intervals and aid in the correlation of geologic events from 

one. range to another. 

The IC-Ar and Rb-Sr ages of biotites from some 

intrusive and extrusive rocks in southeastern Arizona 

are listed in table 120.1, and the location of the rocks 

sampled is shown on figure 120.1. Potassium was 

determined by flame photometer using lithium as an 

internal standard. Argon was extracted from the 

specimens using the technique described by Lipson 

(1958). Argon was analyzed with a Reynolds-type 

TABLE 120.1.-Analytical data and isotopic ages of biotites from Arizona 

K-Ar age determinations 

No. on fig. 120.1 Rock Location K (weight 

percent) t 

1 _________ Juniper Flat Granite 2 ________ Northern Mule Mountains, 5. 49 

2--------~ Warren district. 

Intrusive rhyolite ____________ Tombstone district __________ 7. 44 :l _________ Schieffelin Granodiorite ______ _____ do _____________________ 3. 33 4 _________ Equigranular granodiorite ____ Pima district ________________ 7. 28 5 _________ Quartz monzonite porphyry __ _ ____ do _____________________ 5. 98 6 _________ Rhyolite tuff _______ .. ________ _____ do _____________________ 7. 16 7 _________ Andesite dikes ______________ _____ do _____________________ 3. 87 8 _________ Lost Gulch Quartz Monzonite_ Globe-Miami district _________ 7. 24 9 _________ Schultze Granite ____________ _____ do _____________________ 7. 32 10 ________ Vitrophyre (dacite ash flow)~_ _____ do _____________________ 5. 67 lL _______ Granite Mountain Porphyry __ Mineral Creek district _______ 6. 86 12 ________ Quartz diorite porphyry ______ Banner district ______________ 6. 49 13 ________ Copper Creek granodiorite ____ Bunker Hill district __________ 6. 27 

Rb-Sr age determinations 

No. on fig. 120.1 Rock Location RbB7 (ppm) 

1 _________ Juniper Flat Granite 2 ________ Warren district. _____________ 384 _____ do 2 _______ •. ____________ _____ do ____________________ ~ 388 

1 Frank Walthall analyst. 2 Same sample used for Rb-Sr and K-Ar age determinations. 

*Radiogenic. 

Decay constants: 

K40 : ;\.=0.584X10-I0 yr-I, ;\11 =4.72X10-IO yr-I; K40=l.22X10-4 g K4o per g K. 

Rb87 : ;\=1. 47XIO-u yr- 1 ; RbB7=0.283 g RbB7 per g Rb. 

K'OXl0-7 •Ar40X10-11 

(moles per g) (moles per g) 

1.71 171. 0 

2. 32 87.0 

1. 04 44. 6 

2. 27 81. 0 

1. 87 61. 5 

2. 23 74. 7 

1. 21 16. 9 

2. 26 83. 6 

2. 28 77. 7 

l. 77 20. 4 

2. 14 79. 6 

2. 02 73.9 

1. 96 78. 8 

Normal Sr •sra7 (ppm) 

(ppm) 

22. 2 0. 994 

21. 3 1. 017 

Ar'OfK'o Age(m. y.) 

0. 01 163 

. 00375 63 . 00429 72 . 00357 60 . 00329 .56 . 00335 57 . 0014 24 . 0037 62 . 00341 58 . 00115 20 . 00372 63 . 00366 62 . 00402 68 

SrB7/RbB7 Age(m. y.) 

0. 00259 176 . 00262 178 

D1 
D2 GEOLOGICAL SURVEY RESEARCH 19 6 2 

111' 

UO" -i"' I! 

1\ 

-r-~~~~--+=-----l---......:):::~--------+----l----+ll_36' 

•I 

I\ 

•l 35'-Jr--1-----+--~-l----.\-~---+------n-' 35' . 

112' 

3e 2 I 

Nogales __ t-- __ _j 

Ill' 110' 109' 

50 0 50 lOOMILES ~~~L----L---~ 

FIGURE 120.1.-lndex map of Arizona showing location of igneous rocks sampled for the isotopic age determinations 

listed in table 120.1. 

mass spectrometer by the geochronology group of the 

University of California, Berkeley. Rubidium and 

strontium were determined by isotope dilution techniques described by Goldich and others (1961, p. 8-35). 

The analytical determination of potassium and the 

mass spectrometric measurements of Ar, Rb, and Sr 

are accurate to about 2 percent. The probable error of 

an individua:l mineral age is about +4 percent. 

Most of the intrusive rocks are related spatially 

either to ore deposits or to structures. These dates are 

a start toward establishing the age of mineralization 

of the porphyry copper and other deposits. In the 

following, the ages of the igneous rock will be discussed briefly in relation to the ore deposits of four 

general areas, each including one or more mining districts. 

WARREN (BISBEE) AND TOMBSTONE DISTRICTS 

Three intrusive rocks from the Warren and Tombstone districts were dated : The Juniper Flat Granite 

from the northern end of the Mule Mountains, intrusive rhyolite from south of Tombstone, and the Schieffelin Granodiorite from Tombstone. Gilluly (1956, 

p. 55) determined the age of the Juniper Flat Granite 

to be post-Pennsylvanian ( Horquilla Limestone) and 

pre-Lower Cretaceous (Bisbee Group). He also assigned a tentative Tertiary age to the intrusive rhyolite south of Tombstone on indirect geologic evidence 

(Gilluly, 1956, p. 106) and correlated it with the 

granite porphyry mapped by Ransome (1904) in the 

Warren district. The similarity in chemical composition of the intrusive rhyolite and the granite porphyry supports this correlation: both have an unusually high K 2 0 content. This correlation could not 

be tested by isotopic dating, however, for we were not 

able to obtain granite porphyry with fresh biotite. 

Ransome ( 1904, p. 84) thought that the granite porphyry, the Juniper Flat Granite, and the Sacramento 

Porphyry (which is the host for disseminated copper 

ore at Bisbee) were comagmatic. Because the Juniper 

Flat Granite and the granite porphyry apparently had 

supplied pebbles to the basal conglomerate of the 

Bisbee Group of Early Cretaceous age,. he assigned 

the entire rock suite arid the ore deposits to the preLower Cretaceous. Others, however, such as Tenney 

(1935, p. 225-227), believed that the Sacramento Porphyry and the spatially related ore deposits at Bisbee 

are Late Cretaceous or early Tertiary (Laramide) . 

The isotopic dating of the ,Juniper Flat Granite and 

the intrusive rhyolite do not establish the age of the 

Bisbee ore deposits. However, they do support Gilluly's conclusions that both Cenozoic and Mesozoic 

granitic rocks occur in the Bisbee area, that the apparent time interval between them is about 100 m.y. 

(million years), and that the deposits at Bisbee probably are related in time to only one of these. 

Bain ( 1952) , using the PJri>7 /Pb2<J6 ratio of uraninite · from veins in the Bisbee district, suggested that 

the age of the Bisbee ore is 85 to 112 m.y. The radiogenic components of lead in the uraninites were small, 

however, and isotopic analyses of lead in the samples 

were not internally consistent. Under such conditions an unequivocal age determination is most difficult. Our data neither confirm nor contradict Bain's 

determinations. 

The Schieffelin Granodiorite is the rock unit most 

closely related in time and space to the ore deposits 

at Tombstone ( Gilluly, 1956, p. 160). The geologic 

age of the Schieffelin Granodiorite is post-Bronco Volcanics, which rests on the eroded surface of the 

Bisbee Group (Gilluly, 1956, p. 87). The isotopic age 

seems compatible with the position of the Schieffelin 

Granodiorite in the geologic sequence, and, as a working hypothesis, 72 m.y. can be used as the maximum 

age of the ore deposits at Tombstone. 

The Schieffelin Granodiorite is younger than thrust 

faults in the Tombstone Hills. The age of the Schief-
ARTICLE 120 D3 

felin therefore establishes a minimum age of 72 m.y. 

for the thrusts. 

PIMA DISTRICT 

K-Ar ages were determined for four igneous rocks 

from the Pima district: equigranular granodiorite, 

quartz monzonite porphyry, rhyolite tuff, and andesite 

dikes. These rocks and their general relations to each 

other, to the ore deposits, and to the structures in the 

area have been described by Cooper (1960, p. 72, 74, 

76, and 89). 

After a major orogeny that formed highly complex 

northwest-trending fault and fold structures in sedimentary and volcanic rocks of Cretaceous ( ? ) age, the 

granodiorite and quartz monzonite porphyry were 

intruded. Although the geologic evidence is not unequivocal, Cooper (1960, p. 74) thought the granodiorite was older, but he gave no impression of a significant time break between the two intrusives. 

Cooper's views are supported by the K-Ar ages of the 

two rocks. 4-ccording to Cooper (1960, p. 63) the 

quartz monzonite porphyry is spatially associated with 

ore deposits in the Pima district, and possibly is 

genetically related to them. This possible genetic 

relation, however, is indirect because the porphyry itself is the host for the disseminated copper ore. The 

1\:-Ar age of very slightly mineralized porphyry, 56 

m.y., establishes a maximum age for the ore. 

According to Cooper ( 1960), the Helmet Fanglomerate is younger than the ore deposits, and is cut 

by a large thrust (San Xavier thrust) which also is 

younger than the ore deposits. Both the San Xavier 

thrust and the Helmet Fanglomerate are transected 

by a narrow zone of andesite dikes. The K-Ar age 

of the andesite dikes establishes a minimum age for 

the thrusting and ore deposition. 

The K-Ar dates give some information on the apparent ages of structural events in the Pima district. 

Here, thrusts and folds are older than 60 m.y ., the age 

of the granodiorite, whereas in the Tombstone district, 

thrusts are older than 72 m.y., the age of the Schieffelin Granodiorite. A Late Cretaceous-early Tertiary 

period of deformation that includes thrusting long 

has been postulated for southeastern Arizona, and 

these apparent dates help to define it. In addition, 

Cooper (1960) recognized the S:tn Xavier thrust in 

the Pima district as being a distinctly younger and 

independent structure. The age of the andesite dikes 

(24 m.y.) established a significant younger age limit 

for this thrust. Unfortunately a reliable older age 

limit was not obtained. The rhyolite tuff, which is 

older thal'l: the Helmet Fanglomerate, was dated with 

the hope that it, along with the andesite dikes, would 

bracket the Helmet Fanglomerate and San Xavier 

fault within a small time span. The K-Ar age of the 

rhyolite tuff is virtually the same as that of the 

quartz monzonite porphyry, thus the time interval between the apparent maximum and minimum ages for 

the Helmet Fanglomerate and the San Xavier thrust 

is 32 m.y., a figure much larger than we anticipated. 

The similarity of the J(-Ar ages of the quartz monzonite porphyry and rhyolite tuff, however, raises the 

problem of a possible genetic relation between the two. 

The K-Ar ages of the four rocks in the Pima district suggest the following sequence of events: 

. 1. Deformation intensely folded and faulted the 

volcanic and sedimentary rocks over 60 m.y. ago. 

2. The quartz monzonite porphyry was mineralized 

no earlier than 56 m.y. ago. 

3. The deposition of the Helmet Fanglomerate and 

the movement along the San Xavier thrust occurred 

less than 56 to 57 m.y. ago (the K-Ar ages of the 

quartz monzonite porphyry and the rhyolite tuff), and 

more than 24 m.y. ago (the K-Ar ages of the andesite 

dikes). 

GLOBE-MIAMI DISTRICT 

The Lost Gulch Quartz Monzonite and the Schultze 

Granite from the Globe-Miami district were dated by 

the K-Ar method. The Lost Gulch Quartz Monzonite 

is the host rock for the Castle Dome and Copper Cities 

disseminated copper deposits. Locally the Schultze 

Granite is also mineralized. 

· The Lost Gulch Quartz Monzonite is known to be 

post-Paleozoic, but there are no Mesozoic rocks in 

the area by which its age relative to that era can be 

determined. It is cut by granite porphyry that seems 

to be genetically related to the Schultze Granite, and 

on this basis the Schultze Granite was thought by 

Peterson (1954) to be younger. Peterson (1954) 

thought the extensive copper mineralization in the 

Globe-Miami district closely followed the intrusion of 

the Schultze Granite and granite porphyry and was 

the culminating event in the long period of igneous 

activity. The close spatial relation of the Lost Gulch 

Quartz Monzonite and Schultze Granite supports the 

close isotopic ages and, indirectly therefore, the general time of the igneous activity in the Globe-Miami 

district. Until further information on the age of the 

deposits is available, a tentative maximum age of 58 

m.y. for the disseminated copper deposits seems reasonable. 

In the Globe-1\t[iami district, a large ash-flow deposit 

of post-mineralization dacite accumulated on a welldeveloped erosion surface. Here and there as much 

as several hundred ·feet of conglomerate (Whitetail 

Conglomerate) separates the dacite from the under-
D4 GEOLOGICAL SURVEY RESEARCH 1962 

lying rocks. The J{-Ar age of the vitrophyre at the 

base of N1e dacite is 20 m.y. This age for the "cover 

rocks" is a minimum for the copper mineralization 

in the Globe-~1iami district. Secondary enrichment in 

the Miami-Inspiration ore body is related to topography that antedates the 'Vhitetail Conglomerate 

(Ransome, 1919, p. 173-174), which suggests that the 

ore is considerably older than the dacite. 

MINERAL CREEK, BANNER, AND BUNKER HILL 

DISTRICTS 

The Granite ~1ountain Porphyry from Ray (Mineral Creek district) , the quartz diorite porphyry from 

Christmas (Hanner district), and the granodiorite 

from Copper Creek (Bunker Hill district) were dated 

by the 1\::-Ar method. These three districts are separated by about 40 airline miles, Christmas being 

roughly 1!5 airline miles southeast of Ray, and Copper 

Creek toughly 25 airline miles southeast of Christmas 

(fig. 120.1). 

At Ray, the Granite Mountain Porphyry forms part 

of the disseminated copper deposit. At Christmas, 

pyrometasomatic copper deposits formed along the 

intrusive contacts of the quartz diorite porphyry and 

certain carbonate beds in the Paleozoic section, a'nd 

. at Copper Creek, the granodiorite is the host rock 

for perhaps 25 to 50 breccia pipes, many of which are 

mineralized. 

The Granite Mountain Porphyry cuts only the Precambrian Pinal Schist, so that its age relative to 

younger rocks is indeterminate. Both the quartz 

diorite porphyry at Christmas and the granodiorite 

at Copper Creek intrude andesitic volcanic rocks. AccOl·ding to Frank Simons (written communication, 

1962), the andesites intruded by the granodiorite appear to overlie unconformably a sequence of conglomerate and shale that he has correlated tentatively 

with the Pinkard Formation of Late Cretaceous age. 

Holmes ( 1960) dates the end of the Cretaceous at 

70+2 m.y. The isotopic ages of the quartz diorite 

porphyry at Christmas and the granodiorite at Copper Creek do not conflict with their ages as determined by their relation to other rocks, some of which 

have been dated by fossils, and until further information is available 62 and 68 m.y. are reasonable assumptions for the maximum age of the ore deposits 

at Christmas and Copper Creek respectively. 

The 1{-Ar nge of 63 m.y. for the Granite Mountain 

Porphyry is close to that of the quartz diorite porphyry at Christmas, the Schultze Granite, and the 

Lost Gulch Quartz Monzonite. Ransome's (1919, p. 

67) geologic studies indicated a 9lose genetic relation 

between the quartzose granitic rocks in the Globe-

~1iami, Ray, and Christmas areas. A close genetic 

TABLE 120.2.-Apparent maximum and minim1w1. aye of ore deposits in six mining districts in Arizona, based on K-A r aye 

of biotites in associated intrusive rocks 

Minin~ district Rock Maximum Minimur11 age (million a!!,'e (million 

years) years) 

---------------------1·-·-------

Tombstone ____ _ Pima _________ _ 

Globe-Miami __ _ Mineral Creek __ 

Bunker HilL ___ _ 

Banner ________ _ 

Average _______ _ Mean _________ _ 

Range ________ . 

Schieffelin Granodiorite __ _ 

Quartz monzonite porphyry. Schultze Granite _______ _ 

Granite Mountain Porphyry. 

Granodiorite at Copper 

Creek. 

Quartz diorite porphyry 

at Christmas. 

72 -------- 56 24 

58 20 

6:~ - - - - - - - -

68 --------

62 --------

();~ 

()2-6:3 

Hi 

relation implies a. close time relation. On this basis, 

the 1\::-Ar age of the Granite ~1onntain Porphyry is 

compatible with Ransome~s g~ologic interpretations. 

The apparent maximum and minimum age of ore 

deposits in the six mining districts based on the J{-Ar 

age of biotit.es in t.he associated intrusive igneous rocks 

("porphyries") are summarized in table 120.2. The 

significance that one attributes to the ages in the table 

depends on the extent to which one accepts a close 

time and genetic relation bet-ween the "porphyries" 

and the ore. In writing about the deposits at Ray and 

~1iami 43 years ago, Ransome (1919, p. 166) lucidly 

stated the position of those of us who accept a close 

tie, but not a direct one : 

Had no previous study been made of the copper deposits of 

the western United States and were observation restricted to 

one onl~r of the two districts here described, the observer 

might wen inquire whether the association of the ores with 

.granitic or monzonitic porph~rry is merely accidental or is an 

illustration of cause and effect. The present state of our information, however, leaves little room for this doubt. Not 

only at Ray and Miami but at Clifton, Bisbee, and Ajo in 

Arizona, at Ely in Nevada, at Santa Rita in New Mexico, and 

at Bingham in Utah, not to mention occurrences outside of 

this countn', copper ores generally similar to those of Ray 

and l\liami are closely associated with monzonite porphyry 

or with porphyry intermediate in character between monzonite porphyry and granite porphyry. In some of these districts the evidence for an essential genetic relationship between ore and porphyry is plain; in others it is more or less 

equivocal to anyone who permits himself to realize that some 

ores, even ores of copper, may occur in localities where there 

is nothing to suggest any connection between them and igneous activity. Taken collectively, however, the disseminated 

copper deposits of the southwestem United States present convincing evidence that the monzonitic porphyries, by which they 

are iuntriably accomvanied, had ~omething to do with tlwir 

origin. 

It is not to be supposed, however, that the now visible parts 

of these bodies of porphyry contributed in any active way to 
., 

ARTICLE 120 D5 

Ol'e deposition. They, like the neighboring schist, have themselves been nltet·ed by the ore-bearing solutions, and, where 

fnvornbly situated, have been changed into protore just as the 

~<.:hist wus changed undel' similar circumstances. Their significance lies in theit· testimony to the probable presence of 

much larger masses of similar Igneous material below any 

del)ths likely to be reached in mining, and it is from these 

lnr~el' nnd deeper masses, which must have taken far longer 

to solidify nncl cool than the bodies now exposed by natural 

erosion and in the mines, that most of the energy and at least 

n part of the materials were derived to form the protore. 

Following R.ansome's beliefs, the data presented 

here suggest that the range in age of the ore deposits 

is essentially the range in IC-Ar age of the "porphyries," that is, 56 to 72 m.y. On the Holmes (1960) 

time scale, the Cretaceous period ended 70+2 m.y. ago 

and the Eocene 40 m.y. ago. Using th~se terminal 

dates, the ore deposits are early Tertiary, and the 

range in time of 16 m.y. seems small to us. We find 

considerable support in the data for the concept of a 

Larn,mide period of mineralization in southeastern 

Arizona. 

REFERENCES 

Bain, G. W., 1952, The age of the "Lower Cretaceous" from 

Bisbee, Arizona, uraninite: Eeon. Geology, Y. -:17, p. 305-315. 

Cooper, J. R., 1960, Some geologic features of the Pima mining district, Pima County, Arizona: U.S. Geol. Survev 

Bull. 1112-C, p. 63-103. . 

Gilluly, James, 1956, General geology of central Cochise 

County, Arizona: U.S. Geol. Survey Prof. Paper 281, 169 p. 

Goldich, S. S., and others, 1961, The Precambrian geology and 

geochronology of Minnesota: Minnesota Geol. Survey Bull. 

41, 193 p. 

Holmes, Art.hur, 1960, A revised geological time-scale: Edinburgh Geol. Soc. Trans., v. 17, pt. 3, v. 183-2Hl. 

Lipson, .Joseph, 1958, Potassium-argon dating of sedimentat·y 

rocks: Geol. Soc. America Bull., v. 69, no. 2, p. 137-149. 

Peterson, N. P., 1954, Geology of the Globe quadrangle, Arizona: U.S. Geol. Survey Geol. Quad. Map GQ-41. 

Ransome, F. L., 1904, Geology and ore deposits of the Bisbee 

quadrangle, Arizona: U.S. Geol. Survey Prof. Paper 21, 

168 p. 

--- 1919, The copper deposits of Ray and Miami, Arizona: 

U.S. Geol. Survey Prof. Paper 115, 192 p. 

Tenney, J. B., 1935, The copper deposits of Arizona. in Copper resources of the world: Internat. Geol. Gong., 16th, 

Washington 1933, Rept., v. 1, p. 167-235. 
D6 GEOLOGICAL SURVEY RESEAR'CH 19 6 2 

121. THALENITE FROM TELLER COUNTY, COLORADO 

By J."W. ADAMs, FRED A. HILDEBRAND, and R. G. HAVENS, Denver, Colo. 

The yttrium silicate, thalenite, was first described by 

Carl Benedicks ( 1898) from the Oster by pegmatite, 

Dalane, Sweden. Since its original discovery, thalenite has been found at one other locality in Sweden 

(Sjogren, 1906), in several pegmatites in Norway 

(Vogt, 1922; Schetelig, 1931; Bj~rlykke, .1935), and 

two localities in North America. 

The only published report of thalenite in North 

America was in a listing of mineral occurrences in 

Arizona by Galbraith and Brennan (1959, p. 90). 

They mention that the mineral was found at the Guy 

Hazen claims near Boulder Springs in Mohave 

County, but the source of their information was not 

given. Thalenite was tentatively identified by Alan G. 

King, U.S. Geological Survey, 'in material from this 

same group of claims in 1953, but this earlier work 

was not published. The tentative identification was 

confirmed in the course of the present study. 

The second known occurrence of thalenite in North 

America is in pegmatite at the Snowflake feldspar 

mine, approximately 6¥2 miles northwest of Woodland 

Park in Teller County, Colo. Specimens of rock containing rare-earth minerals from this pegmatite were 

submitted to one of the authors by Mr. Roy Monett 

and Mr. Robert Beal of Woodland Park. These 

specimens were found to contain small amounts of 

thalenite. 

The Snowflake feldspar mine was visited in September 1961 for the purpose of locating the position of 

the thalenite in the pegmatite, but the mineral could 

be found only in dump material. The pegmatite is in 

granite of the Pikes Peak batholith of Precambrian 

age. 

The thalenite occurs in rare subhedral to anhedral 

crystals as much as 2 em across. The mineral is found 

in a complex assemblage of perthitic microcline and 

yttrian fluorite, with minor allanite, fergusonite, zircon, xenotime, fluorite, albite-oligoclase, quartz, altered 

biotite, and molybdenite. Thalenite crystals are commonly partly enclosed in allanite, and both minerals 

appear to have been extensively replaced by fluorite. 

Unaltered thalenite is clear and colorless, has a 

vitreous luster, and closely resembles quartz. Most of 

the thalenite from the Snowflake pegmatite, however, 

has a mottled appearance, being partly white or pale 

pink and partly pale yellow to orangish yellow. The 

pale-pink color probably is due to finely dispersed 

hematite. The yellow parts of the crystals effervesce 

weakly with cold hydrochloric acid and represent partial alteration of the thalenite to an unidentified carbonate-bearing phase (strongest interplanar spacings 

are 6.42, 3.21, 3.38, 4.98, 7.31, 4.23, 3.53, 2.11 A). In 

thin section the thalenite crystals are clear, transparent, and highly birefringent, and are veined by 

cloudy, apparently low-birefringent alteration products. Some crystals show marked zoning, accentuated 

by alteration. 

The X-ray powder data for thalenite from the Snowflake pegmatite, Colorado, and from Osterby, Sweden, 

are compared in table 121.1. The Osterby thalenite 

was kindly supplied by Dr. Henrich Neumann, of the 

Mineralogisk-Geologisk Museum, Oslo, Norway. The 

powder data for the Colorado and Osterby minerals 

agree reasonably well with the published X-ray diffraction diagram of the thalenite by Neumann and others 

(1957). 

The optical properties and specific gravity of the 

Colorado thalenite determined from glassy colorless 

fragments are given below: 

Refractive indices (N a): 

a=l.719±0.002 

~= 1. 739 ± 0.002 

')'=1.748±0.002 

2V(-)=67°30" 

Specific gravity (pycnometer)=4.396 

The value for 2 V was determined with ·the universal 

stage by Edward J. Young, U.S. Geological Survey. 

Thalenite is characterized by a distinct absorption 

spectrum. Under the microspectroscope the mineral 

shows a strong erbium absorption band in the green 

region of the spectrum, extending approximately from 

520 to 526 IDJ.L. This feature can be useful in distinguishing thalenite grains from other similar-appearing 

minerals. 

A quantitative spectographic analysis for the rare 

earths and semiquantitative analysis for other elements, together with determination of C02, H20 +, 

and H20- are given in table 121.2. 

The relative percentages of the lanthanide elements 

in the Colorado thalenite are plotted in figure 121.1 

in the form suggested by Semenov and Barinskii 

( 1958) ; their analysis of a Swedish thalenite (probably from Oster by) is also shown in the figure for 

comparison. In the graph, separate curves connect the 

percentage values of elements of even and odd atomic 

number, so arranged that the pairs of lanthanides that 

are adjacent in the periodic table fall on the same 

ordinate line. This type of presentation shows the 
ARTICLE 121 D7 

20 

1-

z 

1&.1 

() 

0: 

1&.1 

0..15 

~ 

fa 

0 

z 

< :I: 

1-

z 10 ~ 

u.. 

o 

z 

0 

~ ;::) 

CD 

0: 5 

t; 

0 

--o--

Thalenite. Colorado 

----·---- Thalenite, Sweden 

I 

I 

\ I 

~r 

I 

I 

INCREASING ATOMIC NUMBER--+ 

FxouuE 121.1.-Percentage distribution of lanthanide elements 

in thalenite from Colorado and Sweden. Upper pair of 

curves: elements of even atomic number. Lower pair: 

elements of odd atomic number. 

general parallelism in distribution between odd-even 

pair members of the lanthanides as they occur in 

minerals. 

The curves for the elements of odd atomic number 

in the two thalenite samples are strikingly similar, 

but marked differences appear between the plots of 

the elements of even atomic number. The Colorado 

thalenite is characterized by dysprosium and neodymium maximums in contrast to the gadolinium 

maximum found in the Swedish sample. Shifts in 

maximums, notably between the elements gadolinium, 

dysprosium, and ytterbium, may be noted by comparing the analyses of individual yttrium· minerals from 

several localities ( Semenov and Barinskii, 1958, table 

1), but modern analyses of thalenite are so few that 

the extent of variability in this mineral is not known. 

The absence or rarity of thalenite in most pegmatite 

areas appears to be due to the preferential deposition 

of yttrium as one or more of a large number of other 

ytJrium minerals, notably xenotime, gadolinite, and 

t.he multiple oxides, or by its incorporation as a 

vicarious constituent in such species as fluorite, garnet, 

or allanite. I~"'rom a study of the thalenite-beari11g 

pegmat.ites of southern Norway, Schetelig (1931, p. 

fil!)) coneluded that in these deposits the formation 

of thnlenite was favored when there was (1} an exTABLE l21.1.-X-ray diffraction powder data for thalenit.e j1·om 

the Snowflake pegmatite, Teller County, Colo., and from Osterby, 

Dalane, Sweden 

Teller County, Colo. Osterby, Sweden Teller County, 

Colo. Ostcrby, Sweden 

d (A) I [2 d (A) I [2 d (A) I [2 d (A)I /2 

6. 3 5 6. 3 1. 658 2 1. 658 

6. 07 4 6.07 1. 645 2 1. 645 

5. 57 2 5. 57 1. 631 5 1. 629 

5. 50 20 5. 50 25 1. 616 4 1. 613 

5. 16 3 5. 16 1. 603 1 ----- 4. 98 1 -- --- 1. 583 .5 ----- 4. 67 .5 -- --- 1. 570 5 1. 568 

4. 44 5 4. 44 1. 558 2 1. 558 

4. 17 4 4. 17 1. 547 2 ----- 3. 95 1 3. 97 1. 523 1 1. 523 

3. 79 25 3. 79 30 1. 510 2 1. 490 

3. 63 5 3. 63 1. 497 .7 ----- 3. 49 4 3. 51 1. 478 2 1. 480 

3. 44 11 3. 44 13 1. 465 2 ----- 3. 31 2 3. 31 1. 455 3 1. 455 

3. 27 18 3. 27 18 1. 445 1 ----- 3. 16 18 3. 16 18 1. 429 .7 ----- 3. 13 11 3. 13 13 1. 425 1 ----- 3. 10 100 3. 10 100 1. 415 .7 1. 414 

3. 05 4 3. 06 1. 408 1 ----- 2. 96 1 2. 97 1. 404 1 ----- 2. 86 6 2. 87 1. 391 .7 1. 391 

2. 81 40 2. 81 35 1. 382 . 7 -- --- 2. 75 30 2. 76 18 1. 370 2 1. 370 

2. 61 2 2. 62 1. 365 1 ----- 2. 57 5 2. 58 11 1. 329 .5 ----- 2. 51 4 2. 51 7 1. 315 2 1. 316 

2. 46 3 2. 47 1. 299 .7 ----- 2. 42 1 2. 44 1. 282 1 -- --- 2. 40 3 2. 41 1. 254 2 1. 255 

2. 37 1 2. 37 1. 236 1 1. 238 

2. 34 3 2. 34 1. 218 1 1. 221 

2. 30 2 2. 30 1. 197 .7 1. 202 

2. 24 30 2. 24 35 1. 179 . 7 1. 185 

2. 21 1 -- --- 1. 169 2 1. 170 

2. 20 1 ----- 1. 160 2 1. 163 

2. 18 9 2. 18 15 1. 152 .7 1. 153 

2. 127 6 2. 122 15 1. 121 2 1. 125 

2. 103 .7 2. 099 1. 102 2 1. 105 

2. 076 .7 -- --- 1. 083 2 1. 086 

2. 053 3 2. 053 1. 072 .7 ----- 2. 027 2 2. 027 1. 058 2 1. 061 

1. 994 3 1. 998 1. 046 .7 1. 051 

1. 977 4 1. 977 1. 0277 1 1. 0301 

1. 953 2 1. 953 1. 0123 1 1. 0145 

1. 922 .7 ----- 1. 0049 .7 1. 0019 

1. 895 3 1. 895 . 9871 1 . 9871 

1.873 7 1. 873 11 . 9685 .7 ------ 1. 859 .7 -- --- . 9609 .7 . 9615 

1. 845 3 1. 845 . 9481 2 . 9493 

1. 817 4 1. 821 . 9422 .7 ------ 1. 797 3 1. 797 . 9343 1 . 9360 

1. 781 2 1. 781 . 9288 1 . 9310 

1. 768 1 1. 762 . 9100 2 . 9120 

1. 746 .7 ----- . 9032 2 . 9070 

1. 740 .7 ---~·- . 8942 1 . 8956 

1. 728 1 1. 725 . 8884 .7 . 8897 

1. 716 4 1. 716 . 8827 .7 . 8840 

1. 704 2 1. 707 . 8743 .5 ------ 1. 681 1 ----- . 8629 1 . 8633 

1. 670 5 1. 672 

1 The diffraction patterns were taken with Dcbye-Scherrcr powder cameras of 

114.59-mm diameter using the Straumanis technique with Cu Ka (Ni filter) radiation, >-=1.5418 A. The cutoff poiht for these cameras is at[} 28 value or approxim!'tely 5°. Measurements were made with a Hilger-Watts film-measuring rule w.1t~ a vernier precision of 0.05 mm. Shrinkage corrections were determined and apphed to each film. There was no measurable a2 resolution or any lines. 2 Intensities were measured with calibrated film strips prepared such that succes- Rivc step exposures are related to each other by a factor of 112. Because the line 

intensities of Swedish thalenite were nearly identical with those of the Colorado 

thalenite, the intensities or only a few of the strongest lines or the Swedish sample were measured. 
D8 GEOLOGICAL SURVEY RESEARCH 19 6 2 

TABLE 121.2.-Spectrographic analyses and GOa and HaO determinations, in percent. Thalenite, Teller County, Colo. 

[Analysts: R. G. Havens, U.S. Geological Survey (spectrographic); Blanche Ingram, 

U.S. Geological Survey (003 and H20)] 

QUANTITATIVE SPECTROGRAPHIC ANALYSES 

y- - - ------ - ---- ----- 32. 6 La___________________ . 31 

Ce_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 1. 2 

Pr ____ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . 42 

N d _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 2. 0 

Sm _____________ :_____ 1. 6 

Eu __________________ <· 01 

Gd __ - _ - ______ - _____ - 2. 8 

Tb _________________ _ ])y _________________ _ 

Flo _________________ _ Er __________________ _ 

Trn __ ~--------------- Yb _________________ _ Lu _________________ _ 

0. 72 

4. 3 

1. 1 

3. 8 

. 59 

4. 4 

. 83 

SEMIQUANTITATIVE SPECTROGRAPHIC ANALYSES 1 2 

SL ____ Major <> 10 percent) Ca _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 2. 0 

Fe___________________ . 15 

Ba __________________ . 015 

Mg, Mn ______________ . 01 

B _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . 002 

AL _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . 07 Be ________________ . ___ . 0007 

IIaO- <0.1 

1 Elements looked for but not detected: K, Ti, P, Ag, As, Au, Hi, Cd, Co, Cr, 

Cu, Ga, Ge, Hf, Hg, In, Mo, Nb, Ni, Pb, Pd, Pt, Re, Sb, Sc, Sn; Sr, Ta, Te, 'l'h, 

Tl, U, V, W, Zn, Zr. 3 Due to interference by rare-earth lines, usual sensitivities did not apply for some elements. 

cess of yttrium over a-vailable niobium, tantalum, 

and titanium for the formation of multiple-oxide 

minerals, and (2) insufficient beryllium to utilize all 

the remaining yttrium as gaclolinite. These favorable 

conditions may prevail in the Snowflake and possibly 

other pegmatites in the Pikes Peak batholith, but during the formation of most of these pegmatites there 

was a general availability of phosphorus and particularly fluorine so that yttrium was wholly utilized as 

xenotime or captured in the fluorite lattice. 

REFERENCES 

Benedicks, Carl, 1898, Thalenit, ein nenes Mineral aus OsteriJy 

in Dalekarlien: Geol. Inst. Univ. Upsala Bull., v. 4, pt. 1, 

p. 1-15. 

BjySrlyl{ke, arald, 1m~;,, 'l'he mineral 1mragene~is and da~~i­

:fication of the granite pegmatites of Iveland, Setesdal, 

southern Norway: Norsk geol. tidsskr., v. 14, p. 211-311. 

Galbraith, F. W., and Brennan, D. J., 1959, Minerals of Arizona, 3d ed.; Univ. Arizona Bull., v. 30, no. 2, 116 p. 

Xeumann, Hem•ich, Sverdruv, Thor, and Saeb0, P. Chr., 1937, 

X-ray powder patterns for mineral identification, III, 

Silicates: Norske Vidensk.-Acad. Oslo., I Mat-Nat Kl., 

no. 6, p. 16. 

Schetelig, Jabok, 1931, Remarks on thalenite from some new 

occurrences in southern Norway: Norsk geol. Tidsskr., 

v. 12, p. 507-519. 

Semenov, E. I., and Barinskii, 1958, The composition characteri&tics of the rare earths in minerals: Geochemistry, 

no. 4, p. 398-419. (A translation of Geokhimiya.) 

Sjogren, Hj., 1906, Thalenit fran Askagens ln'artsbrott i Viirmland: Geol. foren. forh., v. 28, p. 93-i01. 

Yogt, Th., 1922, tjber Thalenit von Hundholmell; Vid. sel!-'k. 

Skr., I. Mat.-nat. Kl. v. 1, p. 19-45. 

122. ALTERATION AS A GUIDE TO URANIUM ORE, SHIRLEY BASIN, WYOMING 

By E. N. l-lARSHl\fAN, Denver, Colo. 

Geologic investigations in the Shirley Basin, 35 

miles south of Casper, Wyo., show that uranium ore is 

directly associated with altered sand. This association is a reliable exploration guide in this area and it 

may prove· to be useful in exploring other areas with 

· similar geologic histories. 

The Shirley Basin contains one of the Nation's 

largest urani urn -ore reserves. The ore bodies are in 

arkosic sands of the 'Vind River Formation of Eocene 

age. The 'Vind River sediments were derived from 

granitic rocks \Y~st and southwest of the area, were 

carried by streams flowing eastward, and were deposited in a basin eroded in rocks of Cretaceous and 

older age. The basin was elongate in a northwesterly 

direction and lay between the Laramie Mountains on 

the northeast ai1d the Shirley Mountains on the southwest. 

The major ore deposits form a well-defined mineral 

belt along the western flank of a prominent ridge on 

the old basin surface. The belt strikes northwestward, 

has a known length of 7 miles, and is as much as 

11j2 miles wide. The position of the belt immediately 

west of the ridge has been related to favorable physical and chemical conditions produced in that area as 

the ridge was gradually buried by sand, silt, and clay 

. of the vVind River Formation (Harshman, 1961). 

1Jraninite, the principal ore mineral, is believed to 

have been deposited from ground water circulating 

through the permeable members of the 'Vind River 

Formation. The age of the deposits is not known. 
ARTICLE 122 D9 

Exploration drilling and m1n1ng operations in the 

mine~al belt have shown that the major Shirley Basin 

ore deposits are intimately related to large elongate 

bodies of greenish-yellow altered sand that are hereafter referred to as tongues. The altered sand has 

been recognized at various points along a 5-mile segment of the mineral belt and is believed to be present 

throughout the length of the belt. Alteration extends 

several thousand feet southward and eastward from 

the ore deposits, but due to paucity of data in non-orebearing areas the configurations and dimensions of the 

altered -sand tongues are not well known. 

Near ore bodies the altered sand ranges from 10 to 

40 feet in thickness and constitutes from 50 to 90 percent of the sandy beds in which it is found. The 

altered-sand tongues appear to thicken as the distance 

from their ends or sides increases. 

The upper and lower surfaces of the altered-sand 

tongues are generally conformable "·ith the regional 

dip of the Wind River Formation. Local sedimentary 

features such as crossbedding have almost no influence 

on the position of the altered-sand tongues and only 

a minor influence on the character of the sharp contacts between altered and unaltered sand. 

Figure 122.1 is a generalized section normal to the 

end of a tongue of altered sand. It illustrates the 

intimate relation of ore and calcite cement to altered 

sand, as well as the character of the contact between 

altered and unaltered sand. An altered-sand tongue 

may terminate in a simple cylindroidal surface or, as 

sho\vn in this figure, the termination may be composed of several irregular lobes. 

Ore is localized principally at the ends or sides of 

altered-sand tongues, although small ore bodies have 

been found along their top and bottom surfaces. 

Where the ends of altered-sand tongues are composed 

of several lobes, ore is concentrated on the convex side 

of each lobe. 

Calcite and hematite also have been concentrated at 

the ends and sides of the altered-sand tongues. Calcite 

occurs at the contact of altered and unaltered sand, in 

ore on the convex side of the contact, and in gray sand 

beyond the outer limits of ore. Hematite, in bands 

and lenticular masses, is found in calcite associated 

Silty clay 

........ ·····. ·:· 

. . . . . . .. :. . . ·. . : .' .: ~ .: :....... .. . . . .. •. . . . ... :. · .. ·.·.·: :. : . . . .. .... . . · ... · ·. " .,. « ... .,. • : 

. . ·.· ::\: .. 

· .. ··. ::.:: Gra~· ~~~i~~r·e:d· ~~n·d·:.· · · · .' . . . . . . ........ : 

. . .. .. ... . 

. . . . . . . . .. . ·. · ... 

0 

.·. ... . . . . 

10 

. . ·. . . . 

.... 

. ... 

20 FEET 

. .. : 

... 

. . . . • ••• .I • 

. ... 

. · .. 

. . · . 

. ·.· . . .. . 

. . . : ..... : :. =.· ··> ~.:: .~. :' . 

. ... 

.... .. . 

. ... . · ... 

FIGURE 122.1.-Generalized section normal to end of altered-sand tongue showing relation of ore and calcite cement to altered 

sand. 
DlO GEOLOGICAL SURVEY RESEARCH 1 9 6 2 

with ore; it is less common in calcite beyond the outer 

margins of ore. 

Studies to determine the differences between altered 

and unaltered sand are in progress. The results of 

these incomplete studies are shown in the table below. 

Color ________ _ 

Heavy 

minerals. 

Clay minerals_ 

Cement ______ _ 

Carbonaceous 

trash. 

AUered sand 

Greenish-yellow _____ -

Pyrite, magnetite, and 

ilmenite, largely 

removed. 

High-iron montmorillonite. 

Little or no calcite 

cement. 

Incoherent and sooty_ 

UnaUered sand 

Gray. 

Pyrite, magnetite, 

and ilmenite present in significant 

amounts. 

Low-iron montmorillonite. 

Considerable calcite 

cement. 

Coherent, vitreous, 

coalified. 

Other differences may be found as the studies are continued, and some of the differences noted above may 

prove to be characteristic only in limited areas of the 

mineral belt. 

The intimate association of the Shirley Basin uranium deposits with large tongues of altered sand 

strongly suggests that the alteration was produced by 

ground water that carried uranium into the lower part 

of the basin, where reducing conditions caused deposition of uraninite. The character of the alteration associated with the ore deposits indicates that the uranium was carried by weakly acid, moderately oxidizing 

solutions. Such solutions are somewhat difficult to reconcile with the geologic environment of the Shirley. 

Basin either now or in the past. 

The intimate association of uranium deposits with 

altered zones of the kind described here may be characteristic of other basins with geologic histories similar 

to that of the Sh-irley Basin. The practical application of this association in ~xploring for uranium deposits is apparent when the large size of an altered 

zone is contrasted with the relatively small size of an 

ore body. 

Alteration of various kinds is recognized to be more 

or less closely related with ore deposits on the Colorado Plateau (Bowers and Shawe, 1961; Fischer, 1942; 

Granger and others, 1961; and others). Sharp and 

others ( 1955) describe ore deposits related to a contact 

between red and drab sandstone in the Powder River 

Basin, Wyo. These descriptions of alteration associated with deposits of "different ages .and of wide 

geographic distribution st~gg~st that alteration of the 

host rocks may be a feature common to most primary 

uranium deposits in sandstone. 

REFERENCES 

Bowers, H. E., and Shawe, D. R., 1961, Heavy minerals as 

guides to uranium-vanadium ore deposits in the Slick 

Rock district, Colorado: U.S. Geol. Survey Bull. 1107-B, 

p. 175-178. 

Fischer, R. P., 1942, Vanadium deposits of Colorado and Utah: 

U.S. Geol. Survey Bull. 936-P, p. 376. 

Granger, H. C., Santos, E. S., Dean, B. G., and Moore, 1!"'. B. 

1961, Sandstone-type uranium deposits at Ambrosia Lake, 

New Mexico--an interim report: Econ. Geology, v. 56, p. 

1193-1194. 

Harshman, E. N., 1961, Paleotopographic control of a uranium 

mineral belt, Shirley Basin, Wyoming: Art. 148 in U.S. 

Geol. Survey Prof. Paper 424-C, p. C4-C6. 

Sharp, W. N., McKeown, If. A., McKay, E. J., and 'Vhite, A.M. 

1955, Geology and uranium deposits of the Pumpkin Buttes 

area, Powder River Basin, Wyoming: U.S. Geol. Survey 

Prof. Paper 300, p. 373. 
ARTICLE 123 Dll 

123. ALUNITE ON ASPEN MOUNTAIN, SOUTHWESTERN WYOMING 

By J.D. LoVE and PAUL D. BLACKMON, Laramie, Wyo., and Denver, Colo. 

A hitherto undescribed alunite [KAla(S04)2(0H)s] 

deposit is present on the south flank of Aspen Mountain, Sweetwater County, Wyo. (fig. 123.1). Eight 

feet of white claystone contains 60 to 90 percent 

alunite. The claystone was first observed in 1957 by 

E. R. Keller, geologist with the Mountain Fuel Supply 

Co., in cuttings from shallow holes drilled during ex-

. ploration ·for oil and gas. Subsequently, a bulldozer 

trench was dug, exposing the claystone where it is less 

than 30 feet below the surface. The present report is 

based on a study of this trench and on reconnaissance 

studies in 1958 and 1960. 

27 

33 

R. 104 W. 

Alunite I 

trench T 

3 

26 

35 

5 _L....-

The writers are indebted to E. R. Keller, of the 

Mountain Fuel Supply Co., and to W. H. Wilson, of 

the Geological Survey of Wyoming, for unpublished 

field observations. Members of the U.S. Geological 

Survey who have contributed pertinent data are W. H. 

Bradley, Charles Milton, M. E. Mrose, Wayne Mountjoy, J. J. Fahey, Harry Rose, and Joseph Dinnin. 

Preliminary identification of the clay minerals was 

made for the Mountain Fuel Supply Co. in 1958 and 

1959 by H. C. Meeves, J. N. Van Sant, and 0. P. 

Sudgen, of the U.S. Bureau of Mines, and J. A. 

vVhelan, of the University of Utah. 

36 

2 

T. 

T. 

17 

N. 

EXPLANATION 

D >-

0:: 

<( 

Bishop(?) Conglomerate JConglomerate overlain by limestone r 0:: 

and white tuffaceous silicified wlsandstone; contains alunite 

Rock Springs Formation 

White to tan sandstone, 

gray shale, and coal 

Blair Formation 

Brown sandstone and gray shale 

Baxter Shale 

Black and gray soft shale 

(/) 

::J 

0 

w 

u 

<( 

Jw 

0:: 

u 

~--------~~----------1-------~~~4-----------~16 

0 

654685 0-62-2 

9 

2 MILES 

N. 

WYOMING 

Area of r'report 

Contact 

"< 

Strike and dip of beds 

-¢-

Dry hole drilled for oil and gas 

0 

Core hole 

FIGURE 123.1.-Generalized geologic map of the Aspen Mountain area. 
D12 GEOLOGICAL SURVEY RESEARCH 1 9 6 2 

STRATIGRAPHY 

The alunite-bearing claystone is in the upper part of 

a 100- to 330-foot-thick sequence of conglomerate, 

sandstone, limestone, and claystone on the south flank 

of Aspen Mountain. The basal unit is a conglomerate 

between 25 and 250 fe~t thick, composed chiefly of 

locally derived angular fragments of Cretaceous sandstone deposited unconformably across folded Cretaceous rocks of the Rock Springs uplift. This conglomerate has been illustrated, described, and called the 

Bishop Conglomerate by Rich ( 1910), Sears ( 1926, pl. 

3; p. 21-22), and Bradley ( 1936, p. 173). However, 

the lack of similarity of this unit with the red quartzite cobble conglomerate typical of the Bishop in areas 

to the south suggests that they are not correlative; the 

conglomerate on Aspen Mountain is therefore called 

Bishop P) in this article (see fig. 123.1). 

Intertonguing with and overlying the basal conglomerate is a variable sequence of limestone, white 

alunite-bearing claystone, soft porous sandstone, and 

conglomerate. The upper part is exposed in the 

alunite trench and the rest was drilled nearby. In the 

southwest part of the Aspen Mountain area lenses of . ' hght-gray dense limestone as much as 75 feet thick 

overlying the basal conglomerate are exposed in an 

area half a mile across (fig. 123.1; also Sears, 1926, 

p. 20-21) . Some contain "bulbs" and laminated structures resembling algal reefs. This variable sequence . ' whiCl: has been warped into a gentle west-trending 

syncline, extends westward from the area shown in 

figure 123.1 for 2 miles to Antelope Butte, where a 

250-foot section is exposed. It is chiefly very tuffac~o~s soft porous sandstone with some gray crystal 

VItric tuff composed of sodic plagioclase biotite 

amphi "b ole, sanidine, sphene, curved colorless ' ' shards 

obsidian, and pumice. The pyroclastic rocks at Ante~ lope Butte may be in some way related to the alunite 

deposit. 

~wo sequences of highly altered strata are present 

along the crest of Aspen Mountain near the "zone of 

silicification" shown on figure 123.1. Both were mapped 

as Bishop Conglomerate by Schultz (1920, pl. 1) and 

Love and others ( 1955) but were called Blair Format~ on (Upper Cretaceous) by Sears (1926, pl. 2). Marine Cretaceous fossils were found in the lower of the 

two units, in a brown and gray silicified sandstone 

that contains secondary chert, at a locality a mile 

north-northeast of the alunite trench. The Cretaceous unit is overlain by several hundred feet of unfossiliferous chalky white tuffaceous siliceous sandstone . ' quartzite, and secondary chert that are believed to be 

of Tertiary age. The Tertiary sandstone contains 

abundant brightly twinned fresh-appearing plagioclase similar to that in the unaltered sandstone on 

Antelope Butte, but not recognized in sandstone of 

the type Blair Formation 10 miles north of Aspen 

Mountain. No basal conglomerate was observed in the 

Tertiary sequence, and the contact relationships are 

poorly exposed. The quartzite in both units resembles 

angular fragments of quartzite in the Bishop ( ~) Conglomerate in the alunite trench. The Tertiary unit 

and Bishop ( ~) Conglomerate are not differentiated on 

figure 123.1. 

Limestone, claystone, sandstone, quartzite, and alunite were sampled for pollen and diatoms, but all 

proved barren. The age of the strata is therefore 

unknown, but at least the conglomeratic portion is 

younger than the post-middle Eocene arching of the 

Rock Springs uplift. The sequences may possibly be 

of Oligocene age (Love, 1960, p. 209), Miocene, or as 

young as Pliocene. 

ALUNITE DEPOSIT 

The alunite deposit is exposed in a bulldozer trench 

40 feet long, 10 feet wide, and 30 feet deep in sec. 26, 

T. 17 N., R. 104 vV., on the south flank of Aspen 

li'IGURE 123.2.-Alunite claystone in bulldozer pit, sec. 26, T. 17 

N., R. 104 W, showing position of samples described in text 

and on figure 123.3. 
ARTICLE 123 D13 

l\1ountain. The alunite-bearing claystone appears to 

be stratified, as are the overlying beds, which dip about 

2° S. The following section was measured with steel 

tape on the east face of the trench (fig. 123.2) : 

'fop o1: section. 

Congloruerate, gmy, with pink mottling, composed of 

unot·iented angular frngments, several inches long, 

of light- and dark-gray and pink dense quartzite in 

a matrix of light-gray soft poorly cemented finegnl ined sandstone that contains essential1y no magnetic grains; sample 20-1 was taken B feet above 

bose -------------------------------------------- 5 

Sandstone, light-gray, fine-grained, soft, porous, poorly 

sorted; soJUe large gray and purplish angular grains 

of quartzite (?) ; persistent bed with 2° S. dip; sample 20-H is representative ------------------------ 1 

Conglomerate, gray, composed of angular unoriented 

quartzite fragments in a greenish sandy and clayey 

matt·ix; lenses of coarse- and fine-grained fragments 4 

Sandstone, sandy siltstone, and claystone, light-gray 

to pale-green, soft, with angular to subrouncled tabular quartzite fragments as much as 1 inch long; 

beds are lenticular; sandstone is porous, fine grained, 

and has few magnetic grains; more clayey and less 

sandy in lower part; base is breccia of gray arigular 

qmutzite fragments in a matrix of pink, white, and 

gt·ny plastic claystone; sample 20-G is from upper 1 

foot; sample. 20-F is from 2 feet above base ______ _ 

Alunite-bearing claystone, snowy-white, with pink, 

lavender, and yellow secondary mottling; hard, 

bloclQ', plastic when wet; finely sandy in upper part 

and almost pure claystone in lower part; near base 

nre small open vugs associated with inclusions of 

pale-greenish translucent soapy-feeling claystone; 

sample 20-E is of top 2 inches; 20-D is 2 feet below 

20-llJ ; 20-C is 2 feet below 20-D ; 20-B is 1.5 feet 

8 

below 20-C; 20-A is 2.5 feet below 20-B ---------- 8 

Total thickness measured ---------------------- 26 

'l~he underlying 4 feet of strata is chiefly alunite but 

has not been analyzed. 

The trench was located at the site of a core hole 

which completely penetrated the Tertiary section. No 

cuttings or electric logs are available, but it was reported that the base of the Bishop ( ~) Conglomerate 

is 301 feet below the alunite claystone and that within 

this interval are several additional white claystone 

beds of uncertain thiekness (E. R. 1(eller, oral communication, 1962) . 

Nine samples, 20-A through 20-I, whose stratigraphic positions are indicated in the measured section, were analysed for grain-size distribution and 

mineral content with results as shown in figure 123.3. 

The mineral content was determined by X-ray diffl'actometer analysis. 

Figure 123.3 shows that the lower part of the section is composed predominantly of fme-grained material grading upward to slightly coarser at the top of 

the alunite claystone (sample E). In samples E and F 

there are small angular chips of feldspar and quartz 

in the matrix ; an abrupt change to very coarse quartzitic material occurs in F. The percentage of sand-size 

quartz and feldspar particles continues to increase upward in the section. 

The mineralogy of the section, showri in figure 123.3, 

is related directly to the grain-size distribution. Sample A, at the bottmn of the section, contains approxiInately 90 percent fine-grained alunite with an intimate mixture of kaolinitic minerals and a trace of 

quartz. A chemical analysis by 'Vayne Mountjoy, of 

the U.S. Geological Survey, of the clay-size fraction 

from sample A indicates approximately 9 percent 1{20 

·and 0.7 percent Na20. The theoretical K 20 content 

of pure alunite is 11.37 percent. As is indicated below, the 1(2 0 content of two total samples is some-· 

what less than that in the clay-size fraction. 

Analysis of total samples A and B is as follows 

(analyst: IIarry Rose; Li2 0 and N a20 by Joseph 

Dinnin, using flame photometer) : 

Sample A Sample B 

Si 02 __________ 8. 0 16.0 

Al20a--------- 32.0 29. 5 

Fe20a----- __ -- 1.5 .4 

MgO __ ------- .5 1.0 

CaO _________ 1 1 

K20 __________ 6. 8 5. 8 

Ti 02 _ - _ - - _ - - - 1 1 

SO a---------- 37. 0 33. 0 

Li20 __ - ______ . 01 . 01 

Na20---- _-- _- . 58 . 49 

----

86. 59 86. 4 

There is probably at least 10 percent water. The 

alkali deficiency of 3 to 4 percent necessary to balance 

the Ab03 as alunite may be accounted for by the 

presence of ammonia. 

Figure 123.3 shows that above the richest alunite 

claystone (sample A), the abundance of kaolinitic 

minerals increases progressively as the alunite decreases, and more quartz appears in the sand fraction. 

Some montmorillonite-mica mixed-layer material and 

sparse feldspar appear in the upper part of the sequence .. 

The paucity of pyrite precludes oxidation of thi~ 

mineral as the source of sulfur in the alunite. The 

alteration to alunite may have been accomplished by 

sulfate-bearing solutions of hydrothermal origin, but 

a source for such mineralizing waters has not been determined. On the other hand, this deposit may have 

originated in a manner somewhat different from that 

of most alunite deposits, because (a) the alunite-bearing claystone appears to be stratified, (b) it is half a 

mile from the area of intensely silicified rocks, (c) no 

igneous rocks are exposed within 20 miles, (d) a test 
D14 GEOLOGICAL SURVEY RESEARCH 1 9 6 2 

Sample Total sample 

I 

H I~~ 

G I 1~1 

F I 1~::1 

E 

D 

c 

8 

A 

0 

Mineral content 

1111111~1· 

111111~1 

.11111~• 

IIIII~· 

••= ••a 

Ill 

PERCENT 

50 

Clay-size materal 

111111~ 

~~~00~11~ 

~~0:~1~ 

l:o~o:~ 

·_ I. 

100 

Grain-size 

distribution 

ROCK (NO SIZE 

ANALYSIS) 

[:}II~ 

PERCENT 

0 50 100 

EXPLANATION 

Alunite Quartz 

D 

Kaolinite Potassium 

-

feldspar 

Halloysite Mica 

Montmorillonite 

Montmorillonite-mica 

Mixed layer 

Sand 

. [ili]ill!ill 

Silt 

Clay 

FIGURE 123.3.-Grain-size distribution and mineral content of total samples and mineral content of clay-size material in 

samples from section exposed in bulldozer trench, south flank of Aspen Mountain. 

drilled for gas to a depth of 3,704 feet in the NE 

corner sec. 34, T. 17 N., R. 104 W. (fig. 123.1} penetrated no igneous rocks, although Cretaceous sandstone 

and shale were reported to be hard and silicified 

throughout the drilled section (E. R. Keller, oral communication, 1962), (e) a core hole drilled about 200 

feet northwest of this well and a mile southwest of the 

alunite trench penetrated 6 feet of white claystone at 

a depth of 145 feet, suggesting that the alunite may 

occur in beds of moderate extent, rather than in the 

more common hydrothermally precipitated "pods." 

The age of the igneous activity in the Leucite Hills, 

20 to 30 miles north of Aspen Mountain, is 1.25 million years or less, hence latest Pliocene (Bradley, 
ARTICLE 124 D15 

1961). If the alunite is related to this episode of 

igneous activity and was deposited as a bed more or 

less contemporaneously with strata here referred to 

the Bishop ( ~) Conglomerate, then this formation 

could be much younger than has been hitherto suspected. 

The purity of the alunite deposit and the unusual 

features of its occurrence indicate the desirability of 

additional surface, subsurface, and laboratory studies 

directed toward determining its age, origin, and economic potential. 

REFERENCES 

Bradley, W. H., 1936, Geomorphology of the north flank of the 

Uinta Mountains: U.S. Geol. Survey Prof. Paper 185-I, 

p. 163-204. 

1961, Geologic map of a part of southwestern Wyoming and adjacent states: U.S. Geol. Survey Misc. Geol. 

Inv. Map I-332. 

Love, J. D., 1960, Cenozoic sedimentation and crustal movement in Wyoming:· Am. Jour. Science, v. 258-A, p. 204-

214. 

Love, J. D., Weitz, J. L., and Hose, R. K., 1955, Geologic map 

of Wyoming: U.S. Geol. Survey. 

Rich, J. L., 1910, The physiography of the Bishop Conglomerate, southwestern Wyoming: Jour. Geol., v. 18, p. 601-

632. 

Schultz, A. R., 1920, Oil possibilities in and around Baxter 

Basin, in the Rock Springs uplift, Sweetwater County, 

Wyoming: U.S. Geol. Survey Bull. 702, 107 p. 

Sears, J. D., 1926, Geology of the Baxter Basin gas field, 

Sweetwater County, Wyoming: U.S. Geol. Survey Bull. 

781, p. 13-27. 

124. CLAYS IN THE MORRISON FORMATION AND THEIR SPATIAL RELATION TO THE URANIUM DEPOSITS 

AT AMBROSIA LAKE, NEW MEXICO 

By HARRY C. GRANGER, Denver, Colo. 

This investigation is a byproduct of studies being 

conducted. on the uranium deposits at Ambrosia Lake, 

N. ~{ex. A prevailing hypothesis regarding the localization of layer and roll-type uranium deposits in 

sandstones proposes that the ore was deposited at an 

interface between two natural solutions of different 

chantcteristics ( Sha we, Archbold, and Simmons, 

1959). If this is so, differences in the type or degree 

of alteration on opposite sides of an ore layer might 

be reflected in the clay-mineral assemblage. \Vhile 

the writer was studying Ambrosia Lake ores, E. N. 

:Harshman (Art. 122) found that both color and claycomposition differences exist on opposite sides of uranium-ore layers in Shirley Basin, Wyo., strengthening 

the conviction that a similar difference might be found 

at Ambrosia Lake. 

All the samples were collected from the Morrison 

Formation, which contains many large uranium deposits in northwestern New Mexico. In this region 

the Morrison Formation consists of three members; 

from the bottom to top these are the Recapture Member, the Westwater Canyon Member, and the Brushy 

Basin Member. The Recapture is primarily a red to 

gray sandy mudstone containing many sandstone 

lenses. The Westwater Canyon is an arkosic to feldspathic sandstone that is red and hematitic throughout 

much of the region except in areas near known uranium deposits, where it is commonly light gray and 

pyritic. The Brushy Basin is a gray to greenish-gray 

mudstone with scattered sandstone lenses. 

In some places sandstones compositionally similar to 

the vVestwater Canyon lie in channels cut in the upper 

part of the Brushy Basin. One of these, the J ackpile 

sandstone of local usage, at Laguna, contains two of 

the largest uranium deposits in the United States. 

The Dakota Sandstone unconformably overlies the 

Morrison Formation, and although not formally divided, the lower part in this area commonly contains 

a preponderance of carbonaceous shales and impure 

coals. The upper part is massive coarse-grained cross.,. 

bedded sandstone. 

The region under consideration is on .the southern 

margin of the San Juan Basin (fig. 124.1) and, with 

local variations, the regional dip is northward. The 

southern margin of deposition of the Morrison corresponds rather closely to the margin of the San Juan 

Basin, and all the members of the Morrison thin and 

wedge out a few miles south of Ambrosia Lake. West 

of Ambrosia Lake near Gallup, however, and, by inference, southwest of Ambrosia Lake where these rocks 

have been removed by ·relatively recent erosion, the 

Morrison was gently truncated on the northern flank 
D16 GEOLOGICAL SURVEY RE.SEAR•CH 1 9 6 2 

I 

I 

UTAH I 

--~------ -~Q~A~----------­ NEW MEXICO 

I • Farmington I 

I-I 

LJ..I 

SAN JUAN 

il 

:>I BASIN 

I 

W~T ilto Park 

il 

g IR~~o~·~··· •.. 0 1 • (.,1- ·.• Ambrosia 

Gallup "' • ·.. • Lake 

, (.,-<> ~O •· •• Prewitt 

I <, (., · .. I 0 . . .-<\..>-1-;- '• Grants 

<I~ ·. ..,, z ::.< •• 1-~ o,~ ·. ~1)1 

~~~ 

.... ___ ... 

I 

•Laguna 

0 t 

() w .J - ,:, a. .J ,:, 

Albuquerque 

• 

0 50 100 MILES 

EXPLANATION 

- ·Reverse fault 

Teeth on upthrown side 

Monocline 

FIGURE 124.1.-Map showing generalized structural setting of 

Ambrosia Lake. (Adapted from Kelley and Clinton, 

1958.) 

of the ancestral Zuni Mountains by pre-Dakota erosion. The Dakota was, therefore, deposited on successively lower members of the Morrison westward 

and southwestward from Ambrosia Lake (fig. 124.2). 

The primary uranium deposits in the Morrison 

Formation at Ambrosia Lake are largely in sandstones 

of the West water Canyon Member and were deposited 

in the undeformed rocks before faulting. They are 

layered ore bodies characterized by an accumulation 

of carbonaceous matter that coats sand grains and fills 

interstices (Granger, Santos, and others, 1961). The 

uraniun1 occurs largely in the form of coffinite intimately associated with the carbonaceous material. 

The carbonaceous material is inferred to be a precipitate of humic acids derived from decaying plant matter either during Morrison or Dakota time. 

Other, later, unoxidized uranium deposits are closely 

associated with the primary deposits at Ambrosia 

Lake. These were created either by renewed introduction of uranium or by redistribution of the primary 

uranium without accompanying concentration of carbon and without apparent change in the clay content of the host rocks. They are later than and are 

partly controlled by faults, and are not further considered in this study. 

Samples were collected by the writer and E. S. 

Santos. They were prepared for X-ray analysis by 

R. S. Roberts. Analysis of the data was the responsibility of the writer, who wa.s greatly helped by consultations with J. C. Hathaway, P. D. Blackmon, and 

J. J. Remley. 

'Videspread samples were taken to test the clay content of sandstones of the Morrison on a regional scale, 

and suites of closely spaced samples were taken to test 

the clay-mineral variation across primary ore layers. 

The sample suites across primary ore layers were 

selected so as to span the ore layer and extend far 

enough into the host rock on either side so that no 

further significant change in composition would be 

likely. 

The samples (see table ) were prepared and the 

clays were identified by X-ray diffraction methods according to the standard procedure followed in the 

laboratories of the U.S. Geological Survey. Thin sections of some of the samples were studied under a 

petrographic miCroscope. 

MONTMORILLONITE 

Montmorillonite is ordinarily the dominant clay 

mineral in the sandstones of the West water Canyon 

l\{ember, where several tens of feet of mudstone of 

the Brushy Basin separates the West water Canyon 

from the Dakota Sandstone. Several samples were 

taken of sandstone of the West water Canyon Member 

well away from uranium deposits and where the Westwater Canyon was covered by mudstones of the Brushy 

Basin at the time of Dakota deposition. The sandstone was red and hematitic in most of these samples, 

although a sample from the upper part of the Westwater Canyon along the eastern margin of Todilto 

Park, approximately 75 miles northwest of Ambrosia 

Lake, consisted of buff, bleached-appearing sandstone. 

The clay fraction in each of these samples consisted 

largely of montmorillonite with various proportions of 

kaolinite. In some samples chlorite and hydrous mica. 

(illite) were present, but in comparatively negligible 

amounts. 

Microscopic studies of thin sections of sandstones 

from the West water Canyon suggest that the montmorillonite appears early in the genesis of the rocks, 

predominantly as a thin skin on sand grains. It is 
ARTICLE 124 D17 

Sample descriptions 

Sample No. 

Member Description Locality 

Field Laboratory 

23 G 61. 

24 G 61 

25 G 61 

33 G 61a 

56 G 61 

59 G 61 

60 G 61 

74 G 61 

75 G 61 

76 G 61 

77 G 61b 

80 G 61b 

91 G 61d 

100 G 61d 

19 G 59a19 G 59i 

22 G 59a22 G 59h 

129 G 61a129 G 61k 

---------- Westwater Canyon __ Sandstone 1 __________________ _ 

---------- _____ do __________________ do ______________________ _ _· ______________ do __________________ dol _____________________ _ 

_______________ do_____________ Mudstone ___________________ _ 

---------- _____ do _____________ Sandstone 1 __________________ _ 

_ _ _ _ _ _ _ _ _ _ Brushy Basin_______ Mudstone ___________________ _ ---------- _____ do __________________ do ______________________ _ 

_______________ do_____________ Jackpile-type sandstone _______ _ 

_ _ _ _ _ _ _ _ _ _ Westwater Canyon_ _ Sandstone ___________________ _ _______________ do ______ ------- _____ do __________ ------------_ _ ------ ________ do_____________ Mudstone ___________________ _ _______________ do ________ ----- _____ do ______________________ _ _______________ do __________________ do ______________________ _ 

_______________ do_____________ Mudstone gall _______________ _ 

271952- _____ do _____________ Sample suite through ore layer 

271960 in sandstone. 271961- _____ do __________________ do ______________________ _ 

271968 2944 79- _____ do __________________ do ______________________ _ 

294489 

Highway 68 southeast of Window Rock, 

Ariz. · 

East edge Todilto Park, N. Mex. 

Hogback 2 miles southeast of Gallup, N. 

Mex. 

First level, Mary # 1 mine, Ambrosia Lake 

8 miles northeast of Gallup, N. Mex. 

M-5 mine, 9 miles north of Prewitt, N. Mex. 

Do. 

Francis mine, 7 miles north of Prewitt, N. 

Mex. 

North of Prewitt, N. Mex. 

12 miles north of Grants, N. Mex. 

Sec. 17 mine, Ambrosia Lake. 

Second level, Mary # 1 mine, Ambrosia Lake. 

Poison Canyon mine, Ambrosia Lake. 

Sec. 30 mine, Ambrosia Lake. 

Sec. 15 mine, Ambrosia Lake. 

Sec. 25 mine, Ambrosia Lake. 

Do. 

1 Westwater Canyon Member Is directly overlain by Dakota Sandstone. The basal Dakota is not appreciably carbonaceous above samples 23 G 61, and 25 G 61, but is 

coni bearing above 56 G 61. 

WEST 

NORTH FLANK 

ZUNI.MOUNTAINS_ - - - - - _____ _ 

--_:--_:---~ -- --K~ -= -~ ~-=-=-~ --= == -~----=Km= ==- ~ =-=-=-= =-=--=-= 

d{ 

~~ C5 

11\) 

!~{ c:l~ !-'~> 

~a 

:::;;;, l~t~~{ " o E ~ ::Sri: 

EXPLANATION 

~ (/) 

Mancos Shale :::::> 

Cl,ays not d6termined 0 

w 

~ u 

< 

~ 

w Dakota Sandstone ~ 

Upper part sandstone; lower part carbo- u nacoous shale and coal. Clays not 

d6tormined 

~ H - Brushy Basin Member 

Montmorillonitic; Jackpile-like sandstone 

(kaolinitic) at top 

Westwater Canyon Member 

Generally montmorillonitic; kaolinitic 

beneath Dakota Sandstone 

~ 

~ 

Recapture Member 

Clays not d6termined 

........._._.._ Uranium-ore layer 

Chloritic 

AMBROSIA LAKE 

DISTRICT 

FIGURE 124.2.-Idealized reconstructed section extending westward from the Ambrosia Lake district. 

EAST 
DIS GEOLOGICAL SURVEY RESEAHCH 19 6 2 

inseparable from the extremely fine hematite stain that 

affects much of the rock. 

The clay fraction from mudstone lenses and mudstone galls included in the Westwater Canyon is almost entirely montmorillonite; the clay that makes up 

the overlying thick mudstones in the Brushy Basin 

Member seems to have a similar composition. Presumably the montmorillonite in each of these mudstones 

and the montmorillonite in the sandstones are genetically related. 

KAOLINITE 

J(aolinite is present in most samples of sandstone 

from the Morrison Formation, but not in the mudstones. It seems to occur in two different forms of 

vastly different ages. 

Almost pure kaolinite in a zone as much as 50 feet 

thick constitutes the clay fraction of sandstones of the 

Morrison in many places where they are directly overlain by the Dakota Sandstone, particularly where the 

basal Dakota contains abundant organic matter. The 

sandstone is almost pure white and consists largely of 

quartz and alkali feldspar grains in a nearly pure 

kaolinite matrix, although some mixed-layer micamontmorillonite is present locally. Opaque iron minerals, mafic minerals~ and plagioclase feldspars are 

missing. 

J. S. Schlee and R. H. Moench ( 1961), L. B. 

Leopold (1943), and others have noted this kaolinitic 

zone in several places along the southern and southwestern margin of the San Juan Basin. They have 

observed that kaolinite-rich rocks directly underlie the 

erosion surface on which the Dakota rests, and have 

suggested that the kaolinite is a result of weathering 

and soil-forming processes in a humid climate before 

Dakota deposition. Their -data do not permit a comparison between abundance of organic matter in the 

basal Dakota and occurrence of the kaolinite-rich zone. 

Sandstones of the West water Canyon Member are 

red rather than being bleached nearly white, along 

Highway 68 southeast of. Window Rock, Ariz.;-where 

the Dakota directly overlies the West water Canyon. 

A sample collected here contained montmorillonite and 

a greater proportion of k~olinite than is ordinarily 

present in the red sandstones of the Westwater Canyon. The basal Dakota at this locality, however, seems 

to be free of organic matter that may have caused 

bleaching and development of the abundant kaolinite 

found in the white sandstone. 

Kaolinite is present in most samples of Morrison 

Sandstone even where several tens of feet of mudstones 

of the Brushy Basin separates the sandstone from the 

Dakota Formation. This kaolinite, however, forms 

scattered "nests" (J. A. Knox and ·J. W. Gruner, 

1957) or aggregates as much as Y2 inch across that 

completely fill the interstices among the sand grains 

and cause the rock to be splotched with white spots. 

The larger nests occur in coarser grained sandstones. 

There seems to be no evidence that these kaolinite 

nests were derived locally by alteration of aluminous 

silicate minerals, nor is there yet any adequate evidence to link this kaolinite with the kaolinite produced 

in the sandstones directly below the Dakota. The 

available data suggest that this kaolinite is later than 

the faults that were formed long after deposition of 

the sedimentary sequence. 

CHLORITE 

Analyses of the clay-size fractions from suites of 

samples taken across primary ore layers disclosed 

that there is a rough correlation among the uranium, 

organic carbon, magnesium, and chlorite concentrations (fig. 124.3). There is evidence that as the uranium content rises the chlorite content also rises and 

the montmorillonite content diminishes. For purposes of comparison, therefore, the samples were 

heated to 400°C for lj2 hour and a ratio was derived 

from the heights of the resulting X-ray diffractometer 

patterns of the clays. The X-ray diffractometer peak 

height for chlorite (20 =6.2°) was related to the sum 

of the same chlorite peak height ( =6.2°) plus the col-

. lapsed montmorillonite peak height at 20 =8.6 o. This 

ratio was then expressed as a percentage and plotted 

as shown on figure 124.3. The graphs strongly suggest that montmorillonite may have been converted to 

chlorite within the primary ore layers. 

Chlorite also occurs sparingly in some of the samples 

of sandstone collected a way from ore, but its content 

is generally insignificant. 

CONCLUSIONS 

Evidence obtained from X-ray anaJyses, field observations, and examination of thin sections suggests 

that montmorillonite is the earliest clay mineral in the 

Morrison Formation. Where sandstones in the Morrison are overlain by a pre-Dakota erosion surface, 

the montmorillonite and certain other minerals are 

commonly displaced or replaced by kaolinite. Within 

primary ore layers, chlorite has developed, evidently 

at the expense of the montmorillonite. The paragenetic relationship between chlorite and the kaolinite 

noted above is not known. 

The kaolinite that forms white nests in the Morrison 

sandstones in so many places seems to be much later 

than any of the above minerals. It occupies interstices 

in the ore layers and elsewhere. Wherever it is seen, 

it overlies the montmorillonite and chlorite that form 
1-

UJ 

UJ 

LL. 

...... 

C\i 

I 

01 

U') 

" 

~ 

~ UJ UJ LL. 

!:: o:t 

:::J I en 01 

U') 

UJ 

..J " N 

Q.. N 

~ 

c( 

en 

LL. 

0 

:I: 

.... 

0 

§ 

0 

z 

c( 

a: 

UJ 

m 

~ 

:::J 

z 

a I 

cil 

gh 

il 

aJ: 

b 

c 

d 

e 

g 

hl 

c 

d 

e 

g 

h 

i I 

ARTICLE 124 

. 

~Mg 

--------------~~~~~-----

===~========--~-:-:~.:~-+--- : / : / ;.../ 

/; 

/• 

., . SEC. 15 MINE 

0.01 

I 

r 

I 

/ 

' . ' ' c', lMg ' . ~-I 

I 

/ : 

' I 

I 

I 

..... 

/ 

( 

I 

I 

I 

• 

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

/ 

/ 

/ , 

--....... 

/ 

-~ / / /c 

SEC. 15 MINE 

cl--~.:._...:..·....__ .. ,..._ 

........... 

.... --...... - / 

/ 

/ 

: " : ' ' ) 

/ 

/ 

... l 

···\ \"·· .. 

___ --A :::.- .......... .-

: SEC. 25 MINE 

1 •. · 

0.1 1.0 

PERCENT 

D19 

Chi 

Chi+Mont 

Chi 

Chi+Mont 

10.0 100.0 

l!"'IGUIUD 1.24.3-Correlation between concentrations of chlorite, magnesium (Mg), uranium (U), and carbon (C) across ore layers. 

Chi, chlorite; Mont, montmorillonite 
D20 GEOLOGICAL SURVEY RESEAHCH 19 6 2 

thin coatings on the sand grains. It is not known if 

the kaolinite nests are related to the kaolinite that 

underlies the pre-Dakota erosion surface, but certainly 

the nests seem to be much later. 

Montmorillonite is believed to be the normal clay 

component in all parts of the Morrison Formation 

along the southern margin of the San Juan Basin in 

N e\v Mexico. It seems very likely that the montmorillonite, both in the sandstones and the mudstones of 

the l\{orrison~ was derived from alteration of volcanic 

ash that was incorporated in the sediments (Waters 

and Granger, 1953). In some places, before Dakota 

deposition, sandstones in the Morrison were exposed at 

an erosion surface on which the Dakota was later deposited. It may be that this surface represents a moist 

soil-building cycle, and that kaolinite was formed near 

the erosion surface by weathering of feldspars. Possibly, the formation of kaolinite beneath this surface 

is related to soil building as a result of humic-acid 

solutions draining from the boggy, organic-rich terrain on which the basal coals and carbonaceous shale 

beds of the Dakota were deposited. Whatever ·the 

cause, the fact that this intensive alteration and leaching might, in some way, be related to the genesis of 

the uranium deposits should not be overlooked. 

vVithin the primary uranium-ore layers, which also 

contain concentrations of organic carbon; magnesium, 

and various· metallic elements, the normal montmorillonite seems to give way to chlorite. Very likely the 

anomalous magnesium is contained in the chlorite. 

It is not known whether the chlorite was formed 

during the period of uranium mineralization or 

whether it represents a slow progressive alteration of 

the mmitmorillonite under chemical conditions imposed, in part, by the organic material during the ages 

subsequent to mineralization. 

REFERENCES 

Granger, H. C., Santos, E. S., and others, 1961, Sandstonetype uranium deposits at Ambrosia Lake, New Mexicoan ~nterim report: Econ. Geology, v. 56, p. 1179-1210. 

Kelley, V. C., and Clinton, N. J., 1958, Fracture systems and 

tectonic elements of the Colorado Plateau: U.S. Atomic 

Energy Comm. RME-108, issued by the U.S. Atomic 

Energy Comm., Office of Tech. lnf. Extension, Oak Ridge, 

Tenn .. 

Knox, J. A., and Gruner, J. W., 1957, Mineralogy of the Ambrosia Lake uranium deposits in McKinley County, New 

Mexico, in Annual report for Apr. 1, 1956 to Mar. 31, 

1957: U.S. Atomic Energy Comm. RME-3148, issued by 

the U.S. Atomic Energy Comm., Office of Tech. Inf. Extension, Oak Ridge, Tenn. 

Leopold, L. B., 1943, Climatic character of the interval between the Jurassic and Cretaceous in New Mexico andArizona: Jour. Geology, v. 51, no. 1, p. 56-62. 

Schlee, J. S., and Moench, R. H., 1961, Properties and genesis 

of "Jackpile" sandstone, Laguna, New Mexico, in Peterson, J. A., and Osmond, J. C., eds., Geometry of sandstone 

bodies, a symposium: Am. Assoc. Petroleum Geologists, 

240 p. 

Shawe, D. R., Archbold, N. L., and Simmons, G. C., 1959, 

Geology and uranium-vanadium deposits of the Slick Rock 

district, San Miguel and Dolores Counties, Colorado : 

Econ. Geology, v. 54, p. 395-415. 

Waters, A. C., and Granger, H. C., 1953, Volcanic debris in 

uraniferous sandstones, and its possible bearing on the 

origin and precipitation of uranium: U.S. Geol. Survey 

Circ. 224. 
ARTICLE 125 D21 

ENGINEERING GEOLOGY 

125. GEOLOGY OF DJATILUHUR DAMSITE AND VICINITY, WEST JAVA, INDONESIA 

By IIowARD H. 'VALDRON, Ba.ndung, Indonesia 

lVorJ.; douo in coopcra.t·ion with the Gcolortical t:;urvc11 of Indrme:~lia 

Djatiluhur is the site of the first major multipurpose dam to be constructed in Indonesia. Completion 

of the dam, now under construction, will provide 

water for increased irrigation and for additional electrical power, both vitally needed for this densely 

populated part of Indonesia. This investigation was 

undertaken as part of a cooperative program between 

the U.S. Geological Survey· and the Geological Survey 

of Indonesia, under the auspices of the International 

Cooperation Administration. 

The dam is to be a zoned, rockfill structure with a 

sloping impervious core. "Then completed the dam 

will have a height of about 100 meters, a crest length 

of about 1,125 meters, and a maximum width at the 

bn.se of about 575 meters. Total volume of the structure, including cofferdams, will be in excess of 10 million cubic meters. A giant hollow reinforced concrete tower, 90 meters in diameter and 110 meters in 

height, will be embedded in the upstream face of the 

dam to serve as a glory-hole type spillway, provide 

for turbine and irrigation intakes, and house all of 

the power-generating equipment. 

Djatiluhur lies in the "Bogor Zone" (Bemmelen, 

1949, p. 645), a complex belt of hills and mountains 

that form the southern border of the coastal or lowland plain of West Java (fig. 125.1). This zone consists principally of folded and faulted young Tertiary 

marine sedimentary rocks intruded by many igneous 

masses (Ludwig, 1933). The damsite is located in a 

gorge of the Tjitarum River where it cuts through a 

ridge of folded sedimentary strata. Relief ranges 

from 25 meters to about 200 meters near the damsite; 

0 100 200 300 KILOMETERS 

FIGURE 125.1.-Index map showing locution of Djatiluhur dam 

site in West Java. 

elevations are higher south of the damsite, principally 

on the.hills and ridges that are underlain by igneous· 

rocks. 

The rocks of the Djatiluhur area range in age from 

late Tertiary through Quaternary; rocks older than 

Miocene do not crop out in this part of West Java. 

~tfost of the area is underlain by Tertiary sedimentary 

rocks, chiefly marine shale and siltstone but with some 

fine-grained sa.n_cl.stone and a few strata of limestone 

interbedded with the shale. Several thousand meters 

of marine sedimentary rocks accumulated, after which 

deposition ceased and the rocks were folded, faulted, 

and intruded by a variety of intermediate and basic 

igneous rocks during latest Tertiary time. Subsequently the rocks were deeply eroded and partly buried 

by Quaternary alluvial sedimentary deposits. General 

geology of the damsite is shown in figure 125.2. 

Fine-grained facies of sedimentary rocks prevail in 

the area. Silty shale and siltstone predominate, but 

some clay shale and claystone also occur. For the 

most part the rocks are dark gray or bluish to greenish 

gray where fresh, but commonly they are various 

shades of brown where oxidized or weathered. Most 

are calcareous and fossiliferous ; microfossils are very 

numerous, and invertebrate macrofossils also are found 

in some of the strata. The sandstone beds are predominantly fine grained and range in composition 

from light-colored quartzose sandstone to dark-colored graywacke sandstone. Many are calcareous, and 

most are fossiliferous. The rocks range in grain size 

and composition fron1 quartzose through limy sandstone to sandy limestone, or in some places to nearly 

pure limestone ; and from quartzose sandstone through 

siltstone to silty shale. A few of the rocks are tuffaceous, and some are glauconitic. The lenses and 

beds of limestone are mostly a fossiliferous-fragmental 

limestone that consists of fossil fragments cemented 

in a matrix of crystalline limstone and grains of sand, I 

silt, and clay. Most strata are well sorted; stratification ranges from well bedded to obscurely bedded or 

massive. Argillaceous rocks are commonly fissile or 

shaly but may range from laminated ·to massive claystone. 
D22 

A METERS 

100 

50 

0 

9 8 7 

100 

6 

GEOLOGICAL SURVEY RESEARCH 1 9 6 2 

CONTOUR INTERVAL 10-METERS 

EXPLANATION 

Sandstone 

~ 

~ 

Shale 

1 

Shale and sandstone 1 

5 

200 0 

>-

0:: 

<( 

to:: 

LLJ 

t-

.ll' ~ }' ~LLJ ..... a:: ~ Some shale and 

limestone 

Contact 

Dashed where approximately 

located; dotted where 

concealed 

Axis of dam 

4 

200 400 METERS 

N 

1 

GEOLOGY BY H. H. WALDRON, 1960 

Inferred contact 

ts2 

Strike and dip 

of beds 

Limits 

~ 

of dam 

LITHOLOGY FOR SECTION 

[IT] 

Sandstone 

D 

FIGURE 125.2.-Generalized geologic map and section of Djatiluhur damsite, West Java. 
ARTICLE 125 D23 

A variety of igneous rocks have intruded the Tertiary sedimentary rocks. Most of these are intermediate, or intermediate to basic in compositionhornblende andesite, augite andesite, alkalic basalt, 

hornblende diorite porphyry, and so forth. l\1ost of 

the rocks are light gray and contain prominent phenocrysts of feldspars and mafic minerals in a finegrained matrix. Solid rock is .rarely exposed; most 

of the hills are nea1·ly completely mantled with large 

blocks and boulders of igneous rock in a clayey matrix 

of altered ash. '¥here exposed, the igneous rocks 

range in structure from columnar to massive; many 

are plnty. Loeally, near the intrusive masses, the shale 

and siltstone have been altered by heat and pressure 

into low-grade metamorphic roeks sueh as· argillite 

and hornfels. 

All the Tertiary sedimentary rocks were folded and 

faulted, probably during Plioeene time. Structural 

details are difficult to interpret due to. limited exposures and the lack of marker beds, but the major 

structure of the area consists of the south limb of a 

large anticline or anticlinorium, the north limb of 

which is absent due to faulting. The strata dip southward, almost homoclinally, but some minor gentle 

folds occur on the flank of the major anticline (fig. 

125.2). In general, dips are low, 15°-20°, but locally 

they may be as high as 80° .. A major fault displaces 

the older strata both north and east of the damsite. 

Ludwig ( 1933) mapped this feature as a large thrust 

fault on the basis of evidence farther east, although 

evidence within the mapped area indicates that it is 

a normal high-angle fault at least locally, the relative 

movement of which has been downward to the north 

and east. Other smaller normal faults are present, 

but none were observed to underlie the foundation of 

the dam. Minor adjustment to deformation, however, 

is represented throughout the area by numerous joints 

and by small displacements of less than 1 to 2 meters. 

Grouting of the jointed sandstone and limestone will 

be necessary in places to assure adequate control of 

seepage. 

Uncomformably overlying the Tertiary strata are 

alluvial and lahar deposits of very late Pliocene or 

early Pleistocene age. These deposits normally consist 

of coarse volcanic sand and pebble-cobble alluvial 

gravel at the base, overlain disconformably by a lahar 

deposit of varying thickness. The lahar deposit is 

an unsorted, compact mixture of volcanic sand and 

gravel, including. large boulders, in a n1atrix of silt 

and clay. In upland areas, the lahar is deeply 

weathered to a red lateritic soil; at depth, however, 

it is relatively fresh and gray. l\1aximum thickness 

of the lahar is more than 75 meters. Younger Quaternary deposits inclu<;le late Pleistocene terrace deposits 

in the Tjitarum· valley, and modern alluvium underlying the valley bottoms and flood plains of the 

Tjitarum River and its tributaries. The terrace deposits eonsist of moderately weathered alluvial sand 

and gravel, some overbank deposits of lacustrine silt 

and clay, and the reinnants of at least one thin lahar 

deposit. Maximum thickness of these deposits is 

about 35 to 40 meters. 

The engineering characteristics and physical properties of the various rocks and soils in the Djatiluhur 

area are not "·ell known, but preliminary observations 

and tests by the author and others, and soil tests being 

made by the engineering consulting firm of Coyne 

and Bellier, of Paris, Franee, indicate that the rocks 

at the proposed site are favorable for the support of 

heavy structures, and that the rocks and soils comprising the walls of the reservoir are favorable for 

containment of impounded waters. Numerous geologic factors were of prime importance in determining 

the final design of the dam. Some of these are (1) ~he 

difficulties inherent in the construction of a concrete 

dam on a predominantly shale foundation, (2) potential seismicity of the area, ( 3) lack of nearby adequate 

sources of materials of construction for either a conerete or an earth-fill structure, and ( 4) adequate 

nearby source of sound igneous rock suitable for construction of a rock-fill structure. 

REFERENCES 

Bemmelen, R. W. van, 1949, The geology of Indonesia, v. lA, 

General geology of Indonesia and adjacent archipe1agoes: 

The Hague, GoYernment Printing Office, Indonesia Bur. of 

Mines Spe('. Ed., 732 p. 

Ludwig, 0., 1933, Toelichting bij Blad. 30 (Poewakarta) : 

Geological mnv of Indonesia, 1 :100,000, Dien::;t :\linjb. Ned. 

Ind., 45 p. 
D24 GEOLOGICAL SURVEY RE,SEABCH 19 6 2 

STRATIGRAPHY 

126. PRECAMBRIAN(?) AND. CAMBRIAN STRATIGRAPHY IN ESMERALDA COUNTY, NEVADA 

By J.P. ALBERS a.nd J. H. STEWART, Menlo Park, Calif. 

Work d01·w in coope1·ation tdth the Nevada- Bu1·eau of lllines 

In 1960 the U.S. Geological Survey began a study 

of Esmeralda County, Nev., as a part of a program 

of county mapping done in cooperation with the 

Nevada -Bureau of Mines. By the end of the 1961 

field season most of the exposed Precambrian ( ~) and 

Cambrian rocks had been mapped and the stratigraphic 

section largely worked out. The purpose of this paper 

is to record the pertinent stratigraphic information. 

In gross aspect, the section closely resembles that 

recently described by Nelson (1962, p. 139-144) in 

the White and Inyo Mountains, Calif., and the names 

used by Nelson for Lower Cambrian and underlying 

rocks are applied in Esmeralda County. We are indebted to Nelson' for showing us part of the section 

in the field during 1960, and also to E. H. McKee, 

who had worked out the geology of the Magruder 

Mountain area, Esmeralda County (fig. 126.1) prior to 

1960 and applied Nelson's terminology to the Precambrian ( ~) and Cambrian rocks ·exposed there. 

McKee kindly showed us this section in detail and 

also worked part time with us during 1961. 

Included in the section are 3 units, the Wyman, 

Reed, and Deep Spring Formations, that have yielded 

no fossils and are therefore regarded as probably of 

Precambrian age; 4 units, the Campito, Poleta, Harkless, and Mule Spring Formations, that contain abundant olenellid trilobites and other fossils of Early 

Cambrian age; and 1 unit, the Emigrant Formation, 

of Middle and Late Cambrian age. The total thickness of this section is at least 13,000 feet, of which 

about 3,600 feet is Precambrian ( ~) , 7,500 feet is 

Lower Cambrian, and 1,900 feet is Middle and Upper 

Cambrian (fig. 126.2). The Lower Cambrian rocks 

in the Silver Peak region were named the Silver Peak 

Formation by Turner (1902, p. 264-265). Later, the 

term Silver Peak was used by Walcott ( 1908-, p. 185) 

in a group sense for part of this series of rocks. Because of the vague original usage of th.e term Silver 

Peak, and also because it includes too many rock 

types to be usable as a modern map unit, Nelson 

( 1962, p. 144) has abandoned the term. Accordingly, 

10 20 

<)(!)~ 

0 30 MILES ----'"?:.__,.-lf---.:....1---~ 

CONTOUR INTERVAL 1000 FEET 

EXPLANATION 

E 

Emigrant Formation 

M 

Mule Spring Limestone 

H 

Harkless Formation 

p 

Poleta Formation 

c 

Montenegro Member of 

Campito Formation 

D 

Deep Spring Formation 

R 

Reed Dolomite 

w 

Wyman Formation 

1-l 

Location of measured section. 

X 

Type locality of Emigrant 

Formation 

FIGURE 126.1.-Index map of Esmeralda County, showing location of measured sections of Precambrian ( ?) and Cambrian rocks. Letters show formations measured at each section. Shaded areas are basins. 
10,000'-

9000'-

8000'-

7000'-

6000'-

5000'-

4000'-

3000'-

c 

.~ 

.Q 

E 

113 

(.) 

t 

J: 

0 

...J 

Mule Spring 

Limestone 

c 

2 

113 

E 

0 

..... 

.B 

·c. 

E 

c 

0 

:0: 

113 

E 

0 

..... 

Cll 

Cll 

Q) 

~ 113 

:I: 

c 113 

Q) 2 

113 

0 E Q.. 0 

..... 

t-- ~ 

:_::·.;.:-,..::..:..:-::·.:....:..::-:7' 

:..:..7.:.:.:.--:-: ·.:.:...--:· 

""~:::·~· ... ·-·~·::..c.. 

~::7:::-::~;j ......... 

IIIII 

I I I I I 

vI I I J 

> 

ARTICLE 126 

Platy to flaky gray and olive-gray claystone 

Interbedded limestone and chert 

Olive-gray claystone and siltstone containing abundant trilobites 

Mostly well bedded somewhat mottled limestone containing abundant concretionary algal structures 

(Girvanella) 

Siltstone with limestone interbeds; west and south of Goldfield vitreous pinkish-gray quartzite containing 

Scolithus is prominent 

Greenish-gray and light-olive-gray p·laty siltstone containing abundant olenellid trilobites and other fossils 

in some layers 

Mainly greenish-gray slabby .to blocky quartzitic siltstone containing sparse to abundant reef like bodies of 

archeocyathid-bearing limestone from 1 to 50 feet thick. In most places lowest beds are platy greenish 

siltstone with thin carbonate layers containing purple pisolites 

Gray limestone 50 to 100 feet thick 

} Platy greenish siltstone containing beds of blocky quartzite and mottled blue-gray limestone from 2 to 6 

feet thick 

} 

} 

} 

} 

} 

Mainly thick- to thin-bedded limestone locally containing abundant archeocyathids 

Greenish-gray slabby to platy siltstone; locally contains olenellid trilobites 

Mainly very thick bedded blocky dark-gray to black quartzite; locally cross-stratified; section incomplete 

Interbedded thick units of carbonate-rock, quartzite, and siltstone 

Gray and pale-orange limestone and dolomite, mostly well bedded in '12 -foot to 6-foot beds; cross-stratification common; oolitic, pisolitic, and pelletal structures in some beds. Subordinate quartzite and 

siltstone 

light-gray and pale-orange massive to very thick bedded fine to coarsely crystalline dolomite; some oolitic 

and pisolitic structures 

} 

Chiefly gray platy siltstone with laminated sandy limestone interbeds 1 to 6 inches thick; a few lenticular 

to continuous beds of light-gray limestone and dolomite as much as a few tens of feet thick 

Granite, intrusive into Wyman Formation 

FIGURE 126.2.-Generalized composite section of Precambrian(?) and Cam brian rocks, Esmeralda County. 

D25 
D26 GEOLOGICAL· SURVEY RESEARCH 19 6 2 

Nelson's terminology, slightly amended, is applied to 

the rocks in Esmeralda County, which includes the 

type area of the Silver Peak of former usage. 

The Wyman Formation, consisting chiefly of platy 

siltstone, interlayered thin sandy limestone beds, and 

local fairly thick lenses of gray limestone and dolomite, 

is the oldest map unit in the county and, as shown 

diagrammatically on figure 126.2, its lower boundary 

is an intrusive contact, where observed in the area 

mapped. The maximum exposed· thickness of the 

Wyman is not much more than 1,000 feet, but the 

amount of section cut out is not known. In most 

places the Wyman is metamorphosed to spotted hornfels or schist, but on the west flank of Mount Dunfee 

(fig. 126.1) it is only slightly metamorphosed and 

clearly lies conformably beneath the Reed Dolomite, 

which consists mainly of massive very thick bedded 

light-gray commonly coarsely crystalline dolomite. 

Similar conformable relations between the Wyman 

and the Reed were seen east of Lone Mountain. Elsewhere in the county the Reed rests in some places 

in thrust relation on the Wyman, and in other places 

the structural relation of the two units is obscure. 

Accordingly, Nelson's (1962, p. 140-141) observation 

that an unconformity separates the Wyman and Reed 

Formations is not supported by our findings in Esmeralda County. The wide lithologic variation in 

the vVyman at its contact with the Reed may be due 

to a combination of original lenticularity of beds 

within the Wyman and a thrust relation in some places 

between the Wyman and Reed, rather than to an unconformity. 

The name Reed Dolomite is herein retained, in 

preference to Nelson's (1962, p. 141) Reed·Formation, 

because the unit is composed almost entirely of thickbedded very-light-gray to yellowish-gray dolomite. It 

is a distinctive unit that forms prominent outcrops. 

The Deep Spring Formation, which overlies the 

Reed, is composed mainly of distinctly bedded limestone and dolomite, much of which shows crossstratification, and subordinate quartzite and siltstone. 

Biscuit-shaped algal growths, pisolites, and pelletal 

structures are common. The contact between the Reed 

and the Deep Spring is well exposed in the section on 

Mount Dunfee and is clearly conformable. 

The uppermost part of the Deep Spring Formation 

and the lower part of the overlying Campito Formation are not exposed on Mount Dunfee where the contact between these two units is a fault. However, 

E. H. McKee 1 has found these two formations to be 

1 McKee, E. H., 1962, The stratigraphy and structure of a portion 

of the Magruder Mountain-Soldier Pass quadrangles, CaliforniaNevada: California Univ. Ph.D. thesis, 108 p. 

conformable in the east end of Magruder Mountain 

a few miles to the west (fig. 126.1). The· Andrews 

Mountain and Montenegro Members of the Campito 

Formation, as subdivided by Nelson (1962, p. 141), 

are distinctive lithologic units in Esmeralda County 

and are highly useful in working out the complex 

structural pattern. The Andrews Mountain Member 

is mainly dark-gray blocky quartzite, and the Montenegro Member is largely greenish-gray siltstone. The 

Montenegro ~iember contains abundant olenellid trilobites; we have not found any fossils lower in the 

section. Thus the boundary between the Cambrian 

and Precambrian is not certainly fixed. Nelson ( 1962, 

p. 140) indicates that olenellid trilobites occur in the 

upper part of the Andrews ~fountain Member. It 

therefore seems likely that at least the upper part of 

this member in Esmeralda County is Lower Cambrian. 

The limestone that forms the lower part of the . 

Poleta Formation contains abundant archeocyathids 

and forms a very useful marker. This carbonate unit 

seems to differ greatly in thickness from place to 

place, but we have not been able to ascertain how much 

of the variation is due to original lenticularity and 

how much to structuraJ slicing. The rest of the Poleta 

Formation is a sequence of platy siltstones containing 

locally abundant trilobites interlayered with blocky 

quartzite beds and bluish-gray mottled li1nestone beds, 

and capped by a limestone unit 50 to 100 feet thick 

that contains sparse archeocyathids. The upper part 

of the Poleta is also a highly distinctive map unit. 

The blocky quartzitic siltstone that makes up the 

lower part of the Harkless Formation (fig. 126.2) is 

recognized mainly by the small reeflike masses of 

archeocyathid limestone that it contains and by its 

greenish-gray color. The unit is absent in many parts 

of Esmeralda County, and we attribute this mainly 

to structural complications. The greenish-gray platy 

siltstone that forms the upper part of the Harkless is 

very difficult to distinguish from the Montenegro 

Member of the Campito Formation except by the fauna 

that it contains. 

The upper part of the Harkless Formation in the 

Montezuma Peak area west of Goldfield includes beds 

of limestone and sandy limestone interbedded with 

platy siltstone and quartzite that, according to Nelson 

(oral communication, 1960), resemble the younger 

Saline Valley Formation of the northern Inyo and 

vVhite 1\fountains (Nelson, 1962, p. 142). Sim~lar beds 

also have been recognized about a mile northeast of 

Mount Dunfee. This unit is not present everywhere, 

however, and where present it has been included in 

the Harkless Formation. In the hills northwest of 

the junction between U.S. 95 and State Highway 3 
ARTICLE 127 D27 

and in the hills 6 miles south of Goldfield and west 

of U.S. 95, the uppermost Harkless includes beds of 

coarse vitreous pinkish-gray quartzite, some of which 

contain Scolithlus. This quartzite was also recognized 

as a bed about 2 to 4 feet thick, west of Montezuma 

Peak where it seems to pinch out. It has not been 

found elsewhere. These quartzite beds lithologically 

resemble and may correlate with the unit named the 

Zabriskie Quartzite 1\t[ember of the \Vood Canyon 

Formation by IIazzard {1937, p. 309) in the Nopah 

Range, In yo County, Calif. 

The name J\1ule Spring Limestone is herein used in 

preference to the J\1nle Spring Formation of Nelson 

{1962, p. 142) because the unit consists everywhere 

of distinctly bedded commonly mottled limestone and 

is a conspicuous marker unit that crops out prominently. Except where it is extremely metamorphosed, 

the J\1ule Spring is readily identified by the abundant 

concretionary algal structures ( Gi1·vanella) that it 

contains. 

In several ]ocnJities a few miles southwest of Goldfield the Mule Sprin;g Limestone of Early Cambrian 

age is overlain conformably by siltstones containing 

trilobites identified by A. R. Palmer (written communication, 19()0) as of ]\fiddle Cambrian age. These 

siltstones in turn are overlain by a sequence of limestone with interlayered chert, by claystone, and finally 

by thin-bedded limestone with cherty interbeds. This 

last unit has yielded fossils of Late Cambrian age. 

The entire sequence above the Mule Spring Formation is considered to be the Emigrant Formation and 

its age is revised to include J\1iddle as well as Late 

Cambrian rocks. However, details of the stratigraphy 

of the Emigrant, particularly the uppermost part, 

have not yet been satisfactorily worked out. 

From the relations seen, it is our interpretation that 

the entire sequence of Precambrian ( n, Lower Cambrian, and ]\fiddle and Upper Cambrian rocks in 

Esmeralda County is conformable. 

REFERENCES 

Hazzard, J. C., 1937, Paleozoic section in the Nopah and Resting §'prings Mountains, Inyo County, California: California Div. Mines Rept. 33, p. 289-339. 

Nelson, C. A., 1962, Lower Cambrian-Precambrian succession, 

White-Inyo Mountains, California: Geol. Soc. America 

Bull., v. 73,· p. 139-144. 

•rmner, H. W., 1902, A sketch of the historical geolog.v of 

Esmeralda County, Nevada: Am. Geologist, v. 29, p. 261-

272. 

Walcott, C. D., 1908, Cambrian sections of the Cordilleran 

area: Smithsonian Misc. Colln., v. 53, no. 5, p. 167-230. 

127. CAMBRIAN CARRARA FORMATION, BONANZA KING FORMATION, AND DUNDERBERG SHALE EAST OF 

YUCCA FLAT, NYE COUNTY, NEVADA 

By flARLEY BARNES, RoBERT L. CnmsTIANSEN, and F. J\1. BYERS, Jn., Denver, Colo. 

lVo1·T.; flone in ooopera.tion with U.S. A.toJu:ia .Bnergy Commission 

The Cambrian rocks underlying the Upper Cambrian 

Windfall Formation (Barnes and Byers, 1961) in the 

northeast corner of the Nevada Test Site (fig. 127.1) 

are described in this article. The section includes the 

Lower and J\1iddle Cambrian Carrara Formation, the 

Middle and Upper Cambrian Bonanza King Formation, and the Upper Cambrian Dunderberg Shale. It 

now seems advisable to apply the name Carrara Formation (Cornwall and JCleinhampl, 1961), rather than 

the names Latham Shale, Chambless Limestone, and, 

Cadiz Formation (Barnes and Palmer, 1961), to the 

entire transitional sequence between the quartzites of 

the Lower Cambrian \V'ood Canyon Formation and 

654085 0-62-3 

the carbonates of the Bonanza King Formation (fig. 

127.2). This change in usage 'yas suggested by A. R. 

Palmer (written and oral communications, October 

and November, 1961) following field examination of 

many sections below the Bonanza King Formation in 

southern Nevada and adjacent parts of California, 

bec.ause the Chambless Limestone cannot be correlated 

a~:oss the region with certainty. Palmer has also 

provided all fossil identifications used in this article. 

CARRARA FORMATION 

The Carrara Formation east of Yucca Flat is about 

1,960 feet thick and is divided into 7 subunits. Suh-
D28 GEOLOGICAL SURVEY RE.SEARJCH 19 6 2 

116"00' 

0 3 MILES 

~C~O~~~TO~U~R~I-NT-E-RV_A_LL2-00--FE-ET~ 

2 

FIGURE 127.1.-Map of part of Nevada Test Site east of Yucca 

Flat, Nye County, Nev., showing location of measured sections. A, subunits 1-5 of Carrara Formation; B, Jangle 

Limestone Member and subunit 7 of Carrara Formation; 0 

and D, Papoose Lake Member of Bonanza King Formation; 

E and F, Banded Mountain .1\:[ember of Bonanza King Formation.; F, Dunderberg Shale. 

units 1, 2, and 3 were correlated by Johnson and 

Hibbard (1957, p. 338) with the Pioche Shale of the 

G;oom district, subunit 4 (p. 338) with the Lyndon 

Limestone of the Groom district, and subunit 5 (p. 

339) with the Chisholm Shale of the Groom district. 

The J a~gle Limestone of Johnson and Hibbard ( 1957, 

p. 339) IS here recognized as a member of the Carrar·a 

Formation. Subunit 7, the highest of the subunits is 

equivalent to the lower paFt of Johnson and Hibba;d's 

Yucca Flat Formation ( 1957, p. 340). 

The lower half of the Carrara Formation consists 

of interbedded shale, siltstone, and limestone and is 

divided into three subunits. The lowest subunit is 

85 feet thick and consists of dark-yellowish-orange to 

pale-olive fissile clay shale and siltstone, grayish-red 

to. yellowish-brown thin-bedded very fine grained 

~ncaceous sandstone and quartzite, a~d a little yellowIsh-brown to grayish-red thin-bedded sandy limestone. 

The subunit is gradational with the underlying 

Zabriskie Quartzite Member of the Wood Canyon 

Formation of Hazzard ( 1937, p. 309) , and the basal 

contact is placed at the lowest occurrence of fissile 

shale. ·The second subunit of the Carrara is about 

285 feet thick and consists of laminated to thin-bedded 

medium-dark-gray to grayish-red limestone and silty 

limestone with interbedded fissile clay shale. The 

limestone and silty limestone have fairly regular to 

pl~ty ?edding and split into plates and shaly chips. 

Trilobite fragments are common. This subunit forms 

two low ridges underlain by limestone, with an intervening saddle eroded in shale. The third subunit is 

about 540 feet thick and consists of pale-brown to 

grayish-red fissile clay shale and laminated to thinbedded micaceous siltstone and sandstone with ·minor 

amounts of interbedded limestone and silty limestone. 

It forms a conspicuous brownish outcrop band. 

Subunits 4 and 5 and the Jangle Limestone Member 

of the Carrara Formation form two persistent zones 

of ridge-forming limestone with a less resistant shale 

between. Subunit 4 contains about 310 feet of lightto medium-dark-gray limestone with interbedded paler~d to dark-yellowish-orange shale, siltstone, and silty 

limestone. The rocks are thin bedded to laminated, 

with some discontinuous cuspate laminae. Locally the 

limestone is conspicuously oolitic and contains abundant Girvanella and trilobite fragments. Subunit 5 

contains about 170 feet of pale-reddish-brown to darkyellowish-orange fissile clay shale with interbedded 

laminated to thin-bedded silty limestone. About 100 

feet above the base of the subunit is a persistent ledgeforming 3-foot bed of medium-dark-gray limestone 

mottled with discontinuous cuspate laminae of palered siltstone, similar to the Jangle Limestone Member. 

The Jangle Limestone Member of the Carrara Formation is about 280 feet thick and consists of thin-bedded 

to laminated medium-gray limestone and silty limestone, much of which is mottled. The characteristic 

mottling results from the interlayering of dark-yellowish-orange to pale-reddish-brown discontinuous cuspate 

laminae with medium-gray laminae. The lower and 

upper parts of the member form ledges, and about 

135 feet in the middle forms slopes and contains 

abundant irregular laminae of silty limestone. Girvanella is locally abundant. 

The uppermost subunit of the Carrara Formation is 

about 290 feet thick and comprises rocks transitional 

between the underlying .shales and silty limestones and 

the overlying limestones and dolomites of the Bonanza 

King Formation. All but the lower 50 feet of this 

transitional unit "·as included by Barnes and Palmer 

( 1961, p. C102) in the Bonanza King Formation, but 

recent detailed work has shown that the lithology of 

subunit 7 is more like t.he Carrara Formation with its 

shales and silty limestone than the Bonanza King 
.UJ 

(!) 

<( 

!::: 

z 

:::> 

!::: 

z 

:::> 

CD 

:::> 

en 

~z C!Jo 0- ...JIou 

UJU.I 

(!)en 

UJ 

(!) 

<( 

Top of section: Catlri1 Member 

of Windfall Formation 

Dunderberg Shale 

z 

<( 

0:: 

IXl 

~ 

<( 

(.) 

Q) 

-ro 

...J 

~?-

Q) 

'"0 

'"0 

c 

0 

-ro 

E 

0 

u.. 

.... 

Q) 

.D 

E 

Q) 

~ 

c 

tlD - c c 

ro 

N 

c 

ro 

c 

0 

c:o 

'"0 

'Q) 

'"0 

c 

ro 

c:o 

D . 

. 

. 

. 

.Sandstone 

6500' 

3 

'\ 

6000' ~ -

0:: '"0 

----- / / IXl '"0 

2 Q) 

// // / ~ ~ 

~~ 

5500'~ 

1 5000' 

4500' 

::::::: = 

c 

0 

-ro 

E 

0 

u.. 

tlD· 

c 

ro 

N 

c 

ro 

c 

.o 

c:o 

Shale Silty limestone 

or siltstone 

Planar thick 

bedding 

Planar thin to 

laminated bedding 

Discontinuous 

cuspate 

laminated bedding 

giving mottled 

appearance 

!::: 

z 

:::> 

ARTICLE 127 

.... 

Q) 

.D 

E 

Q) 

~ 

Q) 

.:s:. 

ro 

....J 

Q) 

(/) 

0 

0 

a. 

ro 

a. 

3 

!::: 

z 

:::> 

CD 

:::> 

en 

4000' 

J J 

I J 

./ ./ 

/ / 

/ / / / 

UJ 

(!) 

<( 

Q) 

3500' ~ LL L '"0 

'"0 

11/11/~ i 

3000'1 ·1~1./1;~ '-' 

J I 

L 1 

I I t-?-

' ' ' I 

2 2500' 

1 

c 

0 

·-ro 

E 

0 

u.. 

ro 

.... 

.... 

ro 

{) 

!::: 

z 

::::> 

Jangle 

Limestone 

Member 

7 

6 

.5 

!::: 

z 

::::> 

CD 

::::> 

en 

1500' 

f----

4 

~z 

C!JQ 

oou -'"""" 

UJUJ 

C!Jen 

D29 

.. . . ..-..:. 

-:::=::~ 

I I T ~-- .. ·· 

c::;::r~ 

~-: ... ·.-.~ 

G 

lOOO'·e~-- ...::=; 

3 

----= 2 

2000' 

Base of section: Zabriskie Quartzite 

Member of Wood Canyon Formation 

. of Hazard (1937, p. 309) 

Limestone 

Limestone 

nodules and 

concretions 

Dolomite 

Chert nodules 

and lenses 

Fossil collection 

Letter symbol shows stratigraphic location of 

fossil collection. USGS fossil-collection number 

and stratigraphic horizon, in feet above bas 

of measured section, shown below: 

Colin. No. 

Q 3536-CO 

p {3535-CO 

3534-CO 

0 3533-CO 

N {3532-CO 

3531-CO 

M 3530-CO 

L 3545-CO 

K 3484-CO 

J 3483-CO 

I 3547-CO 

H 3766-CO 

G 3695-CO 

F 3546-CO 

E 3790-CO 

0 3789-CO 

C 3788-CO 

B 3787-CO 

A { 3786-CO 

3646-CO 

Feet 

6698 

6591 

6585 

6550 

6523 

6520 

6260 

1670 

1390 

1345 

1325 

1220 

925 

693 

440 

220 

129 

85-105 

FIGURE 127.2.-Section of Carrara Formation, Bonanza King Formation, and Dunderberg Shale measured east of Yucca Flat, 

Nevada Test Site (fig. 127.1). 
D30 GEOLOGICAL SURVEY RESEARCH 1 9 6 2 

Formation with its carbonate rocks relatively free of 

detrital materials. The characteristic lithology of the 

subunit is medium- to dark-gray thin-bedded limestone with irregularly distributed brownish- to reddish-weathering laminae of siltstone and dolomite. All 

gradations occur from well-bedded interlaminated 

limestone and siltstone to rocks with the mottled 

appearance of the underlying Jangle Member. In 

addition to these silty limestones, subunit 7 includes 

abundant light-gray poorly bedded limestones that 

typically contain small white irregularly shaped blebs 

of coarsely crystalline calcite. Near the top of the 

subunit, zones a few feet thick of mottled gray limestone characteristic of the lower part of the Bonanza 

King Formation are rather common. The top of the 

subunit is placed at the top of the highest silty bed 

in the transitional sequence. The discontinuity of 

individual silty beds that define the top of the unit 

results in thickness variations of as much as several 

tens of feet. 

The age of the Carrara Formation is Early and 

Middle Cambrian. Early Cambrian fossils of the 

Olenellus zone occur in subunits 2 and 3, from 85 to 

440 feet stratigraphically above the base of the formation (fig. 127.2, A-D). A single small collection from 

near the middle of subunit 3 contains the earliest 

Middle Cambrian Wenohemrnia-Stephenaspis zone (fig. 

127.2, E). Fossils probably equivalent to the early 

Middle Cambrian Kochaspis-Plagiura zone are found 

near the base of subunit 4 (fig. 127.2, F). Middle 

Cambrian fossils from the Albertella zone occur in 

subunits 4, 5, and 6 (fig. 127.2, H-K) and from the 

Glossopleura zone near the base of subunit 7 (fig. 

127.2, L). 

BONANZA KING FORMATION 

The Bonanza King Formation on the east side of 

Yucca Flat is subdivided into two members: the 

Papoose Lake Member, about 2,160 feet thick, and the 

Banded Mountain Member, abmit 2,440 feet thick 

(Barnes and Palmer, 1961, p. C103). The formation 

is equivalent to the upper part of Johnson and Hibbard's Yucca Flat Formation (1957, p. 340). 

The Papoose Lake Member comprises three subunits. Approximately the lower fifth of the member 

is made up of a distinctive dark-gray limestone thinly 

interbedded and interlaminated with slightly coarser 

grained medium-gray limestone. The laminae have · 

somewhat irregular cuspate forms, giving the rock a 

mottled appearance in two shades of gray. The subunit weathers to dark massive subrounded exposures. 

The basal subunit is equivalent to unit A of the upJ?er 

part of Johnson and Hibbard's Yucca Flat Formation 

(1957, p. 341). The overlying subunit of the Papoose 

Lake Member is well-bedded laminated to thin-bedded 

light- to medium-gray limestone with minor dolomite 

and several thin zones containing brownish-weathering 

siltstone laminae. The subunit contains virtually the 

only clastic material in the member and is a good local 

stratigraphic marker. The upper two-thirds of the 

Papoose Lake Member is more heterogeneous than 

either of the other subunits. It consists of three 

lithologic types in varied order. lVIuch of it is wellbedded light- to medium-gray thick-bedded dolomite 

and limestone. Light- to medium-gray laminated dolomite and limestone are dominant near the top of the 

member. The third lithologic type in this subunit is 

dark-gray dolomite with very irregular and cuspate 

thin beds and massive-weathering forms. vVithin these 

dark beds are abundant small white arcuate calcite 

stringers suggestive of shell profiles. This third type 

generally occurs in lenticular bodies a few feet thick, 

but the lowest of these is about 170 feet thick and 

persists throughout the area. 

The Papoose Lake Member in many places has been 

altered to a rather coarsely· crystalline light-gray· to 

faintly yellowish-gray dolomite with wispy remnants 

of the original rock types. Locally this dolomitization is stratigraphically controlled, but in different 

places it has affected virtually every part of the member. In the northwestern corner of the Jangle Ridge 

quadrangle it has obliterated the original lithologic 

character of almost the entire unit. The member has a 

measured thickness of 2,160 feet, but the measured section had to be offset in an altered zone and was correlated on some of the wispy remnants within it. The 

resulting measurement may be slightly in error. 

The overlying Banded Mountain Member of the 

Bonanza King Formation has three local subunits. 

The lowest of these is about 1,765 feet thick and is a 

strikingly banded sequence of laminated to thin tabular beds of light-gray dolomite and dark-gray limestone. The conspicuous color bands range in width 

from several inches to 15 feet. Dolomite. predominates 

over 1 imestone except for the basal 230 feet and a 

sequence extending from 600 to 735 feet above the 

base. Scattered nodules and lenticular beds of darkbrown-weathering chert and silty limestone are found 

at intervals throughout the subunit. The basal 230 

feet is a good stratigraphic marker. It is largely 

thin-bedded but massive-weathering resistant darkgray limestone mottled in various shades of gray, yellowish brown, and grayish orange; it also contains 

less resistant laminated to thin-bedded yellowish-brown 
ARTICLE 128 D31 

to very-pale-orange silty limestone. The mottling of 

the dark-gray limestone comes largely from the irregular cuspate form of the thin beds and in appearance is reminiscent of mottled beds near the base of 

the Bonanza IGng Formation. The lo:west 40 ·feet of 

the 230-foot sequence is yellowish-brown silty limestone, the "brown-weathering siliceous carbonate" referred to by Barnes and Palmer ( 1961, p. C102-C103). 

The middle and upper subunits of the Banded 

:!\fountain l\fember form two broadly contrasting light 

and dark outcrop bands. The contrast is increased by 

the deeply pitted weathering of the darker rocks in 

the upper subunit as opposed to the smoothly rounded 

weathering of the lighter rocks in the middle subunit. 

The light-colored middle subunit contains about 375 

feet of thick to very thin tabular beds of light- to yellowish-gray limestone, and has probably formed by 

alteration of darker beds. Its upper contact is conformable but sharp, its lower contact gradational. The 

upper subunit contains 300 feet of dark- to light-gray 

limestone in tabular to somewhat irregular thin beds. 

The upper, 10 feet of the subunit is composed of darkyellowish-brown and medium-gray thin to laminated 

irreO'ular beds of limestone that contain much bitu- o 

minous material and weather brownish gray. The 

middle and upper subunits of the Banded :!\fountain 

l\fember are equivalent to units C and D of the upper 

part of Johnson and Hibbard's Yucca, Flat Formation 

(1957, p. 341). 

The age of the Bonanza ICing Formation is Middle 

and Late Cambrian. Late Ca.mbrian fossils of the 

01•e7Jicephali8 zone are found at the base of subunit 3 

of the Banded ·:!\fountain Member and 40 feet below 

the top of that subunit (fig. 127.2 M-N). Three feet 

higher (fig. 127.2 N) are fossils of the Aphelaspis 

zone. Other Late Cambrian fossils· representing an 

unnamed zone occur 10 feet below the top of the subunit (fig. 127.2, 0). 

DUNDERBERG SHALE 

The Dunderberg Shale, 225 feet thick, is composed 

of pale-reddish brown fissile chty shale with thin interbeds of limestone. The shale is easily eroded and 

poorly exposed, but the thin-bedded limestone forms 

ledges, closely spaced in the upper fourth of the formation. Thin platy to wavy medium-gray beds of 

limestone in the lower part of the Dunderberg weather 

brownish gray and are similar to the limestone in the 

top 10 feet of the Bonanza IGng Formation. Limestone in the upper part of the Dunderberg Shale is 

li rrht olive rrray and occurs in flattened concretions b b 

and thin nodular and wavy beds; it is similar to the 

ledge-forming nodular limestone at the };lase of the 

overlying Catlin l\fember of the Windfall Format~on. 

The arre of the Dunderberg Shale is Late. Cambrian. 

Dunde1·bergia-zone fossils of early Late Cambrian 

Dresbach age are found at several levels (fig. 127.2, 

P-Q) in the formation. The basal beds of the overlying 'Vindfall Formation contain trilobites ?f the 

Elvinia zone of middle Late Cambrian Franconia age. 

REFER.ENCES 

Barnes, Harley, and Byers, F. M., Jr., 1961, Windfall Formation (Upper Cambrian) of Nevada Test Site and vicinity, Nevada: Art. 188 in U.S. Geol. Survey Prof. Paper 

424-C, p. C103-C106. 

Barnes, Harley, and Palmer, A. R., 1961, Revision of stratigraphic nomenclature of Cambrian rocks, Nevada Test 

Site and vicinity, Nevada: Art. 187 in U.S. Geol. Survey 

Prof. Paper 424-C, p. C100-C103. 

Cornwall, H. R., and Kleinhampl, F. J., 1961, Geological map 

of Bare Mountain quadrangle, Nye County, Nevada: U.S. 

Geol. Survey Geol. Quadrangle Map GQ-157. 

Hazzard, J. C., 1937, Paleozoic section in the Nopah and Resting Springs Mountains, Inyo County, California: California Jour. Mines and Geology Rept. 33, State Mineralogist, 

p. 273-339. 

.Johnson, 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. 
D32 GEOLOGICAL SURVEY RESEARCH 19 6 2 

128. AGE AND SEQUENCE OF METASEDIMENTARY AND METAVOLCANIC FORMATIONS, NORTHWEST OF NEW 

HAVEN, CONNECTICUT 

By CRAWFORD E. FRITTS, Denver, Colo. 

WMk done in cooperation with the Oonnecticnt State Geological and Natural History S1trvey 

Metasedimentary and metavolcanic formations 

northwest of New ~aven, Conn. (fig. 128.1), are near 

the eastern edge of a broad belt of rocks of Precambrian to Paleozoic age that extends from Long Island 

Sound through western New England to Canada. 

These rock;s underwent the progressive regional metamorphism described, in part, by Barth (1936). Age 

determinations on micas from southeastern New York 

and southwestern Connecticut suggest that the metamorphism occurred about 365 million years ago (Long 

and Kulp, 1958, p. 604). According to a recent revision of the geologic time scale (l{ulp, 1961, p. 1111) 

the metamorphism occurred in Middle to Late Devonian time. The age of the metamorphosed rocks, 

therefore, must be Devonian or older. 

Geologic ages ranging from Precambrian to Silurian 

and Devonian are assigned here to the Connecticut 

rocks on the basis of correlation with an established 

stratigraphic succession in southeastern Vermont. Direct correlation is impossible now, because mapping in 

the intervening area is incomplete, no fossils have been 

found in the Connecticut rocks, and some formations 

are covered by strata of Late Triassic age in central 

Connecticut and Massachusetts. The rocks in Vermont 

and Connecticut, however, are similar and occupy comparable structural and stratigraphic positions in and 

near a series of partly preserved domes east of the 

Green Mountain anticlinorium (Thompson, 1952, p. 20, 

pl. 4; Emerson, 1917, pl. 10; Rodgers and others, 1959, 

fig. 2). Possible equivalence of formations was postulated on the basis of reconnaissance rna pping by 

Rodgers (Rodgers and others, 195~, p. 6, 14, 15), and 

the stratigraphic section was modified in the course of 

recent detailed mapping by the author in the Ansonia, 

Mount Carmel, and Southington quadrangles. The 

sequence from Waterbury· Gneiss to W epa waug Schist 

in Connecticut appears to be approximately equivalent 

to the sequence from Mount Holly Complex to 'Vaits 

River Formation in Vermont, as shown in the table 

below. 

The metasedimentary and metavolcanic formations 

in Connecticut discussed in this article are cut by 

several intn1sives mentioned here for convenience, although some of them are not directly related to the 

subject under consideration. The W oodtick Gneiss, 

named here for W oodtick, Conn., in the Southington 

quadrangle, intruded the Waterbury Gneiss but is not 

known to have intn1ded rocks stratigraphically above 

this formation. The Prospect Gneiss (formerly part 

of the Prospect Porphyritic Gneiss) and the Ansonia 

Gneiss (formerly the Ansonia Granite of Carr, 1960) 

intruded the Straits Schist and the Southington MounApproximate equivalence of metasedimentary and metavolcanic formations in south-central Connecticut and southeastern Vermont 

Connecticut Vermont 

Geologic age 

Interpretation of nomenclature of Rodgers and others (1959, p. 14, 15) Nomenclature of Fritts Nomenclature of Doll and others (1961) 

"Main body" of Orange Phyllite Wepawaug Schist Waits River Formation Devonian 

Northfield Formation ·and 

Silurian 

Milford Chlorite Schist Metavolcanic and metasedi- ·s ~ Barnard Volcanic 

mentary rocks, undivided ::l 0 Member - 0"·""' 

00~ Ordovician 

West-central part of Orange Phyllite Derby Hill Schist 00 cs:s 

"fil s Moretown Member rn '-" 

:@~ 

West edge of Orange Phyllite and upper part of The Southington Mountain Schist Stowe Formation Ordovician 

Straits Schist Member of the Hartland Formation Ottauquechee Formation and 

Pinney Hollow Formation Cambrian 

Lower part of The Straits Schist Member of the Straits Schist Hoosac Formation Cambrian 

Hartland Formation 

Waterbury Gneiss Waterbury Gneiss Mount Holly Complex Pre cam brian 
73°7'30" 

41° . 

37' 

30" 

22' 

30" 

WATERBURY 

DOME 

73.00' 

ARTICLE 128 

LONG ISLAND SOUND, 

EXPLANATION 

I *H+++t I 

Buttress Diabase 

§' West Rock 

-

Diabase 0 

0 '"' B 

B 

Southington ~ 

Mountain Schist 

m 

Straits Schist 

UNCONFORMITY 

New Haven Arkose g~{~H 

"Rnu, upper member 

"Rnl, lower member 

W oodtick Gneiss 

UNCONFORMITY 

Woodbridge ~ Granite }~ ~ 

Oligoclase gran~te . or sodic quartz ~ 

dwnte 

1: ~:\Ya ~I 

Waterbury Gneiss 

KYANITE 

~~~~d··· 

~~ci---

Lpoa I Dashed where 

approximately located 

Ansonia Gneiss ..,..%-- .... , Quartz monzonitic to graniticgneiss; Fault 

possibly metamorphosed Woodbridge Granite 

Dashed where inferred 

BR9,PJ·o·a~~·l 

Prospect Gneiss 

DOp, granodioritic, quartz monzonitic, and minor granitic gneiss. 

OOps, granodioritic to granitic 

gneiss and metasedimentary 

schists, undifferentiated 

~ ~ U, upthrown side; - z D, downthrown side ;~ ow 

oo 

"'"' Oo 

§oswj 

Wepawaug Schist 

~0 "'z ::< 

(/) 

UNCONFORMITY 

m 

Metavolcanic and metasedimen· 

tary rocks, undivided 

Metadiabase and metabasalt intrusives and extrusives, chlorite 

schist, amphibolite, meta- agglomerate, minor serpentinized 

limestone, and phyllite 

[~~~11 Derby Hill Schist 

Od, fine-grained thinly laminated 

muscovite-albite-chlorite-quartz 

schist. 

Odq, impure quartzi~. with thin 

micaceous and chloritic layers 

z 

<( 

~ 

> 

0 

~ 0 

0 2 MILES 

I I 

WATERBURY SOUTHINGTON 

NAUGATUCK 

ANSONIA 

MOUNT 

CARMEL 

NEW 

HAVEN 

f----+--t WOOD -

MILFORD MONT 

INDEX TO 7'30" 

QUADRANGLES 

[--------~ 

! \ 

I 

- INDEX MAP 

OF CONNECTICUT 

D33 

li 

FIGURE 128.1.-Map showing generalized bedrock geology in part of south-central Connecticut. Geology in Naugatuck quadrangle modified from Carr (1960); in Ansonia, Mount Carmel, and Southington quadrangles based on detailed mapping by 

C. E. Fritts in progress since 1957; in Waterbury, Milford, and New Haven quadrangles based on reconnaissance by C. E. 

Fritts in 1959-61 and on Rodgers and others (1959) and Krynine (1950). 
D34 GEOLOGICAL SURVEY RESEARCH 19 6 2 

tain Schist but are not known to have intruded overlying formations. The Woodbridge Granite, named 

here for Woodbridge, Conn., in the Mount Carmel 

quadrangle, intruded the Wepawaug Schist before the 

climax of progressive regional metamorphism in Devonian time (Fritts, 1962). The ages of these four 

intrusives are discussed briefly below. Formations intruded by these rocks are overlain unconformably by 

the New Haven Arkose, which is part of the Newark 

Group of Late Triassic age. The West Rock Diabase, 

named here for West Rock in the New Haven quadrangle, intruded the New Haven Arkose at about the 

time that the Talcott Basalt of the Newark Group was 

extruded above· the arkose. The age of this diabase, 

therefore, is Late. Triassic. The Buttress Diabase, 

named here for a topographic feature known locally as 

The Buttress in the New Haven quadrangle, intruded 

West Rock Diabase at The Buttress, and is Triassic 

or. younger in age. 

The stratigraphic section recognized by Rodgers 

(Rodgers and others, 1959, p. 14) was deduced, in part, 

from the distribution of formations near the Waterbury dome (fig. 128.1). Formations were eroded from 

the western side of the dome after faulting and eastward tilting of the region during and (or) after 

Late Triassic time. East and south of the dome, 

however, the stratigraphic sequence is more complete, 

and most formations trend north-northeast. The easternmost formation (Milford Chlorite Schist of former 

usage) was assumed to be the youngest. 

The present interpretation of stratigraphy and structure in the map area differs from that of Rodgers in 

several ways: (1) The Prospect Gneiss, which was 

interpreted as a granitized metasediment (Rodge~s 

and others, 1959, p. 37), is believed to be a metamorphosed igneous rock, as suggested by Gregory 

(Rice and Gregory, 1906, p. 103). The Prospect forms 

stocks in the staurolite and kyanite zones, where the 

intensity of progressive regional metamorphism was 

too low to have formed the gneiss by granitization. 

(2) Metasedimentary rocks formerly included in the 

Prospect Gneiss, in the upper part of The Straits 

Schist Member of the Hartland Formation of Rodgers 

(Rodgers and other, 1959), and in the western part of 

the Orange Phyllite, were remapped and are here 

named the Southington Mountain Schist. ( 3) The 

names Orange Phyllite and Milford Chlorite Schist 

are here abandoned. ( 4) Rocks formerly assigned to 

the west-central part of the Orange Phyllite are here 

named the Derby Hill Schist, and rocks formerly assigned to the "main body" of the Orange Phyllite are 

here named the Wepawaug Schist. (5) Amphibolite 

west of the staurolite isograd in the Milford quadrangle, formerly mapped as a lens of hornblende gneiss 

in the Orange Phyllite, is physically continuous with 

lower grade metavolcanic rocks mapped as Milford 

Chlorite Schist by Rodgers and others ( 1959) farther 

east. ( 6) The rocks formerly mapped as Milford 

Chlorite Schist underlie rather than overlie the W epawang Schist (formerly the "main body" of Orange 

Phyllite). In the southeastern corner of the Ansonia 

quadrange, bedding in both formations strikes northeast and dips 30°-70° NW. Beds are right side up. 

Along the western side of the area of exposure of the 

'Vepawaug, however, beds are nearly vertical and 

tops face east. The Wepawaug overlies the Derby 

Hill Schist on the west, and meta volcanic and metasedimentary rocks, undivided, on the east. The map 

pattern (fig. 128.1) suggests an unconformity beneath 

the Wepawaug. The center of the Wepawaug is characterized by numerous small north-plunging folds, 

because the formation occupies the trough of a tight 

north-pl ungin·g syncline. 

The Waterbury Gneiss is part of a basement complex, which forms the core of the Waterbury dome 

(fig. 128.1). The name Waterbury Gneiss is restricted here to metasedimentary rocks that underlie 

Straits Schist. The predominant ·rock is a finegrained well-banded paragneiss composed of quartz, 

biotite, muscovite, oligoclase, kyanite, garnet, micro-

. cline, and magnetite. This rock contains more alumina 

and iron ~xide in the form of kyanite and magnetite, 

respectively, than other paragneisses in the map area. 

The 'Vaterbury also contains subordinate medium- to 

coarse-grained schists composed of quartz, muscovite, 

oligoclase, biotite, garnet, and ilmenite or magnetite. 

Waterbury Gneiss is highly contorted in many places 

and is characterized by more complex textures than 

overlying formations (Fritts, 1962) . The Waterbury 

is believed to have undergone progressive regional 

metamorphism more than once. The formation also 

contains numerous irregular bodies of felsic to intermediate meta-igneous rocks not known to have 

intruded overlying formations. There is no apparent 

relationship between emplacement of the meta-igneous 

rocks and formation of the Waterbury dome. For 

example, the largest body of W oodtick Gneiss, a quartz 

dioritic intrusive rock, is not in the center of the 

dome. Furthermore, the textures of these intrusives 

resemble the textures of Waterbury Gneiss rather 

than those of ·younger rocks. It is believed that emplacement of the meta-igneous rocks and a first metamorphism of Waterbury Gneiss occurred in preStraits time. The l\1ount Holly Complex of Precambrian age, which forms the cores of domes in 

southeastern Vermont, has a similar history (Doll and 
ARTICLE 128 D35 

others, 1961). A Precambrian ( ~) age, therefore, is 

assigned to the 'Vaterbury and Woodtick Gneisses. 

The Straits Schist is a relatively clean pelitic formation which overlies the Waterbury Gneiss unconformably, underlies the Southington Mountain Schist, 

and wraps around the core of the Waterbury dome. 

Straits Schist is the lower part of a unit named The 

Straits Schist Member of the Hartland Formation by 

Rodgers (Rodgers and others, 1959, p. 40). The predominant rock is a medium- to coarse-grained unhanded schist composed of quartz, muscovite, biotite, 

oligoclase, staurolite, kyanite (in the kyanite zone 

only) , and ilmenite. In the Southington quadrangle, 

the formation also contains subordinate amphibolite 

and minor plagioclase-rich paragneiss, which are believed to repres~nt metamorphosed graywacke or tuff. 

Straits Schist commonly is uncontorted, although it 

is crenulated in some places along the southern side 

of the Waterbury dome. In contrast to Waterbury 

Gneiss, Straits Schist is characterized by simple textures and uniform grain size. The schist probably 

underwent progressive regional metarnorphism only 

once. The Straits is similar to the Hoosac Schist of 

Early Cambrian age, which unconformably overlies 

rocks of Precambrian age in l\1assachusetts and Vermont (I:Ierz, 1961; Doll and others, i961). Thus, a 

Cambrian ( ~) age is assigned to the Straits Schist. 

The Southington Mountain Schist includes all metasedimentary and metavolcanic rocks above the Straits 

Schist and below the Derby Hill Schist. The type 

locality of the Southington l\1ountain Schist is near 

New Britain Reservoir on Southington Mountain in 

the Southington qtmdrangle. Interlayered mediumgrained paragneiss and fine- to medium-grained 

graphitic muscovite schist predominate. The formation is characterized by ribbon-like banding. The 

thickness of bands ranges from less than 1 inch to 

several tens of feet, but commonly is only a few inches. 

In the kyanite zone, schist bands contain quartz, 

muscovite, biotite, oligoclase, garnet, staurolite, kyanite, and chlorite; paragneiss contains quartz, sodi~ 

plagioclase, biotite, muscovite, garnet, staurolite, and 

minor kyanite (near the base of the formation). Amphibolite bands believed to represent metamorphosed 

graywacke or tuff are thinner but more numerous in 

this formation than in the Straits Schist. The formation also contains minor calc-silicate roeks and im'pure 

marble. The Southington Mountain Schist occupies 

a position comparable to that of rocks mapped above 

the Hoosac Schist as Pinney Hollow, Ottauquechee, 

and Stowe Formations, undifferentiated, near domes 

in southeastern Vermont (Doll and others, 1961). The 

age of the Pinney I:Iollow is Early Cambrian, the age 

of the Ottauquechee is Middle Cambrian, and the 

age of the Stowe is Late Cambrian and Early Ordovician (Cady, Albee, and Murphy, 1962). The age 

of the Southington l\1ountain Schist, therefore, is 

Cmnbrian ( ~) and Ordovician ( ? ) . 

The Derby Hill Schist, 'Yhich overlies the Southington Mountain Schist, contains fine-grained thinly 

laminated argillaceous metatuff and impure quartzite. 

The Derby Hill Sehist is named here for Derby Hill 

in the Ansonia quadrangle, Connecticut. The type 

locality is on the west side of the hill. The metatuff 

predominates and is characterized by layers a few 

millimeters thick composed almost entirely of muscovite, which are separated by layers of similar thickness composed of quartz and layers of intergrown 

albite and chlorite. Numerous veins and lenses of 

younger quartz have been injected between these layers.· 

In northern exposures the schist is characterized by 

conspicuous shear cleavage, but to the south the rock 

is crenulated rather than sheared. A quartzitic member west of the Housatonic River in the Ansonia 

quadrangle probably is continuous with impure quartzite exposed east of the river in the l\1ilford quadrangle. 

This member strongly resembles parts of the Savoy 

Schist (Ordovician) of l\1assachusetts and the Moretown Formation of Vermont. The age of the Moretown, w hieh over lies the Stowe, is believed to be 

Middle Ordovician (Cady, 1960, p. 554). Thus, an 

Ordovician· ( ~) age is assigned to Derby Hill Schist. 

The metavolcanic and metasedimentary rocks, undivided, south and east of the Wepawaug Schist include intrusive and extrusive metadiabase and metabasalt, chlorite schist, amphibolite, meta-agglomerate, 

minor serpentinized limestone, and phyllite. The intrusives and extrusives apparently represent the climax 

of local volcanic activity in Ordovician time. These 

rocks, which overlie Derby Hill Schist, occupy a position comparable to that of the Barnard Volcanic 

Member of the l\1issisquoi · Formation of Doll and 

others ( 1961). The Cram Hill Formation, which 

occupies a similar position in northern Vermont, is 

believed to be Middle Ordovician in age (Currier and 

Jahns, 1941, p. 1496) . 

The Wepawaug Schist is named for the Wepawaug 

River in the Ansonia quadrangle, Connecticut. The 

type locality is along this river south of Wepawaug 

Reservoir. 'Vepawaug Schist consists mainly of interlayered fine- to medium-grained argillaceous, siliceous, and minor caleareous rocks of chlorite to kyanite 

grade. In the chlorite zone (east of the garnet isograd) the predominant rock is carbonaceous phyllite 

composed mainly of quartz, muscovite, chlorite, and 

minor albite. Some layers a few inches thick are 
D36 GEOLOGICAL SURVEY RESEARCH 19 6 2 

quartz rich and others are muscovite rich. West of 

the garnet isograd, the rocks are fine to medium 

grained and consist of interbanded quartz-rich paragneiss and carbonaceous or graphitic muscovite schist. 

Garnet, biotite, staurolite, and kyanite are present in 

rocks of appropriate composition and metamorphic 

grade. Garnets are found on the low-grade side of 

the biotite isograd in this area, because the ratio 

MgO/FeO in vVepawaug Schist is low. In the staurolite and kyanite zones, the formation also contains 

subordinate thin bands of amphibolite. Bodies of 

subordinate impure crystalline limestone as much as 

75 feet thick and 450 feet long are widespread, but 

are more numerous in the upper part of the formation. 

The limestone, which is approximately 50 percent 

calcite, is medium dark gray to medium bluish gray 

where fresh, but weathered surfaces have brown rinds 

·as much as 1 inch thick, which are composed of quartz, 

muscovite, chlorite, and other silicate minerals. Similar limestones are characteristic of the Waits River 

Formation and a few are found in the underlying 

Northfield Slate of Vermont. The Northfield is 

Middle Silurian and the Waits River is Silurian and 

Devonian in age (Cady, 1960, p. 556). A Silurian 

and Devonian age, therefore, is assigned to the W epawaug Schist. 

The metasedimentary and metavolcanic formations 

in the map area were deposited during three main 

cycles of sedimentation. The predominant paragneiss 

of the Waterbury Gneiss, which contains moderate 

amounts of alumina and iron oxide, probably was derived from an area that underwent deep weathering 

and perhaps laterization. Deposition of the Waterbury was followed by progressive regional metamorphism and emplacement of the W oodtick Gneiss 

and other meta-igneous rocks in Precambrian time. 

The Straits, Southington Mountain, and Derby Hill 

Schists, and the overlying meta volcanic and metasedimentary rocks, undivided, reflect transition from 

relatively clean pelitic sediments to impure geosynclinal sediments in which volcanic debris was abundant. These rocks were deposited in Cambrian and 

Ordovician time before the Taconic orogeny. During 

a period of renewed subsidence after the Taconic 

orogeny, the Wepawaug Schist was deposited unconformably on older rocks. All of the metasedimentary 

and metavolcanic formations were folded or refolded 

and underwent progressive regional metamorphism 

in Middle to Late Devonian time during the Acadian 

orogeny. The Prospect and Ansonia Gneisses, which 

intruded rocks unconformably beneath the Wepawaug 

Schist, probably were emplaced during either the 

Taconic or the Acadian orogeny, and are Ordovician 

or Devonian in age. The Woodbridge Granite, which 

intruded the Wepawaug Schist, probably was emplaced during the Acadian orogeny, and is Devonian 

In age. 

REFERENCES 

Barth, T. F. W., 1936, Structural and petrologic studies in 

Dutchess County, New York, pt. 2, Petrology and metamorphism of the Paleozoic rocks : Geol. Soc. America 

Bull., v. 47, no. 6, p. 775-850. 

Cady, W. M., 1960, Stratigraphy and geotectonic relationships 

in northern Vermont and southern Quebec: Geol. Soc. 

America Bull., v. 71, no. 5, p. 531-576. 

Cady, W. M., Albee, A. L., and Murphy, J. F., 1962, Bedrock 

geology of the ·Lincoln Mountain quadrangle, Vermont: 

U.S. Geol. Survey Geol. Quad. Map GQ-164. (in press). 

Carr, M. H., 1960, The bedrock geology of the Naugatuck 

quadrangle: Connecticut Geol. and Nat. History Survey 

Quad. Rept. 9, 25 p. 

Currier, L. W., and Jahns, R. H., 1941, Ordovician stratigraphy of central Vermont: Geol. Soc. America Bull., v. 

52, no. 9, p. 1487-1512. 

Doll, C. G., and others, 1961, Centennial geologic map of Vermont: Vermont Geol. Survey. 

Emerson, B. K., 1917, Geology of Massachusetts and Rhode 

Island: U.S. Geol. Survey Bull. 597, 289 p. 

Fritts, C. E., 1962, Bedrock geology of the Mount Carmel and 

Southington quadrangles, Connecticut: U.S. Geol. Survey 

open-file rept. 

Herz, Norman, 1961, Bedrock geology of the North Adams 

quadrangle, Massachusetts-Vermont: U.S. Geol. Survey 

Geol. Quad. Map GQ-139. 

Krynine, P. D., 1950, Petrology, stratigraphy, and origin of the 

Triassic sedimentary rocks of Connecticut: Connecticut 

Geol. and Nat. History Survey Bull. 73, 247 p. 

Kulp, J. L., 1961, Geologic time scale: Science, v. 133, no. 

3459, p. 1105-1114. 

Lon~t L. E., and Kulp, J. L., 1958, A.ge of the metamorphism 

of the rocks of the Manhattan prong: Geol. Soc. America 

Bull., v. 69, no. 5, p. 603-606. 

Rice, W. N., and Gregory, H. E., 1906, Manual of the geology 

of Connecticut: Connecticut Geol. and Nat. History Survey Bull. 6, 273' p. 

Rodgers, John, Gates, R. M., and Rosenfeld, J. L., 1959, Explanatory text for preliminary geological map of Connecticut, 1956: Connecticut Geol. and Nat. History Survey 

Bull. 84, ?4 p. 

Thompson, J. B., Jr., 1952, Southern Vermont, in Guidebook 

for field trips in New England: Geol. Soc. America, 65th 

Ann. Mtg., Nov. 10-12, 1952. 
ARTICLE 129 D37 

129. AGE OF THE LEADVILLE LIMESTONE IN THE GLENWOOD CANYON, WESTERN COLORADO 

By ,¥. E. HALLGARTI-I and BETTY A. L. SKIPP, Denver, Colo. 

The Leadville Limestone in the Glenwood Canyon 

near G1enw·ood Springs in western Colorado contains 

endothyrid faunas which may be useful in determining 

the age of the formation. The Early Mississippian 

age currently recognized by the U.S. Geological Survey 

was determined from macrofossils studied by Girty 

( 1903) . Near the Colorado and Utah State line, 

however, rocks of Meramec (Late Mississippian) age 

have been recognized (Rothrock, 1960), and on the 

basis of n1ore recent work the Leadville in the White 

River Plateau area may range from Kinderhook to 

Meramec in age as inferred from the occurrence of 

Eumet1'ia verneuiliana (Hall) (N. W. Bass and S. A. 

Northrop, written communication, 1962). The endothyrid faunas likewise suggest that a part of the 

Leadville may be as young as Meramec. 

The Leadville Limestone is well exposed near the 

east end of the canyon at the Garfield and Eagle 

County line where it consists of two recognizable 

parts (fig. 129.1). The lower part, about 85 feet 

thick, is a sequence of interbedded sandy and cherty 

limestone and dolomite beds which includes the Gilman 

Sandstone as a basal member. The age of the lower 

FEET 

c 0 

Ill 

·a 

Q. 

·a u 'iii Ill Ill E 25 :i Ill 

o:; o:; 

,; t: Q. Ill n Q. :J o:; -?-t-?- Q. 

Q. 

:J 50 

75 

Gl 

110 c Ill 

Ill Ill 

.Q 0 

Q. , 'iii c: 100 Ill Ill 

'iii 

Ill 6 

:i 8 t: o:; -E Ill 

~ Gl Q. 

0 , .. ...I c Gl 125 i ~ 

0 

...I 

.. ;S~ 

:§i~ 150 

0~~ 

I I 0 I 0 

ol 0 I a 

0 I 0 

ol 0 I• 0 I 0 

ol 0 I• 0 I 0 

•I 0 I• 0 I 0 

o I 0 Jo 0 I 0 

ol 0 lo 0 I 0 

01 0 lo 0 I 0 

/ I 

l l 

I 

I L 

"" "" 

t::.f e:.Le:. 

I I 

"" "" 

I 

·I I· e:. I e:. t::. I 

I 

·l l· 

I e:. I e:. I 

} Endothyra aft. E. scitula 

Septaglomospiranella sp. 

} 

EXPLANATION 

Plectogyra 

tumula [TI 

limestone 

Dolomite 

Sandy limestone 

Sandy dolomite 

Oolitic limestone 

Chert nodules 

~ and lentils 

FIGURE 129.1 .-Section 0f Leadville Limestone· in Glenwood 

Canyon showing fossil zones. 

part is probably Kinderhook and Osage. The upper 

part, about 80 feet thick, is formed by massive oolitic 

cliff-fonning limestone which contains endothyrids 

only in the lower half. 

Three genera of Foraminifera were identified in the 

Leadville-Pleotogyra tumula Zeller, Endothyra a:ff. 

E. soitula Toomey (E. symmetrioa Zeller), and Septaglomospiranella sp. Lipina. 

In the Cordilleran trough area Pleotogyra tumula 

is in rocks no younger than Osage, and Endothyra 

soitula is restricted to Meramec (Zeller, 1957, p. 694; 

Skipp, 1961). In the Glenwood Canyon area Pleotogyra tumula and Endothyra a:fi. E. soitula occur in 

similar distinct zones. Pleotogyra tumula occurs most 

abundantly in a zone about· 20 feet thick in the lower 

part of the oolitic limestone and only sparingly in the 

overlying 15 feet of limestone. A few Endo,thyra 

aff. E. soitula and one Septaglomospiranella were 

found in a 10-foot zone about 40 feet above the base 

of the unit. None was found in the upper 35 fee't 

of the Leadville, and its age remains uncertain. However, because rocks of Chester age have not been 

found in western Colorado, the upper part may be of 

Meramec age also. Septaglomospiranella has been 

found only in the Tournaisian (Lower Mississippian 

equivalent) of the Soviet Union (Lipina, 1955), but 

in the Redwall Limestone Skipp has found it rarely in 

the lower Meramec. 

Zonation and correlation of the endothyrid faunas 

in the Cordilleran geosyncline area by Zeller (195'7), 

and more recently in the Idaho and northern Arizona 

areas by Skipp, suggest that the Leadville in the 

Glenwood Canyon area may be as young as Meramec. 

Therefore, the boundary between rocks of Osage and 

Meramec age, as inferred from the endothyrid faunas, 

seems to be in the massive oolitic cliff-forming limestone where stratigraphic breaks are not apparent and 

deposition may have been continuous. However, there 

appears to be a rather sharp faunal break at the base 

of the Endothyra aff. E. soitula zone which may be' 

the boundary between the Osage and Meramec . 

REFERENCES 

Girty, G. H., 1903, The Carboniferous formations and faunas 

of Colorado: U.S. Geol. Survey Prof. Paper 16, 546 p. 

Lipina, 0. A., 1955, Foraminifera of the Tournaisian Stage 

and upper part of Devonian of the Volga-Ural region and 
D38 GEOLOGICAL SURVEY RESEAR-CH 19 6 2 

western slopes of the Central Urals [Foraminifery turneiskogo iarusa i verkhnei chasti devona 'V olgo-Ural 'skoi 

oblasti i zapadnogo sklona Srednego Urala] : Trudy IGN, 

AN-SSSR, No. 163 (geol. seriia no. 70), p. 46. 

Rothrock, D. P., 1960, Devonian and Mississippian Systems in 

Colorado, in Guide to geology of Colorado: Geol. Soc. 

America, p. 17-23. 

Skipp, Betty A. L., 1961, Stratigraphic distribution of endothyroid Foraminifera in Carboniferous rocks of the 

Mackay quadrangle, Idaho: Art. 236 in U.S. Geol. Survey 

Prof. Paper 424-C, p. C239-C244. 

Toomey, D. F., 1961, Endothynt scituln, new name for E. syntmct-rica Zeller, preoccupied: Cushman Lab. Foram. Research Contr., v. 12, pt. 1, p. 26. 

Zeller, E. J., 1957, Mississippian endothyroitl Foraminifern 

from the Cordilleran geosyncline: Jour. Paleontology, v. 

31, p. 679-704. 

130. TYPE SECTIONS FOR THE MORROW SERIES OF PENNSYLVANIAN AGE, AND ADJACENT BEDS, 

WASHINGTON COUNTY, ARKANSAS 

By LLOYD G. HENBEST, "\Vashington, D.C. 

The Morrow Series in Washington County, Ark., 

is the standard of reference and the type section for 

the Lower Pennsylvanian rocks of the midcontinent 

region. The Washington County section cont~ins the 

most varied and comprehensive record of Early Pennsylvanian life so far reported in a single succession. 

This article designates a type section, lists characteristic exposures, and outlines the history of the name 

of each named unit of the Morrow and adjacent beds 

0 20 40 60 80 100 MILES 

FIGURE 130.1.-lndex map of northwestern Arkansas, showing 

area that contains type sections for Morrow Series in 

southern part of Washington County. 

in vVashington County (fig. 130.1), with the exception 

of the newly named Dye Shale and Trace Creek Shale 

Members of the Bloyd Formation, which are described 

in the accompanying Article 131. The stratigraphic 

units herein treated are described in figure 131.1 of 

that article. 

PITKIN LIMESTONE, MISSISSIPPIAN 

The Pitkin Limestone of ~fississippian (Chester) 

age was named by Ulrich (1904, p. 109), who substituted the name Pitkin Limestone for the term 

"Archimedes Limestone" of Owen (1858, p. 34, 115), 

Simonds (1891, p. 55), and other authors in northwest Arkansas. It was named from exposures in the 

vicinity of the Pitkin Post Office, Washington County. 

The nearest, the most extensively and conspicuously 

exposed, and the most informative section of the 

Pitkin Limestone in the vicinity of Pitkin is in the 

30- to 50-foot cliff along the West Fork of vVhite 

River at the west base of Bloyd Mountain. This cliff, 

half a mile long, near the center of the west side of 

sec. 4, T. 14 N., R. 30 W., is hereby designated as the 

type section. The Pitkin Limestone as represented 

in this cliff has generally been consistently identified, 

defined, and mapped by Simonds, Purdue, and later 

authors in northwest Arkansas and adjacent Oklahoma. Purdue (1907, map), however, misidentified 

a small area of Prairie Grove Limestone at the Pitkin 

Post Office as the Pitkin Limestone. This understandable error does not affect the designation of a type 

locality because Purdue was not the author of the 

term Pitkin and did not express an intent to revise 

the name, and the type section designated above repre-
ARTICLE 130 D39 

sents the Pitkin as identified and as mapped by everyone, including Purdue himself. 

MORROW SERIES, PENNSYLVANIAN 

The rock sequence in northwest Arkansas now 

known as the ~1orrow Series ''"as first recognized by 

the paleobotanist Lesquereux (1860). Lesquereux was• 

also the first to recognize that the rocks of the ~1orrow 

Series belong in the Pennsylva.nia.n ('Upper Carboniferous) nuther than in the ~1ississippian (Lower Carboniferous) System. Until 1895, however, other paleonj·ologists and geologists classed the ~1orrow as 

:Mississippian because it contains Pent'J•e1nites and certain other marine, metazoan fossils that characterize 

the ~1ississippian. 

The "Pentremital Limestone" and the "coal bearing 

shale"· of early authors were included in the "Boston 

Group" of the Branner Survey ('in Simonds, 1891, 

p. XIII), but the flora was restudied by 'Vhite (1895, 

p. 316-318; 1900, p. 817) and the fauna was reviewed 

by Ulrich (1904, p. 109-113) and Girty (1905, p. 8), 

all of whom confirmed the age determined by Lesquereux. The term Boston was both a homonym an<J 

a synonym of previous stratigraphic names. Ulrich 

( 1904, p. 109) substituted the term Morrow for Boston 

without designating a type area. A year later Adams 

:tnd Ulrich ( 1905, p. 4) stated that "The name is derived from the post office of l\1orrow, in 'Vashington 

County, Ark., just south of which a high hill affords 

a nearly complete section of the formation." This 

statement. constitutes a first revision. The "high hill" 

can be no other than Hale l\1ountain. 

HALE FORMATION 

The flale Formation was described and named by 

Simonds ( 1891, p. 75-82) a~ the "Washington Shale 

and Sandstone." Simonds' term proved to be a junior 

homonym. Taff (1905, p. 4) renamed the unit as the 

"I-InJe Sandstone Lentil" (now classed as a formation) 

from its chn,r:teteristic development in Hale Mountain. 

l-Ie presei1ted significant information on the character 

and distribution of the formation and included the. 

unit in his geologic map. In another publication the 

same year, Adams and Ulrich (1905, p. 4) briefly mentioned the name in the text, but did not include it 

elsewhere in the text or in the columnar section and 

geologic map, which indicates that recognition of the 

division was an afterthought following Taff's work. 

Other confirmation of Taff's authorship appears in 

reports by Purdue (1907, p. 3) and Purdue and .Miser 

(1916, p. 14), which deal with closely connected areas. 

Those authors were intimately associated with the 

geology, geologists, and surveys involved. It is not 

known whether the Adams and Ulrich or the Taft' 

folio was published the first in 1905, but it is now 

known that Taft' was the true author of the name. It 

therefore seems that Taff's priority should be accepted 

regardless of uncertainty on the exact date of publication, and it thus seems that vVilmarth ( 1938, p. 896) 

and Hen best ( 1953, p. 1936) were mistaken in crediting Adams and Ulrich as the authors. 

The most complete and informative exposure of the 

Hale Formation in Hale Mountain is in a very small 

area in and around a box canyon beginning at a high 

waterfall over the Prairie Grove l\1ember of the Hale. 

This locality is .near the center of the north side of 

Hale l\1ountain in a ravine that heads at the Hale 

l\1ountain School near the center of the west side, 

sec. 7, T. 13 N., R. 32 vV. (Henbest, 1953, p. 1948, 

no. 3). This section comprises a typical development 

of the unit and is hereby designated as the type locality of the Hale Formation. .The exposure described 

by Giles and Brewster ( 1930, p. 131) is not nearly so 

complete. 

The Cane Hill Member of the Hale Formation was 

first recognized as a stratigraphic entity by Simonds 

( 1891, p. 75), who described it as the lower division 

of his "vVashington Shale and Sandstone." Though 

the name vVashington was found by Taft' (1905, p. 4:) 

to be unavailable, a restudy (Henbest, 1953, p. 1938) 

confirmed Simonds' stratigraphic observations and determined that the 1 ower shale division of the Hale is 

a mappable unit. The name Cane Hill Member was 

applied because of typical development of the unit 

"* * * -in the southern part of Washington County, 

in the vicinity of Cane Hill * * *" (1953, p. 1938). 

The exposures in the hillside and cuts on the west side 

of State Highway 59 about 3 miles along the road east 

of south from Evansville in the SWl!t,SE%, sec. 35, 

T. 13 N., R. 33 vV., at the common boundary of Washington and Crawford Counties (part of loc. 1, p. 1949) 

were cited as the most complete and typical section of 

the Cane Hill. This section is hereby designated as 

the type for the member. Here, the Cane Hill consists of (a) a basal limestone conglomerate lying unconformably on the top of the Pitkin Limestone, 

(b) finely lamellar dark, shaly siltstone and claystone, 

and (c) alternating shaly sandstone and siltstone 

changing upward into increasingly flaggy, ripplemarked sandstone bearing Oonost?:chus Lesquereux and 

abundant arthrophycid burrows. The common boundary of the Cane Hill and Prairie Grove is here defined 

as lying at the base of the lowest massive, bench-forming calcareous sandstone unit of the Prairie Grove 

Member about 65 feet above the top ·of the Pitkin 

Limestone. In this type section the Cane Hill seems 

to intergrade with· the P~airie Grove_ Member. In ·the 
D40 GEOLOGICAL SURVEY RESEAHCH 1 9 6 2 

r~tvine about a third of a mile north from this type 

section, the Prairie Grove lies directly on the Pitkin. 

From the possible explanations that were cited by 

Hen best ( 1953, p. 1949) for the absence of the Cane 

I-Iill at this locality, an intraformational unconformity 

or channeloid contact was adopted with some doubt. 

Restudy suggests that truncation by creep deserves 

more consideration than originally thought. 

The Prairie Grove Member of the Hale Formation 

was described and named by Henbest (1953, p. 1940) 

from characteristic sections in the mountains around 

the Prairie Grove community, Washington County. 

The Prairie Grove Member probably includes most or 

all of the sandstone part of the "Washington Shale 

and Sandstone" of Simonds ( 1891, p. 75). It also 

includes a part, locally, of the rocks identified by 

Simonds and later authors as the "Pentremital" or 

Brentwood Limestone, but does not include any part 

of the Brentwood Limestone Member of the Bloyd 

Formation as restricted by Henbest (1953). 

The type section of the Prairie Grove Member is 

hereby designated as the section in the hillside mid 

canyon along State Highway 59 in the Elj2 sec. 35, 

T. 13 N., R. 33 vV. The type section of the Prairie 

Grove is contiguous with that of the Cane Hill Member and the area of exposure extends northward to 

the head of the canyon near the mountain pass. This 

locality is in and near the southwest corner of Washington County, 2 to 3 miles east of south along Highway 59 from Evansville and 3 to 4 miles west of south 

fron1 Hale 1\tlountain. The type sections of the Cane 

Hill and Prairie Grove Members are the same as localities 1 and 2 of Hen best ( 1953, p. 1949). The top of 

the Prairie Grove at this locality is drawn at the base 

of the first shale bed, 2 feet or more thick, above the 

uppermost massive, honeycombed ( arthrophycid) calcareous sandstone of the Prairie Grove Member. 

BLOYD FORMATION 

The Bloyd Formation was described and ·was .named 

after Bloyd ~1ountain by Purdue (1907, p. 3). A type 

area was not specified. The section in the southwest 

part of Bloyd Mountain extending from the center of 

the Elj2 sec. 3 to the center, north side of sec. 4, 

T. 14 N., R. 30 W., is hereby designated as the type 

section of the Bloyd Formation. 

The name Brentwood Limestone, now classed as a 

member of the Bloyd Formation, was substituted by 

Ulrich ( 1904, p. 109) for the name "Pentremital Limestone" of Owen (Owen, Peter, and others, 1860, p. 

115), Simonds (1891, p. 83), and others. This member was named from Brentwood Station (now deserted), but a type area was not delimited, as was the 

custom of the time in that type areas were loosely construed. The top of the Brentwood is exposed in the 

riverbed at Brentwood Station and in cuts along the 

railroad to the north, but the exposures are so incomplete or are so deeply involved with creep that they 

. comprise poor standards of reference. FortunatelJ·· 

the most complete, fossiliferous, and characteristic 

section of the Brent·wood Limestone Member is exposed near Brentwood in the cut on the east side of 

U.S. Highway 71 and the vVest Fork of "Thite River, 

from a tenth to a· half mile south of the mouth of 

Mill Creek. This section is in the center of the Nlj2 

sec. 16, T. 14 N., R. 30 "r. As previously restricted 

and defined by Hen best ( 1953, p. 1943), the Brentwood 

at this locality is 40 to 45 feet thick, contains an 

18-foot dark shale at the base, and terminates above 

in a marine limestone unit. The top of the Brentwood is truncated by an unconformity beneath the 

basal conglomerates and plant-bearing shaly sandstone 

of the Woolsey Member. The Brentwood Limestone 

and limestone facies of the Prairie Grove have been 

confused at many localities. The type locality herein 

specified was chosen as the primary standard of reference for definition of the Brentwood and for locating 

the common boundary of the Hale and Bloyd Formations. 

The Woolsey Member of the Bloyd Formation was 

named by Hen best ( 1953, p. 1943) after characteristic 

exposures near Woolsey Station. The section on the 

south and west side of Bloyd Mountain from the 

center, Elj2 sec. 3 to the center, north side, sec. 4, 

T. 14 N., R. 30 W., is hereby selected as the type section. The Woolsey ~1ember is composed of terrestrial 

· rocks. The sequence consists, beginning at the base, 

of (a) a local conglom~rate containing detritus derived from the preceding Brentwood, rarely with 

quartz gravel or with shaly sandstone and siltstone 

bearing impressions of aerial parts of plants, (b) fossil soil below the Baldwin coal (c) Baldwin coal, and 

(d) terrestrial shale ( 0-13 feet thick) with coal 

stringers and aerial parts of plants. The Woolsey 

sequence terminates at the angular unconformity beneath the marine conglomeratic ca prock of the Baldwin coal. The coal bed in the vVoolsey was named 

the Baldwin coal by Croneis (1930, p. 87) after Baldwin Station, near the area formerly mined in R-obinson Mountain, Washington County. 

The l{essler Limestone Member was described and 

named by Simonds (1891, p. 26, 103-105) from its 

"* * * * occurrence in J{essler Mountain * * * high 

up on the slope * * * in 16 N. 30 W." J{essler ~1ountain is in R. 31 W., not R. 30 W. Two limestones 
ARTICLE 130 D41 

(including the highly variable cnprock of the Baldwin coal) occur "high up on the slope" of I\:essler 

:Mountain. The upper and most consistently calcareous bed was designated by l-Ien best ( 1953, p. 1944-

1945) as t.he true l(essler. Simonds' description of the 

](essler indicates that in a few other localities the 

caprock of the Baldwin coal was misidentified as the 

l(essler. Those horizons may have been confused in 

the type urea that he designated, but at most localities 

in 'Vnshington County it is evident that Simonds 

identified the l(essler as the relatively pure, commonly 

oolitic, locally exfoliating limestone, 60 to 90 feet above 

the Baldwin coal. The "conglomeratic" appearance, 

which he noted as an identifying mark of the Kessler, 

is produced by algal-foraminiferal concretions, namely 

Osagia and Ottonosia both of Twenhofel, 1919. In a 

few places, subsequent authors have likewise confused 

the l(essler and the caprock of the Baldwin coal, but 

in general all have agreed on its identification. 

To clarify and stabilize an accepted usage, the section of the l(essler on the west side of a shallow saddle 

near the north end of the highest part of the l(essler 

:Mountain ridge, where erosion has removed the caprock (Greenland Sandstone ~1ember of the Atoka Forrnation), is hereby ·designated as the type locality of 

the l(essler Limestone ~1ember of the Bloyd Formation. This locality is near the center, SE14 sec. 25, 

T. 16 N., R. 31 ,V. The J(essler Limestone Member 

here is 5 to 15 feet thick. It forms a low bench, locally 

shows exfoliation, has an abundance of Ottonosia 

Twenhofel, 1919, and Osagia Twenhofel, 1919, in the 

upper part. The J(essler lies 22 feet below the base 

of the Greenland Sandstone ~1ember, which caps J(essler ~1ountain, and lies 70 feet above the dark-brown 

calcareous sandstone caprock of the Baldwin coal. 

ATOKA SERIES, PENNSYLVANIAN 

The Greenland Sandstone ~1ember of the Atoka 

Formn,tion was named by Henbest (1953, p. 1946-1947) 

from characteristic exposures in the mountains near 

Greenland, '~Tashington County. From the characteristic sections originally cited, the section in the 

southwest face of Bloyd Mountain in the N"V14 sec. 3 

and Ny2 sec. 4, T. 14 N., R. 30 "V., is hereby designated 

ltS the type section of the Greenland Sandstone ~1em· 

her of the Atoka Formation. 

REFERENCES 

Adnms, G. I., nnd Ulrich, E. 0., 1905, Description of the Fayetteville quadrangle, Arkansas-Missouri: U.S. Geol. Survey Geologic Atlas, Folio 119, 6 p., 2 figs., topog. map, 

geol. map, table. 

Croneis, C. G., 1930, Geology of the Arkansas Paleozoic area, 

with especial reference to oil and gas possibilities: AI·-

kansas Geol. Survey Bull. 3, 457 p., 30 figs., 45 pls., maps, 

tables. 

Giles, A. W., and Brewster, E. B., 1930, Hale Mountain section in northwest Arkansas: American Assoc. Petroleum 

Geologists Bull., v. 14, p. 121-138, 2 figs. 

nirty, G. H., 1905, The relations of some Carboniferous faunas: 

Washington Acad. Sci. Proc., v. 7, p. 1-26. 

Henbe~t. L. G., 1953, Morrow Group and lower Atoka Formation of Arkansas : American Assoc. Petroleum Geologists 

Bull., v. 37, p. 1935-1953, 2 figs. 

Lesquereux, L., 18GO, Botanical and paleontological report of 

the Geological Survey of Arkansas, p. 295-319, 6 pis., ·in 

Owen, D. D., Peter, R., and others, Second report of a 

geologieal reconnaissance of the middle and southern 

counties of Arkansas ... 1859 and 18GO: Philadelphia, 

C. Sherman & Son, 433 p., 19 pls., woodcuts, 2 maps, 

tables. 

Mather, K. F., 1915, The fauna of the Morrow Group of 

Arkansas and Oklahoma: Denison Univ. Sci. Lab. Bull. 

V. 18, p. 59-284, 16 pl. 

Owen, D. D., Elderhorst, W., and Cox, E. T., 1858, First re .. 

port of a geological reconnaissance of the northern counties of Arkansas made during the years 1857 and 1858: 

Little Rock, Ark., Johnson & , Yerkes, 256 p., 10 pls. 

(listed), woodcuts, columnar sections, tables. 

Owen, D. D., Peter, R., Lesquereux, L., and Cox, E. T., 1860, 

Second report of a geological reconnaissanee of the middle 

and southern counties of Arkansas ... 1859 all(l 1860: 

Philadelphia, C. Sherman & Son, 433 p., 19 pls., woodcuts, 

2 maps, tables. 

Purdue, A. H., 1907, Description of the Winslow quadrangle, 

Arkansas-Indian Territory: U.S. Geol. Survey Geol. Atlas, 

Folio 154, 6 p., topog. map, geol. map, columnar section, 

4 figs. 

Purdue, A. H., and Miser, H. D., 1916, Description of the 

Eureka Springs and Harrison quadrangles, ArkansasMissouri: U.S. Geol. Survey Geol. Atlas, 1J'olio 202, 21 p., 

2 topog. maps, 2 geol. maps, 9 pls., 13 figs., coh.1mn:u· section, 8 structure sections, 2 tables. 

Simonds, F. W., 1891, The geology of Washington County: 

Geol. Survey Arkansas Ann. Rept. 1888, v. 4, pt. 1, 154 p., 

2 pls., unnumbered pls. and figs., geol. map. 

~raff, J. A., 1905, Description of the Tahlequah quadrangle, 

Indian Tel'l'itory---;Arkansas: U.S. Geol. Survey Geol. Atlas, l!_,olio 122, 7 lp., 2 figs., topog. map, geol. map, columnar section, structure section, tables. 

Ulrich, E. 0., 1904, Determination and correlntion of formations, in Adams, G. I., Ulrich, E. 0., and others, Zinc and 

lead deposits of northern Arkansas: U.S. Geol. Survey 

Prof. Paper 24, p. 90-113. 

White, C. David, 1895, Tile Pottsville Series along Ne"; Rive1·, 

West Virginia: Geol. Soc. America Bull., v. 6, p. 305-320, 

2 figs., 2 tables. 

-- 1900, The stratigraphic succession of the fossil floras 

of the Pottsville Formation in the southern anthracite 

coal field, Pennsylvania: U.S. Geol. Survey 20th Ann. 

Rept. pt. 2, p. 749-930, pls. 180-193. 

Wilmarth, 1\f. G., 1938, Lexicon of geologic names of the 

United States: U.S. Geol. Survey Bull. 896, 2396 p. 
D42 GEOLOGICAL SURVEY RESEAR'CH 19 6 2 

131. NEW MEMBERS OF THE BLOYD FORMATION OF PENNSYLVANIAN AGE, WASHINGTON 

COUNTY, ARKANSAS 

By LLoYD G. HENBEST, Washington, D.C. 

The Bloyd Formation is the upper of two formations of the Morrow Series at its type locality in 

Washington County, Ark. The Brentwood Limestone 

Member (Ulrich, 1904), l(essler Limestone Member 

(Simonds, 1891), and the Woolsey Member (Hen best, 

1.953) were named during previous studies of the Morrow Series. Two marine shale members, which constitute two-thiTds of the Bloyd sef]Uence, remained unnamed. 

In a field conference in 1961 with H. D. Miser and 

M. Gordon, of the U.S. Geological Survey, and with 

J. H. Quinn, University of Arkansas, it was agreed 

that the two shale members are mappable and useful 

in describing the geology of Washington .County and 

that this writer would both name ·those two unnamed 

members and designate type sections for the previously 

named units of the ~{orrow. 

The lithic composition, stratigraphic relations, and 

sedimentary structures of the Morrow Series are indicated in figure 131.1. 

DYE SHALE MEMBER 

The rocks of the Bloyd Formation that lie between 

the top of the terrestrial 'Voolsey Member and the 

base of the l(essler Limestone 1\-fember are here named 

the Dye Shale Member from a characteristic development in Bloyd Mountain, whose sides are partly 

drained by Dye Creek. The type locality of the Dye 

~{ember is here designated to coincide with the type 

locality of the Bloyd Formation as designated in 

Article 130; that is, from the EV2 sec. 3 to the center 

of the north side of sec. 4, T. 14 N., R. 30 W. 

The Dye Shale Member is widely distributed and 

mappable in Washington County. The Dye and the 

Trace Creek Shale Members are similar in composition. They are poorly exposed and are identified 

chiefly by their position relative to the 'Voolsey and 

the l(essler Members which have marked, lithic features. The extension of the Dye Shale ~{ember westward into Oklahoma has not been determined because 

the bracketing units change into indistinct units. 

Rapid lateral changes east~ard, in the area where 

the Morrow has been removed by the White River, 

have introduced complications in tracing the Dye 

Shale Member as well as other Morrow units eastward 

from Washington County. With the exception of 

fossils and of the coal bed, no lithic property or 

bedding structure in the Morrow Series or in the 

adjacent parts of the Atoka Series of Washington 

County is known to be exclusively characteristic of 

the unit in which it is found. 

Especially good exposures of the Dye Shale Member, 

besides the type locality, are those in the hillside and 

railway cuts at the south edge of Brentwood, in the 

northeast part of Fayetteville in the SW%,NE14SW14 

sec. 10, T. 16 N., H. 30 ,V., and in slopes around Mount 

Sequoyah (formerly East Mountain) , on the east side 

of Fayetteville. 

The Dye Shale Member is 60 to 110 feet thick. 

l1y far the greater part of the member consists of 

dark-gray to black shaly siltstone and claystone. Thin 

lenticular limestone beds and calcareous zones are 

present here and there. Most of these are definitely 

recognizable as of marine origin. The remainder of 

the unit appears to be marine. The organic-matter 

and sulfide content of the Dye is rather low at most 

places. Deposition· in shallow, rather poorly circulated, muddy sea water is evident. 

The basal unit of the Dye Shale Member is informally called the "caprock of the Baldwin coal" by 

the writer. The caprock is widely distributed in 

Washington County. The caprock and the Baldwin 

coal in the underlying Woolsey Member are the most 

consistent and easily recognized markers in the Morrow 

Series of Washington County. The caprock ranges 

from 0 to 25 feet in thickness. It is conglomeratic; 

commonly consists mainly of calcareous sandstone; 

locally contains quartz gravel up to 14 mm across; 

commonly crossbedded; contains marine fossils; and 

commonly lies with erosional discordance on the underlying terrestrial beds of the Woolsey Member. It 

'Yas the basal sediment of an advancing sea. The chocolate color of .the caprock is a result of chemical 

weathering by acid from oxidation of sulfides in the 

underlying Baldwin coal and should not be interpreted as a deposit of subaerially weathered, reworked 

limestone. The caprock of the Baldwin coal has been 

confused at many localities with the Kessler Limestone 

Member by earlier workers. 

'Vith the exception of the caprock of the Baldwin 

coal, the Dye Shale l\1ember generally forms a subdued 

topographic surface. Though the mineral composition 

of the Dye is favorable. for soil formation, its impervi-
r:: 

8 0 

fB ·.p 

.s ·s:: CIS 

~ Member Composite 

section 

ARTICLE 131 D43 

Description J5 E r:n 0 

en 

= e 

~ 

·= 

~ ~ 

0 

s:: 

~ 

·= ~ 

> 

~ s:: 

s:: 

Q) 

0-4 

~ 

CIS CIS ..!od ..!od 

.s .s 

< < 

Greenland 

Sandstone 

a b c '\1( 

Ill Siltstone, shaly, sandy, variable 

·-· - ·-·-·-·-·-·-· Sandstone, bedding sheety to coarsely shaly, ripple marks prominent; forms 

t~.~-.;.~.··.·:~=.··-~·~;_:·•.: ;~-.·.··_: ~~· .. ·:_._:· .. -.·_.-:-_·:·":_.=_. ·-. ·_:_~.~--~·:· continuous bench or cliff. Locally massive. Local lenses of calcareous sand- -~ ... stone. Contains quartz gravel and marine fossils including Taonurus 

~:.~:;.:,.: ~·.:.:.·: .~:·..:.:.·. ':":": :~ "": colletti?, Scalarituba sp., and cephalopods. Shallow marine environment 

t---t---t----------"t-;;;.' ;:'· :::··-::· ·.~··=·-=· ·=·-:::· ~-::: :,...::·::··~:.;J.'t';;:·: -;:: :1~·-.~··:J.:.i:,-~;;L.~· ·=:::jk-'-<::: Contact commonly channeloid to interfingering 

:=--- -~-= 

1 

EQ 

~ 

~ 0 

~ 

Trace Creek 

Shale 

~ . . . . .. ....: Siltstone and claystone, shaly, medium-gray to black; local lenses of limestone 

~----==-_-== with marine fossils 

1---::..._,._~--- ;_ ~-=- Sandstone or limestone locally comprises basal bed of member. Limestone 

r::=:-- _ - composed of chocolate-colored redeposited detritus :-:r:-r. :r.z -

~ --=-==---=-= ,...._ - Contact channeloid(?) 

~------------------·[~~~~1:~~==- == ~i A·.·:::.·.·.·::::::.·. 

1-J,..I,..I,..,..,..,.. ~ 

Limestone, marine, oolitic, medium- to light-gray, locally weathers with 

exfoliation; algal-foraminiferal concretions of Ottonosia and Osagia char- Kessler acteristic; locally glitters with secondarily enlarged sand grains 

Limestone 

Dye Shale 

Caprock of the 

Baldwin coal 

Baldwin coal 

Woolsey 

Brentwood 

Limestone 

Prairie Grove 

Cane Hill 

L• • ·.I· • • I • • ·.1· • ·.1·• ·J • E.-- :.::: - ·_--·1·•·1::·.14.: -...:- X X X Jl X .,._ ell'X JL .A. 

Siltstone and claystone, shaly, medium- gray to black; local lenses of limestone with marine fossils 

Sandsto.ne, limestone, and conglomerate, commonly crossbedded, locally 

channeloid; includes quartz gravel, coalified wood; brown to chocolate 

colored; marine fossils. Intertongues with the Dye Shale Member 

Vunconformity 

Siltstone, shaly, terrestrial, contains parts of plants and coal stringers 

Coal, rarely thicker than 14 inches 

__ L::·.-: :::·~ ;..----~~~-:-~=~----~= 

~ ~,·~~~~ ~~::::il~::s:~n:::n:~::~:n: sheety; terrestrial; plants abundant 

~--J--1--1- I I \'unconformity 

... .'~--.: -~ '-A-1-te_r_n_a_t-in_g_li_m_e_s-to_n_e_a_n_d_s_h_a_le-.--L-im_e_s-to_n_e_b-ed-s-le_n_t-ic_u_l_ar-,-c-o_a_le_s_c_in-g-to--1 

massive units. Marine, foasiliferous, Pentremites locally abundant 

----==---~ fJ .. J.~J .. J+J ...... · ',.', 0 0. • ... •• ·:-:. 0 

J-J ·J··J .. I·J .. JJ:;.'·:;...-.,:-::.:::~:·,_.:~r-::­

·J· .J-J1-J .. J·l j. -~;i::>:.i: :--~.-r.::. .. ;t~··. 1· I 

J·J·N .. J+J .. J·IJ::.:.-:;r::::t;..::_k:~l 

~-J+J·J·IJ·-J-1 J·J·I~· :::.:1=-:::-:·.t:: ::.]::-. 

J·J.-tJ .. J·I·J·J-1-J· Jf;.:·: :: ::·:.1::: :: ;F ~ .. IIIII 

J · J·I·J·JN·J+J .. J·:I:: . .-:.:.:1~:: ~: :.r · ~-J- •J•J•I•J•J•+JooJ~: ~o :~·.:.t:::. 

Limestone and sandstone, individual beds and unit vary laterally from lime· 

stone to calcareous sandstone. Sandy facies commonly honeycombed with 

burrows of Arthrophycus-like animal. Conspicuously crossbedded, locally 

oolitic; secondary enlargement of sand common. Nearshore marine. 

Abundantly fossiliferous 

··.~j' ... j ... J:.~~~""'·~-!t~-~~---------------------1 ~·.::::::~ ~Contact channeloid, locally intertonguing 

1---+---1----1"-----------,......:~ .. - .. - .. -~.::::~~ Siltstone and sandstone, sha:ly to sheet-bedded, prominently ripple marked; 

~~~.·=·.--:.~·:_· ~· .. -::~.·-~:· ... · .. -:·.·1

1 1

1 

1 sheds hard wafers of sandstone into hillside soil. Lenses of marine sand· 

Pitkin Limestone 

Fayetteville Shale 

~: . ~ . , .. ,. stofle and clay-pebble conglomerate in lower part, containing redeposited 

I I \' -- -~ I .1 Pitkin Limestone. Locally coalified wood, rock-boring pelecypods(?), and 

I I - -.::..,:.::::._ 1 1 faunule consisting principally of Hustedia miseri 

-._ - - Unconformity representing gap of considerable Late Mississippian and Early 

Pennsylvanian time 

Limestone, pure, medium· to light-gray, commonly oolitic; forms cliffs; source 

of rich soil; characterized by indigenous Archimedes; commonly cavernous 

FIGURE 131.1.-Composite section of Morrow Series and adjacent rocks in Washington County, Ark. Topographic expression of 

rock units is shown on left side of column: a, forms .prominent cliffs or rock-controlled surfaces; b, forms local cliffs or benches; 

ttnd c, forms subdued surfaces. Vertical scale, 1 inch equals approximately 60 feet. 

654685 0-62-4 
D44 GEOLOGICAL SURVEY RESEARrCH 1962 

ousness to water and consequent low storage and 

circulation capacity promotes excessive drying during 

droughts-. This generally results in poor vegetation 

cover or scrubby forest with glades, rapid erosion, 

and poor soil. 

Fossils are scarce in the Dye Member. It is dated 

as of late Morrow age chiefly by its stratigraphic 

position. It directly overlies the well-known floral 

zone of the Baldwin coal of late middle or early late 

Pottsville age (White, 1895, 1900) and overlies the 

faunal zone of the Brentwood Limestone Member 

fauna, both of which are middle Early Pennsylvanian 

age. It underlies the I\:essler Limestone Member, 

whose fauna is related to the Morrow assemblages 

(Ulrich, 1904, p. 110; Girty, 1905, p. 8; Mather, 1915, 

p. 67). 

TRACE CREEK SHALE MEMBER 

The rocks that lie between the top of the Kessler 

Limestone_ Member of the Bloyd Formation and the 

base of the Greenland Sandstone Member of the Atoka 

Formation are here named the Trace Creek Shale 

Member of the Bloyd Formation. The member is 

named from its development in Bloyd Mountain, 

whose slopes are partly drained by Trace Creek. Its 

type locality is here designated as congruent with that 

of the Bloyd Formation; that is, the southwest part 

of Bloyd Mountain from the center of the_ Elj2 sec. 3 

to the center of the north side of sec. 4, T. 14· N., R. 

30 w. 

The Trace Creek Shale Member is widely distributed 

and mappable in 'Vashington County. Though the 

Trace Creek Member probably extends bot.h westward 

into the edge of Oklahoma and eastward from Washington County, its extensions outside· Washington 

County are obscured by lateral changes in the Morrow 

Series. Besides the type locality, two especially characteristic exposures of the Trace Creek are found at 

the type locality of the Kessler Limestone Member 

near the center of the SE1,4 sec. 25, T. 16 N., R. 31 W., 

on the west side of a saddle formed by an· erosional 

gap in the Greenland Sandstone Member of the Atoka 

Formation, which caps J(ess]er l\1ountain. This saddle 

is on the crest and near the north end of Kessler 

Mountain. The other locality is a half mile southeast 

of Brentwood Station. The localities cited above as 

characteristic for the Dye Shale Member are equally 

informative for the Trace Creek Shale Member. 

The Trace Creek Shale Member is composed of 

marine dark-gray to black shaly siltstone and claystone with minor local, thin, calcareous zones, and 

limestone or calcareous sandstone lenses. Its thickness is generally 60 to 70 feet, but at the J(essler 

Mountain exposure cited above it is only 20 feet thick 

beneath the quartz gravelstone conglomerate of the 

Greenland Sandstone l\fember of the Atoka Formation. 

The maximum thickness of about 125 feet so far recognized is near the southwest corner of Washington 

County. The Trace Creek generally forms a subdued 

surface. It is impervious and commonly forms a 

poor soil with limited vegetation cover and. scrubby 

forest with glades. 

The Trace Creek Shale Member locally intergrades 

with the underlying J(essler Limestone Member. At 

some localities, however, the basal beds consist of 

medium-textured sandstone or chocolate-colored redeposited limestone derived from the J(essler. The 

stratigraphic relations with the Atoka vary :from 

angular erosional contact with the Greenland Sandstone Member to possibly an interfingering with-Atoka 

sediments. The Trace Creek has yielded few fossils 

and its age is determined principally by its position 

beneath the Atoka Series of Middle Pennsylvanian 

age and above the faunal zone of the Kessler Limestone Member of ]ate Morrow age. 

REFERENCES 

Girty, G. H., 1905, The relations of some Carboniferous faun:uo~: 

Washington Acad. Sci. Proc., v. 7, p. 1.:...26. 

Henbest, L. G., 1953, Morrow Group and lower Atoka Formation of Arkansas: Am. Assoc. Petroleum Geology Bull., 

v. 37, p. 1935-1953, 2 figs. 

Mather, K. F., 1915, The fauna of the Morro'v Group of Arkansas and Oklahoma: Denison Univ. Sci. Lab. Bull., v. 

18, p. 59-284, 16 pl. 

Simonds, F. W, 1891, The geology of Washington County: 

Geol. Survey Arkansas Ann. Rept. 1888, v. 4, pt. 1, 154 p., 

2 pls., unnumbered pls. and figs., geol. map. 

Ulrich, E. 0., 1904, Determination and correlation of formations, ·i-n Ad:uns, G. 1., Uli·ich, ID. 0., Purdue, A. H., and 

Burchard, E. H. Zinc and lead deposits of northern Arkansas: U.S. Geol. Survey Prof. Paper 24, p. 90-113. 

White, D. David, 1895, The Po_ttsville Series along New River, 

West Virginia: Geol. Soc: America Bull., v. 6, p. 305-320, 

2 figs., 2 tables. 

-- 1900, The stratigraphic succession of the fossil floras 

of the Pottsville Formation in the southern anthracite 

coal field, Pennsylvania: U.S. Geol. Survey 20th Ann. 

Rept. pt. 2, p. 7 49-930, pls. 180-193. 
ARTICLE 132 D45 

132. THE EAGLE VALLEY EVAPORITE AND ITS RELATION TO THE MINTURN AND MAROON FORMATIONS, 

NORTHWEST COLORADO 

By T. S. LovERING n.nd ,V. ''T· l\1ALLORY, Denver, Colo. 

R.egional paleogeographic maps (Mal\ory, 1960, fig. 

5) show that in Pennsylvanian and Early Permian 

time two .elements of the ancestral R.ocky Mountains, 

the l.Jncompahgre and the Front R.ange highlands, 

dominated the geography of Colorado. Between them 

was a basin of deposition, now called the Eagle or 

Mn.roon basin by local geologists, which is separate 

from the analogous Pn.radox basin of equivalent age 

on the southwest side of the Uncompahgre highland. 

The l\1inturn quadrangle, in which this study was 

1nade, is on the northeast flank of the Eagle (or 

l\1nroon) basin (fig. 132.1). 

l\1ost of the sedimentary rocks exposed in the Minturn quadrangle are of Pennsylvanian and Permian 

age. Conrse clastic rocks dominate the sequence, but 

siltstone n.nd carbonate rnarker beds are common, and 

an evaporite section is present in the northwestern 

part of the quadrangle. The relation of the clastic 

sequence to the evaporite facies has posed a problem. 

T'wo :formations, the l\1inturn and the Maroon, comprise the coarse clastic facies. The Minturn Formation, about 6,000 feet thick (Tweto, 1949, p. 204), is 

primarily gray, tan, and dull maroon shale, sandstone, 

grit, and coarse conglomerate; shale is more abundant 

in the upper part. A few dolomite beds occur in the 

lower part of the formation, many limestones in the 

1niddle, and a few limestones in the upper part. Many 

of the carbonate beds abruptly change lithology along 

strike from nearly pure carbonate to grit or other 

clastic rocks containing little or no carbonate. Many 

of the limestones in the middle of the :formation a 

few miles southeast of the town of Minturn contain 

porous dolomite reefs many times thicker than the 

bedded limestone a short distance away. At least 

the ]ower five-sixths of the l\1inturn Formation is of 

Des l\1oines age (Tweto, 1949, p. 205-206) as deterlnined by the presence of abundant fossils in the thin 

limestone beds. 

The overlying l\1aroon Formation, about 2,000 feet 

thick, :is s:irnilar to the l\1inturn in lithology but contains much more siltstone. Its bright brick-red color 

contrasts with the dull purplish-red and grayish-tan 

colors of the l\1inturn. Except for some long-ranging 

plants, no fossils have been found in the l\1aroon 

Formation in the l\1inturn quadrangle, but its age is 

inferentially Pennsylvanian and Permian because it 

lies conformably upon the l\1inturn Formation of 

Des l\1oines and younger age and is overlain by the 

Chinle Formation of Late Triassic age (Lovering and 

T"·eto, 1944, p. 50). 

Of critical significance in disting~1ishing the Minturn 

from the l\1aroon is the Jacque Mountain Limestone 

l\1ember, designated by Tweto (1949, p. 204) as the 

uppermost .member of the l\1inturn Formation. At its 

type locality on Jacque l\1ountain, 23 miles southsoutheast of section J1 of this article (fig. 132.1D), 

the unit is 21 feet thick; at section J1 it is 27 feet 

thick. According to Tweto (written communication, 

Jan. 31, 1962) the lithology is strikingly similar in 

both localities and is divisible into three parts. The 

top 5 or 6 feet of the member at both localities is 

gray medimn-grai11ed oolitic limestone, locally sandy. 

Beneath this upper unit is a thin zone containing 

detrital material: n. 2-foot calcareous red siltstone at 

,Jacque Mounta.in, and a. 2-foot cross-bedded biotite-rich 

pinkish limestone at section Jl. The lower 20 feet 

of the member is gray limestone. The upper part of 

this lower unit is mottled pink and green, r~nd is 

locally oolitic and fossiliferous; the lower part is 

dense to lithographic. 

The lithologic homogeneity of the Jacque Mountain 

from its type locality to section J1 as· mapped by 

Lovering and Tweto ( 1944) in the Minturn quadrangle 

is in sharp contrast to the facies changes observed 

when the bed is followed westward a short distance, 

as from section J1 to section J10 (fig. 132.10). Maps 

and sections made by the writers in 1961 show that the 

27 -foot thickness of the Jacque l\1ountain Limestone 

Member at section J1 thickens to about 140 feet of 

strata of equivalent age but dissimilar lithology at JS 

(the entire measured interval at JS). From section J1 

to section JlO, the Jacque Mountain Limestone l\1einber splits into discrete tongues, and terminates a short 

distance west of J10. Many of the tongues thicken 

locally into small reefs or banks near their terminus 

in the evaporite· facies (fig. 132.10). 

Because the Maroon and Minturn Formations have 

similar lithology, it is essential in mapping them that 

the Jacque Momitain Limestone l\1ember or its recognizable equivalent be present. Fortunately, the 

member is easily traced in the Minturn quadrangle except in the northwestern part where the Jacque Mountain terminates in the evaporite sequence. ·Murray 

( 1958, p. 52, and fig. 2) has indicated that the evaporite sequence exposed in the valley of the Eagle 

R.iver between l\1inturn and ';y olcott is equivalent in 
D46 GEOLOGICAL SURVEY RESEARCH 19 6 2 

JlO J9 J8 

c 

-----------, 

.DENVER 

A 

I 

I 

' I 

I 

I 

I 

I 

' I 

I 

\ 

I 

I 

\ 

I __ _J 

J7 J6 J5 

0 

APPROXIMATE SCALE 

150 FEET 

100 

50 

0 

VERTICAL 

SCALE 

2 MILES 

FIGURE 132.1.-A, Map of Colorado showing major paleogeographic 

features for Pennsylvanian time and location of the Minturn quadrangle, the Champlin No. 1 Black well, and Jacque Mountain. B, 

Part of the Minturn quadrangle, showing location of the measured 

sections. C, Stratigraphic section illustrating interrelation of the 

Eagle Valley, Maroon, and Minturn Formations, and .Jacque Mountain 

Limestone Member of the Minturn Formation in the vicinity of 

Minturn, Colo. Actual measured intervals are shown by vertical 

lines; horizontal extensions of the section between and beyond measured 

intervals are reasonable interpolations consistent with general stratigraphy observed in the field. D, A small section with little vertical 

exaggeration ·showing regional variation in thickness of the Jacque 

Mountain Limestone Member. 
ARTICLE 132 D47 

E·X P LA N AT I 0 N 

Carbonate rock 

hin-bedded to massive gray to block dense 

limestone; locally dolomite. Algol remains 

common 

Gypsiferous mudstone 

Frequently silty; light shades of yellow gray, 

green, tan, or pink 

r::: :.;:~~:JI 

Reefoid carbonate rock 

Porous to vuggy, in irregular beds with 

rubbly upper surface 

1·:.:.;:~:.;.~:::·.~:/:~::~j 

Grit' and sandstone 

Red, maroon, or rust 

!·····.,, .. , .... , ..... , 

Ia axs a *I Sandstone marker bed 

Fine- to medium-grained; rounded 

Biotitic limestone 

~ E---"3 

Black paper shale 

Bedded gypsum_ 

J3 J2 

c 

8 MILES .Jl 23 MILES 

limestone bed 

D 

age only to beds contained within the Minturn Formation, but field study shows that bedded gypsum and 

gypsiferous mudstones of the evaporite sequence intertongue with parts of both the ~iaroon and Minturn 

Formations. Because the Minturn and the Maroon 

Formations are not distinguishable as cartographic 

units in the evaporite sequence, the name Eagle Valley 

Evaporite is here proposed for the gypsiferous sequence exposed in Eagle Valley of the Eagle River 

in the vicinity of A von, Colo. The sequence extends 

from Tracer Creek about a mile northwest of the 

mouth of Gore Creek, to Red Canyon about 9 miles 

west-north west. 

B 

Jl 

Red siltstone parting 

. ' 

Jacque 

Mountain 

The type section is established as measured sections 

JS and .J9 on the interfluve west of Nottingham Creek, 

north side of Eagle River, in sees. 6 and 7, T. 5 S., 

R. 81 W., Eagle County, Colo. The Eagle Valley 

Evaporite in this area is predominantly gypsiferous 

mudstone and siltstone, usually light colored, which 

contains bedded gypsum and a .few cherty dark gray 

limestone beds about 1 foot thick. Also included 

are beds of reddish shale and siltstone. The formation 

forms smoothly rounded slopes partly covered by a 

veneer of slump detritus owing to the soft, easily 

weathered character of the rock. The topographic 

expression and color of the Eagle Valley Evaporite 
D48 GEOLOGICAL SURVEY RESEARCH 19 6 2 

contrasts strongly with the brighter colors and massive ledges of the Minturn and Maroon Formations 

into which it tongues. At the type locality the lower 

part of the formation is covered by alluvium of the 

Eagle River, and the upper part is in brush or aspencovered slopes where its contact with an overlying 

tongue of Maroon Formation is obscure. Farther west 

the gypsiferous sequences are thicker, contain more 

bedded gypsum, and may have a definite top and base, 

but the type area is chosen near Avon because here 

the age and the relation of the Eagle Valley Evaporite 

to the Maroon and Minturn Formations and the 

Jacque Mountain Limestone Member .can be demonstrated. 

In Red Canyon, red gypsiferous siltstone beds of 

the Eagle Valley Evaporite are conformably overlain 

by the Chinle Formation of Triassic age; the siltstones merge with the uppermost Maroon Formation 

to the northeast and lie upon dull-colored or gray 

gypsiferous mudstones and bedded gypsum. 

The Eagle Valley Evaporite dips west at Red 

Canyon and extends an indefinite distance west and 

northwest into the central part of the Eagle basin. 

Near Eagle, Colo., about 16 miles west of Avon, 4,700 

feet of evaporite-bearing rocks occur in a well, the 

Champlin No. 1 Black (sec. 4, T. 5 S., R. 84 W.). 

These rocks are anhydritic gypsiferous mudstone and 

siltstone with abundant halite casts and some bedded 

halite. At the surface the rocks are red gypsiferous 

clastics that have been identified as the Maroon Formation. Evaporite-bearing strata are present from 

the surface down to the top of the Belden Shale, 

which regionally underlies the Minturn Formation. 

Evidence in the Black well and at Red Canyon therefore suggests that west of the type area the Eagle 

Valley Evaporite is the time equivalent of all of the 

Minturn Formation and much of the Maroon ForInation. 

The regional evidence indicates that while coarse 

clastics of the l\1int.urn and l\iaroon Formations were 

being deposited near the shores of the trough by 

waters ranging ·in salinity from fresh or brackish to 

normal marine, salts of the Eagle Valley Evaporite 

were precipitating from supersaline brines a few 

miles offshore in more rapidly subsiding parts of the 

trough. 

REFERENCES 

Lovering, T. S., and Tweto, 0. L., 1944, Preliminary report 

with map on geology and ore deposits of the Minturn 

quadrangle, Colorado: U.S. Geol. Survey open-tile report, 

115 p. 

Mallory, W. W., 1960, Outline of Pennsylvanian stratigl'aphy 

of Colorado, in Guide to the geology of Colorado : Geol. 

Soc. America, jointly with Rocky Mtn; Assoc. Geologists 

and Colorado Sci. Soc., p. 23-33. 

l\Iurray, H. F., 1958, Pennsylvanian stratigraphy of the Maroon Trough, in Symposium on Pennsylvanian rocks of 

Colorado: Rocky Mtn. Assoc. Geologists, p. 47-57. 

'J~weto, 0. L., 1949, Stratigraphy of the Pando area, Eagle 

County, Colorado: Colorado Sci. Soc. Proc., v. 15, no. 4, 

p. 149-235. 
ARTICLE 133 D49 

133. JURASSIC STRATIGRAPHY IN THE McCARTHY C-5 QUADRANGLE, ALASKA 

By E.lVL 1\{ACKJ<JVJ~TT, tTR., a.nd R. vV. ll\ILAY, 1\{e.nlo Park, Calif., and "\Vashington, D.C. 

Previously undescribed fossiliferous Jurassic marine 

sedimentary rocks having a cumulative thickness of 

n1ore than 9,000 feet are well exposed in the McCarthy 

C-5 quadrangle, Alaska, where they were mapped by 

l\{acl(evett and M. C. Blake, Jr., during 1961. Provisional field identifications of fossils by D. L. Jones, 

of the U.S. Geological Survey, facilitated the mapping, 

and paleontologic studies by Imlay determined the 

geologic ages of the Jurassic rocks. . 

The 15- by 22Jj2 -minute l\1:cCarthy C-5 quadrangle 

is in rugged terrain having a relief in excess of 11,000 

feet on the southern flank of the "\Vrangell 1\{ountains, 

about 200 miles east of Anchorage (fig. 133.1). 

l\{offit ( 1938) , during his extensive reconnaissance 

mapping in the general region, recognized only two 

small patches of Jurassic rocks within the 1\icCarthy 

C-5 quadrangle, and he grouped most of the Jurassic 

rocks with Cretaceous rocks or with the McCarthy 

Shale of Late Triassic age. 

The nearest expose~ ,Jurassic sequence that has been 

mapped in detail is in the Talkeetna Mountains A-1, 

A-2, and B-1 quadrangles in the Nelchina area, about 

150 miles northwest of l\1:cCarthy (fig. 133.1). Grantz 

( 1960a, b) described this fossiliferous Jurassic section 

as being over 15,000 feet thick and consisting of Lower 

Jurassic submarine volcanic and sedimentary rocks, 

Middle Jurassic nea·rshore sandstone, and Upper Jurassic siltstone, sandstoile, and conglomerate. 

0 50 100 MILES 

F10um~ 133.1.-Index map of part of Alaska showing the location of the McCarthy C-5 quadrangle. 

The Jurassic rocks in the 1\icCarthy C-5 quadrangle 

consist of fossiliferous shelf strata of Early, Mid-

. die( n, and Late Jurassic age. These rocks occupy 

a belt as much as 10 miles wide that extends northwestward across the quadrangle (fig. 133.2). l\{ost 

of the rocks dip northward at low angles, but locally 

they form open folds. Faults that cut the Jurassic 

. strata commonly strike northward, are nearly vertical, 

and have apparent right-lateral displacement. 

The .J urnssic rocks consist of a conformable sequence 

that appears to overlie the McCarthy Shale of Late 

Triassic age conformably, and is unconformably overlain by Cretaceous marine sedimentary rocks or by 

Tertiary continental and lacustrine sedimentary rocks 

that are intercalated with the basal part of the Wrangell Lava. A hiatus separates the rocks of Early 

Jurassic age from younger Jurassic rocks, and other 

gaps probably occur within the Jurassic sequence 

despite the apparent conformity of the stratigraphic 

succession. 

The Lower and Middle ( ~) Jurassic strata, which 

constitute about a third of the Jurassic section, consist 

chiefly of limestone and shale. The overlying thick 

Upper Jurassic sequence consists don1inantly of shale 

but locally contains sandstone and conglomerate in its 

higher part. 

Five ,Jurassic units are delineated on the map (fig. 

133.2) , and a summary of the lithology, the indicated 

geologic age, and the stratigraphic range of the important fauna of the Jurassic rocks is shown in figure 

133.3. The lowermost of these, Jl, is composed of 

light- to medium-brown-weathering silty limestone and 

shale, contains mollusks of Sinemurian age, and overlies the evenly bedded l\1:cCarthy Shale, which weathers 

dark brown. This unit is overlain by a distinctive 

sandy and silty limestone unit, Jls, that contains 

abundant fossils of the Early Jurassic pectenid W eyla. 

Prof. S. W. Muller, of Stanford University, has examined several of the w ey las and believes that they 

are indicative of a Pliensbachian (Early Jurassic) 

age (oral communication, 1961). The unit forms 

bold outcrops and is an excellent marker that is traceable across the quadrangle. 

These Lower Jurassic rocks are locally overlain by 

reddish-brown shale and limestone, Js, that contain 

diagnostic ammonites indicative of a Middle ( ~) or 

possibly an early Late Jurassic age. 

A widespread unit composed mainly ~f shale, Jsh, 
D50 GEOLOGICAL SURVEY RESEARCH 1 9 6 2 

EXPLANATION 

Contact Fault 

Dashed where approximatel11 located Dashed where approximatel11 located 

FIGURE 133.2.-Generalized geologic map showing the distribution of Jurassic rocks in the McCarthy C-5 quadrangle. QTKs, 

Sedimentary and volcanic rocks, Cretaceous or Tertiary, and surficial deposits, Quaternary; Jsh, shale, and Jc, conglomerate, 

Upper Jurassic; Js, shale and limestone, Middle(?·) and Upper Jurassic; Jls, limestone, and Jl, limestone and shale, Lower Juras· 

sic; "'Rmc, McCarthy Shale, Upper Triassic. 
LITHOLOGY 

Mainly dark-gray shale 

Cretaceous 

or.Tertiary 

rocks 

~----

1- -Jsh - -----

1- ----=-----= 1- ----

THICKNESS 

(FEET) 

Conglomerate ~~·.~ 

ff .~ • d oj."' 0-650 ,..c:::...2.._· 0 0 c .L.....!..·~:..O. 

it--....Q__-1;- .............. '*" ~~--'-26 Interbedded conglomerate sand-~· 0 0 ~ 

stone and shale ~ •...:....J!,. ·~ t-:_: ~.--;--;-~ 

~ ................ -:::5:: 

p ~ a:>-Q:l = ~~~ 

1- -- -: 5000 

Mainly dark-gray shale that~~-.-

weathers brown, subordinate~~·­ limestone, siltstone, and lime-~--=-----:. 

stone concretions 

Red-brown shale and 

limestone 

1-~--- ----

t-- -- - 1- ,_____ ---- __ -

~-- .= silty~Js~ 0-1000 

ARTICLE 133 

APPROXIMATE RANGE OF 

CHARACTERISTIC FOSSILS 

B

J . elemnttes 

Buchia rugosa (Fisher) 

Buchia concentrica (Sowerby) 

IBuchia mosquensis (Von Buch) 

Partschiceras sp. 

IAmoeboceras (Prionodoceras) sp. 

I

Reineckeia?, Kheraiceras? sp. 

lProcerites? sp., Inoceramus 

cf. I. ambiguus Eichwald 

Ma1nly silty 11 mestone, m1norm Jls'~ 150_300 I Weyla sp., Gryphaea sp., Chlamys sp. 

r

_C£!02!lOJ!U!!i!>na._ ________ l~~~~~~---l T ICrucillobiceras sp. 

l

lEntolium(?) semiplicatum (Hyatt) 

r-=-- --- I Psiloceratacid ammonites Gray silty limestone and limestone~JI~ 1500-2300 

intercalated with dark-gray shale1~~~~~ ~ Arnioceras sp. 

1=-= ""-

McCarthy Shale 

(Triassic) 

STAGE 

Kimmeridgian and 

Oxfordian 

Early Callovian and 

Bathonian(?) 

Pliensbachian 

Sinemurian and 

Hettangian(?) 

D51 

SERIES 

Upper Jurassic 

Middle(?) and 

Upper Jurassic 

Lower Jurassic 

FIGURE 133.3.-Generalized columnar section and descriptions of Jurassic rocks in the McCarthy C-5 quadrangle. Letter 

symbols in the lithologic section are explained in the caption for figure 133.2. 

directly overlies either the shale and lilnestone unit 

(Js) or the subjacent limestone unit (Jls) with apparent conformity. It contains abundant Buchias 

n.nd a few diagnostic ammonites. Brown-weathering 

sandstone that occurs high in the upper shale unit is 

locally transitional into a pebble or cobble conglomerate, J c (figs. 133.2, 133.3). An angular unconformity 

marks the contact between the Jurassic and the Cretaceous or Tertiary rocks. 

REFERENCES 

Grantz, Arthur, 1960a, Geologic map of Talkeetna Mountains 

(A-2) quadrangle, Alaska, and the contiguous area to the 

north and northwest: U.S. geol. Survey Misc. Geol. Inv. 

Map I-313. 

--- 1960b, Geologic map of Talkeetna Mountains (A-1) 

quadrangle and the south third of Talkeetna Mountains 

(B-1) quadrangle, Alaska: U.S. Geol. Survey Misc. Geol. 

Inv. Map I-314. 

Moffit, F. H., 1938, Geology of the Chitina Valley and adjacent area, Alaska: U.S. Geol. Survey Bull. 894, 137 p. 
D52 GEOLOGICAL SURVEY RESEAR-CH 19 6 2 

134. SOME LATE CRETA,CEOUS STRAND LINES IN SOUTHERN WYOMING 

By A. D. ZAPP and W. A. CoBBAN, Denver, Colo. 

Eastward withdrawal of the sea across most of 

southern Wyoming during the Campanian Stage was 

interrupted by several partial readvances of the sea, 

as recorded by superposition of tongues of marine 

strata on tongues of nonmarine strata. The larger 

regressive-transgressive cycles so recorded are described in this article, and the strand-line positions 

indicated by the seaward and landward limits of the 

tongues are shown on figure 134.1. 

This is a brief progress report on a field investigation begun in August 1961; the work thus far has 

not included subsurface studies. A similar report on 

a comparable investigation in the adjoining area to 

the south was published earlier by the authors (Zapp 

and Cobban, 1960). 

Gratitude is expressed to H. J. Hyden for the use 

of certain unpublished data in the area near the 

town of Rock River. 

For purposes of this. study, the rocks were classified 

broadly into marine and nonmarine facies, with two 

subfacies distinguished in each category. The general 

lithology and the geographic and stratigraphic distribution of these facies, and their relation to named 

stratigraphic units, are summarized on figure 134.2. 

The fossil zones are numbered to correspond to those 

used in the area to the south ( Zapp anJ Cobban, 1960, 

fig. 112.2) ; zone F9 of this report includes zones F9 

and FlO of the earlier report. 

The strata exhibit ·considerable variation in thickness of time-equivalent units. For example, the zones 

of B aculites perplewus and B aculites eliasi are separated by about 1,000 feet of strata in the northeastern 

part of the area; in the Rawlins area the stratigraphic 

separation is twice as great. V\T e attribute such variation in thickness to differential subsidence during 

sedimentation. 

Extreme depositional thinning and some local truncation of beds beneath Cretaceous unconformities 

obscure the normal transgressive-regressive relations 

in the area northwest of the town of Lamont (fig. 

134.2, sections 6-8). Time-equivalent strata that are 

normally separated by more than 4,000 feet of strata, 

as at locality 8 (figs. 134.1, 134.2) , are virtually in 

contact at locality 6 .. The strata comprising the Mesaverde Formation at locality 7 similarly wedge out 

almost completely in a ·westward direction-by depositional thinning and perhaps partly by truncation 

-about 41j2 miles we~t of locality 7. About 4 miles 

west of locality 7, in the south half of sec. 36, T. 27 N., 

R. 90 W., a pronounced unconformity is evident in 

the rocks lower in the stratigraphic section. Approxmately the upper two-thirds of a sequence of about 

1,000 feet of massive sandstone and siltstone pinches 

out eastward as a result of truncation before deposition of an overlying shale unit. The rocks above and 

below the unconformity are of marine origin, indicating submarine planation. The extreme local tectonic 

differentiation apparent in the Lamont area is, to the 

knowledge of the author~, unique in the predominantly 

marine facies of the Cretaceous rocks of western interior United States. Pronounced local thinning of 

the l\fesaverde Formation in this area was first pointed 

out by Fath and Moulton (1924, p. 27). 

The oldest regressive-transgressive cycle here enumerated is that reflected in the Rock Springs Formation and correlative strata (figs. 134.1 and 134.2, R1 

and T I). Actually it consists of more than one cycle, 

as the sea margin oscillated within a rather narrow 

belt during the accumulation of more than 1,000 feet 

of strata. An extraordinary thickness of massive 

marine sandstones was formed in the sea ward portion 

of this belt of oscillation, and a short distance seaward from the sea ward margin. 

Present evidence suggests that the Rock Springs 

regressive-transgressive cycle is represented along the 

Book Cliffs in east-central 1Jtah by the regressive 

Kenilworth coal zone of the Blackhawk Formation and 

the overlying marine-transgressive middle shale member of the Blackhawk Formation (Fisher, 1936, pl. 7, 

col. 1). This indicates that the strand line trended 

approximately S. 25° W. from the southern margin 

of figure 134.1 across the Uinta Basin in 1Jtah. Also, 

the Rock Springs regressive deposits are at least approximately equivalent to the most seaward nonmarine 

rocks of the Menefee Formation of the type Mesaverde 

Group in the San Juan Basin of southwestern Colorado 

and northwestern New Mexico. The nonmarine rocks 

of the Menefee Formation wedge out along a line that 

trends about N. 60° W. across the northeastern part 

of the San Juan Basin (Zapp, 1949). 

Following the upper Rock Springs transgression 

(TI), the sea retreated-perhaps with minor readvances-about 80 miles eastward (R2 ), then readvanced about 20 to 30 miles (T2 ). The regressive and 

transgressive phases of this cycle are direct correlatives of the Castlegate-Rim Rock regression and the 
41° 

110° 109° 

~)(I...J..R 1 I I I I 

Approximate seaward limit.of deposition of tongues of nonmarine 

rock 

Hachures point in landward direction. 

Obse1·ved outcrops at or near seaward 

limit indicated by x 

~ x.,-- T 1 --r-..,.--

Approximate landward limit of deposition of tongues of marine rock 

Hachures point in seaward direction. Ob-

.~erved outcrops at or near la-ndward 

limit indicated by X 

ARTICLE 134 

0 50 MILES 

EXPLANATION 

R 4 , Teapot regression 

"' T 3, pre-Teapot transgression 

~ R 3, Parkman regression 

T 2, Buck transgression 

'"' R2 , Castlegate and Rim Rock es regression 

~ T 1, upper Rock Springs transgression 

R 1, lower Rock Springs regression 

D53 

Laramie 

Outcrop area of Mesaverde 

Fonnation or Group 

Location of columnar sections 

FIOUUE 134.1.-Map of part of southern Wyoming, showing location of columnar sections (fig. 134.2), and general location and 

trend of certain regressive and transgressive strand lines during part of Late Cretaceous time, as inferred from outcrop 

studies. 

Buck transgression, respectively, of the area to the 

south (Zapp and Cobban, 1960), so the previous 

nomenclature is retained in this article. The strata 

of the transgl'essi ve phase in both areas have yielded 

species of Baculites referable to the zone of Baculites 

JJe'I']Jlew'us Cobban. 

The sea margin then retreated to a point approximately midway between points 12 and 13 on figure 

134.1. There, exposures in the northwestern part of 

Halleck R.idge show eastward laternl replacement by 

marine rocks of the lower 300 feet of the nonmarine 

part of the l\1esaverde Formation. , The sea margin 

oscillated within a belt a few miles wide during the 

deposition of these rocks. This feature is similar ~n 

stratigraphic position and relations to the lower lies 

regressive-.transgressive cycle in Colorado (Zapp and 
D54 

Q) 

~ ,.. 

"' 01 

(.) 

CD ALKALI 

BUTTE 

® 

EAST 

CONANT 

CREEK 

(Venne and Pipiringos, 1954) 

® 

GEOLOGICAL SURVEY RESEARCH 1 9 6 2 

® 

GLENROCK 

Lewis Shale 

Mesaverde Formation 

Cody Shale 

T- Teapot Sandstone Member (Mesaverde Formation) 

P- Parkman Sandstone Member (Mesaverde Formation) 

U- Unnamed middle member (Mesaverde-Formation) of Rich (1958) 

W- Wallace Creek Tongue (Cody Shale) of Barwin (1959) 

F- Phayles Member (Mesaverde Formation) of Barwin (1961) 

® 

FEET 

® EAST SHORE 

SEMINOE LAKE 

EXPLANATION Ia FOSSIL ZONES 

F22 Baculites grandis 

F21 Baculites baculus 

F20 Baculites eliasi 

F 19a Baculites jenseni 

Fl9 Baculites reesidei 

F I 8 Baculites cuneatus 

Fl 7 Baculites compressus 

F 16 Didymoceras cheyennense 

F I 5 Exiteloceras jenneyi 

F 14 Didymoceras stevensoni 

F 13 Didymoceras nebrascense 

F I 2 Baculites scotti 

F I I Baculites gregoryensis 

F9 Baculites perplexus 

FB Baculites sp. (smooth) 

F7 Baculites asperiform.is 

F6 Baculites maclearni 

F5 Baculites obtusus 

F4 Baculites sp. (weakly ribbed) 

F3 Baculites sp. (smooth) 

F2 Scaphites hippocrepis 

ROCKS OF 

NONMARINE 

ORIGIN 

ROCKS OF 

MARINE 

ORIGIN 

Undifferentiated lenticular 

deposits of sandstone, 

shale, and coal 

Persistent units of irregu· 

larly bedded sandstone 

rTTl 

LlilllJ 

Sandstone, massive to 

evenly bedded 

L..laJ 

~ 

Shale and siltstone, evenly 

bedded 

ROCK SPRINGS UPLIFT @ 

Almond 

Formation 

Ericson 

Sandstone 

"' 

~ Cl 

Q) 

~ Rock 

~ Sprin11s 

~ Formation 

Blair 

Formation 

(part) 

® 

ESPY AREA 

(Hale, 1961) 

B- Black Butte Tongue (Mancos Shale) of Hale (1955) 

C- Chimney Rock Tongue of Rock Springs Formation 

of Hale (1955) 

1000 

2000 

3000 

4000 

@ 

OVERLAND 

CROSSING 

Lewis Shale 

Cody Shale 

CT- Upper tongue of Cody Shale of Weimer and Guyton 

(1961) 

CS- Sandstone member of Cody Shale of Weimer and 

Guyton (1961) 

PR- Pine Ridge Sandstone Member (Mesaverde Forma· 

tion) 

@ 

ALLEN 

STATION 

~ 

FOOTE 

CREEK 

@ 

ROCK 

RIVER 

H- Hatfield Sandstone Member (Mesaverde Formation) of Hale (1961) 

E- Espy Tonaue (Steele Shale) of Hale (1961) 

D- Deep Creek Sandstone Member (Mesav.erde Formation) of Hale (1961) 

PR- Pine Ridge Sandstone Member (Mesaverde Formation) 

-~ 

1 

~ ~ 

ll 

:I 

FIGURE 134.2.-Generalized columnar sections of the Mesaverde Formation and adjacent rocks in part of southern Wyoming, 

showing distribution of facies and correlation of named stratigraphic units. For location of sections and explanation of 

T's and R's, see figure 134.1. Sections are modified after the authors cited. 
•· 

ARTICLE 134 D55 

Cobban, 1960) . The strand line at this time is not 

. shown on figure 134.1. 

This was followed by retreat of the strand line to 

the position of the Parkman regression (Ra) as shown 

on figure 134.1. The Parkman regression is comparable in stratigraphic position to the middle IlesPalisade regression of the area to· the south (Zapp 

and Cobban, 1960) but may be slightly older. 

rrhe sea margin then readvanced, with several subordinate oscillations, to the position shown as the preTeapot transgression (T3 ) on figure 134.1. This is 

the approximate or exact equivalent of the upper 

Iles-lower l\{ount Garfield transgression of the area 

to the south (Zn.pp and Cobban, 1960). A marine 

tongue exposed about 14 miles northeast of Baggs 

(fig. 134.1) is ·now believed to be a product of this 

trans.gression; previously (Zapp and Cobban, 1960, 

Joe. Y), it was thought to represent a later transgressiOn. 

The sea margin then retreated to a position near 

the east edge of the area, and this is termed the Teapot 

regression (R.4 ). It is correlated with the lower 

'Villiams Fork-lower Bowie regression of Colorado 

(Zn,pp n,nd Cobban, 1960). The Teapot regression 

is ma,rked in the l\fedicine Bow area by the Pine Ridge 

Sandstone l\{ember and associated coaly rocks. The 

Pine Ridge Sandstone Member is extensively exposed 

in the ftrea between Rawlins and Lamont, and in that 

area it resembles the Ericson Sandstone of the Rock 

Springs area. The Pine Ridge Sandstone may represent a tongue of the upper part of the Ericson Sandstone. 

The Tea,pot regression was followed by extensive 

readvance of the sea and by deposition of the thick 

marine Lewis Shale. In the southern part of the area 

this ad vance of the sea margin exceeded 150 miles, to 

the vicinity of Rock Springs. In the northern part 

of the area, the transgression was less than half as 

extensive, and was interrupted by a major regressive 

movement (Rich, 1958, p. 2442). · 

The marine Lewis Shale, at least east of the longitude of Baggs, includes the time equivalent of the 

upper 'Villiams Fork regressive tongue of Colorado 

(Zapp and Cobban, 1960). That tongue has not been 

recognized in "Vyoming. . .. 

REFERENCES 

Barwin, J. H., 1959, Facies of the Mesaverde Formation: Am. 

Assoc. Petroleum Geologists, Rocky Mtn. Sec., 1959 Geological Record: p. 139-142. 

---- 1961, Stratigraphy of the Mesaverde Formation in the 

southem part of the Wind River Basin, Wyoming, in 

Wyoming Geol. Assoc. Guiclebook 16th Ann. Field Conf., 

Green Hiver, 'Vashakie, 'Vind Hiver, and Powder River 

Basins, 1961: p. 173. 

F'ath,, A. E., and Moulton, G. F., 1924, Oil and gas fields of 

the Lost Soldier-Ferris district, Wyoming: U.S. Geol. 

Survey Bull. 756, p. 27. 

F'isher, D . .1., l936, The .Book Cliffs coal field in Emery and 

Grand Counties, Utah : U.S. Geol. Survey Bull. 852, p. 13, 

pl. 7. 

Hale, L. A., 1V55, Stratigraphy and facies relationships of the 

Montanan Group in south-central Wyoming, northeastern 

Utah, and northwestern Colorado, in ·wyoming Geol. Assoc. 

Guidebook lOth Ann. Field Conf., Green Hiver Basin, 1955: 

p. 90-92. 

--- 1961, Late Cretaceous (Montanan) stratigraphy, eastern Washakie Basin, Carbon County, Wyoming, in Wyoming Geol. Assoc. Guidebook 16th Ann. Field Conf., Green 

Hiver, 'Vashnkie, Wind River, and Powder River Basins, 

1961 : p. 130, 131, 133. 

Rich, E. 1., 1958, Stratigraphic relation of latest Cretaceous 

rocks in p~uts of Powder Rivet·, 'Vind River, and Big 

Hom Basins, 'Vyoming: Am. Assoc. Petroleum Geologists Bull., v. 42, no. 10, p. 2442. 

Sears, .J. D., 1926, Geology of the Baxter Basin gas field, 

Sweetwater County, Wyoming: U.S. Geol. Survey Bull. 

781-B, pl. V. 

Smith, .T. H., 1961, A summary of stratigraphy and paleontology, Upper Colorado and Montanan Groups, south-central 

V\'yoming, northeastet·n Utah, and northwestern Colorado, 

In Wyoming Geol. Assoc. Guidebook 16th Ann. Field Conf., 

Green River, Washakie, Wind Hiver, and Powder River 

Basins, 1961 : pl. I. 

Weimer, R. J., and Guyton, J. W., 1961, Geology of the-.Muddy 

Gap-Lamont area, Wyoming, 'in Wyoming Geol. Assoc. 

Guidebook 16th Ann. Field Conf., Green Hiver, Washakie, 

Wind Hiver~ and Powder River Basins, 1961: p. 143. 

Yenne, K. A., and Pipiringos, G. N., 1954, Stt·atig~·nphic sections of Cody shale and younger Cretaceous and Paleocene rocks in the 'Vinci River Basin: U.S. Geol. Survey 

Oil and Gas Inv. Chart OC-49. 

Zapp, A. D., 1949, Geology and coal resources of the Durango 

area, La Plata and Montezuma Counties, Colorado: U.S. 

~eol. Survey Oil and Gas Inv. Prelim. Map 109. 

Zapp, A. D., and Cobban, W. A., 1960, Some Late Cretaceous 

strand lines in northwestern Colorado and northeastern 

Utah: Art. 112 in U.S. Geol. Survey Prof. Paper 40Q-B, 

p. B246-B249. 
D56 GEOLOGICAL SURVEY RESEARCH 1 9 6 2 

135. TERTIARY VOLCANIC AND RELATED ROCKS OF THE REPUBLIC AREA, FERRY COUNTY, WASHINGTON 

By SIEGFRIED MuESSIG, Los Angeles, Calif. 

A thick sequence of Tertiary volcanic rocks and 

related sedimentary and intrusive rocks were found 

during recent mapping (Muessig and Quinlan, 1959) 

to underlie large parts of the Republic and the eastern 

half of the Aeneas quadrangles (fig. 135.1). These 

rocks include flows, tuffs, breccias, intrusive bodies, and 

lake beds; their composition ranges from rhyodacite 

to basalt. With the exception of the intrusives, these 

rocks are confined to the large Iiortheast-trending Republic graben (fig. 135.1) that occupies the greater 

part of the Republic quadrangle and part of the 

Aeneas quadrangle. 

This sequence is here divided into four new formations. From oldest to youngest these are the O'Brien 

Creek Formation, Sanpoil Volcanics, Scatter Creek 

I 

_j 

Rhyodacite, and RJondike Mountain Formation. All 

. have been traced northward into the adjacent Curlew 

quadrangle, and all except the Klondike Mountain 

have been traced southward into adjacent quadrangles. 

O'BRIEN CREEK FORMATION 

The basal Tertiary formation in the Republic area 

.is the O'Brien Creek Formation, which consists largely 

of water-laid tuff and some conglomerate; it is here 

named for typical exposures along the North· Fork 

of O'Brien Creek, the type section (fig. 135.1). The 

O'Brien Creek Formation underlies most of the Republic graben but crops out principally along tlie 

sides of the graben, although some outcrops are near 

its center in the northern part of the Republic quadCURLEW QUADRANGLE 

'

TOM THUMB 

MINE . 

I .T p N 1 

~ ____ .) 

1 0 I I I,, 

REPUBLIC 

QUADRANGLE 

~ 2 3 4 5 6 MILES 

I I I I I 

FIGURE 135.1.-lndex map of the Republic area showing type localities of the four new formations: (1) O'Brien 

Creek Formation, (2) Sanpoil Volcanics, (3) Scatter Creek Rhyodacite, and (4) Klondike Mountain Formation. 

~ 

I 
ARTICLE 135 D57 

rnngle. I-Iere the O'Brien Creek unconformably overlies metamorphosed sedimentary rocks of Paleozoic 

age. 

A complete section of the O'Brien Creek Formation 

is nowhere exposed; hence, the total thickness of this 

formation cannot be determined accurately. Both 

the lithology and thickness of the formation differ 

fr01n place to place. Along the east side of the 

graben north of the North Fork of the Sanpoil River 

the formation is at least 4,200 feet thick, and 7 miles 

south of here at the south edge of the Republic 

graben it is 2,300 feet thick. On the west side of the 

graben along Scatter Creek, 1,350 feet of the formation 

is exposed . 

. The greater part of the O'Brien Creek Formation 

consists of a white to greenish-white water-laid crystal 

tuff. Crystal fragments, 1 to 4 mm in diameter, make 

up as 1nuch as 70 percent of this rock. Plagioclase, 

quartz, and orthoclase crystals are the major constituents, but biotite, sericite, sphene, apatite, calcite, 

magnetite, and pyrite are present in minor amounts. 

This crystal tuff commonly contains a few rock fragments that range from a fraction of an inch to several 

inches in diameter. Locally the fragments constitute 

as much as 30 percent of the rock. These fragments 

are characteristically chips of phyllite or argillite, 

with minor more equidimensional clasts of greenstone, 

quartzite, and granitic rocks. The matrix is ash. 

Two other ty1)es of rock occur locally in this formation. One is dark fine-grained water-laid 'tuff that 

resembles shale. In some places this tuff contains 

carbonized plant debris and in one place to the east 

of Curlew Lake it contains several thin beds of iignite. 

The other rock type is boulder conglomerate, beds of 

which have been found both in the upper and lower 

parts of the formation. In some places the boulders 

are mainly argillite, phyllite, and schist, and in other 

places they are mainly quartz monzonite and granodiorite. 

Plant fossils from the dark tuff east of Curlew Lake 

were reported by R. W. Brown to be Eocene ( ~) in 

age. The O'Brien Creek Formation is thus assigned 

an Eocene ( ~) age. The formation is roughly correlative with the l(ettle River Formation of Daly ( 1912), 

which is found to the north in British Columbia; it is 

the dacite flow conglomerate of Umpleby (1910) and 

the breccia-conglomerate of Lindgren and Bancroft 

(1914). 

SANPOIL VOLCANICS 

The Sanpoil Volcanics is a thick sequence of rhyodacite and quA.rtz latite flows and minor tuff and flow 

breccia that conformably overlies the O'Brien Creek 

Formation and unconformably underlies the l{]ondike Mountain Formation. This formation is here 

named after the Sanpoil River valley, whose walls are 

carved in this unit for many miles south of Republic. 

The type locality is 7 miles south of Republic. The 

Sanpoil has the most extensive exposures of any rock 

unit in the graben, and south of Republic the· outcrops 

are nearly ·continuous from one side of the graben 

to the other. The base of the Sanpoil is placed at the 

base of the first flows that overlie the water-laid tuffs 

of the O'Brien Creek Formation. 

The Sanpoil Volcanics, like the O'Brien Creek Formation, varies i.n thickness from place to place. The 

formation is approximately 4,000 feet thick on the 

east side of Klondike Mountain. 

.The greater part of the Sanpoil Volcanics is made 

up of light-gray to black, brown-weathering rhyodacite 

or quartz latite flows. These flows commonly form 

prominent outcrops that in places show prominent 

flow banding. The rhyodacite or quartz latite is a 

porphyritic rock with the phenocrysts generally making up less than 50 percent of the rock. The mafic 

minerals, hornblende and biotite, make up about 60 

percent of the phenocrysts. Plagioclase ( An35- 65 ) 

constitutes most of the remaining 40 percent. Augite 

and hypersthene n.re present in some flows. Accessory' 

minerals include apatite, magnetite, sphene, leucoxene, 

zircon, and calcite. The groundmass consists of partly 

devitrified brown glass. 

Locally, fine-grained light-yellowish-brown tuffs are 

found interbedded with the flows. Rock fragments 

in the tuffs are few and are generally glass. 

Flow breccias crop out along the Sanpoil River in 

the southern part of the area. They consist of numerous brown angular pieces of rhyodacite as much as 

8 inches across in a matrix of similar material. 

Fossils were· not found in the Sanpoil Volcanics, 

but it is herein ass'igned an Eocene ( ~) age; it underlies the I\Jondike Mountain Formation, which contains Oligocene fossils, and overlies the o~Brien Creek, 

which contains probable Eocene fossils. 

SCATTER CREEK RHYODACITE 

The name Scatter Creek Rhyodacite is here given 

to the widespread porphyritic intrusive rocks that are 

younger than the O'Brien Creek Formation but older 

than the Klondike Mountain Formation. The name 

comes from Scatter Creek in the southeastern partJ of 

the 'Vauconda quadrangle, where excellent exposures 

of thi~ rock occur at the type locality along the road 

leading up this creek (fig. 1). The greater part of 

. the Scatter Creek is found in the graben along its 

east and west margins, although some Scatter Creek 

intrusives occur outside the graben. The Scatter Creek 

cuts metamorphosed sedimentary rocks of Permian 
·D58 GEOLOGICAL SURVEY RESEARCH 19 6 2 

age, quartz monzonite of Cretaceous age, the O'Brien 

Creek Formation, and in a few places the Sanpoil 

Volcanics. It .fonns dikes, sills, or irregular intrusive 

bodies. The Scatter Creek in part closely resembles 

some of the flows of the Sanpoil Volcanics. Although 

in a few places the intrusive relations between these 

two rocks are clear cut, in other places the t'vo appear 

to grade into one another. 

The Scatter Creek Rhyodacite is a light-gray to 

dark-greenish-gray, brown-weathering porphyritic 

rock. Phenocrysts have an average length of about 

1 mm and consist principally of plagioclase (Anao-Mi), 

and of hornblende and biotite, which are in a few 

places altered to chlorite, sphene, calcite, and epidote. 

Augite, sanidine, and quartz are also present in some 

places. Accessory minerals include· magnetite, apatite, and zircon. The groundmass is generally partly 

devitrified glass. Although the greater part of the 

Scatter Creek is rhyodacite, quartz latite i~ common 

and several other rock types also occur. 

This formation is probably of about the same age 

as the Sanpoil Volcanics, although part of it at least 

is younger than the older part of the Sanpoil. It is 

herein assigned an Eocene or Oligocene age. 

KLONDIKE MOUNTAIN FORMATION 

The name Klondike lVIountain Formation is here 

given to the volcanic rocks that unconformably overlie 

the Sanpoil Volcanics and the Scatter Creek Rhyodacite; the volcanic rocks are the youngest in the 

Republic area .. The name comes fron1 I\Jondike 

Mountain, north of Republic, whose top and western 

slope, herein designated the type locality, are underlain by pyroclastic rocks and flows of this formation. 

The Klondike Mountain is divided into three members: ( 1) a lower member of mostly fine-grained 

water-laid tuff, (2) a middle member of coarse pyroclastic rocks, and (3) an upper member of basalt 

flows. The lower member is well known for excellent 

plant fossils that have been: found iri it, and because 

of this importance is here named the Tom Thumb 

Tuff ~iember after the Tom Thumb mine, 3lj2 miles 

north of Republic (fig. 135.1). 

The I\]ondike ~iountain Formation crops out in 

a fairly narrow band along the west side of the graben 

from about 3 miles south of Rep11blic northward into 

the adjoining Curlew quadrangle. The outcrop area 

of the Tom Thumb Tuff ~iember is much more limited 

in extent and is not found more than 5 miles north 

of Republic. An angular unconformity separates the 

formation from the underlying Sanpoil Volcanics. 

The base of the formation is placed at the base of a 

thin volcanic breccia at the bottom of the Tom Thumb, 

or where this member is not present, at the base of 

the thick volcanic breccia that elsewhere is the middle 

member of the formation. An angular unconformity 

also separates the Tom Thumb from the middle member; the upper two members are apparently conformable. 

The thickness of the members varies from place to 

place. The Tom Thumb has a maxi1num thickness 

of about 1,000 feet 2 miles northwest of Republic; it 

thins abruptly, and is absent a little n1ore than a 1nile 

to the east of this point. The middle member is about 

800 feet thick, and the upper member is 200 feet thick 

on l(londike ~fountain. In the adjoining Curlew 

quadrangle both members are n1uch thicker. 

The Tom Thumb ~fember consists of two units. 

The ba.sal unit is volcanic breccia, conglomerate, and 

tuff. This unit has both rounded and anguhtr volcanic fragments as much as several feet across in a 

fine- to coarse-grained tuffaceous matrix. Overlying 

this and making up the greater part of the member is 

a fine-grained well-sorted water-laid light-tan to 

orange tuff that contains abundant. plallt debris. 

The middle member consists of buff coarse volcanic 

breceia.s made up of angular fragments of porphyritic 

latite, as much as several feet in diameter, in a tuffaceous matrix. This member also contains a few olivegray to buff basalt flows. 

The upper member is a brownish-black porphyritic 

basalt. The phenocrysts are principally labradorite 

with some phenocrysts of augite, hypersthene, and 

olivine. These are set in n. gronndmnss containing 

abundant microlites of andesine, augite, and magnetite. · 

Numerous fossil plants have been ·found in the Tom 

Thumb ~!ember. These have been elated as Oligocene 

by H.. "\V. Brown (1059, p. 127). The formation is 

accordingly assigned an Oligocene age. liowever, the 

middle and upper members of the J(londike ~fountain 

ma,y be younger than Oligocene. 

REFERENCES 

Brown, H. W., 1959, A bat ancl some plants from the upper 

Oligocene of Oregon: Jour. Paleontology, v. 33, p. 125-129. 

Daly, R A., 1912, Geology of the North American Cordilleran 

at the forty-ninth parallel: Canada Geol. Survey Mem. 

38, p. 2, 857 p. 

Lindgren, 'Valdemar, and Bancroft, Howland, 1914, The Hepublic mining district, 'in Bancroft, Howland, The ore deposits of northeastern 'Vashington: U.S. Geol. Sm·vey 

Bull. 550, p. 133-166. 

Muessig, S .. J., and Quinlan, J .. T., 1959, Geologic map of the 

Hepublic and part of the 'Vauconda quadrangles, Washington: U.S. Geol. Survey open-file report. 

Umpleby, .J. B., 1910, Geology and ore deposits of the Hepublic mining district: Washington Geol. Sm·ve.v Bull. 1, 

65 p. 
ARTICLE 136 D59 

136. GEOLOGY OF TERTIARY ROCKS JN ESCAMBIA AND SANTA ROSA COUNTIES, WESTERN FLORIDA 

By OwEN T. MARSH, Waynesville, N.C. 

·wo·rlc. !lone ·in cooperation 'loith the Jr'lori!lu Geological Survey, Esoa.mb1a. Co·nnty, Santa Rosa County, and the city of Pensacola 

This summary of the geology of Escambia and 

Santa Rosa Counties, Fla. (fig. 136.1), is based primarily on sam pies from and electric logs of 60 oil 

test holes and 13 deep water wells. The fossils were 

identified by S. M. I-Ierrick, Ruth Todd, Druid Wilson, a.nd Estella Leopold, of the U.S. Geological Survey; G. A. Cooper, of the U.S. Na1tional :Museum; and 

I-I. S. Puri, of the Florida Geological Survey, The 

stratigraphic units are described below in ascending 

order. 

STRATIGRAPHY 

The I-Iatchetigbee Formation, the youngest formation. of the Wilcox Group (lower Eocene) in westernmost Florida, consists chiefly of gray silty micaceous 

clay and averages 315 feet in thickness (fig. 136.2). 

It also contains some· glauconitic shale, siltsone, and 

shaly limestone. Fossils include foraminifers, corals, 

echinoids, and abundant mollusks. 

The Tallahatta Formation (Claiborne Group, midALABAMA 

------·--== -i 

·'· I 

·~ANTA ROSA ./ I / I 

--· I 

·~·~./·i / I 

BALDWIN Milton/"· I~ 

COUNTY 

0 10 MILES 

IrwuHI!: 136.1.-Mnp of l)Jscambia and Santa Rosa Counties, 

Fin., showing location of fence <;}ingram in figure 13R2. Dots 

::;how location of wel1s. 

654685 0-62-5 

dle Eocene) is of variable lithology, consisting mostly 

of hard light-gray calcareous shale and siltstone with 

numerous beds of gray limestone and poorly sorted 

sand. It averages 255 feet in thickness. Foraminifers 

and a few gastropods are present. 

In the Florida panhandle (Puri and Vernon, 1959, 

p. 42) and southern Escambia County, Ala. (Winter, 

1954, p. 127), a thick section, predominantly of limestone, has been correlated with the Lisbon Formation 

of middle Eocene age. In the western part of the panhandle this sequence is chiefly a grayish shaly glauconitic limestone with some shale and averages about 

500 feet in thickness. This section is so different from 

the Lisbon at its type locality in Alabama that, pending further study, it is referred to here as the Lisbon 

Formation equivalent. The basal part of the Lisbon 

equivalent is locally rich in glauconite and phosphate. 

About' 40 species of foraminifers, as well as a few 

ostracodes, echinoids, worm tubes, and other fossils of 

middle Eocene age were identified from the formation. 

The Ocala Limestone (Jackson Group, upper 

. Eocene) underlies the western panhandle at depths 

ranging from 290 t9 1,940 feet below sea level. The 

Ocala averages 165 feet in thickness within the area 

and thickens eastward across the panhandle. The formation is a light-gray to chalky-white limestone composed mainly of foraminifers, mollusks, corals, echinoids, and other fossils. l\{ore than 60 species of foraminifers were identified. 

Unconformably overlying the Ocala Limestone is the 

Bucatunna Clay Member of the Byram Formation 

(Vicksburg Group, middle Oligocene). The Bucatunna averages 125 feet in thickness in Escambia and 

Santa Rosa Counties but thins eastward and pinches 

out about 32 miles east of the area (Marsh, 1962, 

p. 246). The Bucatunna is a dark-gray soft silty to 

sandy clay. Although it contains few fossils, 26 

species of foraminifers were identified. 

The Chickasawhay Limestone (upper Oligocene) 

and Tampa Limestone (lower Miocene) cannot be 

distinguished lithologically in the western panhandle 

except in a few places and are therefore shown in 

figure 136.2 as undifferentiated. The Chickasawhay 

-consists of gray vesicular limestone and dolomitic 

limestone with some light-brown dolomite. Fragments of these rocks have a characteristic knobby 

texture. The Tampa Limestone is hard, light gray to 
D60 GEOLOGICAL SURVEY RESEARCH 1962 

. FEET 

0 

1000 

20000'-------:5~----:' 

MILES 

EXPLANATION 

CJI] 

Citronelle Formation 

D 

Coarse clastic deposits 

~ Clay 

Upper clay member; sand 

member; lower clay member 

~ Tampa 

-

and Chicka-

~ sawhay Limestones 

g > 

5 OIIJ ~ . Bucatunna Clay Member c:: 

of Byram .Formation ~ 

Ocala ~ Limestone 

D 

Lisbon Formation 

equivalent 

Tallahatta ~ Formation 

D 

Hatchetigbee Formation 

Contact 

Dashed where approximately located 

lfr 

Fault 

Showing relative movement 

FIGURE 136.2.-Fence diagram of geologic formations in Escambia and Santa Rosa Counties, Fla., and Baldwin County, Ala. 

Datum is mean sea level. Contacts are generalized and beds above sea level are omitted. Short vertical lines are water wells; 

long vertical lines are oil test holes. 

grayish white, and is generally not dolomitic. It is 

less vesicular and contains more clay than the Chickasawhay. The Chickasawhay Limestone underlies the 

entire area and thickens from about 30 to 130 feet 

toward the Gulf of Mexico. The Tmnpa, however, is 

present' only in the southern half of the area, where 

it has a maximum thickness of 270 feet. Both formations contain diagnostic foraminifers; in addition, 10 

species of mollusks were identified from the Tampa. 

A new· stratigraphic unit of middle Miocene age 

overlies the Tampa and Chickasawhay Limestones. 

The unit comprises a lower member and an upper 

member, each composed of tough gray sandy clay, 

separated by a thin bed of sand (fig. 136.2). In 

Escambia and Santa Rosa Counties the Miocene clay 

unit ranges from about 380 to 980 feet in thickness. A 

few miles north of Pensacola the clay interfingers 

with unnamed coarse clastic deposits of the same age, 

discussed in the next paragraph. The lower member 

terminates 28 miles east of the area, where it is unconformably overlain by the Citronelle Formation; 

the upper member terminates in southeastern Santa 

Rosa County by interfingering with the unnamed 

coarse clastic deposits. Thus, the Miocene clay is 

wholly confined to the subsurface. The clay is micaceous and contains carbonized plant remains. In 

places, thick beds of mollusk shells occur near the 

top of the upper member. Sixty-four species of foraminifers were identified from the formation. 

A thick sequence of brown to gray very fine to very 

coarse pebbly sand and gravel rests upon the Miocene 

clay in the southern part of the area and upon the 

Chickasawhay Limestone in the northern part. Pending further study, these beds are referred ·to by the 
'• 

1 

r 

ARTICLE 136 D61 

Florida Geological Survey as "unnamed coarse clastics." The unit contains lenses of carbonaceous clay 

and siltstone as much as 180 feet thick. Beds of 

minute mollusk shells are found throughout the cmuse 

clastic deposits and serve to distinguish these beds 

from the Citronelle Formation. Diagnostic mollusks 

and foraminifers date the coarse clastics as chiefly 

middle l\iiocene, although at four localities late l\iiocene fossils were found. 

The Citrmielle Formation of Pliocene age is lithologically similar to the unnamed coarse clastics except 

for the virtual absence of shells in the Citronelle. 

The exact thickness of the Citronelle in westernmost 

Florida is uncertain because it is capped by litho- . 

logically similar marine terrace deposits of Pleistocene age. :However, the formation probably ranges 

from about 40 to about 800 f.eet jn thickness. Layers 

of sand cemented by iron oxides are common in the 

Citronelle, and in the upper part, thin zones of charcoal are found. Samples of logs penetrated by wells 

at depths of 50 to 200 feet have a fresh appearance 

that suggests they .are thousands rather than millions 

of years old. Quaternary pollen, identified by Estella Leopold in samples of the Citronelle collected by 

the writer, suggests a possible Pleistocene age for the 

formation. Other fossils ii1clude mollusk shells in 

well samples from depths of 20 to 300 feet, and locally 

abundant kaolinite tubes that were probably the 

burrows of aquatic animals. 

STRUCTURE 

A northwestward-trending graben (fig. 136.2) enters 

~he area from Alabama on the north. In Florida it is 

bounded on the west by the Jay fault (not previously 

recognized) and on the east by the Foshee fault. The 

Pollard and S~uth Pollard faults within the graben 

have lesser offsets. At the Pollard oil field, 2 miles 

north of the area, oil is produced from structural 

traps along some of these faults (Winter, 1954, p. 

126). Recurrent movement on all these faults, contemporaneous with deposition of the beds, took place 

over many millions of years. This caused the beds 

on the downthrown side of each fai:tlt to be thicker 

than the corresponding beds on the u pthrown side, 

thus the throw increases with depth. The ultimate 

cause of the graben faulting may have be.en withdrawal of support by lateral flowage of salt at great 

depths beneath the area. The Mississippi salt dome 

basin, a southeastward-trending concentration of salt 

dome, lies only 32 miles to the northwest and trends 

directly toward the western Florida panhandle. 

REFERENCES 

Marsh, 0. T., 1962, Relation of Bucatunna Clay Member (Byram Formation, Oligocene) to geology and ground water 

of westernmost Florida : Geol. Soc. America Bull., v. 73, 

p. 243-252. 

Puri, H. S., and Vernon, R. 0., 1959, Summary of the geology 

of Florida and a guidebook to the classic exposures : Florida Geol. Survey Spec. Pub. 5, 255 p. . 

Winter, C. V., Jr., 1954, Pollard field, Escambia County, Ala.: 

Gulf Coast Assoc. Geol. Soc. Trans., v. 4, p. 121-142. 
D62 GEOLOGICAL SURVEY RESEAR·CH 1 9 6 2 

13·7. STRATIGRAPHY AND HYDROLOGY OF THE JUANA DIAZ FORMATION IN THE YAUCO AREA, PUERTO RICO 

By I. G. GnossMAN, San Juan, Puerto Rico 

lVork dmw ·in cooperation with the Oomrnonwea.lth of Puerto R.'ico 

Reconnaissance geologic mapping for a water-resources investigation in southwestern Puerto Rico included an area of about 50 square miles extending 

east from Yauco to Guayanilla and south to the 

Caribbean Sea. The northwestern part, covering 

about 15 square miles near Yauco (fig. 137.1), produced new stratigraphic information of hydrologic 

significance. 

The northern part of the mapped area is underlain 

by a complex of Cretaceous igneous, sedimentary, and 

metamorphic rocks. South of the complex, clastic 

sedimentary rocks of the Juana Diaz Formation of 

middle Oligocene· age are exposed in an east-trending 

belt. Still farther south is an east-trending belt of 

the Ponce Limestone of Oligocene and Miocene age 

(Zapp and others, 1948). 

The name Juana Diaz was first used as a local term 

by Berkey ( 1915), who estimated the beds to be about 

3,000 feet thick. Mitchell (1922), who made the first 

geologic map of southwestern Puerto Rico, used the 

name for a formation estimated to be only 750 feet 

thick. Zapp and others (1948) subdivided the formation into three members: an upper shale member about 

460 feet thick, a middle member of sandy limestone 

and limy shale about 1,230 feet thick, and a lower 

member of sandy conglomerate about 460 feet thick. 

They suggested that the main basin of deposition was 

in the eastern part of the belt of exposure near Santa 

Isabel, about 30 miles east of Yauco, because the oldest clastic rocks were believed to be confined to that 

area. Slodowski ( 1956, p. 107) recognized two comparatively large areas of clastic rocks at Yauco separated by a thin belt of Quaternary surficial deposits, 

which he mapped as the Juana Diaz and Ponce Formations, undifferentiated. 

The present study indicates that a sizeable basin 

filled with clastic rocks of the Juana Diaz extends 

from south of Palomas northward about 2.8 miles. 

The basin may also extend southward from Palomas, 

but it is covered by the overlying Ponce Limestone. 

Faulted Juana Diaz crops out as far as 2.5 miles 

southeast of Palomas (not shown on map). Northwest of Palomas the Juana Diaz ends abruptly just 

outside the west boundary of the area of figure 137.1, 

where the formation is in contact with the Cretaceous 

rocks. To the east the bedrock is covered by alluvial 

sediments of the Rio Y au co, but beds of the Juana 

Diaz crop out on the east side of the river, in a belt 

about a mile wide, i1ear the east boundary of the area. 

Northwest of Yauco a striking basal conglomerate 

of the Juana Diaz is made up of abundant ellipsoidal 

rsTI 

L:2d 

Alluvium and 

colluvium 

Ponce Limestone 

Juana Diaz Formation 

EXPLANATION 

}i 0 

>-

0::: 

<( 

f= 

0::: 

w 

1-

~ )§ Igneous, metamorphic, ~ and sedimentary rocks ~ 

--<,5 

Strike and dip 

of beds 

"'22 

Approximate direction and 

amount of dip of beds 

u 

FIGURE 137.1.-Geologic map of the Yauco area. 

•l 

I 

I~ 
-. 

ARTICLE 137 D63 

boulders and large cobbles of hard Cretaceous rocks. 

This is overlain west of Yauco by eobble and pebble 

conglomerate, which in turn is overlain southwest of 

Yauco by sandstone and pebble eonglomerate. In 

general the coarsest materials are to the north and the 

finest to the south, although there is considerable interbedding. Slodowski ( 1956) assigned this sequence 

to the lower and middle members of the Juana Diaz 

Formation. The present study indicates that lithologically most of it belongs to the lower member. 

The Juana Diaz Formation strikes generally eastwest and dips gently about 10°-28° S. The regional 

dip of the Cretaceous rocks is also south, but the dips 

are commonly steeper. The beds in the northeastern 

part of the basin dip southwestward, and those in the 

northwestern part dip southeastward. Although the 

observations are few, they indicate that the long axis 

of the basin is approximately north-south. 

The Juana Diaz was computed to be at ]east 4,000 

feet thick along a line extending northward from near 

Palomas, by conservatively assuming an average dip 

of 15°. Possibly this great thickness is only apparent, resulting from unrecognized duplication of the 

section or reversal of dip, owing to faulting or folding. Indeed, the present investigation has disclosed 

faulting of the Juana Diaz and adjaeent units with 

appreciable disphtcement in the central San Francisco 

area, about 2.5 miles southeast of Palomas (not shown 

on map). However, the relatively uniform dip and 

gradation in grain size suggest that the beds near 

Yauco are relatively undisturbed. 

If detailed investigation confirms the estimated 

thickness of the conglomerate at Y au co and its assignment to the lower member of the Juana Diaz 

Formation, the composite maximum thickness, when 

the middle and upper members are added, may be 

5,500 feet. The three members do not attain their 

maximum thickness at any one place however. In 

fn.ct, the lower member may be a fresh-water or 

brackish-water deposit, as suggested by the embayed 

shape and orientation of the axis of the basin near 

Y auco, which is perpendicular to the east-trending 

Cretaceous source area to the north. The formation 

does not thicken eastward along the south coastal 

plain of Puerto Rico as formerly believed (Zapp and 

others, 1948). Rather, the maximum thickness is 

probably near Yauco, where the occurrence of coarser 

clastic rocks requires revision of the older notion that 

these are confined to the eastern type area near Juana 

Diaz. 

The intergranular spaces of the conglomerate are 

filled with sand and finer materjal, and the poor sorting results in low porosity ~ind permeability. A well 

drilled for water .in a lowland about halfway between 

Palomas and Yauco penetrated about 75 feet of clastic 

rocks of the Juana Diaz but yields only about 5 gallons per minute. The water is so highly mineralized 

that it is unsuitable for human consumption and is 

used for-stock only. The poor chemical quality suggests slow circulation of ground water. The few 

wells tapping the Juana Diaz Formation elsewhere 

in Puerto Rico are generally on hillsides, hence it has 

been difficult to determine whether their low yields 

result from the impermeable character of the formation or from their unfavorable topographic location. 

If this example is typical, lithology is a more important influence on yield than topography. By contrast, 

a well tapping alluvium just south of Yauco yields 

several hundred gallons per minute of potable water 

which is used for irrigation. The higher yield and 

lower mineralization are due to better sorting of the 

alluvial sand and gravel, looser packing, and lack of. 

cementing material. The resulting higher permeability affords better opportunity for recharge frmn 

surface water in Quebrada Berrenchin. The Juana 

Diaz Formation is thus a .relatively unproductive 

aquifer even at Yauco, where it seems to attain its 

maximum known thickness. 

REFERENCES 

Berkey, C. P., 1915, Geological reconnaissance of Porto Rico: 

New Yot·k Acad. Sci. Annals, v. 26, p. 13. 

Mitchell, G. J., 1922, The geology of the Ponce District, Porto 

Rico: New York Acad. Sci., Sci. Survey of Porto Rico 

and the Virgin Islands, v. 1, pt. 3, p. 229-300. 

Slodowski, T. R., 1956, Geology of the Yauco area, Puerto 

Rico: Princeton Univ. and Industrial Lab., Puerto Rico 

Admin. de Fomento, 130 p. 

Zapp, A. D., Bet·gquist, H. R., and Thomas, C. R., 1948, Tertiary geology of the coastal plains of Puerto Rico: U.S. 

Geol. Survey Oil and Gas Inv. Prelim. Map 85, sheet 2. 
D64 GEOLOGICAL SURVEY RESEARCH 19 6 2 

138. PYROCLASTIC DEPOSITS OF RECENT AGE AT MOUNT RAINIER, WASHINGTON 

By DwiGHT R. CRANDELL, DoNAL R. MuLLINEAux, RoBERT D. MILLER; and MEYER RuniN: 

Denver, Colo.; Washington, D.C. 

A study of surficial deposits in Mount Rainier N ational Park has led to the recognition of six distinctive layers of relatively light-colored pyroclastic 

debris on the flanks of Mount Rainier volcano, and on 

neighboring slopes of the Cascade Range. On slopes 

and ridgetops the layers locally are included in deposits totaling less than 6 feet in thickness. In terrace deposits in the valleys, however, the layers may 

be separated by tens of feet of debris flows and 

alluvium. 

Only two of these ash layers are known to have 

originated at Mount Rainier. Two other pyroclastic 

layers become progressively coarser and thicker toward Mount St. Helens, 50 miles to the south-southwest. These layers merge with the two sheets of 

pumice northeast of Mount St. Helens described by 

Carithers (1946, p. 16), who recognized that they 

were erupted by Mount St. Helens and were carried 

as far as Mount Rainier. 

The six layers are light colored and are prominent 

and individually distinctive. Because they were initially deposited over wide areas and are still locally 

preserved, they are useful for subdividing, correlating, 

and dating Recent surficial deposits. 

Study of the Recent pyroclastic deposits near Mount 

Rainier began during investigation of the Osceola 

Mudflow, and most of these six light-colored layers 

were described briefly in a section measured ~m the 

northeast side of the volcano (Crandell and Waldron, 

1956) : In the present study, the stratigraphy and 

distribution of the ash layers on and near Mount 

Rainier were studied by Crandell and Miller, and the 

stratigraphy of the pumice at Mount St. Helens and 

the petrography of the pyroclastic layers were examined by Mullineaux. Radiocarbon ages of interbedded organic matter were determined by Rubin. 

DESCRIPTION 

The 6 pyroclastic deposits include 3 composed 

chiefly of pumice of lapilli size or larger, and 3 of 

vitric and crystal ash. Most of the layers can be 

recognized in the field by color, size range, and stratigraphic position; laboratory study of constituent minerals and glass confirms field identifications and distinguishes those that appear outwardly similar. In 

many places these distinctive layers are separat~d by 

beds of dark sand, some of which probably are lithic 

ash from Mount Rainier. Arbitrary letter symbols are 

here assigned to the distinctive ash layers to permit 

future additions to the sequence without changes of 

nomenclature. The mineralogy, source, and age of 

the pyroclastic deposits are summarized in the following tables, and the deposits are compared with Recent 

events in the valleys of the Nisqually and White 

Rivers. 

LAPILLI AND ASH LAYER R 

Layer R consists of brownish-yellow (10YR 6/6) 

ash and lapilli as much as 30 mm in diameter and 

occurs in the north and east parts of the park. The 

lapilli are dark to light-brown andesitic pumice, 

cinders, and dense rock fragments which lie in an 

oxidized matrix of similar rock fragments and crystals. The glass in most la pilli is dark brown and 

turbid, and much of it is crowded with crystallites. 

The refractive index of glass in different fragments 

ranges from about 1.52 to about 1.57. 

Northeast of Mount Rainier layer R decreases 

from a thickness of about 6 inches 7 miles from the 

summit of. the volcano to 2lj2 inches 10 miles away. It 

was not seen on the southwest flank of ~{ount Rainier 

during detailed mapping there. Its coarse texture and 

apparent thinning away from the volcano in a northTABLE 138.1-Mineralogy of the pyroclastic layers 

Fe-Mg minerals 

Pyroclastic Source of pyroclastic Refractive Index 

layer material of glass Mineral I Abundance2 

Q _______ Unknown _______ hy D 1.52-1.53 and 

hb s. 1.49-1.50 

ag A 

w oxh s _______ Mount' St. hy D 1.49-1.50 

Helens. hb A c _______ Mount Rainier __ hy D 1.50-1.53 3 

hb s 

ag A 

y _______ Mount St. hy R 1.50-1.51 

Helens. hb D 

Q _______ ·Mount Mazama_ hy D 1.50-1.51 

hb A 

ag A R _______ Mount Rainier __ hy v 1.52-1.57 3 

hb v 

ag v 

oxh v 

1 by, hypersthene; bb, hornblende; a~, augite; oxh, oxyhornblende. 2 D, >50 percent; A, 5-50 percent; S, <5 but ubiquitous; R, rare; absent in some samples; V, varied. a In various pumice fragments. 

l 
f 

ARTICLE 138 D65 

TABLE 138.2-Age of pyroclastic deposits 

Correlative unit in 

PyrociMtlc Radiocarbon age and sample nos. 1 Inferred age of pyroclas- measured section of Principal events in valleys of Nisqually 

layer Source of pyroclastic material of organic matter (years) tic layers (years) Crandell and and White Rivers 

Waldron (1956) 

Recession of glaciers Q _________ Unknown ___________ -- - - - - 29<f ± -2oo- < w =-i i 2o > >65-<215 } 't:l 8 ~ w _________ Mount c:!rn St. Helens ___ -------3-2-o-± 2oo- c w=-i ii9 > 300 rn '"" ~g 

Advance of glaciers Oc;::l 

c _________ Mount c;::l>. Rainier_ _____ -----( -6-io-± _2_5_0_ ( w=-922)- 1,000-3,000 7 -~~ 

~c:l '""-

2, 550±200 (W-930) Cl);;. 

2, 980±250 (W-1118) 't:l~ 

3,200 6 oo ·y --------- Mount St. Helens ___ ---- 3~ 5oo-± 25o- < w=-ii is> ~s 

4, 000±250 (W-1116) sa.::: 

~~ o::::: 4, 800 ± 300 ( L-223A) ---------------- o _________ 5 Osceola M udflow o.c:: Mount Mazama _____ ---- s~ -75o-± 2so- < w =-9so)- R _________ Mount Rainier ____ -- ------------------------

1 W, U.S. Geological Sun'cy; L, Lamont Geological Observatory. 

easterly direction indicate that it originated in an 

eruptiori of Mount Rainier. The layer is well exposed 

:in a road cut 1.1 miles east of Sunrise Lodge at 

Yakima Park on the northeast side of ]\fount Rainier. 

Layer R underlies carbonized wood dated as about 

8,750 years old, but it postdates the glaciation of late 

'Visconsin age at ]\fount Rainier. 

ASH LAYER 0 

Ash layer 0 consists chiefly of light-yellowishbrown (10YR 6/4) to yellow (10YR 7/6) silt to sandsize pumiceous glass and crystals, and at .some. plac~s 

aggregates of iron oxide and clay. Particle~ In this 

nsh hnve an iron-oxide-rich film, beneath wluch crystals and glass are clear and seem to be unaltere~ .. 

The thickness of ash layer 0 near ]\fount Rainier 

ranges from 2 to 5 inches. The ash occurs all aroun.d 

the volcano but we have not attempted to trace It ' . beyond the park boundaries. It overlies layer R In 

road cuts at Yakima Park, where it is about 2 inches 

thick. 

Radiocarbon analysis of carbonized wood underly-

:ing layer 0 gave an age of about 8,750 years. In the 

White River valley, the ash underlies the 4,800-yearold Osceola Mudflow (Crandell and vV~ldron, 1956). 

According to 'Ray E. Wilcox, U.S. Geological Survey 

(oral communication, 1962) , the mineralogic and 

petrographic characteristics of ash layer 0 correspond 

closely to those of the pumice and ash from the eruption of Mount Mazama that formed the Crater Lake 

caldera in southern Oregon. This eruption is considered to have occurred about 6,500 years ago ('Villiams, 1953, p. 46). 

6,500 3 Cl) 

~ 

>8, 750 

LAPILL:I; AND ASH LAYER Y 

Layer Y in the park is a relatively thick deposit of 

dacitic pumice lapilli and vitric and crystal ash, and 

is generally very pale brown (10YR 7/4) to light 

yellowish brown (10YR 6/4). It is the most widespread, thickest, and most conspicuous of the Recent 

pyroclastic deposits at Mount Rainier. In addition, it 

is the only ash layer in these deposits in which pyi·oxene is rare. It is well exposed in a road cut adjacent to State Highway 5, 1.8 miles east of Ashford, 

'Vash., where it is 22 inches thick. 

A progressive decrease in grain size from south to 

north is apparent: 5 miles south of the summit the 

layer contains lapilli as large as 12 mm, and more 

than 30 percent of the deposit is larger than 1 mm, 

but 7 miles northeast of the summit the largest fragments are about 3 mm, and only about 5 percent of 

the layer is larger than 1 mm. Layer Y extends at 

least to Keechelus Lake (fig. 138.1) 25 miles northeast of Mount Rainier, where fragments as large as 

1 mm have beeri found. 

Layer Y is about 2 feet thick in the Nisqually 

River valley just west of the park, only 8 inches thick 

4 miles east of Elbe, and is absent. at Elbe. In addition, it is about 1 foot thick in all but the southeastern 

part of the park, where it is thin or absent. Southwest from ]\fount Rainier it increases markedly in 

grain size and thickness toward Mount St. Helens; 

near Randle it is as much as 4 feet thick and contains 

fragments as large as 3 inches. 

Its stratigraphic position, distribution, and southwesterly increase in size and thickness clearly indicate 
D66 

47 

N 

r 

GEOLOGICAL SURVEY RESEARCH 19 6 2 

122" 

A.MOUNT HELENS A."MOUNT ADAMS 

10 0 10 20 MILES 

Inferred extent of pumice layer C 

Inferred extent of lapilli and ash 

layer Y north of Mount St. Helens· 

FIGURE 138.1.-Inferred extent of ash and lapilli layers W, Y, and C. 

,.. 
ARTICLE 138 D67 

that layer Y is the same as the "older pumice" of the 

Cowlitz River va11ey described by Carithers (1D46, 

p. 16). Layer Y is not exposed on the flanks of 

Mount St. llelens, for the present cone postdates it. 

Ash layer Y is estimated to be about 3,200 years 

old: radiocarbon ages of about 2,500 and 3,000 years 

were obtained from organic matter above it, and ages 

of 3,500 and 4,000 years from below if (see table). 

PUMICE LAYER C 

By far the coarsest pyroclastic material in the Recent sequence is the pale-yellow ( 5Y 8/3) to olivegru.y ( 5Y 5/2) and black pumice layer C, which contains fragments as large as a foot in maximum dimension. This layer also contains dense lithic ash and 

lapilli. Glass in the most common pumice is andesitic 

(ref~·active index about 1.52-1.53), although fragments of dacitic glass have been found whose refra?-

tive index is between 1.50 and 1.51. The layer IS 

thickest and the pumice coarsest on the north and east 

sides. of Mount Rainier, where it was first described 

by Smith (1898, p. 418). The pumice is abundant at 

(Tround surface at Yakima Park, where fragments are b • 

as large as 2y2 inches in diameter. It commonly- Is 

8 to 12 inches thick as far as 12 miles from the summit of the volcano, but on.ly 4 inches thick 15 miles 

fr01n the summit. Scattered fragments as large as 

half an inch are present in the American River valley 

n,t a point 18 miles east of Mount Rainier. On the 

south and west sides of Mount Rainier the pumice decreases more abruptly in grain size and thickness, 

and generally it is absent more than 4 miles from the 

summit. At one locality on the south flank of Mount 

Rainier, material similar to layer C occurs in agglutiJUtted masses as large as 3 feet in diameter. 

Samples of pumice resembling layer C from the 

southwest flank of the volcano lack hornblende, although samples from the northeast side all contain 

at least small amounts of hornblende. Though not 

clearly established, the pumice lacking hornblende 

may represent a separate eruption. 

The hornblende-bearing pumice la.yer on the northeast side of the volcano has not been dated directly, 

but ns it occurs betw·een layers W and Y, its age is 

bracketed by dates .of about 300 and 3,200 years. No 

pumice was seen on a terrace in the White ~iver 

valley about half a mile downstream from the position of the terminus of the Emmons Glacier in 1910. 

This terrace is inferred ,to have been forested for at 

least 1,000 years (Sigafoos and 1Iendricks, 1961) ; 

thus, layer C presumably is older than 1,000 years. 

ASH LAYER W 

Ash layer W at Mount Rainier is a thin layer of 

coarse to very coarse sand-size dacitic pumice and 

smaller crystals, pumice, and glass shards; it ranges 

in color from white (2.5Y 8/2) to light gray (2.5Y 

7 /2) or pale yellow (2.5Y 8/4). It is generally recognizable by its size range, color, and thickness; a distinctive mineralogic feature is the high refractive 

index of its hypersthene (nx about 1.71) as compared 

to that of the hypersthenes in the other layers younger 

than layer R ( nx about 1.69). 

This ash· layer occurs in the eastern two-thirds of 

Mount Rainier National Park, and extends beyond the 

park boundaries in all directions except west and 

northwest (fig. 138.1). Layer W is almost continuSection measured in the east bank of Kautz Creek about 3,000 feet 

upstream from Wonderland Trail Bridge across creek 

21. Debris flow; boulders and cobbles in mediumto fine-sand matrix. Deposited in October 

Ft. in. 

. 1947 ___________________________________ _ 

20. Duff, silty, dark-grayish-brown; contains 

roots and wood fragments ______________ _ 

19. Boulders, 1 to 4 feet in diameter, in stratified 

coarse sand and granule matrix __________ _ 

18. Sand, fine to medium, gray, horizontally 

stratified and interbedded with layers of 

yellowish-gray silt ______________________ _ 

17. Duff; contains fragments of carbonized wood_ 

16. Silt and fine sand, yellowish-gray, horizontally bedded; contains pebbles and granules 

near top _____ - _ - - - -- ---- - - -- - - --- - - --- -

15. Duff and roots (radiocarbon sample W-1120, 

290 ± 200 years) ________________________ _ 

14. Sand, fine, gray _________________________ _ 

13. Ash layer W ____________________________ _ 

12. Sand, fine, gray _________________________ _ 

11. Duff, wood and carbonized wood fragments 

(radiocarbon sample W-1119, 320±200 

years) ________________________________ _ 

10. Sand, fine to medium, gray; contains scattered 

cobbles _______________________________ _ 

9. Debris flow; pebbles and cobbles in compact 

2-8 

3 

2 

sand and granule matrix; gray____________ 2 

8. Sand, medium, mostly horizontally stratified 

but has some faint crossbedding; contains 

reworked ash of layer Y, and wood fragments-------------------------------- 5 

7. Debris flow; boulders and cobbles in fine- to 

6 

2 

}~-}~ 

%-7'2 

}'z-2 

~ 

%-l}'z 

6 

medium-sand and granule matrix_________ 2 6 

6. Duff mixed with gray fine sand; contains fragments of charcoaL_____________________ }'2-2 

5. Sand, fine, gray; contains reworked pumice 

of layer Y, and wood fragments__________ %-2 

4. Debris flow; boulders as large as 4 feet in diameter in gray sand and granule matrix____ 15 

3. Sand, fine to medium, stratified, lenticular__ 1-3 

2. Lapilli and ash layer Y _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 8 

1. Pebble to boulder gravel and sand__________ 1. O+ 
D68 GEOLOGICAL SURVEY RESEARCH 19 6 2 

ously exposed adjacent to the highway between Longmire and Van Trump Creek in the park, where it is 

2 inches thick. The ash increases in thickness from 

about lj2 to 2 inches from the northern to the southern boundary of the park, while the ratio of coarse 

sand to finer sand increases from about 15 :85 to 40 :60. 

Southwest of the park, layer W continues to increase 

in thickness and grain size; near Randle, for example, 

it is several inches thick and contains pumice lapilli 

as large as 8 mm. On the north flank of Mount St. 

Helens, it is as much as 20 feet thick and contains 

pumice fragments 2 feet in diameter. Between Mount 

St. Helens and Mount Rainier, this layer is the 

younger, light-gray pumice deposit of Carithers 

(1946, p. 16). 

Radiocarbon analyses of carbon from duff layers 

just above and below ash layer W in the valley wall 

of Kautz Creek on the south side of Mount Rainier 

(see measured section) suggest an age of about 300 

years. 

ASH LAYER G 

Ash layer G is the youngest pyroclastic layer recognized at Mount Rainier and is a discontinuous layer· 

%, to lj2 inch thick in the modern forest duff. It consists principally of reddish-gray (lOYR 5/2) silt to 

very fine sand -size crystals, but also contains both 

brown turbid glass (refractive index about 1.52-1.53) 

and clear glass (about 1.49-1.50) that probably are 

andesitic and dacitic, respectively. It is distinguished 

from other ash layers by its color, fine size, stratigraphic position, and by containing a wider variety 

of dark minerals than other layers younger than 

lapilli and ash layer. R (see table). The variety of 

minerals and glass suggests the possibility that this 

layer contains ash from two volcanoes, perhaps Mount 

Rainier and Mount· St. Helens, but this has not been 

verified by other evidence. The ash overlies layer 

W along the highway between Longmire and Van 

Trump Creek in the park, where it is lj2 inch thick. 

The lateral extent of the ash is not known, although 

it seems to be absent west of the park. 

The ash is on a moraine formed about the middle 

of the 18th century, but is absent on a moraine formed 

about A.D. 1900. 

OLDER ASH LAYER OR LAYERS 

At least one partly oxidized crystal ash layer lies 

below layer R, and also postdates the last glaciation 

of Wisconsin age. This has been seen at only a few 

places, and its distribution, source, and stratigraphic 

relations are not well known, so that it cannot be 

said to be the deposit of a single ash fall. It is similar 

in color, thickness, and texture to ash layer 0, but 

differs in that it contains a markedly wider variety 

of minerals and larger proportion of crystals. Despite its age of probably more than 10,000 years, the 

older ash contains much clear glass. The fine texture 

of the layer suggests that it did not originate at 

Mount Rainier. 

CONCLUSIONS 

Preliminary work on Recent pyroclastic deposits on 

the flanks of Mount Rainier volcano indicates that at 

least 2 and probably 3 of the most distinctive, thickest, and most widespread layers were erupted by other 

volcanoes. The two pyroclastic layers originating 

from Mount Rainier are characterized by abundant 

andesitic glass and lithic fragments, and those derived 

from other volcanoes by dacitic glass. 

REFERENCES 

Carithers, Ward, 1946, Pumice and pumicite occurrences of 

Washington: Washington Div. Mines and Geology Rept. 

Inv. 15, 78 p. 

Crandell, D. R., and Waldron, H. H., 1956, A Recent volcanic 

mudflow of exceptional dimensions from Mount Rainier, 

Washington: Am. Jour. Sci., v. 254, p. 349-362. 

Mullineaux, D. R., and Crandell, D. R., 1960, Late Recent age 

of Mount St. Helens volcano, Washington: Art. 143 in U.S. 

Geol. Survey Prof. Paper 400-B, p. B307-B308. 

Sigafoos, R. S., and Hendricks, E. L., 1961, Botanical evidence 

of the modern history of Nisqually Glacier, Washington: 

U.S. Geol. Survey Prof. Paper 387-A. 

Smith, G. 0., 1898, The rocks of Mount Rainier: U.S. Geol. 

Survey 18th Ann. Rept., pt. 2, p. 416-423. 

Williams, Howel, 1953, The ancient volca~oes of Oregon, 2d 

ed. : Oregon State System of Higher Education : Condon 

Lecture Publications, 68 p. 
.~. 

~· 

ARTICLE 139 D69 

STRUCTURAL GEOLOGY 

139. THE PINE MOUNTAIN OVERTHRUST AT THE NORTHEAST END OF THE POWELL VALLEY 

ANTICLINE, VIRGINIA 

By RALPH L. MrLLER, Washington, D.C. 

The Pine Mountain overthrust underlies the entire 

Cumberland overthrust block in the tristate area of 

Virginia, l(entucky, and Tennessee. The block is rectangular in shape, 125 miles long from northeast to 

southwest, and 25 miles wide from southeast to northwest (fig. 139.1). On the northwest side of the block, 

coal measures of Pennsylvanian age are preserved at 

the surface in the Middlesboro syncline. On the 

southeast side, rocks as old as Middle Cambrian are 

exposed along the axis of the Powell Valley anticline. 

The stratigraphic position of the Pine Mountain overthrust, along which the block moved to the northwest, 

is now known at a number of different localities as a 

result of recent detailed geologic mttpping and from 

deep wells that cross the fault. Most of the deep 

drilling has been in the Middlesboro syncline in l(entucky and in the coal-bearing parts of adjacent Virg1nm where the fault is a bedding-plane fault near 

the base of the Chattanooga shale of early usage. 

Along the Powell Valley anticline the fault is exposed in central Lee County, V a. in fensters in the 

Rose Hill region (Miller and Fuller, 1954) and the 

Jonesville region (Miller and Brosge, 1954). Northeast of central Lee County, the fault is not known to 

be exposed nor have any wells been drilled that are 

known to have reached the fault. However, recent 

detailed mapping of the Big Stone Gap 71j2 -minute 

quadrangle that includes parts of Lee, Wise, and Scott 

Counties suggests that the fault zone comes to the 

surface in the valley bottom of Powell River southwest of the town of Big Stone Gap. Here a strongly 

deformed zone in the lower par,t of the Chattanooga 

shale of early usage is exposed just above the valley 

floor, and the deformed zone may be seen in a dozen 

\ 

\ 

\ 

SCOTT CO \ 

' 

VIRGINIA \ --~K.--~~,..;;.......1--------------.L...- TENNESSEE 

10 0 10 20 30 40 MILES 

EXPLANATION 

--------: 

Southeast margin of Pennsylvanian rocks 

of the Cumberland Plateau 

Thru!!t fault 

Barbs on upper plate 

High-angle fault 

Slwwing relative movement 

360~~~~~----~~----------------------------L-----------------------------_J------~360 .84° 83° 

FIGURE 139.1.-lndex map of the Cumberland overthrust block showing major structures, location of the Big Stone Gap 

quadrangle (shaded), location of the Rose Hill district (I), and location of the Jonesville district (2). 
D70 GEOLOGICAL SURVEY RESEARoCH 1 9 6 2 

82°52'30" 

36° 52' 30"r--------...----------------.....,...,,....-___,..... 

IPw 

Mp 

EXPLANATION 

Contact 

D 

u 

Fault 

U, upthrown side; 

D, downthrown side 

Thrust fault 

Barbs on upper plate 

Syncline 

3!!.l--

Strike and dip of beds 

6~ 

Strike and dip of 

overturned beds 

Defonned zone 

Mp 

82°45' 

2 MILES 

FIGURE 139.2.-Generalized geologic map of the Big Stone Gap quadrangle, showing the location of the deformed zone in the 

Chattanooga shale of early usage, and of structure section A-A' (fig. 139.3). Formations, shown by symbols, are as follows: 

Pw, Wise Formation; IPg, Gladeville Sandstone; Pn, Norton Formation; PI, Lee Formation; Mp, Pennington Group; Mbp, Bluefield Formation, Green brier .Limestone, and Price Sandstone; MDc, Chattanooga shale of early usage; DShc, sandstone (Helderberg 

as used by Stose, 1923), Hancock Limestone, Clinton Formation, and Clinch Sandstone; Osr, Sequatchie Formation and Reedsville 

Shale; Ot, Trenton Limestone; Oml, lower Middle Ordovician limestone formations; O£km, Knox Group and Maynardville 

Limestone. Localities 1 and 2 are exposures of black shale referred to in text. 
~· 

ARTICLE 139 D71 

outcrops. A line drawn on the map to enclose all 

these outcrops forms an elongate narrow area along 

the valley bottom stretching from a point along the 

Powell River opposite downtown Big Stone Gap 

southwest for 41)1, miles to a point about 11/2 miles 

northeast of the town 'of Olinger (fig. 139.2). The 

rrreatest width of this area is about 0.4 mile, but it b ' 

averages about 0.15 mile. 'Vithin the area thus delineated, every outcrop that could be found was of 

intricately deformed black shale assigned here to the 

lower part of the Chattanooga shale. No outcrops of 

any other formation were seen, nor was any of the 

bhtck shale within this area undeformed as it is in 

many other places in the Big Stone Gap quadrangle. 

One of the two largest exposures of the deformed 

black shale is .at the base of a nearly vertical bluff 

just above water level on the· south bank of the Powell 

River about 500 feet east of the Lee Count.y-vVise 

County line (fig. 139.2, loc. 1). Here the beds are 

nearly completely upside down, with deformed black 

shale at water level overlain by similar but uncleformed black shale of the lowest part of the Chattanooga, by sandstone (Helderberg as used by Stose, 

1923), and by Hancock Limestone CU pper Silurian) 

n.t the top of the bluff. The other very good exposure, 

n.lso in a nearly vertical bluff, is on the north bank of 

the Powell River below the Louisville and Nashville 

Railroad tracks, 3,200 feet clue west of where the 

county line crosses the Powell River (fig. 139.2, loc. 

2). Here the beds are right side up. Strongly deformed black shale at river level is overhtin by much 

less deformed black shale of t.he lower part of the 

Clutttanooga, which is overlain by undeformed, 

though steeply dipping, siltstone a.nd shale of the 

middle and upper parts of the formation. 

In both of these good exposures, nnd in the other 

10 much smaller ones, the shale is hackly instead of 

breaking along smooth surfaces. Slickensided carbonaceous surfaces are abundant, and changes of dip 

are extreme within a matter of a few feet or a few 

tens of feet. If the outcrop is big enough, small faults 

or well-developed chevron folds are visible. 

The "top" of the deformed zone along the valley 

rises only a few tens of feet ~tbove river level, so that 

it may be described as nearly flat in spite of the fact 

that older beds on the south side of the river and 

younger beds on the llOrth side of the river are steeply 

dipping, whether right side up or overturned. 

The Chattanooga shale has been mapped in many 

other places in the Big Stone Gap quadrangle. Only 

in the vicinity of the town of Jasper does it show the 

type of deformation described above, and here it is 

clettrly demonstrable that the Wallen Valley fault, a 

large Appalachian-type low-angle fault, is a beddingplane fault within the lower part of the formation 

(fig. 139.2). 

The evidence above has led the writer to postulate 

that another large low-angle fault lying entirely 

within the lower part of the Chattanooga shaJe comes 

to the surface south of the Powell River and dips 

downward beneath the surfa,ce again on the north 

side of the river. The outcrops that we see along the 

41)b -mile belt are parts of the deformed zone of this 

fault. The most logical fault to be present here is the 

Pine Mountain overthrust, which is known from broad 

regional evidence and from drilling to lie within the 

Chattanooga shale beneath the Middlesboro syncline. 

A structure section incorporating the above interpretation of the subsurface structure is presented 

here, reduced and generalized, as figure 139.3. The 

position of t.he section is shown in figure 139.2. In 

the section the Pine Mountain fault zone comes to 

the surface in the valley of the Po,Yell River and lies 

at shallow depths beneath Turkey Cove at the southeast, where numerous folds and faults in lower Middle 

Ordovician limestone formations suggest a major 

fault not too far below. These folds and faults are 

too small to show at the scale of figures 139.2 and 

139.3. The amount of displacement inferred on the 

Pine Mountain fault is about 2 miles as indicated by 

the offset of the ICnox Group in figure 139.3. As yet, 

no way has been found to measure or calculate ·the 

displacement in this region. The amount shown may 

be too small, but it is probably not too large. 

The Pine Mountain fault zone is shown on figure 

139.3 as a line, because of space limitations at the 

small scale of the section. Actually the line where 

it breaks the surface should be interpreted as representing the top of the deformed zone of the fault, 

rather than the plane or planes along which greatest 

movement occurred. No major fault plane was seen 

along the Powell River valley. The fault plane may 

be concealed beneath the river alluvium and colluvium 

of the lowest slopes of the mountains on both sides, 

or more likely it lies at shallow depth beneath the 

bedrock surface of the valley floor. 

According to the above interpretation of the deformed zone and the overthrust fault, a large anticline \Yould underlie the overthrust. Formations older 

than the Chattanooga would be present in normal order 

down ward to basement. In a direction normal to the 

section, the anticline in pre-Chattanooga rocks as well 

as the deformed zone would plunge gently beneath 

the surface both to the northeast and the southwest, 

thus form.ing a large closed structure. This anticline 

may extend far beyond the 41)b -mile distance along 

which the deformed zone is exposed. 
D72 GEOLOGICAL SURVEY RESEAR·CH 19 6 2 

______________ Ql ,_ 5 

/~ ~· --- ~ 

--- 'ii -- ~ -- 0 

A' 

Q..--------

0 2 3 MILES 

HORIZONTAL SCALE 

FIGURE 139.3.-Structure section along line A-A', figure 139.2. Formation symbols are the same as on figure 139.2 with the addition 

of the following subsurface formations: £c, Conasauga Shale; £pr, Pumpkin Valley Shale and Rome Formation. 

Two alternative interpretations of the subsurface 

structure have been considered. The first of these 

postulates that the fault deforming the Chattanooga 

shale in the Powell River valley is a much smaller 

branch of the Pine Mountain overthrust, which either 

rejoins the Pine Mountain fault somewhere beneath 

Stone Mountain or dies out northwest in the subsurface. The other interpretation, suggested by Leonard 

Harris (oral communication, 1962) , is that the deformation of the Chattanooga shale in . the Powell 

River valley is the result of very great compression 

of the shale in the core of a strongly overturned syncline, the analog of the faulted overturned anticline 

just south of the Powell River and on the north side 

of Turkey Cove (figs. 139.2 and 139.3). In either 

alternative interpretation, the main Pine Mountain 

fault would be nearly flat at a depth of about 3,500 

to 4,000 feet beneath Turkey Cove and would crosscut 

stratigraphically but not topographically upward 

from the base of the Maynardville Limestone to the 

Chattanooga shale beneath the Powell River valley 

and Stone Mountain. Neither of the two alternative 

interpretations seems to explain the features of the 

surface geology as satisfactorily as the interpretation 

diagrammed in figure 139.3, but lacking any subsurface data, the alternative interpretations cannot be 

eliminated. 

In the structure section shown here, the Trenton 

Limestone, which produces oil in central Lee County, 

is estimated to lie at a depth of 2,500 to 3,000 feet 

beneath Turkey Cove. In either of the alternative 

interpretations, the Trenton Limestone in the stationary block at the same location might lie about 6,000 

feet beneath the surface. 

Possibly additional mapping in the Powell Valley 

southwest and northeast of the Big Stone Gap quadrangle will shed more light on the location of the 

Pine 1\-Iountain overthrust within the quadrangle. 

Probably, however, the first and favored interpretation presented here can be verified only by drilling. 

If figure 139.3 is approximately correct in its major 

subsurface outlines, a well drilled along or a short 

distance south of the south edge of the Powell River 

valley would be an interesting test of oil and gas 

possibilities in the pre-Devonian formations. 

REFERENCES 

Miller, R. L., and Brosge, W. P., 1954, Geology and oil resources of the Jonesville district, Lee County, Virginia: 

U.S. Geol. Survey Bull. 990, 240 p. 

Miller, R. L., and Fuller, J. 0., 19,54, Geology and oil resources of the Rose Hill district-the fenster area of the 

Cumberland overthrust block-Lee County, Virginia: Virginia Geol. Survey Bull. 71, 383 p. 

Stose,, G. W., 1923, Pre-Pennsylvanian rocks, in Geology and 

mineral resources of Wise County and coal-bearing portions of Scott County, Virginia: Virginia Geol. Survey 

Bull. 24, p. 22-62. 

,1 

..... 
l 

)-

:,.. 

ARTLCLE 140 D73 

140. GRAVITY AND MAGNETIC ANOMALIES IN GEM VALLEY, CARIBOU COUNTY, IDAHO 

By DoN R. l\1ABEY and FRANK C. AmvcsTRONG, l\1enlo Park, Calif., and Spokane, 'V ash. 

In southeastern Idaho about 30 miles east of Pocatello, a northward-trending valley lies between the 

Portneuf n,nd Fish Creek Ranges on the west and the 

Chesterfield Range, Soda Springs Hills, and Bear 

R.iver Range on the east. The central part of this 

valley is called Gem Valley, and the northern and 

southern parts are known as Portneuf and Gentile 

Valleys, respectively (fig. 140.1). Gem Valley as used 

in this report includes Portneuf Valley and the north 

end of Gentile Valley. 

Gem Vn.lley is about 35 miles long and 7 miles wide. 

Elevations range frmn about 5,000 to 5,800 feet above 

sea level in the valley and to as high as 9,200 feet 

in the ranges. The divide between the Great Salt 

Lake drai~1age basin to the southeast and the Columbia 

River drainage basin to the northwest crosses the 

0 1 2 3 4 5 MILES 

111 °45' 

EXPLANATION 

--/70-

Gravity contours 

Contour interval 5 mgal8 

At------iA' 

Gravity profile 

B 1------l B ' 

Magnetic profile 

FIOUHE 140.1.-Bouguer-anomaly map of Gem Valley, and lines 

of profiles shown on 1igures 140.2 and 140.3. 

valley near its center. Bear River enters the valley 

from the east, bends sharply southward, and flows 

out the south end of the valley through a narrow 

gorge into Cache Valley and on into Great Salt Lake. 

The Portneuf River, which is a tributary of the Snake 

River, enters the valley at the north end and flows . 

out southwestward through a canyon on the northwest 

side of the valley. 

The central part of the valley is underlain by 

Pleistocene basalt lava flows. Prior to the extrusion 

of these flows Bear River is thought to have flowed 

northward in Gem Valley and to have left the valley 

by way of the Portneuf River canyon to join the 

Snake River. When the flows were extruded they 

apparently dammed Gem Valley and diverted the 

prelava Bear River, causing it to flow southward and 

·eventually to spill over into the Lake Bonneville 

drainage basin (Bright,1 p. 20~-246). Data presented 

here were obtained to determine if gravity and magnetic surveys could produce new data about the 

thickness of the basalt flows and underlying sediments _ 

in the valley that would bear on the valley's origin. 

GRAVITY SURVEY 

Gravity observations were made at about 150 stations in the valley and at a few stations in the nearby 

mountians. The data reduced to the simple Bouguer 

anomaly using an elevation correction of 0.06 mgals 

( milligals) per foot and contoured at a 5-mgal interval 

are shown in figure 140.1. The largest gravity feature is a low of about 35 mgals with the lowest values 

on the east side of the valley southeast of Chesterfield. A second area of low-gravity closure extends 

southward beyond the limits of the map and is separated from the northern low by a gravity high in the 

area of the topographic divide between Bancroft and 

Grace. 

The dominant local gravity anomalies in the Basin 

and Range physiographic province are produced by 

the density contr~st that usually exists between the 

Cenozoic rocks and the generally more dense older 

rocks. Smaller anomalies are produced by density 

differences within the pre-Cenozoic rocks and within 

the Cenozoic rocks. The rocks in the ranges adjoining Gem Valley are mostly sedimentary rocks of. 

Paleozoic age overlain locally by Tertiary sedimentary 

1 Bright, R. C., 1960, Geology of the Cleveland area, southeastern 

Idaho : Utah Unlv. Master's thesis, 262 p. 
D74 GEOLOGICAL SURVEY RESEARCH 1 9 6 2 

rocks. The· rocks underlying the cover of Quaternary 

alluvium and lava in the valley probably are Tertiary 

sedimentary rocks underlain by Paleozoic sedimentary 

rocks similar to those exposed in the ranges. As 

Mesozoic rocks had been largely stripped from the 

ancestral Be::tr River R::tnge by Early Cret::tceous time, 

it seems unlikely th::tt significant areas of Mesozoic 

rocks are preserved under the Quaternary alluvium 

and lavas of the central part of the valley, but some 

may be present in the northern part. 

Densities of the sedimentary rocks were not determined. A density contrast, however, of 0.4 or 0.5 g per 

cm3 between Cenozoic and pre-Cenozoic sedimentary 

rock has proved applicable in other areas of the Basin 

and Range province. The average density of 7 samples of basalt collected along Bear River is 2.64 g per 

cm3• This density is near the estimated density of 

the pre-Cenozoic rocks. As no large density contrast 

exists between the basalt and the pre-Cenozoic rocks, 

a thickness of a few hundred feet of basalt will not 

have an appreciable effect upon the large gravity lows 

in Gem Valley. 

The gravity anomaly on profile A-A' (fig. 140.2) 

across the northern low could be produced by a depression filled with material having a density 0.5 g 

per cm3 lower than tl1e enclosing rock and a maximum 

thickness of about 9,000 feet. The gravity low probably is produced mostly by Cenozoic sedimentary 

rocks; in the northern part of the valley l\1esozoic sedimentary· rocks may also contribute to the gravity low. 

The density of the Mesozoic rocks is probably greater 

than the Cenozoic rocks but less than the Paleozoic 

rocks. The lowest part of the northern low is coincident with a small topographic low on the basalt 

surface, which may indicate that subsidence of the 

valley has continued since the extrusion of the basaltA 

-165 

!/) -175 ..J 

< 

sa -185 ..J 

..J 

i -195 

__ ...... __ A' 

-165 

-175 !/) 

..J 

< -185 sa 

..J 

..J 

-195 i 

-205L---------------------------------~-205 

7000' 7000' 

SEA 

LEVEL 

-5000' 

0 2 3 4 5 MILES I I 

SEA 

LEVEL 

-5ooo·--

FIGURE 140.2.-'fhe gravity anomaly along profile A-A', in 

northern Gem Valley, and an interpretation of the gravity 

low. Density of material (shaded) beneath gravity low is 

0.5 g per cm3 lower than enclosing rock. 

a conclusion supported elsewhere by the presence 

of fault scarps in the basalt along the east side of 

Q-em Valley near the gravity divide in the valley. 

The steep gradients on both sides of the gravity low 

shown on profile A-A' (fig. 140.2) suggest that the 

deepest depression is bounded by normal faults on the 

east and west sides-a conclusion in agreement with 

Mansfield's (1929, p. 60) suggestion that the Chesterfield Range m::ty be a horst, and with recent work 

in the Bear River Range east of Gr~ce which also 

supports the theory of a horst-graben relationship for 

Gem Valley and the adjacent ranges. 

A gravity high which approximately coincides with 

the topographic divide separates the northern depression from a depression of similar size but undetermined eonfiguration near the center of the southern 

part of the vaJley. As it does not seem likely that 

the basalt flows can thicken enough over the topographic divide to aecount completely for the gravity 

high (a thickening of about 4,000 feet would be required), the gravity high is interpreted as a topographic high on the surface of Paleozoic rocks underlying the v::tlley. 

Because the density of the lava is very near that 

of the Paleozoic rocks in the ranges, gravity observations proved ineffective in determining the thickness 

of the lava where the Portneuf River leaves the valley. 

Only very detailed gravity surveys could possibly 

detect small gravity highs \Yhich might be associated 

with thickening of the lava in channels within the 

valley. 

MAGNETIC SURVEY 

The lava in Gem Valley is highly magnetic, in contrast to the almost nonmagnetic sedimentary rocks 

in the valley and adjacent ranges. Quantitative interpretation of the anomalies is difficult, however, because most magnetic anomalies associated with volcanic 

flows are produced in large part by remanent magnetism that usually has an erratic distribution. 

Seven total-intensity magnetic profiles were flown 

750 feet above the land surface in the valley (fig . 

140.3) . Over the flows the n1agnetic field is irregular 

but has no large changes in the general level of the 

field. The irregular character of the field is a good 

criterion for inferring the presence of basalt near 

the surface. The northern limit of the basalt is indicated on profile F -F' by the abrupt change in the 

character of the magnetic anon1alies .about 3 miles 

south ofF'. In this area the basalt thins northward, 

and as it is probably. only a few feet thick at its 

northern edge, the magnetic anomaly at the edge is 

not large. 

•-oo(l 
~·· 

~ 

~ 

ARTICLE 140 D75 

500 

D' 4oo G G' 

300 

200 

100 H' 

0 

0 2 3 4 5 MILES I I I I I 

FrGURE 140.3.-Aeromagnetic profiles of Gem Valley. Flight elevation was 750 feet above land surface. 

The magnetic fluctuation of several hundred gammas 

near the east end of profiles B-B', 0-0', and D-D' 

approximately coincides with the east margin of the 

basalt exposed in the valley. These large fluctuations 

indicate an abrupt termination of a thick basalt pile. 

The shape of the east end of profile E-E' and the location of E' suggest that E' is close to, but not east of, 

the east edge of the thick pile of basalt, as are points 

B', 0', and D'. Although profiles B-B' through E-E' 

are only half a mile apart only the larger magnetic 

fluctuations can be correln,ted between adjoining profiles. The high near the center of B-B', 0-0', and 

D-D' mn,y indicate an area of thicker basalt that 

filled a prebasalt topographic low over the deepest 

bedrock depression indicated by the gravity low. 

The magnetic high near the east end of profile H -H' 

and the stn,rt of a high at the east end of G-G' (fig. 

140.3) occur approximately over a group of basalt 

scoria cones and prominent collapse features in the 

(154685 0-62-6 

basalt. The cones and collapse features are alined so 

that they trend a little west of north and approximately parallel the west front of the Bear River 

Range and· the Soda Springs Hills at this locality. 

The trend of the cones and collapse features also approximately parallels a set of faults that cuts the 

basalts in the valley and the Paleozoic rocks in the 

ranges to the east. At the crest of the north end of 

the Bear River Range, basalt flows have been extruded from three centers located on similarly trending faults. The magnetic highs at the east ends of 

profiles G-G' and Ji-ll' are thus interpreted as indicating the position and trend of a fault zone along 

which basalt rose to the surface and furnished lava 

for some of the flows in the valley. 

REFERENCE 

Mansfield, G. R., 1929, Geogt·aphy, geology, and mineral resom·ces of the Portneuf quadt·angle, Idaho: U.S. Geol. 

Survey Bull. 803, 110 p. 
D76 GEOLOGICAL SURVEY RESEARCH 19 6 2 

141. GRAVITY, VOLCANISM, AND CRUSTAL DEFORMATION IN THE EASTERN SNAKE RIVER PLAIN, IDAHO 

By T. R. lh\.FEH.R and L. C. PAKISER, Denver, Colo. 

Work rlone in coope·mtion with the Aflvan.cerl He8C(trch Project:<; Agency, Depart·ment of Defense, a.<J 1Jart of project 

FEJ,A UNIFOUM 

A regional gravity survey in the eastern part of the 

Snake River Plain, Idaho, was made in 1961 as a 

continuation of the gravity network established by 

Ifill and others ( 1961) in the western part of the 

Snake River Plain. Seven hundred and seven gravity 

stations were established, and the measurements were 

reduced to the simple-Bouguer anomaly assuming a 

density of 2.67 g per cm3 for the rocks above sea level. 

The l'esulting data were plotted on a map and contoured at an interval of 10 milligals (fig. 141.1). 

'fhe Snake River traverses more than 400 miles from 

the Teton Mountains, Wyo., across southern Idaho to 

the Oregon-Idaho border. Over most of this course 

it follows the crescent-shaped, broad structural depression known as the Snake River Plain, most of whose 

19,000 square miles is north of the river. ·The plain 

115° 

44°30'. 

44°00' 

114° 

EXPLANATION 

Approximate boundary 

---of Snake River 

Plain 

can be divided into two parts, western and eastern, 

approximately along long 114°30' W. The western 

plain trends west and northwest; the eastern plain 

trends east and -northeast. 

The low gravity relief of the e·astern plain strongly 

contrasts with the high-amplitude anomalies of the 

western plain (Hill and others, 1961). There are four 

major gravity features in the eastern plain: (1) a 

broad high, which is an extension of the series of large 

gravity highs of the western.plain; (2) a set of elongated, alternating lows. and highs which trend normal 

to the axis of the eastern plain; ( 3) a series of small 

local highs on the southern and southeastern boundaries of the plain; and ( 4) a prominent low, centered 

over ~1ud Lake, in the northern part of the surveyed 

area (fig. 141.1) . 

113° 112° 111" 

~ Meeol [)r"port 42°30'~--~~--~------~~-+~~~~--~-4~----~~-------T----~----------~ 

10 20 30 40 50 MILES 

FIGURE 141.1-Simple Bouguer-anomaly map of the eastern Snake River Plain, Idaho. 

'"'( 
·~· 

ARTICLE 141 D77 

Snake Hiver Basalt of Quaternary age is exposed at 

the surface over almost all of the eastern plain. Because the steepest gravit.y gntdients occur over the 

mountains to the north and south of the eastern plain 

(in sorne pln.ces a considern.ble distance away from the 

edge of the basalt) it is presumed tha.t thes~ gradients, 

for the most p:trt, result from large-scale geologic features. The generalized regional gravity anomaly 

could be caused by a local upward displacement of the 

base of the earth's crust of about 6 k1n, from a normal 

crustal thickness of about 40 km. This estimate is 

based on depth estimation formulas (Bott and Smith, 

1958; LaFehr, 1962) and two-dimensional graticule 

analysis. 

RELATIONS OF GRAVITY AND GEOLOGY 

The alternttting lows and highs imply relatively 

near-surface geologic relief, although that relief may 

not be directly related to the mountains whose axes are 

cut nearly at right angles by the Snake River Plain. 

Of pttrticular structural importance is a widespread 

series of silicic volcanic rocks (largely rhyolite) of 

~{iocene or· Pliocene age that underlie the basalts of 

the Snake River Group. These silieic volcanic rocks 

occur in the mountains on both sides of the plain. 

Because they tend to dip toward the plain, Kirkham 

(1931, p. 471-481) concluded that the plain had been 

downwarped. Geologic and drilling information indicate that the rhyolite floor under the later basalt 

flows has considerable relief, which implies a variation in nenr-surface densities t'hnt could cause the 

gravity anomalies. With an assumed density contrast 

of about 0.3 g p~r cm3 between the bnsement complex 

a.nd the denser basalt, residual anomalies reveal thickness variations of the basalts of Quaternary age rnnging from a few hundred to as much as 5 thousand 

feet. 

The gravity low at Mud Lake (fig. 141.1) is attributed to an accuml.1lation of less than 2,000 feet of 

lacustrine deposits that crop out over a wide area in 

this part of the plain. This estimate is based on an 

assumed density contrast of -0.5 g per cm3• 

COlVIP ARISON OF THE EASTERN AND WESTERN 

PLAINS · 

The remarknble difference between the gravity fields 

of the eastern and western parts of the Snake River 

Plain demands a searching inquiry for 'other differences-geologic, topographic, or tectonic-which are, 

as yet, not established in the literature. The change 

in the gravity pattern occurs approximately where the 

nxis of the plnin is most strongly bent. The downwarp hypothesis (IGrkham, 1931), which has been 

ruled out for the "·estern plain (l\{alde, 1959; Hill and 

others, 1961), remains a possible explanation for the 

eastern pln.in. The eastern plain is tran~verse to the 

major topographic trends of the region. Fingerlike 

extensions of the mountain ranges face each other on 

opposite sides of the plain. The western .plain also is 

bordered by mountains, but their trends do not seem 

to be so distinctly broken by the plain. 

A study of earthquake epicenters in the United 

States (Woollard, 1958) outlines areas of recent tectonic activity. On the basis of these patterns, Mal de 

(1959, p. 272) states: "The crustal break implied by 

the gravity measurements is possibly expressed by a 

line of earthquake epicenters that extends diagonally 

from Puget Sound, .across the Columbia River 

Plateau, along the northern boundary of the western 

Snake Hiver Plain, and thence across the plain to 

northern Utah." This suggests a basic difference between the western and eastern plains: The western 

plain may be structurally controlled by a major break 

in the earth's crust; the eastern plain cannot be structurally controlled by this proposed break. 

The lava in the western plain probably escaped 

along or near this crustal break and along adjoining 

long fissures, giving the gravity field its en echelon 

character. The main channels of escape for the 

basalts of the eastern plain, in contrast, may be vents 

or short fissures, causing the circular and oblong gravity highs along the boundary. It may be significant 

that they are alined on the south and southeast boundary. It is perhaps along or near a fault, delineating 

this edge of the plain, that the magma found its 

escape. 

The extensive fissure flows that predominated in the 

early formation of the western plain probably filled 

a large graben. The formation of the eastern depression has almost certainly been accompanied by faulting, but the regional structural control of the western 

plain is seemingly not a factor in the depression of 

the eastern plain, as manifested in their different gravity fields, recent tectonic history, and topographic 

settings. The accumulations of basalt has been less 

in the east and has filled troughs or valleys in an 

undulating subsurface floor rather than a large regional graben. 

REFERENCES 

Bott, M. P. H., and Smith, R. A., 1958, The estimation of the 

limiting depth of gt·avitating bodies: Geophys. Prosp., v. 

6, no. 1, p. 1-10. 

Hill, D. P., Baldwin, H. L., and Pakiser, L. C., 1961, Gravity, 

volcanism, and crustal deformation in the Snake River 
D78 GEOLOGICAL SURVEY RESEARCH 1962 

Plain, Idaho: Art. 105 in U.S. Geol. Survey Prof. Paper 

424-B, p. B248-B250. 

Kirkham, V. R. D., 1931, Snake River downwarp: Jour. Geology, v. 39, no. 5, p. 456-482. 

LaFehr, T. R., 1962, The estimation of depth using gravity 

data [abs.] : Geophysics Yearbook, p. 267. 

1\:Ialde, H. E., 1959, Fault zone along northern boundary of 

western Snake River Plain, Idaho: Science, v. 130, no. 

3370, p. 272. 

\Voollard, G. P., 1958, Tectonic activity and earthquake epicenters : Am. Geophys. Union Trans., v. 39, no. 6, p. 1135-

1150. 

142. GEOHYDROLOGIC EVIDENCE OF A BURIED FAULT IN THE ERDA AREA, TOOELE VALLEY, UTAH 

By JosEPHS. GATEs, Salt Lake City, Utah 

Work done in. cooperation with the Utah State Eng·incc·r 

Differences in water-level fluctuations, chemical 

quality of ground water, altitude of the piezometric 

surface, and gravity on either side of a discontinuous 

i'idge that crosses the Erda area, in Tooele Valley, 

Utah, suggest that a fault causes a ground-water barrier at the ridge; the ridge probably is a surface expression of the fault. The fault may be a branch or 

extension of the Occidental fault (fig. 142.1) into 

112"30' 

45J 4o·r:====~~~====~~~~ 

EXPLANATION 

Normal fault 

DaBhed where inferred; 

dotted where concealed 

· Boundary of 

mountain range 0 5 MILES 

FIGURE 142.1.-Map showing the area described in this report, 

the Occidental and the Occidental ( ? ) faults, and· the Mill 

Pond and Box Elder Canyon faults as described by Thomas 

(1946). 

Tooele Valley, and it is termed the Occidental ( ~) 

fault in this article. Its position is inferred chiefly 

from the piezometric surface and from the surface 

ridge, and is shown in figure 14.2.2. The fault zone 

may cover a wider area than that shown, and the line 

of faulting may consist of 2 faults, 1 trending north 

and 1 trending northwest, instead of 1 curving fault. 

Gravity studies in Tooele Valley by W. W. Johnson 1 indicate a normal fault near the ridge, downthrown to the southwest, which is shown in figure 

142.2A for comparison. D. R. Mabey of the U.S. 

Geological Survey, who collected gravity data in the 

northern Oquirrh Mountains area, concludes (written 

communication, Dec. 27, 1961) ·that a fault trends a 

little west of north from the northwest corner of sec. 

28, T. 2 S., R. 4 W., although he doubts that this fault 

could be extended to the southeast on the basis of 

gravity data. 

The discontinuous ridge that crosses the Erda area 

from southeast to northwest (fig. 142.2A) contains 

gravel and boulders as large as 5 feet in diameter as 

:far as 31j2 miles from the front of the Oquirrh Mountains, in contrast to finer rnaterial that forms the surface on either side of the ridge. The gravel and 

boulders may have been deposited as a mudflow along 

the base of a fault scarp that since has been eroded. 

The deposit crops out prominently because the gravelly material is more resistant to erosion than the 

adjacent finer material. 

Ground-water conditions on opposite sides of the 

ridge differ considerably, as has long been known by 

local residents. Differences in the decline in water 

1 Johnson, W. W., 1958, Regional gravity survey of part of Tooele 

County, Utah: Utah Unlv. M.S. thesis, 38 p. 

r 

·~' 
~-

ARTICLE 142 D79 

T. 

EX PLANATION 

•• Y ........... . 0 

Normal fault inferred 

from gravity data 

U, upthrown side; D, 

downthrown side 

2 ~--+~:::e::....-4------h'YIY'--....::'k--t 

__ u ____ _ 

D 

s. 

T. 

2 

s. 

0 

\~0 

~·.U 

32 

8 

b. 17 

20 

32 33 

0 

A 

34 

1 MILE 

B 

Occidental(?) fault in- ferred from geologic 

and hydrologic data 

Dashed where in/erred; 

U, upthrown side; D, downthrown side 

EXPLANATION 

~ :z: 1000 .-Dissolved solids 

o. o. ~otal hardness 

~3 500 s If t ::s 0 u a e 

_u ____ _ 

0 Normal fault 

Dusked where in/erred; U, 

·upthrown side; D. downthrown side 

0 

Sampled well 

""'0 

Sampled spring 

levels on the two sides of the ridge during the 1959 

irrigation season indicated a ground-water barrier in 

the vicinity of the ridge. From spring to fall of 1959, 

the water .level northeast of the ridge declined 1.2 

feet in well a and 1.1 feet in well b (fig. 142.20). In 

contrast, southwest of the ridge the water level declined 9.3 feet in well c, 5.0 feet in well d, and 3.3 feet 

in well e. 

, 0 8 

0 

c 

EXPLANATION 

---4350-----

Piezometric contours 

Dashed where approximately 

located. Contour inte·rval 10 

feet; datum is mean sea level 

u --.0------ Normal fault 

·Dashed where inferred; U, 

upthrown side; D. down- thrown side 

oa Well used in determining 

piezometric surface 

Letter indicates well 

referred to. in text 

25 

FIGURE 142.2.-Map of the Erda area showing position. of the 

Occidental (?) fault relative to the following geologic and 

hydrologic evidence used by the author to infer the fault 

position : A, discontinuous ridge shown by contours and the 

position of a fault inferred by Johnson from gravity data, 

B, chemical character of representative samples of ground 

water, 0, piezometric surface as of June 1959. 

Chemical analyses of representative samples of 

ground water show a difference in quality of water 

on either side of the ridge (fig. 142.28). Ground 

water northeast of the ridge contains more dissolved 

mineral matter and it has an especially high hardness 

and sulfate content, compared to that southwest of the 

ridge. This difference in quality can be demonstrated 

only for water from aquifers at shallow depths because 

northeast of the ridge the analyses are of samples 

from a spring and from wells less than 140 feet deep. 

A map of the piezometric surface (fig. 142.20) indicates a ground-water barrier at or very near the 

ridge. In wells northeast of the ridge, the altitude of 

the piezometric surface is 50 to 70 feet lower than that 

in wells southwest of the ridge. Some of the difference 

may be a result of measuring water levels of deeper 

wells southwest of the riqge and shallower wells to the 

northeast, because in Tooele Valley the deeper artesian 

aquifers have higher water levels than the shallower 

artesian aquifers. However, water levels in some wells 

of about the same depth on either side of the ridge 

differ by 50 to 70 feet, so a lack .of hydraulic connection, and not a variation of well depths, is the cause of 

the large differences in water lev~ls. 

The discontinuous surface ridge intersects the 

Oquirrh Mountains near a range-front fault scarp 
D80 GEOLOGICAL SURVEY RESEAR<CH 19 6 2 

which is assumed to be the eastern limit of the trace of 

the fault through the Erda area (fig. 142.2A). Thomas 

(1946, p. 148) concluded that this scarp was an expression of the Occidental fault,- which had been defined 

in the Bingham mining district about 8 miles southeast of Erda. The trace of the Occidental fault 

(Cook, 1961, pl. 1) and the trace of the Occidental ( ~) 

fault through the Erda area are nearly parallel and 

almost join at the n1ountain front (fig. 142.1). Thomas 

( 1946, p. 149-150) considered the faults along the west 

front of the Oquirrh l\{ountains, which probably include the fault that passes through Erda, to be basinand-range type faults of Tertiary and Quaternary age. 

James, Smith, and Welsh (1961, p. 56), however, state 

that the Occidental fault in the Bingham district is 

older than the basin-and-range type faults. The offset 

in the valley fill that causes the ground-water barrier 

may represent a basin-and-range type of fault movement along the older Occidental fault. 

Thomas (1946, p. 147-152) described several faults 

in Tooele Valley, including the Box Elder Canyon 

and Mill Pond faults crossing the Erda area as shown 

on figure 142.1. Water-level and water-quality data 

collected in the present investigation, and Johnson's 

gravity data, suggest that the Box Elder Ca:i1yon fault 

does not cross Tooele Valley a~ong the projection of 

its surface trace in Box Elder Canyon as interpreted 

by Thomas. Also, the Mill Pond fault, instead of 

trending south from Mill Pond Spring as interpreted 

by Thomas, probably trends southeast from the spring 

roughly parallel to the Union Pacific Railroad tracks. 

Because the existence of the one and the location of the 

other are questionable they are not shown on figure 

142.2. 

The Utah State Engineer does not encourage the 

drilling of new wells in the Erda area because ground 

water in the area may be fully appropriated. Recognition of the Occidental ( ~) fault, however, may lead 

to additional ground-water development in the Erda 

area, because an increase in' withdrawal of water from 

the relatively undeveloped area northeast of the fault 

should not lower water levels in the more highly developed area southwest of the fault. 

REFERENCES 

Cook, D. R., ed., 1961, Geology of the Bingham mining district 

and northern Oquirrh Mountains: Utah Geol. Soc. Guidebook 16, 145 p. 

James, A. H., Smith, W. H., and Welsh, J. E., 1961, General 

geology and structure of the Bingham district, Utah, ·in 

Cook, D. R., ed., Geology of the Bingham mining district 

and northern Oquirrh Mountains : Utah Geol. Soc. Guidebook 16, p. 49-69. 

Thomas, H. E., 1946, Ground water in Tooele Valley, Tooele 

County, Utah: Utah State Engineer Tech. Pub. 4, in 

Utah State Engineer 25th Bienn. Rept., p. 91-238. 

143. RECURRENT MOVEMENT ON THE CANYON CREEK FAULT, NAVAJO COUNTY, ARIZONA 

By ToMMY L. FINNELL, Denver, Colo. 

The southwestern part of Navajo County, Ariz., lies 

within the Basin and Range physiographic province, 

but it is characterized, in general, by flat-lying sedimentary rocks which are continuous with the structurally simple rocks of the Colorado Plateaus province 

to the north. 

A major fault, here named the Canyon Creek fault, 

has been traced along strike for about 11 miles in 

southwestern Navajo County, (fig. 143.1) and it also 

extends southward for . about 30 more miles in Gila 

County (A. F. Shride, oral communication, 1962). The 

fault strikes generally N. 10° W. and is nearly vertical. For about 9 miles the fault is near the base of a 

rugged scarp facing westward on a broad valley occupied by Canyon Creek and Oak Creek. Near the 

south end of Chediski Farms, the scarp disappears and 

the fault follows the bed of Canyon Creek for about 

a mile. North of Chediski Farms the fault extends 

about a mile before it passes into a monocline. 

Evidence for two distinct periods of movement with 

opposite sense is observed along the Canyon Creek 

fault-the early movement raised beds of Pennsylvanian age on the west ; the later movement raised a 

gravel deposit and a basic flow of late Tertiary or 

Quaternary age on the east. 

The maximum stratigraphic throw on the Canyon 

Creek fault at Chediski Farms is about 840 feet upward· on the west. At the north end of Chediski 

T 
ARTICLE 143 D81 

0 5 MILES 

FIGURE 143.1.-Sketch map of the southwestern corner of Navajo County, 

Ariz. 1, Canyon Creek fault; 2, Lost 

Tank Cn.nyon fault; 3, Chediski Farms; 

4, Cliff House Canyon; 5, Spotted 

Mountain. 

Farms, the westward trending Lost Tank Canyon 

fault joins the Canyon Creek fault and absorbs about 

600 feet of the stratigraphic throw by downward displacement of the north block. About a mile north of 

the junction with the Lost Tank Canyon fault, the 

Canyon Cl.'eek fault passes into the anticlinal bend 

·of an eastward-dipping monocline, which has about 

600 feet of structural relief on the base of the Naco 

Formation (Pennsylvanian) . The Canyon Creek fault 

near Chediski Farms is clearly post-Pennsylvanian in 

age and it may be Laramide or younger. 

Southward from Chediski Far1ns the relative displacement on the fault remains upward on the west but 

the amount of throw diminishes gradually to about 

500 feet at Cliff House Canyon, where the Dripping 

Spring Quartzite (Precambrian) on the west is in 

fault contact with the Troy Quartzite (Precambrian) 

on the east. 

West of the fault on the south rim of Cliff House 

Canyon the Dripping Spring Quartzite is overlain by 

a gravel deposit of late Tertiary or Quaternary age, 

and this in turn is overlain by a basic flow about 60 

feet thick. The gravel beds are dragged to dips of 

80° w. along the fault, and the flow also seems. to be 

dragged, indicating that the block west of the fault 

has been downthrown. 

The basic flow west of the fault is very similar to a 

flow that rests on gravel on Spotted l\fountain about 

4 miles to the east, and, assuming that they are faulted 

portions of a single flow that covered a surface of low 

relief, the postflow displacement is about 1,300 feet 

upward on the east. The original upthrow on the west 

side of the Canyon Creek fault at this point, thus, may 

have been as much a.s 1,800 feet. 

Where the Canyon Creek fault has been traced in 

Gila County, by A. F. Shricle, gravel deposits of late 

Tertiary or Quaternary age are faulted upward on the 

east, and the deformation is considered to be the result 

of basin-range block faulting. 

The early movement on the Canyon Creek fault apparently displaced beds upward as much as 1,800 feet 

on the west. Later movement apparently displaced 

gravel deposits of late Tertiary or Quaternary age upward as much as 1,300 feet on the east. The late 

movement probably represents basin-range deformation which followed the previously established line of 

weakness northward into an area of Colorado Plateaus 

structure. 
D82 GEOLOGICAL SURVEY RESEARCH 1 9 6 2 

144. RESTUDY OF THE ARROWHEAD FAULT, MUDDY MOUNTAINS, NEVADA 

By C. R. LoNGWELL, Menlo Park, Calif. 

The Muddy Mountains, in .Clark County, Nev., have 

rugged relief developed on Paleozoic carbonate rocks 

in an extensive flat thrust plate. A steep scarp at the 

north side of the range marks the location of the 

Arrowhead fault, a structural east-west boundary between the high mountain mass and the lower ridges 

of the North Muddy Mountains (fig. 144.1). These 

ridges, e.xtending northward to the valley of the Muddy 

River, are developed on a structural pattern radically 

different from that south of the Arrowhead fault 

(Longwell, 1949, pis. 1, 5). A belt of large folds, in 

part recumbent, extends from the Arrowhead fault 

northward through the western part of the North 

Muddy Mountains. 

An early study of the area led to conviction that 

movement on the Arrowhead fault had an important 

left-lateral component (Longwell, 1928, p. 110-111, 

pl. 1, fig. 6) . That interpretation regarded the steep 

fault as genetically related to the thrust and associated folds, serving to accommodate differences in 

Tmc 

MUDDY MOUNTAIN THRUST '\. PLATE · : : : : : : : 

Contact 

--+--+ 

Anticline, showing plunge 

(Paleozoic carbonate rocks) 

0 

Normal fault, showing dip 

Daslutd wlutre inferred 

Strike and dip of beds 

2 3 

--4'-

4 5 MILES 

................ ~ 

Thrust fault 

Barbs on upper plate 

-4-

Strike and dip of 

overturned beds 

Strike and dip of beds turned 

through more than 180° 

- / ........ .. 

c•••••QT••• 

I I I I I ltl I I I I I 

Steep reverse fault 

Hachures on downthrown side 

-+-

Strike of vertical beds 

FIGURE 144.1.-Major structural features in the Muddy Mountain area. £ and 0, rocks of Cambrian and Ordovician(?) age; 

D, Devonian carbonate rocks; M, JViississippian carbonate rocks; PPc, Callville Limestone (Permian and Pennsylvanian); 

Prb, Permian red beds; Pk, Kaibab Limestone (Permian); "R, Triassic rocks; Ja, Aztec Sandstone (Jurassic?); Ks, Cretaceous 

sedimentary rocks; Ths, Horse Spring Formation (Tertiary); Tmc, Muddy Creek Formation (Tertiary); QT, Quaternary and 

Tertiary deposits; G, remnant of Glendale thrust plate. 

/--. 

T 

r 
ARTICLE 144 D83 

s ~-----CAMBRIAN-----~ CAMBRIAN(?) ~---ORDOVICIAN(?)---~ S' 

Bonanza King Formation 

t;ti 

::J('(J • ._ C: Lower dolom1te 

~0 

1-u 

3200'---~ 

Aztec Sandstone 

(JURASSIC?) 

0 1000 

Dolomite 

2000 

Yellow-gray dolomite; 

chert at many horizons 

z 

~ 

z 

0. 

> UJ 

Q 

NNE 

3000 FEET 

}i'rouRE 144.2.-Structure section across the monocline at west end of Arrowhead fault (on line S-S', fig. 144.3). 

deformation in adjacent major blocks. Pa.rts of the 

structural pattern seem to indicate strong strike-slip 

movement. In the North ~{uddy ~fountains, structural elements that trend generally north bend toward 

the southeast as th~y are traced toward the Arrowhead fault. This suggestion of drag effect from leftlateral movement is partic"!.llarly i1npressive in the 

Summit thrust block, at the southwest border of the 

Valley of Fire. 

A detailed study of the North Muddy Mountains 

revealed that near the west border of the range the 

Arrowhead fault passes into a steep monoclinal fold 

(Longwell, 1949). North of this fold, formations that 

1nake up the 1\iuddy Mountain thrust plate are overturned beneath a thrust at a higher structural level, 

the Glendale thrust. Scattered remnants of the Glendale thrust plate overlie much-deformed younger 

strata in a belt extending more than 20 miles to the 

north. 

The dying out of the Arrowhead fault in the monocline h:ts important implications to be considered in 

analysis of the overall structural pattern. As the 

major blocks north n.nd south of the fault are united 

in the monocline, the suggestion of large-scale strikeslip movement on the fault must be illusory. Such a 

component of movement would be possible only to the 

extent that deformation by folding or thrusting may 

have shortened the block on one side of the fault relative to the adjacent block. Thrusting and folding in 

the western part of the North Muddy Mountain belt 

perhaps caused enough local shortening to account for 

a limited strike-slip component on the fault. 

Another important deduction from the union of 

blocks in the monocline concerns the northward extent 

of the Muddy Mountain thrust. Directly south of the 

Arrowhead scarp the plate was displaced, relatively 

eastward, through the full width of its present exposure. The do~n-dropped part of the plate north of 

the fault must have 111oved eastward with the block to 

which it is attached in the monocline. Therefore the 

Muddy Mountain thrust must extend an unknown distance northward beneath a concealing cover of sedimentary formations (Longwell, 1949, p. 938, 940). 

In the fall of 1961, with Leonard Palmer as field 

assistant, I began remapping the ~{uddy Mountain 

area on the topographic sheets now available. 'Ve 

gave particular attention to the Arrowhead fault and 

monocline. The valley of a stream that winds through 

the area of the monocline provides almost perfect exposures of the stratigraphic units (fig. 144.2). Sections measured in detail across the monocline agree 

closely with sections measured in the thrust plate east 

of the Buffington window; this agreement is in the 

succession of distinctive stratigraphic units, and in 

total thickness. The earlier map (Longwell, 1949, 

pl. 1) errs in extending the Arrowhead fault considerably too far west; the section exposed in the monocline is intact through a distance of at least a mile 

inside the border of the range. Farther east there is 

increasing displacement on the Arrowhead reverse 

fault, with cutting out ·of successive formations north 

of it (fig. 144.3). 

Displacement on steep faults northeast of the Buffington window has played a part in adjustment from 

large upthrow on the Arrowhead fault to strong bend-· 

ing in the monocline. A northeast-trending fault 

against which the folding ends probably was itself 

deformed under pressure, as suggested by abrupt 

changes in its strike and dip. West of this fault a 

part of the monocline hooks strongly southward, with 

much local bending and fracturing. Displacement qn 

the fault dies out rapidly southwestward toward the 

east margin of the window, where it intersects a normal fault along which rocks of the thrust plate have 
D84 GEOLOGICAL SURVEY RESEAR-CH 19 6 2 

Contact 

Normal fault, showing dip 

Dashed where approximately located 

__&0 

Strike and dip of beds 

0 2 MILES 

CONTOUR INTERVAL 200 FEET 

. . . . ,... ..... ,.....,... 

Thrust fault 

Barbs on upper plate 

#-

Strike and dip of 

overturned beds 

I I I I I ll'l I I I I I 

Steep reverse fault 

Hachures on downthrown side 

+ 

Strike· of vertical beds 

FIGURE 144.3.-Map showing details of structure near west end of Arrowhead fault. £bk, Bonanza King Formation; £d, 

Dunderberg Shale; £u and Ou, unnamed units of Cambrian(?) and Ordovician.(?) age; D, Devonian carbonate rocks; Mrs, 

Rogers Spring Limestone (Mississippian); lim, Moenkopi Formation (Triassic). Other symbols for formations, and also 

structure symbols, as in figure 144.1. S-S', approximate line of structure section, figure 144.2. 

been dropped against Aztec Sandstone. East of this 

.normal fault the base of the plate and the underlying 

sandstone are exposed locally in two valleys. 

North of the Buffington window, where successive 

formations in the Muddy Mountain plate dip steeply. 

northward, units of Devonian and later age are overturned eastward beneath the Glendale thrust (fig. 

144.3). A conspicuous bend in strike of the older form'ations from west to northwest and north indicates 

that these units also were transected and upturned in· 

the Glendale thrusting. As these overridden formations constitute the Muddy Mountain plate, clearly the 

Glendale thrust is at a higher structural level. A 

westward divergence in strike along the monoclinal 

axis results from intersection by the monocline of two 

structural. units very different iri. character. In the 

Muddy Mountai·n plate, bedding is essentially parallel 

to the surface of thrusting. Where this planar unit, 

dipping westward, is bent strongly down along an 

east-west axis, the resulting pattern is a sharp curve 

in strike southward from the monocline. But northward tilting of formations that were turned up be-

.~ 

T 
_,, ~ 

ARTICLE 144 D85 

1 MILE 

.F'IGURE 144.4.-General relation, in section, between the Muddy 

Mountain thrust and the Glendale thrust, northwest of the 

Buffington Window. MM, base of Muddy Mountain thrust 

plate. Other symbols as in figures 144.1 and 144.3. 

neath the Glendale thrust, followed by erosion, has 

produced the pattern with curvature northward from 

the axis. 

The Glendale belt of thrusting and folding must 

have extended farther south, above the area of the 

Buffington window. After the two major thrusts were 

displaced by the Arrowhead fault and monocline, erosion removed the higher structure from the area- of 

uplif.t. If the Glendale thrust is extrapolated from 

the southernmost exposure of the plate, it should extend southwestward beneath the cover of alluvial deposits west of the range, .where presumably it transects the Muddy Mountain thrust (fig. 144.4). 

Study of a large and complex structural unit should 

consider all reasonable possibilities of origin and history. An obvious hypothesis may assume the Arrowhead fault to be a normal fault with downthrow on 

the south. Under this concept the North Muddy 

~fountains would represent a footwall block from 

which the Muddy Mountain thrust plate was eroded 

following uplift. The concept fails under several tests, 

one of them involving the monocline north of the 

Buffington window. Passing of a south-dipping normal fault into a flexure should result in a monocline 

dipping southward, not northward. Moreover in excellent exposures along the fault east of the monocline, 

beds on the north are bent sharply upward, testifying 

in convincing fashion to reverse movement against 

strong frictional resistance. Evidence of this kind is 

cumulative in a detailed study of the fault zone. 

The pattern that suggests important left-lateral movement on the Arrowhead fault merits analysis. Flexures that trend northwest in the high Muddy Mountain mass south of the fault imply that such trends 

may have been common, before the fault was in operation, in a wide belt that included the Summit block 

and neighboring ridges. Probably the pronounced 

curvature at the southeast end of the Summit ridge 

and similar structural details in neighboring ridges 

reflect northward pressure, while the fault was active, 

against blocks in which northwest trends were the 

result of earlier deformation. 

Exposures in the embaym,ent known as Fire Alcove, 

9 to 10 miles east of t~e Buffington window, have particular interest. There the thrust plate, on Aztec 

Sandstone, has the same succession of stratigraphic 

units of Cambrian age found in the lower part of the 

plate at the west side of the range. Bedding in the 

plate is essentially parallel to the thrust contact. The 

plate and the underlying Aztec Sandstone of Jurasisic( n age dip steeply southward from the Arrowhead 

fault. Along the fault the sandstone is in contact 

with formations of Triassic age. It is clear, therefore, that displacement on the Arrowhead fault is not 

restricted to the thrust plate, as was assumed in the 

concept that movement on the fault was largely 

strike-slip and genetically related to the thrusting. 

The throw on the steep reverse fault north of Fire 

Alcove, as reckoned from thicknesses of the tFansected 

formations, exceeds 10,000 feet (Longwell, 1949, fig. 7, 

p. 940). 

REFERENCES 

Longwell, C. R., 1928, Geology of the Muddy Mountains, Nevada: U.S. Geol. Survey Bull. 798, 152 p. 

-- 1949, Structure of the northern Muddy Mountain area, 

Nevada : Geol. Soc. America Bull., v. 60, p. 923-968. 
D86 GEOLOGICAL SURVEY RE.SEAR'CH 19 6 2 

145. CORRELATION OF GRANITIC PLUTONS ACROSS FAULTED OWENS VALLEY, CALIFORNIA 

By DoNALD C. Ross, Menlo Park, Calif. 

ll'ork rhmc 'in COOJJCrat-ion 1fjith the Oalifonlia DiV"i:•lio'n of M-ines anrl Geology 

This article presents evidence for the correlation of 

the Santa Rita Flat pluton in the Inyo Mountains 

with the Tinemaha Granodiorite, of Cretaceous age, 

in the Sierra Nevada (Bateman, 1961). Such a correlation places a limit on the amount of .lateral movement along the faults that bound or lie beneath Owens 

Valley. 

Geologic mapping in the east-central Sierra Nevada during the past several years has focused attention on correlating areally separate granitic masses 

within the composite Sierra Nevada batholith. The 

most recent product of this work is a report by Bateman ( 1961) in which he established several formal 

granitic formations in the Bishop area. 

Bedrock in the Inyo Mountains, across Owens Valley from the Sierra, consists predominantly of Paleozoic sedimentary ·rocks into which are intruded granitic plutons, some of batholithic proportions. In the 

Independence quadrangle, D. C. Ross, F. K. Miller, 

and R. J. Pickering have delineated several large plutons, one of which, the Santa Rita Flat pluton, bears 

a close resemblance to the Tinemaha Granodiorite of 

the Sierra Nevada (fig. 145.1). Examination of these 

two masses in the field and comparison of modal and 

chemical data suggest that they are correlative. This 

is the first time that a single lithologic unit has been 

correlated across Owens Valley, although broad correlations based on the regional pattern have been proposed (Bateman and others, 1962). Folded Paleozoic 

sedimentary and Mesozoic volcanic strata of the Inyo 

Mountains strike obliquely across Owens Valley toward the Sierra Nevada and may be correlative with 

metamorphosed remnants of grossly similar lithologies 

in the Sierra Nevada. Moore and Hopson ( 1961) 

have also suggested that a swarm of mafic d~kes in 

the eastern Sierra is correlative across Owens Valley 

with similar dikes on strike in the southern Inyo 

Mountains. 

The criteria for correlating areally separated granitic plutons are: ( 1) similarity of appearance-in 

particular similarity of textures and structures; ( 2) 

similarity of composition; and (3) compatible intrusive relations, and hence similar age. 

The textural and mineralogical similarity of the 

Santa Rita Flat pluton and the Tinemaha Granodiorite is striking. Both masses ·have about the same 

percentage of dark minerals and a range in grain size 

of 2 to 5mm. Both contain widespread tabular to 

equant phenocrysts of K-feldspar as long as 2 em, 

which have irregular borders and are commonly studded with dark minerals. Scattered relatively well 

formed hornblende crystals that are generally 1 to 2 

em long are characteristic of the Santa Rita Flat pluton, P,nd were also observed in outcrops of the Tinemaha Granodiorite. Lenticular mafic inclusions in 

the Tinemaha Granodiorite, described by Bateman 

( 1961) as numerous and defining a foliation, are widespread in the Santa Rita Flat pluton, but they are 

rarely abundant and only locapy define a foliation. 

The compositional similarity and the similar average specific gravity of these two masses also suggest 

118° 30' 118° 15' 118°00' 

3 7 ° 15',----------,~---~.--,------------. 

MT PINCHOT 

QUADRANGLE 

0 5 

QUADRANGLE 

\ 

0 

EXPLANATION 

~ Q 

Tinemaha Granodiorite Santa Rita Flat pluton 

FIGURE 145.1.-Map showing outcrop area of Santa Rita Flat 

pluton and Tinemaha Granodiorite. Faults along whtch 

there was movement in the 1872 earthquake in Owens Valley 

are shown as heavy black lines. Location of chemically 

analyzed samples is shown by small circled dots. 

_j 
~""·' 

ARTICLE 145 D87 

TABLE 145.1.-.Modal data of Santa Rita Flat phtton and 

Tinemaha Granodiorite 

Plngioclnse _________________________ _ K4cldspnr _________________________ _ Qunrtz ____________________________ _ 

Biotite ____________________________ _ Hornblende ________________________ _ Other _____________________________ _ 

A vernge specific gmvity _____________ _ Hornblende: biotite. _________________ _ 

Dn,rk-mineral content (color index) ____ _ 

1 In volmno percent. a Data on average mode from Bateman (1961). 

Average modes 1 

Santa Rita Tinemaha 

Flat pluton Granodiorite a 

36 

31 

20 

4 

6 

3 

2. 70 

1. 5: 1 

13 

42. 3 

24. 5 

19. 2 

4. 6 

6. 0 

3. 4 

2. 72 

1. 3: 1 

14 

correlation. Abundant modal data show that the 

two bodies have similar percentages of quartz, biotite, and hornblende, but somewhat different percentages of plagioclase and !(-feldspar (table 145.1). 

IIornblende in excess of biotite, which is characteristic of both bodies but quite unusual in rocks of the 

ceptral Sierra Nevada, is a key factor in the suggested correlation. 

The triangular plots of individual modes on figure 

145.2 (points show quartz, plagioclase, and !(-feldspar 

recomputed to ~00 percent) show that although the 

Santa Rita Flat pluton has a more restricted compositional range and· relatively more !(-feldspar than 

the Tinemaha Granodiorite, the modal field of the 

Santa Rita Flat pluton encloses nearly two-thirds of 

the modal plots of the Tinemaha Granodiorite specimens. 

Chemical data (table 145.2 and fig. 145.3) are limited to only two analyses from each mass, and these 

analyses are not of average specimens in the sense of 

having modes near the centers of their respective 

modal fields. Caution must be observed therefore in 

using the limited chemical data to draw conclusions 

about these granitic masses whose modal, and hence 

compositional, range is great. It seems reasonable to 

conclude, however, that though the chemical data 

neither confirm nor deny correlation, they are compatible with the correlation of these masses. 

The intrusive reln.tions, and hence the age relations of these masses, cannot be compared because the 

Santa Rita Flat pluton is not in contact with other 

granitic plutons. Both masses, however, are cut by 

abundant dark-colored dikes of the type described by 

Moore and I-Iopson (1961). 

In summary, each of the two masses discussed here 

has persistent mappable characteristics. Further, the 

similarity of the masses suggests that both are part of 

an originally continuous granitic intrusive, though the 

Modes of chemically analyzed specimens Average modes 

0 Santa Rita Flat pluton 

X Tinemaha Granodiorite 

• Santa Rita Flat pluton 

0 Tinemaha Granodiorite 

K-feldspar 

PLOT OF AVERAGE MODES AND MODES OF 

CHEMICALLY ANALYZED SPECIMENS 

Plagioclase 

SANTA RITA FLAT PLUTON 

TINEMAHA GRANODIORITE 

Outline of modal field of 

Santa Rita Flat pluton 

K-feldspar 

PLOT OF INDIVIDUAL MODES 

l!"!GUI~E 145.2.-Plots of model data of the Santa Rita pluton 

and Tinemaha Granodiorite. Data on individual modes are 

from Bateman (written communication, 1962). 

connection may be at some depth. The overall northwest trend of the two plutons (fig. 145.1), parallel to 

the regional trend of many granitic masses in the 

central Sierra, suggests a present-day connection beneath the Cenozoic deposits of Owens Valley. However, the several-mile gap between the easternmost 

outcrops of Tinemaha Granodiorite and the Santa 

Rita Flat pluton precludes more than speculation on 
D88 GEOLOGICAL SURVEY RESEA~CH 19 6 2 

TABLE 145.2.-Chemical analyses and norms of Santa Rita Flat 

pluton and Tinemaha Granodiorite 

I SRF-11 I SRF-2 I I 'l'in-1 2 I Tin-2 3 

CHEMICAL ANALYSES 

Si02------------------- 66. 4 61. 3 

AbOa------------- ----- 14. 9 15. 9 

Fe20a----- _------------ 2. 6 3. 1 

FeO-----------~------- 2. 0 3. 0 

~agg_ ~ = = = = = = = = = = = = = ·= = = = 

1. 6 2. 2 

3. 9 5. 3 

Na20------------------ 3. 0 3. 3 

K20------------------- 4. 1 3. 4 H2o ___________________ 73 85 

Ti02------------------- 48 64 

P20s------------------- . 26 36 ~no __________________ 08 10 

C02------------------- 05 05 

NORMS 

Q _____________________ 2:3. 5 15. 7 or _____________________ 24. 5 20. 0 

ab---------------~---- 25. 2 27. 8 an _______ . ____________ 15. 0 18. 6 di _____________________ 2. 0 4. 0 hy ____________________ 3. 9 5. 6 mt ____________________ 3. 7 4. 4 il _____________________ .9 1. 2 

ap ____________________ 7 1. 0 TotaL ___________ 99.4 98. 5 

Normative plagioclase ___ Ana7 An4o 

62. 82 

15. 44 

2. 59 

3. 17 

2. 35 

5. 04 

3. 15 

3. 72 

65 

64 

30 

11 

01 

16. 69 

22. 20 

26. 71 

16. 68 

5. 16 

6. 18 

3. 74 

1. 22 

69 

99. 27 

An as 

65. 77 

14. 34 

2. 10 

2. 62 

2. 02 

4. 24 

3. 18 

3. 76 

. 56 

. 60 

. 24 

. 10 

. 08 

21. 42 

22. 24 

27. 25 

13. 34 

5. 66 

4. 32 

3. 02 

1. 22 

. 34 

98. 81 

I Rapid rock analysis. Analysts: P. L. D. Elmore, I. H. Barlow, S. D. Botts, 

G. Chloe. 

2 Standard rock analysis (Bateman 1961, p. 1525-1526.) a Standard rock analysis (Bateman, written communication 1962). 

this point. Also, at least minor disruption of the 

postulated originally continuous body must have occurred along the trend of the 1872 earthquake faults. 

The correlation of these plutons across Owens Valley affects interpretations of the structural history of 

the region. Hill ( 1954, p. 10) suggests that Owens 

Valley may be the course of a major strike-slip fault. 

More recently Pakiser ( 1960) invokes strike-slip movement to help account for the origin and distribution 

of Cenozoic volcanic rocks in Owens Valley. Strikeslip faulting undoubtedly took place along some of 

the faults shown on figure 145.1 during the Owens 

Valley earthquake of 1872; however, Bateman ( 1961, 

p. 493) suggests that strike-slip movement was subQuartz 

Plagioclase 

e Santa Rita Flat pluton 

0 Tinemaha Granodiorite 

Orthoclase 

FrauRE 145.3.-Plot of normative quartz, orthoclase, 

and feldspar. 

ordinate to dip-slip movement in the Cenozoic structural development of the region. ::Moore and Hopson 

(1961, p. 258) suggest a limitation on strike-slip movement in Owens Valley of a few miles at most since 

Cretaceous 'time, based on the strike continuation of a 

swarm of mafic dikes across the valley. The correlation of the Santa Rita Flat pluton with the Tinemaha Granodiorite supports the view that strike-slip 

movement along the present course of Owens Valley 

is limited to a few miles at most since the emplacement of the Sierra Nevada batholith. 

REFERENCES 

Bateman, P. C., ·1961, Willard D. Johnson and the strike-slip 

component of fault movement in the Owens Valley, California, earthquake of 1872 : Seismol. Soc. America Bull., 

v. 51, no. 4, p. 483-493. 

Bateman, P. C., Clark, L: D., and others, 1962, The Sierra. 

Nevada batholith-a synthesis of recent work across the 

central part: U.S. Geol. Survey Prof. Paper 414-D. (In 

press) 

Hill, M. L., 1954, Tectonics of faulting in southern California, 

·in .Jahns, R. H., eel., Geology of southern California: California Div. Mines Bull. 170, chap. 4, pt. 1, p. 5-13. 

Moore, .J. G., and Hopson, C. A., 1961, The Independence dike 

swarm in eastern California: Am . .Jour Sci., v. 259, p. 

241-259. 

Pakiser, L. C., 1960, Transcurrent faulting and volcanism in 

Owens Valley, California: Geol. Soc. America Bun., v. 71, 

p. 153-160. 

,l 

r 

.... 
::1, 

ARTICLE 146 D89 

146. STRUCTURAL CONTROL OF INTERIOR DRAINAGE, SOUTHERN SAN JOAQUIN VALLEY, CALIFORNIA 

By GEonm~ I-I. DAvis a.nd J. H. GREEN, 'Vashington, D.C., and Sacramento, Calif. 

The southern part of the San Joaquin Valley, under the present water regime, is a basin of interior 

drainage. The streams tributary to the southern part 

of the valley drain to natural sumps in the center of 

the San Joaquin Valley, the largest of which is called 

Tulare Lake Bed. The low point of Tulare Lake Bed 

is 178 feet above sea level; the divide to the north is 

210 feet above sea level (fig. 146.1). Before the first 

diversions for irrigation about 90 years ago, the area 

was not permanently a basin of interior drainage. 

During periods of high runoff, Tulare Laln~ would fill 

to an elevation of 210 feet and would discharge north 

.to the San Joaquin River and thence to the Pacific 

Ocean. Playas or salt flats did not form because 

through-flowing water periodically flushed out accumulated salt. 

The principal tributary to Tulare ~ake Bed, the 

ICings River, is pecnliar because under both natural 

and regulated conditions it splits-part of the water 

flows south to Tulare Lake and part north to the San 

Joaquin River. During low and normal stages, most 

of the water flows to Tulare Lake Bed; during high 

stage much spills north to the San Joaquin. 

Two principal explanations have been advanced to 

account for the interior drainage of the southern San 

.Joaquin Vn,lley. One advocated by l\1endenhall and 

others (1916, p. 21), ,V. l\1. Davis (1933, p. 224), 

I-Ii nels ( 1952, p. 150), and many others explains the 

interior drainage as due to damming of the valley by 

the growth of the alluvial fans of the IGngs River 

from the east and Los Gatos Creek from the west. 

The other explanation suggests that Tulare Lake Bed 

:is the site of a structural downwarp and that active 

tectonic subsidence is the cause of the topographic depression (G.lL Davis and others, 1939, p. 29). 

The theory of damming by alluvial-fan growth implies that the formation of Tulare Lake occurred during the present cycle of deposition and presumes that 

through drainage was the rule before the .supposed 

damming. If this theory is valid, the sedimentary 

record should refiect these events. l\1aintenance of an 

alluvial dam across the axis of the valley would require continuing deposition of the fans. For example, the soils on the divide north of Tulare Lake Bed 

should be typical Recent alluvial-fan materials, the 

lacustrine soils of Tulare Lake Bed should be merely 

0 2 4 6 8 MILES 

EXPLANATION 

Anticline 

SlaowiflQ dirsction qf plunge qf azi.e 

--4oo_ 

Land-surface contours 

Interval to and 100 fest (contours 

omitted above 500 fut) 

---600._ 

Contours of top of Corcoran Clay 

Member of Tulare Formation 

(contours modified rifler Davie and others, 1959, pl.14)./ntsrval 50/BBt 

FrouuE 146.1.-Topography and structure of the Tulare Lake 

Bed area, San Joaquin Valley, Calif. 
D90 GEOLOGICAL SURVEY RESEAHCH 19 6 2 

a veneer, and the subsurface deposits of the lake bed 

should be alluvial deposits typical of the axis of the 

valley. 

The alternate theory is that Tulare Lake Bed is the 

surface expression of a structural depression flanking 

the J{ettleman Hills anticlinal structure. Subsurface 

evidence collected in recent years offers strong support for this theory, as discussed below. 

The surface soils in the area of the divide north of 

Tulare Lake are not typical alluvial-fan soils. Instead, a belt of clay "soils of the valley basins," indicative of deposition under conditions of poor surface drainage, extends northward from Tulare Lake 

Bed toward Fresno Slough (Retzer and others, 1946, 

fig. 3) and separates the IGngs River alluvial fan 

from that of Los Gatos Creek. Furthermore, the soils 

of the toe of the Los Gatos fan are classified by Hetzer 

and others as "soils of the old alluvial fans and valley 

plains," and not as Recent alluvial-fan deposits. These 

old fan soils belong to the Lethent series, which are 

characteristically heavy textured, calcareous, and show . 

considerable profile development. Taken together 

these features indicate that the Lethent soils are not 

accumulating under the present regime but are a relic 

of a previous cycle of deposition. Under present conditions of drainage, Los Gatos Creek deposits nearly 

all its load on the upper slope of the fan several mHes 

west of the valley axis. 

The lacustrine soils of Tulare Lake Bed are not a 

veneer over typical alluvial deposits of the valley axis 

as might be expected under the alluvial-dam theory. 

Instead, fine-grained deposits that are almost entirely 

silt and clay, indicating deposition in still water, extend to great depth. For example, well A (fig. 146.2) 

penetrated clayey deposits to a depth of 2,750 feet 

below sea level before encountering substantia] 

amounts of ·sand, and well B penetrated clayey material to 1,865 feet below sea level where it entered a 

sand 249 feet thick. Wells in the Tulare Lake Bed 

area remote from the Kings R.iver fan penetrate little or no sand in the upper several hundred feet; the 

lack of sand beds indicates that for a long period 

there was no through-flowing trunk stream along the 

valley axis. Moreover, the typical gray, blue, or black 

color of the deposits indicates deposition in a reducing environment, which would be expected in an area 

of poor drainage such as a lake or swampy area. 

The lithology and structure of the subsurface deposits as shown on figure 146.2 also support the structural theory. To the northeast, on the IGngs R.iver 

fan, the subsurface deposits consist of thin-bedded 

silty and sandy materials to a depth of more than 

1,200 feet, as shown by the electric log of well F. This 

sequence is interrupted by about 75 feet of diatomaceous lacustrine clay-the Corcoran Clay Member of 

the Tulare Formation-which has been traced in the 

subsurface throughout more than 5,000 square miles 

of the axial part of the San Joaquin Valley (Frink 

and J{ues, 1954, fig. 3; Davis and others, 1959, pl. 14.) 

The structural contours of figure 146.1, showing the 

configuration of the Corcoran Clay ~1ember, outline a 

structural depression whose axis passes through Tulare Lake Bed; the depression is elongated parallel 

to the trend of the J{ettleman Hills. The closure on 

the Corcoran is on the order of 300 feet, compared to 

a topographic closure of about 30 feet (fig. 146.1). 

Frink and l{ues (1954, fig. 2) show that the Corcoran 

attains its maximum thickness of more than 120 feet 

in the Tulare Lake area, suggesting that a topographic 

and structural low prevailed there before and during 

the widespread Corcoran lacustrine episode. This 

suggests that some of the relief on the Corcoran was 

clue to deposition on the sloping bed of a lake; however, the lithology of the deposits above and below 

the Corcoran in most of the San Joaquin Valley suggests that the gradient of the valley floor was little 

different than at present. Thus; the authors believe 

that the closure on the Corcoran is due chiefly to postdepositional structural warping. 

Sandy alluvial deposits of the Kings River fan, 

which are generally conformable with the Corcoran 

in the northeastern part of the section on figure 146.2, 

pinch out to the west or grade into thick-bedded, 

well-sorted sands as shown by the electric logs of wells 

C and D. The predominance of sand and the thick 

bedding suggest deposition as deltaic deposits along 

a lake shore, rather than as stream-channel deposits. 

The thick sand sequence penetrated by well C either 

pinches out or clips steeply toward 'vell B. l\1ost 

likely, the clayey deposits above -1,865 feet (sea-level 

datum) at well B are the fine-grained equivalents of 

the thick sands of well C. The absence of coarse alluvial deposits to depths of more than 2,000 feet beneath Tulare Lake Bed in the central part of the San 

Joaquin Valley indicates that through flow has not 

drained the valley during the interval represented by 

the upper 2,000 feet of deposits. The presence of 

clark silt and clay along the axis of the valley trough 

and thick probable beach sands to the east suggests 

that a lacustrine environment has been maintained for 

a long interval at the site of the present Tulare Lake 

Bed. l\1aintenance of such an environment requires 

continued relative subsidence of the area, otherwise 

the depression would have filled with sediments and 

through drainage would have been established. The 

present topography and drainage, therefore, are interpreted as resulting chiefly from the continued tectonic 
~ 

ARTICLE 146 D91 

sw 

A 

0 

It) 

,... 

N 

I 

2 

.l!! 

'iii 

0 

B 

Section consists almost 

entirely of silt and clay 

above and below Corcoran Clay Member 

(diatomaceous) 

Predominantly 

thin-bedded 

alluvial sand 

and silt 

NE 

200' 

100' 

-100' 

-200' 

-300' 

-400' 

-500' 

-600' 

-700' 

-800' 

-900' 

-1000' 

Q, 

Ill 

"0 

>-

Ill 

>-

Ill 

u 

Predominantly 

thick-bedded 

well-sorted 

lacustrine 

sands 

-1100' 

-1200' 

-1300' 

0 2 3 4 MILES -1400' 

-1500' 

:FJGunE 146.2.-Diagntmnuttic geologic section n.cross Tulare Lake Bed based on electric logs of water wells and oil-test wells~ 

Spontaneous-potential curve on left, resistivity curve on right at each well; scales not uniform. Alinement of section shown on 

figure 1.46.1. . 

subsidence of a synclinnJ structure paralleling the 

ICettle.nmn I-Iills anticlinal structure, rather than from 

damming of the drainage of the valley by alluvial-fan 

growth. 

REFERENCES 

.Dnvis, G. H., Greeu, .J. H., Olmsted, F. H., and Brown, D. W., 

195!), Ground-wuter conditions nnd storag·e. capacity in the 

Sun .Joaquin Vnlley, Cnlif.: U.S. Geol. Survey \Vnter-Supply 

Paper 1469. 

Davis, \V. M., 1933, The Jukes of California: California Jour. 

Mines and Geology, v. 29, nos. 1 and 2. 

654685 0-62--7 

!!"rink,· J. W., and Kues, H. A., 1954, Corcoran Clay-A Pleistocene lacustrine deposit in San Joaquin Valley, Calif.: Am. 

Assoc. Petroleum Geologists Bull., v. 38, no. 11, p. 2357-

237L ~~ Hinds, N. E. A., 1952, Evaluation of the California landscape: 

California Div. Mines Bull. 158. 

Mendenhall, "\V. C., Dole, R, B., and Stabler, Herman, 1916, ~ 

Grouud water in San Joaquin Valley, Calif.: U.S. Geol. 

Survey Water-Supply Paper 398. 

Retzer, J. r_.., Gardner, R. A., Koehler, L. F., and Cole, R. C., 1946, 

Soil survey of Kings County, Calif.: U.S. Dept. Agriculture 

Ser. 1938, no. 9, 102 p. 
D92 GEOLOGICAL SURVEY RESEARCH 1962 

147. TERTIARY SALT DOMES NEAR SAN PEDRO DE ATACAMA, CHILE 

By RoBERT J. DINGMAN, Santiago, Chile 

Work done in cooperation with the InstUnto de Investi,qaciones Geol6gicas, Santiago, Chile 

BOLIVIA 

\ \_ __ 0San Pedro 

rSdtar de J 

(rG~cama / 

J 

------- ,1/ ARGENTINA 

l. 

0 100 200 300 KILOMETERS 

FIGURE 147.1.-Index map of Chile showing location of 

Salar de Atacama. 

The Cerros de la Sal, in the west-central part of 

Antofagasta Province, Chile, form a narrow ridge 

approximately 45 miles long trending N. 20° E. along 

the western border of the Salar de Atacama (fig. 

147.1). 'fhe area is extremely arid and the village of 

San Pedro has an average annual rainfall of less than 

2 inches, although it is at an elevation of over 8,000 

feet. 

The area was mapped in August 1961 as a part of 

a ground-water investigation in the Salar de Atacama. The author was assisted part of the time by 

Ernesto Perez, geologist of the Instituto de Investigaciones Geol6gicas. Prof. S. E. Hollingworth and Roy 

Rutland, of the University of London, spent several 

days in the area and made many helpful suggestions 

concerning the structure of the area. No detailed 

geologic mapping had previously been done in this 

area. Various authors had mentioned the structure of 

the Cerros de la Sal, however, and had called them 

either salt domes or salt anticlines; Briiggen ( 1950) 

called them both. 

The oldest rocks exposed in the northern part of 

the basin containing the Salar de Atacama are continental deposits of the Salinas de Purilactis Formation of Jurassic ( ? ) age ( Briiggen, 1950). The formation is composed of approximately 1,800 feet of finegrained well-stratified basin-type deposits with a few 

intercalated beds of evaporites including salt, gypsum, and anhydrite. 

The Salinas de Purilactis Formation is overlain by 

approximately 15,000 feet of continental sediments of 

the Purilactis Formation of Cretaceous age (Briiggen, 

1950). The Purilactis Formation is subdivided into 

three members, as yet unnamed, that are herein referred to as the lower, middle, and upper members. 

The upper and lower members of the Purilactis Formation are relatively coarse-grained clastic sediments. 

EXPLANATION 

[EJ . . >- Eolian sand 0:: 

<( 

z 

G 0:: 

w 

I-

<( 

Piedmont deposits :::> 

0 

0 

Tuff 

Friable to welded >-

0:: 

<( 

I Tsp .1 Tsps I i= 

0::: 

w 

San Pedro Formation ITsps, salt beds 

Contact 

Dashed where approximately located 

.....__ u 

- D Fault 

Dashed where approximately 

located; U, upthrown side, 

D, down thrown side. Arrows 

show direction of horizontal movement 

Anticline 

Showing direction of plunge. 

Dashed where approximately 

located 

Syncline 

Slwwing direction 

of plunge 

+ 

Dome 

~ Strike and dip of beds 

~ 

Strike of vertical beds 

~ Salt mine 

Explanation for figure 147.2. 
I 

I 

I 

/ 

I I s6/ 

I 

I 

J 

ARTICLE 147 D93 

N 

Qp 

Qp 

Tsps 

500M 0 1 KILOMETER 

APPROXIMATE SCALE 

FIGURE 147.2.-Aerial photograph showing the geology of the Cerros de la Sal. 
D94 GEOLOGICAL SURVEY RESEARCH 19 6 2 

The middle member is composed of fine-grained redbed sediments and evaporite deposits typical of deposition in continental basins under arid conditions. 

The San Pedro Formation of early Tertiary age 

(Briiggen, 1950) is of continental origin and is composed of more than 6,900 feet of sediments and evaporite deposits. In the Cerros de la Sal it was possible to distinguish two types of deposit in the formation 

consisting predominantly of fine-grained clastic sediments and of salt beds (fig. 147.2). The few conglomerate beds in the sedimentary sequence contain wellrounded phenoclasts, many of which were derived from 

the conglomerates of the upper member of the Purilactis 

Formation. The salt beds of the San Pedro Formation 

are apparently the result of redeposition and· further 

concentration of the evaporite: salts from the Jurassic ( ~) and Cretaceous formations. 

The San Pedro Formation is overlain by rhyolitic 

tuffs of late Tertiary age, which are in turn overlain 

by Quaternary piedmont deposits. 

The Cerros de la Sal are formed by a series of 

domes and doubly plunging synclines and anticlines. 

They are bounded on the east by a well-exposed bor-

. der fault of unknown displacement, and there is evidence of a fault along the western border. The attitude of beds of well-stratified clastic sediments ranges 

from very steeply eli pping to slig4tly overturned on 

the flanks of the major structures .. In many localities 

the tops of the clastic beds can be determined by primary sedimentary features. In places the salt beds 

appear to be structureless on the surface, due to the 

masking effect of a mantle of salt up to 1 meter thick, 

which has resulted from leaching and subsequent redeposition on the surface following the infrequent 

rains. Primary structure in the salt beds may be observed in fresh exposures. The stratification of the 

salt beds is easily seen on aerial photographs (fig. 

147.2). . 

Faulting within the domes consists of minor vertical to high-angle normal faults. The boundary faults 

are nearly vertical with the downthrown blocks on 

the side away from the Cerros de la Sal. North of 

the area covered by figure 147.2 the upper Tertiary 

strata on the flanks of the Cerros are displaced by 

low-angle (14°). thrust faults trending north to N. 

30° E. 

Folding and doming of the San Pedro Formation 

began before the deposition of the upper Tertiary tuffs, 

and continued to the present. The tuffs were deposited as a blanket over the pre-existing topography. In 

some localities they are flatlying and rest with sharp 

unconformity on the San Pedro Formation. In other 

localities. they are conformable with the San Pedro 

w 

Cordillera de 

Domeyko 

E 

FIGURE 147.3.-Schematic section through the Cerros de la Sal 

showing how gravitational gliding could have produced local 

folding of the Cerros de la Sal (arrows indicate direction 

of movement). Tsp, San Pedro Formation. 

clastic sediments and have been tilted up to 90°, thus 

indicating continued development of the structures 

after the deposition of the tuffs. 

The author considers that ( 1) the preservation of 

bedding within the salt, (2) the parallelism of bedding between the clastic beds and the salt, and ( 3) the 

complete lack of inclusions or fragments of older rock 

within the salt beds are strong arguments against 

deep-seated diapiric folding being an important force 

in the formation of these structures. On the other 

hand, complex structures in Tertiary beds cannot be 

the product of regional tectonics in an area where the 

underlying Cretaceous strata are gently folded. Probably the Atacama basin subsided under the lower Tertiary sedimentary load, resulting in a slight tilting o.f 

the unconsolidated Tertiary sediments toward the center of the basin (fig. 147.3). Gravitational gliding 

toward the center of the basin, along beds of salt or 

gypsum in the San Pedro Formation, produced horizontal compression resulting in the upfolding of the 

Cerros de la Sal. This process of subsidence, gliding, 

and folding probably continued throughout the rest of 

the Tertiary and Quaternary and may still be active. 

There is no evidence in either the salt domes or in 

the regional geology to indicate marine deposition of 

the sediments related to these structures. The Cerros 

de la Sal may be unique in that they demonstrate 

well-exposed salt domes and anticlines in Tertiary continental sediments. 

SELECTED BIBLIOGRAPHY 

Bri.iggen, Juan, 1950, Fundamentos de la geologia de Chile: 

Santiago, Chile, Instituto Geografico Militar. 

Felsch, J., 1933, Informe preliminar sobre los reconocimientos 

geol6gicos de los yacimientos petroleros en la cordillera de 

la provincia de Antofagasta: Minas Petr61eo Bull., v. 2, 

no. 18, p. 411-422. 

Harrington, H. J., 1961, Geology of parts of Antofagasta and 

Atacama Provinces, northern Chile: Am. Assoc. Petroleum Geologists Bull., v. 45, no. 2. 

f 

,. 

.. 
',rJ 

•· 

( 

ARTICLE 148 D95 

148. ZINC OCCURRENCE IN THE SERPENT MOUND STRUCTURE OF SOUTHERN OHIO 

By ALLEN V. l-IEYL and ~1AURICE R. BRocK, Beltsville, ~1d . 

., Zinc minerals occur in dolomite shatter breccia 1 

exposed in the west-central part of the Serpent ~1ound 

"cryptovolcanic structure" (Bucher, 1936, p. 1060-

1064). The occurrence is particularly interesting because it i.s located in the central part of one of the 

most unusual and controversial structures in the central United States, and because zinc minerals have not 

been reported previously in southern Ohio (Ralph J. 

Bernhazen, State Geologist of Ohio, oral communication to I-Ieyl, 1961). The structure is 32 miles southwest of Chillicothe, Ohio, and is centered about 2 

miles east-northeast of Louden, a small town on Ohio 

Route 73 (fig. 148.1). 

The zinc minerals are present in several plaees in a 

low hill that lies east of a township road extending 

northward through the structure from Ohio Route 73. 

The hill. forms a low westward-trending prong 2 to 3 

acres in area that extends out from a large plateau of 

higher elevation that contains the core of the Serpent 

Mound structure. The parts of the hill where the 

zinc minerals were found are almost without soil and 

are covered with weathered fragments of gray dolomite shatter breccia. The dolomite lies within a unit 

mapped by Bucher (1936) as the Peebles and Greenfield Formations of ~1iddle and Late Silurian age. 

The shatter breccia is exposed in a small quarry at 

the east edge of the township road. Most of the 

angular breccia fragments are less than an inch across 

and have been rotated slightly or transported· during 

brecciation at most only a few feet. Shallow gullies 

expose less weathered but equally shattered rock. 

The shatter breccia undoubtedly was formed by the 

explosion which slutped the Serpent ~1ound structure. 

Bucher (1936, p. 1074-1081) suggested that this structure formed by an explosion at depth due to the sudden liberation of pent-up gases from an ineipient volcano ( cryptovolcano). ~1ore recently other geologists, 

. including Boon and Albritton ( 1936), Dietz ( 1961a, 

1961b), and Cohen and others (1961), proposed that 

the Serpent ~1ound structure was produced by meteor 

impact followed by explosion of the meteor at depth. 

The main evidence c.ited by them for meteoric impact 

is the absence of igneous material or related mineralization, and the presence of two pressure phenom~nashatter cones and the silica mineral coesite. Coesite 

1 Shn.tter breccln n.s used In this article refers to n breccia of one 

lithology, mot•e or less completely crushed, in which mnny small dis· 

locations between frngmcnts cnn be recognized. 

erystallizes only at high pressures (Chao and others, 

1960). 

After the shatter breccia was formed, recrystallization of dolomite grains at the interfaces of the fragments resulted in cementation of the breccia. The 

cemented rock was then broken a second time as shown 

by small shear zones and open fractures which locally 

cut the breccia. These shear zones and fractures contain most of the zinc. 

The zinc minerals consist of coarse- to mediumgrained sphalerite which is partly weathered to smithsonite and hydrozincite. Loose fragments of rock estimated to eontain 5 to 20 percent zinc and weighing 

as much as a few pounds are common at several places 

on the hill. Commonly the sphalerite crystals have 

red or reddish-brown cores surrounded by an orange 

zone and a pale-yellow rim. Most sphalerite is in the 

form of slightly fractured coarse grains with irregular boundaries against the buff to gray dolomite breccia whieh it has replaced (fig. 148.2). Sphalerite also 

fills, or partly fills, small vugs and open fractures. 

Gentle fracturing followed the deposition of sphalerite, and late-stage dolomite ·was introduced into the 

shear zones as an intimate mixture that forms the 

main gangue. Still later, hydrocarbon and more dolomite were deposited as veinlets that crosscut the sphalerite and gangue. 

The probable sequence of teetonic events and ore 

deposition is as follows: 

A. Initial structural events. 

1. Development of shatter-breccia during the main 

stages of formation of the Serpent Mound 

structure, probably under high pressures, with 

subsequent cementation. 

2. Localized shearing and fracturing of cemented 

shatter-breccia. 

B. Hypogene stages and associated tectonic events . 

1. Deposition of sphalerite as coarse replacement 

crystals in dolomite and as open-space fillings. 

2. Gentle fracturing of sphalerite and breccia. 

3. Limited replacement of sphalerite and breccia by 

dolomite, in part along fractures. 

4. Renewed shattering locally. 

5. Introduction of fine-grained hydrocarbon and 

associated dolomite in veinlets crosscutting the 

sphalerite and gangue. 

C. Supergene stages. 

1. Alteration of the sphalerite to smithsonite. 

2. Local further oxidation and minor deposition of 

hydrozincite. 
D96 

>-

l{ D 

Alluvium }! 0 

EIJ z Vl l ::;) 

Sandstone < 0 

t ~ 0::: cr: and shale a.. LLI 

~-~ Vi 14. 

-~ (,) z 

~ ~ Vl 0 Vl al 

cr: - ~ < 

Black shale u 

H { - rz < < 

~rj ik:~z 

Sandstone and :3<~ 

~~ . dolomite - LLI Vl 0 

~;;;; 

GEOLOGICAL SURVEY RESEARCH 19 6 2 

0 2 MILES 

EXPLANATION 

~ 

-~ ITlliiiiJ ;I 

'";! Dolomite ("/) 

...s 

~ z 

:s < 

~ Q: 

::;) 

Clay shale ...I 

Vi 

-~ '. ~ { - ;I~-~ ~ ;I 

..;i]~ Limestone 

Shale 

-

and 

limestone l 

~ 

~ 

> 

0 

0 

0:: 

0 

Fault 

DaBhed where injerred 

------

Contact 

-~ Zinc deposit 

FIGURE 148.1.-Geologic map of the Serpent Mound area showing location of the zinc occurrence. Geology after Bucher (1936, fig. 4). 
• 

ARTICLE 148 D97 

0 lcm 

FIGURE 148.2.-Photograph of a thin section showing slightly 

deformed sphalerite (darkest gray areas) in coarse replacement crystals in dolomite breccia. The very-light-gray fragments are host-rock dolomite. The mottled-gray areas are 

microbrecciated host rock cemented by post-sphalerite dolomite, which also locally replaced sphalerite (gray veinlets). 

The sphalerite is veined by a still later stage of hydrocarbon and dolomite (black and white veinlets). 

Much of the sphalerite is coated by smithsonite and 

hydrozincite. These supergene zinc minerals are fine 

grained, massive, and brown, buff, gray, and white. 

l\fost of the smithsonite, a direct-replacement product 

of sphalerite, is porous and spongy, but some is dense 

, and chertlike in appearance. Brown cellular boxworks 

of the typical "drybone" variety are fairly common. 

The boxworks are formed by smithsonite directly replacing sphalerite along cleavages and fractures, but 

some of the sphalerite between cleavages is dissolved 

and removed in. ground water without redeposition, 

leaving a smithsonite boxwork. Further oxidation of 

the boxwork replaced a little of the smithsonite with 

white hydrozincite. The abundance of sphalerite at 

the surface implies that supergene alteration of sphalerite is limited to shallow depths. 

The brief reconnaissance study indicates that the 

zinc occurrences are small, but they are distributed 

over much of the 2 or 3 acres of exposed outcrop. The 

zinc may not be abundant enough to form a commercial-grade deposit, but it should be a useful starting 

point to search for better deposits in this unprospected 

part of the Mid west. 

Geologically important are the facts that: (1) the 

zinc is in all respects epigenetic to the wallrocks and 

host fractures; the coarse crystal habit and gentle 

shattering of the sphalerite indicate it was deposited 

after the Serpent Mound structure had ceased major 

movement and after the breccia was cemented; (2) the 

ore solutions used previously formed fractures as channelways; (3) the sphalerite is younger than the youngest strata involved in the structure and thus is postMississippian in age; and (4) sphalerite deposition 

was followed by two later periods of minor shattering 

and dolomite deposition. 

The several stages of fracturing and mineralization 

of the sphalerite suggest that the enclosing Serpent 

Mound structure also developed in several related 

stages over a considerable period of geologic time. 

Such a complex history is incompatible with the 

hypothesis that the structure was formed by meteoric 

impact and explosion of an imbedded meteor. The 

multistage structural history and the occurrence of 

zinc is compatible with the hypothesis that later stages 

of reeurring deep-seated volcanic explosions (Bueher, 

1936) were accompanied and followed by mineralization. 

REFERENCES 

Boon, J. D., and Albritton, C. C., 1936, Meteoric impact craters and their possible relationship to "cryptovolcanic 

structures": Field and Lab., v. 5, p. 1-9. 

Bucher, W. H., 1936, Cryptovolcanic structures in the United 

States: Internat. Geol. Cong., 16th, Washington, 1933, 

Rept., v. 2, p. 1055-1084. 

Chao, E. C. T., Shoemaker, E. M .• and Madsen, B. M., 1960, 

First natural occurrence of coesite : Science, v. 132, no. 

3421, p. 220-222. 

Cohen, A. J., Bunch, T. E., and Reid, A. M., 1961, Coesite discoveries establish cryptovolcanoes as fossil meteorite craters: Science, v. 134, no. 3490, p. 1624-1625. 

Dietz, R. S., 1961a, Astroblemes: Sci. Am., v. 205, no. 2, p. 

50-58. 

-- 1961b, Vredefort ring structure: meteoric impact 

scar?: . Jour. Geology, v. 69, no. 5, p. 494-516. 
D98 GEOLOGICAL SURVEY RESEARCH 19 6 2 

GEOPHYSICS 

149. THERMOLUMINESCENCE INVESTIGATIONS AT METEOR CRATER, ARIZONA 

By C. H. RoAcH, G. R. JoHNSON, J. G. ~fcGRATH, and T. S. STERRETT, Denver, Colo. 

Wm·k done in cooperation with the National Aeronautics ancl Space Administrat.ion 

Preliminary study of rocks from the vicinity of 

Meteor Crater that have been shocked by hypervelocity 

impact in the laboratory indicates that the thermoluminescence of some of these rocks is affected by 

shock. Field studies at Meteor Crater, Ariz., have 

been undertaken to determine whether the thermoluminescence of the rocks was affected by the shock 

propagated by impact of the meteorite. 

Two characteristics of thermoluminescence of rocks 

shocked under laboratory conditions vary with the 

strength of the shock: (a) the total amount of thermoluminescence (area under the . glow ·curve) decreases 

systematically with distance from the shock origin 

and, therefore, with decreasing peak shock pressure; 

and (b) in some rock types strong shock causes the 

low-temperature peak to have a greater amplitude 

than the high-temperature peak (Roach and others, 

1961). These two characteristics of thermoluminescence are being used to help reconstruct the history 

· of shock propagation at Meteor Crater. 

GEOLOGY OF METEOR CRATER 

The geology of Meteor Crater has been described 

by E. M. Shoemaker ( 1960) as follows: The crater 

lies in the southern part of the Colorado Plateau in 

north-central Arizona. Near the crater, the surface of 

the Plateau has a very low relief and is underlain by 

well-exposed, nearly flat lying beds of Permian and 

Triassic age. The crater lies near the crest or upper 

axis of a gentle monoclinal fold, a type of structure, 

characteristic of this region. The strata are broken 

by widely spaced northwest-trending normal faults, 

generally many miles in length but with only a few 

tens of feet to about a hundred feet displacement. 

Two sets of regional vertical joints are present near 

the crater; one set is subparallel to the normal faults 

and the other set is at right angles to the first set. 

Meteor Crater is a bmYl-shaped depression 600 feet 

deep and about three-fourths of a mile in diameter encompassed by a ridge or rim that rises 100 to 200 feet 

above the surrounding plain. Rocks exposed in the 

crater, in ascending stratigraphic order, are: the upp~r 

part of the Coconino Sandstone (Permian) , about 

9 feet of Toroweap Formation (Permian), 270 feet of 

Kaibab Limestone (Permian), and about 40 feet of 

reddish-bro,vn sandstone and siltstone of the Wupatki 

Member of the Moenkopi Formation (Triassic). 

Moenkopi and Kaibab strata are turned up at moderate to steep angles in the wall of the crater and are 

locally overturned in the rim. The bedrock in the ri~ 

is overlain by a complex sequence of Pleistocene debris. 

Original bedrock stratigraphy is preserved, inverted, 

in the debris units. Pleistocene and Recent alluvium 

rests uncomfortably on all of the debris units as well 

as on bedrock. 

The structural and geologic characteristics of Meteor 

Crater are fully explained by impact of a large meteorite in late Pleistocene time. The meteorite, with a 

density of about 7.85 g per. cc, has been estimated by 

Shoemaker (1960) to have had an impact velocity of 

about 15 km per sec, a diameter of about 80 feet, and 

a total kinetic energy of 1.4 to 1.7 megatons TNT 

equivalent. 

THERMOLUMINESCENCE OF BEDS 

The thermoluminescence of all stratigraphic units 

exposed in Meteor Crater and of all units in the 

Q.uaternary debris is being studied; to date, however, 

emphasis has been focused on three easily identified 

individual beds or narrow stratigraphic intervals exposed in the rim of the crater. In order of depth 

·below the original pre-impact surface these are: (a) a 

reddish-brown calcareous siltstone bed of the Moenkopi Formation about 25 feet below the pre-impact 

land surface; (b) the "lower massive sandstone" 

(McKee, 1954) of the ~1oenkopi Formation, about 35 

feet below the pre-impact surface; and (c) a marker 

bed, the "geode bed," of the alpha member (Cadigan, 

1957) of the l{aibab Limestone, about 50 feet below 

the pre-impact surface. Samples from each of these 

beds were taken at several places around the rim of the 

crater (figs. 149.1, 149.2, 149.3). 

Both the total thermoluminescence and the relative 

height of the low-temperature peak suggest that all 

samples of the siltstone bed of the ~1oenkopi Formation have been subjected to shock (fig. 149~1). Varia-

\ .• 

:~./ 

..... 

... 
t 

•• 

~ 

\. 

~\ :-

~· 

_ .. 

·•· 

... 

ARTICLE 149 D99 

1,882 sq in. EXPLANATION 

N 

300 in. 

0 

Db :::2.35 

L-634 0 

695 sq in. 

174 in. 

0 

Db:::2.30 

• L;-763 

.... 

Quaternary deposits and 

allogenic breccia 

Moenkopi Formation 

(Triassic) 

UNCONFORMITY 

D 

Kaibab, Coconino, and 

Toroweap Formations 

(Permian) 

0 METEOR Authigenic breccia 

Occurs mostly __ along faults 

CRATER 

1000 

----- Contact 

~ Normal or nearly vertical faults 

Thrust ~ fault 

Barbs on upper plate 

L-634 . . 

Sample locality 

Total area 

-

under glow curve 

Adjusted for amplification scale 

~ Height of peak 1 minus height 

of .peak 2 

Adjusted for amplification scale 

Db =Dry-bulk density ( g percc) 

FIGURE 149.1.-Thermoluminescence characteristics of siltstone of the Moenkopi Formation in the rim of Meteor Crater. 

tion of both of these characteristics suggests that the 

strength of the shock was greatest in samples from the 

south ha,lf of the crater r.im. Three closely spaced 

samples were taken where the siltstone ped is exposed 

in an overturned fold on the east r.im of the crater (fig. 

149.4). The glow curves suggest that the overturned 

and axial regions of the fold were subjected to stronger 

shock than the normal limb. Variation of the drybulk density of the siltstone correlates with variation 

in the thermoluminescence characteristics (figs. 149.1, 

149.4:). A permanent increase of bulk density was 

probably produced by shock. 

Thermoluminescence characteristics of samples of 

the lower massive sandstone of the Moenkopi Formation are less distinctively of the shocked type than are 

those of the overlying siltstone bed (149.2). All samples except L-722 from the northeast corner of the 

crater, however, exhibit glow curves of the type produced by shock (positive value of peak 1 minus peak 

·2). Sample L-722 is from near a prominent tear fault 

associated with an overturned flap of the east wall of 

the crater, and it is possibl~ that the local stress distribution during the formation of this tear fault is 

the cause of the anomaly in thermoluminescence. The 

strength of the shock in the ]ower massive sandstone 

appears to have been greatest in the southeast quadrant of the crater. As in the siltstone there is a general tendency for samples having the greatest amount 
DlOO 

140 sq in. 

65 sq 

3,435 sq in. 

EJ . 

. Quaternary deposits and 

allogenic breccia 

Moenkopi Formation 

(Triassic) 

UNCONFORMITY 

D 

Kaibab, Coconino, and 

Toroweap Formations 

(Permian) 

GEOLOGICAL SURVEY RE.SEAR•CH 19 6 2 

246 sq in. 45 in. 

0 0 • 

Db=2.01 

L-633 

METEOR 

CRATER 

1000 

0 62 sq in. 

L-722 -1.5 in. 0 

Db=2.06 

N 

0

ill•••••••• 2,565 sq in. 

1,875 sq in. 

EXPLANATION 

Authigenic 

~ breccia 

Occurs mostly along faults 

~ 

Contact 

~ Normal or nearly vertical faults 

Thrust fault 

Barbs on upper plate 

L-~33 

Sample locality 

Total area 

-

under glow curve 

Adjusted for amplification scale 

~ Height of peak 1 minus heiaht 

of peak 2 

Adjusted for amplific6tion scale 

Db =Dry-bulk density (g percc) 

FIGURE 149.2.-Thermoluminescence characteristics of the lower massive sandstone of t·ne Moenkopi Formation in the rim 

of Meteor Crater. 

.... ....... 

.... 
~ 

~ 

~ 

.,;::, 

.. 

.. 

... 

L-716 

Db=2.34 

wiOO 

0 

z 

w 

~ I' 

z , ; 

i I :I 

____ , .J I 0 

::E I 0:: ,,.... w 

J: .'.t 1- o, 100 

TEMPERATURE, IN •c 

-"" / \ I_, \ 

r-" 

I 

.I 

I 0 

100 

TEMPERATURE, IN •c 

... 

~ 

w'oo~---------------( 

CJ 

z 

w 

~ z 

j 

:I 

.J 

0 

::E 

0:: 

1&.1 

~ oL-~----r---~--~ t I ~ 

TEMPERATURE, IN •c 

ARTICLE 149 

100~--------~--~· 

w 

0 

z 

w 

~ z 

i 

:I 

.J 

0 

::E 

0:: 

w 

./ \ 

~ 0~-1~00----r---.---~~ 

TEMPERATURE. IN •c 

DlOl 

N 

100 ~ 

... 

METEOR 

CRATER 

1000 

EXPLANATION 

[I] . 

. 

. Quaternary deposits and 

allogenic breccia 

Moenkopi Formation 

(Triassic) 

UNCONFORMITY 

D 

Kaibab, Coconino, and 

Toroweap Formations 

(Permian) 

TEMPERATURE. IN •c 

• . 

/I 0

t too ~ TEMPERATURE. IN •c 

0·' 

Authigenic breccia 

Occurs mostly along faults 

----

Contact 

~ Normal or nearly vertical faults 

Thrust 

~ fault 

Barbs on upper plate 

100 

TEMPERATURE, IN •c 

L-704 

• Sample locality 

Db= Dry-bulk density (g per cc) 

f 

Room temperature 

Scale factors _, _____ 1:10 

-------- 1:30 

---- 1:100 

1:300 

FIGURE 149.3.-Thermoluminescence characteristics of the geode bed of the alpha member of the Kaibab Limestone in the rim 

of Meteor Crater. 
D102 GEOLOGICAL SURVEY RESEAHCH 19 6 2 

of thermoluminescence to have the highest dry-bulk 

density' indicating that the lower massive sandstone 

b~d was exposed ~o greater permanent compression in 

the southeast quadrant of the crater rim than elsewhere. · 

Glow curves of samples from the geode bed of the 

Kaibab Limestone exhibit a complex pattern of variation with respect to position along the crater rim (fig. 

149.3). Only sample L-654, from the southeast corner 

of the crater rim, yielded a glow curve indicative of 

strong shock (positive value of peak 1 minus peak 2). 

No correlation is apparent between the thermoluminescence and dry-bulk density of samples of the geode 

bed as exists for the siltstones and sandstone beds in 

the overlying Moenkopi Formation. The geode bed 

contains numerous vugs, however; this feature makes 

it difficult to obtain a representative bulk-density measurement from the small core specimens that are normally used for bulk-density measurements. A larger 

number of bulk-density measurements will be required 

to determine a representative value for a significant 

volume of rock at any sampling locality. 

Comparison of the thermoluminescence of samples 

of the three marker beds taken from a measured section on the north rim of the crater .with those from a 

corresponding section on the southeast rim (figs. 149 .3, 

149.5) shows that rocks exposed in the southeast quadrant of the crater appear to have received the strongest 

L-760 

N L-760 

-850sq in. 

~ 230 in. 

Db=2.40 

L-761 

••••• 1.497 sq in. 

Lower massive ~ 350 in. 

sandstone of Db=2.44 

Moenkopi 

Formation 

L-762 L-762 

••••• 1.821 sq in. 

~480in. 

Db=2.48 

EXPLANATION 

Siltstone 

of Moenkopi 

Formation 

0 10 FEET 

APPROXIMATE SCALE 

Total area under 

-

glow curve 

Adjusted for amplification scale 

~ Height of peak 1 minus height 

of peak 2 

Adjusted for amplification scale 

Db= Dry-bulk density ( g per cc) 

"<.__ 

Strike and dip of beds 

'tx_ 

Strike and dip of overturned beds 

FIGURE 149.4.-Diagrammatic sketch of an overturned fold on 

the east rim of Meteor Crater. 

c 

~ 

E "'

~ 

·a. 

~ c 

CD 

0 

:::E 

CD 

c 

0 

i 

E 

::J 

..c 

"' ..c 

'iii 

::.:: 

NORTH RIM 

0 

- 1,882 sq in. 

~ 300 in. 

0 

Siltstone 

0 

SOUTH RIM 

0 

=780in. 

0 

0 

3,066 sq in. 

r 

246 sq in. 

45 in. 

- 1,879 sq in. 

~570in. 

0 0 

lower massive sandstone 

0 0 

. - 1,766 sq in. 

-140 in.~ 

.. 1,166 sq in. 

~40 in. 

0 

0 

• 228 sq in. 

-8 in.~ 

0 

0 

Geode bed 

0 

-15 in. r 381 sq in . 

0 

Sandstone marker 

Total area under 

-

glow curve Height of peak ~ 1 minus height 

Adjusted for amplification scale of peak 2 

Adjusted for amplification scale 

FIGURE 149.5.:--Thermoluminescence of marker beds in the 

rim of Meteor Crater. 

shock, and rocks along the northern part of the crater 

appear to have been shocked least. At greater depths 

rocks also seem to have been more strongly shocked 

in the southeast part of the crater than elsewhere. 

Glow curves obtained from samples L-710 and 

L-724 from the geode marker bed differ from all other 

glow curves obtained from Meteor Crater to date in 

that they have only one peak-the high-temperature 

peak. The absence of a low-temperature peak in glow 

curves of these samples cannot be completely explained 

at this time. Carbonate samples that normally have 

two-peak glow curves will yield a glow curve having 

only a high-temperature peak if they are subjected to 

high temperature (200°C to 250°C), or are recrystallized. Further study is planned to determine the conditions which might account for the somewhat unique 

glow curves of these two samples. 

CONCLUSIONS 

Preliminary study suggests that thermoluminescence 

may be used as a guide to the stress history of rocks 

exposed in the rim of Meteor Crater, Ariz. The areal 

and stratigraphic variations of shock strength are 

probably recorded by the changes in the thermoluminescence in rocks exposed in the rim. of the crater. 

Variations in bulk density are correlated with the 

variations in thermoluminescence in the siltstone and 

"lower massive sandstone", of the Moenkopi Formation. 

,-· 

.... 
~· 

ARTICLE 150 Dl03 

The present study suggests that the point of impact 

and upper part of the path of penetration of the 

meteorite may have lain southeast of the center of the 

crater. As the crater rim is probably roughly centered 

about the center of gravity of the total energy delivered during penetration of the meteorite (Shoemaker, 

1960, p: 431), the results of this study suggest that the 

meteorite was moving from southeast to northwest. 

Additional study is needed, however, before definite 

conclusions can be drawn. 

The present study also suggests that thermoluminescence techniques might be useful in the study of 

cryptovolcanic structures (Bucher, 1936), which are 

structures thought by some to have originated by impact mechanism rather than by volcanic processes 

(Shoemaker and Eggleton, 1961). Thermoluminescence investigations of some of these "possible impact" 

structures are now underway. 

REFERENCES 

Bucher, W. H., 1936, Cryptovolcanic structures in the United 

States: Internat. Geol. Cong., 16th, Washington, D.C., 

1933; Rept., v. 2, p. 1055-1084. 

Cadigan, R. A., 1957, Lithologic studies: U.S. Atomic Energy 

Comm. TEl Rept. 700. · 

McKee, E. D., 1954, Stratigraphy and history of the Moenkopi 

Formation of Triassic age : Geol. Soc. America Mem. 61, 

133 p. 

Roach, C. H., Johnson, G. R., McGrath, J. G., and Spence, F. H., 

1961, Effects of impact on thermoluminescence of Yule 

marble: Art. 272 in U.S. Geol. Survey Prof. Paper 424-C, 

p. C342-C346; also in U.S. Geol. Survey Astrogeologic Studies Semiann. Prog. Rept. to NASA, Aug. 25, 1960 to Feb. 25, 

1961, p. 82-90. 

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. 

Shoemaker, E. M., and Eggleton; R. E., 1961, Terrestrial fea-

.tures of im.pact origin: Geophysical Laboratory-Lawrence Radiation Laboratory Cratering Symposium Proc., 

UCRrr-.:6438, pt. I, p. A1-A27. 

150. ELECTRICAL AND MAGNETIC PROPERTIES OF A REPLACEMENT-TYPE MAGNETITE DEPOSIT IN SAN 

BERNARDINO COUNTY, CALIFORNIA 

By CHARiEs J. ZABLOCKI, Denver, Colo. 

An electrical-properties survey was made of the 

rocks penetrated by 5 exploration drill holes about 

20 miles south of Daggett, San Bernardino County, 

Calif. The work was done as part of a program of 

the ·u.S. Geological Survey to determine the electrical 

properties of rocks in selected mineralized areas. The 

holes were drilled by the Columbia Iron Mining Co.1 

to evaluate a replacement-type magnetite deposit associated with siliceous metasedimentary and metavolcanic rocks, ]jmestone, marble, and monzonite. 

Resistivity, induced-polarization, and magneticsusceptibility measurements were made in 5 drill holes 

which ranged from 250 feet to 2,800 feet in depth. 

Siliceous metasedimentary and metavolcanic rocks 

that overlie the magnetite-bearing zones are brecciated 

and fractured in many places. Resistivities measured 

in these sections are relatively low, ranging from 100 

to 500 ohm-meters. Resistivities of more than 2,000 

ohm-meters were measured in fine-grained nonporous 

limestone, skarn, and slightly fractured marble and 

limestone. In some of these rocks, disseminated pyrite 

1 The cooperation of the Columbia Iron Mining Co., particularly of 

Dr. Rodger H. Chapman, is gratefully acknowledged. 

is abundant, but only where pyrite was reported as 

being massive is the resistivity substantially reduced. 

In the magnetite-bearing rocks, the resistivities are 

less than 1 ohm-meter where the magnetite exceeds 

about 20 percent by volume. This very low resistivity 

is due to solid conduction through connected grains of 

magnetite. The resistivity of a part of the footwall 

monzonite, which underlies a major zone of mineralized rock, is about 1,500 ohm-meters. 

The only significant induced polarization response 

( 3 percent) was measured in metasedimentary rocks 

containing about 4 percent disseminated pyrite. Measurements in the ore zones eould not be made because 

of the high conductivity of the ore. 

~{agnetic-susceptibility logs indicate an average susceptibility of 0.18 cgs unit for the magnetite deposit. 

Magnetic-susceptibility logs in monzonite indicate a 

value of about 0.01 cgs unit, which corresponds to 

about 5 percent magnetite by volume. 

Parts of resistivity and magnetic-susceptibility logs 

in magnetite-bearing siliceous metasedimentary rocks 

are shown in figure 150.1. A short-normal resistivity 

array with a 4-inch electrode spacing was used in order 
D104 GEOLOGICAL SURVEY RESEARCH 1 9 6 2 

l;j 

LLI 

~ 

~ 

£ 

li: 

LLI 

MAGNETIC 

SUSCEPTIBILITY 

RESISTIVITY (cgs units) MAGNETITE 

(ohm-meters) 0 0.03 0.06 o.og _ (volume percent) 

0 100 300 1100 2700 0 0.06 0.12 0.18··· 0 10 20 30 

I I I 1'-.... ~ 

~ ··-·::~ 

~ 

. ., .... 

-====--... 

~ 

;::::==-

0 

2200~~~~~~ ~ 

r-----...._ 

r< 

~ 

1\.. 

~ 

I I I 

FIGURE 150.1.-Parts -of geophysical logs from a diamond-drill 

hole in magnetite-bearing siliceous metasedimentary rocks, 

San Bernadino County, Calif. Resistivity. is departure corrected; magnetite content estimated visually. .. 

to resolve the resistivities of thin layers or zones. The 

maximum resistivity that could be measured was limited by this relatively small electrode spacing as well 

as by the borehole diameter and resistivity of the borehole fluid. For these particular boreholes, the maximum resistivity that could be measured was about 

3,000 ohm-meters. Therefore, where an apparent resistivity of about 3,000 ohm-meters was measured, the 

rocks probably have a true resistivity considerably 

greater. Laboratory measurements made on 8 representative samples ranged from 3,500 ohm-meters to 

15,000 ohm-meters. This is in accordance with their 

very low intergranular porosity (less than 1 percent)~ 

The resistivity log in figure 150.1 indicates extremely 

low resistivities for 2 zones at 2,030 and 2,045 feet. 

The low resistivities are due to solid conduction 

through connected grains of magnetite. Highly fractured zones are indicated on the log by intervals of 

low resistivity at 2,230 and 2,315 feet. 

The magnetic-susceptibility log shows good correlation with the assay log, in which the magnetite was 

estimated visually. Better correlation would be expected if a chemical assay over closer intervals had 

been available. The example demonstrates that this 

type of logging tool may be used to detect thin seams 

of magnetite as well as small variations in the oregrade zones. Also, with a magnetic susceptibility log, 

assay samples could be chosen so that relatively uniform intervals would be included in each sample 

length instead of choosing them arbitrarily. 

The table below shows the average values of resistivity and magnetic susceptibility for the rock types 

penetrated. 

Summary of average values of resistivit'!l and magnetic susceptibility for the rock types penetrated, San Bernardino County, 

Calif. 

Rock type 

Siliceous meta.sedimentary and volcanic (highly fractured) _________________ _ 

Fine-grained limestone and skarn (un- fractured)_. ______________________ _ 

Marble-limestone (unfractured) ----- __ _ Monzonite (fractured) _________ ----- __ 

Mineralized zones ( < 20 percent FeaO.) _ Mineralized zones ( > 20 percent FeaO.) _ 

Average 

resi8ti~itu, · in ohm-meters 

Magnetic 

susceptibility 

in ega units 

100-500 Nil 

>2, 500 Nil 

>2, 500 Nil 

1,500 0. 01 

500-1,500· .002-. 04 

<1 .• 04-. 30 

It is interesting to note that, in general, 20 percent 

magnetite by volume is required to render the rock 

conductive. In contrast, measurements made on some 

magnetite-bearing rocks in the western part of the 

Gogebic iron range, Wisconsin (Zablocki and Keller, 

1957) showed that solid cond~ction occurred where 

the magnetite content was as l~ttle as 6 percent by 

volume. The difference is due to the mode of occurrence of the magnetite. In the replacement deposit, 

the magnetite occurs as medium to coarse grains and 

crystals disseminated throughout the host. rock. In 

the Gogebic range, the magnetite occurs in thin beds 

and anastomosing bands which render the rock conductive over a large volume because of the continuity 

through the grains. 

REFERENCE 

Zablocki, C. J., and Keller, G. V., 1957, Borehole geophysical 

logging methods in the Lake Superior district, in Drilling 

symposium, 7th annual, exploration drilling: Minneapolis, Minnesota Univ. Center for Continuation Study, p. 

15-24. 

.. l 

,., 
ARTICLE 151 D105 

151. DETERMINATION OF THE MAGNETIC POLARITY OF ROCK SAMPLES IN THE FIELD 

• By RICHARD R. DoELL and ALLAN Cox, Menlo Park, Calif. 

) 

The directions of remanent magnetization of most 

rocks of post-Eocene age may be divided into two 

groups: a normal group, in. which the remanentmagnetization vectors have roughly the same direction as the present geomagnetic field at the sampling 

locality; and a reversed group, in which the remanentmagnetization vectors are directed nearly opposite to 

the present geomagnetic field. At all localities over 

the earth, the present geomagnetic field is clo~e to 

that which would be produced by a magnetic dipole 

(that is, a short bar magnet) at the center of the 

earth with its north 'magnetic pole directed toward 

the so1.dl1- geographic pole. The resulting magnetic 

field at the earth's surface is directed toward the 

north geographic pole and is inclined to the horizontal at different angles appropriate to the geographic 

latitude of the sampling area. The appropriate angle 

of the inclination, I, is given by: 

I = arctan (2 tan 8) 

where 8 is the geographic latitude, assigned a positive 

value in the northern hemisphere and a negative · 

value south of the equator. Correspondingly, the inclination is positive in the northern hemisphere, indicating inclinations below the horizontal, and negative 

in· the southern hemisphere, specifying inclinations 

above the horizontal. Figure 151.1A shows this relationship graphically and also, therefore, indicates the 

average orientation at different latitudes for rocks of 

the normal group. Figure 151.1B shows the relation 

for rocks of the reversed group. 

The occurrence and distribution of reversely magnetized rocks have been interpreted as evidence that 

the polarity of the earth's magnetic field has reversed 

20 or more times since the Eocene. The best stratigraphic evidence now available indicates that the two 

most recent reversals occurred in the Pleistocene 

(Matuyama, 1929; Hospers, 1954; Rutten, 1960; Doell 

n.J1d Cox, 1961a). Transitions from one polarity to 

the other are observed to occur within very narrow 

stratigraphic intervals, and since all geomagnetic-field 

theories require that the transitions be contemporaneous over the entire earth, these horizons may prove 

very useful for stratigraphic correlation. 

However, it cannot be assumed that all reversely 

magnetized rocks were formed when the geomagnetic 

field was reversed, because at least one of the ferromagnetic minerals found in rocks is known to be self 

GEOGRAPHIC 

NORTH 

A. NORMAL 

GEOMAGNETIC FIELD 

GEOGRAPHIC 

NORTH 

B. REVERSED 

GEOMAGNETIC FIELD 

FIGURE 151.1.-Directions of the geomagnetic field at various 

latitudes expected for (A) a normal geomagnetic field (present configuration) and (B) a r~versed geomagnetic field. 

reversing (Uyeda, 1958). This mineral, a solid solution of ilmenite and hematite, acquires a magnetization exactly opposing the applied geomagnetic field 

when it is cooled from above its Curie temperature 

in the laboratory·. Moreover, the possibility of self 

reversals that cannot be reproduced in the laboratory 

has been suggested (Neel, 1951; Verhoogen, 1956, 

1962). Detailed laboratory analysis for the presence 

of reproducible self-reversing properties is always 

desirable, but field study of the stratigraphic distribution of normally and reversely magnetized rocks 

throughout geologic units may provide even more 

critical evidence concerning the presence or absence of 

self reversals. For example, rare occurrences of both 

normal and reversed magnetizations within the same 

lava flow or small intrusion (Asami, 1956; Strangway, 1961) clearly indicate self reversal whether or 

not this property can be reproduced in the laboratory. 

However, most of the field evidence now available 

indicates that natural self reversals are rare, since it 

is much more common to find the same magnetic polarity in rocks with vastly different mineralogies which 

were magnetized at the same time. For example, 

many lava flows and the sediments baked by them 

have the same polarity, whereas none have been found 

with opposing polarities (Brunhes, 1906; Roche, 1953; 

Einarsson and Sigurgeirsson, 1955; Wilson, 1961). 

Similarly, normal and reversed zones usually follow 

time horizons in thick. stratigraphic sequences but 
D106 GEOLOGICAL SURVEY RESEARCH 19 6 2 

transgress petrologic horizons, indicatfng that self reversaJs are probably absent. Preliminary measurements in the field are therefore valuable as a guide 

for more detailed sampling and laboratory study, and 

where consistency of polarity can be established 

among samples of different mineralogy from the same 

time horizon, such field measurements should suffice 

for purposes of mapping and correlation. 

This article describes a technique for using a declination gradiometer and a small portable magnetometer to measure the magnetic polarity of oriented hand 

samples. Although the sensitivity of the magnetometer described is not great enough to measure most 

sediments, it is quite sufficient to measure almost all 

igneous rocks and some of the more strongly magnetized sediments. 

In making such determinations in the field, it is important to recognize and avoid rocks that have been 

struck by lightning. The strong magnetic field of one 

lightning bolt may realine the remanent magnetization of rocks in an area 5 to 25 meters in diameter, 

completely masking the original magnetic polarity 

(Cox, 1961; Graham, 1961). A simple way to determine where lightning has struck is to measure the local 

magnetic anomalies adjacent to the outcrop in question, since the strong magnetic fields associated with 

lightning bolts. induce intense remanent magnetizations 

which in turn cause large anomalies within a few 

tens of centimeters from the outcrop. Although such 

gradients may be readily determined with a geologist's 

compass using a distant point as a referenGe, we have 

found a simple declination gradiometer much easier 

to use. 

The gradiometer consists of two small oil-damped 

moving-card-type magnetic compasses mounted in 

simple gimbals at opposite ends of a rigid rod about 

half a meter in length (fig. 151.2). The compasses 

are arranged with their index marks parallel so that 

a difference in their readings, divided by their separation, yields the declination gradient in degrees per 

meter. With at least one of the compasses held immediately adjacent to. the outcrop, local declination 

FIGURE 151.2.-The declination gradiometer. 

anomalies are quickly located. Gradients of 20° to 60° 

"per meter are quite common along ridges in areas of 

h~gh lightning incidence. For most lava flows, the 

absence of gradients greater than 5° per meter over 

an outcrop area greater than 2 meters in length indicates that samples near the center of the outcrop will 

be free from the effects of lightning. The exact value 

of the gradient to be used as a criterion for the absence of lightning effects depends upon the amount 

and type of ferromagnetic minerals present in the 

rock. 

For measuring the magnetic polarity of igneous 

rock~ by the techniqiles described here, any magnetometer having a directionally sensitive detector that can 

be alined perpendicular to the earth's magnetic field 

may be used. The magnetometer should be capable of 

measudng fields as· small as 25 gammas (25 X 10-5 

oersteds) for typical basaltic extrusive rocks, 5 gammas for rhyolites, and about 1 gamma for acidic intrusive rocks. Our instrument is of the saturablecore or fluxgate type and is a modification of a design 

by Serson and Hannaford (1956). ·The detector head 

of this magnetometer is 1.5 em in diameter by 10 em 

in length and is mounted on a small aluminum tripod 

with a universal head. It is connected by an electrical 

cable (fig. 151.3) to a battery-powered electronics unit 

measuring 16 em X 16 em X 15 em and weighing 

about 2 kilograms. The detector is sensitive to the 

magnetic-field component exactly parallel to its axis 

but does not respond to magnetic-field components 

perpendicular to the axis. 

Before determining the polarity of an oriented rock 

specimen, the sensitivity of the instrument must be 

properly adjusted and the detector axis alined exactly 

perpendicular to the local geomagnetic field. This 

may be done by placing the detector in a horizontal 

and roughly east-west orientation and, with the sensitivity control initially set to a low value, rotating 

the detector about a vertical axis until the indicating 

meter reads near the center zero. The sensitivity is 

then increased, generally causing the meter to deflect 

away from the center position, and the detector is carefully reoriented to again bring the meter to a zero 

center reading. A test signal, equivalent to a 15-

gamma change in the magnetic field along the detector 

axis, is applied after each increase in sensitivity, and 

the above steps are repeated until the meter reads 

near the zero center and the test signal indicates a 

sensitivity sufficient to measure the rocks being studied. 

When adjusted in this manner with the detector 

axis exactly perpendicular to the local geomagnetic 

field, small magnetic fields directed parallel to the 

detector axis can be measured; moreover, the detector 
~I 

ARTICLE 151 D107 

IN SITU 

NORTH AND 

::~J/~~~~~/ 

...................... (!!!1!J ............... . 

IN SITU' 

SOUTH AND 

UP(-) 

...... -...... -

GEOMAGNETIC 

FIELD 

...... - ...... 

...... -

• 

__ ,.. ..... 

o o@o ® ..... , .. , .... 

FIGURE 151.3.-Portable magnetometer , depicted measuring the magnetic polarity of a reversely magnetized 

sample from the northern hemisphere. 

1s polarity sensitive-a magnetic field directed from 

magnetic west to east will cause a meter deflection to 

the right, .say, whereas a field in the opposite direction 

will cause a deflection to the left. To determine the 

"sense" of the meter deflection, the following procedure may be ti.sed to calibrate a new instrurttent: 

( l) One enct of the detector head is arbitrarily marked ( +). 

(2) 'l'he ne<..·"<:lle of a compass is clamped and the compass is 

placed 1 or 2 meters from the ( +) end of the detector 

head so that the needle is parallel to and in line with the 

detector axis and has its positive or north-seeking end 

ctirected toward the detector head. 

( 3) The compass is moved toward the detector head, keeping 

the needle in line with the detector axis, and the direction 

of the meter deflection as the compass needle approaches 

the detector is marked ( +). This is the deflection to 

be expected if the positive or north-seeking end of a 

remnent-magnetization vector approaches the ( +) of 

the detector; conversely, a deflection in the opposite 

rlirection indicntes that the magnetically negative or 

south-seeking end of the vector is approaching the 

detecto1·. 

As mentioned earlie~, rocks of post-Eocene age that 

are unaffected by lightning may be expected to have 

n. direction of remanent magnetization, after correction for any postemplacement tilting, directed to the 

north and inclined to the horizontal at an angle appropriate to the sampling latitude (see fig. 151.1A.). 

If the rock is normally magnetized, the positive end 

of the magnetizati.on vector is in this direction, and 

if reversely magnetized, the negative end. It is thus 

654685 0-62--8 

necessary to orient or mark the sample by some means 

before it is removed from the outcrop so that this 

expected direction of magnetization within the sample 

may be determined. 

The magnetic polarity may be measured as follows: 

( 1) Holding the sample in its in situ position, a 

( + ) sign is marked at the north end of a vector 

originating at the center of the sample and 

parallel to the "normal" field direction as described above, that is, trending north and, between lat. 30° and 50° N., plunging 49° to 67°; 

a (-) sign ·is marked at the opposite end of 

this vector. 

(2) The sample is held 1 meter from the detector 

· with the ( + ) and (-) signs both alined with 

the detector axis and with the ( +) signs of 

the detector and samples closest together. 

(3) The sample is moved toward the detector; if the 

meter deflection is in the ( + ) direction, the 

sample is magnetically normal, and conversely, 

if the meter· deflection is in the (-) direction, 

the sample is reversed. 

To avoid erroneous determinations due to shape effects or magnetization directions at large angles to 

the expected direction, the determination should be 

repeated by moving the (-) end of the sample toward the ( +) end of the detector. The polarity 

measurement is reliable only if the meter deflects in 

the opposite direction. It is also reassuring to repeat 
D108 GEOLOGICAL SURVEY RESEAR·CH 1 9 6 2 

the determination on at least two additional oriented 

samples from the same unit, separated from each other 

as much as possible-=-preferably at least 10 to 20 meters 

-and if possible representing different mineralogies 

and different rates of cooling. 

With some care, the direction of magnetization of 

equidimensional samples that are neither clearly normal nor reversed may be estimated by keeping the 

sample at a fixed distance from the detector head and 

finding the orientation that gives a maximum deflection. 

An important characteristic of this method of measuring magnetic polarity of hand samples in the field 

is that only the remanent magnetization is measured. 

The induced magnetization of the sample, which is 

parallel to the geomagnetic field and proportional to 

its strength, gives rise to lines of magnetic flux at right 

angles to the detector axis and is thus not measured. 

In the course of sampling lava flows from the islands 

of Hawaii (Doell and Cox, 1961b) and Kauai, from 

Owens Valley, from near Lake Tahoe, Calif., and 

from near Reno, Nev., we have used the techniques 

described . above to determine the magnetic polarity 

of lava flows from which oriented cores were also 

drilled and studied in detail in the laboratory. The 

following is a summary of all field polarity measurements that have also been accompanied by more detailed laboratory measurements. 

Normal flows correctly identified ----------------------- 96 

Normal flows incorrectly identified as reversed --------- 1 

Reversed flows correctly identified --------------------- 23 

Reversed flows incorrectly identified as normal --------- 1 

Flows with intermediate directions or inconsistent magnetizations incorrectly identified as either normal or 

reversed -------------------------------------------- 4 

Flows with intermediate directions or inconsistent magnetizations so identified ----------------------------- 5-10 

(no record) 

We would like to note further that most of the incorrect determinations were made before we gained 

experience in using the method. 

Although a geologist's compass may also be used 

to determine strongly magnetized parts of some lava 

flows (Einarsson, 1957; Rutten, 1960, Muehlberger and 

Baldwin, 1958) the portable magnetometer greatly 

extends the range of magnetic intensities and rock 

types that may be measured by the geologist in the 

field. 

REFERENCES 

Asami, E., 1956, A palaeomagnetic consideration on the remanent magnetization of t.hf>. basalt layers at Kawajirlmisaki, Japan: Jour. Geomagnetism and Geoelectricity, 

v. 8, p. 147-155. 

Brunhes, B., 1906, Recherches sur la direction d'aimantatlon 

des roches volcaniques (1) : Jour. de Physique, 4th series, 

v. 5, p. 705-724. 

Cox, Allan, 1961, Anomalous remanent magnetization of basalt: U.S. Geol. Survey Bull. 1083-E, p. 131-160. 

Doell, R. R., and Cox, Allan, 1961a, Paleomagnetism : Advances in Geophysics, v. 8, p. 221-313. 

-- 1961b, Palaeomagnetism of Hawaiian lava flows: Nature, v. 192, p. 645-646. 

Einarsson, T., 1957, Magneto-geological mapping in Iceland 

with the use of a compass: Philos. Mag., v. 6, p. 232-239. 

Einarsson, T., and Sigurgeirsson, Th., 1955, Rock magnetism 

in Iceland: Nature, v. 175, p. 892. 

Graham, K. W. T., 1961, The re-magnetization of a surface 

outcrop by lightning currents: Royal Astron. Soc. Geophys. Jour., v. 6, p. 85-102. 

Hospers, J., 1954, Reversals of the main geomagnetic field, III: 

Koninkl. Nederlandse Akad. Wetensch. Proc., v. 57, p. 

112-121. 

Matuyama, Motonori, 1929, On the direction of magnetization 

of basalt in Japan, Tyosen, and Manchuria: Japan Acad. 

Proc., v. 5, p. 203-205. 

Muehlberger, W. R., and Baldwin, B., 1958, Field method for 

determining direction of magnetization as applied to late 

Cenozoic basalts of northeastern New Mexico : Jour. Geophys. Research, v. 63, p. 353-360. 

Neel, M. L., 1951, L'inversion de l'aimantation permanente des 

roches: Annales Geophysique, v. 7, p. 90-102. 

Roche, A., 1953, Sur l'origine des inversions d'aimantatlon 

constantees dans les roches d'Auvergne: Acad. Sci. [Paris] 

Comptes Rendus, v. 236, p. 107-109. 

Rutten, M. G., 1960, Paleomagnetic dating of younger volcanic 

series: Sonderdruck Geol. Rundschau, v. 49, p. 161-167. 

Serson, P. H., and Hannaford, W. L. W., 1956, A portable 

electrical magnetometer: Canadian Jour. Technology, v. 1, 

p. 232-243. 

Strangway, D. W., 1961, Magnetic properties of diabase dikes: 

Jour. Geophys. Research, v. 66,_ p. 3021-3032. 

Uyeda, S., 1958, Thermo-remanent magnetism as a medium of 

palaeomagnetism, with special reference to reverse thermoremanent magnetism: Japanese Jour. Geophysics, v. 2, 

p. 1-123. 

Verhoogen, J., 1956, Ionic ordering and self-reversal of magnetization in impure magnetites: Jour. Geophys. Research, 

v. 61, p. 201-209. 

-- 1962, Oxidation of iron-titanium oxides in igneous 

rocks: Jour. Geology, v. 70, p. 168-181. 

Wilson, R. L., 1961, Palaeomagnetism in Northern Ireland: 

Royal Astron. Soc. Geophys. Jour., v. 5, p. 45-69. 

{ 
~· 

ARTICLE 152 D109 

MINERALOGY, GEOCHEMISTRY, AND PETROLOGY 

152. THERMAL EXPANSION OF TEN MINERALS 

By BRIAN J. SKINNER, vVashington, D.C. 

A new heating stage :for the X-ray diffractometer 

described by Skinner, Stewart, and Morgenstern 

( 1962) has been used. to measure the thermal expansion o:f 5 sulfides, 2 selenides, 2 silicates, nnd 1 carbonate. :M:easurement and alinement procedur~s were 

the same as those described by $kinner, Clark, and 

Appleman (1961). For each substance several diffraction lines were measured at eac~ temperature by 

oscillating over each line at %, 0 28 per minute. Copper J(a radiation (a1 = 1.54050A) was used in all 

cases. ~1easurements were made at irregular temperature intervals and in random order to permit 

evaluation o:f any irreversible changes occurring in 

the sample and to ensure that the measurements were 

the same :for both rising and :falling temperatures. 

Diffraction peaks were measured at the intersection. 

o:f the weighted centerline with an average background 

level. The precision or reproducibility o:f measurement is 0.01 .. percent, and comparison o:f our silver 

expansion measurements with those o:f Hume-Rothery 

and Reynolds (1938) suggest that the accuracy is at 

least 0.03 percent. 

Because of their use in thermodynamic calculations, 

. molar volumes ( cc per mol) have been calculated :from 

the unit-cell edge measurements at each temperature. 

Molar volumes were calculated using 6.02472X 1023 

m6l-1 for Avogadro's number (DuMond and Cohen, 

1953). The molar volumes are, therefore, gram-formula volumes on the physical scale o:f atomic weights. 

The change in molar volume with temperature can be 

conveniently expressed by the general :function 

V = A/T + B + OT + DT2 , 

where V is the molar volume in cc per mol and T is 

the absolute temperature. The constants A, B, 0, and 

D were :found with a digital computer by the method 

of least squares. The thermal expansion coefficient 

can be :found by differentiating the :function a~alytically. The determined cell edges and calculated molar 

volumes are listed in table 152.1. The constants o:f 

the derived :functions are listed in table 152.2. 

THERMAL EXPANSION OF GALENA, CLAUSTHALITE, 

AND CADMIAN GALENA 

Galena, c]austhalite, and cadmian galena are isostructural, with space group Fm3m, Z = 4. The syn500 

TEMPERATURE, IN DEGREES CENTIGRADE 

FIGURE 152.1.-Change in cell edge (a) of galena (PbS), 

clausthalite (PbSe), and a cadmian galena with change in 

temperature. 

thetic PbS, PbSe, and a cadmian galena, with the 

reported composition (Pb0 •8a73Cd0 •1627 ) S, that were 

used for the present study were prepared and described by Bethke and Barton ( 1961). The thermal 

expansion, measured in a vacuum, was computed :from 

the measured positions o:f the ( 420), ( 422), and ( 511) 

reflections. Plots of unit-cell edge versus temperature (fig. 152.1) are nearly parallel :for the three compounds. The cell edges of PbS and PbSe at 25 oc, 

and o:f the cadmian galena at 26.2°C in table 152.1 

are those reported by Bethke and Barton ( 1961). The 

parameters o:f the :functions describing the molar volume expansions are given in table 152.2. 

The only previous expansion measurements of PbS 

are those by Pfaff (1859) and Sharma (1951). Pfaff 

observed a 0.15~percent linear expansion between 20°C 

and 100°C. In the present study a 0.162-percent increase was observed in the same interval. Sharma 

( 1951) measured the linear expansion of a galena 

crystal by the interferometer method. ·The data are 

in good agreement below 300°C, but from 300°. to his 

highest temperature of measurement, 375°C, Sharma 

observed a significantly greater expansion than that 

found in the present study. The reason for the disagre~ment above 300°C is not known. 
DllO GEOLOGICAL SURVEY RESEARCH 19 6 2 

THERMAL EXPANSION OF SPHALERITE, STILLEITE, 

AND A CADMIAN SPHALERITE 

Sphalerite ( ZnS), stilleite ( ZnSe), and a cadmian 

sphalerite with the reported composition (Zn0 •9382 

C~o.o6Is) S are cubic and isostructural, space group 

F431n,_Z = 4. The synthetic ZnSe used for the present study is that reported by Bethke and Barton 

( 1961). The cadmian sphalerite was prepared for the 

study by P. M. Bethke. Expansions were computed 

from measurements of the ( 331) and ( 422) reflections 

at various temperatures. 

The cell edge versus temperature plots for the three 

compounds are essentially parallel (fig. 152.2), analogous to the behavior of the three galena-type compounds. The cell edge of sphalerite at 25°C in table 

152.1 is that reported by Skinner, Barton, and Kullerud (1959) and of ZnSe at 25°C ·by Bethke and 

Barton ( 1961). · . 

Parameters of the functions describing the molar 

volume expansions are given in table 152.2. It is significant that in both the sphalerite-type and the 

galena-type compounds described, compositional differences do not markedly change the slope of the 

expansion curves (figs. 152.1 and 152.2) . 

THERMAL EXPANSION OF WU'RTZITE 

Wurtzite (ZnS) is hexagonal, space group P63mo, 

Z = 2. Synthetic wurtzite with the 2-layer (2H) 

stacking sequence. was synthesized at 1100°C. The 

expansions of a and· c were computed from the measured positions of the (210), (300), (203), and (114) 

reflections at various temperatures. The. expansion is 

anisotropic but continuous over the temperature range 

of measurement. Parameters of the function describing the molar volume expansion are given in table 

152.2. 

/" 

o/o" 

o/co 

o·o / 

0/0/ 

.0/ 

8.50r 

1 ----0 ..c o--o-o b 

o-o·o----------- 8.42 0--0--- :-o-0 -j a 

I I I 500 800 

TEMPERATURE, IN DEGREES CENTIGRADE 

FIGURE 152.3.-Change in cell edges (a, b, c) of strontianite 

(Sr003 ) with change in temperature, demonstrating the 

large anisotropism of expansion. 

THERMAL EXPANSION OF STRONTIANITE 

Strontianite (SrCOa) is orthorhombic, space group 

Pnam, Z, = 4. The thermal expansion of analytical 

reagent-grade SrC03 was measured under 1 atmosphere of C02 pressure up to 900°C, from the measured displacement of the (200), (041), and (002) reflections. 

The expansion is strongly anisotropic (fig. 152.3), 

the relative expansion of the c-axis being several times 

greater than that of the a-axis. Parameters of the 

function describing the molar volume expansion are 

given in table 152.2. 

THERMAL EXPANSION OF COESITE 

~ Coesite (Si02 ) is monoclinic, but dimensionally 

· hexagonal, with a = c and f3 = 120°. Zoltai and 

Buerger ( 1959) chose to orient coesite in the mono500 

TEMPERATURE, IN DEGREES CENTIGRADE 

FIGURE 152.2.-Ghange in cell edge (a) of sphalerite (ZnS), 

stilleite (ZnSe), and a cadmian sphalerite with change in 

temperature. 

clinic first setting to emphasize its dimensional hexagonal symmetry so that a = b and y = 120°, and in 

this setting the space group is B2/b\ Z = 16. 

A synthetic coesite synthesized at 1100°C and 40 

kilo bars pressure by F. R. Boyd was used for the expansion measurements a.nd the expansion calculated 

from the movement of the (421) and ( 170) reflections. 

Coesite remains dimensionally hexagonal, within the 

resolution of the present measurements, up to 1045°C. 

1 In the standard or monoclinic second setting, the space group ls 

02/C. 

J. 
• 

ARTICLE 152 Dill 

If significant deviations from hexagonal dimensions 

occurred (that is, a =1= b or y =1= 120°), the X-ray reflections would become broad and eventually split. 

Bec~tuse this did not happen, at least up to 1045°C, 

only 2 independent measurem~nts were necessary for 

determining the thermal expansion, instead of the 4 

reflections normally required to characterize a monoc.linic crystal uniquely. The parameters.of the molar 

volume expansion function are given in table 152.2. 

THERMAL EXPANSION OF FORSTERITE 

Forsterite (l\ig2Si04 ) is orthorhombic, space group 

Pbn1h, Z = 4. · The sample studied was a synthetic 

forsterite prepared by I-I. S. Yoder, Jr. The measured cell edges at 25°C are in reasonable agreement 

with those reported by Yoder and Sahama (1957) and 

by Swanson and Tatge (1953) for pure forsterite. 

TABLE 152.1-Unit-cell edges and molar volumes at different 

temperatures of ten minerals 

'l'cmpcruturo (

0 C) I a (A) b (A) '(A) I 

15.0 __ --------- 22.0-----------

25.0 __ --------- 53.5 __________ _ 101.0 _________ _ 

159.0.--------- 217.0 _________ _ 

281.0_---------

298.2_ --------- 336.0 ___ ------- 399.2 ___ ------- 441.2_ --------- 489.2.---------

540.0.---------

607.0.---------

25.0 __ --------- 26.5 .. --------- 63.0-- - - - - - - - - - 136.0 _________ _ 187.2 _________ _ 

233.0'- --------- 287.0 ___ ------- 350.1.---------

408.3.---------

485.5.--------- 562.0 _________ _ 

591.0.---------

25.0 __________ _ 26.2 __________ _ 98.2 __________ _ 

184.2_--------- 202.0 _________ _ 

285.3_ --------- 388.0 _________ _ 

Galena (PbS) 

5. 9339 

5. 9352 

5. 9358 

5. 9389 

5. 9440 

5. 9517 

5. 9582 

5. 9665 

5. 9700 

5. 9738 

5. 9812 

5. 9879 

5. 9943 

6. 0010 

6. 0122 

Clnusthnllte (PbSe) 

6. 1254 

6. 1257 

6. 1294 

6. 1393 

6. 1460 

6. 1509 

6. 1595 

6. 1673 

6. 1746 

6. 1850 

6. 1948 

6. 1987 

Cadmlnn galena [(Pbo.amCdo.Im)S] 

5. 8674 

5. 8676 

5. 8768 

5. 8880 

5. 8907 

5. 9014 

5. 9144 

V (cc per mol) 

31. 470 

31. 491 

31. 500 

31. 550 

31. 631 

31. 754 

31. 858 

31. 992 

32. 048 

32. 109 

32. 229 

32. 337 

32. 441 

32. 550 

32. 732 

34. 616 

34. 621 

34. 684 

34. 852 

34. 967 

35. 050 

35. 198 

'35. 332 

35. 457 

35. 637 

35. 806 

35. 874 

30. 424 

30. 427 

30. 570 

30. 745 

30. 788 

30. 956 

31. 161 

TABLE. 152.1-Unit-cell edges and molar volumes at dijj"eren! 

temperatures of ten minerals-Continued· 

11.0 __________ _ 20.L _________ _ 23.2 __________ _ 25.0 __________ _ 

54.4 __ -- ------- 118.3 ___ -- -----

175.7----------

205.5_---------

280.0_---------

357.2_ --------- 416.1_ ________ _ 

456.0_ --------- 512.6 _________ _ 542. L ________ _ 

602.3_- -------- 693.5 _________ _ 727.0 _________ _ 

79 7. 7- - - - - - - --- 867.0 _________ _ 

870.5_ --------- 946.0_---------

20.0 ______ ·--~- 25.0 __________ _ 67.L _________ _ 

138.4_---- ----- 175.2 _________ _ 

222.5_---------

279.1_ __ ------- 337.0 _________ _ 

398.0---------- 446.2 _________ _ 521.5 _________ _ 

586.0_--------- 639.2 _________ _ 731.1_ ________ _ 

25.0 __________ _ 

100.0_--------- 214.5 _________ _ 316.5 _________ _ 

414.0_--------- 511.2 _________ _ 

633.3- - - - - - - - - - 747.0 _________ _ 843.1_ ________ _ 

25.0 ___________ 131.5 __________ 

244.8_---------

359.5_---------

477 .5_---------

556.7----------

607 .0_--------- 678.5 __________ 

689.8.--------- 781.9 __________ 

909.0 __________ 829.0 __________ 1 

a (A) b (A) 

Sphalerite (ZnS) 

5. 4084 

5. 4090 

5. 4092 

5. 4093 

5. 4104 

5. 4130 

5. 4148 

5. 4165 

5. 4195 

5. 4226 

5. 4257 

5. 4280 

5.·4307 

5. 4324 

5. 4352 

5. 4400 

5. 4411 

5. 4444 

5. 4481 

5. 4485 

5. 4520 

Stlllelte (ZnSe) 

5. 6680 

5. 6685 

5. 6694 

5. 6728 

5. 6743 

5. 6764 

5. 6793 

5. 6821 

5. '6851 

5. 6873 

5. 6914 

5. 6958 

5. 6978 

5. 7029 

c (A) I 

Cadmian sphalerite [(Zno.g3&2CDo.O&I8)S] 

5. 4354 

5. 4389 

5. 4438 

5. 4485 

5. 4524 

5. 4574 

5. 4629 

5. 4686 

5. 4734 

. Wurtzite (ZnS) 

3. 8232 ---------- 3. 8260 ---------- 3. 8293 ---------- 3. 8343 ---------- 3. 8379 ---------- 3. 8411 ---------- 3. 8434 ---------- 3. 8464 ---------- 3. 8468 ---------- 3. 8510 ---------- 3. 8533' ---------- 3. 8570 ----------

6. 2565 

6. 2610 

6. 2668 

6. 2717 

6. 2781 

6. 2839 

6. 2849 

6. 2884 

6. 2896 

6. 2938 

6. 2973 

6. 3018 

V (cc per mol) 

23. 828 

23. 836 

23. 838 

23. 840 

23. 854 

23. 889 

23. 912 

23. 935 

23. 975 

24. 016 

24. 057 

24. 087 

24. 124 

24. 146 

24. 184 

24. 248 

24. 263 

24. 307 

24. 356 

24. 362 

24. 409 

27. 426 

27. 434 

27. 447 

27. 496 

27. 518 

27. 548 

27. 591 

27. 631 

27. 675 

27. 707 

27. 767 

27. 832 

27. 861 

27. 936 

24. 188 

24. 233 

24. 299 

24. 362 

24. 414 

24. 481 

24. 555 

24. 632 

24. 697 

23. 858 

23. 910 

23. 973 

24. 054 

24. 124 

24. 187 

24. 220 

24. 271 

24. 281 

24. 350 

24. 393 

24. 457 
D112 GEOLOGICAL SURVEY RE.SEAR·CH 19 6 2 

TABLE 152.1-Unit-cell edges and molar volumes at different 

temperatures of ten minerals-Continued 

Temperature (°C) I a (A) b (A) 

Coesite (Si02) 

24.3 ___________ 7. 1517 ---------- 128.0_--------- 7. 1534 ---------- 238.5 __________ 7. 1560 ---------- 350.5 __________ 7. 1586 ---------- 464.2_--------- 7. 1617 ---------- 603.0 __________ 7. 1655 ---------- 672.3_--------- 7. 1677 ---------- 780.0_--------- 7. 1712 ---------- 872.0_--------- 7. 1746 ---------- 991.3_--------- 7. 1785 ---------- 1045.3 __ ------- 7. 1807 ----------

25 ______________ 4. 758 10. 214 81.1_ __________ 4. 760 10. 220 

113.7---------- 4. 761 10. 223 161.9 __________ 4. 763 10. 229 

206.3_--------- 4. 766 10. 234 

291.6_--------- 4. 769 10. 245 

358.2_--------- 4. 772 10. 253 

425.5_--------- 4. 776 10. 264 

530.6---------- 4. 779 10. 282 

572.3_------ _._- 4. 783 10. 289 

661.6- - - - - - ..: - - - 4. 788 10. 305 

7 42.7---------- 4. 793 10. 316 

904.2_--------- 4. 802 10. 344 1041.8 _________ 4. 810 10. 368 

1127.L ________ 4. 816 10. 382 

Strontianite (SrCOa) 

25.0_---------- 5. 1120 8.4145 

30.0_---------- 5. 1125 8. 4155 112.2 __________ 5. 1150 8. 4235 

230.1_--------- 5. 1199 8. 4370 272.5 __________ 5. 1226 8.4410 

296.0_--------- 5. 1235 8.4440 

495.0_--------- 5. 1330 . 8. 4650 

585.5---------- 5. 1380 8. 4755 

610.2_--------- 5. 1400 8. 4785 

725.5_--------- 5. 1465 8.4926 

900.0_--------- 5. 1558 8. 5175 

c (A) 

12. 3791 

12. 3828 

12. 3864 

12. 3907 

12. 3957 

12. 4030 

12. 4066 

12. 4125 

12. 4181 

12. 4254 

12. 4290 

5. 984 

5.987 

5.989 

5. 992 

5. 995 

6. 000 

6. 007 

6. 014 

6. 020 

6. 026 

6. 031 

6. 036 

6. 055 

6. 069 

6. 077 

6. 0286 

6. 0306 

6. 0530 

6. 0810 

6. 0935 

6. 0994 

6. 1548 

6. 1820 

6. 1922 

6. 2270 

6. 3000 

V (cc per mol) 

20. 647 

20. 663 

20. 685 

20. 706 

20. 732 

20. 767 

20. 786 

20. 815 

20. 845 

20. 880 

20. 899 

43. 802 

43. 87 

43. 90 

43. 97 

44. 04 

44. 15 

44. 27 

44. 41 

44. 55 

44. 67 

44. 82 

44. 95 

45 30 

45. 59 

45. 77 

39. 058 

39. 080 

39. 281 

39. 564 

39. 685 

39. 745 

40. 280 

40. 548 

40. 645 

40. 993 

41. 670 

The linear expansions parallel to the three crystallographic axes, computed from the measured positions 

of the (112), (140) and (211) reflections, can be compared qualitatively with the expansions observed by 

Kozu and others ( 1934) for a natural olivine with the 

composition forsterite 89.9 percent, fayalite 10.1. In 

both .cases the relative expansions parallel to the b and 

c axes are approximately equal, but the expansion 

parallel to the a axis is Gonsiderably less. The only 

previous measurement reported for a pure forsterite 

is that of Rigby and Green ( 1941), who measured the 

bulk expansion of a random aggregate of forsterite 

grains. The percentage volume expansion from 20°C 

TABLE 152.2.-Coefficients in the equation V=*+B+CT+DT2 

[The function is calculated by the method of least squares, giving the value at 298.2u 

Absolute (25° C) three times the weight of other values. The agreement of fit is 

shown by the standard deviation between the observed and calculated values] 

Substance A B c D Standard 

deviation 

Galena (PbS) _______ -47.689 31.304 0. 9244X1o-a 8. 5282X10-o7 o. 008 

Clausthalite (PbSe)_ 58.105 33.621 2. 7618X10-3 -2. 7220X10-7 .006 

~Pbo.s373Cdo.t627) S ____ 125.58 28.922 4. 0642X10-8 -14. 623X10-7 .003 

phalerite (ZnS) __ -~ 24.427 23.552 . 6865X10-8 . 0084X10-7 .003 

Stilleite (ZnSe) ______ 30.002 27.100 . 7649X10-8 . 3994X10-7 .004 

(Zno.gaszCdo.06t~) S __ -- -5.014 24.056 . 4719XlO-a . 9725Xl0-7 .003 

Wurtzite (ZnS) _____ 11.407 23.659 . 4946X10-a 1. 4501 Xl0-7 .003 

Strontianite 

(SrCOa)- ---------- -129.21 39.214 . 5082X10-8 14. 259 X10-7 .009 

Coesite (Si02>------- 2. 451 20.596 .1212X10-8 . 8147X10-7 .001 

Forsterite 

(M:g2Si 04) --- ______ 45.31 43.21 1.368 xw-a 3.113 X10-7 .011 

to 1000°C observed by Rigby and Green (1941) is 

3.42 percent, in comparison to the 3.86 percent observed in the present study. This should be considered only fair agreement, and indicates a need for 

further independent measurements. 

REFERENCES 

Bethke, P. M., and Barton, P. B., Jr., 1961, Unit-cell dimension versus composition in the systems PbS-Cds, PbS-PbSe, 

ZnS-ZnSe, and CuFeS1.

90-CuFeSe1 .90 : Art. 114 in U.S. 

Geol. Survey Prof. Paper 424-B, p. B26~B270. 

DuMond, J. W. M., and Cohen, E. R., 1953, Least squares adjustment of the atomic constants, 1952: Rev. Modern 

Physics, v. 25, p. 691-708. 

Hume-Rothery, W., and Reynolds, P. W., 1938, A high-temperature Debye-Scherrer camera : Royal Soc. London Proc., 

v. A167, p. 25-34. 

Kozu, S., Ueda, J., and Tsurumi, S., 1934, Thermal expansion 

of olivine: Imp. Acad. Japan Proc., v. 10, p. 83-86. 

Pfaff, F., 1859, Untersuchungen uber die Ausdehnung der 

Krystalle durch die Warme: Poggendorff, Ann. der Physik 

und Chemie, B107, p. 148-154. 

Rigby, G. R., and Green, A. T., 1941, Thermal expansion characteristics of some calcareous and magnesium minerals : 

British Ceram. Soc. Trans., v. 41, p. 123-143. 

Sharma, S. S., 1951, Thermal expansions of crystals VIIIGalena and pyrite: Indian Acad. Sci. Proc., v. 34, p. 72-75. 

Skinner, B. J., Barton, P. B., Jr., and Kullerud, G., 1959, 

Effect of FeS on the unit cell edge of sphalerite-A revision: Econ. Geol., v. 54, p. 104Q-1046. 

Skinner, B. J., Clark, S. P., Jr., and Appleman, D. E., 1961, 

Molar volumes and thermal expansions of andalusite, kyanite and sillimanite: Am. Jour. Sci., v. 259, p. 651-668. 

Skinner, B. J., Stewart, D. B., and Morgenstern, J. C., 1962, 

A new heating stage for the X-ray diffractometer: Am. 

Mineral., v. 47, p. 962-967. 

Swanson, H. E., and Tatge, E., 1953, Standard X-ray diffraction patterns: Natl. Bur. Standards Circ. 539, v. 1, 95 p. 

Yoder, H. S., Jr., and Sahama, Th. G., 1957, 01ivine X-ray 

determinative curve: Am. Mineral., v. 42, p. 475-491. 

Zoltai, T., and Buerger, 1\f. J., 1959, The crystal structure of 

coesite the dense, high-pressure form of silica: Zeitschr. 

Kristallographie, v. 111, p. 129-141. 

-. 
' l 

ARTICLE 153 D113 

153. HYDROTHERMAL ALTERATION IN DRILL HOLES GS-5 AND GS-7, STEAMBOAT SPRINGS, NEVADA 

By Guol\fUNDUR E. SmvALDASON 1 and DoNALD E. WHITE, Menlo Park, Calif. 

Sigvaldason and Whi~ (1961) described briefly the 

hydrothermal mineral assemblages in two drill holes 

( GS-1 and GS-2) in the Low and High Terraces, 

respectively, at Steamboat Springs and included bibli-

·ographic references to previou~ work. 

DRILL HOLE . Gs-5 

Drill hole GS-5 is on the Main Terrace near the 

principal flowing springs and is between· the drill 

holes previously described on the low and high terraces respectively. Semiquantitative abundance of the 

principal minerals and other pertinent data are shown 

in figure 153.1 ; analyses of the altered rocks are shown 

in table 153.1. The most abundant clay mineral is 

mixed-layer illite-montmorillonite. The expandable 

montmorillonite component constitutes about 20 to 25 

percent of the mixed layers in much of the granodi-

. orite, but 10 percent or less in the dikes and in· the 

most completely altered granodiorite. Below 350 feet, 

a relatively well-crystallized hydrothermal mica occurs with na > 1.55 and with high birefringence, and 

is here called "sericite." This mineral probably grades 

into the more abundant illite-mo~tmorillonite, characterized optically by finer grain size, na < 1.55 and 

typically near 1.53, and lower birefringence. All of 

the hydrothermal mica is of the 1 Md dioctahedral 

type, now recognized also in cores from GS-2, and 

with less certainty in cores from GS-1 and GS-7, 

where it is greatly dominated by montmorillonite. 

Chlorite with a relatively high iron content is present in small amount throughout the core and is generally more abundant in the altered dikes than in 

granodiorite. The intensity ratios of the ( 001) and 

(002) X-ray peaks suggest that chlorite has a higher 

Mg content in the upper part of the andesite dike 

than elsewhere. 

Hydrothermal !(-feldspar is relatively abundant 

from about 100 to 300 feet in depth, generally replacing plagioclase irregularly, and is commonly marginal to patches of completely argillized plagioclase. 

The sodic rims of zoned plagioclase crystals are very 

resistant to alteration. The andesine cores of crystals 

are commonly replace~ completely in the upper part 

of the hole by illite-montmorillonite and K-feldspar. 

1 Present address, University Research Institute, Reykjavik, Icelapd. 

Below 300 feet K-feldspar is increasingly scarce, and 

the original zoned plagioclase is commonly "homogenized" to albite or sodic oligoclase with abundant 

patches and flecks of clay minerals or calcite; excess 

calcium is removed. Original hornblende and biotite 

are completely altered throughout the hole, but original quartz and orthoclase are stable or metastable. 

Chalcedony-quartz-calcite veins occur below 84 feet, 

with ·calcite· as an abundant component below 175 

feet; vein thicknesses range up to about 8 feet. Stibnite is relatively common near the surface, decreasing 

in abundance downward to 94 feet; it has not been 

observed from greater depths. 

The mineral assemblages in drill hole GS-5 are similar to those of GS-2 of the High Terrace in the 

downward decrease in hydrothermal K-f~ldspar and 

plagioclase, and in the general increase downward in 

clay minerals (see Sigvaldason and White, 1961, for 

possible explanations): Addition of potassium is nowhere as notable in GS-5 as in the upper 300 feet of 

GS-2. At least in part this is related to proportions 

of reactive calcic plagioclase and perhaps even to 

structural states of plagioclase in plutonic rocks and 

in volcanic rocks. The present composition of the 

thermal waters of the two terraces is similar ( Sigvaldason and White, 1961, p. D121). 

DRILL HOLE Gs-7 

Drill hole GS-7 is situated in the Silica Pit area 

on higher g~ound a mile west of the flowing springs 

(White, 1955, p. 110-111). Although thermal potassium-bearing waters probably discharged from this 

area several hundred thousand years ago, activity at 

present and in the recent past consists of the rise of 

steam, C02, and H 2S into a perched body of water 

dominantly of meteoric origin, with a well-defined 

water table near a depth of 112 feet. In contrast to 

the discharging water of the active spring terraces, 

the perched water body contains bicarbonates and sulfates almost to the exclusion of chloride, boron, and 

cations of external origin. Possible origins of this 

type of water have been reviewed briefly by White 

(1957, p. 1649-1651,-1655). H2S rises above the water table and oxidizes near the surface to form sulfuric acid. 
D114 

60 

0 

50 

100· 

150 

200 

250 

.... 

~ 

~ 

~ 

!: 300 

-£ 

.... 

~ 

~ 

0 

350 

400 

450 

500 

550 

600 

GEOLOGICAL SURVEY RESEAR•CH 1 9 6 2 

TEMPERATURE, IN °C 

80 100 120 140 160 

'-.... ......... 

~ ~ 

~ 

~ 0 

180 200 

Condensed 

220 loa 

()p811ne 

s Inter 

Dlsc:onfonnlty 

helcedonic Vc sinter 1\_ Dlsc:onformity 

\ l\ Theoreticel boilina points for AI luvlum pure water; water level 5 ft above around 

4 

~\ \~ 

\ Bottom-hole temperltures obtlined \ as drllllna prqrnsed - "<. \ 

\ 

\ 

\ e Repeet meeaurementa efter lntervel · \ with no drlllina 

~ 

u 

T 

u 

nconlormity(7) 

uff·breccil 

nconformlty 

v elns 

v eln 

v elns 

v ein 

v ein 

v ein 

v eln 

A ndesite dike 

Socii trechyte 

dike 

G 

res renodiorite 

reccla with anclealne 

Gr enodlorite 

.... 

~ 

~ 

~ 

!:. 

-£ 

.... 

~ 

~ 

0 

15 

19 

84 

109 

126 

136 

140 

155 

174 

195 

220 

264 

306 

373 

450 

464 

482 

492 

507 

512 

~J~ 535 

546 

562 

572 

574 

0 

APPROXIMATE PERCENTAGE 

OF PRINCIPAL MINERALS 

20 40. 60 80 

Opaline sinter with cristobalite and chalcedony 

in aeneral increasina downward to 80 ft; 

chalcedonic sinter with cristobalite 80 to 

84ft 

Alluvium with hydrothermel quartz, illite, 

K-feldspar. 'pyrite, and marcasite 

FIGURE 153.1.-Data from drill hole GS-5, _main terrace, Steamboat Springs. Altitude of ground level is 4,661 feet. 

100 

The striking differences in the mineral assemblages 

(fig. 153.2 and table 153.2) from the surface to depths 

of more than 150 feet are related to downward percolation of very acid water (pH probably initially 1 

to 2) through porous siliceous residues of previously 

leached granodiorite. Opal has the X-ray pattern of 

·

., 
., 

., 

ARTICLE 153 D115 

TABLE 153.1.-Analyses of hydrothermally altered rocks of drill hole GS-5 

[Analyzed by rapid methods by L. Shapiro, H. F. Phillips, K. E. White, S.M. Berthold, and E. A.. Nygaard] 

Rock type, and depth, in feet 

Opaline sinter Black opal sinter Chalcedony-opal Arkosic sediments Chalcedony vein Granodiorite Granodiorite 

sinter (?) 

15 155 306 

SlOt-----·--···--·--·-·-···· 95.2 91.9 96.3 97.2 89.2 81.0 69.9 

AhOa ••.•••• -----····---·--· . 25 . 11 

~:~!·.-_::::::::::::::::::::: } . 0 . 0 

MgO .•.••• -------------·--· . 04 . 00 CaO--------·--------------· .18 . 70 

.72 10.3 4.8 9. 6 14.6 

.05 { . 5 .8 .3 .0 .4 .0 .3 .02 . 25 .30 .31 . 44 .26 .92 .30 .45 .93 

NatO----------------------· . 22 . 26 KsO--------·--------------- .10 .18 TIOs-------·---------·-·--- . 00 . 06 

. 24 1.1 .22 .66 2.4 .16 5. 6 1.3 4.3 5.8 .16 .34 .16 .16 .30 

PsOa------------------------ . 00 . 01 .00 .02 .00 .00 .07 

MnO-------·---·--·-·------ . 00 . 01 .00 .01 .00 .00 . 01 

COt------·-·······--·····-- <. 05 <. 05 <.05 <.05 <.05 <.05 <.05 

HtO·-····-·--·--·---··--··· 3. 7 6. 6 1.6 1.6 1. 3 1. 3 1.2 

FeSt---·---···-···-······--- . 13 . 11 , ____________ , _______________ , _____________ . 52 , _____________ 1.4 , _____________ 1.6 , _____________ 1.5 , ___________ 3. 6 ___ Total as reported......... 99.8 99.9 

Specific gravity (powder)___ 2. 16 Specific gravity (lump)..... 2. 04 Prominent hydrothermal Opal, (chalcedminerals.' onyl stibnite, calc te). 2.06 

1. 92 Cristobalite, 

(quartz, stibnite). 

Granodiorite 

450 

8101--------·--------.--••• -•• --· ·-.-·-----· ----- 65. 4 

AhOa .•••. ----·-··-···--··-··--·-····-··-····-·· 13.6 

~:~;i:::::::::::::::::::::::::::::::::::::::::: { : f 

MgO·-·······-·-····-··-··-·--·--····--·-·-·-·-- 1. 0 

CaO.----·-·····--·················-·······-·--- 4. 2 

NatO-.---·-·-----------------··-----·-·--·----- 2. 0 

KsO.-------··-----------·--··-·---·-·-·----··--- 4. 4 Tt o,. __ . ____ . ____ . _. _. _. ____ . _. ______ ~ _. ____ .. _. . 30 

P10a •• --------------··--·--·---------·--·-··---- . 08 MnO.-••• ·--·----·--·------------·-·----·----·- . 10 COt----------------·--···--·-·-······-·--·----·· 2. 6 HsO.·-------···-·------------------------·--···- 2. 0 Fes, ___ ----------· -·-·-·-··-·-·--------··---·-·· 3. 2 

100.0 

2.40 

2.07 Chalcedony, cristobalite, (py- rite, calcite). 

Andesite dike 

482 

65.4 

16.4 

.8 

.4 

. 70 

.65 

.66 

4.2 

. 52 

.20 

.06 

<.05 

5. 2 

5. 2 

101.6 

2.58 

2. 41 Quartz, K-Celdspar, illitemontmorillonite, (pyrite). 

Andesite di~e 

512 

66.6 

16.1 

.3 

.0 

1.4 

.31 

.54 

4.2 

.47 

.23 

.00 

<.05 

3.4 

5.8 

100.0 

2.66 

2. 55 Chalcedony, il- lite-montmorillonite, (K-feld· 

spar, pyrite, marcasite.) 

Trachytic andesite dike 

532 

64.0 

16.5 

.7 

.7 

1.1 

.94 

2.8 

4.0 

.49 

.09 

.03 

.08 

4.2 

4.3 

99.9 99.3 

2. 64 2. 68 2. 56 2.52 Quartz, illite- Illite (r~-y.-..1.545) 

montmorillon- chtorite, K-feld· 

ite, (K-feldspar, spar, (albite, calcite, pyrite, pyrite). hematite). 

Granodiorite Granodiorite 

562 574 

68.0 67.1 16.0 14.5 2.1 1.9 .8 .. 4 . 61 .68 2. 5 1. 4 3.2 3.2 3.5 4. 6 .47 .49 .12 .08 .10 .11 .68 .67 1.3 2.8 .so . 77 

I-------------I~------------·I-------------I-------------1-------------I----------~- Total as reported-----------------·------------ 99.3 

Specific gravity (powder)._.-----------·--···--- 2. 66 Specific gravity (lump)__________________________ 2. 29 

Prominent hydrothermal minerals'-----··----·· lllite-montmorll1 Or total Fe as Fcs03. 

lonite, "sericite", albite, 

chlorite (cul- clte, pyrito). 

' Approx!mate order of abundance; minor minerals in parentheses. 

98.4 

2. 68 2. 21 lllite-montmorillonite, quartz, chlorite, albite, (pyrite). 

cristobalite to a depth of 32 feet but is amorphous at 

greater depths. The perched body of ground water· 

is strongly acid immediately below the water table to 

132 feet, where kaolinite is most abundant. At 133 

feet montmorillonite abruptly becomes dominant and 

is abundant at all greater depths. l(aolinite was not 

found below 238 feet, marking the lower limit of in99.4 99.9 100.2 98.7 

2. 76 2.68 2.66 2. 62 2.33 2.38 2.49 2.35 Illite-montmoril- Illite-montmortl· lllite-montmoril- lllite-montmorlllonite, quartz, lonite, quartz, lonite, chlorite, lonite, chlorite, 

chlorite, albite, albite, chlorite, (calcite, "seri- albite, (calcite, (pyrite). (pyrite, cal- cite", pyrite). hematite). cite). 

fluence of sulfuric acid of surficial origin. The basal 

(001) X-ray reflection of the montmorillonite is uniformly near 15 A, indicating a Ca-Mg type similar 

to the dominant type in GS-1 ( Sigvaldason and 

White, 1961), and this is supported by double lowtemperature differential thermal analysis peaks characteristic of many Ca-montmorillonites. Chlorite is 
D116 GEOLOGICAL SURVEY RESEARCH 19 6 2 

TEMPERATURE, IN °C 

1-

1.1.1 

1.1.1 

LL. 

~ 

::i 

1-

0.. 

1.1.1 

0 

0 

50 

100 

150 

200 

250 

300 

350 

400 

450 

Condensed 

APPROXIMATE PERCENTAGE 

OF PRINCIPAL MINERALS 

20 40 60 80 100 120 140 160 180 log 0 20 40 60 80 

I~ ~--

-........ ......... 

~ ',, 

1', Estimated original ground tempera-

~ tures before drillin11 

~ 

',( I \ 

I Water tabla before 

·'< 

V drillin11 

~~ 

~ N ~'"""" boll I" ool•b fM "'" water; water level 110 It 

below surface 

/_ 

k' ~ '{ Bottom-hole temperatures obtained -z--- as drilling progressed 

~, 

~\ -1 \ 

1\ \ ~ \ I ' eRepeat measurements after interval t It with no drilling 

l Measul'l!d depth of hole t--H \ Drilled depth 1 

I 

I 

! 

Acid· 

leached 

granodiorite 

above 

water 

table 

Water 

table 

Acid· 

altered 

grano· 

diorite 

Altered 

arano· 

diorite 

Altered 

pyroxene 

andesite 

dike 

Altered 

granodiorite 

20 

68 

111 

114 

120 

127 

132 

133 

145 

170 

198 

217 

238 

253 

257 

264 

281 

288 

312 

328 

335 

343 

358 

375 

385 

I 

Opal (cristobalite) I 

I 

I 

I 

I Quartz (relict) 

Opal (amorphous) I 

I 

I 

I 

I _ .QI!!IJ.a~~~o~~o- ~ ____ -.. 

),.,.... Alunite -----j 

-----;;--==--=-.._ ____ T-"f 

., r/" l ' .'!:! 11 -.. I f ~ It ~ {?/ I 

"' I I ::: /.~~ I :.:: (~( ~ 11 Q) I I~ ! ~~ ~ I 1 ,1 I I ..!!! l 1 lfChloride .l!! t;l ~ 1 

10 =-·-~ .1..{ ~,. I JJ.Some biotite .. / /· ~ 1 ° I 

'-"!--.. ~< -!~ : ', ', S ......_ ~ \ I ........ ........... :::E -.::......_ \ I 

~"' ..... ~ ).), J 

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

I 

I 

1i I . ~ I 

:! 

..:: I 

I 

I 

p----J 

I 

I 

I 

I t:! I (U 

I 5 

I 

I 

I 

I 

FIGURE 153.2.-Data from drill hole GS-7, Silica Pit area, Steamboat Springs. Altitude of ground level is about 5,025 ft. 

100 

present below 270 feet and also occurs in small amounts 

at 198 feet. Below 330 feet "sericite," optically similar to that of GS-5, is found. Relict biotite occurs 

only in relatively fresh rocks containing some unreplaced andesine. 

hole GS-7 is C02. Potassium is not being supplied 

from depth at the ·present time but probably was in 

the past. Excess potassium and aluminum in the 

rocks immediately below the water table (table 153.2) 

were supplied by acid leaching of rocks near the 

The active agent for the deep alteration in drill surface. 

' 
~ 

. , 

ARTICLE 153 D117 

TABLE 153.2.-Analyses of hydrothermally altered rocks of drill-hole GS-7 

[A~alyzod by rapid methods by L. Shapiro, H. F. Phillips, K. E. White, S. M. Berthold, and E. A. Nygaard; Sb by F. N. Ward] 

Rock type, and depth, in feet 

Granodiorite Granodiorite Granodiorite Granodiorite Granodiorite Granodiorite Granodiorite Granodiorite 

20 68 111 114 120 127 133 145 

SlOt •••.•...•.•..•...•. 95.4 92.0 90.5 56.9 21.8 26.8 69.4 69.6 AhO •••••.•....•..•.•.. .68 . 76 .58 15.1 29.0 27.9 15.6 12.0 

~~~a·c::::::::::::::: } .06 .0 .0 .0 .0 .0 .0 .1 .0 MgO ••••••.•.•••.••••. . 01 . 01 .00 .03 .00 .00 2.1 2.6 cao ___________________ .14 .04 .12 .04 .12 .08 .53 .62 

Na'O·----------------- K,o .18 .18 .18 .20 . 31 .32 .22 . 28 ___________________ .08 .14 .16 4.1 7. 9 7.4 3.0 2. 2 

TiOt------------------- .38 .44 .56 .28 .26 .30 .32 .22 

PtOa----------·-------- .00 . 01 .02 .16 .42 .30 .06 .04 

MnO •• --.•...•...• ---- .00 .01 .00 .00 .01 .00 .09 .12 co, ___________________ H,o <.05 .07 .06 .23 .18 .08 .12 <.05 ___________________ 3. 8 2.2 1.9 6. 9 11.4 10.5 7.3 8. 7 

FoS•------------------- .04 3.0 5.8 3.0 1. 6 1.4 2. 2 3.4 

SOa-------------------- 0 0 0 13.7 27.7 25.7 0 0 

Total as reported •••• 100.8 98.9 99.9 100.6 100.7 100.8 100.9 99.9 Sb (in ppm) _________ .9 2. 2 2.0 1. 6 .8 .8 ------------------ 1.0 

Specific gravity 

(powder) __ ---------- Specific gravity 2.17 2.32 2.36 2. 52 2. 79 2. 76 2. 50 2.46 

(lump). __ ------- ____ 1. 52 1.30 1. 57 2. 26 2.36 2.41 -M:'OiiiDioiiiion:-- 2. 21 Prominent hydro- Cristoballto, Opal, (pyrite, Opal, pyrite, Alunite, opal, Alunite, (opal, Alunite, Montmorillonthermal minerals.a (anatase, anatase). (marcasite, (pyrite, pyrito>, kaolinite, ite, kaolinite, ite, kaolinite, 

barite). anatase, marcasite, marcasite, (marcasite. (alunite, tillite, 

barite). anatase?). kaolin! te ?) . pyrite). pyrite). marQasite, 

pyrite). 

Granodiorite Granodiorite Andesite dike Andesite dike Granodiorite Granodiorite Granodiorite 

170 217 264 281 335 358 385 

8101------------------------ 61.3 66.9 58.0 54.2 68.6 68.8 69.7 

AhOa----------------------- 12.5 14.6 17.8 FoO •• ---------------------- . 5 .O .16 

FeaOa '·----------·--------- . 0 . 5 MgO·---·------------------ 1. 6 2.0 1. 9 CaO......................... 4. 5 1. 4 2. 2 

17.1 15.4 14.8 15.2 1.2 1. 2 1. 6 .8 .4 .4 . 4 .1 2. 9 1. 8 1.2 1.0 5.0 . 71 2.2 1.6 

Na70----------------------- .40 1.2 .64 1.8 .35 3.6 2.3 

K 10 •••••• ---------------~-- 3. 6 4.1 3. 2 TiOB. ---------------------- . 26 . 30 . 46 

3.0 5.3 3. 9 4.1 . 50. .37 .30 .31 

PaOa----------------·-··--- .06 .07 .20 .36 .07 .06 .07 MnO_______________________ . 25 .13 . 06 . 73 .04 .04 .02 co.________________________ 2. 9 . 07 .18 3.0 <.05 .08 <.05 HtO........................ 8.1 7. 5 13.8 8. 5 5.3 1. 4 4. 4 

FeS•--------------------·--· 3. 7 1. 7 . 77 1.5 . 56 .28 . 41 

803------------------------ 0 0 0 0 0 -------------------- -------------------- 1-------1 Total as reported._ •...• __ 99. 7 100. 0 99. 9 100.2 100.1 98.7 100.0 Sb (in ppm).............. 1. 0 . 7 . 5 -------------------- 2.3 1.0 1.3 

l----------·l--------------l-------~-----l--------------l--------------l·--------------1 Specific gravity ~owder)... 2. 44 2. 52 2. 28 

Specific gravity ump).... .. 2. 30 2. 35 1. 98 

Prominent by< rothermal MoPtmorillonite, Montmorillonite, Montmorillonite, 

minerals.• kaolinite, illite, kllOlinlte, illite, K-feldspar Mn-calcitc, (pyrite). (pyrite, calcite) (pyrite). 

1 Or total Fe as FetOI. I In order of abundance; minor minerals in parentheses. 

REFERENCES 

Slgvaldason, G. E., and White, D. E., 1961, Hydrothermal alteration of rocks in two drill holes at Steamboat Springs, 

Washoe County, Nevada: Art. 331 in U.S. Geol. Survey 

Prof. Paper 424-D, p. Dll~D122 . 

2. 46 2.60 2. 62 2. 53 2. 42 2.16 -2.57 2. 41 Montmorillonite, lllite-montmoril- lllite-montmoril- Illite-montmorilK-feldspa1 (?) lonite, chlorite, lonite, chlorite, lonite, (chlorite, ankerite(?) sericite, (pyrite, calcite). sericite, pyrite). chlorite, (pyrite). (pyrite). 

White, D. E., 1955, Thermal springs and epithermal or deposits, in Bateman, A. M., ed., Economic geology, pt. 1: 

Urbana, Ill., Economic Geology Publishing Co., p. 99-154. 

--- 1957, Thermal waters of volcanic origin: Geol. Soc. 

America Bull., v. 68, p. 1637-1658. 
D118 GEOLOGICAL SURVEY RESEARCH 19 6 2 

154. PRECAMBRIAN GABBRO IN THE CENTRAL FRONT RANGE, COLORADO 

By R. B. TAYLOR and P. IL Snrs, Denver, Colo., and :Minneapolis, ~'linn. 

Precambrian gabbro, a rock type not previously reported from the Front Range of Colorado, has been 

found southwest of Fraser in the Vasquez Mountains 

and west of Apex on the east slope of the Front 

Range (fig. 154.1) . . Though the two areas are 25 

miles apart, the rocks are linked by lithologic similarities and by their age relative to known Precambrian events. The gabbros are characterized by calcic 

plagioclase, orthopyroxene, and clinopyroxene, and 

generally contain some younger amphibole and mica. 

The gabbro plutons were emplaced late in a period of 

deformation and metamorphism in which the older 

rocks of the region attained the sillimanite-almandine 

facies. Contact aureoles have been incompletely metaEXPLANATION 

~ · Strike and dip of 

foliation 

9y 

Strike of vertical 

foliation 

morphosed to the pyroxene hornfels facies. Continuing. regional metamorphism and later local deformation partly retrograded the rocks within the plutons. 

Two lenticular plutons of gabbro have been outlined in the Keyser Creek area southwest of Fraser 

(fig. 154.1). The larger one, the Upson Creek pluton, 

is about 4 miles in length and llj2 miles in maximum 

width. The smaller mass, the Cook Creek pluton, is 

11/2 miles long and almost a mile wide. The bodies 

trend northeastward and have subconcordant, steeply 

dipping contacts that follow the regional trend of the 

gneissic structure in the country rock. Near-vertical 

internal flow structures trending northeast are evident 

in most outcrops. 

N 

0 5 MILES 

KEYSER CREEK AREA 

0 1 MILE 

Geology by R. B. Taylor, 1961 Geology by P. K. Sims end 

P. D. Lowman, Jr., 1958-sQ 

FIGURE 154.1.-Index map and geologic sketch map of gabbro plutons.(patterned areas) in the central Front Range. 

/ 
ARTICLE 154 D119 

The largest body in the Apex area, the Elk Creek 

pluton, is a hook-shaped mass about 2 miles in total 

length and 3J.t of a mile in maximum width that lies 

on the crest of a complex anticline. Several bodies 

less than 1,000 feet in maximum dimension occur near 

this mass. Unlike the bodies southwest of Fraser, 

these ·have a n1assive internal structure. The only 

:folin,ted parts, so far as is known, are lenticular zones 

confined to the eastern side of the Elk Creek pluton 

and are interpreted as protoclastic in origin. 

The gabbroic rocks in both areas are dark gray, 

medium to coarse grained, and generally equigranular. Rare inequigranular felclspathic varieties have 

plagioclase crystals as much as 2 inches in size, and 

melanocratic varieties may have a luster mottling produced by randomly oriented large poikiloblastic hornblende crystals. The composition ranges from melagabbr~ to quartz diorite (see table), but most samples 

are .either gabbro or pyroxene diorite. The U.pson . 

Creek and Cook Creek plutons, because of their characteristic bytownite and bronzite, have affinities with 

ultrabasic rocks (Leake, 1958, p. 159). The rocks of 

the Apex area are less basic, are characterized by intermediate plagioclase, and locally contain substantial 

amounts of quartz. The gabbros tend to weather 

spheroidally to subrounded boulders, to coarse grus or, 

under forest cover, to a distinctive sticky dark-brown 

soil laden with fragments of metamorphic xeaoliths 

and granitic material from crosscutting dikes. 

r:fhe gabbro has a typical hypidiomorphic or· xenomorphic granular texture. The 1narginal phases in the 

Keyser Creek area have a diabasic texture, with 

pyroxene intersertal to plagioclase laths (fig. 154.2A). 

Hornblende surrounds most pyroxene crystals and has 

scalloped contacts against adjoining plagioclase grains. 

Coarser gabbro from the interior of the plutons has a 

strong planar structure defined by flow-oriented plagioclase and pyroxene crystals in a mosaic intergrowth 

(fig. 154.2B). The gabbro of the Apex area is massive and has interlocking plagioclase and pyroxene 

crystals; more rarely, the mafic minerals occur in aggregates with synneusis texture. In both areas gabbro 

varieties much modified by metamorphic retrograding 

are characterized by large ragged grains of replacement amphibole that virtually obliterate the primary 

igneous texture (fig. 154.20). . 

Plagioclase is the dominant mineral in most of the 

gabbro (see table). In the Apex area it is slightly 

zoned calcic andesine or, rarely, labradorite. In the 

Keyser Creek area, it is strongly zoned and ranges 

from about An50 to Ai185 • Simple zoning with calcic 

cores and sodic rims and with growth patterns following crystal faces is characteristic. An irregular pattern is superimposed on many crystals in hornblenderich gabbro; sodic zones follow grain margins and are 

especially wide adjacent to hornblende, and calcic 

plagioclase is confined to remnants of cores or to parts 

adjacent to orthopyroxene crystals. The regular simModes (volmne percent) and mineralogic data for representative samples of gabbroic rocks 

[Localities shown on fig. 154.1, except for 13, 14, and 15; modes from Apex area by D. J. Gable, U.S. Geological Survey] 

Keyser Creek area Apex area 

Upson Creek pluton Cook Creek pluton Elk Creek pluton Scattered bodies 

2 3' 8 9 10 11 12 13 14 15 

--------1--------------------------------

Plagioclase_----____ 70 56 68 50 58 52 35 36 48 71 65 46 9 2 34 

Orthopyroxene______ 8 13 8 20 8 ______ ______ ______ 6 7 1 4 51 43 2 

Clinopyroxene______ <I ______ ______ 6 1 ______ ______ ______ 1 1 6 11 <I 19 

Amphibole_________ 14 19 16 20 27 41 61 58 42 7 11 2 35 28 38 

Biotite_____________ 5 <I 4 3 6 1 3 2 6 6 10 5 6 17 

Magnetite-ilmenite__ <I 11 3 1 1 <I 1 <1 <I 4 4 10 <I 1 4 

Apatite____________ <I <I <I <I <I <I <I <1 <I <I <I <I ______ ______ <I 

Quartz_____________ 1 <I 1 2 2 1 2 2 <I 4 4 13 ______ ______ 5 

Chlorite ____________ ------ <I <I ______ ______ <I <I <1 <I <I 2 _________________ _ 

~~!.~~~~tit~--~--~==================--~~- ~i --~~- ====== ====== ====== ====== --~~- ------ --~~- --~~- ====== ====== Z ?ricit;e_ _ _ _ _ _ _ _ _ _ _ _ < 1 < 1· < 1 .!. _ _ _ _ _ _ _ _ _ _ _ < 1 < 1 < 1 < 1 < 1 ________ :( i _______________ --- _ 

i~~~F~~~~~;;~~ ~~~H ;;;;;; ;;;;;; ;;~;;; ;;~;;~ ~~L ~~:;;; ;;:;;; ;;;~;; ~~~~~ ::::r: ~~ :::::: -=::~~ ~~:t Ph}gioclnse, An 

content __________ 66-82 65-85 6Q-70 72-78 57-68 55-75 5Q-62 5Q-57 55-70 46 46 41 56 54 48 

Orthopyroxene, n>'--- 1. 685 1. 695 1. (i96 1. 696 1. 702 ____________ -----~ 1. 697 __________________ 1. 684 1. 694 _____ _ Amphibole, ny ______ 1. 662 1. 663 1. 663 1. 662 1. 665 1. 654 1. 651 1. 656 1. 663 ________________________ ------ ------
D120 GEOLOGICAL SURVEY RESEAR•CH 19 6 2 

FIGURE 154.2.-Photomicrographs of gabbroic rocks. A, Diabasic gabbro, locality 9, Cook Creek pluton. B, Feldspathic 

gabbro, locality 2, Upson Creek pluton. 0, Hornblende gabbro, locality 7, Cook Creek pluton. All photomicrographs 

are X 20, with crossed nicols. 

pie zoning is interpreted as an igneous feature developed during free growth in a melt. The irregular 

zoning is interpreted as a metamorphic feature developed during amphibolization. 

Both orthopyroxene and clinopyroxene are present 

in most samples. The orthopyroxene is dominantly 

bronzite (NY ranges from 1.684 to 1.702) in subhedral 

crystals that have conspic.uous schiller structure resulting from thin plates of an unidentified brown 

translucent mineral alined parallel to the optic plane. 

Other discontinuous lamellae may be clinopyroxene or 

hornblende. As augite lamellae at a small angle to 

the ( 101) plane in the orthopyroxene were not seen, 

it is inferred that the original form of crystallization 

was orthopyroxene rather than pigeonite. The clinopyroxene is a nearly colorless variety of augite, occurring in subhedral crystals having small oriented inclusions of opaque minerals. With few exceptions the 

clinopyroxene is partially replaced by hornblende that 

follows grain margins or forms a cuneiform intergrowth inside the grain controlled by cleavage. In 

contrast, the orthopyroxene is characteristically rimmed 

by hornblende and retains most of its crystal outline. 

The amphibole in most gabbro samples is a pleochroic dark-green hornblende (NY ranges from 1.662 

to 1.665). Its contacts with other minerals are sharp, 

regular, and usually scalloped. It closely resembles 

the hornblende in the regionally metamorphosed hornblende-plagioclase gneiss. In some samples the plagioclase and clinopyroxene have been partially replaced 

by green hornblende, and the orthopyroxene by a colorless amphibole, perhaps tremolite. In the most 

metamorphosed gabbro a light-blue-green hornblende 

(NY ranges from 1.651 to 1.656) with ragged outlines 

replaces plagioclase and both pyroxenes. It is associated with sodic labradorite, perhaps also a recrystallization mineral, and with minerals of the epidote 

group. 

Black opaque grains, chiefly titaniferous magnetite, 

are locally abundant. In the well-foliated rocks they 

may be flow oriented in part, but in the more massive rocks they appear to be· interstitial to plagioclase 

and pyroxene. Red-brown biotite is variable in 

amount, is closely associated with the other ferromagnesian minerals, and generally occurs along the cleavage of pyroxene 'or hornblende. Quartz is common in 

the gabbroic rocks of the Apex area as anhedral interstitial grains, blebs in other minerals, and in myrmekitic jntergrowths with plagioclase and biotite. 

Other minerals present in small amount are potassium 
ARTICLE 154 D121 

feldspar, allanite, sphene, and apatite (see table). 

Epidote, sericite, calcite, and chlorite oceur in some 

of the n1ore intensely altered rocks. 

Striking contact-metamorphic aureoles have formed 

in the biotite gneisses around the larger intrusions. 

The most intense metamorphism is around the Upson 

Creek pluton, probably because it is larger and more 

basic than the other plutons. Locally, wallrock within 

about 40 feet of the contact has been transformed to a 

breccia of blocky, fist-sized fragments of quartz-rich 

gneiss in a matrix of coarsely crystalline sillimanite, 

cordierite, biotite, plagioclase, garnet, and quartz. 

These minerals apparently grew in the matrix after it 

became snflieiently mobile to flow around pieces of 

more refractory layers. Outside the breccia zone, the 

gneiss has been reeryst.allized to a con.rser grained rock 

with a grn,noblastic texture; n1ore than 300 feet. from 

the contact, half-inch garnets formed in some of the 

layers and inch-long sillimanite prisms in others. The 

chn.racteristie mineral assemblage of the regionally 

metn,morphosed biotite gueisses-quartz-fibrolitic sillimanite-biotite-microline-plagioclase-has been modified 

to a disequilibrium assemblage: quartz-biotite-prismatic. sillimanite-plagioclase-cordierite-garnet-spinelmagnetite. The ma,tted hairlike crystals of fibrolitic 

sillimanite were converted to prismatic sillimanite 

crystals commonly 1-2 mm long, but as much as 21j2 em 

long. The prisms in some places follow old minerallineation directions, but in other plaees have no 

preferred orientation. The greenish-tan to brown biotite of t.he normal gneiss has been partly converted to 

strongly pleochroic orange- to red-brown biotite, and 

partly to corclierite, magnetite, siUimanite, and spinel. 

The cordierite forms small anhedral twinned grains 

with abundant inclusions of magnetite, and is commonly rimmed by aggregates of tiny sillimanite crystals. The gn.rnet is poikiloblastic, and typica1ly contains biotite and magnetite. Tiny rounded blebs of 

spinel occur within cordierite or gn,rnet. llypersthene 

nppears with clinopyroxene in some of the contact 

rocks. These mineralogic changes in the contact 

aureole represent the incomplete adjustme~t of these 

rocks to the pyroxene hornfels facies of contact metamorphism. 

The country rocks adjacent to the Elk Creek pluton 

have been ·recrystallized and sheared. In the contact 

zone the biotite gneisses are coarser grained than similar rocks away from the intrusion. Sillimanitic 

gneisses are changed locally to inequigranular rocks 

containing discoidal aggregates of sillimanite, phlogopitic mica, and green spinel. Biotite-quartz-plagioclase gneiss is locally reconstituted to an orthopyroxene-biotite-quartz-plagioclase rocks with a felted 

texture. At one locality along the east contact, microc1ine-bearing gneiss is sheared to a flaser gneiss and 

bleached for a distance of nearly 50 feet from the contact; quartz forms lens-shaped aggregates with strong 

lineation, and biotite is changed to chlorite. 

The gabbro '"as emplaced during the waning stages 

of the older, major Precambrian deformation recognized in the central part of the Front Range (:1\foench, 

Harrison, and Sims, 1962). The subconcordant contacts of all the masses and the phacolithic form of the 

Elk Creek pluton (fig. 154.1) relate the gabbro to the 

o19,er deformation. The general htck of metamorphic 

structures within the gabbro suggests that it was emplaced too late to have been much deformed by the 

older folding. These interpretations are supported by 

relntions observed in the Upson Creek pluton: This 

pluton is cut by dikes of biotite-muscovite granite 

which are similar to rocks known to predate the second deformation recognized a short distance to the 

north. It cuts small bodies of granodiorite similar in 

structure and composition to the syntectonic Boulder 

Creek Granodiorite of the central Front Range. 

The gabbros of the I\:eyser Creek area were emplaced after the thermal maximum, equivalent to the 

sil1imanite-a1mandine-orthoclase facies, of the older 

Precambrian deformation and metamorphism. A temperahtre difference between the gabbro magma -and the 

country" rocks, which may be estimated as possibly 

more than 500°0, was sufficient to produce extensive 

metamorphism and local melting of the country rock 

and. chifling of the margins of the pluton. After crystallization, green hornblende formed at the expense 

of pyroxene and plagioclase. Wager ( 1932) and Leake 

(1958) point out that hornblende in this quantity in 

basic and ultrabasic rocks is probably the result of 

metamorphism and not of crystallization from a melt. 

Later, during the younger Precambrian deformation, 

light-blue-green amphibole, epidote, and other minerals locally replaced the older minerals. This change 

is most evident in the Cook Creek pluton, which is in 

an area f.tffected by the younger deformation. The 

Upson Creek pluton is less modified and is in an area 

less affected. by the younger folding. The changes 

associated with the younger deformation are attributed to retrograde metamorphism; they parallel 

those described by James (1955) for the transition 

from the staurolite to the biotite zone. 
D122 GEOLOGICAL SURVEY RESEARCH 1 9 6 2 

The gabbro in the Apex area seems to have had a 

more complex history, and formed from a far less 

basis magma. The hornblende, quartz, and potassium 

feldspar may have formed from the interstitial liquid 

late in the crystallization of the magma, or they may 

be metamorphic minerals. The cooling of the magma 

in the environment of regional metamorphism, and the 

succeeding metamorphic history make it nearly impossible to distinguish between igneous, deuteric, and 

metamorphic stages of crystallization. 

REFERENCES 

Leake, B. E., 1958, The Cashel-Lough Wheelaun intrusion, Co. 

Galway: Proc. Roy. Irish Acad., v. 59, B, p. 155-203. 

.Tames, H. L., 1955, Zones of regional metamorphism in the 

Precambrian of northern Michigan: Geol. Soc. America 

Bull., v. 66, p. 1455-1488. 

Moench, R. H., Harrison, J. E., and Sims, P. K., 1962, Precambrian folding in the Idaho Springs-Central City Area, 

Front Range, Colorado: Geol. Soc. America Bull., v. 73, 

p. 35-58. 

Wager, L. R., 1932, Geology of the Roundstone district, Co. 

Galway : Proc. Roy, Irish Acad., v. 41, B, p. 46-72. 

GEOMORPHOLOGY AND GLACIAL GEOLOGY 

155. EROSIONAL FEATURES OF SNOW AVALANCHES, MIDDLE FORK KINGS RIVER, CALIFORNIA 

By GEORGE H. DAvrs, Washington, D.C. 

1Vork do·ne in cooperaUon with the Na,tional Pa-rk Service 

Snow avalanches are one of the principal means by 

which high mountains are. eroded and sculptured. 

They and their effects have been studied extensively 

in Europe, especially in the Alps, where avalanches 

pose a constant threat to life and property. In the 

United States, however, they have received little attention because our high mountains are sparsely inhabited; the damage by snow avalanches is ~ainly to 

highways and railroads. 

Avalanche sculpture is especially well developed 

along the canyon of the Middle Fork of the Kings 

River in the Sierra Nevada, Calif. In parts of the 

canyon not scoured by glaciers, snow avalanches have 

been the dominant. erosional process throughout 

Quaternary time. 

The Middle Fork of the Kings River rises near 

l\{ount Goddard on the crest of the Sierra Nevada and 

flows generally southwestward to its junction with the 

South Fork. The junction is about 10 miles downstream from "Kings Canyon," the popular name for 

the accessible and 'veil-known part of the canyon of 

the South Fork. Most of the drainage basin of the 

Middle Fork is above an altitude of 10,000 feet. The 

l\{iddle Fork flows in a steep-walled canyon, which in 

much of its course has the U-shaped cross section characteristic of glaciated valleys. The canyon is one of 

the deepest and steepest in the Sierra Nevada; in its 

most spectacular reach (fig. 155.1), extending from 

Tehipite Valley upstream 8 miles to Simpson l\{eadow, 

the walls rise 4,000 to 5,000 feet within a mile horizontal distance (fig. 155.2) where they merge with a 

rolling upland surface (fig. 155.3). The physiography 

closely resembles and its geomorphic development 

parallels that of Yosemite Valley, 75 miles northwest, 

which has been so ably described by l\{atthes (1930) 

in his classic paper on the geologic history of Yosemite 

Valley. 

Precipitation in the high parts of the Sierra Nevada 

occurs mainly as snow, between November and May, 

and the water is stored in that form until the late 

spring and early summer melting. Indeed, three 

quarters of the total discharge of the Kings River 

runs off to the San Joaquin Valley between March 1 

and June 30. · At Black cap Basin, altitude 10,300 feet, 

10 miles north of the Middle Fork, the average dept~ 

of snow on April 1st is about 8 feet and its water 

content is 35 inches. · 

Massive granitic rocks of the Sierra Nevada batholith form the floor of most of the drainage basin of 

the Middle Fork although, locally, roof pendants of 

metamorphosed sandstone and siltstone with lesser 

amounts of marble and volcanic rocks have been preserved. Along the walls of the U-shaped canyon upstream from Tehipite Valley, only granitic rocks are 
ARTICLE 155 D123 

FIGURE 155.1.- Topographic map of canyon of the Middle Fork of the Kings River, Calif. Scale: 125,000; contour interval, 

100 feet. Base from U.S. Geol. Survey Topographic Map, Sequoia and Kings Canyon National Parks, Calif. 

FiGURE 155.2.-View northeastw~rd up canyon of the Middle 

Fork of the Kings River, from north wall overlooking 

Tehipite Valley (center foreground). Tehipite Dome, upper left. 

654685 0-62--9 

FIGURE 155.3.-Snow chutes and attenuated rock ribs carved 

by avalanches, south wall of canyon of the Middle Fork of 

the Kings River. Lost Canyon, left foreground. 
Dl24 GEOLOGICAL SURVEY RESEARCH 1 9 6 2 

FIGURE 155.4.-View eastward up face of Windy Peak from 

Simpson Meadow, showing two generations of avalanche 

chutes. Shallow grooves on lower slope represent postglacial avalanche erosion; deep chutes above in unglaciated 

part of canyon are probably Pleistocene. 

exposed. Northeastward-trending vertical master 

joints have determined the profile and orientation o£ 

the sheer cliffs in the steep-walled canyon section. 

Glacial excavation broadened the bottom of the canyon, but triangular facets above the active glacial 

scouring are the site of some of the most impressive 

avalanche sculpture. 

Avalanche sculpture is especially well developed 

along the southeast wall of the canyon of the Middle 

Fork of the Kings River between Tehipite Valley and 

Lost Canyon. Here many of the cliffs have a fluted 

surface, on which straight smooth gullies alternate 

with rock ribs (fig. 155.3). Matthes (1938) applied 

the name "snow chutes" to similar features in the 

Mount Whitney area. The chutes have a hyperbolic 

cross section and, where closely spaced as on figure 

155.3, the dividing ridges are attenuated ribs that rise 

200 feet or more above the flanking chutes. In some 

places the ribs have been broken to form rows o£ 

separate spires. 

The snow chutes commonly are wider at the upper 

end than at the lower end. In many places several 

chutes on the upper walls of the canyon join to form 

a single chute downslope. Matthes (1938) noted that 

most chutes terminate at the upper limit of glacial 

scouring, and this is generally true also in the canyon 

of the Middle Fork. He concluded from this that virtually all the chute sculpturing took place in Pleistocene time. However, at Windy Peak (fig. 155.1) two 

generations o£ chutes can be seen, as shown in figure 

155.4: an upper set of deep chutes above the glaciated 

zone, and numerous shallow chutes on the lower slopes 

that evidently have formed since the last glacial retreat. 

Matthes ascribed the chutes to abrasion by snow 

and entrained rock debris. Windblown snow accumulates at the top of the cliff in the form of a massive 

cornice; sudden breaking of the cornice initiates a 

snow avalanche. Rock fragments and granules made 

available by exfoliation of the granitic rocks provide 

the abrasive action. In the Kings River area, small 

amounts of talus were poised ready for sliding in 

some chutes, but most chutes contained little debris 

and only small bodies of talus debris abutted the toes 

of the cliffs. These observations suggest that the 

movement of rock debris is a minor factor in the 

formation of avalanche chutes. 

Erosional features of avalanche origin of a different 

sort are avalanche scour pits, a good example of which 

can be seen on the floor of Grouse Meadow on Blue 

FIGURE 155.5.-View westward across Grouse Meadow and Blue 

Canyon Creek, showing avalanche scour pit, upper center. 

Pond (shown by arrow) is about 60 by 25 feet. 
~. 

'I 

ARTICLE 156 D125 

Canyon Creek (fig. !"55.5). Grouse Meadow is a nearly 

level alluviated valley at an altitude of 8,500 feet, 

about 3 miles upstream from the confluence of Blue 

Canyon Creek and the Middle Fork of the Kings 

Rive1~. Just to the west, l(ettle Ridge rises to 10,500 

feet in 0.7 mile. At the foot of l(ettle Ridge, on a 

gentle rise on the floor of Grouse l\ieadow, is a natural 

pond about 60 feet long by 25 feet wide and 8 to 10 

feet deep, looking very much like a swimming pool. 

The depression is ·enclosed at its down valley end by an 

embankment of rock and soil which appears almost 

to have been pushed up by a bulldozer. The location 

of the pond at the foot of l(ettle Ridge and the large 

boulders scattered around the rim suggest avalanche 

origin, and the pit containing the pond is interpreted 

as an avalanche scar. Presumably, a snow avalanche 

tumbled down the mountain and shoved the soil outward and forward to form a rim; then the snow 

melted and left behind a depression filled with water. 

Spring flow from the slope above keeps the pond 

almost brimfull, and discharge is mainly by seepage 

through the banks. 

REFERENCES 

Matthes, F. E., 1930, Geologic history of the Yosemite Valley: 

U.S. Geol. Survey Prof. Paper 160. 

-- 1938, Avalanche sculpture in the Sierra Nevada of 

California: Internat. Assoc. Hydrology Bull. 23, p. 631-

637. 

156. CONFIGURATION OF THE BEDROCK BENEATH THE CHANNEL OF THE LOWER MERRIMACK 

RIVER, MASSACHUSETTS 

By EowAno A .. SAMl\IEL, Boston, l\iass. 

lVo·r1.: done in cooperation with the Jlfassachnsetts Depa.rtwent of Pu.blic Works 

Geologic mapping and previous seismic investigations in northeastern l\iassachusetts have disclosed the 

existence of buried bedrock valleys whi~h presumably represent the traces of a preglacial drainage pattern and are the site of highly productive waterbearing deposits (Baker, Healy, and Hackett, 1961). 

This article reports further data on the configuration 

of bedrock in the·lower Merrimack River valley obtained recently during an investigation of groundwater resources in the valley. The current investigation indicates that the bedrock surface below the river 

channel is shallow in much of the reach downstream 

from :Haverhill, although depths of more than 100 feet 

were noted at places. 

A seismic profile was made during September 1961 

in portions of the Merrimack River channel along a 

20-mile reach between Haverhill and the mouth of the 

river, near Plum Island, l\iass. (fig. 156.1). The area 

is included in the Haverhill, Newburyport West, and 

Newburyport East 7¥2.-minute topographic quadrangles of the Geological Survey. The methods used 

in making the profile were standard reflection techniques, employing a broad-band penetrating echo 

sounder installed in a 40-foot launch. The fieldwork 

was done under contract by Alpine Geophysical Associates, Inc., of Norwood, N.J., and the seismic records 

were interpreted by Hartley Hoskins of the Woods 

Hole Oceanographic Institution. 

The seismic signal was produced by a repeating 

underwater spark source towed about 50 feet behind 

the boat at a speed of about 3 knots. Reflected signals 

were received in a transducer, also towed 50 feet behind the boat and about 3 feet beneath the surf{tce of 

the water. The amplified signal from the transducer 

was continuously recorded on electrosensitized paper 

by a standard recording instrument. Hoskins and 

Knott (1961) give· a detailed description of the g(meral method and types of instruments. used. 

Bedrock reflections were generally well defined in 

the eastern half of the traverse except in outcrop 

areas where the bedrock surface was at shallow depths 

that approximated the median wavelength of the seismic signal. East of Newburyport, bedrock deeps overlain by horizontally bedded . sediments were clearly 
D126 GEOLOGICAL SURVEY RESEAR•CH 19 6 2 

N 

I 

EXPLANATION .. . • . 

Contact 

Bedrock • exposure 

__ 5 ...__ 

Trace of seismic profile along 

river channel Numbers represent miles above mouth 

0 

.n 

Test boring reaching bedrock 

Number is altitude of bedrock surface, in feet below mean sea 

level 

05 

Test boring completed in 

overburden 

Number is depth qf refusal; in 

feet below mean sea level 

2 MILES 

MAP SCALE 

BEDROCK PROFILES 

"'"'.l..i:"~ ~~~ .... ;e.,··. : 1'~0 0' ' 

11(1 ~..:···· f"w -. 100 

y / 200' 

8 7 

I. 

18 17 16 15 14 13 12 11 ,. 10 I I I 1 · ~ ·a · - ·~~~-~ .. -~ r:~: Shaded area indicates fill above bedrock 

VERTICAL SCALE IS IN FEET; HORIZONTAL SCALE IS IN MILES 

DATUM IS MEAN SEA LEVEL 

FIGURE 156.1.-Bedrock profile beneath the channel of the lower Merrimack River, Mass., made with a continuous seismic reflection 

profiler. Plan view shows geology (Clapp, 1921) and bedrock altitudes .from test borings. 

shown; depths greater than 100 feet were found between miles 1 and 2, 4 and 5, and 6 and 7 (fig. 156.1) . 

The seismic record was generally unsatisfactory in 

the reach between Rocks Village and Haverhill. In 

most of this reach continuous reflections were not 

received from bedrock, although at a few points near 

miles 14 and 15 reflections were recorded that indicated bedrock depths on the order of 200 feet. The 

instrument used was not suitable for recording signals from depths greater than 200 feet, therefore it 

is possible that bedrock was more than 200 feet deep 

in most of the 6-mile reach upstream from R9cks Village. A more reasonable explanation for the lack of 

bedrock signals, however, is that the bedrock is at a 

depth of less than 200 feet, but tlfat the seismic reflections were attenuated due to the lithologic character of the fill or the nature of the bedrock contact. 

Test borings made along the bank of the Merrimack 

River upstream from Rocks Village during the spring 

of 1962 indicate that the fill consists chiefly of gravelly 

material, in contrast to clay, silt, and fine sand in the 

downstream reach. The borings, which were carried 

to bedrock or to refusal, suggest that the bedrock 

surface is less than 200 feet below sea level in the 

questionable reach. Bedrock was found near 40 feet 

below sea level above mile 19, at about 60 feet near 

mile 16, and at 35 feet at mile 15. The deepest points 

confirmed .. by borings were below 76 feet below sea 

-. 
ARTICLE 157 D127 

level just upstream from Rocks Village and below 77 

feet between miles 16 and 17. 

The geologic implications of the seismic records remain to be clarified by further mapping, seismic exploration, and test drilling. In particular, further 

work will be needed to relate the configuration of the 

bedrock surface to the history of glacial deposition in 

the region. 

REFERENCES 

Baker, J. A., Healy, H. G., and Hackett, 0. M., 1961, Groundwater conditions in the Wilmington-Reading Area, Massachusetts: U.S. Geol. Survey open-file report, 162 p. 

Clapp, C. H., 1921, Geology of the igneous rocks of Essex 

County, Massachusetts: U.S. Geol. Survey Bull. 704, 132 p. 

Hoskins, Hartley, and Knott, S. '.r., 1961, Geophysical investigation of Cape Cod Bay, Massachusetts, using the continuous seismic profiler: Jour. Geology, v. 69, no. 3, p. 330-340. 

157. GEOLOGY OF PLEISTOCENE DEPOSITS OF LAKE COUNT'Y, INDIANA 

By J. S. RosENSHEIN, Indianapolis, Ind. 

Work done in coope-ration with the Division of Water Resources, Indiana Department of Conservation 

Evaluation of subsurface geologic data, collected 

as part of a ground-water investigation in northwestern Indiana, has led to a tentative differentiation of 

the glacial drift underlying L~ke County, Ind. (fig. 

157.1) into four distinctive lithologic units. These 

units are economically significant to the county as they 

serve as important sources of water supply. The lithologic units range in age from early Pleistocene to 

Recent and locally form a stratigraphic sequence more 

than 250 feet thick. They extend eastward and westward into adjacent counties in Indiana and Illinois. 

The subsurface geology of the units provides additional facts that may lead to a more comprehensive 

interpretation of the glacial history of the county. 

This history to date is based chiefly on interpretation 

of surface expression of deposits as described by 

Leverett and Taylor ( 1915), Wayne ( 1956, 1958), 

Zumberge (1960), and R. J. Vig (written communication, 1959). 

The distribution and relationship of each unit are 

shown in the generalized sections on figure 157.2. 

The location of these sections is shown in figure 157.1. 

The oldest lithologic unit, tentatively designated unit 

4, underlies about 500 square miles of the county and 

consists chiefly of till that is a gray to bluish-gray 

pebbly, sandy, silty clay, locally hard and compact. 

It ranges in thickness from 0 to more than 150 feet 

and in age from early Pleistocene to Illinoian. The 

till represents drift deposited during at least the Kansan and Illinoian Glaciations. The unit contains sev-

~~~~~J-j ~~------~------~--~N. 

A'H-----~~--r-,_~. 

rn!< 

..... z 

0 z l< ..... ~ 0-------++----___,_--f------f ;.:l•Z 

........... 

)!-+-----+--+--~ I 

COUNTY 

T. 

, 32 

,../' N. 

/ R. 7 W. 0 6 MILES L-...1..--L-..L.-L......I...--' 

t-t------==--...::-------1~ ,--' R. 8 W. 

R.IOW. R. 9W. 

FIGURE 157.1.-Index map showing lines of sections (fig. 157.2), 

Lake County. 
D128 GEOLOGICAL SURVEY RESEAHCH 1 9 6 2 

8oo'A A' EXPLANATION 

700' Unit 1 

Glaciolacustrine sand 

600' ~ ~ 

~ 

>- ~ Unit 2 0:: 

.s Clay till with intertill ex: 

z 

~ sand and gravel 0:: 

LIJ 

rg 1-

~ ex: 

;:::) 

~ Unit3 . 0 .,., 

~ 

500' 

6:; Glaciofluvial sand 

800' B C-C' B' 

700' Unit4 

Clay till 

~ } z z c( c( 

Bedrock a:oz 

:::>ZO 

Chiefly dolomite and ....Jcx:> 

- LIJ dolomitic limestone (/') 0 

600' 

500' 

800' c D-D' A-A' C' 

700' 

600' 

500' 

800' D. A-A' C-C' D' 

700' 

600' 

500' 

0 2 3 4 5 MILES 

VERTICAL EXAGGERATION X 52.8 

DATUM IS MEAN SEA LEVEL 

FIGURE 157.2.-Generalized sections showing lithologic units in glacial drift of Lake County. 

eral relatively thin discontinuous sand or gravel zones 

that may represent intervals between these glaciations. 

The till mantles the bedrock almost everywhere in the 

county, except locally where the unit has been removed 

by postdepositional erosion, and it rests disconformably upon rocks of Silurian, Devonian, and Mississippian ( ? ) ages. Locally in the northern part of the 

county the basal part of the unit consists of relatively 

thin sand or gravel. This sand or gravel partly fills 

the deeper parts of several preglacial valleys whose 

streams flowed northeastward toward the area underlying Lake Michigan. 

Unit 4 is overlain disconformably in the southern 

two-thirds of the county by an extensive glaciofluvial 

deposit, tentatively designated unit 3, that is primarily 

of Illinoian age. Unit 3 consists chiefly of sand with 

some interbeds of sand and gravel, and very locally of 

thick clay. The unit ranges in thickness from 0 to 

100 feet and underlies about 370 square miles of the 

county.· It is thickest along its northern edge (fig. 

-. 
I I 

ARTICLE 157 D129 

157.2, sections A-A' and D-D') and in the western 

part of the county (fig. 157.2, ·sections A-A' through 

D-D') where locally it thickens toward Illinois (fig. 

157.2, section B-B'). Postdepositional erosion has removed part of the unit in the western half of the 

county. The erosion accounts for the marked thickening and thinning of the unit here in relatively short 

lrrteral dista.nces. This erosion took place during 

Sangamon time when several interglacial streams, 

which flowed northward and westward into Illinois, 

cut deeply into the unit. 

The former stream system has somewhat influenced 

the topography of the present land surface. Several 

lakes occupy elongate depressions that coincide with 

these Sangamon interglacial valleys. 

In the broad sancJ.y plain in the southern quarter of 

the county, unit 3 grades upward into glaciofluvial 

and associated windblown sand that ranges in age 

from late Wisconsin to Recent. This younger sand, 

generally less than 10 feet thick, forms the ·upper part 

of unit 3. It is somewhat silty and clayey and is 

locally interbedded with layers of organically rich silt 

and clay of relatively small areal extent. 

Unit 3 is overlain by a mantle of till that extends to 

the surface and forms the terminal and ground 

moraines of the Valparaiso morainic system. This 

surface expression is somewhat influenced by the topography of the underlying deposits of pre-Wisconsin 

age. The till, tentatively designated as unit 2, ranges 

in thiclo1ess from 0 to about 100 feet and in age from 

early to late Wisconsin. The unit underlies about 300 

square miles in the central three-quarters of the county. 

It consists of a lower till member of early ( ~) 'Visconsin age, a relatively thin intertill sand and gravel 

member, and an upper till member of late Wisconsin 

age. This sequence in part has been recognized by 

R. J. Vig (written communication, 1959). The lower 

till member is gray to bluish-gray pebbly, sandy clay 

that is locally hard. It ranges in thickness from 0 

to about 80 feet, and contains discontinuous lenses of 

sand and gravel of small areal extent. The lower till 

member is overlain by a relatively thin sand and 

gravel member that is not present throughout the 

county but where present separates the upper till 

member from the lower till member. The upper till 

member is buff, yellow, or brown somewhat sandy, 

silty clay that ranges in thickness from. 0 to about 60 

feet and is late Wisconsin in age. This till is exposed 

at the surface in many parts of the county and comprises the surface material of the Valparaiso morainic 

system. 

Unit 2 is overlain along its northern edge by glaciolacustrine sand, silt, and clay, that is herein tentatively designated unit 1. Unit 1 consists chiefly of 

fine to medium sand that is interbedded with zones of 

beach gravel, silt, and clay, all of which are locally 

organically rich. Along the eastern edge of the county 

. the unit consists of alternating layers of thinly laminated silt and clay as much as 30 feet thick. Unit 1 

was deposited on units 2 and 4 upon a surface that 

sloped gently, about 10 feet per mile, toward Lake 

l\1ichigan. 

Unit 1 ranges in thickness from 0 to about 70 feet. 

It underlies. about 140 square miles of the county. 

The deposit is of late V\Tisconsin to Recent age and 

marks the transition period in the glacia1 history of 

Lake County between the formation of glacial Lake 

Chicago and the formation of Lake l\1ichigan. 

REFERENCES 

Leverett, Frank, and Taylor, F. B., 1915, The Pleistocene of 

Indiana and Michigan and the history of the Great Lakes: 

U.S. Geol. Survey Mon. 53, 529 p. 

Rosenshein, J. S., 1961, Ground-water resources of northwestern Indiana, preliminary report-Lake County: Indiana 

Dept. Conserv., Div. Water Resources Bull. 10, 229 p. 

Wayne, W. J., 1956, Thickness of drift and bedrock physiography of Indiana north of the Wisconsin glacial boundary: Indiana Dept. Conserv., Geol. Survey Prog. Rept. 7, 

70 p. 

-- 1958, Glacial geology of Indiana: Indiana Dept. Conserv., Geol. Survey Atlas Mineral Resources Map 10. 

Zumberge, J. H., 1960, Correlation of Wisc,Jnsin drifts in Illinois, Indiana, Michigan, and Ohio: Geol. Soc. America 

Bull., v. 71, no. 8, p. 1,177-1,188. 
D130 GEOLOGICAL SURVEY RESEARCH 19 6 2 

158. GEOLOGY OF THE VERMILION END MORAINE, NETT LAKE INDIAN RESERVATION, MINNESOTA 

By RALPH F. N ORVITCH, St. Paul, ~finn. 

Work done in cooperat·ion with the U.S. Departm.ent of Healf.h, Education, and Welfare 

Recent geologic mapping of glacial deposits on the 

Nett Lake Indian Reservation, 35 miles south of 

Rainy Lake in northernmost Minnesota, indicates 

that the St. Louis sublobe of the l{eewatin ice sheet 

did not completely override the Vermilion end moraine as previously supposed, ·and that wave erosion 

by glacial Lake Agassiz locally washed out and reworked parts o:f the Vermilion moraine. 

The segment of the Vermilion end moraine that 

traverses the Nett Lake Indian Reservation :forms a· 

prominent ridge where it crosses the eastern boundary 

of the reservation at an altitude of more than 1,500 

feet; it reaches a peak altitude greater than 1,550 feet 

in sees. 1 and 2, T. 64 N., R. 22 ,V. From this peak 

it diminishes in altitude westward and merges with 

the surrounding lake plain at an altitude of about 

1 350 feet in the west-central part of the reservation. 

End-moraine deposits are missing in a gap about 31j2 

miles wide in the southeastern part of T. 65 N., R. 23 

,V. Evidently, the moraine was eroded away by wave 

action of glacial Lake Agassiz at the 1,360-foot stage. 

The moraine can be traced northwestward from sec. 

16, T. 65 N., R. 23 vV., where it forms a subdued ridge 

trending northwestward to the boundary of the reservation (see fig. 158.1). 

The Vermilion end moraine was probably formed 

during a readvance of the Rainy ice lobe in late Cary 

time (Wright, 1956, p. 19). Immediately south of 

the shallow body of water forming Nett Lake, the 

highest part of the moraine consists largely of sand 

and some gravel but contains many huge boulders 

derived from local bedrock. Except for their erratic 

positions many of the boulders might be interpreted 

as bedrock outcrops. Although drill-hole evidence is 

EXPLANATION 

EJJ 

Beaeh deposits 

Clrit!fl• eatld, eoollo(u gt"BWl atld IICGtUNd botddn-8 

High outwash deposits 

.vo.tl• ....u-..-f __,....., ~ fi- to coaree gt"Bvel 

EDd-mon.iDe depollit 

Mo•tl• eatld•, ~ till (Rai•• dr\fl), ht itteltulea 

t!Gb,._ till (St. Loo.ia dr\fl) i• tle -•t.lrtl pclrt 

of Verwriliotl tiiM'GiM 

~ } ~ 

Granite Loe~ ioodeMiu -pped JIClfcMa of till 

.. Local exposure of argillite, graywacke, and metamorphosed volcanic rocks (Knife Lake Group) 

Contact 

>-

a: 

c( 

z 

a: 

UJ 

Icc 

::I 

0 

Base ·from general highway map 

series of Minnesota. Geology 

transferred from unadjusted 

aerial photosraphs 

GeoiQ8Y by Ralph F. Norvitcl), 1961 AU COfttacta approzi.-ta and it~Urpretcd 

j'r&M urial pllotoqraplu 

0 2 3 4 MILES o X Kame Gravel pit 

FIGURE 158.1.-Surficial geology of the Nett Lake Indian Reservation. 

..,, 
, ... 

ARTICLE 15 8 D131 

Surficial deposits of the Nett Lake Indian Reservation, Minn. 

d 

~ ..0 I g Cl) Unit Description Topographic situation 

rz:l 

e Cl) Q. ~ ~ rz:l 0 C£l 

-- Swamp and lacus- Swamp deposits consist of silty clay and Covers most of low-lying area. Allu-

...:> trine deposits peat, range in th_ickness from 0 to 7 feet, vial deposits are along Little Fork d and alluvium. cap laustrine clay and St. Louis till. River. Q;) 

I:) Alluvial deposits consist of sand and silt. Q;) 

~ - Beach deposits Mainly well-sorted sand but contain some Sandy slopes near Vermilion moraine. 

boulders. Formed along shore of glacial 

>. Lake Agassiz at 1,360-foot stage. I:) 

·a ~ d .s St. Louis drift Mostly gray to buff pebbly calcareous clay Thinly mantles western part of Ver- lSI 

""' cCS 0 Q;) ~ till that contains abundant shale and milion moraine up to 1,400 feet and d ...:> d Q;) cCS limestone pebbles. Till has been washed occurs as isolated patches of ground 0 ::s c::l 

a Q;) ~ by a glacial lake in low areas. moraine in low areas. 

d d Q;) 

I:) ·oo High outwash Mostly medium-grained sand veneered by Flanks southern margin of Vermilion d 0 

...:> 0 gravel, presumably deposited in front of moraine in southeastern part of I:) 

.~ Q;) .~ >. Vermilion moraine. reservation above 1,400 feet altip:: ~ tude. ""' cCS 

0 Rainy drift Sandy, bouldery till; includes fragments of Forms Vermilion moraine. Altitude 

metamorphic, igneous, and sedimentary ranges from 1,350 to 1,550 feet. 

rocks. 

I Knife Lake Dark dense argillite, slate, and granite. Forms isolated knobs near Vermilion 

8 d Group. moraine and low ridges in north- cesces 

~:;~ .... Cl:l""' 

... .o ~ 

not available, the prominence of the morainal ridge 

in this vicinity is interpreted as the result of accumulation on a bedrock high. 

According to Leverett ( 1932, p.- 56), the Vermilion 

end moraine in this area was thinly coated by drift 

deposited by the St. Louis sublobe of the Keewatin 

ice sheet in Mankato time. ..However, the author was 

not able to find St. Louis drift above an altitude of 

1,400 feet on the Vermilion moraine.- The drift of the 

St. Louis sublobe contains abundant limestone and 

shale pebbles, whereas drift of the Rainy lobe, which 

forms the bulk of the Vermilion end moraine, contains some limestone pebbles but no shale. The Rainy 

drift is predominantly a sandy, bouldery till derived 

from coarsely crystalline igneous rocks, whereas the 

St. Louis drift consists largely of gray (bu·ff where 

oxidized) pebbly calcareous lake-washed clay till.· A 

high kame in the NWlJ.i, sec. 3, T. 64 N., R. 22 W., 

consisting mostly of Rainy lobe material and containing limestone but no shale, occurs at an altitude of 

nearly 1,450 feet. In contrast, a lower· kame at about 

1,400 feet, in the SWlJ.J, sec. 34, T. 65 N., R. 21 W., 

about a quarter of a mile east of the reservation 

boundary, contains a high percentage of limestone 

and shale pebbles definitely deposited by the St. Louis 

sublobe. The absence of shale fragments above 1,400 

feet suggests that St. Louis sublobe drift was not deeastern part of reservation. 

posited above this altitude. Although overriding of 

the western part of the Vermilion moraine in the Nett 

Lake area by ice of the St. Louis sublobe probably 

contributed, in part, to subsequent oerosion of that part 

of the moraine by lake washing, the St. Louis sublobe 

probably did not override the Vermilion moraine in 

the central and eastern parts of the area. 

The number and size of the boulders in the Vermilion end moraine decrease eastward and westward 

from the highest part of the moraine. Many boulders 

lie on the surface as if deposited from ice rafts; however, they are alined parallel to the trend of the end 

moraine and lie at different altitudes. Boulders probably were concentrated in the gap, where the Vermilion moraine is missing, by removal of the finer materials of the moraine deposits by wave action of glacial 

Lake Agassiz. The lake covered a Jarge part of the 

Nett Lake Reservation up to altitudes of nearly 1,360 

feet (Leverett, p. 133 and pl. 1). Leverett refers to 

a higher beach encircling the. prominent ridge south 

of Nett Lake, but the author was unable to find evidence of a higher beach. A high-level deposit of outwash, which might be interpreted as beach material, 

occurs above a 1,400-foot altitude immediately south 

of the Vermilion end moraine in the eastern half of 

the area. Although the central part of this body of 

outwash consists largely of medium sand, it probably 
·nt32 GEOLOGICAL SURVEY RESEARCH 1 9 6 2 

was not deposited by Lake Agassiz because it is at an 

altitude of 1,400 feet, well above any known Lake 

Agassiz shoreline. The age of this high-level outwash 

deposit is probably late Cary, the same as that of the 

Vermilion moraine. 

Further evidence that the moraine has been lake 

washed is an extensive body of lake or beach sand 

in the west-central part of the area presumably derived f~om reworking of morainal deposits in the area 

now occupied by the gap. A less extensive body of 

lacustrine sand flanks the outwash. deposit south of 

the eastern part of the Vermilion moraine. Apparently the lake surface was not high enough to erode 

the sand from the outwash. 

REFERENCES 

Leverett, Frank, 1932, Quaternary geology of Minnesota and 

parts of adjacent States; U.S. Geol. Survey Prof. Paper 

161, 149 p., 5 pl. 

Wright, H. E., Jr., 1956, Sequence of glaciation in eastern 

Minnesota, field trip no. 3, in Geol. Soc. America Guidebook Series: Minneapolis meeting, p. 1-24. 

159. THREE PRE-BULL LAKE TILLS IN THE WIND RIVER MOUNTAINS, WYOMING 

By GERALD M. RICHMOND, Denver, Colo. 

The sequence of Pleistocene glaciations in the Wind 

River Mountains of Wyoming as defined by Blackwelder ( 1915) consisted of three "glacial stages," from 

oldest to youngest, the Buffalo, Bull Lake, and Pinedale. Because of the cla.rity of Blackwelder's original descript.ions, these units, here called glaciations in 

conformity with the code of the American Commission on Stratigraphic Nomenclature (19.61), have long 

served a$ a standard sequence for correlation in Wyoming (Fryxell, 1930, Bradley, 1936; Horberg, 1940) 

and the terms Bull Lake and Pinedale are receiving 

increasing recognition as such throughout the Rocky 

Mountain region (Horberg, 1954; Richmond, 1954, 

1960a). Some subdivision of the units has resulted 

from later studies and it is the purpose of this article 

to show that, at least locally, three glaciations are. 

represented by deposits called the Buffalo Till. 

Deposits of the younger glaciations may be briefly 

summarized. Those of the Pinedale Glaciations include three sets of moraines and related outwash terraces (Richmond, 1948; Holmes, 1951; Holmes and 

Moss, 1955) on the basis of which an early, a middle, 

and a late stade· of the Pinedale Glaciation have been 

inferred (Richmond, 1960a, 1960b, 1961). In some 

areas, a humic or weakly oxidized soil stratigraphically separates deposits of the early and middle stades. 

Deposits of the Bull Lake Glaciation include two 

sets of moraines and associated outwash terraces on 

the basis of which an early and a late stade of the 

Bull Lake Glaciation have been inferred, (Fryxell, 

1930; Richmond, 1948, 1960a; Holmes, 1951; Blackwelder, 1950; Holmes and Moss, 1955). The fact that 

in the La Sal Mountains, Utah, and in Glacier National Park, Mont., a maturely developed zonal soil 

stratigraphically separates deposits of the early stade 

from those of the late (Richmond, 1960a) , and that 

near desiccation of Lake Bonneville occurred during 

the soil-forming interval (Morrison, 1961; Richmond, 

1961) suggests that the two stades represent two distinct glaciations. • 

Deposits called Buffalo Till in the Wind River 

· Mountains tend to lie above or beyond the outer limits of younger tills. Some are extensive, but others 

are small patches or merely a zone of erratic boulders. Most are sheetlike deposits capping interstream 

divides, 200 to more than 1,000 feet above trunk 

streams, which has led many writers to conclude that 

they are older than the canyons. However, the fact 

that some deposits of the Buffalo Till occur at or 

near stream level and are separated from the deposits 

on the divides by erosion of the canyons (Holmes and 

l\1oss, 1955; Richmond, 1957) suggests, as Blackwelder 

( 1915) thought possible, that the Buffalo Till may 

represent more than one glaciation. 

In general, the deposits lack morainal form, but 

some, especially those in the valleys, display large, 

smooth, mature moraines. Along the mountain front, 

the till is related to 2 and in places 3 outwash gravel 

terraces, a further suggestion of multiple glaciation. 

•. 
ARTICLE 159 D133 

The till is commonly compact and consists of unsorted and unsized angular to subangular pebbles to 

houlders in a sandy to silty arkosic matrix. It contains more silt and clay than do younger tills. The 

contained rock fragments are ·mostly crystalline, both 

fresh and decomposed. The granite weathering ratio, 

according to Blackwelder (1931), is 0-30-70. However, the writer believes that most of the rotted materinJ, including the arkosic grus in the matrix, is 

derived secondarily either from deeply rotted crystalline rocks underlying the high Tertiary erosion surfaces of the range, or from the abundant deeply decomposed· crystalline boulders in conglomerate of 

Tertiary age that flanks the range. 

Surface exposures of the till are commonly weathered to a thick very strongly developed soil. In its 

pedalfer facies, the upper part of the B horizon of 

the soil is a reddish (2.5Y R-1 .5Y R) residual leached 

clay .in which most crystalline rocks tend to be deeply 

decomposed. The lm'1er part of the B horizon is similar but yellowish brown (7.5Y R-10Y R) and contains 

less altered rock. In the pedocal facies of the soil, 

the B horizon rests on a thick Cca horizon intensively 

enriched in calcium carbonate. These soils, however, 

are commonly so stripped by erosion that only the' 

lower part of the B horizon or merely remnants of 

the Cca horizon are preserved. 

Superimposed tills, included in deposits called the 

Buffalo Till (Blackwelder, 1915), were fOtind by the 

writer on the northeast flank of the 'Vind River 

l\'[ountains at Bull Lake and at Dinwoody Lake (fig. 

159.1). On the north side of Bull Lake, the escarp-

.ment of Cedar Ridge exposes three lithologically distinct tills, separated by disconformities and, locally, 

by the eroded remnants of soils. The deposits are 

R. 4 W. 

T. 

)\ R. 2 W. 

10 T. 

J~ 4 

N. 

<~ 

r T. 

3 

~ N. 

1-.A T. 

\ ,,... 2 

~ N. 

\ 109° 

( 0 5 MILES L...----J 

FIOURE 159.1.-Sketch map showing location of Bull 

Lake n.nd Dinwoody Lake, on the northeast side of 

the \Vinci River Mountains, and location of stratigrnphic sections described in text. 

FIGURE· 159.2.-Part of the south side of 

Cedar Ridge at Bull Lake. BLT, Bull 

Lake Till (30-40 ft thick); DLT, Dinwoody Lake Till (60-70 ft thick); SRT, 

Sacagawea Ridge Till (20ft thick); CRT, 

Cedar Ridge Till ( 40-50 ft thick); Tg, 

conglomerate of Tertiary age. 

overlain disconformably by the Bull Lake Till, here 

in its type area, and rest on an erosion surface cut 

acros~ gently tilted conglomerate of Tertiary age 

(fig. 159.2). On the north side of Upper Dinwoody 

Lake, in the escarpment of Sacagawea Ridge, the 

middle and upper of the three tills are also exposed 

beneath the Bull Lake Till and above the conglomerate of Tertiary age. The conspicuous lithologic characteristics of the tills assure correlation between the 

two localities. Detailed stratigraphic sections of these 

exposures are given bel ow. 

The oldest of the three tills is here named the Cedar 

Ridge Till from Cedar Ridge on the north side of 

Bull Lake. The middle till is named the Sacagawea 

Till from Sacaga wea Ridge on the north side of 

Upper Dinwoody Lake, and the youngest till is named 

the Dinwoody Lake Till. 

No specific correlation of any one of the three tills 

could be established with the Buffalo Till in its type 

area on the North Fork of the Snake River (Blackwelder, 1915) where, unfortunately, the overlying 

Bull Lake Till is so extensive that typical deposits 

of the Buffalo Ti11 are rarely exposed. 

Section in the escarpment of Cedar Ridge on the north s1:de of Bull 

Lake, center sec. 31, T. 3 N., R. 3 W. 

[Locality 1, fig. 159.11 

Pinedale Till: 

Stripped surface soil, light-brown (7 .5 Y R 4/4); loose 

stony, silty fine sand; thin calcareous coatings on stones ________________________________________ _ 

Till, light-gray (10YR 7/2); loose, stony, silty sand. 

Stones subangular to angular, range from pebbles to 

boulders, a few soled, faceted, or striated; most of 

fresh crystalline rock, but some of sedimentary rock. 

mostly limestone __ .. ________________________ ----.. 

Disconformity. 

Thickness 

(feet) 

1-2 

15-20 
D134 GEOLOGICAL SURVEY RESEARCH 19 6 2 

Section in the esca·rpment of Cedar Ridge on the north side of 

Bu.ll Lake, oenter sec. 31, T. 3 N., R. 3 W.-Continued 

[Locality 1, fig. 159.1) 

Bull Lake Till: 

Till, brown (7.5YR 4/4-6/4) to light-olive-brown (2.5Y 

5/4); compact, stony, silty sand. Resembles Pinedale Till except in color, hardness, and weathering, 

and has more large boulders _____________________ _ 

Disconformity. 

Din woody Lake Till: 

Till, light-brown (7.5YR 6/4) to light-yellowish-brown 

(10YR 6/4); compact, massive, stony silty sand, very 

bouldery. Matrix has distinctive pinkish hue owing 

to silt derived from Mesozoic red beds. A few stones 

soled, faceted, or striated. About half of rock matterial crystalline, about half sedimentary. Layers of 

pinkish bedded siit. and local lenses of angular gravel and sand at base _______________________________ _ 

Disconformity. 

Sacagawea Ridge Till: 

Stripped B horizon of soil, reddish-brown (5YR 5/4); 

compact, stony, sandy, clayey silt; structureless. 

Till, pale-:brown (IOYR 6/3) to light-yellowish-brown 

(IOYR 6/4); compact, massive, stony sandy silt. 

Stones angular to rounded, range from pebbles to 

boulders; a few soled, faceted, or striated; most of 

crystalline rock, in part fresh, in part stained brown· 

and decomposed. · Latter are rounded and appear to 

be derived from underlying conglomerate of Tertiary 

age. A few stqnes of hard or crumbly limestone and 

sandstone an? a very few of dark porphyritic volcanic 

rock. Thin layers of pinkish silt in lower part 

derived from Mesozoic redbeds __________________ _ 

Sand and gravel; beds of medium-grained gray, pepper 

and salt sand and clean fine sand, 2 to 3 feet thick, 

overlying angular pebble and cobble gravel of crystalTbickness 

(feet) 

3o-4o 

20 

line rock in an arkosic sandy matrix______________ 10 

Disconformity. 

Cedar Ridge Till: 

Stripped soil, B horizon, yellowish-brown (IOYR 5/4); 

compact, stony, sandy, clayey till; structureless, 

weakly calcareous; locally developed on lenses of 

sandy angular gravel at top of till ______________ o-1. 3 

Cca horizon, very-pale-brown (10YR 7/4); compact, 

stony, sandy silt; strongly impregnated with calcium 

carbonate, strong platy structure. Like B horizon, 

locally developed on lenses of sandy angular gravel at 

top of till______________________________________ o-3 

Till, light-brownish-gray (lOYR 6/2); massive, unsorted, 

compact, stony, silty sand; contains a few huge . 

boulder~; local lenses of angular gravel as thick as 

15 ft at top. Stones like those in overlying tills 

but most fresh crystalline rock__________________ 4o-50 

Disconformity. 

Soil, B horizon, light-brown (7.5 Y R 6/4); massive, 

clayey silt; partly leached; probably loess or colluvium (only locally preserved). Carbonate extends 

down fractures and around cobbles in underlying 

conglomerate to depth of 5-6 ft_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 0-2 

Angular unconformity. 

Conglomerate of Tertiary age: 

Cobbles and boulders of crystalline rock in a matrix of 

arkosic sand; compact, crudely bedded. Material 

stained brown and many stones decomposed ______ 15o-200 

Section in escarpment of Sacagawea Ridge on the north side of 

Upper Din woody Lake; center, sec. 31, T. 5 N., R. 5 W. 

[Locality 2, fig. 159.1] Thickness 

(feetr· 

Stripped surface soil, B horizon, brown (7.5YR 4/4); 

loose, silty fine sand, eolian ________________________ 1/2-1 

Bull Lake Till: 

Soil, Cca horizon, light-brown (7.5 YR 6/4); stony, 

silty sand. Calcareous coatings on cobbles and 

boulders---------------------------~----------- 1-2 

Till, yellowish-brown (10.5 YR 5/4); locally light olive 

brown (2.5YR 5/4) ;.compact, friable, silty sand and 

unsorted, unsized subangular to angular pebbles to 

boulders. Numerous large boulders. Most stones 

fresh crystalline rock, but some decomposed · and 

some sedimentary rock, mostly limestone. A few 

soled, faceted, or striated ___ - __ - _________________ 15-40 

Disconformity. 

Dinwoody Lake Till: 

Soil, B horizon, dark-brown (7.5YR 4/4); stony, clayey 

silt, structureless ___________ - _- _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ 2-3 

Till, light-brown (7.5 YR 6/4) to light-yellowish-brown 

(IOYR 6/4); compact, stony, silty sand. Has distinct pinkish cast owing to fine • silt derived from 

Mesozoic red beds. Fewer boulders than Bull Lake 

Till. Stones are angular tp subangular; a few . 

striated; most of fresh crystalline rock, but some of 

sedimentary rock, mostly limestone. A few rounded 

boulders of browri decomposed crystalline rock 

derived from nearby conglomerate of Tertiary age__ 30-40 

Silt and fine gravel, bedded, probably outwash _______ 15-20 

Disconformity. 

Sacagawea Ridge Till: 

Stripped soil, Cca horizon, yellowish-brown (10 Y~ 5/6) ; 

stony, sandy silt. Calcareous coatings along fractures and around stones. Rocks in till immediately 

beneath zone of fractures are crumbly ______ ·_______ 5-6 

Till, pale-brown to light-yellowish-brown (10 YR 6/3-

6/4); compact, .stony, silty sand. Stones mostly 

crystalline rock; high proportion rounded boulders of 

brown decomposed granitic rock derived from nearby 

conglomerate of Tertiary age. A few are sedimentary rock and a very few pebbles are dark dense 

porphyritic volcanic rock _____________________ - _- 5o-60 

Quartz sand and arkosic sand; clean, bedded, probably outwash _______________________________________ 1Q-15 

Angular unconformity. 

Conglomerate of Tertiary age: 

Cobbles and boulders rounded to subrounded, of crystalline rock in arkosic sandy matrix. Material 

stained brown and most cobbles and boulders deeply 

decomposed. Deposit crudely bedded __________ --- ± 200 

The ti1ls in the above sections vary somewhat in 

thickness along the escarpments. On .Cedar Ridge, 

the Dinwoody Lake Till is in places more than 100 

feet thick. The soils are not continuous horizons, but 

are preserved locally along intertill contacts and are 

so stripped by erosion that only their lower parts remain. Thus the colors are not as red nor is the material as clayey as that of the upper part of more fully 

preserved pre-Bull Lake soils in the area. 
ARTICLE 159 D135 

On the southeast .$ide of Bull Lake, the Dinwoody 

Lake Till forms a broad, smooth moraine which extends east\vard into outwash gravel on a terrace above 

and beyond the moraines of the Bull Lake Glaciation 

ttnd nbout 360 feet above the Wind River. In the 

same area, the Saqaga wea Ridge Till and the Cedar 

Ridge Till come to the surface and extend into outwash gravel on still higher terraces, 520 and 660 feet 

respectively, above the Wind River (fig. 159.2). 

A hypothesis for the erosional history in the Wind 

River ~fountains in pre-Bull Lake time is suggested 

by the distinctive lithologic differences of the three 

tills and their relation to terraces. Prior to glaciation, the conglomerate of Tertiary age completely 

covered the Mesozoic red beds and was itself cut by 

a pedimentlike erosion surface on which a soil had at 

least locally developed. 

The Cedar Ridge Till, consisting predominantly of 

fresh crystalline rocks, was obviously derived from 

the interior of the range rather than from the conglomerate on which it was deposited. The erosion 

surface on the conglomerate, over which the ice advanced, is about 1,000 'feet above the present canyon 

floor at the mountain front, and the associated outwnsh-gravel terrace lies about 660 feet above the 

Wind River. 

The composition of the Sacagawea Ridge Till, a 

mixture of fresh crystalline detritus, abundant rounded 

brownish-stained decomposed crystalline boulders from 

the conglomerate of Tertiary age, and small amounts 

of Paleozoic and Mesozoic sedimentary rock, suggests 

that the ice was advancing in a valley cut in the conglomerate of Tertiary age beneath which. Mesozoic 

sedimentary rocks were locally exposed. The top of 

the Mesozoic rocks is about 200 feet below the older 

pediment on ·the conglomerate and about 800 feet 

above the canyon floor ; the outwash terrace associated 

with the Sacagawea Ridge Till is about 150 feet below that associated with the Cedar Ridge Till and 

510 feet above the Wind River. 'The valley down 

which the ice advanced in Sacagawea Ridge time was 

therefore about 200 feet deep at the mountain front 

and 150 feet deep in the basin. 

The composition of the Dinwoody Lake Till, pre-· 

dominantly a pink silty sand containing abundant 

fresh crystalline and sedimentary rock, but little mater.ial from the conglomerate of Tertiary age, suggests 

that the ice advanced down a canyon cut well into the 

Mesozoic red beds from which its pinkish color is 

derived. At its maximum, the ice filled the canyon, 

overflowing the conglomerate of Tertiary age and 

· overlying tills to form a lateral moraine on the canyon rim. The fact that ·along the Wind River the 

outwash terrace associated with the Dinwoody Lake 

Till is 360 feet above the river, whereas that associated with the Bull Lake Till is only 150 to 200 feet 

above, suggests that the floor of the canyon down 

which the ice advanced in Dinwoody Lake time may 

have been about 500 feet below the pediment and 400 

to 500 feet above the present canyon floor at the 

mountain front. · 

The Cedar Ridge Till,· the Sacaga wea Ridge Till, 

and the Dinwoody Lake Till are believed to be 

equivalent to three pre-Bull Lake, "pre-Wisconsin" 

tills having similar topographic and stratigraphic settings in the La Sal Mountains, Utah, and in Glacier 

National Park, Mont. (Richmond, 1957). They may 

also be equivalent to the Rocky Flats Alluvium (oldest), Verdos Alluvium, and Slocum Alluvium of the 

Denver Basin, which in turn are correlated with the 

Nebraskan, Kansan, and Illinoian Glaciations of the 

midcontinent region (Scott, 1960). However, for purposes of correlation in the Rocky Mountain region, 

the terms Cedar Ridge Glaciation, Sacagawea Ridge 

Glaciation, and Dinwoody Lake Glaciation are proposed from the type localities of their respective tills. 

REFERENCES 

American Commission on Stratigraphic Nomenclature, 1961, Code 

of stratigraphic nomenclature: Am. Assoc. Petroleum Ge-

. ologists Bull., v. 45, p. 645-665. 

Blackwelder, Eliot, 1915, Post-Cretaceous history of the mountains of central western Wyoming: Jour. Geology, v. 23, 

p. 97-117, 193-217, 307-340. 

-- 1931, Pleistocene glaciation in the Sierra Nevada and 

Basin Range: Geol. Soc. America Bull., v. 42, p. 865-922. 

-- 1950, Pleistocene geology of the Green River Basin, 

Wyoming: Wyoming Geol. Assoc. 5th Ann. Field Conf., 

Southwestern Wyoming : Casper, Wyo., 196 p. 

Bradley, W. H., 1936, Geomorphology of the north flank of 

the Uinta Mountains: U.S. Geol. Survey Prof. Paper 

185-I, 204 p. 

Fryxell, F. M., 1930, Glacial features of Jackson Hole, Wyoming: Augustana Library Pub. 13, 128 p. 

Holmes, G. W., 1951, The regional significance of the Pleistocene deposits in the Eden Valley, Wyoming, p. 93-100, in 

Moss, J. H., Early man in the Eden Valley: Univ. Pennsylvania Mus. Mon., 124 p. 

Holmes, G. W., and Moss, J. H., 1955, Pleistocene geology of 

the southwestern Wind River Mountains, Wyoming: Geol. 

Soc. America Bull., v. 66, p. 629-654. 

Horberg, Leland, 1940, Geomorphic problems and glacial geology of the Yellowstone Valley, Park County, Montana: 

Jour. Geology, v. 48, p. 275-303. 

-- 1954, Rocky Mountain and continental Pleistocene deposits in the Waterton region, Alberta, Canada : Geol. 

Soc. America Bull., v. 65, p. 1093-1150. 
D136 GEOLOGICAL SURVEY RESEAR-CH 1962 

Morrison, R. B., 1961, New evidence on the history of Lake 

Bonneville from an area south of Salt Lake City, Utah: 

Art. 333 in U.S. Geol. Survey Prof. Paper 424-D, p. D125-

D127. 

Richmond, G. M., 1948, Modification of Blackwelder's sequence 

of Pleistocene glaciation in the Wind River Mountains, 

Wyoming [abs.]: Geol. Soc. America Bull., v. 59, p. 1400-

1401. 

--- 1954, Modification of the glacial chronology of the San 

Juan Mountains, Colorado: Science, v. 119, p. 614-615. 

--- 1957, Three pre~ \Visconsin glacial stages in the Rocky 

Mountain region: Geol. Soc. America Bull., v. 68, p~ 239-

262. 

--- 1960a, Glaciation of the east slope of Rocky Mountain 

National Park, Colorado: Geol. Soc. America Bull., v. 71, 

p. 1371-1382. 

--- 1960b, Correlation of Alpine and continental glacial 

deposits of Glacier National Park and adjacent High 

Plains, Montana: Art. 98 in U.S. Geol. Survey Prof. Paper 

400-B, p. B223-B224. 

--- 1961, New evidence of the age of Lake Bonneville from 

moraines in Little Cottonwood Canyon, Utah : Art. 334 in 

U.S. Geol. Survey Prof. Paper 424-D, p. D127-D128. 

Scott, G. R.; 1960, Subdivision of the Quaternary alluvium 

east of the Front Range near Denver, Colorado: Geol. 

Soc. America Bull., v, 71, p. 1541-1544. 

160. FAULTED PLEISTOCENE STRATA NEAR JACI{SON, NORTHWESTERN"WYOMING 

By J. D. LovE and D. W. TAYLOR, Laramie, Wyo., and 'Vashington, D.C. 

Unique and structurally complex unnamed Quaternary units, 8 igneous and 13 sedimentary, are present 

near the town of Jackson. Two of the sedimentary 

units-one lacustrine and the other eolian-that contain mollusks in some abundance are discussed in this 

article. Both units are significant because (a) they 

indicate widely divergent environments of deposition; 

(b) they are cut by normal fa~lts and, inasmuch as 

the younger unit contains shell material within the 

age range of carbon-14, they furnish data on timing, 

magnitude, and characteristics of localized Pleistocene 

and Recent faulting; (c) the mollusks provide correlation with similar assemblages elsewhere in the Western States; (d) the record of local .and regional 

crustal instability is pertinent to major construction 

projects in the Jackson area. 

LACUSTRINE SEQUENCE 

Excavations ·between 1958 and 1961 at 3 localities 

north of Jackson (fig. 160.1, locs. 1, 2, 3) exposed 

25-50 feet or more of olive-drab to gray claystone, 

siltstone, thin white concretionary marl beds, lightgray very soft fine- to coarse-grained sandstone, and 

brown andesitic grit and conglomerate. The andesitic 

debris consists of red and black deeply weathered 

angular fragments derived from directly adjacent 

flows of porphyritic andesite that comprise the youngest and locally the thickest (more than 1,100 feet) of 

the Quaternary igneous units in the area. Fossil mollusks characteristic of a lacustrine environment (Taylor, 1960) are found in all but the coarsest lithologies 

(see table) . 

·Occurrence, by locf!lities, of fossil shells in the lacustrine sequence 

and in loess 

[All localities (fig. 160.1) are In Teton County, Wyo. Geographic data are from U.S. 

Oeol. Survey Grand Teton National Park map (1951), 1:62, 500. Numbers in paren- theses are U.S. Oeol. Survey Cenozoic locality number, and collector's field number] 

Lacustrine Loess 

Species sequence 

------------------- 1 2 3 4 5 6 7 9 ----- - - - -

Fresh-water clams: A nodonta? __________________ X 

Pisidium compressum Prime __ ? X 

Fresh-water snails: 

Valvata humeralis Say ________ X 

V alvata utahensis CalL _______ X X 

Carinifex newberryi (Lea) _____ X X X 

Land snails: 

Pupilla muscorum (Linnaeus) _ X X X X 

Vallonia cyclophorella SterkL _ X X X 

cf. Succinea _____________ ---- X X X X X 

Discus shimeki cockerelli Pils- X X 

bry. Oreohelix _________________ - - X 

1. (22605; T61-38; L61-60A, unit 6}; 1,000 feet east of west lme and 1,400 feet south of 

north line of sec. 11, T. 41. N., R. 116 W.; road cut on west side of U.S. Highways 

26, 89, 187. 

2. (22606; T61-51; L61-61); 900 feet east of west line and 2,000 feet north of south line 

of sec. 11, T. 41 N., R. 116 W.; road cut on west side of U.S. Highways 26, 89, 187. 

3. (22607; T61-48); 1,100 feet south of north line and 1,250 feet west of east line of sec. 15, T: 41 N., R. 116 W.;'cut 100 feet west of the Old Wyoming Chuck Wagon 

Restaurant. 

4. (22608· T61-50; L61-63); 1,150 feet north of south line and 500 feet east of west line 

of se'c. 11, T. 41 N., R. 116 W.; road cut on west side of U.S. Highways 26, 89, 187 at first turnout on west side of highway, south of bend. . . 5. (22609; T61-49}; same as locality 3, but shells-are from loess overlymg lacustrme 

sequence. 6. (22610; L61-69); 800 feet north of south line and 2,650 feet west of east line of sec. 15, 

T. 41 N., R. 116 W.; road. cut on west side of U.S. Highways 26, 89, 187. 

7. (22611; L61-226); 1,200 feet south along section line from NW cor. sec. 27, T. 41 N., 

R. 116 W.; road cut on west side of U.S. Highways 26, 89, 187. 

9. (22642 and 2264.3; L61-95A and B); 1,700 feet south of north line !lnd 1,700 feet we~t 

of east line of sec. 32, T. 41 N., R. 116 W.; north wall of excavatiOn for cement-mIX 

plant. 
'\ 

8 

17 

20 

/ 

I 

I 

I 

1

29 

( 

I 

I 

ARTICLE 160 

I 

I 

I 

I 

I 

,/ , .; 

0 

R.116 W. 

I 

.I 

I / (/) ( 

9 I 10 l1 

I c5 I 

/ 

I 

I 

I 

I 

I 

116 i I 

\ 

I ~ I / 

21 ~ c3 

~ 

~28 

lJJ 

EXPLANATION 

--------- Contact 

Dashed where approximately located 

,---%-------····· 

High-angle fault 

14 

23 

26 

2 MILES 

Dashed where approximately located; dotted where concealed 

U, upthrown side; D, downthrown side 

X-4 

Fossiliferous loess locality 

16-2 

Outcrop of lacustrine sequence 

------ __ ... 

West margin of East Gros Ventre Butte 

T. 

41 

N. 

6750' 

6500' 

6250' 

A East Gros Ventre Butte 

0 

Area of ...... 

this report 

500 

WYOMING 

D137 

~--

Swamp 

deposits 

A' 

1000 FEET 

FIGURE 160.1.-Index map showing localities and features described in text, and geologic sketch map and section of Quaternary 

deposits and volcanic rocks at locality 1. Deposits of Recent age: slope wash and swamp deposits. Deposits of Pleistocene 

age: loess (stipple); outwash of Bull Lake Glaciation; lacustrine sequence (solid black); and porphyritic andesite. 
D138 GEOLOGICAL SURVEY RESEARCH 1 9 6 2 

In another excavation west of Jackson (fig. 160.1, 

loc. 8), the lacustrine sequence is composed of 17 feet 

of unfossiliferous dark-gray to brown soft plastic 

blocky claystone, light-tan soft fine-grained sandstone, 

and conglomerate. The conglomerate here contains 

fragments of gray basalt derived from an adjacent 

Quaternary igneous unit, 500 feet thick, and older than 

the andesite at localities 1, 2, and 3. 

. Regional relations indicate that the lacustrine sequence was deposited unconformably across the truncated edges of rocks ranging in age from Paleozoic to 

Quaternary. The sequence was faulted before the last 

pre.-Bull Lake glaciation (possibly the Buffalo Glaciation, which is generally considered to be of preWisconsin age) . 

The correlation of this lacustrine sequence with 

similar strata in other parts of Jackson Hole (Love, 

1960, p. 212-213) has not been established. Therefore, 

the size and duration of the lake in which the strata 

accumulated are not known. Two species found in 

the lacustrine sequence ( Oarinifew newberryi and Valvata. humeralis) live in Lake Tahoe, CaliforniaNevada, at depths between 120 and 300 feet (Hanna 

and Smith, 1938). Lake Tahoe has an area of about 

300 square miles, a maximum depth of 1,628 feet, and 

a mean depth of about 800 feet according to Hutchinson ( 1957). The former lake in Jackson Hole might 

have been of the same order of magnitude. 

INTERPRETATION OF MOLLUSKS OF LACUSTRINE 

SEQUENCE 

The lacustrine sequence is the only Pleistocene unit 

in .T ackson Hole known to contain locally extinct species. The occurrence of Valrvata utahensis, unknown 

elsewhere in Wyoming, is evidence of relative 

antiquity. 

Association of Oarinifew newberryi and Valrvata 

utahensis has been recorded in a number of localities 

in Idaho and Utah (Taylor, 1960). The oldest occurrence known is in the American Falls area, southeastern Idaho (Trimble and Carr, 1961). There, V. 

utahensis is, found in the fine-grained dominantly 

lacustrine Raft Formation. The overlying basal gravel 

of the American Falls Lake Beds containing V. utahensis and Oarinifew records an episode of greatly increased flow in the Snake River. At this time, pebbles were transported long distances down a broad, 

low-gradient valley. The simplest interpretation (but 

not the only possible one) is that the lacustrine sequence near Jackson is correlative with part of the 

Raft Formation, and the pre-Bull Lake glaciation 

with the basal gravel of the American Falls Lake 

Beds. If this correlation is correct an Illinoian, or 

Yarmouth and Illinoian, age for these events and 

deposits in Jackson Hole is most likely. 

Of the five species of mollusks found in the lacustrine sequence (see table) , V alrvata utahensis and 

Oarinifew r~Aewberryi live in either lakes or large slowmoving streams, whereas the other three may also live 

in small creeks only a few feet wide. Living and 

fossil occurrences of V. utahensis and Oarinifew are 

discontinuous (Taylor, 1960); their presence in Jackson Hole implies the persistence of a suitable lacustrine habitat, perhaps continuing from Pliocene time. 

The subsequent local extinction of V. utahensis suggests that the pre-Bull Lake (possibly Buffalo) glaciation was the first, and perhaps the only time thRt. 

Jackson Hole was largely filled with ice. 

POST-BULL LAKE LOESS 

Loess deposited during the interval between the 

Bull Lake and Pinedale Glaciations (medial and 

youngest of Pleistocene age in this region) covers 

large areas near Jackson (Fryxell, 1930). Average 

thickness is 10 to 20 feet, -yvith maximum of about 50 

feet. The loess consists of white to light-tan homogeneous massive soft porous silt, in places containing 

one or more secondary white calcareous layers. It 

overlies outwash of the Bull Lake Glaciation (figs. 

160.2 and 160.3) with angular unconformity in some 

places and with apparent conformity in others. Elsewhere, the loess was deposited on a surface of considerable relief cut in older rocks. Figures 160.2 and 

160.3 show the relations of the loess, outwash, and 

lacustrine sequences. One carbon -14 age determination 

FIGURE 160.2.- Quateruary sequences at locality 1; fault scarp 

of porphyritic andesite (Qa); post-Bull Lake loess (Ql); 

tilted outwash of Bull Lake Glaciation ( Qblo) ; lacustrine 

sequence (Qla), with dotted line marking main fossil zone. 
ARTICLE 160 Dl39 

FIGURE 160.3-Lacustrine sequence (Qla) at locality 1, folded 

into gentle anticline delineated by main fossil zone (dotted 

line) ; photograph overlaps left margin of figure 160.2 and 

shows same units marked by same symbols. 

suggests that the Bull Lake outwash may be about 

27,000 years old (Love, 1956, p. 149). The loess contains land snails in most outcrops. Carbon -14 ages 

of 13,980 -+-700 (W-1078; loc. 6) and 15,300 +500 

(W-1071; loc. 7) years have been determined from 

shell material (Meyer Rubin, written communication, 

1962; measurement done in laboratory of U.S. Geol. 

Survey). The maximum development of the Pinedale Glaciation in the central part of Jackson Hole 

may have been between 8,000 and 9,000 years ago 

(Love, 1956, p. 150). 

STRUCTURE INVOL VINO THE LACUSTRINE SEQUENCE 

AND LOESS 

The lacustrine sequence was downdropped 300 feet 

or more along a normal fault (fig. 160.1) at the base 

of the porphyritic andesite cliff shown in figures 160.2 

and 160.3. Most of this displacement was prior to 

Buffalo Glaciation. The downfaulted remnants of the 

lacustrine sequence were protected by the andesite and 

basalt cliffs at' the time the Buffalo ice overrode and 

scoured East Gros Ventre Butte. 

654685 0-62--10 

A second episode of normal faulting along a divergent and more extensive line of weakness occurred, 

in part at least, within the last 13,000-15,000 years, 

after the post-Bull Lake loess was deposited. During 

this episode, the valley of Flat Creek was downdropped 200 feet or more along a high-angle fault on 

the east side of East Gros Ventre Butte (fig. 160.1). 

The freshness of some parts of the scarp suggests 

that, at least locally, movement continued into Recent time. Renewed movement likewise occurred during this episode along the fault that had previously 

downdropped the lacustrine sequence at locality 1. 

Mild earthquakes are common in this area, but no 

severe ones have been recorded in the 75 years of continuous settlement. A comparison of similar Quaternary movements in the northern part of Jackson Hole 

with those associated with the Hebgen earthquake of 

1959, 90 miles north of Jackson, has been presented 

elsewhere (Love, 1961). The Quaternary geologic history of this region suggests that additional crustal 

movements can be expected, and this probability is, 

therefore, pertinent to the planning, design, and location of maJor construction projects in the Jackson 

area. 

REFERENCES 

Fryxell, F. M., 1930, Glacial features of Jackson Hole, Wyoming: Augustana Library Pubs. No. 13, 129 p. 

Hanna, G. D., and Smith, A. G., 1938, The mollusks of Lake 

Tahoe: Nautilus, v. 52, p. 34-36. 

Hutchinson, G. E., 1957, A treatise on limnology; v. 1, Geography, physics, and chemistry: New York, John Wiley 

and Sons, 1015 p. 

Love, J. D., 1956, Summary of geologic history of Teton 

County, Wyoming, during Late Cretaceous, Tertiary, and 

Quaternary times: Wyoming Geol. Assoc., Guidebook, 11th 

Ann. Field Conf., p. 140-150. 

-- 1960, Cenozoic sedimentation and crustal movement in 

Wyoming: Am. Jour. Science, v. 258-A, p. 204-214. 

-- 1961, Reconnaissance study of Quaternary faults in 

and south of Yellowstone National Park, Wyoming: Geol. 

Soc. America Bull., v. 72, p. 1749-1764. 

Taylor, D. W., 1960, Distribution of the freshwater clam Pisidium ·ultramontanum; a zoogeographic inquiry: Am. Jour. 

Science, v. 258-A, p. 325-334. 

Trimble, D. E., and Carr, W. J., 1961, Late Quaternary history of the Snake River in the American Falls region, 

Idaho: Geol. Soc. America Bull., v. 72, p. 1739-1748, 1 pl. 
D140 GEOLOGICAL SURVEY RESEARCH 1 9 6 2 

PALEONTOLOGY AND PALEOECOLOGY 

161. LATE CRETACEOUS DESMOSCAPHITES RANGE ZONE IN THE WESTERN INTERIOR REGION 

By W. A. CoBBAN, Denver, Colo. 

Ammonites belonging to the genus Desmoscaphites 

are widely distributed in the western interior of the 

conterminous United States. This widespread occurrence combined with its narrow stratigraphic range 

makes this genus an important and useful guide fossil. Reeside (1927a, distribution table) listed the 

known localities of the genus up through 1926. At 

that time only one species (D. bassleri Reeside) was 

known. Since then another species (D. erdmanrni Cobban) has been described and several new localities for 

both species have been discovered. The purpose of the 

present paper is to point out 'the characteristic features of the genus and its species, draw attention to 

the more important associated fossils; verify the age 

determination, and bring up to date all that is known 

of the distribution of Desmoscaphites. 

SCOPE OF THE GENUS 

Reeside (1927a, p. 16) established the genus Desmmwaphites to include moderate-sized scaphitoid ammonites that have stout well-rounded whorls, small 

umbilicus, constrictions on the early juvenile whorls, 

numerous primary and secondary ribs on the adult 

body chamber, and suture with trifid first lateral lobe. 

To this definition the present writer adds that the 

primary ribs on the adult body chamber terminate in 

small ventrolateral nodes, the nu~erous secondary ribs 

on the body chamber are evenly spaced or almost 

evenly spaced where they cross the venter, and all the 

lobes of the suture are trifid or tend to be trifid. 

Of the two described species of Desmoscaphites, the 

genotype, D. ba.ysleri Reeside (1927a, p. 16, pl. 21, 

figs. 17-21; pl. 22, figs. 8-12) is characterized by numerous secondary ribs on the adult body chamber and 

these tend to cross the venter with even spacing. 

There are 6 to 9 secondaries to each primary rib on 

the body chamber. The slightly older species, D. 

erdmutnni Cobban ( 1951a, p. 38, pl. 21, figs. 10-23), 

has 4 to 6 secondaries for each primary rib and, in 

addition, the secondary rib~ are a little more widely 

spaced along the venter in the middle part of the 

adult body chamber than near the aperture. 

IMPORTANT ASSOCIATED FOSSILS 

In the west~rn interior region the distinctive pelecypod Inoceramus patootensis de Loriol first appears 

in the Desmpscaphites erdmanni Range Zone and persists up through the D. bfMsleri Range Zone and into 

the middle part of the S caphites hippo ere pis Range 

Z'one. Likewise, Scaphites leei Reeside first appears 

with D. erdmanni, ranges up through the D. bassleri 

Range Zone, and persists into at least the lower part 

of the S. hippocrepis Range Zone. On the other hand 

Olioscaphites novimexicanus (Reeside) is a common 

associate of D. erdmanni' but is unknown with D. 

bassleri, and the ammonite described by Reeside 

(.1927a, p. 15, pl. 12, figs. 1-8) as Puzosia (Latidorsella) 1nancosen.si.'S is found with D. bassleri but not 

with the older D. erdmanni. Baculites th01ni Reeside 

is the most common baculite associated with both D. 

erdma;nni and D. bassleri .but ranges up into slightly 

younger rocks. In the western interior, all the known 

occurrences of the free-swimming crinoids Uintacrilnus 

and 11/ arsupites seem to lie in the Desmoscaphites 

Range Zone and most may be with D. bassleri. 

AGE 

In terms of the standard stages of the Upper Cretaceous, Reeside (1927b, p. 28) originally assigned 

Desmoscaphites bas$leri to the Santonian and later 

(1944) to the upper part of that zone. Desnwscaphittes 

erdmanni also has been placed high in the Santonian 

(Cobban, 1951b, p. 2197; Cobban and Reeside, 1952, 

correlation chart) . This late Santonian Age for both 

species of Desmoscaphites is suggested by the following factors : ( 1) Uintacrinus and 11/ arsupites, which 

seem to be confined to the DesntoscazJhites Range Zone, 

occur in Europe in the upper part of the Santonian 

(for example, Heinz, 1928, pl. 3), (2) Scaphites hippocrepis (DeKay), which occurs immediately above 

the Des1noscaphites Range Zone, is a well known guide 

fossil to the lower part of the Campanian Stage in 

Europe, and (3) InoCieramus cordiformis Sowerby, 

which is associated with Olioscaphites · ver1nijormis 

(Meek and Hayden) in rocks a little below those 

containing Des1noscaphites e~dmanni, is considered 

of middle Santonian Age (for example, Seitz, 1956, 

p. 4, 5). 

8oaphites hippocrepu was recorded with D. ba8sle1~i 

in the Telegraph Creek Member of the Cody Shale 

in south-central Montana (Reeside, 1927a, loc. 11208 

in distribution table; also see Thorn, and others, 1935, 

p. 56). The writer has not been able to locate the 

specimen or specimens on which this record was made. 
·f 

ARTICLE 161 D141 

113" 111. 109° 107° 1os• 

49° 

.. 35•Y-----------L---------~------~--~-L--------~ 

0 50 100 150 200 MILES 

FIOUJ~E 161.1.-Localities of Geological Survey collections of 

Desmoscaphites. Numbers refer to the description of localities in the table. Dotted line represents the approximate 

position of the shoreline during the age span of Desmosca,phites (the position of this line in Arizona and New MexIco is after Pike, 1947, fig. 7, line 7). 

Inasmuch as Scaphites leei, which closely resembles 

1 small forms of S. hippocrepi..ff, is the only scaphite 

associated with D. bassleri in the collections at hand, 

it probably is the scaphite from locality 11208. 

DISTRIBUTION 

Desmoscaphites is known from 36 Geological Survey Mesozoic' localities in the western interior region 

(fig. 161.1). In addition the genus has been recorded 

from a few localities in southwestern Colorado and 

northwestern New Mexico by Pike (1947, p. 23, 26, 

27, 43). Katich (1956, p. 118; 1959, p. 27) reports 

the genus in eastern Utah and western Colorado but 

does not give specific localities. 

The Geological Survey localities and species of Desmoscaphites are given in the following list. 

No. on figure 

161.1 

l__ --

2 ___ _ 

3 ___ _ 

4 ___ _ 

5 ___ _ 

Localities at which Desmoscaphites was collected 

Geological 

Survey 

Mesozoic 

locality Fossil 

7143 Desmoscaphites 

bassleri. 

21413 Desmoscaphites 

sp. 

24739 ____ do ______ ~_ 

D937 ____ do _______ ~ 

7138 Desmoscaphites 

bassleri. 

Description, collector, and date 

Top of ridge south of Lake 

Creek, about 2 miles east 

of Basin Mountain and 12 

miles west of Browning 

(approximately in SW}~ 

sec. 8, T. 32 N., R. 13 W.), 

Glacier County, Mont. 

Virgelle Sandstone. T. W. 

Stanton and M. R. Campbell, 1911. 

About 7 miles northwest of 

East Glacier, in NW%NE% 

sec. 15, T. 32 N., R. 13 E., 

Glacier County, Mont. 

Virgelle Sandstone. C. E. 

Erdmann, 1955. 

South Fork of Cut Bank 

Creek in NWXSEX sec. 4, 

T. 32 N., R. 12 W., Glacier 

County, Mont. Virgelle 

Sandstone. F. E. Turner, 

1953. 

Southeast side of U.S. Highway 2 about 7 miles 

northeast of East Glacier, 

in SE%SW}~NE}~ sec. 25, 

T. 32 N., R. 12 W., 

Glacier County, Mont. 

Virgelle· Sandstone. B. R. 

Alto, 1956. 

About 10 miles east of East 

Glacier, in NW% sec. 26, 

T. 31 N., R. 11 W., 

Glacier County, Mont. 

Virgelle Sandstone. T. W. 

Stanton and M. R. Campbell, 1911. 
D142 GEOLOGICAL SURVEY RESEARCH 19 6 2 

Localit'ies at which Desmoscaphites was collected-Continued 

No. on figure 

161.1 

6 ___ _ 

7 ___ _ 

8 ___ _ 

9 ___ _ 

10 __ _ 

11_ __ 

12 __ _ 

13 __ _ 

Geological 

Survey 

Mesozoic 

locality Fossil 

20299 Desmoscaphites 

erdmanni. 

216Q7 ____ do _______ _ 

21419 ____ do _______ _ 

21420 Desmoscaphites 

bassleri. 

D688 Desmoscap1J,ites 

erdmanni. 

D692 ____ do _______ _ 

D69~ ____ do _______ _ 

D666 Desmoscaphites 

sp. 

Description, collector, and date 

5 miles northwest of Kevin, 

in NE7~NW7~ sec. 24, T. 

35 N., R. 4 W., Toole 

County, Mont. Marias 

River Shale, 101 ft below 

top. C. E. Erdmann· and 

others, 1956. 

5 miles northwest of Kevin, 

in NE~ NE%NW?{ sec. 24, 

T. 35 N., R. 4 W., Toole 

County, Mont. Marias 

River Shale, 23 ft below 

top. C. E. Erdmann, R. 

W. Imlay, and J. B. Reeside, Jr., 1944. 

8 miles west of Shelby at 

head of ravine 3 miles 

north of Marias River, in 

NE~ sec. 31, T. 32 N., 

R. 3 W., Toole County, 

Mont. Marias River 

Shale, from limestone concretions 10 ft below top. 

W. A. Cobban, 1948. 

8 miles west of Shelby, in 

NE% sec. 31, T. 32 N., R. 

3 W., Toole County, 

Mont. Telegraph Creek 

Formation, from thinbedded sandstone 24-35 

ft above base. W. A. 

Cobban, 1948. 

9 miles west-southwest of 

Shelby, in E}'2NW~NEX 

sec. 31, T. 32 N., R. 3 W., 

Toole County, Mont. 

Marias River Shale, from 

5 ft below top. C. E. 

Erdmann, 1955. 

9 miles west-northwest of 

Shelby, in S%SW7~NW7~ 

sec. 31, T. 32 N., R. 3 W., 

Toole County, Mont. 

Marias River Shale, from 

29.5 ft below top. W. L. 

Rohrer, 1955. 

Same locality as D692. 

Marias River Shale, from 

9.5 ft below top. W. L. 

Rohrer, 1955. 

About 10 miles northwest of 

Conrad, in SE%NE% sec. 

28, T. 29 N., R. 4 W., 

Pondera County, Mont. 

Telegraph Creek Formation, from 105 ft above 

base. B. R. Alto, 1955. 

Localit·ies at which Desmoscaphites was collected-Continued 

No. on figure 

161.1 

14 __ _ 

15 __ _ 

16_--

17 __ _ 

18 __ _ 

19 __ _ 

20 __ _ 

21 __ _ 

Geological 

Survey 

Mesozoic 

locality 

D1128 

1404 

D3302 

11208 

1090.2 

10750 

10752 

21752 

Fossil 

Desmoscaphites 

bassleri?. 

Desmoscaphites 

erdmanni. 

____ do _______ _ 

Desmoscaph1'tes 

bassleri. 

_ ___ do _______ _ 

____ do _______ _ 

----do _______ _ 

_ ___ do _______ _ 

Description, collector, and date 

SE7~SW7~ sec. 28, T. 22 N., 

R. 8 W., Teton County, 

Mont. Telegraph Creek 

Formation. M. R. Mudge, 

J. J. Halbert, and M. B. 

Slaughter, 1956. 

Missouri River 4 or 5 miles 

below mouth of Marias 

River, Mont. Upper part 

of Marias River Shale. 

T. W. Stanton and W. H. 

Weed, 1894. 

About 2 miles south of Park 

City, in SW%NW~ sec.-6, 

T. 3 S., R. 23· E., Carbon 

County, Mont. Colorado 

Shale, 50 ft below top of 

Niobrara Member. J. R. 

Gill, 1961. 

SW% sec. 26, T. 1 S., R. 27 

E., Yellowstone County, 

Mont. Telegraph Creek 

Formation. W. T. Thorn, 

Jr., 1922. 

About 20 miles west of 

Hardin, in sec. 27, T. 1 S., 

R. 30 E., Big Horn 

County, Mont. Telegraph Creek Formation. 

W. T. Thorn, Jr., 1921. 

Between Shoulderblade 

Butte and St. Xavier 

Mesa, near south quartercorner sec. 27, T. 4 S., 

R. 33 E., Big Horn County, Mont. From soft 

sandstone below Virgelle 

Sandstone Member of 

Eagle Sandstone. T. W. 

Stanton and W. T. Thorn, 

Jr., 1921. 

Between Shoulderblade 

Butte and St. Xavier 

Mesa, near south quartercorner sec. 27, T. 4 S., 

R. 33 E., Big Horn County, Mont. Near base of 

Telegraph Creek Formation. T. W. Stanton and 

W. T. Thorn, Jr., 1921. 

South of Dry Muddy Creek, 

in SE%SW% sec. 22, T. 6 

N ., R. 1 W ., Fremont 

County, Wyo. Cody 

Shale, from 1,300 ft below 

top. J. B. Reeside, Jr., 

and others, 1949. 
J ( ~ 

I \f 

ARTICLE 161 D143 

-Loca.Uties at 1vldch Desmoscaphites was collected-Continued 

No. on figure 

161.1 

22 __ _ 

23 __ _ 

24 __ _ 

26---

26---

27 __ _ 

28 __ _ 

29 __ _ 

30 __ _ 

Geological 

Survey 

Mesozoic 

locality 

23110 

22102 

D3051 

11706 

D2509 

13247 

13248 

13249 

13250 

Fossil 

Desmoscaphites 

bassleri. 

____ ·do _______ _ 

____ do _______ _ 

_____ do ______ _ 

____ do _______ _ 

_ ___ do _______ _ 

_ ___ do _______ _ 

____ do _______ _ 

_ ___ do _______ _ 

Description, collt!Ctor, and date 

East Sheep Creek in NW% 

SEXNE~~ sec. 23, T. 6 

N., R. 2 E., Freemont 

County, Wyo. Cody 

Shale, from about 1,275 ft 

below top. .J. B. Reeside, 

Jr., and others, 1950. 

Six miles northeast of Rock 

Springs, in sec. 14, T. 19 

N., R. 104 W., Sweetwater 

County, Wyo. Baxter 

Shale, from 785 ft below 

top. L. A. Hale, 1950. 

About 12 miles south of 

Rawlins, in SE~~SW% 

sec. 23, T. 19 N., R. 

88 W., Carbon County, 

Wyo. Steele Shale, from 

a limestone concretion 180 

ft above base. J. H. 

Smith, 1961. 

Near Vermilion Creek, in 

SW~~NW~~ sec. 12, T. 

10 N., R. 101 W., Moffat 

County, Colo. Mancos 

Shale, from 2,275 ft above 

base. J. D. Sears, W. H. 

Bradley, and J. B. Ree- . 

side, Jr., 1923. 

5 miles north-northwest of 

Price, in SE}~NE~ sec. 

30, T. 13 S., R. 10 E., 

Carbon County, Utah. 

Mancos Shale, from lowest 

of 3 sandstone uriits making up Emery Sandstone 

Member. A. D. Zapp and 

W. A. Cobban, 1960. 

1 mile east of Desert, in 

SE}~ T. 20 S., R. 14 E., 

Emery County, Utah. 

Mancos Shale, from concretion 1, 710 ft above 

base. E. M. Spieker and 

J. B. Reeside, Jr., 1925. 

Same locality as 13247. 

Mancos Shale, from 1,750 

ft above base. E. M. 

Spieker and J. B. Reeside, 

Jr., 1925. 

Same locality ns 1324 7. 

Mancos Shale, from 1,900 

ft above base. E. M. 

Spieker and J. B. Reeside, 

Jr., 1925. 

Same locality as 13247. 

Mancos Shale, from 1,920 

ft above base. E. M. 

Spieker and J. B. Reeside, 

Jr., 1925. 

Local-ities at which Desmoscaphites was collected-Continued 

No. on figure 

161.1 

31 __ _ 

32 __ _ 

33 __ _ 

34 __ _ 

35 __ _ 

36_;.._ 

Geological 

Survey 

Mesozosc 

locality Fossil 

13280 Desmoscaphites 

bassleri. 

10434 ____ do _______ _ 

10484 ____ do _______ _ 

10141 ____ do _______ _ 

12005 ____ do _______ _ 

12013 ____ do------~-

Description, collector, and date 

4 miles east of old Box Bar 

ranch, in sec. 27, T. 31 S., 

R. 8 E., Garfield County, 

Utah. Mancos Shale, 545 

ft below Emery Sandstone· 

Member. James Gilluly 

and J. B. Reeside, Jr., 

1925. 

Just west of Durango, in 

center of sec. 13, T. 35 N., 

R. 10. W., La Plata 

County, Colo. Mancos 

Shale, 1,000 ft below top. 

T. C. Hopkins, 1920. 

Just west of Durango, in 

NW~SE}~ sec. 13, T. 35 

N., R. 10 W., La Plata 

County, Colo. Mancos 

Shale, 1,000 ft below top. 

J. B. Reeside, Jr., 1920. 

West foot of Hogback Mountain, in sec. 32, T. 30 N., 

R. 16 W., San Juan 

County, N. Mex. Mancos Shale, 280 ft below 

top. Harvey Bassler, 

1917. 

About 8 miles east of Shiprock, in SW}~NE}~ sec. 

20, T. 30 N., R. 16 W., 

San Juan County, N.Mex. 

M·ancos Shale, 190 ft below top. J. B. Reeside, 

Jr., 1923. 

East of Shiprock, in NEX 

NE}~ sec. 30, T. 30 N., 

R. 16 W., San Juan 

County, N.Mex. Mancos 

Shale, 435 ft below top. 

J. B. Reeside, Jr., 1923. 

REFERENCES 

Cobban, W. A., 1951a, Scaphitoid cephalopods of the Colorado Group: U.S. Geol. Survey Prof. Paper 239, 42 p. 

[1952]. 

--- 1951b, Colorado Shale of central and northwestern 

Montana and equivalent rocks of Black Hills : Am. Assoc. 

Petroleum Geologists Bull., v. 35, no. 10, p. 2170-2198. 

Cobban, W. A., and Reeside, J. B., Jr., 1952, Correlation of 

the Cretaceous formations of the western interior of "the 

United States: Geol. Soc. America Bull., v. 63, no. 10, 

p. 1011-1044. 

Heinz, Rudolf, 1928, Das Inoceramen-Profil der oberen Kreide 

Liineburgs: Niedersachsische geol. Ver. [Hannover] Jahrb., 

no. 21, p. 65-81. 

Katich, P. J., 1956, Some notes on the Cretaceous faunas of 

eastern Utah and western Colorado, in Intermountain 

Assoc. Petroleum Geologists, Guidebook 7th Ann. Field 

Conf., East~central Utah, 1956: p. 116-119. 
. D144 GEOLOGICAL SURVEY RESEARCH 19 6 2 

Katich, P. J., 1959, Late Cretaceous faunal zones, western Colorado, in Rocky Mtn. Assoc. Geologists, Guidebook 11th Ann. 

Field Conf., ·washakie, Sand Wash, and Piceance Basins, 

1959 : p. 26-29. -

Pike, W. S., Jr., 1947, Intertonguing marine and nonmarine 

Upper Cretaceous deposits of New Mexico, Arizona, and 

southwestern Colorado: Geol. Soc. America Mem. 24, p. 

1-103. 

Reeside, J. B., Jr., 1927a, The cephalopods of the Eagle Sandstone and related formations in the western interior of 

the United States: U.S. Geol. Survey Prof. Paper 151, 

87 p. 

-- 1927b, The scaphites, an Upper Cretaceous ammonite 

group: U.S. Geol. Suney Prof. Paper 15(}-B, p. 21-40. 

-- 1944, Maps showing thickness and general character of 

the Cretaceous deposits in the western interior of the 

' United States: U.S. Geol. · Survey Oil and Gas Prelim. 

Map 10. 

Seitz, 0., 1956, Uber Ontogenie, Variabilitiit und Biostratigraphie einiger Inoceramen: Palaeont. Zeitschr., v. 30, 

p. 3-6. 

Thoin, W. T., Jr., Hall, G. M., Wegemann, C. H., and Moulton, 

G. F., 1935, Geology of Big Horn County and the Crow 

Indian Reservation, Montana: U.S. Geol. Survey Bull. 

856, 200 p. 

162. THE OSTRACODE GENUS CYTHERELLOIDEA, A POSSIBLE INDICATOR OF PALEOTEMPERATURE 

By I. G. SonN, Washington, D.C. 

Invertebrate· fossils have been used as a means of 

interpreting paleotemperatures since N eumayr's work 

on climatic zones of the Jurassic and Lower Cretaceous. Neumayr (1883, p. 283), in turn, refers to earlier 

workers such as Romer (1852, p. 20-26) who mentioned the climatic influence on the distribution of 

rudistids. Accumulated paleoclimatological data recently have been summarized by Nairn (1961) and by 

Schwarz bach ( 1961). 

Data are here recorded for an ostracode genus 

known from the Jurassic to Recent. Because paleotemperature interpretations from other sources are 

available for the Upper Cretaceous, data for Upper 

Cretaceous and Recent species of this genus are presented. 

As with other organisms the distribution of marine 

ostracodes is controlled in part by temperature. Living representatives of this subclass are recorded from 

a minimum temperature of 0.0°C (32°F) at 1,900 

fathoms (Brady, 1880, p. 29) to 31 °C (87.8°F) 31t 

depths of less than a fathom (Kornicker, 1961, p. 59). 

Except for Elofson's ( 1941, p. 442-455) and Neale's 

( 1959, 1961) works on Pleistocene and Recent boreal 

forms, precise data on temperature ranges of individual taxa are not published; A statement by Kornicker 

( 1962), that representatives of the family Cytherellidae from the Bahama Banks would probably not survive at or below 13°C (55.4°F) for.extended periods, 

suggested the re.search upon which this preliminary 

report is based. 

I am grateful to Dr. L. S. Kornicker, Texas Agricultural and Mechanical College, for sending me a 

copy of the typescript of his forthcoming report; ~to 

Prof. Ed win C. Allison, San Diego State College, 

Calif., for unpublished information on ostracodes near 

Clipperton Island (fig. 162.1, loc. 39), and to one of 

his students, John C. Holden, for information on an 

Upper Cretaceous species of Oytherelloidea in California. 

The genus Oytherelloidea was erected by Alexander 

(1929, p. 55) to segregate species with ornamented 

shells from the marine benthonic species that were 

previously assigned to Oytherella Jones ( 1849, p. 28). 

Published descriptions and illustrations of all the living species of Oytherella were examined in order to 

determine which species actually belong to Oytherelloidea. The localities from which living species of 

Oytherelloidea have been recorded,· and a few unpublished occurrences, are shown on figure 162.1. 

Superposition of calendar-month isocrymes of surface-water temperature (Hutchins and Scharff, 1947, 

pl. 2) on this map limits the distribution of living 

species of Oytherelloidea to areas having a minimum 

temperature of approximately l0°C ( 50°F). Calendar-month isocrymes as defined by Hutchins and 

Scharff (1947, p. 266) are isotherms that connect 

points which cool down to the same extremes as measured in monthly mean temperatures. Although 

Oytherelloidea is a benthoni:c genus, a correction due 

to the decrease of temperature with depth is not made 

I'~ . 

'.• , 
140° 160° 180° 160° 140° 60° 40° 20° ·oo 20° 40° 60° 80° 

. 

60° 

40° 

~ 

1 i. ~ go •• 8~80 --~ ~ --~ 

>'I i 80 

j 

~~·t-·-

" 

60° +· +Recent Cytherelloidea . . 

1

.. ._ .. +----

! • Recent Cytherella 1 ' 

i .a. Upper Cretaceous Cyt~relloide~ I 

Base from US Navy Hydrographic Office chart 1262b, July 1941 

FIGURE 162.1.-Map showing the distribution of living species of Cytherelloidea and Cytherella and Upper Cretaceous species of Cytherelloidea, and calendar-month . 

isocrymes (degrees Fahrenheit) from Hutchins and Scharff (1947). 

> 

~ 

t-3 

~ 

0 

t"4 

~ 

..... 

0) 

~ 

d 

,_. 

~ 

C;l 
D146 GEOLOGICAL SURVEY RESEARCH 1 9 6 2 

b~ause precise data are not available. The error introduced by this fact is negligible, however, because 

most of the species are recorded from shallow depths. 

to 46 fathoms. 

Only two species of Oytherelloidea are known from 

depths lower than 46 fathoms. 0. irregularis (Brady, 

1880) and 0. a'l.tris Chapman, 1941, occur at 435 and 

470 fathoms respectively. 0. irregularis is known 

from "one or two detached valves" (Brady, 1880, p. 

178) from the vicinity of Bermuda (fig. 162.1, loc. 

59) where the isocryme is close to 21.1 °C (70°F), and 

any decrease of temperature due to depth will be well 

above the minimum determined for the genus. 0. 

auris is recorded from the southeast coast of Australia 

(loc. 25) at 33 miles east by south from Green Cape 

(lat 37°21'20" S., long 150°24'25" E.), at approximately the 12.8° C ( 55°F) isocryme. Both the depth 

and the location of this record are suspect (Chapman, 

1941, p. 152) because the location is in the area of a 

steep slope. A slight correction to the west would 

place this species in bottom tem·peratures above the 

minimum postulated for this genus. 

The distribution of living species o:f Oytherelloidea 

is bounded roughly by lat 40° S. and lat 37° N., and 

by the 10°C ( 50°F) isocryme, within the temperate 

and tropical biogenetic zones of Vaughan (Hedgepeth, 1957, p. 364). · 

The genus Oytherella appears to tolerate much 

wider tem-perature and depth ranges than Oytherelloidea. Oytherella lata Brady, 1880, is known from 

675 fathoms (Brady, 1880, p. 15) and :from a bottom 

temperature o:f 4.9°C ( 40.8°F) (idem., p. 23). The 

geographic range of this genus is from the equatorial 

region to the Arctic lat 73° N .. 

Localities :from which living species of Oytherella 

are r~orded are shown on figure 162.1. Species of 

Oytherella are associated with species of Oytherelloidea only within the temperature limits discussed, 

but Oytherella is :found consistently outside o:f the 

minimum temperature limits determined :for Oytherelloidea, suggesting that temperature is -probably the 

major factor that controls the distribution of Oytherelloidea. Additionally, this distribution supports 

Alexander's separation o:f Oytherelloidea as a genus 

distinct from Oytherella. · 

Douglass (1960, text fig. 1) shows the distribution 

of the foraminifer Orbitolina. This genus is inferred 

to have lived in tropical and subtropical waters having a temperature range of 15°C to 35°C ( 59°F to 

95°F). The northernmost record for Upper Cretaceous species o:f Orbitolina is :from southern England, 

about lat 51° N. or about 3lj2 ° of latitude farther 

south than species of Oytherelloidea o:f the same age. 

It therefore seems consistent that the probable minimum temperature during Late Cretaceous time at the 

northern limit :from which Oytherelloidea is recorded 

was not less ·than 10°C ( 50°F). 

A temperature range for Western Europe o:f about 

15°C to 21 °C ( 59'°F to 70°F) :for the Maestrichtian 

was inferred by oxygen isotope methods by Lowenstarn and Epstein ( 1954 p. 226, fig. 10), and by Bowen 

(1961). This range inferred by geochemical methods 

is compatible with the minimum temperatures inferred 

above by paleontologic methods. 

If the basic assumption is correct that the genus 

did not adapt with time to a different minimum temperature requirement, the distribution of fossil species 

of Oytherelloidea should give some clues as to paleotemperature. On figure 162.1 are shown the locations 

of Upper Cretaceous species of this genus from North 

America, Europe, and Africa. Each point represents 

from one to seven species, and from one to several 

samples. Oytherelloidea rwilliamsoniana (Jones) and 

0. chap1nani (Jones and Hinde), recorded by Chapman (1917~ p. 51, 52) from the Upper Cretaceous of 

southwestern Australia, are not used because they are 

probably from Lower Cretaceous sediments. The distribution of the genus during Late Cretaceous time 

ranged from Nigeria (fig. 162.1, loc. 85), about lat 

61j2 ° N., to North Germany (loc. 76), about lat 54° N., 

and from about long 55° E. in Russia (loc. 73) to 

about long 117° W. in the United States (loc. 35). 

REFERENCES 

Alexander, C. 1., 1929, Ostracoda of the Cretaceous of north 

Texas: Texas Univ. Bull. 2907, 134 p., 10 pis. 

Bowen, Robert, 1961, Oxygen isotope paleotemperature measurements on Cretaceous Belemnoidea from Europe, India 

and Japan: Jour. Paleontology, v. 35, p. 1077-1084, 3 figs. 

Brady, G. S., 1880, Report on the Ostracoda dredged by 

H. M. S. Challenger during the years 1873-1876: Report 

Sci. Results Voyage H. M. S. Challenger, Zoology, v. 1, 

pt. 3, 184 p., 44 pis. 

Chapman, Frederick, 1917, Monograph of the Foraminifera and 

Ostracoda of the Gingin Chalk : Australia Geol. Survey 

Bull. 72, 81 p., 14 pis. 

-- 1941, Report on foraminiferal soundings and dredgings 

of the F. I. S. "Endeavor" along the continental shelf 

of the south-east coast of Australia : Royal Soc. South 

Australia Trans., v. 65, no. 2, p. 145-211, pis. 7-9. 

Douglass, R. C., 1960, Revision of the ·family Orbitolinidae: 

Micropaleontology, v. 6, p. 249-270, 6 pis., 3 text figs. 

Elofson, Olof, 1941, Zur Kenntnis der marinen Ostracoden 

Schwedens mit besonder Berlicksichigung des Skageraks : 

Geologiska Bidrag fran Uppsala, v. 19, p. 215-534, 52 text 

figs. 

Hedgepeth, J. W., 1957, Marine biogeography, in Treatise on 

marine ecology and paleoecology, v. 1, Ecology: Geol. Soc. 

America Mem. 67, p. 359-382, 1 pl., 16 text figs. 

""' 

'1 

; 

-~ 
~· 

.. ! 

I 

~' 

ARTICLE 163 D147 

Hutchins, L. W., and Scharff, Margaret, 1947, Maximum and 

and minimum monthly mean sea surface temperature 

charted from the "World Atlas of sea surface temperatures": Jour. Marine Research, v. 6, p. 264-268, 2 pis., 

text fig. 69. 

Jones, T. R., 1849, A monograph of the Entomostraca of the 

Cretaceous of England: Palaeontographical Soc. London, 

40 p., 7 pis. 

Kornicker, L. S., 1961, Ecology and taxonomy of Recent Bairdiinae (Ostracoda) : Micropaleontology, v. 7, p. 55-70, 1 

pl. 

-- 1962, Ecology and description of Bahamian Cytherellidea (Ostracoda): Micropaleontology. (In press) 

I .. owenstnm, H. A., and Epstein, S., 1954, Paleotemperatures 

of the post-Aptian Cretaceous as determined by the oxygen 

isotope method: Jour. Geol., v. 62, p. 207-248, 22 text figs. 

Nairn, A. E. N., 1961, Descriptive paleoclimatology: New York, 

Interscience Publishers, 380 p., illus. 

Neale, J. W., 1959, Normanicythere gen. nov. (Pleistocene to 

Recent) and the division of the ostracod family Trachyleberididae: Paleontology, v. 2, p. 72-93, pis. 13, 14, text 

figs. 1-5. 

-- 1961, Normanicythere leioderma (Norman) in North 

America: Paleontology, v. 4, p. 424. 

Neumayr, M., 1883, Uber klimatische Zonen wtihrend der 

Jura-und Kreidezeit: Kais. Akad. Wissenschaften. Math.-

Naturwiss. Classe, Denkschr., v. 47, p. 277-310, 1 map. 

Romer, Ferdinand, 1852, Die Kreidebildungen von Texas und 

ihre organischen EinschHisse : Bonn, A. Marcus, 100 p., 

11 pis. 

Schwarzbach, Martin, 1961, Das Klima der Vorzeit: Stuttgart, 

Ferdinand Enke Verlag, 2d ed., 275 p., 134 text figs. 

SEDIMENTATION 

163. WIND DIRECTIONS IN LATE PALEOZOIC TO MIDDLE MESOZOIC TIME ON THE COLORADO PLATEAU 

By F. G. PooLE, Denver, Colo. 

Wcwk done in cooperation with the U.S. A.tomio Energy Commission 

The cross-stratified eolian sandstones of late Paleozoic 

to middle Mesozoic age on the Colorado Plateau are 

here divided into four major age groups: (a) the 

Weber Sandstone, of Pennsylvanian and Permian age, 

the vVhite Rim, Cedar Mesa, and De Chelly Sandstone l\1embers of the Cutler Formation, and the 

De Chelly and Coconino Sandstones, of Permian age; 

(b) the Wingate Sandstone and tongues of Wingate 

Sandstone in the upper part of the Chinle Formation, 

of Late Triassic age, and the Dinosaur Canyon Sandstone l\1ember of the Moenave Formation, of Late 

Triassic(?) age; (c) the Nugget Sandstone, of Early 

Jurassic age, Navajo Sandstone, of Jurassic and Triassic ( ~) age, and Aztec Sandstone, of Jurassic ( ? ) age, 

and tongues of Navajo Sandstone in the J(ayenta 

Formation, of Late Triassic ( ? ) age; and (d) the 

Carmel Formation, of l\1iddle and Late Jurassic age, 

and the Entrada, Bluff, Junction Creek, and Cow 

Springs Sandstones, of Late Jurassic age. No correlation or stratigraphic position of these subunits is implied within the four major groups. 

The portions of the sandstone units described in 

this paper are interpreted as dominantly eolian, although they contain some fluvial or marine strata, because their lithology and sedimentary structures are 

physically similar to modern dune deposits. Only a 

small proportion of the Weber, Dinosaur Canyon, and 

Carmel is considered eolian. The sandstones are, in 

general, light colored and are composed chiefly of 

quartz grains with subordinate amounts of feldspar, 

chert, and clay minerals. The bonding medium for 

the grains consists both of silica cement, in the form 

of quartz overgro·wths and microcrystalline quartz, 

and of carbonate cement. Grains range in size from 

very fine to coarse sand, with fine sand usually predominating. Most of the sandstones are moderately 

to well sorted. Sand grains range from subangular to 

well rounded; the larger grains are generally the better rounded. Pitting and frosting of the grains are 

common. 

Sedimentary structures consist of wedge-planar and 

subordinate tabular-planar, lenticular-trough, and lenticular-simple sets of cross strata. The lower boundary 

of a planar set is a plane surface of erosion; the lower 

boundary of a trough set is a curved surface of erosion; and the lower boundary of a simple set is a 

nonerosional surface (McKee and Weir, 1953). The 

deposits are composed almost exclusively of steeply 
D148 GEOLOGICAL SURVEY RESEARCH 19 6 2 

dipping cross strata, averaging between 20° and 30°, 

that formed on the lee sides of dunes. Sets of cross 

strata are separated by gently inclined erosional or 

depositional surfaces. The thickness of the sets ranges 

from about 2 feet to over 100 feet, and the length of 

the cross strata ranges from 5 feet to over 100 feet. 

Parallel asymmetrical ripple marks of long wavelength and low amplitude are numerous. The ripple 

index ranges from 20 to 50. 

Many features that are characteristic of modern 

dune deposits (Mcl{ee, 1957; Bagnold, 1954) are also 

characteristic of the sandstones studied. Both have 

(a) a high quartz content, indicative of a mature sediment, probably the result of several cycles of sedimentation; (b) a comparatively limited range of rock 

particle sizes (c) a high degree of rounding and sorting; and (d) pitting and frosting of the grains," probably resulting from abrasion by saltation. Modern 

dune deposits are composed almost exclusively of 

steeply dipping cross strata that form on the lee 

slopes; the gently dipping cross strata of windward 

sides, which slope in the opposite direction, rarely are 

preserved. Initial dips on the lee side of modern 

dunes usually range from 29° to 34°, which is the 

angle of repose for dry very fine. to medium-grained 

sand; measured lee-side dips of the ancient cross strata 

studied, however, average 5° to 10° less because the 

more steeply dipping cross strata at the top of each 

set were eroded prior to deposition of the overlying 

set. Dune deposits are made up of large- and mediumscale cross strata, and large-scale eolian cross-strata 

sets are dominantly wedge shaped. Eolian ripples are 

restricted to the parallel asymmetrical type with a 

high index, and they are subparallel to the dip direction of the cross strata on the lee slope and flanks of 

dunes. 

·The direction of transport of the sand is determined by measuring the direction of the steepest dips 

near the top of e~ch cross-strata set. At each locality, 

measurements were taken within a particular stratigraphic unit and were averaged to obtain a resultant 

wind direction. Due to the consistency in dip directions of the cross strata, 50 readings were usually s~fficient to obtain a significant trend. Each arrow shown 

in figure 163.1 represents the resultant dip direction of 

cross strata in a particular sandstone unit in the four 

major age groups at one or more localities. 

PENNSYLVANIAN AND PERMIAN TIME 

The orientation of cross strata indicates that prevailing winds during Pennsylvanian and Permian 

time were from the north and northeast during deposition of the upper part of the Weber Sandstone; from 

the northwest, north, and northeast for the White Rim 

and the Coconino Sandstone; from the northwest for 

the Cedar Mesa Sandstone Member; and from the 

north and northeast for the De Chelly (fig. 163.1A). · 

Regional stratigraphic relations of the Pennsylvanian and Permian units indicate that these sandstones tongue into marine strata westward and into 

continental strata eastward. These sandstone bodies 

are present along a north -south trending belt that is 

believed to represent a coastal-plain dune area in the 

western part and an inland-desert environment in the 

eastern part. This belt extends south-southwestward 

from southwestern Wyoming through eastern Utah 

into central Arizona. A southerly wind direction during deposition o:f these sandstones is shown in figure 

163.1A. 

TRIASSIC TIME 

The orientation of cross strata indicates prevailing 

winds from the nortlnvest, 'vith subordinate west 

winds, in Triassic time during deposition o:f the Wingate Sandstone; north west and northeast winds :for 

the tongues of Wingate Sandstone in the upper part o:f 

the Chinle Formation; and west winds for the Dinosaur Canyon Sandstone Member of the l\1oenave Formation (fig. 163 .. 1B). Cross-strata orientations in 

local eolian sandstone units in the "lower massive sandstone" o:f Mcl{ee ( 1954) in the Moenkopi Formation 

indicate winds from the northwest during Early and 

Middle ( ? ) Triassic time. The cross-strata measurements o:f the "lower massive sandstone" were made in 

two localities in northeastern Arizona. 

The local windblown sand bodies in the Moenkopi 

Formation of Early and Middle (?) Triassic age are 

believed to be dune accumulations marginal to a marine 

environment. The Wingate Sandstone and related 

sand bodies in the upper part of the Chinle Formation, all of Late Triassic age, are associated only with 

continental sediments and probably accumulated in an 

interior-desert environment. Prevailing winds blew 

toward the southeast during Triassic time (fig. 163.1B). 

LATE TRIASSIC ( ? ) AND EARLY JURASSIC TIME 

Cross-strata orientations indicate dominant north 

and northeast winds in Late Triassic ( ? ) and Early 

Jurassic time during deposition of the Nugget and 

Aztec Sandstones. Northwest winds prevailed during 

FOOTNOTES TO FIGURE 163.1 

1 Wilson, R. F., 1959, The stratigraphy and sedimentology of the 

Kayenta and Moenave formations, Vermilion Cliffs region, Utah and 

Arizona : Stanford Univ. Ph. D. thesis, 337 p. • 

2 Cadigan, R. A., 1952, The correlation of the Jurassic, Bluff, and 

Junction Creek Sandstones in southeastern Utah and southwestern 

Colorado: Pennsylvania State College Master!s thesis, 163 p. 

a Harshbarger, J. W., 1949, Petrology and stratigraphy of Upper 

Jurassic rocks of central Navajo Reservation, Arizona: Arizona Univ. 

Ph.D. thesis. 

( 

·~ 
}. 

•· 

\. 

., 

J, 

... 

~I 

ARTICLE 163 D149 

r-------~ I I 

I I 

i • L ___ /"A:QAj\w1ii[R"-----------~ 

i SALT LAKE CITY ~~At' SA:OSTONE \ 

: I I •DENVER \ 

I UTAH I 1 

1 0 •Grand COLORADO . •\ 

1 I Junction 1 

: a\a a; : CEDAR MESA \ 

I /ila I SANDSTONE 1 MEMBER I 

: • StGeorge ~ I • Durango ---- _ _j r.-"'------ -r ------------ T 

: /F' JF' ..-'f"• _!..DE CHEllY I 

-..J COCONINO E' I SANDSTONE I 

II 1F' JF' 1.e:.AE' II I 1 e SANTA FE 

'o lF' F1118!taff E'~ • Gallup \ 

~. lF' Fl {.:C..f.. \ 'I 

) F'\ p I NEW MEXICO I 

( SANDSTONE 

1

• 

' ARIZONA ~: ~~;ep;:;,:fs';;:!::~os!~~~ber of 

( • PHOENIX : Cutler Formation ' I C. g~~~:~ ::~~~a~!~dstone Member of 

(; : D. De Chelly Sandstone Member of ',......._ I Cutler Formation 

''-........,, : E. ~=i::e~~:~a~~ndstone (E' data from 

-........,, L F. Coconino Sandstone (F' data from 

'-------- Reiche, 1938) 

A. PENNSYLVANIAN AND PERMIAN 1 0:----------1 

i : 

1

: • L---A"-D'A-;:---N~~E-;;~~sTo~;-----~ I SALT LAKE CITY\A I ~I A I ~NO EQUIVALENT ROCKS \ 

I '·I A I I I I •DENVER I 

i UTAH~ i COLORADO \ I a a\aa 1 

' NAVAJo 8 , \ -......: I 

! B \a a~ : 

I

' \e\.1!. a, 1

1 I St ao, ' B a a I 

:~rael~a \ - \ : • Durango ------ __ _: 

~ZTEC ralot 0~~-lr.:--B""'S ----------- I c a· " a' -.t ~ c ,/ e.....,.' ' I r-' a, 8 I SANDSTONE SANDSTONE • SANTA FE 1 

\ ·~~ 'I I FJ~taff I 

\ NEW MEXICO \ 

I ARIZONA I 

{ A. Nugget Sandstone and equivalent • rocks 1 ... ' • PHOENIX B. Navajo Sandstone ( B' data from 

) Wilson') C. Aztec Sandstone (. D. Tongues of Navajo Sandstone in 

,,,,,'" ~:~::~ [ro~:~~j: ~~~ds~~eb; ~~~t -..... from Wilson!) ''-........,, __ · ____ _L __ j 0 100 

C. LATE TRIASSIC(?) AND EARLY JURASSIC 

,--------._, I : 

: I ----------, 

! SALT L:KE ::~--1----------- \ 

I I' : 

I •DENVER I I : 

I A"- lA "'Grand COLORADO : : UTAHA ~unction \ I A-......\ A......._ I I 

l A'\.A......._ A\~ WINGATE \ I "" A A' i SANDSTONE \ 

lst ~orge ~ 1 /'- : • Durango --------r--_j /oiN05AuR c=AA'\~s.t --------- ; ' CANYON A ~ I 

{

- j SANDSTONE c- A 1 ' MEMBER 3A B 1 

, /,~ eSANTA FE 1 I ·.~ •L 

~ • Gallup ~ A WINGATE : 

\ Flagstaff : SANDSTONE \ 

\, I, NEW MEXICO I 

ARIZONA 

J

' I A. Wingate Sandstone (called Lu- kachukai Member of Wingate Sand-

/ e PHOENIX ; stone in northeastern Arizona by 

\.... Harshbarger and others, 1957) ) I B. Tongues of Wingate Sandstone in ' , upper part of Chinle Formation (in- C.... 1 eluded in Rock Point Member of ,,,_ I Wingate Sandstone by Harshbarger 

'' , and others, 1957) ,,, j_' C. Dinosaur Canyon Sandstone Member 

''------- __ of Moenave Formation 

B. LATE TRIASSIC 

r-------~ 

j [_ ___ , ____________________ , 

I I I e I I SALT LAKE CITY : I I I I i : 'A eDENVER \ 

: 1 Grand 1 I UTAH _ E ~hunction COLORADO \ 

1 1

1 

lB 1 

i o, ::IB \ 

: o- IG/ : 

I o' F- oL G-4'Du J •St George A F- • G rango ----------.--- r-------y--H~A~-------- ; 

! H,- JH : /0 I rJ 1 : 

1 'Gallup e SANTA FE I 

) Fl~taff '1> NEW MEXICO : 

' A. Entrada Sandstone, undifferentiated \ B. Slick Rock Member of Entrada Sand- , ARIZONA stone 

II

, C. Moab Member of Entrada Sandstone D. Upper sandy member of Entrada 

1 e PHOENIX Sandstone 

\ E. !:~f~nsandstone bed of Carmel For-

(, F. Bluff Sandstone (data from Cadigan2) 

,, G. fr~r:;;~~~ig~~~}k Sandstone (data 

,,,_ H. Cow Springs Sandstone (H' data 

200 ,, from Harshbarger3) MILES ',........._ ______ L_ 

D. LATE JURASSIC 

EXPLANATION 

Approximate limit of deposition 

&rbs on side of nondepositW7! or erosion 

/ 

Generalized direction of wind 

FIGURE 163.1.-Wind directions during late Paleozoic to middle Mesozoic time, Colorado Plateau. 
D150 GEOLOGICAL SURVEY. RESEAR•CH 19 6 2 

deposition of the Navajo Sandstone except in southwest Utah and northwest Arizona, where north winds 

dominated. "\V"inds from the northwest were dominant 

during deposition of the tongues of Navajo Sandstone 

in the underlying Kayenta Formation (fig. 163.10). 

The writer believes that the Aztec Sandstone is 

equivalent to the Navajo Sandstone. Part of the Nug-· 

get Sandstone in northeast Utah and northwest Colorado is believed to be correlative with the Navajo of 

central Utah. 

The sandstones of Late Triassic ( n and Early Jurassic ag~ were deposited by prevailing winds blowing 

toward the south (fig. 163.10). These sand bodies, 

like the Wingate Sandstone, are associated only with 

continental deposits and probably accumulated in a 

vast interior-desert basin extending southwestward 

from central Wyoming through lJtah, northern Arizona, southeastern Nevada, and into southern California. 

LATE JURASSIC TIME 

Cross-strata orientations indicate dominant northeast and east winds during Late Jurassic time when 

the Entrada Sandstone was deposited, except during 

deposition of the upper sandy member in south-central Utah, when a north,vest and west wind prevaped 

(fig. 163.1D). Winds from the north and northeast 

prevailed during deposition of the Cow Springs Sandstone; from the west and southwest for the Bluff and 

Junction Creek Sandstones; and an east wind prevailed when the sandstone at the base of the Carmel 

Formation of Middle and Late Jurassic age was deposited (fig. 163.1D). The Bluff and Junction Creek 

are equivalent sandstone units. 

The sandstones of Late Jurassic age show a dominant southwest to west direction of transport of sand, 

except for the upper part of the Entrada Sandstone 

in south-central Utah and the Bluff-Junction Creek 

Sandstones, which show an east to northeast direction 

of transport (fig. 163.1D). Most of the eolian sandstones of Late Jurassic age are associated with marine 

strata in the western part of the study area, and they 

probably represent coastal-plain dune accumulations 

formed by reworking of beach deposits and regressive 

marine sands. Most of the Cow Springs Sandstone 

and the sandstones in the· eastern part of the area 

probably accumulated in an inland-desert environment. 

INTERPRETATIONS 

The sandstone units discussed in this paper are 

typical wind deposits comparable to modern dunes. 

The sandstones associated with marine strata are believed to be dominantly coastal-plain dune deposits 

derived from unconsolidated beach and regressive 

marine sands. Eolian sandstones associated with continental strata may have been derived from unconsolidated marine and marginal marine sands that were 

transported land ward, where they became associated 

with terrestrial sediments. On the other hand, these 

eolian sandstones may have been derived largely from 

older rocks exposed upwind. The sandstone bodies 

tend to thicken downwind, and many of them are 

thickest near their downwind limit. 

Dip directions of cross strata indicate that late 

Paleozoic and early Mesozoic winds on the Colorado 

Plateau and adjacent areas were relatively constant 

and blew in a southerly direction throughout much 

of that time (Poole, 1957). Local variations in wind 

direction were probably controlled by such factors as 

seasonal fluctuation in winds, relative position of land 

and sea, and the configuration and relief of landmasses. 

The consistency in dip directions of cross strata in 

these eolian deposits indicate northerly winds with 

great regularity and strength similar to our presentday northeast trade winds, which blow southwesterly 

(Poole, 1957). The consistency of cross-strata dip 

bearings in a southerly direction suggests that in late 

Paleozoic and early Mesoz.oic time a broad belt of 

strong and persistent northerly winds was present in 

the Colorado Plateau area between lat. 35° N. and 

43° N. This belt of "northerlies" may represent an 

ancient tradewind belt that extended from the equatorial zone to lat. 43° N. and beyond, or perhaps an 

expanded equatorial belt pushed the trade-wind belt 

northward. Persistent northerly winds in the Colorado 

Plateau area may have been due to a relatively stable 

high-pressure cell that was situtaed over the late 

Paleozoic-middle Mesozoic sea to the west. The clockwise movement of air around this high-pressure center 

would result in perennial "northerlies" in the eastern 

part of the high-pressure system. Another possible 

explanation is the hypothesis of polar wandering 

(Creer, Irving, and Runcorn, 1954). l\{easurements 

of remanent magnetism in rocks of the Colorado 

Plateau indicate that during late Paleozoic time the 

earth's magnetic pole in the northern hemisphere was 

in an area west of Japan and that during early 

Mesozoic time it was north of Mongolia, whereas during middle Mesozoic time it was near the present · 

geographic pole, as indicated by magnetism in Upper 

Jurassic rocks (Cox and Doell, 1960; Collinson and 

Runcorn; 1960) . If the earth's rotational axis were 

coincident with the axis of the mean geomagnetic 

dipole during the geologic past, the Colorado Plateau 

area would be within the northern hemisphere tradewind belt during late Paleozoic and early Mesozoic 

time, providing that the ancient planetary wind belts 

were similar to the present-day wind system. 

r 

·~ 

r 

.... 
~-

.... ' 

t' 

,., 

\, 

ARTICLE 164 Dl51 

. Divergent winds during deposition of some sandstones of Late Jurassic age, for example the upper 

part of the E'ntrada Sandstone (that is, upper sandy 

member and l\1:oab l\~ember) (fig. 163.1D), are believed to be the result of seasonal changes in wind 

direction due to. local .physiography as the shoreline 

fluctuated east-west. These divergent wind patterns 

may be due to monsoon winds or modified trade winds, 

or may represent the initial shift in the Colorado 

Plateau wind system from northerly to westerly 

winds. The easterly and northeasterly directions of 

transport indicated by the Bluff and tTunction Creek 

Sandstones suggest deposition by westerly winds. The 

eolian Chuska Sandstone, of Miocene ( ?) age, in northeastern Arizona and north western New Mexico was 

deposited by winds from the south-southwest (Wright, 

1956), indicating the existence of the westerly wind 

belt on the Colorado Plateau in Tertiary time. 

SELECTED BIBLIOGRAPHY 

Bagnold, R. A., 1954, The physics of blown sand and desert 

dunes: Reprint, London, Methuen and Co., Ltd., 265 p. 

Collinson, D. W., and Runcorn, S. K., 1960, Polar wandering 

and continental drift: evidence from paleomagnetic ob-, 

servations in the United States: Geol. Soc. America Bull., 

v. 71, no. 7, p. 915-958. 

Cox, A., and Doell, R. R., 1960, Review of paleomagnetism : 

Geol. Soc. America Bull., v. 71, no. 6, p. 645-768. 

Creer, K. M., Irving, E., and Runcorn, S. K., 1954, The direction of the geomagnetic field in remote epochs in Great 

Britain: Jour. Geomagnetism and Geoelectricity, v. 6, no. 

4, p. 163-168. 

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. 

McKee, E. D., 1954, Stratigraphy and history of the Moenkopi 

Formation of Tdassic age: Geol. Soc. America Mem. 61, 

133 p. 

-- 1957, Primary structures in some recent sediments: 

Am. Assoc. Petroleum Geologists Bull., v. 41, no. 8, p. 

1707-1747. . 

McKee, E. D., and Weir, G. W., 1953, Terminology for stratification and cross-stratification in sedimentary rocks: Geol. 

Soc. America Bull., v. 64, no. 4, p. 381-389. 

Poole, F. G., 1957, Paleowind directions in late Paleozoic aqd 

early Mesozoic time on the Colorado Plateau as determined by cross strata [abs.]: Geol. Soc. America Bull., 

v. 68, no. 12, p. 1870. 

Reiche, P., 1938, An analysis of cross laminations in the Coconino sandstone: Jour. Geology, v. 46, no. 7, p. 905-932. 

Wright, H. E., Jr., 1956, Origin of the Chuska sandstone, Arizona and New Mexico: A structural and petrographic 

study of a Tertiary eolian sediment: Geol. Soc. America 

Bull., v. 67, no. 4, p. 413-434. 

Wright, J. C., Shawe, D. R., and Lohman,· S. W., 1963, Definition of members of the Entrada Sandstone in eastcentral Utah and west-central Colorado : Am. Assoc. Petroleum Geologists Bull. (In press) 

164. LABORATORY STUDIES ON DEFORMATION IN UNCONSOLIDATED SEDIMENT 1 

By EDWIN D. 1\icl(EE, MAx A. REYNOLDS, 2 a.nd CLAUD H. BAKER, JR., Denver, Colo., Canberra, Australia, and 

Denver, Colo. 

Many structural forms produced through deformation of unconsolidated strata have been described and 

a voluminous literature has developed on this subject. 

Such structures occur in nearly all types of sedi1nentary rock and in all parts of the geologic column. 

They have been classified and interpreted in many 

different ways. · 

A series of .experiments on deformation in stratified 

and cross-stratified sediments is being conducted in 

the sedimentation laboratory of the U.S. Geologic~! 

1 The experimental work described in this article wus done by M. A. 

Reynolds und Clnud Bnkcr, Jr. under the direction of Edwin D. McKee. 

Mr. Y. Nlr of the Geological Survey of Isrnel assisted during the 

curly stages. 

2 Geologist, Australian Bureau of Mineral Resources. 

Survey in Denver, Colo. Each of the deformational 

processes described below has been applied to sand, 

clay, and alternations of each, and to saturated (that 

is, subaqueous), wet, and dry · (subaerial) sediments. 

Because many minor variables such as depth of water, 

degree of pressure, and others affect the final structure pattern, each experiment has been repeated many 

times in order to as~ertain the principal factors in-. 

volved. 

Definitions.-The purely descriptive term contorted 

stratification, recently defined (Dott and Howard, 

1962, p. 120) as "all disturbed stratification, regardless 

of inducing agent or agents * * *" is applied in this 

paper in the same sense. Probable synonyms are soft-
D152 GEOLOGICAL SURVEY RESEARCH 19 6 2 

rock deformation (Rettger, 1935, p. 272), gnarly bed-

. ding (McKee, 1938, p. 106), and disturbed structure 

as used by others. All of these terms imply deformation at any time after deposition, but before lithification, and by any process. l\1ostly the structures are 

restricted to single sets of strata or cross strata with 

rock units above and below entirely unaffected. They 

are intraformational features. 

Terms that have definite genetic implications, such 

as slump folds (Rigby, 1958, p. 310), flow structure. 

(Cooper, 1943, p. 190), and glacial contortion (Fairbridge, 1947, p. 105), are considered undesirable where 

interpretation is involved. Likewise those that have 

time connotations, as contemporaneous deformation 

(Lahee, 1914, p. 790) and penecontemporaneous deformation, are avoided in this investigation. 

Some terms applied to deformation of unconsolidated sediment are restricted to particular kinds of 

structures and may be considered subtypes of contorted stratification. They include convolute bedding, 

crenulated bedding, prolapsed bedding, overturned 

folds, and others. 

Basic types of deformed strata.-Contorted stratification, based on' physical form, may be grouped into 

four principal classes. These include among many 

others ( 1) highly irregular structures in which strata 

appear crumpled and twisted, rather than folded, 

(2) regularly folded· strata in which the axes are 

either horizontal or dip with low angle, ·(3) strata 

folded with axes essentially vertical, and ( 4) strata 

broken into a series of separate, nearly parallel, miniature thrusts or related tight folds. 

Terminology for basic types.-Terms applied to the 

principal types or classes of contorted stratification 

have been used differently by different authors and 

in a very loose sense by many. For this reason a 

descriptive, nongenetic terminology is applied in this 

investigation as indicated below. 

Highly irregular, crumpled and twisted strata are 

referred to as irregularly contorted beds. This usage 

is similar to that of Kuenen (1949, p. 368), who described Carboniferous rock of Pembrokeshire as 

"twisted, drawn out, or compressed in such a manner 

as to suggest kneading more than simple folding." 

Regularly folded strata with structures systematically bent to give the appearance Qf U's or V's on their 

sides are termed intraformational recumbent folds. 

"Overturned" as applied to cross strata by Potter and 

Glass (1958, p. 20) and by Stewart (1961, p. B129) 

is probably synonymous, but "recumbent" is preferred 

as it more precisely describes the normal attitude of 

the folds in terms of structural geology. The terms 

"prolapsed bedding" (Wood and Smith, 1957, p. 172) 

and "deformed ripple-drift bedding" (Prentice, 1960, 

p. 217) also seem to refer to this type of structure . 

Strata forming series of folds with nearly vertical 

axes ar~ termed convolute bedding. This term was 

proposed by J(uenen (1953b, · p. 1056) to describe 

laminae within a single set showing distortion that 

"gradually increases upward to intensive but rather 

regular folds and then dies out gradually." The term 

"crinkled bedding" used by l\1igliorini is a synonym 

according to Kuenen ( 1953a, p. 15), and various other 

terms such as "crenulated bedding," "curled bedding," 

and "corrugation" probably also refer to this structure. 

No genetic connotation is implied in the term as used 

here, although some geologists relate it to specific 

environments or processes. 

Repeated miniature thrust faults and related overturned fold structures within a stratification unit are 

designated as intraformational thrust structures. These 

commonly are distributed along a single stratification 

set with axes- tending to dip in one direction. They 

have been referred to as decollement structures (Hansen and others, 1961, p. 1415). 

Relation of type of sedirnent to deformation.-The 

type of structure developed in any particular situation 

depends, in part, on the kind of unconsolidated sediment that is subject.ed to deformation. Rigid discrete 

particles of sand react to forces of compression and 

tension very differently from clayey material, which 

tends to slide and slip und~r stress of lateral pressure. 

Thus, in experimental work typical intraformational 

recumbent folds of the type defined above have been 

developed only in sand, whereas intraformational 

thrust structures were formed best where clay layers 

occur between units of sand, as was convolute bedding 

under stress of vertical loading. 

Differences in structure also depend to ·some extent 

on whether the sediment involved is saturated; that 

is, under water, wet but with water drained off, or 

completely dry. The experiments of Rettger (1935, 

p. 286-288) have indicated the importance of this 

factor, and in the current investigations comparative 

tests have been made to ascertain its influence with 

respect to the forming of each structural type. 

Relation of physical process to deformation.-Four 

principal processes have been invoked by geologists to 

explain contorted stratification. These are ( 1) gravity 

slumping, (2) drag, as from an overriding force, 

( 3) overloading, from above or from one side, and 

( 4) modification by boring organisms, root growth, or 

gas bubbles. The first three of these have been tested 

in laboratory experiments involved in. the present 

study. 

I 

.

-~ 
0 1 2 3 

A B 

c 

0 1 2 3 I I I I 

E 

D 

FIGURE 164.1.-A, Convolute bedding developed in laminated mud layers between sand layers by vertical loading. Sandbag, responsible for contortions, partly visible 

in milky water above strata. B, C, Intraformational thrust structures in laminated mud .layers formed by progressive loading of sand from right to left. D, E, 

Intraformational recumbent folds developed in saturated sand by water currents forcing a mass of sand from right to left across top of foresets. Scale is in inches. 

> ;d 

8 

~ 

0 

t-t 

tr.l 

~ 

~ 

~ 

u 

1--" 

c.n 

C.IJ 
D154 GEOLOGICAL SURVEY RESEARCH 19 6 2 

Gravity slumping in unconsolidated sediments may 

result from weight increase at top of depositional 

slope, increase in water saturation, oversteepening, or 

undercutting of a depositional slope. It may be triggered by external impulses such as water movement 

or earthquakes (Rigby, 1958, p. 310; Hallam, 1960, 

p. 57). Regardless of cause, the results probably are 

similar. Slumping may occur on subaerial, as well 

as subaqueous slopes, but with somewhat different 

results. 

Surface. drag by an overriding force is commonly 

developed where masses of sediment are moved across 

a recently deposited surface by torrential or other 

strong currents. Similar forms result from glacial 

push (Fairbridge, 1947), and from subglacial drag, 

as suggested by numerous authors (Slater, 1927a, 

1927b; Jacobson and Scott, 1937; Opik, 1958, p. 58; 

Hansen and others, 1961, p. 1415). A distinction between gravity slumping and drag structures has been 

emphasized by Rettger (1935, p. 282), and he lists 

some criteria for distinguishing between the types of 

deformation. 

Deformation resulting from overloading is of two 

principal types (Prentice, 1960, p. 220). One type 

may be refer~ed to as vertical loading and is caused 

by local differences in a load settling· from above. 

Such local 1 settling has been attributed to turbidity 

currents (l(uenen and Menard, 1952, p. 90), but it 

may result from sediment raised by storm waves, 

from windblown sand or from volcanic pyroclastics 

dropping out of the atmosphere, and probably from 

other causes. The second type is horizonalload flowage which results from the weight of sediment accumulating on the margin of a current-fed deposit, 

as when a delta cone advances across a surface. 

Alteration of stratification and cross-stratification 

by the boring of animals, the growth of plants, or the 

migration of gas or liquid (Stewart, 1956) is not discussed here as it has not been included in the laboratory program .. The usual changes brought about by 

these processes, however, are of a highly irregular or 

nonsymmetrical type. 

Oonclusions.-Experiments to date have demonstrated that in saturated mud layers alternating with 

sand layers, convolute bedding can be formed by vertical loading (fig. 164.1A) ; intraformational thrust 

structures can be developed by horizontal flowage 

from progressive loading in a given direction (fig. 

164.1B and 0). Intraformational recumbent folds 

can be formed in saturated sand by the overriding 

force of a sand mass pushed forward by strong currents (fig. 164.1D and E). The experiments on recum bent folds are described in deta11 in Article 165; 

subsequent reports will discuss other types of contorted bedding as the work on each is completed. 

REFERENCES 

Cooper, J. R., 1943, Flow structures in the Berea Sandstone 

and Bedford Shale of central Ohio: Jour. Geology, v. 51, 

no. 3, p. 190-203. 

Dott, R. H., Jr., and Howard, J. K., 1962, Convolute laminations in non-graded sequences: Jour. Geology, v. 70, no. 1, 

p. 114-120. 

Fairbridge, R. W., 1947, Possible causes of intraformational 

distm;bances in the Carboniferous varve rocks of Australia: Royal Soc. New South Wales Jour. and Proc., v. 

81, pt. 2, p. 99-121. 

Hallam, A., 1960, The White Lias of the Devon coast: Geol. 

Assoc. Proc., v. 71, pt. 1, p. 47-60. 

Hansen, E., Porter, S.C., Hall, B. A., and Hills, A., 196i, Decollement structures in glacial-lake sediments : Geol. Soc. :America Bull., v. 72, p. 1415-1418. 

Jacobson, R., and Scott, T. R., 1937, The geology of the Korkuperril Creek area, Bacchus Marsh : Royal Soc. Victoria 

Proc., v. 50 (n.s.), p. 110-156. 

Kuenen, Ph. H., 1949, Slumping in the Carboniferous rocks of 

Pembrokshire: Geol. Soc. London Quart. Jour., v. 104, p. 

365-385. 

--· 1953a, Graded bedding, with observations on the Lower 

Paleozoic rocks of Britain: Verhandl. Kon. Ned. Akad. 

Wet., Eerste reeks, pt. 20, no. 3, 47 p. 

-- 1953b, Significant features of graded bedding: Am. 

Assoc. Petroleum Geologists Bull., v. 37, no. 5, p. 1044-

1066. 

Kuenen, Ph. H., and Menard, H. W., 1952, Turbidity currents, 

graded and non-graded deposits: Jour. Sed. Petrology, v. 

22, no. 2, p. 83-96. 

Lahee, F. H., 1914, Contemporaneous deformation: A criterion 

for aqueoglacial sedimentation: Jour. Geology, v. 22, no. 8, 

p. 786-790. 

McKee, E. D., 1938, Environment and history of the Toroweap 

and Kaibab Formations of northern Arizona and southern 

Utah: Washington, D.C., Carnegie Inst. Washington, pub. 

492, 268 p., 48 pl. 

Opik, A. A., 1958, The geology of the Canberra City District : 

Bur. Mineral Resources Australia Bull. 32. 

Potter, P. E. and Glass, H. D., 1958, Pennsylvanian petrology 

and sedimentation in southern Illinois: A vertical profile: 

Illinois Geol. Survey Rept. Inv. 204, 60 p. 

Prentice, J. E., 1960, Flow structures in sedimentary rocks: 

Jour. Geology, v. 68, no. 2, p. 217-224. 

Rettger, R. E., 1935, Experiments on soft-rock deformation : 

Am. Assoc. Petroleum Geologists, Bull., v. 19, no. 2, p. 

271-292. 

Rigby, J. K., 1958, Mass movements in Permian rocks of 

Trans-Pecos, Texas: Jour. Sed. Petrology, v. 28, no. 3, 

p. 298-315. 

Slater, G., 1927a, The 'st;ructure of the disturbed deposits of 

Mf:Sens Klint, Denmarl{). Royal Soc. Edinburgh Trans., v. 

55, pt. 2, no. 12, p. 289-302. 

-- 1927b, The disturbed gla('Jal deposits in the neighborhood of Lf:instrup near Hj~rring, North Denmark: Royal 

.Soc. Edinburgh Trans., v. 55, ph 2, no. 13, p. 303-315. 

... 
\ 

" 

ARTICLE 165 D155 

Stewart, H. B., 1956, Contorted sediments in modern coastal 

lagoon explained by laboratory experim~nts : Am. Assoc. 

Petroleum Geologists Bull., v. 40, no. 1, p. 153-179. 

Stewart, J. H., 1961, Origin of cross-strata in fluvial sandstone 

layers in the Chinle Formation (Upper Triassic) on the 

Colorado Plateau: Ai·t 54 in U.S. Geol. Survey Prof. 

Paper 424-B, p. B127-B129. 

Wood, Alan, and Smith, J. A., 1957, The sedimentation and 

sedimentary history of the Aberystwyth Grits (Upper 

Llandoverian) : Geol. Soc. London Quart. Jour., v. 114, 

pt. 2, p. 163-195, [1959]. 

165. EXPERIMENTS ON INTRAFORMATIONAL RECUMBENT FOLDS IN CROSSBEDDED SAND 1 

By EowiN D. Mcl(EE, MAx A. REYNOLos, 2 and CLAUD H. BAKER, JR., Denver, Colo., Canberra, Aus~ralia, and 

Denver, Colo. 

Equip1nent and m.aterials.-Experiments on the origin of intraformational recumbent folds were conducted in a steel delta tank, 15 feet long, 21j2 feet 

wide, and 2 feet deep, in the sedimentation laboratory 

of the U.S. Geological Survey, Denver, Colo. (Art. 

164). The tank at its inlet end contains a feeding 

platform with a front sloping at 30° to the floor. A 

stream, after flowing across this platform, built a 

delta into the standing body of water in front. Three 

valves at the outlet end controlled the level of the 

water. A cross section of the delta as it built forward could be observed through a clear plastic side 

of the tank. 

Relatively clean and well-sorted sand of two varieties was used for this set of experiments. One variety 

of sand, from dunes east of Denver, was brown, angular, low in sphericity, and showed the following 

size grades (~T entworth scale) on analysis: 

Coarse grains _______ _ 

Medium grains _____ _ Fine grains _________ _ 

Very fine grains ____ _ Silt _______________ _ 

Analysis 1 Analysis 2 

(percr.nt) (percent) 

11 

53 

31 

4 

1 

6 

56 

34 

3 

1 

The second variety was mechanically screened 

("flint shot," Ottawa Silica Co., Ottawa, Ill.) and 

averaged somewhat coarser than the dune sand: coarse 

grains 78 percent, medium grains 22 percent. It was 

white, welLrounded, and had fairly high sphericity. 

The two varieties gave similar results and, as the 

1 The experimental work described in this article was done by l\:1. A. 

Reynolds and Claud Baker, Jr. under the direction of Edwin D. 

McKee. 1\:lr. Y. Nlr of the Geological Survey of Israel assisted durIng the early stages. 

'2 Geologist, Australian Bureau of Mineral Resour<.-es. 

654685 o-62--11 

white was better for photographing, it was used in 

most final tests. 

Magnetite grains were used t<? mark stratification 

surfaces and were sprinkled periodically on planes of 

deposition. They made structure patterns conspicuous and were sufficiently heavy to be relatively stable 

once deposited. 

Preparation of sarnd deposits.-In ancient sandstones and in modern deposits of sand, intraformal 

tional recumbent folds commonly are formed within 

sets of cross strata, either tabular planar or trough 

(:M:~I(ee and Weir, 1953, p. 385). This is shown not 

only by association of the folded structures with cross 

strata of such types, but also by successions of recumbent folds that form lateral transitions into sets of 

normal foreset beds. In order to test fold development in this environment, each experiment was begun with a set of planar cross beds, having foresets 

dipping between 15° and 25° and surfaces 10 to 30 

inches long, formed in the delta tank. . The degree of 

dip was controlled by the rate of depositing current; 

the length of foreset by the depth of water. 

Emperi1nental procedure.-Pressure great enough to 

produce deformation was applied to sets of planar 

cross strata by each of several principal methods. 

These were: ( 1) loading from above with weights, 

(2) undercutting o foresets by ground-water seepage 

and by water currents near base, ( 3) oversteepening 

foreset tops to initiate gravity slumping, ( 4) pushing 

of near-surface part with a lateral force, and ( 5) 

dragging surface with an overriding force. Each of 

these processes was applied independently to saturated sand, wet sand with water withdrawn, and dry 

sand. 
D156 GEOLOGICAL SURVEY RESEAR!CH 19 6 2 

Theories of origin proposed by other researchers.-

The cause of intraformational recumbent folds in unconsolidated sand has been discussed by many geologists, and numerous theories, some very ingenious, have 

been suggested to explain them. Among these theories 

are (1) drag from the overriding force of sand-laden 

waters (Robson, 1956, p. 251), (2) the buildup of 

water pressure within a sanq. body covered by a mantle 

of silt, causing mass ·movement when a rapid lowering of water level outside took place (Harms, MacKenzie, and McCubbin, 1962), ( 3) the result of 

stresses set up between zones of freezing in waterimpregnated sand, thawed out during summer, and the 

permafrost below (Moskvitin, 1959, p. 727), ( 4) continued movement of loosely packed sand (quicksand) 

after the ·]ower part of a mass has settled (Stewart, 

1961), (5) slumping due to an oversteepening of the 

profile (Kiersch, 1950, p. 923). 

Slu.mping from. underoutting.-Gravity slump in 

pure sand caused by undercutting of foreset beds undoubtedly is responsible for some contorted stratification. The undercutting may result from internal 

weakening through ground-water seepage, from external attack through rising water level, or from erosion by currents. All of these methods were tried 

experimentally. 

With ground-water seepage through sets of cross 

strata, water followed a well-defined gently sloping 

plane and caused a zone of weakness where it emerged 

at the delta front. The resulting scarp retreated so 

gradually, however, that all trace of structure was 

destroyed as its front periodically collapsed. Similar 

results came from gradual undercutting by rising 

water level. 

· Other experiments in undercutting were done by 

suddenly removing a sizeable mass of sand a.t the 

base of a deposit, ·simulating .the effects of strong wave 

or current cutting. This was done by withdrawing a 

shingle from beneath the foreset front, causing collapse and drop of several inches. With both dry and 

saturated sand, planes of stratifi.cation were contorted 

but maintained definition (fig. 165.1A. and B). Strata. 

showed a marked tendency to curve forward and downward and to become wavy. Structures retained some 

degree of regularity but did not resemble recumbent 

f~d~ . 

Gravity slumping from oversteepening.-Gravity·· 

slumping structures were formed in two ways. In 

one a maximum angle of repose was developed by 

feeding sand very slowly with merely a trickle of 

water, after which the delicate .balance was disturbed 

by thumping the tank. A small avalanche of sand 

resulted and a more stable angle of repose was developed, but the slumping sand failed to preserve any 

clear-cut recumbent fold structures (fig. 165.10). The 

second experiment, involving a very rapid flow and 

a sudden cascading of sand masses down the delta 

front, likewise failed to bend over the laminae. In 

both experiments the slumping caused a flowing movem(mt of sand with a tendency to eliminate, "stretch," 

or weakly contort the strata. 

Vertical loading.-In experiments in which heavy 

weights were localized on the upper bounding surfaces of planar cross-strata sets, recumbent folds did 

not develop. Where the sand was below water level 

and saturated, a slight compaction resulted in warping (fig. 165.1 D and E). Where the sand was still 

wet, but water was drained off the mass, no effects 

could be detected. Where strata of dry sand close 

to the angle of repose were tested, a crinkling d~veloped in . the upper parts (fig. 165.1F). 

Pushing 1nith lateral jorce.-A laterally applied force 

similar to that of an advancing glacier has been suggested (Sussmilch and David, 1919; Slater, 1927 a, b; 

Hansen and others, 1961, p. 1415) as a possible cause 

of some contorted stratification. Such force was 

developed in laboratory experiments by pushing a 

board against the dissected end of a series of foreset beds 

(fig. 165.2 A, B, and 0). In this experiment, particles 

of sand were pushed forward along thrust planes parallel 

to the base of the board. The net result was a set of 

recumbent folds in which the upper limb was crinkled 

and particles within it displaced forward. 

The same experiment conducted with wet sand, 

stabilized and firm following withdrawal of water, 

produced no deformation under moderate pressure, but 

with greater pressure caused the strata to buckle, 

break, and move forward along what seemed to be 

.thrust planes. In dry sand a folded appearance was 

developed, but commonly the beds were not completely 

overturned as with a drag process. 

Drag from overriding force.-A sandbag was employed in order to simulate conditions oi an overriding force such as a mass of sediment or a body of 

ice moving across a set of planar cross strata. When 

testing wet sand with the water drained off, dragging 

the sandbag with a rope caused only a beveling of the 

surface. When saturated sand was used, either immediately after deposition or several hours later, the 

cross strata were strongly distorted with a dominant 

forward drag. Qn the other hand, when sand deposited under water had the water drained off and 

was then resaturated, the effect of dragging the sandbag over the surface was the same as for wet sand, 

and only beveling occurred. 
B 

A 

D 

c 

E F 

FIGURE 165.1.-Deformation of crossbedding in unconsolidated sand (scale in inches). A, Contorted bedding in dry sand caused by undercutting base of foresets. 

B, Contorted bedding in saturated sand caused by undercutting base of foresets. C, Contorted bedding in saturated sand caused by gravity slumping from oversteepening. D, Warping of beds in saturated sand resulting from vertical loading. E, Warping of beds in "quicksand" resulting from vertical loading. F, 

Crinkling of beds in dry sand resulting from vertical loading. 

> ;o 

8 

H 

0 

~ 

,_. 

0) 

01 

t1 

~ 

C)1 

-l 
A B 

c D 

E F 

FIGURE 165.2.-Deformation of crossbedding in unconsolidated sand (scale in inches). A and B, Crinkling in steeply dipping beds of dry sand caused by lateral push 

with board, from right to left as shown by the arrows. C, Crinkling in dipping beds of saturated sand caused by lateral push with board, from right to left as 

shown by the arrow. D, Recumbent folds in steeply dipping dry sand formed by dragging sandbag across upper surface. E and F, Recumbent folds in foresets 

of saturated sand caused by drag effect as mass of sand is moved acrt>ss surface by strong current. 

~ ~ y _). 

d 

...... 

C;l 

00 

0 

1?:1 

0 

t'i 

0 

0 

H 

('") 

> t'i 

UJ. 

c 

~ 

< 1?:1 

~ 

~ 

1?:1 

t/1 

1?:1 

> 

~ 

~ ,..... 

~ 

C) 

~ 
~1 

~ 

\~~' 

t<' 

1.., 

ARTICLE 165 D159 

In dry sand accumulated by avalanching, as on a 

dune-slip face, dragging a sandbag caused deformation resembling that formed in sa~urated sand (fig. 

165.2D). The beds were not completely "overturned," 

however~ and many minor crenulations developed. 

Recumbent folds similar to those formed by dragging a sandbag were. formed where a mass of loose 

but saturated sand moved as a body, pushed by the 

force of water behind, across the top of a set of foreset beds (fig. 165.2E and F). The moving mass of 

sand and ·water dragged the tops of the cross strata 

into recumbent folds, demonstrating that the mechanics of movement within the folded beds was the 

same as in beds dragged over with a sandbag, and 

that no gravity slumping is involved. It is concluded, 

therefore, that either a rigid mass like moving ice or 

the sudden movement of a body of sediment, as by 

flood waters, is capable of developing these structures 

in sediment that is saturated. 

Numerous variations in the form of intraformational folds produced in these experiments are readily 

explained by differences in several factors involved 

in the process as shown by repeated experi1nents : 

(1) 

(2) 

(3) 

The dip of the axial plane of the fold was directly related 

to the initial dip of the deformed beds; that is, the 

steeper the beds were initially, the greater the dip of the 

fold axis. . 

The point of folding seemed to be controlled by the water 

level in front of the delta; the folding occurred at or 

just below water level. 

The form of each fold varied according to the speed and 

duration of the overriding movement; other factors were 

constant. Where the drag was rapid and its distance 

of movement relatively large, the folds tended to be 

v-shaped ; with slower movements over a shorter distance, · more rounded folds were formed. 

In experimental work, S-shaped folds commonly developed with initial stress from drag. The upper 

lesser parts normally were soon removed by streamcurrent planation. This upper bounding surface, 

therefore, in folded as well as in undeformed sets of 

cross strata, commonly marks the surface above which 

a variable but unlmown amount of the original deposit was removed. In some cases the entire upper 

half of a fold was stripped away, leaving no record 

of deformation. 

Intraformational re(]Umbent folds in the geologic 

recorod.-Primary structures of this type are common 

in sandstones of various ages and in many parts of 

the world (see table). Most of these structures are in 

fluviatile deposits. Similar ones also have been recorded from modern strean1 deposits, including point 

bars of the Mississippi River (Frazier and Osanik, 

Records of typical intraformational recumbent folds in crossbedded 

sandstone 

Rock unit Age Locality Reference 

Nubian Sand- Cretaceous_ Libya, McKee (1962). 

stone. Egypt. 

Adigrat Sand- Jurassic(?) __ Ethiopia ___ Do. 

stone. 

Shinarump Triassic ____ Utah _______ McKee, Evenmember of sen, Grundy, 

Chinle For- 1953, p. 38. 

mation. 

Mossback ___ do _______ ___ do _______ Stewart, 1961. 

member of 

Chinle 

Formation. 

Caseyville Pennsyl- Illinois _____ Potter, 1957, 

Group. van ian. p. 2703, fig. 

7. 

"lower group" ___ Carbonif- SinaL ______ McKee (1962). erous. Fell Sandstone __ ___ do _______ England ____ Robson, 1956, 

p. 251. 

Old Red Sand- Devonian __ Scotland ___ Weston (in 

stone. Robson, 1956, 

p. 251). 

Aberystwyth Silurian ____ Great Wood and 

Grits. Britain. Smith, 1957, 

Canis ton Grits __ ___ do _______ ___ do _______ p. 171, fig. 5. 

Prentice, 1960, 

p. 217, fig. 1. 

Ram Sandstone_ Paleozoic ___ Jordan _____ McKee (1962). 

Torridan Sand- Precam- Scotland ___ Hemmingway 

stone. brian. (in Robson, 

1956, p. 251). 

1961, p. 135, fig. 10), the Red River, La. (Harms, 

MacKenzie, and McCubbin, 1962), and flood-plain deposits of the Colorado River, Ariz. (McKee, 1938, 

p. 81). 

REFERENCES 

Frazier, D. E. and Osanik, A., 1961, Point-bar deposits, Old 

River Locksite, Louisiana: Gulf Coast Assoc. Geol. Soc. 

Trans., v. 11, p. 121-137. 

Hansen, E., Porter, S. C., Hall, B. A. and Hills, A. 1961, Decollement structures in glacial-lake csediments: Geol. Soc. 

America Bull., v. 72, p. 1415-1418. 

Harms, J. C., MacKenzie, D. B., and McCubbin, D. G., 1962, 

Stratification in modern sands of the Red River, Louisiana: Jour. Geology. 

Kiersch, G. A., 1950, Small-scale structures and other features 

of Navajo Sandstone, northern part of San Rafael Swell, 

Utah: Am. Assoc. Petroleum Geologists Bull., v. 34, p. 

923-942. 

McKee, E. D., 1938, Original structures in Colorado River flood 

deposits of Grand Canyon: Jour. Sed. Petrology, v. 8, 

no. 3, p. 77-83. 

McKee, E. D., 1962, Origin of the Nubian and similar sandstones: Geologische Rundschau. (In press) 

McKee, E. D., Evensen, C. G., and Grundy, :w. D., 1953, Studies in sedimentology of the Shinarump Conglomerate of 

northeastern Arizona: U.S. Atomic Energy Comm., RME3089, 48 p. 

McKee, E. D., and Weir, G. W., 1953, Terminology· for stratification and cross stratification in sedimentary rocks: 

Geol. Soc. America Bull., v. 64, p. 381-390. 
D160 GEOLOGICAL SURVEY RESEARCH 1962 

Moskvitin, A. 1., 1959, New evidence of very early glaciation 

of the Russian Plain: Dok. Akad. Nauk SSSR, v. 127, 

no. 1-6, p. 852-856; English translation published by American Geol. Inst. in 1960 (p. 725-729). 

Potter, P. E., 1957, Breccia and small-scale Lower Pennsylvanian overthrusting in southern Illinois: Am. Assoc. 

Petroleum Geologists Bull., v. 41, no. 12, p. 2695-2709. 

Prentice, J. E., 1960, Flow structures in sedimentary rocks : 

Jour. Geology, v. 68, no. 2, p. 217-224. 

Robson, D. A., 1956, A sedimentary study of the Fell sandstones of the Coquet Valley, Northumberland: Geol. Soc. 

London Quart. Jour., v. 112, p. 241-262. 

Slater, G., 1927a, The structure of the disturbed deposits of 

M~ens Klint, Denmark: Royal Soc. Edinburgh Trans., v. 

55, pt. 2, no. 12, p. 289-302. 

-- 1927b, The disturbed glacial deposits in the neighborhood of L~nstrup, near Hj~rring, North Denmark: Royal 

Soc. Edinburgh Trans., v. 55, pt. 2, no. 13, p. 303-315. 

Stewart, J. H., 1961, Origin of cross-strata in fluvial sandstone layers in the Chinle Formation (Upper Triassic) 

on the Colorado Plateau: Art. 54 in U.S. Geol. Survey 

Prof. Paper 424-B, p. B127-B129. 

Sussmilch, C. A., and David T. W. E., 1919, Sequence, glaciation, and correlation of the Carboniferous rocks of the 

Hunter River District, New South Wales: Royal Soc. 

New South Wales Jour. and Proc., v. 53, p. 246-338. 

Wood, Alan, and Smith, J. A., 1957, The sedimentation and 

sedimentary history of the Aberystwyth Grits (Upper 

Llandoverian) : Geol. Soc. London Quart. Jour., v. 114, 

pt. 2, p. 163-195. [1959] 

ILLUSTRATIVE AND MAPPING TECHNIQUES 

166. EDGE ISOLATION IN PHOTOGRAMMETRY AND GEOLOGIC PHOTOGRAPHY 

By ALvA B. CLARKE, Washington, D.C. 

A process called edge isolation has been devised 

which transforms a normal continuously toned photograph into a photodiagrammatic representation. The 

areas of a photograph containing gradual tonal variations are subdued or eliminated while abrupt changes 

in density are rendered as gray or black lines. 

In order to produce edge-isolated photographs a 

special contact printer is needed, the essentials of 

which are a phosphor screen, a source of ultraviolet 

light, and a source of infrared light. Such a printer 

can be modified from one that is manufactured commercially for making aerial photographic prints. 

Basic to this photographic printing system is the phenomenon of photoluminescence, which is the property 

of certain substances (zinc sulfide, here) to absorb 

radiation o:f one wavelength and e·mit radiation of another wavelength. Absorption of ultraviolet radiation 

causes the phosphor to luminesce. The phosphor is 

inversely sensitive to infrared, however, so that exposure to this radiation causes a suppression of the 

I uminescence. 

Figure 166.1 is a schematic diagram of the printer 

components. The lamp ( UVL) radiates a range of 

ultra violet with a peak emission of 3,650 angstrom 

units, exciting the phosphor screen (P), which luminesces. The filter ( UVF) absorbs the ultraviolet 

shorter than 4,000 angstrom units and trans1nits vis0 0 0 0 0 0 0 0 0 0 IL 

----------------------------------IRF 

N 

--------------~~-----------------UVF 

p 

QuvL 

FIGURE 166.1.-Schematic diagram of the printer components. 

ible light. The filter (I RF) transmits infrared beyond the visible range emanating from the in candescent lamps (I L), quenching luminescence from 

the phosphor screen ( P) . Thus, the quenching action 

through a negative (N) converts the phosphor screen 

into a point-to-point image-modulated light source. 

A further aspect of the system, relative to the formation of outlines, is the manner in which abrupt 

changes in density are affected. Four factors determine when line formation will occur, and the ultimate 

~ 

}-
ARTICLE 166 D161 

A 

B 

FIGURE 166.2.-A, Normal contact print of aerial photograph; B, edge-isolated print. 
D162 GEOLOGICAL SURVEY RESEARCH 1962 

A B 

C D 

FIGURE 166.3.-.A, Normal contact print ·Of petrographic thin section; B, edge-isolated print. 0, Normal contact print of rock 

outcrop; D, edge-isolated print. 

_

I 
~· 

i. 

-,.1 

ARTICLE 166 Dl63 

width of the lines. They are ( 1) the distance over 

which the density change takes place (sharpness), (2) 

the amount of separation between the negative and 

the phosphor screen, · ( 3) the contrast characteristics 

of the negative, and ( 4) the degree of development 

(gamma) given the intermediate film positive and 

negative. When unexposed film is placed in contact 

with the negative and exposed simultaneously to the 

luminescence from the. phosphor screen and infrared 

from the quenching lamps, there occurs across the 

image edges, due to separation of the negative from 

the phosphor screen, an interaction of diffusion from 

each source of energy. After development, a line of 

increased density appears in juxtaposition to a line 

of decreased density, demarking the borders of the 

image. The effect produced is quite similar to the 

border effects of normal development, but greatly 

exaggerated. The effect persists over a wide range of 

density fluctuations on the original negative. By 

manipulation of the four factors outlined above it is 

possible to achieve any degree of edge enhancement, 

with or without an intermediate tone. 

The procedure followed for transforming a continuous-tone negative into an edge-represented copy is 

much the same as that for any negative duplication 

process. The negative is printed on a suitable stablebase negative film, the characteristics of which are 

dictated by the density and contrast of the original 

negative and the purpose for which the result is intended. The quenching action of the infrared modulates the emission of luminescence from the phosphor 

. screen, and upon development in a moderately contrasty 

developer the result is a film positive with two degrees of contrast. The continuous tone is now depicted as neutral gray bounded by narrow clear and 

dark lines. After processing and drying, the film 

positive is placed in the printer and a negative made 

from it. Higher or lower contrast is obtained by 

varying the developer for . this negative. Extremely 

high contrast for making pressplates or for use with 

other photomechanical processes is possible by developing the negative in a caustic developer, while maximum detail is retained by development in a mediumcontrast developer of the type used for ·commercial 

photography. 

Information in edge-isolated photographs is in a 

form that is in m·any ways more useful than in normal-perspective photogra.phs. The geometry of the 

photograph is not altered, as is seen in figure 166.2. 

The prints can be used for stereoscopic· analysis, rectification, and photomosaics, and they can be published as illustrations without using a halftone screen. 

Orthophotographs made with the edge-isolation technique show buildings, roads, woodlands, drainage, and 

other features by line images in true position. Research is being directed toward the use of this type 

of photoimagery in the production of standard planimetric-map substitutes. Patterns useful to geologists 

are often more easily identified in edge-isolated photographs than on continuous-tone photographs. .The 

technique promises to be useful not only as an analytical tool but also as a means of preparing scientific 

illustrations for which an accurate line image or 

sketch serves better than a photograph to illustrate 

features of interest. It is a quick and inexpensive 

means, for example, of preparing faithful camera-. 

lucida-like diagrams of petrographic thin sections 

(fig. 166.3A, B) or. drawings of fossils, sketches of 

rock outcrops (fig. 166.30, D), and perspective drawings illustrating geologic or physiographic relations 

from photographs or from oblique aerial photographs. 
D164 GEOLOGICAL SURVEY RESEARCH 1 9 6 2 

FIGURE 167.1.-A, View showing printed side of relief map. B, Identical area shown in A, but photographed from reverse 

side, with simplified overlay added. 
,... 

·-

.,.· 

ARTICLE 167 D165 

167. SHORTCUT METHOD FOR THE PREPARATION OF SHADED-RELIEF ILLUSTRATIONS 

By JOHN R. STACY, Denver, Colo. 

Shaded-relief diagrams :ne a valuable adjunct to 

technica( reports concerned with areal mapping or 

terrain interpretation. Such diagrams afford the 

reader a quick 3-dimensional impression of topographic details not otherwise readily obtained. 

In the past some authors have constructeq., then 

photographed, detailed terrain models. On occasion, 

the talented services of expert modelmakers have been 

employed. The relatively high cost for these services, 

however, has been a chief deterrent to their widespread use. More commonly, freehand pen and ink 

or airbrush drawings have been used. 

A new technique now being used by the Branch 

of Technical Illustrations, Denver, provides excellent 

and inexpensive 3-dimensional illustrations for publication, for any area covered by the plastic raisedrelief 1naps available from Army Map Service, Corps 

of Engineers. 

A photograph of a plastic relief map as usually 

viewed produces an undesirable array of illegible culture intermixed with lights, shadows, wooded areas, 

etc., as shown in figure 167.1.A. A shaded-relief 

base can be prepared from the same plastic model by 

photographing the reverse side of the model with the 

light source directed from the southeast rather than 

the usual north west, turning over the reverse-reading 

negative thus produced, and making a print. Figure 

167.1B is a base map of the same area as figure 167.1.A 

prepared by this procedure. When both sides of the 

model are photographed at the same scale, the photograph of the printed side (fig. 167.1A) can be used as 

base copy for compilation of a simplified overlay 

showing desired features such as coordinates, spot elevations, towns, and drainage (fig. 167.1B). Minor 

adjustments in drainage may be necessary to compensate for slight distortions caused by the molding process. 

AMS plastic-relief maps at a scale of 1:250,000 are 

now available for approximately 40 percent of the 

United States. The rna ps are particularly useful at 

this scale for the preparation of illustrations for regional physiographic studies, index maps, and so forth. 

Effective lantern slides and stereopairs are also quickly 

obtainable with .this method . 

HYDROLOGIC STUDIES 

GROUND WATER 

168. WINTER GROUND-WATER TEMPERATURES ALONG THE MULLICA RIVER, WHARTON TRACT, NEW JERSEY 

By E. C. RHODEHAl\IEL and S. M. LANG, Trenton, N.J. 

lV ork done in coopemtion with the New Jersey Division of lV ater Policy and Supply 

Winter ground-water temperatures were measured 

at a test site along the Mullica River as part of an 

investigation of ground-water movement in the Wharton Tract (fig. '168.1), a State-owned water reserye. 

The temperature data were used in an effort to improve the understanding of the mechanism by which 

water is added to the zone of saturation. 

Previous reports by the Geological Survey have described the well field and the geology and hydrology 

at the test site. Using tritium as a tracer, Carlston 

and others ( 1960) showed a distinct layering of 

ground water and that most of the discharge to the 

Mullic~ River was by lateral flow of ground water at 

the top of the zone of saturation. Lang ( 1961) and 
D166 GEOLOGICAL SURVEY RESEARCH 19 6 2 

N 

I 

0 

I 10 

I 20 

I 

30 MILES 

I 

FIGURE 168.1.-Map of southern New Jersey showing location 

of Wharton Tract (crosshatched). 

Lang and Rhodehamel ( 1962) confirmed this general 

pattern of ground-water movement by detailed studies 

of head distribution. The general movement is from 

· the upland areas on either side of the river to the 

stream; the major ground-water discharge area is in 

the northern part of the site near the confluence of 

the river and its tributary from the west. Groundwater head-measured on February 20, 1962, prior .to 

collection of temperature data-showed that the winter flow pattern (recharge period) was almost the 

same as that described by Lang (1961) for a summer flow pattern (nonrecharge period), except that 

the water levels were about 0.4 foot higher during 

the winter. 

Measurements o£ ground-water temperature and 

piezometric head were made in February 1962 in 11Jtinch-diameter wells installed in groups of 3 to depths 

of about 25, 50, and 100 feet. Observation-well sites 

were at intersections of a rectangular location grid 

numbered from 1 to 9 £rom west to east, and lettered 

from A to N from south to north. 

All the wells were pumped with a pitcher pump 

until the water temperature stabilized and temperatures were measured with a rapid-registering mercury 

thermometer calibrated to 0.1 °F. Lines of equal 

ground-water temperature were drawn at a 0.5°F interval for the shallow, medium, and deep zones and 

are shown in figures 168.2, 168.3, and 168.4, respectively. 

Figure 168.2 shows that the late-February pattern 

of temperature distribution in the shallow zone was 

highly complex. A U-shaped region of relatively cold 

water was found, the coldest water being in the vicinity of well 2E. The arms of the U extended eastward toward the Mullica River in the central and 

southwestern parts o£ the test site. East of the· river 

the temperature distribution was relatively uniform. 

Figure 168.3 indicates a less complicated pattern 

of temperature distribution in the medium-depth zone 

as compared to that in the shallow zone. The dominant temperature feature here was the irregularly 

circular pattern in the west-central part of the test 

site. The least complex pattern is shown in figure 

168.4 for the deep zone, where again the dominant 

feature is a circular area of lower temperatures in the 

western part of the test site. 

Cold surface water (34°F) in the swamp along the 

west border of the test site was observed to overflow, 

between wells· 2C and 2B (fig. 168.2), into the channel of an ephemeral stream from which water was 

observed to seep into the ground. Overflow from the 

N 

I ~ c 

EXPLANATION 

Swampy 

-

ground 

·3E 

Well mentioned 

in text 

0 100 FEET L.....L........ 

FIGURE 168.2.-Map of the Wharton Tract test site showing 

lines of equal ground-water temperature in the shallow 

water-bearing zone (25 feet) in late February 1962. Inter-

'Val 0;5°F. 

{ 

... 

.... 

'r-

-~ 

. ... 
.. 

·,_.. 

ARTICLE 168 D167 

N 

I 

EXPLANATION 

Swampy 

ground 

0 100 FEET l.__!_....j 

FIGURE 168.3.-Map of the Wharton Tract test site showing 

lines of equal ground-water temperature in the mediumdepth zone (50 feet) in late February 1962. Interval 0.5°F. 

swamp between wells lJ and lE drained into a small 

area about 25 feet southwest of 2E, where it sank into 

the ground. 

The temperature distribution in the shallow zone 

was affected directly by the concentrated recharge of 

cold water. However, vert~cal leakage between zones, 

which was demonstrated previously on the basis of 

head differentials (L~ng, 1961), also was indicated by 

the enclosed areas of lower temperatures in the 

medium-depth and deep zones. The enclosed area of 

lower temperature in the medium zone was displaced 

northeastward from the area of recharge near well 2E 

and also displaced northeastward from the center of 

cold water in the shallow zone. This displacement is 

due to the combined effect of greater horizontal than 

vertical permeability and the head distribution within 

the zone. The cold water beneath the ephemeral 

stream in the southwestern part of the test site did 

not affect the ground-water temperatures in the medium and deep zones, for the interzonal ground-water 

movement near the stream was vertically upward from 

the deep to the medium and to the shallow .zone, as 

indicated by the head measured in the wells prior to 

the temperature measurements. 

The high-temperature water in the shallow zone 

near well 3E probably represents a body of older 

water not influenced by the winter cold-water recharge. Because temperatures were lower in the medium and deep zones it is suggested that a shallow 

layer of clayey material prevents direct downward 

percolation of water from the 25-foot zone. 

During the period of temperature measurements 

there was no recharge to the aquifer east of the river. 

Water in the various zones in this part of the test 

site was of relatively uniform temperature, indicating 

adjustment to the geothermal gradient. 

The principal conclusions from the temperature 

measurements are that recharge to the zone of saturation can be detected by temperature measurements, 

but temperature data alone cannot be relied upon to 

trape the movement of ground water· within the test 

site; that details of the ground-water movement shown 

by the head distribution within the various depth 

zones, and details of leakage suggested by the differences in head between zones, are corroborated by 

temperature measurements in parts of the test site; 

a!ld that, because the horizontal permeability is greater 

EXPLANATION 

D 

Swampy 

ground 

0 100 FEET '---..J..-..1 

FIGURE 168.4.-Map of the Wharton Tract test site showing 

lines of equal ground-water temperature in the deep zone 

(100 feet) in late February 1962. Interval 0.5°F. 
D168 GEOLOGICAL SURVEY RESEAR'CH 19 6 2 

than the vertical permeability, the movement of 

·ground water is dominantly horizontal, which appears 

to be the factor responsible for the layering effect 

previously described by Carlston and others ( 1960). 

REFERENCES 

Carlston, C. W., Thatcher, L. L., and Rhodehamel, E. C., 1960, 

Tritium as a hydrologic tool-The Wharton Tract study: 

Internat. Assoc. Sci. Hydrologists Comm. Subterranean 

Waters Pub. 52, p. 503-512, 4 :figs. 

Lang, S. M., 1961, Natural movement of ground water at a 

site on the Mullica River in the Wharton Tract, southern New Jersey: Art. 313 in U.S. Geol. Survey Prof. Paper 424-D, p. D52-D54. 

Lang, S. M., and Rhodehamel, E. C., 1962, Movement of 

ground water beneath the bed of the Mullica River in 

the Wharton Tract, southern New Jersey: Art. 36 in U.S. 

Geol. Survey Prof. Paper 450-B, p. B90-B91. 

169. RELATION OF PERMEABILITY AND. JOINTING IN CRYSTALLINE METAMORPHIC ROCKS NEAR 

JONESBORO, GEORGIA 

By J. W. STEWART, Atlanta, Ga. 

Considerable information is available on the movement of ground water in the crystalline rocks of the 

Piedmont physiographic province in the Southeastern States in the zone tapped by water wells. It has 

generally been thought that the permeability of the 

crystalline rocks, d.ue mainly to jointing, decreases 

almost to zero within a few hundred feet of land 

surface. Ellis ( 1909, p. 68-69) stated that "* * * the 

greater the depth the greater must be the tendency of 

joints to close, owing to increased pressure * * *." 

The possibility of storage of gas underground in caverns excavated in the crystalline rocks led to exploration which shows that appreciable movement of water can take place in gneiss to depths as great as 500 

feet. 

The feasibility of underground storage of gas at a 

site near Jonesboro, Ga.; about 15 miles south of Atlanta, was investigated in 1961 by the Transcontinental Gas Pipe Line Corp., of Houston, Tex. Five core 

holes were drilled in a body of gneiss identified on 

the State geologic map of the Georgia Geological Sur-

. vey [1939] as biotite gneiss and schist of the Carolina 

Series of probable Precambrian age. 

The holes were spaced at distances of 0.2 to 0.4 mile 

and were cored to depths ranging from 490 to 509 

feet. Three of the cored holes were 1%6 inches in 

diameter and two were 2lj8 inches in diameter. The 

altitude of land surface at the test site ranged from 

about 840 to 940 feet above sea level. All the holes 

penetrated gneiss, ranging in composition from quartzfeldspar gneiss to hornblende-biotite gneiss (fig. 

169.1). Schistose-biotite gneiss was penetrated in two 

holes and jointed zones were noted at several depths 

in all five holes. The chief rock type was a quartzbiotite-feldspar gneiss. The crystalline rocks are overlain by a thick blanket of saprolite derived from their 

deep weathering. The dip of schistosity in the area 

is about 25 ° S. 30° E. 

Cores were taken at selected intervals, shown on 

figure 169.1, for permeability and porosity tests. Upon 

completion of coring, formation pressure tests were 

made by packing off 12-foot intervals in the holes and 

injecting water into the packed-off intervals for a 

period of 15 minutes under a pressure of 100 psi-

(pounds per square inch). 

The formation pressure tests were made with double pneumatic packers sealed with dry nitrogen at pressures ranging from 400 to 600 psi, although in 1 test 

hole the minimum packer pressure was 290 psi. Dry 

nitrogen was used to apply a constant pressure on 

each test section by means of a 3~ -inch connector pipe 

leading to the formation· interval being tested. The 

hydrostatic pressure maintained in each test interval 

was in addition to the static pressure in the hole. The 

bottom-hole pressure was maintained at 216 to 326 psi, 

or about a minimum of 1lj2 times the working pressure of the proposed cavern. The quantity of water 

injected into the formation for each section tested was 

determined by means of a. water-feed measuring device on the tank. Results in terms of water loss per 

minute during the tests are shown graphically on 

figure 169.1. The field and laboratory tests were 

made under the supervision of Fenix Scisson, Inc., 

Tulsa, Okla. 

4. 
ARTICLE 169 D169 

DATUM IS MEAN 

SEA LEVEL 

Core hole 1 

Water loss Lithology 

Core hole 2 

Water loss Lithology 

Core hole 3 

Water loss Lithology 

Core hole 4 Core hole 5 

Water loss Lithology Water loss Lithology 

H v H v H v H v H v 

.09 .07 

16 .12 

.30 0 

.30 0 

0 .08 

.06 .09 

0 .08 .21 .08 

.58 0 

Depth 490ft 

Depth 490ft 

Depth 509ft Depth 495ft 

Depth 500ft 

FORMATION PRESSURE 

TESTS EXPLANATION 

Water loss, in gallons 

per minute LITHOLOGY 

0.00-0.01 

~ ~ > 0.05 

[[[ill D 

0.01-0.03 Not tested 

0.03-0.05 • 

D 

Quartz-biotite-feldspar gneiss 

Quartz-biotite gneiss 

~ 

l~ Quartz-feldspar gneiss 

F-:~:01 

L;:;jd 

Schistose biotite gneiss 

liliili.ili] 

~ 

Hornblende-biotite gneiss 

EZ2J 

Joints 

Ticks on lithology columns 

show position of samples 

taken for permeabi_lity and 

porosity tests 

Numbers indicate permeability 

to air, in millidarcies; H, 

horizontal; V, vertic al. 

Absence of numbers indicates zero permeability 

FIGURE 169.1.-Lithologic logs and results of formation pressure tests, and laboratory tests of crystalline metamorphic rocks, Jonesboro, Ga. 

Permeability-to-air tests were made in the laboratory by placing core sections in rubber sleeves and 

maintaining a pressure differential of 50 psi for 1 

minute across the sample. Determinations were made 

of both horizontal and vertical permeability. A permeability of 0 was assigi).ed those cores through which 

no air flo~ed during the 1-minute period. The porosity was calculated by a comparison of the dry weight, 

saturated weight, and bulk volume of the samples. 

The laboratory tests indicated 0 permeability for 

most samples. All tests indicating greater than 0 

permeability are shown on figure 1. Porosity values 

for most samples (not shown in figure 169.1) were 

less than 1 percent; only 2 samples, from 458 'feet 

and 613 feet in core hole 1, were significantly higher, 

1.28 and 1.26 percent, respectively. 

The total footage tested in each core hole during 

the formation pressure tests ranged from 185 to 244 

feet. In 5 holes about 60 to 85 percent of the total 

sections tested showed water losses ranging from 0 to 

0.01 gpm (gallons per minute) ; in 3 holes 4 to 10 percent of the sections had water losses rang'ing from 
D170 GEOLOGICAL SURVEY RESEARCH 1962 

0.01 to 0.03 gpm; in 1 hole 4 percent of the section 

had a water loss of 0.03 to 0.05 gpm; and in 5 holes 

8 to 40 percent of the sections had water losses greater 

than 0.05 gpm. Although all core holes had a ppreciable water losses, the permeable zones in any one 

hole could not be correlated with those of any of the 

other holes. 

The formation pressure tests indicate that appreciable flows of water can occur in the dense crystalline rocks of the Piedmont even at depths as great as 

500 feet. Jointing noted in cores nearly always corresponded to zones of high water loss, but many zoneS 

of high water loss did not correspond to observable 

jointing. Laboratory tests of core permeability were 

not as definitive. Tests in intervals of high water 

loss commonly indicated negligible permeability in 

core samples, although most tests indicating measurable permeability corresponded to observable jointing 

or zones of high water loss. 

An approximation of the transmissibility of the 

gneiss at the site of the core holes was obtained by a 

method described by Theis ( 1954) of estimating transmissibility from specific capacity. By using a water 

loss of 0.05 gpm, a pressure head of 100 psi on the test 

sections, and a storag~ coefficient of 10· ~ the method 

gave results which plotted below the lower limits of 

the curves given by Theis, indicating rocks of relatively low permeability. However, the transmissibility 

was estimated to be less than 100 gpd (gallons per 

day) per foot, and is of the· same order of magnitude 

obtained for a 400-foot well drilled in similar rocks 

about 9V2 miles north of Jonesboro. The latter well 

was pumped at a rate of 25 gpm for 24 hours, and at 

the end of the test the total dra wdown in the well was 

295 feet. The transmissibility was computed to be 

45 gpd per foot. Several· other wells in the same area 

300 to 750 feet deep yielded 24 to 48 gpm during test 

pumping for 24 hours. In addition, 5 wells of the city 

of Jonesboro drilled in biotite gneiss, and ranging in 

depth from 200 to 370 feet, yield 7 to 18 gpm. It is 

expected, therefore, that wells drilled to depths of 

500 feet or more in the area of the core holes probably would yield 10 to 25 gpm. · i 

REFERENCES 

Ellis, E. E., 1909, A study of the occurrence of water in crystalline rocks: U.S. Geol. Survey Water-Supply Paper 232, 

p. 54-101. 

Theis, C. V. and others, 1954, Estimating transmissibility 

from specific capacity: U.S. Geol. Survey open-file rept., 

11 p. 

170. AQUIFERS IN BURIED SHORE AND GLACIOFLUVIAL DEPOSITS ALONG THE GLADSTONE BEACH OF 

GLACIAL LAKE AGASSIZ NEAR STEPHEN, MINNESOTA 

By R. W. MACLAY and G. R. ScHINER, St. P~ul, l\1:inn. 

Work done in cooperation with the Divi8ion of Water8, :Minne8ota Department of Con8ervation and the Yillage of 

Stephen, MinneBota 

Beach and glaciofluvial deposits are the principal 

sources oi ground water in the basin of glacial Lake 

Agassiz; the clayey lacustrine deposits yield ·little 

water, and the underlying bedrock. aquifers generally 

yield highly mineralized water. In the Halma-~ake 

Bronson area, beach and lake sand mantle productive 

aquifers in the underlying outwash deposits. Similar 

shore deposits in the Stephen area are covered by silty 

lacustrine clay, but will yield moderate quantities of 

water. The trend of these buried deposits is reflected 

locally by low linear mounds that parallel the Gladstone beach line of Upham ( 1896, p. 463) . Recognition of these subdued topographic expressions of 

buried beach deposits was of great assistance in locating test holes, in which substantial supplies of ground 

water for municipal use in the Stephen area were discovered. 

The floor of glacial Lake Agassiz may be divided 

on the basis of physiography and geology into two subareas along a line extending through Argyle and 

Stephen (fig. 170.1).. In the western subarea the surface slopes westward about 5 feet per mile and is 

underlain by lacustrine silty clay and dense clay. In 

the eastern subarea the surface slopes about 20 feet per 

..... 
)· 

:i.. 

.._J 

ARTICLE 170 D171 

CANADA 

R. 49 W. R. 48 W. R. 47 W. R. 46 W. R. 45 W. R. 44 W. Area.of this ---r-- report 

N. 

T. 

160 

N. 

T. 

156 

N. 

T. 

N . 

N 

1 

EXPLANATION 

Area of detailed investigation 

for ground water 

Beach ridge or mound 

--~· --....... ...__ 

Approximate boundary between 

area underlain by clay and 

silty clay (to the west) and 

area underlain by sand and 

till (to the east) 

• Test well 

5 0 5 10 MILES· 

FrauRE 170.1.-Map of northwestern Minnesota showing areas of ground-water investigations and trends of several beaches of 

glacial Lake Agassiz. 

mile westward and is underlain by lacustrine silty 

clay, lake-washed till, and shore and glaciofluvial deposits. The surface of the eastern s~barea is characterized by a series of gentle north-trending beach 

ridges. The boundary between the eastern and ~estern 

subareas is transitional, but in most places it is marked 

by a belt of dis~ontinuous mounds or by a slight steepening toward the east. 

Most of the Stephen area is mantled by clayey 

lacustrine deposits. Several test holes were drilled 

in search of beach and glaciofluvial deposits, and sandy 

glaciofluvial deposits about 20 feet thick were penetrated below 5 to 10 feet of lake clay near Argyle. 

These deposits had no topographic expression; however, they lie approximately in line with the trend of 

the Gladstone beach and could be traced northward 

654685 0-62--12 

along the trend of the Gladstone beach between Argyle 

and Stephen. Samples from some auger holes indicate 

an. upper sand unit of well-sorted fine- to coarsegrained quartzose sand over less well sorted glaciofluvial deposits, which consist largely of sand but also 

contain silt, gravel, and· clay lenses (fig. 170.2). In 

some places the glaciofluvial deposits are missing and 

the upper sand unit rests on sandy clay till. 

The upper sand unit presumably is a beach deposit 

that was reworked from the glaciofluvial deposits. 

Auger logs indicate that in the Stephen area as mnch 

as 70 feet of permeable glaciofluvial deposits underlie 

the beach deposits. All these beach and glaciofluvial 

deposits are covered by lacustrine clay, which probably was deposited during a lake transgression after 

the Gladstone beach was formed. 
D172 GEOLOGICAL SURVEY RESEARCH 19 6 2 

840' 

820' 

800' 

Clay 

0 

EXPLANATION 0--····-·· 

:.:.:... .... :.:.:._ ···-···· ·-···-· 

··-··· Sand Silt 

300 FEET 

Gravel Till 

FIGURE 170.2.-Generalized section across buried beach ridge 

near Stephen, Minn. 

Ground water in the buried beach and glaciofluvial 

deposits in the Stephen area is confined by the lacustrine clay. Water l.evels in most auger holes rose 

quickly in the overlying clay to within 5 to 15 feet of 

the land surface. Most of the recharge to the confined 

deposits probably occurs on the mounds where the 

overlying clay is silty. 

Two auger holes were cased with 2-inch pipe and 

pumped with a centrifugal pump to test the waterbearing capacity of the beach and glaciofluvial deposits. One well, equipped with a 2-foot screen extending to 27 feet, yielded 25 gpm (gallons per minute) 

for 2 hours from a clean fine- to coarse-grained sand. 

The second well tapped a similar sand but was not 

equipped with a screen. Th~ pipe was suspended from 

the ground surface and hung free in an open hole; 

the well was pumped at 80 gpm for 4 hours with no 

noticeable decline in production. 

Most of the deeper aquifers in the Stephen area 

contain highly mineralized chloride water. In general, water from the shallow outwash and beach deposits is less mineralized and has a lower chloride 

content than water from deeper aquifers, altb'ough 

there is much variation in the quality of water. Field 

analyses suggest that the chloride content of water from 

the glaciofluvial deposits is lowest in areas where the 

clay cover is . thin and recharge occurs by infiltration 

through the clay. Water from the well where the 

clay cover was only about 10 feet thick contained about 

30 ppm (parts per million) of chloride, and water 

from the other well, where the clay cover was about 

16 feet thick, contained about 280 ppm of chloride. 

SELECTED BIBLIOGRAPHY 

Schiner, G. R., 1962, Ground-water exploration and test pumping in the Halma-Lake Bronson area, Kittson County, 

Minnesota: U.S. Geol. Survey open-file rept. 

Upham, Warren, 1896, The glacial Lake Agassiz: U.S. Geol. 

Survey Mon. 25. 

'-1 
~·· 

~· 

-( 

~ 

ARTICLE 171 D173 

171. POTENTIAL YIELD OF DEEP WATER WELLS IN THE SOUTHERN PART OF THE JICARILLA APACHE 

INDIAN RESERVATION AND VICINITY, SAN JUAN BASIN, NEW MEXICO 

By ELl\fE:R H. BALTZ, S. ,V. vVEsT, and S. R. Asn, Albuquerque, N.Mex. 

W m·lc done in coopemUon with the J'ioarilla Apache T·ribe 

Subsurface geologic information from oil and gas 

tests suggests that large supplies of ground water for 

.irrigation could be obtained from wells tapping consolidated Upper Cretaceous and Tertiary rocks in the 

southern part of the Jicarilla Apache Indian Reservation and vicinity, southeastern San Juan Basin, 

N. Mex. In favorable locations yields of as much as 

3,500 gpm (gallons per minute) appear possible; at 

present few wells in northwestern New Mexico yield 

more than 300 gpm. 

T. 

26 

N. 

T. 

25 

N. 

T. 

The southern part of the Jicarilla Apache Indian 

Reservation and the adjacent region to the south and 

east (fig. 171.1) include an area of about 1,300 square 

miles in the east-central part of the San Juan Basin. 

The Upper Cretaceous and Tertiary rocks of this 

region consist of complexly related .sandstone and shale 

facies, which were studied by detailed surface mapping 

and by subsurface correlation based on electric logs of 

wells drilled for oil and gas. The distribution and 

thickness of potential sandstone aquifers were deterEXPLANATION 

~~1~re~J.~~f~ Alluvium 

Colluvium and terrace gravel 

[LJ 

Intrusive igneous 

rocks 

San Jose Formation 

of Simpson (1948) 

Ts4 , upper shale unit 

Ts 3 , upper sandstone unit 

Ts 2 , lower shale unit 

Ts 1 , basal sandstone unit 

Nacimiento Formation 

>-

a:: 

c( 

z 

a:: 

LIJ 

Icc 

::::> 

0 

>-

a:: 

c( 

1-

a::: 

LIJ 

1-

Ojo 

~ Alamo 

Sandstone 

Kirkland Shale and 

Fruitland Formation 

Pictured 

~ Cliffs 

Sandstone 

E3 

Lewis Shale 

Mesaverde Group 

Contact 

p-Area of report 

NEW MEXICO 

(/') 

::::> 

0 

LIJ 

u 

c( 

1-

LU 

a:: 

u 

FIGURE 171.1.-Generalized geologic map of the southern part of the Jicarilla Apache Indian Reservation and vicinity, 

San Juan Basin, N. Mex. 
D174 GEOLOGICAL SURVEY RESEARCH 19 6 2 

mined, and the potential yield of deep water wells in 

the reservation was estimated. 

The oldest rocks mapped are those ot the l\{esaverde 

Group of Late Cretaceous age (fig. 171.1). Other 

Upper Cretaceous rocks mapped include, in ascending 

order: the Le,vis Shale, the Pictured Cliffs Sandstone, 

the undivided Fruitland Formation and IGrtland 

Shale, and the Ojo Alamo Sandstone. The Ojo Alamo 

Sandstone, which ranges in thickness from 70 to 200 

feet, is the deepest aquifer from which large amounts 

of potable water may be expected in most of the area~ 

Rocks of Tertiary age include, in ascending order, 

the Nacimiento Formation, the San Jose Formation 

• ·of Simpson (1948), and several igneous dikes. The 

Nacimiento Formation of Paleocene age ranges in 

thickness from 540 feet in the east-central part of the 

area to 1,750 feet in the north-central part. In the 

southern half of the area, the Nacimiento consists 

mostly of shale with a few intercalated beds of sandstone, and it does not' yield water to wells. In the 

northern half of the area, the Nacimiento consists of 

shale and thick beds of sandstone which yield potable 

\Vater to wells at a few places. These sandstone beds 

locally constitute more than half of the Nacimiento 

Formation and may be feasible sources of large supplies of water from deep wells. 

The San Jose Formation of Eocene age ranges in 

thickness from 200 to 7 50 feet in the southern part 

of the area to 1,800 feet in the northern part. Four 

lithologic units of the San Jose were mapped: a 

basal sandstone unit, mostly conglomeratic arkosic 

sandstone ranging in thickness from 40 to 780 feet ; 

a lower shale unit containing interbedded thick to 

thin sandstone and ranging in thickness from 400 to 

800 feet in the southern part of the area to 1,640 feet 

in the east-central part; an upper sandstone unit, 

consisting mainly of conglomeratic arkosic sandstone 

as much as 1,300 feet thick; and an upper shale UJ;lit, 

consisting of reel shale and interbedded thin to thick 

sandstone. Sandstone beds in all the units of the 

San Jose yield water to wel1s, and the thick sandstones of the basal sandstone unit and the upper 

sandstone unit may be practical sources of large 

amounts of water from deep wells in parts of the area. 

Unconsolidated colluvium and gravel of Tertiary ( ?) 

and Quaternary age cap several terraces and occur in 

stream channels and valleys. These deposits yield 

small· supplies of potable water to wells and springs. 

Alluvial deposits of Quaternary age in the major 

valleys contain small amounts of water ·at many places. 

The principal sources of recharge are precipitation 

and streamflow on outcrops ·of the aquifers in the 

eastern and southern parts of the area, at altitudes of 

7,000 to 8,000 feet. Ground water discharges from 

outcrops at lower altitudes, mainly in the western part 

of the area, but this water is dissipated largely by 

evapotranspiration. Investigations of the flow of the 

San Juan River northwest of the area indicate that 

the increment of ground-water discharge to that river 

is too small to detect. 

Water in the Ojo Alamo Sandstone and the San Jose 

Formation varies widely in chemical quality. Some 

of the water is undesirable for irrigation owing to high 

concentrations of sodium relative to calcium and 

magnesium, and some of the water is undesirable for 

drinking because of a high sulfate content. 

Small supplies of ground water, most of which is 

potable, can be obtained at depths of a few feet to a 

few hundred feet at most places throughout the area. 

Deep water wells have not been drilled, but the potential yield of deep wells will depend largely on the 

cumulative thickness of sandstone penetrated. 

The specific eapacity of 59 wells that tap sandstone 

aquifers in the San Juan Basin, including 8 in the 

area investigated, ranged from 0.0002 to 0.015 gp1n 

per foot of dra wdown per foot of sandstone penetrated. The average was 0.008 for the 8 wells, which 

penetrated only a few feet of saturated sandstone 

in different aquifers in the Ojo Alamo, Nacimiento, 

and San Jose Formations. The total cumulative thickness of sandstone below 200 feet-the assumed average 

depth to the water table-and above the base of the 

Ojo Alamo Sandstone ranges from 80 to 1,840 feet, 

and sandstone n1akes up 10 to 50 percent of the saturated section in 29 wells drilled for oil and gas. 

The total thickness of sandstone in the saturated zone 

above the base of the San Jose Formation ranges 

from a few to 840 feet, and sandstone makes up 20 to 

60 percent of the saturated section. The most favorable place for developing large-capacity deep wells is 

in T. 25 N., R. 5 W., where the section consists of 

50 to 60 percent sandstone. 

Using the average specific capacity per foot of sandstone penetrated ( 0.008) of the 8 weels in the area, the 

calculated potential yield of a well in sec. 25, T. 25 N., 

R. 5 vV., that tapped all the sandstone (600 feet total 

thickness) to the base of the San Jose Formation 

might be expected 'to be as much as 1,400 gpm at a 

dra wdown of 300 feet, and a well that tapped all the 

sandstone ( 1,4 70 feet, total thickness) to the base of 

the Ojo Alamo Sandstone might yield as much as 

3,500 gpm at the same drawdown. These calculated 

potential yields of deep wells warrant test drilling for 

irrigation supplies. 

..,_ 
'-< 

...,, 

ARTICLE 172 D175 

The composite water that would be produced from 

the Ojo Alamo, Nacimiento, and San Jose Formations 

probably would be suitable for irrigation with proper 

soil-management precautions, and would be suitable 

also for n1any types· of industrial uses. 

REFERENCE 

Simpson, G. G., 1948, The Eocene of the San Juan Basin, 

New Mexico: Am. Jour. Sci., v. 246, pt. 1, p. 257-282; 

pt. 2, p. 363-385. 

172. COMPACTION OF THE AQUIFER SYSTEM AND LAND SUBSIDENCE IN THE SANTA CLARA 

VALLEY, CALIFORNIA 

By J. H. GREEN, Sacramento, Calif. 

Land in the central part of the Santa Clara Valley, 

Calif., has been subsiding for many years as a result 

o.f pressure decline in the intensively pumped artesian 

aquifer system (Poland and Green, 1962). About 230 

square miles of urban and agricultural land extending 

fr01n Palo Alto and Niles to San Jose subsided at 

rates up to 0.3 foot per year between 1954 and 1960. 

Periodic releveling of bench marks throughout the area 

indicates two "bowls" of maximum subsidence since 

1912; Sunnyvale, with a subsidence of 11 feet and 

s~-tn Jose, 7.4 to 9 feet. The subsidence is due to 

compaction of the aquifer system, which takes place 

as overburden· load is transferred from the water to 

the sediments of the aquifer system as the artesian 

pressure is depleted. 

Two 1,000-foot core holes were drilled in 1960, one 

at each center of maximum subsidence. Compaction 

recorders, of the type described by Lofgren ( 1961), 

were installed in these and other wells of shallower 

depth to measure the compaction within the deposits. 

The field installations show that the measured compaction .is comparable to the observed subsidence. 

Results' of laboratory tests on cores, and records of 

changes in artesian pressure since 1915, were used to 

compute the compaction in the water-bearing deposits. 

The purpose of this article is to outline the procedure 

for computing the compaction, to present the results 

of the c01nputntion, and to compare cori1puted compaction with subsidence observed from. precise leveling. 

METHOD OF COMPUTATION 

The procedure for computing· the compaction of 

aquifer systems as a result of water-level decline has 

been described more fully by Miller (1961), and is 

based on Terzaghi's theory of consolidation (1943). 

The total thickness of unconsolidated deposits affected by the pressure decline is subdivided, on the 

basis of interpretation of electric logs, into a reasonable number of. zones of relatively uniform lithology. 

For each zone a one-dimensional consolidation test is 

made of a representative core sample. Using values 

of specific gravity and dry density determined in the 

Denver I-Iydrologic Laboratory of the Geological Survey, the effective overburden stress (grain-to-grain 

load) on each zone is computed for several periods of 

artesian-pressure change. The comp~ction of each 

lithologic zone is then computed, using these values 

of effective stress, and using laboratory consolidationtest data for the same range of loads determined by the 

Earth Laboratory, U.S. Bureau of Reclamation, Denver, Colo. 

The compaction that occurs in each zone is computed 

from the relationship 

Am= eo-el 1

n 

1 +eo ' 

in which ~ 1n = compaction, in feet, 1n = thickness of 

zon~, in feet, and e0 and e1 are initial and final void 

ratios. The total aquifer compaction is equal to the 

sum of compaction of all zones subject to increase in 

effective stress. 

In fine-grained deposits, compaction (and subsidence) 

does not take place immediately as the effective stress 

increases. In relatively impermeable clayey zones, 

many years may be required before escape of water 

permits the internal fluid pressure to reach equilibrium 

with that in contiguous beds of more permeable sand 

and gravel, which adjust quickly in response to pressure changes. Furthermore, a thick clayey zone containing thin sand stringers will compact more quickly 

than an equally thick clayey bed without interbedded 
D176 GEOLOGICAL SURVEY RESEARCH 19 6 2 

sand stringers, because the more permeable interbeds 

permit quicker escape of water from the clayey segments. The percentage of ultimate compaction for 

a specific number of years may be estimated by utilizing the consolidation coefficient (determined as part 

of the consolidation test) and Terzaghi's (1943) equation and graphs for computing compaction time. 

Residual compaction, which results in lag of subsidence, is the ultimate computed compaction less the 

percentage of computed compaction for that number 

of years. The reliability of tl?-e computation of residual compaction depends largely on how representative the tested consolidation sample is of the entire 

lithologic zone. The total compaction computed for 

any load change should equal the land-surface subsidence for that same period of time. Thus the reliability of the computed compaction can be checked . 

In areas where precise leveling data are available. 

COMPACTION AT CORE HOLE 6S/2W-24C7 

The table below shows the effective loading and 

cq.mputed compaction at core hole 6S./2W-24C7, at 

Sunnyvale. 

The artesian system was divided into nine zones, 

each of relatively uniform lithology. The clay bed 

confining the artesian system lies between the depths 

of 150 and 185 feet, thus all compaction was assumed 

to occur in the 7 zones below 185 feet. It is only 

below the confining bed that the effective load varies 

owing to changes· of artesian pressure. 

The artesian-pressure decline used for the computations in the table was that recorded at well 6S/ 

2W -25Cl, 500 · feet deep and about a mile south of 

the core hole. Cumulative effective loading on the 

individual zones was computed from this pressure 

decline for the years shown in the table, and for the 

ultimate effective load, assuming an artesian-pressure 

decline to atmospheric (depth to water, 185 feet) at 

some future date. 

Effective loading and computed compaction at core hole 6Sj2W24C7 

Zone 

depth 

(feet) 

Effective load (psi) Compaction (ft) 

Ulti- Lag as 1960- 1915 1934 1954 1960 mate 1 1915-34 1934-54 1954-60 of 1960 ultimate I 

----1---------------------

0-ll'iO ______ ----- _____ ----- ----- ______________________ -------- -------- __ · ___ _ 

150-185______ 129 129 129 129 129 -------- -------- -------- -------- ------ 185-215 ______ 79 123 125 130 159 0.70 0.04 0.08 0.01 0.36 215-415______ 93 137 139 144 173 3. 40 1. 11 . 37 1. 01 2. 6 415-550 ______ 184 228 230 235 264 1.06 .45 .17 .49 1.1 550-680 ______ 248 2!)2 294 299 328 . 40 . 22 . 06 1. 17 . 92 680-800 ______ 309 353 355 36~ 389 1. 04 . 29 .12 .18 . 91 800-905 ______ 362 4\6 408 413 442 . 84 . 20 .. 08 .12 . 60 905-1,000 ____ 411 455 457 462 491 .20 .11 .01 .57 .48 

TotaL ----- _______________ ------ 7. 64 2. 42 . 89 3. 55 6. 97 

I Computed for artesian-pressure reduction to atmospheric pressure at base of 

confining layer (185 feet). 

Because the deposits at core hole 6S./2vV -24C7 are 

chiefly fine grained and relatively impern1eable, compaction lag ·was evaluated for each zone. Three zones 

containing sandy interbeds were divided into several 

segments (not shown in table) for computation of 

compaction lag. 

Compaction of each zone was computed for the 

periods shown; the lag in subsidence was computed 

as the residual compaction as of January 1960. If the 

artesian pressure remained at the January 1960 level, 

the computation indicates that the area eventually 

would subside an additional 3.5 feet. If, in the future, 

the artesian pressure should decline to atmospheric, 

the computed additional subsidence would amount to 

about 7 .feet. Therefore, subsidence after 1960 may 

eventually total as much· as 10 or 11 feet. 

Figure 172.1 compares the total computed subsidence 

and the computed subsidence, less lag, at core hole 

6S/2W -24C7, for the periods 1915-34, 1934--54, and 

1954-60; the actual subsidence of a nearby bench 

mark; and the hydrograph for well 6S/2W-25Cl. 

Releveling of bench marks by the U.S. Coast and 

Geodetic Survey furnished the evidence on land subsidence. Bench mark Jlll Reset is only a few hundred 

feet from the core hole. Subsidence of this bench 

mark since 1934 is plotted on figure 172.1. The sub:-

sidence shown from 1912 to 1934 at Jlll Reset was 

estimated from a proportional plot of subsidence at 

bench mark M7,I about 3 miles southeast. 

The hydrograph of figure 172.1 is generalized and 

shows only the high-water level for each year of 

record. This simplified form is adequate to illustrate 

1najor changes in artesian pressure and to aid in the 

analysis of bench-mark subsidence. High-water levels 

for the years 1915, 1934, 1954, and 1960 were used to 

compute subsidence. 

The rate of subsidence and water-level decline prior 

to the early 1930's probably was not uniform, as shown 

in figure 172.1, but data were not available for intermediate control. However, the downward trend of 

water levels in the Santa Clara Valley started about 

1917. 

A comparison of the total calculated subsidence 

and the calculated subsidence, less lag, in figure 172.1 

shows the estimated amount of lag in subsidence remaining in the aquifer system as of 1934, 1954, and 

1960. The estimated time required for the ultimate 

subsidence to occur after 1960, if artesian pressure 

stayed at the 1960 level, would be about 350 years. 

1 Bench mark M7 was established in 1912, whereas J111 Reset was 

not established until 1934. The leveling record for these bench marks 

overlapped· for 2 years between 1934 and 1936. During this time, 

J111 Reset subsided at a rate 2.5 times that of M7. This proportion was applied to M7 for the period 1912-34 and assumed to be 

the approximate subsidence of J111 Reset. 
-~-

0 

2 

t; 4 1£.1 

"-

.... ·~ 

" 

slJb . 

~ . . 

"'~-..... ..... 

ARTICLE 172 D177 

0 

20 

Reser ,, .. -' 

.... .... ....• '·-- I 

40 ~ 1£.1 

"-

~ lila, .4 ~ 

........ ~~/)~ ....... 4 ,.,1! ......... ~ I''-. -~" . less lag ,~" 

60 

ri 

1£.1 

~ 6 

ri ······;_ ...... LJ 

0 8 z 

1£.1 

........ " ........ .. -,-r------ \ 

~ ·······,.··· 

80 i 

0 e 1o en 

CD 

:;) " ' .. .... ... \ 

~ 

~ .- ... 

•• ~ .• ~·· •, J!A. ~" 

100 ~ 

J: 

~ 

~ _fomputed ~i~~ ..!2!!L - • 1_20 f!i 

0 

en 12 

---..... -- -..... 14 140 

16 160 

1915 1920 1925 1930 1935 1940 1945. 1950 1955 1960 

FIGURE 172.1.-Computed and actual subsidence at core hole 68/2W-24C7 and hydrograph of nearby water well. 

Calculat-ions indicate that more than half this amount 

would occur in the first 7 5 years. 

A comparison of actual subsidence at bench mark 

J111 Reset with the hydrograph of well 6S/2W-25C1 

shows the rate of subsidence to be greater in periods 

of steep water-level decline than in periods of waterlevel rise. The recovery of artesian pressure between 

1935 and 1943 acted to decrease the rate of subsidence 

to less than half that of the 1912-34 period. However, 

s01ne subsidence continued, indicating that internal 

fluid pressure in the thickest beds of low permeability 

still exceeded the recovered artesian pressure in the 

n1ore permeable beds during at least part of the 1935-

43 period. As shown in figure 172.1, subsidence resumed at about the pre-1934 rate in 1948 when the 

artesian pressure was drawn down below its prior 

low (1934 level). 

Figure 172.1 shows that c01i1puted subsidence, less 

lag, compares favorably with actual subsidence at 

bench mark J111 Reset. Computed subsidence, less 

0 

~ 2 

1£.1 

"-

~ 3 

~···· 

~ 

··~(J6 ··.!icte 

!f.J IP/!c :J-. • 

~0 ~it 

~ ~,.e~..;.. 

r,./1~ ... ~,.,9 

.... 

' -~-~ ~-- " 'o.: ..... e'><',. ......_ .. 

lag, for the period 1915-60 is 10.95 feet, whereas 

actual subsidence \vas 10.98 feet. 

COMPACTION AT CORE HOLE 7S/1E-16C6 

Similar computations were made for core hole 7S/ 

1E-16C6, in the city of San Jose. The stratigraphic 

section was divided into 16 zones; artesian confinement was assumed in the zones below 245 feet. The 

wp,ter-level record for a well 800 feet deep and only 

a few feet from the core hole was used for the artesianpressure change. 

Figure 172.2 shows computed subsidence at core hole 

7S/1E-16C6 for the periods 1915-34, 1934-54, and 

195~60; also subsidence of a nearby bench mark, and 

the hydrograph for well 7.S/1E-16Cl. Interpretations 

and computations were made on the same basis as for 

core i1ole 6S/2"V -24C7, except that compaction lag 

was considered to be negligible on the basis of consolidation tests. Computed subsidence for the period 

5 

-f/ \ 25 

I ~ • I ... -

I \ 

'JI ", 

~ 45 1£.1 

"-

65 ~ 

ri 

1£.1 ti 4 

z 

1£.1 

.,'?of.' 'e.-· 

., .. ..... ~. .............. ' ········• 

85 ~ 

~ 

e 5 en 

CD 

:;) 

en 6 

7 

8 

1915 1920 1925 

.......... ·, _.._ .. 

~ 

1930 1935 1940 1945 

i.'• .. "''e ,~·· .. ~,...· ... \. ,.\ l't 

'w •• -..~' ll \ .. t --.... - ··. --...:.:.j •• 

105 ~ 

J: 

.... 125 f!i 

0 

145 

1950 1955 1960 

165 

FIGURE 172.2.-Computed and actual subsidence at core hole 7S/1E-16C6, and hydrograph of nearby water well. 
Dl78 GEOLOGICAL SURVEY RESEARCH 19 6 2 

1915-60 was 7.6 feet, whereas subsidence of bench 

mark Al49, nearby, determined from leveling by the 

U.S. Coast and Geodetic Survey .was 7.1: feet. 

REFERENCES 

Lofgren, B. E., 1961, Measurement of compaction of aquifer 

systems in art:as of land subsidence : Art. 24 in U.S. Geo1. 

Survey Prof. Paper 424-B, p. B49-B52. 

Miller, R. E., 1961, Compaction of an aquifer system computed 

from consolidation tests and decline in artesian head: 

A1·t. ~26 in U.S. Geol. Survey Prof. Paper 424-B, p. B54-

B58. 

Poland, J. F., and Green, J. H., 1962, Subsidence in the Santa 

Clara Valley, California-a progress report: U.S. Geol. 

Survey Water-Supply Paper 1619-C, 16 p., 12 figs. 

Terzaghi, Karl; 1943, Theoretical soil mechanics: New York, 

John Wiley & Sons, 510 p. 

SURFACE JfATER 

173. USE OF SHORT RECORDS OF RUNOFF TO ESTIMATE A 25-YEAR AVERAGE RUNOFF IN THE POTOMAC 

RIVER BASIN 

By WILLIAMS. EISENLOHR, JR., Denver, Colo. 

The accompanying table can be used to estimate 

average annual runoff in the Potomac River basin for 

the period 1931-55 from short streamflow records of 

that period. It was computed as part of the preparation of a runoff map of the Potomac River and smaller 

basins interjacent to Delaware Bay. To use the table, 

Cumulative annual runoff, in percent of the total runoff for the 

period 1931-55, for regions A, B, and C 

Region Region Region Water Water Water 

year year year A B c A B c A B c --- - ------ - ------ - - 1931__ ___ 2. 4 1.2 1. 8 1940 _____ 39.2 39.0 37.8 1948 _____ 68.2 68.2 69.4 1932 _____ 5. 5 3.3 4.0 1941_ ____ 42.0 . 42.0 41.1 1949___-- 74.3 74.5 73.8 1933 ___ -- 10.5 9.0 10.1 1942 ___ -- 45.3 44.5 45.3 1950 ___ -- 78.3 78.2 77.4 1934 ___ -- 12.6 12.4 13.1 1943 ___ -- 51.0 49.4 50.4 195L ___ 83.7 83.2 83.1 1935 ___ -- 17.5 17.2 17.1 1944 ___ -- 54.1 52.4 53.9 1952 ___ -- 88.2 88.8 88.9 1936 _____ 23.0 22.2 22.1 1945 ___ -- 58.1 56.7 57.8 1953 _____ 92.4 94.5 94.3 

1937----- 27.8 27.7 27.0 1946 ___ -- 61.9 61.2 62.4 1954__ ___ 94.7 96.7 96.5 

1938 ---- 31.5 31.9 30.4 1947 ___ -- 64.3 63.8 65.5 1955.._ -- 100.0 100.0 100.0 1939 _____ 35.3 35.6 33.9 

one needs only to determine by subtraction, for the 

proper region (fig. 173.1), the tabular value of cumulative annual runoff, in percent, for the period o£ record 

available an divide 0.25 times that value into the 

amount of runoff, in inches, observed during complete 

water years of record to obtain the estimated average 

annual runoff for 1931-55. 

For example, the total runoff of Cacapon River at 

Yellow Spring, W. V a., in region A, was 136.68 inches 

for the 12 water years 1940-51. From the table, 

runoff in region A during these 12 years was 48.4 

percent ( 83.7-35.3) of the 2q-year total runoff. The 

38" 

0 50 100 MILES 

FIGURE. 173.1.-Map of Potomac River, basin and smaller basins interjacent to Delaware Bay, showing regions A, B, and 

C (heavy lines) described in text. (Dashed-and-dotted lines 

are boundaries of drainage basins.) 

25-year average runoff is then estimated as 136.68/ 

(0.25 X 48.4), which equals 11.3 inches per year. This 

record was chosen as the best one to illustrate the 

method; n1ost records require a much larger adjustment. 

The table was computed in the following manner. 

In and near the Potomac River basin and smaller 

basins interjacent to Delaware Bay there are 27 streamgaging stations for which (a) the records of streamflow are complete for the water years 1931-55, (b) the 

,_ 

t 
I 

.... 

. ! 

ARTICLE 174 D179 

WATER YEAR 

1!"''muuE 173.2.-Annual runoff in regions A, B, and C shown as 

cumulative dej:mrture from average, in percent of total runoff, for the period 1931-55. 

drainage areas are more than 5 square miles but 

less than 1,000 square miles, and (c) effects of 

manmade regulation and diversion can be eliminated. 

A plot of the cmnulative departures of annual runoff 

from the average annual runoff for the 25-year period, 

expressed in percent of total runoff, showed remarkably little variation among the records. There was 

enough variation, however, that it was considered 

best to divide the area into three regions. The plotted 

departures for each gaging-station record were cOinpared separately with sketched plots of: tentative regional averages (such as shown in fig. 173.2) to determine the regional classification of the station. Regional averages were then computed on the basis of 

this classification. A single repetition of this process 

was sufficient to assure that each record was classified 

properly, and then the outlines of the regions were 

drawn as shown in figure 173.1. 

The cumulative departures of annual runoff from 

average runoff for each region are plotted in figure 

173.2. Approximately horizontal lines indicate average runoff whereas steeply sloping lines indicate runoff either much greater or much less than average. The 

departures from average runoff are almost wholly the 

result of differences in weather from year to year. The 

effects of such basin characteristics as t9pography, 

geology, and vegetation appear in the 25-year runoff 

and are thus almost eliminated insofar as they affect 

runoff, although the effect of vegetation varies slightly 

with pi.·ecipitation. 

The standard errors of estimate of the points used 

to define the regional curves in figure 173.2 (with loss 

·of 25 degrees of freedom-one for each year's average) 

were found to be: Region A, 0.6 percent; region B, 

0.6 percent; and regimi. C, 0.5 percent. This means 

that about two-thirds of the points lie closer to the 

curve they define than the sta~ed values of percent of 

total runoff for the period 1931-55 . 

174. USE OF REGIONALIZED FLOOD-FREQUENCY CURVES IN ADJUSTING FLOW-DURATION CURVES 

By G. A. ICIRKPATRICK and J. A. McCAnE, Louisville, Ky. 

As part of an intensive study of water resources in _.River, Tygarts Creek, upper Licking River, upper 

the Eastern Coal Field of ICentucky, duration curves 

of daily flow have been prepared from records of 

streamflow at gaging stations in the region. Because 

flow-duration curves based on short periods of record 

are unreliable for predicting the future pattern of 

flow, all curves in the Eastern Coal Field are being 

adjusted to represent a long-term base period. These 

adjusted curves can be defined at the upper end by, usb 

of regional flood-frequency curves. 

The Eastern Coal Field covers about 10,400 square 

1niles of the eastern part of ICentucky. Within this 

region are parts of the ICanawha, Cumberland Plateau, 

and Cumberland ~{ountain sections of the Appalachian 

Plateaus physiographic province. Principal stream 

basins are those of the Big Sandy River, Little Sandy 

ICentucky River, and upper Cumberland River. The 

upper Cumberland River, Rockcastle River (a tributary of Cumberland River), and the South Fork of 

Cumberland River are particularly referred to in this 

article. 

A flow-duration curve is a cumulative-frequency 

curve that shows the percentage of time during which 

specified discharges are equaled or exceeded (Searcy, 

1959, p. 1). Duration curves of daily flow referred to 

herein are computed from figures of daily mean flow 

for all complete water years of streamflow record. 

The method used to adjust curves prepared from 

short-term .records to represent curves from longterm records is sometimes called the index-station 

method (Searcy, 1959, p. 12). A relation is estab-
D180 GEOLOGICAL SURVEY RESEARCH 19 6 2 

lished between the index station and a short-term station for the short period of concurrent record by 

plotting a graph of the discharges for given durations 

at one station against the corresponding discharges at 

the other station. This graph is assumed to represent 

the relation between stations for a long period as well 

as for the short period from which it is drawn. The 

discharges for various percentage-duration values at 

the long-term index station are applied to the graph 

to determine the adjusted discharges for the corresponding percentage-duration values at the short-term 

site. 

For this method to be valid, both the index station 

and the short-term station must be influenced by similar weather conditions. That similar conditions generally exist in the Eastern Coal Field is substantiated 

(f) 

z 

0 

f= 

<( 

1-

Cfl 

~ 100 

(; 90 <( 

Cl 

>-

~ 70 <( 

. ~ 60 

1-

<( 50 

I.LI 

...J 

::2: 40 I.LI 

0::: 

<( 

:J 

0 

(f) 

0::: 

I.LI 

a.. 

0 

z 8 20 

I.LI 

(f) 

0::: 

I.LI 

a.. 

1-

I..LI 

I.LI 

LL 

~ 

IIl 

:J 

u 

z 

LJ 

Cl 

0::: 

<( 

I 

u 

(f) 

0 

10 

9 

8 

7 

6 

5 

EXPLANATION 

• 0 

Rockcastle River 

at Billows, Ky -:----. /:::, Cumberland River 

at Barbourville, Ky 

---. D 

South Fork Cumberland 

River at Stearns, Ky 

<~ ~ ~ )U ~ 

0. 7 

..... 

c 

~' 

h /7 

6 7 8 9 10 20 30 

DISCHARGE, IN CUBIC FEET PER SECOND PER SQUARE MILE, 

CUMBERLAND RIVER AT CUMBERLAND FALLS, KY 

FIGURE 174.1.-Curves of relation between streamflow at gaging station Cumberland River at Cumberland Falls, and flow 

at three nearby stations. Solid symbols show ·discharge at 

equal-percentage duration; open symbols show peak discharge at recurrence intervals of 10 and 50 years. 

by the satisfactory correlations of streamflow at one 

gaging station with that at other stations. The coefficient of correlation of monthly mean discharges 

between the Cumberland River at Cumberland Falls 

and 13 other gaging stations in the upper Cumberland River basin ranges from 0.72 to 0.98. Only two 

of these coefficients are less than 0.84. 

Above its low-flow end, the relation curve between 

discharges at pairs of gaging stations is generally near 

to or· converges toward the equal-yield line, because 

storm runoff predominates at high flow, and base runoff, which is affected by geologic conditions, is a negligible part of the total flow. The equal-yield line 

defines the relation curve ·when flow at the two sites 

is proportional to the respective drainage areas above 

the sites. If the shape and slope of the basin upstream 

from one gaging station are such that the effect of 

storm precipitation is distributed over an extended 

time period, and if storm runoff from the other basin 

is concentrated in a much shorter time period, the line 

of discharge relation deviates from the equal-yield 

line toward the coordinate scale for the station with 

less retention (see fig. 17 4.1). For high daily discharge::; the ratio of maximum daily discharge· to peak 

discharge tends to become constant for each gaging 

station as implied by the unit hydrograph theory. 

Thus, at high discharges the relation line between 

daily discharge tends to become parallel to the equalyield line in approximately the same position as the 

relation line between peak discharges. 

Curves relating the flow of the gaging station 

Cumberland River at Cumberland Falls, Ky., to the 

flow .at three other gaging stations in the upper Cumberland River basin are shown in figure 174.1. These 

gaging stations with their respective drainage areas, 

flood regions and hydrologic areas of Kentucky in 

which they are located and the number of years of 

record used with the concurrent record for Cumberland River at Cumberland Falls are given below. 

Station name 

Cumberland River at Cumberland Falls_ 

South Fork Cumberland River at Stearns _______________________ · ___ _ 

Rock castle River at Billows __________ _ 

Cumberland River at Barbourville ____ _ 

I See text below for explanation. 

1, 977 B 

954 B1 

604 B2 

960 B2 

14 

20 

13 

The flood region indicated by the letter B in the 

preceding table, and the hydrologic area within the 

region indicated by the numeral following the letter, 

are defined by a regional flood-frequency analysis for 

l{entucky streams being conducted by the junior author using methods described by Dalrymple ( 1960, 

l 

~ 
,... .. 

ARTICLE 174 D181 

""' ..J 

i 

""' a: 

< 

::I 

0 

200 

t/J 100 

a: 

""' Q. 

0 

z 

0 

~ 60 t/J 

ffi 50 Q. 

~ ""' 40 LL. 

(.) 

a; 

::I 30 (.) 

~ 

u.i 

e,· 

a: 

< 

J: 

(.) 

t/J 

0 

-.._ 

-------"Year 2 f.l ____ oo

0 

-----------

300 

DRAINAGE AREA, IN SQUARE MILES 

FIGURE 174.2.-Variation of 2-, 10-, and 50-year floods in 

flood region B, J{entucky. Solid lines are for hydrologic 

area 1 and dotted lines for hydrologic area 2, as defined by 

a flood-frequency analysis. 

p. 25-46). The position of the upper ends of the relation curves shown in figure 17 4.1 have been defined 

by using the results of this regional flood-frequency 

analysis. The analysis gives graphs whereby an annual flood for a selected recurrence interval may be 

determined for a given site if the drainn,ge area of the 

site is known. Regionalized flood-frequency data, 

rather than single station data, are used to define adjusted flow-duration curves, because evidence indicates 

that a flood-frequency graph that is based on the combined records of a group of st~tions has firmer support 

than one drawn to fit the. data of a single . station 

(Dalrymple, 1960, p. 65). 

An example of the information available in the 

junior author's analysis is shown in figure 174.2. The 

curves therein show the variation of annual floods of 

selected recurrence intervals with drainage area. A 

50-year flood is a flood that is equaled or exceeded once 

in a period of time that averages 50 years, or -one that 

has a 2-percent chance of being exceeded in any year. 

Likewise, a 10-year ·flood is a flood that is equaled or 

exceeded once in a period of time that averages 

10 years, or one that has a 10-percent chance of being 

exceeded in any year. The plotting positions of the 

10- and 50-year floods shown in figu~e 174.1 for the 

gaging stations South Fork Cumberland River at 

Stearns, Rockcastle River at Billows, and Cumberland 

River at Barbourville are picked from the curves 

shown in figure 174.2. The plotting positions for the 

gaging station Cumberland River at Cumberland 

Falls, a main-stem station, are from a flood-frequency 

curve of the flood peaks observed at the station. 

Twenty-four relation curves similar to those shown 

in figure 174.1 have been prepared using 7 additional 

gaging stations in the upper Cumberland River basin, 

6 gaging stations in the Big Sandy River basin, and 

7 gaging stations in the upper l(entucky River basin. 

These relations strongly indicate that the peak discharges having an average recurrence interval of 

10 years define a point that lies very close to a point 

on the flow-duration relation curve above which the 

curve tends to become parallel with the equal-yield 

line. Relation curves drawn through this· point, as 

illustrated in figure. 174.1, are usually better than 

curves defined only by the higher equal-percentage 

duration points. 

Reference to figure 174.1 shows that the relation 

. curve for South Fork Cumberland River at Stearns 

could have been drawn nearly as well without the 

flood-frequency data. The upper end of the curve for 

Rockcastle River at Billows would have been drawn 

above its proper position, and that for Cumberland 

. River at Barbourville would have been drawn too low. 

The use of flood-frequency data in this manner helps 

in defining the relation between those stations having 

only a few years of concurrent record, because points 

of equal-percentage duration plot more erratically as 

the length of concurrent record becomes less. Such 

data also help if a longer period of concurrent record 

has no hi.gh flow, because the relation. curve would 

then need to be extrapolated before it could be used 

in adjusting the short record to the long-term base 

period. 

REFERENCES 

Dalrymple, Tate, 1960, Food-frequency analyses: U.S. Geol. 

Survey Water-Supply Paper 1543-A, 80 p. 

Searcy, J. A., 1959, Flow-duration curves: U.S. Geol. Survey 

Water-Supply Paper 1542-A, 33 p. 
D 182 GEOLOGICAL SURVEY RESEARCH 19 6 2 

175. A CONTROL STRUCTURE FOR MEASURING WATER DISCHARGE AND SEDIMENT LOAD 

By E. V. RICHARDSON and D. D. HARRis, Fort Collins, Colo., and Denver, Colo. 

A control structure ~as designed for the Rio Grande 

conveyance channel near Bernardo, N. Mex., to stabilize the stage-discharge relation and to facilitate the 

measurement of the total sediment load. With modification for various site conditions the control should 

be suitable for installation on other sand-channel 

streams to improve their water and sediment-discharge 

records. The stage-discharge relation for the conveyance channel is very unstable, as it is for many other 

sanc;I.-bed streams (Colby, 1960; Dawdy, 1961). The 

stage may change 1 to 3 feet without a change in discharge or, conversely, the discharge may change without a change in stage. The proposed control provides 

for the determination of the total sediment discharge, 

whereas with no control only the suspended sediment 

would be measured. The design of the control was 

based on a model study and observed channel conditions. 

Two factors contribute to the unstable stage-discharge relation in a sand-channel stream: changes in 

the mean elevation of the channel bed, and changes in 

the configuration of the bed. Either one or both of 

these changes can occur with or without a change in 

the water discharge. In the conveyance channel the 

mean bed elevation varies about 4 feet. An increase in 

discharge is usually accompanied by an increase in bed 

elevation, and a decrease in discharge by a decrease in 

bed elevation. 

The effect of changes in bed configuration on the 

depth-discharge relation is illustrated in figure 175.1. 

The variation in the depth-discharge relation is caused 

by the bed configuration changing from dunes, which 

occur at low flows and which have a large resistance 

to flow, to a plane bed, which occurs at high flows and 

has a much lower resistance to flow. The stage-discharge relation for a sand-channel stream is subject 

to this variation of the depth -discharge relation as 

well as to the variation due to changes in mean bed 

elevation. 

The conveyance channel is about 80 feet wide, and 

its bed and banks are composed of fine sand (median 

diameter 0.24 rrim). Maximum flow is about 2,000 cfs 

(cubic feet per second) , median flow is 280 cfs, and 

the flow exceeds 1,000 cfs 16 percent of the time. Flow 

in excess of 2,000 cfs is carried by the natural river 

channel. The bed form is characterized by dunes for 

discharges up to 500 cfs, changjng to a plane bed at 

discharges between 500 and 1,200 cfs, although dunes 

have been observed for flows as large as 2,000 cfs and 

1-

UJ 

UJ 

..... 

7~~----~----~----~----~~----r7--~.~ 

~ 4~4------+----~,4----+A----~-----+~,-~ J: 

t 

UJ 

0 

300 600 900 1200 1500 1800 

DISCHARGE, IN CUBIC FEET PER SECOND 

FIGURE 175.1.-Depth-discharge relation for the conveyance 

channel. Plotted points are from discharge measurements 

made when bed configuration was characterized by dunes 

(solid circles) , by a plane surface (open circles), or in 

transition (triangles) . 

a plane bed for flows as small as 200 cfs. A combination of a high bed elevation and a dune bed configura-

. tion has caused the channel to flow bankfull (gage 

height 9.5 feet) at a discharge of 2,100 cfs. 

A model study was conducted at Colorado State 

University to devise a control structure that would 

improve the water and sediment-discharge records for 

the channel. The objectives of the model study were 

to (1) determine the shape of a control that would 

stabilize and increase the sensitivity of the stage-discharge relation, ( 2) determine the maximum elevation at 

which the control could be placed in the channel without restricting the bankfull flow to less than 2,000 cfs, 

( 3) determine the best method of controlling any 

scour that the control might create, and ( 4) provide 

a suitable place for measurement of water and sediment discharge. 

Several shapes were studied as two-dimensional 

models ( 1 :8 scale ratio) in a sand-bed flume 2 feet 

wide and 60 feet long. The most promising shape 

·was then modeled ( 1 :10 scale rat!o) and modified in 

a sand-bed flume 8 feet wide and 150 feet long. In 

this study the discharges were modeled using the 

Froude criterion ( Qr = Lr512 where Qr is the dis-
t 

I 

"'-· 

ARTICLE 175 D183 

~ Flow 

.---- Cutting .surface a 

Cutting surface d 

FIGURE 175.2-Details of the proposed control structure. 

charge ratio and L1. is the length ratio), and flume 

slopes were varied so that the bed material moved 

and either a dune or plane bed confi.guration developed. 

The design for the control structure for the conveyance channel was based on the model study and is 

illustrated in figure 175.2. The baffles indicated on the 

figure were installed to prevent the deposition of sediment on the control by increasing the turbulence of the 

flow. As illustrated in figure 175.3, the stage-discharge relation for the model control was affected only 

slightly by the sediment load or by the changes in the 

bed configuration. The desired sensitivity of the 

stage-discharge relation for the control was a 1.5-percent change in discharge for a 0.01-foot change in 

stage. In the study of the model, however, which had 

a transverse crest slope of 40:1, the change in discharge was less than 1.5 percent for each 0.01-foot 

change in stage, for discharges greater than 400 cfs. 

Below 400 cfs the sensitivity decreased so that at 30 

cfs the change in discharge for a 0.01-foot change in 

stage was 7 percent. For the proposed structure (fig. 

175.2), a transverse crest slope of 35:1 was used to 

improve the sensitivity of the stage-discharge relation. 

Slopes steeper than 35 :1 are not recommended because 

in the model study they caused large waves over the 

control and excessive erosion downstream. 

The model control has a stable stage-discharge relation at all discharges, but the prototype control will 

not. The low bankfull stage limited the design eleva-
D184 GEOLOGICAL SURVEY RESEAR!CH 19 6 2 

1-

Lt.l 

LtJ 

u.. 

~ 2~~----~----~~~--~----~------r-----~ u.i 

~ 

c( 

~ 

300 600 900 1200 1500 

DISCHARGE, IN CUBIC FEET PER SECOND 

FIGURE 175.3.-Stage-discharge relation for the modef control. 

Solid circles indicate that bed configuration was characterized by dunes; open circles, by a plane surface. Stage is 

measured at the low point on the control 4 feet upstream 

from the crest. 

tion of the prototype control to 4.5 feet below bankfull stage or 0.5 feet above maximum bed elevation. 

As a result, downstream variation in the tailwater 

elevation will cause variable subrp.ergence. Tailwater 

elevations estimated frmn the prototype stage-discharge relation indicate that free fall (less than 70-

percent submergence) should exist for all discharges 

up to 1,100 ,cfs under average conditions. With maximum observed tailwater elevations, free fall would 

exist only for flows up to 300 cfs. For discharges of 

2,000 cfs the control will be completely submerged, 

regardless of the tail water conditions, and will not 

restrict the maximum capacity of the ·channel. An 

auxiliary gage could l?e used downstream in the conveyance channel to determine the degree of submergence and thus improve the discharge. records. On 

streams where the elevation of the control crest is not 

.limited, the crest elevation could be made high enough 

to eliminate the effect of variable submergence on the 

stability of th~ stage-discharge relation. 

The model study indicated that for transverse slopes 

no steeper than 35:1, excessive downstream scour in 

the prototype can be prevented if a sill 1.5 feet high 

is placed at the downstream toe of the control with its 

crest at, or slightly below, low-bed elevation. In a 

field installation, however, some riprapping of the 

banks and bed near the sill may be necessary. 

The proposed control structure provides for the 

measurement of both the water discharge and the total 

sediment concentration. Velocity profiles obtained in 

the model study indicate that accurate measurements 

of water discharge can be made at a section 9 feet upstream from the crest. The total sediment concentration can be measured along the fillet, which is located 

on the downstrean1 apron (fig. 175.2), by traversing a 

conventional sampler through the entire depth of flow. 

REFERENCES 

Colby, B. R., 1960, Discontinuous rating curves for Pigeon 

Roost and Cuffawa Creeks in Northern Mississippi: U.S. 

Dept. Agriculture, ARS 41-36. 

Dawdy, D. R., 1961, Depth-discharge relations of alluvial 

streams-discontinuous rating curves: U.S. Geol. Survey 

Water-Supply Paper 1498-C, 16 p. 

~· 

., 
ARTICLE 176 D185. 

176. USE OF A RADIOISOTOPE TO MEASURE WATER DISCHARGE 

By B. J. FREDERICK; c. vV. REcK, and R. w. CARTER: Oak Ridge, Tenn.; Washington, D.C. 

·work done in COO]Jet·ation with the U.S. Ato·mic Energy Oommis8ion 

Laboratory tests were conducted to evaluate the use 

of radioisotopes in the dilution method of flow mea-. 

surement. The rate of flow in a 2-inch pipe 120 feet 

long was measured volumetrically and compared with 

the rate of flow computed by measuring the radioactivity of a concentrated solution of radioactive gold 

(Aul9B). 

In the dilution method of flow measurement a solution with a high concentration of radioactivity is injected into the flow at a constant rate, and samples are 

withdrawn at some point downstream where the concentrated solution has completely mixed with the flow. 

According to the principle of continuity, the following 

relationship exists: 

(1) 

in which 

Q=discharge through the pipe, in cubic feet per second; 

q=discharge frmn injection system, in cubic feet per 

,· second; 

00 =concentration of radioactivity in the discharge pipe 

upstream from injection, ·in microcuries . per 

cubic foot; 

t- 01=concentration of radioactivity in injection system, 

in Inicrocuries per cubic foot; and 

0 2=concentration of radioactivity in discharge pipe at 

.. sampling point, in n1icrocuries per'cubic foot. 

As q is very small con1pared to Q, the q02 terrn can be 

neglected, and as Oo is very small compared to 02, the 

,. QOo tern1 can be neglected. Consequently equation 1 

can be reduced to 

(2) 

In these tests the constant injection rate was obtained fr01n the gravity-feed system shown in figure 

176.1. The flow rate q was controlled by the valve 

and wae measured by the volume displaced per unit of 

time. 

Samples were taJ\:en from the pipe at a location 120 

feet downstream ,from the point of injection and transferred to a special container for the detection of radioactive concentration. The sample size was 37 liters 

( 9.8 gallons). The count rate was determined with a 

counter as shown in figure 176.2. 

Samples taken from the injection. system were diluted before being tested, because the concentration· of 

Air bleed 

t 

o--

Vent pipe, 

FEET 

1 ~~Sight glass 

Y and volume 

.80 calibration 

.

60 scale 

.40 

.20 

0 

"----..... .------.J........__ Air-tight dosing 

container 

,..Valve 

Tubing 

Discharge 

pipe 

FIGURE 176.1.-System for injection of concentrated solutio_n. 

activity in the undiluted sample was so great that the 

count rate would have been considerably above the 

capacity of the detection system. A 150-ml (0.32 

pint) sample from the injection was added to 37,000 

ml (9.8 gallons) of background water, and the radioactivity of the diluted sample was counted in the 

counting container. The relationship between the 

count rat!3 in this diluted sample ( Oa) and the count 

rate in the injection system ( 01) is: 

37,150 01= ~ 03=247. 70a. 

The counting period was sufficiently long ( 10,000 

counts) to make the statistical standard error less than 

1 percent. ·Because all samples were counted in the 

same geometry, and because the count rate was well 

within the reliable range of the detection system, the 

count-rate figures could be used rather than an absolute value o! concentration of activity in solving equation 2. 

Flows computed from equation 2 are compared in 

the following table with flows measured volumetrically. 
D186 GEOLOGICAL SURVEY RESEARCH 1 9 6 2 

Comparison of measured and computed flow 

Concentration (counts Measured Dosing per min) Computed Error 

Run Q (cfs) (mlq per Q (cfs) (per- sec) cent) 

C2 Ca 

l ________ 0.0928 12. 64 726 608 0. 0928 0. 0 2 ________ . 0902 12. 95 11, 292 9, 038 . 0907 +. 1 3 ________ . 0895 13. 59 17, 598 12, 914 . 0873 -2.5 4 ________ . 0890 13. 42 5, 756 4, 424 . 0906 +1.8 5 ________ . 0891 13. 26 9,051 7,020 . 0900 +1.0 

TotaL_ . 4496 ------- -------- -------- . 4514 +.1 

The ·comparisons suggest that the accuracy of the 

dilution method is within about 1-percent. With 

some refinements in the equipment, this order of accuracy ·could probably be achieved in measuring the discharge of open channels at field sites provided there 

was no loss of radioactive material between the injection and sampling points. The adsorption problem 

will be considered in other experiments. 

- leads to counter 

~---15" diam---~ 

-Index 

l"X 1" sodium iodide, 

thalli urn-activated 

crystal 

- Counting container 

(volume 37,000 ml) 

FIGURE 176.2.-System for counting radioactivity. 

/ 

QUALITY OF WATER 

177. SOLUTE DEGRADATION IN THE POTOMAC RIVER BASIN 

By H. R. FELTZ and J. vV. w ARK, washington, D.C., and Rockville, ~1d. 

Work done in cooperation with the U.S. Army Engineer lHst1·iot, Baltimore, Md. 

One of the processes by which rock material is 

eroded and transported is the solvent action of water. 

Previous studies show that solute degradation rates 

are related closely to rock type, precipitation, and 

runoff characteristics. This article describes some effects of both lithologic and climatic controls on chemical degradation in the Potomac River basin. 

The dissolved-solids content of several streams in 

the Potomac basin was related to the concurrent water 

discharge. These relationships (fig. 177.1) and flowduration tables (unpublished records of the Geologi~ 

cal Survey) were used to compu'te the average annual 

solute discharges of 11 tributaries in the basin. 

Corrections were made :for the dissolved solids contributed to the basin by precipitation. The average 

solute content of 6 rainfall events in 1961 was 8 parts 

per million. Reported values compare favorably with 

data given by Junge and Werby (1958). Average 

precipitation over individual drainage basins was estimated from U.S. Weather Bureau data, and for ease ~ 

of corr.ection a curve was prepared relating the dissolved solids in tons per square mile to annual precipitation. Dissolved solids carried to earth by precipitation were subtracted from the computed load of dissolved solids in stream flow. Corrections ranged :from 

24 tons per sq mi per yr (square miles per year) :for • 

the upper reaches of the basin to 20 tons per sq mi per 

yr for parts of the Shenandoah Valley. 

Net solute degradation rates range :from 11 to 354 

tons per sq mi per yr (see table). The high solute 

load of the North Branch Poton1ac River reflects pol- _ 

lution from strip mining of coal. Streams such as the, 

North Fork Shenandoah River at Coates Store, Va., -

which drain sandstone and shale of Devonian age,~ 

have low solute loads. Excluding the North Branch 

Potomac River, streams such as Antietam Creek, 
"" 

~ 

ARTICLE 177 D187 

350 

z 

0 300 :J 

~ 

~ • 

0:: 

UJ 

Cl. 250 

en 

..... 

0:: 

< Cl. 

~ 200 

t-=' 

z 

UJ 

..... 

z 

0 

u 150 

en 

c 

:J 

0 

en I 100 c 

UJ 

> 

~ 

0 

~ c 50 

WATER DISCHARGE, IN CUBIC FEET PER SECOND PER SQUARE MILE 

FIGURE 177.1.-Relation of dissolved-solids content to water discharge for streams in the Potomac River basin. (See table for 

stream name and location.) 

Conococheague Creek, and the South Fork Shenandoah River, which drain areas underlain by limestone, 

dolomite, and shale, have the highest solute loads. 

Annual runoff and average dissolved-solids content 

of streams in the upper reaches of the basin are about 

twice those in the lower reaches. Of the streams 

plotted in figure 177.1, Goose Creek, which drains 

primarily· greenstone and granite, exhibits the least 

change in dissolved-solids content for concurrent 

changes in discharge. Solute concentrations of all 

streams is nearly uniform when water discharge exceeds 10 cubic feet per second per square mile. 

Rcrcronco no. (fig. 177.1) 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

REFERENCE 

.lunge, C. E., and Werby, R. T., 1958, The concentration of 

chloride, sodium, potassium, calcium, and sulfate in rain 

water over the United States: Jour. Meteorology, v. 15, 

no. 5, p. 417-425. 

Comp'uted average annual solute degradation rates in the Potomac River basin 

Dissolved Net solute 

Station Drainage area Gross solute Precipitation solids in degradation (sq mi) discharge (tons (inches) precipitation (tons per sq ml) 

per sq mi) (tons per sq mi) 

North Branch Potomac River at Pinto, Md _____________ 596 378 41 24 354 

South Branch Potomac River near Springfield, W. Va ____ 1,471 73 35 20 53 

Conococheague Creek at Fairview, Md ____ :_ ____________ 494 162 39 22 140 

Antietam Creek near Waynesboro, Pa. __________________ 93. 5 198 40 23 175 

South Fork Shenandoah River at Front Royal, Va _______ 1,638 112 38 22 90 

North Fork Shenandoah River at Coates Store, Va ______ 215 33 38 22 11 

North Fork Shenandoah River near Strasburg, Va _______ 772 104 34 20 84 

Potomac River at Point of Rocks, Md __________________ 9,651 132 36 21 111 

Monocacy River at Bridgeport, Md ____________________ 173 97 43 25 72 

Goose Creek near Leesburg, Va _______________________ 338 66 40 23 43 

Potomac River near Washington, D.C _________________ 11, 560 120 37 21 99 

654685 Q-62--18 
D 188 GEOLOGICAL SURVEY RESEARCH 19 6 2 

178. FOAMING CHARACTERISTICS OF SYNTHETIC-DETERGENT SOLUTIONS 

By C. H. WAYMAN, J. B. RoBERTSON, and H. G. PAGE, Denver, Colo. 

Work don e in cooperation with the Federal HotMing Administration 

Synthetic detergents are of three general types: 

(1) Ani~nic, which contains a surfactant (surfacetension lowering agent) in which the oil-soluble portion of the molecule is negatively charged; (2) 

cationic, which contains a surfactant in which the 

oil-soluble . portion of the molecule is positively , 

charged; and ( 3) nonionic, which is not ionized but 

which acquires hydrophilic character from an oxygenated side chain such as polyoxyethylene. Anionic 

alkylbenzenesulfonate (ABS) is the chief surfactant 

·en 

L&J 

1-

:::1 

~ 

200 

180 

160 

140 

.... 

..--

1-

~ 

1- ........- ~ 

...-- ,....--

1-

in commercial detergents. 

Because anionic surfactants in commercial-detergent formulations resist breakdown either after sewage 

treatment or in septic tanks, these compounds are contributing to the pollution of both ground water and 

surface water. One of the effects produced from detergent pollution is foaming. Most persistent foams are 

attributed to soaps, synthetic detergents, and soluble 

- proteins (Moillet and others, 1961, p. 203). In the 

bulk of a solution the concentration of surfactants 

commonly is about 10 ppm (parts per million), but in 

foams such concentrations may exceed 1,000 ppm. Because of the Geological Survey's interest in groundwater pollution, a study was made to determine the 

influence of such factors as detergent concentrations, 

temperature, counter ions, pH, anionic builders, and 

bacteria on foaming characteristics of synthetic-detergent solutions. 

Much of the profuse literature on detergent foams 

suggests that foaming is caused by as little as 0.5 ppm 

of ABS, but our study showed that sodium salts of 

ABS and of nonionic types of detergents will not 

foam stably at concentrations of less than 2 to 3 ppm. 

Foaming at lesser concentrations probably can be attributed to other surfactants, such as organic proteins. Cationic detergents, such as Hyamine 1622, require concentrations of 8 to 10 ppm for foaming. 

Foam stability of numerous commercial anionic, 

nonionic, and cationic detergents is shown in figure 

178.1. Anionic and nonionic types are more stable 

than the one cationic surfactant tested. Foam stability of nonionic surfactants increases as the ratio of 

the hydrophobic to hydrophilic groups of the molecule 

increases. Hyonic PE 70 represents a surfactant containing 70 percent hydrophobic and 30 percent hydrophilic groups. 

~ 

~ 

w' 

~ 120 1-

i= 

>-

< (.) 

L&J 

Q 100 f-

~ 

< 0 

Ll.. 

80 - u.. I() en 00 0:: Q) z 1.0 Ill Ol 0 Q; ..... u.. c E (/') 0 ..... u £ 

_Q u c l1l l1l 0:: z (/') 

60 

40 

ANIONIC 

r--

L&J 0 0 Q) ,..... Ol X 

a.. ~ L&J L&J z Q). a.. a.. E u -~ :s £ ·c: c -~ c 0 0 l1l >. >. Q) 

(/') :I: :I: 1-

NON IONIC 

TYPE OF DETERGENT 

~ 

0 

I() 

L&J 

a.. 

u 

·c: 

0 

>. 

:I: 

t\1 

t\1 

~ 

Q) 

c 

·e 

tO 

>. 

:I: 

n '-.,--1 

CATIONIC 

FIGURE 178.1.-Time required for a column of foam 56 em 

high to decay to 0.3 em for various anionic, nonionic, and 

cationic detergents. 

Tests indicate that the relation between detergent 

concentration and foam stability is nonlinear. For 

pure detergent solutions containing 10, 100, and 1,000 

ppm of ABS at 10°C, the time for a column of foam 

56 em high to decay to 0.3 em is 1, 40, and 280 minutes, respectively. 

Foam stability seems to increase as the temperature 

decreases. At temperatures of 10°C, 20°C, and 30°0, 

the foam height of solutions containing 100 ppm of 

ABS decayed from 56 to 0.3 em in 50, 40, and 20 minutes, respectively. 

Counter ions in solution generally impede the formation of a given attainable foam height. This phenomenon is illustrated in figure -178.2 where the foam-
10 

~ ::J 

s 

9 .~ 

c 

.Q 

c 

0 

c 

8 E 

c. 

c. 

(f) 7 0:: 

w 

tw 

~ 

i= 6 z 

w 

() 

~ 5 

~ 

I 

(!) 

w4 

I 

~ 

~ 

0 

I.J.... 3 

2 

E· 

c. 

c. 

EXPLANATION 

NONIONIC ANIONIC 

I 

COMMERCIAL DETERGENTS 

ARTICLE 178 Dl89 

ing characteristics of several commercially available 

detergents that contain counter ions are compared to 

pure anionic and nonionic surfactants. 

Foaming is influenced markedly by changes in pH. 

As shown in figure 178.3, cationic surfactants are extremely unstable at a pH of more than 7. Anionic 

and nonionic types are stable throughout a large range 

of pH, the anionic type being more stable at higher 

pH and the nonionic being virtually unaffected. 

Anionic builders (detergent components in addition 

to the surfactant) such as phosphate, silicate, and 

carboxymethylcellulose (CMC) ions enhance the tendency of anionic detergent solutions to foam; this 

effect becomes more intense when the solution contains 

bacteria such as Escherichia coli. A mixture of a 

cationic detergent (Hyamine) and anionic builders 

produces virtually no foam (fig. 178.3). 

FIGURE 178.2.-Foam height of various commercial household 

detergents in solution containing 20 mg per l at 20°C. 

Foaming tests on a sample of sewage effluent containing 1,000 ppm of dissolved solids, 6.0 ppm of ABS, 

and 1 X 106 bacteria per ml indicated a poor tendency 

to foam. Because this sample contained the requisite 

amounts of ABS and bacteria to produce foaming 

and because foaming did not occur, the tests indicate 

that some sewage effluents contain natural antifoaming 

agents. As little as 10 to 100 ppm of antifoaming 

agents can prevent foaming of anionic surfactant 

solutions containing as much as 100 ppm of ABS. 

Experiments on solutions containing 100 ppm of Dow 

Corning Antifoam "B" and 100 ppm of ABS gave 

18 

16 

(/) 14 

Ck: 

UJ 

1-

UJ 

::E 12 

~ 

z 

UJ 

(.) 10 

~ 

. ..,.: 8 J: 

~ 

UJ 

J: 6 

::E 

ct 

0 

u.. 4 

2 

0 

2 3 4 5 6 pH 7 8 9 10 11 

FIGURE 178.3.-The influence of pH, bacteria (Escherichia coli), and builders on foam height for various surfactants. 
Dl90 GEOLOGICAL SURVEY RESEAHCH 19 6 2 

no measurable amount of foam. Similar tests on solutions containing 40 ppm of ABS and 10 ppm of the 

cationic Hyamine 1622 failed to create any measurable 

amount of foam. Therefore, small concentrations of 

natural antifoams, such as cationic surfactants, can 

destroy potential foaming in sewage effluents. ·Cationic 

surfactants like Hyamine 1622, which is a germicide, 

might function to destroy bacteria and foams simultaneously. 

This study indicates that water supplies tapping 

ground water aquifers should not foam vigorously at 

ABS concentrations of less than 2.0 ppm, if ABS is 

the only surfactant present. 

The stability of foams in natural water is influenced 

by several variables. Foams are more stable at lower 

temperatures. Foams are unstable at concentrations 

of less than 2.0 ppm of ABS but may foam at lower 

concentrations if other organic surfactants such as 

soaps or proteinaceous material are in solution. The 

types of surfactants most common in natural water 

probably contribute more readily to foaming in the 

pH range from 7 to 10 .. Escherichia coli in surface 

water enhances the tendency to foam. Small concentrations of cationic surfactants or other antifoaming 

compounds can reduce or destroy foaming produced 

from the anionic surfactant ABS. 

REFERENCE 

~oillet, J. L., Collie, B., and Blac~, W., 1961, Surface activity: 

Princeton, D. van Nostrand Co., 518 p. 

179. SURFACE TENSION OF DETERGENT SOLUTIONS 

By C. H. WAYMAN, J. B. RoBERTSON, and H. G. PAGE, Denver, Colo. 

Work done in cooperation with the Federal Housing Administration 

The imp<;rtance of the physicochemical property surface tension in reactions at solid-gas, solid -liquid, or 

solid-liquid-gas interfaces has not been fully realized. 

Surface tension has significance in wettability, which 

indirectly influences adsorption, and in the movement 

of liquids through porous media. A profuse literature 

is available on the surface tension of pure and "built" 

detergent solutions (Fischer and Gans~ 1946; Harris, 

1946; Mankowich, 1953; and others). The surface 

tension of natural water and industrial waste water, · 

·including sewage-plant and septic-tank e~uents, is 

virtually uninvestigated; the only significant study 

in this field is that of Bowers ( 1952) on sewage water 

of Indianapolis. Bowers' study indicated that the 

surface tension of the sewage water ranged from 

38.9 to 71.6 dynes per em; surface tension decreased 

with increase in content of suspended solids; surface 

tension increased with dissolved-oxygen content; and 

detergents are probably the most important surfactants that lower surface tension. 

The effect of concentration of surfactant, pH, temperature, ions present in commercial detergent compounds, and bacteria, on the surface tension of detergent solutions is discussed in this paper. Data 

consist of surface-tension measurements made on laboratory-prepared detergent solutions and sewage effluent from the Denver sewage-treatment plant. 

The surface tension of all solutions was measured 

with a Cassel-type tensiometer, employing the maximum-bubble-pressure technique. In figure 179.1, the 

surface tension of solutions containing various anionic, 

nonionic, and cationic surfactants is plotted as a function of concentration at 20°C. N onionic compounds 

are more surface active than either anionic or cationic 

compounds, which are about equally surface active. 

Santomerse, a low-foaming surfactant, displays the 

lowest degree of surface activity, probably because it 

contains surfactant depressants. 

The influence of temperature on surface tension of 

the anionic detergent alkylbenzenesulfonate (ABS) was 

determined in the. range 20°0 to 35°0 for concentrations 

of as much as 3,000 ppm (parts per million). At 20°0 

the change in surface tension with concentration Co"Y/oc) 

is 0.18 for as much as 110 ppm of ABS; at 35°0 the 

value is 0.36 for as much as 55 ppm of ABS, indicating 

a much steeper surface tension-concentration gradient 
ARTICLE 179 D191 

EXPLANATION 

68 NON IONIC 

cr 

1. Tergitol N Px 

UJ 2. Hyonic PE 70 

~ 64 ANIONIC ~ 

~ 3. Pilot SF 96 

z 5. Santomerse 85 ~ 60 6. N.acconol N RSF 

7. Santomerse E 

(low foaming) 

CATIONIC 

4. Hyamine 1622 

z 

CONCENTRATION, IN PARTS PER MILLION 

FIGURE 179.1.-Variation of surface tension with concentration for various surfactants at 20 °C. 

at higher temperatures. The Gibbs adsorption equation for surface excess (r, in moles per cm2

) is: 

where 

r= _c_ 0')' 

RToc 

c=concentration in moles per liter 

R =gas constant 

T=absolute temperature 

(1) 

and o-yjoc=slope of surface tension-concentration 

curve. 

Calculations based on equation 1 indicate that o-yfoc 

changes only slightly for as much as 140 ppm of ABS 

in the temperature range 20°0 to 35°0. Hence, 

temperature has a greater influence on surface tension 

than concentration for the range of conditions indicated. 

Because most commercial detergents contain other 

compounds as well as ABS, the surface tension was 

determined for solutions of 17 different commercial 

detergent products. Enough of each product was 

used to give 100 ppm of ABS in solution. At this 

concentration of ABS and at 20°0, the surface tension of the 17 detergent solutions ranged from 50 to 

63 dynes per em. These data indicate that, in detergents, compounds other than ABS increase surface 

tension. Solutions of commercial products containing 

10 ppm of ABS plus 100 million bacteria per ml at 

20°0 gave surface tensions ranging from 70.5 to 72.0 

dynes per em as compared to about 68 without bacteria; apparently, bacteria reduce the surface activity 

of surfactants in solution. 

The influence of pH on surface tension is shown 

in figure 179.2. In dilute solutions of anionic surfactants, surface tension increases with increase in 

pH, whereas in solutions of cationic and nonionic 

surfactants, surface tension decreases with increase 

in pH. Phosphate, silicate, and carboxymethylcellulose, along with ABS, tend to inhibit the influence of 
D192 GEOLOGICAL SURVEY RESEARCH 19 6 2 

2. 10 ppm Hyamine (cationic) 

3. 10 ppm ABS (anionic) 

4. 10 ppm Tergitol (nonionic) 

5 7 8 9 10 

pH 

FIGURE 179.2.-Variation of surface tension of surfactant 

solutions with pH, at 20°C. 

pH on the surface tension of a surfactant solution. 

Mankowich ( 1953) has indicated that pH and other 

iol).s have little influence on surface tension in highly 

concentrated surfactant solutions (1,000 to 4,000 ppm) ; 

evidently, tl~e pH effect is masked at higher concentrations by surfactant saturation at the· air-solution 

interface. 

Surface-tension measurements of the sewage effiuent 

from the Denver sewage-treatment plant were made 

for a 2-month period. The surface tension of the 

effluent ranged from 63 to 71.5 dynes per em at 20°C; 

the surface tension of pure water at 20°C is 72.75 

dynes per em. Weekly determinations of certain constituents in this water had the following ranges: 

detergent ( ABS), 5.5 to 6.5 ppm; dissolved solids, · 

750 to _1,120 ppm; bacteria (Escherichia coli), 150,000 

to 250,000 per ml; and dissolved oxygen, 0.0 to 3.5 

ppm. For a sewage effluent at Indianapolis, Bowers 

found that the surface tension ranged from :1:5 to 60 

dynes per em at 25°C. Although a minor amount of 

the difference between the surface tension of sewage 

effluents at Denver and Indianapolis can be attributed 

to a difference in temperature of measurement (20°C 

at Denver and 25°C at Indianapolis), most of the 

difference probably is due to variation in composition 

of the sewage effluent at the two cities. The composition of a sewage effluent is influenced by waste disposal from industry, agriculture, and other sources. 

Because no two cities are likely to have sewage effluents 

of identical compositions, differences in surface tensions of their sewage effiuents are to be expected. 

In areas of sewage spreading or storage of natural 

water containing surfactants, knowledge of the surface 

tension of these liquids is important because the rate 

at which water wets and infiltrates soils depends in 

part on the surface tension of the liquid phase. As of 

March 1962, the detergent ( ABS) concentration of 

m~st surface-water supplies is less than 10 ppm; at 

this concentration, the surface tension of water containing ABS surfactant is only slightly less than that 

of pure water. 

This study shows that th~ concentration of ABS 

found in natural water cannot lower surface tension 

apprecia-bly below that of pure water. At temperatures 

of more than 20°C, the surface tension-concentration 

gradient increases considera-bly for dilute surfactant 

solutions. In solutions containing less than 10 ppm 

of ABS, ions other than surfactants tend to increase 

surfa-ce tension above that of the pure surfactant alone· 

bacteria make the effect more pronounced. The re: 

suits .of this study will be applied to investigations 

of the influence of surface tension on wettability of 

soils and aquifer materials. The evaluation of surface tension in flow. theory has received no significant 

consideration to date. 

REFERENCES 

Bowers, D. R., 1952, Measurement of surface tension of sewage II. Indianapolis studies: Sewage and Indus. Wastes, 

v. 24, p. 1447-1455. ·. 

Fischer, E. K., and Gans, D. M., 1946, Surface-active agents 

at interfaces: New York Acad. Sci., v. 46, p. 371-406. 

Harris, J. C., 1946, Builders with synthetic detergents: Oil 

and Soap, v. 23, p. 101-110. 

Mankowich, A. M., 1953, Physiochemical properties of surfactants: Indus. and Eng. Chern., v. 45, p. 2759-2766. 
SUBJECT INDEX 

[For major topic headings such as "Economic Geology," "Stratigraphy," "Ground Water," see under State names or refer to table or contents] 

A Article· 

ABS, effect on roaming of water.............. 178 

Agassiz, glacial Lake, stratigraphy........... 170 

Alaska, stratigraphy, McCarthy C-5 quadrangle............................ 133 

Alteration, hydrothermal, hot springs........ 153 

relation to occurrence or uranium________ 122 

Alunite, in hot-spring alteration._____________ 153 

Wyoming, Aspen Mountain______________ 123 

Ansonia Gneiss, Connecticut, definition._____ 128 

Aqu!Ccrs, compaction.________________________ 172 

glacial dr!Ct •••• ----------------------~---- 157 

glaciofluvial and shore deposits.__________ 170 

sandstone.------------------------------- 171 

Arizona, economic geology, southeastern._____ 120 

geophysics, Meteor Crater________________ 1~9 

paleontology, northeastern________________ 161, 

sedimentation, 'Colorado Plateau.-------- 163 

structural geology, Navajo County_______ 143 

Arkansas, stratigraphy, Washington County_ 130, 131 

Atoka Formation, Arkansas, type section..... .130 

Avalanches, erosional features .•. _____________ 155 

B 

Bloyd Formation, Brentwood Limestone 

Member, Arkansas, type section. 130 

Dye Shale Member, Arkansas, .type 

section.-------------------------- 131 

Kessler Limestone Member, Arkansas, 

typo section______________________ 130 

Trace Creek Slmle Member, Arkansas, 

type section.--------------------- 131 

Woolsey. Member, Arkansas, type section. 130 

Donanza King Formation, Nevada, definition. 127 

Buttress Diabase, Connecticut, definition.... 128 

c 

CallCornla, geomorphology, Kings River area~ 155 

geophysics, San Bernadino County_______ 150 

ground water, Santa Clara Valley________ 17.2 

Igneous petrology, Inyo Mountains_______ 145 

structural geology, Inyo Mou'ntains______ 145 

Owens Valley __ ---------------------- 145 

San Joaquin Valley___________________ 146 

Sierra Nevada._______________________ 145 

Cambrian, Nevada, paleontology and stratigraphy_.-----------------------... 127 

Nevada, stratigraphy_____________________ 126 

Camplto Formation, Montenegro Member, 

Nevada, stratigraphic relations... 126 

Canyon Creek fault, Arizona, description..... 143 

Carbon-14 age determinations, Pliestoccne strata ..•••••• __ . ____ ••. __ .. __ -.-.- 160 

Carboniferous. See Mississippian, Pennsylvanian. 

Carrara Formation, Nevada, definition....... 127 

Cedar Ridge Till, Wyoming, definition....... 159 

Chlle, structural geology, San Pedro de 

Atacama._·············---------- 147 

Olausthallte, thermal expansion.............. 152 

Olay minerals, ln hot springs................. 153 

Clays, relation to uranium deposits........... 124 

Coeslte, thermal expansion •• ----------------- 152 

Artiele 

Colorado, economic geology, Teller County... 121 

Igneous petrology, central Front Range.. 154 

mineralogy, Teller. County •. ------------- 121 

paleontology and stratigraphy, Glenwood 

Canyon.......................... 129 

sedimentation, Colorado Plateau......... 163 

Colorado, stratigraphy, Minturn quadrangle. 132 

Connecticut, stratigraphy, south-centraL____ 128 

Convolute bedding, definition................ 164 

Copper porphyries, K-Ar and Rb-Sr age 

determinations................... 120 

Cretaceous, western Interior, paleontology~... 161 

Wyoming, strand lines................... 134 

Crustal deformation, Idaho, Snake River 

Plain............................. 141 

Cryptovolcanoes, Serpent Mound, Ohio...... 148 

Cytherelloidea, possible indicator of paleotemperatures.------------------------ 162 

D 

Deep Spring Formation, Nevada, stratigraphic 

relations. ________________ --------- 126 

Degradation, solute, rates.------------------- 177 

Delaware, surface water, Potomac River 

basin.---------------------------- 173 

Derby Hill Schist, Connecticut, definition.... 128 

Deamoacaphitea, Range Zone__________________ 161 

Detergents, foaming characteristics___________ 178 

surface tension of solutions________________ 179 

Devonian, Connecticut, regional metamorphism. ____ -----------------~----- 128 

Din woody Lake Till, Wyoming, definition.__ 159 

Discharge, stream, measurement with radioisotopes.------------------------- 176 

Dunderberg Shale, Nevada, definition________ 127 

E 

Eagle Valley Evaporite, Colorado, correlation. 132 

Edge Isolation, description of technique....... 166 

Electrical resistivity, magnetite deposits .• ____ 150 

Emigrant Formatiol), Nevada, stratigraphic 

relations .• ------------------------ 126 

Eocene, Florida, stratigraphY----------~------ 136 

F 

Faults and faulting, Arrowhead fault, Nevada. 144 

Faults and faulting, geobydrologic evidence.. 142 

Inyo Mountains, Calif..__________________ 145 

Owens Valley, Calif._____________________ 145 

Jackson, Wyo .• -------------------------- 160 

Navajo County, Ariz_____________________ 143 

Sierra Nevada, Calif...___________________ 145 

Tooele Valley, Utah______________________ 142 

Feldspars, in bot-spring alteration____________ 153 

Flood-frequency curves, In adjusting flowduration curves___________________ 1~4 

Florida, stratigraphy and structure, Escambia 

County--------------------------- 136 

stratigraphy and structure, Santa Rosa 

County--------------------------- 136 

Note.-Numbers refer to articles. 

Article 

Flow-duration curves, defining relations between._.------------------------- 174 

Foam stability, factors affecting______________ 178 

Folds and folding, laboratory studies ______ 164, 165 

Forsterite, thermal expansion_________________ 152 

G 

Galena, thermal expansion------------------- 152 

Georgia, ground water, Jonesboro_____________ 169 

Glacial drift, aquifers.----------------------- 157 

Glaciofluvial deposits, as aquifers_____________ 170 

Gradiometer, declination, nse in field determination of polarity_------------- 151 

Granitic rocks, correlation____________________ 145 

Gravity studies, Idaho, Sn~e River Plain... 141. 

Basin and Range province ••• _____________ 140 

H 

Hale Formation, Cane Hill Member, Arkansas, type sectloD-------------~---- 130 

Prairie Grove Member, Arkansas, type 

section. ___ ----------------------- 130 

Harkless Formation, Nevada, stratigraphic 

rel!itions. ------------------------- 126 

Hot springs, hydrothermal alteration_________ 153 

Hydraulics, model of control structure._______ 175 

Idaho, geophysics, Gem V~lley.______________ 140 

geophysics, Snake River Plain____________ 141 

structural geology, Gem Valley___________ 140 

Snake River Plain____________________ 141 

Impact craters, Serpent Mound, Ohio.~------ 148 

Indiana, glacial geology, Lake County._______ 157 

Indonesia, engineering geology, West Java.... 125 

Interior drainage, structural controL_ •. ------ 146 

Intraformational recumbent folds, laboratory 

studies •.• ---------------------- 164, 165 

Intraformational thrust structures, definition.. 164 

Irregularly contorted beds, definition_________ 164 

J 

Joints and jointing, relation to permeability__ 169 

Juana DiAz Formation, Puerto Rico, ground 

water----------------------------- 137 

Jurassic, Alaska, McCarthy C-5 quadrangle. 133 

Colorado Plateau, wind direction_________ 163 

K 

Kentucky, surface water, Eastern Coal Field. 174 

Klondike Mountain Formation, Washington, 

definition ______________ ------_____ 135 

L 

Lake Agassiz, Vermilion end moraine________ 158 

Land subsidence, relation· to compaction of 

aquifers. __ .---------------------- 172 

Tulare Lake bed, California______________ 146 

Leadville Limestone, Colorado, age___________ 129 

Dl93 
D194 

M Article 

Magnetic surveys, basalt flows. __ --~--------- 140 

Magnetic susceptibility, magnetite deposits._ 150 

Magnetite deposits, electric and magnetic 

properties. __ -----------~--------- 150 

Maps, edge isolation__________________________ 166 

shaded relief, method of preparation______ 167 

Maroon Formation, Colorado, correlation____ 132 

Maroon Formation, Jacque Mountain Limestone Member, :Colorado ______ ·~--- 132 

Maryland, quality of water, Potomac River.. 177 

surface water, Potomac River basin______ 173 

Massachusetts, geophysics, Merrimack River 

valley __ -------------------------- 156 

glacial geology, Merrimack River valley__ 156 

ground water, Merrimack River valley__ 156 

Mesaverde Formation, Wyoming, cprrel~tiori 

· and facies------------------------- 134 

Metamorphic rocks, relation of jointing to 

permeability_-------------------- 169 

Minnesota, glacial geology; Nett Lake Indian 

Reservation._-------------------- 158 

glacial geology, Stephen._---------------- 170 

ground water, Stephen. __ ------~--------- 170 

Minturn Formation, Colorado, correlation... 132 

Miocene, Florida, stratigraphy __ ---~--------- 136 

Missisippian, Arkansas, stratigraphy_________ 130 

Colorado, paleontology and stratigraphy_ . 129 

Montana, paleontology, we:tern.~------------ 161 

Morrison Formation, New Mexico, clay content.----------------------------- 124 

Morrow Series. See Bloyd Formation, Hale 

Formation. 

Mule Spring Limestone, Nevada, stratigraphic relations__________________ 126 

N 

Nacimiento Formation, New Mexico, aquifers.. 171 

Nevada, geochemistry, Steamboat Springs.. 153 

stratigraphy, Esmeralda County_________ 126 

Nevada Test Site_____________________ 127 

structural geology, Muddy Mountains... 144 

New Jersey, ground water, Wharton Tract.. 168 

New Mexico, economic geology, Ambrosia 

Lake area.----------------------- 124 

ground water, San Juan Basin___________ 171 

mineralogy, Ambrosia Lake area_________ 124 

paleontology, western.------------------- 161 

sedimentation, Colorado Plateau.-------- 163 

surface water, Rio Grande________________ 175 

0 

O'Brien Creek Formation, Wa~hington, definition._-------------------------- 135 

Ohio, economic geology, southern____________ 148 

structural geology, southern.------~------. 148 

Ojo .Alamo Sandstone, New Mexico, aquifers.. 171 

Oligocene, Florida, stratigraphy______________ 136 

Puerto Rico, stratigraphy________________ 137 

Ostracodes, Cretaceous. ____________________ ·__ 162 

p 

Paleomagnetism, field determination---~----~ · i51 

P.aleotemperatures; indicators________________ i62 

GEOLOGICAL SURVEY RESEARCH 19 6 2 

Article 

Pennsylvania, surface water, Potomac River 

basin _____ -----------------------_ 173 

Pennsylvanian, Arkansas, stratigraphy _____ 130,131 

Pennsylvanian, Colorado, stratigraphy------- 132 

Colorado Plateau, wind direction_________ 163 

Permeabil1ty, relation to jointing in rocks.___ 169 

Permian, Colorado, stratigraphy_____________ 132 

Permian, Colorado Plateau, wind direction___ 163 

Pine Mountain overthrust, Virginia__________ 139 

Pitkin Limestone, Arkansas, type section____ 130 

Pleistocene, Florida, marine terraces.--------~ 136 

Indiana, glacial drift______________________ 157 

Wyoming, glacial tills____________________ 159 

stratigraphy-------------------------- 160 

Pliocene, Florida, stratigraphy __ ------------- 136 

Poleta Formation, Nevada, stratigraphic relations. ---------------------------- 126 

Potassium-argon age determinations, copper 

porphyries________________________ 120 

Precambrian, Colorado, igneous petrology____ 154 

Precambrian, Nevada, stratigraphy__________ 126 

Prospect Gneiss, Connecticut, definition______ 128 

Prospecting, uranium________________________ 122 

Puerto Rico, ground water, Yanco area_______ 137 

stratigraphy, Yanco area_________________ 137 

Q 

Quaternary. See Pleistocene, Recent. 

R 

Radioisotopes, in measuring stream discharge_ 176 

Recent, Washington, pyroclastic deposits_____ 138 

Reed Dolomite, Nevada, stratigraphic relations.---------------------------- 126 

Remanent magnetism, field measurement.... 151 

Rubidium-strontium age determinations, copper porphyries-----~-------------- 120 

Runoff, estimation from short records________ 173 

s 

Sacagawea Ridge Till, Wyoming, definition._ . 159 

Salt domes, formation of----~----------------- 147 

San Jose Formation, New Mexico, aquifers... 171 

Sandstone, eolian, Colorado Plateau__________ 163 

ground water in__________________________ 171 

Sanpoil Volcanics, Washington, definition.... 135 

Scatter Creek Rhyodacite, Washington, 

definition _____________ ~----------- 135 

Sedimentation, structure for measuring rate.. 175 

Sediments, studies of folds and folding ______ 164, 165 

Seismic investigations, depth of fill in river 

valleys ___ ------------------------ 156 

Shore deposits, as aquifers____________________ 170 

Southington Mountain Schist, Connecticllt, definltlon______ ___ _ __ __ _ __ ___ _ __ __ 128 

Snow chutes, formation. __ -------------------

Sphalerite, thermal expansion.---------------

See also Zinc. ' 

Stilleite, thermal expansion ..• ·----------------

Straits Schists, Connecticut, definition. __ ----

Streamflow, estimation from short records •••• measurement with radioisotopes _________ _ 

structure for measuring __________________ _ 

·Strontianite, thermal expansion ••. .: .... ~----­

Surfactant solutions, surface tension~---------

Note.-Numbers refer to articles. 

155 

152 

152 

128 

173 

176 

175 

152 

179 

Article 

Surfactants, effect on foaming of detergents... 178 

Surface tension, detergent solutions___________ 179 

T 

Temperature, ground water_----------------- 168 

Tertiary, Chile, salt domes___________________ 147 

Washington, stratigraphy________________ 135 

Wyoming, stratigraphy __ ---·------------ 123 

See also Eocene, Oligocene, Miocene, 

Pliocene. 

Thalenite, occurrence in Colorado____________ 121 

Thermal expansion, minerals_________________ 152 

Thermoluminescence of rocks, as an indicator 

of shock._------------------------ 149 

Triassic, Colorado Plateau, wind direction.-- 163 

u 

Uranium, alteration related to________________ 122 

relation of deposits to clays_______________ 124 

Utah, ground water, Tooele Valley___________ 142 

paleontology,· eastern.-------------------- 161 

sedimentation, Colorado Plateau_________ 163 

structural geology, Tooele Valley--------- 142 

v 

Virginia, quality of water, Potomac River.... 177 

structural geology, Powell River valley___ 139 

surface water, Potomac River basin______ 173 

Volcanic ash, carbon-14 ages__________________ 138 

Volcanism, Idaho, Snake River Plain_________ 141 

w 

Washington, stratigraphy, Ferry County_____ 135 

stratigraphy, Mount Rainier_------------ 138 

Mount St. Helens·-------------------~------- 138 

Washington, D.C., quality of water, Potomac 

River----------------------------- 177 

Wepawong Schist, Connecticut, definition____ 128 

West Rock Diabase, Connecticut, definition.. 128 

West Virginia, quality of water, Potomac 

River._-------------------------- 177 

surface water, Potomac River basin______ 173 

Wisconsin age, Minnesota, glacial geology____ 158 

Woodbridge Granite, Connecticut, definition. 128 

Woodtick Gneiss, Connecticut, definition_____ 128 

Wurtzite, thermal expansion__________________ 152 

Wyman Formation, Nevada, stratigraphic 

relations__________________________ 126 

Wyoming, economic geology, Aspen Mountain.-- _______________ ;___________ 123 

economic geology, Shirley Basin__________ 122 

glacial geology, Jackson___________________ 160 

Wind River Mountains______________________ 159 

paleontology western·------------~------- 161 

paleontology and stratigraphy, southern.. 134 

y 

Yttrium silicate, thalenite____________________ 121 

z 

Zinc, in explosion structures__________________ 14 

, .. 

~' 
Article 

Adams, J. W --------------------------------- 121 

Albers, J. P __ -------------------------------- 126 

Arms tong, F. C._---------------------------- 140 

Ash, S. R.- __ -------------------------------- 171 

Baker, C. H., Jr --------------------------- 164, 165 

Baltz, E. H.--------------------------------- 171 Barnes, Harley_______________________________ 127 

Blackmon, P. D------------------------------ 123 

.Brock, M. R. _ ------------------------------- 148 

Byers, F. M., Jr------------------------------ 127 

Carter, R. W --------------------------------- 176 

Christiansen, R. L. __ ------------------------ 127 

Clarke, A. B._------------------------------- 166 

Cobban, W. A----------------------------- 134, 161 

Cox, Allan·----------------------------------- 151 

Crandell, D. R-------------------~----------- 138 

Creasey, S. C--------------------------------- 120 

Davis, G. H------------------------------- 146, 155 

Dingman, R. J ------------------------------- 147 

Doell, R. R .•• ------------------------------- 151 

Elsenlohr, W. 8., Jr ___ ----------------------- 173 

Feltz, H. R----------------------------------- 177 

Finnell, T. L--------------------------------- 143 Frederick, B.]. ______ :_______________________ 176 

Fritts, C. E._-------------------------------- 128 

Gates, J. 8------------------------------------ 142 

Granger, H. C .• ·----------------------------- 124 

Green, J. H. ___ --------------------------- 146, 172 

Grossman, I. G----------:..-------------------- 137 

AUTHOR INDEX 

Article 

Hallgarth, W. E ______________ :_______________ 129 

Harris, D. D--------------------------------- 175 

'Harshman, E. N _ ---------------------------- 122 

Havens, R. G __ ------------------------------ 121 

Henbest, L. G----------------------------- 130, 131 

Heyl, A. 0---·-------------------------------- 148 

Hildebrand, F. A----------------------------- 121 

Johnson, G. R-------------------------------- 149 

Kirkpatrick; G. A---------------------------- 174 

Kistler, R. W --------------------------------- 120 

LaFehr, T. R-------------------------------- 141 

Lang, S. M----------------------------------- 168 

Longwell, C. R------------------------------- 144 

Love, J. D-------------------------------- 123, 160 

Lovering, T. S. ___ ------~-------------------- 132 

Mabey, D. R--------------------------------- 140 

McCabe, j. A._------------------------------ 174 

McGrath, J. G __ ----------------------------- 149 

McKee, D. M----------------------------- 164, 165 MacKevett, E. M., Jr________________________ 133 

Maclay, R. W -------------------------~------ 170 

Mallory, W. W ------------------------------- 132 

Marsh, 0. T --------------------------------- 136 

Miller, R. D--------------------------------- 138 

Miller, R. L--------------------------.. ·------ 139 

Muessig, Siegfried·--------------------------- 135 

Mullineaux, D .. R-------------- -------------- 138 

Norvltch, R. F------------------------------- 158 

Page, H. G-------------------------------- 178, 179 

Note.-Numbers refer to articles. 

Article 

Pakiser, L. C--------------------------------- 141 

Poole, F. G. ___ ------------------------------ 163 

Reck, C. W-------------·-------------------- 176 

Reynolds, M. A--------------------------- 164, 165 

Richardson, E. V.---------------------------- 175 

Richmond, G. M----------------------------- 159 

Rhodehamel, E. C--------------------------- 168 

Roach, C. H--------------------------------- 149 

Robertson, J. B--·------------------------ 178, 179 

Rosenshein, J. 8--·--------------------------- 157 

Ross, D. C----------------------------------- 145 

Rubln, Meyer-------------------------------- 138 

Sammel, E. A-------------------------------- 156 

Scbiner, G. R. ---·--------------------------- 170 

Sigvaldason, G. E---------------------------- 153 

Sims, P. K----------------------------------- 154 

Skinner, B. 1--------------------------------- 152 

Skipp, B. A. L----------------------·-------- 129 

Sohn, I. G------------------------------------ 162 

Stacy, J. R----------------------------------- 167 

Sterrett, T. S------------------------------·-- 149 

Stewart, J. H-------------------------~------- 126 

Stewart, J. W -------------------------------- 169 

Taylor, D. W _ ---.---------------------------- 160 

Taylor, R; B-------------------.-------------- 154 

Waldron, H. A------------------------------- 125 

Wark, J. W -"-------------------------------- 177 

Wayman, C. H---------------------------- 178, 179 

West, S. W----------------------------------- 171 

White, D. E----•--------------·-----·-------- 153 

Zablocki, C. J -------------------------------- 150 

Zapp, A. D.-------------------------------- 134 

D195 

U.S. GOVERNMENT PRINTING OFFICE. 1962 o--654685