Copper and Uranium

Deposits of the Coyote

District, Mora County

New Mexico

GEOLOGICAL SURVEY BULLETIN 1030-L

This report concerns work done on behalf 

of the U. S. Atomic Energy Commission 

and is published with the permission of 

the Commission

Copper and Uranium 

Deposits of the Coyote 

District, Mora County 

New Mexico

By C. M. TSCHANZ, D. C. LAUB, and G. W. FULLER

CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

GEOLOGICAL SURVEY BULLETIN 1030-L

This report concerns work done on behalf 

of the U. S. Atomic Energy Commission 

and is published with the permission of 

the Commission

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1958
.- , UNITED STATES DEPARTMENT OF THE INTERIOR 

FRED A. SEATON, Secretary

GEOLOGICAL SURVEY 

Thomas B. Nolan, Director

"«?" >.* ''

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

Washington 25, D. G.
CONTENTS

Page

Abstract__ ______________________________________________________ 343

Introduction. _____________________________________________________ 344

Location and accessibility_____________________-_______----_-_-- 344

Topography __________________________________________________ 344

Previous work-________________________________________________ 345

Purpose and methods__--________________-______-__-_----_----- 345

Acknowledgments. ____________________________________________ 346

Geology______________________________________________________ 346

Geologic history.._____________________________________________ 346

Stratigraphy._________________________________________________ 347

Precambrian rocks____--________-__________-__-____-------- 347

Magdalena group________________________________________ 349

Description.._________________________________________ 349

Fossils.-._______________________________ 349

Sangre de Cristo formation_________________________._______ 350

Description...________________________________________ 350

Fossils._______ _______________________________________ 354

Conditions of deposition________________________________ 354

Yeso formation__________________________________________ 355

San Andres formation (Glorieta sandstone member)__________ 355

Bernal formation_________________________________________ 355

Santa Rosa sandstone_-______-_________________-____--_--_- 355

Quaternary(?) basalt-_-_______________-__-_______-_---_--_- 355

Structure..___________________________________________________ 356

Mineral deposits_____________________________________________ 356

Copper deposits___________________________________--____-- 357

Description.__________________________________________ 357

Mineralogy ___________________________________________ 369

Uranium deposits_____-__-____-________--___-____-------_ 370

Uranium deposits in sandstone,_________________________ 370

Area B, Bias Medina property_________-_________-__ 370

Area F, Arturo Le Deux property.__________________ 378

Uraniferous siltstone and shale__________________________ 3791

Mineralogy of uranium deposits_____-_______-___--_____- 379

Chemical characteristics of uranium-bearing sandstone. _____ 380

Geochemical prospecting.________________!_________________ 382

Origin..__________________________________ 383

Copper deposits-_---______________-_________-__-______ 383

Uranium deposits____________________________________ 385

Uraniferous siltstone_______________________________ 386

Uranium-vanadium deposits in sandstone_____________ 388

Summary. ____________________________________________ 391

Comparison with other copper-uranium deposits..-.---________ 391

Guides to ore deposits____________________________________________ 392

Conclusions._ _____________________________________________________ 393

Literature cited___________________________________________________ 394

Index._________________________________________________________ 397

m
IV CONTENTS

ILLUSTRATIONS

[Plates 24-32 in pocket]

PLATE 24. Generalized geologic map.

25. Geologic map of area A.

26. Geologic map of area B.

27. Geologic map of area C.

28. Geologic map of area E.

29. Geologic map of area F.

30. Geologic map of area G.

31. Geologic map of area H.

32. Geologic map of area 7.

33. Photomicrographs of copper ores __________________ Facing 378

34. Photomicrographs of uraniferous sandstone.________ Facing 379

FIGURE 67. Index map of Mora County, N. Mex_________________ 344

68. Columnar section of sedimentary rocks.________________ _ 348

69. Columnar section of Sangre de Cristo formation..... ____ 351

70. Columnar section of main ore-bearing interval-____________ 352

71. Section showing relationship of copper to rock types, area H__ 367

72. Section showing concentration of copper and uranium in carbonaceous shale, area H_-_________-_____--_------_--__ 368

73. Section along ore sandstone, Bias Medina property _________ 370

TABLES

1. Description of the Sangre de Cristo formation ______________ 353

2. Marine fossils of the Sangre de Cristo formation ____________ 354

3. Analytical data for samples from area A (pi. 25)____________ 357

4. Analytical data for samples from area B (pi. 26)____________ 359

5. Analytical data for samples from area C (pi. 27)____________ 360

6. Analytical data for samples from area E (pi. 28)____________ 361

7. Analytical data for samples from area F (pi. 29)____________ 362

8. Analytical data for samples from areas G and H (pis. 30 and

31)_-__--_._---..--_-_--_-----_--_--_--_-----__ 364

9. Analytical data for samples from area J (pi. 32)__-_--__----_ 365

10. Analytical data for samples outside areas of large-scale maps. _ 366

11. Spectrographic, chemical, and radioactivity analyses of

selected copper and uranium samples.___________________ 372

12. Chemical characteristics of uranium-bearing sandstone_ ____- 381
CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

COPPER AND URANIUM DEPOSITS OF THE 

COYOTE DISTRICT, MORA COUNTY, NEW MEXICO

By C. M. TSCHANZ, D. C. LAUB, and G. W. FULUSR

ABSTRACT

The copper and uranium-vanadium deposits of the Coyote district, Mora 

County, N. Hex., are confined to the lower 2,000 feet of the Sangre de Cristo 

formation of Pennsylvanian and Permian (?) age. A narrow belt of deposits 

in steeply dipping or overturned rocks extends for 7 miles along Coyote Creek 

south of Guadalupita.

Earlier studies showed that the copper deposits contained uranium, but the 

reserves and the uranium content of the copper-bearing shale are too small 

to justify any attempt to recover uranium. Several small, commercial-grade 

uranium deposits have been discovered in sandstone, however.

Small isolated lenses of copper-bearing carbonaceous shale, siltstone, limestone or sandstone, interbedded with predominantly red rocks, are present at 

12 or more stratigraphic levels. The better deposits, in carbonaceous shale, 

average about 2 percent copper. The copper content of the other rocks is usually 

lower, but small concentrations may contain 6 percent copper. The principal 

copper minerals are chalcocite and malachite. Chalcocite replaces wood and 

forms nodules that contain small, variable amounts of pyrite, bornite, covellite, 

and, rarely, uraninite.

The uranium deposits occur as small, closely spaced pockets that are commonly localized by sedimentary structures within one or more fluviatile arkosic 

sandstone beds near the middle of the formation, particularly where carbonized 

wood and clay and rock fragments are abundant. The uraniferous sandstone 

is commonly stained pink by hematite that was probably introduced with the 

uranium. The color increases in intensity with the radioactivity.

The outcrops of the uranium deposits are typically inconspicuous, but close 

inspection reveals malachite, chalcopyrite, black vanadium minerals of micaceous 

habit, metatyuyamunite, and microscopic grains of an unidentified black uraniferous substance. The proportion of copper, uranium, and vanadium is 

variable and any of these metals may be dominant in the ore.

The metals probably were derived from Precambrian granitic rocks. Copper 

and minor amounts of uranium were deposited in local stagnant basins by 

reaction with hydrogen sulfide and decaying organic material. The uraniferous 

shale and the copper deposits are probably syngenetic, or nearly so, but the 

uranium deposits in sandstone are epigenetic and probably were deposited from 

ground waters with a possible hydrothermal admixture. The uranium and 

vanadium may have been reconcentrated from earlier, low-grade, syngenetic 

deposits.

The average copper ore body assays about 1.5 percent copper and contains less 

than 1,000 tons. The small size of known, commercial-grade uranium pockets

343
344 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

and the small total uranium reserves will permit small-scale mining only under 

favorable conditions. Further exploration probably would result in an increase 

of uranium reserves, but no large deposits are expected.

INTRODUCTION

LOCATION AND ACCESSIBILITY

The Coyote district is in Mora County in the north-central part of 

New Mexico (fig. 67). The district can be reached from Las Vegas,

MORA

I COUNTX ,

I Santa Fe. <2~P* [

I . Las Vegas 

(Albuquerque |

I NEW I 

(MEXICO I

INDEX MAP

^Las Vegas

FIGUBB 67. Index map of Mora County, N. Mex.

N. Mex., by traveling 28 miles north on State Route 3 to Mora, 8 miles 

north on State Route 38, and 2 miles east on an unimproved road. 

The district can also be reached by turning off State Route 3 at 

La Cueva and following State Route 21 for 6 miles, 2 miles west to 

Lucero on an unimproved road and 3 miles north along Coyote Creek. 

The roads in the district are ungraded and in poor condition. The 

nearest railroad shipping points are Watrous and Las Vegas. The 

nearest uranium mill and buying station is at Ship Rock, N. Mex. 

Sufficient water is probably available in Coyote Creek to operate a 

small mill.

TOPOGRAPHY

The narrow north-south valley of Coyote Creek approximates the 

boundary between the gently dipping Permian and Mesozoic rocks 

of the High Plains to the east and the Pennsylvanian and Precambrian
COPPER AND URANIUM DEPOSITS, COYOTE DISTRICT, N. MEX. 345

rocks of the Southern Kocky Mountains to the west. The district is 

on the east flank of a north-south hogback between Coyote Creek 

on the east and Turquillo Valley on the west.

PREVIOUS WORK

The copper deposits of the district have been known for 50 years. 

Brief descriptions of the district have been published by Lindgren, 

Graton, and Gordon (1910, p. 109); Lasky and Wooton (1933, p. 84); 

Harley (1940, p. 42-43). In 1944 Kead, Sample, and Shelton (written 

communication, 1954) examined the deposits and described them. 

Bachman and Kead (written communication, 1952) discovered radioactive material in the district in 1951. Gott and Erickson (1952) 

visited the district and showed that the radioactivity was caused by 

uranium. As a result, the Geological Survey began an intensive 

study of the district for the Atomic Energy Commission, first by 

Zeller and Baltz (1954) and later by the writers of this report.

The district is shown on a geologic map of the Ocate area by Bachman (1953). A generalized topographic and geologic map of most of 

the district on a scale of 1:12,000 is included in a report by Zeller and 

Baltz (1954, fig. 4).

PURPOSE AND METHODS

Preliminary work in the Coyote district in 1952 showed that widespread copper-bearing carbonaceous shale contained small amounts of 

uranium, indicating the possibility of very large reserves of low-grade 

copper ores from which uranium might be recovered as a byproduct. 

The present study was begun primarily to explore this possibility. A 

secondary objective was the gathering of data on the origin of the ore 

deposits and the relationship between the copper and uranium deposits. As work progressed, the uranium content of the copper-bearing shale was found to be negligible and the plan was revised to include evaluation of newly discovered uranium-vanadium deposits in 

sandstone.

The most promising areas were mapped on a scale of 1 inch to 200 

feet. Two small areas were mapped on a scale of 1 inch to 50 feet. The 

total area mapped was about 1.5 square miles. The most promising 

deposits were explored by about 200 shallow hand-dug trenches and 

25 shallow jeep-mounted-auger holes. The trenches were sampled and 

mapped on a scale of 1 inch to 5 feet. A total of 339 soil samples and 

457 botanical samples were collected. Wherever possible, soil and botanical samples were collected at the same site to permit comparison 

of the results of the two prospecting methods.

Three hundred fifty-one samples were collected from the copper and 

uranium deposits of which 210 samples were submitted for chemical
346 CONTRIBUTIONS TO THE GEOLOGY OP TJBANIUM

analyses, 22 for semiquantitative spectrographic analyses, and 5 for 

mineral identification by X-ray diffraction techniques. About 70 

polished sections, 6 thin sections, and several heavy-mineral concentrates were studied. Four autoradiographs were made and studied. 

Several samples of uranium ore have been submitted for age determination but the results are not yet available. The field work was accomplished during 5 months in the summer and fall of 1953 and 2 

weeks in the following spring.

ACKNOWLEDGMENTS

All analytical work was done in the laboratories of thelJ. S. Geological Survey. The spectrographic analyses were made by G. W. Boyes 

and P. J. Dunton, the X-ray analyses by W. F. Outerbridge, the 

equivalent uranium determinations by S. P. Furman and E. J. Fennelly, and the selenium analyses were made by J. L. Siverly. Chemical 

analyses for copper, uranium, and vanadium were made by E. C. 

Mallory, J. W. Patton, W. D. Goss, J. F. Wahlberg, J. P. Schuch, 

Wayne Mountjoy, D. L. Stockwell, E. J. Fennelly, H. E. Bivens, 

J. E. Wilson, D. L. Skinner, and K. F. Dufour. Kapid colorimetric 

analyses for trace amounts of copper and zinc were made by H. E. 

Crowe and J. H. McCarthy.

The plant and soil samples were collected by W. R. Martin. The 

writers are indebted to H. D. Zeller and E. H. Baltz, Jr., who kindly 

loaned their maps, notes, and specimens, and to J. G. McGrath for 

operation of the jeep-mounted auger.

This work is part of the program of exploration for radioactive 

raw materials undertaken by the Geological Survey on behalf of the 

U. S. Atomic Energy Commission.

GEOLOGY 

GEOLOGIC HISTORY

During Pennsylvanian and early Permian time, the Ocate-Guadalupita area was part of a geosyncline, the Rowe-Mora trough, which 

was flanked by rising geanticlines of Precambrian rocks that were part 

of the Colorado Mountains or ancestral Rocky Mountains (Read and 

Wood, 1947, p. 266). The axis of the geosyncline, which trends northwest, was about 12 miles west of the district. The rising positive areas 

furnished large volumes of sediments to the basin, which was occupied 

by a sea during the deposition of most of the Magdalena group. 

Marine sedimentation recurred intermittently during the deposition 

of the lower part of the Sangre de Cristo formation, but most of the 

sediments were deposited under subaerial conditions.

The sea invaded the region repeatedly after the deposition of the 

Sangre de Cristo formation. Bachman (1953) believes that the
COPPER AND URANIUM DEPOSITS, COYOTE DISTRICT, N. MEX. 347

Glorieta sandstone member of the San Andres formation of late 

Permian age is probably a beach sand deposited as the sea transgressed 

northward. Triassic and Jurassic sediments are partly shallow marine and partly continental in origin. A major marine transgression 

lasted during most of Cretaceous time.

In early Tertiary time, regional compression deformed the rocks 

in the district and buckled the site of the present Sangre de Cristo 

Mountain system into a broad anticlinorium. Precambrian rocks 

were moved eastward over the Pennsylvanian rocks along steep reverse faults on the east flank of the rising mountains. The rocks 

within and immediately east of the zone of reverse faults were steeply 

tilted or overturned to form the series of hogbacks in which the district 

is located (Northrup, Sullwold, MacAlpin, and Eogers, 1946; Bachman, 1953). This narrow, upturned belt parallels the east flank of 

the mountains northward and as far south as Las Vegas.

The sedimentary rocks farther east were gently folded to form 

the Jarosa syncline and the Ocate anticline. The axes of these northtrending folds are 3 miles and 6 miles east of Coyote Creek.

Basalt flows belonging to two periods of activity in late Tertiary 

or early Quaternary time covered all older rocks. The older flows 

originally covered most of the district, but only scattered erosional 

remnants exist today.

STRATIGRAPHY

Four main groups of rocks in the Coyote district are: (1) igneous 

and metamorphic rocks of Precambrian age; (2) sandstone, arkose, 

siltstone, limestone, and shale of Pennsylvanian, Permian, and 

Triassic age; (3) basalt flows of late Tertiary or early Quaternary 

age; and (4) quaternary gravel and alluvium. Their distribution 

is shown in the general geologic map of the district in plate 24. A 

graphic section of the sedimentary rocks from Precambrian to the 

Benton formation of Cretaceous age is shown in figure 68. The rocks 

of Jurassic and Cretaceous age are included in figure 68 to provide 

comparison of the stratigraphy of the Coyote district with that of 

other uranium districts. Bachman (1953) gives descriptions of these 

units.

PRECAMBRIAN ROCKS

Precambrian rocks in fault contact with the Magdalena group 

crop out along the west side of the district. These Precambrian rocks 

are chiefly quartzite, containing minor amounts of pegmatite, schist, 

and gneiss. Coarse-grained pink granite, diabase, diorite, amphibolite, pegmatite, and quartz veins are common in the Precambrian areas 

of northern New Mexico and Colorado. Fragments of many of these 

rocks are found in the Pennsylvanian and Permian sedimentary rocks.

417828
348 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

CRETACEOUS

J, 

<o

i-

-' CARBONIFEROUS PCRMIAW rtnwmiN PENNSYLVANIAN 7« 

PRECAMBRIAN

Benton formation

Dakota sandstone

Mornson formation

Wanakah formation ^

Ocate sandstone /

Naranio formation /

Chinle formation

Santa Rosa sandstone

Bernal formation

San Andres formation 

Glorieta sandstone 

member

Yeso formation

Sangre' de Cristo 

formation

Magdalena group

_____-]

-^f^g

J.'iL'^.' T.i:

-' ::~- ::'-^-r.

' : ! ' .- vA.;.'-- .---.-'' 

 ... - 

 ^r=--"-=^:

^7=^7=

^^^=

.~~'V-;'--°

W&S ; ':'? ".:/

 -

; : :.v;_-^-3-r-:

li'^i _ ' '..-

-^ il-.'-'-.-V;::

~ ~rr~^r"^~-^ -

- " ' ~.~r-lEr!E:

-^rL-^r-^z

-_r-_r^--n.^.-^--|

-^r_-_-^_-^^

T.T^.-T.Tt.T.v.r;

i^J^-lL-^/.

Ji :'.' ' ' '..';'-'

^ViVi^y.^

 "" -"- " -

:--ir^r^rw^_-^

^-.WvvT.-

SM

FMfe----

."vi^v.'.y.:

::::P^i.

-U-l'-liJ^'j-1 -

fill

Thickness 

m feet

400

180 

150

 v. 25 

\ 50

640

425

100

266

0-100

3000- 

3300

3500- 

10,000

£ o

"5 O

500 ftexposed but tois probably ]nearer 

Shale, brown to gray, fissile marine, and limestone

Sandstone, buff to gray, medium-grained

Sandstone, brown, and variegated shale, interbedded 

Shale, gray and brown, sandstone, and limestone 

Sandstone, gray, massive, cross-laminated, probably correlative with 

Entrada sandstone 

-Sandstone, brownish-red, siltstone, and shale, interbedded

Shale, brownish-red and maroon, and siltstone, with a few discontinuous sandstone lenses

Sandstone, brownish-red, in part conglomeratic, and shale

Siltstone, brownish-red and fine-grained sandstone 

Sandstone, gray to light-brown, medium grained, cross-laminated in 

part, may mtertongue with Sangre de Cristo formation 

Siltstone, brownish-pink, mtertongues with Sangre de Cristo formation; generally absent north of Lucero

Pebble conglomerate, brownish-red arkosic, sandstone, and shale 

with minor gray shale and limestone, generally correlative with Abo 

formation; basal part mtertongues with upper part of Magdalena 

group

Sandstone, brown and buff, arkosic pebble conglomerate and shale 

interbedded with gray marine limestone, base of exposed section 

in fault contact with Precambnan rock

Quartzite and minor schist, gneiss, pegmatite in area. Granite 

abundant elsewhere

FIOUBB 68. Generalized columnar section of the sedimentary rocks of the Coyote district

and surrounding region.
COPPER AND URANIUM DEPOSITS, COYOTE DISTRICT, N. MEX. 349 

MAGDATENA GROUP 

DESCRIPTION

A regional angular unconformity separates the Precambrian rocks 

from the Magdalena group of Pennsylvanian age. The Magdalena 

group 12 miles west of Guadalupita near Chacon consists of four 

units (Bachman, 1953). The basal unit, 3,800 feet thick, is equivalent 

to the Sandia formation and consists of sandstone and arkose, containing minor amounts of shale and limestone. The next higher unit, 

about 1,000 feet thick, is bituminous and slightly calcareous friable 

and fissile shale. The third unit consists of 2,800 feet of interbedded 

arkose, sandstone, shale, and limestone. The upper unit, 3,000 feet 

thick, consists of brownish to reddish-brown sandstone, arkose, and 

shale interbedded with gray marine limestone.

The section at Chacon is more than 10,000 feet thick and is dominantly marine. Only about 3,500 feet of the upper part of the Magdalena group is exposed in the Coyote district, however. Bachman 

(1953) believes a large part of the Magdalena group is cut out by 

reverse faults along the west side of the district (pi. 24).

The marine sedimentary rocks of the Magdalena group in the 

Coyote district are yellow-brown, buff, or gray in contrast to the 

predominantly reddish continental sedimentary rocks of the Sangre 

de Cristo formation. On a regional scale the marine sedimentary 

rocks of the Magdalena group grade laterally and vertically into red 

beds of the Sangre de Cristo formation (Northrup and others, 1946). 

K. G. Brill (1952, p. 821-823, 826-827), G. O. Bachman (1953), and 

C. B. Eead and G. H. Wood (1947, p. 223-227) give further details 

on the regional stratigraphic relationships of both Pennsylvanian 

and Permian formations.

The contact of the Magdalena group and the overlying Sangre 

de Cristo formation in the district was arbitrarily placed at the change 

from gray or brown to red about 140 feet above a 25-foot fossiliferous 

limestone bed. In other parts of New Mexico the upper contact of 

the Magdalena group is at the top of the highest marine limestone bed, but in this area several thin marine limestone beds occur 

in the lower 950 feet of a red-bed sequence that is indistinguishable 

from the Sangre de Cristo formation.

FOSSILS

The 25-foot-thick limestone bed 140 feet below the contact contains 

abundant marine fossils, including algae (?), sponges, corals, erinoids, 

bryozoans, brachiopods, and mollusks. The fossils listed here were 

identified by members of the Geological Survey (written communications, 1954).
350 CONTRIBUTIONS TO THE GEOLOGY OF UEANIDM

Corals (identified by Helen Duncan)

Caninoid corals (Pseudozaphrentoides as interpreted by Moore

and Jeffords) 

Clisiophyllid corals (NeoJconincJcophyllum as interpreted by

Moore and Jeffords) 

Bryozoans (identified by Helen Duncan) 

Fistulipora sp., massive form 

Polypora sp. 

RTiabdomeson sp.

Brachiopods (identified by Mackenzie Gordon, Jr.) 

Meekellastriatocostata (Cox) 

Dictyoclostus sp.

Linoproductus cf. L. platyunibonus. Dunbar and Condra 

Echinoconchus semipunctatus (Shepard), var. 

Neospirifer cf. N. latus. Dunbar and Condra 

Composita subtilita (Hall) 

Composite,? sp.

Mollusks (identified by Mackenzie Gordon, Jr.) 

Pteria sp. 

Allorisma sp. 

Worthenia sp. (identified by Ellis Yochelson and Brookes

Knight)

The over-all affinities indicate about middle Pennsylvanian or at 

least post-Morrow age (Mackenzie Gordon, Jr., and Helen Duncan). 

The range of the species is little known in New Mexico but there is no 

evidence of a late Pennsylvanian or Permian age.

The species to which Linoproductus and Neospirifer are compared 

are confined to the Kansas City and Lansing groups of the Missouri 

series in Kansas and Nebraska, according to Dunbar and Condra 

(Mackenzie Gordon, Jr.). The corals resemble species from the upper 

Marble Falls limestone and Smith wick shale (post-Morrow lower 

Pennsylvania) of Texas more than other described species (Helen 

Duncan). A scale tree, probably Lepidodendron, found in arkose in 

the upper part of the Magdalena group indicates that marine conditions were not universal.

SANGRE DB CRISTO FORMATION

The Sangre de Cristo formation of Pennsylvanian and Permian (?) 

age overlies the Magdalena group with apparent conformity in the 

Coyote district, but it interfingers with the upper part of the Magdalena group on a regional scale.

DESCRIPTION

In the Guadalupita area, the Sangre de Cristo formation is between 

3,000 and 3,200 feet thick (fig. 69); along the Mora River 6 miles south
COPPER AND URANIUM DEPOSITS, COYOTE DISTRICT, N. MEX. 351

Glorieta sandstone member of 

San Andres formation

Thickness

I deposits In sandstone

Limestone

Sandy limestone 

Shaly limestone

Shale

(V1 -: »':*|

Uranium-vanadium Conglomeratic 

wMsandstone

Silty sandstone

 }- -Marine gastropods

I Uranium deposits in 

[ siltstone or shale

L o

Vertical scali 

in feet

Fusulmids, brachiopods

FIGDRB 69. Composite columnar section of the Sangre de Cristo formation, Coyote district,

Mora County, N. Mex.

of the district, the thickness is 3,300 feet (Bachman, 1953). The formation is divided into six units for convenience of description. These 

units are not shown on the large-scale maps because of the uncertainty 

in tracing individual lenticular beds across faults, covered areas, and
352 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

Top

Siltstone and shale, reddish

Sandstone, reddish, arkosic

Siltstone and shale, maroon and 

purple

Sandstone, gray, arkosic 

Covered

Sandstone, yellowish brown, arkosic. 

copper-bearing, some limy beds

Siltstone, mottled gray and red

Limestone, mottled red and gray, 

sandy

Sandstone, gray and yellowishbrown, thm bedded, copper-bearing and thin limestone pebble 

conglomerate beds

Siltstone, gray

Shale, gray

Sandstone and Siltstone, gray and

yellowish-brown 

Covered

Sandstone, gray, arkosic 

Covered

Sandstone, brown, thin-bedded 

Shale(?), gray, covered 

Sandstone, brown, arkosic

Sandstone, gray and brown, thinbedded, fine-grained, with thin 

gray shale and limestone pebble 

conglomerate beds

Limestone pebble conglomerate, 

grayish-brown, sandy

Siltstone and shale, mottled red, 

purple, and gray

Pebble conglomerate, reddisn, 

arkosic

Covered, chiefly shale and siltstone, red, with discontinuous 

reddish sandstone and arkosic 

pebble conglomerate lenses

Limestone, mottled red and gray. 

with minor shale

Covered

Pebble conglomerate, arkosic

Sandstone, red, thin-bedded, finegrained

Pebble conglomerate,.arkosic

Covered

Pebble conglomerate, arkosic

Sandstone and Siltstone, red, very

fine grained 

Pebble conglomerate, arkosic

Sandstone, siltstone, and limy 

shale, reddish, thin-bedded, 

fine grained

Limestone, gray, massive

Pebble conglomerate, arkosic. 

massive

Shale and siltstone, red

Siltstone, gray, containing malachite

Covered, chiefly siltstone, sandstone, shale and limy shale, red

Siltstone, red

Pebble conglomerate, arkosic, thinbedded

Covered, chiefly siltstone, red 

Pebble conglomerate, arkosic

Shale, siltstone and nodular limestone, red'

Pebble conglomerate, reddish.

arkosic 

Shale, red

Pebble conglomerate, reddish, 

arkosic, massive

Shale, red, with limestone nodules 

Pebble conglomerate, reddish,

arkosic 

Covered 

Pebble conglomerate, reddish.

arkosic, massive

Covered, probably chiefly red shale, 

limy shale, and siltstone

Pebble conglomerate, red, arkosic. 

massive

FIGOEB 70. Columnar section of the main ore-bearing interval, Sangre de Cristo formation,

area D.

areas not mapped in detail. A lithologic description of these units is 

given in table 1.

A detailed columnar section of the middle, or principal ore-bearing 

part, of the formation in area D is given in figure 70. Further details 

of the lithology are shown on the large-scale geologic maps of areas 

A to 0 and E to /, plates 25 through 32. Two notable characteristics
COPPER AND URANIUM DEPOSITS, COYOTE DISTRICT, N. MEX. 353

of the Sangre de Cristo formation shown on these maps are: (1) the 

many abrupt facies changes and (2) the small stagnant basins in which 

the gray and black shale beds were deposited. No bed extends the 

length of the district.

TABLE 1. Description of the Sangre de Cristo formation

Thickness 

(feet)

Conglomeratic sandstone unit 200-280 

Sandstone, reddish gray, friable, massive and crossbedded, conglomeratic, with abundant well-rounded sand grains and chert and 

quartzite pebbles up to 3 inches in diameter. Interbedded with 

some mottled silty limestone and shale. Sandstone in upper half 

weathers to smooth, rounded rim. May include beds equivalent 

to Yeso formation and lower part of the Glorieta sandstone member of San Andres formation. Unmineralized.

Variegated sandstone unit 200-;-250 

Sandstone, gray, brown, and red; medium- to coarse-grained, poorly 

sorted, arkosic, fluviatile. Interbedded with thin red shale, siltstone, and limestone. Many cut-and-flll structures and abundant 

fragments of limestone, quartz, quartzite, siltstone, greenstone, 

and vein quartz. Unmineralized.

Red siltstone unit 530-640 

Shale and siltstone, predominantly red, maroon, or chocolate; limy 

or micaceous. Many thin beds of silty limestone and fine-grained, 

red, silty sandstone. Some silicified wood at base. Unmineralized.

Fluviatile sandstone unit 140-300 

Sandstone, gray or brown, well-sorted, thin-bedded, cross-bedded, or 

massive, fine- to medium-grained. Interbedded with thin gray 

shale, limy shale, and limestone pebble conglomerate. Sand-filled 

scours and channels common. Beds lenticular; some beds, limy; 

poorly sorted, coarse, with abundant clay fragments, carbonized 

wood, and foreign rock fragments. Uranium, vanadium, and 

copper deposits (pis. 26 and 29).

Transition unit 670-940 

Arkosic pebble conglomerate, reddish gray, massive, alternating 

with red, gray, or black, micaceous, carbonaceous, or limy shale 

and siltstone. Many thin limestone and limy shale beds in upper 

part. Carbonized or silicified wood locally abundant. Copper in 

local gray or black lenses at 10 horizons; some uranium (pis. 27 

and 31).

Red arkose unit 630-950 

Arkosic pebble conglomerate, reddish gray, 20 to 80 feet thick. 

Coarse, massive beds alternating with red, chocolate, or maroon, 

shale, limy shale, and micaceous siltstone. Few thin limestone 

beds, some fossiliferous and marine. Arkose contains abundant 

angular quartz, feldspar, and granite fragments up to % inch in 

diameter, carbonized, silicified or calcitized wood and magnetite 

seams along the bedding. A thin gray micaceous uraniferous 

shale or siltsone bed in areas A and C. Some copper-bearing carbonaceous shale (pis. 25 and 32).
354 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

FOSSILS

Carbonized plant remains and fossil wood replaced by silica, calcite, chalcocite, or, rarely, pink barite are the most common and 

widely distributed fossils in the Sangre de Cristo formation. Especially well-preserved plant remains are found in pit G2 and in the 

uraniferous siltstone in area A.

A Permian (?) conifer, LebacMa, was reported by Zeller and Baltz 

(1954, p. 3) in the northernmost pit in area #, and CcHamites and 

Lepidodendron have been tentatively identified by the writers.

Some f ossilif erous marine limestone or siltstone occurs in the lower 

950 feet of the formation. Brachiopods, pelecypods, crinoids, nautiloids, and gastropods, chiefly bellerophontids, have been collected. 

The marine fossils have been identified by members of the Geological 

Survey as follows:

TABLE 2. Marine fossils of the Sangre de Cristo formation

Fossil Locality Identified by

Linoproductus sp_________________ 112 (pi. 32)____ Mackenzie Gordon, Jr.

Myalina sp___-_-________________ BZ-21 (pi. 24)_ S. A. Northrup

Pelecypods indet.______________ 16 (pi. 32)_____ E. L. Yochelson

Hypselentomat sp_________________ 16 (pi. 32)_____ Do.

Bellerophontid gastropods indet_-_- 16 (pi. 32)_____ Do.

Pseudorthoceras cf. P______________ i6 (pi. 32)_____ Mackenzie Gordon, Jr.

knoxense (McChesney)______ 16 (pi. 32)__.__ Do.

Some of the copper-bearing shale either contains marine fossils or is 

overlain by f ossilif erous limestone. The genus Hypselentoma is known 

only from the upper Pennsylvanian in the mid-continent region 

(Yochelson, written communication, 1954). If the range is the same 

in the Coyote district, at least the lower 950 feet of the formation is 

Pennsylvanian.

CONDITIONS OF DEPOSITION

Most of the Sangre de Cristo formation appears to be first-cycle 

sediments deposited in a deltaic, flood plain, or fluviatile environment 

near the source areas, which were high during the deposition of the 

lower units of the formation. Thin, marine limestone beds show that 

the basin of deposition was intermittently below sea level. The thickness and grain size of the coarser beds decreases upward, and the 

proportion of limestone or shale increased as the relief of the source 

areas became lower. The lower two units show a cyclic sequence of 

sediments; these have been called cyclothems of the piedmont type.

Locally, especially during deposition of the transition unit, swamps, 

lagoons, and stagnant ponds existed on the flood plain. According 

to Yochelson (written communication, 1954), the abundance of 

Hypselentoma (?) in a limestone bed at pit i6 and the presence of
COPPER AND URANIUM DEPOSITS, COYOTE DISTRICT, N. MEX. 355

very few other marine fossils could indicate a shallow-water environment with restricted circulation of sea water.

The sandstone of the fluviatile sandstone unit (table 1) was ap-^ 

parently deposited in the channels of meandering streams on a flood 

plain. The coarse, poorly sorted, conglomeratic sandstone beds abovet 

the red siltstone unit may indicate renewed uplift or a new source area.. 

The uppermost unit appears to be a series of beach deposits on an area, 

being gradually inundated.

YESO FORMATION

The Yeso formation of Permian age pinches out near Lucero and 

is not present in the mapped area. It consists of brownish-pink siltstone that is lighter and finer than the Sangre de Cristo formation. 

The description of this and succeeding units is from Bachman (1953).

SAN ANDRES FORMATION (GLORIETA SANDSTONE MEMBER)

The Glorieta sandstone member of the San Andres formation of 

Permian age is the only member of the formation exposed in the district. The member consists of about 266 feet of gray to light-brown, 

medium-grained sandstone. It forms the prominent cliff along the 

east side of the district.

BERNAL, FORMATION

The Bernal formation of Permian age consists of interbedded 

brownish-red siltstone and fine-grained sandstone about 100 feet thick. 

A disconformity separates the Bernal formation and the Glorieta 

sandstone member of the San Andres formation.

SANTA ROSA SANDSTONE

The Santa Rosa sandstone of Late Triassic age is exposed in the 

southeast corner of the area (pi. 24), lying disconformably on the 

Bernal formation. It consists of 425 feet of brownish-red shale and 

sandstone. The units above the Santa Eosa sandstone are not exposed in the district and are not described although they are included 

in figure 68.

QJTATERNARY(?) BASALT

Five volcanic centers are present a short distance northeast of 

the Coyote district. The nearest is less than a mile east of the north 

end of the district. Two ages of extensive basalt flows (Bachman, 

1953) cover large areas along the east and north sides of the district. 

The older flows originally covered the Coyote district but only remnants now exist as mesa cappings on vertical beds of older rocks 

(pi. 24). The five volcanic plugs and the flow rocks (Bachman, 1953) 

in the Ocate area are products of the later period of eruption. No 

evidence has been found of a genetic relationship between the basalt 

and the mineral deposits.

417829 58 3
356 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

STRUCTURE

The Coyote district is in a Laramide( ?) belt of deformation along 

the east flank of the Sangre de Cristo Range. The rocks east of the 

district are warped into gentle folds; the rocks west of Coyote Creek 

are turned up sharply along a north-south axis. In the mineral belt 

the dips are steep to overturned and farther west the beds are overturned and cut by steep reverse faults. Bedding attitudes within the 

mineral belt indicate that the forces of deformation were torsional, 

increasing in intensity northward. The strike changes progressively 

northward from N. 20° W. to N. 20° E. (pi. 24). At the south end 

the beds dip 80° E. Northward the dip passes through the vertical, 

and the overturned beds in the northern part dip 50°-756 W. The 

degree of overturn increases westward throughout most of the district.

Several high-angle reverse faults were mapped by Bachman (1953) 

in Precambrian and Pennsylvanian rocks along the west side of the 

district. The Precambrian rocks have been thrust eastward several 

thousand feet over Pennsylvanian rocks, cutting out a large part of 

the Magdalena group.

Several northwest-striking oblique faults with lateral displacement of less than 300 feet were mapped in areas A, E, and -F (pis. 25, 

28,29). Several minor northeast-striking oblique faults were mapped 

in area H (pi. 31). Some faults clearly offset the ore zones; however, 

the lack of marker beds makes correlation across the faults difficult. 

The arkose is sheared and bleached in areas of closely spaced faulting. 

Although several ore deposits are near major faults there is no evidence of mineral deposition along the faults (pis. 28 and 29).

MINERAL DEPOSITS

The mineral deposits of the Coyote district (pi. 24) are confined 

to lenticular beds of gray, brown, black, or pink sedimentary rocks 

in the lower 2,000 feet of the Sangre de Cristo formation. Copper 

and uranium minerals have not been found in the red, chocolatecolored, or maroon rocks that make up most of the formation.

The ore minerals are sparsely distributed, and individual deposits 

are small. Copper deposits typically contain negligible amounts of 

uranium and the uranium deposits contain small but variable amounts 

of copper.

Uranium deposits occur in sandstone and micaceous siltstone; copper 

deposits occur in several rock types, but most of the ore bodies are 

in black carbonaceous shale. The fluviatile sandstone unit (table 1) 

contains most of the uranium deposits. Most of the copper deposits 

are in lower units, particularly the transition unit.

The location of the mineral deposits and samples are shown on 

the large-scale maps, plates 25-32. The analytical data for samples
COPPER AND URANIUM DEPOSITS, COYOTE DISTRICT, N. MEX. 357

from each, area are given in tables 3-9. The location of the scattered 

samples outside these areas are shown in plate 24 and analyses are 

given in table 10.

COPPER DEPOSITS

DESCRIPTION

Copper deposits occur in four types of rock: (1) carbonaceous shale 

orsiltetone, (2) arkosic pebble conglomerate, (3) micaceous sandstone, 

and (4) nodular limy shale or limestone. The deposits are richest 

and most abundant in black, carbonaceous shale lenses and in adjacent 

parts of gray shale or arkosic pebble conglomerate beds. Sandstone 

normally contains low-grade disseminated deposits, and copper deposits in limestone are rare and unimportant.

TABLE 3. Analytical data for samples from area A (pi. %5)

(Radioactivity analyses by S. P. Furman and E. S. Fennely. Chemical analyses byH. E. Blvens, R. F. 

Dufour, E. C. Mallory, C. E. Thompson, D. C. Stockwell, J. H. McCarthy, J. F. Wahlberg, and W. D. 

Goss]

Field

no.

9?,

°3

<>4

194

19^

196

197

198

19Q

?no

"901

?m

ms

?04

?05

?06

207

?os

?09

210

?ii

312

213

?14

Width

(ft.)

2.0

2.7

3.2

.6

2.8

2.3

2.5

1.4

1.0

2.4

2.4

3.0

1.5

2 7

2.4

2. 1

2. 1

3. 5

3. 5

2.8

.9

2.0

ell

0.007

.004

.007

.013

.004

.008

.011

.004

.044

.005

.011

.010

.008

.011

.008

.012

.015

.009

.009

.002

.003

019

Percent

U

0.005

.004

.008

.003

.006

.029

<. 005

.006

.005

.004

.007

.005

Cu

5.07

.13

.07

. 10

. 15

. 10

. 10

.15

. 10

.10

.20

.20

. 15

.07

. 15

.10

.07

.07

. 10

. 10

Se

(ppm)

2

Lithologic description

Green sandstone and shale.

Black carbonaceous shale.

Altered limonitie sandstone.

Buff and gray shale.

Buff siltstone, brown shale.

Buff sandstone and gray siltstone.

Gray-brown siltstone.

Yellow-brown siltstone and shale.

Yellow-brown micaceous siltstone.

Yellow-brown shale and siltstone.

Yellow-brown siltstone with plant

remains. 

Do.

Do.

Yellow-brown shale and siltstone.

Olive-brown siltstone.

Do.

Gray-green siltstone and shale.

Dark gray-green siltstone with shale.

Gray-green and olive-brown shale

and siltstone.

Gray shale.

stone with carbon seams.
358 CONTRIBUTIONS TO THE GEOLOGY OF TJBANIUM

TABLE 3. Analytical data for samples from area A (pi. 25) Continued

Field

no.

215

21 6

217

219

220

221

222

223

224

225

226

281

233

234

235

236

237

238

239

240

241

242-

243

244

245

400

401

402

403

404

405

412

228

Width

(ft.)

1.6

1.4

1 9

q

1.8

2.7

.8

1.6

1.6

1.2

q

.7

1.2

q

1.7

1,6

2.6

1.0

3.3

2. 1

1.8

.8

:), .8

2.0

1.0

2.0

6.0

3.5

2.5

3.3

2.0

eU

0.004

.019

.006

.004

.004

.007

.006

.006

.022

.016

.013

.018

.021

. Oil

. 012

,026

.006

.020

.011

.006

,012

.008

. 012

,002

.002

.005

.004

.002

.002

.004

.008

Percent

U

.021

.011

.007

.012

.014

.008

. 009

. 015

.015

.009

.007

.002

.007

Cu

0.07

. 15

, 10

.03

.06

.05

.02

.36

,17

.29

. . 16

.20

,54

.29

.60

3.92

1.75

. 14

.05

. 18

Se

(ppm)

2

5

-

Lithologic description

Gray and black silty sandstone.

Do.

Do.

Gray-green and olive shale.

Yellow-brown siltstone and shale.

Gray micaceous siltstone and shale.

Chalcocite nodules.

Fossiliferous limestone.

Grav-green shale.

Gray-green shale with carbon seams.

Siltstone with calcite, quartz, plagioclase, nontronite, and kaolinite.

Gray-green shale and yellow-brown

sandstone.

bon. 

Do.

Yellow-green micaceous sandstone.

Micaceous sandstone.

Yellow-green micaceous sandstone.

Do.

Dark-green micaceous shale, yellowbrown sandstone. 

Gray-green shale and carbon seams,

yellow-brown sandstone. 

Dark-green and black shale.

Fine-grained sandstone.

Blue-gray arkosic sandstone.

Black shale and arkosic sandstone.

Composite of 401 and 402.
COPPER AND URANIUM DEPOSITS, COYOTE DISTRICT, N. MEX. 359

TABLE 4. Analytical data for samples from area B (pi, 26)

[Radioactiyity analyses by 8. P. Furman. Chemical analyses by E. C. Mallory, J< F. Wahlberg.Wayae 

Mountjoy, S. P. Schuch, H. E. Crowe* W. D. Goss, and J. H. McCarthy]

Field 

no.

247

248

249

251

330

331

332

333

334

335

336

352

Width 

(feet)

1.0

.6

.6

.8

1.2

1.2

.4

.5

.5

Percent

eU

0.051

.058

.061

. 11

.052

.022

.043

.048

.030

.024

.26

u

0.036

.049

.041

. 10

.044

.017

.033

.024

.033

.018

.29

Cu

0.79

1.37

1.22

.01

.77

.02

.62

1.66

.25

.63

.47

v,o.

_

0.32

<. 1

.12

.15

<. 1

<.l

.22

Lithologic description

Coarse gray-brown arkosic sandstone

with malachite.

Brown and yellow-brown, fine-grained,

thin-bedded arkosic sandstone with

malachite.

Same as 248 with sulfides.

Gray-brown arkosic sandstone with

chalcopyrite and calcite cement.

Carbonized-ocherous log.

Pink arkosie sandstone with chalcopyrite.

Pink-gray arkosic sandstone.

Gray arkosie sandstone.

Black and brown sandstone.

Arkosie sandstone.

Pink feldspathic sandstone.

Pink arkosie sandstone with chalcopyrite and metatyuyamunite.
360 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

TABUS 5. Analytical data for samples from area 0 (pi. 127)

{Radioactivity analyses by S. P. Furman and E. J. Fennelly. Chemical analyses by D. L. Skinner, J. H. 

McCarthy, W. N. Niles, Wayne Mountjoy, J. P. Schuch, H. E. Bivens, R. F. Dufour, E. C. Mallory, 

C. E. Thompson, D. L. Stoekwell, and J. F. Mallory]

Field 

no.

58 

59 

60 

65

66 

67 

68 

69 

70 

71 

72 

73 

337

.. 338 

339 

340 

341 

342 

414 

415

416 

417

418 

419 

420

BZ-1 

BZ-2

BZ-3 

BZ-4

Width 

(feet)

3.4 

2.0

4.0

1.0 

1.3 

1.7 

1.7 

.6 

2. 1 

.6

4. 1 

2. 1

1.5

.9 

.6

2.0

Percent

eXJ

0.004

.004

.006

.008 

.005

.01

.008 

.005 

.004 

.005 

.007 

.016

.019 

.034

.010 

.023 

.003

.009 

.007

.020 

.007

U

0.004

.005 

.003

.004

.002 

.001 

.001 

.001 

.004 

.009

.012 

.016

.006 

.011 

.002

.006 

.007

.004 

.003

Cu

0. 15

.88

2.38 

2.14

2.63

1.01 

1. 91 

1.61 

1.94 

1.04 

.09

.08 

.56

.02 

.20 

.05

2.21 

1.73

2.51 

2.72

V,0s

<0. 1

<. 1 

<. 1

<.l

.17

Se 

(ppm)

2

2 

2

Lithologic description

Chalcocite nodules. 

Gray-green shale. 

Do. 

Dark gray micaceous siltstone. 

Black carbonaceous shale. 

Wood replaced by chalcocite. 

Chalcocite nodules. 

Large chalcocite nodules. 

Black carbonaceous shale. 

Gray-green shale. 

Chalcocite nodules. 

Do. 

Black shale with chalcocite 

nodules. 

Do. 

Do. 

Do. 

Do. 

Do. 

Cross-bedded silty sandstone. 

Yellow - brown micaceous 

sandstone. 

Yellow sandstone. 

Gray-green shale and yellow 

sandstone. 

Micaceous sandstone. 

Do. 

Yellow - green micaceous 

sandstone. 

Dark - gray carbonaceous 

shale. 

Arkosic sandstone with chalcoeite and malachite. 

Black carbonaceous shale. 

Black carbonaceous shale 

with chalcocite nodules 

and carbonized plant remains.
COPPER AND URANIUM DEPOSITS, COYOTE DISTRICT, N. MBX. 361

TABLE 6. Analytical data for samples from area E (pi. 28}

(BadiSaetivity analyses by S. P. Furman and E. J. Fennelly. Chemical analyses by D. L. Skinner, 

J. H. McCarthy, W. N. Niles, Wayne Mountjoy, J. P. Schuch, W. D. Goss, H. E. Bivens, B. F. Dufcrar, 

E. C. Mallory, and C. E. Thompson]

Field no.

40 

41 

42 

43 

44 

45

46 

47

48 

91

97 

98

99

itio

101 

102 

103 

104

BZ-7 

BZ-8

BZ-9 

BZ-10 

BZ-11 

BZ-12

BZ-13 

BZ-14

Thickness 

(feet)

5.5

5.0

2.4 

.5

.9 

1.7 

1. 1

Percent

eU

0.008

.003

.006

.005

.003

.005

.004 

.002

.005 

.010

.004 

.005 

.011

.014 

.065

.039 

.001 

.001 

.011

.018

U

0.002 

.009

.004 

.009

.010 

.048

.018 

.001 

<. 001

.008

.015

Cu

2.74

4.08

1.46

.49 

.15

.22

4.65

.91 

1.34 

5.81

4. 16 

6.39

14.38

.03 

3.72

4.65

Vj05

<0. 1 

< 1

< 1

.26

.30 

. 18 

<-l

Se 

(ppm)

<2

<2

<2

10

<2

3 

3

1

Lithologlc description

Gray carbonaceous shale. 

Black arkosie sandstone. 

Chalcocite in sandstone. 

Do. 

Arkosie sandstone. 

Black arkosie sandstone 

with malachite and 

volborthite. 

Chalcocite nodules. 

Green shale and sandstone. 

Gray sandstone with 

malachite and volborthite. 

Chalcocite and metatyuyamunite in sandstone. 

Gray silty sandstone. 

Yellow-brown silty 

sandstone. 

Gray micaceous silty 

sandstone. 

Green micaceous siltstone. 

Do. 

Do. 

Do. 

Argillized arkosie sandstone. 

Arkosie sandstone. 

Arkosie sandstone with 

metatyuyamunite. 

Do. 

Barren olive clay shale. 

Barren gray clay shale. 

Shale and arkosie sandstone. 

Black carbonaceous 

shale. 

Radioactive coaly fragment may contain 

uraninite(?).
362 CONTRIBUTIONS IK) GEOLOGY OF ITRANIUM

TABLE 7. Analytical data for samples from area F (pi. 29)

jRadioactivity analyses by S. P. Furaan and E. J. Fennelly. Chemical analyses by D. L. Skinner, 

. J. H. McCarthy, H. E. Bivens, fi. F. Dufour, E. C. Mallory, 0. E. Thompson, J. E. Wilson, D. L. 

Stockwell^W. 6. Goss, J. F. Wahlberfc, and?. L. Silverly]

Field

no.

14

17

18

33 

34

35

36 

61

74

75

76

77

81

82

83

R4

85

86

87

88

89

90 

95

96

107 

108 

109 

110

111 

112

Width

(feet)

2. 0

2,0

 

2.3

.8 

.7 

1.4 

.9

1.8 

.8

eU

0.002

.062

.001

.081 

.082

.005

.014

.005 

.009 

.005 

.002

.025 

.013

Per

Tf

 

 

0.008

.002 

.006 

.003

.017 

.012

sent

Cu

0.06

.02

.45

1.23

.66

.17 

.60 

.33 

1.72

2.09 

1.33

VaOs

 

0.45

<.l 

< ! 

< ! 

< !

<-l

<-l

Se

(ppm)

 

10

2 

2 

2 

2

10 

2

Lithologic description

Green shale with carbon.

Coaly seam in sandstone.

Red micaceous siltstone.

Metatyuyamunite 'specimens.

metatyuyamunite. 

Chalcocite nodules.

Green nodular limestone. 

Black and green arkose.

Reddish arkose and sandstone. 

Weathered carbonaceous material. 

Black vanadiferous(?) sandstone. 

Do.

Nodular recrystallized limestone. 

Gray sandstone with bornite.

Black sandstone with vitrain

and metatyuyamunite. 

Ocherous-orange core of log.

Radioactive limonitic sandstone. 

Radioactive carbonized log.

Do.

Black and yellow-brown

sandstone. 

Limonitic sandstone core of

log. 

Green sandstone with 

carbon. 

Green siltstone and sandstone. 

Yellow-green uranium mineral. 

Black and red shale. 

Black carbonaceous shale. 

Do. 

Gray-green micaceous siltstone. 

Black shale and arkosic 

sandstone. 

Olive siltstone and black 

shale.
COPPER AND URANIUM DEPOSITS, COYOTE DISTRICT, N. MEX. 363 

TABLE 7. Analytical data for samples from area F (pi. 29) Continued

Field 

no.

113 

114 

116

176 

177

178 

179 

186

187

188 

343 

344

345 

346

347

349

350 

351 

353

354 

355

356

357 

BZ-15

BZ-16

BZ-17 

BZ-18

BZ-19

Width

(feet)

3.5 

3.5

1.4

3.4 

1. 1 

2. 0

1.8

1.3 

2. 1

1. 2

2.0 

2.2 

1.3

1.0 

1.2 

1.3

1. 4

. 6 

1.6

Percent

eU

0. 004 

.005 

.007

.003 

.005 

. 18

.063

.009 

.015 

.042

.075 

.046

.038 

.20

.038 

.044 

. 068

.025 

.81

.035

.010 

.068

.004 

.054

.039

u

0.004 

.005

.004 

.004 

.20

.042

.006 

.006 

.027

.038 

.041

.024 

.18

.033 

.036 

.019

.019 

.85

.026

.003 

.067

.0002 

.032

.026

Cu

0.06 

.3 

.58

.2

1.27

.89

.72 

.02 

. 10

. 17 

.09

.09 

.20

.02 

.02

13.65

57.33 

.66

.41

VaOs

< 1

. 29 

.90

1. 22 

1.36

.32 

2.07

< 1 

< 1

2.92

Se 

(ppm)

<2

3

50

Lithologic description

Chalcocite nodules. 

Black shale. 

Red, gray, and green shale. 

Gray, black, and olive shale. 

Olive and gray-green siltstone. 

Olive, gray, and black shale. 

Olive and black shale. 

Pink arkosic sandstone, micaceous siltstone with 

metatyuyamunite. 

Pink sandstone and black 

shale. 

Olive-brown and black shale. 

Arkosic sandstone. 

Conglomeratic sandstone 

with black clay fragments. 

Pink conglomeratic arkosia 

sandstone. 

Gray-brown arkosic sandstone. 

Pink feldspathic sandstone. 

Selected high grade, abundant metatyuyamunite. 

Pink arkosic sandstone. 

Do. 

Pink arkosic micaceous sandstone. 

Arkosic sandstone and black 

shale. 

Selected high - grade ore,, 

abundant metatyuyamunite. 

Pink arkosic micaceous sandstone. 

Arkosic micaceous sandstone 

Sandstone with carbonized: 

wood. 

Acicular limestone nodule& 

with malachite. 

Chalcocite nodules. 

Sandstone with disseminated malachite and metatyuyamunite. 

Sandstone with disseminated metatuyuamunite.

417829 58
364 CONTRIBUTIONS TO THE GEOLOGY OP URANIUM

TABLE 8. Analytical data for samples from areas G and H (pis. 30 and 81}

rman and E. J. Fennelly. Chemical analyses by D. L. Skinner, T 

Schuch, W. D. Goss, E. C. Mallory, 3. L. Siverly, C. E. Thompson,

[Radioactivity analyses by 8. P. Furman and E. J. Fennelly. Chemical analyses by D. L. Skinner, W N. Niles, Wayne Mountjoy, J. P. ~ ' ------ __-_-- - - - - - - 

and D. L. Stockwell]

Field

no.

1

2

3

4

5

6

7

8

9

10

11

12

14

15

16

166 

167

168

169

170

171

172

174

175

184

185

189 

190 

191

192 

193 

BZ-25

BZ-26

BZ-30

Thickness

(feet)

6.0

7.0

2.0

.5

4.2 

2.0

2. 4

4. 0

2.5

2.5

2.0

3.5

6.5

6.3

3.2

.4 

1.5 

3.8

3. 2 

2.0 

1. 5

eU

0. 003

.015

.005

.011

.001

.004

.002

.002

.009

.001

.006

.004

.002

.005

.006

.007 

.003

.005

.004

.003

.003

.002

.003

.004

.002

.003

.022 

.005 

.003

.008 

.007 

.008

. 048

. 015

Percent

TJ

0.015

.005

.006

.019 

.001

.005 

.006 

.004

. 041

.008

Cu

0.63

6.07

.03

1. 40

1.97

55.73

.49

.06

1.27 

. 37

1. 21

.06

. 60

1.49

.05

.03

.015

.005

.005

1.09 

3.53 

. 1

1.05

.58 

7.49

32. 85

.80

Lithologic description

Gray carbonaceous shale.

Chalcocite nodules.

Limestone.

cocite.

Barren red micaceous siltstone.

Black carbonaceous shale.

Wood replaced bv chalcocite.

Gray carbonaceous siltstone.

Do.

Chalcocite nodules.

Gray and black shale. 

Gray brown siltstone.

Black carbonaceous shale.

Black carbonaceous shale.

Do.

Gray and red shale.

Gray shale.

Black shale and arkose. 

Black carbonaceous shale. 

Gray green siltstone.

Gray and black shale. 

Green and black shale. 

Gray shaly siltstone with carbon and 

chalcocite. 

Selected radioactive chalcocite nodules

with uraninite.

nodules.
COPPER AND URANIUM DEPOSITS, COYOTE DISTRICT, N. MEX. 365

TABLE 9. Analytical data for samples from area I (pi. 8£)

[Radioactivity analyses by S. P. Furman and J. H. Patton. Chemical analyses by D. L. Skinner, W. N. 

Niles, Wayne Mountjoy, S. P. Schuch, H. E. Bivens, W. D. Goss, R. F. Dufour, J. L. Siverly, and 

E. C. Mallory]

Field

no.

122

123

124

125

126

127 

128

129

130

131

132

133

134

135

136 

137

138

139

141

142

143

144

145

146

147

148

149

150

151

152

153 

154 

155 

156

157

158

159

160

161

162

BZ-28 

BZ-29

Width

(feet)

2.5

3.5

1.7

2.0

1.3

2.0 

3.0

2.0

1.2

1.3

2.0

2.7

2.0

3.4

1. 5

2.7

2.0

1.0

1.9

4.8

2.0

5.0

. 8

.6

4. 2

3. 5

2.4 

2.0 

1. 6

1.0

2. 7

1. 1

2.2

3.0

.3

. 5

eU

0.004

.004

.003

.004

.005

.009 

.003

. 003

.004

.005

.005

.002

.004

.004

.012 

.005

.004

.003

.004

.003

.004

.003

.004

.002

.005

.008 

.008 

.007 

. 005

. 003

.005

.007

.003

.004

.054 

.011

Percent

U

0.006

.008

.005 

.005 

.005

.061 

.003

Cu

0. 14

.32

.05

.02

.03

.75 

.02

.02

.01

.01

<.01

<.01

.01

.65

2. 10

.81

1. 52

1. 47

1.79

.01

.07

.01

. 54

.66

1. 57

1.74 

1. 46 

1. 85 

5.20

.02

2. 04

1. 55

1.44

.05

3.84 

2.23

Lithologic description

Gray-green carbonaceous shale.

Do.

Olive-brown micaceous shale.

Gray-brown and gray-green shale.

Gray-green micaceous siltstone.

Gray-green micaceous siltstone.

Do.

Do.

Gray-green siltstone. 

Black carbonaceous shale.

Green micaceous siltstone.

Green siltstone.

Gray-green micaceous siltstone.

Linoproducts sp. (brachiopod) .

Log, partly replaced by chalcocite.

Gray-green clay shale.

Carbonaceous shale and siltstone.

Do. 

Carbonaceous sandstone and siltstone. 

Carbonaceous shale.

Dark-gray and brown shale.

Gray shale and arkose.

Gray shale with red mottling.

tropods. 

Gray shaly sandstone. 

Carbonaceous siltstone and shale.
366 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

TABLE 10. Analytical data for samples outside areas of large-scale maps

[Samples listed in order of appearance on map (pi. 24) from south to north. Radioactivity analyses bjr 

S. P. Furman and E.J. Fennelly. Chemical .analyses by D. L. Skinner, J. H. McCarthy, W. N.Nilesr 

Wayne Mountjoy, J. P. Schuch, and W. D. Qoss]

Field

no.

BZ-31

BZ-32

8

163

164

165

BZ-27

BZ-24 

20

21 1

BZ-22

BZ-23

BZ-21

25

BZ-2Q

26 !

27

28

29

31

32

53

54

52

49 1

50 !

51

BZ~Q

BZ~5

55

56

57

Width

(feet)

1. 5

1.0

1. 4

2.0

1.2

1.2

3.0

5.7

3.0

8.7

ell

0.003

.004

.002

.002

.003

.003

.003

.003

.003

.005

.001

.009

. 003

.004

. 001

.003

.003

.003

.004

.005

.003

.003

.003

.002

.018

.009

.005

Percent

U

0. 002

.003

.002

<.001

.003

.004

. 001

.014

Cu

5. 24

6.76

1 Q7

.01

. 19

.06

.02

.005

1. 06

.005

1.81

2.00

3.46

1. 27

.08

0. 84

.02

.76

.005

6. 13

Lithologic description

Sandstone with carbon.

Dark-gray carbonaceous clay shale.

Light and dark-gray shale.

Gray shale with carbon.

Greenish-gray clay shale.

Barren greenish-gray clay shale.

Fossiliferous limestone.

Marine fossils in sandy limestone.

Do.

Greenish-gray clay shale.

Gray-green and red shale.

Carbonaceous shaly sandstone.

Gray-green carbonaceous shale.

Do.

Light arkosic sandstone.

Mineralized carbonaceous wood.

Gray carbonaceous shale.

Red siltstone, gray micaceous shale.

Gray-green siltstone and shale.

Brown fine-grained sandstone.

Green shale with copper.

Do.

Gray-green shale with copper.

Greenish-gray clay shale.

Black carbonaceous shale.

Carbonaceous shale.

Gray-green shale from dump.

Chalcocite nodules and replaced wood.

1 Semiquantitative spectrographic analyses given in table 11.

The copper deposits are confined to sedimentary rocks that probably were deposited in small, stagnant basins. The association of 

the copper deposits and this sedimentary f acies is so distinct that a 

genetic relationship is indicated. Most of the copper deposits are 

in black shale lenses in the transition unit. The black shale lenses are 

enclosed in gray-green shale that contains a small amount of copper 

and grades into barren red shale or limestone. Detailed sections 

of two typical ore bodies are shown in figures 71 and 72. The sequence 

of rock types shown in figure 71 probably marks successive stages
COPPER AND URANIUM DEPOSITS, COYOTE DISTRICT, N. MEX. 367

t

UJ

o

o

if)

I Oo_

o, 1

z

(^ -) ID O CT) ID ^H

oo CM -^r ID "=r o o

ro in -^r ro no CM -^r

o o o o o o o

o o o o o o o

S

en to
368 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

i oI I I

il IcO1 HO O ID 00 

O LO r-n O LO

01 <-H 

^ O

q o 

o

O O

CM ID ro 00 Is*

CM O O O O

o o o o o

o S
COPPER AND URANIUM DEPOSITS, COYOTE DISTRICT, N. MEX. 369

in the filling of a local basin. The limited extent of the favorable 

host rock, the black shale, limits the size of the ore bodies.

The ore bodies are tabular bedded deposits 100-300 feet in diameter and 1 to 6 feet thick. The copper content ranges from ,1 to 

6 percent. The average ore lens is 2 or 3 feet thick and contains 

about 1.5 percent copper. None of the deposits contains more than 

about 7,500 tons of ore, and few contain more than 1,000 tons.

The ore contains chalcocite nodules less than 2 inches in diameter, 

but some as large as a man's head have been reported. Most nodules 

are not radioactive, although a few highly radioactive ones were 

found at pits G2, E15, and E16.

MINERALOGY

The principal copper minerals are blue and gray chalcocite, 

malachite, and azurite. Azurite and malachite commonly occur as 

disseminated grains or coatings on chalcocite nodules or mica flakes. 

The chalcocite nodules contain small amounts of pyrite, bornite, 

covellite, and vitrain. Uraninite was identified in a chalcocite nodule 

from pit G2, plate 30, by Abraham Rosenzweig of the Atomic Energy 

Commission (Zeller and Baltz, 1954, p. 5). Volborthite is present 

with malachite in a micaceous arkosic sandstone in pit e5, plate 28.

A woody cell structure and even the form of the woody fragments 

are well preserved in many chalcocite nodules (pi. 33), and all stages 

of replacement by chalcocite can be found. Normally the cell walls 

are vitrain and the cores are filled with sulfide minerals. A few 

nodules have a concentric banded structure that may be marked by 

slender groups of pyrite crystals radiating from the center.

Chalcocite also occurs in dense limestone nodules near pits b!4 

and a62. In a few places the dense limestone core of the nodules is 

surrounded by concentric layers of coarse, acicular brownish calcite 

that contains malachite. Chalcocite is rare in sandstone but the outer 

edge of a pebble conglomerate bed adjacent to copper-bearing shale 

may contain as much as 14 percent copper, chiefly chalcocite.

Many coalified woody fragments were composed entirely of vitrain 

and pyrite before pyrite was replaced by copper sulfides. Bornite 

and chalcopyrite are most abundant in nodules that still contain 

abundant pyrite. Covellite and chalcocite are the important minerals 

where replacement is nearly complete (pi. 33). The paragenetic 

sequence is: (1) vitrain and pyrite, (2) chalcopyrite and bornite, 

(3) chalcocite, and (4) covellite. Malachite and azurite are believed 

to be products of weathering. The paragenetic sequence is in the 

order of increasing copper content and decreasing iron content of 

the sulfide minerals. The chalcocite (possibly digenite(?)) is distinctly blue in some nodules where it has almost completely replaced 

pyrite, bornite, and chalcopyrite (pi. 33). The blue color is typical
370 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

of a chalcocite-covellite solid solution, which may contain as much 

as 8 percent covellite at room temperature. The blue chalcocite is 

interpreted by some to indicate a temperature of formation above 

/T5°C (Edwards, 1947, p. 74-76). Copper-bearing samples contain 

less vanadium, lead, and rare earths than uranium samples (table 11, 

page 372).

URANIUM DEPOSITS

URANIUM DEPOSITS IN SANDSTONE

The uraniferous shale and siltstone are of very low grade and all 

commercial-grade uranium deposits are in sandstone. The uranium 

deposits may or may not contain significant amounts of copper or 

vanadium.

Uranium and vanadium minerals are commonly concentrated in 

scours filled by sandstone that contains abundant clay and rock fragments and carbonized wood (fig. 73). Most of the ore pockets are less 

than 2 feet thick and 10 feet long. A group of several closely spaced 

deposits within a favorable sandstone generally are separated from 

other groups by long stretches of barren sandstone. The ore pockets 

are surrounded by lower grade material, and radioactivity may be 

continuous between adjacent deposits. The outcrops of the ore bodies 

are inconspicuous. Metatyuyamunite is locally abundant, but recognizable uranium minerals are not visible in many deposits.

The uranium deposits in sandstone are described below.

Area B, Bias Medina property. All the uranium deposits in area B 

are probably in the same gently dipping arkosic sandstone about 1,670 

feet above the base of the formation. Uranium was found in all the

N. 15° E. S. 15° W.

EXPLANATION

GEIGER COUNTER READINGS

More than 1 5 mr per hr

Geology by D C. Laub and C M Tschanz, 1953 Radioactivity 

analyses by S. P. Furman. Chemical analyses by C. E. 

Thompson, D. L. Stockwell, and E. C. Mallory 

10 Feet

Horizontal and vertical scale

FIGDEE 73. Section along outcrop of ore sandstone, Bias Medina property, Coyote district,

Mora County, N. Mex.
COPPER AND URANIIJM DEPOSITS, : prQT;E ^TBIQTjc K.- 4 _|AEX. 371

trenches except b5 and b7, but ore was found only in trenches bl, b4r 

and the new shaft. The map of these deposits is given in plate 26 and 

the sample analyses are given in table 4.

The ore in pit b4 is in a hard, limy, massive, medium-grained, pink: 

sandstone which fills a scour about 10 feet in diameter. The ore, 4: to 6- 

inches thick, contains abundant small grains of disseminated chalcopyrite ; metatyuyamunite is rare. Chalcopyrite has been found only in. 

area B.

In the summer of 1955 a 15-foot shaft was sunk by lessees about 25 

feet behind the outcrop at pit b4. They reported that the lowest part 

of the shaft cut through several feet of ore containing abundant 

chalcopyrite and as much as 1 percent equivalent uranium. A grab 

sample (360) analyzed in the laboratories of the Geological Survey 

contained 0.78 percent equivalent uranium and 0.41 percent uranium 

(table 11), and duplicate analyses confirmed these figures. The difference between the radiometric and chemical values was surprisinglygreat compared to sample 251 from the nearby outcrop which was; 

nearly in equilibrium. Radiochemical analyses for uranium daughterelements were made by J. N. Rosholt, Jr., to determine the cause of 

the disequilibrium. The radiochemical data (table 11) are interpreted 

to mean that uranium probably has been selectively leached from 

sample 360 even though the sample contains abundant chalcopyrite. 

This conclusion is surprising because uranium has apparently not 

been comparably leached from the surface outcrop (251). If this interpretation is accepted, the ore must have originally contained more 

uranium, perhaps as much as the 1.34 percent required to form the 

ionium in the sample. The indicated subsurface leaching of uranium 

suggests that uranium is readily soluble under certain conditions where 

chalcopyrite is relatively stable. The uranium leached from the ore 

might possibly be redeposited in minable concentrations downdip. 

The only alternative interpretation permitted by the radiochemical 

data would have ionium extracted by the sample from ground waters 

by some mechanism such as coprecipitation with or adsorption on 

ferric hydroxides. This alternative is unlikely.

In pit bl, figure Y3, several sets of cross strata in the sandstone 

are separated by curved, troughlike erosion surfaces. Uranium 

is concentrated along clay seams, in clay fragments, or along discontinuities between cross strata. In the spring of 1954, radioactive 

material was discovered in two massive, grayish-pink arkosic sandstone beds from 1,000 to 1,300 feet north of pit bl. The sandstone 

beds, 6-8 feet thick, are separated by 20 feet of siltstone. Fine-grained 

malachite, the only visible ore mineral, is probably derived from 

chalcopyrite. The radioactive layer in the center of each sandstone 

bed is 1-2 feet thick. Readings as much as 0.2 milliroentgens per hour 

on the Geiger counter were obtained, but samples were not collected.
TABLE 11. Spectrographic, chemical, and radioactivity analyses of selected copper and 

N. Mex. 1

[Samples arranged in groups by rock types, in order of decreasing uranium content. Spectrographic analyses b

by S. P Furman and E. J. Fennelly. Chemical analyses by D. L. Stockwell, J. F. Wahlberg, E. O. Mall

Wayne Mountjoy, H. E. Orowe, N. E. Bivens, and E. F. Dufour]

Field 

no.

355 

186

33 

352

3602 

349

346 

251

89 

149A

201

416

216 

70

337 

40

60 

49* 

50*

Trench 

no.

fll 

fll

f9 

bl

near b4 

f26

f26 

b4

F9 

115

a!9 

c6

a!7 

C6

06 

E15

O19

Lithologic description

Pink micaceous sandstone, abundant carbon, metatyuyamunite 

Ge O.OOX -_ ._._ __ ._

Micaceous sandstone and shale, 

carbonaceous shale, metatyuyaPink micaceous arkosic sandstone,

Pink arkosic sandstone with chalcopyrite and black uranium minDo., bottom new 15 ft. shaft, 25 ft.

Coarse pink arkosic sandstone with 

black clay galls and metatyuy-

... ..do. . . .. ..........

Nonmagnetic heavy mineral concentrate of pink, arkosic sandstone with black uranium minLimonitic sandstone from center of 

carbonized log. P O .X; As O. X._ 

Carbonized log replaced by chalcocite. BiO.OOX.... ____________

Buff micaceous siltstone and shale.. 

Buff micaceous siltstone and sandBlack carbonaceous shale with

_____do..__________..__.______.._.___

Gray or green shale with toe carbonized plant remains and copper .

-___do_._. -_._.-. ...............

.. do..............................

Percent

eU

0.81

.18 

.081

.26

.78

.20 

.046

Ml

.004

.044

.019 

.019

.008 

.010

.008

.004

.003

.003

U

0.85 

.20

.29 

.41

.18 

.041

'.10

.029 

.012

.005 

.004

Cu

1.27 

.45

.47

.20 

.09

8.01

.15

.08 

.15

2.38 

2.63

2.74

.15

.02

.76

V20s

2.92

.22

2.07 

1.36

.17

<.l

S

Si

XX

XX 

XX

XX 

XX

XX 

XX

XX 

X

-X+ 

XX

XX 

XX

XX 

X

XX 

XX 

XX 

XX

Al

X

X 

X

X

x+

XX

XX 

.X

x+

x+ 

x+

x+

X

x+

XX 

XX 

XX
COPPER AND URANIUM DEPOSITS, COYOTE DISTRICT, N. MEX. 373

........ g

J I

§8 I I

K W

X

+ + I

O fa
374 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

O 

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8.8

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pq 

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percent

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graphici

spectro ive 

quantitat

aCD 

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 a

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§5gfe°6 ;_ *** ^ *§ 

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66

Standard spectro

. .do........ -. ..-.......

do -

do- ... ...

Green coarse-grained arkosic 

sandstone with cbaloocite ... 

Fossiliferous limestone with 

chalcocite'and malachite __

.X

:I+

.X

.OX

.001

.OX+

.ox-

.X

.oxX-

.0005

.OOX+

.ox-

.OOX+ 

.OOX+

.oox-

.0005

.oox- 

.oox- 

.ooox

.ooox

0

.0005

.oox 

.oox 

.oox-

.oox-

.OOOX+

.0005

x' X+

.XX

.x+

.0001

See footnotes at end of table.
376 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

"o w

Si

.S 

.

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+ 

M M

++ \

M M

KX

oooo oo

\ \

M M MM o o oo ft M

OOOO 00

OOO

oooo oo

lit

oooo oo oooo

OOOO OO OOOO

o o o oo oooo

'+ + I . I

M M MM MMMM

8 8 88 8888

I I

MMM 

888

MMM 

888

M M M M MM MMMM 

g S S S SS 8888

 a %a

i 1 Y-I « 

tg ^ rSS 53 2} & S ~

CO CO COC« S « rH C«
26*

14

43

21 «

02

e5

.....do......... ..................

.doGreen coarse-grained arkosic

.OOOX

.ooox

.OOXTr.

.001

0

0

0

0

.05

.OOX

.oox

0

0

.005

0

0

0

0

.001

0

0

0

0

.01

.oox

nnTT

.oox-

.oox

.001

0

0

0

0

i Example of notation, in percent: XX, > 10; O.X+, 0.464 to 1.0; O.X, 0.215 to 

0.464; O.X , 0.100 to 0.215; Tr., near threshold amount.

s Colorimetric analyses by H. E. Crowe, R. R. Beins and C. E. Thompson show 

approximately 150 ppm As, 120 ppm Mo, 50 ppm Se, and 4 ppm Qe. Radiochemieal 

analyses of uranium daughter elements by J. N. Rosholt, Jr., show 1.34 percent Th^o 

ionium), 1.22 percent Paz31 , 1.08 percent Ra!2«, 0.92 percent Rn»", and 0.94 percent

Pb310. The figures 

elements present as

abundance. The da

and that the original 

3 Assay figures are 

4 Locations shown 
378 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

Area F, Arturo Le Deux property. Massive pink medium-grained 

limy micaceous arkosic sandstone contains uranium and vanadium between pits f9 and f!2 (pi. 29). The sandstone ranges in thickness 

from a featheredge to 4 feet and crops out sporadically at the surface. 

This sandstone is about 770 feet above the base of the formation and 

is enclosed in copper-bearing gray shale containing thin seams of black 

shale. Metatyuyamunite is concentrated in micaceous seams at the 

contact of the sandstone and the shale in pit fll and disseminated 

through the sandstone in pit f9. A high-grade ore pocket found 2 

feet below the surface in the f eatheredge of the sandstone in pit fll 

probably extends to the north end of pit f 12. The ore between depths 

of 2 and 4 feet is less than 2 feet thick. The radioactivity is not above 

background count south of pit f 12 and north of pit f8, and no other 

uranium deposits were found in this zone. The analyses in table 7 indicate that uranium has been leached from the uraniferous shale and 

redeposited in the adjacent sandstone. The lack of control by sedimentary structures within the sandstone and the close association with 

copper-bearing shale are exceptional.

Three nearly vertical fluviatile sandstone beds between 1,920 and 

1,960 feet above the base of the Sangre de Cristo formation contain 

uranium or vanadium deposits in the eastern part of area F. The 

middle or main uranium-bearing sandstone is a gray-brown poorly 

sorted, massive limy sandstone about 6 or 8 feet thick. This sandstone 

contains isolated concentrations of uranium in each pit between f!9 

and f26. Pockets of uranium ore occur chiefly in poorly defined lenses 

of coarse, pink, limy sandstone that contains carbonized wood and gray 

or black clay and limestone fragments. The pink color is distinctive 

and becomes more intense as the radioactivity increases. Black micaceous vanadium minerals impregnate the sandstone along bedding 

planes and partly surround the uranium pockets. The black color of 

clay fragments in ore of high vanadium content probably is the result 

of adsorbed vanadium, but at least part of the vanadium is in the clay 

mineral structure. The ore-grade material is less than a foot thick 

except in pits f23 and f26 where metatyuyamunite is abundant.

Several vertical slickensided joints cut the sandstone between pits 

f23 and f26. One joint contains nonradioactive caliche and iron 

oxides. A narrow zone of sandstone adjacent to this joint is barren; 

beyond this a zone impregnated with black vanadium minerals is 

parallel to the joint and partly envelops a small uranium pocket.

The lowest of the three sandstone beds contains small vanadium 

deposits, but the uranium content is low. The highest of the three 

sandstone beds is represented by a group of small isolated hard white 

massive fine-grained limy sandstone lenses at about the same stratigraphic position above the main ore-bearing sandstone. Several of
GEOLOGICAL SURVEY BULLETIN 1030 PLATE 33

A. Polished longitudinal section of carbonized wood (dark gray) replaced 

by blue chalcocite (gray) containing residual grains of pyrite and bornite (not visible). X 50.

B. Polished cross section of carbonized wood (dark gray) replaced by gray chalcocite (gray) and 

minor covellite (not visible). Shows cell structure and growth rings. X 50.

PHOTOMICROGRAPHS OF COPPER ORES, COYOTE DISTRICT, MORA

COUNTY, N. MEX.
GEOLOGICAL SURVEY BULLETIN 1030 PLATE 34

A. Polished section of uraniferous sandstone, Bias Medina property, pit b-4. Quartz and 

feldspar (high relief) and calcite (low relief) replaced by chalcopyrite (cp) and black uraniferous substance (u). X 50.

B. Thin section of hematitic uraniferous sandstone, Bias Medina property, pit b-4. Quartz (</). 

hematite-impregnated feldspar (/), and calcite (c), replaced by chalcopyrite and black uraniferous substance. X 70.

PHOTOMICROGRAPHS OF URANIFEROUS SANDSTONE, COYOTE 

DISTRICT, MORA COUNTY, N. MEX.
COPPER AND URANIUM DEPOSITS, COYOTE DISTRICT, N. MEX. 379

these lenses contain uranium but no copper or vanadium. The part of 

the lenses that contains uranium is pink, as in pit f28, f32, and f33.

An ore-grade layer 3 to 5 inches thick parallels a slickensided bedding plane in the middle of a 3-foot massive limy sandstone bed in 

pits f32 and f33. The layer is apparently continuous between these 

pits and may extend 50 feet farther north. The deep pink ore-grade 

material grades into barren white sandstone.

URANIFEROUS SILTSTONE AND SHALE

A uraniferous micaceous marine siltstone and shale bed overlain by 

a thin bed of f ossilif erous marine limestone in area A is correlated with 

a similar uraniferous rock sequence in area C. If this correlation is 

correct, the basal 330 feet of the Sangre de Cristo formation is missing 

in area C because 670 feet of beds intervene between the uraniferous 

siltstone and the apparent base of the formation in area.A, but only 

340 feet intervene in area C. If the uraniferous siltstone beds are 

correlated, the uraniferous sandstone beds in area F can be correlated 

with those in area C. The discrepancy in thickness of the basal beds 

may be due to nondeposition or, more probably, faulting that has cut 

out the basal part of the formation in area C.

The uraniferous siltstone averages 2 feet in thickness and can be 

traced more than 5,000 feet in area A and 1,500 feet in area B. The 

bed is exposed downdip for 200 feet. Samples from many trenches 

show that the lithologic character and the uranium content are remarkably uniform (see table 3). Nine segments of this bed in area 

A (pi. 25) and one in area C (pi. 27) contain an average of 0.01 percent uranium. Elsewhere the uranium content is about half as much.

The uraniferous beds cannot be traced between areas A and C. 

Near the south end of area A the siltstone grades into radioactive 

sandstone that contains some malachite. In places the siltstone facies 

between areas A and C is replaced by sandstone.

MINERALOGY OF URANIUM DEPOSITS

The chief ore minerals in the uranium deposits in sandstone are 

metatyuyamunite, an unidentified uraniferous substance, black 

micaceous vanadium minerals similar to "roscoelite," chalcopyrite, and 

malachite. Uraninite has not been identified in any of the uranium 

deposits in sandstone. No other uranium and vanadium minerals 

have been recognized in the uraniferous siltstone.

Most of the uranium in area B is apparently in hematite (?) and 

especially in a black uraniferous ferric (?) substance that gives positive tests for uranium, iron, and copper but does not give an X-ray 

diffraction pattern. Not all the black "mineral" contains uranium but 

it is difficult to distinguish between the two varieties visually. In 

oblique light fragments or irregular surfaces of the uraniferous substance appear black, but polished surfaces in a light source perpendicu-
380 CONTRIBUTIONS TO THE GEOLOGY OF TIEANIUM

lar to the surface appear gray. Grains viewed under either oblique 

or vertical light commonly show a red internal reflection. Under the 

microscope the uraniferous substance is seen to be interlocked with 

chalcopyrite, which it apparently replaces (pi. 34). Both minerals 

replace calcite and, to a lesser extent, quartz and altered feldspar. 

Both minerals occur chiefly as finely disseminated grains that clearly 

were formed later than calcite, which was formed later than the sand 

grains. A few detrital grains contain chalcopyrite and a black substance, but the amount of metal so deposited is negligible.

A heavy-mineral concentrate, sample 251, is composed of chalcopyrite (50 percent), the unidentified substance (30 percent), and small 

amounts of quartz, feldspar, tourmaline, and accessory minerals. This 

sample was submitted for semiquantitative spectrographic analyses 

after crusher steel was removed (table 11). The unidentified uraniferous substance is probably a metamict or amorphous ferric oxide. 

Calculations from semiquantitative spectrographic data indicate that 

the uranium content of the uraniferous ferric oxide is less than 3 

percent. It is suggested that the difference in physical properties between the black uraniferous ferric substance and the hematite may be 

the result of changes caused by radiation from a much greater 

uranium content.

Most of the sedimentary rocks of the Sangre de Cristo formation are 

feldspathic. The composition, in percent, of the ore-bearing sandstone is quartz (30-40), feldspar (30-40), calcite (20-30), muscovite 

(0-5), rock fragments (0-20), and a little hematite and nontronite. 

The feldspar is chiefly oligoclase and microcline. Although potash 

feldspar was not detected in the five samples studied by X-ray diffraction techniques, much of the feldspar shows the characteristic gridiron 

pattern of microcline, and orthoclase may be present.

Except in the upper uraniferous sandstone in area F, the calcite content of the radioactive sandstone generally is higher than the content 

of nonradioactive sandstone. Calcite replaces altered feldspar and 

quartz; it also fills fractures in these minerals. Where replacement is 

advanced, the detrital grains are represented by corroded remnants 

that are no longer in contact. Some of the calcite in area F is high in 

manganese. The genetic significance of these facts is discussed on 

page 388.

The pink color of some uraniferous sandstone ore is caused by 

"dusty" grains of hematite (?) which coat quartz grains and impregnate altered feldspar grains and foreign rock fragments. Most of the 

"dusty" hematite (?) tested gives a positive test for uranium.

CHEMICAL CHARACTERISTICS OF URANIUM-BEARING SANDSTONE

The amount and relative proportions of uranium, vanadium, copper, and certain minor constituents vary greatly, as shown by the 

selected analytical data in tables 11 and 12.
COPPER AND URANIUM DEPOSITS, COYOTE DISTRICT, N. MEX. 381

In general, the uraniferous sandstone of the Coyote district has a 

higher content of copper, lead, rare earths, and other minor constituents than the uranium ores in the Morrison and Shinarump formations of the Colorado Plateau. Lead and the rare earths are concentrated with uranium in the radioactive sandstone and in the heavymineral fraction (sample 251, table 11). The highest rare-earth content is found in the limonitic sandstone core of a carbonized log, 

sample 89. The rare-earth content of this sample exceeds the uranium 

and vanadium content. The few selenium analyses (tables 7 and 12) 

suggest that the selenium content is higher in the uraniferous rocks, 

particularly in the most uraniferous sandstone, but the data are not 

conclusive.

TABLE 12. Chemical characteristics of uranium-bearing sandstone

{Radioactivity analyses by S. P. Furman, chemical analyses by C. E. Thompson, D. L. StockwelL E. C. 

Mallory, J. F. Wahlberg, Wayne Mountjoy, J. P. Schuch, W. D. Goss, J. H. McCarthy, H. E. Bivens, 

R. F. Dufour, and J. L. Siverly]

Tield 

no.

Pit 

no.

Lithologic description

Percent

eU U Cu V20»

Se 

(ppm)

Ratios

eU/U V/eU

Uranium "ore"

261

351 

350

332

b4

f33

m

b3

pink, limy arkosic sandstone. May

uraniferous iron oxide(?).

0.11

.044 

.038

.022

0.10

.036 

.033

.017

0.01

.02 

.02

.02

<0.1 

<.l

<.l

3

1.10

1.22 

1.15

1.30

<1.27 

<1.45

<2.54

M4

Uranium-copper "ore"

360 » 

352

. iftK

353

187 249"

248

247J

334 

333

-i*

near 

b4 

bl

. ,fll

fl2

f!2

blO

blO

blO

b7 

b4

to

Coarse massive pink sandstone, chalcopyrite. 

Do.

Do.

Do.

Do.

Limy arkosic sandstone.

0.78 

.26

.18

.068

.063

.061

fl^S

.051

.048 

.043

0.41

9Q

.20

.019

.042

(\AI

.049

.036

.024 

.033

<0.46 

.47

1.27

.89

1.22

1.37

.79

1.66 

.62

<0.2 

.22

.15 

.12

50

9

1.90 

.76

.90

3.58

1.50

1.49

1.14

1.42

2.00 

1.30

<a»

.47

1.74 

1.56

Uranium-vanadium "ore"

355

349

345

346

344

' 343

fll

Q6,

S3

126

fii?

Metatyuyamunite in micaceous sandstone.

0.81

.20

(V7K

.046

.042

.015

0.85

142

.038

n<n

.027

.006

0

9!!

.17

.09

.10

.02

2.92

2.07

1.22

1.36

.90

.29

50 0.95

 1.10

1..97

1.10

2.55

2.50

2.0

5.66

8.97

10.95

11.95

10.8

1 Colorimetric analyses by H. E. Crowe, R. R. Beins, and C. E. Thompson show approximately 150 ppm 

As, 120 ppm Mo, and 4 ppm Ge.

The eU/U ratio (table 12) may give an indication of the amount of 

uranium that has been leached from the sample. The thorium content 

of these rocks is below O.OX, the spectrographic threshold, and can 

be ignored because the radioactivity of thorium is only about onefifth that of the same amount of uranium. Where uranium is in
382 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

equilibrium with its daughter products, the ratio is 1.0. If selective 

leaching or precipitation of daughter products can be ignored, ratios 

much greater than 1.0 indicate recent leaching of uranium and ratios 

less than 1.0 indicate that uranium has been reprecipitated recently. 

This interpretation is less hazardous where the uranium content is 

appreciable (more than 0.05 percent), where the ratio is greater than 

2.0, and where there is corroborating field evidence.

The eU/U ratios (table 12) and the field evidence indicate that 

some leaching and redeposition of uranium occurs locally. The eU/U 

ratio changes from 2.0 to 4.0 in siltstone and shale, and apparently 

uranium is leached from the uraniferous shale and redeposited in 

adjacent sandstone in some areas.

GEOCHEMICAL, PROSPECTING

Geochemical prospecting techniques were used in the hope that 

deposits hidden under alluvium might be detected. A total of 457 

botanical and 339 soil samples were collected. Wherever possible, soil 

and botanical samples were collected from the same place to determine 

which prospecting method was more satisfactory; the botanical 

samples were obtained from plant foliage to insure approximate 

uniformity of metal content and age of growth.

In general, the results were disappointing and neither geochemical 

nor botanical testing appears to be well suited to detecting small 

deposits of this type. A poor correlation between plant and soil data 

was obtained. This may be partly the result of the extraction of 

metals from the soil by plant roots. Several trenches dug beneath 

trees having a high copper or uranium content failed to disclose copper 

minerals or radioactivity in the bedrock. In area I, plant and soil 

data gave an entirely different pattern even though only the needles 

of ponderosa pine were sampled. The anomalies in content of copper 

in ponderosa pine outlined most of the copper deposits but neither the 

lead and zinc anomalies for ponderosa pine nor the anomalies for any 

of the three metals in soil samples were related to the ore bodies.

The reasons for the failure are: (1) prevalent surface wash, 

(2) different metal content of each rock type, and (3) the small size 

of rock units and ore bodies which caused the root circle of plants to 

overlap several beds of different metal content. Samples of the foliage 

of ponderosa pine, piny on, juniper, and scrub oak were collected. The 

metal content varied greatly but was higher in the pines than in the 

other trees.

The soil and ashed plant samples were analyzed for copper, lead, 

and zinc by rapid colorimetric methods. All three metals were determined in plant samples but only lead and zinc were determined in 255 

soil samples. Uranium was determined by the fluorimetric method in 

159 representative botanical samples.
COPPER AND URANIUM DEPOSITS, COYOTE DISTRICT, N. MEX. 383

ORIGIN

In this section is postulated a tentative theory of origin of the 

mineral deposits that is consistent with the mineralogical, chemical, 

and field relationships. Such a theory is of necessity speculative; 

whether the ores were formed by the processes postulated remains to 

be demonstrated and depends on the correctness of assumptions that 

appear reasonable in the light of current physico-chemical knowledge 

but cannot be proved. The senior writer is primarily responsible for 

the ideas expressed in this section.

Briefly, the metals now concentrated in the mineral deposits are 

considered to have been derived from the Precambrian terrane and 

to have been concentrated by syngenetic sedimentary processes and, in 

the case of the uranium deposits in sandstone, reconcentrated by warm 

chemically active ground water with a possible juvenile component. 

Copper and uranium were partly separated because they were 

deposited in different chemical environments by different mechanisms. 

Copper was deposited as a sulfide by H2S, but uranium probably was 

adsorbed on a ferric hydroxide precipitate. The origin of each type 

of deposit is discussed separately in detail below and a summary is 

given at the end of the section.

COPPER DEPOSITS

The copper and associated uranium in the copper-bearing shale 

probably, were derived chiefly from Precambrian rocks. Many small 

copper deposits of pre-Pennsylvanian age are found in the Precambrian rocks of northern New Mexico. The metal probably was 

derived partly from these deposits but chiefly from acidic igneous 

rocks, which contain an average of 16 grams of copper per metric 

ton (0.0016 percent), according to Rankama and Sahama (1950, p. 

697).

The carbonaceous copper deposits are local stagnant basin shale 

facies characterized by abundant carbonized plant remains and ferrous 

iron. The enclosing barren red rocks are colored by ferric oxides; 

they do not contain carbonaceous material, although plant imprints 

remain. The highest content of copper and uranium in the shale is 

found in shale with the most carbonaceous material. Copper probably was deposited in local swamps, lagoons, or lakes in an oxygendeficient environment which favored the carbonization of plant material and reduced iron to the ferrous state.

Copper, iron, and a little uranium from the Precambrian terrane 

probably were transported in solution by surface or ground waters 

to local anaerobic basins where copper and iron were precipitated as 

sulfides by hydrogen sulfide generated by the decay of organic material or the reduction of sulfates by anaerobic bacteria. A small 

part of the uranium was precipitated as uraninite. A little was
384 CONTRIBUTIONS TO THE GEOLOGY OP URANIUM

probably adsorbed on carbon, ferric hydroxide, or humic compounds, 

but much of the uranium may have remained in solution or suspension 

to be deposited elsewhere.

The metal content and the form in which the metals were transported in solution are unknown but the metal content need not have 

been high if the process was long continued.

Microscopic study shows that carbonized wood was replaced first by 

pyrite and then by copper sulfides in the following order: chalcopyrite, bornite, chalcocite, blue chalcocite with excess CuS, and 

covellite. Only pyrite and chalcocite are important quantitatively. 

The proportion of copper progressively increases and the proportion 

of iron and sulfur progressively decreases in each succeeding member 

of the series with the exception of sulfur in covellite. The amount 

of sulfide ion in solution seems to have been the critical factor determining the mineral content. The concentration of iron in solution 

was probably always greater than the concentration of copper because 

of its greater abundance in rocks and because it would be regenerated 

as iron-bearing sulfides were replaced by copper-bearing sulfides. 

Sulfide ion would be generated continuously by decay of organic 

matter or by reduction of sulfates by anaerobic bacteria, but the 

sulfide ion content of the solution fell as deposition of sulfides continued if the sulfur content of the minerals formed at each stage 

is a fair indication of the sulfide ion content of the solution. The 

solubility of iron sulfide is less than the solubility of copper sulfide, 

therefore pyrite began to precipitate first. Once the solubility 

product of copper sulfide was reached, however, mixed copper-iron 

sulfides began to precipitate and, as the sulfide ion concentration fell, 

sulfides progressively richer in copper were precipitated as a result 

of the greater affinity of copper for sulfide ion in acid aqueous solution. The mineralization process would be terminated by the exhaustion of sulfide or copper ion in solution or by changes in pH or 

oxidation potential. The very low uranium content (less than 0.01 

percent) of the black copper-bearing shale beds can be explained 

partly by the low concentration and relatively high solubility of 

uranium in acid swamp water (pH 4.0-4.5) and partly by precipitation of iron as a sulfide rather than as a flocculent hydroxide that

could adsorb uranium. The near-absence of pitchblende, which might

be expected to form in this environment, probably indicates that the 

solubility product was seldom exceeded because the oxidation potential 

was low enough. It must be tentatively concluded that the uranium 

and iron remained in solution or colloidal suspension in t tie excurrent 

waters to be deposited elsewhere. The writers are aware that many 

factors are ignored in the foregoing analysis.

The deposition of copper probably began with the establishment of 

anaerobic conditions, but it may have continued after t tie enclosing
COPPER AND URANIUM DEPOSITS, COYOTE DISTRICT, N. MEX. 385

sediments were buried and during the period of diagenetic changes. 

Many chalcocite nodules have a concretionlike structure that indicates slow, gradual growth. Isolated masses of chalcocite occur in the 

cores of some limestone nodules. In strict terminology, these deposits 

are not syngenetic but rather semisyngenetic or penecontemporaneous 

with sedimentation and diagenetic processes. The presence of sulfide 

concretions, the association of copper with rocks deposited in an environment of putrefaction (Fdulnis] regardless of type, and the absence of copper in these same rock types deposited under other conditions strongly support a penecontemporaneous origin for the copper 

deposits. An alternate and, to the writers, less likely hypothesis 

would have the metals extracted from ground waters by adsorption 

or reduction after burial of the enclosing rocks. A third, and untenable, hypothesis would have the copper deposits formed by the 

accumulation of detrital grains of copper minerals derived from preexisting deposits. The association of copper with carbonaceous sedimentary rocks deposited in foul water is unmistakable whatever the 

origin of the deposits.

URANIUM DEPOSITS

Uranium and vanadium in addition to copper were probably derived from Precambrian rocks, but unlike the copper deposits the deposits of uranium and vanadium are, in part, epigenetic.

Precambrian pegmatite and (or) quartz veins contain uraniumbearing minerals in the Petaca, Ojo Caliente, Elk Mountain, Rociada, 

and Gallinas Canyon districts. The uranium-bearing minerals include uraninite, gummite, uranophane, samarskite, betafite, fergusonite, euxenite(?), and hatchettolite (Jahns, 1946, p. 61-68, 267, 277). 

These minerals contain niobium, tantalum, thorium, lithium, beryllium, or bismuth. The nearest of these districts, the Rociada district, 

is about 15 miles south of the Coyote district. Several radioactive 

anomalies have been detected in Precambrian and Pennsylvanian rocks 

by radioactivity surveys along the west side of the Coyote district. 

Part of the uranium came from the pegmatite but most of the uranium 

probably was derived from granitic rocks. Studies of the arkose derived from granite in the Powder River Basin of Wyoming show that 

possibly as much as two-thirds of the uranium in granitic rocks is 

present in disordered intergranular phases or is loosely held on the 

surface of mineral grains and can be released by mechanical disintegration without much chemical weathering (Harold Masursky, oral 

communication). Rankama and Sahama (1950, p. 634) report 3.963 

grams of uranium per metric ton in granitic rocks and the wide distribution of radioactive anomalies in the granite and simple granite 

pegmatite of the Precambrian areas near Guadalupita suggests that 

this average figure may be too low for this granite. Investigators 

report the average vanadium content of igneous rocks to be 150 and
386 CONTRIBUTIONS TO THE GEOLOGY OF UBANIUM

315 grams of vanadium per metric ton (Eankama and Sahama, 1950, 

p. 596). The vanadium content of granite is much lower; investigators report between 1 and 30 grams per metric ton for granite or 

acidic igneous rocks (Rankama and Sahama, 1950, p. 596). The 

vanadium content is highest in gabbro and dolerite and part of the 

vanadium may have been derived from these rocks in the Precambrian 

terrane rather than for granite. Erosion of the source areas furnished 

enough uranium and vanadium to account for the amount concentrated in the deposits if an efficient process of concentration were 

available.

The uranium content of natural waters is very low except in the 

vicinity of uranium mines or districts where it may be from several 

hundred to several thousand parts per billion (109 ). The uranium 

content of natural waters is very sensitive to changes in pH. On the 

basis of present information, waters with a pH of 6.5 do not contain 

more than 1 to 6 parts per billion (Philip Fix, oral communication, 

1954) but waters with a pH of 5.5 may contain several hundred parts 

per billion although the average in areas of uraniferous rocks probably is on the order of 10. The uranium content of waters derived 

from the Precambrian terrane must have between the extreme limits 

of 1 and 100 parts per billion. A sample of domestic water from a 

well in the Guadalupita district contained 15 parts per billion and 

this figure does not seem unreasonable for natural waters from which 

the uraniferous shale beds were deposited. Considering the widespread occurrence of uraniferous rocks and sulfide deposits in the 

source areas, the waters in restricted drainages may have had a 

uranium content as high as 50 parts per billion and a pH as low as 

4.0 for short periods of time where oxidizing sulfide deposits lowered 

the pH. A large flow from an old tunnel draining the several square 

miles of a gold district has 80 parts per billion uranium and a pH of 

2.5 (Philip Fix, oral communication, 1954). Using a figure of 10 parts 

per billion, the syngenetic uranium deposits in shale or siltstone represent a concentration ratio of 10,000 to 20,000 and the epigenetic deposits in sandstone represent a ratio higher than 100,000. Such high~ 

concentration ratios require efficient mechanisms of concentration operative in extremely dilute solutions. The adsorption mechanism 

postulated in this paper is believed adequate, although the adsorption 

of ferric hydroxide has not been fully tested. The scavenging power 

of activated charcoal and other compounds used in the laboratory to 

remove traces of deleterious ions from water shows the ability of some 

adsorptive compounds to remove metallic ions from extremely dilute 

solutions.

Uraniferous siltstone. These deposits, though generally similar to 

the copper-bearing shale, differ from it in several ways. The uraniferous siltstone has a higher uranium (0.01 to 0.02 percent) and
COPPER AND URANIUM DEPOSITS, COYOTE DISTRICT, N. MEX. 387

iron content and a much lower content of copper and carbonaceous 

matter than the black shale. The vanadium content is generally less 

than a few hundredths percent, only slightly higher than that of the 

copper-bearing shale. Copper is present as malachite, but sulfides or 

uranium minerals have not been found. Some uranium may be in 

detrital minerals containing rare earths, but most of it is probably 

adsorbed on iron oxides or on clay, mica, and carbonaceous material.

There is no reason to doubt a syngenetic or penecontemporaneous 

origin for the uraniferous siltstone. The uranium-bearing beds are 

persistent and the uranium content is relatively uniform. The differences in metal content between the uraniferous siltstone and the 

copper-bearing shale probably reflect differences in the conditions of 

deposition.

The hypothesis outlined in the following paragraph is suggested 

to explain the observed separation of uranium and copper and to 

indicate a direction for further research.

The uraniferous siltstone probably was deposited in a lagoon which 

had limited access to the sea. Anaerobic conditions were much less 

extreme than in the black shale and consequently the lagoonal water 

was more nearly normal. Both the pH and the oxidation potential 

were probably higher than in the stagnant-water environment in 

which the black shale was deposited. The absence of sulfide minerals, 

the lower copper content, and the higher uranium content of the siltstone probably are all indirect consequences of the low content of 

carbonaceous matter and hence the near absence of hydrogen sulfide. 

Under these conditions an effective mechanism for the precipitation 

of copper did not exist and the iron probably was precipitated as 

ferric hydroxide which readily adsorbs uranium rather than as a 

sulfide which does not. Uranium and copper minerals probably could 

not precipitate from the dilute near-neutral or slightly acid, mildly 

oxidizing waters and uranium was probably adsorbed on or coprecipitated with iron compounds such as ferric hydroxide that later dehydrated to form limonite. The precipitation of iron hydroxide and 

uranium was probably initiated by the mixing of excurrent water 

from the swampy flood plain and the stagnant-water basins in which 

the copper was deposited with the marine water of the lagoon. 

Colloids tend to be flocculated by sea water and recent data indicate 

that uranium is effectively removed from an acid, iron-rich solution 

(pH 2.9) from which ferric hydroxide is precipitating when the solution is neutralized (pH 6.0). The acidity of swamp water (pH 

4r-4.5) would be neutralized by mixing with sea water (pH 8.1-9.6) 

and the uranium would be adsorbed on colloidal ferric hydroxide 

coagulated by sea water. If the sedimentation rate in the lagoon was 

low, a considerable concentration of uranium might occur over a 

long period of time.
388 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

Uranium-vanadium deposits in sandstone. The uranium-vanadium deposits in sandstone differ in several important respects from 

the copper deposits and the uranif erous siltstone, notably in the much 

higher uranium and vanadium contents. The metals, like those in 

the other deposits, are believed to have been derived from Precambrian rocks, but these deposits are epigenetic and probably formed 

long after the sandstone was deposited. A two-stage epigenetic origin 

is postulated.

Three processes by which the deposits could have formed are: (1) 

extraction and reconcentration from earlier low-grade syngenetic deposits by ground waters or hydrothermal solutions, (2) direct derivation from previous deposits or igneous rocks in the Precambrian 

source areas, or (3) addition of uranium and vanadium from a 

magnetic source. None of these possibilities can be disproved but the 

first is most probable and the last is unlikely.

The absence of uranium, vanadium, and copper along the major 

faults and the lack of a known magmatic source for these metals argue 

against a simple hydrothermal origin; however, hydrothermal solutions probably were active in the district as shown by the sericitization 

of sheared arkose and the replacement of detrital quartz and feldspar 

by calcite and hematite. No indication of the source of the hydrothermal solutions has been found; they may have been derived from 

the basalt plugs east of the district or from an unknown body at 

depth. A relationship cannot be demonstrated between sericitized 

ground and uranium deposits and the role of a hydrothermal component in the formation of the deposits can be questioned if the less 

clear-cut alteration changes described in the following paragraphs can 

be explained in another way.

Normal surface or ground water probably could not cause the 

replacement of quartz and feldspar by calcite. If calcite were introduced by a normal cementation process the sand grains should be 

nearly in contact, but the grains are corroded and isolated where 

replacement is advanced. The high manganese content of some calcite 

and the extensive replacement of quartz and feldspar in most uranium 

deposits seem to require the introduction of some calcite by chemically 

active fluids, perhaps at a higher temperature than normal for ground 

water. If this conclusion is correct it is reasonable to ascribe the 

calcitization to an early effect of the solution responsible for the 

deposition of iron and uranium.

A direct relationship between the degree of hematitic alteration 

and the uranium is shown by the field and laboratory evidence. Hematite, nontronite, and the uraniferous ferric oxide are considered 

products of warm, chemically active ground water with a possible 

juvenile component. The presence of fresh feldspar and chalcopyrite 

on the outcrops suggests that the hematitic alteration is not related
COPPER AND URANIUM DEPOSITS, COYOTE DISTRICT, N. MEX. 389

to surface oxidation. The iron in nontronite, a montmorillonite-type 

clay with ferric iron, cannot be added without destroying the structure 

of the clay mineral, for example, by the adsorption of iron on a 

montmorillonite clay in normal ground water. The iron must have 

been introduced at the time nontronite was formed and the formation 

of nontronite, except by the weathering of ferromagnesian minerals, 

probably requires a high ferric iron concentration and temperatures 

higher than those of normal ground waters.

To explain the field and laboratory evidence the writers tentatively 

postulate a two-stage epigenetic theory of origin: that the uranium 

deposits in sandstone are epigenetic and were leached and redeposited 

from earlier syngenetic uranium deposits containing from 0.005 to 

0.03 percent uranium. The evidence is not conclusive and the 

hypothesis is necessarily speculative.

Barren chemically active hydrothermal (?) solutions are believed 

to have migrated along the Laramide (?) faults and through permeable beds. The warm, active acid solutions sericitized the arkoses 

near the channels and leached iron, uranium, vanadium, and calcium 

from the low-grade uraniferous rocks through which they moved. 

Much of the uranium in the shale probably was loosely held by adsorption and hence was readily removed from the shale adjacent to 

the faults. The ability of such hydrothermal solutions to sericitize the 

rocks and to leach iron and uranium is shown by Phair's study (1952) 

of the altered radioactive quartz bostonite in the Front Range of 

Colorado. Phair found that an appreciable part of the uranium and 

iron were leached from the altered quartz bostonite dikes near the 

pitchblende deposits.

The acid solutions spread out in permeable sandstone beds and 

merged with the ground-water system whose circulation may have 

been reactivated by folding. The ground water with its juvenile(?) 

component flushed the sandstone and picked up more metal. The 

movement of the ground water was controlled by the permeability, 

porosity, and structure of the aquifers. In favorable sedimentary 

structures, uranium-vanadium and iron were deposited by change in 

pH, oxidation potential, complex-ion destruction, or flocculation of a 

colloidal suspension by dilution or mixing of solutions of different 

characteristics. It is suggested that uranium compounds could not 

form under the existing conditions and the uranium and rare earths 

were adsorbed on or coprecipitated with ferric hydroxide formed when 

the originally acid solution was neutralized by dilution or by reaction 

with calcite. The ferric hydroxide might have remained in suspension 

and continued to move with the ground waters until flocculated by 

some mechanism, such as mixing with waters containing dissolved salts 

or strained out by decrease in pore size of the sandstone. The flocculent precipitate may have continued to adsorb uranium from mi-
390 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

grating ground waters until the unbalanced charges were fully 

neutralized. Precipitation of ferric hydroxide begins at a pH of 

3.0-3.5 and virtually all the uranium will be removed from an ironrich solution by the time a pH of 6 is reached. The marked concentration of rare earth in uraniferous iron oxides (samples 251 and 89, 

table 11) might also be explained by adsorption or coprecipitation on 

ferric hydroxide because their behavior is generally similar to the 

behavior of uranium. Vanadium, where present, seems to be in the 

clay minerals or adsorbed on carbonized wood. Probably most of the 

vanadium is in a vanadium hydromica formed by incorporation of 

vanadium in the structure during the recrystallization of an existing 

clay mineral. The proportions of uranium, vanadium, and copper 

were controlled by the characteristics of the sediments and the density, 

temperature, pH, oxidation potential, and metal content of the 

solution.

The principal evidence against a syngenetic origin for the uraniumvanadium deposits in sandstone is the difficulty in explaining the 

sericitization of sheared arkose, the extensive replacement of quartz 

and feldspar by calcite and hematite, and the presence of both early 

sulfides containing ferrous iron and late ferric iron oxides containing 

uranium and rare earths. The uranium content of the uraniferous 

siltstone probably represents the maximum that can be expected in 

syngenetic deposits formed under conditions that existed in the 

Coyote district, unless the uranium content of the water was abnormally high at certain times. An abnormally high uranium content in 

water can be expected only where the water is acid and waters more 

acid than those that deposited the black shale (pH 4.0-4.5) could 

hardly be expected in a terrane containing limestone. The uranium 

content of the black shale and uraniferous siltstone is low as comared to that of the sandstone deposits but the total amount is much 

greater. The uranium content of a syngenetic uranium deposit is 

limited by the sedimentation rate and by the suggestion that uranium 

is readily removed by absorption in slightly acid or neutral waters and 

hence is dispersed. The uranium content of the syngenetic deposits 

in the Coyote district is comparable to that of most other syngenetic 

deposits except for a few deposits like the presumably syngenetic 

Swedish kolm (ash-rich coal(?)) that have a much higher organic 

content.

Given a sufficient volume of solution and an efficient mechanism of 

concentration, uranium deposits might be formed from very dilute 

solutions, even from the ground waters existing in the district today. 

A water sample from a well in the central part of the district contained 

0.015 parts per million uranium (Zeller and Baltz, 1954, p. 11). Several high uranium concentrations in ponderosa pine in area E were not 

paralleled by anomalies in the bedrock and the uranium probably
COPPER AND URANIUM DEPOSITS, COYOTE DISTRICT, N. MEX. 391

was extracted from dilute ground water percolating through the 

sheared ground.

Although a few clastic grains containing chalcopyrite and a black 

substance have been seen in the uranium ore, microscopic examination 

reveals that virtually all the uranium is later than the calcite cement. 

The absence of niobium, tantalum, thorium, and other elements derived from the uranium-bearing pegmatite and the scarcity of the 

resistant minerals of these elements proves that the amount of uranium, vanadium, and rare earths contributed by the heavy minerals is 

negligible and indicates that most of the uranium was not-derived 

from the pegmatite.

SUMMARY

Copper and smaller amounts of uranium and vanadium freed by 

erosion of the Precambrian terrane were transported to the basins of 

depositions in solution. The metals were removed from solution by 

different mechanisms operating under different conditions and this 

caused a partial separation of metals. The copper and part of the 

iron in solution were precipitated as sulfide in local anaerobic basins 

where carbonaceous shale was accumulating but most of the uranium 

and some iron remained in the still-acid excurrent water, either in solution or suspension until the pH approached 6 by dilution in lakes or 

lagoons or by reaction with limy sediments. A large part of the uranium probably was dispersed upon neutralization by absorption in 

clays but a considerable concentration of uranium occurred where the 

still-acid excurrent waters mingled with sea water in a marine lagoon 

where the sedimentation rate was slow. Here colloidal suspensions 

of ferric hydroxide would be coagulated and the remaining iron 

would be precipitated as ferric hydroxide. The uranium forced out 

of solution by increase in pH upon dilution would be absorbed on or 

coprecipitated with the iron hydroxide, which later dehydrated to 

form hematite or limonite.

Following Laramide( ?) orogeny warm acid ground waters with a 

chemically active (hydrothermal?) component migrating through 

sheared ground and along faults leached lime, iron, uranium, vanadium, and rare earths from the uraniferous sedimentary rocks and 

mingled with the ground waters in the sandstone aquifers. The 

waters were neutralized by dilution by reaction with the calcite cement 

of the sandstone, and uranium and rare earths were adsorbed on 

ferric hydroxide precipitated in favorable sedimentary structures.

COMPARISON WITH OTHER COPPER-URANIUM DEPOSITS

Copper-uranium deposits similar to the deposits in the Coyote district have been found in arkosic red beds, at least partly equivalent 

to the Sangre de Cristo formation, in several areas marginal to the 

ancestral Eocky Mountains.
392 CONTRIBUTIONS TO THE GEOLOGY OP URANIUM

The Cutler formation contains small copper-uranium deposits in 

the Big Indian Wash district and the Lockhart Canyon-Indian Creek 

area of Utah (G. P. Dix, written communication, 1953). The Abo formation, equivalent in part to both the Cutler formation and the Sangre 

de Cristo formation, contains copper deposits in the Scholle, Zuni 

Mountain, and Jemez Springs districts of New Mexico. Uranium 

has been reported from the Scholle and Jemez Springs district. Small 

copper-uranium deposits have been found in the Maroon formation, 

a partial equivalent of the Sangre de Cristo formation in the Huerfano 

Park and La Veta Pass areas, Huerfano and Costilla Counties, Colo. 

The Garo property, Park County, Colo. (Gott, written communication, 1951), has produced a small tonnage of uranium ore from sandstone in the Maroon (?) formation. The Cutler, Abo, Sangre de Cristo 

and Maroon formations form a continuous arkosic red bed unit. The 

deposits in the Lockhart Canyon-Indian Creek area of Utah and the 

deposits in the Maroon formation of Colorado resemble the sandstone 

deposits in the Coyote district. The deposits near Garo and La Veta, 

Colo., and in the Coyote district have a similar structural setting 

along the flanks of the Sangre de Cristo Mountain system.

The occurrence of similar deposits in arkose deposits on the flanks 

of areas of Pennsylvanian uplift in widely separated areas suggests 

that other similar deposits exist. The similarities to the deposits 

of the Coyote district further suggest that ore guides at Guadalupita 

may be applicable to prospecting in other areas.

Copper deposits of the red-bed type, some of which contain small 

amounts of uranium, are present in the Poleo or Aqua Zarca sandstone lentils of the Chinle formation of Triassic age in the Cuba, 

Abiquiu, Cobre Basin, Copper City, and Gallinas districts, all of 

which surround the Nacimiento uplift in New Mexico. Uranium has 

been reported from the Chinle formation near Coyote north of the 

Nacimiento uplift and near Sabinosa along the Canadian River east 

of Las Vegas, N. Mex. These deposits are similar to those described 

in this report. Uranium deposits might be found in sandstone which 

does not contain appreciable quantities of copper in other red-bed 

copper districts.

GUIDES TO ORE DEPOSITS

The ore guides described below pertain to the Coyote district but 

they may have a wider application as indicated in the preceding 

section.

In prospecting for copper deposits special attention should be directed to parts of the Sangre de Cristo formation that contain abundant limestone or gray shale beds, because the ore-bearing black shale 

lenses are enclosed in gray shale and may grade into limestone.
COPPER^ AICB UBANIUM DEPOSITS, COTOTE BJSTKECT, N. HEX. 393

The uranium deposits are in one or more brown or gray fluvial 

sandstone beds near the middle of the Sangre de Cristo formation. 

The outcrops are inconspicuous and a radiation counter is necessary 

for prospecting. Chalcopyrite, malachite, or black vanadium minerals 

and the distinctive pink color of the sandstone are the best ore guides 

but are easily overlooked. The most favorable places in sandstone 

are cut-and-fill structures, especially where the sandstone is coarse 

and contains abundant gray or black clay and foreign rock fragments, 

and carbonized wood. The red (or maroon) sediments probably can 

be ignored because evidence of mineralization has not been found in 

them.

CONCLUSIONS

The uranium content of the copper deposits and the uraniferous 

siltstone is too low to permit the recovery of uranium under presentday conditions. The uranium deposits in sandstone are small, but 

some production might be expected under favorable conditions. Further exploration probably will result in an increase of uranium 

reserves but no large deposits are expected. Geochemical prospecting 

methods are not suitable because of the steep dip of the beds and 

small size of the mineral deposits.

A large part of the value of the present investigation, in the opinion 

of the writers, lies in the genetic implications and practical application 

of the relationships discovered between copper deposits and the 

uranium-vanadium deposits. Some of the more important relationships, chosen for their possible application to the search for uranium 

deposits in other areas, are:

(1) The largest copper deposits are in local black carbonaceous 

shale lenses and contain a negligible amount of uranium.

(2) The only commercial-grade uranium deposits are low in 

copper. They occur in several gray or brown fluvial sandstone beds 

and are localized by small sedimentary structures similar to those in 

the Morrison and Shinarump formations. It is suggested that 

uranium deposits may be found in fluvial sandstone in other "redbed" copper districts but that the conditions favorable for the formation of commercial-grade uranium deposits are not the same as those 

favorable for red-bed copper deposits.

(3) The copper-bearing shale and the uraniferous siltstone are 

essentially syngenetic but the uranium-vanadium deposits in sandstone 

probably are much younger and may have formed from low-grade 

syngenetic deposits by ground water having a hydrothermal (?) 

component following Laramide (?) orogeny. If this theory of origin 

is correct, the search for uranium deposits in arkosic red-bed units 

should be directed to areas where favorable sandstone beds are folded
394 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

or faulted, particularly where they surround younger intrusives. It is 

suggested that undiscovered uranium deposits may exist along the 

flanks of the present mountains where limy sandstone beds in sedimentary rocks of the Cutler, Abo, Sangre de Cristo, and Maroon 

formations or formations of similar lithology are exposed.

(4) It is suggested that the coprecipitation with or adsorption 

on ferric hydroxide offers a mechanism by which uranium deposits 

can form even where uranium compounds (minerals) cannot form. 

This process is operative in acid oxidizing solutions between a pH of 

3 and 6 and applies equally to syngenetic and epigenetic deposits. It 

is suggested that the ferric hydroxide is usually precipitated by 

reaction with calcite. The same adsorption process is believed to 

cause the concentration of the rare earths. The uranium in both the 

siltstone and the sandstone probably was concentrated by this mechanism. If the foregoing is true, the search for large low-grade uranium 

deposits need not be limited to sedimentary rocks rich in organic 

material but should be extended to certain fine-grained sedimentary 

rocks containing iron oxides formed in the manner described.

(5) The distinct pink color imparted by hematite introduced with 

uranium is the best ore guide to the sandstone deposits. The difference 

between it and the red, chocolate, or maroon color of the barren red 

beds is slight but distinctive.

LITERATURE CITED

Bachman, G. O., 1953, Geology of a part of northwestern Mora County, N. Mex.:

U. S. Geol. Survey, Oil and Gas Inv. Map, OM137. 

Brill, K. G., Jr., 1952, Stratigraphy in the Permo-Pennsylvanian Zeugogeosyncline

of Colorado and Northern New Mexico: Geol. Soc. America Bull., v. 63,

p. 809-880. 

Edwards, A. B., 1947, Textures of the ore minerals and their significance:

Australasian Inst. Min. Metallurgy, Melbourne, 185 p. 

Gott, G. B., and Erickson, R. L., 1952, Reconnaissance of uranium and copper

deposits in parts of New Mexico, Colorado, Utah, Idaho and Wyoming:

U. S. Geol. Survey Circ. 219. 

Harley, G. T., 1940, The geology and ore deposits of northeastern New Mexico:

New Mexico Bur. Mines Bull. 15,104 p. 

Jahns, R. H., 1946, Mica deposits of the Petaca district, Rio Arriba County, N.

Mex.: New Mexico Bur. Mines Bull. 25,294 p. 

Lasky, S. G., and Wooton, T. P., 1933, The metal resources of New Mexico and

their economic features: New Mexico Bur. Mines Bull. 7,178 p. 

Lindgren, Waldemar, Graton, L. C., and Gordon, C. H., 1910, Ore deposits of

New Mexico: U. S. Geol. Survey Prof. Paper 68, 361 p. 

Northrup, S. A., Sullwold, H. H., Jr., MacAlpin, A. J., and Rogers, C. P., Jr.,

1946, Geologic maps of a part of the Las Vegas basin and of the foothills of

the Sangre de Cristo Mountains, San Miguel and Mora Counties, N. Mex,:

U. S. Geol. Survey, Oil and Gas Inv. Prelim. Map 54.
COPPER AND URANIUM DEPOSITS, COYOTE DISTRICT, N. MEX. 395

Phair, George, 1952, Radioactive Tertiary porphyries in the Central City district,

Colo., and their bearing on pitchblende deposition: U. S. Geol. Survey Trace

Elements Inv. Rept. 247, U. S. Atomic Energy Tech. Inf. Service, Oak Ridge,

Tenn. 

Rankama, Kalervo, and Sahama, T. G., 1950, Geochemistry: Chicago, Univ.

Chicago Press, 911 p. 

Head, C. B., and Wood, G. H., 1947, Distribution and correlation of Pennsylvanian

rocks in late Paleozoic sedimentary basins of northern New Mexico: Jour.

Geol., v. 55, p. 220-237. 

Zeller, H. D., and Baltz, E. H., Jr., 1954, Uranium-bearing copper deposits in the

Coyote district, Mora County, N. Mex.: U. S. Geol. Survey Circ. 334.

INDEX

Page

Abiquiu district-____________-_._ 392 

Abo formation_________________ 392,394 

Abstract._...__....___...._..____ 343

Adsorption of uranium_____ 383,386-387,389-391 

Aluminum___________________ 372-373 

Amphibolite___.___.._____-.__.. 347 

Analyses, chemical..______ 357-366,372-377,381 

radiochemical_..._____.____.... 377

rapid colorimetric _ _ . __ _ 377

spectrographic.. __ __________ 372-377

Aqua Zarca sandstone lentils.._ __._ 392

Arkose_... . 349,351-353,356,385,388,390

Arkosic pebble conglomerate.-_____ 352-353,357

sandstone-___-_____ 352,370-372,378-379

Arsenic 372,374,376,377,381

Azurite __~__ ._ __._ 369

Barite _____.__.___.__..__.. 354

Barium __.___.___._______.. 372-373 

Basalt flows___________________ 355 

Bernal formation... __ __...__ _ 355 

Beryllium..........._.______... 376-377,385

Betaflte____________________ 385 

Big Indian Wash district____________ 392 

Bismuth...__..__..._.___... 372,376,385" 

Bornite __-___ _ __.. 369,384 

Boron. .__..._._.___....__ 374-375

Brachiopods.. __.___.______ 350,354 

__...._________.____ 350

Calcite ________ 354,369,380,388,389,390,391 

Calcium__________________ 372-373,389 

Carbonaceous shale_________ 356,357,367-368 

Carbonized wood.__......_. 369-370,383-384,393

Chacon..__.________________ 349 

Chalcoclte-_______ .. 354,369,377,384,385 

Chaleopyrite - _ 371,379,380,384,388,391,393 

Chinle formation_______________ 392 

Chromium___________________ 374-375 

Cobalt... . .__._.____ 374-375 

Cobre Basin district_______________ 392 

Copper. 356-370,379,380-385,387,388,390-393 

Copper City district. .___.__...... 392

Corals_______________________ 350 

Covellite. .._ ... 369,377,384 

Coyote Creek..________________ 344 

Cuba district__________________.. 392 

Cutler formation . _ ______ 392,394 

Cyclothems__________________ 354

Diabase. __ ___________._._ 347

Digenite _________.___...____ 369

Diorite..________________.___ 347

Elk Mountain district 385

Equivalent uranium (elJ)_-__. .. 357-368,

371,372-373,381-382

Euxenite-______________.-__--. 385

Page 

Feldspar-__... ...._ 380,388,390

Fergusonite. . .. 385 

Fluviatile sandstone limit __ _____ 355,356

Gallinas district__-______________ 392 

Gallium 374-375

Garo uranium property_____________ 392 

Geochemical prospecting anomalies______ 382 

Germanium__________________ 372,381 

Glorieta sandstone member. ________ 347,355 

Gneiss. ___________ _....... 347

Granite______________________ 347 

Gummite 385

Hatchettolite.______ ___-__ 385 

Hematite _.... 379,380,388,390,391,394 

Huerfano Park______.__________ 392 

Hydrothermal leaching_____________ 389 

Hypselentoma................................. 354

Ionium.______...__ ________ 371,376 

Iron .. 371,372-373,383,388,389,391

Jarosa syncline 347 

Jemez Springs district _ _ _____ 392

Kolrn...___________..__.______ 390

La Veta Pass area____ __._____ 392 

Leaching of uranium .. .. _.._ 371 

Lead ..__..__ . .... 372-373,377,381

Limestone ._ ____ 349,354,357,366,392 

Limonite__________.___.______ 391 

Lithium _. _ ... ........ 385

Lockhart Canyon-Indian Creek area, Utah 392

Magdalena group... . 346,349-350,356 

Magnesium.. . .. . 372-373 

Malachite __ ._ 369,371,379,387,393 

Manganese-_____._______-__ 374-375,388 

Marble Falls limestone____________ 350 

Maroon formation. _. .. 392.394 

Metatyuyamunite_.___ 370,371,378-379 

Micaceous sandstone- _ -- . 357 

Mollusks_____________________ 350 

Molybdenum-_........ .... 374-375,381

Montmorillonite_________________ 389 

Morrison formation.....__..__ . 381,393

Muscovite.__-_________-_ __ 380

Nacimiento uplift._-__-_______.__ 392 

Nickel 374-375

Niobium _ 385,391

Nontronite 380,388,389

Ocate anticline______________._ 347

area..__--__ __ .. 345

Ojo Caliente district- _____...___ 385

Paragenetic sequence_______-___--.- 385

397
398 INDEX

Page 

Pegmatite-. . . .. 347,385,391

Petaca district__________________ 385 

Phosphorus . . 372 

Pitchblende 384

Potassium_._ _______________ 372-373 

Poleo sandstone lentils. ____________ 392 

Pyrite _ 369,384

Quartz.__._......._...__.. 380,

Quartzite____________________ 347

Radioactive equilibrium.._ ...... 371,381-382

Rare earths. ..... 372,381,389-391

Rociada district _........... .......... 385

Rocky Mountains _.__... _.____. 345 

Roscoelite . . - .. 379 

Rowe-Mora geosyncllne.----------_------ 346

Samarskite___-____-_________ 385 

San Andres formation ... 347 

Sandia formation _.._......__._ 349

Sandstone 349,356,371,372,379,381,388-394

Sangre de Cristo formation . _. 346,

347,349-355,356,378,391-394

Santa Rosa sandstone ... 355 

Scandium..._. ............___ 376-377

Schist- - ' . 347

Scholle district 392

Selenium....._._.......__._ 357-358,360-363

Shale 349,366,369,371,378,379,386,387,391,392 

Shale, copper-bearing carbonaceous . 345

Page 

Shinaramp formation. . .... 381,393

Silicon..-. . . 372-373

Siltstone 354,356,357,370,379,386-387,393 

Silver..... __...__...... 374-375

Smithwlck shale ----- . 350

Sodium____________________- 372-373 

Strontium___________________ 374-375

Tantalum ... . . 385,391 

Thorium 385,391

Titanium_______-...__..._____ 374-375 

Tourmaline 380

TurquUlo Valley__-----_-_ - .- -- 345

Unconformity ___-_-__ ____ 349 

Uraninite . .- 369,379,385

Uranium_..------.----.-- ----.---.- -__ 356,

370,371,378-380,382,383,385-386,388-394 

Uranium daughter elements ..._ _.... 377

Uranophane 385

Vanadium- 370,376-377,378,379,381,385-391,393 

Vanadium oxide--- -- --- 359-363,381 

Vitraln _ . __.__-_ 369 

Volborthlte 369

Volcanic plugs_______________ - _ 355

Water, uranium content____-______ 386

Zinc____ _-_ 374-375 

Zirconium..-_-------___...______ 374-375

Zunl Mountain district____________ 392