Uranium Resources of 

Northwestern NewMexico

GEOLOGICAL SURVEY PROFESSIONAL PAPER 603

Prepared on behalf of the

U.S. Atomic Energy Commission
Uranium Resources of 

Northwestern NewMexicc

By LOWELL S. HILPERT

GEOLOGICAL SURVEY PROFESSIONAL PAPER 603

Prepared on behalf of the

U.S. Atomic Energy Commission

A description of the stratigraphic and structural 

relations of the various types of uranium deposits 

in one of the world''s great uranium-producing 

regions

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1969
UNITED STATES DEPARTMENT OF THE INTERIOR 

WALTER J. HICKEL, Secretary

GEOLOGICAL SURVEY 

William T. Pecora, Director

Library of Congress catalog-card No. OS 68-390

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

Washington, D.C. 20402
CONTENTS

Abstract_ __.----_____-__--_____-__-___.__________

Introduction _______________________________________

Purpose and scope of this report._________________

Geography __________________________________

Previous investigations._________________________

Sources of data and methods of study _____________

Geologic nomenclature-_________________________

Acknowledgments__ _ __________________________

History of mining and ore production _________________

Geologic setting.___________________________________

Stratigraphy.______________________________________

Rocks of Precambrian age_______________________

Ortega Quartzite of Just (1937) and associated 

rocks_ _ __________________________________

Rocks of Cambrian (?) age_ ______________________

Rocks of Devonian age__________________________

Elbert Formation.__________________________

Rocks of Mississippian age_______________________

Leadville Limestone.________________________

Caloso Formation of Kelley and Silver (1952), 

Kelly Limestone, and Arroyo Penasco Formation_ ____________________________________

Rocks of Pennsylvania^ age______________________

Molas, Hermosa, and lower part of Rico Formations ____________________________________

Sandia Formation_________________________

Madera Limestone._________________________

Sandstone and siltstone____________________

Rocks of Permian age.__________________________

Bursum Formation________________________

Abo Formation.____________________________

Cutler Formation.__________________________

Yeso Formation and Glorieta Sandstone_____

San Andres Limestone_____________________

Bernal Formation.__________________________

Rocks of Triassic age__________________________

Moenkopi(?) Formation.____________________

Chinle Formation.._________________________

West and south sides of the San Juan Basin. 

Shinarump Member_______________

Lower red member.________________

Petrified Forest Member and included 

Sonsela Sandstone Bed.___________

East side of the San Juan Basin __________

Agua Zarca Sandstone Member and 

Poleo Sandstone Lentil-.__________

Dockum Formation._______________________

Wingate Sandstone.________________________

Rocks of Jurassic age___________________________

Entrada Sandstone________________________

Todilto Limestone._________________________

Summerville Formation____________________

Bluff Sandstone__________________________

Morrison Formation ________________________

Pate

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Stratigraphy Continued

Rocks of Jurassic age Continued 

Morrison Formation Continued

Salt Wash Member.. ___ _. _ ____

Recapture Member. ____________________

Westwater Canyon Member. ____________

Brushy Basin Member_ _________________

Rocks of Cretaceous age___ ______________________

Dakota Sandstone. __________-_-_-___-_-____

Mancos Shale______--_____-_-_-___-_-------

Gallup Sandstone___ ________________________

Crevasse Canyon Formation. ________________

Point Lookout Sandstone. ___________________

Menefee Formation. ________________________

Cliff House Sandstone. ______________________

Mesaverde Group undivided- _______-__--_-_-

Lewis Shale _ __ _________________ -__

Pictured Cliffs Sandstone, _______ _ _________

Fruitland Formation and Kirtland Shale ____

Ojo Alamo Sandstone. _____________-__----__

Animas Formation (Upper Cretaceous and 

Paleocene) ____-________-__---_-____------

Rocks of Tertiary age______ __________________

San Juan Basin___----___---_---___-,_-------

Nacimiento Formation. _________________

San Jose Formation. ____________________

Chuska Sandstone. _____________________

Datil section-___-------_-----_-_------ --

Baca Formation.. _____-___-_-_-_--__---

Datil Formation_--__--__-------------_-

Rio Grande trough and vicinity. _____________

Older volcanic rocks of Jemez Mountains. _ _ 

Galisteo Formation______--__-_-_-------

Espinaso Volcanics of Stearns (1943) __--__ 

Popotosa Formation. ___________________

Sante Fe Group (Miocene to Pleistocene?) _ _

Intrusive rocks of varied composition and form_ _

Structure. _________-___------_---------------------

Geologic history. ______-_____--__---_-------_-------

Uranium deposits___-___-_--_-----------------------

Peneconcordant deposits in sandstone____ ________

Morrison Formation, __________-_-_-__--_-_-

Ambrosia Lake district. _________________

Stratigraphy. ________--_--_------_-

Structure- __-____-_-----_--_-------

Mineralogy and form_ ____________

Stratigraphic relations of the deposits. _ 

Structural relations of the deposits..-- 

Color relations of the host rocks. _____

Laguna district..-..--.-.---------------

Stratigraphy- _______-_-_-___--_----

Structure. ___________--__----_-_-__

Mineralogy and form_ ____________

Stratigraphic relations of the deposits _

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IV CONTENTS

Uranium deposits Continued

Peneconcordant deposits in sandstone Continued 

Morrison Formation Continued 

Laguna district Continued

Structural relations of the deposits.. __ 

Color relations of the host rocks _ _____

Gallup district. _________________________

Stratigraphy. ..___________---__-____

Structure. _________________________

Mineralogy and habits. _____________

Stratigraphic and structural relations 

of the deposits- __________________

Color relations of the host rocks _ _____

Shiprock district... _____________________

Stratigraphy. ..________---_-___--___

Structure. _________________________

Mineralogy and habits. _____________

Structural relations of the deposits____

Chuska district- ________________________

Stratigraphy-. _____________________

Structure-- _--_--_----------------_

Mineralogy and form __ ____________

Structural relations of the deposits. ___ 

Other districts or areas. _________________

Pennsylvanian, Permian, and Triassic rocks____

Mineralogy and habits. ________-_---_-__

Stratigraphic and structural relations______

Cretaceous rocks. _ ________________________

Mineralogy and habits ___ _ _____________

Stratigraphic and structural relations _ _ __

Tertiary and Quaternary rocks _ _ ____________

Mineralogy and habits ___ _ _ ________.- .

Stratigraphic and structural relations______

Peneconcordant deposits in Todilto Limestone and 

adjacent formations. ______________________

Stratigraphy. ______________________________

Structure. _ ________________________________

Mineralogy and form____ ____________________

Stratigraphic relations of the deposits _________

Structural relations of the deposits. _ __________

Peneconcordant deposits in shale and coal__________

Mineralogy and habits ___ __________________

Stratigraphic and structural relations __________

Vein deposits______-_-____-__-__-____--_________

Deposits in sedimentary rocks. _ ______________

Mineralogy and habits ___ __-_--_____-__

Stratigraphic and structural relations ______

Deposits in igneous rocks_ _ __________________

Mineralogy, habits, and structural relations. 

Deposits in metamorphic rocks__ _____________

Mineralogy, habits, and structural relations. 

Distribution of elements in the ores ___________________

Purpose and methods of analysis __ ______________

Ore sample groups and their characteristics. _______

Exceptional characteristics of some ore sample 

groups __________________________________

Espinaso V olcanics of Stearns (1943) __________

Popotosa Formation... _____________________

Morrison Formation. _______________________

Morrison Formation (Woodrow deposit)-- _____

Todilto Limestone____.._____________________

Cutler Formation. __________________________

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Distribution of elements in the ores Continued

Exceptional characteristics of some ore sample

groups Continued 

San Andres Limestone _ _-_----_____________

Madera Limestone. _________________________

Summary and conclusions _ _____________________

Distribution of elements in the Todilto Limestone. _ 

Purpose and methods of analysis, _ __________

Elements that decrease in concentration away 

from ore_____-___________________________

Elements that increase in concentration away 

from ore__ _______________________________

Elements concentrated between ore and barren 

ground- _________________________________

Elements in the gypsum unit. ________________

Summary and conclusions __ ________________

Ages of emplacement-. __________________________

Geologic controls. ______________________________

Origin __ _________ ___ ________ _____ _ ____

Uranium resources__________________________________

Precambrian rocks______________________________

Ortega Quartzite of Just (1937) and other rocks. 

Cambrian(?) rocks______________________________

Unnamed conglomeratic sandstone and shale. __ 

Devonian rccks_________________________________

Elbert Formation___________________________

Mississippian rocks. ____________________________

Leadville Limestone, Caloso Formation o* Kelley 

and Silver (1952), Kelly Limestone, and 

Arroyo Penasco Formation _ ______________

Pennsylvanian rocks ___ _______________________

Molas, Hermosa, and lower part of Rico Formar 

tions ____________________________________

Sandia Formation __ _______________________

Madera Limestone__ ________________________

Permian rocks _ _______________________________

Bursum Formation__________________________

Abo Formation_____________________ ________

Cutler Formation___________________________

Yeso Formation and Glorieta San dstone. _______

San Andres Limestone- ________-_-______-_-_-

Bernal Formation _ ________________________

Triassic iocks_ __ ______________________________

Moenkopi(?) Formation ____ _______________

Chinle Formation _ ________________________

Dockum Formation. ________________________

Wingate Sandstone. __._____-_-__________-_-

Jurassic rocks ____ ____________________________

Entrada Sandstone __ _____________________

Todilto Limestone _ _______________________

Summerville Formation_____________________

Bluff Sandstone ___ ________________ _ _ _

Morrison Formation ___ ___________________

Cretaceous rocks __ ____________________________

Dakota Sandstone_______.__________________

Mancos Shale, Gallup Sandstone, Crevasse 

Canyon Formation, Point Lookout Sandstone, Menefee Formation, Cliff HOUF«* Sandstone, Lewis Shale, Pictured Cliffs Sandstone, 

Fruitland Formation, Kirtland Shale, Ojo 

Alamo Sandstone, and Animas Formation 

( Upper Cretaceous and Paleocene) ___________

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CONTENTS

Uranium resources Continued P&ge 

Tertiary rocks_ _________________________________ 151

Nacimiento and San Jose Formations. 

Chuska Sandstone.________________

Baca Formation.__________________

Datil Formation.._________________

Galisteo Formation._______________

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Popotosa Formation ____________________ 151

Santa Fe Group (Miocene to Pleistocene?)____ 152

Uranium resources Continued 

Tertiary rocks Continued

Older volcanic rocks of Jemez Mountains, 

Espinaso Volcanics of Stearns (1943), Cieneguilla Limburgite of Stearns (1953), and 

intrusive rocks of varied composition and 

form... _ ___. ____________ _. ____ 152

Areas lecommended for exploration,. _ _________________ 152

Literature cited __ _________________________________ 154

Index __________ __ _______________ ____ .. 161

PLATE

ILLUSTRATIONS

[Plates 1-4 are in pocket]

Geologic map of uranium deposits in northwestern New Mexico.

Generalized correlation chart of the principal stratigraphic units in northwestern New Mexico. 

Isopach map, sample localities, and the uranium deposits of the Todilto Limestone. 

Geologic sections of Morrison Formation in the Ambrosia Lake district.

FIGURE 1. Index map of northwestern New Mexico __ ______________________-_-_--___--------_-------__-______ 3

2. Chart showing yearly production of uranium ores, northwestern New Mexico. __________________________ 7

3. Simplified tectonic map of northwestern New Mexico. ___________-_______-__-----------_-----_--___.- 27

4. Map of trend-type ore deposits in T. 14 N., R. 9 W-_____-_____-_-----_----------------_-----------_- 64

5. Cross section of Section 23 ore body. ___________________________---__-_-__--_--------_-------._____ 66

6. Map showing ore deposits and favorable belts, Ambrosia Lake district. _________-__--______----________ 67

7. Map of part of Laguna district showing uranium deposits in Morrison Formation _____________________ 70

8. Generalized geologic section of Morrison Formation between Ambrosia Lake and Laguna districts. ________ 71

9. Generalized structure map of Laguna area_______________-______-________-_-------_---------_-_-_--_ 73

10. Field sketch showing displacement of Jackpile uranium deposit by diabase sill _ ________________________ 75

11. Geologic sections in western part of Gallup district________-_--___----_---___--_---_--------___--_-_- 79

12. Geologic map and sections of the Foutz 3 mine___________________-_______________-_____---_-_-_-_-_- 82

13. Autoradiograph of ore specimen, Foutz 3 mine. ________________ --_-_-______-_-_-_______---_-_-____-- 83

14. Map of main part of Chuska district, showing deposits in Morrison Formation. _________________________ 85

15. Map of Diamond 2 mine_______________________________________-_________--___--____---___-___-_- 91

16. Geologic map of upper Alamosa Creek valley. _____________________--________-__-_----_-----_---_-_- 96

17. Geologic map of Red Basin claims_-________________---_--__-__-_---_---_-__---------------_---__-- 98

18. Map showing sample localities and contents of uranium in Santa Fe Group. __-__--_-_-__-_--__-_-_-_--- 99

19. Geologic section of uranium deposits in Todilto Limestone__ _ _________________________________________ 103

20. Map showing areas recommended for exploration. _ __________________________________________________ 153

TABLES

TABLES 1, 2. Uranium ore production from Page

1. Northwestern New Mexico___--_--______________-_--__--_--__--_--_------------------------ 6

2. Northwestern New Mexico, by districts. ____________________--___-___-_--_-----_------------- 8

3. Uranium ores classified by age and type of host rock________--___-_______-___----_-----_------------- 9

4. Uranium deposits, by county, in northwestern New Mexico.________-_ ________-__-_______------------- 32

5. Analyses of mill pulp samples from volcanic and other rocks_ __________________-_________-----_-_-_--- 108

6. Analyses of mill pulp samples from limestone_______________. _______________-__-__-__-_---_-_-_-_--- 113

7-9. Concentrations of 

7. Eight major elements in 12 sample groups. _ ______._____________________-___-_____-_--_-_-_--- 118

8. Nineteen minor elements in 12 sample groups. ________________________--________------_------- 120

9. Uranium and other selected elements in 12 sample groups__-___________________-__---_-__------ 122

10. Geometric means of 16 selected elements in ore sample groups___________________________-----_------- 124

11. Analyses of samples of barren and uraniferous Todilto Limestone__-_---_-__------------_--_----------- 127

12-14. Concentrations of 

12. Eight major elements in zones of Todilto Limestone. _ ___________________________---_-_-_----- 134

13. Thirteen minor elements in zones of Todilto Limestone. _______________-_-_______---_-----_--- 135

14. Uranium and other selected elements in zones of Todilto Limestone. ______________-----___--_-- 136

15. Analyses of gypsum from Todilto Limestone. ________________________________-___-_-___-_----------- 138

16. Listing of uranium deposits, mine reserves, and potential for undiscovered resources in etratigraphic units, _ 148

URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

By LOWELL S. HJLPERT

ABSTRACT

Uranium deposits in northwestern New Mexico occur in 

about 30 formational units that range in age from Precambrian to Quaternary. The most economically important deposits are peneconcordant and occur in sandstone, limestone, 

shale, and coal. Less economically important vein deposits occur 

in metamorphic, igneous, and miscellaneous sedimentary rocks. 

Of the peneconcordant deposits, the most economically important ones occur in sandstone in the Morrison Formation; others 

occur in limestone beds of the Todilto Limestone and in sandstone beds of the Dakota Sandstone.

From 1950 to 1964, northwestern New Mexico yielded more 

than 23 million tons of uranium ore, which averaged 0.22 

percent U3O8 and had an average U: V ratio of about 2:1. In 

the Shiprock district, about 30,000 tons of vanadiferous ores 

averaged 2.55 percent V2O5.

About two-thirds of the uranium output was from the 

Ambrosia Lake district and nearly a third was from the Laguna 

district. Production reached a peak of 3.7 million tons in 1960, 

after which it declined to about 2.1 million tons in 1964. 

During the 1956-64 period, production was 42 percent of the 

national output. More than 95 percent of the ore came from 

sandstone, 4 percent come from limestone, and lees than 

1 percent came from carbonaceous shale, coal, and igneous 

rocks. More than 99 percent of the output was from rocks 

of Jurassic age; the remainder came from rocks that range in 

age from Pennsylvanian to Tertiary.

As of January 1966, mine reserves totaled 29.7 million tons 

of material that averaged 0.23 percent U3O8. About 60 percent 

of these reserves was in the Ambrosia Lake district, in the 

Morrison Formation. In addition, resources largely in the periphery of the mine reserves in the district probably total as 

much as several million tons of material that would average 

about 0.1 percent U3O8.

Undiscovered or potential reserves probably are several 

times the combined production and mine reserves estimated 

as of January 1966 and may amount to as much as 200 million 

tons of material, expected to average about 0.25 percent UsOs. 

These resources are expected to be almost entirely peneconcordant deposits, principally in large ones in sandstone lenses 

in the Morrison Formation, but important deposits also are 

anticipated in sandstone lenses in the Dakota Sandstone and 

in limestone beds in the Todilto Limestone. Most of these 

resources probably are concentrated in the southern San Juan 

mineral belt, now generally referred to as the Grants mineral 

belt. This is a geologically favorable area that is roughly 25 

miles wide and about 100 miles long, extending from the Rio 

Grande trough westward across the south end of the San Juan

Basin to near the Arizona line. Some important resources 

also are anticipated in the Chuska and Shiprock districts in 

the Morrison Formation; most of the rest probably are scattered in various formations of late Paleozoic, Mesozoic, rnd 

Tertiary ages. The resources will lie from near outcrop to 

several thousand feet below the surface.

Principal controls of the peneconcordant deposits were the 

original sedimentary basins of the host rocks, structural troughs 

or depressions along basin margins, and a variety of smaller 

scale sedimentary and tectonic structural features. Intraforriational flowage structures were important controls in limestone 

and were minor controls in sandstone. Faults and other fractures exerted only local control on the primary deposits, but 

they greatly influenced the disposition of the secondary or 

oxidized deposits.

Structural and stratigraphic data indicate that the peneconcordant deposits were emplaced shortly after deposition of 

the host rocks and were localized principally along the margins 

of sedimentary basins. The most likely age of deposition of the 

deposits in the Todilto Limestone and Morrison Formation 

was Late Jurassic and in the Dakota Sandstone was Oretacecns.

Structural data and general age relations of the deposits 

indicate that the source of the uranium was the adjacent 

highland areas and the host rocks. Uranium probably vas 

leached from these rocks, carried basinward in dilute solutions through unconsolidated sediments, and precipitated by 

the reduction of carbonaceous debris and by other unkncwn 

means. No evidence is convincing that magmatic fluids played 

any significant part in the emplacement of the peneconcord-mt 

deposits.

INTRODUCTION 

PURPOSE AND SCOPE OF THIS REPORT

This report is an appraisal of the uranium resources 

of northwestern New Mexico and is one of a series 

of similar reports planned to appraise the uranium resources of the Colorado Plateau. The general geography, history of uranium mining, general geolo.'ry, 

and uranium occurrences are discussed, the miner ale Try 

and habits of the known deposits in the various districts and areas are described, and the relations of the 

deposits to the stratigraphy, structure, and geoloq^c 

environment are reviewed. The uranium resources are 

appraised as to rock types and geologic environment, 

formations, and areas.

1
URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

GEOGRAPHY

Northwestern New Mexico here is considered to be 

west of long 10° and north of lat 34°; it encompasses 

an area of about 35,000 square miles roughly a third 

of the State (fig. 1). The area includes parts of three 

physiographic provinces. The western two-thirds is in 

the Colorado Plateaus province, and the eastern onethird is in the Southern Rocky Mountains province on 

the north and in the Basin and Range province on the 

south (Fenneman, 1931). The part in the Colorado 

Plateaus province is in the Navajo section (Fenneman, 

1931) on the north and in the Datil section, also referred to as the Datil volcanic field, on the south. 

The dominant feature of the Navajo section is the San 

Juan Basin, which is a broad topographic basinlike depression characterized by broad open valleys and mesas 

and local deeply incised drainage features. The basin 

is flanked on the west by the Chuska Mountains, on the 

south by the Zuni Mountains, and on the east by the 

ranges of the Southern Rocky Mountains province. The 

Datil section constitutes the southeastern part of the 

Colorado Plateau and is characterized by lava plains, 

lava-capped mesas, and benches; it is dominated locally by the Zuni, Ladron, and Magdalena Mountains 

and by Mount Taylor. The part of the area in the 

Southern Rocky Mountains province is marked by the 

rather broad and fairly well dissected Sierra Nacimiento, by the San Pedro, Jemez, and San Juan, Mountains, and the part in the Basin and Range province 

by the broad valley of the Rio Grande and the northward-trending ranges, principally the Manzano and 

Sandia Mountains, that lie along the east margin of 

that valley.

The altitude of the area generally ranges from about 

5,000 to 8,000 feet above sea level and the mountain 

crests from 8,000 to 11,000 feet above sea level. The climate is mostly semiarid, the annual precipitation 

ranging from 5 to 15 inches per year and averaging 

about 10 inches per year. The summers are generally 

hot, the winters moderately cold, and the mean yearly 

temperature ranges from about 45° to about 60°F for 

different parts of the area. Vegetation is sparse, and 

consists mostly of desert shrub species, mainly sage and 

juniper in the lower altitudes, and forests of pine, fir, 

and spruce in the higher altitudes.

Drainage is mostly confined to two basins separated 

by the Continental Divide, which trends northeastward 

through the approximate center of the area. In the 

western basin the drainage mostly flows into the San 

Juan River, and thence westward to the Colorado River in southern Utah. In the eastern basin, the drainage flows into the Rio Grande and thence southward

into the Gulf of Mexico. A small area south of the 

Chuska Mountains and west of the Continental Divide 

drains westward into Arizona and into the Little Colorado River. Water is scarce except along the principal streams and in the higher parts of the mountains.

PREVIOUS INVESTIGATIONS

Northwestern New Mexico has received much attention from geologists, dating from preterr^torial time 

(Wislizenus, 1848). During territorial time the area 

was visited and mapped between the years 1850 and 

1880 by several of the so-called military, railroad, and 

territorial surveys (Simpson, 1850; Blake, 1856; Marcou, 1856, 1858; Newberry, 1861, 1876; Howell, 1875; 

Gilbert, 1875; Holmes, 1877; Stevenson, 1881). Since 

1880, geologic work has been extensive and varied, and 

the reader is referred to Lindgren, Graton, and Gordon (1910), Darton (1910,1928), Reeside (1924), Baker, Dane, and Reeside (1936), Hunt (1938, 1956), and 

Stearns (1953) for general bibliographic information. 

Other references, where pertinent, are cited in the text.

Uranium investigations in northwesterr New Mexico started in the Shiprock district, San Juan County, 

and the area was mapped and studied by D. C. Duncan 

and W. L. Stokes in October and November 1942 and 

by Stokes and G. M. Sowers in April 1945 (Stokes, 

1951). In 1948, the U.S. Atomic Energy Commission 

and the U.S. Geological Survey started extensive geological investigations and completed some exploration 

of the uranium-bearing formations to appraise the 

uranium resources of the Colorado Plateau. The results 

of some of this work have been published, other reports are forthcoming, and some work is yet in progress, particularly in the Ambrosia Lake district.

SOURCES OF DATA AND METHODS OF STUDY

Information used in this report is from records of 

uranium ore production and uranium reserves obtained 

from the Grand Junction Operations Office, Division 

of Raw Materials, U.S. Atomic Energy Commission; 

from data contained in many published renorts and in 

the files of the U.S. Atomic Energy Commission and 

U.S. Geological Survey; from data obtained from 

many individuals and companies in the mining industry ; and from data obtained by the observations of the 

author and his colleagues. Fieldwork was done mostly 

during the summers of 1954-56, and periodic field visits 

were made during the summers of 1957-58. The fieldwork was largely reconnaissance, but most of the more 

important deposits were examined and some were 

selectively mapped to determine their habits and geologic relations. In the more economically important 

districts, drilling records of literally thousands of
INTRODUCTION

109° 108° 107° 106°

MC KINLEY 

"D I S T R I C

50 MILES

1. Northwestern New Mexico.
URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

holes were utilized for geologic information on the 

stratigraphic and structural relations of the deposits, 

and in some critical areas, stratigraphic sections were 

measured. During the 1955-56 field season and to some 

extent in 1957-58, the work was concentrated largely 

on abstracting the drilling records of the exploration 

companies in the Ambrosia Lake district.

Most of the data in this report are based on work 

done prior to 1959. Delay in completion of the report, 

however, made it desirable to update the mine production data to the end of 1964 and to locate and describe the pertinent features of deposits found after 

1958. This information is shown on the illustrations 

as well as in the text. The text has been revised to benefit from the geologic literature published from 1959 

to 1962.

GEOLOGIC NOMENCLATURE

Since this report was prepared, the age of the Ojo 

Alamo Sandstone has been changed from Late Cretaceous to Paleocene (Balz and others, 1966) ; the age of 

the Blanco Basin Formation has been changed from 

Oligocene( ?) to Eocene (Steveii and others, 1967) ; and 

the Potosi Volcanic Series has been changed to Potosi Volcanic Group, the name being used only near 

the type area in Colorado (Luedke and Burbank, 1963).

ACKNOWLEDGMENTS

It is not possible to give complete credit to the many 

companies and individuals whose interest and contributions make a synthesis of this type possible, and 

failure to acknowledge any assistance given is through 

oversight rather than through intent. I am especially 

grateful to the staffs and individuals in the following 

companies who were so generous in granting access to 

their records and properties:

American Metals Co., Ltd.

Anderson Development Co.

Calumet Hecla, Inc.

Colamer Corp.

E. J. Longyear Co.

Flat Top Mining Co.

Food Machinery & Chemical Corp. (Westvaco)

Four Corners Exploration Co.

Four Corners Uranium Corp.

Hanosh Mines, Inc.

Haystack Mountain and Development Co. 

(Santa Fe Railway)

Holly Minerals Corp.

Homestake Mining Co.

Homestake-Sapin Partners

Humble Oil & Refining Co.

Kennac Nuclear Fuels Corp.

Kerr-McGee Oil Industries, Inc.

L-Bar Cattle Co.

Mid-Continent Exploration Co.

Mid-Continent Uranium Corp.

National Lead Co.

New Jersey Zinc Co.

New Mexico & Arizona Land Co.

Pacific Uranium Mines Co.

Phillips Petroleum Co.

Rare Metals Corp. of America

Rimrock Mining Co.

Rio de Oro Uranium Mines, Inc.

Sabre-Pinon Corp.

Sabre Uranium Corp.

San Jacinto Petroleum Corp.

See Tee Mining Co.

The Anaconda Co.

Tidewater Oil Co.

United Nuclear Corp.

United Western Minerals Co.

Special thanks are also given the following individuals, who through their interest or involvement 

in the work contributed much of their tim^s and assistance:

L. J. Reynolds and Ross Martinez, of Associated 

Uranium Producers; O. E. Maiiol and I. J. Rapaport, 

of Four Corners Exploration Co.; T. O. Evans, of Haystack Mountain and Development Co. (Santa Fe Railway) ; Paul Melancoii, of Holly Minerals Corp.; E. E. 

Jones, of Kerr-McGee Oil Industries, Inc.; C. N. 

Holmes, of Phillips Petroleum Co.; J. W. Knaebel 

and R. D. Lynn, of The Anaconda Co.; and E. G. 

Robinson and Helge Laursen, of Tidewater Oil Co.

Thanks are also extended to the following individuals for their courtesy in contributing geologic information and (or) granting access to their properties:

Richard Bokum; E. P. Chapman, Jr., and J. A. 

Wood, of Chapman and Wood; Henry Elkins; Thomas 

Hyde; Malcolm Larson; Howard Maior; Robert 

Sayre; and J. Q. St. Clair. Thanks are also extended to 

the Council of the Acoma Pueblo for granting access to 

the Acoma Reservation.

V. L. Freeman assisted in the work from July 1954 

to June 1955, and A. F. Corey assisted from July 1955 

to April 1958. H. C. Granger provided much assistance in his technical review of the manuscript. To these 

individuals and my other colleagues in tl °- U.S. Geological Survey, I wish to express my appreciation for 

the assistance given. Special thanks are also due the 

many individuals on the staff of the U.S. Atomic 

Energy Commission, Grand Junction Operations Office, for their generous assistance. The work was done 

by the U.S. Geological Survey on behalf of the Divi-
HISTORY OF MINING AND ORE PRODUCTION

sion of Eaw Materials, U.S. Atomic Energy Commision.

HISTORY OF MINING AND ORE 

PRODUCTION

Uranium minerals have been known in northwestern New Mexico for many years, but were little more 

than curiosities until carnotite deposits were discovered west of Shiprock in 1918. Little ore was produced from these deposits until the 1942^4 period, 

when several thousand tons was mined for vanadium 

content. In 1948, prospecting was stimulated by the 

U.S. Atomic Energy Commission's ore-buying schedule announced in Circulars 1 and 2 and, subsequently, 

by additional incentives.1 New deposits were found in 

the Shiprock area and west of Sanostee, San Juan 

County. Discoveries of these deposits were followed by 

those near Grants and Laguna, in McKinley and Valencia Counties, respectively (pi. 1). Exploration for 

uranium in northwestern New Mexico, however, received little stimulus until the discovery of uranium in 

limestone in 1950 and the discovery of large uranium 

deposits in sandstone in 1955. Earlier discoveries were 

considered unimportant and were largely forgotten 

(Smith, 1954; Kelley, 1963). A_resume of the 1950 and 

1955 discoveries and closely related events is of interest 

because of the effects they had on subsequent developments and the importance of these developments to 

the uranium industry of the United States.

In the early spring of 1950, Paddy Martinez, a Navajo Indian, found yellow coatings on the Todilto 

Limestone outcrop in sec, 19, T. 13 N., E. 10 W., 

McKinley County. He subsequently learned that the 

discovery site was on Santa Fe Eailway Co. property, and brought the matter to the attention of T.O. 

Evans, a Santa Fe Eailway mining engineer. Evans 

examined the site on September 20, and thereafter 

recommended an exploratory drilling program which 

was initiated on November 15, 1950 (T.O. Evans, 

written commun., 1959). The exploration shortly resulted in the development of an important ore body, 

later worked as the Haystack mine, which at the end 

of 1958 had yielded more ore than any other deposit in 

the Todilto Limestone. The discovery of the Haystack 

deposit stimulated prospecting in the region, and led to 

the discovery of many other deposits in the Todilto 

Limestone and in sandstone along the outcrop of the 

Morrison Formation.

The first significant discovery of uranium in sandstone in the general area was made a few miles north 

of Grants at Poison Canyon on the outcrop of the

1 See Atomic Energy Commission Regulations, pt. 60, Domestic 

Uranium Program Circulars 1 to 6, inclusive, April 9, 1948; June 15, 

1948 ; February 7, 1949 ; and June 27, 1951.

Morrison Formation on January 4, 1951, by T.O. 

Evans. This deposit was later identified by the name 

Poison Canyon mine.

Two later discoveries in the Morrison Formation 

were of outstanding significance, the Jackpile deposit near Laguna, Valencia County, and the Dysart deposit near Ambrosia Lake, McKinley County. The 

Jackpile deposit was discovered on November 8, 1951, 

from a radioactive anomaly picked up by an Anaconda Copper Mining Co. plane in which Dale Terry 

was the observer and Woodrow House the pilot. The 

anomaly was confirmed the same day by a ground 

check made by Terry, and the following day, House 

and Terry returned to the site with J.D. "Jack" 

Knaebel, manager of Anaconda's New Mexico operations. During the examination of the outcrop, Terry 

referred to the discovery as "Jack's pile," later contracted to Jackpile (E.D. Lynn, oral commun., 1958.)

Discovery of the Jackpile did not have the impact 

on the industry that other discoveries had, although 

the Jackpile by 1958 had been developed to become the 

largest uranium mine in the United States from the 

standpoint of ore produced, reserves, and magnitude 

of operations. The lack of impact may seem surprising, 

because the Jackpile was discovered nearly 8 months 

before Charles Steen's discovery of the Mi Vida and 

more than a year before Vernon Pick's discovery of the 

Delta deposit in southeastern Utah. The Jackpile discovery, however, was made by the employees of a large 

company and was not publicized; also much time 

elapsed before development drilling revealed the great 

size of the deposit.

Discovery of the Dysart deposit, however, hr,d a 

great and almost immediate effect on the uranium industry, although it was found more than 3 years r.fter 

the Jackpile. Early in 1955, Louis Lothman reportedly 

found radioactive cuttings at the site of the M. K. 

Wadley's Dysart well, drilled in 1952 near the SW. cor. 

sec. 11, T. 14 N., E. 10 W., McKinley County. Lothman 

and Ellis Dunn then undertook a joint drilling verture 

in the ground just north of the Wadley-Dysart well, 

where the second drill hole penetrated mineralized 

ground about mid-April 1955. This discovery caught 

the public's fancy, just as had Steen's and Pick's discoveries, because each resulted from the efforts of an 

individual prospector. The resulting publicity st'mulated intensive exploration in the area and led to the 

discovery and development of several multimillior-ton 

deposits. By the end of 1958, a mining and milling industry of national importance flourished in the area.

Five principal uranium mining areas, or districts, 

in northwestern New Mexico justify description. Two
6 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

of these, the Shiprock and Chuska districts, are defined by the boundaries used by the U.S. Atomic Energy 

Commission, and extend into adjoining parts of Arizona, Utah, and Colorado. The other three, the Gallup, 

Ambrosia Lake, and Laguna districts, are in the central 

part of the area and are the most productive parts of 

the larger Grants mining district as defined by the 

Commission. The boundaries of these five districts are 

shown in figure 1.

A relatively small amount of mining for uranium 

has been done in other metal-mining districts or areas 

that do not require description.

From 1950 through 1964, more than 23 million tons 

of ore averaging 0.22 percent U3O8 was produced from 

northwestern New Mexico (table 1). This yield came 

from about 175 mines and largely from the Ambrosia 

Lake and Laguna districts (fig. 2). The area was not 

an important producer of uranium ore until 1956, 

however, when the Jackpile mine attained large-scale 

operation. The ore produced by this mine in 1956-57 

dwarfed the combined tonnage from all other mines, 

but in 1958 the Ambrosia Lake district started yielding large tonnages, and in that year northwestern New 

Mexico yielded about 1.9 million tons of ore 36 percent of the tonnage mined in the United States. The 

output continued to climb, reaching a peak in 1960 of 

about 3.7 million tons, after which it declined; yield 

was about 2.1 million tons in 1964. During the 1956- 

64 period, however, the output was 42 percent of that 

of the United States. The decline after 1960 stemmed 

largely from the saturated market, which resulted in 

the government's reduction and stretchout of mine 

quotas and reduction in the price offered for mill concentrates.

The district production is briefly reviewed in table 

2 in order of total output. The greatest yield has been 

from the Ambrosia Lake district. Initial mine output 

in the district was in 1950, after which it progressively 

increased, with two minor dips, until it peaked in 1962

with an output of about 2.9 million tons. (See fig. 2.) 

Through 1964, the district yielded 15.3 mill; on tons of 

ore, which averaged 0.22 percent U3O8 and C.15 percent 

V2O5 (table 2). This tonnage was 66 percent of the 

total output of northwestern New Mexico. The ore 

came from 64 mines, of which 43 were in limestone and 

21 were in sandstone. The sandstone orer however, 

constituted 94 percent of the total output ani averaged 

0.22 percent U3O8 , 0.15 percent V2O5 , and about 5 percent CaOO3 , generally referred to in the industry as 

lime. Through 1964, the output of limestone ores 

totaled about 939,000 tons, and had the same average 

grade for uranium and vanadium as the sandstone 

ores. At least one mine, the Zia, yielded a small mixed 

tonnage of sandstone-limestone ore.

Mining started in the Laguna district in 1952, and 

by the end of 1958 the district had produced about 3.3 

million tons of ore (fig. 2), which was about 70 

percent of the total production in northwestern New 

Mexico. By the end of 1964, the total output of about 

7.3 million tons, which came from nine mines, was 

about 32 percent of the total for northwestern New 

Mexico. This ore averaged 0.21 percent U3O? (table 2). 

Most of it came from the Jackpile mine, r.nd all but 

about 1,000 tons was ore from sandstone; this ore 

during the 1952-57 period had an average content of 

0.13 percent V2O5 , and during the 1954-58 period had 

an average lime content of about 1 percent. Three 

mines in the district produced ores from limestone; 

one of the mines, the Sandy, yielded mixed sandstonelimestone ore. The ore from these three min?® averaged 

0.13 percent U3O8 ; the vanadium content probably was 

low, but the average content is not known.

Output in the Gallup district started in 1952, and by 

the end of 1964 totaled about 384,000 tons of ore that 

averaged 0.22 percent U3O8 (table 2). This yield came 

from 13 mines, of which 10 produced ore from sandstone and 3 produced ore from carbonaceous" shale. The

TABLE 1. Uranium ore produced from northwestern New Mexico, 1950-64

All data furnished by courtesy of the U.S. Atomic Energy Commission. Data for the 1950-58 period were compiled by the author from records in the Co-nmission's flies, 

Grand Junction, Colo. Prior to 1950, and principally during World War II, about 10,000 tons of ore was produced from the Eastside Lease, Vanadium C irp. of America. 

Most of this ore, however, came from Arizona; it averaged about 0.30 percent UsOg and 2.50 percent VzOs, and during 1942-43 was mined for vanadium only]

Year

1950-------__-__________--_.

1951__ ____________________

1952________________---___._

1953--_-__----------_-__--__

1954__. _____________________

1955____________________.___

IQRfi

19o7__-__---_-___-__________

1958_____---________ ________

Tons

_______ 5,813

--.____ 1,011

_______ 22,998

_______ 84,598

_______ 196,161

_______ 262, 113

1 Iflfi fififi

--.____ 1,185,975

_______ 1.888.459

U3O8 Grade 

(weight 

percent)

0 21 

24 

22 

25 

36 

25 

26 

21 

21

1959.

1960.

1961.

1962-

1963-

1964.

Year

Total and weighted average.

Tons

3, 200, 779 

3, 730, 90,5 

3, 575, 589 

3, 450, 791 

2, 294, 892 

2, 093, 355

23, 099, 094

UsOa Grade 

(weight 

percent)

0 21 

21 

22 

23 

22 

23

0.22
ORE, IN THOUSANDS OF TONS

N N- ro rs^

S

I 

Ore discovered in Todilto Limestone

Ore discovered at Poison Canyon

r|l Jackpile deposit discovered
8 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

TABLE 2. Uranium ore produced, by district, from northwestern New Mexico, 1950-64

[Leaders (...) indicate no production or no assay. Data furnished by courtesy of the U.S. Atomic Energy Commission; the data for 1950-58 were compiled from records in

the Commission's flies, Grand Junction, Colo.]

Ambrosia Lake district

Year Grade (weight percent)

U3 08

1950 .

1961 . 1952 ......

1953. - -.

1954--... .

1955- -.

1956. .

1957. .

1958.-. .

1959--. -.

I960 ...

1961... .........

1962............

1968 -. .

1964..-..... .

.... ... ... 10

 ... . 779

.... 14,562

... . 66,248

.... 129,202

... ....... 166,859

------ 181,593

. 131,921

--.-.-. 670,035

... 2,196,335

.... ... 2,719,065

 . 2,623,718

 ... ... . 2,883,676

 1,872,512

... ... 1,677,285

V2O8 » CaCO3 2

0.35 0.19 

.36 .16 

.21 .20 

.25 .17 

.26 .17 

.22 .15 

.22 .16 

.23 .12 

.24 .16 

.22 .

.22 .

.23 .

.22 .

.22 .

.22 -

(10) 

(779) .

(14,562) 1.8 

(66,248) 1.6 

(129,202) 3.9 

(166,859) 5.0 

(181,527) 4.8 

(118,463) 5.8 

(22,506) 4.0

(810) 

(369) 

(36, 702) 

(52, 549) 

(66,913) 

(50, 453) 

(15, 749)

1,125 

10,063 

57, 474 

86,748 

906,397 

1, 027, 262 

1, 198, 291 

1, 001, 680

935,649 

868, 141 

503,654

371, 331 

339,266

Laguna district

Grade (weight percent)

UsOs

0.32 0.27 

.30 .20 

.61 .29 

.26 .16 

.27 .14 

.21 .10 

.20 .

.19 .

.19 .

.19 .

.24 .

.21 .

.24 .

V2Oj 3

(1, 125) 

(10, 063) 

(57, 474) 

(82, 595) 

(906, 397) 

(1, 026, 815)

CaCOa 2

3.1 

2.9 

.8 

.8 

.6

(56, 574) 

(84, 795) 

(906, 737) 

(1, 026, 815) 

(271, 573)

309 

3,136 

1,491

4,428 

12,588 

19, 421 

17, 459 

1,916 

75,584 

81, 955

55,880

40,042 

69,960

Gallup district

Grade (weigfct percent)

U3 08 V208 «

0.27 0.17 

.20 .14 

.17 .12 

.19 .15 

.21 .07 

.24 .08 

.24 .13 

. 19

.23 .

.21 .

.21 .

.23 .

.22 .

(309) 

(3, 136) 

(1,491) 

(4,428) 

(12, 588) 

(8, 535) 

(17, 3-'0)

CaCOjS

5.7 

1.3 

.7 

.6 

.5 

1.0

(195) 

(625) 

(4,408) 

(12, 588) 

(19, 421) 

(3,810)

Totals and weighted 

averages........... 15,333,800 0.22 0.15 (700,156) 4.8 (223,545) 7,307,081 0.21 0.13 (2,084,469) 0.9 (2,346,494) 384,169 0.22 0.11 (47,8'7) 0.6 (41,047)

Shiprock district Chuska district Other districts and areas

Tons

Grade (weight percent)

U3 08 CaCOa 2

Tons

Grade (weight percent)

U3 08 V205 3 CaCOs 5

Tons

Grade (weigh* percent)

U3 08 CaCOs 2

1950 . 

1961 .

1962. -..

1953... - ..

1954..- --.

1955. .--...

1956.. ..--.

1957. .. ..

1958- . .

1959 .--...

I960 -.

1961- ....

1962.. .....

1963 ..

1964. . .....

... ... ... 5,803

 . 232

 --.. 5,374

.--.--. 3,285

..---.. 3,868

 1,656

.... . 1,195

. 719

480

.------ 82

. 480

.--.-. 136

.. .... 1,718

. 1,303

..-.--.- 726

0 21

,18

32

.25

23

25

22

.20

21

37

,22

22

20

.12

2.24

2.38

3.12

2.71

3.17

2.44

1.98

1.55

9 17

1.26

1.98

1.49

(5,803). .

/OOO^

(5,374) _

(3,285) 

(3, 868) 7. 7

(1,656) 11.5

(1,195) 10.0

(719) 7. 6

(480) 7 9

/oo(

(480)

(136)

fl nfl\

(591) 

a

QOQ\

(1,634)

(920)

(698)..

1,866

4,014

1

OOO

937

1,955

444

4 06°

4,214

3,996

0.12 1

2Q

99

1Q

10

.17 .

22

.21

00

.20 .

11 15

23

.17

21

16

12

12

(1,628) . 

(1, 866) 3. 6

(4, 014) 3. 7

(937) 5. 7

(1, 955) 3. 7

(4,062) .

(4,214) 

(415)..

(3, 599)

(1, 832)

(9371

(1, 955)

112

590

2,945

6,652

239

322

127

74

1,801

5,490

2,122

0.22

.19

.21

.37

.18

.14

.14

.18

.16

.14

.14

0.12

.12

.03

.06

1.29

(fi")

(57)

(2, 446)

(4, 78?)

(13).

6 5

11.9

1 6

1.2

2 0

(90)

(57)

(592)

(6, 556)

(239)

Totals and weighted 

averages____... 6 27,057 0.24 2.56 (24,027) 9.2 (5,286) 26,513 0.19 0.15 (20,508) 4.3 (8,738) 20,474 0.23 0.05 (7.39P) 1.4 (7,534

1 Numbers in parentheses are tons of sandstone and limestone ores assayed for 

VjOs.

2 Numbers in parentheses are tons of sandstone ore assayed for CaCCb.

3 Numbers in parentheses are tons of sandstone ore assayed for VjOs.

* Numbers in parentheses are tons of sandstone and carbonaceous shale ores assayed

5 Numbers in parentheses are tons of sandstone and carbonaceous shale ores assayed 

for CaCOa.

6 Prior to 1950, and principally during World War II, about 10,000 tons of ore was 

produced from the Eastside Lease, Vanadium Corp. of America. I Tost of this ore, 

however, came from Arizona; it averaged about 0.30 percent UsOg and 2.50 percent 

VaOs and during 1942-43 was mined for vanadium only.

Of a total of about 10,000 tons mined from the Eastside 

Lease, Vanadium Corp. of America, about 9,000 tons 

was mined during 1942-43 for vanadium only and 

about 1,000 tons was mined in 1948 for uranium and 

vanadium. Most of this output, however, came from 

Arizona; it averaged about 0.30 percent U3O8 and 2.50 

percent V2O5.

The Chuska district started production in 1952, and 

by the end of 1964 had yielded about 26,500 tons of ore 

having an average grade of 0.19 percent U3O8 and 0.15 

percent V2O5 (table 2). This output came from 15 

mines and was ore from sandstone. Assays of about 

8,700 tons mined during the 1953-58 period averaged 

about 4 percent lime.

In addition to the ore mined from the above-mentioned districts, about 20,500 tons was mined from 

other scattered districts and areas during the 1954-64 

period. This ore, which averaged 0.23 percent U3OS

(table 2), was principally in sandstone ard volcanic 

rocks; some was in limestone, and a small amount was 

in coaly shale. These ores were low in vanadium except 

for a 13-ton shipment of sandstone ore which was 

reported to have averaged 1.29 percent V2O5. During 

the 1954-57 period, about 7,400 tons of the sandstone 

ores had an average content of 0.05 percent V2O5 . The 

lime content of the sandstone ores varied rather widely 

between deposits, as would be expected for the relatively small and spotty occurrences. During the 1954- 

58 period, the lime content ranged from about 1 to 12 

percent and averaged about 1.5 percent.

The ores in northwestern New Mexico occur in sandstone, limestone, carbonaceous shale and coal, and in 

igneous rock in rocks that range in age from Pennsylvanian to Tertiary. Ores that occur in sandstone are 

the most economically important, constituting more 

than 95 percent of the tonnage yielded from 1950 to
GEOLOGIC SETTING

194 (table 3). Ores in limestone are second in importance, having yielded about 4 percent of the total; ores in 

carbonaceous shale and coal, and in igneous rocks, constitute less than 1 percent of the total.

The uranium: vanadium ratio of the ores generally 

is about the same regardless of the grade, type, or age 

of host rock. Where the average grades show marked 

differences from the general averages, the tonnage is 

small and the differences are probably not significant.

At the end of 1958, most of the uranium ores from 

northwestern New Mexico were being processed by six 

mills which had a total rated capacity of 11,075 tons 

per day 2 . At the end of 1964, through a property merger 

and the closure of one mill, the following mills were 

operating; they had a collective rated capacity of 

9,000-10,000 tons per day:

Company Location

Vanadium Corp. of America_________. Shiprock.

Homestake-Sapin Partners__________ Grants.

Kermac Nuclear Fuels Corp_________ Grants.

The Anaconda Co ________. Bluewater.

GEOLOGIC SETTING

The three physiographic units, or provinces, in 

northwestern New Mexico are marked by structural 

and lithologic as well as physiographic characteristics 

(fig. 1). The northern part of the area in the Colorado 

Plateaus province is a broad structural as well as topographic depression, the San Juan Basin. It is characterized by a sedimentary fill of marine and continental 

rocks that totals several thousand feet in thickness and 

ranges from Paleozoic to Quaternary in age. Locally 

around the margins of the basin there are intrusive igneous rocks of Tertiary and Quaternary ages. The 

southern part of the province, the Datil volcanic field,

2 U.S. Atomic Energy Commission press release 222, Feb. 1, 1959, 

Grand Junction, Colo.

is characterized by an extensive covering of lavas r.nd 

associated continental sedimentary rocks that totals 

several thousand feet in thickness. These rocks are 

mostly Tertiary and Quaternary in age and cover older 

marine and continental sedimentary rocks which are 

exposed along the east and north margins of the ar^a.

The part of the area in the Southern Rocky Mo^ntains province consists generally of mountain blocks 

that have Precambrian cores; these blocks are draped by 

marine and continental sedimentary rocks, mostly of 

late Paleozoic and Mesozoic ages, that are several thousand feet thick, and by valley fills and local volcanic 

piles of Tertiary and Quaternary ages that also are 

several thousand feet thick.

The part of the area in the Basin and Range province is characterized by northward-trending faultblock mountains and intervening basins. Along the 

western part of the province and extending northward into the Southern Eocky Mountains province, is 

the Rio Grande trough, a structural depression. It is 

filled by several thousand feet of continental sedimentary and volcanic rocks of late Tertiary and Q laternary ages. East of the Rio Grande, the fault-block 

mountains are generally underlain by crystalline ro",ks 

of Precambrian age which are capped by eastward-dipping marine and continental sedimentary rocks of l<\te 

Paleozoic and Mesozoic ages and by continental sedimentary rocks of Tertiary and Quaternary ages. 

These rocks total several thousand feet in thickness. 

At the north end of the province the early Tertiary 

and older rocks are intruded by laccolithic masses of 

early Tertiary age.

STRATIGRAPHY

The lithology, thickness, areal distribution, r,nd 

stratigraphic relations of the uranium-bearing and asTABLB 3. Uranium ores produced from northwestern New Mexico, classified by age and type of host rock, 1950-64

Age

Tertiary. .

Cretaceous

Jurassic.. _________

Permian

Pennsylvanian _

Host rock

Type

Sandstone _____

Sandstone __ __ _

Carbonaceous shale and 

coal.

Limestone

Limestone and sandstone. 

Sandstone

Limestone

Percent of 

Tons of ore total 

tonnage

9,285 

9,036 

57, 791 

6,497

22, 035, 186 

975, 497 

4, 513 

67 

1,039 

183

0. 1 

. 1 

. 3 

. 1

95.4 

4.2 

. 1 

. 1 

. 1 

. 1

U3 08 V2 06 » 

(weight (weight percent) 

percent)

0. 14 0 

.33 

. 23 

. 20

.22 

. 22 

. 34 

. 14 

. 21 

. 12

04 

03 

11 

03

13 

14 

16 

13 

38 

10

(68) 

(6, 877) 

(43, 920) 

(4, 438)

3 (2,364, 101) 

(444, 965) 

(999) 

(67) 

(803) 

(183)

11.

1

1. 

80. 

42. 

14. 

51. 

11.

CaCOs 2

(weight percent)

3 

2 

6

7

2 

5 

2 

0

7 

7

(97) 

(6, 995) 

(40, 273) 

(2,434)

(2, 578, 929) 

(413, 325) 

(1,848) 

(59)

(727) 

* (183)

Total or weighted average._______________ 23, 099, 094 100.6 0.22 5 0. 13 5 (2, 414, 965) 5 1. 2 s (2, 626, 256)

1 Numbers in parentheses are tons of ore assayed for VaOj. * Probably silicifled as well as sandy.

2 Numbers in parentheses are tons of ore assayed for CaCCb. 5 Only the ores in sandstone are reported. 

* Excludes tonnage for Shiprock district, which for 24,027 tons averaged 2.56 percent V.Os.
10 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

sociated formational units are described to provide 

the setting for the uranium deposits, which occur in 

about 30 formational units. The units which contain 

the more economically important uranium deposits, or 

which have the greatest potential for containing them, 

are described in more detail than others. Some relatively unimportant units are combined for brevity or 

are omitted. The outcrops of most of the exposed 

stratigraphic units are shown on plate 1, and the general stratigraphic relations of the principal units, including those in the subsurface, are shown on the 

correlation chart, plate 2.

ROCKS OF PRECAMBRIAN AGE

The oldest rocks exposed in northwestern New Mexico are Precambrian and crop out in the Zuni Mountains, in the flanks of the ranges along the Rio Grande, 

in the Sierra Nacimiento, in the San Pedro Mountains, 

and in the ranges in the eastern part of Rio Arriba 

County (pi. 1). These rocks consist mostly of quartzite, 

schist, slate, granite, rhyolite, and andesite, and include 

local pegmatite bodies and quartz veins. The exposed 

thickness of the Precambrian rocks is unknown, but 

probably is many thousands of feet.

OBTEGA QUABTZITE OF JUST (1937) AND 

ASSOCIATED BOCKS

In the vicinity of Petaca, eastern Rio Arriba County, where some uranium deposits occur, Just (1937) 

has subdivided the Precambrian rocks into the (older) 

Hopewell Series and (younger) Ortega Quartzite and 

included Petaca Schist. The Hopewell and Ortega intertongue with the Picuris Basalts and Vallecitos Rhyolites. All the Precambrian formations were intruded by 

the Tusas Granite. The Hopewell Series and Ortega 

Quartzite are mostly sedimentary in origin.

ROCKS OF CAMBRIAN(?) AGE

Unexposed and unnamed rocks, tentatively considered as Middle or Late Cambrian in age, occur under 

the San Juan Basin in northwestern San Juan County. 

These rocks, which consist of conglomeratic sandstone 

and shale, range in thickness from 0 to about 100 feet, 

resit on the Precambrian basement, and are considered to 

be near-shore marine in origin (Bass, 1944; Baars and 

Knight, 1957; Strobell, 1958). They apparently pinch 

out southeastward and thicken northwestward into 

Colorado, Utah, and Arizona. These rocks have been 

tentatively correlated lithologically with the Tapeats 

Sandstone of northern Arizona and the Ignacio Quartzite of southwestern Colorado, which generally are considered to be Early and Middle 'Cambrian in age, and 

Late Cambrian in age, respectively.

ROCKS OF DEVONIAN AGE

Unexposed rocks of Late Devonian age occur under the San Juan Basin in northwestern San Juan 

County (Bass, 1944; Baars and Knight, 1957; Strobell, 

1958). They thin southeastward and probably pinch 

out between the Precambrian basement and overlying 

rocks of Mississippian or younger age. Eastward, 

these unexposed rocks may extend und«.r the San 

Juan Basin, because correlative thin rock? occur east 

of the area in the Sangre de Cristo Mountains where 

they rest on the Precambrian basement (Baltz and 

Read, 1960). Northwestward, the Devonian rocks 

thicken into southwestern Colorado, southeastern Utah, 

'and northeastern Arizona, where they overlie unnamed 

rocks of Oambrian(?) age. The Devonian rocks are 

considered to 'be extensions of the Elbert Formation 

and overlying Ouray Limestone of southwestern 

Colorado.

ELBEBT FOBMATION

The Elbert Formation (Cross, 1904) in northwestern New Mexico consists mostly of black, green, and 

maroon shale, glauconitic sandstone, and some limestone and sandy dolomite. Some of the lijpestone-dolomite units are as much as 100 feet thick, and are 

fairly uniform carbonates. The Elbert rang<^s from 300 

to 750 feet in thickness and is considered to be a nearshore marine and littoral deposit (Strobell, 1958).

ROCKS OF MISSISSIPPIAN AGE

Rocks of Mississippian age are the oldest exposed 

rocks of Paleozoic age in northwestern New Mexico. 

They crop out locally along the flanks of tH lower Rio 

Grande Valley and in the San Pedro Mo^mtains and 

the Sierra Nacimiento, where they rest on the Precambrian basement. In the subsurface in the northwestern 

part of the San Juan Basin they rest on rocks of Devonian age. The Mississippian rocks, fron oldest to 

youngest, consist of the Leadville Limestone, Caloso 

Formation of Kelley and Silver (1952), Kelly Limestone, and the Arroyo Penasco Formation.

LEADVILLE LIMESTONE

The Leadville Limestone (Emmons and others, 1893; 

Kirk, 1931) overlies the Ouray Limestone (Spencer, 

1900; Kirk, 1931) in northwestern New Mexico, but 

is lithologically similar to and difficult to differentiate from it (Strobell, 1958). Rocks of Leadville age are 

of unknown extent southward under the San Juan 

Basin, but they may extend eastward under the northern part of the basin, for the reason that tl 3y correlate
STRATIGRAPHY 11

with relatively thin rocks of the same age in the Sangre 

de Cristo Mountains (Baltz and Bead, 1960).

CALOSO FORMATION OF KELLEY AND SILVER (1952), 

KELLY LIMESTONE, AND ARROYO PENASCO FORMATION

The Oaloso Formation crops out on the south flank 

of the Ladron Mountains (Kelley and Silver, 1952) 

and along the flanks of the lower Eio Grande Valley 

near Socorro (Armstrong, 1958,1959). The Caloso generally consists of a thin basal sandstone and shale unit 

and an overlying unit of cherty algal limestone. It 

ranges in thickness from 0 to about 50 feet and rests on 

the Precambrian basement.

The Kelly Limestone crops out in the Magdalena 

and Lemitar Mountains (Herrick, 1904; Gordon, 1907a; 

Lindgren and others, 1910; Loughlin and Koschmann, 

1942) and, according to Armstrong (1958,1959), in the 

Ladron Mountains. The Kelly is a gray medium-bedded cherty limestone that contains a medial unit of 

dolomitic limestone and shale. The Kelly Limestone 

ranges in thickness from 0 to about 75 feet; it generally rests 011 the Precambrian basement, but locally in 

the Ladron Mountains it rests on the Caloso Formation (Armstrong, 1958, 1959).

The Arroyo Penasco Formation crops out in the San 

Pedro Mountains, in the Sierra Nacimiento (Fitzsimmons and others, 1956), and in the Sandia and Manzano Mountains (Armstrong, 1958, 1959). It consists 

of light-gray thin-bedded to massive fine-grained 

somewhat cherty limestone; it ranges in thickness 

from 0 to about 150 feet and rests on the Precambrian 

basement.

ROCKS OF PENNSYLVANIA AGE

Eocks of Pennsylvania!! 'age consist of the Molas, 

Hermosa, and Rico (part) Formations, which occur 

only in the subsurface in northwestern San Juan 

County; of the Sandia Formation and Madera Limestone of the Magdalena Group, rather widespread 

units in the southeastern part of the area; and of unnamed sandstone and siltstone in northeastern Rio 

Arriba County. These rocks are mostly marine, but 

they grade into near-shore continental f acies around the 

flanks of the Zuni and Chuska Mountains in the northeastern part of the San Juan Basin.

MOLAS, HERMOSA, AND LOWER PART OF RICO 

FORMATIONS

Unexposed rocks of Pennsylvania!! age in northwestern San Juan County are about 1,500 feet thick, 

rest on the Leadville and Ouray Limestones, and consists of, from base to top, the Molas, Hermosa, and

329-381 O 69 2

Rico (part) Formations. The description that follows 

is taken mostly from Strobell (1958).

The Molas Formation (Cross and others, 1905) in 

northwestern New Mexico is a marginal marine-continental sequence that consists of dark-red, purple, and 

gray shale, sandy shale, and sandstone, and, in the upper part, some marine limestone. The Molas range? in 

thickness from 60 to 175 feet.

The Hermosa Formation (Cross and Spencer, If 00; 

Roth, 1934) is mostly marine, and consists of limestone, dolomite, and gray shale, but in the northwest 

corner of the area it contains evaporate salt beds in the 

middle part of the formation. The Hermosa is about 

1,000-1,350 feet thick.

The Rico Formation (Cross and Spencer, 1900) is a 

transitional unit between the marine Hermosa Formation and the overlying continental Permian Cutler 

Formation (Cross and others, 1905). The Rico consists 

of varicolored shale and siltstone, and some interbedded marine limestone in the lower part, and ranges 

in thickness from about 350 to 475 feet.

SANDIA FORMATION

Oldest of the Pennsylvanian rocks in the southeast 

em part of the area is the Sandia Formation, lower 

formation of the Magdalena Group (Herrick, 1900; 

Gordon, 1907b). It crops out in the ranges along both 

sides of the Rio Grande Valley as far north as the San 

Pedro Mountains. It generally ranges in thickness from 

about 100 to 600 feet, consists of dark shale and subordinate amounts of earthy limestone, sandstone, and 

quartzite, and rests on rocks of Mississippian and Precambrian ages (Loughlin and Koschmann, 1942; Fead 

and others, 1944; Kelley and Wood, 1946; Wilpolt and 

others, 1946; Wilpolt and Wanek, 1951; Wood and 

others, 1946; Armstrong, 1959).

MADERA LIMESTONE

The Madera Limestone, middle formation of the 

Magdalena Group (Keyes, 1905; Gordon, 1907b), overlies the Sandia Formation, except locally in the Sandia 

Mountains (Read and others, 1944), hi the northern 

part of the Sierra Nacimiento, and in the San Pedro 

Mountains, where it rests on Precambrian rocks (Wood 

and others, 1946). Rocks equivalent in age to the Madera and possibly in part to the Sandia Formation extend westward under cover into the Datil volcanic field 

and northward under the San Juan Basin and pinch 

out around the flanks of the Zuni and Chuska Mountains (Armstrong, 1959; Baars and Knight, 1957).

In most places the Madera consists of two members: 

A lower cherty gray limestone with minor interbeds 

of sandstone and siltstone and an upper member of
12 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

interbedded arkosic sandstone, siltstone, and some 

cherty gray limestone (Loughlin and Koschmann, 

1942; Read and others, 1944; Kelley and Wood, 1946; 

Wilpolt and others, 1946; Wilpolt and Wanek, 1951; 

Wood and others, 1946). The thickness of the Madera 

generally ranges from about 500 to 1,000 feet; it is 

about 1,850 feet thick in the Lucero Mesa area (Kelley 

and Wood, 1946), whereas it is only 80 feet thick in the 

La Joyita Hills where the upper member is absent 

(Wilpolt and others, 1946). In the Nacimiento-San 

Pedro Mountains area the lower limestone member is 

missing and the upper arkosic member rests on the 

Precambrian basement.

SANDSTONE AND SILTSTONE

Muehlberger (1957) described a local occurrence of 

Pennsylvania rocks in northeastern Rio Arriba 

County; these rocks are about 250 feet thick and consist of red arkosic sandstone, siltstone, and some nodular fossiliferous limestone. These rocks, which apparently wedge out eastward against Precambrian 

quartzite, probably represent intertonguing continental 

and marine debris near the northeast 'margin of the 

Pennsylvanian embayment. The finer grained, thinbedded, and calcareous material may represent or be 

partly equivalent to the upper arkosic member of the 

Madera Limestone, which crops out along the north 

flank of the San Pedro Mountains (Wood and others, 

1946). The coarser arkosic sandstone units, which are 

as much as 60 feet thick, thin northeastward and presumably thicken under cover to the southeast. Their 

areal extent is not known, but it is rather limited. 

Pemisylvanian rocks are missing to the northwest and 

along the west side of the Chama Basin (Muehlberger, 

1957), and the arkosic units would be expected to 

become finer grained and thinner bedded southward 

away from the source area.

ROCKS OF PERMIAN AGE

Rocks of Permian age crop out extensively in the 

ranges and mesas east of the Rio Grande, and in the Lucero Mesa area, Zuni and San Pedro Mountains, Sierra 

Nacimiento, southern part of the Chama Basin, and 

in a small area on the eastern flank of the Chuska 

Mountains. The Permian rocks have a maximum 

thickness of about 2,500 feet in the Lucero Mesa area 

(Kelley and Wood, 1946) 'and are about 1,000-1,500 feet 

thick in the San Pedro Mountains and the Sierra Nacimiento (Wood and others, 1946), Zuni and Chuska 

Mountains (Baker and Reeside, 1929, p. 1426), and in 

the area east of the Rio Grande (Read and others,

1944; Wilpolt and others, 1946; Wilpolt and Wanek, 

1951).

In the southern part of the area, from tl °, base upward, the Permian rocks range from the kcal marine 

Bursum Formation into the continental clastic sedimentary rocks of the Abo and Cutler Formations, 

through gradational continental and marine clastic and 

evaporite beds of the Yeso Formation arH Glorieta 

Sandstone, to the clominaiitly marine beds of the uppermost part of the San Andres Limestone and the 

Bernal Formation. In the northern part cf the area 

the rocks are almost entirely continental ?,nd consist 

of the upper part, of the Rico Formation (see above) 

and the overlying Cutler Formation.

BURSUM FORMATION

The Bursum Formation crops out in the southeastern part of the area east of the Rio Grande where it 

rests on the Madera Limestone and is the upper formation of the Magdalena Group. It consists of purplered and green shale separated by thin beds of arkose, 

arkosic conglomerate, and gray limestone; it ranges 

in thickness from 0 to 250 feet (Wilpolt and others, 

1946; Wilpolt and Wanek, 1951).

ABO FORMATION

The Abo Formation (Lee and Girty, 1909, p. 12; 

Needham 'and Bates, 1943) crops out along the flanks 

of the Rio Grande Valley and in the Sierra Nacimiento 

and the Zuni and Chuska Mountains It rests 

on the Madera Limestone and Bursum Formation 

along the flanks of the Rio Grande, and on Precambrian rocks in most of the Zuni and Chuska Mountains 

and in the central part of the Sierra Nacimiento. North 

of lat 36°N., equivalents of the Abo Formation are 

arbitrarily included in the lower part of the Cutler 

Formation (Wood and others, 1946).

The Abo Formation ranges in thickness from about 

300 to 900 feet and is composed mostly of darkred and gray siltstone and dark-red and locally gray 

arkosic sandstone. The sandstone units are generally 

very lenticular, crossbedded, locally contain plant debris or impressions, and range in thickness from a few 

inches to as much as 75 feet (Read and others, 1944; 

Kelley and Wood, 1946; Wood and others, 1946; Wilpolt and others, 1946; Wilpolt and Wanek, 1951). The 

principal source areas for the Abo were tli?- ancestral 

Zuni highlands on the west, and Joyita highlands to 

the south, the Pedernal highland to the east, and the 

San Luis-Uncompahgre highland to the nor+h. (McKee 

and others, 1967).
STRATIGRAPHY 13

CUTLER FORMATION

The Cutler Formation (Cross and others, 1905) crops 

out in the central part of the Sierra Nacimiento, in the 

San Pedro Mountains (Wood and others, 1946), and 

on the east flank of the Chuska Mountains (O'Sullivan and Beaumont, 1957), where it rests 011 Precambrian rocks. North of lat 36°N. in the Sierra Nacimiento, equivalents of the Abo and the overlying 

Yeso Formations are arbitrarily included in the Cutler Formation (Wood and others, 1946). Northward 

from the San Pedro Mountains, the Cutler dips beneath younger rocks and is only partly exposed 

locally around the Chama Basin. In the Chuska Mountains only part of the De Chelly Sandstone Member of 

the Cutler Formation is exposed (Baker and Reeside, 1929; O'Sullivan and Beaumont, 1957). The Cutler ranges in thickness from about 500 to 1,000 feet 

in the Sierra Nacimiento-San Pedro Mountains area 

(Wood and others, 1946) and probably is about 1,000 

feet thick along the flanks of the Chuska Mountains 

(Baker and Reeside, 1929, p. 1426; Alien and Balk, 

1954, p. 63-65).

The Cutler Formation generally is similar lithologically to the Abo, but some of the sandstone units are 

thicker, being as much as 125 feet thick (Wood 

and others, 1946). The De Chelly Sandstone Member 

of the Cutler, in addition to being much thicker than 

sandstones in the Abo, is a light-red massive finegrained quartzose unit that has large-scale crossbeds. 

It is generally considered to be an eolian deposit 

(Gregory, 1917, p. 32-33; Alien and Balk, 1954, p. 

63.)

YESO FORMATION AND GLORIETA SANDSTONE

The Yeso Formation and the Glorieta Sandstone 

successively overlie the Abo Formation and crop 

out along the margins of the Rio Grande Valley (Read 

and others, 1944; Kelley and Wood, 1946; Wilpolt and 

others, 1946; Wilpolt and Wanek, 1951) and Zimi 

Mountains (Read,, 1951, p. 83) and in the Sierra 

Nacimiento (Wood and others, 1946).

The Yeso Formation (Lee and Girty, 1909; Needham and Bates, 1943), is mostly an orange-red sequence of massive or crossbedcled quartzose sandstone 

vuid interbedded siltstone, limestone, and gypsum. It 

ranges in thickness from 0 to 1,700 feet.

The Glorieta Sandstone (Keyes, 1915; Needham 

and Bates, 1943; Baltz and Bachman, 1956) overlies 

the Yeso, is 0-200 feet thick, and is mostly a white 

quartzose cliff-forming sandstone.

SAN ANDRES LIMESTONE

The San Andres Limestone (Lee and Girty, 1909; 

Needham and Bates, 1943), which rests on the Glorieta Sandstone, crops out in the ranges along the flanks 

of the Rio Grande trough and in the Zuni Mountrlns 

and southern part of the Sierra Nacimiento. It hrs a 

maximum thickness of about 450 feet at Lucero Mesa 

(Kelley and Wood, 1946), is about 400 feet thick east 

of the Rio Grande (Wilpolt and Wanek, 1951), 100- 

140 feet thick in the Zuni Mountains (Smith, 1954), 

and about 50 feet thick in the southern part of the 

Sierra Nacimiento (Wood and others, 1946).

The San Andres is mostly gray cherty limestone 

and interbedded gray shale, sandstone, and gypsum. 

The limestone units range in thickness from a few 

feet to more than 100 feet and are concentrated in different parts of the formation in different areas. East 

of the Rio Grande the limestone is mainly in the lower part (Read and others, 1944; Wilpolt and others, 

1946; Wilpolt and Wanek, 1951), at Lucero Mesa in the 

upper part (Kelley and Wood, 1946), and in the Zuni 

Mountains it constitutes the entire formation except 

for a thin sandstone unit near the middle (Smith, 

1954). In the southern part of the Sierra Nacimiento, 

however, the San Andres is mostly an orange-red 

siltstone, and only a thin wedge of limestone occurs 

at the base (Wood and others, 1946).

BERNAL FORMATION

The Bernal Formation (Bachman, 1953) overlies the 

San Andres Limestone and crops out in the ranges along 

the east side of the Rio Grande. The Bernal is mostly 

an orange-red silty sandstone that contains local thin 

beds of dark-gray limestone and that ranges in thickness from 5 to about 50 feet (Read and others, 1£44; 

Wilpolt and others , 1946; Wilpolt and Wanek, 1951).

ROCKS OF TRIASSIC AGE

Rocks of Triassic age crop out along the margins of 

the San Juan Basin, southwest of the Zuni Mountains 

in the area near Zuni, in the San Pedro Mountains 

and in the Sierra Nacimiento, around the peripHry 

of the Chama Basin, and along the flanks of the Rio 

Grande Valley. These rocks are about 1,500-2,000 feet 

thick along the west and south sides of the San Juan 

Basin (Strobell, 1956; Alien and Balk, 1954; Sirith, 

1954) and southwest of the Zuni Mountains (Akers 

and others, 1958), but they generally thin eastward 

and probably thin southward. They are about 1,000 feet 

thick in the Sierra Nacimiento and in the San Pedro
14 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

Mountains but thin to about 600 feet in the southeastern part of the Chama Basin (J. H . Stewart, written oommun., 1958) and to about 400 feet in the northeastern part of the Chama Basin (Dane, 1948). South 

of the San Juan Basin in the vicinity of Lucero Mesa 

the Triassic rocks are about 1,000 feet thick (Kelley and 

Wood, 1946), but east of the Eio Grande they are about 

500 feet (Wilpolt and others, 1946). Southward from 

the San Juan Basin they probably thin, but how much 

is uncertain because of incomplete exposures and 

beveling by pre-Dakota erosion (Silver, 1948).

The Triassic rocks consist of brick-red, maroon, and 

gray siltstone, some shale and arkosic sandstone, and 

local limestone-conglomerate lenses.

Only a few relatively unimportant uranium deposits 

are known in the Triassic rocks of northwestern New 

Mexico, but these rocks will be described in some detail because they contain stratigraphic equivalents of 

lithologically similar rocks in northeastern Arizona 

and southeastern Utah that contain important uranium deposits.

Along the west and south sides of the San Juan Basin and southwest of the Zuni Mountains the Triassic 

rocks, in ascending order, are composed of the Moenkopi(?) Formation, the Chinle Formation, and the 

Wingate Sandstone.

MOENKOPI (?) FORMATION

The Moenkopi Formation, which is widespread in 

Arizona, possibly has a limited distribution in New 

Mexico (McKee, 1954, p. 5-7). It may crop out along 

the flanks of the Zuni Mountains and can be traced 

eastward, questionably, at least as far as Lucero Mesa 

(J. H. Stewart, written commun., 1958). In New Mexico, the Moenkopi (?) consists of lenses of pale-red 

locally conglomeratic sandstone and interstratified 

gray and red siltstone. It rests on the San Andres 

Limestone and ranges in thickness from 0 to about 

200 feet (J. H. Stewart, written commun., 1958).

CHINLE FORMATION

Most of the Triassic rocks in northwestern New Mexico are constituted by the Chinle Formation which has 

the same general outcrop distribution as that of the 

Triassic rocks, except east of the Eio Grande where 

the Triassic rocks are represented by the Dockum 

Formation.

For convenience of description the Chinle Formation 

is discussed by general areas along (1) the west and 

south sides of the San Juan Basin and (2) the east 

side of the San Juan Basin.

WEST AND SOUTH SIDES OF THE SAN JTTA1T BASIN

Along the west side of the San Juan Basin the 

Chinle Formation unconformably overlie the De 

Chelly Sandstone Member of the Cutler Formation and 

along the south side unconformably overlies the 

Moenkopi (?) Formation. Along the Arirona border 

the Chinle is about 1,200-1,600 feet thicl: and comprises, in ascending order, the Shinarrimp Member (0-100 ft. thick), lower red member (50-400 ft. 

thick), Petrified Forest Member (1,000-1,500 ft. thick), 

and the Owl Bock Member (0-500 ft. thhk) (Akers 

and others, 1958; Strobell, 1956). These members as a 

whole consist of red, brown, purple, and g^ay varicolored bentonitic silty claystone and siltstone but contain some lenses of sandstone and lime-pebble and 

chert-pebble conglomerate.

Of the several members of the Chinle Formation that 

are present along the Arizona border, only the Shinarump Member, lower red member, and the Petrified 

Forest Member extend appreciably into northwestern 

New Mexico and justify description.

SHINABUMP MEMBER

Inasmuch as the Shinarump Member (Stewart, 1957) 

is the host for important uranium deposits in northeastern Arizona and southeastern Utah (F: nch, 1959), 

its characteristics and extent in northwestern New 

Mexico are described in some detail. The description of 

the Shinarump including its extent in New Mexico, 

is based almost entirely on exposures in Arizona and 

Utah.

The Shinarump Member, which is present in much 

of southern Utah and northern Arizona (Gregory, 

1917, p. 38; Akers and others, 1958, p. 90, f g. 2; Stewart and others, 1959, p. 504), ranges in thickness 

from 0 to 250 feet. In Monument Valley, Ariz., it is 

predominantly gray to buff conglomeratic sandstone 

(Witkind, 1956, p. 102-103) 50-100 feet thick. 

The pebbles are well rounded, range in diameter from 

granule size to 2 inches, and are composed of quartz, 

quartzite, and chert. The fact that the peblxl «s are in a 

quartz-sand matrix cemented by silica, c^lcite, clay, 

and iron oxide makes the Shinarump fair'y resistant. 

Both the conglomerate and sandstone beds are lenticular and crossbedded. Plant fragments are fairly common and range in size from fine debris to logs as much 

as 4-5 feet in diameter and 50 feet in length. Much of 

the plant material is silicified, but some is degraded to 

black carbonaceous material. Lenses of claystone are 

common in the upper parts of the unit but uncommon elsewhere.

Uranium ore bodies are localized in the conglomeratic standstone where it fills stream channel^ scoured in
STRATIGRAPHY 15

the underlying Moenkopi Formation. These channels 

range from about 15 feet in width and 10 feet in 

depth to 2,300 feet in width and 70 feet in depth 

(Witkind, 1956, p. 114).

In the Carrizo Mountains and Fort Defiance 

areas, Arizona, near the New Mexico border, the Shinarump Member is similar in thickness and lithology 

to the Shinarump in Monument Valley, Ariz. In the 

Carrizo Mountains area, the thickness ranges from 

20 to 95 feet, but plant material is less common, and 

stream channels are not apparent (Strobell, 1956). Because the exposure in that area is small and is probably near the northeast limit of the member (Stewart 

and others, 1959, p. 506, fig. 74), it may not be typical 

of the unit in this area. Near Fort Defiance, southwest 

of the Chuska Mountains, the Shinarump ranges in 

thickness from 0 to 35 feet, contains some silicified 

plant fragments, and is partly composed of streamfilled channels 30-50 feet wide and 5-10 feet deep 

(Alien and Balk, 1954, p. 65-67).

Akers, Cooley, and Repenning (1958, p. 90) show the 

Shinarump Member at Zuni, southwest of the Zuni 

Mountains, and extend it into New Mexico as far 

east as Thoreau but indicate, that it is thin and discontinuous. East of Zuni, however, it is mostly covered and its eastward extent is uncertain, although 

J. H. Stewart (written commun., 1958) observed a 

remnant above questionable Moenkopi on the west side 

of Lucero Mesa which had a lithology similar to the 

Shinarump Member in Arizona,

The thin and discontinuous exposures of the Shinarump east of Fort Wingate probably indicate that the 

outcrops are near the east margin of the member. 

Available information, therefore, suggests that in 

New Mexico the east margin of the Shinarump extends from near the northwest corner of New Mexico 

southeastward to the Rio Grande in the vicinity of Lucero Mesa. Southwestward from this margin the extent of the Shinarump in New Mexico is speculative 

because it is discontinuous and generally buried under younger rocks and, south of the San Juan Basin, an 

unknown amount of it has been removed by pre-Dakota erosion. Because of its fluvial structures, lithology, relative thinness, wide extent, and the uncomformable nature of the contact with the Moenkopi, the 

Shinarump is most likely a pediment deposit (Stokes, 

1950).

LOWER BED MEMBER

The lower red member of the Chinle Formation overlies the Shinarump Member, extends through the 

Zuni Mountains area, consists of mudstone, siltstone, 

and fine-grained sandstone, and is about 200 feet thick 

(Cooley, 1959).

PETRIFIED FOREST MEMBER AND INCLUDED SONSELA SANDSTONE BED

Of the several members of the Chinle Formation 

that are present along the Arizona border, only the 

Petrified Forest Member is widespread in northw°*stern New Mexico. It extends to the east side of the San 

Juan Basin, crops out along the south side of the basin, 

and may extend southward under the younger recks 

of the Datil volcanic field. It overlies the Shinarump Member, lower red member, or the Moenkopi (?) 

Formation in different parts of the area. From Hse 

to top the Petrified Forest Member generally consists 

of varicolored bentonitic claystone and siltstone in the 

lower part, the Sonsela Sandstone Bed in the micMle 

part, and red-brown claystone, siltstone, and some 

lenses of ledge-forming sandstone in the upper p^.rt. 

The following description of the Sonsela Sandstone 

Bed is mostly from Cooley (1959) and J. H. Stevrart 

(written commun., 1958).

The Sonsela Sandstone Bed crops out in the Zuni 

Mountains area and along the southwest margin of 

the San Juan Basin. It ranges in thickness from 50 to 

about 150 feet and consists of yellow-gray fine- to 

coarse-grained conglomeratic, cherty, and quartzose 

sandstone and some lenses of gray and red claystone. 

The bedding is mostly cross-stratified and in thir to 

thick trough-type sets. Conglomerate is present as 

thin lenses and as beds as much as 20 feet thick, 

which locally constitute much of the lower part of 

the unit. The pebbles, which are mostly chert and 

some quartzite and quartz, range from granule size to 

as much as several inches in diameter. The Sons^ela 

Sandstone Bed contains no known uranium deposits, but it is similar lithologically and in thickness to 

the Shinarump Member and to other uraniferous sandstone units of the Chinle Formation, and it had a similar southern source area (Cooley, 1959; Stewart and 

others, 1959, p. 523; Poole, 1961, fig. 199.1B). The £onsela, however, apparently contains less fossil plant debris, fewer well-developed channel scours, and more extensive mudstone and siltstone units than does the 

Shinarump Member.

EAST SIDE OF THE SAN JUAN BASIN

Along the east side of the San Juan Basin the 

Chinle Formation is exposed in the Sierra Nacimiento 

and in the San Pedro Mountains and along the margins of the Chama Basin (Wood and others, 1946). 

The Chinle rests on the Cutler Formation in the San 

Pedro Mountains area and on Precambrian rockr in 

most of the northern part of the Chama Basin (Dme, 

1948), but locally rests on sandstone and siltstone- of 

Pennsylvanian age (Muehlberger, 1957). South of lat 

36° N., the Chinle rests on the Abo Formation an<? on
16 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

the beveled edges of younger rocks of Permian age. 

East of the San Juan Basin the Chinle ranges in thickness from about 1,200 feet near San Ysidro to about 

400 feet in the northeastern part of the Chama Basin 

(Dane, 1948).

Wood, Northrup, and Cowan (1946) divided the 

Chinle Formation in the Sierra Nacimiento and San 

Pedro Mountains area, in ascending order, into the 

Agua Zarca Sandstone Member, Salitral Shale Tongue, 

Poleo Sandstone Lentil, and an unnamed shale, siltstone, and sandstone unit. In the same general area, 

J. H. Stewart (written commun., 1958) recognized five 

members namely, the Agua Zarca Sandstone Member, 

Salitral Shale Tongue, Poleo Sandstone Lentil, Petrified Forest Member, and an unnamed siltstone member and considered Wood, Northrop, and Cowan's 

(1946) shale, siltstone, and sandstone unit to be the 

Petrified Forest Member. Stewart extended his unnamed siltstone member, which occurs above the Petrified Forest Member, into the southeastern part of 

the Chama Basin and indicated that the unnamed 

siltstone member is probably equivalent to outcrops 

of the Chinle Formation in the northeastern part of 

the basin.

Except for the Agua Zarca Sandstone Member and 

the Poleo Sandstone Lentil, the Chinle Formation east 

of the San Juan Basin is a sequence of beds lithologically similar to the Petrified Forest Member along the 

west and south sides of the basin.

Although the Agua Zarca and Poleo contain few 

known uranium deposits, they are described in some 

detail because of their lithologic, stratigraphic, and 

structural similarity to the ore-bearing Shinarump 

and Moss Back Members in southeastern Utah.

AGUA ZARCA SANDSTONE MEMBEE AND POLEO SANDSTONE LENTIL

The Agua Zarca Sandstone Member and Poleo Sandstone Lentil were recognized by Wood, Northrop, and 

Cowan (1946) throughout much of the west and north 

flanks of the Sierra Nacimiento and San Pedro Mountains area where the two units are separated by the 

Salitral Shale Tongue which ranges from a wedge edge 

to 125 feet in thickness and which is lithologically 

similar to Wood, Northrop, and Cowan's (1946) siltstone member. In the southern Sierra NacimientoJemez Mountains area, Wood, Northrop, and Cowan 

(1946) indicated that the Poleo pinches out southward, 

and they recognized the Agua Zarca in the southern 

area only. J. H. Stewart (written commun., 1958), however, found that Wood, Northrop, and Cowan's Agua 

Zarca in the southern Sierra Nacimiento-Jemez Mountains area has characteristics more like those of the

Poleo Sandstone Lentil, and he believed that the Agua 

Zarca in the southern area either represerts a southward extension of the Poleo or is a segment of the Agua 

Zarca that was derived from the same general source 

area as the Poleo.

The Agua area and Poleo are each cliff-forming 

conglomeratic sandstone units that range in thickness 

from about 50 to 150 feet, but the thicknesses differ 

considerably from place to place, largely intertonguing and intergrading with the Salitral SI *\le Tongue 

and with the Petrified Forest Member a? recognized 

by Stewart (written commun., 1958). Each locally contains macerated and coalified plant debr;s and each 

contains generally small channel scours at the base. 

Although the two units resemble each othe^, they have 

the following rather distinctive features.

The Agua Zarca is generally varicolored and ranges 

from grayish red or purple to shades cf yellowish 

gray. It is characteristically coarse to very coarse 

grained; quartzite granules, pebbles, and cobbles are 

common, and chert pebbles occur locally. At the north 

end of the Sierra Nacimiento-Chama River canyon area 

the basal part of the Agua Zarca contains many quartzite boulders as much as a foot in diameter and, in the 

same area, some coarse-textured igneous rock cobbles 

and boulders. Also, in the general area, grain-size distribution and a southward to southwestward dominant 

dip direction of the cross-strata indicate that the Agua 

Zarca in this area was derived from the north and 

northeast, probably from the ancestral Rocky Mountains (F. G. Poole, written commun., 1961).

The Poleo is generally yellowish gray, fine to medium grained, and locally contains more siltstone units 

than does the Agua Zarca, and the conglomerate 

is composed of granules and pebbles of quartz, quartzite, chert, and rarely limestone or siltstone. Chert 

granules, which generally typify the Po!eo, increase 

in abundance northward whereas quartzite,, in contrast 

to that of the Agua Zarca, is a minor constituent (J. H. 

Stewart, written commun., 1958).

The Poleo and Agua Zarca occupy about the same 

stratigraphic position in the Chinle Formation as the 

Shinarump and Moss Back Members, but correlation with them as continuous units is speculative because of the distance between the respective exposures 

and because of the lack of subsurface information. 

Moreover, the projected east margin the Shinarump 

Member is about 40 miles or more west of the Poleo 

and Agua Zarca outcrops, so they are probr.bly not contiguous. Possibly the Agua Zarca is continuous with 

the Santa Rosa Sandstone southeast of the Rio Grande 

Valley and the Santa Rosa actually extends westward
STRATIGRAPHY 17

and is the unit identified as Shinarump in eastcentral New Mexico (McKee and others, 1959, p. 22, section B-B1 and fig. 25). The present assumption is that 

the Shinarump, Poleo, and Agua Zarca are separate 

units, which had a common southern source except for 

the part of the Agua Zarca in the northern Nacimientosoutheastern Chama Basin area, which had a northern 

or northeastern source.

DOCKUM FORMATION

East of the Rio Grande, rocks of Triassic age are 

represented by the Dockum Formation, which crops out 

locally along faults. The Dockum ranges in thickness 

from 80 to about 500 feet, includes equivalents of the 

Chinle Formation and possibly of the Moenkopi Formation, and consists of maroon and light-gray sandstone, siltstone, and shale and some local limestonepebble conglomerate lenses (Wilpolt and others, 1946; 

Wilpolt and Wanek, 1951; Read and others, 1944). 

Same sandstone units in the Dockum range in thickness 

from a few feet to as much as 50 feet and are similar 

lithologically to the Shinarump Member of the Chinle 

Formation.

WINGATE SANDSTONE

The Wingate Sandstone (Dutton, 1885, p. 136; Baker and others, 1947), is the only formation of the Glen 

Canyon Group (Gregory and Moore, 1931, p. 61) that 

extends appreciably into northwestern New Mexico. Although the Wingate Sandstone contains no known uranium deposits in New Mexico, is largely an eolian deposit as shown by its sweeping crossbeds, fineness, and 

uniformity of the sand grains, and is probably a poor 

host for uranium deposits, it is described to help distinguish it from the overlying Entrada Sandstone, 

a similar formation which is a host for some uranium 

deposits.

The Wingate rests on the Chinle Formation along 

the Arizona border, where it ranges in thickness 

from about 200 to 650 feet (Harshbarger and others, 

1957, p. 8-12, pi. 2). In that area it consists of a lower 

reddish-brown silty member and an upper reddishbrown massive cliff-forming sandstone member. The 

siltstone member grades into the Chinle and interfingers with the sandstone member along the west side 

of the San Juan Basin and southwest of the Zuni Mountains. The upper sandstone member thins eastward 

and either pinches out southeast of Laguna or is cut 

out under the Entrada Sandstone southwest of Laguna. 

Southward from the San Juan Basin the upper member 

of the Wingate thins and pinches out in southern 

Valencia County (Silver, 1948, p. 70). The relations of 

the upper member of the Wingate are discussed more

completely in another report (Hilpert, 1963, p. 8-9). 

The Wingate Sandstone also probably pinches out 

under the San Juan Basin because it is not recognized 

on the east side of the basin.

ROCKS OF JURASSIC AGE

Rocks of Jurassic age crop out in northwestern Few 

Mexico in approximately the same areas as the Triassic rocks. South of U.S. Highway 66, however, the 

Jurassic rocks were beveled progressively southward by 

pre-Dakota erosion and their southern limit is marked 

by a line that extends from about 30 miles south of Laguna westward into Arizona near Zuni (Silver, 1£48; 

Rapaport and others, 1952).

The Jurassic rocks consist of the San Raf ael Grc*ip, 

and the overlying Cow Springs and Zuni Sandstones, 

and the Morrison Formation, and total about 1,000 

feet in thickness. These units consist of orange, buff, 

and white eolian sandstone, red, buff, and gray fluvial, and some marine, sandstone and mudstone; varicolored lacustrine and fluvial claystone; and gray 

brackish-water limestone and gypsum.

The San Raf ael Group in northwestern New Merico 

consists of, in ascending order, the Carmel Formation, 

Entrada Sandstone, Todilto Limestone, Summerville 

Formation, and the Bluff Sandstone. The Carmel Formation pinches out a short distance southeast of the 

Four Corners (Harshbarger, and others, 1957) and 

deserves no further comment.

ENTRADA SANDSTONE

In northwestern New Mexico the Entrada Sandstone 

(Gilluly and Reeside, 1928, p. 76) generally is the basal 

formation of the San Rafael Group and the oldest formation of Jurassic age. It rests on the Wingate Sandstone in the western part of the area (Baker and 

others, 1947; Harshbarger and others, 1957), on the 

Chinle Formation in the eastern part (Wood and others, 

1946), and on the Dockum Formation east of the Rio 

Grande (Read and others, 1944; Wilpolt and others, 

1946; Wilpolt and Wanek, 1951). South of the ValemiaSocorro County line the Entrada is missing, partly the 

result of pre-Dakota beveling and partly because- of 

nondeposition (Silver, 1948).

In northeastern Arizona, adjacent parts of Utah, and 

northwestern New Mexico, Harshbarger, Repenriing, 

and Irwin (1957, p. 35-38) recognized three members a lower sandy member that is present only in 

Arizona and Utah, a medial silty member, and an 

upper sandy member. The medial silty member and an 

upper sandy member, as established at Fort Wingate, 

have been extended eastward into the Laguna district
18 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

(Harshbarger and others, 1957; Smith, 1954; Kapaport and others, 1952) and generally extend northeastward from Laguna into north-central New Mexico 

(D. D. Dickey, written commun., 1963). In most places 

the Entrada rests on the Wingate Sandstone, but at 

least in the southeastern part of the Laguna district it 

rests on the Chinle Formation (Kelly and Wood, 1946). 

Elsewhere in the Laguna district, rocks that have been 

called Wingate might belong in the Entrada. If they do, 

the Entrada rests on the Chinle throughout the district 

(Hilpert,1963,p.6-9).

The upper sandy member of the Entrada constitutes 

the thicker part of the formation and contains the 

known uranium deposits. It consists of reddish-orange to white fine-grained quartz sandstone and is 

marked by thick sets of large-scale crossbeds. It ranges 

in thickness from 80 to about 250 feet, and has a tendency to weather into bold rounded cliffs. The medial 

silty member, the lower unit in northwestern New 

Mexico, consists of red and gray siltstone and ranges 

in thickness from 10 to about 100 feet.

TODILTO LIMESTONE

The Todilto Limestone (Gregory, 1917, p. 55) rests 

on the Entrada Sandstone and has about the same 

outcrop pattern. Southward it pinches out along a line 

that is 10-20 miles south of U.S. Highway 66 (Kapapcrt and others, 1952). This line trends westward 

to a point south of Grants and then swings northwestward into Arizona west of Chuska Peak (pi. 1).

The Todilto Limestone consists of two units. The 

basal unit, which generally ranges in thickness from 

10 to 30 feet, consists of thin-bedded gray fine-grained 

limestone and some thin interbeds of siltstone and is 

present everywhere the Todilto crops out. The upper 

unit, which ranges in thickness from 0 to 100 feet, 

consists of anhydrite and gypsum and crops out along 

the east side of the San Juan Basin and northeast 

of the Sandia Mountains and extends under the central part of the basin. (See pi. 3.) Some of the debris 

in the Todilto consists of volcanic ash (Weeks and 

Truesdell, 1958). In some places the beds are nearly 

black, and some fine black carbonaceous material is 

concentrated locally along bedding planes. Wherever 

the limestone is pulverized it emits a fetid odor, and 

this characteristic coupled with the dark color, has led 

many to speak of the limestone as "petroliferous." 

Whether or not the limestone contains hydrocarbons 

and is petroliferous, its content of organic carbon is 

low, for it only locally contains as much as 1 percent 

organic carbon and in general averages only a few 

tenths of 1 percent. The relations of the organic carbon

to the uranium deposits is discussed under "Distribution of Elements in the Todilto Limestoue."

SUMMERVILLE FORMATION

The Summerville Formation (Gilluly and Keeside, 

1928, p. 79-80) overlies the Todilto Limestone and 

has about the same distribution pattern as the Todilto 

in northwestern New Mexico (J.S. Wright, oral commun., 1958). The Summerville ranges in thickness 

from 50 to about 225 feet and averages about 150 feet. 

It consists of reddish-brown and gray fine-grained 

sandstone and siltstone, whose individual unite range 

in thickness from a few inches to a few feet* South of 

Grants and south of Laguna, near its south margin, 

the Summerville contains a basal quartzitft-pebble conglomerate (Silver, 1948, p. 78; Hilpert, 1963, p. 12). 

The bedding is mostly parallel and probably represents near-shore deposition in a shallow marine embayment.

BLUFF SANDSTONE

Overlying the Summerville Formation is the 

Bluff Sandstone of the San Kafael Group (Gregory, 

1938, p. 58-59), which crops out along the west and 

south sides of the San Juan Basin (Harrhbarger and 

others, 1957, p. 42-43; Freeman and Hilpert, 1956). 

The Bluff Sandstone is a pale-orange or buff fine- to 

medium-grained crossbedded sandstone vhich weathers into bold rounded cliffs similar to those of the 

Entrada Sandstone, The Bluff ranges in thickness 

from about 50 feet in western San Juan County 

to about 300 feet in McKinley and Valencia Counties. In southwestern McKinley County the Bluff 

grades into the stratigraphically move extensive 

Cow Springs Sandstone (Harshbarger and others, 

1957, p. 48-51) which occupies the entire stratigraphic interval occupied elsewhere by the Todilto Limestone, Summerville Formation, Bluff Sandstone, and 

part of the overlying Morrison Formation. On plate 

1 these units are mapped with Zuni P^.ndstone in 

McKinley and Valencia Counties.

MORRISON FORMATION

The Morrison Formation (Cross, 189<*, p. 2; Emmons and others, 1896) is the most important host 

for uranium deposits in northwestern New Mexico. 

Its distribution is similar to the San Kafaol Group, 

and it originally covered most of the mapped area 

(pi. 1) and extended into northeastern Arizona, 

eastern Utah, and southwestern Colorado (Craig and 

others, 1955, fig. 19, p. 129). The former southern 

extent of the Morrison in New Mexico is not known 

because the beds were removed by erosion prior to 

the deposition of the overlying Dakota Sandstone
STRATIGRAPHY 19

(Silver, 1948). The southernmost outcrop of the Morrison is marked by a westward-trending line that 

is a few miles south of and parallel to U.S. Highway 

66.

The Morrison in northwestern New Mexico generally consists of gray, maroon, and buff mudstone, 

varicolored claystone, and gray to reddish-brown 

medium- to coarse-grained sandstone. The sandstone 

is arkosic, locally conglomeratic, and locally contains 

concentrations of carbonaceous material. The Morrison ranges in thickness from 400 to about 800 feet 

and is comprised of, from base to top, the Salt Wash, 

Recapture, Westwater Canyon, and Brushy Basin 

Members. General descriptions of each member follow; more detailed local information is given under 

description of the principal mining districts.

SALT WASH MEMBER

The Salt Wash Member is present only in northwestern San Juan County where it constitutes the southern 

part of a fanlike unit that extends from northeastern 

Arizona into Utah and Colorado (Craig and others, 

1955, p. 138, fig. 21). The Salt Wash rests on the Bluff 

Sandstone and grades into the overlying Recapture 

Member and, southward, interfingers with and pinches 

out beneath the Recapture Member along an eastwardtrending line approximately at the north end of the 

Chuska Mountains. In northwestern New Mexico the 

Salt Wash Member crops out only near the Arizona 

line where, in the Shiprock district, it has a maximum 

thickness of 220 feet. Eastward from the outcrop the 

general lithology is the same, and the configuration 

of the member is only modified somewhat from the 

interpretation shown by Craig and others (1955). 

Recent work, based largely on rather sparse subsurface 

information, indicates that the member generally thickens northward and has a maximum thickness in New 

Mexico of about 300 feet in the area northeast of Shiprock near the Colorado line (L. C. Craig, written commun., July 1961).

In New Mexico the Salt Wash is mostly a reddish-brown to light-brown or gray medium-grained 

sandstone which is interbedded with some mudstone. 

The sandstone units generally range in thickness 

from a few feet to several tens of feet and are characteristically crossbedded. Studies of the dip directions 

of the cross laminae in the sandstone of the Shiprock 

and Chuska districts indicate a general eastward trend 

(Craig and others, 1955, p. 145, fig. 26). Fossil plant 

material, mostly in the form of coalified fragments and 

silicified logs, occur locally in the sandstone units.

RECAPTURE MEMBER

The Recapture Member crops out along the margins 

and is recognized in the subsurface of the San Juan 

Basin, crops out locally east of the Rio Grande, and 

crops out in northeastern Arizona and in adjoining 

parts of Utah and Colorado. The Recapture is the br.sal 

unit of the Morrison Formation in most of northwiistern New Mexico, but in northwestern San Juan County 

and in adjoining parts of Arizona, Utah, and Colorado 

it is underlain by the Salt Wash Member. The Recapture generally intertongues with and grades into the 

Cow Springs Sandstone to the southwest, and is not 

recognizable south of Albuquerque and east of Santa 

Fe (L.C. Craig, written commun., July 1961). Soutl of 

Gallup its former southern extent is unknown because 

it was removed by pre-Dakota erosion. South of Grants 

it thins abruptly and apparently either wedges out 

about 3 miles south of U.S. Highway 66 or is norexistent because of removal by pre-Dakota erosion. In 

the vicinity of Laguna it is relatively thin and locally difficult to separate from the Westwater Canyon 

and Brushy Basin Members.

The Recapture is generally about 200-300 feet thick, 

but ranges in thickness from 0 to about 600 feet. In 

New Mexico it is thickest in the Chuska district in 

western San Juan County, where it is about 500 feet 

thick and consists mostly of gray and buff locally conglomeratic sandstone and some interbedded mudstone 

and siltstone. Elsewhere it is mostly maroon and gray, 

relatively thin bedded, and consists of fine-grained 

interbedded sandstone and siltstone. Fossil plant debris, which generally consists of coalified and macerated material, occurs locally in the Chuska district 

where it is principally in sandstone.

Studies of the dip directions of the cross-laminae of 

the sandstone of the Recapture in New Mexico are 

available only for a few localities along the south and 

west margins of the San Juan Basin. In these localities 

dip directions that are generally northeastward indicate a southwestern source for the Recapture sediments 

(L.C. Craig, written commun., July 1961). Locally, 

however, the dip directions may differ, as in the Chuska 

district where the direction of streamflow in the upper 

ore-bearing part of the Recapture is about N. 30° W. 

(J. W. Blagbrough, written commun., 1959).

WESTWATER CANYON MEMBER

The Westwater Canyon Member, which overlies the 

Recapture, crops out in the same general areas and has 

about the same distribution pattern as the Recapture 

Member. In New Mexico, in the vicinity of the Arize naNew Mexico border, the Westwater Canyon is alout 

300 feet thick, from where it grades and intertong-ues
20 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

northward into the Brushy Basin Member in southwestern Colorado. Eastward it thins and is about 100- 

250 feet thick on the east side of the San Juan Basin 

and north of Albuquerque; it is not recognizable south 

of Albuquerque and east of Santa Pe (L. C. Craig, 

written commun., July 1961). Along its south margin 

the Westwater Canyon thins to extinction mostly as 

a result of depositional thinning and partly from removal by pre-Dakota erosion. Its former southern 

extent is unknown but likely was near the southernmost 

exposures. East of Mount Taylor, in the Laguna district, it is thin, locally absent, or inseparable from the 

Brushy Basin and Recapture Members (Freeman and 

Hilpert, 1956, p. 316; Hilpert and Moench, 1960, p. 435, 

fig. 3; Hilpert, 1963, p. 16, fig. 2).

The Westwater Canyon Member is mostly a reddishbrown or gray medium- to coarse-grained arkosic 

sandstone that includes subordinate interbeds of claystone. It is conglomeratic in southwestern San Juan 

and western McKinley Counties, and locally conglomeratic in eastern McKinley County. It generally becomes finer northeastward. In the southern part of 

the Chama Basin, Rio Arriba County, it is generally 

fine to medium grained. The sandstone strata are composed of many lensing, cross-laminated beds having 

channeled scour surfaces at their bases. Dip directions 

of the cross-laminae have been studied in the same 

general localities as the Recapture Member and show a 

similar northeastward trend and southeastward source 

of the sediments, except in the Cuchillo Arroyo area 

north of Albuquerque where they indicate a northwestward-dipping component (L. C. Craig, written commun., July 1961). Locally, however, the trends vary 

somewhat from the regional pattern and this could be a 

local variant.

Plant material in the Westwater Canyon consists of 

scattered fragments of small logs or limbs, most of 

which are silicified, and local concentrations of coalified fragments of plants. These fragments are rather 

sparse in sandstone and locally are concentrated as relatively fine debris or "trash" near the base of mudstone 

units. Another probable plant derivative is a finegrained black or brownish-gray material that coats the 

sand grains and fills the space between the grains. 

This material is coextensive with the uranium deposits in the Ambrosia Lake, Laguna, and Gallup districts. It is mostly a carbon compound and is almost 

totally insoluble in acids, alkalies, and organic solvents ; its carbon, hydrogen, nitrogen, and oxygen contents are more nearly similar to those of low-rank 

coals than to those of petroliferous substances, in addition, infrared absorption spectrographs of this substance are more nearly like the spectrographs of lowrank coals than to those of asphaltic materials (Granger 

and others, 1961, p. 1196). Moreover, the presence of 

this material in fluvial sandstone units is irore readily 

explained as a derivative from nearby plart materials 

than as an asphaltic or petroleum residue, which would 

have to be brought in from an external source bed, as 

assumed by Zitting, Masters, Groth, and Y^ebb (1957, 

p. 55-56).

BRUSHY BASIN MEMBER

The Brushy Basin Member is the uppermost member 

of the Morrison Formation and in Arizona, Utah, and 

Colorado has the same general regional distribution as 

the Salt Wash Member (Craig and others, 1955, p. 155, 

fig. 29). In New Mexico, however, the Brushy Basin 

extends farther south and crops out in the same general areas and has about the same distribution pattern 

as the Recapture and Westwater Canyon Members. It 

generally thickens northeastward and ranges in thickness from about 100 to 300 feet, but locally is more than 

500 feet. It grades at the base into, and interfingers 

locally with, the Westwater Canyon Member. Because 

the Brushy Basin and Westwater Canyon Members 

interfinger, the contact between them locally is determined arbitrarily. The Brushy Basin is c^erlain unconformably by the Dakota Sandstone of Cretaceous 

age which along the south margin of the San Juan 

Basin rests on and southward overlaps the beveled edge 

of the Brushy Basin.

The Brushy Basin in New Mexico consists mostly of 

light-greenish-gray and some varicolored claystone. 

The claystone is interbedded with sandftone lenses 

which are lithologically similar to the sandstone lenses 

of the Westwater Canyon.

Along the south margin of the San Juan Basin, these 

sandstone lenses are described later under the principal mining districts.

Another sandstone unit, which occurs at the top of 

the Brushy Basin in Rio Arriba County, is described 

because of its thickness, probable broad extent, and 

similarity to the other ore-bearing units. This unit 

directly underlies the Dakota Sandstone, and where 

measured at Ghost Ranch in sec. 35, T. 25 N., R. 4 E., by 

Craig and Freeman (Craig and others, 1959) is described as about 100 feet thick and as consisting of a 

white to very pale orange fine- to coarse-grr ined quartz 

sandstone that contains lenses and stringers of chert 

granules and pebbles and is channeled and crosslaminated. A lithologically similar unit, 124 feet thick, in the 

same stratigraphic position was measured by Craig 

(Craig and others, 1959) at Cuchillo Arroyo, near 

Warm Springs, on the east side of the San Juan Basin.

From available information, determination of how 

far north in the Chama Basin this unit Bright extend
STRATIGRAPHY 21

is somewhat speculative. Across the south margin of 

the basin it is apparently exposed through a distance 

of about 25 miles, and there is no reason to believe it extends a lesser distance to the north. Southward it could 

also extend continuously to the vicinity of Warm 

Springs and beyond, but this is only a possibility. It 

occurs at the same stratigraphic position as the Jackpile 

sandstone, an ore-bearing unit in the Laguna district, 

but does not connect with it. The Jackpile pinches and 

tongues out northward in the vicinity of Mesa Prieta, 

south of Warm Springs (Freeman and Hilpert, 1956; 

Schlee and Moench, 1961).

ROCKS OF CRETACEOUS AGE

Overlying the rocks of the Jurassic System is a 

sequence of near-shore marine and fluvial formations 

of Cretaceous 'age that were laid down during several 

southwestwarcl transgressions and northeastward regressions of a sea that covered all of northwestern New 

Mexico (Sears and others, 1941). This sequence consists of gray shale, brownish-gray sandstone, and interbedded carbonaceous shale and coal and has a thickness that ranges from about 3,000 feet in Socorro and 

Catron Counties (Dane and others, 1957, p. 191-192) to 

about 7,000 feet in northern San Juan County (Eeeside, 

1924, p. 4-5). The complete sequence is present only in 

the northern part of the San Juan Basin; southward 

the upper formations have been removed by erosion, 

and east of the Rio Grande only isolated remnants 

crop out in the ranges and basins in Santa Fe, Sandoval, Bernalillo, and Socorro Counties.

From base to top, the formations of Cretaceous age 

are the Dakota Sandstone and Mancos Shale; the 

Gallup Sandstone, Crevasse Canyon Formation, Point 

Lookout Sandstone, Menefee Formation, and Cliff 

House Sandstone, which constitute the Mesaverde 

Group; and the Lewis Shale, Pictured Cliffs Sandstone, 

Fruitland Formation, Kirtland Shale, and Ojo Alamo 

Sandstone. (See p. 6, this report.) The Animas Formation is described with Cretaceous formations, although 

it is recognized as being Late Cretaceous and Paleocene. These formations are briefly described.

DAKOTA SANDSTONE

The basal unit of Cretaceous age in northwestern 

New Mexico is generally referred to as the Dakota 

Sandstone. It crops out around the margins of the San 

Juan Basin and in small scattered localities in other 

parts of the area (Pike, 1947, p. 6-8; Dane, 1960). In 

the northern part of the area it rests on the Morrison 

Formation of Jurassic age, but in the southern part, 

because of pre-Dakota warping and subsequent erosion, progressively overlaps southward onto older rocks

of Jurassic and Triassic ages. The Dakota consist^1 of 

gray-brown quartz sandstone, some gray interbedded 

shale, and locally, generally near the base, conglomerate 

lenses and carbonaceous shale or coal. The sandstone 

units are crossbedded and contain numerous mold^ of 

coalified plant debris. Local scours at the base, Which 

contain sandstone lenses that range in thickness fror^ 20 

to 50 feet and in width from 300 to 800 feet, are clustered 

along the outcrop in McKinley County (Mirsky, 19^3). 

The Dakota ranges in thickness from 0 to 200 feet and 

averages about 100 feet. In northwestern New Mexico it 

was assigned a Late Cretaceous age by Oobban and Preside (1952, chart lOb), and fossil data from the b""5al 

part near Acoma confirm that it is not older than Late 

Cretaceous (Dane, 1959, p. 90). Dane and Bachman 

(1957b, p. 97-98), however, indicated that in the Gallup 

area the lower part may be Early Cretaceous in age 'and 

the upper part Late Cretaceous. They interpreted 

the Dakota in the Gallup area as a composite unit 

that is partly fluvial, partly lagoonal, and partly an offshore sandy marine unit. They interpreted the lower 

part as a partly fluvial deposit that may be equivalent 

to those deposited in marine waters that transgressed 

from the east and south; they interpreted the upper part 

as including rocks that were deposited in association 

with a marine transgression from the north and noHheast. The age relations suggest that equivalents of the 

older beds near Gallup either were not deposited in the 

southeastern part of the area or were removed in Late 

Cretaceous time by the southwestward advance of the 

sea. The channel-filled scours at the base in McKinley 

County (Mirsky, 1953) probably are equivalents of the 

fluvial beds recognized by Dane and Bachman (19£7b) 

in the earlier marine transgression. The highland area 

that contributed these sediments probably was situated 

west of central Arizona (Eeeside, 1944).

MANCOS SHALE

The Mancos Shale (Cross, 1899) overlies the Dal-ota 

Sandstone and has a similar distribution in northwestern New Mexico (Pike, 1947). The Mancos consists of 

gray marine shale and subordinate amounts of finegrained sandstone; it ranges in thickness from a few 

hundred feet in the southern part of the area (Dane 

and others, 1957, p. 186) to about 2,000 feet in the 

northern part (Hayes and Zapp, 1955; Wood and 

others, 1948).

GALLUP SANDSTONE

In the general area of the San Juan Basin and in 

parts of Catron and Socorro Counties, the Mancos 

Shale is overlain by the Mesaverde Group, which is
22 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

about 1,000 feet thick and comprises, in ascending order, the Gallup Sandstone, Crevasse Canyon Formation, Point Lookout Sandstone, Menefee Formation, 

and the Cliff House Sandstone (Holmes, 1877, p. 244; 

Collier, 1919; Beaumont and others, 1956). The Gallup Sandstone (Sears, 1925), the basal formation of 

the group, crops out around the south and west margins of the San Juan Basin and south of the Zuni 

Mountains in Valencia, Catron, and Socorro Counties. 

It is a gray-white medium- to coarse-grained crossbedded sandstone interbedded with some shale and is 

locally coal bearing, generally near the top. It is about 

250 feet thick near Gallup and south of the Zuni 

Mountains but thins northeastward and pinches out 

into the Mancos Shale under the San Juan Basin 

(Beaumont and others, 1956).

CREVASSE CANYON FORMATION

The Crevasse Canyon Formation, which overlies the 

Gallup Sandstone, crops out in the southern part of 

the San Juan Basin and in Valencia, Catron, and Socorro Counties (Alien and Balk, 1954, p. 91-92; Beaumont and others, 1956; Dane and others, 1957). It is 

a sequence of lenticular sandstone units, light-colored 

clay, and some coal beds. It has a thickness of about 

750 feet in the southern part of the area, but northeastward from Gallup it thins and tongues out under 

the San Juan Basin (Beaumont and others, 1956). 

South of the basin it is only partly exposed, and in 

Socorro and Catron Counties most of it has been removed by erosion (Dane and others, 1957).

POINT LOOKOUT SANDSTONE

The Point Lookout Sandstone (Collier, 1919) crops 

out around the San Juan Basin and probably occurs 

as an erosional remnant in the Datil Mountains in 

western Socorro and eastern Oatron Counties (Dane and 

others, 1957). The Point Lookout Sandstone is the basal 

formation of the Mesaverde Group in the northeastern part of the San Juan Basin where it rests on the 

Mancos Shale (Beaumont and others, 1956), p. 2153). 

In the southwestern part of the basin it rests on the 

Crevasse Canyon Formation which intertongues northeastward with the Mancos Shale and overlies the Gallup 

Sandstone, the basal formation of the Mesaverde Group 

in the southwestern part of the basin (Beaumont and 

others, 1956, fig. 3).

The Point Lookout is a gray-brown to white fine- to 

medium-grained thin- and parallel-bedded sandstone. 

It is 350 feet thick in the northeastern part of the 

San Juan Basin, but thins southwestward to about 100 

feet along the southwestern part of the basin.

MENEFEE FORMATION

The Menefee Formation (Collier, 1919) overlies the 

Point Lookout Sandstone and crops out around the margins of the San Juan Basin, but has been removed by 

erosion farther south. From thicknesses of about 1,500 

to 2,000 feet near the center of the basin the Menefee 

thins northward and grades into the overlying Cliff 

House Sandstone (Beaumont and others, 1956). The 

Menefee consists of gray, brown, and greenish-gray 

siltstone and shale, gray to buff lenticular c^ossbedded 

sandstone and coal.

CLIFF HOUSE SANDSTONE

The Cliff House Sandstone (Collier, 1919), the uppermost formation in the Mesaverde Group, overlies the 

Menefee Formation and crops out in western San 

Juan, northeastern McKinley, and northwestern Sandoval Counties, and possibly along the northeastern 

side of the San Juan Basin principally as the La 

Ventana Tongue (Beaumont and others, 1956). The La 

Ventana Tongue may connect westward with the Cliff 

House Sandstone under the basin.

Both the Cliff House Sandstone and the La Ventana 

Tongue are thick-bedded marine sandstone units with 

some shale. Both units thin northward by grading into 

the overlying Lewis Shale. The Cliff House- Sandstone 

diminishes in thickness northward from about 350 feet 

in northeastern McKinley County, and the La Ventana Tongue thins from about 1,000 feet in northwestern Sandoval County to about 100 feet in northern 

Kio Arriba County.

MESAVERDE GROUP UNDIVIDED

The Mesaverde Group is shown on plata 1 in several widely separated areas as undivided. One area is 

in Catron and Socorro Counties and another is in 

southeastern and western Santa Fe Counties.

LEWIS SHALE

The Lewis Shale (Cross and Spencer, ]899) overlies the Cliff House Sandstone and crops out in San 

Juan, western Rio Arriba, northeastern McFinley, and 

northwestern Sandoval Counties. It is a g~ay marine 

shale and has a maximum thickness of f.bout 1,500 

feet in Rio Arriba County. Southwestward it grades 

into the Cliff House Sandstone and overlyir* Pictured 

Cliffs Sandstone (Beaumont and others, 1956; Hayes 

and Zapp, 1955).

PICTURED CLIFFS SANDSTONE

The Pictured Cliffs Sandstone (Holmes, 1877, p. 248; 

Reeside, 1924, p. 18-19) generally overlies and locally 

grades into the upper part of the Lewis Shale and
STRATIGRAPHY 23

crops out in San Juan, northern Rio Arriba, northeastern McKinley, and northwestern Sandoval Counties (Beaumont and others, 1956). It is a white to 

brown marine cliff-forming sandstone interbedded with 

some gray shale and ranges in thickness from 70 to 

about 400 feet (Reeside, 1924; Hayes and Zapp, 1955).

FRUITLAND FORMATION AND KIRTLAND SHALE

The Fruitland Formation, winch is the lowermost, 

Shale crop out in San Juan, northeastern McKinley, 

northwestern Sandoval, and northwestern Rio Arriba 

Counties and overlie the Pictured Cliffs Sandstone and 

locally overlie the Lewis Shale (Bauer, 1916, p. 274; 

Reeside, 1924). Both formations are mostly fresh-water 

deposits and are partly fluvial.

The Fruitland Formation, which is the lowermost, 

ranges in thickness from 0 to about 500 feet in New 

Mexico and generally thins from San Juan and McKinley Counties eastward and grades out or is cut out 

under younger beds in Rio Arriba County (Reeside, 

1924, p. 20). The Fruitland consists of gray and brown 

sandstone, olive-gray shale, and some coal. The sandstone units are highly lenticular, indurated, and irregularly bedded and range in thickness from a few feet 

to as much as 100 feet.

The Kirtland Shale ranges in thickness from 0 to 

about 1,200 feet in New Mexico and, like the Fruitland, thins eastward and grades out or is cut out under 

younger beds in Rio Arriba County (Reeside, 1924, p. 

22; Dane, 1946). The Kirtland Shale overlies the 

Fruitland Formation in the western and southern parts 

of the area, but eastward and northward the two formations intergrade and are difficult to differentiate 

(Dane, 1946). The Kirtland is dominantly gray shale 

interbedded with sandstone, but contains some black 

carbonaceous layers. The sandstone beds are fine 

grained and irregularly bedded and are generally less 

than 20 feet thick.

OJO ALAMO SANDSTONE

The Ojo Alamo Sandstone (Brown, 1910) crops out 

in San Juan, northeastern McKinley, and northwestern 

Sandoval Counties and overlies the Kirtland Shale. 

The Ojo Alamo ranges in thickness from 0 to 400 feet 

and, from north-central San Juan County, generally 

thins eastward and northward and grades at the base 

into the underlying Kirtland Shale and into the McDermott Formation (Dane, 1936, p. 121; Hayes and 

Zapp, 1955). The Ojo Alamo consists of fluvial coarsegrained crossbedded buff to white arkosic sandstone 

interbedded with some gray and yellow shale. It is 

locally conglomeratic; the pebbles are well rounded and 

are composed of jaspery quartz, chert, vein quartz,

quartzite, rhyolite, andesite, porphyry, granite, gneiss, 

and schist; the sandstone contains much silicified wood, 

largely 'as logs (Reeside, 1924, p. 28-30).

ANIMAS FORMATION (UPPER CRETACEOUS 

AND FALEOCENE)

The Animas Formation (Reeside, 1924, p. 32) c~ops 

out in western Rio Arriba County where it overlies 

the Fruitland Formation and overlies the Lewis Shale 

where the Fruitland Formation and Pictured Oiffs 

Sandstone are absent (Dane, 1946). In north-certral 

San Juan County and the adjoining part of Colorado, the lower few hundred feet of the Animas, 

referred to by Reeside (1924, p. 24-26) -as the McDermott Formation, is included in the Animas Formation as the McDermott Member (Barnes and others, 

1954). On the map (pi. 1) the Animas is mapped 

with the Nacimiento Formation in parts of San Juan 

County.

In New Mexico the Animas has a maximum thickness of about 3,000 feet in Rio Arriba County near 

the Colorado border, from where it thins and grades 

southward into the Nacimiento Formation (I>-ne, 

1946) and thins and probably grades southwest^ard 

into the Ojo Alamo Sandstone and upper part of the 

Kirtland Shale (Barnes and others, 1954; Hayes and 

Zapp, 1955). The Animas is a sequence of congkmeratic, greenish-gray, and tan sandstone, siltstone, and 

shale that contains considerable amounts of andesitic 

debris. The sandstone units, which are as much as 

100 feet thick, are very lenticular, massive, coar.^ to 

fine grained, and locally contain silicified wood. The 

shale and siltstone contain some carbonaceous material and locally contain thin coal seams. The beds in 

the McDermott are generally purple, contain some 

well-rounded pebbles of quartz, quartzite, and chert, 

and are coarser grained than are other parts of the

Animas.

ROCKS OP TERTIARY AGE

Rocks of Tertiary age in northwestern New Mexico 

are widely distributed and consist of continental sediments and igneous intrusive and extrusive rocks, legally 

at least several thousand feet thick. For convenier'ie of 

description, the rocks are described separately for the 

following areas: (1) the San Juan Basin, (2) the Datil 

section, and (3) the Rio Grande trough and vicinity.

SAN JUAN BASIN

In the San Juan Basin the rocks of Tertiary ag*^ are 

all fluvial sediments and consist of the upper part 

of the Animas Formation (described under Creta^ous 

rocks), the Nacimiento Formation, and the San Jose 

Formation in the northeastern part of the basin
24 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

and the Chuska Sandstone on the west flank of the 

basin.

NACIMIENTO FORMATION

The Nacimiento Formation, which includes beds 

equivalent to the Puerco and Torrejon Formations 

in the southern part of the San Juan Basin (Dane, 

1936, p. 122-124; 1946), crops out in San Juan and 

northwestern Sandoval Counties and overlies the Ojo 

Alamo Sandstone. The Nacimiento is about 600 feet 

thick in the southern part of the area, from where it 

coarsens and thickens northward to about 1,000 feet 

and grades into the Animas Formation in Rio Arriba 

County (Dane, 1946). The Nacimiento Formation is a 

sequence of banded light- and dark-gray clay and 

subordinate lenses of fine- to medium-grained buff 

quartz sandstone. The clay is darker and somewhat 

carbonaceous near the base, and the sandstone is clayey, 

crossbedded, very lenticular, and most abundant in the 

upper part.

SAN JOSE FORMATION

The San Jose Formation crops out in northeastern 

San Juan, northwestern Sandoval, and western Rio 

Arriba Counties; it unconformably overlies the Nacimiento and Animas Formations and is the uppermost 

unit of Tertiary age in the northeastern part of 

the San Juan Basin. The San Jose principally is interbedded gray, purple, and varicolored shale or clay, 

and interbedded copper-red, gray, and white, conglomeratic sandstone units, and has a total thickness of 

about 3,000 feet (Dane, 1046; Simpson, 1948). The 

sandstone units generally are arkosic, contain some 

thin interbedded clays, locally contain coalified wood 

or plant fragments, and are massive, crossbedded, lenticular, and as much as 100 feet thick.

CHUSKA SANDSTONE

The Chusba Sandstone (Gregory, 1917, p. 80), of Pliocene (?) age, crops out near the Arizona line in the 

Chuska Mountains in San Juan and McKinley Counties, where it rests on the beveled edge of Cretaceous rocks. It is a light-gray to light-brown thin- to 

thick-bedded sandstone and contains some interbedded 

siltstone and shale. It ranges in thickness from about 

700 to 900 feet and is fluvial and perhaps partly eolian 

in origin (Alien and Balk, 1954, p. 99). Carbonaceous 

material has not been noted in the Chuska.

DATIL SECTION*

Rocks of Tertiary age in the Datil section consist 

mostly of the fluvial Baca Formation of Eocene(?) 

age and the overlying volcanic rocks of the Datil 

Formation of late Tertiary age and total about 3,000 

feet in thickness.

BACA FORMATION

The Baca Formation crops out in northern Catron 

and west-central Socorro Counties as a discontinuous 

westward-trending 'belt, where it overlies beveled 

Cretaceous rocks. It crops out locally east of the Rio 

Grande, where it overlies beveled Mesozoic and Paleozoic rocks. The description of the Baca at the type 

section, in the north Bear Mountains, and east of the 

Rio Grande is taken from Wilpolt, MacAlpin, Bates, 

and Vorbe (1946) and Wilpolt and Wan-,k (1951). 

West of the Rio Grande, except at the type section, the 

description is from G. O. Bachman, E. H. Baltz, and 

R. L. Griggs (written commun., 1957).

At the type section and in the area east of the Rio 

Grande the Baca consists of coarse conglomerate, red 

and white sandstone, and red clay. The conglomerate 

contains abundant pebbles, cobbles, and boulders, 

which were derived from Precambrian quartzite and 

granite, Pennsylvanian limestone, and detritus from the 

Permian Abo Formation. West of the Bear Mountains 

the Baca consists of salmon-pink medium- to coarsegrained cross-laminated sandstone, salmon-pink to 

distinctive dark-red interbeds of shale and siltstone, 

and a few interbeds of gray shale. Pebble conglomerate, chiefly composed of quartzite, occurs n^r the top 

of the formation locally. In places, carbonaceous material is abundant in association with gray shale and 

as detritus in sandstone.

East of the Rio Grande the Baca Formation ranges 

in thickness from 80 to 140 feet, and south, of the map 

area near Carthage, N. Mex., it is about 1,000 feet thick 

(Gardner, 1910, p. 454). West of the Rio Grande the 

Baca is about 700 feet thick at the type section and is 

estimated to be about 1,500 feet in the northern part 

of the Datil Mountains. In the vicinit;r of Carthage the Baca is late Eocene in age and may be the 

same age in other parts of Socorro County and in 

Catron County.

DATIL FORMATION

The Datil Formation crops out extensively in Socorro 

and in Catron counties; locally it is conformable 

on the Baca Formation in the Datil Mountains, but 

elsewhere overlaps the Baca and is imconformable on 

the beveled edges of Mesozoic and Paleozoic rocks 

(Winchester, 1920; Wilpolt and others, 19*6; Wilpolt 

and Wanek, 1951; G. O. Bachman, E. H. Baltz, and 

R. L. Griggs, written commun., 1957).

The Datil Formation consists of purple, and lesser 

amounts of red and gray, volcanic flows, agglomerates, welded tuffs, and tuffs of felsic and m^fic composition and some conglomerate and sandstone. It ranges 

in thickness from 0 to about 2,000 feet.
STRUCTURE 25

BIO GRANDE TBOUGH AND VICINITY

Rocks of Tertiary age in the Rio Grande trough and 

vicinity are a heterogeneous assortment of fluvial sediments, water-laid volcanic debris, and locally, volcanic flows and breccias that are at least several thousand 

feet thick. These rocks are described below under "Older Volcanic Rocks of Jemez Mountains," "Galisteo Formation," "Espinaso Volcanics of Stearns (1943)," "Popotosa Formation," and "Santa Fe Group." Intrusive 

rocks of varied composition and form occur locally, 

but are described in the section that follows.

OLDER VOLCANIC ROCKS OF JEMEZ MOUNTAINS

The rocks that crop out in the Jemez Mountains 

area, northeastern Sandoval and southeastern Rio Arriba Counties, consist mostly of a sequence of rhyolitic to basaltic flows, pyroclastics, and intrusives, .of 

Tertiary and Quaternary ages, and some prevolcanic 

sedimentary rocks. The oldest of these igneous rocks 

and the prevolcanic sedimentary rocks are included on 

plate 1 as "Older Volcanic Rocks of the Jemez 

Mountains."

GALISTEO FORMATION

The Galisteo Formation crops out along the east 

side of the Rio Grande northeast of the Sandia Mountains in southeastern Sandoval and western Santa Fe 

Counties, where it rests unconformably on the Mancos 

Shale and Mesaverde Group (Stearns, 1943). The Galisteo ranges in thickness from 900 feet along its 

northwest margin in Sandoval County to more than 

4,000 feet along its southeast margin in Santa Fe 

County (Stearns, 1943, p. 309). It consists of fluvial 

sandstone and conglomerate, clay, and some limestone and water-laid tuff. The sandstone is gray to 

buff, locally pink, and is quartzose and locally arkosic. Silicified wood is abundant in many sandstone 

beds, and coalified plant debris occurs locally. The 

conglomerate pebbles consist chiefly of chert and 

quartzite, but locally also consist of granite, porphyry, 

metamorphic rocks, and some limestone (Stearns, 1943).

The Galisteo is late Eocene in age according to 

Stearns (1953, p. 467) and possibly correlative in 

age with the Baca Formation (Wilpolt and others, 

1946) and may be as young as Oligocene.

ESFINASO VOLCANICS OF STEARNS (1943)

The Espinaso Volcanics of Stearns (1943), which 

are 400 to about 1,500 feet thick, crop out locally 

north and west of the Ortiz Mountains, Sandoval and 

Santa Fe Counties, and overlie the Galisteo Formation (Stearns, 1953, p. 467; Disbrow and Stoll, 1957, 

p. 11-12). The Espinaso Volcanics are latitic and consist of water-laid volcanic breccia, conglomerate, tuff, 

and some flows (Stearns, 1953). The Espinaso are

mapped on plate 1 with the Santa Fe Group undivided. 

Age of the Espinaso Volcanics is uncertain. The formation is assigned to late Eocene by Stearns (1953, 

p. 467-468), and to Oligocene (?) by Disbrow and 

Stoll (1957). From indirect evidence (Sun and Baldwin, 1958, p. 7-23; Spiegel and Baldwin, 1963, p. 37), 

it could range from Oligocene to late Miocene.

POPOTOSA FORMATION

The Popotosa Formation, of late Miocene age, crops 

out along the west side of the Rio Grande trough in 

Socorro County, rests unconfonnably on volcanic breccia and consists of water-laid volcanic debris and gray 

and buff tuffaceous sandstone, siltstone, and conglomerate. It has a total thickness of 3,000-5,000 feet (Denny, 1940). The sandstone lenses in the Popotosa are 

generally crossbedded, very lenticular, and contain 

scattered plant remains.

SANTA FE GROUP (MIOCENE TO PLEISTOCENE!)

The Santa Fe Group (Baldwin, 1956) crops out in 

the Rio Grande trough and vicinity from Rio Arrib<\ to 

Socorro Counties, unconformably overlies the C: °>neguilla Limburgite of Stearns (1953), the Espiraso 

Volcanics of Stearns (1943, p. 316), and the Popotosa Formation, and has a total thickness of at l<*ast 

several thousand feet. The Santa Fe Group consists of 

fluvial, reddish-brown, buff, and gray unconsolidrted 

sandstone, siltstone, claystone, conglomerate, and locally tuff, andesite, and other volcanic rocks. In age the 

group varies from place to place but probably ranges 

from late Miocene to late Pliocene and possibly extends locally into middle (?) Miocene and Pleistocene 

(?) (Spiegel and Baldwin, 1963, p. 62-63). For a more 

detailed description of the Santa Fe Group and ite relations to the Espinaso Volcanics and Cieneguilla Limburgite, see Spiegel and Baldwin (1963, p. 21-78), 

Sun and Baldwin (1958, p. 7-18), and Disbrow and 

Stoll (1957).

INTRUSIVE BOCKS OF VABIED COMPOSITION 

AND FORM

Most of the larger outcrops of intrusive igneous 

rocks of Tertiary age in northwestern New Meyico 

are shown in red on plate 1. These rocks are widely 

distributed and are of felsic, mafic, and intermediate 

composition. They range from dikes and sills to irregular necklike, domelike, or laccolithic bodies and 

stocks; they intrude rocks that range in age f~om 

Paleozoic to Tertiary.

STRUCTURE

The principal structural features of northwestern 

New Mexico are roughly outlined by the boundaries 

of the physiographic provinces (fig. 1). These fea-
26 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

tures are: (1) The San Juan basin and adjoining uplifts and the Datil-Mount Taylor volcanic field, in the 

Colorado Plateaus province; (2) the fault-block mountains and intervening depressions of the Basin and 

Range province; and (3) the domal ranges and intervening basins of the Southern Rocky Mountains 

province.

The San Juan basin is a broad saucer-shaped structural feature that constitutes about one-third of the 

mapped area and that extends northward into southern Colorado. It is characterized by Paleozoic, Mesozoic, and Tertiary sedimentary beds which are several 

thousand feet thick and which dip gently from the 

basin margins toward the center, and by relatively 

small elongate domes or uplifts and synclinal depressions around the margins of the basin. These uplifts 

and depressions have areal dimensions that are generally tens of miles across (fig. 3).

The principal uplifts are the Zuni, Defiance, Lucero, Nacimiento, and San Juan. The Nacimiento and 

San Juan uplifts are in the Southern Rocky Mountains province, but are included here for descriptive 

purposes. The Zuni uplift is on the southwestern side 

of the San Juan basin and is elongate northwestward; 

the Defiance, Nacimiento, and Lucero uplifts are on the 

west, east, and southeast sides of the basin, respectively, and are elongate northward; the San Juan 

uplift is on the northeast side of the basin, trends 

northwestward, and is mostly in Colorado.

The principal structural depressions around the 

San Juan basin are the Chama basin, the Gallup 

and Acoma sags, and the McCartys syncline. 

The Chama basin is a synclinal structure on the 

northeast side of the San Juan basin; it is cradled 

between the north end of the Nacimiento uplift and 

the west flank of the San Juan uplift, and trends 

northward. The McCartys syncline, which is on the 

southeast side of the San Juan basin, lies between the 

Zuni and Lucero uplifts in the west side of the Acoma 

sag, and plunges northward. The Gallup sag is a synclinal depression that lies between the Zuni and 

Defiance uplifts.

Other structural features that are marginal to the 

San Juan basin and adjoining uplifts are monoclinal 

folds, which are comparable in length to the uplifts and 

generally dip basinward from the flanks of the uplifts. 

Most prominent of these is the Hogback monocline 

which strikes northeastward along the northwest margin of the basin, the Defiance monocline which generally 

strikes northward along the east flank of the Defiance 

uplift, the Nacimiento monocline which strikes northward along the west flank of the Nacimiento uplift, and 

the Nutria monocline which strikes northwestward and

dips westward along the west end of the Zuni uplift. 

These monoclines generally dip steeply, are overturned 

and faulted locally, and are crenulated by numerous 

cross folds.

Also marginal to the San Juan Basin are several 

relatively small domal or anticlinal structures which 

are generally a few square miles in area! dimension. 

Of these structures, the Ambrosia dome is of particular interest because of the uranium deposits that occur 

on its flanks and in its general vicinity. Numerous volcanic structures are also marginal to the basin and the 

adjoining domal and synclinal structures and consist 

of the dioritic and partly laccolithic intrusives of the 

Carrizo Mountains and widely distributed mafic 

necks, dikes, and sills.

The Datil-Mount Taylor volcanic field generally 

lies in the Datil volcanic section of the Colorado Plateaus province and is marked by a sequence of flatlying lavas and some continental sediments of Tertiary and Quaternary ages. These beds total several 

thousand feet in thickness and generally cover flatlying marine and continental rocks of late Paleozoic, Mesozoic, and early Tertiary ages.

The structure of the Basin and Range province is 

marked by northward-trending fault-block mountains 

and intervening depressions. The Sandir., Manzano, 

and Los Pinos Mountains are the principal mountain 

blocks. They have Precambrian cores, which are 

capped by marine and continental beds that are several thousand feet thick, generally dip eastward, and 

are mostly late Paleozoic and Mesozoic in age. The 

structures of the depressions are grabens, tilted fault 

blocks, and faulted synclinal folds. Only the upper 

parts of these structures, which consist of continental 

sedimentary and some volcanic rocks of Tertiary and 

Quaternary ages, are exposed. The largest of these 

structures is the graben of the Rio Grande trough 

which, in the mapped area, extends along the west 

side of the province northward into tl <*. Southern 

Rocky Mountains province and is composed of a 

fill that totals several thousand feet in thickness. Marginal to the Rio Grande trough and the Datil section 

are several monzonitic stocks and associated igneous 

intrusives, and also marginal to it are the monozonitic laccoliths and associated intrusives of the Ortiz 

Mountains and Cerrillos Hills in Santa Fe County and 

the Valles caldera in northeastern Sandcval County.

The principal structures in the Southern Rocky 

Mountains province are the archlike Sierra Nacimiento, the San Pedro and the south end of the San 

Juan Mountains, and the structural depression of the 

north end of the Rio Grande trough. Tin mountains 

in this province have Precambrian cores that are
\<
28 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

draped on their flanks with marine and continental 

beds of late Paleozoic and Mesozoic ages and some volcanic rocks of Tertiary and Quaternary ages. The 

rocks of the Eio Grande trough, as farther south, are 

composed of continental sediments and volcanic 

debris. The west part of the trough and the east flank 

of the Sierra Nacimiento are covered by the volcanic 

pile of the Jemez Mountains which are associated 

genetically with the Valles caldera.

The principal faults in northwestern New Mexico 

are concentrated mostly along the periphery of the 

Eio Grande trough, along the flanks of the ranges of 

the Southern Eocky Mountains province, and to a 

lesser extent in the east and northeast flanks of the 

Zuni uplift and south margin of the San Juan Basin. 

Most of the faults are normal and high angle and can 

be traced along the strike for distances of as much as 

several tens of miles. In the Colorado Plateaus province 

the faults rarely have a stratigraphic throw of more 

than a few hundred feet, but in the other provinces the 

throw on some faults is as much as several thousand 

feet.

Thrust faults are less common, but one occurs along 

the west margin of the Southern Eocky Mountains 

province, and several occur in the Basin and Eange 

province. The most conspicuous thrust fault strikes 

northward for more than 50 miles along the west flank 

of the Sierra Nacimiento and the San Pedro Mountains. It dips steeply eastward and generally separates 

Precambrian crystalline rocks and pre-Triassic sedimentary rocks on the east from Permian and younger 

rocks on the west (Northrop and other, 1946). Other 

conspicuous thrusts occur on opposite sides of the Rio 

Grande trough. One skirts the east flank of Lucero 

Mesa for a distance of about 20 miles and, at different 

places along the strike, dips westward from low to 

high angle, and separates Precambrian and younger 

rocks on the west from Triassic and younger rocks on 

the east (Kelley and Wood, 1946). Other thrusts skirt 

the east flank of the Los Pinos and Manzano Mountains, generally extend along the strike for 10-15 

miles, and dip steeply westward. They generally separate Precambrian rocks on the west from Paleozoic 

rocks on the east (Eead and others, 1944; Wilpolt and 

others, 1946; Wilpolt and Wanek, 1951). The age relations and dating of the various structural features are 

discussed in the geologic history which follows.

GEOLOGIC HISTORY

The following resume of the geologic history of 

northwestern New Mexico is intended to provide a 

background for understanding the relations of the

uranium deposits to the host rocks and to the sedimentary, tectonic, and igneous structural features. 

Where pertinent, more detail is given under the 

descriptions of the mining districts anc1 the areas 

containing the deposits.

The record of the Precambrian Era is obscure, but it 

has been long and complex and has been marked by 

deformation, metamorphism, and intrusion by granite 

and associated rocks. Associated with some of the 

granite in the eastern part of Eio Arriba County 

were injections of uraniferous pegmatite and uraniferous fluorite and quartz veins.

The Precambrian rocks subsequently were eroded to 

a peneplain; after this erosion period, tH area was 

probably a stable shelf for most of the Paleozoic Era, 

(Kelley, 1955, p. 75). Some marine waters encroached 

on the northern part of the area at various times, probably during the Cambrian and again during the 

Devonian and Mississippian (Bass, 1944; Strobell, 

1958; Baltz and Eead, 1960), but the rocl-s that were 

deposited are not exposed at the surface and the record 

for northwestern New Mexico has been determined 

only from minimal well data and by projection from 

adjacent areas. The rocks that were deposited during 

this time interval comprise unnamed CVimbrian(?) 

elastics, the Elbert Formation, the Ouray Limestone, 

and the Leadville Limestone.

During Mississippian time, marine waters also 

encroached on the eastern part of the area and the 

limestone and associated elastics of the Caloso Formation of Kelley and Silver (1952), Kelly Limestone, 

and Arroyo Penasco Formation were deposited.

During late Paleozoic time, two positive structural 

features began to form; these have persisted intermittently, with modifications, to the presert and have 

had considerable influence on subsequent geologic 

events. One of the features, the antecedent of the San 

Juan uplift and generally known as tin San LuisUncompahgre uplift, was an elongate arch which 

began to form in Early Pennsylvanian time (W. WMallory, oral commun., 1963) and which extended 

from the northeastern part of the area northwestward 

into Colorado. The other feature, the antecedent of 

the Zuni and Defiance uplifts, emerged as a broad 

upwarp about the same time and extended from about 

the present position of the Zuni Mountains northwestward into Arizona. Between these t^o uplifts a 

trough formed in Early Pennsylvanian time that extended northward through the central part of the 

area and received marine and continental sediments of 

Pennsylvanian and Permian ages. These sedimentary
GEOLOGIC HISTORY 29

deposits include, in the southern part of the area, the 

Sandia Formation, Madera Limestone, Abo and Yeso 

Formations, Glorieta Sandstone, and San Andres Limestone, and in the northern part of the area, the Molas, 

Hermosa, Rico, and Cutler Formations. Locally the 

sedimentation of the upper part of the Madera Limestone and the overlying Abo and Yeso Formations was 

affected by a positive structural feature that formed in 

the vicinity of the Joyita Hills (Wilpolt and others, 

1946).

Another positive structural feature also was elevated 

in Pennsylvanian time near the center of the trough and 

extended northward through the approximate position 

of the present Nacimiento and San Pedro Mountains 

area. This structure was antecedent to the Nacimiento 

uplift, and its position is marked by nondeposition of 

the upper part of the Madera Limestone and the interbedding of clastic materials with the limestone in the 

periphery of the uplift (Wood and others, 1946).

The antecedent Zuni and Nacimiento uplifts became 

buried by Early Permian time and, during the latter 

part, of the Permian and Early Triassic, the Early 

Permian and older rocks were deformed and beveled. 

About Middle Triassic time, after the Moenkopi Formation was deposited, the San Juan highlands and 

other highlands to the southeast of the area were 

upwarped. Upwarping was accompanied by some volcanic activity elsewhere to the south and southeast of 

the mapped area (Alien, 1930; Stewart and others, 

1959, p. 566).

Northwestern New Mexico at this time was part of a 

broad plain that sloped westward into Arizona and 

northwestward into Utah and Colorado. This plain 

received clastic debris from, the highlands to the southeast and northeast and received volcanic debris from 

the south and southeast; the clastic and volcanic 

debris formed deposits that now constitute the Chinle 

Formation and part of the Dockum Formation. The 

Shinarump Member and Poleo Sandstone Lentil of 

the Chinle probably had a source in highlands to the 

south (McKee and others, 1959, p. 22). The northern 

part of the Agua Zarca Sandstone Member, as recognized by Wood, Northrop, and Cowan (1946), was 

derived from highlands to the north, and the southern part of the member from highlands to the south 

(F. G. Poole, written commun., 1957).

Relatively stable conditions existed during Late 

Triassic and Early Jurassic time and the highland 

areas were reduced to low relief. On the old flood 

plain the Wingate and Entrada Sandstones accumulated principally from wind action.

In Late Jurassic time the Zuni uplift was rejuvenated and a broad shallow basin and flood plain was 

formed to the north. This plain extended into northeastern Arizona, southeastern Utah, and southwestern 

Colorado. In the basin the Entrada Sandstone, Todilto 

Limestone, Summerville Formation, Bluff Sandstone 

(mapped with the Zuni Sandstone on pi. 1), and the 

Morrison Formation were deposited. The basin ^as 

above sea level, except for a time that a shallow emb^.yment opened to the west and permitted entrance of 

marine waters in which the Summerville Formation 

and possibly the Todilto Limestone were deposited 

(Harshbarger and others, 1957; Anderson and Kirkland, 1960). Some volcanic activity, possibly to the 

southwest of the basin of deposition, accompanied the 

Morrison deposition.

At the time of deposition of the Jurassic rocks the 

junction of the uplift, or highland, and the basin ar^as 

was within a general zone now marked approximately 

by the southern outcrop of the Jurassic rocks. This 

junction is indicated by the depositional margin of the 

Todilto Limestone (Rapaport and others, 1952), local 

conglomerate facies of the Summerville on its sonth 

margin, general coarsening of the Morrison southward 

(Craig and others, 1955), and local pinching of the 

Morrison southward against the Bluff Sandstone 

(Thaden and Santos, 1957).

While the Jurassic sediments were being deposited, 

the basin receiving them slowly and differentially subsided as the highland area was rising. These movements caused flexing or broad folding. The flexures 

occur along the south margin of the San Juan Bf sin 

near the probable margin of the old Jurassic br-sin 

(Hilpert and Moench, 1960). They probably were concentrated along the marginal zone of the old brsin 

because this would be the zone of maximum differential movement between the basin and the highland 

area. As the flexures formed, they probably partly controlled the course of the streams that deposited the 

Morrison sands and influenced the accumulation of 

the sand units because the foreset beds in the sandstone units show a dominant eastward dip and the 

sandstone units show an eastward elongation (RaDaport and others, 1952, p. 31-32; Mathewson, 1£53; 

Sharp, 1955, p. 8, 11; Hilpert and Moench, 1960).

The flexing may also have formed local basins in 

which units like the Jackpile sandstone, of local usrge, 

accumulated (Moench and Schlee, 1959). Such sandstone units contain the largest uranium deposits known 

in northwestern New Mexico. The flexing may also
30 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

have helped initiate the development of the Ambrosia 

dome and other similar structural features in the general vicinity. Moreover, intraformational folds in the 

Todilto Limestone and pipelike collapse features in 

sandstones of the Summerville, Bluff, and Morrison 

Formations probably were caused by or related to this 

flexing.

In Late Jurassic or Early Cretaceous time the southern highland area and basin margin were tilted upward 

and beveled, and all formations down to the Abo Formation were progressively cut out southward. Gradual 

subsidence followed the beveling, and a wide seaway 

then encroached on the entire area of northwestern 

New Mexico and adjoining regions. The sea spread 

gradually from the southeast and the northeast and 

left a sequence of near-shore continental and shallow 

marine sediments. These sediments range from the 

Dakota Sandstone at the base to the Pictured Cliffs 

Sandstone and total several thousand feet in thickness. 

Deposition occurred during several transgressions and 

regressions of the shoreline (Sears and others, 1941); 

these fluctuations were accompanied by settling of the 

basin and differential uplift of a rather extensive highland to the southwest which contributed the sediments.

In Late Cretaceous time, as the seas gradually withdrew, the continental Fruitland Formation and Kirtland Shale were deposited. Probably late in this interval, tectonic activity, accompanied by volcanism, in 

the San Juan Mountains area marked the emergence 

of the San Juan uplift (Hayes and Zapp, 1955). About 

the same time or shortly thereafter, the Defiance, Zuni, 

Lucero, and Nacimiento uplifts emerged, which caused 

the initial shaping of the San Juan basin; the filling 

of the basin then progressed by deposition of the continental beds of the Ojo Alamo Sandstone, Animas, 

Nacimiento, and San Jose Formations from debris 

shed by the uplifts. A pulselike rise of the uplifts is 

indicated by the beveling of the older formations by 

the younger around the basin margins (Hunt, 1956, 

p. 23-24).

The Late Cretaceous and early Tertiary tectonic 

events, generally referred to as the Laramide orogeny, 

are important in helping establish the ages of emplacement of many of the uranium deposits. Structural features that formed during this interval are the monoclinal folds on the basin sides of the uplifts that are 

marginal to the San Juan Basin, the depressions, or 

sags, between the adjacent uplifts, and the faults 

related to the development of these features. These 

features probably formed in accompaniment with the 

marked rise of the uplifts that flank the basin. This

interval is dated by the Nacimiento Formation of 

Paleocene age which was deposited during initial deepening of the basin. This deepening was largely concluded by the time of deposition of tl * San Jose 

Formation of early Eocene age which lies across the 

beveled beds of the Nacimiento Formation.

Structural features related to this age of tectonism 

are the Defiance, Nutria, and other similar monoclinal 

folds, the Acoma and Zuni sags, and tl ^ McCartys 

syncline and the faults, fractures, and related folds 

along the syncline's western flank.

Thrust faults probably formed during this time 

(Wood and others, 1946; Kelley and Wood, 1946; Wilpolt and Wanek, 1951). Some normal faults may also 

have formed as early as the thrusts, but the normal 

faults generally are younger because they displace the 

thrusts (Kelley and Wood, 1946; Wilpolt and Wanek, 

1951) and generally range in age from early Tertiary 

to Quaternary.

After the San Jose Formation was deposited, tilting 

of the San Juan Basin northward reversed the dip 

direction of the San Jose (Hunt, 1956, p. £5, 57). Some 

folding or faulting may have accompanied this tilting 

and perhaps the McCartys syncline an^ associated 

folds and fractures evolved at this time (Hunt, 1938, 

p. 75), and the Ambrosia dome and other similar structural features were accentuated. It seems more reasonable, however, to relate all these structural events with 

the preceding rise of the uplifts rather than tie them 

to simple tilting. The tilting and related events occurred in the post-early Eocene pre-late Niocene time 

interval because they postdate the San Jor °, Formation 

and precede the faulting of the Santa Fe Group along 

the Rio Grande trough.

In late early Tertiary time, probably during the 

Oligocene, volcanic activity began i^ the east-central 

part of the area and was followed in late Tertiary and 

Quaternary time by intermittent but wi<?"«pread volcanic activity throughout much of northwestern New 

Mexico. The early activity left the laccolithic intrusives and associated volcanic rocks of the Ortiz Mountains and Cerrillos Hills and the dioritic intrusives of 

the Carrizo Mountains.

The late Tertiary and Quaternary activity left the 

extensive Datil-Mount Taylor volcanic field, the intrusive bodies, flows, pyroclastic rocks, and outwash debris 

along the Rio Grande trough, and the dikes, sills, 

necks, and flows around the periphery of the San 

Juan Basin.

The Espinaso Volcanics probably were deposited
URANIUM DEPOSITS 31

during the Oligocene, about the same time that the 

intrusive rocks of the Ortiz Mountains and Cerrillos 

Hills were emplaced (Stearns, 1943, p. 309; Disbrow 

and Stoll, 1957, p. 10-12, 33-34). These events were 

probably closely followed by emplacement of the basemetal deposits in the Los Cerrillos district (Lindgren 

and others, 1910, p. 167; Disbrow and Stoll, 1957, p. 

46). Possibly about the same time, and somewhat later, 

the Datil Formation and related intrusive rocks were 

emplaced (Winchester, 1920, p. 9; Wilpolt and others, 

1946). Late in this episode or soon thereafter, the baseand precious-metal vein and replacement deposits of 

the several mining districts in Socorro County were 

formed (Lindgren and others, 1910, p. 255; Loughlin 

and Koschmann, 1942, p. 56).

The dioritic and partly laccolithic intrusives of the 

Carrizo Mountains intrude the Mancos Shale, so are 

certainly Late Cretaceous or younger. More specifically 

their age is based indirectly on ages determined for 

similar intrusives elsewhere in the Colorado Plateau 

and adjacent areas. The oldest age for such rocks was 

considered to be Late Cretaceous for some of the 

intrusives in the La Plata Mountains of southwestern 

Colorado. Shoemaker (1956, p. 162) based this age 

on the correlation of diorite porphyry debris in the 

McDermott Member of the Animas Formation, assumed to have been derived from the La Platas. Other 

dates are younger and firmer. On geomorphic evidence, 

Hunt, Averitt, and Miller (1953, p. 212) inferred the 

Henry Mountains intrusives of south-central Utah to 

be middle Tertiary in age. The laccoliths of the West 

Elk Mountains in west-central Colorado are Eocene in 

age or younger because they intrude the Wasatch Formation (Godwin and Gaskill, 1964). More recently, 

isotopic age dates indicate that the La Sal Mountains 

laccoliths in southeastern Utah are late Oligocene to 

Miocene in age (Stern and others, 1965). The laccolithic intrusives of the Ortiz and Cerrillos Hills, which 

lie immediately southeast of the Colorado Plateau 

(fig. 3), also fit this general age pattern. They intrude 

the Galisteo Formation of late Eocene age (Stearns, 

1943, p. 309) and are considered to be Oligocene in 

age (Disbrow and Stoll, 1957, p. 10-12, 33). It appears 

by analogy, therefore, that the dioritic, laccolithic, and 

related rocks of the Carrizo Mountains are most likely 

early to middle Tertiary in age, but could possibly be 

as old as Late Cretaceous.

In late Tertiary time, probably middle or late Miocene, widespread differential movements were initiated 

that were marked by uplift, some warping, and normal

faulting, and these continued intermittently until at 

least the end of Tertiary time. The displacements defined the structural boundaries between the Basin and 

Range, Colorado Plateaus, and Southern Rocky MOTUItains provinces. During this time volcanic activity continued, and from the adjoining uplifts and volcanic 

centers the Rio Grande trough and adjoining arcas 

received several thousand feet of alluvial and volcanic 

debris, including the materials in the Popotosa Formation and the Santa Fe Group.

URANIUM DEPOSITS

A uranium deposit as defined for this report is an 

occurrence that either has a content of 0.02 percent or 

more U3O8 by analysis or contains an identifiable uranium-bearing mineral. Such deposits occur in about 

30 formational units, in seven principal lithologic tyoes 

of host rocks, and in rocks of seven geologic periods. 

The host rocks and their ages are classified by symbols 

in plate 1 and, by number, the symbols show the 

deposits of mine rank. About 500 deposits or groups of 

deposits are represented, and the name, location, and 

a brief description of each is given in table 4. The 

information is summary and, between different deposits, is somewhat variable because of diverse source 

data and some company restrictions on publication of 

data on deposits, particularly subsurface data. Reference is made to the published literature for details on 

the more important deposits.

For descriptive purposes the uranium deposits are 

broadly classified as peneconcordant and vein typ°,s. 

By far the larger, more productive, and more abundant are the peneconcordant deposits. (Finch, 19£9) 

which occur in sedimentary rocks and are generally 

concordant with the bedding, but in detail cut across 

it. The discordance indicates that the deposits wore 

formed after the sediments accumulated. They differ 

from vein deposits in that fractures and faults hr.ve 

had only a subordinate or indirect influence in controlling them. The deposits occur mostly in sandstone 

and have been referred to as carnotite-, sandstone-, and 

plateau-type deposits; they also occur in limestone and 

in scattered localities in carbonaceous shale and ccal. 

Vein deposits consist of fracture fillings, stockworvs, 

mineralized breccia, and pegmatite occurrences. Tt«5y 

occur in sedimentary, igneous, and metamorphic rocks 

and differ from peneconcordant deposits in their terdency to be controlled principally by fractures and in 

their general discordance with the bedding of the 

sedimentary rocks.
32 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

TABLE 4. Uranium deposits, by county, in northwestern New Mexico

Deposit: Alternate names are shown in parentheses. Number in parentheses (3) is mine locality number shown on plate 1. 

Location: Asterisk (*) indicates land unit is unsurveyed and projected.

Description of deposit and sample: Formal members of the Morrison Formation are abbreviated: Jms, Salt Wash; Jmr, Recapture; Jmw, Westwater Canyon; Jmb, Brushy 

Basin. Informal units are abbreviated: Jmj, Jackpile sandstone of economic usage; Jmpc, Poison Canyon sandstone of economic usage. Size ranges of deposits are: 

Small, less than 1,000 tons; medium, 1,000 to 100,000 tons; large, more than 100,000 and less than 1 million tons; and very large, 1 million tons or more. For prospects, 

highest grade sample data available are listed: U or UjOs=chemical assay; eUaO8=radiometric assay.

Source of data: WC, written communication; OC, oral communication; FN, author's field notes; DH, drill-hole data; AEG, U.S. Atomic Energy Comm.; publication cited

refers to that listed in accompanying bibliography.

Name of deposit

Location

Sec. T.

Description of deposit and sample Source of data

Bernalillo County

Cerro ColoradoArchuleta prospect (LW 

claims).

 SWtfNWtf !_._ 9 N. 1 W.

Unnamed_.___ SE#22______ ION. 5 E.

Yellow and yellow-green uranium minerals occur in 

limonite-stained fractures and brecciated pockets 

in rhyolitic mass about 2,000 ft in diameter and 

300 ft high that intrudes the Santa Fe Group. 

Mineralized areas are small pockets in fracture 

zones that occur along or near eastern contact of 

what Wright (1943) interpreted as a central plug 

of quartz latite that intrudes older trachyte flows 

and volcanic breccia. Contact zone strikes northeastward and dips steeply northwestward. The 

radioactivity may be related to a smaller intrusive 

(about 300 ft in diameter) that occurs on the 

northeastern margin of what is interpreted as 

Wright's quartz latite. This small intrusive generally has a higher background count than other 

parts of the whole general mass and the generally 

vertical fractures in the smaller intrusive have a 

count that is tenfold those in the fractures of the 

larger intrusive body. Prospect workings consist 

of several shallow prospect pits and a 75-ft adit, 

which is immediately west of smaller intrusive. 

Grab sample, 0.28 percent U.

Radioactive jasperized fossil logs, about, 150 ft 

above base of Abo Formation in pink argillaceous 

arkosic sandstone. Malachite and azurite occur 

on surface of log. Occurrence is old copper prospect. Sample of jasperized wood, 0.06 percent U.

FN, 19T8; Wright 

(1943). Analysis 

by J. P. Schuch 

and J. S. Wahlberg.

E. H. Paltz, Jr., 

and H. D. Zeller 

(WC, 1953).

Catron County

Drag A Ranch.___ 31_---_---_-___ 2 N. 9 W.

Unnamed______

Red Basin 1 (S).

Unnamed. 

Do2 N.

Unnamed.

Do..

31________ W.

SEJ_NEJi 19 . 2 N. 10W.

2 N. 10 W.

2 N. 10 W.

Red Basin 2____ CWJ.WJ. 20__ 2 N. 10 W.

)___. 2 N. 10 W.

Radioactive zone in sandstone in Mesaverde Group. 

Grab sample of lower 3 in. of bed, 0.026 percent U.

Radioactive black zone in massive gray sandstone of 

Baca Formation. Grab sample, 0.029 percent U.

Yellow-green uranium minerals, associated with carbonaceous material, occur in gray lenticular sandstone at base of Baca Formation. Deposit extends 

along outcrop for about J_ mile and back from outcrop several hundred feet locally. Ore mined from 

open pit, 1954.

Radioactive zone in lower 8 in. of sandstone in Point 

Lookout(?) Sandstone. Sample, 0.022 percent U.

Radioactive zones in two sandstones, separated by 

25-ft stratigraphic interval, in Mesaverde Group. 

Grab sample, 0.022 percent U. Lower zone may be 

stratigraphic equivalent of zone noted above.

Yellow-green uranium minerals associated with carbonaceous material in conglomeratic sandstone 

near base of Baca Formation. Several deposits are 

in vicinity, and this deposit may be extension of 

Red Basin 1. (See above.) Sample of drill cuttings, 

0.40 percent U.

Radioactive zone in Point Lookout(?) Sandstone. 

Sample of drill cuttings, 0.12 percent U.

27_ 2 N. 10 W. Radioactive zone in sandstone in Point Lookout(?) 

Sandstone. Grab sample, 0.14 percent U.

7____ 2 N. 10 W. Radioactive zone in sandstone in Point Lookout(?) 

Sandstone. Grab sample, 0.026 percent U.

G. O. Pachman, E. 

H. Baltz, and R 

L. Gnggs (WC, 

1957}. 

Do.

Do.

Do.

R. L. Griggs (WC, 

1953^.

G. E. Collins (WC,

1954). G. O.

Baclman, E. H.

Baltz, and R. L.

GrigTs (WC,

1957). 

G. O. Pachman, E.

H. Ealtz, and R.

L. Griggs (WC,

1957). 

Do.

Do.
URANIUM DEPOSITS

TABLE 4. Uranium deposits, by county, in northwestern New Mexico Continued

33

Name of deposit

Location

Sec. T. B.

Description of deposit and sample Source of data

Catron County Continued

Unnamed _ _____ CNE# 35_ ____ 2 N.

Do_____ ______ CWtfEtf !!_____ 2 N.

Midnight 2 (£)____ WtfNWtf 12____ 2 N. 

Unnamed__.______ NEtfNEtf 14___ 2 N.

McPhaul adit. ____ CE^E}4 14_____ 2 N.

10W. Radioactive zone in lower 3 in. of sandstone in Point

Lookout(?) Sandstone. Sample, 0.05 percent eU.

Lookout(?) Sandstone. Sandstone contains carbonized fossil logs and thin lenses of carbonaceous 

shale. Yellow uranium mineral occurs on weathered 

faces of carbonaceous shale lenses, where most 

radioactivity detected. Grab sample of carbonaceous shale, 0.33 percent U. Grab sample of sandstone, 0.06 percent U. 

11 W. Tyuyamunite in carbonaceous sandstone of Point 

Lookout(?) Sandstone. U : V ratio about 1 : 2. Ore 

mined in 1957.

11 W. Radioactive carbonaceous zone, about 3 in. thick, in

sandstone at base of Point Lookout (?) Sandstone. 

Selected sample, 0.06 percent U.

11 W. Uranium is concentrated in ferruerinous zone. 1-3 in.

R. L. Griggs (WC

1954). 

G. O. Bachman, E.

H. Baltz, and R. 

L. Griggs (WC, 

1957).

G. O. Bachman, E. 

H. Baltz, and R. 

L. Griggs (WC, 

1957) ; U.S. Bur. 

Mines, amenability 

test no. 418. 

G. O. Bachman, E.

H. Baltz, and R. 

L. Griggs (WC, 

1957). 

McPhaul adit. ___ Do.

Varnum. ___ ___

Mangum_ ____ __

Unnamed_______ _

Do_-_- _ _

Do

Section 18_ _______

Unnamed__ _ ______

Section 2_ ________

Do_ -_-_--_

Do

Section 5____ _ _

Section 6_____ ___

Isabella (42) __ ._

Centennial (77) __

CEJ.EJ. 14_____ 2 N.

NEM 21___ __ 3 N.

22___-_________ 3 N.

"

W^5__. _______ 13 N.

6--____________ 13 N.

SWYt 9 _____ 13 N.

SWJiSWtf 18___ 1ST N.

20andEJ_19(?)_ 13 N.

NW#SE#2_ _ 13 N.

SW#NE# 2__ _ 13 N.

Approx. CW% 2. 13 N.

NE^NE^NEK 13 N.

5.

CNWK6- __ 13 N.

NE# 7 _____ 13 N.

NW#8__. ___ 13 N.

11 W.

16 W.

16 W.

8 W.

8 W.

8 W.

8 W.

8 W.

9 W.

9 W.

9 W.

9 W.

9 W.

9 W.

9 W.

Uranium is concentrated in ferruginous zone, 1-3 in.

thick, at base of Point Look out (?) Sandstone.

Radioactivity is most pronounced where carbonaceous material is concentrated. Deposit is near

axis of small shallow syncline. Sample, 0.04 percent U.

Mineralized sandstone in Mesaverde Group________

Mineralized coaly shale bed about 3 in. thick, 75 ft

below top of Mesaverde Group. Sample, 0.03 percent eU.

McKinley County

Several deposits in Jmw____ _ ____ ______________

do ___ _ _______________

-____do____________--_____--_____-------_---_--_

Deposit in Jmpc. Extends northwestward into sec. 13_

Deposit in Jmw_ ______ _____________________ _ _

Tabular deposit in Jmw _________.-_-__ _ _______

-____do___-_____-_-__--____-___-_---__----------

do

Deposit in sandstone in Jmr. ______ __ ___ _____ _

Tabular deposit, or deposits, probably in Jmpc__ __

Cluster of deposits along north-trending fault in

Jmpc. (Much of ore probably is redistributed.)

Ore mined through vertical shaft, 1959-62.

Tabular, elongate deposit that trends southeastward

in Jmpc. Deposit is at southeastern end of cluster

Do.

Unknown.

R. L. Griggs (WC,

1954).

AEC, DH.

Do.

Do.

For general settingsee Rapaport

(1963, p. 131 and

fig. 1).

AEC, DH.

Sabre-Pinon Corp.,

DH, November

1956.

Do.

Do.

National Lead Co.,

DH, April 1956.

Treasure Uranium

and Resources,

Inc., DH, July

1957.

C. N. Holmes (OC,

January 1959);

AEC; and

Rapaport (1963).

Colamer Corp., DH,

1956.

Section 13_ 

Hogan (39}.

13__________ 13 N. 9 W.

14__________ 13 N. 9 W.

Section 16 _____ SW# 16_____ 13 N. 9 W.

that Includes the Isabella. (See above.) Ore 

mined through vertical shaft, 1958-64.

Several southeastward-trending tabular deposits in 

Jmpc. Deposits extend into SWJ4 sec. 18, T. 13 N., 

R. 8 W. (See above.)

Several medium and small, amoeba-shaped, redistributed deposits in Jmpc. Deposits are concentrated along flank of anticlinal fold and 

parallel to San Mateo fault. Ore produced in 

1959-62.

Several, scattered small deposits in Jmpc____---___-

Calumet and Heclr,,

Inc., DH, May

1957. 

Rapaport (1963, p

131-133 and figs

1 and 6).

Sabre-Pinon Corp. 

DH, August
34 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO 

TABLE 4. Uranium deposits, by county, in northwestern New Mexico Continued

Name of deposit

Location

Sec. T. R.

Description of deposit and sample Source of data

McKinley County Continned

Beacon Hill 

(Gossett) (6).

Poison Canyon 

(66).

Malpais (57)

18 __ 13 N. 9 W.

and 

19.

13 N. 9 W.

20

Mesa Top 7 (Moe; CW^ 20. 

Davenport) (60).

Dog Incline (*7).._

20

Mesa Top 18 and NtfSWtf 20. 

20 (61).

Section 21 (Doris, SW& 21. 

Doris West 

Extension; Doris 

1, Little Doris) 

(81).

13 N 9W

13 N. 9 W.

13 N. 9 W.

13 N. 9 W.

13 N. 9 W.

Marquez (58) ____ 23._______.__ 13 N. 9 W.

Section 24..___ NEJ4 24_____ 13 N. 9 W: 

Chill Wills (19).... NEJ4 24_._... 13 N. 9 W.

Tabular deposit of fracture-controlled redistributed 

material in Jmpc. Ore mined through vertical 

shaft, 1956-60.

Two tabular, stringlike, somewhat discontinuous, 

medium to large deposits in Jmpc. The northern 

deposit extends from outcrop about N. 70° E. for 

about 2,000 ft; the southern deposit from the same 

point of outcrop S. 58° E. about the same distance 

into sec. 20. These deposits mined largely from 

open pits, 1952-62.

Irregular cluster of tabular deposits in Jmpc that 

extend northeastward from Dog Incline workings. 

Locally "stack" ore, concentrated along N. 10° 

W.-trending fractures, as much as 30 ft thick. Ore 

mined in 1958-61 through Dog Incline and Mesa 

Top shaft.

Eastern end of southern part of Poison Canyon deposit that extends into sec. 20. Geology is similar 

to Poison Canyon deposit. (See above.) Ore mined 

through inclined adit, 1957-61.

Irregular cluster of deposits in Jmpc. Deposits are 

largely oxidized redistributed material, partly 

controlled by fracture system that trends about 

N. 15° W. Deposits mined in 1957-64 through 

inclined shaft.

Irregular cluster of tabular deposits between Poison 

Canyon and Dog Incline deposits. Deposits are 

generally elongate eastward in a lower zone and 

irregular in plan and thickness in an upper zone of 

oxidized redistributed material. Deposits are in 

Jmpc. Ore minei in 1954-61 through vertical shaft.

Several somewhat tabular, elongate deposits in Jmpc. 

Two oxidized parallel bodies near base of sandstone, known as Doris and Doris West Extension, 

extend eastward from sec. 20 into sec. 21. These 

bodies, or clusters, are 1,000-1,500 ft long, 10-100 

ft wide, and several feet thick. Near center of sec. 

21 the Doris 1, or Little Doris, consists of several 

small, roughly tabular deposits that are controlled 

by cylindrical collapse structure, which is about 

100 ft in diameter. The center was displaced downward as much as 30 ft probably in pre-Dakota 

time. The ore, which is postfault and partly oxidized, occurs as several scattered pods and thin 

layers, mostly within the cylinder and largely conformable with the bedding, but some also occurs 

outside the structure and some partly along the 

fault and controlled by it. Deposits mined in 

1958-61 through inclined shaft.

Cluster of large and medium elongate deposits in 

Jmpc that trend southeastward and eastward 

through central part of the section. Ore is mostly 

in lower part of sandstone beneath a disconformity 

and generally where sandstone thickness exceeds 

40 ft. Ore-bearing sandstone is fairly clean and contains finely disseminated carbonaceous material, 

in contrast to relatively barren sandstone above 

disconformity which is clayey and contains abundant fragments of coalified wood. Deposits are 

partly oxidized in western part. Ore mined in 

1958-64 through inclined shaft.

Elongate, southeastward-trending deposit in Jmpc. _.

Elongate, southeastward-trending deposit in Jmpc. 

Some ore mined from adjoining sec. 13. Deposit 

mined from shaft, 1960-63.

Holly Uranium Co., 

DH, October 1954; 

and Rapaport 

(1963, p. 126).

Haystack Mountain 

and Development 

Co., June 1955; 

Dpdd (1956); 

Hilp^rt and 

Moench (1960, p. 

454-455); 

Rapaport (1963).

Four Corners Exploration Co., DH, 

October 1958; 

Rapaport (1963) ; 

AEC.

FN, C otober 1958.

Rapaport (1963, p. 

126-129, and figs. 

1 ard4).

Holly Minerals Corp., 

DH, September 

1957. For details, 

see Rapaport 

(1963).

Food Machinery and 

Chemical Corp., 

DH, December 

1955. For details, 

see Granger and 

Santos (1963), and 

Rapaport (196^, 

p. 129-130).

Caluiret and Hecla, 

Inc., DH, May 

1957; Weege 

(1963); Rapaport 

(1963, p. 131 and 

fig. 1).

Rapaport (1963, p.

131 and fig. 1). 

AEC.
URANIUM DEPOSITS 

TABLE 4. Uranium deposits, by county, in northwestern New Mexico Continued

35

Name of deposit

Location

Sec. T. R.

Description of deposit and sample Source of data

McKinley County Continued

Section 24_______ S}_ 24......____ 13 N. 9 W.

Faith (Section 29) E^WJ. 29____ 13 N. 9 W.

Dalco 1 (Barbara EJ.NWJ* 30..__ 13 N. 

J 2) (*).

30-C_____________ SJ_SE#NW#30_ 13 N.

Barbara J 1 (_)____ NWJiNEJ* 30... 13 N.

Barbara J 3 (£?)____ CNJ.NJ.NEJi 13 N.

30. 

Unnamed ______ SJiNEJi 30__. 13 N.

Hanoi (Section 30) SJiSWtf 30- . . 13 N.

Rimrock 13 N.

Flat Top 4_.____ SEJiSEJi 30. . 13 N. 

(Vilatie Hyde)

Section 32_ _______ NWJ£N_WJi 13 N.

32.

Do _______ SWJ£NEJ*32___ 13 N.

Section 32 (#)____ NWJ^NW^SEJ* 13 N. 

32.

Section 33 (Char- SWJ£ 33_ _ __ 13 N. 

lotte) (43).

Section 36______ 36_________ 13 N.

Section 3______ NJS 3______ 13 N.

Section 4______ 4__________ 13 N.

9 W.

Whitecap (61)..... CSJ_NW^ 30___ 13 N. 9 W.

9 W. 

9 W.

9 W. 

9 W. 

9 W.

9 W. 

9 W.

Section 31 (41) N^ 31_________ 13 N. 9 W.

9 W. 

9 W.

9 W. 

9 W.

9 W.

10W. 

10W.

Eastern extension of Marquez deposit and several 

other deposits that extend about S. 70° E. as elongate cluster through southwestern and northeastern parts of section. Geology similar to Marquez deposit. (See above.)

Cluster of medium and small, generally tabular deposits in Todilto Limestone. Cluster trends northward 

and individual deposits are generally elongate 

northward. Cluster is about 2,500 ft long and 100- 

300 ft wide. Deposits worked through vertical 

shaft, 1958-64.

Medium, rather tabular, irregular-shaped deposit 

that is elongate northward. Deposit is generally 

concentrated in middle part of Todilto Limestone. 

Ore worked through vertical shaft, 1957-64.

Medium deposit, elongated northward, and in approximate middle of Todilto Limestone. Deposits 

mined through Dalco 1 shaft, 1959-60.

Medium deposit immediately south of Dalco 1. 

Deposit is irregular in outline and in approximate 

middle of Todilto Limestone.

Medium deposit and one or more small deposits 

nearby in Todilto Limestone. Deposit worked 

through vertical shaft, 1956-57.

Several medium and small deposits in Todilto Limestone. Ore worked through vertical shaft, 1959-63.

Several small and medium deposits in Todilto Limestone.

Several medium and small deposits in middle and 

lower parts of Todilto Limestone. These deposits 

are generally irregular in outline and associated 

with diversely trending intraformational folds in 

the limestone. Deposits generally mined from opencuts, 1952-64.

Medium deposit, similar to Manol deposits (above). 

Ore mined through vertical shaft, 1952-58.

Medium deposit in middle and lower part of Todilto 

Limestone. Is elongate northward. Extends into 

Vilatie Hyde on western side. Deposit mined from 

inclined shaft, 1955-64.

Several medium and small deposits in middle and 

lower parts of Todilto Limestone. Deposits mined 

by opencuts, 1953-62.

Small deposit in Todilto Limestone ________________

Medium deposit and several nearby small deposits 

in middle part of Todilto Limestone.

Medium deposit in lower and middle part of Todilto 

Limestone. Deposits mined in 1964 through inclined shaft.

Small deposit in Todilto Limestone. Ore mined from 

open pit, 1958. Several other small deposits in 

Todilto in vicinity.

Deposit in Jmb__________.

____do__________________.

Deposit or deposits in Jmw.

Calumet and HecJa, 

Inc., DH, May 

1957; Rapapor* 

(1963, fig. 1).

Food Machinery and 

Chemical Co., 

DH, May 1957; 

McLaughlin (1963, 

p. 137, 139, 144, 

145, 147).

Mid-Continent 

Uranium Corp., 

April 1959; McLaughlin (1963, p. 

147).

Four Corners Exploration Co., DH, 

1954-58; MidContinent Uranium 

Corp., DH, April 

1959.

Mid-Continent Uranium Corp., DH, 

April 1957.

Mid-Continent Uranium Corp., DH, 

April 1959. 

Do.

I. J. Rapaport (WC, 

1955).

Four Corners Exp1 oration Co., 1954-58.

Four Corners 

Exploration Co., 

DH, 1954-58.

Four Corners 

Exploration Co., 

DH, 1954-58, and 

Flat Top Mining 

Co., DH, 1958.

Haystack Mountain 

and Development 

Co., DH, August 

1951.

Four Corners 

Exploration Co., 

DH July 1956.

Four Corners 

Exploration Co., 

DH, February 

1957.

Four Corners 

Exploration Co., 

DH; AEG.

Food Machinery and 

Chemical Corp., 

DH, June 1955; 

McLaughlin (19*3, 

p. 147 and fig. 1).

AEG. 

Do. 

Do.
36 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

TABLE 4. Uranium deposits, by county, in northwestern New Mexico Continued

Name of deposit

Location

Sec. T. B.

Description of deposit and sample S nirce of data

McKinley County Continued

Junior (4). _______ NEM 4_________ 13 N.

Pat (Dakota) (64). SEtfNEtf 4_____ 13 N. 

(about 300 ft 

from % cor. 

sees. 3 and 

4).

Section 5 (Westvaco; Febco(?))

Sections 10 and 11_ 10 and 1!__.___ 13 N. 

Sections 12 and 13. 12 and 13__-__- 13 N.

Section 14_ ______

Red Point Lode

14______

SW#SW# 

16.

__ 13 N.

13 N.

Do_

17.

13 N.

Section 18, NE#___ S}_NE# 18.--.- 13 N.

Section 18, 

(Williams and 

Thompson) (32).

18_

Section 18,

(Williams) (83).

18 13 N.

Haystack (Hay- NWM 19 __ .__ 13 N. 

stack Butte; 

Section 19, 

(18).

Section 19, NE# N}_N}_NE# 19__ 13 N.

(34). 

Section 22, NE# _ NE# 22 __ __ 13 N.

Section 23 (38) ____ S}_SE# 23-_-_._ 13 N.

10 W. 

10 W.

5_._.______ 13 N. 10 W.

10W. 

10W.

10W. 

10W.

Section 17 __ ._._. NW# 17___.___ 13 N. 10 W.

10W. 

10 W.

13 N. 10 W.

10 W. 

10 W.

10 W. 

10 W. 

10 W.

Mineralized zone in carbonaceous sandstone near 

base of Dakota Sandstone. Ore mined from opencut, 1953.

Several lenses of dark-gray radioactive material in 

zone about 15 ft thick in upper part of 60- to 80-ftthick sandstone. This sandstone may be at base of 

Jmb or at top of Jmw. The lenses are in buff to 

gray crossbedded sandstone and range in thickness 

from a few inches to about 1 ft. In 1954, the 

workings were four short partly connected adits, all 

within an outcrop distance of about 100 ft. Mined 

in 1952^-63 but most of ore mined since 1958.

Probably in Dakota Sandstone, but some may occur 

in Jmb. Ore was mined from adit, 1958.

Mineralized material in sandstone in Jmb and

possibly in Jmw. 

Mineralized material in sandstone in Jmb and

possibly in Jmw. Locality is near western limit of

Jmpc. Relations of the deposits to Jmpc are not

known. 

Some mineralized sandstone and a few scattered

mineralized fossil logs at outcrop, probably in

Jmpc. 

Small deposit in middle and lower parts of Todilto

Limestone, associated with eastward-trending

intraformational anticlinal fold in limestone.

Deposit mined from open pit, 1952-55. 

Several small deposits in Todilto Limestone_______

Small deposit in Todilto Limestone .

FN, November 1954.

Bob Cat (__)______ NE#NE#(?) 24_ 13 N. 10 W.

Northward extension of several medium deposits 

from SE^ of section and several other scattered 

small deposits in Todilto Limestone.

Cluster of medium and small irregularly shaped 

deposits in Todilto Limestone. Several deposits 

mined from inclined shaft, others from opencuts, 

1952-64.

Cluster of medium and small irregularly shaped 

deposits in Todilto Limestone. Deposits mined 

from open pits, 1953.

Large, irregularly shaped, roughly tabular, partly 

oxidized deposit approximately in middle part of 

Todilto Limestone. Deposit is elongate northward 

and associated with numerous intraformational 

folds in limestone, some of which include the top 

few feet of the Entrada Sandstone These folds 

have diverse trends, but the dominant trends are 

northward and eastward. Ore mined from opencut, 

1952-57.

Several small or medium deposits, near or at outcrop 

of Todilto Limestone. Deposits mined in 1959-64.

Small deposit in Todilto Limestone. Deposit worked 

by open pit, but no shipments reported.

Cluster of small and medium irregularly shaped 

deposits in middle and lower parts of Todilto 

Limestone. Cluster is in elongate zone about 300 ft 

wide that trends eastward along southern margin 

of SE% of section and into adjoining sees. 25 and 

26. Ore mined from opencuts, 1957-58.

Deposit probably in Jmpc. Ore shipped in 1955-___.

AEG. 

AEG, DH.

Mathewson (1953, 

P. 11).

Gabel-nan (1956b, 

p. 394); 

McLaughlin 

(19^3, p. 146).

Food Machinery and 

Chemical Corp., 

DP, July 1955; 

anc1 AEG, DH.

AEC, DH.

Federal Uranium 

Corp., DH, 

June 1956; AEC.

AEC, DH.

FN, July 1955; 

Haystack Mountair and Development Co., DH, 

1955; Gabelman 

(19"6b, p. 393- 

396).

AEC.

McLjrnghlin (1963, 

p. 146).

Haystack Mountain 

and" Development 

Co., DH, June 1951 

anc1 January 1954.

AEC.
URANIUM DEPOSITS 

TABLE 4. Uranium deposits, by county, in northwestern New Mexico Continued

37

Name of deposit

Location

Sec. T. R.

Description of deposit and sample Source of data

McKinley County Continued

Blue Peak 

(Garcia 1) (10).

Divide 25, 26, 27, 

and 28.

Red Rock 3 and 4__

Section 25 (40) __

Hanosh (Section

26) (16). 

Section 36, NE^

(Rimrock) (44). 

Redco _______ _ _

Unnamed. __ ___

Do

Do___ ....

Do

Do

Haystack 2 (17)...

Section 13, SE% 

(Bibo) (31). 

Section 24 (39) _ _ _

Section 31_______

Section 32

(Yucca) 

Green Pick 20____

SEJ4NE}£ 24____ 13 N.

SEtfSWtf and 13 N. 

SWJiSEJi 24.

SEJ4SEJ4 24 13 N.

25__-.__-______ 13 N.

N>.NE^26 ___ 13 N.

EJ-.NEK 36___._ 13 N.

NWKNWJ4 10__ 13 N.

SE^NWK 11 - 13 N.

S>.SE^ 11__.___ 13 N.

SW^SW^ 12___ 13 N.

SW^SE}4 12 __ 13 N.

NEtfNWtf 13__ 13 N.

CSWtf 13____._ 13 N.

SJ_SE^SEJ4 13__ 13 N. 

NEK24________ 13 N.

CWJ. 31_. __ __ 14 N.

E>_SW^ 32 14 N.

4___-__._______ 14 N.

10 W.

10W. 

10 W.

10W.

10 W.

10 W.

11 W.

11 W.

11 W.

11 W.

11 W.

11 W.

11 W.

11 W. 

11 W.

8 W.

8 W.

9 W.

This deposit, or deposits, consists of several medium 

and small, eastward-trending, tabular, lenselike 

layers of gray mineralized material in approximate 

middle of Jmpc. Relatively dense fracture sets in 

ore bodies and oxidized minerals indicate fracture 

control of ore. In 1954, exposed mineralized material ranged in thickness from 0 to about 2 ft 

and had been mined from two principal adits, 

about 600 ft apart at the outcrop. Deposit mined 

intermittently, 1951-64. 

Several small scattered deposits in Todilto Limestonelower part of Todilto Limestone and in two general 

clusters. One cluster trends eastward through 

N}_N}_ of section; other cluster trends southeastward from central part of section into SW% of 

adjoining sec. 30, T. 13 N., R. 9 W. Deposits 

mined mostly from opencuts, 1952-64. 

Medium, irregularly shaped deposit in middle and

lower parts of Todilto Limestone. Is westward 

extension of cluster of deposits in northern part 

of sec. 25 (above). Ore contained local pockets of 

fine-grained fluorite. Ore mined from inclined 

shaft, 1952-57. 

Small deposit at outcrop of Todilto Limestone. Mined

from opencut, 1952-58.

____do __ __ __________________

_ _ _ do _ _ _ ___ _ _

do _ _ _

Cluster of small deposits in middle and lower parts of

Todilto Limestone. Cluster trends northward. 

Deposits mined from opencut, 1956-61.

One or more small to medium deposits in Todilto 

Limestone. Ore mined, 1958-61, from opencut.

opencut, 1952-57.

is extension of deposit in eastern part of sec. 36, 

T. 14 N., R. 9 W. 

Large deposit in one or more tabular layers in upper

part of Jmw.

stone near base of Hosta Tongue of Point Lookout

FN, October 1954; 

Rapaport (1963, 

p. 123-124 and 

fig. 1).

Four Corners 

Exploration Co., 

DH, August 19f 7. 

Do.

Haystack Mountain

and Development 

Co., DH, 1954-56. 

For some detail, 

see McLaughlin 

(1963, p. 146-147).

FN, July 1954.

AEC.

Do.

AEC, DH.

Do.

Do.

Do.

Do.

Haystack Mountain

and Development 

Co., DH, July 

1951. 

Federal Uranium Co., 

DH, June 1956. 

AEC.

Unknown.

E. J. Longyear Co.,

DH, JuneDecember 1958. 

I. J. Rapaport

(WC, 1952).

Section 17_ ____ 

Section 17 (80).

Section 18. 

Section 20.

NJ.17. 

SJ. 17..

18

20.

14 N. 

14 N.

14 N. 

14 N.

9 W. 

9 W.

9 W. 

9 W.

Do._.___.____ SWK20._______ 14 N. 9 W.

Sandstone. Deposit extends about 50 ft along cliff 

face. Sample, 0.10 percent U.

One or more medium and small deposits in Jmw__ _

Several large and medium tabular deposits in upper 

part of Jmw. Worked from vertical shaft in SW^ 

of section, 1960-64. Locally, the deposits are in two 

stratigraphic zones, which extend into parts of adjoining sees. 18 and 20.

Several large and medium tabular deposits in middle 

and upper parts of Jmw. Locally, deposits are in 

two stratigraphic zones.

Several medium deposits in one general zone in upper 

part of Jmw.

Medium to large deposit, or cluster of deposits, in one 

general stratigraphic zone in upper part of Jmw.

AEC, DH.

Kermac Nuclear 

Fuels Corp. DH, 

December 1956; 

AEC, DH,

Do.

Kermac Nuclear 

Fuels Corp., DF, 

May 1957; AEC, 

DH. 

Do.
38 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO 

TABLE 4. Uranium deposits, by county, in northwestern New Mexico Continued

Name of deposit

Location

T. B.

Description of deposit and sample Source of data

McKinley County Continued

Canyon Mulatto_ NW# 24. 

Section 26 (Rio de SWtf 26_.

Oro).

Section 26. 

Section 27.

14 N. 9 W.

14 N. 9 W.

26___- 14 N. 9 W. 

._---. 14 N. 9 W.

Mineralized lens of coaly material, about 3 in. thick, 

at top of Crevasse Canyon Formation. Channel 

sample 1.3 ft long, 0.03 percent IT.

A large deposit or cluster of deposits in upper part of 

Jmw. Deposits occur in three general zones within 

stratigraphic interval of about 75 ft and extend into 

adjoining margins of sees. 27 and 35.

Elongate deposit, probably in upper part of Jmw _

Large, somewhat discontinuous deposit that trends 

southeastward from adjoining sec. 28 and into SE% 

sec. 26. Deposit is in two or more stratigraphic zones 

in upper part of Jmw.

Ann Lee (Section 

28) (3).

28. 14 N. 9 W.

Section 29 (Kermac-TJnited) 

(86).

29.

Section 30 (Kermac-Pacific) 

(87).

30. 14 N. 9 W.

Section 32 (89) __ 32.

Section 33

(Branson) (91).

33

Consists of large elongate pod and 20-30 subparallel 

elongate pods of prefault, "trend-type" material 

that generally trend N. 70° W. through center of 

section in a zone about 1,000 ft wide. Deposits 

occur throughout the Jmw, but generally ascend 

stratigraphically northward and less markedly 

westward. The larger body is markedly elongate 

and is closely related to enclosing channellike 

sandstone unit. Other bodies are also elongate 

and controlled by various stratigraphic features. 

In early 1963, about three-fourths of mine reserves 

had been removed through a vertical shaft.

14 N. 9 W. A very large cluster of deposits and an extension of 

those in adjoining sec. 30. In western part of 

section, geologic relations are similar to those in 

Section 30 (Kermac-Pacific) . In northern part of 

section the deposits are elongate eastward and 

are in the upper part of the Jmw. In southwestern 

part of section the deposits are elongate southeastward and are in the lower part of the Jmw. 

These two elongate parts of the cluster are "trend" 

type ore. During productive period of 1961-64, 

northern part was mined through vertical shaft 

in sec. 30; southern part through vertical shafts 

in sees. 32 and 33.

A very large cluster of irregularly shaped deposits 

which occur in four sandstone units within a 

stratigraphic range nearly 200 ft thick in Jmw. 

The largest and highest grade bodies are in upper 

two sandstone units, are crescent shaped, concave 

northward, and partly confined between two 

parallel north-trending faults. The bodies in two 

lower units are more linear. Both apparently conform to sedimentary structures, but upper zones 

are probably mostly "stack" type ore. These deposits largely occupy east-central part of sec. 30 

and extend eastward into sec. 29 and southwestward through sec. 29 into sec. 32. Ore mined 

through vertical shaft, 1959-64.

A large tabular deposit in lower part of Jmw. Deposit is elongate eastward and locally is multilayered. Ore mined through vertical shaft, 1958-64.

A very large, somewhat discontinuous, elongate 

tabular cluster of deposits that trends about S. 70° 

E. from the northwestern part of section eastward 

into adjoining sec. 34. Deposits are in several 

sandstone units in Jmw and show a general tendency to rise stratigraphically northward. In eastern 

part of section, deposits are offset by northtrending graben. The general geology in this section is similar to that of adjoing sec. 34. Since 

1959, deposits have been mined through a vertical 

shaft.

G. O. IHchman, E.H. 

Bait?,, and R. B. 

O'Sullivan (WC, 

1953).

Rio de Oro Uranium 

Mines, Inc., DH. 

August 1957; 

HazHtt and Kreek 

(1963, fig. 1).

Hazlett and Kreek 

(1963, fig. 1, p. 83).

Kermac Nuclear 

Fuels Corp., DH, 

undr.ted. For general setting see 

Hazlett and Kreek 

(196T).

Phillip^ Petroleum 

Co., DH, December 1957; 

Squares (1963).

Phillips Petroleum 

Co., DH, March 

1958; Clary and 

othe-s (1963); 

AEC.

Kerms R Nuclear 

Fuels Corp., DH, 

August-October 

1956: Clary and 

others (1963).

14 N. 9 W. 

14 N. 9 W.

San Jsointo Petroleum Qorp., 

DH. January 1956.

PhilliF" Petroleum 

Co., DH, March 

195P; Harmon 

and Taylor (1963); 

Hazlett and 

Kreek (1963).
TJRANIUM DEPOSITS 

TABLE 4. Uranium deposits, by county, in northwestern New Mexico Continued

39

Name of deposit

Location

T. R.

Description of deposit and sample Source of data

McKinley County Continued

Sandstone (Section 34. 

34) (75).

14 N. 9 W.

Cliffside (Section SW% 36. 

36) CM).

14 N. 9 W.

Section 36___.._ CE^ 36. 

Sections 2 and 3___ 2 and 3_ 

Section 10 (78).... E^ 10._

Mary 1 (59)....... NW^ 11.

Dysart 1 (Section SW% 11. 

11) (28).

14 N. 

14 N. 

14 N.

14 N. 

14 N.

9 W.

10 W. 

10 W.

10 W. 

10 W.

Dysart 2 11 and 12.

A very large cluster of parallel, elongate, and tabular 

deposits in several sandstone units in Jmw. 

Cluster trends eastward through central part of 

the section into adjoining sees. 33 and 35 and 

generally ascends stratigraphically down dip to 

north. Deposits are directly associated with finely 

disseminated carbonaceous material, follow depositional structures, and generally thicken where 

enclosing sandstone units thicken. A northtrending graben in western part of section displaces ore bodies about 50 ft. No premineral 

faults have been recognized. Ore has been mined 

since 1959 through vertical shaft.

A large, multilayered, irregular, cluster of deposits, 

principally in upper part of Jmw. This cluster is 

eastward extension of the trend of bodies from 

sec. 35. Most of ore is in irregular stacklike mass 

that has a central core 35-40 ft thick and tabular 

bodies that project outward in several zones. At 

southern edge of mass is a cylindrical collapse 

structure about 100 ft in diameter in which core 

is displaced about 20 ft. Ore in core is generally 

higher grade and thicker than in adjacent walls 

but in same stratigraphic zone. Rest of ore in 

smaller elongate bodies that extend to southeast 

and northwest. A 6,000-ton sample of ore averaged 

0.52 percent U3O8, 0.23 percent V2O5, 0.012 percent Mp, and 0.029 percent Se. Body has been 

mined since 1960 through a vertical shaft.

Tabular deposit in upper part of Jmw. Deposit may 

extend into adjoining sec. 31.

Several small deposits, located by wide-spaced drilling, in Jmw.

Large deposit, or cluster of deposits, in one or more 

layers in upper part of Jmw. Cluster is westerly 

extension of Dysart 1. Deposit has been mined 

since 1957 through vertical shaft.

Large deposits in several zones in upper Jmw. Much 

of ore is fracture controlled. Ore has been mined 

since 1959 through a vertical shaft.

A cluster of large and medium deposits in upper part 

of Jmw. Deposits were generally elongate eastward 

through southern part of section and extended into 

adjacent parts of sees. 10 and 12. Host sandstone 

has bedding structures that also generally trend 

eastward and apparently controlled deposits, except for small linear oxidized body that followed a 

northeasterly striking fault. Deposits mined in 

1956-62 through vertical shaft.

Large, irregularly shaped tabular deposit in upper 

sandstone unit of Jmw. Deposit mined through 

vertical shaft in SEK sec. 11, 1959-63.

Section 12_____ E^ 12.. 

Section 13. ____ NEK 13.

Do___._._ S% 13___ 

Bucky (Jeep 6) SE^ 14.

14 N. 10 W.

14 N. 10 W. Small to large deposits in several zones in Jmw______

14 N. 10 W. Several medium, generally multilayered, deposits 

near middle of Jmw.

14 N. 10 W. Large multilayered deposit and several small scattered deposits in upper part of Jmw.

14 N. 10 W. Several small to medium tabular deposits mainly in 

upper Jmw. Since 1959 deposits mined from vertical shaft.

Phillips Petroleuir 

Co., DH, Decerrber 1957; Harm-Hi 

and Taylor 

(1963).

Phillips Petroleun: 

Co., DH, Decenber 1957; Clark 

and Havenstrite 

(1963).

Phillips Petroleum 

Co., DH, December 1957.

Entrada Oil and 

Copper Co., DF, 

undated.

Kermac Nuclear 

Fuels Corp., DF, 

June 1957.

AEC.

Rio de Oro Uranirm 

Mines, Inc., DF, 

May 1957; Crork 

(1963); FN.

Kermac Nuclear 

Fuels Corp., DH, 

November 1956; 

AEC.

Kermac Nuclear 

Fuels Corp., DH, 

November 1956.

Homestake Mining 

Co., DH, November 1957. 

Do.

Holly Minerals 

Corp., DH, 

November 1956.
40 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO 

TABLE 4. Uranium deposits, by county, in northwestern New Mexico Continued

Name of deposit

Location

Sec. T. R.

Description of deposit and sample Scrjrce of data

McKinley County Continued

Section 15 (79}.... SEtf 15___-.--. 14 N. 10 W.

Section 21 ___._. 

Section 22_____. 

Section 22 (82)..

14 N. 10 W.

14 N. 10 W.

14 N. 10 W.

Section 23 (83).... 23............. 14 N. 10 W.

Section 24 (84)---- 24............. 14 N. 10 W.

Section 25 (86)._ 25...___.__ 14 N. 10 W.

Section 26___... 

Section 27_____.

14 N. 10 W. 

14 N. 10 W.

Large multilayered irregularly shaped deposit in 

Jmw. Deposit is about 1,500 ft across and as much 

as 50 ft thick and extends into adjoining sees. 22 

and 23 to south and east. Deposit contains both 

"trend" ore and "stack" ore, the latter localized 

along fractures and oxidized. Ore mined through 

vertical shaft, 1958-64.

Several small scattered deposits in Jmw and lower 

part of Jmb.

Large deposit and several scattered smaller deposits 

in Jmw. The large deposit may be an extension of 

deposit in E>£ sec. 21. (See above.)

Very large cluster of multilayered deposits in Jmw, 

largely concentrated in NE% but extends into 

adjoining quarters and into sees. 15 and 23. The 

continuity of this cluster and its considerable thickness suggests it is principally redistributed, or 

"stack" ore. Since 1958 ore has been mined through 

a vertical shaft.

Very large multilayered deposit, or cluster of deposits, 

principally in the middle of the Jmw. Cluster trends 

eastward across northern part of section, southward across eastern part and into adjoining sees. 

15, 22, 24, and 25. Consists of both "trend" ore 

and "stack" ore, which was deposited updip to 

north of trend ore along fracture system. Since 

1959 deposit has been mined through vertical shaft.

Very large multilayered deposit, or cluster of deposits, 

generally in Jmw, but locally may partly occur 

in lower part of Jmb. Cluster is largely within WJ4, 

but locally extends into EJ^. General geology 

similar to adjoining sees. 23 and 25. Since 1959 

ore has been mined through vertical shaft.

A very large series of lenses and pods in Jmw that 

extends as a linear mass southeastward across sec. 

25 into sees. 23, 24, 26, and 36. Deposits are largely 

"stack" ore, but much trend ore near base of mass. 

Stack ore, some as much as 100 ft thick, is controlled by northwest-trending fracture system. 

Deposits mined since 1959 through vertical shaft.

Large multilayered cluster of deposits in Jmw. This 

is part of cliister described under Section 25 (see 

above).

Small and medium deposits, generally near base and 

middle of Jmw.

Section 28. 

Section 29.

Silver Spur 1 (7)_ 31-.......___.. 14 N. 10 W.

Silver Spur 5 (8)... NEtf 31 ..... 14 N. 10 W.

Small Stake (0)---

28_ 14 N. 10W. Medium deposit, probably in Jmw______-______..

..... 14 N. 10W. One or more deposits, probably in eastern part of

section, in Jmw.

Deposit consists of yellow uranium minerals disseminated in basal sandstone of Dakota Sandstone. 

Carbonized, macerated plant debris is abundant 

and limonite staining conspicuous. Ore mined 

from open pit, 1955-58.

Yellow uranium minerals, including metatyuyamunite (Gruner and others, 1954), disseminated 

in basal sandstone of Dakota Sandstone and apparently in scour-filled channel 1,000-2,000 ft 

wide. Limonite staining is conspicuous and carbonized macerated plant debris is abundant. Consists of stringlike cluster of deposits that are 

individually and collectively elongate N. 25° E. 

and parallel to secondary joint set. Dip of crossbeds is about N. 30° W., and strike of principal 

joint set is about N. 15° W. Ore mined from 

several shallow open pits, 1952-59.

31_____ 14 N. 10 W. Deposit, similar to Silver Spur deposits, occurs in 

scour-filled channel. Ore mined from short adit in 

1952.

Sabre Uranium Co., 

and The American 

Mete.1 Co., Ltd., 

DH, March 1956; 

GouH and others 

(196?).

Kermac Nuclear 

Fuelr Corp., DH, 

June 1957. 

DC.

Kermac Nuclear 

Fuels Corp., DH, 

June 1957. For 

general relations 

see Gould and 

other* (1963).

Sabre-F'non Corp., 

The American 

Metal Co., Ltd., 

and Homestake 

Mining Co., DH. 

March 1956; 

GouH and others 

(196?).

Pacific Uranium 

Mine* Co., DH, 

July 1957.

Sabre-Pinon Corp., 

The American 

Met?' Co., Ltd., 

and Homestake 

Mining Co., DH, 

March 1956; 

GouH and others 

(196D.

Pacific Uranium 

Mines Co., DH, 

July 1957.

Pacific Uranium 

Mines Co., DH, 

October 1956.

AEC.

AEC, DH.

FN, September 1954.

Mirsky, 1953; and 

FN, September 

1954.

Mirsky, 1953; AEC.
URANIUM DEPOSITS 

TABLE 4. Uranium deposits, by county, in northwestern New Mexico Continued

Name of deposit

Location

Sec. T. R.

Description of deposit and sample Source of data

McKinley County Continued

Section36 36.

Section 36 (United NE}£ 36. 

Western)

Section l---_-_.__ NWtf 1

Do_. 

Section 2

Section 4_________ 4_ _-____.

Unnamed_ _ _ _ _ _ E}_W}_ 4.

14 N. 

14 N. 

14 N.

14 N. 

14 N.

14 N. 

14 N.

10W. 

10W. 

11 W.

11 W. 

11 W.

11 W. 

11 W.

Alta (#)---------- NWtfSWtf 5____ 14 N. 11 W.

Francis (38)....... NWtfNWtf 8___ 14 N. 11 W.

Evelyn (34)....... NW# 9________ 14 N. 11 W.

Unnamed

17.

Bottoms.. ________ S)_ 18

14 N. 

14 N.

11 W. 

11 W.

Section 19 (Maddox and Teague)

(36). 

Glover (Private

Property) (14). 

Billy The Kid

(Red Top 1)

(3). 

Section 19 (Greer,

Warren, and

McCormack)

(36). 

Section 21 (37)....

19----________. 14 N. 11 W.

Possibly

20.

14 N. 

14 N.

11 W. 

11 W.

19.

14 N. 11 W.

21_ 14 N. 11 W.

Several scattered deposits in Jmb and in upper part 

of Jmw.

Medium deposit in one or more layers in upper part 

of Jmw. Some ore mined in 1959 through vertical 

shaft.

Deposits in Jmb and possibly in Jmw______________

Multilayered deposits in Jmb_________-__________-

Deposit probably an extension from SWJ4 sec. 1. 

(See above.)

One or more deposits, probably in Jmb and possibly 

in Jmw.

Radioactive anomalies in several wide-spaced drill 

holes. Radioactive zone probably is in upper part 

of Jmb.

Elongate tabular deposit that trends northward 

from the outcrop for more than 300 ft. It is mostly 

near the pinchout of sandstone tongue a few feet 

thick that splits from top of Jmw about 100 ft 

west of mine entry. Top foot or so of host sandstone contains abundant macerated carbonized 

plant fragments. Mineralized zone is immediately 

beneath carbonaceous material in coarser grained 

sandstone that is free of any obvious carbonaceous material. The northern part of deposit might 

be in top of the Jmw. Ore mined from adit, 1951-61.

This deposit, or cluster of deposits, consists of several 

mineralized masses in sandstone lens in upper part 

of Jmb. Lens ranges in thickness from few feet to 

about 80 ft, trends eastward, and intertongues with 

claystone and mudstone. Deposit is near or at outcrop at west end of lens where it is immediately 

beneath Dakota Sandstone, is about 40-50 ft thick, 

and bleached white. Deposit consists of mineralized 

fossil logs and tabular layers in central part of lens. 

Workings consists of rather short tunnel and four 

short adits. Deposit mined in 1953-54.

This deposit is about 3,500 ft east of Francis (see 

above) and in same sandstone lens, where it is 60- 

80 ft thick and limonite stained. Deposit consists of 

several bodies, associated with abundant carbonized and macerated plant debris, mainly in central 

part of lens. Workings consist of main adit, about 

350 ft long, and two short adits, all driven northwestward from outcrop. Outcrop of lens at mine is 

along north-trending east-facing fault scarp in the 

upthrown block of the Bluewater fault. Deposit 

mined in 1953-56.

Yellow uranium minerals show at the outcrop of 

sandstone lens near top of Jrnr.

Radioactive zone about 0.2-0.5 ft thick in Todilto 

Limestone extends along outcrop about 25 ft. 

Sample 0.4 ft thick, 0.07 percent eU3 p8.

One or more small deposits in Todilto Limestone; location uncertain but probably in NEJ4 and NJ.SEJ4. 

Ore mined from opencut, 1953.

Small deposit in Todilto Limestone. Some ore mined 

in 1950.

Small deposit in Todilto Limestone. Some ore mined 

from opencut, 1952-55.

Several small and medium deposits at outcrop of 

Todilto Limestone. One deposit may be in SWJ4 of 

adjoining sec. 18. Deposits mined from opencuts, 

intermittently, 1952-58.

Small deposit in Todilto Limestone immediately 

west of and in footwall of Bluewater fault. Deposit 

mined from opencut, 1953.

San Jacinto Petroleum Co., DH, 

September 1956. 

Do.

Phillips Petroleum 

Co., DH, December 1957. 

Do.

The Superior Oil Co., 

DH, June 1957.

AEG, DH.

Pacific Uranium 

Mines Co., DH, 

June 1956.

FN, and The 

Anaconda Co., 

October 1955.

Do.

Do.

Earl Arlin (OC,

1957). 

M. J. Sheridan

(WC, 1950).

AEG.

Do. 

Do.

Do. 

Do.
42 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO 

TABLE 4. Uranium deposits, by county, in northwestern New Mexico Continued

Name of deposit

Location

Sec. T. R.

Srarceof data

McKinley County Continued

T 2 (45). .........

T 10 (46).. .......

Silver Bit 7 (95)...

Silver Bit 15 (96).. 

Silver Bit 18 (97)..

Eagle. ____ .___ _

Lawrence Elkins 

(20). 

Tom Elkins (48) ...

Last Chance 2 _ __ 

Section 27. _ _

Sections 32-33 

(West Ranch) 

(90). 

Section 35 ___ ___

Section 23 _ _____

Blackjack 1 (8)...

WtfNWJiSWtf 

28.

WJ.NWJ4STO 

28. 

NJ.NEJ* 10_____

SWKNEH 10 _

SEtfNEtflO _ 

10-11 

SWK 18.___.___

SEtfNEtf24____ 

NWKSEJ424 

NJ.NWJU4 _

NW#2________

W>_SE}4 27

NE^ 32 and 

NWtf 13.

NE^35._______

NEKNEH23---

NWSW 12_______

14 N. 

14 N.

14 N. 

14 N. 

14 N.

14 N.

14 N. 

14 N.

14 N. 

14 N.

14 N. 

15 N. 

15 N. 

15 N.

15 N. 

15 N.

11 W. 

11 W. 

12 W. 

12 W. 

12 W.

12 W.

12 W. 

12 W.

12 W. 

13 W.

14 W. 

11 W. 

11 W. 

11 W.

12 W. 

13 W.

Small deposit in upper part of Todilto Limestone. 

Ore mined from open pit, 1952. 

Probably an extension of T 2 deposit into T 10 

claim. Deposit mined from open pit, 1952. 

Deposit at top of Jmw. Deposit probably worked as 

small opencut, 1955-57. 

One or more deposits at top of Jmw. Ore worked as 

opencuts, 1955-57. 

One or more deposits probably at top of Jmb and 

possibly in base of Dakota Sandstone. Ore probably mined from opencut, 1955-57. 

Yellow uranium minerals in sandstone near top of 

Jmr. 

Small deposit in Todilto Limestone ____ ____ ______

Small deposit in Todilto Limestone. Some ore possibly mined in 1954. 

Small deposit in Todilto Limestone. Deposit mined 

in 1954-55. 

Yellow uranium mineral shows in spots in bedding 

along outcrop of Todilto Limestone.

Spotty, yellow uranium minerals show in sandstone 

near top of Jmr. Channel sample, 0.02 percent 

eU3 08 .

Geology unknown. Deposit 260 ft below surface, probably in Jmw. Deposit mined through inclined 

shaft, 1960-64. 

Deposit or cluster of deposits in Morrison Formation.

A verv large, V-shaped, complex deposit in upper part

AEC. 

Do.

C. K. Presley (WC, 

1955). 

Do.

Eo.

Earl Arlin (OC, 

1957). 

AEC. 

Do.

Do.

R. H. Olson, and 

J. P. Hadfield, 

Jr. (WC, 1957). 

J. P. Hadfield and 

R. H. Olson (WC, 

1951). 

Pacific Uranium 

Mires Co., DH, 

November 1956. 

AEC.

Phillips Petroleum 

Co., DH, November 1957. 

Tidew?.ter Oil Co., 

DH, October 1958. 

MacRae (1963) ; AEC.

Section 13._____. 

Black Jack" 2~(9)~.~.

NEHNEK13.

15 N 13 W.

of Jmw. North arm of V trends east, is about 150 ft 

wide and 3,600 ft long, apparently follows sedimentary structures, and is prefault. From apex of 

V at east end of north arm, other arm extends southward about 3,000 ft and is about 200 ft wide. It 

is relatively thick and apparently is postfault, as it 

is oxidized and controlled, at least in part, by 

north- and northeast-trending fractures. Deposit 

mined through vertical shaft, 1959-64. 

Deposit in sandstone in Jmw_ __________________

15 N. 

15 N.

13 W. 

13 W.

.do.

Section 21._______ W#NWJi21____ 15 N. 13 W.

Several large irregularly shaped ore bodies in sandstone 

18-60 ft thick near base of Jmb. Best ore occurs 

where sandstone is gray, crossbedded, and coarse 

grained; it contains mudstone splits and finely disseminated carbonaceous material. Ore pods are 

unoxidized (and probably prefault) and controlled 

by sedimentary structures, which trend southeastward. Main ore cluster is about 200-800 ft wide 

and 3,000 ft long. Small mineralized pods occur 

along same trend southeast and northwest of main 

deposits. Mined through vertical shaft, 1959-64.

Deposit in sandstone in lower part of Jmb-_________

Tidewater Oil Co., 

DH, October 1958.

lo. 

Hoskns (1963); AEC.

Nicholson-Brown 

Santa Fe Christ

S}_ 26 __ 

SWJ4 3.

15 N. 

15 N.

14 W. 

16 W.

Deposit in Jmw--------------------------------

Deposit in carbonaceous shale at base of Dakota 

Sandstone. Ore mined in 1957-58.

Tidewater Oil Co.,

DH, October 1958. 

AEC, DH. 

AEC.
URANIUM DEPOSITS 

TABLE 4. Uranium deposits, by county, in northwestern New Mexico Continued

43

Name of deposit

Location

Sec. T. R.

Description of deposit and sample Source of data

McKinley County Continued

Christian (U 

mine) (#).

4_________ 15 N. 16 W.

Foutz 1 (&?)_______ NWtfNW#4 15 N. 16 W.

Foutz 2 (30)______ NE}4NE}i 5____ 15 N. 16 W.

Westwater 1 (100). S}£ 2___________ 15 N. 16 W.

Becenti (1)._____ NW}i 28 15 N. 17 W.

Diamond 2 (Largo NW#NE# 33_._ 15 N. 17 W. 

2) (3).

Hogback 3 (I?) and N~E% 12. 

4(3).

15 N. 18 W.

This cluster of deposits occurs in Christian 9 and 16 

claims in carbonaceous zone about 15^-20 ft above 

base of Dakota Sandstone and, as indicated by 

Mirsky (1953, fig. 3), in a scour-filled channel. Zone 

is composed of fine-grained crenulated limonitestained gray sandstone that contains thin seams of 

carbonaceous shale and macerated carbonized 

plant debris. Tyuyamunite identified where 

uranium is more concentrated, and the concentration shows a direct relation to the abundance 

of carbonaceous material. Principal working is 

500-ft adit driven northeastward in Christian 16 

claim. In adit near face, mineralized zone is 3-5 ft 

thick. Deposits mined in 1953-55 from Christian 

16 and in 1957-58 from Christian 9.

Deposit in sandstone in Jmw. Ore mined from shallow 

pit at outcrop, 1953.

Deposit in sandstone in Jmw. Deposit mined from 

south-trending adit, 1953.

Deposit in upper part of Jmw. Ore mined in 1957-58..

Deposit occurs in upper part of 10- to 15-ft thick 

sandstone at base of Dakota Sandstone and overlain by lens of carbonaceous shale. Host sandstone 

makes up scour-filled channel in which crossbeds 

dip about N. 30° E. Sandstone is limonite stained 

and contains seams and small pockets of carbonized 

plant material. Yellow uranium minerals including 

meta-autunite, metatyuyamunite, and uranophane 

(Gruner and others, 1954) are disseminated in 

sandstone as well as along joint and bedding surfaces. Joint sets trend N. 50° E. and N. 15° W. 

Ore mined from an open pit, 1952-58.

Two medium to large deposits and several satellites, 

mostly in basal medium- to coarse-grained sandstone unit of Dakota Sandstone. Unit fills channel 

or channels scoured in Jmw. Is overlain by carbonaceous shale and interbedded fine-grained sandstone. Beds strike N. 30° W., dip about 30° SW. 

Two main deposits about 750 ft apart along strike. 

Strike length of north body about 300 ft and south 

body about 500 ft. Bodies pinch out along 500 level 

about 275 ft vertically below mine entry at outcrop. Ore occurred in podlike masses, generally 

crudely elongate with dip of beds and crudely 

parallel to axes of cross folds and to plunge of 

slumplike structures in host sandstone. Ore 

minerals uraninite, possibly coffinite, metatyuyamunite, probably tyuyamunite, and carnotite, 

associated with corvusite, limonite, jarosite, and a 

little marcasite and closely associated with carbonaceous debris. In south body much oxidation above 

450 level and some between 450 and 500 level. 

Mine yielded about 50,000 tons of ore, 1953-64, 

that had U:V ratio of 3:1 and lime content of 0.5 

percent.

Deposit occurs in a carbonaceous coaly shale of 

Dakota Sandstone. Shale is lenticular and locally 

several feet thick and occupies same stratigraphic 

position as shale that overlies Becenti and Diamond 

2 deposits (above). No uranium minerals are apparent except in spots in underlying sandstone 

which under the deposit ranges from 4 to 11 ft in 

thickness. Deposit apparently is related to thick 

part of carbonaceous shale, which thins away 

from vicinity of deposit, and possibly to underlying 

channel-type sandstone (Mirsky, 1953, p. 15). 

Deposit was mined, 1952-60, from open pit and 

prospected at southern end by 400-ft incline 

shaft.

Mirsky (1953); FF, 

October 1955; 

U.S. Bur. Mines 

amenability teirt 

report no. 437; 

R. K. Pitman (OC, 

1965).

FN, October 1955;

Sharp (1955, p. 9). 

FN, October 195<>.

AEC.

FN, October 1955; 

and Gabelman 

(1956a, p. 315- 

316).

Mirsky, 1953;

Gruner and others, 

1954, p. 37; FN, 

October 1954; 

Gabelman, 195fa, 

p. 312-316; Four 

Corners Uraniu-n 

Corp., January 

1959; Chico, 1959.

FN, October 1954; 

Gabelman (1956a, 

p. 307-308); 

Mirsky (1953).

329-381'
44 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

TABLE 4. Uranium deposits, by county, in northwestern New Mexico Continued

Name of deposit

Location

Sec. T. R.

Description of deposit and sample Source of data

McKinley County Continued

Unnamed______ NEJi 32______ 16 N. 12 W.

Section 21_____._- SWK 21_____ 16 N. 

Section 8____-____ SEK 8___._____ 16 N.

Section 9____.__ SE#9_______ 16 N. 

Section 16._____ NJ_NWJ£ 16_.__ 16 N.

Do......

Church Rock

.. NWtfSWtf 16 16 N. 

I. NEK 17..______ 16 N.

Section 17.._._... WJ_ 17.._______ 16 N.

Section 18.__...._ NWtf 18.____ 16 N.

Do....._..._. SWtf 18 _ 16 N.

Section 19._______ NW}i 19.______ 16 N.

Section 20._______ 20________ 16 N.

Section 22._______ 22__.__._______ 16 N.

Section 23._______ NWJiNEJ* 23_ 16 N.

Foutz 3 (Yellow 

Jacket; 3YJ)

(37).

Section 14__ ____ NWK 14- ____ 16 N. 

Section 24. ....... NE% 24 _ _____ 16 N.

CD and S (Section SE^ 35.-.. 16 N.

35) (13). 

Delter_____ ....... NWX 36. ______ 16 N.

Car-Ball 13_. ...... NEK 26........ 16 N.

Dalton Pass....... *28__ _______ 17 N.

15 W.

16 W.

16 W. 

16 W.

16 W. 

16 W.

16 W. 

16 W. 

16 W. 

16 W.

16 W. 

16 W. 

16 W.

SEKSEX31___. 16 N. 16 W.

Prospect 2....._ 34_____________ 16 N. 16 W.

Section 13_____ SJ_ 13___.__ 16 N. 17 W.

17 W. 

17 W. 

17 W.

17 W.

18 W. 

14 W.

Radioactive zone at the top of 3-ft coal bed at top 

of Crevasse Canyon Formation and immediately 

beneath Hosta Tongue of Point Lookout Sandstone. Channel sample of upper foot of coal bed 

0.019 percent U.

Deposit in sandstone in Jmb_--_----___-----------

Deposits in lower part of Jmb and upper part of Jmw__

Probably similar to Section 8 (above) _. 

Deposits in Jmb or upper part of Jmw.

Deposit in upper part of Jmw________________--__..

Cluster of deposits in Jmb and Jmw. Deposits mined 

through vertical shaft, 1960-62.

Deposit at top of Jmw.__________________________

Deposit probably in upper part of Jmw.___________

Deposit at top of Jmw__._______--______--.--_-_.

Deposit probably similar to those in adjoining sec. 18

(above). 

Deposit, or cluster of deposits, probably in Jmw____.

Deposit, probably in Jmw._______________________

No information available._____________-__----___.

Tabular, elongate deposit near and at outcrop of 25- 

ft-thick sandstone in Jmb. The deposit is about 250 

ft long, 10-100 ft wide, and averages about 3 ft in 

thickness. It was controlled in part by set of nearvertical fractures that trend about N. 30° W. Host 

sandstone is bounded by claystone units, is poorly 

sorted, crossbedded, clayey, and lacks any 

obvious carbonaceous material. Except for local 

spots of canary yellow oxide, uranium minerals 

are inconspicuous. Ore body was within a lightbrown limonite-stained zone which in turn was 

within a purple hematitic envelope. These zones 

all within light-gray sandstone. U:V ratio about 

1:1. Workings consist of four interconnected adits 

and two small stopes, the floors of which are about 

20 ft apart vertically. Deposit was mined where 

fractures were concentrated, 1954-55.

Radioactive zone in 3-ft-thick sandstone in upper 

part of Jmr. Sandstone is fractured and contains 

much carbonized plant debris. Grab sample, 0.08 

percent eUaOg.

Deposits in Jmw________________________________

No information available..----------------

Deposit probably in Jmw _______________

Deposit in Jmw. Ore mined at outcrop, 1957.

G. O. Fachman, 

E. H. Baltz, and 

R. B O'Sullivan 

(WC, 1953).

Tidewater Oil Co., 

DH, October

1958.

Phillips Petroleum 

Co., DH, January

1959. 

Do.

Tidewater Oil Co., 

DH, December

1958. 

Do.

Phillips Petroleum 

Co., DH, January

1959. 

Do. 

Do. 

DC. 

DC

Unknown. 

Unknown, DH. 

Phillipg Petroleum

Co., DH, January

1959. 

FN, September 1954,

October 1955.

Carnotite impregnates lowermost 2-ft-thick sandstone of Dakota Sandstone. The bed constitutes 

basal part of a sandstone, shale, and conglomerate 

sequence that fills stream channel scoured in Jmw. 

Channel is 200 ft wide and 30 ft deep and trends 

N. 30° E. Host bed is carbonaceous and capped by 

lens of carbonaceous shale.

Radioactive zone about 1.5 ft thick in carbonaceous 

shale near base of Crevasse Canyon Formation. 

Channel sample 4 in. thick, 0.21 percent eU3O8.

Radioactive impure coal bed about 3 in. thick at top 

of Crevasse Canyon Formation and immediately 

beneath Hosta Tongue of Point Lookout Sandstone. Sample 0.2 ft thick, 0.025 percent U.

D. E. Ma thews on

and F. R.

Fincher (WC,

1953). 

Phillips1 Petroleum

Co., DH,

January 1959.

Do.

AEC, DH. 

Do.

Gabehran (1956a, 

p. 316, and fig. 

104).

P. E. Melancon and 

E. B. Butts (WC, 

1953).

G. O. Bachman, 

E. H. Baltz, and 

R. B O'Sullivan 

(WC, March 

1953^.
URANIUM DEPOSITS 

TABLE 4. Uranium deposits, by county, in northwestern New Mexico Continued

45

Name of deposit

Location

Sec. T. B.

Description of deposit and sample Source of data

Rio Arriba County

RA1..._____.._.. SEtfNWtf 11_~ 21 N. 2 E.

Saint Jude______ NEtfSEtf 11_- 21 N. 2 E.

RA2_____________ 11. 21 N. 2 E.

Unnamed______ 14._____._ 21 N. 2 E.

Erma 1. SE>U4._______ 21 N. 2E.

Lucky Strike NE}£NE}i !._._ 22 N. 2 E. 

(Mid-Continent 

1).

Lola___._________ 34_________.___ 22 N. 2 E.

Herrera. 22 N. 3E.

Hillfoot 1 (Serrano NEtfNWJi 8____ 22 N. 3 E. 

prospect) (1).

Red Head 2 (3)_ NEtfSWtfNEJi 22 N. 3 E.

Red Bird (Coyote SWtfNEtf 8_.__ 22 N. 3 E. 

HiU 2) (*).

Rey. Ej_NW>iNE>i 22 N. 3 E. 

27.

Lou______________ WJ_NE#27-___ 22 N. 3 E.

Jaramillo-Montoya_. NW% 4________ 22 N. 4 E.

Radioactive zone in bleached, arkosic, and coarsegrained sandstone of Cutler Formation. Zone is 

few inches thick and concentrated where sandstone contains abundant carbonized plant fragments. Azurite and malachite are present but 

uranium minerals are not visible. Sample from 

dump of prospect pit, 0.07 percent U. 

Radioactive zone about 2-3 ft thick at base of 30- 

ft-thick bleached sandstone of Cutler Formation. 

Zone contains abundant carbonized plant debris, 

shows malachite and azurite, but no visible 

uranium minerals. Numerous small scattered 

deposits are exposed in general area in prospect 

pits and trenches. Channel sample, 0.09 percent 

U3Og.

Similar to RA 1 (above). Deposit is near old caved 

prospect shaft, reportedly worked for copper 

before World War I. Sample, 0.023 percent U. 

Numerous other geologically similar deposits 

occur in general vicinity.

Small deposit in arkosic sandstone of Cutler Formation. Sandstone contains carbonized plant fragments and copper carbonates. Sample of 2-ft 

thickness of sandstone in shallow prospect pit, 

0.05 percent U.

Radioactive zone in gray sandstone of Cutler Formation. Zone contains carbonized plant debris and 

copper carbonates and shows radioactivity over 

area about 20-ft square. Grab sample, 0.20 percent eUsOg.

Radioactive zone in sequence of thin-bedded sandstone, siltstone, and clay in upper part of Cutler 

Formation. Colors are reddish purple, pale brown, 

and gray; no visible uranium minerals; highest 

radioactive readings roughly 0.20 percent eUaOf.

Several small deposits in copper-bearing carbonaceous 

sandstone of Cutler Formation. Uranium is associated with carbonaceous material. Sample, 0.07 

percent U.

Small deposit in sandstone in lower part of Cutler 

Formation.

One or more small deposits at base of conglomeratic 

sandstone in lower part of Cutler Formation. Base 

of the sandstone is in channel scours in underlying 

siltstone. Mineralized zone is ferruginous, contains 

clay galls, and is spotted with copper carbonates 

but no visible uranium minerals. Some ore mined 

from short adit and open cut in 1954.

Small deposit in arkosic sandstone in lower part of 

Cutler Formation, in setting similar to Hillfoot 

and Herrera deposits all being in same sandstone (see above). Some ore mined from opencut 

in 1955.

Small deposit in same sandstone of Cutler Formation as Red Head 2. Yellow uranium minerals 

locally visible and disseminated in sandstone with 

sparse copper carbonates where sandstone locally 

ferruginous and gray. Some ore mined from 50-ft 

adit in 1954.

Small deposit at outcrop in middle of Todilto Limestone. Deposit is associated with intraformational 

folds of several feet amplitude. Limestone in 

vicinity is 10-15 ft thick but about 20 ft thick 

where folds and deposit occur. Prospected by drill 

holes and opencut. Channel sample, 0.02 percent 

UsOg.

Similar to Rey deposit (above)______________---_-

Reported as mineralized Todilto Limestone_________

FN, October 1955.

W. L. Chenowith 

(WC, 1956).

FN, October 1955.

Baltz (1955, p. 11).

H. G. Brown III 

(WC, 1954).

FN, October 1955.

L. J. Reynolds 

(OC, 1955).

Ross Martinez (OC,

1955). 

W. L. Chenowith

(WC, 1956); AE^.

FN, October 1955; 

AEC.

W. L. Chenowith 

(WC, 1957); AEC; 

FN, October 1955.

Ross Martinez anc1 

E. J. Reynolds 

(OC, 1955); FN, 

October 1955; 

R. K. Nestler ard 

others (WC, 

1955). 

Do.

W. L. Chenowith 

(WC, 1956).
46 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO 

TABLE 4. Uranium deposits, by county, in northwestern New Mexico Continued

Name of deposit

Location

Sec. T. R.

Description of deposit and sample Soiree of data

Rio Arriba County Continued

State lease (Little 

prospect).

Corral 3.

16 23 N. 1 W.

Corral 1.

25.

E and B 1.

29.

E and B 3.

25_ . _ _ 23 N 1 W.

23 N. 1 W.

23 N. 1 E.

23 N. 1 E.

29.

TJBD !___....... S#SW^29_.__. 23 N. IE

Whiteflo

Yellow Bird 2. 

Pajarito AzuL.

MesaAlta

Resurrection 

(Blackhorse 3).

Wasson (Box 

Canyon) (50).

30__ 23 N. IE.

30.... 23 N. 1 E.

31_ 23 N. 1 E.

NW^ 19_-..-_. 23 N. 3 E.

31--__. 23 N. 3 E.

28__. 23 N. 4 E.

Unnamed_____ 36________ 24 N. 1 W.

Green uranium minerals (autunite?) occur along H. G. Brown III 

bedding and fracture surfaces of gray mudstone (WC, 1954). 

in San Jose Formation. Grab sample, 0.12 percent 

U808 .

Uraniferous zone in gray medium-grained arkosic Unkno-yn. 

sandstone in Cutler Formation. Sandstone contains gray mudstone galls, carbonized plant 

debris, and some copper carbonate but no visible 

uranium minerals. Rocks are faulted and dip about 

25° N. Some material mined. Sample, 0.03 percent UjOg.

Yellow uranium minerals and copper carbonates H. G. Brown III 

impregnate and form halo around a fossil log in (WC, 1955). 

red medium-grained arkosic sandstone in upper 

part of Cut-er Formation.

Yellow uranium mineral impregnates light-gray Do. 

coarse-gra'ned arkosic sandstone in middle part of 

Cutler Formation. Maximum thickness of mineralized zone is 4 ft and length along outcrop is 30 ft.

Mineralized carbonized log, 0.35 ft in diameter and Do.

2 ft long, in bufif fine-grained arkosic sandstone in

nrddle part of Cutler Formation. Sample of log,

0.25 percent U3O8 . 

Radioactive zone in light-gray arkosic sandstone in Do.

lower part of Cutler Formation. Zone contains

abundant gray mudstone galls, some macerated

carbonized plant fragments, limonite stains, and

some visible copper carbonates. Radioactivity is

between two steeply dipping fractures in sandstone. No uranium minerals are visible. Sample,

0.15 percent UjOg. 

A yellow uranium mineral impregnates light-gray and

red arkose, siltstone, and mudstone along small

channel scours in Cutler Formation. Some carbonized plant debris and copper carbonates visible.

Some material mined from bulldozer cut. 

An 18-in.-thick radioactive zone in middle of 3-ftthick light-gray coarse-grained arkosic sandstone

in lower part of Cutler Formation. 

A radioactive zone in a coarse-grained, light-gray

arkosic sandstone in upper arkosic member of

Madera Limestone. Zone contains some carbonized

plant debris and copper carbonates and questionable visible uranium minerals. 

Breccia pod at top of Todilto Limestone at contact

between gypsum and overlying sandstone of Morrison Formation. (This sandstone is probably in

Summerville(?) Formation.) Pod consists of

limonite-stained limestone fragments, is 5 ft long,

3 ft wide, and 0-10 in. thick. Sample, 0.37 percent

U808 . 

A series of small deposits in zone a few feet thick in

red-brown siltstone in upper part of Cutler Formation. No uranium minerals visible, but spots of

copper carbonates show locally in mineralized

zone for a distance of about 400 ft. Grab sample,

0.02 percent eU8O8 . 

Tabular, lenticular, mineralized zone in Todilto

Limestone on small intraformational fold. Fold

has amplitude of several feet and width of

25-30 ft and according to Chenowith extends into

base of overlying Morrison Formation. (The

Summerville(?) Formation probably overlies the

Todilto Limestone at this locality.) Fold axis may

trend southeast. Limestone is 10-15 ft thick.

Small tonnage of low-grade ore mined from shallow

opencut, 1957. U:V ratio about 1:1. 

Radioactive zone in limonite-stained carbonaceous AEC.

sandstone of Nacimiento Formation. Sample,

0.02 percent U8O8 .

Do.

Do. 

Do.

W. L. Chenowith 

(WC, 1956).

W.L. Oienowith 

(WC, 1957).

W. L. Chenowith 

(WC, 1956); FN, 

Oct. 1955; AEC.
URANIUM DEPOSITS

TABLE 4. Uranium deposits, by county, in northwestern New Mexico Continued

47

Name of deposit

Location

Sec. T. R.

Description of deposit and sample Source of data

Rio Arriba County Continued

Pivot Rock.______ SW^4_________ 24 N. 3 E.

Trejo and Sanches *30 and 31 (?)___ 24 N. 6 E. 

1.

Carbon and Log NJ_NEtf 11_.___ 25 N. 1 W. 

claims.

Young prospect._ 19_____________ 25 N. 1 W.

Coy claims........ NEtfSWtf 30... 25 N. 1 E.

EIC-Band SE% 7_________ 25 N. 2 E.

Maxine.

Alex___._________ N}_31_._______ 25 N. 3 E.

Hornet...._______ NWtf 20_______ 25 N. 5 E.

Lucky Dog 

(Onego?).

29. 25 N. 5 E.

Horny Toad....__ N/2 32__.______ 25 N. 5 E.

Vargas-Jaramillo_ 11 (200 ft east 25 N. 8 E.

of State

Highway 111).

Heart 3-_...._..._ SW^ 26 _____ 26 N. 2 E.

Cebolla 2..._.._._ NW^SW^ 26_ 26 N. 2 E.

Beryl prospect Possibly NEM 26 N. 8 E. 

(Lonesome NWJ4 1. 

deposit (?)).

Pino Verde__.... SWtfNWJi 18_ 26 N. 9 E. 

Rancho AAA____ 10_________ 27 N. 8 E.

Kiawa__________ W>_ H 27 N. 8 E.

North Star_____... SWJflSWJi 31.__ 27 N. 9 E.

Thin spotty radioactive zones in lower part of SaHtral Shale Tongue and top of Agua Zarca Sandstone Member of Chinle Formation. Zones are 

principally in mudstone and conglomerate and 

associated with carbonized logs and plant debris 

but are also in thin limestone lenses. Zones are 

exposed in bulldozed trenches within area about 

100 ft wide and 250 ft long. Sample, 0.05 percent 

eU808 .

Radioactive zone in 3-ft-thick sandstone bed (probably in Poleo Sandstone Lentil of the Chinle Formation). Radioactive zone contains carbonaceous 

seams, malachite, and chalcocite; it extends continuously along outcrop for about 100 ft and discontinuously for about 2,000 ft. Channel sample, 

0.18 percent U8O? .

Radioactive zones in limonite-stained carbonaceous 

sandstone and in carbonized logs of San Jose Formation. Grab sample of log, 0.20 percent UaOg.

Radioactive zone in limonite-stained carbonaceous 

sandstone of San Jose Formation. Sample, 0.04 

percent U«O8 .

Radioactive zone in limonite-stained carbonaceous 

sandstone in talus block of San Jose Formation. 

Grab sample of float, 0.04 percent UjOg.

Radioactive fossil bones occur in wide area at outcrop 

of lower part of Morrison Formation.

Float fragments (some possibly in place) of Todilto 

Limestone range from 0.1 to 3.0 percent U.

Radioactive zone and some carnotite exposed in prospect pits, probably in sandstone at top of Morrison 

Formation.

Yellow uranium minerals exposed along strike of 

beds at outcrop for about 300 ft, in white limonitestained sandstone at top of Morrison Formation. 

Uranium minerals appear to follow fractures that 

strike N. 60° W. and N. 5°-20° E. Channel sample, 

0.40 percent U«O8 .

Similar to Lucky Dog (above)__._________________

Deposit in 2-ft-thick tuffaceous sandstone in Santa 

Fe Group. Conspicuous but spotty yellow and 

green uranium minerals can be traced along 

strike about 500 ft. Siltstone sample, 0.18 percent 

eU3O8 .

Radioactive limonite-stained sandstone immediately 

overlying gypsum unit of Todilto Limestone. 

(This sandstone is probably the Summerville(?) 

Formation.) Grab sample, 0.07 percent eU.

Radioactive fossil bones or bone fragments in sandstone of Morrison Formation. Bone sample, 0.37 

percent eU.

A pegmatite body that contains albite, green microcline, quartz, mica, perthite, green beryl, columbite-tantalates, samarskite, uraninite, gummite, 

and monazite. This may be the Lonesome deposit 

(SWtfSWtf sec. 36, T. 27 N., R. 8 E.).

A microcline-quartz pegmatite dike that contains 

garnet, green fluorite, columbite, samarskite, 

monazite, uraninite, and bismutite at east end.

A crystal of uraninite reportedly obtained in this 

general vicinity (possibily from uraniferous quartz 

vein). Grab sample of Ortega Quartzite of Just 

(1937) assayed 0.03 percent U3O? .

Samarskite, magnetite, and bismutite occur along 

fractures in massive quartz in long, thin, microcline-quartz pegmatite dike.

A long, sinuous, quartz-microcline pegmatite dike 

locally contains columbite, samarskite, monazite, 

and purple fluorite in albite-rich parts. Bismutite 

and samarskite are present in places along the 

quartz core of dike.

P. H. Knowles and 

W. L. Chenowitl 

(WC, 1956).

H. G. Brown III 

and L. L. Werts 

(WC, 1954).

W. L. Chenowith 

and L. R. Kittle - 

man (WC, 1956). 

AEG.

W. L. Chenowith 

and L. R. Kittleman (WC, 1956).

R. K. Nestler and 

L. R. Kittleman 

(WC, 1955).

L. J. Reynolds 

(WC, 1955).

Unknown.

H. G. Brown III 

(WC, 1954).

Do.

G. E. Collins and 

C. T. Butler 

(WC, 1956).

P. E. Melancon 

(WC, 1952).

Do.

Just (1937, p. 67); 

Jahns (1946, p. 

137-143).

Jahns (1946, p. 

183-185).

P. E. Melancon and 

F. R. Fincher 

(WC, 1952).

Jahns (1946, p. 

106-115).

Jahns (1946, p. 

144-146).
48 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO 

TABLE 4. Uranium deposits, by county, in northwestern New Mexico Continued

Location

Sec. T. R.

Rio Arriba Connty Continued

Tusas____ _____

JOL (Royal) ______

NEW 24 and

NWW 18 (uncertain) .

NJ4 24 (uncertain).

28 N.

28 N.

7 and

8 E.

7E.

Autunite, torbernite, and sabugalite are disseminated

in Petaca Schist of Just (1937) along walls of crosscutting purple fluorite veins. Sample, 0.05 percent

U308 .

Geology similar to Tusas deposit (above). Sample,

0.05 percent U3O8 .

AEC.

Do.

Sandoval Connty

Dory (Doric;

Doerrie)

B and G _____ _

Brookhaven___ ___

Unnamed (Base

Metals)

Unnamed. _ __ _ _

Do

Mimi 4_____ _ ___

Unnamed__ _______

We Hope 4 __ ___

N. Blackshere

Ranch.

Blackshere. _____ _

Unnamed.______ _

Do

Do _ ________

Do _ ________

Do _ ________

Do_ _

Do

Do

Do _ ________

Do _ ______ _

Morris-Peters_

Do _ .___._-_

Do

Burcar_ ______ ___

Collins (*«) _______

Section 25___.__ _

*NEW.7 _____

SWK15-__--._

SWJU6 

*NEW !________

NEW 13

*Approx.

CWJ.

12.

NEW 4

*E}_ 25

NWWSWWNWW4______

S}4 6 (uncertain).

10

8 and 9

SEJ4 9

10 and 11 __ __

SEW 11___ _ __

SEW 11--------

SEW 14

NEX 15~_ _______

SE}£21__ _____

SEW22_ __ _ _

SEW23___-.___

17. 

20 ___ ___ _ __

21

*NEWNEW 12

*25

*NWX25______

12 N.

12 N.

12 N.

12 N.

12 N.

12 N.

12 N.

13 N.

13 N.

13 N.

14 N.

15 N.

15 N.

15 N.

15 N.

15 N.

15 N.

15 N.

15 N.

15 N.

15 N.

15 N.

15. N.

15 N.

17 N.

17 N.

17 N.

3 W.

3 W.

3 W.

4 W.

4 W.

4 W.

6 E.

4W.

6 E.

6 E.

6 E.

1 W.

1 W.

1 W.

1 W.

1 W.

1 W.

1 W.

1 W.

1 W.

1 W.

1 E.

1 E.

1 E.

1 W.

1 W.

1 W.

Small pod of mineralized, carbonaceous sandstone

at base of Jmj. Prospected from adit. Sample,

0.26 percent eU3O8. Mineralized zone at base of Jmj_ ____ ___ ______

Deposit near or at base of Jmj __ _____ _ __ __ _ _

Deposit in Jmj. (Probably located by drill holes.) ____

Deposit located by drill hole in Jmj _ _____ ____

do _ _ ___ __ _ __ _____ ______ __ ______

Autunite occurs along joints and fractures, principally near base of trachyte sill. Sill intrudes Mesaverde Group, strikes northwestward, and dips

about 30° E. Grab sample, 0.13 percent eU3O8 .

Radioactive anomaly in Jmj _____ . __ __________

Autunite and other unidentified uranium minerals,

associated with abundant selenium, ' occur in

carbonaceous zones in sandstone in upper part

of Galisteo Formation. Core sample, 2.70 percent

U3O8.

Secondary uranium minerals occur in sandstone

and shale in Mesaverde Group. Grab sample, 0.54

percent eU3O8.

Secondary uranium minerals occur sparsely with

limonite and carbonized fossil logs along bedding

of Santa Fe Group. Mineralized zone is 1-6 in.

thick and 15 ft long. Grab sample, 0.54 percent

eU3 08 .

Anomaly in sandstone in upper part of Jmb_

 do 

do

do _

__ __do____ ____ ____ __ ___ __ -_-_ _ __

do

do__ __ _ __ _ __ _____ __ ____ _ _____ __

do _ _____ __ ___ _ _ __ __ ______ __ __

 do 

_____do __ _ __ ____ __ -___ _---__-_- -_--__-_

Spotty radioactive zones along about 1,500 ft of

outcrop in sandstone that is probably in upper

part of Jmb. Radioactive material is concentrated

around mudstone galls and lenses in limonite

stained and faulted sandstone.

Same as Morris- Peters, sec. 17 (above) __ __________ _

Same as Morris- Peters, sec. 17 (above). Sample,

0.36 percent eU3 08.

Radioactive zones in bands as much as 1 ft thick

and in pods around large mudstone galls in

Dakota Sandstone. Some carnotite visible on

joint surfaces and outcrop faces. Sample, 0.04

percent U.

Deposit in Jmw. Some ore mined, 1957-64__ _ _____

Several small deposits in Jmw__ _______ ____ _____

W. L. Chenowith

(WC, 1956).

R. D. Lynn (OC,

undf +,ed) . W. L. Chenowith

(WC, 1956).

Do.

Do.

R. D. Lynn (OC,

undr.ted).

G. E. Collins (WC,

1955).

The Anaconda Co.,

DH, 1956

Dial Exploration Co.

(WC, 1960).

R. B. 8<roud (WC,

1956^ .

Do.

AEC, DH. D">.

Do. D-.

D-.

Do. D-.

Do.

Do.

Do.

J. W. Allison and

R. Y. Nestler

(WC, 1954).

Do.

Do.

P. E. Melancon

(WC, 1952).

AEC, DH.

L. R. Kittleman and

(WC, undated).
URANIUM DEPOSITS 

TABLE 4. Uranium deposits, by county, in northwestern New Mexico Continued

49

Name of deposit

Location

Sec. T. R.

Description of deposit and sample Source of data

Sandoval County Continued

Section 25 *SWtf 25.______ 17 N. 1 W.

(Collier). 

Section 36. _______ *SW# 36_______ 17 N. 1 W.

Peralta Canyon.. __ *NW#SE# 9 _ 17 N. 5 E. 

Unnamed.________ *SW}£ 13.___.__ 18 N. 1 W.

Deer Creek ______ C. 35_ _ _ ___ 18 N. IE.

Unnamed.-__--.__ *13.___________ 18 N. 2 E.

Tex-N_-__-__-.__ *C. 34___.__._. 18 N. 2 E.

Mauldian__ ______ Near junction 19 N. 1 W.

of 1 and 2. 

Clearv----------- Etf 14______ ___ 19 N. 1 W.

Yellow and green uranium minerals in 18-ft-thick

fine-grained iron-stained sandstone in Jmb. Grab 

sample, 0.61 percent eUsOg.

Torbernite and uranophane, associated with copper 

oxides, coat fracture surfaces and fill interstices of 

brecciated rhyolite.

Radioactive shale in Dakota Sandstone- .__ __ __

sandstone of Abo Formation. Lens is 150 ft long, 

22 ft thick, and extends unknown distance back 

from outcrop, but is exposed to face of 24-ft adit 

of old copper prospect. Visible yellow-green 

uranium mineral associated with chalcocite, 

bornite, chalcopyrite, malachite, and azurite. 

Channel sample, reportedly 0.08 percent eU3O8 .

that extends along strike about 200 ft in basal 

sandstone of Abo Formation. Sandstone is about 

25 ft thick, contains carbonaceous plant debris, 

and has spotty distribution of malachite and 

azurite. Exposure is in footwall of northeasttrending Jemez fault where beds dip about 45° 

SE. Channel sample, 0.02 percent U3O8 . 

Radioactive zone in shallow prospect pit immediately west of Jemez River, near base of 60-ftthick sandstone in Abo Formation. Radioactivity 

is concentrated along carbonaceous seams that 

are 3 in. to 1 ft thick, 1-3 ft apart stratigraphically, 

and in zone about 10-12 ft thick but of unknown 

lateral extent. Copper carbonate minerals show, 

but no uranium minerals visible. Grab sample, 

0.07 percent U3O8 .

Radioactive zone of carbonaceous shale 2-3 ft thick,

A. Mirsky (WC,

1953). 

AEC.

Jones (1904, p. 342); 

Lindgren, Gratcn, 

and Gordon 

(1910, p. 162).

W. L. Chenowith

and P. H. 

Knowles (WC, 

1956).

Do.

R. K. Nestler (WC,

1955). 

Unknown.

D. E. Mathewson

Butler Bros. 1 (J)~ WJiNEtf 23.... 19 N. 1 W.

North Butte. Parts of 28, 29, 

32, and 33.

19 N. 1 W.

South Butte.

Unnamed.

Parts of 2, 3, 18 N. 1 W.

and 11; and

parts of

33-35. 

NWMNWJ4 35_ _ 19 N. 1 W.

occurs about 8-12 ft above base of Dakota Sandstone and extends about 800 ft along outcrop. 

Grab sample, 0.06 percent eUsO8 . Associated 

small lens of impure coal assayed 0.088 percent U.

A carbonaceous shale, or peat, unit about 1 ft thick, 

at base of Dakota Sandstone is mineralized for 

about 100 ft along outcrop on the southeastern 

upthrown side of high-angle cross fault. Some ore 

mined in 1954 and 1957.

Uranium occurs erratically near top of La Ventana 

Mesa in two areas, principally at North Butte and 

partly at South Butte, respectively. The uranium 

is in a zone several feet thick at top of the Menefee 

Formation, immediately below base of La Ventana 

Tongue of Cliff House Sandstone. The uraniumbearing zone includes three beds: an upper bed, 

6 in.-6 ft thick, of friable gray sandstone containing fragments of carbonaceous debris; a middle 

bed, 2 in.-4 ft thick, of coal and impure coal; and a 

lower bed, as much as 10 ft thick, of carbonaceous 

shale. These three beds are somewhat lenticular 

and not always distinct. The middle bed contains 

the highest grade deposits, locally as much as 0.62 

percent uranium. Uranium minerals are not visible, 

but coffinite has been identified in coal.

Same as North Butte (above) but not as extensive...

(WC, 1953);

Bachman and

olhers (1959, p. 

299-300, 306). 

H. G. Brown III

and Larry Werte

(WC, 1954);

Gabelman (1956a,

p. 308, 312). 

Bachman and others

(1959); J. D.

Vine, G. O.

Bachman, C. B.

Read, and G. W.

Moore (WC, 1953).

Three uranium-bearing zones, each about 1 ft thick 

and consisting of carbonaceous shale, occur near 

top of Point Lookout Sandstone. Sample assayed 

0.12 percent U.

Bachman and 

others (1959, p. 

295-307).

Bachman and others 

(1959, p. 300, 306).
50 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO 

TABLE 4. Uranium deposits, by county, in northwestern New Mexico Continued

Name of deposit

Location

Sec. T. R.

Description of deposit and sample Source of data

Sandoval County Continued

Houston________-_ 3. 19 N. 2 W. Radioactive zone in lower 3 ft of Ojo Alamo Sandstone. Sandstone is conglomeratic and limonite 

stained and contains carbonized wood fragments. 

Deposit is underlain by 5-ft-thick green mudstone. 

Grab sample of limonitic sandstone, 0.05 percent

D. E. Mathewson 

(WC, 1953).

Cuba 13 ___.-_-__

Kimbeto T. P_ _.

Dodge Brothers 

(Airborne 

anomaly 1).

Dodge Brothers 

(Airborne 

anomaly 2).

Dennet Nezz (24) 

Dennet Nezz 2

(*£). 

Dennet Nezz 3

(»tf). 

Enos Johnson 3 

(South Peak) 

(33). 

Horace Ben 1 (4!)

Carl Yazzie 1 (15) _

35(?)_. _________ 19 N.

26_____-._____ 23 N.

*Approx. 5 or 6_ 23 N. 

*Approx. 16_-_- 23 N.

*Approx. 23 or 24 N. 

24.

*NEK 18- -_ 25 N.

*NE}4 18 _ 25 N.

*NW% 18____._ 25 N.

*SWWNW 1 i 19 25 N 

*SE# 19---__-- 25 N.

*NW#NWK 30_ 25 N.

2 W.

10 W.

19 W. 

1Q W

20 W. 

20 W.

20 W.

20 W.

20 W. 

20 W.

20 W.

Radioactive zone at base of La Ventana Tongue of

Cliff House Sandstone. The deposit is in limonitestained carbonaceous sandstone. Channel sample, 

1 ft thick, 0.07 percent eU3O8 .

San Juan County

Uranium-bearing zone, 1-3 ft thick, in fine-grained

carbonaceous sandstone of Ojo Alamo Sandstone. 

Zone immediately underlies conglomeratic sandstone containing petrified logs, is about 50 ft above 

the Kirtland Shale, and extends along outcrop 

discontinuously about 2,000ft. Sample brought in 

by prospector assayed 0.12 percent U3 Og. 

Zone of carbonaceous siltstone about 5 ft thick in 

upper part of Gallup Sandstone. Estimated grade 

as much as 0.14 percent eU3Og.

2,500 ft along Dakota Sandstone hogback. Lithology not reported. Grab sample, 0.06 percent eU3O8 . Mineralized carbonaceous shale 0.5-2 ft thick in 

upper part of Gallup Sandstone is exposed in opencut along outcrop for about 100 ft. Estimate grade 

as much as 0.05 percent eU3 Og. 

Uranium minerals in fractures in calcified fossil logs

and peripheral to logs in sandstone in lower part 

of Jmr. Some ore mined from opencut, 1953-55. 

Similar to Dennet Nezz (above). Some ore mined

from opencut in 1955. 

-_ do. ___._-_- ._- --._--_---- __

Small and medium deposits in sandstone in upper 

part of Jmr. Ore mined from adits, 1952-64.

Small deposit in sandstone in upper part of Jmr.

Some ore mined from opencut in 1952. 

Small deposits in sandstone in Jms. Some ore mined

H. G. Brown III

(WC, 1954).

W. L. Chenowith

(WC, 1955).

B. J. Archer, Jr.

(WC, 1955).

P. E. Melancon (WC,

19£2).

B. J. Archer, Jr. 

(WC, 1955).

J. W. Blagbrough and

others (WC, 1959) ; 

AEC. 

Do.

Do.

J. W. Blagbrough and 

others. (WC, 

19f 9) ; AEC. 

Do.

J. W. Blagbrough and

Tyler____ 

David Kee.

11 

*CSH 11

_ 25 N. 

- 25 N.

Kee Tohe (48) . 

John Joe 1 (46) _

Castle T'sosie (17). 

Joe Ben 1 (44)

Joe Ben 2__. 

Alfred Talk.

ll-_ 25 N. 

11___ 25 N.

l___ 25 N. 

13__ 25 N.

13-_____ 25 N. 

£ 14__ 25 N.

21 W. 

21 W.

21 W. 

21 W.

21 W. 

21 W.

21 W. 

21 W.

Joe Ben 3 (46) _ _ _ _ *NE^NE^ 24. _ 25 N. 21 W.

from opencut in 1954. U:V ratio 1:3. No deposits 

have been reported in Jms south of this locality.

Tyuyamunite coats fracture surfaces in folded 

coarsely crystalline Todilto Limestone. Deposit is 

about 15 ft wide and 1 ft thick.

Small deposits in calcified fossil logs and peripheral 

to logs in sandstone in lower part of Jmr.

Several small deposits in sandstone in upper part of 

Jmr. Some ore mined from opencut in 1954.

Small deposits in sandstone in Jms. No deposits in 

Jms reported north of this locality in Chuska district. Some ore mined in 1955 from opencut. U:V 

ratio 1:2.

Small deposit in sandstone in upper part of Jmr. 

Some ore mined from opencut in 1956.

Small deposits in sandstone, generally around carbonized wood, in Jms. Some ore mined from opencut in 1952. U:V ratio 2:1.

Similar to Joe Ben 1 (above)_________-L--______-

Small deposit in sandstone in Jms. Channel sample 

1 ft thick, 0.22 percent U3O8.

Small deposits in sandstone in Jms. Some ore mined 

from opencut, 1953-55; U:V ratio 1:2.5.

D. A. Thieme (WC, 

19f4); J. W. Blagbrcugh (WC, 

1956); AEC. 

J. W. Blagbrough 

(WC, 1954).

J. W. Blagbrough and 

D. A. Thieme 

(WC, 1954). 

Do.

J. W. Blagbrough and 

D. A. Thiem e (WC, 

1954); AECDo. 

Do.

Do. 

Do.

Do.
URANIUM DEPOSITS 

TABLE 4. Uranium deposits, by county, in northwestern New Mexico Continued

51

Name of deposit

Location

Sec. T. R.

Description of deposit and sample Source of data

San Juan County Continued

Enos Johnson (80}. *SE% 24(?).___. 25 N. 21 W.

Enos Johnson 1 

(SI).

Enos Johnson 2

(#8). 

Reed Henderson

*SE^24(?).

*SEJi24(?).

25 N. 21 W.

25 N. 

25 N.

21 W. 

21 W.

H. B. Roy 2 (40) *C. 14-23______ 26 N. 21 W.

Small to medium deposits in sandstone in Jms. Ore 

mined in 1952-54.

Small deposits occur in sandstone in Jms. Some ore 

mined, 1952-55.

Similar to Enos Johnson 1 (above). Some ore mined, 

1952-54.

Tyuyamunite and metatyuyamunite occur sparsely 

on joint surfaces and as vug linings in recrystallized 

calcite in upper 5 ft of Todilto Limestone along 

outcrop from Reed Henderson claim to head of 

north branch of Sanostee Wash, a distance of about 

4 miles. Deposits are principally on flanks of intraformational anticlinal folds, which have amplitudes 

of as much as 1-2 ft, are about 3 ft wide, and 10- 

15 ft long. Limestone is mineralized in areas of 

most intense folding, where axes of folds are 

subparallel. Cuprosklodowskite reported in area 

(Gruner and Smith, 1955). About 24 tons of subore-grade material shipped from Reed Henderson 

in 1954.

Small deposits in sandstone in upper part of-Jmr. 

Some ore mined from opencut in 1954.

P. C. Ellsworth (WC, 

undated), J. W. 

Blagbrough and 

D. A. Thieme (WC, 

1954), and J. W. 

Blagbrough and 

others (WC, 1959); 

AEC.

J. W. Blagbrough r.nd 

others (WC, 1959); 

AEC. 

Do.

J. W. Blagbrough, 

D. A. Thieme, B J. 

Archer, Jr., and 

R. W. Lott (WC, 

1959); AEC.

J. W. Blagbrough 

and D. A. Thieme 

(WC, 1954).

Canyon 2_

Unnamed.. __ __

Do. _______

Do ____--__

Do___________

Salt Canyon (73) _

Lookout Point (55) _ 

Unknown _

Nelson Point (60) _ - 

Shadyside (03)____

Shadyside 2 (94) 

Tent (99) - 

*35__-_._______

*NE#SWK2___

*SK 2 and

Ntf 11. 

*NWK 11------ *SWKH ----

*S^ 11 and

NJ_ 14. 

 NEK 14-_____

 StfSEtf 14__..__ 

*SWK 14 and

NWK 23.

*SEKNW^23__

*Near CN^ 

N^23.

*Near CNtf 

N}£ 23.

*E^NEX 23____

27 N.

29 N.

29 N.

29 N.

29 N.

29 N.

29 N.

29 N. 

29 N.

29 N. 

29 N.

29 N. 

29 N.

21 W.

21 W.

21 W.

21 W.

21 W.

21 W.

21 W.

21 W. 

21 W.

21 W. 

21 W.

21 W. 

21 W.

Two mineralized zones, each less than 1 ft thick and

about 2 ft apart stratigraphically, in Jms, Deposits 

are in sandstone beneath 3-ft-thick mudstone and 

about 5 ft above Bluff Sandstone. Mineralized 

zone extends along the outcrop for about 1,500 ft. 

Small tabular deposit in Jms in two flat-lying layers

about 15 ft apart stratigraphically; each layer a 

few inches or more thick and exposed along outcrop about 200 ft.

-___-do-__--_-- ----------- ----------------------

_____do____________ __ _- - 

__.__do__._____---__ -- - 

Small deposit or deposits in Jms. Ore mined in 1952-

56. U:V ratio 1:9. 

Several deposits in Jms. Ore mined in 1952-56. 

U:V ratio 1:6. 

Several small deposits in Jms. Some ore probably

produced and listed under East Side mines. 

Several small and medium deposits in Jms probably 

about 75 ft above Bluff Sandstone. Deposits denned partly by drill holes and worked in several 

opencuts. Ore mined in 1952-64. U:V ratio 1:11. 

Several generally small deposits in sandstone in Jms 

about 75 ft above Bluff Sandstone. Sandstone bed 

ranges from about 1 to 20 ft in thickness and is 

elongate southeastward. Deposits also generally 

are elongate southeastward. Ore has been mined 

from several adits in 1952-56 and in 1964. U:V 

ratio 1 : 8. 

Same as for Shadyside (above); workings of two 

mines are probably contiguous. Ore mined in 

1952-55 period. U:V ratio 1:8. 

Several small deposits in Jms and similar to Shadyside (above). Deposits probably worked from 

opencut, 1955-57. U:V ratio 1:7.

K. Hatfield and J.

Craig (WC, 1953) 

K. T. Hatfield

(WC, 1951). 

AEC, DH.

Do.

Do.

Do.

AEC.

Stokes (1951) ; AEC. 

Stokes (1951).

J. A. Masters and 

others (WC, 1955) 

AEC, DH.

J. A. Masters and 

others (WC, 1955) 

AEC.

J. A. Masters and 

others (WC, 1955) 

AEC, DH. 

Do.
52 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO 

TABLE 4. Uranium deposits, by county, in northwestern New Mexico Continued

Location

Sec. T. R.

Description of deposit and sample Source of data

San Jnan County Continued

King Tutt (61)....

Begay 1 and 2(7).. 

Junction (47) ....

King Tutt 1 (5g)...

Horse Mesa _

BB (Lewis 

Barton) (4). 

BBB (Barton and 

Begay) (5). 

Canyon View (14) 

Carrizo 1 (16) . _ _

Cottonwood Butte 

(*3). 

King Tutt Point 

(53). 

Plot 7 (lower 

Oak Springs) 

(66). 

Rattlesnake 6 

(67). 

Red Rocks (68)..,

Red Wash Point 

(69). 

Rocky mine 2 (72).

Sam Point (74).. __ 

Jack Boyd

*E#SEtf23____

*E}£ 23 and 

W^NW>£ 24.

*NEtf24_______

*W}£SW>£24___ 

*SWtf 25__.____

*CW/2 26_-___-

*Uncertain _ _

* Uncertain _

* Uncertain _ __

* Uncertain

* Uncertain

* Uncertain _

* Uncertain

* Uncertain

* Uncertain

NH3__________

29 N.

29 N.

29 N. 

29 N.

29 N. 

29 N.

29-30 

N. 

29-30 

N. 

29-30 

N. 

29-30 

N. 

20-30 

N. 

29-30 

N. 

29(?) 

N.

29-30 

N. 

29-30 

N. 

29-30 

N. 

29-30 

N. 

29-30 

N. 

30 N.

21 W.

21 W.

21 W. 

21 W.

21 W. 

21 W. 

21 W. 

21 W. 

21 W. 

21 W. 

21 W. 

21 W. 

21 W.

21 W. 

21 W. 

21 W. 

21 W. 

21 W. 

15 W.

Small deposit near south margin of 50-ft-thick sandstone in lower part of Jms and probably stratigraphically below sandstone that contains Shadyside (above). Sandstone lens is elongate eastward 

and contains all deposits in general vicinity, most 

of which are also elongate eastward. King Tutt 

probably worked from opencut; some ore shipped 

in 1956. U:V ratio 1:5. 

Numerous small and some medium deposits in Jms. 

Probably similar to Shadyside (above). Deposits 

denned by drill holes. Ore mined from short adits, 

1953-64. U:V ratio 1:6. 

Small deposit in Jms. Some ore mined in 1953. U:V 

ratio 1 : 3. 

One or more small deposits in same 50-ft-thick sandstone in Jms as King Tutt (above). Deposits are 

generally elongate eastward. Ore mined in 1952-58 

period. U:V ratio 1:5. 

One or more small deposits in Jms. Some ore mined 

in 1956. U: V ratio about 1:1. 

Several small tabular deposits crop out along rim of 

. Horse Mesa in- Jms. Some ore has been mined. 

Small deposits in Jms. Ore shipped in 1951. U:V 

ratio 1:9. 

Small deposits in Jms. Ore shipped in 1950. U:V 

ratio 1 : 14. 

Small deposits in Jms. Ore shipped in 1952. U:V 

ratio 1 :6. 

Small deposits in Jms. Ore shipped in 1956-58. U:V 

ratio 1:4. 

Small deposits in Jms. Ore shipped in 1950-51 and 

1954. U:V ratio 1:8. 

Small deposits in Jms. Ore shipped in 1952-53. U:V 

ratio 1 : 5. 

Small deposits in Jms. Ore shipped in 1959-64. U:V 

ratio 1:5.

Small deposit in Jms. Ore shipped in 1956. U:V 

ratio 1 : 2. 

Small deposit in Jms. Ore shipped in 1962. U:V 

ratio 1 : 6. 

Small deposits in Jms. Ore shipped in 1952. U:V 

ratio 1:5. 

Small deposits in Jms. Ore shipped in 1952. U:V 

ratio 1:8. 

___-_do__--____-____-__- ------------------------

Uraniferous deposit at base of 30 ft-thick limonitestained tuffaceous and crossbedded sandstone near 

base of Fruitland Formation. It overlies a 10-ftthick carbonaceous claystone. Some tonnage of

J. A. Masters and 

other? (WC, 1955); 

AEC, DH.

DC.

AEC.

J. A. Masters and 

others (WC, 1955); 

AEC.

AEC. 

Stokes (1951). 

AEC. 

DC. 

DC. 

DC. 

DC. 

DC, 

DC.

DC. 

DC 

DC. 

Do. 

Do.

W. L. Chenowith 

and Ward 

Carithers (WC, 

1955).

Hogback claims__ 15 and 22______ 30 N. 16 W.

King 6 (Troy 

Rose) (50).

Rocky Flats (70) . 

Barton !_____.._. 

Hoskey Barton. _.

Rocky Flats 2 

(71).

*Near SW. cor. 

11.

*E#SWtf 14-.

*NEtf 23 ...

*Near C. 24___ 

26 ___.

30 N. 21 W.

30 N. 21 W.

30 N. 21 W.

30 N. 21 W.

30 N. 21 W.

ore-grade material reportedly shipped in 1954-55. 

Deposit thickens in depressions in underlying 

claystone. Channel sample, 0.22 percent U3Os.

Spotty scattered small limonite-stained carbonaceous 

thin uraniferous zones in sandstone near base of 

Menefee Formation. Channel sample, 0.01 percent 

U3O8, but higher grade material reportedly in drill 

holes.

Small deposit in Jms. Other small deposits in vicinity along outcrop. Some ore mined in 1956. U:V 

ratio 1:5.

Small deposit at outcrop in Jms. Some ore mined, 

1953-55. U:V ratio 1:10.

Small tabular deposit, a few inches to about 2}£ ft 

thick, in Jms. Two other small deposits nearby.

Small deposit at outcrop in Jms. Other small deposits 

in vicinity along outcrop.

Small deposit at outcrop in Jms. Many other small 

deposits in vicinity along outcrop. Some ore mined 

in 1955. U:V ratio 1:11.

DC.

AEC.

Ronald Lebrecque,

(WC, 1955); AEC. 

AEC.

K. G. Fadfield (WC,

1954). 

AEC.
URANIUM DEPOSITS 

TABLE 4. Uranium deposits, by county, in northwestern New Mexico Continued

53

Name of deposit

Location

T. R.

Description of deposit and sample Source of data

San Juan County Continued

Unknown_________ *S#NW# 35____ 30 N.

Lone Star (5^)____ *E#SW# 35____ 30 N. 

King 2 US) _______ *NW#NW# 26_ SON.

Airborne anomaly *SE}4 19- _ 31 N.

13. 

Chilton prospect___ NW#NW# 28__ 32 N.

21 W. Small tabular deposit, about 1 ft thick, in Jms. J. A. Masters and 

Deposit is about 50 ft above top of Bluff Sandstone others (WC, 1955) ; 

and near northern edge of sandstone unit that AEC. 

contains the Canyon 2 (above). Several other small 

deposits are in general vicinity in same stratigraphic zone. Ore mined in 1952 and 1962. U:V 

ratio 1 : 6.

54 period. U:V ratio 1: 12.

stone near base of Menefee Formation. Zone is (WC, 1955). 

about 1 ft thick and 30 ft in diameter and is overlain by thin coal seam. Grab sample, 0.03 percent 

eU3 O8 . 

10W. Radioactive zone in thin-bedded yellow-brown carbo- R. L. Rock (WC, 

naceous sandstone of San Jose Formation. Channel 1954) . 

sample, 0.02 percent eU3 Os.

Santa Fe County

Hiser-Moore 1___ *Approx. W/z 8__ 15 N. 7 E.

La Bajada (1). *Approx. 

 

15 N. '9. 7 E.

Airborne anomaly 

1.

Rogers No. (?)___. 

Airborne anomaly

Airborne anomaly 

9.

Rogers (?). 

Do.__

19_ ________ 15 N.

i 17____ 20 N.

17________ 19 N.

7 E. 

9 E. 

9 E.

17________ 19 N. 9E.

17____ 20 N. 9 E.

300 ft SW. and 20 N. 9 E. 

600 ft NE., 

respectively, 

of % cor. 17 

and 20.

Autunite(?) locally impregnates limonite-stained 

joint surfaces near top of flow of Cienegilla Limburgite of Stearns (1953) which strikes northeast 

and dips about 20° NW% Selected chip sample, 

0.15 percent U3Og.

Deposit occurs in Espinaso Volcanics of Stearns 

(1943) along brecciated footwall of limburgite 

dike where Espinaso is probably mostly agglomerate. Host rock is altered and impregnated 

with massive iron sulfides, sulfides of copper and 

some zinc, and possibly sulfides of nickel and 

molybdenum. Uranium, associated with some 

carbonaceous material, is localized in podlike 

zones with the base-metal sulfides. Mineralogy of 

the uranium is not known. Deposit was worked 

through a vertical shaft for copper in the early 

twenties. In 1963-64, it was being mined below 

level of streambed in open pit that exposed complex network of thin sulfide veins in the limburgite 

dike.

Radioactive limonite and silica in fracture zone in 

Santa Fe Group. Host rocks probably sandstone. 

Grab sample, 0.15 percent eU3O8 .

Deposit in Santa Fe Group, similar to Airborne 

anomaly 1 (above).

Carnotite, schroeckingerite, and meta-autunite coat 

fracture and bedding surfaces of gray claystone 

and siltstone of Santa Fe Group. Mineralized 

zone is few feet thick and extends few tens of 

feet along strike of bedding. Sample, 0.04 percent 

U3O8 .

Carnotite, schroekingerite, and meta-autunite occur 

in limonite-stained gray siltstone and sandstone 

of Santa Fe Group. Associated with abundant 

carbonized plant remains. Sample, 0.06 percent 

U3O8 .

Deposit in Santa Fe Group, similar to Airborne 

anomaly 1 (above).

Deposits in sandstone of Santa Fe Group, similar to 

those described above. Grab sample 239580, 0.03 

percent U3O8 .

FN, October 1955; 

R. M. Perhac

(WC, 1954).

J. W. Hasler (WC, 

1957); FN, 

October 1955, and 

May 1963.

N. S. Mallory and 

G. E. Collins 

(WC, 1954).

G. E. Collins (WC, 

1954) ;FN, 

October 1955.

Collins and Freeland (1956, p. 

11); R. S. Cannon, Jr., R. L. 

Smith, and H. L. 

Cannon (WC, 

1955).

Collins and Freeland (1956, p. 

11-12);

R. S. Cannon, J~., 

R. L. Smith, and 

H. L. Cannon 

(WC, 1955).

G. E. Collins (WC, 

1954); FN, 

October 1955.

FN, October 1955. 

Analysis by C. 

Angelo, J. Wahlberg, J. Schuch, 

G. Burrow, and 

J. Wilson.
54 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO 

TABLE 4. Uranium deposits, by county, in northwestern New Mexico Continued

Name of deposit

Location

T. R.

Description of deposit and sample Source of data

Santa Fe County Continued

Rogers (?). 20 and 20 N. 9 E. 

near C. 20.

9___ 20 N. 9 E.

Anomaly 1. NEtfNEtfSWtf 20 N. 9 E. 

32.

Deposits in sandstone of Santa Fe Group; similar 

to those described above.

Carnotite, schroeckingerite, and meta-autunite coat 

fracture and bedding surfaces of sandstone, siltstone, and claystone in face of shallow pit in 

Santa Fe Group. Uranium minerals are concentrated where sandstone contains clay galls 

and pockets of carbonized plant remains. Other 

deposits in vicinity are numerous but small. 

Selected grab sample 239586, 0.27 percent U3O8 .

Radioactive limonite in gray sandstone of Santa Fe 

Group. Sandstone contains clay galls and carbonaceous "trash" where radioactive. Sample, 

0.02 percent U3 O8 .

G. E. Collins (WC, 

1954); FN, 

Octol -?r 1955.

G. E. Collins (WC, 

1954); FN, 

October 1955. 

Analysis by C. 

AngeJo, J. Wahlberg, J. Schuch, 

G. Burrow, 

J. Wilson.

Collins and Freeland (1956, p. 

9-10).

Socorro County

R. D. Lynn (OC, 

undated).

"Silver Creek" *SE}£SW}£ 15. __ 1 N. 2 W. Yellow uranium minerals, associated with copper 

prospect. oxides, coat walls of old copper prospect shaft,

which is probably in Popotosa Formation. Grab 

sample, 0.30 percent UsOs. 

King claim______ 4_ _____________ IN. 4W. Radioactive limonite-stained sample of sandstone G. E, Collins (WC,

float, probably from base of Baca Formation. Grab 1954). 

sample, 0.02 percent eU. 

Hook Ranch 7_ _____________ IN. 5W. Radioactive zone in limonite-stained sandstone in Unknovni.

(Airborne in Mancos(?) Shale. Grab sample, 0.02 percent U. 

anomaly 5). 

Hot Shot. ________ W}£NWK 18__._ IN. 5 W. Radioactive anomalies in limonite-stained carbona- G. E. Collins (WC,

ceous sandstone near base of Baca Formation. 1954); Griggs and 

Sample, 0.31 percent U. Baltz (1955, p.

211). 

Hook Ranch 13__ ___________ IN. 6 W. Similar to Hot Shot deposit (above). Sample, 3.27 Griggs and Baltz

(Airborne percent U. (1955 p. 211). 

anomaly 4). 

Hogsett-Hust- NW% 24 _ ______ IN. 6 W. Meta-autunite (?) and unidentified uranium minerals G. E. Collins (WC,

Henderson 1-4 occur in limonite-stained carbonaceous, "as- 1954). 

(Airborne phaltic" sandstone of Baca Formation. Several 

anomalies 2, 3). deposits are exposed in shallow prospect pits

within area of four claims. Selected sample, 1.5 

percent U3Os. 

Hook Ranch 24_____________ IN. 6 W. Possibly one or more of Hogsett-Hust-Henderson AEC.

(Jaralosa) (2). deposits (above), or the Hust-McDonald-Brown

deposit (below). Some ore shipped, 1959-61. 

Hust-Me Donald- NE% 24________ IN. 6 W. Radioactive limonite-stained pod of conglomeratic G. E. Collins (WC,

Brown. sandstone, interbedded with volcanic rocks, prob- 1954); Griggs and

ably in upper part of Baca Formation. Sample, Baltz (1955, p. 

0.19 percent U. 211). 

Unnamed. ________ 35. ____________ IN. 6 W. A radioactive 1-ft-thick zone in carbonaceous sand- G. O. lachman,

stone in Baca Formation. Grab sample, 0.036 E. H. Baltz, and 

percent U. R. L. Griggs

(WC. 1957). 

Campbell. ________ *WJ. 22_ _______ IN. 2 E. Radioactive zone in bleached sandstone of Dockum G. E. Collins (WC,

Formation. Zone is about 20 ft thick and several 1955). 

hundred feet long. Secondary uranium minerals 

show locally. Grab sample, 0.097 percent eUsOg. 

Rayborn prospect-. NJ4 6_ _________ 2 N. 8 W. Tyuyamunite occurs in limonite-stained carbona- AEC.

ceous sandstone of Gallup Sandstone.
URANIUM DEPOSITS 

TABLE 4. Uranium deposits, by county, in northwestern New Mexico Continued

55

Name of deposit

Location

Sec. T. R.

Description of deposit and sample Source of data

Socorro County Continued

Charley 2(1). .. SWtfNEtf 35__. 3 N. 2 W.

"Shaft" prospect.- SE>i 10_ _______ IS. 2 W.

Agua Torres (.) ___ *SEtf !________ IS. 2 E.

Marie *12 and 13__--_ IS. 2 E.

Carter-TolliverCook.

Do _ _______

Lucky Don

(Bonanza 1) (1) .

EJ_ 5. 2 S. 1 W.

6___ 

NEji 35.

28. 

28.

1 W. 

2E.

Little Davie

Uranium prospect 

17.

SWJ4NEJ{35.__ 28. 

SEjiNEji 3-

2 E.

2 N. 5 E.

Carnotite, tyuyamunite, autunite, and some pitchblende are disseminated in pockets and along 

fractures and bedding surfaces in tabular zone, 

about 1-10 ft thick, of sheared dark-gray clayey 

material and bleached tuffaceous sandstone at 

base of Popotosa Formation where it is separated 

from underlying Precambrian by Cerro Colorado 

fault. Mineralized zone underlies sheared red clay 

zone about 5 ft thick and rests on brecciated 

altered granitic rock. Beds of Popotosa Formation, 

sheared zone, and underlying granite surface dip 

about 25° E. and probably mark position where 

fault flattens and swings abruptly from north to 

northwestward strike. Deposit mined from open 

pit and incline shaft, 1954-58.

Torbernite(?) and carnotite(?), associated with 

secondary copper minerals, calcite, and quartz, 

occur in shear zone in trachyandesite of Datil 

Formation. Mineralized material noted in dump 

at site of flooded vertical shaft. Sample assayed 

0.026 percent U.

Deposit in arkosic limestone member of Madera 

Limestone immediately west of steeply dipping 

north-trending normal fault that at the surface 

separates the Madera from Abo Formation. 

Deposit consists of fracture fillings by a yellow 

uranium mineral in irregular zones of siliceous 

limestone breccia. Breccia zones are in footwall 

of fault, are hematite stained, and locally as much 

as 100 ft in diameter but of unknown depth. Some 

ore was mined from shallow pits, 1955-56.

Small deposit or series of deposits in geologic setting 

similar to Agua Torres (above). The rocks are not 

as brecciated, however, and deposit consists of 

fillings of solution cavities in limonite-stained limestone by yellow uranium mineral. Some ore mined 

from open pit in 1956.

Carnotite and uranophane, associated with galena, 

pyrite, and chalcopyrite, occur in mafic dikes that 

crosscut diorite intrusive bodies. Igneous rocks 

probably intrude Santa Fe Group. Grab(?) sample, 

0.25 percent U3O8 .

Same as E}£ sec. 5 (above)____________----_-____

Deposit in middle limestone member of San Andres 

Limestone immediately east of and in footwall of 

northeastward-trending normal fault that separates the San Andres from Yeso Formation. At 

deposit the San Andres is dark-gray cherty thinto medium-bedded limestone with some interbedded white limy sandstone. Beds strike about 

N. 45° E., dip about* 25° E., and are locally crushed 

and sheared. Deposit consists of tyuyamunite and 

possibly Carnotite disseminated along fracture and 

bedding surfaces and as intergranular fillings in 

zone that is roughly tabular, is about 300-400 ft 

long, 50 ft wide, and 35 ft thick. Ore has been 

mined from short adits and an open cut in 1955-56 

and in 1960-63.

Small deposit about 1,200 ft south of Lucky Don and 

in similar geologic setting (see above). Some ore 

mined in 1955.

An unknown uranium mineral concentrated along 

fracture surfaces in red arkose and disseminated 

in carbonaceous shale in Abo Formation, closely 

associated with carbonized wood and with malachite, azurite, and chalcocite. This is old copper 

prospect and consists of two shallow shafts, a 40-ft 

incline, and several shallow pits. Chip sample, 0.11 

percent U3O8 .

FN, May 1956; 

G. E. Collins 

(WC, 1954); 

W. A. Carlson 

(WC, 1954); P. H. 

Knowles (WC, 

1957); Denny 

(1940, fig. 1); 

Kelley and Wood 

(1946).

Gott and Erickscn 

(1952, p. 4, 13).

AEC.

Do.

Unknown.

Do.

FN, May 1956; 

David Carter 

(OC, May 

1956); AEC.

Do.

Russell Gibson 

(1952, p. 22-24).
56 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO 

TABLE 4. Uranium deposits, by county, in northwestern New Mexico Continued

Location

Sec. T.

Rattlesnake... __ NWJiSEJi 15___ 3 N. 

Abo.. ____________ SE'*22________ 3 N.

Pioneer____. ._..._ 23(?)_. _________ 3 N.

R.

Socorro, County Continued

5 E. Radioactive zone in red and gray sandstone and 

conglomerate of Abo Formation. Yellow-green 

uranium mineral also occurs in surficial float. 

5 E. A yellow-green uranium mineral occurs in seam

about 2 in. thick along wall of short adit for distance of about 5 ft. Seam is in siliceous conglomerate lens in Abo Formation. Sample of seam, 13.0 

percent U3O 8 .

walls of 20-ft adit in several podlike zones and 

associated with carbonaceous layers in conglomeratic sandstone in lower part of Abo Formation. 

Podlike zones are generally an inch or less thick 

and traceable for few feet along bedding. Selected 

sample, 2.15 percent U3O8 . This deposit may be in 

sec. 22 in same general zone as Abo deposit (above) .

Valencia County

G. E. Collins 

(WC, 1954).

H. D. Volfe and

G. E. Collins 

(WC, 1954).

J. P. Hadfield, Jr.,

and H. E. Geslin 

(WC, 1953).

Br ownlow-H eath _

Crackpot (7) ______

Do___________

Do___________

Do ______..

Do _____ __

Paisano (23) ______

N#NJ_NJ_ 4____ 6 N. 

1 and 12 ___ __ 7 N.

NWJiNWtf 8 _ 8 N.

SWtfSWtfNWtf 8 N.

5.

CW#NW# 5 8 N.

SWtfSWtf 10--- 8 N.

CW# !!_______ 8N.

SE^NW>i 16___ 8 N.

4 W. 

5 W.

5 W.

6 W.

6 W.

6 W.

6 W.

6 W.

6 W.

Radioactive zone in conglomeratic sandstone about 

100 ft above base of Chinle Formation, possibly in 

Shinarump Member.

faces in impure nodular limestone and dark-gray 

shale of San Andres Limestone which is intruded 

with numerous igneous dikes and sills and is 

mineralized by copper, lead, and possibly silver 

and nickel minerals. 

Medium deposit in elongate domelike fold in Todilto

Limestone. The fold, which has closure of about 

3-5 ft on underlying Entrada Sandstone contact, 

trends northwestward and is constituted in part 

by several minor folds that radiate from central 

part of dome. Deposit was concentrated in lower 

part of limestone, where it was about 15 ft thick 

near center of dome and from where it tapered and 

thinned irregularly toward margins near periphery 

of dome. Mineralogy is similar to other deposits in 

Todilto Limestone. (See text.) Other small deposits 

occur in vicinity. Ore mined from open pit in 1955.

stone.

_____do._____.____._____ -_ __ __-- -.-

_____do______..__________.___ ___- 

_____do_.____________-_ -

Small deposit at outcrop of Todilto Limestone. Ore

AEC. 

W. A. Carbon (WC,

1954). 

FN, April 1955; J.

M. Elias (OC, 

April 1955) ; AEC.

R. H. Moench (WC,

1960). 

Do.

Do.

DC.

DC.

AEC.

Balo 18_ 8N. 6 W.

Sandy (70)________ SEtf 22________ 9 N. 5 W.

Unnamed__.___.__ CSJ4NH 27 ___ 9 N. 5 W.

mined from open pit in 1957.

Spotty occurrences of tyuyamunite and uraninite 

occur along bedding at outcrop of Todilto Limestone for distance of about 1 mile. Sample, 0.16 

percent ell.

The Sandy is a cluster of several small deposits within 

upper 15 ft of Entrada Sandstone and, locally, in 

base of overlying Todilto Limestone. Cluster is 

more or less continuous body, roughly parallel to 

the bedding, elongate eastward, roughly 5-10 ft 

thick, 10-25 ft wide, and about 600 ft long. A diabase sill, about 25 ft thick, intrudes and displaces 

the upper part of deposit. The uranium is largely 

in finely disseminated cofflnite and uraninite. Deposit was mined in 1955.

Several, generally small, deposits associated with intraformational folds in Todilto Limestone. Folds 

are sinuous, have amplitudes as great as 15 ft, and 

are displaced in places by diabasic dikes and sills, 

which are younger than primary uranium minerals.

J. W. Allison (WC, 

1954).

FN, 1955; The 

Anaconda Co., 

1955; Hilpert and 

Moerch (1960, p. 

457-459); Moench 

(1962, p. B 67- 

B69).

FN, April 1954; 

Hilpert and 

Moench (1960, p. 

459 end fig. 17).
URANIUM DEPOSITS 

TABLE 4. Uranium deposits, by county, in northwestern New Mexico Continued

57

Name of deposit

Location

Sec. T. R.

Description of deposit and sample Source of data

Valencia County Continued

Unnamed.________ CW^27_______ 9 N. 5 W.

Paraje____________ NWJi 17_______ 9 N. 6 W.

Section 4 prospect.. CEJ_ 4_______ 10 N. 3 W.

Chaves (*£)_______ 8E#22__ ___ ION. 3 W.

Several, generally small, deposits associated with intraformational folds in Todilto Limestone. Geology 

similar to other deposits in sec. 27 (above).

Conglomeratic sandstone at top of Jmb is mineralized 

just beneath northern flank of channel scour, exposed along mesa rim by bulldozer cut. Scour is at 

base of Dakota Sandstone. About 1,500 ft down 

slope a fragment of this deposit is exposed in landslide block.

Deposit exposed in short adit in sandstone in Jmr_

Deposit in medium- to coarse-grained sandstone with 

pockets of carbonized plant debris in Jmr in area 

marked by landslides and several faults. Ore was 

mined from shallow opencut and adit in 1955.

Unnamed_____ __

Do___________

Do_. _________

Townsite _ ___

Paguate (68) _ _

Oak Creek Canyon_ 

Unnamed _

Horace and 

Quemazon.

SEtfNEtf 27____

NWtf 34_ ______

CE>_3_-_______

NWJ4 4, EJ. 5,

and SEtf 33.

NE>, 10 and 

NWJi 11.

NWJi 14_______

NWtfNW^SEtf 

4.

10 N.

ION.

ION.

10 N.

10-11

N. 

ION.

ION.

10 N.

3 W.

3 W.

3 W.

5 W.

5 W.

5 W. 

5 W.

9 W.

Two small deposits in Jmw at outcrop __ _ _ _ _

Very large, elongate deposit that trends northeastward, in Jmj.

Roughly tabular deposit in Jmj. Exposed in face of 

of bulldozer cut on north slope of Oak Creek 

Canyon.

Yellow uranium minerals occur along fracture and 

bedding surfaces in lower part of Todilto LimeWilcox Ranch. _ . NE}£ 14____. _ 10 N. 15 W.

Unnamed. 

M-6 (50)_

18.______ UN. 4 W.

stone. Mineralized zone at outcrop is several tens

of feet long, a few feet wide, and several feet thick.

Sample, 0.11 percent U. 

Deposit possibly in Shinarump Member of Chinle

Formation. Located by drill hole. Sample assayed

0.14 percent UsOg. 

Two or more small deposits near top of Jmj__ ______

>i 19 and 11 N. 4 W. 

NWtf 30.

Large, tabular deposit near top of Jmj. Ore mined 

through vertical shaft, 1957-58.

St. Anthony 

(Bibo).

29_ UN. 4 W. One or more tabular deposits at top of Jmj.

Hanosh (M-l, N}£ 30_________ UN. 4 W.

M-2, and M-3). 

Unnamed__ _______ N^SEW 31_____ UN. 4 W.

Cluster of small and medium tabular deposits 0-100

ft below top of Jmj. 

Tabular deposit near top of Jmj_ __________________

L-Bar____ ________ *SW% 13 and UN. 5 W.

NWJ4 24.

Two medium to large tabular deposits in Jmj.

Unnamed.

Do. 

Do.

23 and 11 N. 5 W. 

424.

Small and medium deposits near top of Jmj.

8J_8V_24_______ 11 N. 5 W.

SE*424________ 11 N. 5 W.

Several small and medium deposits near top of Jmj _. 

Small and medium deposits near top of Jmj_-______-

Do__________ NE#25 _____ UN. 5 W.

Windwhip (_0_)___ SW^NW^ 35_._ -11 N. 5 W.

Several small deposits near top of Jmj_____________

A roughly tabular deposit about 15 ft below top of 

Jmj. Western edge exposed at outcrop, where 

mined from opencut in 1954.

FN, April 1954. 

FN, September 19 ?4.

Moench and Puffett

(1963b). 

FN, 1955.

Moench and Puffett

(1963b). 

R. H. Moench (WC,

1960). 

Do. 

The Anaconda Co.,

DH, 1957. 

The Anaconda Co.,

1957; Kittel (19"3,

p. 174). 

The Anaconda Co.,

1955; FN, 1955.

R. H. Moench (WC,

1960). 

Forrest Fincher (VC,

1954).

David Carter (OC, 

1956).

The Anaconda Co.,

undated. 

Climax Uranium

Corp., March

1957; AEC. 

Climax Uranium

Corp., March

1957. 

Do.

R. H. Moench (WC,

1960). 

The Anaconda Co.,

DH, 1957; Kittel

(1963, p. 168, 171,

174). 

Climax Uranium

Corp., March

1957. 

Do. 

R. H. Moench (WC,

1960); Climax

Uranium Corp.,

March 1957. 

R. H. Moench (WC,

1960). 

Hilpert and Moench

(1960, p. 454).
58 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO 

TABLE 4. Uranium deposits, by county, in northwestern New Mexico Continued

Name of deposit

Location

Sec. T. R.

Description of deposit and sample Source of data

Valencia County Continued

Woodrow (102).... S>_SE}4 36 and

Jackpile (43). Parts of 26 and 

35 and CN}_ 

2.

UN. 5 W. This deposit is in immediate periphery and in core

10 N. 5 W. of near-vertical pipelike structure that extends 

from surface to unknown depth. At least upper 

part is in Jmb and top 50 ft or so is in the Jmj. 

Pipe structure is roughly cylindrical, about 30 ft 

in diameter, and has known length of at least 200 

and possibly more than 300 ft. The core is breccialike and has slumped downward 30-45 ft, with 

respect to wallrock, along a ring fault. In upper 

part of structure the deposit is fairly high in grade 

and is mostly in fault zone and in favorable beds 

of the core; in lower part, deposit is mainly in 

core and is lower in grade. Mineralogy is similar 

to other deposits in the Morrison Formation in 

the vicinity, except principal ore mineral, coffinite, 

is coarse grained and the uranium and the general 

suite of associated elements, excepting vanadium, 

are roughly tenfold as abundant; the vanadium is 

about one-tenth as abundant. Deposit was mined 

in 1953-56.

UN. 5 W. Very large, roughly tabular, multilayered deposit 

in upper part of Jmj. Deposit is in thickest part

10 N. 5 W. of sandstone, is roughly elongate northward, and 

is coextensive with black carbonaceous material. 

Deposit is closely related to sedimentary structures and may also be partly controlled by broad 

pre-Dakota folds. Principal ore mineral is finely 

disseminated coffinite. Since 1952 deposit has 

yielded several million tons of ore.

UN. 9 W. Small deposit 2-3 ft thick, in Todilto Limestone. 

Some ore mined 1954-55.

UN. 9 W. Small deposit in Todilto Limestone. Ore mined from 

adit, 1954-55.

UN. 9 W. Medium, elongate deposit, associated with easttrending intraformational fold in Todilto Limestone. Deposit mined from open pit, 1952-57. 

Other small deposits in vicinity. 

Radioactive zone in basal conglomerate of Abo 

Formation immediately above contact with Precambrian granite. Zone contains copper carbonates, 

carbonaceous fossil logs, and macerated plant 

debris and is 1,500 ft long and 200 ft wide. Deposit 

has been worked for copper. Chip sample 2% ft 

thick, 0.03 percent eU3Og .

*Approx. CE}_ 12 N. 4 W. Deposit, located by drill hole, possibly in, and near, 

23. west pinchout of Jmj.

Do_______ *W}_ 30________ 12 N. 4 W. Deposit in Jmj.

Tom 13 (47) _____

Lone Pine 3 (21)... NE}£ 8_

Cedar 1 (Section NW%SE}£ 20_. 

20; Yucca) (5).

Ingerson_____.____ NW^SW^ 7..._ 11 N. 12 W.

Unnamed.

FN: Tv e Anaconda 

Co.; Hilpert and 

Moench (1960, 

p. 456-457); 

Wyr? (1963).

Do_________ *SE#30___

Do__________. *N}_ 35--__

Do.________ *E>. 36_-__

Double Jerry NWtfNWtf

(Vallejo; NW}i 3.

Farris 1) (9).

Red Bluff 3 (24) CNE}4 4___

Red Bluff 5 (25) CNEJ4 4___

Christmas Day (6). SE}iNE}i 4.

12 N. 

12 N. 

12 N. 

12 N.

12 N. 

12 N. 

12 N.

4 W.

5 W. 

5 W. 

9 W.

9 W. 

9 W. 

9 W.

.do. 

.do_ 

.do.

Small and medium deposits occur at northeast end of 

stringlike cluster in the Todilto Limestone and are 

associated with set of intraformational folds that 

generally trend southwestward through sec. 4 into 

sec. 9. Ore mined from incline shaft, 1957-62; 

entry is in SW. cor. sec. 34, T. 13 N., R. 9 W.

Small deposit in Todilto Limestone immediately 

north of Red Bluff 9. Deposit mined from open pit, 

1952-56.

Small deposit in Todilto Limestone immediately 

west of Red Bluff 3. Ore mined from open pit in 

1954.

Elongate cluster of small to medium deposits, in 

lower part of Todilto Limestone, that trends 

northeasterly, extends through area about 1,500 ft 

long, ranges from few feet to about 200 ft wide, 

and averages several feet thick. Deposits mined 

from open pit, 1954-56.

The Anaconda Co., 

1955-57; Hilpert 

and Moench 

(19PO, p. 450-454); 

Kittel (1963); 

Moench (1963c).

AEC.

Do. 

FN, 1954-55; AEC.

L. H. Baumgardner 

(WC, 1954).

R. D. Lynn (OC, 

undated); R. H. 

Moench (WC, 

196^).

R. D. Lynn (OC,

undated).

Do.

Do.

Do.

FN, 1957; Gabelman 

(1956b, p. 391- 

39^): AEC.

FN, 1954; AEC.

FN, 1955; Colamer 

Corp., DH, 1954; 

AE1
URANIUM DEPOSITS 

TABLE 4. Uranium deposits, by county, in northwestern New Mexico Continued

59

Name of deposit

Location

Sec. T. K.

Description of deposit and sample Source of data

Valencia County Continued

Red Bluff 9 (*7)___ CNE}£ 4__ _____ 12 N. 9 W.

Red Bluff 7 (26)... SE#SW# 4_____ 12 N. 9 W.

Black HawkBunney (4).

CSEJ4 4..______ 12 N. 9 W.

UDC 5 (49)....... CSE#4________ 12 N. 9 W.

Gay Eagle (13).... SWtfSEJi 4._.__ 12 N. 9 W.

Red Bluff 10 (13).. SE#SW#SEtf 4_ 12 N. 9 W.

Red Bluff 8 (13)... SW#SWtfSEtf 4_ 12 N. 9 W.

UDC !___________ SEtfSEJiSEtf 4_ 12 N. 9 W.

Last Chance (19)__ NE#NE#8____ 12 N. 9 W.

Section 9 (SO)_____ NW#9________ 12 N. 9 W.

Section 9_ ________ Near SW. cor. 12 N. 9 W.

NE# 9. 

Do___________ CW#NEtf9____ 12 N. 9 W.

Do___. _______ NW#SW#9____ 12 N. 9 W.

Taffy (98)........ SW#SW#11___ 12 N. 9 W.

_ 12 N. 9 W.

_ 12 N. 9 W.

12 N. 9 W.

Zia (5£)__________ CEHSWtf 15__

La Jara (18)..^... NW#SE# 15__

F-33 33 and 

SWtf 34.

Unnamed_______ CW#16_______ 13 N. 8 W.

Section 30 (San 30________ _ 13 N. 8 W.

Mateo) (88).

Small deposit in Todilto Limestone immediately 

west of Christmas Day (above). Small amount of 

ore mined from open pit in 1955.

Two or more small, elongate, westerly trending 

deposits in Todilto Limestone. Ore mined from 

open pit, 1953-58.

Elongate, medium, and small deposits in middle of 

Todilto Limestone. This cluster of deposits 

generally trends northwesterly from the Gay 

Eagle. Ore mined from opencut, 1952-63.

This deposit is southern extension of adjoining Black 

Hawk (above). Deposit mined from opencut, 

1953-54.

Elongate, rather discontinuous, medium deposit in 

middle of Todilto Limestone. Deposit trends 

northerly, is about 400-500 ft long, a few feet to 

several tens of feet wide, about 5-20 ft thick, and 

generally follows a rather complex northerly trending, intraformational fold. Deposit mined from 

opencut, along with Red Bluff 8 and 10, 1952-64.

Southward extension of Gay Eagle deposit. (See 

above.)

Medium deposit or cluster of small deposits in 

Todilto Limestone immediately west of, and 

similar to, Red Bluff 10 (above).

Small deposit, defined by drill holes, in middle of 

Todilto Limestone. Highest radiometric reading 

about 0.10 percent eUsO9 .

Several small and medium deposits in Todilto Limestone. Generally irregular in outline. Ore mined 

from opencuts, 1952-56.

Many small and medium deposits largely clustered 

and irregular in outline. Deposits are associated 

with intraformational folds in Todilto Limestone 

that have diverse trends and that range in size 

from folds with amplitudes of only a few inches to 

several feet and in length from a few feet to several 

hundred feet. One deposit about 1,000 ft south of 

north }i cor. is C-shaped, 300 ft in diameter, and 

open to west. Deposits mined from open pits,

1953-62.

Tabular, doughnut-shaped deposit, about 150 ft in 

diameter, exposed at rim in Todilto Limestone.

Cluster of deposits, irregular in outline, in Todilto 

Limestone.

Cluster of small deposits in Todilto Limestone. 

Generally are elongate easterly to northeasterly.

Small deposit in sandstone in Jmpc. Ore is associated 

with carbonized plant debris and clay galls. Some 

ore mined in 1961.

Deposit in lower part of Todilto Limestone and upper 

part of Entrada Sandstone.

One or more small deposits in Todilto Limestone. 

Deposit mined with Zia, 1952-60.

A cluster of deposits mostly in middle and upper part 

of Todilto Limestone. Principal deposit is stringlike, trends about N. 70° E. along intraformational 

fold, is about 100 ft wide, as much as 15 ft thick, 

and more than 1,200 ft long. Ore mined from adit,

1954-59. 

Deposit in the Jmw_____-__---_---_--------------

Several large and medium deposits in Jmpc. Deposits

are generally elongate southeastward.

FN, 1954; AEC.

Gabelman (1956h, 

pi. 10); AEC.

FN, 1954; Malco'tn 

Larson, DH, 

July 1954; AEC.

FN, July 1954; AEC.

FN, July 1954; 

Gabelman (1956b, 

p. 397-399); AEC.

FN, July 1954. 

Do.

Do.

The Anaconda Co. 

and FN, 1954-55.

The Anaconda Co., 

1955.

The Anaconda Co., 

DH, 1955. 

Do.

Do.

Eugene Berkoff 

(WC, 1961); AEC.

AEC. 

Do.

The Anaconda Co , 

1957; Hilpert and 

Moench (1960, 

p. 460-461); AEC.

AEC, DH.

Rare Metals Corp.,

October 1957;

Rapaport (1963-

fig. 1).

329-381 O «9 5
60 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

PENECONCORDANT DEPOSITS IN SANDSTONE

The uranium mineralogy of the peneconcordant deposits in sandstone varies among deposits, districts, 

and areas, and stratigraphically depending principally 

on the contents of uranium and vanadium or uranium 

and copper and the degrees of oxidation. Generally the 

minerals consist of fine-grained and earthy assemblages 

of oxides and silicates of low-valent uranium and vanadates of high-valent uranium. The low-valent minerals 

generally are primary or early and the high-valent 

minerals are secondary and later. For a general background on these relations see Weeks and Thompson 

(1954), Botinelly and Weeks (1957), and Garrels and 

Larsen (1959). Because of stratigraphic differences, 

the mineralogy and habits of the deposits are summarized under the respective formational units. Deposits in the Morrison Formation, because of their great 

importance and some areal differences, are described by 

mining districts and areas, in the order of magnitude 

of the ore shipments made through 1964. The other 

deposits are described under the respective stratigraphic 

units, from oldest to youngest.

MORRISON FORMATION

AMBROSIA LAKE DISTRICT

Deposits in sandstone in the Morrison Formation in 

the Ambrosia Lake district occur principally in the 

Westwater Canyon Member, less abundantly in the 

Brushy Basin Member, and as small scattered occurrences in the Recapture Member. About 100 deposits 

or clusters of deposits are listed, of which 44 have 

yielded ore (pi. 1). Of these, 24 are principally or 

entirely in the Westwater Canyon and the others are 

in the Brushy Basin.

The uranium-vanadium ratio among the shipments 

made from 13 properties ranged from 1:1 to 3:1 

and averaged 2:1. These ratios are determinations for 

256,500 tons of ore shipped from 1950 to 1958. Nearly 

all of this ore was partly oxidized and probably averaged somewhat higher in vanadium than did the unoxidized ores. For about 219,000 tons of ore, the CaCO3 

(lime content) ranged from 1.5 percent to 9.2 percent 

among 19 different properties and averaged about 5 

percent.

STRATIGRAPHY

The Morrison Formation in the district consists of 

the Recapture, Westwater Canyon, and Brushy Basin 

Members. It crops out from the Continental Divide, 

a few miles north of Highway 66 at the west side of 

the district, southeastward for about 30 miles and 

then swings southward and pinches out under the preDakota erosion surface a few miles southeast of Grants 

(pi. 1). North from the outcrop the Morrison generally

dips northeastward at a low angle under the San 

Juan Basin and eastward into the McCart^s syncline. 

Throughout most of the district the formation is about 

500 feet thick, but it tends to thicken northward and 

attains its greatest known thickness of abc^it 800 feet 

in the central part of the district, in the western part 

of T. 16 N., R. 7 W.

The basal member, the Recapture, cons;sts of distinctive alternate beds of reddish-brown, light-gray, 

and grayish-red sandstone and siltstone, which range 

in thickness from a foot or so to about 20 feet. The 

sandstone is mostly fine grained, soft, clayey, and 

poorly sorted. Crossbeds are mostly small scale, and 

scours, which are mostly at the base, are shallow and 

rarely have a relief of more than about 1 foot. In 

thickness, the Recapture ranges from about 50 to 300 

feet, but in most places is about 150 feet. Locally, 

thicknesses vary considerably from adjoining localities 

because of iiitertonguing and grading of the member 

with the overlying Westwater Canyon Member. Few 

data are available on- the sedimentary tro-ids of the 

Recapture in the district. Regional studies (Craig and 

others, 1955, fig. 22) indicated that the disfrict marks 

the transition between conglomeratic facies to the 

southwest and sandstone-mudstone facies to the northeast. Such data are largely academic because the member is barren of uranium- deposits of any significance 

and is not considered favorable for them.

The Westwater Canyon Member is principally a 

light-yellow-brown to gray fine- to coarse-grained 

poorly sorted crossbedded sandstone. It is arkosic and 

locally contains small lenses of granules and small 

pebbles and some seams and thin beds of mudstone 

and siltstone. Fragments of silicified logs are present 

locally, but mostly are small. Crossbeds in the sandstone are small- to medium-scale trough type and dip 

southeastward in the lower part and northeastward in 

the upper part (E. S. Santos, written comnun., 1963). 

The member ranges in thickness from a little less than 

50 feet to about 300 feet and averages about 150 feet.

The Brushy Basin Member is chiefly greenish-gray 

mudstone and claystone, but contains much interbedded 

sandstone and a few thin beds of gray limestone. The 

sandstone beds are similar in color and lithology to the 

beds of the Westwater Canyon, range in thickness from 

a foot or so to several tens of feet, and locally extend 

for several miles. The Brushy Basin conformably overlies the Westwater Canyon Member and is overlain 

unconformably by the Dakota Sandstone. The contact 

with the Westwater Canyon is gradational, and because 

the two members intertongue, the selection of the contact is arbitrary. It is defined here as the base of the 

lowermost persistent mudstone or claystone unit. Along
PENECONCORDANT DEPOSITS IN SANDSTONE 61

the outcrop north of U. S. Highway 66, the Brushy 

Basin is about 100-125 feet thick. Northeastward and 

eastward it thickens and is more than 300 feet thick 

in the central part of the district and in the central 

part of T. 13 N., R. 8 W., as far east as data are 

available.

The uranium deposits in the Brushy Basin are in 

several sandstone units, but most of them are in a tongue 

that extends eastward from the upper part of the 

West water Canyon Member and is referred to as the 

Poison Canyon sandstone of economic usage (Hilpert and Freeman, 1956). It extends from its westernmost outcrop in the El/2 sec. 14, T. 13 N., R. 10 W., 

eastward into the lower part of the Brushy Basin at 

least 8 miles to sec. 31, T. 13 N., R. 8 W. It is exposed 

along the outcrop west of the San Mateo road, perhaps 

locally east of that road, and can be traced in the subsurface for as much as 1-3 miles northward as well as 

eastward. It generally ranges in thickness from 30 to 80 

feet and is separated from the Westwater Canyon Member by a 15- to 25-foot-thick claystone unit.

The Poison Canyon sandstone is structurally and 

lithologically similar to the Westwater Canyon Member 

and is composed of a complex assemblage of crossbedded and locally flat-bedded sandstone units and 

interbedded thin and discontinuous mudstone units. It 

contains numerous mudstone galls and scattered fragments of silicified and coalified plant debris. Cutand-fill structures are abundant at the base of the 

unit as well as at the bases of the internal crossbedded 

units. The Poison Canyon was deposited by eastwardflowing currents, as indicated by the crossbeds, log 

orientations, and heavy-mineral lineations (Rapaport 

1963, p. 122).

Deposits also occur in other sandstone units, and 

generally in the lower part of the Brushy Basin. Some 

may occur in northward extensions of the Poison Canyon sandstone, but they more likely occur in unrelated 

units in the same stratigraphic position. In the western part of the district, north of Prewitt, the Francis 

and Evelyn deposits are at the top of the Brushy 

Basin in a sandstone unit that is about 50 feet thick, 

is light gray or white, and directly underlies the 

Dakota Sandstone. Northeastward, back from the outcrop, the host sandstone is light brown to reddish 

brown and is as much as 80 feet thick. Drill-hole data 

indicate it splits and tongues out into the claystone of 

the Brushy Basin within a few thousand feet northeast. East of the Bluewater fault, its extent is unknown. 

A similar sandstone unit at the top of the Brushy 

Basin crops out in sec. 34, T. 14 N., R. 12 W., as reported by Konigsmark (1955, fig. 1), but he did not 

specify its thickness and extent. Immediately north of

the Francis deposit and beyond the limits of the 1 *>st 

sandstone of the Francis-Evelyn, the Alta deposit 

occurs principally in a sandstone tongue, a few feet 

thick, that splits from the top of the Westwater Canyon Member and extends eastward a few hundred feet 

into the claystone of the Brushy Basin.

STRUCTURE

The district is on the northeast flank of the Zuni 

uplift on a homocline referred to as the Chaco slope in 

the area where the east flank of the homocline merges 

with the Acoma sag (fig. 3). Throughout most of the 

district, the beds dip northeastward about 3°-5° into 

San Juan Basin, but they are flexed and faulted downward along the east side of the Chaco slope into the 

McOartys (Mount Taylor) syncline, a large northeastward-trending fold.

Locally the beds are broken and arched along farlts, 

joints, and minor folds. Granger, Santos, Dean, and 

Moore (1961, p. 1186) arbitrarily divided the faults 

into three sets according to their strikes: (1) nortl x to 

northeast, (2) northeast to east., and (3) northwest. All 

are normal faults, with the exception of a few that are 

east trending. The largest and most continuous faults 

trend north to northeast. Some can be traced for tens 

of miles and have as much as several hundred feet of 

throw. Faults of the other two sets have a much shorter 

strike length and a smaller displacement.

Most joints in the district are subparallel to nearby 

faults, but randomly oriented joints are abundant 

in some places (Granger and other, 1961). The fact 

that the joints generally are most abundant in faulted 

areas and are least abundant in unfaulted areas indicates that they are closely related to the faults and probably are the same age.

Most prominent of the smaller folds are the Smith 

Lake (Mariana) anticline in the western part of the 

district, the Walker dome (North Ambrosia dome or 

anticline) and Ambrosia dome (South Ambrosia anticline) in the central part, and the San Mateo and 

Miguel Creek domes in the eastern part. From easf to 

west the long axes of these structures swing from 

northeast to northwest, similar to the trend of the 

axis of the strongest fault set. These fold structures 

range in width from 2 to 5 miles and in length from 

4 to 10 miles, and they have a structural relief of as 

much as 1,000 feet.

In addition to the small domal folds, several poorly 

defined northeastward-trending broad anticlinal and 

synclinal folds are in the area just north of Grants 

and Bluewater. As shown by Gabelman (1956b, fig. 

132), these folds are 2-4 miles wide and their nxes 

swing from a northeastward trend in the eastern part
62 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

of the area to a northward trend in the western part 

and are generally bounded by the principal faults of 

the north- to northeast-trending set. Such structures, 

at best, are poorly defined by the structure contours 

drawn on the base of the Dakota Sandstone, except 

for a fold shown in the area just east of the area of 

Gabelman's illustration (Thaden and Santos, 1963).

Less conspicuous but important structures because 

of their influence on the uranium deposits, are a set 

of rather shallow eastward-trending folds and associated pipelike structures in the Jurassic rocks. The 

eastward-trending folds were first noted in the district in the subsurface (Hilpert and Moench, 1960, 

p. 439). The larger ones have an amplitude of 100 

feet or more, are a mile or more wide, and may be as 

much as several miles long. They are approximately 

parellel to the north margin of a broad highland that 

existed in central and southern New Mexico in Jurassic time (McKee and others, 1956). Probably associated with the eastward-trending folds are several 

near-vertical pipelike structural features in the Morrison Formation (Granger and Santos, 1963; Clark 

and Havenstrite, 1963). These pipes are 100-200 feet 

in diameter, have central cores that have been displaced downward about 25 feet, and have known vertical lengths of 200 feet or more. Similar pipes have 

been described in the Laguna district (Rapaport and 

others, 1952; Hilpert and Moench, 1960; Schlee, 1963) 

where Moench (Hilpert and Moench, 1960) has demonstrated their close association and contemporaneity with 

the Jurassic folds.

Three periods of deformation are recognized in the 

district that have some bearing on the localization and 

distribution of the deposits. The first period was probably during the Late Jurassic and may have extended 

into Early Cretaceous time, the second period was in 

Late Cretaceous to middle Tertiary time, and the third 

period was from middle to late Tertiary and possibly 

extended into Quaternary time.

The first period is thought to be Late Jurassic because it involves rocks of Late Jurassic age and the 

folds are beveled and overlapped by relatively uncleformed beds of the Dakota Sandstone of Early (?) 

and Late Cretaceous age. (See p. 21). The pipes and 

the intraformational folds in the Todilto Limestone 

probably formed at the same time, as they also affect 

only the rocks of Late Jurassic age.

Some domal structural features may also have been 

initiated by this deformation. The Ambrosia dome and 

similar structures involve the Dakota Sandstone and 

younger rocks, so are at least in part post-Dakota in 

age. A thin segment of Westwater Canyon in the Ambrosia dome, as indicated by limited drill-hole data,

has been interpreted to have resulted from initial uplift in Morrison time (Hilpert and Moench, 1960, p. 

439-440). Until more information is available on the 

lower part of the Morrison or the periphery of the 

dome, however, existence of this early uplift must be 

considered rather tentative, as the thin part of the 

Westwater Canyon might represent a local variation in 

the regional sedimentary pattern and bear no relation 

to the dome.

The second period of deformation started in Paleocene or possibly Late Cretaceous time and may have 

extended into Miocene time. It involved the initial 

development of uplifts marginal to the San Juan 

Basin, the deepening of the basin in early Eocene time, 

and the northward tilting of the basin in esrly Eocene 

to Miocene time. The Paleocene or possibly Late Cretaceous age of the initial uplifts is dated by the debris 

of the Animas Formation, of Paleocene and Late Cretaceous age, which spreads southward from the San 

Juan uplift (Kelley, 1955, p. 84). Debris from the 

Zuni and Lucero uplifts is buried, but tl ?se uplifts 

may have originated at the same time as th«. San Juan 

uplift (Hunt, 1965, p. 73 and fig. 54). Deepening of 

the basin took place in late Paleocene or ea.rly Eocene 

time and is dated by the overlap of the San Jose Formation of early Eocene age across nearly vertical Paleocene beds along the front of the Nacimiento uplift. 

Northward tilting of the San Juan Basin followed the 

deposition of the San Jose, which is indicated by the 

reversal of the original southward dip of the beds of 

the San Jose.

The McCartys syncline, as well as the faults, principal features, and folds in the Ambrosia Ls.ke district, 

probably formed during the deepening of the basin. 

The syncline is thought to have formed at this time 

because it is the principal structural feature in the 

Acoma sag; the sag is an intervening structure that 

formed between the Zuni and Locero uplifts at the time 

of basin deepening. The faults, principal fractures, and 

folds probably originated at the same time as the syncline. Their contemporaneity is indicated by the relatively great concentration and displacement of the faults 

along the west limb of the syncline and the progressive 

decrease in numbers and in displacement westward 

(Hunt, 1938, p. 75). Also the rather poorly defined 

northeastward- to northward-trending folds fade out 

westward, parallel the principal fault set, and probably formed at the same time. Moreover, tH fold axes 

and the strike of the major faults parallel the limb of 

the syncline.

The third period of deformation extended from middle to late Tertiary time and possibly extended into 

Quaternary time. It marked the formation of the Kio
PENECONCORDANT DEPOSITS IN SANDSTONE 63

Grande trough, the displacement of the beds of the 

Santa Fe Group, and the eruption of the volcanic rocks 

of the Mount Taylor volcanic field. These events were 

separated from the folding of the McCartys syncline 

by an erosional interval that beveled the gently undulating Cretaceous rocks east of the syncline!. These 

rocks were probably folded contemporaneously with 

the McCartys syncline (Hunt, 1938, p. 75). Although 

this deformation principally involved the area east 

of the Ambrosia Lake district, it undoubtedly also 

involved the rocks in the eastern part of the district. 

This deformation involved renewed movement on some 

fractures and caused the development of some new 

ones, accompanied by minor folding.

MINERALOGY AND FORM

Most mineralogic work has been done on the deposits 

in the Westwater Canyon Member, a lesser amount on 

the deposits in the Brushy Basin Member, and relatively little on the ones in the Recapture Member, but 

all deposits appear to be similiar.

In an interim report, Granger, Santos, Dean, and 

Moore (1961) subdivided the minerals in the Westwater Canyon and Brushy Basin into unoxidized and 

oxidized suites and subdivided the unoxidized suite 

into prefault and postfault assemblages. Each of these 

suites and assemblages is associated with deposits or 

parts of deposits that have characteristic forms and 

characteristic stratigraphic and structural relations. 

This classification has been generally accepted and is 

followed here with some later modifications (Granger, 

1963).

The identified unoxidized minerals are relatively 

few. In the prefault deposits they consist of the ore 

mineral coffinite (U(SiO4 )i-a.(OH) 4j;) and accessory 

pyrite (FeS2 ), jordisite (MoS2 ) (Granger and Ingram, 

1966), and ferroselite (FeSe2 ). The coffinite is exceedingly fine grained and is coextensive with, and intimately associated with, a fine-grained dark-gray or 

brown carbonaceous material that coats the sand grains 

and fills the interstices between the grains. Where it 

is brown, this material has been found to just coat the 

sand grains. A similar gray to black material that is 

generally uranium deficient and lacking in carbon is 

associated with many of the prefault deposits either as 

elongate rounded zones, as much as several feet long 

within or adjacent to ore layers, or as more irregular 

ill-defined zones that generally feather out along crossbedding and occur both above and below ore layers. 

This material appears to be finely disseminated amorphous jordisite, but assays indicate that the gray values 

may partly result from vanadium minerals (Hazlett 

and Kreek, 1963, p. 88; Clark and Havenstrite, 1963,

p. 111-113) and possibly a manganese mineral (Clark 

and Havenstrite, 1963, p. 111-113). This so-called barren material may actually contain small amounts of 

carbon, uranium, and vanadium where encompassed by 

ore (H. C. Granger, oral commun., 1965). In and adjacent to the prefault deposits the accessory mineral calcite occurs as a cement in the sandstone, mostly concentrated at the base of the sandstone units; sonr^ of 

it could be prefault in age, but it probably is larTely 

postfault. Other minerals may be present but have not 

been identified, because of their sparseness and extremely small grain size.

The postfault unoxidized ore minerals are cofl'nite 

and sparse or local occurrences of uraninite (UO2 ). 

The accessory minerals are the vanadium oxides rnontroseite (V2O3 'H2O), paramontroseite (V2O4 ), doloresite (V3O4 (OH) 6 ) (Corbett, 1963), and ha^gite 

(V2O3 'V2O4 '3H2O); and pyrite, some marcasite, and 

barite. These minerals are fine grained but generally 

somewhat coarser than their prefault counterparts. The 

carbonaceous material that is coextensive with the prefault deposits is generally lacking or is quite sparse in 

the postfault deposits; also, the postfault deposits 

reportedly contain somewhat more vanadium am? less 

molybdenum. Calcite occurs as a cement in the randstoiie, as it does in association with the prefault minerals, but only where it occurs as fracture fillings can 

it be dated as postfault.

The oxidized suite of minerals was divided by Granger, Santos, Dean, and Moore (1961, p. 1195) into 

premining and post-mining assemblages. The premining assemblage consisted principally of tyuyamunite 

(Ca(UO2 ) 2 (VO4 ) 2 '5-8H2O) and metatyuyamunite 

(Ca(UO2 ) 2 (VO4 ) 2 -3-5H2O) and, to a lesser extent, carnotite (K,(UO2 ) 2 (VO4 ) 2 '1-3H2O), autunite 

(Ca(UO2 ) 2 (PO4 ) 2 -10-12H2O), met a - autunite 

(Ca(UO2 ) 2 (PO4 ) 2 '8H2O), and other sparse or rare 

minerals. In the oxidized suite, the uranium vanadates 

are the principal ore minerals. They occur as conspicuous canary-yellow coatings on fracture faces: and 

as impregnations in the sandstone where the deposits 

are extensively oxidized. Accessory minerals are n ative 

selenium, cryptomelane, and various iron oxides. Selenium occurs as finely disseminated metallic gray crystals 

in the lower part of the oxidized zone and as finely 

dispersed red crystals in the upper part, mostly on 

exposed rock faces. Cryptomelane occurs locally as 

rather small zones of dense black cement in sandstone, 

as irregular small patches and short fracture fillings, 

and as a replacement in the outer shell of mud stone 

galls. Ferric oxide minerals show as light-b^own, 

orange, and red coatings on the sand grains. Pyrite 

and marcasite are generally absent, but their former
64 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

presence is indicated by pseudomorphs in the ironstained zones.

Kaolinite in the form of white nests or spotty aggregates occurs pervasively in the prefault, postfault, 

and oxidized deposits, as well as throughout most of 

the barren sandstone. The spots range in diameter 

from a fraction of a millimeter to about 2 cm, encompass the sand grains, and are best formed in the 

coarser sandstone. They are generally considered to be 

an alteration product, but the age and relation to ore 

of the alteration are not completely understood. If the 

kaolin was deposited under a single phase of alteration, it probably was introduced prior to oxidation 

and followed the prefault mineralization, as suggested 

by kaolin spots that cement "hydrocarbon-stained111 

sand grain's and that are coated locally in oxidized 

zones by yellow or green stains (Gruner and Knox, 

195T, p. 15).

By their general form and distribution these suites 

and assemblages each make up deposits with distinctive characteristics and show close relations to the 

depth of burial, water table, and degree of fracturing 

and deformation of the host rocks.

Most distinctive and of greatest economic importance are the prefault deposits, which show no obvious 

relation to faults, fractures, or folds. They are tabular 

elongate masses that are primarily stratigraphically

controlled. They range from thin layers a few feet 

in width and length to bodies as much as 30 feet thick, 

several hundred feet wide, and several thousand feet 

long. The long dimensions generally paralM the depositional trends, as marked by current lineations, dip 

of cross strata, and trend of channel scours. The shape 

and position of the bodies are partly controlled by 

intraformational disconformities, particularly those at 

the base of mudstone conglomerates, but away from 

or between disconformities the deposits may have a 

variety of shapes. In vertical section they r .re the most 

irregular transverse to the longest dimension and may 

split and occupy more than one stratigraphic zone, 

feather out into barren material, or end against a 

sharply defined curved surface, generally referred to 

as a "roll."

Because of their tendency to occur in elongate bodies 

and in beltlike clusters, these deposits are referred to 

as "trend" type and the included ore bodies are referred to as "trend" ore (fig. 4).

Postfault unoxidized deposits also are cuite important but less so than the prefault depos: ts. Because 

of structural as well as stratigraphic control, however, 

they are only crudely tabular at best and have more 

irregular lateral limits than the prefault deposits. 

Where stratigraphic controls are dominant the form 

is similar to that of the prefault bodies but where

0 200 

I______I

400 600 FEET 

I______I

FIGURE 4. Trend-type ore deposits (black) in sec. 28, T. 14 N., B. 9 W. Modified from J. B. Squyres (1963).
PENECONCORDANT DEPOSITS IN SANDSTONE 65

fracture control is dominant the bodies conform to the 

fracture pattern and have a variety of shapes, depending on the intensity of the fracturing and the angle 

of intersection with the prefault material. Thus, some 

bodies resemble very irregular or ameba-shaped masses 

and some are distributed through several stratigraphic 

intervals. The thickness of such masses is commonly 

several tens of feet and locally as much as 100 feet 

(fig. 5). The ore bodies are somewhat smaller but in 

places constitute a large part of the entire mass. These 

ore bodies are referred to as "redistributed" or "stack" 

ore, the first term implying that the material has been 

moved and the second term implying that the movement has left a body with a thickness markedly greater 

than that of .the original prefault material, presumably 

at the expense of reduced lateral dimensions.

Post fault deposits are closely associated with, and 

generally merge into, remnants of prefault deposits. 

(See fig. 5.) The process of solution, movement, and 

redeposition has mostly removed material on the updip 

side of the prefault bodies and carried it downdip, 

although local reversals in dip show such bodies on 

the downdip side (fig. 5). The distance the redistributed material has moved is somewhat conjectural, 

but the close association with the prefault material 

indicates that the redistributed material generally has 

moved less than the original lateral dimension of the 

prefault material, distances that probably range from 

inches to perhaps as much as several thousand feet for 

some redistributed materials.

Post fault deposits may be oxidized or unoxidized. 

Where oxidized they occur mostly above the water 

table and generally near the surface, but the mioxidized deposits occur above and below the water 

table. The unoxidized deposits generally lie downdip from an encroaching oxidation front, but from 

place to place the relations are variable, depending on 

the stratigraphic and structural relations, the history 

of ground-water movement, and the depth to the water 

table. In general, however, deposits in the eastern 

and northern parts of the district, where they are 

more deeply buried, are mostly unoxidized, whereas 

in the western and southern parts, where they are 

near the outcrop, they are oxidized along the updip 

margins of the prefault deposits. Details on the general form, and composition of the deposits may be 

found in several reports (Granger and others, 1961; 

Clary and others, 1963; Cronk, 1963; Gould and others, 

1963; MacRae, 1963; Rapaport, 1963; Squyres, 1963; 

Weege, 1963). The broader stratigraphic and structural 

relations are discussed further in this report to provide 

the district setting.

STRATIGRAPHIC RELATIONS OF THE DEPOSITS

Most of the uranium deposits in the Morrison Formation in the district occur in two elongate belts, referred to as the Ambrosia Lake trend and the Poison 

Canyon trend (fig. 6). The controls on these trends 

have been outlined (Hilpert and Moench, 1960) but 

bear repeating. In the Ambrosia Lake trend the deposits are in a sandstone mass that includes the Westwater Canyon Member and the lower part of the 

Brushy Basin Member. The mass is crossbedded sandstone and some discontinuous lenses of claystone and 

mudstone. The central part, which is about 200 or more 

feet thick, is rather uniform in thickness and in lithologic character parallel to the trend, except across the 

Ambrosia dome. (See p. 4, section A-A'.) The r.rea 

just east of the dome that displays relatively few irudstone interbeds is similar to the area farther eastward, but reflects lack of detail as seen from noncore 

drill logs. Sections B-B' and C-C', which cross the 

trend, show that the sandstone mass thins and splits 

into sandstone and interfingering claystone units 

southward and that it thins northward. In addition, 

electric-log data from the drill holes that mark the 

north flank indicate that the sandstone is more uniform in character and contains fewer mudstone units 

than that toward the south. This may indicate a no^thward change to more uniform conditions of sedimentation and to rocks that are less favorable for localization 

or uranium deposits. Somewhat arbitrarily, therefore, 

the sandstone mass is defined by a 150- to 200-footthick complex of fluvial crossbedded sandstone and 

discontinuous lenses of claystone and mudstone. Although the exact limits cannot be determined, the w; dth 

seems to range from about 5 miles in the western part 

to about 2 miles at the eastern end, and it has a known 

length of at least 12 miles. The ends are speculative 

for lack of data. On the west flank of the Ambrosia 

dome the beds are faulted down, and information is 

sparse and not definitive throughout the west half of 

T. 14 K, R. 10 W. Available data suggest, however, 

that the sandstone becomes more uniform in character 

and contains fewer mudstone units westward, siirilar 

to the sandstone of the north flank. At the east end, 

the sandstone thins and grades into mudstone northward 

on the south and west flanks of the San Mateo dome in 

T. 14 N., R 8 W.; southeastward the sandstone appears 

to maintain a rather uniform thickness at least to the 

north-central part of T. 13 N., R. 8 W., but information 

is not available on the detailed lithology. In the northeastern part of this township the sandstone appears to 

interfinger with mudstone, as indicated by limited d~illhole data.
66 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

i ?> o

Vj H a

M n

n\)

: -c V a

i

a) a> *3 H n c ^!

o «

O (A

Q) (0

E E
PENECONCORDANT DEPOSITS IN SANDSTONE 67

The Poison Canyon trend in the Poison Canyon sandstone (in lower part of the Brushy Basin Member) can 

be traced from its west limit, at the outcrop in sec. 14, T. 

13 N., R. 10 W., eastward in the subsurface at least 

through sec. 30, T. 13, N., R. 8 W., and northward 

from the outcrop an uncertain distance in the subsurR. 10 W

face, perhaps as much as several miles. The northern 

extent is uncertain because of a tendency of the sandstone to merge in places with the underlying Westwater Canyon Member and because of some uncertainty 

of correlation between widely spaced drill holes. If the 

sandstone extends as far as T. 14 N., it is most likely

R. 8 W.

EXPLANATION

Outline of ore body or bodies 

(modified from Santos, 1963)

Approximate limit of main orebearing sandstone mass 

Queried where doubtful

Assumed limit of cluster of channeltype sandstone lenses in Poison 

Canyon sandstone of economic 

usage

Outcrop of Poison Canyon sandstone of economic usage

5 MILES

FIGUBE 6. Ore deposits and the limits of favorable belts in the Morrison Formation, Ambrosia Lake district. Geologic cross

sections are shown on plate 4.
68 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

the bed that contains the deposit shown near the south 

end of section C-C' (pi. 4). North of this locality the 

sandstone splits, the upper unit pinching out within 

about 2 miles and the lower unit merging with the 

underlying Westwater Canyon Member within about 

3 miles. Thus, the Poison Canyon sandstone may have 

an extreme width at the west end of about 6 miles 

and an eastward extent of more than 8 miles. There 

is general agreement that the Poison Canyon trend 

generally parallels the sedimentary structures of the 

host sandstone (Dodd, 1956; Granger and others, 

1961; Eapaport, 1963), but the limits of the favorable 

part of the sandstone are uncertain for lack of information and the difficulty of correlating lithologic 

units between drill holes. The fact that the deposits 

parallel the sedimentary structures, however, strongly 

suggests that the deposits may largely be restricted to 

channel-type sandstone. If the deposits are restricted, 

the general limits of such sandstone might be expected 

to be near the deposits, for lack of any other apparent 

control on the linear arrangement. The assumed limits 

of the channel-type sandstones are, therefore, drawn 

near the periphery of the deposits, and these limits 

define a belt of favorable ground about 2 miles wide 

that trends eastward from the outcrop for at least 8 

miles.

In the Ambrosia Lake trend the deposits show a 

general tendency to rise stratigraphically northward 

(Santos, 1963; Hazlett and Kreek, 1963). In the southern part of the trend they generally occur throughout 

the host sandstone but rise northward to where they 

are mostly in the upper part (pi. 4, section B-B' and 

C-C'}. This relation is not fully understood. It could 

have resulted partly from the attitude of the beds at 

the time of emplacement, from the relative thickness 

and change in lithologic character of the host sandstone across the area, from the effects of oxidation 

and redistribution, or more likely, from the hydrologic 

conditions that existed at the time the deposits were 

emplaced.

STBTJCTURAL BELATIONS OF THE DEPOSITS

As outlined earlier, the ore minerals have been subdivided into unoxidized and oxidized suites, and the 

unoxidized suite has been subdivided into prefault 

and postfault assemblages (Granger and others, 1961; 

Granger, 1963). Each of these suites and assemblages 

make up deposits that have characteristic forms and 

characteristic structural as well as stratigraphic relations.

Prefault-type deposits are characterized by coffinite 

associated with finely disseminated carbonaceous material and by tabular e^ngate forms and a notable 

lack of influence by faults, folds, or fractures.

As indicated previously, the trend of th«, principal 

belts in the district are defined largely by prefault deposits. It is notable that these belts and the elongation 

of the individual deposits within them do not follow 

the faults and folds but cross them. (See Granger and 

others, 1961, fig. 2.)

None of the deposits show any direct relation to 

the igneous rocks. As these rocks were erupted during 

the period of deformation of the middle Tertiary to 

late Tertiary they, too, probably had no influence on 

genesis of the prefault deposits.

In the early history of the district the arrangement 

of the known deposits on the flanks of the Ambrosia 

dome suggested an annular pattern and domal control 

of the deposits to some geologists. Subsequent information has shown that the deposits are arranged in 

eastward-trending linear belts that respectively trend 

across the north and south flanks of the dome and 

terminate on its east flank (fig. 6). Available drillhole data show a pronounced thickening of the siltstone of the Recapture Member and a complementary 

thinning of the overlying sandstone of the Westwater 

Canyon Member in the central part of the dome (pi. 4, 

sections A-A' and B-B'), and show that the deposits 

occur in Westwater Canyon where it is about 150-200 

feet thick, but generally are absent where it is less than 

150 feet, thick. These relations indicate tl ^ deposits 

are stratigraphically controlled and are not directly 

controlled by the domal structure. Indirectly, they may 

be controlled, however, by initial uplift of the dome 

in Jurassic time, which may have influenced the sedimentation. (Seep. 62.)

The Jurassic deformation did result in forming 

other structural features; namely, a set of eastwardtrending folds and some associated pipelike collapse 

features and one or more structural depressions. Of 

these features, only the pipelike structures directly 

controlled the emplacement of prefault deposits. In 

them the ore shows local thickening along the annular 

faults (Granger and Santos, 1963; Clark and Havenstrite, 1963). In summary, the prefault, or primary, 

deposits were emplaced after Late Jurassic deformation and prior to the deformation that probably extended from early to middle Tertiary time

The postfault deposits are characterized by a larger 

suite of minerals, including uraninite as well as coffinite, 

some low-valent vanadium oxides, sparse carbonaceous 

material, and a tendency to occur in stackl: ke bodies. 

These deposits have been localized by fractures and 

faults, and in part by folds, as well as by stratigraphic 

structural features. Postfault bodies thicken adjacent
PENECONCORDANT DEPOSITS IN SANDSTONE 69

to faults in many places, and strongly jointed areas 

contain bodies that merge with prefault bodies away 

from the jointed areas (Granger and others, 1961, p. 

1190; Hazlett and Kreek, 1963, p. 87). Examples of 

such deposits are the Section 15, Section 22, Section 23, 

Section 24, and Black Jack 1 mines. The deposit of the 

Hogan mine occurs along the flank of a northeastward-trending anticlinal fold and in close association 

with two fracture sets, and is apparently controlled at 

least in part by both the fold and the fractures (Rapaport, 1963, p. 131-133). The age of these deposits is 

younger than that of the fractures and that of the 

prefault deposits, from which they apparently were 

derived. Their exact age, however, has not been determined ; they could range from early Tertiary to Quaternary, but Pb :U ratios suggest that these deposits are 

post-Miocene in age (H. C. Granger, written commun., 

1966).

The oxidized suite of deposits is characterized by 

the high-valent uranyl vanadates, by their association 

with fractures as well as with sedimentary structures, 

their irregular form, and by their general tendency 

to occur near the outcrop and above the water table. 

They postdate the prefault and postfault unoxidized 

deposits from which they were derived, and some or 

parts of some deposits are in the process of oxidation. 

Examples of such deposits are in the Blue Peak and 

Dog mines (Rapaport, 1963, p. 123, 128) and in parts 

of the Black Jack 1 and Section 15, Section 22, and 

Section 23 mines.

COLOR RELATIONS OF THE HOST BOOKS

The color relations of the host rocks to the uranium 

deposits in this district and others along the southern 

part of the San Juan Basin is incompletely understood, but a brief summary of present information 

may be useful.

For sandstone host rocks associated with deposits in 

the Morrison Formation in the Colorado Plateau, 

the colors have generally been considered to be gray 

or light brown and away from deposits to be dominantly reddish gray. These colors also have been considered "favorable" or "unfavorable" in the search 

for hidden deposits in the sandstone of the Westwater Canyon and Brushy Basin Members in the Ambrosia Lake district, but with notable exceptions.

In a progress report (Granger and others, 1961) the 

favorable colors listed for unoxidized rocks were white 

to light gray (A^-AT), and for weathered rocks were 

very pale orange to dark yellowish orange (10T7? 8/2, 

10T72 8/6,10T72 7/4,10T72 6/6). Rocks colors are from 

the National Research Council "Rock-Color Chart'' 

(Goddard and others, 1948). For the gray rocks, finely

disseminated pyrite was noted, but was found tc be 

largely destroyed in the weathered rocks and replrced 

by films of limonite on the sand grains. These ot^rvations of color were in general agreement with earlier 

findings of Konigsmark (1955) and Young and Ealy 

(1956), except that Granger, Santos, Dean, and Moore 

(1961) found that the colors of some red, as well as of 

limonitic, sandstones are epigenetic and not necessarily original with the host rock. They noted that 1 oth 

colors, in association with ore, occur well below the 

surface and below the water table along fractured 

zones. The epigenetic red colors were listed as generally moderate to dusky red (5R 5/4-5^ 3/4) and 

moderate orange pink to moderate reddish br->wn 

(\QR 7/4, WR 5/4, IOR 6/6, WR 4/6), and the coloring 

agent was identified as hematite film on the Fand 

grains. Near the outcrop they also noted moderate-red 

to very dark red (5R 4/6, 5R 3/4, 5R 2/6) sandstone 

closely associated with low-grade redistributed oxidized 

ores. The association of hematitic colors with deposits 

has also been noted by others (Hoskins, 1963; Gould 

and others, 1963; Rapaport, 1963, p. 131-133).

Gray shades may possibly not always bear a favor- 

'able relation to deposits. In some drill holes in the district, as much as 10-15 miles from the outcrop and 

where the host, rock is as much as 3,000 feet deep, the 

rock is dominantly gray. These holes are more than 

10 miles from a known deposit, but it is not known, 

of course, whether hidden deposits are in the vicinity.

Present information indicates that gray unoxidized 

sandstone 'and limonitic oxidized sandstone generally 

occur in the vicinity of uranium deposits, but that 

locally, especially along fractured zones and in c^ose 

proximity to deposits, hematitic oxidized sandstone 

also occurs. Before more specific conclusions can be 

drawn, more work must be done to determine the history of the oxidation and reduction that has te,ken 

place in the host rocks before, during, and after 

mineralization.

LAGUNA DISTRICT

In the Laguna district 33 deposits or clusters of deposits are listed in the Morrison Formation (pi. 2 

and fig. 7). Of these, 30 are in the Brushy Bq,sin 

Member, 1 is in the Westwater Canyon Member, and 2 

are in the Recapture Member. Of those in the Brrshy 

Basin, 27 are in the Jackpile sandstone of econmic 

usage. Five mines have yielded ore, and two of tlx °,m, 

the large open-pit operations of the Jackpile and Paguate, have yielded 99 percent of all ore produced 

in the district. The Woodrow deposit also is in the 

Morrison Formation, but is discussed later with the 

vein deposits.
70 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

Jackpile sendstoneX^ 

of economic 

ent

EXPLANATION

Outcrop of Jackpile sandstone

of economic usage 

Projected between some exposures

Approximate limits of Jackpile

sandstone of economic usage

Includes projections above surface.

Queried where doubtful

Inferred direction of streamflow

Medium to very large uranium 

deposit or deposits 

Limits ore approximate

Jackpile sandstone 

of economic usage 

absent Small uranium deposit or deposits 

All deposits are in Jackpile sandstone 

of economic usage except those 

designated in the Brushy Basin 

(B), Wesfwofer Canyon (W), 

and Recapture (R) 

Members of the 

Morrison 

Formation

T

SANDOVAL C

R. 6 W. R. 5 W. R. 4 W. R. 3 W.

FIGUEE 7. Part of Laguna district showing the uranium deposits in the Morrison Formation. Modified from S"hlee and

Moench (1961, figs. 4, 10) and R. H. Moench (written commun., 1960).
PENECONCORDANT DEPOSITS IN SANDSTONE 71

The U: V ratio of about 2 million tons of ore shipped 

from three properties averaged 5:2 and ranged from 

3:1 to 1:2. Except for a few thousand tons, this ore 

came from the Jackpile mine. During the 1954-58 period about 2.3 million tons of ore shipped from four 

properties averaged 0.9 percent and ranged from 0.6 to 

10 percent lime. Except for a few hundred tons from 

one property that averaged 9 percent lime, nearly all 

shipments averaged less than 2 percent.

STBATIGBAPHT

Between the Ambrosia Lake and Laguna districts, 

the Morrison Formation is deeply buried in the McCartys syncline. Where it crops out immediately north 

of Laguna it has about the same thickness as in the 

Ambrosia Lake district, but is composed mostly of a relatively thick Brushy Basin Member and markedly 

thinner Westwater Canyon and Recapture Members. 

The stratigraphic relations of the members between 

the two districts are shown in figure 8. The Morrison 

attains its maximum thickness of about 600 feet in 

the central part of the Laguna district from where it 

thins laterally. Southward it is beveled under the 

pre-Dakota erosion surface, and it is missing from the 

southern part of the district. (See Moench, 1963a, b; 

1964a, b; Moench and Puffet, 1963a, b; Moench and 

others, 1965; Schlee and Moench, 1963a, b.)

The lowermost member, the Recapture, ranges in 

thickness from 0 to about 100 feet and probably averages about 25 feet. It consists of alternating grayishred and greenish-gray mudstone, siltstone, sandstone, 

and a few thin beds of limestone. It is lithologically 

similar to the Recapture in the Ambrosia Lake district. 

Locally, in the eastern part of the district, it contains 

two uranium deposits in a sandstone bed in close association with a pocket of coalified plant debris.

The overlying Westwater Canyon Member ranges in 

thickness from 0 to more than 100 feet and averages 

about 50 feet. It is thickest in the northern part of

Northwest

500

AMBROSIA LAKE 

DISTRICT Base of Dakota

the district from where it thins southward. Lccally 

it grades into the Recapture Member. It consists of 

grayish-yellow to very pale orange fine- to coarsegrained friable sandstone, structurally similar to the 

Westwater Canyon in the Ambrosia Lake district. It 

contains two small deposits at the outcrop.

Overlying the Westwater Canyon is the Brishy 

Basin Member, which composes most of the Morrison. 

From the central part of the district, where it is more 

than 300 feet thick, it thins laterally, but most markedly southward, and is cut out in the southern part 

of the district under the pre-Dakota erosion surface. It 

consists of grayish-green bentonitic mudstone and 

some sparse thin beds of clay-rich sandstone. In the 

lower part it contains lenses of sandstone similar to 

that of the Westwater Canyon. These are generally 

less than 20 feet thick, but are locally as much as 85 

feet thick. In the central part of the district, it contains, 

in its upper part, the Jackpile sandstone of ecoromic 

usage (Hilpert and Freeman, 1956), which is the 

main ore-bearing unit. The following description of it 

is largely taken from Schlee and Moench (1961).

It is a tabular body about 15 miles wide and 35 

miles long that extends from the vicinity of Laguna, 

northeastern Valencia County, northeastward to the 

vicinity of Mesa Prieta, southwestern. Sandoval County fig. T). From a maximum thickness of about 200 

feet a few miles north of Laguna, it tapers to its 

margins and, to the northeast, splits into two fingers.

The Jackpile is a yellowish-gray to white finable 

fine- to medium-grained fluvial sandstone that generally grades from coarser grained subarkosic material 

at the base to finer material at the top. The cementing material is principally calcite in the lower part 

and clay in the upper part. At the top the interstices 

of the sandstone 'are filled with white clay which is 

mostly kaolinite and probably a product of weathering 

of interstitial debris under the pre-Dakota erosion 

surface prior to Dakota deposition (Leopold, 1943;

J Morrison Formation-

(not exposed at surface) 

Sandstone (flattened)

Uranium 

deposits

LAGUNA 

DISTRICT Southeast

 xPoison Canyon sandstone of ecoTTomicljsage

^T~ ~-~T ~ ~ ~-r r~- Brushy Basin Member

FIGURE 8. Relations of the principal stratigraphic units of the Morrison Formation between the Ambrosia Lake and Laguna

districts.
72 URANIUM HESOURCES OF NORTHWESTERN NEW MEXICO

Schlee and Moench, 1961). The unit is generally thin 

to thick bedded and massive, but festoon crossbedding 

is well formed in sets as much as 4 feet thick. The 

crossbedding planes indicate that the sediments were 

transported northeastward parallel to the long axis of 

the unit. The truncation of the unit at the top under 

an unconformity indicates that former dimensions 

were larger than at present, but the former extent 

may not have been much greater, as indicated by the 

apparent thinning by loss of beds at the base as well 

as by the wedging out of the unit in places below 

the unconformity. The Jackpile sandstone contains 

nearly all the known deposits in the Brushy Basin 

Member and all the principal deposits in the Morrison 

Formation in the district (fig. 7).

STRUCTURE

The Laguna district is mainly on the east limb of 

the McCartys syncline, which dips gently northwestward into the San Juan Basin (fig. 3). On the east 

flank of the district the beds are downdropped along 

a north-trending faulted monocline into the Rio 

Grande trough. The volcanic rocks of Mount Taylor 

cover the western side of the district, and numerous 

volcanic centers, flows, dikes, and sills are distributed 

throughout the district and mark the northern part 

of the Datil volcanic field. As in the Ambrosia Lake 

district, three periods of deformation are recognized: 

Late Jurassic to Early Cretaceous, Late Cretaceous to 

middle Tertiary, and middle Tertiary to late Tertiary 

or Quaternary. The Jurassic deformation produced 

broad gentle folds, associated pipelike structural features, and a structural basin, all similar to those in 

the Ambrosia Lake district. These structural features, 

which are described by Moench (1963c, p. 159), are 

shown in figure 9.

"The Jurassic deformation produced two sets of 

folds of low amplitude, one trending east to northeast, the other trending north-northwest * * *. These 

folds are known to predate the Early Cretaceous Dakota 

sedimentation because folded Jurassic rocks are unconformably overlain by less-deformed beds of the 

Dakota. Jurassic folding was accompanied by lateral 

flowage of unconsolidated limestone of the Todilto 

Formation into the synclines, producing the variety of 

intraformational flowage folds that are characteristic of 

that unit and accounting for the thickening of limestone in the synclines. Folding was also accompanied 

by slumping and internal faulting of unconsolidated 

clastic sediments and by the formation of peculiar 

cylindrical subsidence structures or sandstone pipes 

(Hilpert and Moench [1960], p. 437-443). Folding 

also markedly influenced sedimentation. The fluvial

Jackpile sandstone, for example, seems to have accumulated in a broad, east- to northeast-trending syncline that deepened and expanded during sedimentation (Schlee and Moench [1961], p. 147-150)."

The Late Cretaceous to middle Tertiary tilting is 

dated from outside the district by the same evidence 

as listed under the Ambrosia Lake district (p. 62). 

This deformation caused the tilting of the beds to the 

northwest.

The third period of deformation, from middle to 

late Tertiary time, and possibly extending into Quaternary time, marked the subsidence and sedimentation 

of the Rio Grande trough and produced the northtrending normal faults, the faulted monocline along 

the west margin of the trough, and the joints in the 

sedimentary rocks (Moench, 1963c). The fracturing 

was accompanied by the emplacement o* numerous 

dikes and sills, for these intrusives occupy joints of 

the fracture system and sills are cut by joints and 

faults of the same system (Moench, 1963c, p. 159).

The fracture system in the main part of the Laguna 

district probably is younger than that in the Ambrosia 

Lake district. In the latter district the fractures are 

closely associated with the formation of th<\ west limb 

of the McCartys syncline, a structural feature that 

probably formed early in the history of tin San Juan 

Basin. The fractures in the Laguna district are apparently younger and occurred during formation of 

the Rio Grande trough, a Basin and Rang0, structural 

feature.

MINERALOGY AND FORM

Most deposits in the district occur above the water 

table and most are oxidized to some extent, possibly 

more so than most descriptions have implied, for 

metallurgical tests of the ores from the Jackpile and 

Paguate deposits indicate about 75 percent of the uranium is oxidized (Kittel, 1963, p. 170).

Coffinite is the principal uranium mineral that is 

primary and certainly unoxidized. It is associated with 

the oxidized minerals, with sparsely disseminated 

pyrite and some marcasite, and with minute quantities 

of other metallic sulfides. The coffinite-bear'ng material 

contains uraninite, which might be primary, but could 

also be secondary after oxidized coffinite (Granger, 

1963, p. 31). Vanadium generally occurs with the uranium in the ratio of about 1:2 in the ores, but few 

primary or unoxidized vanadium minerals have been 

identified, probably because of their extreme fineness. 

Most of the vanadium probably occurs in the unoxidized state in vanadium-bearing mica and clay.

The principal oxidized uranium minerals are the 

vanadates tyuyainunite and metatyuyamunite, the 

phosphate autunite, and the silicate uranophane
PENECONCORDANT DEPOSITS IN SANDSTONE 73

(Ca(UO2 ) 2SiO3 (OH) 2 -5H2O). The vanadates occur 

chiefly as tabular bodies and small concretionary 

masses within the partly oxidized ore bodies and 

locally as fracture fillings in silicified fossil logs and 

in a diabase dike that intrudes the Jackpile deposit. 

Autunite and less common phosphates also coat fracture faces; the autunite is most abundant in the borders of the diabase intrusive. A more complete list

of the uranium-bearing minerals and associated gar gue 

minerals is given by Granger (1963, p. 32), and additional identified uranium-bearing minerals are listed 

by Kittel (1963, p. 170). Most deposits are closely associated with coextensive fine-grained carbonaceous 

material similar to that associated with the deposits 

in the Ambrosia Lake district. A few small deposits 

are associated with coalified plant debris.

/~"\ Southern limit of Jackpile

\ sandstone lasione of OTeconomic usage.

Jurassic rocks undifferentiated Pre-Dakota folds

Showing trace of axial plane. Snorter arrow 

indicates steeper limb. Dashed where conceo/ed by Cretaceous or younger rocfcs

107°30'

5 MILES

Jurassic and Triassic 

rocks undifferentiated

Contact

Rose compass diagram

Showing bearings of axes of intraformotiona/ folds in Todilto Limestone

Uranium mine Uranium prospect

FIGIIRE 9. Pre-Dakota structural features and south limit of Jackpile sandstone of economic usage, Laguna area. Simplified

from R. H. Moench (written commun., 1959).
74 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

Most of the deposits are crudely tabular and have 

a tendency to occur in one or more layers, as elsewhere, but are generally more irregular in outline; 

only the larger ones are notably elongate. The layers 

range in thickness from only a few inches to as much 

as 20 feet and occur in multiple units that are as much 

as 50 feet thick. In lateral dimensions they range from 

a few feet to several thousand feet,. The two largest, 

the Jackpile and Paguate, are elongate, the Jackpile 

averaging about 2,000 feet in width and having a 

length of about 7,000 feet, and the Paguate averaging 

about 1,500 feet in width and having a length of 

about 2 miles (fig. 7). Peculiar to the lower grade 

parts of some cf the deposits are rodlike structures 

composed of uraniferous carbonaceous material, which 

coats sand grains and locally thoroughly impregnates 

the sandstone. These rods are roughly normal to bedding (Hilpert and Moench, 1960, p. 453; Moench, 

1963c, p. 162, and figs. 4, 5).

STEATIGEAPHIC RELATIONS OF THE DEPOSITS

Most of the deposits, including all the larger ones, 

are in the Jackpile sandstone and largely concentrated 

within the thicker part, where it ranges in thickness 

from about 100 to 200 feet. The margins of the deposits locally are controlled by mudstone contacts, bedding planes, diastems, and other sedimentary features, 

but in general the deposits figuratively float in the 

sandstone units within the lower and middle parts of 

the host sandstone (Hilpert and Moench, 1960, p. 451; 

Kittel, 1963, p. 170), and the Paguate extends from 

the lower two-thirds at the southeast end of the deposit to the upper third at the northeast end where 

it apparently is beveled under the pre-Dakota erosion 

surface (Kittel, 1963, p. 170 and fig. 4). The principal 

cluster of deposits in the Jackpile sandstone is elongate 

northeastward (fig. 7) and conforms to the dominant 

dip direction of the crossbedfling and to the axial 

trends of the Jackpile sandstone body. Thus, the deposits show a direction relation to both broad and 

detailed stratigraphic features.

STRUCTURAL RELATIONS OF THE DEPOSITS

The uranium deposits were both indirectly and 

directly controlled by structures formed during Late 

Jurassic deformation, but obviously were not controlled by structures formed during Tertiary or later 

deformation, except for the oxidized material.

Indirect control is shown by clustering of the deposits in the central part of the Jackpile sandstone 

(fig. 7). The Jackpile occupies a structural trough 

that formed before, during, and ai'ter sedimentation, 

as evidenced by the abnormal thickness of the Morrison Formation along the axis of the Jackpile sandstone, by the pre-Dakota folds along tl °> southeast 

margin, one set of which is parallel to the axis of the 

Jackpile sandstone (fig. 9), and by the beveled southeast and northwest flanks of the Jackpile sandstone 

under the pre-Dakota erosion surface (Schlee and 

Moench, 1961, figs. 3, 4, 11).

Direct control is shown by the occurrence of black ore 

in the boundary ring fault of a sandstone pipe in the 

Jackpile mine (Hilpert and Moench, ]960, fig. 8; 

Moench, 1963c, fig. 2 and p. 163). Ore also occurred in 

the "Wbodrow pipe, but the genesis of this deposit is 

controversial; it is discussed with the vein deposits. 

Locally there is evidence that the Juriassic folds mav 

have exerted some direct control on localization of deposits. The northern part of the Jackpile ore body aj> 

parently trends northward along the axis of a preDakota anticline, which is one of a set of such folds. As 

this trend is almost normal to the axis of the northeastward-trending sedimentary structures and to the 

northeastward elongation of the Paguate deposit, probably the pre-Dakota anticline exerted some control on 

the localization of the Jackpile deposit (Hilpert and 

Moench, 1960, p. 450-451, and fig. 9; Moench, 1963c, 

p. 163-164).

The Tertiary structures show no obvious control 

over the primary uranium deposits, and are apparently younger than the deposits. This is demonstrated 

by the relations of the deposits to the diabasic dikes 

and sills and to the fracture systems.

The diabasic dikes and sills, which protably are the 

oldest recognized intrusives in the distrot (Hilpert 

and Moench, 1960, p. 444), intrude and displace the 

Jackpile deposit (fig. 10) and other nearby deposits 

in the Todilto Limestone. If these intrusives are the 

same age as the fracture system, as indicated, both the 

fracture system and the intrusives are younger than 

the deposits and could not have influenced their emplacement. This relation is confirmed by the lack of 

any convincing alinement of the deposits with nearby 

fractures (Moench, 1963c, p. 161).

Oxidized uranium minerals occur along joint faces 

and in the chilled borders of diabasic intrusives, but 

the field evidence indicates that the minerals were derived from earlier black ores (Moench, 19"3c, p. 161). 

No postf ault unoxidized ores similar to those described 

by Granger, Santos, Dean, and Moore (1961) (see 

p. 63) have been recognized in the Lag'ina district.

Available evidence indicates that the deposits in the 

Laguna district were emplaced closely following or 

during Jurassic deformation, prior to development of 

the Late Cretaceous erosion surface, and prior to Late
PENECONCORDANT DEPOSITS IN SANDSTONE 75

5985' 

5980' 

5 FEET

FIGURE 10. Displacement of Jackpile uranium deposit by 

diabase sill. Geology by R. H. Moench. Datum is approximate 

mean sea level.

Cretaceous or early Tertiary tilting of the southern 

part of the San Juan Basin. As the deposits are generally widespread and show little or no obvious relation to fractures, the assumption is that they were 

emplaced from solutions that moved laterally and perhaps under a water table. If so, the local transection of 

deposits across the Jurassic folds (Hilpert and Moench, 

1960, fig. 15) can be explained by emplacement during 

or after folding. Their pre-Cretaceous age also is supported by the apparent beveling of the Paguate deposit under the pre-Dakota, or Late Cretaceous, erosion 

surface (see p. 74) and by the absence of known 

uranium mineralization of the rocks of Cretaceous 

age in the district. Moreover, if the rodlike ore Structures in the Jackpile sandstone ore bodies were formed 

by gravity control of the mineralizing solutions, as determined by Moench (1963c, p. 161-162), they would 

be expected originally to have had a vertical orientation. As they appear to be approximately normal to 

the bedding of the Dakota Sandstone, a relation confirmed by one measurement, and as the ore layers of 

the Jackpile conform to the dip of the Dakota Sandstone, the uranium deposits apparently were emplaced prior to tilting of the Dakota Sandstone.

Conclusions are that Late Jurassic (pre-Dakota) deformation indirectly controlled the emplacement of the 

deposits and likely caused some direct control on their 

emplacement. The emplacement probably occurred during or shortly after the Jurassic deformation and before the deposition and tilting of the Dakota Sandstone. Post-Dakota structures exerted no control on 

the primary deposits, but did localize some secondary 

minerals.

329-381 O 6!

COLOB RELATIONS OF THE HOST ROCKS

Except for the Jackpile sandstone, the colors of the 

ore-bearing sandstones in the Morrison Formation in 

the district are generally light gray (NT) in the 

proximity of deposits, and range from light gray to 

very pale orange (10T7? 8/2) to locally dusky yellow 

(5T 6/4) away from deposits. The Jackpile sandstone mostly is very light gray to white (N 7-N 9). The 

lighter shades are at the top, the result of kaolirization by weathering of feldspar minerals under the 

pre-Dakota erosion surface (Leopold, 1943; Schlee and 

Moench, 1961; Moench, 1963c, p. 165). Darker shades, 

medium light gray (NQ) to dark gray (#3), generally are closely associated with the deposits an<? result largely from the presence of carbonaceous material 

(Hilpert and Moench, 1960, p. 446).

Reddish hues, which generally have been famd 

away from deposits (p. 69), occur only sparsely in the 

Laguna district.

GALLUP DISTRICT

About 30 deposits or clusters of deposits in sandstone are listed in the Gallup district (pi. 1). Most of 

them are in the Westwater Canyon Member, many are 

in the Brushy Basin Member, and two are recordei in 

the Recapture Member. Seven of the deposits or 

clusters have been mined, five of them are partly or 

entirely in the Westwater Canyon and two of them 

are in the Brushy Basin. Most of the ore from the 

Church Rock mine was produced from a body in the 

Dakota Sandstone, and a relatively small part was obtained from bodies in the Westwater Canyon Member.

The ore shipments made in the 1953-58 period 

totaled about 3,800 tons and had an average U:V 

ratio of 1:1 and a range among mining properties of 

from 1:1 to 1:2. Also, from four properties, about 

3,500 tons of ore averaged 1.6 percent lime content 

and ranged from 0.8 to 17 percent. The 17-percent 

lime content represents only a few tons of ore. All the 

ores were partly oxidized.

STRATIGRAPHY

In the district the Morrison Formation crops out 

around the west and north flanks of the Zuni uplift 

from about 30 miles south of Gallup, where it pinches 

out, northward and eastward to the Continental Divide, 

at the east side of the district. In the western part 

of the district, the Recapture Member grades and 

intertongues with the Cow Springs Sandstone. From 

the general vicinity north of Thoreau the Recapture 

shows an increasing amount of light-gray Cow Springs 

material westward until it "sands up" and loses its
76 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

identity immediately south of Gallup. From the northwest end of the Zuni uplift for 10-15 miles eastward, 

identification of the Recapture-Westwater Canyon contact is rather arbitrary or difficult in many places because of the grading and intertonguing relations with 

the Cow Springs.

The Recapture Member in the district is a sequence 

of interbedded siltstone, mudstone, and sandstone units 

that generally range in thickness from a foot or so 

to several tens of feet. The units generally consist of 

reddish-brown and grayish-red beds that alternate 

with light-gray and greenish-gray beds. Most sandstone 

beds are less than 15 feet thick and tend to be flatbedded and have small-scale crossbeds, except where 

they intertongue with the Cow Springs. In such places 

the bedding locally shows sweeping cross laminations 

as well as some channel scours. This bedding indicates 

a mixture of eolian and fluvial processes. Coalified 

plant debris is present in the Recapture, but mostly 

in local and widely scattered localities.

The Recapture probably is about 500 feet thick at 

Twin Buttes Wash about 25 miles northwest of Gallup 

(Alien and Balk, 1954, p. 155-156; L. C. Craig, oral 

commun., 1965). Eastward it thins markedly within 

a few miles and, along and near the outcrop between 

Gallup and the east side of the district, is 150-300 

feet thick but averages about 175 feet. Most of the district is in the conglomeratic facies (Craig and others, 

1955, fig. 22). Dip directions of the cross laminae indicate a northeast component and a southwest source (L. 

C. Craig, written commun., 1961).

Between Gallup and the Continental Divide the 

Westwater Canyon Member ranges in thickness from 

175 to 275 feet and probably averages about 225 feet. 

In most places it contains one or more mudstone units 

that range from mere partings in the sandstone to 

units as much as 20 feet thick. These units have rather 

limited lateral continuity and only some of the thicker 

ones may extend as much as a mile or more before 

grading out into sandstone or being cut out at the 

base of overlying sandstone units (fig. 11). Few 

data are available on local sedimentary trends within 

the sandstone units. Sharp (1955, p. 8) commented 

that studies on crossbedding indicate that the sedimentary trend in the Church Rock area ranges from 

east-northeast in the west half to southeast in the 

east half, but he did not indicate the extent of the 

studies or the units concerned. The available data 

indicate that the Westwater Canyon in the district is 

rather uniform in thickness and lithologic character 

along outcrop and extends from outcrop for at least 

several miles.

The Brushy Basin Member in the district generally 

ranges in thickness from 40 to 125 feet f-nd averages 

about 75 feet. The range in thickness of tl °> member is 

caused mostly by its intertonguing and grading at 

the base with the Westwater Canyon but partly by its 

beveling southwestward under the pre-Dakota erosion 

surface. The Brushy Basin consists of varicolored claystone and mudstone interbedded with some sandstone. 

The principal sandstone beds, which are lithologically 

similar to those of the Westwater Canyon, range in 

thickness from about a foot to as much ac 60 feet, but 

probably average less than 25 feet. Thinner sandstone 

beds are present, but are generally fine grained and 

calcareous and grade laterally and upward into mudstone and claystone.

Two sandstone beds in the Brushy Basin contain the 

principal deposits, the Black Jack 2 in the eastern part 

of the district and the Foutz 3 in the Church Rock 

area in the western part of the district. Hoskins (1963, 

p. 49) described the host sandstone of the Black Jack 

2 as ranging in thickness from 60 feet st the northwest end of the deposit to 18 feet at the south end and 

as pinching out from 2 to 3 miles east of the mine. He 

noted the sandstone is tan to dark brown except along 

the northeast edge of the deposit where it is brick 

red. He also stated that the ore follows an ancient 

stream pattern, which implies that the sedimentary 

lineation is southeastward because of the elongation 

of the deposit in that direction (Hoskins, 1963, p. 49, 

and figs. 2 and 3). He did not indicate th^ western extent of the host sandstone.

The host sandstone of the Foutz 3 deposit is in the 

approximate center of the Brushy Basin Member. 

Away from the deposit the lateral extent and general 

stratigraphy of the unit are largely taken from Sharp 

(1955), who referred to it as the "upper ore sand" of 

the Westwater Canyon Member. From measured sections along the outcrop he extended it eastward 

through the southern part of T. 16, N., R. 16 W., and 

northward from the southernmost exposures by at 

least 2 miles (Sharp, 1955, figs. 3-5). More northern 

segments of this unit, or its stratigraphic equivalents, 

may be the principal sandstone unit shown in the 

Brushy Basin in figure 11. Throughout this general 

area the unit ranges in thickness from 0 to 45 feet and 

averages about 25 feet. Where it is light brown or 

gray it composes an eastward-trending zone about 1 

mile wide and more than 6 miles long (Sharp, 1955, 

fig. 2). The eastward elongation of this zone may conform with the general dip direction of the crossbeds 

(Sharp, 1955, p. 8).

Konigsmark (1955, p. 8 and fig. 1) showed several 

sandstone units at the top of the Brushy Basin at the
PENECONCOKDANT DEPOSITS IN SANDSTONE 77

outcrop in the Church Rock area and in the western 

part of T. 15 N., R. 14 W., but he gave no detailed 

information.

STBUCTTIEB

The Gallup district is largely along the southwest 

flank of the San Juan Basin, where the beds dip gently northward from the Zuni unlift. In the southwestern part of the district the beds warp around 

the northwest end of the uplift and clip steeply westward into the Gallup sag, a depression that occupies 

a structural position between the Defiance and Zuni 

uplifts similar to the position of the Acoma sag between the Zuni and Lucero uplifts to the southeast 

(fig. 3). Principal folds are the Pinedale and Nutria 

monoclines on the north and west flanks, respectively, 

of the Zuni uplift. The development of these folds, 

which are 10-15 miles long, probably started about 

the same time as that of the uplifts (Kelley, 1955, p. 84). 

Locally the beds are fractured, but faults are sparse and 

the displacement along them seldom exceeds a few tens 

of feet. Little detailed information has been compiled 

on the fractures in the district. One vertical set trends 

northeastward through the Church Rock area; it may 

be part of the set having a similar trend that Kelley 

(1955, fig. 2) showed northeast of Gallup. Hoskins 

(1963) noted that in the eastern part of the district a 

set 4f fractures strikes N. 55° W. and dips steeply 

northeast.

The history of deformation in the district for the 

Late Jurassic and early Tertiary events is probably 

similar to that in the Ambrosia Lake district; this 

premise is based on the proximity of the two districts and the similarity of their regional structural relations. No late Tertiary deformation, however, is 

recognized in the district. Such deformation, which involved the development of the Rio Grande trough to 

the east, possibly died out westward within the Ambrosia Lake district (p. 62). If so, most fractures in 

the Gallup district may be related to the deepening of 

the San Juan Basin and development of the monoclinal folds in the period of deformation of the Late 

Cretaceous to early Tertiary.

MINERALOGY AND HABITS

Information on the mineralogy of the deposits is 

fragmentary, but probably is similar to that on the 

deposits in the Ambrosia Lake district. The largest 

deposits, such as the Black Jack 2 and the Church 

Rock, and most of the smaller ones are closely associated with fine-grained disseminated carbonaceous material in a manner similar to the relation of the deposits in the Ambrosia Lake and Laguna districts. 

Some deposits are associated with coalified fossil plant

debris. The large deposits and their satellites are composed mostly of black ores, which from place to place 

are probably prefracture, postfracture, or a combination of both, similar to the prefault and postfault deposits at Ambrosia Lake. The Black Jack 2, for example, is probably prefracture and largely unoxidized, 

although the tan and brown hues of the host sandstone indicate some oxidation (Hoskins, 1963, p. 49). 

This deposit comprises a cluster of bodies in the 

Brushy Basin Member that has been cut by a set of 

fractures that strike N. 55° W., but apparently with 

little effect on the deposit (Hoskins, 1963).

The Church Rock, which was flooded and abandoned 

in 1963, included the largest of the deposits mined 

from the Morrison in the western part of the district. 

This property included one ore body in the upper part 

of the Westwater Canyon Member and another, about 

200 feet above, in the Dakota Sandstone. The general 

information on the geologic relations of the ore be dies 

in this property is largely from Dean Clark (oral 

comniun., 1965) and R. K. Pitman (oral commun., 

1965). Both ore bodies occurred below the water tr.ble, 

which was about 100 feet below the shaft collar, and 

the bodies were largely controlled by a strong steeply 

dipping fracture system that trended northeastward 

and along which the ore was mostly redistributed. The 

largest ore body in the Dakota Sandstone was roughly 

sombrero shaped and oriented northeastward along 

the fractures. Within the fracture set it was as n^uch 

as 25 feet thick, but laterally away from the set it 

pinched abruptly to one or more layers which at nost 

were only a few feet thick. The deposit in the Westwater Canyon contained several small ore bodies, distributed rather erratically along the fracture system, 

within a stratigraphic interval of 545-685 feet below 

the shaft collar. Laterally these bodies graded abruptly 

into thin blanketlike layers that were not economically 

minable.

Little information is available on the ore, but the 

ore in the Dakota seems to have been postfault and 

redistributed, and the ore in the Westwater Car yon 

prefault. When the mine was visited during its closing 

stages, H. C. Granger (written commun., 1966) observed that the ore in the Dakota was light colored 

and resembled some postfault ore in the Ambrosia 

Lake district; he found that along the upper level in 

the Westwater Canyon the ore remnants were black and 

identical to prefault ore at Ambrosia Lake, and that 

some oxidation extended at least to that level. Little 

information is available on most of the other deposits 

in the district, largely because they are in the subsurface and have not been developed.
78 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

mill

Y 

uojieuuoj UOSUJOIAI

I 

I

BAoqe panui;uoo
Base of Dakota Sandstone (flattened)

1 MILE

I_______|_______|_______|_______| 

VERTICAL EXAGGERATION X10

EXPLANATION

Mudstone Siltstone Sandstone Uranium deposit

Abouf 0.02 percenf

or more etJ'

Contact 

Dashed where inferred

FIGURE 11. Geologic sections in the western part of the Gallup district showing the stratigraphic relations of the uranium deposits to 

Formation and the Cow Springs Sandstone. Compiled from electric logs in 1957-59, provided by courtesy of Phillips Petroleum Co. 
80 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

Most deposits at the outcrop are partly oxidized. 

The largest of these, the Foutz 3, was examined 

shortly after it was mined. The unusual structural 

relations of this deposit and the effects of Recent 

oxidation in part of it justify a brief description.

The Foutz 3 occurs at the north end and at the 

crest of a ridge capped by claystone of the Brushy 

Basin Member. Just under this claystone the deposit 

occurs at, and near, the outcrop of a 25-foot-thick sandstone unit of the Brushy Basin (fig. 12). A purple 

hematitic envelope encompasses the deposit and includes a central zone composed of several light-brown, 

light-gray to white, and purple subzones. These subzones are crudely layered, and are interfingered and 

intergraded. The zone and the contained deposit are 

partly controlled by a set of steeply dipping fractures 

that strike N. 30° W.

In the southern part of the deposit the ore occurred 

as a tabular mass at the base of a cluster of fractures 

that individually have strike lengths of less than 30 

feet and that die out about 1-3 feet below the stope 

roof. The ore occurred mostly below the fractures and 

only locally may have been influenced by them. In the 

northern part of the deposit the fractures are more 

continuous, and a few have a strike length of as much 

as 80 feet and a vertical extent of as much as 15 feet. 

Below the floor of the workings, some of the fractures 

probably extend to the base of the sandstone unit. The 

ore bodies along the fractures were crudely elongate 

and generally averaged a few feet in width, were as 

much as 15 feet high, and ranged from several feet to 

as much as 100 feet in length.

Few uranium minerals were discernible in the mine 

when it was examined, in spite of widespread oxidation. Radiometric scanning indicated that the uranium 

was concentrated within the purple hematitic envelope 

but showed that it had no particular or consistent preference for the individual color zones. Yellow oxides, 

where observed, occurred as rather sparse 'bloom" in 

the darker brown zones or limonitic material. Channel 

samples taken across the ore zone in the southern 

stope area are apparently typical of the ore, as they 

show no marked differences in the contents of uranium, 

sulfur, and iron from the pulp sample of the ore:

Ore pulp 

sample

Channel samples Local 

sample

245106 239600 239601 239602 239607

Uranium »__ 0.17(f)

Sulfur 2 ..... .12

Iron 3 .___ 1.5

0. ll(f) 0. 59(v) 0. 28(v) 0. 70(v)

.10 .03 .24 .11

1. 5 1. 5 3.0 10. 0

 Fluorimetric (f) and volumetric (v) analysis by E. J. Fennelly, J. P. Schuch, J. S. 

Wahlberg, and B. P. Cox. 

8 Gravimetric analysis by G. T. Burrow. 

> Semiquantitative spectrographic analysis by R. G. Havens.

Relation of the joint pattern to the surfrce indicates 

the joints formed by surface slumping. Farthest from 

the outcrop the fractures appear only at the top of the 

sandstone unit and appear to be incipient, but they 

progressively become more extensive and deeper near 

the outcrop. (See fig. 12, section A-A'.) Confirming 

this relation is the greater degree of oxidation along 

the principal fractures and less conspicuous oxidation 

in the southern part of the mine. The conclusion is that 

the deposit predates the fractures except for the oxidized parts, and that the oxidation is quite late and 

has followed Recent surficial slumping and exposure 

by erosion.

The uranium in the deposit is apparently in a finely 

disseminated uranium vanadate. A polished section of 

sample 239607 (Detail section E, fig. 12) shows finegrained interstitial specks of a canary yellow mineral 

which, from an autoradiograph (fig. 13)', is indicated 

to be the principal uranium-bearing mineral. If uraninite or any other low-valent uranium minerals are 

present the concentration is too low to produce a 

recognizable X-ray pattern (T. E. Botinelly, written 

commun., March 15, 1966).

STBATIGBAPHIC AND STRUCTURAL RELATIONS OF THE DEPOSITS

In the Gallup district the uranium deposits are 

widely scattered within the Westwater Canyon and 

Brushy Basin Members and locally show a close relation to either stratigraphic or tectonic structural features. The Black Jack 2 deposit in the eastern part of 

the district shows a close relation to the crossbedding 

and coarseness of the host sandstone and to the presence in it of mudstone units, but it shows no apparent 

relation to fractures (Hoskins, 1963). It occurs in a 

sandstone unit near the base of the Brushy Basin, in 

the same stratigraphic position as the Poison Canyon 

sandstone, but as a stratigraphically discrete unit. In 

the Church Rock area, where most of the known deposits occur, they are widely distributed stratigraphically 

(fig. 11), and many show a close association with 

northeastward-trending fractures. At least parts of 

these deposits may also show a close relation to sedimentary structures, but detailed information is not 

available.

As indicated previously, the deposits ir the Church 

Rock area are probably prefracture away from fractures and postfracture along fractures. O:>0< deposit is 

partly Recent in age where it is associated with Recent 

surficial slumping and fracturing. The prefracture 

deposits are probably the same age as the prefault 

deposits in the Ambrosia Lake district. As the fracturing in the Gallup district may have be^.n restricted 

largely to early Tertiary deformation (Paleocene to
PENECONCDRDANT DEPOSITS IN SANDSTONE

early Eocene), the deposits probably were emplaced 

after Late Jurassic deformation and prior to early 

Eocene. The postfracture deposits are less definite in 

age. They might be as early as Paleocene and could 

be as late as Recent.

COLOR RELATIONS OP THE HOST ROCKS

Color relations of the host rocks to the deposits are 

quite similar to those in the Ambrosia Lake district. 

The deposits generally are associated with sandstone 

that is light gray or very pale to dark yellowish 

orange and that has a more pronounced reddish hue 

away from deposits. Locally, also, oxidized deposits 

are closely associated with hematitic colors that range 

from moderate to dusky red (Sharp, 1955, p. 10).

Two general color zones in the district can be drawn 

on either side of an irregular boundary that extends 

from the outcrop north of Wingate northeastward 

through the northwestern part of T. 16 N., E. 15 W. 

This boundary roughly follows the east flank of the 

fracture zone that trends through the Church Eock 

area. Westward from this boundary the sandstone units 

in the Westwater Canyon and Brushy Basin are light 

gray for several miles and then grade to light brown, 

and, in the southern part of T. 16 N., R. 17 W., are 

mostly light gray. East of the boundary the sandstone 

units in the Westwater Canyon are predominantly a 

pale orange to reddish brown and are light brown or 

gray only locally. The sandstone units in the Brushy 

Basin in this part are generally a light brown and 

locally a light gray or a pale orange.

The light shades in the Church Rock area and in the 

area to the west of it generally are observed where the 

sandstone units are in contact with the overlying preDakota erosion surface (H. C. Granger, oral commun., 

1966), a relation that has been observed in many other 

places along the south and east margins of the San 

Juan Basin (Leopold, 1943; Schlee and Moench, 1961; 

Granger, 1961). (Also see pp. 20,61,71.) The light-gray 

colors probably have resulted largely from alteration of 

the feldspar minerals to kaolin and partly from 

removal of pigmenting colors by weathering during 

the interval following deposition of the Morrison 

Formation and prior to deposition of the Dakota 

Sandstone (Leopold, 1943; Schlee and Moench, 1961; 

Granger, 1961).

Except for the Black Jack 2 deposit in the eastern 

part of the district, nearly all the deposits in the 

Morrison occur in the western light-gray to lightbrown color zone.

SHIPROCK DISTRICT

Almost 40 deposits or groups of deposits are listed 

in the Morrison Formation in the Shiprock district 

(pi. 1). Most of them are clustered in a 10-mile str?p 

along the outcrop near the State line west of Shiprock. The most productive ones are concentrated in the 

southern part of the area between Horse Mosa on the 

south and Oak Creek (also called Oak Spring Wash or 

Oak Spring Canyon) on the north, where they have 

been collectively referred to as the Eastside mines. 

(See Stokes, 1951; Strobell, 1956; and O'Sullivan ard 

Beikman, 1963, sheet 2.) All the deposits occur in the 

Salt Wash Member and, unlike the other deposits in 

the Morrison in New Mexico, are high in vanadium 

content.

The total yield from the district has been roughly 

28,000-30,000 tons or ore, which had an average U: V 

ratio of 1:7 and a range among mining properties of 

3:2 to 1:13. The ores from three properties averaged 

less than 1 percent V2O5 , but these are represented by 

only 50 tons of material, which averaged 0.13 percent 

U3O8 . About 5,000 tons of ore shipped from 13 properties averaged about 9 percent lime, but had a range 

of from 1.5 to 21 percent lime. A shipment of 5 tons of 

material from one property contained 21 percent lime; 

this property was the only one on record whose o^*e 

had a total lime content exceeding 15 percent.

STRATIGRAPHY

The Salt Wash Member in the Shiprock district consists of very fine to medium-grained sandstone aid 

about 20-30 percent interbedded sandy and silty claystone (Strobell, 1956). The Salt Wash is 220 fe^t 

thick at Oak Creek, from where it thins and grades out 

southward into the Eecapture Member near Toadlena, 

thins westward into northeastern Arizona, and thins 

northward into southeastern Utah and southwestern 

Colorado where it is locally absent about 10-15 miles 

north of Four Corners (L. C. Craig, written commur -, 

1961). These data indicate the Salt Wash between 

Shiprock and some point west of Oak Creek composes 

a relatively thick elongate mass that trends eastward. 

This view is supported by the eastward trends of the 

resultant dip directions of the cross laminae in tl 3 

western part of the district (Craig and others, 1955, 

fig. 26). Apparently the Salt Wash between Shiprock 

and some point in Arizona west of Oak Creek represents a relatively thick segment that was deposited in 

a local downwarp between the south depositional margin of the member and a local upwarp that formei 

about the same time north of the Four Corners area.
82 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

North adit

Middle adits

Location of detailed section CLocation of detailed section

Roof

LBr

Channel sample 

^_ ^239600

LBr

-10-

P LBr

P 

Bl

Floor

- 5 -

0

Detailed sections C and B 

(Looking northwest)

FEET

V

FEET^.

50 -i

A'

 ____ C'aystone

Claystone

Sandstone

See detailed section B

50

I

100 150 FEET

_I

7\\ N

\ \ \

fo^fr. \

'°^%^>, V

s°°°0m\

°°z°°vi^\

0° r~~\^^^ \

v ^3° c^d

\° °°x,0 0\ \ V \ O° u \

\^J> \° \

\ 1

\ I

\ I

M x 1

LBr<£;

B[

. LBr\ -

.Roof.

p /Channel sample 

^.. 239601 '.P

P

ii-BI

Bl

Floor

y

-1O-

- 5 -

r>

Roof

Channel sample

239602, P LBr

V-----'-^?poir

Bkc? ""(5"^~~^"Sample

Px^: :::<^ 239607

B^: -;-:^"

" "BI

___ LBr

Floor

Detailed sections D and £"

(Looking east)

0 5 10 FEET

1 1 1

APPROXIMATE SCALE OF DETAILED SECTIONS

SCALE OF MAP AND SECTION A-A'

FIGUBE 12. Foutz 3 mine, Gallup district, New Mexico. Geology by L. S. Hilpert and A. F. Corey, Jr., 1955. Control by Brunton

and tape. See text (p. 80) for analyses of samples.
PENECONCORDANT DEPOSITS IN SANDSTONE 83

STBUCTUBE

The Shiprock district is on the northwest flank of 

the San Juan Basin where the beds dip eastward along 

the north end of the Defiance monocline, flatten east of 

the monocline on a structural terrace, and then plunge 

downward under the San Juan Basin along the northeastward-trending Hogback monocline. (See O'Sullivan and Beikman, 1963, sheet 2; this report, fig. 3.) 

From the outcrop along the Defiance monocline, the 

Morrison Formation extends eastward under younger 

formations. It is roughly 1,000-3,000 feet below the 

surface between the Defiance and Hogback monoclines, 

and southeast of the Hogback monocline is about 5,000 

feet or more below the surface. Faults are uncommon 

and only a few high-angle faults of small displacement 

occur locally. Subsidiary structural features are principally domes and anticlines within the structural terEXPLANATION

MAP

Strike and dip of joint Strike of vertical joint

Outline of mine workings 

Dashed where uncertain. Hachures at top and on side of near vertical face

Pillar Backfill

SECTIONS 

SECTION A-A' DETAILED SECTIONS

Contact between sandstone 

and claystone

Principal joint,

somewhat generalized

Dashed where inferred

Outer limit of purple 

hematitic halo

Ore zone 

Dashed where projected

Joint (section B)

Mineralized zone containing 

>0.1 percent eU (section B)

Boundary of color zone 

Bl, bleached; Gy, gray; LBr, 

light brown; P, pale purple; 

RBr, pale red brown

Clay galls

Outline of workings 

Dashed where projected I

Channel sample 

(sections C, D, and E)

FIGURE 12. Continued.

race, including the east flank of the Beclabito dome 

which is mostly in northeastern Arizona. Basaltic rocks 

in the form of sills, dikes, and plugs occur locally 

within the district.

MINERALOGY AND HABITS

Few specific ore mineral determinations have been 

recorded for the district. As the deposits occur largely 

at the outcrop and are oxidized they are conspicuous by 

the prevalence of yellow uranyl vanadates, generally 

reported as carnotite. These vanadates, however, probably are a mixtur3 of carnotite and tyuyamunite because of the fairly high content of calcium carbonate

FIGURE 13. Autoradiograph of ore specimen, Foutz 3 mine. 

White areas correlate with a canary-yellow mineral, probably 

a uranium vanadate (U), which probably also is in a finely 

disseminated material represented by the gray areas. Dark 

areas are mostly grains of quartz (Q), feldspar (F), and chert 

(C). Exposure 18 hours on Kodak medical X-ray no-screen 

film, by Mary H. Strobell. From polished section.
84 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

in the ore and host rock (Weeks and others, 1959, p. 

73). According to the classification of Botinelly and 

Weeks (1957), which is based on the U: V ratio in the 

ore and the degree of oxidation, hewettite should also 

be abundant, and vanadium clay (vanadium chlorite or 

vanadium hydromica) should be present. Associated 

gangue minerals are largely finely disseminated calcite, gypsum, and ferric oxide. The unoxidized or lowvalent ore minerals to be expected are coffmite, uraninite, and montroseite, and an associated gangue of 

calcite and some pyrite; the partly oxidized ore minerals to be expected are rauvite, corvusite, doloresite, 

hewettite, and vanadium clay (Botinelly and Weeks, 

1957, p. 4, and pi. 1).

Most deposits in the district are small; only a few 

have yielded more than a thousand tons of ore. The 

deposits consist of sandstone impregnated with ore 

minerals and some fossil plant material. High-grade 

replacements of fossil plants are uncommon, and fossil 

logs are scarce and generally small, and rarely attain a 

diameter of as much as a foot.

The deposits form blanketlike layers that follow the 

bedding in general, but cross it locally at low angles. 

These mineralized layers are gray or greenish gray, 

but in places are colored by bright yellow uranyl vanadates. Individual layers pinch and swell markedly 

within short distances, but rolls are less common and 

less well formed than in the deposits in the Salt Wash 

in southwestern Colorado. The layers range in thickness 

from 0 to as much as 15 feet and in width and length 

from a few feet to several hundred feet. In places, 

deposits comprise one or more layers that are separated 

by barren sandstone and locally they merge laterally to 

form podlike masses. Most deposits tend to occur in 

clusters, which generally are a few thousand feet across.

The ore bodies are the rather vaguely defined higher 

grade parts of the mineralized masses, except for a 

small number of isolated ore bodies. Within the clusters of deposits many of the ore bodies are connected by 

thin or weakly mineralized layers. The ore bodies 

range in thickness from about a foot to 5 feet or more 

and probably average about 3 feet, and they range in 

width from several feet to a few hundred feet.

The deposits occur where the sandstone and encompassed mudstone is gray; away from deposits the sandstone and mudstone are a general reddish color.

STBUCTUBAL RELATIONS OF THE DEPOSITS

Deposits in the district show only an indirect relation to Late Jurassic deformation and no apparent 

relation to later periods of deformation or to igneous 

rocks in the district. These relations will be reviewed, 

however, for the bearing they have on deposits elsewhere in the Morrison, as well as in the Shiprock 

district.

As indicated above, the deposits occur in a relatively 

thick part of the Salt Wash Member where the sedimentary structures and thickness data indicate that it 

occupies an eastward-trending structural depression. 

Because this depression formed in Late Jurassic time, 

the deposits contained in the host rocks are indirectly 

related to the deformation of Late Jurassic age, similar 

to the deposits in the Jackpile sandstone in the Laguna 

district.

The oldest recognizable post-Jurassic structural features in the district are the Defiance and Hogback 

monoclines, which probably formed about the same 

time as the uplifts marginal to the San Juan Basin, 

which are considered to be Late Cretaceous or early 

Paleocene in age (Kelley, 1955, p. 84). The deposits 

show no obvious relations to these monoclines and 

could possibly predate them.

Intrusive igneous rocks in the district and in adjacent parts of northeastern Arizona are of two ages. The 

dioritic intrusives are probably early to middle Tertiary but are possibly as old as Late Cretaceous (see p. 

31); the basaltic intrusives are Pliocene or Quaternary in age. The deposits show no relation to any of 

these rocks and are probably older, but dating is uncertain.

The basaltic igneous rocks intrude the Chuska Sandstone, south of the Shiprock district. The Chuska Sandstone rests on the beveled edge of Upper Cretaceous 

rocks (O'Sullivan and Beikman, 1963) and is generally considered to be late Tertiary in age through 

correlation of the underlying erosion surface with a 

similar surface under the Pliocene Bidahochi Formation (Hack, 1942). Because the basaltic rocks intrude 

the Chuska, they are considered to be Pliocene or 

younger in age. Masters (1955, p. 115) indicated that a 

basaltic dike in the east Carrizo area intersects uranium deposits and that the ore is prebasalt, but he gave 

no details.

CHTTSKA DISTRICT

About 18 deposits or groups of deposits are listed 

in the Morrison Formation in the Chuska district (pi. 

1). Most of them are clustered along the outcrop west 

of Sanostee in a relatively small area along Pena 

Blanca Creek, generally referred to as the Sanostee 

Wash area, where they are about equally distributed in 

the Salt Wash and Recapture Members (fig. 14). 

Most of the deposits have yielded some ore, but the 

total district yield of about 26,500 tons has come 

largely from the Enos Johnson 3 deposit in the upper 

part of the Recapture Member. The ores from the 

various mines range in U: V ratio from 1: 3 to 5:1 and
Upper Jurassic 

' Morrison Formation
86 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

average 2:1, similar to the ores in the Gallup, Ambrosia 

Lake, and Laguna districts. During the 1952-58 period, 

8,700 tons of ore yielded from 13 mining properties 

averaged 4.3 percent lime and among the individual 

properties ranged from 0.8 to 30.6 percent lime. The 

ores from four properties averaged more than 10 percent lime, but these ores represent only about 250 

tons of material. The high lime values probably represent ores largely from calcified fossil logs.

STRATIGRAPHJ

The Sanostee Wash area is near the south margin of 

the Salt Wash Member. At Sanostee Wash the Salt 

Wash is about 50 feet thick; northward it thickens to 

about 200 feet at the outcrop west of Shiprock. SouthWard it interfingers with and pinches out beneath the 

Recapture Member about 15 miles south of Sanostee. 

Cross-laminae studies in the upper part at Sanostee 

Wash (on north slope of Pena Blanca Creek, in fig. 14) 

and in the lower part at Horse Mesa, about 20 miles 

to the north, indicate a resultant dip direction of S. 

75°-85° E. (Craig and others, 1955, fig. 26). Uranium 

deposits in the Salt Wash Member occur in a gray 

sandstone, generally less than 30 feet thick, in the 

upper part of the member along a 3-mile strip of outcrop from the Carl Yazzie 1 northward to the John Joe 

1 (fig. 14).

I Sanostee Wash is at the north end of the conglomeratic facies and near the northeast end of the thick 

part of the Recapture fan, which centers in northeastern Arizona (Craig and others, 1955, fig. 22). From 

Sanostee Wash, where the Recapture Member is about 

500 feet thick, the Recapture thins northward and 

grades into a sandstone-mudstone facies in the Shiprock district. Cross-laminae studies by L. C. Craig 

(written commun., 1961) indicate that the resultant 

dip directions are generally northeastward. The northwestward direction of stream flow shown in the Sanostee Wash (fig. 14) area may represent a local variation from the regional pattern. It is not known what 

specific sedimentary structures are represented.

Uranium deposits in the Recapture crop out between 

the prospect immediately east of the Carl Yazzie 1 and 

the H. B. Roy 2, about 5 miles to the northwest. The 

largest deposits are in a light-gray sandstone in the 

upper part of the member. The sandstone, which has a 

maximum thickness of about 60 feet, occurs in a gray 

zone about 10 to 170 feet below the top of the member. 

This zone thins northward and southward from the 

vicinity of the Enos Johnson 3 and interfingers at its 

margins with red sandstone units in the general vicinity of the Dennet Nezz and Oarl Yazzie mines (J. W. 

Blagbrough, written commun., 1959). The eastward

extent of the gray zone, back from the outcrop, is not 

known.

STRUCTURE

The Chuska district is on the east flank of the Defiance uplift and west flank of the San Juan Basin, 

where the beds are upturned along the Defiance monocline, a sinuous northward-trending structural feature 

(pi. 1 and fig. 3). (See Kelley, 1955, p. 64, figs. 2, 5, and 

10; O'Sullivan and Beikman, 1963, sheet 2.) At the outcrop west of Sanostee, the Morrison Formation and 

bounding formations dip about 5°-10° NE. Five to six 

miles east of the outcrop, on the crest of the Beautiful 

Mountain anticline, approximately at Sanostee and 

about 2 miles east of the axis of the Ber.utiful Mountain syncline, the base of the Morrison is about 1,500 

feet below the surface. Eastward from this locality, the 

beds dip into the San Juan Basin on the Hogback 

monocline (O'Sullivan and Beikman, 1963).

J. W. Blagbrough (written commun., 1959) reported 

two well-developed joint sets in the Sanostee area, 

both approximately normal to the regional dip and 

roughly normal to each other. He indicated that one 

set was parallel to the "northwest trend of the Defiance uplift [probably more specifically referring to the 

Defiance monocline] " and the other "essentially parallel 

to the regional dip [northeasterly]." (S°-e O'Sullivan 

and Beikman, 1963, sheet 2.) The parallel and normal 

relations of the joint sets to the monocline indicate 

that they probably were formed at the same time as the 

monocline. As discussed earlier under o^.her districts, 

the moiioclinal folds on the flanks of the uplifts are 

probably Late Cretaceous to Paleoeene in age, so the 

joint sets are likely the same age.

An older, Late Jurassic, trough apparently trends 

eastward through the main part of the district. The 

evidence for it is stratigraphic. The Recapture in the 

main part of the district is at the north end of the 

conglomeratic facies and near the northeast end of the 

Recapture fan, and though the data are rather sparse, 

they suggest that the beds of the Recapture occupy a 

local structural trough somewhat similar to the troughs 

in the Laguna and Shiprock districts. This is indicated by the greater thickness of the Morrison Formation, the high ratio of thickness of stream deposits to 

thickness of flood-plain deposits, and the eastward 

trend of the trough from northeastern Arizona where 

the Recapture is thickest (Craig and others, 1955, figs. 

22,24,30).

MINERALOGY AND FORM

Little is known about the specific mineralogy of the 

deposits. Carnotite has been reported as the most 

obvious mineral in most of the deposits, but tyuyamu-
PENECONCORDANT DEPOSITS IN SANDSTONE 87

nite is probably also abundant. Schroekingerite was 

reported by Droullard and Jones (1951) and uranophane by Gruner and Smith (1955, p. 36), but no 

low-valent ore minerals have been identified. According 

to the classification of Botinelly and Weeks (195T), the 

expected low-valent ore minerals having U: V ratios 

from 3:1 to 1: 5 principally would be coffinite, uraninite, and montroseite. These minerals might be expected 

in the unoxidized zone back from the outcrop and, 

intermediate between these suites, the partly oxidized 

ores would be expected to consist mostly of rauvite 

associated with some vanadium minerals such as corvusite and dolOresite. The principal gangue minerals 

consist of finely disseminated calcite. some gypsum, and 

a mixture of iron oxides.

Several deposits in the Salt Wash have yielded ore, 

perhaps totaling as much as 2,000 tons, but the tonnage is uncertain because of mixed production records 

and the uncertainty of location of the Enos Johnson 

and Enos Johnson 1 and 2 mines. The ores, however, apparently are similar to those in the Kecapture 

because the U:V ratio is the same as that of the ores 

that can be identified and is unlike that of the vanadiferous ores of the Shiprock district.

General habits of the deposits are largely taken from 

J. W. Blagbrough (written commun., 1959). Deposits 

in the Salt Wash Member are in the upper part 

where they occur as thin tabular bodies in sandstone. 

The bodies generally bound mudstone beds, impregnate 

sandstone around concentrations or pockets of carbonized plant debris, fill fractures within carbonized logs, 

and are disseminated as halos in the surrounding 

sandstone. The deposits that bound the mudstone beds 

and that are associated with the plant debris range in 

thickness from a few inches to about 2 feet, and in 

length and width from a few feet to as much as 50 feet. 

They generally are smaller than the deposits in the 

Shiprock district. The mineralized logs are about 1-2 

feet in diameter and 3-4 feet long.

Deposits in the Kecapture Member occur in the lower 

part as fracture fillings in calcified logs and as impregnations of the enclosing sandstone; in the upper part 

they occur in sandstone as one or more crudely tabular 

layers along mudstone beds, as halos around mudstone 

galls and calcareous pods, and as halos around lenslike 

hematitic zones. The mineralized logs are from 2 to 3 

feet in diameter and range in length froom 5 to 15 

feet. Deposits in the upper part of the Recapture range 

in width from 150 to 200 feet, in length from 500 to 

600 feet, and in thickness from 1 to 20 feet. Orientation 

is not known. Only the higher grade parts are minable, and the configuration of the ore is rather ill defined as in the Shiprock district.

In general the deposits occur where the sandstore 

and mudstone are gray; no deposits are known wher^ 

the host rocks are red. Locally some deposits in tH 

upper part of the Recapture encompass pods of purple-red sandstone.

STRUCTURAL RELATIONS OF THE DEPOSITS

As in the Shiprock district, two periods of deformation may have influenced the emplacement of the uranium deposits Late Jurassic and Late Cretaceous to 

early Tertiary. Stratigraphic evidence indicates thr.t 

Late Jurassic deformation produced an eastward-trending troughlike structure through the main part of 

the district, The deformation may be assumed to have 

formed in Recapture time and to have died out prior 

to Dakota time because the thickness relations of the 

Salt Wash Member and the structure contours at the 

base of the Dakota Sandstone show no effect from it. 

The uranium deposits are indirectly related to this 

structure because they occur approximately on its axiswhere the Recapture Member, the principal host roc??-, 

is thickest. This relation is similar to that in the deposits in the Jackpile sandstone in the Laguna district 

and in the deposits in the Salt Wash Member in tH 

Shiprock district.

No evidence has been found, perhaps because of 

limited exposures, that indicates the deposits were influenced or controlled by the Late Cretaceous to early Te^- 

tiary deformation. Just west of the Sanostee area in Arizona, however, where rather extensive exposures of deposits in the Salt Wash Member occur, Masters (1955, 

p. 117) found no apparent relation in the position or 

trend of the deposits to the Lukachukai anticline ard 

adjacent syncline. These structural features, which are 

also referred to as the Lukachukai monocline aid 

Chuska syncline (Kelley, 1955) and the Toadlena anticline and Chuska syncline (O'Sullivan and Beikman, 

1963), are similar structurally to the Defiance monocline and probably formed during the same period of 

deformation. The deposits in the Chuska district apparently, therefore, where emplaced during or after Late 

Jurassic deformation and prior to or during Late 

Cretaceous to early Tertiary deformation.

OTHER DISTRICTS OR AREAS

Aside from the districts described, few deposits have 

been found in the Morrison Formation. Of about two 

dozen that are recorded, most of them are clustered 

in west-central Sandoval County on the southeast margin of the San Juan Basin, and the others are scattered 

in south-central Rio Arriba County near the south 

margin of the Chama Basin.

In Sandoval County, the deposits occur in two clu^- 

ters. The larger one, in T. 15 N., Rs. 1 E. and 1 W.,
88 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

consists of several scattered subsurface radioactive 

anomalies and several scattered radioactive zones at 

the outcrop. All are apparently in sandstone lenses in 

the Brushy Basin Members. Uranium minerals have not 

been identified in these deposits. The radioactive material at the surface is mostly concentrated around 

mudstone galls and lenses in fractured and limonitestained sandstone. The smaller cluster, in the southeastern part of T. 17 K, Es. 1 E. and 1 W., consists 

of several small deposits at the outcrop and in the 

subsurface. Most of them are in the Westwater Canyon 

Member and one is in an 18-foot-thick sandstone unit 

in the Brushy Basin Member. The latter deposit contains yellow and green uranium minerals associated 

with limonite, jarosite, pyrite cubes, and carbon in an 

iron-stained sandstone (A. Mirsky, written commun., 

1953). The mineralogy of the other deposits is not 

known. Most of them are described as radioactive 

anomalies around mudstone galls and along mudstone 

seams. Several hundred tons of ore was mined from 

one deposit in the Westwater Canyon Member in the 

1957-64 period.

In Rio Arriba County, five deposits are listed (table 

4), of which two consist of scattered radioactive bones 

and bone fragments. The other three are occurences 

of yellow uranium minerals, probably carnotite or 

tyuyamunite, in a white sandstone unit at the top of 

the Morrison Formation. The minerals occur on joint 

surfaces and as spotty disseminations in sandstone at 

the outcrop and in prospect pits.

PENNSYLVANIAN, PERMIAN, AND TRIASSIC ROCKS

About three dozen uranium deposits occur in stratigraphic units that range in age from Pennsylvanian to 

Triassic. These units contain a high percentage of fluvial material that largely composes the characteristic 

red beds of the Southwest. These contain the red-bed 

copper deposits, as well as uranium deposits, which are 

similar except for variations in their respective metal 

contents. Most of the deposits occur in the Cutler and 

Abo Formations of Permian age, and a few are in the 

Chinle and Dockum Formations of Triassic age and 

in the Madera Limestone of Pennsylvanian age. Most 

of them (27) are clustered in south-central Rio Arriba 

County; the others are dispersed in Torrance (4), 

Valencia (3), Sandoval (2), Bernalillo (1), and Socorro (1) Counties (pi. 1).

Uranium ore shipments were made in 1954H55 from 

three properties in the Cutler Formation, Rio Arriba 

County. The total was less than 100 tons and averaged 

0.14 percent U3O8 and 0.13 percent V2O5 . Shipments 

from two of the properties averaged 8 percent and 17 

percent lime, and about 0.3 percent copper.

MINERALOGY AND HABITS

The mineralogy of these deposits is incompletely 

known, partly because little work has been done on 

them and partly because the uranium minerals are 

fine grained, sparse, and not readily identifiable in the 

field. Where noted, they have been reported as yellow 

and green oxides associated with the copper carbonates 

malachite and azurite and the copper sulfides chalcocite, bornite, and chalcopyrite. These deposits are uraniferous variants of red-bed copper deposits; some of 

them were worked for copper ores befo^ they were 

prospected for uranium. The primary urfjiium minerals, where present, probably are coffinite and uraninite, 

which are similar to the other nonvanadiferous ores in 

sandstone. For more detailed mineralogy of uraniferous copper deposits see Weeks, Coleman, and 

Thompson (1959).

Most of the deposits consist of tabular or lenticular 

zones of finely disseminated material in san dstone. They 

are roughly parallel to the bedding, range/ in thickness 

from thin layers or seams to as much as 20 feet, and 

in lateral dimensions from a few feet tc as much as 

200 feet in width and 2,000 feet in length. Most of them 

probably average about a foot in thickness and only 

a few feet in lateral dimensions. Nearly all are low 

grade; high-grade material occurs only in local spots, 

generally as concentrations around carbonaceous plant 

debris.

Most deposits are closely associated with plant 

debris, and a few occur as coatings or halos around 

coalified or silicified logs. A few occur as local concentrations along and in the margins of claystone seams 

and galls and in siltstone.

Nearly all the deposits occur in a l x ost rock of 

coarse-grained locally conglomeratic arkosic sandstone 

which is light gray and locally stained light brown. 

Barren sandstone generally is reddish or reddish purple. The sandstone units generally range in thickness 

from a foot or so to as much as 60 feet, and they display conspicuous fluvial-type crossbeds and local channel scours at their base.

STRATIGRAPHIC AND STRUCTURAL RELATIONS

The deposit in the Madera Limestone occurs in the 

upper arkosic limestone member (sec. 31, T. 23 N., R. 

1 E., Rio Arriba County). This member wedges out 

northward against Precambrian rocks and generally 

grades southward into thinner bedded elastics and 

marine limestone. The arkosic sandstone units are 

generally thin bedded and are representative of a continental environment near the south margin of the 

San Luis highland. (See p. 28.)
PENECONCORDANT DEPOSITS IN SANDSTONE

As indicated under the section on stratigraphy, the 

Cutler Formation is approximately equivalent to the 

Yeso and the underlying Abo Formation to the south. 

The principal source area for the Cutler was the San 

Luis highland to the north, and the principal sources 

for the Abo were the ancestral Zuni highland to the 

west, the Joyita highland to the south, and partly the 

San Luis highland to the north (McKee and others, 

1967). From north to south, the arkosic sandstone units 

generally become thinner and their grain size somewhat finer, but these relations are reversed in the proximity of the two southern highlands. The principal 

uranium deposits in both the Cutler and Abo are concentrated along the flanks of the respective highlands 

that contributed most of the coarser clastic debris. 

(See McKee and others 1967.)

The late Paleozoic uplifts became buried by Early 

Permian time and, during Late Permian and Early 

Triassic time, the Lower Permian and older rocks were 

deformed and beveled. About Middle Triassic time, 

after Moenkopi deposition, the San Juan element to 

the north and the highlands to the south and southeast were upwarped and contributed clastic sediments 

southward and northward. These sediments formed 

the segments of the Chinle and Dockum Formations 

that are represented in northwestern New Mexico. Of 

the principal sandstone units, the Shinarump Member, 

Sonsela Sandstone Bed, and Poleo Sandstone Lentil 

probably were derived from the southeastern and 

southern highlands (Cooley, 1959; Stewart and others, 

1959; Poole, 1961; McKee and others, 1959, p. 22) and 

the Agua Zarca Sandstone Member from the San Juan 

highlands to the north and probably also in part from 

the south (McKee and others, 1959, p. 22). It is possible that the Agua Zarca and Shinarump are a continuous unit in the subsurface in the southeastern part 

of the San Juan Basin area (McKee and others, 1959, 

p. 22 and section B-B'', pi. 4).

Deposits in the Shinarump Member are probably 

near its east margin; the ones in the top of the Agua 

Zarca and base of the Salitral Shale Tongue are near 

the Agua Zaroa source area, and those in the Poleo 

Sandstone Lentil are near the northern known limit 

of the unit and are remote from the southern source 

area.

Eelations of the deposits to local structural features 

are little know. The southeast margin of the mineralized zone in the Poleo Sandstone Lentil terminates 

against a northward-striking steeply dipping fracture 

(H. G. Brown 3d, and L. L. Werts, written commun., 

1954), but the relative ages of the fracture and the 

mineralization are not known.

CRETACEOUS ROCKS

Several dozen uranium deposits or clusters of deposits are listed in stratigraphic units of Cretaceous 

age. These units were formed largely under marine, 

environment, and the deposits contained in them are 

almost entirely in rocks formed under near-shore or 

marginal continental conditions. The deposits are 

widely distributed throughout the area and in many 

places are closely associated with or make up parts of 

similar deposits in carbonaceous shale and lignitic shaJe 

or coal. Although the deposits in sandstone and in 

shale and coal are similar and in some places can be 

separated only arbitrarily, they are treated separately 

because of some differences in their ores and in th°s 

character of their host rocks.

The stratigraphic host unit and number of deposits 

in sandstone, by counties, are as follow (see table 4 

and pi. 1) :

Stratigraphic unit Number 

of deposits

County

Ojo Alamo Sandstone.

Fruitland Formation __________

Mesaverde Group:

Cliff House Sandstone- ______

Menef ee Formation _________

Point Lookout Sandstone. 

Point LookoutC?) Sandstone 1 . 

Gallup Sandstone.__________

Mesaverde Group undivided.

Mancos(?) Shale.______. 

Dakota Sandstone_______._.

1

1

1

1

2

1

10

1

1

3

1

1

11

1

2

Sandoval. 

San Juan. 

Do.

Sandoval.

San Juan.

McKinley.

Catron.

San Juan.

Socorro

Catron.

Sandoval.

Socorro.

McKinley.

San Juan.

Sandoval.

1 Possibly in part the Crevasse Canyon Formation.

2 One deposit, the Church Rock, is partly in the Morrison Formation.

Most of the deposits and all the productive one^1 , 

except one, occur in the Dakota Sandstone. Of 14 thp,t 

are listed, 9 yielded a total during the 1952-64 period 

of about 110,000 tons of ore that ranged from 0.12 

to 0.30 percent U3O8 and averaged about 0.22 percert 

U3O8 . More than 90 percent of this ore was mined from 

the Church Rock and Diamond 2 mines. About 43,5CO 

tons of this material, which was representative of seven 

properties, averaged 0.11 percent V2O5 . The U: V ratio 

averaged 3:1 and ranged from 4:1 to 1:1 among properties. The lime content from five properties for a total 

of about 40,000 tons of ore ranged from 0.5 to 1.8 percent and averaged about 0.5 percent.

The Midnight 2 (sec 12, T. 2 N., R. 11 W., Catrcn 

County) is the only productive deposit in Cretaceous 

rocks, other than the deposits in the Dakota Sandstone. 

It occurs in the Point Lookout (?) Sandstone or possibly in the Crevasse Canyon Formation. It yielded a
90 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

few hundred tons of low-grade ore in 1957 that had a 

IT: V ratio of 1: 2 and a lime content of about 2.5 percent. The Jack Boyd mine (sec. 3, T. 30 K, K. 15 W., 

San Juan County) in the Fruitland Formation reportedly yielded a small tonnage of ore-grade material, but is not listed in the official records as a producer.

MINERALOGY AND HABITS

Few data are available on the mineralogy of uranium deposits in rocks of Cretaceous age. The secondary uranium minerals carnotite, tyuyamunite, and 

metatyuyamunite have been reported in many of the 

deposits and generally described as impregnations and 

as coatings along joint faces and bedding surfaces in 

close association with limonite, jarosite, calcite, and 

locally gypsum. Meta-autunite and a variety of uranophane were identified in the "Desanti [Becenti]" deposit by Gruner, Gardiner, and Smith (1954, p. 39), 

but they gave no details. These, however, may have 

been the yellow uranium minerals observed in the deposit by the writer as disseminations in sandstone and 

as coatings on joint and bedding surfaces.

In the Diamond 2, carnotite was reported as the 

principal ore mineral in the workings above the 200 

level and pitchblende the principal ore mineral in two 

ore bodies that probably occurred along the 300 level 

(Gabelman, 1956a, p. 306). The principal black ore 

mineral in the deeper levels probably also was pitchblende, but could have been coffinite or a mixture of 

the two minerals.

In about half the deposits listed, the close association of the uranium minerals or radioactive material 

with carbonaceous material is noted. Where uranium 

minerals were observed they generally were intimately 

mixed with plant debris or occurred immediately above 

or below a carbonaceous bed. A few minerals consist 

of radioactive material associated with limonite, and 

a few occur at the contact of sandstone with clay or 

shale. The Jack Boyd deposit occurs in a tuffaceous 

sandstone unit that overlies a carbonaceous claystone.

In rocks of Cretaceous age the deposits consist of 

tabular masses that range from thin seams a few feet 

in width and length to crudely tabular masses as much 

as 2,500 feet in length and at least 1,000 feet in width. 

The larger deposits range from a few inches to as 

much as 25 feet in thickness, but generally average a 

few feet. Koll surfaces are less common, and the deposits are more blanketlike than the ones in Jurassic 

sandstone. This may stem partly from the close association of the uranium minerals with the carbonaceous 

debris, which is generally distributed in crude bedlike 

zones within the sandstone units, and partly from the 

tendency of the uranium minerals to accumulate on

relatively impervious claystone or shale units. Ore 

bodies, which generally compose the high-grade parts 

of deposits, range from small masses that comprise only 

a few tons of material to masses that include as much 

as or more than 50,000 tons of material. They range in 

thickness from a foot or so to 25 feet, but most of them 

are only a few feet thick and comprise orly a few hundred tons of material.

STRATIGRAPHIC AND STRUCTURAL RELATIONS

Nearly all the deposits occur near or at the base of 

sandstone units, and most of them at thQ, base of formational units. In the Dakota Sandstone most are in 

sandstone lenses that occupy channel scours at the 

base of the formation. These lenses range in thickness 

from 20 to 50 feet at the center and in width from 300 

to 800 feet; they consist mostly of fine- to mediumgrained sandstone and contain crossbeds that dip from 

8° to 25° (Mirsky, 1953). Locally these lenses are conglomeratic (Gabelman, 1956a, p. 316).

Trends of the lenses generally have not been determined, but the lenses apparently are clustered along 

the outcrop on the south flank of the San Juan Basin 

where Mirsky (1953, p. 8-9, 10-11) mapped about 30 

and noted their concentration in the area and their 

general absence elsewhere. Within the lenses the uranium deposits generally are closely associated with 

the distribution of carbonaceous material and, in at 

least two, the deposits underlie lenses of carbonaceous 

shale.

The principal ore bodies of the Diamond 2 mine 

(fig. 15) are apparently in one or more sandstone 

lenses (Mirsky, 1953; Gabelman, 1956a). Although the 

geology of the mine is incompletely known, it is reviewed for the stratigraphic and structural relations 

that bear on the ore controls and age relations of the 

uranium deposits in the Dakota Sandstone. The geology is abstracted and interpreted mostly from Gabelman (1956a) for the upper workings adjacent to the 

main incline, and partly from a later report by Chico 

(1959).

In the upper workings along the main incline, 

Gabelman (1956a) showed the ore bodies in a crossbedded sandstone at the base of the Dakota where it 

occupied a channel scour in the underlying Westwater 

Canyon Member of the Morrison Formation. He also 

showed the ore bodies as near the south margin of the 

host sandstone and under an overlying carbonaceous 

shale near its southward pinchout into thin-bedded 

sandstone. The dip direction of the crossbeds in the 

host sandstone has a southward trend (Mirsky, 1953, p. 

19). Gabelman showed that the ore bodies were controlled by shallow folds and to some extent by shallow
PENECONCORDANT DEPOSITS IN SANDSTONE 91

S\""/ Pincnou* of 

> ^ / channel-type N

NAOMI BECENTI LEASE

Outcrop of Dakota Sandstone

'AL-- Pinchout of channel-type 

t>. sandstone

EXPLANATION

Axis of anticline 

Showing plunge

Axis of syncline Near pmchout of chann

Showing plunge

¥;*^iM

Main incline 

(average inclination 28°30')

Mapped on 500 le 

Near pinchout of channel-type

Pinchout of channel-typ 

sandstone

Flowage structure 

Showing direction of flowage. Length exaggerated

Contact 4 ft above sill of specified level (300 level) 

between medium- to coarse-grained channel-type 

sandstone (Kdc) and fine-grained sandstone and 

carbonaceous shale (Kdf) of Dakota Sandstone

Contact 4 ft above sill of specified level (300 level) 

between Westwater Canyon Member of Morrison 

Formation (Jmw) and medium- to coarse-grained 

channel type sandstone (Kdc) or fine-grained 

sandstone and carbonaceous shale (Kdf) of 

Dakota Sandstone

Outline of mine workings 

Pattern indicates pillar

Elevation, in feet, at sill of entry or level 

Datum is approximate sea level 0

FIGTJKE 15. Diamond 2 mine. Shows local tectonic folds and flowage structures and stratigraphic relations of principal 

ore bodies to the host sandstone. Geology abstracted and modified from Gabelman (1956b) and Chico (1959). Base 

and mine map from Four Corners Uranium Corp., January 1959. Publication by permission of Four Corners Oil and 

Minerals Co.

329-381 O 69-
92 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

cross folds, the axes of which trended southwestward 

and northwestward, respectively, parallel to the dip and 

strike of the beds. He also indicated that the principal joints trended eastward and N. 10° W., and that a 

minor set trended northeastward, and stated that the 

prominent joints controlled the ore by acting as barriers. Presumably the structural control referred to 

carnotite bodies, as the only mention of low-valent 

uranium minerals in the mine is in the statement, 

"* * * two ore bodies recently discovered below the oxidized zone * * * are composed entirely of primary 

pitchblende ore." (Gabelman, 1956a, p. 306). These 

bodies were not included in his reference to the structural control by the folds and joints.

Later work by Chico (1959) in the deeper levels of 

the mine also showed that the principal ore bodies were 

in the basal sandstone and that the sandstone pinched 

laterally away from the margins of the bodies and 

pinched downward below the south ore body. His level 

maps show that the host sandstone is 10 feet or more 

thick in the central part of the south ore body, pinches 

out near the southeast limit of the body on the 425 level, 

and is at most only a few feet thick near the northwest limit of the body on the 450 level. On the 500 

level the sandstone has a maximum thickness of about 

7-8 feet and wedges out along the level near the main 

incline and about 150 feet north of it.

The host sandstone is missing along about 600 feet 

of the 500 level between the south and north ore 

bodies, but also likely occurs on the level under the 

north ore body. From a pinchout about 300 feet southeast of the body, it thickens northwestward to about 

12 feet at the south margin. About 50 feet north of 

the body, it has a thickness of only a few feet; at this 

point it seems to be pinching northward. The exposures under the north ore body could represent a segment of the same channel sandstone that contains the 

south body or possibly a segment of the channel 

sandstone that crops out at the Becenti deposit about 

half a mile to the northwest (Mirsky, 1953, fig. 3 p. 9). 

The north ore body apparently was controlled by a 

channel sandstone similar to one that controlled thesouth ore body; whether the sandstone pinches out below the 500 level, as it does along the 425 level, is not 

known. In addition to the folds described by Gabelman 

in the shallow workings, Chico described flowage 

structures in the deeper workings that may be useful 

in dating the emplacement of the ore.

Chico's description of the flowage structures indicates that they have a variety of shapes. Their direction of flowage is southwestward, parallel to the structural dip of the beds (fig. 15), but their internal structure is incompletely known and their ra age in size is 

uncertain. They probably are, however, as much as 

several feet thick and several tens of feet wide and 

long; they are bounded by undisturbed 1 ?/ds and show 

crumpling and folding back of the more disturbed 

beds over or around the nose of some folds. They are 

probably similar to the folds referred to as diagenetic 

by Gabelman (1956a, p. 306).

Age relations of the black ore to those structures and 

to later fractures indicate that the ore was emplaced 

after flowage and prior to fracturing. Pockets of coalified plant debris that were distorted by flowage of 

the sandstone are intersected by fractures. The coalified material is mineralized by black ore minerals, but 

the fact that crosscutting fractures are barren indicates that the mineralization was prefecture (Chico, 

1959, p. 63, fig. 22).

Age of the flowage structures is probaHy Cretaceous 

and about the same as or slightly younger than the 

deposition of the host rocks. The flowage took place 

prior to compaction and probably during initial uplift, because the direction of flowage is parallel to the 

dip of the Nutria monocline. The fractures formed 

after compaction, possibly about the time the initial 

fractures formed in the Ambrosia Lake district during the development of the McCartys syncline. If so, 

the black ore in the Diamond 2 was emplaced during 

Cretacous or Paleocene time, probably shortly after 

the initial uplift of the beds.

Relations of the other deposits in the Dakota Sandstone to tectonic structures are not clear. The oxidized 

minerals have a tendency to occur along fractures and 

under small folds and crenulations, but the relations 

of any low-valent or primary minerals is uncertain 

since none have been recognized. The association of 

the Dakota ore body in the Church Rock mine with 

the northeastward-trending fracture system suggests 

that the ore here is postfracture and perhaps redistributed, similar to the postfault unoxidized ore of the 

Ambrosia Lake district.

Little information is available on the stratigraphic 

and structural relations of the deposits that occur in 

formations above the Dakota Sandstone other than 

their tendency to occur at the base of sandstone units 

above a rather impermeable clay or sh^le bed and to 

generally show an intimate relation to carbonaceous 

debris or carbonaceous shale. Somewhat exceptional is 

the McPhaul deposit, in Catron County; it occurs in 

a small shallow syncline that may hav<s partly controlled its emplacement.
PENECONCORDANT DEPOSITS IN SANDSTONE 93

TERTIARY AND QUATERNARY ROCKS

About two dozen deposits or clusters of deposits are 

listed in stratigraphic units of Tertiary and Quaternary ages, all of which were deposited in a continental environment. From oldest to youngest the units 

and the number of deposits which they contain are a 

follows: Nacimiento, 1; San Jose, 4; Galisteo, 1; Baca, 

10; and Santa Fe, 10. The deposits principally occur 

hi the northern part of Santa Fe County and in western Socorro County; others are scattered in Kio Arriba, Catron, and Sandoval Counties (pi. 1). A small 

tonnage of moderately low grade ore was shipped 

from the Red Basin 1 deposit in 1954; this ore had a 

U: V ratio of 1:1 and a content of about 15 percent 

lime. A small amount was also shipped from the Hook 

Ranch (Jaralosa) mine in 1959-60. The Reel Basin 1 

is in the Baoa Formation, probably also the host formation of the Hook Ranch mine deposit.

MINERALOGY AND HABITS

Information on the mineralogy of the deposits is 

meager. Except for those deposits in the Santa Fe 

Group, most have been reported simply as radioactive 

or uraniferous zones, closely associated with carbonaceous material or limonite. Yellow-green uranium 

minerals and meta-autunite( ?) occur in deposits in 

the Baca Formation, and autunite occurs hi a deposit 

in the Galisteo Formation. In the Santa Fe Group, 

carnotite, schroekingerite, and meta-autunite coat fracture and bedding surfaces of sandstone, siltstone, and 

claystone and are generally concentrated where the 

sandstone contains clay galls and pockets and seams 

of coalified plant debris. Radioactive opal locally occupies fractures, and some of the higher grade deposits are within opal-cemented halos.

The deposits are generally surficial, small, and low 

grade. They range from seams or small pockets, an 

inch or so thick and a few feet wide and long, to 

crudely lenticular masses as much as several feet thick 

and 100 feet long. Exceptionally large ones are the 

Red Basin 1 (sec. 19, T. 2 N., R. 10 W.), in the Baca 

Formation, which extends along the outcrop for about 

half a mile and back from the.outcrop for several 

hundred feet, and the We Hope 4 (sec. 4, T. 13 N., R. 

6 E.), in the Galisteo Formation* According to a private report, the We Hope 4 deposit is a few hundred 

feet long and wide and as much as 25 feet thick, and 

it is within a radioactive seleniferous zone that can be 

traced along the outcrop for about 1 mile.

STRATIGRAPHIC AND STRUCTURAL RELATIONS

Host rocks containing the deposits were laid down 

in four separate basins or depressions. The Nacimiento 

and San Jose Formations were deposited in the San

Juan Basin during its early development and were 

derived from debris shed from highlands to the east 

and north. (See p. 30.) Northward tilting and some 

folding, faulting, and intrusion by lamprophyric dikes, 

sills, and other igneous bodies followed the deposition 

of the San Jose. These tectonic events probably were 

intermittent from early Eocene until Quaternary time 

(Dane, 1946, 1948), but they had little apparent infuence on the uranium deposits in the San Jose and 

Nacimiento Formations. Mineralogic and surficial relations of the deposits indicate that they probably formed 

as shallow accumulations from ground water in and 

around carbonaceous debris.

The Galisteo Formation was deposited in a depression that resulted from late Eocene warping and was 

derived from debris shed principally from the Nacimiento uplift area to the northwest and the southern 

part of the Sangre de Cristo Mountains area to the north 

(Stearns, 1943). The Galisteo in the Cerrillos Hills, 

Ortiz, San Pedro, and South Mountains was intrud<xl 

during Oligocene time by stocks and laccoliths and in 

peripheral areas by dikes and sills. The intrusions were 

accompanied by some normal faulting. Differential subsidence and faulting in late Tertiary and Quaternary 

time formed the Rio Grande trough across the northwest flank of the Galisteo basin of deposition. Erosion, 

attendant to these events, left partly exposed remnants 

of the Galisteo through the deeper part of the basin, 

roughly in the area between Algodones on the west and 

Lamy on the east, a distance of about 35 miles (Stearns, 

1953, pi. 1). In spite of the long sequence of tectonic 

events, the uranium deposit in the Galisteo and the 

radioactive zone with which it is associated show no 

apparent relation to faults, folds, igneous rocks, or 

other tectonic structural features. The deposit may be 

a neai'-surface accumulation of uraniferous material 

that precipitated from downdip-migrating meteoric 

water. This possibility is suggested by the dip of the 

beds, about 30° E., the solubility of autunite, and the 

concentration of the higher grade part of the deposit 

roughly 50-200 feet below the outcrop and nearly parallel to the bedding.

The Baca Formation accumulated in a basin or 

several interconnected depressions that formed during 

late Late Cretaceous to early Eocene time in the area 

roughly outlined by Socorro and the eastern part of 

Catron Counties. The basin resulted from compressive 

forces that caused warping and some reverse faulting 

along north-trending lines in the south-central part of 

the area. Extensive regional erosion followed the warping and furnished the material found in the Baca; some 

of it was derived from the south (Wilpolt and Wanek, 

1951) and some from the Lucero uplift area to the nor^h
94 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

(Kelley and Wood, 1946). Deposition of the Boca was 

succeeded by volcanic and intermittent sedimentary 

activity that produced the Datil Formation of probably 

late Tertiary, possibly Miocene, age. The Datil is conformable on the Baca Formation in the central part of 

the area (G. O. Bachman, E. H. Baltz, and R. L. 

Griggs, written commnn., 1957), but overlaps the 

beveled edge of older rocks to the east (Wilpolt and 

Wanek, 1951). It is overlain unconformably by the 

Santa Fe Group and is more complexly faulted than 

the Santa Fe (Wilpolt and others, 1946).

The following stratigraphic and structural relations 

of the principal uranium deposits in the Baca are 

abstracted from G. O. Bachman, E. H. Baltz, and R. 

L. Griggs' (written commun., 1957) reconnaissance 

studies of the upper Alamosa Creek valley, Catron 

County.

In the general region of the deposits the beds dip 

about 3° SW. and locally are folded gently along fold 

axes that trend roughly parallel to the regional dip. 

Faults are uncommon, are of normal type, and have 

displacements of less than 100 feet (fig. 16).

Host rock of the principal deposits, the Red Basin 

1 and 2, is a lenticular sandstone unit that apparently 

fills an old stream channel cut into the Point Lookout ( ?) Sandstone (fig. 17). To the southwest this basal 

sandstone unit apparently wedges out between shale in 

the Point Lookout (?) and the overlying shale of the 

Baca Formation. To the northeast the basal unit thins 

rapidly and wedges out about 1,500 feet northeast of 

the southwestern pinchout.

The southwestern pinchout can be observed in a 

prospect cut, and its projection is based partly on drillhole data. The northeastern pinchout is based on exposures in, and projections from, two outliers of the basal 

sandstone unit.

Since deposition, the rocks have been tilted to the 

southwest so that the southwestern part of the channel, the part containing the deposits, is topographically lower than the northeastern part. Tilting must 

be post-Datil in age, because the Datil shows about 

the same regional dip as the older rocks. (See fig. 16.) 

Bachman, Baltz, and Griggs (written commun., 1957) 

believed that ground water carried uranium in solution into the basal sandstone of the Baca Formation 

and that the uranium was deposited where this aquifer wedges out between shale units.

Apparently the only tectonic features to which the 

deposits can be related are the synclinal folds that 

trend roughly parallel to the regional dip. These folds 

were noted in the Crevasse Canyon Formation and 

Point Lookout(?) Sandstone, but not in the overlying Baca Formation, so it is possible that they are

pre-Baca or Late Cretaceous to early Tertiary in age. 

If so, they may have partly controlled the development of the stream channel cut in the Point Lookout 

(?) Sandstone and the subsequent filling of that 

channel by the basal sandstone of the Baca. If the 

uranium deposits were emplaced after regional tilting, their age is certainly post-Baca and probably 

post-Datil and can range from Miocene to Recent.

The youngest of the Tertiary structure] depressions, 

the Rio Grande trough, probably orig; nated in late 

Miocene time and cut across earlier structures, such 

as the Galisteo and Baca basins. Its development attended periodic faulting, depression, and filling with 

clastic debris and some fine volcanic debris from marginal uplands more or less intermittently and from 

place to place until Recent time. As a result, the beds 

dip at various angles from place to place, but generally from the flanks toward the central part of the 

trough at moderately low angles. The fill in the basin 

also varies in thickness from place to place but probably in the central part averages several thousand 

feet. Because the fill is generally unconsolidated, it 

serves as a highly permeable aquifier that permits 

southward flow of ground water.

Known uranium deposits in the Santa Fe Group 

are nearly all concentrated in a small area between 

Espanola and Santa Fe within a stratigraphic interval of a few hundred feet. The beds am in the Tesuque Formation, of middle(?) Miocene to early Pliocene age, and were derived largely from Precambrian 

crystalline rocks to the east (Spiegel and Baldwin, 

1963, p. 39-40) and partly from volcanic debris from 

the Jemez volcanic center to the west and the San 

Juan volcanic center to the north (R. L. Cannon, R. L. 

Smith, and H. L. Cannon, written commun., 1955).

The deposits show no apparent relations to faults 

or folds and are surficial. They likely represent accumulations of radioactive material from the present 

cycle of circulating ground water. Thir possibility is 

suggested by the highly soluble uranium minerals; 

small size and low grade of the deposit?; the envelopment of some deposits by radioactive coal; the close 

association of the deposits with carbonaceous debris, 

claystone, and limonite; the high uranium content of 

the host rocks; and the young age of the deposits. The 

radioactive opela is related to the present cycle of 

weathering because it occurs as films and coatings on 

boulders and concretions at the surface, as a cement 

at the tops of beds of relatively fresh vitric ash, and 

as a cement in sands just beneath the aeh (R. L. Cannon, R. L. Smith, and H. L. Cannon, written commun., 1955).
PENECONCORDANT DEPOSITS IN TODILTO LIMESTONE 95

The high uranium content of the host rock is demonstrated by a suite of 10 samples collected between 

Abiquiu and Santa Fe (fig. 18). Uranium content of 

these samples ranged from 2 to 12 ppm (parts per 

million) and averaged >5 ppm. Eight of the samples 

were sandstone and two were siltstone. Although they 

were collected roughly parallel to the strike of the 

beds, they likely represent several hundred feet of 

stratigraphic section, including the part that contains 

the uranium deposits, because the coverage is about 40 

miles.

The high uranium content of the Tesuque Formation can most likely be attributed to the high uranium 

concentrations in the volcanic ash, as shown by the 

following five samples:

Sample Locality Description

Uranium 

content (ppm)

U eU»

2A 2 _..__ Center E^ sec. 33, 

T. 19 N., R. 9 E. 

(= 1 mile south of 

locality of sample 

252605, fig. 18).

2B 2_________-do__._.____.._.

22. .do.

239584___ NW^SE^ sec. 17, 

T. 20 N., R. 9 E.

239585 Center SWtf sec. 17, 

T. 20 N., R. 9 E. 

(=3,500 ft northeast of locality of 

sample 252603, 

fig. 18, and 1,700 

ft west of locality 

of sample 239584 

(see above).

Top 3 in. of 42- 18. 1 

in.-thick exposure of ash bed.

28 in. above base 10. 7

of ash bed described for

sample 2A. 

6 in. above base 5. 6

of ash bed described for

sample 2A. 

Channel across 4- (3 )

ft-thick white

tuff bed.

20

30

1 Analyst, C. G. Angelo.

2 Data from R. L. Cannon (oral commun., 1965). 

»No data.

These samples show a range in content of 5.6-30 

ppm U or eU and, although the elJ values may be 

high because of disequilibrium, the tuffs probably 

average more than the entire host rock.

The uranium deposits postdate the Tesuque Formation. Their surficial relations and envelopment within 

radioactive opal, which also coats surficial debris, indicate that they were probably formed in the present 

cycle of weathering.

PENECONCORDANT DEPOSITS IN TODILTO LIMESTONE 

AND ADJACENT FORMATIONS

About 100 deposits or clusters of deposits are listed 

in the Todilto Limestone, of Jurassic age, on plate 1. 

Deposits occur in other limestone units, but are uncommon ; nearly all of them are associated with faults and 

are classified as vein deposits. A few others are segments of deposits that are primarily in sandstone; tiny 

have been described previously. Most of the depos;ts 

in the Todilto Limestone are in the Ambrosia Lake 

and Laguna districts, McKinley and Valencia Counth-s. 

A few are scattered in the southern part of the Ghana 

Basin, Rio Arriba County, and in the Chuska district, 

San Juan County.

From 1950 to 1964, about 980,000 tons of ore was produced from 52 mines in the Todilto Limestone. This c^*e 

had an average grade of 0.22 percent U3O8 but ranged 

from 0.10 to 0.43 percent U3O8 among the mines. Prior 

to 1959, 445,000 tons of this ore averaged 0.14 percent 

V2O5 and had a U: V ratio of about 5: 2, similar to tli at 

of most of the deposits in sandstone. All but a few 

thousand tons was mined in the Ambrosia Lake District; 

the remainder came from three mines in the Laguna 

district and one mine in Kio Arriba County.

The ores ranged fro 25 to 98 percent lime and averaged 80 percent. Ores from only a few mines averag'Mi 

less than 50 percent CaGO3 ; these were mostly mixed 

ores that came from deposits that extended into the 

underlying Entrada Sandstone or overlying Summerville Formation, such as the Sandy, Zia, and Haystack 2.

STRATIGRAPHY

Kegional stratigraphy of the Todilto Limestone and 

its relations to the underlying Entrada Sandstone and 

overlying Summerville Formation were outlined previously (p. 18), but the local stratigraphy in the Ambrosia Lake and Laguna districts will be discussed in 

more detail to explain the relationships of the deposits.

In the Ambrosia Lake district only the limestone 

member crops out, but the gypsum-anhydrite memHr 

has been penetrated by drill holes about 8 miles 

north of the outcrop (J. C. Wright, written commun., 

1957). The limestone member, which contains all the 

deposits, ranges in thickness from about 5 to 30 feet 

and averages about 15 feet. It comprises three units 

which are referred to locally as the basal "platy," ir^- 

dial "crinkly," and the upper "massive" zones. T ? 

platy and crinkly zones are about equal in thickness 

and compose about half the total thickness of the member. They consist of fine-grained laminated and thinbedded limestone, which contains thin siltstone partings and locally seams of gypsum. Black fine-grain^xl 

films of carbon-rich material are conspicuous locally, 

especially along the partings in the crinkly unit. Bedding in the platy unit is undisturbed, but in the crinkly 

unit is intensely crenulated. The massive unit is more 

coarsely crystalline and indistinctly bedded limestor^, 

and it varies markedly in thickness from place to place.
96 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

108°00'

R. II W. 5 MILES R - 10 w -

FIGTTBE 16. Upper Alamosa Creek valley, Geology by R. L. Griggs, 1954; modified from G. O. Bachman, E. H. Baltz, and 

R. L. Griggs (written commun., 1958). Base compiled from planimetric maps of U.S. Department of Agriculture. Soil 

Conservation Service.
PENECONCORDANT DEPOSITS IN TODILTO LIMESTONE 97

EXPLANATION

ft

I

I

Pediment gravel

Datil Formation

Baca Formation

Sandstone, stltstone, and shale; some conglomerate

Point Lookout (?) Sandstone

Massive sandstone; minor amount of interbedded

shale and thin sandstone

Crevasse Canyon Formation

Contact 

Dashed where inferred

Normal fault

Dashed where inferred.

U, upthrown side; D, downthrown side

Strike and dip of beds

Syncline 

Showing direction of plunge

Uranium prospect

NOTE: All drainage is intermittent 

FIGTJBE 16. Continued.

In many places it contains limestone breccia cemented 

by calcite, and locally the top of the unit is a breed a 

with fragments of limestone embedded in sand derived 

from the overlying Summerville Formation. Lenr°,s 

of siltstone also occur in the massive unit and indies te 

the gradational relations of the Todilto with the overlying Summerville Formation.

Both the limestone and the gypsum-anhydrite members are exposed in the Laguna district. The limestone 

member is as much as 35 feet thick at the outcrop 

in the southern part of the district, but to the north, 

where it is overlain by the gypsum-anhydrite member, 

it is only about 10 feet thick. The limestone member 

consists of two units of about equal thickness, a lower 

bedded unit and an upper massive unit that are lithologically and structurally similar to the platy and 

massive units in the Ambrosia Lake district. The lower, 

or bedded unit, ranges in thickness from a few feet to 

as much as 35 feet and probably averages about 10 fe^t. 

The massive unit is discontinuous and highly varial^e 

in thickness from place to place, but is locally as nw.h 

as 15 feet thick.

Where the gypsum-anhydrite member is missing, 

the massive limestone unit and basal sandstone beis 

of the Summerville Formation in many places are intimately mixed, and thin layers of sandstone and siltstone are tightly folded. These relations suggest flowage after deposition but before consolidation of the 

sediments (R. H. Moench, written commun., 1962). 

Brecciation and mixing in the same stratigraphic zone 

in the Ambrosia Lake district is probably the result 

of similar flowage. The gypsum-anhydrite member 

crops out in the Laguna district where it ranges in 

thickness from 0 to 75 feet. This exposure is the south 

end of the thick part of the member (pi. 3), which 

extends northward along the east side of the San Juan 

Basin.

STRUCTURE

Structures that bear on the occurrence of the uranium 

deposits in the Ambrosia Lake and Laguna districts 

were formed during three periods of deformation: (1) 

Late Jurassic to Early Cretaceous, (2) Late Cretaceous 

to middle Tertiary, and (3) middle Tertiary to late 

Tertiary or Quaternary. Most of the uranium deposits 

in these districts occur in the Todilto Limestone, where 

they are mostly in, or closely associated with, intraformational folds that formed during the first period 

of deformation and, thus, are allied with the proDakota folds and pipelike structures. (See page 6£). 

Similar intraformational folds also occur in the Chuska 

district and in the southern part of the Chama Basin. 

They also probably formed during the first period of 

deformation and likewise contain uranium deposits.

PENECONCORDANT DEPOSITS IN TODILTO LIMESTONE

R. 7 E. R. 8 E. 106°00' R. 9 E.

99

R. 10 E.

 36° 15'

T. 23 N.

T. 22 N.

T. 21 N.

T. 20 N.

252601(SS-2)

252602(SS-3) 

252603(ST-6)

T. 19 N.

EXPLANATION

i 252601(SS-2)

Sample locality and number. (SS-2),host 

rock (SS, sandstone; ST, siltstone) and 

uranium content, in parts per million. 

Fluorimetric analyses by E. J. Fennelly

Outline of area containing uranium deposits and radioactive anomalies in 

the Santa Fe Group

T. 18 N.

 35°45'

T.17 N.

10 MILES

FIQTIEE 18. Sample localities and sample contents of uranium in Santa Fe Group, Rio Arriba and

Santa Fe Counties, N. Mex.
100 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

Rapaport, Hadfield, and Olson (1952) first described 

the intraf ormational folds and dated their development 

as shortly after deposition of the Todilto sediments. 

Gabelman (1956b) described some of them in detail and 

drew similar conclusions regarding- the age of their 

formation, and Hilpert and Moench (1960) described 

their association and probable contemporaneity with 

the larger pre-Dakota folds in the Ambrosia Lake and 

Laguna districts.

The intraformational folds occur in a great variety 

of shapes, ranging from open and closed anticlines to 

recumbent folds, chevron folds, and fan folds. They 

are mostly anticlinal and asymmetric, but some are 

synclinal, open, and symmetrical. Most of the folds are 

small, pronounced structural features that have amplitudes generally less than their breadths. The largest 

have a breadth of as much as 50 feet and an amplitude 

of about 25 feet and involve the entire thickness of the 

Todilto and basal part of the overlying Summerville 

Formation. The smallest are measured in inches or 

fractions of an inch and commonly bear a drag relation 

to larger folds. In length the folds range from a few 

feet to hundreds of feet. They mostly are somewhat 

sinuous and elongate, but some are rather tortuous in 

plan or are simply domal.

The folds generally tend to be concentrated or clustered, and in both the Ambrosia Lake and Laguna districts the fold axes in the clusters generally trend eastward or northward. Others show an almost random 

arrangement.

All the folds are fractured or jointed and some are 

faulted. The associated faults, however, are almost invariably intraformational and die out within the folds 

or within the Todilto Limestone and basal part of the 

Summerville Formation. Many faults are reverse type 

and closely follow the axial plane of tight or recumbent 

folds. All the related faults, however, show little displacement, seldom more than a foot or so and generally 

not more than a few inches.

Most joints are nearly vertical and comprise many 

sets. The principal set is longitudinal to the folds and 

probably formed with the folds or shortly after, similar 

to the intraformational faults. Other subsidiary joints 

make up an almost random pattern, although in some 

deposits in the Ambrosia Lake district a minor set is 

roughly normal to the fold axes. Many of the joints 

probably formed during later periods of deformation. 

The complexity of the fold and fracture patterns is 

illustrated by the structures in the Haystack, Gay 

Eagle, and Black Hawk deposits (Gabelman, 1956b, 

figs. 135-137).

In the Laguna district the intraformational folds are 

localized along the flanks and troughs of broad eastward- and northward-trending pre-Dakota synclines, 

and the dominant trends of the axes of the intraformational folds are likewise eastward and northward 

(Moench, 1963c, p. 159). (See fig. 9, this report.)

The Todilto Limestone in the Laguna district is also 

somewhat thicker in the synclines than on the crests 

of the adjoining folds. This fact suggests tl^.t the intraformational folds formed by flowage dovn the limbs 

of the pre-Dakota folds. This flowage apparently occurred under cover in post-Todilto time because the 

intraformational folds are not, truncated by bedding 

planes.

Similar relations are indicated in the Anbrosia Lake 

district. Where data are available, particularly where 

uranium deposits have been mined, the intri-formational 

folds also tend to trend eastward and northward and 

to make up clusters with similar trends (Gabelman, 

1956b, figs. 134-138; Hilpert and Moench, 1960, p. 460- 

461. fig. 18). The pre-Dakota folds in the overlying 

rocks likewise trend eastward; others migH also trend 

northward, as in the Laguna district, but riore detailed 

information is needed to determine this.

In the Chuska district small anticlinal intraformational folds occur along a 4-mile strip of outcrop west 

of Sanostee in the upper part of the Todilto. The largest 

folds have amplitudes of as much as 2 feef, a width of 

3 feet, and a length of 15 feet. Where cor^ntrated or 

most highly developed they are subparallel, but show 

no relation to Laramide structures (J. W. Blagbrough, 

D. A. Thieme, B. J. Archer, Jr., and R W. Lott, written 

commun., 1959).

In the south part of the Chama Basin, similar intraformational folds have been noted in the Todilto Limestone at the outcrop south and east, of Coyote. Some of 

these folds have amplitudes of as much as several feet 

and widths of as much as 25 or 30 feet, but their lengths 

and trends are not known.

Structural features that formed principally during 

the second period of deformation in the Ambrosia Lake 

district consist of the Chaco slope or homocline, west 

flank of the McCartys syncline, a set of fractures and 

folds that range in trend from northeast to north, and 

some domal and anticlinal structures. (See p. 61-62). In 

the Laguna district they consist of the east limb of the 

McCartys syncline, a north-trending faulted monocline, 

and a set of faults and fractures that wens intruded in 

many places by diabasic dikes and sills. (See p. 72).

MINERALOGY AND FORM

Mineralogy of the uranium deposits in the Todilto 

Limestone has been partly described by Rar>aport, Hadfield, and Olson, (1952, p. 9-12), Laverty and Gross 

(1956, p. 200), and Truesdell and Weeks (1960), and
PENE CONCORD ANT DEPOSITS IN TODILTO LIMESTONE 101

has been summarized by Granger (1963, p. 33-35) and 

by McLaughlin (1963, p. 140).

The deposits in the Todilto differ from the ones in 

sandstone principally in their relative sparseness of 

metallic sulfide minerals and in the occurrence of 

fluorite.

Unoxidized minerals that have been identified are 

uraninite, coffinite, paramontroseite, haggite, fluorite, 

pyrite, marcasite, and galena. Barite, specular hematite, vanadium clay, and recrystallized calcite are closely associated with these minerals and probably are also 

primary.

Ura.ninite is more abundant than coffinite and occurs 

as colloform coatings on grain boundaries, as veinlets 

in limestone, and as replacements of the limestone 

grains along bedding planes and along the walls of 

veinlets. Coffinite at least locally coats uraninite and 

fills shrinkage cracks in uraninite.

The formation of haggite, paramontroseite, and 

vanadium clay generally preceded that of uraninite. The 

haggite occurs as fine blades and fibers along grain 

boundaries and solution channels in limestone, and 

some as intergrowths with paramontroseite. The vanadium clay in some places forms irregular spherical

Fluorite has been observed in several deposits and 

likely is a constituent of most of them. It generally is 

purple and occurs as a fine-grained replacement of the 

limestone along bedding surfaces, as veinlets, and 

locally as irregular replacements of limestone that 

form masses as much as 6 inches in diameter. The 

fluorite generally is closely associated with and in places 

is replaced by uraninite.

Pyrite, marcasite, and galena are the only sulfide 

minerals identified in the deposits in the Todilto. Pyrite occurs as an early mineral which is generally corroded and replaced by later minerals but is most abundant as a late mineral which fills solution cavities and 

fractures and which replaces detrital grains. Marcasite 

has been identified only as a late mineral. Galena 

occurs as fine-grained cubes deposited with and after 

uraninite and coffinite and as a replacement of early 

pyrite and haggite.

Coarse-grained calcite occurs along bedding planes, 

fractures, and solution cavities as a replacement of 

limestone or as recrystallized limestone in and near 

the uranimum deposits. The coarse-grained calcite is 

both earlier and later than most other minerals.

Fine-grained hematite occurs in most of the deposits 

and generally is associated with the uraniferous zones. 

Specular hematite has been noted with vanadium clay. 

Hematite also occurs as pseudomorphs after pyrite and

as stains along fractures and bedding planes in cxidized zones.

Barite occurs in most deposits as a resinous yellow 

to clove-brown tabular mineral that lines solution 

cavities and forms veinlets or irregular globelike replacements of coarse-grained calcite or local disseminations along the bedding.

Most of the deposits in the Todilto occur at or n°-ar 

the surface and so have been subjected to oxidation 

which has led to the rather widespread occurrence of 

the conspicuous yellow and green secondary minerals 

tyuyamunite, metatyuyamunite, uranophane, and probably sklodowskite. Less common secondary minerals are 

carnotite, cuprosklodowskite, gummite, santafeite, liebigite, and various oxides of manganese and iron. Also, 

the dark-olive green fibrous vanadyl vanadate, grantsite, 

was identified in the F-33 mine (Weeks and others, 

1961) and probably occurs in other deposits in the 

Todilto.

Early field-examination reports generally mentioned 

carnotite as a constituent of most deposits and created 

the impression that the mineral was one of the more 

common ones. Most of the reported occurrences, however, were probably tyu.yamunite, which is more likely 

to form in limestone in which calcium is in excess of 

sodium. Tyuyamunite and carnotite are both canary 

yellow and difficult to distinguish in the field.

Uranium deposits in the Todilto are roughly tabular bodies having an irregular form similar to the 

forms of the deposits in sandstone. Most of them oc"<ur 

along the flanks of the folds and some along the fold 

axes roughly parallel to the bedding, but locally the 

deposits cut across the bedding. Many of them are E ear 

the base of the Todilto, but others are near the middle 

or top, and a few occupy the entire limestone interval. 

Many are not confined to the limestone, but extend a 

few inches and in some places several feet into the 

underlying Entrada Sandstone, and in many deposits 

as much as several feet into the overlying siltstone of 

ths Summerville Formation. A few deposits are mostly, 

or entirely, in the basal part of the Summerville or 

top of the Entrada Sandstone. Although these deposits 

have a relationship to bedding that is similar to that 

of deposits in other sandstones, they are dissimilar in 

their association with folds in the overlying or uncHrlying Todilto Limestone.

Dimensions of the deposits in the Todilto range from 

a few feet in width and length to several hundred feet 

in width and more than 1,000 feet in length, and in 

thickness from mere seems to as much as 20 feet. Tv^y 

probably average a few tens of feet in width, a hundred feet or so in length, and about 10 feet in thickness.
102 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

The largest deposits occur where the folds in the 

limestone are clustered and have a similar trend. Because of the clustering, the deposits associated with 

individual folds interconnect or merge into relatively 

large masses that in some places are rather irregular 

or oblong, such as the Haystack (Gabelman, 1956b, 

figs. 133, 135) and Flat Top 4-Vilatie Hyde deposits. 

Others merge and interconnect to form stringlike 

masses having a length many times their width, such 

as the F-33 (Hilpert and Moench, 1960, fig. 18), the 

Faith (McLaughlin, 1963, fig. 6), and the Section 25. 

The dominant trends of these masses are eastward or 

northward, similar to the trends of the intraformational folds, but many are heterogeneous.

Ore bodies generally constitute the central parts of 

the deposits where the deposits are thicker and higher 

in grade. Away from ore, the deposits feather out or 

grade into barren host rock along rather irregular or 

vaguely defined zones. Ore bodies range from masses 

with dimensions of only a few feet that contain several tons of ore to masses that are hundreds of feet 

wide, more than 1,000 feet long, and several feet thick, 

and contain as much as 100,000 tons of ore. Most ore 

bodies, however, average about 25 feet in width, 100 

feet in length, and 5-7 feet in thickness, and contain 

about 1,000 tons of ore. McLaughlin's (1963, fig. 6) 

map of the Faith deposit is a good example of the 

general relations of ore to mineralized ground.

Grade of the ore ranges from 0.10 U3O8 to at least 

10.0 percent U3O8.

STRATIGRAPHIC RELATIONS OF THE DEPOSITS

Uranium deposits in the Todilto Limestone show no 

direct relation to the stratigraphy of the formation 

but possibly are indirectly related to the gypsumanhydrite member and probably are indirectly related 

to the original thickness of the limestone member.

From place to place the deposits occur at the base, 

middle, top, or throughout the limestone member and, 

in many places, extend into the top of the underlying 

Entrada Sandstone or base of the overlying Summerville Formation. No known deposits occur in the gypsum-anhydrite member, but all the principal deposits 

are near its outcrop. (See pi. 3.) This position of the 

deposits in relation to the member probably stems 

from chance exposure, but for some unknown physical 

or chemical reason, the gypsum-anhydrite member 

may have influenced the emplacement of the deposits 

near its margin.

Near the principal deposits the limestone member 

is about 15-25 feet thick (pi. 3). Elsewhere it is generally less than 15 feet thick. This occurrence of deposits near thicker limestone may also be a result of

fortuitous exposure the Todilto Limestone has been 

explored at most only a few miles from the outcrop 

but more probably it expresses some relation of the 

deposits to the original thickness of the limestone.

STRUCTURAL RELATIONS OF THE DEPOSITS

Primary uranium deposits in the Todilto were directly controlled by structures that resulted from the 

first period of deformation (Late Jurassic to Early 

Cretaceous), but show few effects, except secondary 

ones, from later deformation.

The deposits are closely related to intrf.fonnational 

folds in the limestone and these folds ar^ related to 

broader open folds in the Jurassic rocks, which are 

dated as post-Todilto and pre-Dakota. The deposits 

are postsyngenetic because they cross tH limestone 

bedding (fig. 19), and are postintrafonmtional folding because they transect the intraformational folds 

(Gabelman, 1956b, fig. 136, cross section L-K) and at 

least locally transect the broader pre-Dakota folds 

(Hilpert and Moench, 1960, p. 458, fig. 15; Moench, 

1963c, p. 163-164).

The original thickness of the limestone (see above) 

probably had a direct bearing on the localizriion and development of the intraformational folds. Confinement 

of the folds largely within the limestone indicates its 

relative incompetence; it should follow that where the 

limestone is thickest it would have a tendency to absorb a greater percentage of the stresses exerted on 

the rock column. Thus, the degree of def conation expressed by the folds would most likely be a direct result of the original thickness of the limestone member. 

The deposits are directly related to the folds and generally to their degree or intensity of development; 

thus they are indirectly related to the original thickness of the limestone.

No convincing evidence supports the possibility that 

localization of the primary deposits was influenced by 

the second (Late Cretaceous to middle Tertiary) or 

third (middle Tertiary to late Tertiary or Quaternary) periods of deformation. Present information 

indicates that the oldest structural feature resulting 

from these periods of deformation are th«, faults and 

folds that formed contemporaneously with the development of the McCartys syncline. As indicated above, 

the syncline and the associated smaller features probably formed during development of th«> Zuni and 

Lucero uplifts and the Acoma sag, ard probably 

prior to the northward tilting of the San Juan Basin 

(pre-San Jose, or pre-early Eocene time).

In the Ambrosia Lake district, deposits do not occupy fault zones except for the intrr.formational 

faults within the Todilto Limestone. Where faults
PENECONCORDANT DEPOSITS IN SHALE AND COAL 103

5936'

5934'

5932'

5930'

5928' 

5926' 

5924'

5922' 

6 FEETI

'Vw. -DATUM IS APPROXIMATE MEAN SEA LEVEL 

i^ - - " '^ ' ^ >. ^"* ^xi^ '». / v -l^,^ -, » " ' , ^

EXPLANATION

Limestone breccia 

Massive

Massive, thick-bedded. Dashed

Coarse calcite

Isorad line

Showing radioactivity, in milliroentgens 

per hour. Hachures point in direction 

of higher radioactivity 

FIGUBE 19. Geologic section across uranium deposit in Todilto Limestone, showing displacement by diabase

intrusive, Sandy mine area. Geology by Frank Hensley.

intersect deposits, the deposits are displaced and 

therefore must be older.

Gabelman (1956b, p. 391-392, fig. 132), however, 

implied that the deposits may be younger than the 

faults and folds by noting that the deposits occur 

within the area of strongest faulting and along the 

axes of northeastward-trending folds, both of which 

are on the flank of the Zuni uplift and within the 

sharpest bend of the strike of the Thoreau homocline 

(meaning the bend of the Chaco slope southeastward 

around the Zuni uplift and southward along the west 

flank of the McCartys syncline).

Gabelman's northeastward-trending folds probably 

are related to the subparallel faults (see p. 61), and 

both probably are the same age. Because the faults 

displace the deposits, both the folds and the faults must 

be younger than the deposits and could not have influenced their emplacement.

The oldest recognizable structural features that are 

certainly younger than the deposits are the fractures 

in the Laguna district that formed contemporaneously 

with the Rio Grande trough during the third period of 

deformation. These fractures are intruded by diabasic 

dikes and sills which, in turn, are broken by the same 

set of fractures, a relation that indicates their contemporaneity. The deposits show no relation to the fractures, and the diabasic intrusives displace and metamorphose the uranium deposits (Moench, 1962; 1963c, p.

161) (fig. 19). These facts demonstrate that the deposits 

are clearly older than the fractures and the intrusives. 

Field relations indicate the fractures and intrusives 

probably formed mostly in middle to late Tertiary time, 

and probably prior to the Mount Taylor eruptions. 

Inclusions of the diabase were found in a volcanic pipe 

that probably supplied one of the earliest basaltic flews 

(Hilpert and Moench, 1960, p. 444). The fact that th<>se 

flows were extruded during the latest stages of the 

Mount Taylor eruptions indicates the diabasic rocks are 

at least older than what may be the oldest basaltic flows. 

Because the entire sequence of Mount Taylor probably 

formed during an eruptive cycle, a relatively short 

period of time, the diabasic intrusions probably took 

place before the Mount Taylor cycle, as well as before 

the basaltic extrusions. Conclusions are that the deposits 

are older than any of the intrusive igneous rocks within 

the Laguna and Ambrosia Lake districts and that tic. eir 

emplacement could not have been influenced by them.

PENECONCORDANT DEPOSITS IN SHALE AND COAL

Deposits in shale and coal are quite similar in mineralogy and form to those in sandstone and, in some instances, where they occur in nearly equal proportions 

in both rock types, are classified rather arbitrarily. The 

host rocks, however, are different, so the deposits are 

separated for descriptive purposes. The deposits oc^ur 

in shale and coal of Permian, Cretaceous, and Tertiary
104 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

ages; undoubtedly others have been arbitrarily included 

with the deposits in sandstone, through lack of information. The deposits occur around the periphery of the 

San Juan Basin in seven stratigraphic units and four 

counties, as follows:

Stratigraphic unit

Menefee Formation. .___ _ __

Crevasse Canyon Formation. ___

Gallup Sandstone.. . -_.._ _

Dakota Sandstone. _ __ __._

Do_..__. ___._.___.____...

Abo Formation_________ _____

Number of 

deposits or 

clusters of 

deposits

1

2

1

4

1

3

2

1

County

Sandoval.

Do.

McKinley.

San Juan.

Sandoval.

McKinley.

Sandoval.

Nine of the deposits are principally in carbonaceous 

shale, five are in low-grade coal or peat, and one is in 

mudstone, which can be considered the same as shale. 

Three of the deposits have been mined: the Bugler Bros. 

1 in northwestern Sandoval County and the Hogback 3 

and 4, and the Santa Fe Christ in southwestern McKinley County. These deposits, which are in the Dakota 

Sandstone, yielded 6,497 tons of ore that averaged 0.20 

percent U3O8 during the 1952-60 period. Of this material, 4,438 tons averaged 0.03 percent V2O5 and 2,434 

tons averaged 0.7 percent lime. Among the three properties, the ores ranged from 0.17 to 0.63 percent U3O8, 

0.03 to 0.12 percent V2O5 , and 0.5 to 5.2 percent lime. 

Undoubtedly some inclusion of sandstone ore in shipments caused the higher lime values and probably the 

higher vanadium values. The average ratio of uranium 

to vanadium, in the 4,438 tons of material for which 

there are data, was 10:1.

MINERALOGY AND HABITS

Uranium minerals are not visible in the deposits, and 

few identifications have been attempted in the laboratory. Nearly all deposits have been reported only as 

radioactive zones or anomalies. Exceptions are the Deer 

Creek deposit in the Abo Formation, reported as an 

occurrence of a yellow-green uranium mineral associated with various copper sulfides and carbonates, and 

the State lease deposit in the San Jose Formation, 

reported as autunite (?) coatings on bedding and fracture surfaces of mudstone. The uranium in most of the 

deposits, however, probably occurs as coffinite or uraninite. Gruner (in Bachman and others, 1959, p. 302) 

identified coffinite in coal in the North or South Butte 

deposit of La Ventana Mesa, Vine (1962, p. 150) reported uraninite and coffinite in lignitic shale samples 

from South Dakota, and Nekrasova (1958) identified 

pitchblende (uraninite) as the principal primary mineral in some Russian coals. In the fine-grained highly

carbonaceous materials like coal and carbonaceous shale 

these low-valent minerals are likely protected from 

oxidizing solutions by the low perinea! Hity of the 

shales and coals. The minerals also are protected from 

oxidation by the reducing effects of organic material. 

In the Cave Hills and Slim Buttes areas of northwestern 

South Dakota, autunite, zeunerite, torbernite, and metatyuyamunite have been identified in lignite and carbonaceous sandstone (Denson and others, 1959, p. 28). 

This suite is essentially the same as the high-valent secondary uranium minerals that are found in the sandstone deposits, where the minerals are obviously derived 

from coffinite or uraninite.

Deposits in shale and coal generally arc smaller and 

thinner and tend to be more tabular than the ones in 

sandstone, and they tend to occur in single rather than 

multiple layers. They range in size from small layers, 

an inch or so thick and a few feet long, to masses, as 

much as 10 feet or more thick and more than 1,000 feet 

long. The general configuration of many deposits is not 

known, as they have been observed only at outcrop. 

They probably, however, are mostly crude] ^ equidimensional in plan, as suggested by their clog^ association 

with carbonaceous beds or shale lenses and the general 

absence of bedding structures such as crossbeds and cutand-fill features that cause the elongation of the deposits in sandstone. The largest deposit c~ cluster of 

deposits is at North Butte in the La Ventana Mesa area, 

where as much as several hundred thousand tons of 

material, generally containing more than 0.02 percent 

uranium, forms a crudely tabular mass tHt ranges in 

thickness from about 1 foot to 4 feet and that averages 

about 11/2 feet (Bachman and others, 195S ; J. D. Vine, 

G. O. Bachman, C. B. Read, and G. W. Moore, written 

commun., 1953). The uranium is mostly in impure coal 

and is partly in carbonaceous shale and sandstone.

STRATIGRAPHIC AND STRUCTURAL PELATIONS

Nearly all the known deposits occur at or near the 

base of sandstone units and above shale, claystone, or 

mudstone units. A few occur at or near the, top of sandstone units. Sedimentary structural features seem to 

have little effect on most of the deposits, although some 

bedding planes or seams show local cortrol. Mirsky 

(1953) noted that the Hogback 3 and 4 deposit was 

underlain by a channel type sandstone that thinned 

southward, presumably away from the deposit.

Tectonic structures influence the deposits locally. The 

Butler deposit occurs in the hogback about 1 mile west, 

of the Nacimiento thrust fault where the Dakota and 

adjacent formations are offset along a northward-trending high-angle normal fault of uncertain age. The 

deposit is in a peat bed at the base of the Dakota and is
VEIN DEPOSITS 105

confined east of the normal fault, which is unmineralized (Gabelman, 1956a, p. 310-312). If the fault is 

related to the Nacimiento thrust it could be as old as 

Paleocene; however, it could be related to faulting in 

the Rio Grande trough and be as young as Pliocene 

(Wood and others, 1946). Because the deposit terminates downdip against the fault, it may have been emplaced against the fault barrier after Tertiary tilting 

(Gabelman, 1956a).

In La Ventana Mesa the deposits are controlled by 

several structural features, as noted by Bachman, 

Vine, Read, and Moore (1959, p. 300-301). The fact 

that the two largest deposits are near the axis of the 

La Ventana syncline suggests that the deposits may 

have been controlled by the syncline during emplacement. In addition, local tent-shaped thickenings of 

sandstone beds at the top of the uranium-bearing 

zone, minor synclinal crenualtions within the zone, 

and joints in the overlying La Ventana Tongue of the 

Cliff House Sandstone all locally control uranium concentrations. The tent-shaped structures are thought 

to have formed by plastic deformation and the synclinal structures by flowage of the incompetent coaly 

or shaly material under indurated sandstone units. 

Joint control of the uranium is shown by the downdip 

concentrations below the joints and uranium-bearing 

opal found on a joint surface. Age of these structures 

and their mineralization is uncertain. The La Ventana 

syncline is related to the deformation that caused the 

San Juan Basin, so could range in age from Late 

Cretaceous to late Tertiary, but the fact that the syncline occupies a structural position on the flank of the 

San Juan Basin that is similar to the monoclinal folds 

would more likely indicate the age of the folds to be 

Late Cretaceous or early Tertiary. The joints formed 

after the beds consolidated, perhaps in early Tertiary 

time. The deposits postdate these structures, so probably are post-early Tertiary.

Stratigraphic and structural evidence indicates that 

the deposits were derived from descending solutions. 

The deposits tend to concentrate in the uppermost bed 

of coal or carbonaceous material; stratigraphically 

lower carbonaceous beds are practically barren; and 

there is little evidence that the mineralized areas are 

associated with faults. The uranium may have been 

derived by downward leaching from the Bandelier 

Tuff (Smith, 1938), of Pleistocene age as postulated 

by Bachman, Vine, Read, and Moore (1959) a wide 

spread unit in the Jemez Mountains to the east. (See 

pi. 1.) The tuff contains an average of 0.003 percent 

uranium and may have formerly extended over the 

La Ventana Mesa area. It is an ash-flow unit, however, 

and more likely was confined east of the Sierra Nacimiento divide, which is higher than the general surface of the Bandelier Tuff. The uranium, therefore, 

was probably leached from the overlying La Ventana 

Tongue. If so, the leaching and emplacement must 

have taken place in late Tertiary and Quaternary 

time, after uplift and removal of the younger and 

relatively impervious Lewis Shale.

Many of the other deposits in shale and coal could 

be youthful, as suggested by their occurrence at ow 

crop and their possible association with the Recent 

cycle of weathering. This Recent age is uncertain, 

however, and at least some deposits such as the Hogback 3 and 4, could be much older than Recent. Tve 

Hogback 3 and 4 and others, such as the Diamond 2 

and Becenti, which occur in sandstone, are found at 

or near the outcrop of the Nutria monocline. If tr.is 

monocline influenced emplacement of the deposits, as 

indicated by the structural relations of the Diamond 

2 (see p. 92), the deposits may be as old as Late 

Cretaceous.

VEIN DEPOSITS

About two dozen vein deposits in sedimentary, 

igneous, and metamorphic rocks in northwestern New 

Mexico are listed on plate 1. They comprise fracture 

fillings, stockworks, mineralized breccia, and fillings 

or disseminations of uranium minerals in pegmatite 

bodies. All are in or along the flanks of the Bio 

Grande trough, but those in metamorphic rocks and 

in pipelike structures are older than the trough structures and not related to them.

Several mineralized pipes also occur in the Ambrosia Lake and Laguna districts, but they constitute 

parts of peneconcordant deposits in sandstone. Pipe 

structures in the Cliffside, Doris 1, and Jackpile cV 

posits probably yielded several thousand tons of ore, 

but the exact tonnage and grade are not known.

Seven of the listed vein deposits yielded about 

25,000 tons of ore during 1954-64, the productive 

period. Ninety-five percent of this ore was produced 

by the La Bajada, Charley 2, and Woodrow mines. 

The Woodrow yielded the highest grade ore, which 

annually ranged from 0.32 to 1.70 percent U3O8 and 

averaged 1.26 percent U3O8 . This ore averaged 0.04 

percent V2O5 ; the La Bajada ore averaged 0.04 pr**- 

cent, and the Charley 2 ore averaged 0.03 percent. 

The other deposits ranged from 0.10 to 0.38 percent 

V2O5 , and had average U:V ratios that ranged from 

2:1 to 1:1, similar to most of the peneconcordant 

deposits.

For descriptive purposes, the vein deposits are 

classified according to their occurrences in sedimentary, igneous, and metamorphic rocks, and the general
106 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

mineralogy, habits, and stratigraphic and structural 

relations of each type are summarized below.

DEPOSITS IN SEDIMENTARY BOCKS 

MINERALOGY AND HABITS

Eight vein deposits are listed in sedimentary rocks: 

the Agua Torres and Marie in the Madera Limestone; 

the Lucky Don, Little Davie, and Sonora in the San 

Andres Limestone; the Woodrow in the Morrison 

Formation; and the Charley 2 and Silver Creek prospect in the Popotosa Formation. The uranium in all 

except the Woodrow is mostly in the yellow uranyl 

vanadates autunite, meta-autunite, and metatorbernite 

(?), which occur as coatings on fracture faces and 

bedding planes, as fillings in open spaces, and as disseminations in the host rock. At the Silver Creek 

prospect, the uranium minerals are associated with 

copper oxides, and at the Sonora prospect they are 

probably associated with copper and lead, and possibly 

silver and nickel minerals. Mineralogy of the Woodrow deposit is similar to that of other deposits in the 

Morrison Formation of the Laguna district, except 

that some of the principal ore mineral is coarse-grained 

coffinite and the deposit contains a much higher grade 

of uranium as well as of sulficles of associated metals.

Host rocks of these deposits generally show alteration effects similar to those of the host rocks of the 

peneconcordant deposits. The Charley 2 may be an 

exception, in that the deposit is overlain by a hanging 

wall of sheared clay and is on a footwall of altered 

granitic rock. (P. K. Knowles, written commun., 195T). 

Most of the deposits are small and irregular in form, 

and range from breccia fillings along fault zones (such 

as the Woodrow and Agua Torres) to crudely tabular 

disseminated masses in the hanging wall or footwall of 

faults (such as in the Charley 2 and Lucky Don).

STRATIGRAPHIC AND STRUCTURAL RELATIONS

Most of the known deposits are surficial and, at most, 

extend a few tens of feet below the surface. The Woodrow, however, extends at least 240 feet below the surface, 

below which it has not been explored.

Host rocks of these deposits are either sandy or shaly 

limestone or sandstone ranging in age from Pennsylvanian to Tertiary. The limestone generally is broken 

or brecciated, and the sandstone is fractured and locally 

crushed and sheared. All the deposits except the Woodrow are associated with fractures that probably formed 

contemporaneously with the development of the Rio 

Grande trough and are middle Tertiary or younger in 

age. Fracture control of the mineralization, therefore,

indicates that the deposits were emplaced during or 

after formation of the trough structures.

DEPOSITS IN IGNEOTTS ROCKS 

MINERALOGY, HABITS, AND STRUCTURAL RELATIONS

Eight deposits are listed in igneous rocks: the La 

Bajada in the Espinaso Volcanics of Stearns (1943); 

the Cerro Colorado, 'at the contact of a rhyolitic intrusive with trachyte flows; and the Mimi 4, Hiser-Moore, 

Peralta Canyon, "Shaft" prospect, and th*, two CarterTolliver-Cook deposits, all of which ocxrir in various 

sills, flows, and other intrusives of felsic and mafic composition. Of these deposits, only the La Bajada has been 

productive.

Most of the deposits are probably surfnial, and consist of fracture or joint fillings or coatings of the uranium minerals autunite, torbernite, uranophane, and 

carnotite (?), and various other associated minerals. 

The "Shaft" occurrence contains torbernite (?) and 

carnotite (?) associated with secondary copper minerals, calcite, and quartz; the Carter-Tolliver-Cook deposits contain carnotite and uranophane associated with 

galena, pyrite, and chalcopyrite. The urarium minerals 

in these deposits may be coatings derived from the 

recent cycle of circulating ground waters or they may 

be secondary after earlier primary minerals, such as 

uraninite. The La Bajada, and probably the Cerro 

Colorado, however, more certainly are older and are 

related to igneous intrusions.

The La Bajada~consists of a complex network of thin 

sulfide mineral veins in a mafic dike and an impregnation of fine-grained sulfide minerals in the brecciated 

footwall of the dike where it is altered to clay. Some 

of the uranium occurs in tyuyamunite, but it may principally be in fine-grained uraninite. Exctnt for pyrite, 

the sulfide minerals have not been identified, but they 

probably represent sulfides of several metals; for example, one pulp sample of the ore contained about 1.5 

percent copper, 0.3 percent nickel, 0.13 percent arsenic, 

and 18.4 percent sulfur.

The size of the deposit is uncertain, but it must be at 

least several hundred feet deep, several tens of feet 

wide, and probably a little more than 200 feet long, as 

indicated by a vertical shaft and an cr>en pit. The 

deposit is one the west side of the Cerrillos Hills district, 

and probably is related to the base-metals mineralization of the district and to intrusives considered to be 

Oligocene in age. (See p. 30-31.) The La Bajada deposit 

is emplaced in the Espinaso Volcanics, considered to be 

Oligocene (?) in age by Disbrow and S <-oll (1957, p. 

10-12, 33). Mineralization of the La Bajada deposit
DISTRIBUTION OF ELEMENTS IN THE ORES 107

probably closely followed emplacement of the Espinaso 

Volcanics, and therefore may be Oligocene in age.

The Cerro Colorado deposits consist of several prospects in which unidentified yellow and yellow-green 

uranium minerals coat limonite-stained fractures and 

brecciated pockets along the contact of a rhyolitic intrusive body with trachytic flows. The uranium is probably 

genetically related to the rhyolitic intrusive. It is radioactive at the surface, and vertical fractures within it 

 are roughly 10 times as radioactive as other parts of the 

volcanic body. Because the rhyolitic rocks intrude the 

Santa Fe Group, their age can be determined as late 

Tertiary or possibly Quaternary, which indicates a 

late Tertiary or Quaternary age for the uranium 

mineralization.

DEPOSITS IN METAMOBPHIC BOCKS 

MINERALOGY, HABITS, AND STRUCTURAL RELATIONS

At least seven deposits are listed in metamorphic 

rocks, of which four are in quartz-microcline pegmatite 

bodies, two are in crosscutting veins, and one or more 

possibly are in quartz veins. All are in the Ortega 

Quartzite of Just (1937), and most of them are in the 

Petaca Schist [Member] of the Ortega or in schistose 

quartzite.

In the pegmatite bodies, the uranium minerals occur 

as sparsely disseminated crystals of dull fine-grained 

masses of samarskite and uraninite and as thin coatings of gummite, autunite, and sabugalite. They are 

associated with purple or green fluorite, bismutite, 

monazite, columbite and other columbate-tantalates, 

ilmenite, magnetite, molybdenite, and garnet.

Deposits in veins consist of sparse disseminations of 

autunite, torbernite, and sabugalite in the walls of 

schist bounding crosscutting veins of purple fluorite; 

one or more deposits consist of uraniferous quartzite in 

which the uranium may be associated with quartz 

veins. A crystal of uraninite was reportedly found in 

the vicinity of the uraniferous quartzite (P. E. Melancon and F. R. Fincher, written commun., 1952), but details of the occurrence are not known.

The pegm'atite bodies and the fluorite and quartz 

veins are thought to be related to the Precambrian 

Tusas Granite of Just (1937), and are also considered 

to be Precambrian in age (Jahns, 1946, p. 22-25).

DISTRIBUTION OF ELEMENTS IN THE ORES 

PURPOSE AND METHODS OF ANALYSIS

Spectrographic analyses of about 70 elements and 

chemical analyses of a few selected elements and 

oxides were obtained from mill pulp samples from

329-381 O 69 8

the uranium ores of 66 deposits. (See pi. 1 and tables 

5, 6.) Radiometric analyses also were obtained routinely to determine whether the ores were in radioactive 

equilibrium. All analyses were obtained to determine 

the similarities and differences in the ores as related 

to stratigraphic position, rock type, tectonic structure, 

and areal distribution as a means to help classify the 

deposits geologically and to aid in the appraisal of the 

uranium resources.

Individually, the samples represent substantial tonnages of ore from the larger deposits and all the ore 

from the smaller deposits. Each sample generally represents ore mined during the 1951-57 period. One 

sample (246891, table 6) represents a 10-ton shipment that was substantially below ore grade but is 

included to provide data on a deposit in limestone in 

a part of the area that has been unproductive.

If an element or oxide was detected in two or more 

ore sample groups, the sample data were plotted in 

graphs (tables 7-9) for comparative purposes. Eight 

of the twelve most abundant elements in the earth's 

crust (Fleischer, 1953, p . 3) are shown in table 7. Of 

the other four elements, oxygen and hydrogen are 

excluded, phosphorus is not shown because it was undetected, and silicon is not shown because it constituted 

more than 10 percent of each sample and was not 

specifically measured. Table 8 lists the minor elements 

as determined spectrographically, and table 9 lists the 

data on the elements and oxides as determined chemically. On each table the ore sample groups are listed by 

host rock, generally from youngest to oldest. Those in 

the Espinaso Volcanics of Stearns (1943), although 

older, are listed above the Popotosa Formation so 

that the groups in Tertiary sandstones can be listed 

contiguously. The ore groups are broken down to 

separate the ores by types of host rocks and to fag 

their associations with the more obvious tectonic 

structures. The types of host rocks and the tectonic 

structures are identified by symbols, which are described in the explanations of the tables.

The graphs, which were prepared to give the reader 

a rapid visual comparison between sample groups, 

show the ranges in concentration between samples 

(horizontal bar) and their geometric means (vertical 

intersection of bar). The geometric means are logarithmic averages which are sample medians on a log 

scale. These show a better central tendency than arithmetic averages when applied to asymmetric distributions (Krumbein and Pettijohn, 1938, p. 240; Miereh 

andRiley, 1961, p. 248).
108 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

TABLE 5. Semiquantitative spectrographic) radiometric, and chemical analyses of mill pulp samples of uranium ores from volcanic rocks,

sandstone, and shale, northwestern New Mexico

Italic numbers are mine numbers shown on plate 1. Spectrographic determinations are semiquantitative and were made by the rapid visual comparison method. Comparsons 

of similar data with those obtained by quantitative methods show that the assigned semiquantitative class interval includes the quantitative value in about 60 percent 

of the determinations. Figures are reported to the nearest number in the series >10,7.3,1.5,0.7,0.3,0.15 and are coded as follows: >10=1, 7=2, 3=3, 1.5=4, 0.7=5, 0.3=6, 

0.15=7, 0.07=8, 0.03=9, 0.015=10, 0.007=11, 0.003=12, 0.0015=13, 0.0007=14, 0.0003=15, 0.00015=16, 0.00007=17, 0.00003=18, 0.000015=19. Figures reported asless than «1) 

are coded: <1.0=a, <0.05=b, <0.02=c, <0.01=d, <0.005=e, <0.002=f, <0.001=g, <0.0005=h, <0.0002=i, <0.00005=j. 0, looked for but not found; <, less than amount 

shown, standard detectability does not apply; Tr., trace; leaders ( ), not looked for; number enclosed in parentheses is near threshold of deteetabilty; ND, no data

[Spectrographic analyses are in percent, coded; other analyses are in percent or parts per million, as indicated, and are not coded]

Sample * Name of mine or prospect

Spectrographic

Ag Al As Au B Ba Be Bi Ca Cd

2

Ce Co Cr Cs Cu Dy Er Eu

Espinaso Volcanics

264107... .......

264108.. ................. La Bajada 2 (1) ........ ..........

...... 14

...... 16

3 7 

2 0

0 

0

0 8

0 7

0 

0

0 

0

4

2

0 

0

9 

9

9 

10

10 ......

10 ......

4 

4

0 

0

0 

0

0 

0

Popotosa Formation

229396..........

254045..........

......... Charley 2 (/).,___ ..... .. (1Q\

...... 0

1 0 

1 0

0 

0

g 8 

11 7

15 

15

0 

0

5

7

0 

0

0 

0

12 

11

12 ND 

12 ......

9

8

0 

0

0 

0

ND

0

Baca Formation

229399.... .......-.--.... Red Basin 1(3). ................

/1Q\ 3 0 0 g 5 (17) 0 3 0 0 15 13 ND 12 0 0 ND

Dakota Sandstone

229365..........

229368... .......

229366.... ......

254044..........

229364..........

229367..........

...- -- Becenti (/)___._._ ................

......... Christian 16 (U) (*).............

___ __ ....do ___ . _________ ...

......... Hogback 4 (S)..... ..............

-------- Silver Spur 5 (8). .. .............

...... 0

...... 0

...... 0

...... 0

 0

...... 0

3 0 

3 0 

4 0 

3 0 

2 0 

3 0

0 

0 

0 

0 

0 

0

12 10 

12 9 

13 10 

0 10 

12 8 

13 9

0 

0 

0 

0 

16 

0

0 

0 

0 

0 

0 

0

6

7 

7 

7 

7 

5

0 

0 

0 

0 

0 

0

0 

0 

0 

0 

0 

0

14 

14 

15 

14 

14 

15

13 ND 

13 ND 

14 ND 

13 ......

12 ND 

14 ND

13 

12 

13 

9 

12 

12

0 

0 

0 

0 

0 

0

0 

0 

0 

0 

0 

0

ND 

ND

ND 

0 

ND 

ND

Morrison Formation

229369..........

254048..........

254040..........

229372..........

245226... .......

254046..........

245225..........

229370..........

229371..........

254106... .......

254036-.-.-..-..

229373.. ... .....

254047... ...... .

254037..........

229374.. .....

254038..........

254039....... ...

229375 

239460 ......

......... Alta (*)..... ....................

..... .... Beacon Hill (S)..... .............

......... Blue Peak (Garcial) (10).... ...

......... Dysartl (28)... .......... .......

-------- Evelyn (34) .....................

......... Foutz 3 YJ (57)-.. . ..............

......... Jackpile (43) ....................

......... Mesa Top 7 (SO)... ..............

......... Pat (a*)............ ...... ....

_____ Poison Canyon (66). __ . ......

......... Silver Bit 7 (95). .

- ._... Silver Bit 15 (96)......... .......

......... Windwhip (101) .................

......... Woodrow (102) ..................

...... 0

...... 0

...... 0

...... 0

...... 0

...... 0

...... 0

...... 0

...... 0

...... 0

...... 0

...... 0

...... 0

...... 0

...... 0

...... 0

...... 0

 0

...... 15

3 0 

2 0 

3 0 

3 0 

3 0 

2 0 

2 0 

3 0 

2 0 

2 0 

1 0 

4 0 

1 0 

1 0 

3 0 

3 0 

3 0 

3 0 

3 8

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0

13 7 

12 7 

0 9 

g 7 

12 8 

12 7 

12 8 

13 8 

13 7 

0 8 

12 7 

13 9 

0 7 

0 7 

g 8 

12 7 

12 7 

13 8 

0 7

(17) 

0 

0 

16 

0 

0 

16 

16 

16 

16 

15 

16 

16 

0 

16 

15 

15 

16 

Tr.

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0

3 

3 

2 

5 

2 

2

3 

5 

3 

6 

5 

6 

2 

3 

4 

6 

6 

6 

6

0 

0 

d 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

9 

0 

0 

0 

0 

0 

0 

0 

0

15 

13 

14 

15 

14 

14 

13 

13 

14 

g 

12 

14 

14 

15 

15 

12 

12 

15 

10

13 ND 

12 ......

13 ......

13 ND 

11 ......

12 ......

13 ......

13 ND 

13 ND 

14 ......

13 ......

13 ND 

13 ......

13 ......

14 ND 

11 ......

13 ......

14 ND 

13 ND

12 

11 

11

it 

11 

11 

12 

12 

11 

11 

12 

11 

11 

12 

11 

12 

12 

10

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

6

ND

0 

0 

ND

0

ND 

ND

0 

0 

ND 

0 

0 

ND 

0 

0 

ND 

ND

Cutler Formation

229397 ......

245224..........

229400..........

......... Hillfootl (I).... .............

......... Bed Head 2 (5). ................

_____ Whiteflo. ____ . ...............

...... (18)

 . 0

...... (18)

2 0 

1 0 

2 0

0 

0 

0

13 8 

12 8 

13 7

16

15 

(17)

0 

0 

0

3

2 

1

0 

0 

12

0 

0 

0

13 

12 

13

12 ND 

11 ......

12 ND

6 

6 

11

0 

0 

0

0 

0

0

ND "ND

See footnotes at end of table.
DISTRIBUTION OP ELEMENTS IN THE ORES 109

TABLE 5. Semiquantitative spectrographic, radiometric, and chemical analyses of mill pulp samples of uranium ores from volcanic rocks,

sandstone, and shale, northwestern New Mexico Continued

Sample » Name of mine or prospect

Spectrographic ^Continued

P Fe Ga Gd Ge Hf Hg Ho In Ir K La Li Lu Mg Mn Mo

Espinaso Volcanics

254107 

254108. 

 -- . LaBajadal (/). .. 

... . La Bajada 2 (/)_.. 

2 Tr. 0 

3 Tr. 0

12 

0

0 

0

0 

0

0 

0

0 

0

0 

0

4 

5

10 

10

0 

0

0 

0

4 

3

8

7

10 

13

Popotosa Formation

229396. 

254045 

... ...... Charley 2 (/) ... ....... .....

 - . do .. 

...... ND 4 14 0 

3 14 0

0 

0

0 

0

0 

0

ND 

0

0 

0

0 

0

3 

3

12 

12

0 

0

ND 

0

6 

5

7 

6

12 

12

Baca Formation

229399 ... ... Red Basin 1(S). . ... ... ND 4 (15) 0 0 0 0 ND 0 0 3 0 0 ND 6 6 14

Dakota Sandstone

229365 

229368 . 

229366. 

254044 . 

229364.. ....... .

229367 

. ... Becenti (1)..... ..................

......... Christian 16 (U) (*). ._.___.

..-.-.. Diamond 2 (S). ..................

_ do _ 

... ... Hogback 4 (3) - ....

-------- Silver Spur 5 («).. ............

...... ND

...... ND

----- ND

.. .-- ND

...... ND

5 i 0 

5 i 0 

6 i 0 

400 

5 13 0 

5 i 0

0 

0 

0 

0 

0 

0

0 

0 

0 

0 

0 

0

0 

0 

0 

0 

0 

0

ND 

ND 

ND 

0 

ND 

ND

0 

0 

0 

0 

0 

0

0 

0 

0 

0 

0 

0

5 

4 

0 

0 

4 

4

12 

0 

0 

0 

12 

0

0 

0 

0 

0 

0 

0

ND 

ND 

ND 

0 

ND 

ND

7 

7 

8 

8 

6 

8

11 

11 

11 

8 

11 

11

12 

14 

14 

12 

13 

0

Morrison Formation

229369 

254048 

254040. 

229372 

245226 . 

254046. 

245225. -

229370---- .

229371 

254106 

254036 -

229373 

254047 

254037 

229374. 

254038-.-. -.

254039 .... ...

229375 

239460 

... ... ... Alta (S). .........................

......... Beacon Hill («). . .

...-- Begayl (7)... ...... ...... .... ....

-...-.-. Blue Peak (Garcia 1) (W). ......

--------- Chaves (/«). ...... ...... . _ ....

... ... Dysartl (g«)....................

__ ..--- Enos Johnsons (S3).. __ .......

------- Evelyn (34).....................

......... Foutz 1 (36)... ..................

......... Foutz 3 YJ(37)_ _ _ __

-------- Francis (SS). ....................

--------- Jackpile (^S).. ..................

......... Mesa Top 7 (60).................

......... Pat (64)... ......................

......... Silver Bit 7 (96)......... ........

......... Silver Bit 15 (96). 

..----. Windwhip (101). ................

......... Woodrow (10S). .................

 ND

...... ND

 .-- ND

.. . ND

----- ND

 ND

..--- ND

...... ND

4 i 0 

3 14 0 

4 16 0 

4 (15) 0 

4 Tr. 0 

4 15 0 

3 14 0 

4 i 0 

4 (15) 0 

4 Tr. 0 

4 14 0 

5 i 0 

4 15 0 

4 15 0 

5 i 0 

4 14 0 

4 14 0 

5 i 0 

2 Tr. 0

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0

ND 

0 

0 

ND

0

ND 

ND 

0 

0 

ND 

0 

0 

ND 

0 

0 

ND 

ND

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0

3 

3 

4 

3 

3 

3 

3 

3 

3 

3 

3 

4 

3 

3 

3 

3 

3 

4 

3

0 

0 

0 

0 

0 

0 

0 

0 

12 

0 

10 

0 

0 

0 

0 

0 

0 

0 

0

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0

ND 

0 

0 

ND

0

ND

ND 

0 

0 

ND 

0 

0 

ND 

0 

0 

ND 

ND

6 

5 

5 

6 

5 

7 

4 

6 

6 

8 

6 

6 

6 

8 

7 

6 

6 

7 

6

7 

7 

8 

9 

8 

6 

7 

8 

7 

10 

7 

9 

7 

8 

8 

6 

6 

9 

9

12 

8 

10 

11 

11 

10 

11 

10 

12 

14 

11 

15 

8 

0 

9 

14 

13 

14 

12

Cutler Formation

229397- 

245224 

229400.---. -----

-.. . Hillfoot 1 (/)._ 

.......... Red Head 2 (S) _._,.. ...... 

------ Whiteflo _ .

...... ND

...... ND

3 14 0 

3 12 0 

4 15 0

0 

0 

0

0 

0 

0

0 

0 

0

ND

ND

0 

0 

0

0 

0 

0

3 

3 

3

12 

11 

12

0 

0 

0

ND

ND

4 

3 

4

7 

7 

7

15 

0 

11

See footnotes at end of table.
110 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

TABLE 5. Semiquantitative spectrographic, radiometric, and chemical analyses of mill pulp samples of uranium ores frcm volcanic rocks,

sandstone, and shale, northwestern New Mexico Continued

Sample 1 Name of mine or prospect

Spectrographic 2 Continued

Na Nb Nd Ni Os P Pb Pd Pr Pt Bb Re Eh Fu Sb Sc Si

Espinaso Volcanics

254107.- ------

254108-------

__---.._ La Bajadal (/)- - -----

..-___-.. La Bajada 2 (/)....-.-___.--_-___.

..... 6

._... 5

12 10 

12 Tr.

6 0 

9 0

0 

0

13 

13

0 0 

0 0

0 ......

0 ......

0 

0

0 

0

0 

0

0 

0

13 

12

1 

1

Popotosa Formation

229396-------- 9*UfU>; __-__--.. Charley 2 (/)_. _____-____-___-_.

__-.._____ do .____-_--..__--._..

.... 4

.--.- 7

13 0 

12 0

12 0 

11 0

0 

0

11

9

0 ND 

0 0

0 ND 

0 ......

0 

0

0 

0

0 

0

0 

0

12 

13

1 

1

Baca Formation

229399------ 4 0 0 13 0 0 12 0 ND 0 ND 0 0 0 0 15 1

Dakota Sandstone

229365---------

229366---------

254044-------..-

oonqcj.

229367--------

_.-____-- Christian 16 (U) (*)_...._.._.-...

__---.-_- Diamond 2 (3) ................. ...

--..-....._--do- ------_-__-----------.-.

___...__. Hogback4 (S).. ...... .............

......... Silver Spur 5 (8)_ -_ --________.

7

6

.-... 9

..... 0

7

..... 5

0 0 

0 0 

0 0 

12 0 

0 0 

0 0

(14) 0 

14 0 

13 0 

12 0 

13 0 

14 0

0 

0 

0 

0 

0 

0

13 

14 

0 

0 

13 

(15)

0 ND

0 ND 

0 ND 

0 0 

0 ND 

0 ND

0 ND 

0 ND 

0 ND

0 ......

0 ND 

0 ND

0 

0 

0 

0 

0 

0

0 

0 

0 

0 

0 

0

0 

0 

0 

0 

0 

0

0 

0 

0 

0 

0 

0

15 

14 

0 

0 

13 

0

1 

1 

1 

1

1 

1

Morrison Formation

229369..-----

254048.-------

229372--------

245226---------

254046.---------

ft A coo e

229370.--------

229371----------

ofviiftfi

254036.---------

229373---------

254047----------

9*%-iA37

229374.--------

254038-------

254039-------

239360-------

.._-____. Alta (*)-.--....-.-.-...--.......

--__-__.. Beacon Hill (6)....................

......... Begay 1 (T)...... ..................

......... Blue Peak (Garcia 1) (10). ........

--------- Chaves (18).......................

......... Dysart 1 (g8). ........... _______

_.____-_. Foutz 1 (SS).. .....................

......... FoutzS YJ (37).. .................

......... Jaekpile (48).. ... ................

......... MesaTop7 (6G). .......... ........

......... Pat (84). - -- - .----

......... Silver Bit 7 (9S).. .................

......... Silver Bit 15 (96)..................

......... Windwhip (101) ...................

......... Woodrow (lOi)... .................

4

4

6

4

5

4

.... 4

.--.. 4

..... 4

5

____ 6

.--.. 6

.---. 4

4

____ 4

..-.- 5

.-... 5

... - 7

5

0 0 

13 0 

13 0 

0 0 

0 0 

0 0 

13 0 

0 0 

0 0 

0 0 

13 10 

0 0 

13 0 

13 0 

0 0 

0 0 

0 0 

0 0 

0 0

14 0 

12 0 

13 0 

14 0 

14 0 

11 0 

14 0 

13 0 

13 0 

13 0 

12 0 

13 0 

12 0 

13 0 

13 0 

13 0 

13 0 

13 0 

11 0

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0

12 

10 

11 

12 

12 

11 

12 

13 

10 

11 

10 

11 

11 

13 

12 

9 

10 

12 

9

0 ND

0 0 

0 0 

0 ND 

0 ___-_-

0 0 

0 __--_-

0 ND 

0 ND

0 0 

0 0 

0 ND 

0 0 

0 0 

0 ND 

0 0 

0 0 

0 ND 

0 ND

0 ND 

0 ......

0 --___-

0 ND 

0 ______

0 ......

0 ......

0 ND 

0 ND 

0 ......

0 ._-___

0 ND

0 ......

0 ______

0 ND 

0 ______

0 ...-__

0 ND 

0 ND

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0

15 

14 

0 

14 

0 

0 

0 

15 

15 

0 

14 

0 

0 

0 

0 

0 

0 

0 

14

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1

Cutler Formation

229397----------

9.1 199.1

......... Hillfoot 1 (1).. ....................---__ 3

.___. 3

..... 3

0 0 

13 Tr. 

0 11

12 0 

12 0 

13 0

0 

0 

0

11 

10

7

0 ND 

0 ..__-_

0 ND

0 ND 

0 ....__

0 ND

0 

0 

0

0 

0 

0

0 

0 

0

0 

0 

0

13 

12 

13

1 

1 

1

See footnotes at end of table.
DISTRIBUTION OF ELEMENTS IN THE ORES 111

TABLE 5. Semiqiiantitative spectrographic, radiometric, and chemical analyses of mill pulp samples of uranium ores from volcanic rocks,

sandstone, and shale, northwestern New Mexico Continued

Sample 1 Name of mine or prospect

Spectographic * Continued

Sn Sr Sm Ta Tb Te Th Ti Tl Tm U V W Y Yb Zn Zr

Espinaso Volcanics

254107 

254108... .......

....-___.- LaBajadal (0--------------.

...--__--. LaBajada2 (/)..............-._

..-.-- 0

.__._- 0

8000 

7000

0 

0

0 

0

5 

6

0 

0

0 

0

7 

7

11 

10

ND 

ND

12 

12

15 

15

Tr.

0

10 

10

Popotosa Formation

229396- - -----

254045-____ -

..... .. Charley2 (0~ ....

__--__--.--. .-do- -- ........---.-....

...... 0

.__-_- 0

11 0 0 ND 

9000

0 

0

0 

0

5 

6

0 

0

ND

0

8

7

10 

10

0 

0

12 

12

15

f

0 

9

10 

9

Baca Formation

229399-. ........ __---... KedBasinl (3)........................ 0 10 0 0 ND 0 0 8 0 ND 7 7 0 11 g 0 10

Dakota Sandstone

229365- . _____

229368--____---

229366--------

254044- ....... .

229364-. .......

229367-. ........

......... Christian 16 (U) (S). .............

- ------- Diamond2 (S). ............ .....

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

......... Hogback 4 (S)......... ..........

. .... . Silver Spur 5 (8).......... ....

...-- 0

...-- 0

...... 0

...... 0

..--__ 0

...... 0

13 0 0 ND 

12 0 0 ND 

16 0 0 ND 

14 0 0 0 

12 0 0 ND 

12 0 0 ND

0 

0 

0 

0 

0 

0

0 

0 

0 

0 

0 

0

7 

7 

8 

7 

6 

8

0 

0 

0 

0 

0 

0

ND 

ND 

ND 

0 

ND 

ND

6

7 

6 

6 

7 

6

9 

9 

9 

9 

11 

7

0 

0 

0 

0 

0 

0

13 

13 

14 

14 

12 

14

g 

g

1 

14 

g

0 

0 

0 

0 

0 

0

8 

9 

10 

9 

10 

11

Morrison Formation

229369. ....... __

254048 .

229372-.. .... ...

245226---..-.---

245225 ----

229370 . 

229371 --

254106 

254036--. .... . ._

229373 

254047 . 

254037 

229374 

254038 . 

254039 __. 

229375 

239460-. -------

......... Alta (S). .........................

......... Beacon Hill (6)... ................

......... Begay 1 (1)...... .................

--------- Blue Peak (Garcia 1) (10)........

......... Chaves (18)... ...................

......... Dysart 1 (S8).. ...................

......... Evelyn (34)......................

......... FoutzS YJ (37).- 

_ ------- Francis (38).. ............... .....

......... Mesa Top 7 (60)..................

......... Pat (64)..........................

. ....... Poison Canyon (66).. ............

......... Silver Bit 7 (95) ..................

. ... . Silver Bit 15 (96)..... .... ......

......... Windwhip (101). .................

......... Woodrow (10S). ..................

-_-__ 0

.--__ 0

..... 0

__-_- 0

_--__ 0

.--.-_ 0

----- 0

______ 0

-_.-. 0

_____ 0

-.-- 0

_____ 0

----- 0

_____ 0

...... 0

_____ 0

_-___ 0

...... 0

0

10 0 0 ND 

10 0 0 0 

10 0 0 0 

10 0 0 ND 

10 0 0 _._.-..

9000 

9 0 0 . _ -..

11 0 0 ND 

10 0 0 ND 

10 0 0 0 

10 0 0 0 

12 0 0 ND 

9000 

10 0 0 0 

10 0 0 ND 

10 0 0 0 

9000 

12 0 0 ND 

10 0 0 ND

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0

7 

6 

7 

7 

7 

7 

7 

7 

8 

8 

6 

7 

6 

7 

7 

7 

7 

8 

7

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

Tr.

ND 

0 

0 

ND

0

ND 

ND 

0 

0 

ND 

0 

0 

ND 

0 

0 

ND 

ND

6 

5

7 

7 

7 

6 

7 

7 

6 

7 

6 

6 

6 

7 

6 

5 

6 

6 

4

8 

8 

5 

9 

6 

8 

8 

7 

6 

8 

6 

7 

8 

7 

8 

6 

6 

8 

10

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0

12 

13 

0 

13 

12 

13 

12 

12 

12 

0 

10 

14 

13 

13 

13 

13 

13 

12 

12

g 

f

gf 

f 

f 

g 

g

f

gf 

f

gf 

f 

g 

g

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0

10 

9 

9 

10 

10 

10 

11 

9 

11 

11 

10 

9 

9 

10 

11 

10 

10 

10 

10

Cutler Formation

229397-. -------

245224 ____ 

229400 . 

...... Hillfootl (1). ........ .... ......

. ....... BedHead2 (S). ....... ..........

......... Whiteflo .__ _ . .

_-__. 0

.-_._ 0

_-.- 0

10 0 0 ND 

900 --_-...

10 0 0 ND

0 

0 

0

0 

0 

0

6 

6

7

0 

0 '0

ND

ND

7 

7 

8

8

7 

7

0 

0 

0

12 

11 

11

g 

14

g

0 

0 

8

10 

10 

11

See footnotes at end of table.
112 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

TABLE 5. Semiquantitative spectrographic, radiometric, and chemical analyses of mill pulp samples of uranium ores from volcanic rocks,

sandstone, and shale, northwestern New Mexico Continued

Radiometric

eU'

Chemical

U* V2 O S S« C'

(organic)

Percent

As s F9 So" Zn«

Parts per mil'ion

Espinaso Volcanics

254107- 

254108____. ________

______ LaBajadal (1). .................

...... LaBajada2 (1). .................

_____ 0.13

.11

0.16 <0.05 18.4 _ _-_____

.12 <.05 .86 ______-._-__

1,300

100

480 <0.5

<.5

200

70

Popotosa Formation

229396... -

254045_____________

______ Charley 2 (.)..

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

_____ 0.11

.15

0.10 _ .. . . _

.17 0.05 0.11 0.3

40 _.

30 920

1

25

100

280

Baca Formation

229399... .......... ...-_ Red Basin 1 (S). ....... .......... 0.28 0.14 ___-___-_-.__ ____-__. _ __ 30 5 50

Dakota Formation

229365_____________

229368... ..........

229366-. ___________

254044 .... .........

229364_____________

229367-. . .-..-----_

...... Becenti (/)_______________________

-_.-__ Christian 16 (U) (t)....... .......

______ Diamond2 (3)_ __________________

... do____ ... . 

______ Hogback4 (3). ___________________

______ Silver Spur 5 (S)_. _______________

_____ 0.16

_____ .12

_____ .13

_____ .14

_____ .15

_____ .14

0.21 _____________._----_----------_----_

.12 

.16 ------------------------- -

.16 0.05 0.10 1.4

.18 _.._...__________._._.__._-________.

.18 ___.___-.__--____________.-.-------_

60 _.

50 _.

40 _.

22

10 _.

40

<20

18

250

4

75

75

3

50

10

20

10

50

10

Morrison Formation

229369_. ____________

254048 .

254040_____________.

229372 

246226_____________

264046___. .--.... _

246225-.---.---.--.

229370-.-.---.-----.

229371---..----..

254106__-_. _______

254036- ___________

229373_____________

254047- ___________

264037-___. ________

229374_. ___________

254038_____ _________

254039_____________.

229375 .

239460_. ... _____ ...

______ Alta (S). .........................

..... Beacon Hill (6) .............

...... Begay 1 (7). -.__________._._____

..--.. Blue Peak (Garcial) (10)..........

...... Chaves (18) ......................

...... Dysart 1 CM).. __________________

______ Enos JohnsonS (33)____________. _

______ Evelyn (34). _____________________

______ Foutz 1 (Sfi)...... ................

...... Foutz 3 YJ (37)__. _.-..-____.____

______ Francis (38). _____________________

______ Jackpile (43) .....................

...... Mesa Top 7 (60) __________________

_ _ _ Pat (64).... ..... ..........

...... Poison Canyon (66). _____________

______ Silver Bit 7 (95)....... ___________

______ Silver Bit 15 (96) .................

...... Windwhip (101). .................

.. ... Woodrow (102) . . . ......

_____ 0.18

_____ .41

_____ .16

._.__ .11

_____ .14

_____ .21

_____ .15

_____ .13

.... . .23

_____ .16

_____ .32

_____ .33

_____ .16

_____ .10

_____ .25

.85

_____ .29

_____ .26

.87

0.20 _________--_.__________-_ --------

.50 0.21 1.30 0.8

.19 2.24 .15 <.3

.12 .

.20 .56 .49 ____________

.24 .10 .58 <.3

.18 .17 .16 ____________

.15 ______.__._____________-_.--------_.

.27 . .

.17 .24 .12 ____________

.35 .86 .09 .4

.31 _ _ - -

.17 .13 .70 .5

.10 .16 .18 <.3

.20 _-_.__ ______ ____-__ _-_--_--

.96 1.28 ____________ .3

.35 .65 ____________ .3

.28 _ --

1.16 ____________ 6.64 ____________

60 __

92

35

20 _.

83

26

19

250 _.

150 -.

34

85 _.

20 _.

46

14 _.

50 _.

24 __

16 __

20 ..

890

230

<20

90

210

40

50

170

220

625

500

100

150

50

100

50

125

100

25

100

1

125

2

250

12

4

18

8

20

70

10

20

21

20

39

40

40

10

60

20

SO

10

20

50

60

10

35

Cutler Formation

229397_. ___________

245224__. .

229400_____________

...... Hillfootl U). ____________________

______ Red Head 2 (3). .____..._________

______ Whiteflo___ _ . .. ._

_____ 0.10

_____ .13

.07

0.12 ND ND ND

.13 5 .07 ND

.06 ND ND ND

50

65

50

ND

320

ND

4

<.5

10

70

87

1,000

1 Spectrographic analyses, chemical analyses for As, Se, U, and Zn, and radiometric analyses for U for samples 229364-229375 and 229396-229400 inclusive requested 

by A. T. Miesch.

2 Analy ses of samples 245224-245226 and 254106-254108 inclusive by N. M. Conklin; 

others by R. G. Havens.

3 Analysts: C. G. Angelo and others under the direction of L. F. Rader, Jr.

4 Analysts: R. P. Cox, E. J. Fennelly, H. H. Lipp, J. S. Wahlberg, and others under 

the direction of L. F. Rader, Jr. Fluorimetric method.

5 Analy sts: H. H. Lipp and others under the direction of L. F. Rader, Jr. Volumetric method.

9 Analysts: G. T. Burrow, E. C. Mallory, and others under the direction of L. F. 

Rader, Jr. Gravimetric method.

7 Analysts: E. J. Fennelly and Wayne Mountjoy. Rapid scannng, CO2 method.

8 Analysts: R. R. Beins, H. E. Crowe, W. D. Goss, Claude Huffman, J. P. Schuch, 

and others under the direction of L. F. Rader, Jr. Colorimetric irethod.

9 Analysts: R. P. Cox, W. D. Goss, and L. F. Rader, Jr. Colo-imetric method.

10 Analysts: G. T. Burrow and others under the direction of L. F. Rader, Jr. Colorimetric method.

"Analysts: R. R. Beins, G. T. Burrow, H. E. Crowe, Claude Huffman, J. S. 

Wahlberg, and others under the direction of L. F. Rader, Jr., Colorimetric method .
DISTRIBUTION OF ELEMENTS IN THE ORES 113

TABLE 6. Semiquantitative spectrographic, radiometric, and chemical analyses of mill pulp samples of uranium ores from limestone,

northwestern New Mexico

Material within brackets is descriptive, not part of mine name. Italic numbers are mine numbers shown on plate 1. Spectrographic determinations are semiquantitative and 

were made by the rapid visual comparison method. Comparisons of similar data with those obtained by quantitative methods show that the assigned semiquantits tive 

class interval includes the quantitative value in about 60 percent of the determinations. Figures are reported to the nearest number in the series >10, 7, 3, 1.5, 0.7, 0.3, 

0.15, and are coded as follows: >10=1, 7=2, 3=3, 1.5=4, 0.7=5, 0.3=6, 0.15=7, 0.07=8, 0.03=9, 0.015=10, 0.007=11, 0.003=12, 0.0015=13, 0.0007=14, 0.0003=15. Fig-'res 

reported as less than «) are coded: <1.0=a, ^0.05=b, <0.02=c, <0.005=d, <0.002=e, <0.001=f, <0.0005=g, <0.0002=h, <0.00005=i. 0, looked for but not found: <, 

less than amount shown, standard detectability does not apply; Tr., trace; leaders (___-), not looked for; number enclosed in parentheses is near threshold of de*ectability; ND, no data

[Spectrographic analyses are in percent, coded; other analyses are in percent or parts per million, as indicated, and are not coded]

Spectrograohic 2

Ag Al As Au B Ba Be Bi Ca Cd Ce Co Cr Cs Cu Dy Er

Ore in the TodiUo Limestone

256424 - 

256425 - 

256426.-. .......

256427..---.---.

229390..........

256428. -- 

245228 

256429-.. ..-.

256430. ..---. -_

229393--- 

256431 ..-.-._--

256432 .........

256433-. ........

256434.. - 

256435 - 

256436- .. 

229391.. ...... ..

256437. 

248891. ....... ..

236438.- . 

256439. . --------

286440... .. .....

229395 -- 

256441 .........

256442-.. -----

229392.... ......

256443 --------

256444. 

229394-. ........

256445.-.--- ---

256446. .........

......... Barbara J 1 (1)..... ..........

-__----._ Billy The Kid (S). ........ ...

......... Black Hawk (4)... ... ....

-------- Bunney U)_. ....... .........

-......- Cedar 1 (B)... ......... ........

...--.-- Christmas Day (tf).. ..._..___.

------ Crackpot (7). -...._ .... ..

......... Flat Top4 (1^). .............

......... Gay Eagle (13)....... ........

......... Hanosh (Section 26) (IB).....

......... Haystack 2 (17).. .............

... ...... Last Chance (19).............

......... Red Bluff 3 (Af). .............

......... Bed Bluff 5 (25). ........... ..

......... Bed Bluff 7 (26). .............

--...-... Red Bluff 8 (IS)... ..........

--------- Red Bluff 10 (13) ......... ....

-------- Bed Point Lode (*8).. ........

------ . Beed Henderson. ------------

......... Bimrock (S9). ....... .........

......... Section 18 (3^).... ............

-------- Section 18 (S3). ........ .......

--------- Section 19 (34)...............

......... Section 21 (37). ...............

-------- Section 24 (39)................

......... Manol (Section 30) (««). ......

-------- Manol (Section 30, T-S) (««)__.

--------- Manol (Section 30, T-19) («&)_.

..... .... T 2 (45)- ......................

--------- TomElkins (48)..............

......... UDC 5 (#).-.._- .-..... ...

...... ... 030009

......... 040009

..-.-.... 040009

-------- 040009

......... i 5 0 0 b 9

--..... 050009

.-.----. 0 4 0 0 0 10

.._----.- 030009

......... 040009

.-..---.. i 4 0 0 b 9

.-. ... 030008

......... 040008

......... 050009

------- 040008

......... 040009

......... 030008

-_- - i 4 0 0 b 9

......... 050008

......... 050009

......... 050009

......... Tr. 3 0 0 0 7

......... 030008

.---..-.. i 5 0 0 b 11

......... 020009

......... 030008

......... i 4 0 0 b 10

......... 040009

......... 030009

..-.--._ i 5 0 0 b 10

......... 020007

......... 040009

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

(1

0

0

0

0

0

(1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

0

0

0

0

0

0

0 .

0

0

0

0

0

0

0

0

0

0

0

0 ,

0

0

0

12

0

0

0

0

0

(12)

0

0

b

b

b

b

b

b

b

b

b

b

b

b

b

b

b

b

b

b

b

b

b

b

b

b

b

b

b

b

b

14

15

14

14

(15)

14

0

15

15

(15)

15

14

14

14

15

14

(15)

15

0

15

14

15

g

15

15

(15)

15

14

g

15

14

13 ------

14 ......

14 ......

14 ___.._

12 ND

14 ......

13 ......

13 ......

14 ......

13 ND

13 ......

14 ......

15 ......

14 ......

14 ......

13 ......

14 ND

14 ......

13 ......

14 ......

13 --

13 ......

15 ND

14 ......

14 ......

12 ND

13 ......

13 ......

14 ND

14 ......

14

12

12

12

12

13

13

12

13

13

13

13

12

13

13

12

12

13

13

13

12

12

12

13

12

12

13

12

12

13

12

12

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Ore in the Todilto Limestone and Entrada Sandstone

246229.. ........ ......... Sandy (7ff). ............................ 0 3 0 0 Tr. 9 0 0 1 0 0 13 12 12 0 0

Ore in ths San Andres Limestone

245227 ......... Lucky Don (1)... ..............-.-.--.. 0 4 0 0 Tr. 11 0 0 1 0 0 13 12 ...... 12 0 0

Ore in the Madera Limestone

254110. .- 

254109.- 

......... Agua Torres (0 ---------------

......... Marie (*)..... .......... .......

. ._ 0 3 0 0 12 7

......... 14 3 5 0 12 8

0

0

0

0

3

2

0

0

0

0

14

12

12 ......

11 ......

11

9

0

0

0

0

See footnotes at end of table.
114 URANIUM RESOURCES OP NORTHWESTERN NEW MEXICO

TABLE 6. Semiquantitative spectrographic, radiometric, and chemical analyses of mill pulp samples of uranium ores from limestone,

northwestern New Mexico Continued

Spectrographic * Continued

Eu F Fe Ga Gd Ge Hf Hg Ho In Ir K La Li Lu Mg Mn

Ore in the TodiHo Limestone

256424...........

256425............

256426...........

256427-.-.......

?29390.. .........

256428.. ..........

245228... ...... __

256429...........

256430...........

229393.. .........

?56431. ..........

256432.. .........

256433-. ._.......

256434...........

256435..........

256436.-------..

229391-...-..-..

256437 ..........

246891--..... .

256438 .......

256439--. --..

256440.-.....-..

229895.... .......

256441.. ........

256442 . 

229392.. ...... ..

256443 .

256444. 

229394. .. 

256445-.. _.___

256446- -

........ Barbara Jl (1).. ................

........ Billy The Kid (S).... ...........

..---. Black Hawk (4)... ..............

........ Bunney U) ..... 

... ..... Cedarl (fi)............ ..........

---... Christmas Day (6).... ..........

........ Crackpot (7)...... ......... .. ...

..-_... Flat Top 4 (If)..... .......... ...

........ Gay Eagle (IS). ........ ........

-. ...-- Hanosh (Section 26) (16). ......

........ Haystack2 (IT). ....... ...... ..

........ Last Chance (19) .... ...... .....

........ Red BluflS (&f> ....... ...

.. .... Red Bluff 5 (05) ... .........

... ..... Red Bluff 7 («ff)_... ....._.__...

.... .... . Red Bluff 8 (IS) ....... .........

.... -... Red Bluff 10 (/?) .........

......... Red Point Lode (88).........

..._., _ Reed Henderson. ..............

Rhnrnck (09)_ __

 ..... Section 18 (3«)_ ..............

.... .... . Sectioa 18 (S3) ...............

......... Section 19 (34) ...............

......... Section 21 (37)... ..............

......... Section 24 (39). .............

.... ..... Manol (Section 30) (tf). ........

......... Manol (Section 30, T-8) (*?)._..

._.--.-. Manol (Section 30, T-W) (**)..

... ...... TZ(4S). ......................

.-... . Tom Elkins (48)... ...........

......... UDC 5 (4ff). ..................

.. 0 .

.... 0 .

.... ... 0 .

. 0 .

....... ND

.... ... 0 .

 .. 0

 .... 0

....... ND

...... . 0

... . 0

....... 0

0

....... 0

....... 0

....... ND

..-.-. 0

-.. 0

.. ... 0

 ... 0

........ ND

._-_. 0

..--..- 0

........ ND

--...-- 0

 . . 0

........ ND

........ 0

 .... 0

....... 6000

...... 6000

....... 5000

....... 6000

ND 5 h 0 0

....... 6000

.... ..6000

....... 6000

....... 6000

ND 6 h 0 0

. ... 5000

... .... 6000

---... 5000

....... 6000

....--. 6000

....... 5000

ND 6 h 0 0

....... 6000

.... . 7000

....... 6000

...... . 6000

....... 5000

ND 7 h 0 0

....... 6000

-...-.- 6000

ND 6 h 0 0

....... 6000

...... . 6000

ND 6 h 0 0

....... 6000

 .... 6000

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0 0

0 0

0 0

0 0

0 ND

0 0

0 ......

0 0

0 0

0 ND

0 0

0 0

0 0

0 0

0 0

0 0

0 ND

0 0

0 ......

0 0

0 0

0 0

0 ND

0 0

0 0

0 ND

0 0

0 0

0 ND

0 0

0 0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

4

0

0

5

a

0

4

5

0

(5>

3

5

0

0

0

5

a

0

4

0

4

3

(8)

0

4

(5)

5

4

a

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0 0

0 0

0 0

0 0

0 ND

0 0

0 ......

0 0

C 0

C ND

0 0

0 0

0 0

0 0

0 0

0 0

0 ND

0 0

0 ......

0 0

0 0

0 0

0 ND

0 0

0 0

0 ND

0 0

0 0

0 ND

0 0

0 0

6

6

6

6

6

6

6

6

6

6

6

6

7

6

6

6

6

7

5

6

6

5

6

6

6

6

6

6

6

6

6

8

8

8

8

9

8

9

S

8

8

8

7

7

7

8

8

8

S

8

8

8

8

6

8

S

8

8

8

8

8

8

Ore in the Todilto Limestone and Entrada Sandstone

245229-.--.-.. ... ....... Sandy (7S). ................... ...... 5 Tr. 0 0 0 0 0 0 3 0 0 5 8

Ore in the San Andres Limestone

245227 .......... Lucky Don (1)..... .... ... ... ......... 5000 0 0 ...... 0 0 4 0 0 ...... 2

Ore in the Madera Limestone

254110.........

254109-.--...

........... Agua Torres (1) ............ ..

.......... Marie (S).. ...................

0 ....... 4 Tr. 0 0

0 .... 2 14 0 0

0

0

0 0

0 0

0

0

0

0

4

3

0

0

0 0

0 0

5

6

8

9

See footnotes at end of table.
DISTRIBUTION OF ELEMENTS IN THE ORES 1J5

TABLE 6. Semiquantitative spectrographic, radiomelric, and chemical analyses of mill pulp samples of uranium ores from limestone,

northwestern New Mexico Continued

Mo

Spectrographic * Continued

Na Nb Nd Ni Os P Pb Pd Pr Pt Rb Re Rh Ru Sb Sc

Ore in the Todilto Limestone

256424.. . 

256425 

256426 .....

256427 .

229390 - --

256428.-..

245228 -

256429 

256430-.-- __-

229393 - 

256431-.-..-.

256432__..- .-

256433- .-

256434-. . ......

256435 - -

256436 -

229391. 

256437_. ------

246891--. ------

256438-. ------

256439 - 

256440 -

229395 -.-_ _.

256441. .........

256442-. -

229392.. ...... ..

256443.. ...... ..

256444.- -

229394 

256445-.. -..

256446.. --.._-

-._-_-_-- Barbara Jl (1).... ...........

......... Billy The Kid (3) _ _..

------- Black Hawk U)..____._ ...

. __ -- Bunney (^. ................

......... Cedar 1 (6). .................

......... Christmas Day (S). .........

......... Crackpot (7). ...... ......

__---._._ Flat Top 4 (lg).... ..........

......... Gay Eagle (IS). .............

......... Hanosh (Section 26) (IB)....

. . ..... Haystack 2 (17). ....... ...

......... Last Chance (19)............

......... Red Blufl 3 W) --------

_.___..._ Red Blufl 5 (») ... .......

.._._.__. Red Blufl 7 (ge)... ..........

......... RedBluflS (IS)... ......... .

......... Red Bluff 10 (IS)... .........

-------- Red Point Lode (*8). .......

-___--_-. Reed Henderson- ...........

-.__--.-- Rimrock (gff)..... ...........

......... Section 18 (SS).. .............

 ..... Section 18 (S3). ..........

..__.- Section 19 (84). .............

--..-._-- Section 21 (S7)...... .........

......... Section 24 (39)...............

- ....... Hanoi (Section 30) (**)......

------ Hanoi (Section 30, T-8) (*«) .

------- Hanoi (Section 30, T-19) («*'

T 2 (46)

-------- TomElkins (48)............

......... UDC 5 (4»). ................

........... 13

........... 0

........... 14

.... .. 14

........... 14

. ..- 14

........... 0

.--....... 0

...... 14

.. ...- 12

........... 13

... ..... 0

..... 13

-------- 12

. ..--. 0

....... 14

__._ 13

...._.-.-- 0

-.. - 0

.- .__.- 0

........... 0

........... 0

........... f

.. ..... 0

.. ._ 0

..--...-- f

. _.-_..- 0

). ._-- 14

........... f

. ...- 0

........... 13

5

6

6

6

6

6

6

6

6

6

5

6

6

6

6

6

6

6

6

6

6

5

7

6

6

6

6

6

7

6

6

0 0 13 0

0 0 14 0

0 0 14 0

0 0 14 0

0 0 14 0

0 0 14 0

0 0 14 0

0 0 14 0

0 0 15 0

0 0 14 0

0 0 15 0

0 0 14 0

0 0 14 0

0 0 14 0

0 0 14 0

0 0 13 0

0 0 14 0

0 0 15 0

0 0 14 0

0 0 14 0

0 0 14 0

0 0 14 0

0 0 15 0

0 0 15 0

0 0 15 0

0 0 14 0

0 0 13 0

0 0 13 0

0 0 14 0

0 0 14 0

0 0 14 0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

11

1211

121111

12

11

11

10

11

11

11

11

11

11

11

12

14

13

11

12

13

13

11

11

11

10

13

12

11

0 0

0 0

0 0

0 0

0 ND

0 0

0 ......

0 0

0 0

0 ND

0 0

0 0

0 0

0 0

0 0

0 0

0 ND

0 0

0 ......

0 0

0 0

0 0

0 ND

0 0

0 0

0 ND

0 0

0 0

0 ND

0 0

0 0

0 ...

0 ......

0 ......

0 ......

0 ND

0 ......

0 ......

0 ......

0 ......

0 ND

0 ......

0 ......

0 ------

0 -...-.

0 ......

0 ......

0 ND

0

0 ......

0 -...-.

0 ......

0 ......

0 ND

0 ......

0 ......

0 ND

0 ......

0 ......

0 ND

0 ..... .

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0 0

0 0

0 0

0 0

0 f

0 0

0 0

0 0

0 0

0 f

0 0

0 0

0 0

0 0

0 0

0 0

0 f

0 0

0 0

0 0

0 0

0 0

0 f

0 0

0 0

0 f

0 0

0 0

0 f

0 0

0 0

Ore in the Todilto Limestone and Entrada Sandstone

245229 -

245227 - .

......... Sandy (76)... ...............

-------- Lucky Don (1) .... ..........

........... 13

Ore

........... 13

4 0 0 14 0 0 12 0 ...... 0 ...... 0 0 0 0 0

in the San Andres Limestone

6

Ore in the

254110--- -

254109 

......... Agua Torres (I)... ..........

......... Harie (*) ... . .

........... 12

........... 10

7

6

0 0 11 0

Madera Limestone

0 0 12 0

0 0 12 0

0

0

0

11

12

5

0 ......

0 0

0 0

0 ......

0 ......

0

0

0

0

0

0

0

0

0

0

0 0

0 14

10 14

See footnotes at end of table.
116 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

TABLE 6. Semdquantitative spectrographic, radiometric, and chemical analyses of mill pulp samples of uranium ores from limestone,

northwestern New Mexico Continued

Si Sn Sr S

Spectrographic 2 Continued

im Ta Tb Te

Ore in the Todttto

256424.. ._.._.__

256425.. ... _____

256426__._... ...

256427-. ____._..

229390,-. ... ____

256428__. .... ...

245228-. .____

256429,_______._

256430-_______-_

229393. _________

256431

256432. _____-.__

256433- ..---___

256434. -_.--____

256435-. -.---_-_

256436-______.__

229391- _ ________

256437--. _______

246891--. _______

256438-. _____--.

256439-. ..... ___

256440.. .___-__.

229395-- - 

256441__. ____.-_

256442_____---_

229392 __-__.--

256443.. .......

256444____._-___

229394_. ________

256445.. ..--.-

256446____-_--

_ ..... Barbara J 1(1). ...... .........

____ .. Billy The Kid (S)-. ...........

_______ Black Hawk «)........ .

.. . . Bunney U)^. ............. ... .

......... Cedarl (S). ....... ...........

......... Christmas Day (S)... .........

......... Crackpot (7) .................

......... Flat Top 4 (/*). -..... ..

._.._____ Gay Eagle (;5)-- ---------

........ Hanosh (Section 26) (16)......

_________ Haystack 2 (17).... ..........

......... Last Chance (19)..............

......... Reb Blufi 3 (24) ---------

________ Reb Bluff 5 (86).... .._...____.

... _____ RedBlufl 7 (26). ........ ......

___ __._. Red Blufi 8 (IS). .............

... ..... Red Bluff 10 (IS)... .........

......... Red Point Lode (H8). .........

... ... Reed Henderson. . .. . _____

..__._._. Rimrock (S9). .................

......... Section 18 (St)..... ............

... ..... Section 18 (SS).... .............

... ..... Section 19 (34)___.__. _____.___.

.__ _____ Section 21 (S7). ................

......... Section 24 (39).. ..............

......... Manol (Section 30) (22)........

.. _____ Manol (Section 30, T-8) (22)...

... ..... Manol (Section 30, T-19) («.?) _.

____...__ T 2 (45).. .....................

_. Tom Elkins (48). ._____-_.___.

.-. ..___ VDC 5(49). ..................

 _-- 109

-____-- 308

-..._-- 209

...209

3 0 10

--_ -. 309

.____._.. 309

......... 209

309

.____.___ 7 0 10

..... . 1 0 10

...2 09

_______ 309

.-.______ 208

____.-__ 209

.... .... 108

3 0 10

....309

3 0 9

......... 308

108

....109

-__40 10

. .--. 308

.-_-.-_ 109

.--___- 3 0 10

.. -. 109

.. . -. 1 0 9

-__..___ 3 0 10

 .__. 308

2 0 9

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Limestone

000

000

000

000

0 ND 0

000

0 ...... 0

000

000

0 ND 0

000

000

000

000

000

000

0 ND 0

000

0 ...... 0

000

000

000

0 ND 0

000

000

0 ND 0

000

000

0 ND 0

000

000

Th Ti

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

8

9

8

8

9

9

11

8

9

8

8

9

10

9

9

8

9

8

9

9

9

8

10

9

8

9

8

8

10

9

8

Tl Tm

0 0

0 0

0 0

0 0

0 ND

0 0

0 ......

0 0

0 0

0 ND

0 0

0 0

0 0

0 0

0 0

0 0

0 ND

0 0

0 ______

0 0

0 0

0 0

0 ND

0 0

0 0

0 ND

0 0

0 0

0 ND

0 0

0 0

TI

6

8

7

8

6

7

8

7

7

6

7

7

7

7

7

7

7

8

0

8

7

8

7

7

7

6

7

6

7

7

7

V

9

7

9

8

9

8

7

8

8

8

9

7

10

9

8

7

8

8

8

7

7

7

7

7

8

7

8

9

7

7

8

W

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

r

14

0

Tr.

0

0

0

0

0

0

14

0

0

0

0

0

0

0

0

0

0

0

14

0

0

0

0

0

Tr.

0

0

0

Yb Zn

d

d

d

d

h

d

e

d

d

f

d

d

0

0

d

d

f

d

d

d

d

f

d

d

f

d

d

f

d

d

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Zr

11

12

11

12

12

to

12

11

11

11

10

12

13

12

12

11

12

12

12

11

11

11

13

13

10

12

12

11

12

12

12

Ore in the Todilto Limestone and Entrada Sandstone

245229.. __... ...

245227. .... .

......... Sandy (76).--.-.-....-......

-_._..__- Lucky Don U) _ -- ----------

..... ... 1 0 10

Ore in the San

... .-. 1 0 11

0 0 0 0 8 0 8 9 0 13 15 0 11

Andres Limestone

0

Ore in the Madera

254110

254109 -. 

_-_ -_ Agua Torres (/) .......... _ .

.... . Marie (a).-..... ..........

-107

. . .. 1 0 9

0

0

0 0

Limestone

000

000

0

0

0

8

7

6

0

0 0

10 0

7

8

7

7

9

9

0

ND

ND

0

13

13

e

15

15

7

9

7

11

11

10

See footnotes at end of table.
DISTRIBUTION OF ELEMENTS IN THE ORES J17

TABLE 6. Semiquantitative spectrographic, radiometric, and chemical analyses of mill pulp samples of uranium ores from limestone,

northwestern New Mexico Continued

Radiometric

eU 3 U* V2 (V

Percent

S6

Chemical

P2 05 1 C « 

(organic)

As » Fi. Se» Zni*

Parts per million

Ore in the Todilto Limestone

256424.. .

256425 

256426. 

256427---.-...

229390...-._._.

256428-. ... .....

245228 .

256429 

256430 _ 

229393_._--. _

256431- 

256432 

256433-. -------

256434---.--.

256435- 

256436 

229391--------.

256437 

246891 . 

256438 . 

256439 .

256440 -

229395 - 

256441 - 

256442 

229392-------.

256443 -

256444.-.---.--.

229394- .-__.. ..

256445-. -------

256446-.---....

245229 

-. .. Barbara Jl (1).. .............

--.._-. BillyTheKid(S)-_ ... .

 Black Hawk (4)___

-------- Bunney (4)---.. ......

. .__.- Cedar 1 (5)... ................

-___-_._. Christmas Day (6). ..........

......... Crackpot (7). __. ... _.

-.--____. Flat Top 4 (lg). ........

......... Gay Eagle (IS)................

......... Hanosh (Section 26) (IS).....

..... ... Haystack2a7) .

_-_-____- Last Chance (19)..

Red Bluff 3 (#4)

___._-___ RedBluff 5 (gS)...... .........

......... RedBluff 7 (g6)... ............

......... RedBluff 8 (13). . . .

......... RedBluff 10 (IS)..............

......... Red Point Lode (#«) _...

----_____ Reed Henderson ........... .

Rimrock (#9). . -...

----__... Section 18 (Sg)...... ...........

......... Section 18 (SS)...... ...........

----_____ Section 19 (34) ............

----_-_.. Section 21 (37) ------------

------- Section 24 (S9).................

......... Manol (Section 30) (SS). .......

------- Manol (S ection 30, T-8) (gg) . . .

......... Manol (Section 30, T-19) (M)..

......... T2(4S). ......................

......... Tom Elkins (48)..............

.-_-____- UDC 5 (49)............ 

Ore

__- .. Sandy (7fi)... .................

-------- 0.23

.... .09

 ..... .12

-..-._- .08

---____- .21

.--__-_ .16

.--_____ .07

.-__. . .19

.--.. _ .16

----____- .31

------- .15

.--____. .12

.--._-___ .17

---____. .16

-------- .13

---.._-. .13

.----.__. .17

. _____ .11

.... ..... .03

--_____ .10

--._._. .15

.--_____ .10

---._._- .14

._-_____ .10

-------- .19

.... . . .19

.__--____ .17

...... .- .28

---__-.. .12

----_._ .12

------ .14

0.23

.09

.12

.08

.24 ..

.16

.10

.20

.18

.34 ._

.16

.13

.16

.16

.13

.14

.18 ...

.11

.03

.11

.16

.10

.14 ....

.11

.18

.23 _-

.19

.31

.13 ___

.11

.14

0.09

.30

.08

.11

.13

.33

.13

.15

.13

.23

.05

.05

.09

.14

.07

.12

.28

.33

.23

.30

.15

.11

.07

.19

.06

0.07

.03

.04

.03

.04

.11

.03

.03

.08

.03

.04

.03

.04

.03

.03

.05

.03

.03

.03

.03

.03

.04

.04

.04

.04

0.026

.003

.015

.003

.024 _..

.003

.011 .-.

.003

.003

.031 -_.

.015

.003

.015

.018

.003

.003

.017 ....

.005

.015

.003

.003

.003

.004 ....

.003

.003

.019 ....

.007

.029

.004 ....

.003

.011

0.11

.08

.07

.08

.10

.09

.06

.14

.06

.05

.06

.07

.08

.06

.92

.06

.06

.07

.06

.06

.12

.10

.06

.06

16

3

23

11

60

18

18

18

20

50

8

6

33

21

12

19

60

20

8

8

9

8

10

2

2

50

19

16

10

4

29

50

50

340

30

290

290

160

630

190

1,700

60

50

90

90

120

150

440

30

80

110

20

20

160

20

20

460

240

130

130

20

370

5

1

3

2

5

4

3

3

4

5

8

2

4

3

2

3

5

3

.5

3

5

4

5

2

1

2

3

3

1

3

5

20

10

10

10

20

10

7

10

10

20

10

10

10

10

10

10

10

10

4

10

20

10

10

10

30

10

10

10

20

10

10

in the Todilto Limestone Limestone and Entrada Sandstone

.--__._. 0.09 0.10 0.13 0.08 0.024 15 60 15 12

Ore in the San Andres Limestone

245227..-.--..

254110 .

254109- 

---._____ Lucky Don (/)_.. 

________ Agua Torres (1).. .............

-_--. -. Marie (#)-_._ ............

-_-.-.- 0.17

Ore in the

---_____ 0.06

------ .17

0.22

Madera

0.08

.17

0.43

Limestone

0.11

.05

0.06

0.46 ..

3.27

0.011 41

172 ..

6,200

240

890

10

50

75

830

37

2,100

1 Spectrographic analyses, chemical analyses for As, Se, TJ, and Zn, and radiometric 

analyses for TJ for samples 229390-229395 inclusive requested by A. T. Miesch.

2 Analysis of sample 246891 by N. M. Conklin; all others by R. G. Havens.

3 Analysts: C. G. Angelo, R. P. Cox, G. S. Erickson, Mary Finch, W. D. Goss, 

H. H. Lipp, T. Miller, and J. S. Wahlberg.

4 Analysts: C. G. Angelo, R. P. Cox, E. J. Fennelly, D. L. Ferguson, Mary Finch, 

W. D. Goss, H. H. Lipp, T. Miller and J. S. Wahlberg. Fluorimetric method. 

s Analysts: W. D. Goss, H. H. Lipp, and J. S. Wahlberg. Volumetric method. 

6 Analysts: G. T. Burrow, D.L. Ferguson, and E. C.Mallory. Gravimetric method.

J Analysts: D. L. Ferguson and L. F. Rader, Jr. Volumetric method. 

8 Analysts: Wayne Mountjoy and J. P. Schuch. Rapid scanning, CO2 method1 . 

»Analysts: R. R. Beins, H. E. Crowe, E. J. Fennelly, Claude Huffman, J. P. 

Schuch, and J. E. Wilson. Colorimetric method.

10 Analysts: R. P. Cox, W. D. Goss, and L. F. Rader, Jr. Colorimetric method.

11 Analysts: C. G. Angelo, G. T. Burrow, R. P. Cox, Mary Finch, W. D. Goss, 

H. H. Lipp, T. Miller, and J. S. Wahlberg. Colorimetric method.

12 Analysts: R. R. Beins, G. T. Burrow, and H. E. Crowe. Colorimetric method
118 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

ORE SAMPLE GROUPS AND THEIR CHARACTERISTICS

Tables 5 and 6 indicate that the ores are generally 

in radioactive equilibrium and, with the exception of the 

Woodrow, are of about the same grade; tables 7-9 reveal, however, some differences that can be related to 

the stratigraphic position, to rock type, and to tectonic 

structure, but areal differences within stratigraphic 

units generally are not notable. The various differences, 

plus what is known of the geology of the deposits, support the following twofold classification of the ore 

groups, listed by stratigraphic host unit:

Class 1 ore sample groups 

Baca Formation 

Dakota Sandstone

Class 2 ore sample groups 

Espinaso Volcanics of Stearns 

(1943)

Classl ore sample groups 

Dakota Sandstone (shale) 

Morrison Formation 

Todilto Limestone

Class % ore sample groups 

Popotosa Formation 

Morrison Formation (Woodrow 

deposit)

Todilto Limestone and Entrada San Andres Limestone

Sandstone Madera Limestone 

Cutler Formation

A discussion of these ore sample groups and their 

geologic relations must be prefaced by an understanding of the inherent limitations of the asray methods, 

especially for the spectrographic data, and of the nearthreshold quantities and the varying limits of detection among different samples. For these reasons it is 

assumed that differences between means generally are 

not significant unless they differ by at least a factor

TABLE 7. Ranges of concentration and the geometric means of eight major elements in 12 sample groups of tlie uranium ores,

northwestern New Meaftoo

[All analyses are spectrographic]

Ore sample groups

(By formation, type of

host rock [ ] , and 

distinctive structure*)

Espinaso Volcanics of 

Stearns (1943) [ « ]*

Popotosa Formation [ O ]*

Baca Formation [ O ]

Dakota Sandstone [ 9 ]

Dakota Sandstone

(shale) [ o ]

Morrison Formation [ ]

Morrison Formation

(Woodrow deposit) [ ]*

Todilto Limestone [A ]*

Todilto Limestone and

Entrada Sandstone [ A ]

Cutler Formation [ e ]

San Andres Limestone [ V ]*

Madera Limestone [ A ]*

Espinaso Volcanics of

Stearns (1943) [ « ]*

Popotosa Formation [ O ]*

Baca Formation [ O ]

Dakota Sandstone [ 9 ]

Dakota Sandstone

(shale) [ » ]

Morrison Formation [ ]

Morrison Formation

(Woodrow deposit) [ ]*

Todilto Limestone [A ]*

Todilto Limestone and

Entrada Sandstone [ A ] "

Cutler Formation [ e ]

San Andres Limestone [ V ]*

Madera Limestone [ A ]*

 M 8

°t

O g

2

2

1

5

1

218

1

31

1

33

1

2

2

2

1

5

1

18

1

31

1

3

1

2

Percent

SSSB2 m ^u, °

OOOOOOO^OOr*./^

1 1 1 1 1 1 1 1 1 1 1

ALUMINUM (Al)i

+

1

1 H1

 | 

1

 I 

1 +-

1

1

IRON (Fe)

-I 

+

1

 1 

1

_j 

1

 \ 

1 4-

1

, , , , ,~t~; ,

« 

°'H

II

CO

2

2

1

5

1

18

1

31

1

3

1

2

2

2

1

5

1

18

1

31

1

33

1

2

Percent

o « m r*. in o

OOOOOOO-*POr*./\

1 1 1 1 1 1 1 1 1 1 1 MAGNESIUM (Mg)

4

4-

1

4-

1

 | 

1

 1 

1

4-

1

4-

CALCIUM (Ca)l

-4

 | 

1 H 

1

 I 

1

1

1 H1

r-

*m

Oro,

IICO

2

2

1

5 (1)

1

18

1

31

1

3

1

2

2

2

1

5 (2)

1

18

1

31(15)

1

3

1

2

Percent

SSSSiSn^u, S

oooo o oo«-Joo ^-/\

1 1 1 1 1 1 1 1 1 1 1 SODIUM (Na)

+

 i 

\

- 1 

1

 \-

\

 \ 

1

1

1 4-

POTASSIUM (K)

4-

1

1

+-

1H1

-H 

1

1

1

4-

 sJs

II

2

2

1

5

1

18

1

31

1

3

1

2

2

2

1

5

1

18

1

31

1

3

1

2

Percent

SSSSSn^u, 2

OOOOOOO^TOI^/^

1 1 1 1 1 1 1 1 1 1 1 TITANIUM (Ti)

4

4

1

4

1 H1

 h

1

4

1

4

MANGANESE (Mn)

4

4

1 H 

1

 1 

1

 h

1

1

1

i i ii i i i i i i i

1 Samples reported as >10 are assumed to be 15, which is the next 

higher number in the series 1.5, 3, 7, etc.

2 Includes 3 samples reported as >10.

3 Includes 1 sample reported as >10.

4 Number in parentheses is the number of samples below the limit 

of detection.

EXPLANATION

H* Range in content of samples *H 

Dashed where uncertain | I

Geometric mean of all samples 

in which element detected

Ore sample groups

[ 9 ]* Tertiary igneous breccia; in footwall

of igneous dike 

[ O ]* Tertiary sandstone; in hanging wall

of low-angle fault 

[ O ] Tertiary sandstone 

[ 9 ] Cretaceous sandstone 

[ « ] Cretaceous shale

[ ] Jurassic sandstone

[ ]* Jurassic sandstone (Woodrow deposit);

in near-vertical breccia pfpe 

[A ] * Jurassic limestone 

[ A ] * Jurassic limestone and sandstone 

[ e ] Permian sandstone 

[ v ]* Permian limestone; in footv^all of

high-angle fault 

[ A ]* Pennsylvanian limestone; in footwall

of high-angle fault
DISTRIBUTION OF ELEMENTS IN THE ORES 119

of 2. The above classification, therefore, as far as elemental assem'bladges are concerned, is restricted to 

about 20 of the approximately 70 elements detected. 

With this in mind, the assemblages in the ores and 

the geology of the respective deposits yield the following characteristics of each class of ore sample groups.

Characteristics of the ore sample groups

Class 1 groups 

1. Similar elemental assemClass $ groups 

1. Diverse elemental assem2. Similar mineralogy _______

3. Similar and rather mild 

alteration effects.

4. Occurrence in sedimentary 

rocks.

5. Peneconcordance_________

6. Generally not directly

related to tectonic structures, except to intraformational structures.

7. Wide stratigraphic and

areal distribution, principally in the Colorado 

Plateaus and Rocky 

Mountains provinces.

2. Diverse mineralogy.

3. Diverse and generally

more intense alteration 

effects.

4. Occurrence in sedimentary 

and igneous rocks.

5. Generally veinlike.

6. Direct relationship to 

fractures.

7. Wide stratigraphic but

rather limited areal distribution, principally in 

the Rio Grande trough, 

of the Basin and Range 

province.

Class 1 includes most of the ore samples from deposits of the so-called sandstone or peneconcordant 

type (Finch, 1959). Class 2 includes ore samples that 

generally have a relatively high content of various 

base and ferrous metals and of sulfur, arsenic, fluorine, 

and thallium (in two samples); all ores are from deposits that are closely associated with faults and from 

host rocks that generally are sheared or brecciated.

Some deposits which do not quite fit these criteria 

or which are somewhat exceptional are discussed below 

under their respective groups.

EXCEPTIONAL CHARACTERISTICS OF SOME ORE 

SAMPLE GROUPS

ESPINASO VOLCANICS OF STEARNS (1943)

Most distinctive of the ore sample groups is that in 

the Espinaso Volcanics of Stearns (1943) because of its 

exceptional assemblage of elements a relatively high 

content of iron (table 7), silver, cerium, cobalt, chromium, copper, germanium, molybdenum, nickel, strontium, lanthanum, and neodymium (tables 5, 8), arsenic, 

fluorine, and sulfur (table 9) and 'a relatively low content of vanadium and selenium (table 9). The strontium 

and germanium, and possibly the lanthanum and neodymium, may in large part be original constituents of 

the host rock. The rest of the assemblage, especially 

iron, silver, cobalt, chromium, copper, nickel, arsenic 

fluorine, and sulfur, probably was introduced during the 

ore-forming process and is strikingly more abundant 

than in the groups of class 1, and the first, six of these 

elements generally are more abundant than in the other

groups of class 2, except for the group in the Woodrow 

deposit. The geometric means of these elements in the 

Espinaso range from about 3 times to more than 10 

times those in any of the groups of class 1, as shc^n 

in summary table 10. The opposite is true for vanadium, which is quite low and generally less thai in 

each of the groups of class 1, except for the group in 

the shale of the Dakota Sandstone. The low vanadium 

content in the Espinaso is what would be expectec1 in 

a sulfide-rich deposit of magmatic affinities (Gc^dschmidt, 1954, p. 490).

Deposits in the Espinaso Volcanics are within $md 

along the side of a near-vertical mafic dike in sulf demineral veinlets and in a hydrothermally altered, 

sulfide mineral-impregnated clayey matrix (table 4). 

The locality is the west side of the Los Cerrillos mining district, an area that is characterized by basemetal vein deposits. Although the mineralogy of the 

deposits in the Espinaso is incompletely known, the 

assemblage of elements and general structural relations of the deposits indicate that they are related1 to 

the other base-metal deposits of the Los Cerrillos

district.

POPOTOSA FORMATION

Classification of the group in the Popotosa Formation and of some of the other groups in class 2 is less 

certain because some of them, and the deposits they 

represent, have characteristics of both classes.

Table 10 shows that the group generally is appreciably higher in aluminum, cobalt, copper, nickel 

fluorine, and zinc (with some single exceptions) than 

are the ores in the groups of class 1. The aluminum 

content may not be meaningful, as it could represent in 

large part the original host rock or fault gouge and 

not have been introduced with the ore. The concentrations of the other elements may partly be related to 

the occurence of the deposit in the Popotosa in the 

hanging wall of the Cerro Colorado fault, a fault that 

bounds the west side of the Eio Grande trough 

(Denny, 1940, fig. 1; Kelley 'and Wood, 1946), and 

partly to the association of the ore with what may be 

hydrothermally altered rocks. Clay, which apparertly 

occurs only locally in beds in the Popotosa (Denny, 

1940), is a principal constituent of the ore. Much of 

the clay could be gouge, an attrition product of faulting, but a several-foot-thick bed of dark-gray clay 

occurs at the outcrop of the ore body and is interbedded 

with tuffaceous sandstone. Because the sandstone, is 

bleached but the bedding not visibly disturbed or 

broken, the clay may be a hydrothermal product.
120 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

TABLE 8. Ranges of the geometric means of 19 minor elements in 12 sample groups of the uranium ores, northwestern New

Mexico

[All analyses are spectrographic. Numbers in parentheses are samples below limit of detection]

Ore sample groups

(By formation, type of

host rock [ ] , and 

distinctive structure*)

Espinaso Volcanics of

Stearns (1943) [ ® ]*

Popotosa Formation [ O ]*

Baca Formation [ O ]

Dakota Sandstone [ » ]

Dakota Sandstone

(shale) [ > ]

Morrison Formation [ ] 

Morrison Formation

(Woodrow deposit) [ ]*

Todilto Limestone [A ] *

Todilto Limestone and

Entrada Sandstone [ A ] *

Cutler Formation [ 9 ]

San Andres Limestone [ V ]*

Madera Limestone [ A ]*

Espinaso Volcanics of

Stearns (1943) [ ® ]*

Popotosa Formation [ O ]*

Baca Formation [ O ]

Dakota Sandstone [ » ]

Dakota Sandstone

(shale) [ o ]

Morrison Formation [ ]

Morrison Formation

(Woodrow deposit) [ ]*

Todilto Limestone [ A ]*

Todilto Limestone and

Entrada Sandstone [ A* ]*

Cutler Formation [ * ]

San Andres Limestone [ V ]*

Madera Limestone [ A ]*

Espinaso Volcanics of

Stearns (1943) [ ® ]*

Popotosa Formation f O ]*

Baca Formation [ O ]

Dakota Sandstone [ » ]

Dakota Sandstone

(shale) [ » ]

Morrison Formation [ ]

Morrison Formation

(Woodrow deposit) [ ]*

Todilto Limestone [ A ]*

Todilto Limestone and

Entrada Sandstone [ A ] *

Cutler Formation [ 9 ]

San Andres Limestone [ V ]*

Madera Limestone [ A ]*

Espinaso Volcanics of

Stearns (1943) [ e ]*

Popotosa Formation [ O ]*

Baca Formation [ o ]

Dakota Sandstone [ 9 ]

Dakota Sandstone

(shale) [ « ]

Morrison Formation [ ]

Morrison Formation

(Woodrow deposit) [ ]*

Todilto Limestone [ A ]*

Todilto Limestone and

Entrada Sandstone [ A» ]*

Cutler Formation [ » ]

San Andres Limestone [ V ]*

Madera Limestone. [ A ]*

<4H CU

|f

2

2 (1)

I

5 (5)

1 (1)

18 (18)

i

131(30)

1 (1)

3 (1)

1 (1)

2 (1)

2 (2)

22 (1)

2 1 ID

5 (1)

1

18 (6)

1 (1)

31(31)

3 1 (1)

3

3 1 U)

2

2

2

1

5

1

18

1

31

1

O

1

2

2 (2)

2

1

5 (5)

1

18 (5)

41

31(31)

1 (1)

3

1 (1)

2 (2)

Percent

£ m t~- in

iiililligSSBS^in

OOOOOOOOOOOOOOOi^ 1 1 1 1 1 1, 1 1 1 1 1 1 1 1 1

SILVER <Ag)

 | 

-1

1

-O

-O

-o

1

 1

 o

 1

-o

 1

BORON (B)

-O -O

 1

 o

- +

1

 1-

 o

 o o

1

.j 

1

1

BARIUM (Ba)

-j-

-j1 4-

1

1

 | 

1

4-

1

+

BERYLLIUM (Be)

-O

1

1

 O

1 h

1

 o

 o

 1 

-o

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

<4H CD °-ft

z i

2

2

1

5

1

18 (1)

1

31 (4)

1

3

1

2

2

2

1

5

1

IBlo

i

31

1

3

1

2

2

2

1

5

1

18

1

31

1

Q

1

2

52

2

1

5 (5)

1

618 (5)

U

31 (31)

n

3

1 U)

82

Percent

!2 m r- m

liiiilsiissBSn^^ ooooooooooooooo < 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

COBALT (Co)

-[-

-(-

1

-1-

1

~~"

1 -h

1

4-

1 1 

CHROMIUM (Cr)

1

1

1

 \-

\

|

1

 1 

1

-h

1HCOPPER (Cu)

1

+

1

 | 

V

1

-\-

1 1 

1 -4 

GALLIUM (Ga)

1

1

1

-O

1

- |-

1

-O

1 1 

 o

1 1 1 1 I 1 1 1 1 1 1 1 1 1 1 1 1

.

5S"2_

11

2

2

1 U)

5 (4)

1

18(16)

1 ID

31(31)

1 (1)

3

1 ID

2 (2)

2

2

1

5 (1)

1

18 (1)

1

31(17)

1

3 (1)

1

2

2

2

1 (1)

5 (4)

1 (1)

18(12)

1 (1)

31(31)

1 (1)

3 (2\

i (i)

2 (2)

92

2 (2)

1 (1)

5 (5)

1 (1)

18(17)

1 HI

31(31)

1 d>

93 (1)

1 (1)

2 (2)

Percent

12 m t- in

ilili!ll§3SB:2 m ^,n OOOOOOOOOO'OOOO'O^H

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

LANTHANUM (La)

1

1

 O

 1

1 r»

-o

-o

-o

-I-

-o

-o

MOLYBDENUM (Mo)

 1 

1

1

-H 

1

 1 

1

 1 

1

 | 

1

-tNIOBIUM (Nb)

1

-|-

-O

_ ___ i

-O

 1

-o

 o

 o

 1

 o

 o

NEODYMIUM (Nd)

4-

-O

-0

-0

-o

 1

-o

 o

-o

 1-

-o

 o

1 1 1 1 1 1 I 1 1 1 1 1 1 1 1

1 One sample reported as trace, assumed to be 0.00005.

2 One sample reported as 0.001.

3 One sample reported as trace, assumed to be 0.002.

4 Sample reported as trace, assumed to be 0.0001.

5 Both samples reported as trace and assumed to be 0.0002.

6 Includes 2 samples reported as trace and assumed to be 0.0002.

7 Sample reported as trace, assumed to be 0.0002.

8 Includes 1 sample reported as trace and assumed to be 0,0002.

9 Includes 1 sample reported as trace and assumed to be 0.01.
DISTRIBUTION OF ELEMENTS IN THE ORES 121

TABLE 8. Ranges of the geometric means of 19 minor elements in 12 sample groups of the uranium ores, northwestern 2 rew

Mexico Continued

Ore sample groups

( By formation, type of

host rock [ ] , and 

distinctive structure*)

Espinaso Volcanics of

Stearns (1943) t ® ]*

Popotosa Formation [ O ]*

Baca Formation [ O ]

Dakota Sandstone [ a ]

Dakota Sandstone

(shale) [ » ]

Morrison Formation [ ]

Morrison Formation

(Woodrow deposit) [ Y

Todilto Limestone [A ]'

Todilto Limestone and

Entrada Sandstone [ A« ]*

Cutler Formation [ » ]

San Andres Limestone [V ]*

Madera Limestone [A ]*

Espinaso Volcanics of

Stearns (1943) [ ® ]*

Popotosa Formation [ O ]*

Baca Formation [ O ]

Dakota Sandstone [ a ]

Dakota Sandstone

(shale) [ » ]

Morrison Formation [ * ]

Morrison Formation

1 Woodrow deposit) [ ]*

Todilto Limestone [A ]*

Todilto Limestone and

Entrada Sandstone [A* ]*

Cutler Formation [ e ]

San Andres Limestone [ V ]* 

Madera Limestone [ A ]*

Espinaso Volcanics of

Stearns (1943) [ ffi ]*

Popotosa Formation [ O J*

Baca Formation [ O ]

Dakota Sandstone [ a ]

Dakota Sandstone

(shale) [ « 1

Morrison Formation [ ]

Morrison Formation

(Woodrow deposit) [ J*

Todilto Limestone [ A ]*

Todilto Limestone and

Entrada Sandstone [ A* ] 4

Cutler Formation f e ]

San Andres Limestone [ V ]*

Madera Limestone [ A ]*

Espinaso Volcanics of

Stearns (1943) [ ffi ]*

Popotosa Formation [ O ]*

Baca Formation [ O ]

Dakota Sandstone [ a ]

Dakota Sandstone

(shale) [ » ]

Morrison Formation [ J

Morrison Formation

(Woodrow deposit) [ ]*

Todilto Limestone [ A ]*

Todilto Limestone and

Entrada Sandstone [ A« ]~

Cutler Formation [ 9 ]

San Andres Limestone [ V ]*

Madera Limestone [ A ]*

°t

o a 

*l

2

2

1

5

1

18

1

31

1

3

1

2

2

2

1

5 (2)

1

18

1

31

1

3

1

"

2

2

1

5 (3)

1

18(12)

1

31(31)

1 (1)

3

1 ID

2

2

2

1

5

1

18

1

31

1

3

1

2

Percent

S2 m r~ 10

pOpoOOOOOppO'-irnr~~Ln

ooo'oooooooooooo^

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 NICKEL (Ni)

 1 

+

1

+-

1

 | 

1

 | 

1

+

1

1

LEAD (Pb)

1

 | 

1

1 ____

1

 | 

1

 | 

1 

 1 

SCANDIUM (Sc)

+

+

1

 h

1

 \-

1

-O -O

-o -f-

 o

1

STRONTIUM (Sr)

+

 | 

1

 1 

1

1

1

-h

1

1 1 1 1 1 1 1 1 I 1 1 1 1 1 1

"o--- o'S

55 1

2

2

1

5

1

18 (2)

1

1031(26)

1

3

1 (1)

2

2

2 (1)

1 (1)

5 (5)

1

17(171

1 ID

30(30)

1

3 (2)

1 (1)

2

2

2

1

5

1

18

1

31

1

3

1

2

Percent

2 m i^ m

oooooooooooo^mr^m

ooooooooooooooo~* 

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 YTTRIUM (Y)

1

1

1

-H

1

- 1 

1

--- h

1

+

-o

1

YTTERBIUM (Yb)

1

 1

-O

-O

1

 O

-o

-o -o

1

1

-o

1

ZIRCONIUM (Zrl

1

+

1

 | 

1 H 

1

 1 

1

-f1+

i i i i i * i i i i i i i i i

EXPLANATION

"Range in content of samples 

Dashed where uncertain

Geometric mean of all samples reported as 

trace or more. Questioned where doubtful

Approximate limit of sensitivity where the 

element is undetected in all samples

 O -O

Approximate limits of. sensitivities where 

they vary between samples. All sample? 

undetected and below either or both 

limits

Ore sample groups

$ ]* Tertiary igneous breccia; in footwall

of igneous dike 

O ]* Tertiary sandstone; in hanging wall

of low-angle fault 

O ] Tertiary sandstone 

a ] Cretaceous sandstone 

« ] Cretaceous shale

 ] Jurassic sandstone

 ]* Jurassic sandstone I Woodrow deposit);

in near-vertical breccia pipe 

A ]* Jurassic limestone 

A ] * Jurassic limestone and sandstone 

8 ] Permian sandstone 

V ]* Permian limestone; in footwall of

high-angle fault 

A ]* Pennsylvanian limestone; in footwall

of high-angle fault

10 Includes 2 samples reported as trace and assumed to be 0.001.
122 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

TABLE 9. Ranges of concentration and, the geometric means of uranium, vanadium pentoxide, sulfur, phosphate, organic 

carbon, arsenic, fluorine, selenium, and zinc in 12 sample groups of the uranium, ores, northwestern New Mexico

[Analyses are chemical except for some samples of V2O5 . Where no chemical analyses are available or show an assay of <0.10 peremt VaOs. spectrographic analyses are used by conversion of V to VgOg. ]

Ore sample groups 

( By formation, type of 

host rock [ ] , and 

distinctive structure*)

Espinaso Volcanics of 

Stearns (1943) [ ® ]* 

Popotosa Formation [ O ]* 

Baca Formation [ O ] 

Dakota Sandstone [ ] 

Dakota Sandstone 

(shale) [ » ]

Morrison Formation 

(Woodrow deposit) [ ]*

Todilto Limestone and 

Entrada Sandstone [ A* ]* 

Cutler Formation [ 9 ] 

San Andres Limestone [ V ]* 

Madera Limestone [ A ]*

Espinaso Volcanics of 

Stearns (1943) [ ® ]* 

Popotosa Formation [ O ]* 

Baca Formation [ o ]

Dakota Sandstone 

(shale) [ » ]

Morrison Formation 

(Woodrow deposit) [ ]*

Todilto Limestone and 

Entrada Sandstone [ A* ]* 

Cutler Formation [ e ] 

San Andres Limestone [ V ]* 

Madera Limestone [A ]*

Espinaso Volcanics of

Popotosa Formation [ O ]* 

Baca Formation [ O ] 

Dakota Sandstone [ O ] 

Dakota Sandstone 

(shale) [ <» ]

Morrison Formation 

(Woodrow deposit) [ ]*"

Todilto Limestone and 

Entrada Sandstone [ AC ] * 

Cutler Formation [ e ] 

San Andres Limestone [ V ]*

Espinaso Volcanics of 

Stearns (1943) [ ® ]* 

Popotosa Formation [ O ]* 

Baca Formation [ O ] 

Dakota Sandstone [ O ] 

Dakota Sandstone 

(shale) [ « ] 

Morrison Formation [ ] 

Morrison Formation 

(Woodrow deposit) [ ]*

Todilto Limestone and 

Entrada Sandstone [AC]* 

Cutler Formation [ e ] 

San Andres Limestone [ V ]* 

Madera Limestone [ A ]*

If

2 

2 

1 

5

1

18

i

i

3 

1 

2

2 

2

1

1

1

1 

3

1 

2

1 

0 

1

0

1

1 

1 

1

2

0

1 

0

1

0 

18(3)

0

0 

0 

0 

0

Percent

p ^ in p op 

. 1 , , , i 1 , ,,!,,,,! , . . 1 . . , . 1

URANIUM (U)

H1

1

 1 

1

 I 

1 

1

VANADIUM PENTOXIDE (V2 O5 )

1 

1

1

1

1 ____ 

1

SULFUR (S)

1

No data 

1

No data

 | 

1 

 1 

1 

1 

1 

 1 

ORGANIC CARBON (C)

No data

1 No data

1 

No data

No data

No data 

No data 

No data

No data 

, , 1 , , , , 1 , .,!,,..! , , . 1 , . . . 1

^ a Percent

O c o o o c 

7* efl o o o c 

«> 0000

PHOSPHATE (P2 O5 )

0 No data 

0 No data 

0 No data 

0 No data

0 No data

0 No data

1 1

0 No data

1 1

0 No data

EXPLANATION

|-^ Range in content of samples *H 

Dashed where uncerta;n

1

Geometric mean of all samples reported as 

trace or more, except where noted

Ore sample groups

[ ® ]* Tertiary igneous breccia- in footwall 

of igneous dike

[ O ]* Tertiary sandstone; in hanging wall 

of low-angle fault 

[ O ] Tertiary sandstone 

[ O ] Cretaceous sandstone 

[ » ] Cretaceous shale

[ ]* Jurassic sandstone (Woodrow deposit);

in near-vertical breccia pipe

[AC ] * Jurassic limestone and sandstone 

[ 9 ] Permian sandstone 

f V ]* Permian limestone; in fcotwall of 

high-angle fault 

[ A ]* Pennsylvanian limestone; in footwall 

of high-angle fault

'Number in parentheses is samples below limit of detection,each reported as 

<0.3 and assumed to be 0.2 ppm.
DISTRIBUTION OF ELEMENTS IN THE ORES 123

TABLE 9. Ranges of concentration and the geometric means of uranium, vanadium pentoxide, sulfur, phosphate, organic 

carbon, arsenic, fluorine, selenium, and zinc in 12 sample groups of the uranium ores, northwestern New Mexico Continued

Ore sample groups 

( By formation, type of 

host rock [ ] , and 

distinctive structure* )

Espinaso Volcanics of 

Stearns (1943) [ ffi ]* 

Popotosa Formation [ O ]* 

Baca Formation [ O ] 

Dakota Sandstone [ 9 ] 

Dakota Sandstone 

(shale) [ o ] 

Morrison Formation [ ] 

Morrison Formation 

(Woodrow deposit) [ J* 

Todilto Limestone [ A ]* 

Todilto Limestone and 

Entrada Sandstone [ AC ]* 

Cutler Formation [ 9 ] 

San Andres Limestone [ V ] * 

Madera Limestone [ A ]*

Espinaso Volcanics of 

Stearns (1943) [ ® ]* 

Popotosa Formation [ O ]* 

Baca Formation [ O ] 

Dakota Sandstone [ * ] 

Dakota Sandstone 

(shale) [ » ] 

Morrison Formation [ ]

Morrison Formation 

(Woodrow deposit) [ ]* 

Todilto Limestone [ A ] * 

Todilto Limestone and 

Entrada Sandstone [ A» ]~ 

Cutler Formation [ 9 ] 

San Andres Limestone [ V ]* 

Madera Limestone [ A ]*

Espinaso Volcanics of 

Stearns (1943) [ ® ]* 

Popotosa Formation [ O ]* 

Baca Formation [ O ] 

Dakota Sandstone [ O ] 

Dakota Sandstone 

(shale) [ » ] 

Morrison Formation [ ] 

Morrison Formation 

(Woodrow deposit) [ ]* 

Todilto Limestone [ A ]* 

Todilto Limestone and 

Entrada Sandstone [ A* Y 

Cutler Formation [ 9 ] 

San Andres Limestone [ V ] * 

Madera Limestone [ A ]*

Espinaso Volcanics of 

Stearns (1943) [ ffi ]* 

Popotosa Formation [ O ]* 

Baca Formation [ o ] 

Dakota Sandstone [ O ] 

Dakota Sandstone 

(shale) [ * ] 

Morrison Formation [ ] 

Morrison Formation 

(Woodrow deposit) [ 1* 

Todilto Limestone [ A ]* 

Todilto Limestone and 

Entrada Sandstone [ * ]* 

Cutler Formation [ 8 ] 

San Andres Limestone [ V ]* 

Madera Limestone [ A ]*

^ a 

!§

2

1 

5

1

18

1 

31

1 

3 

1 

2

Parts per million

mo o o o o o O-H tn o o o o o 2

" 3, S § §

1 . i 1 ... i 1 i , , 1 , i i i 1 , .. 1 . i i i 1 , >.!.,.,! , i > 1 i , , i

ARSENIC (As)

 | 

+ 

1

' -^ 

\

+

1

FLUORINE (F)

1

1 

0 

21

0

27 

1

31

1 

1 

1 

1

1 

1 

No data

1

No data 

 | 

1

1 

1

SELENIUM (Se)

32

1 

5

1

18

1 

31

1 

43 

1 

2

1

 1 

1

 | 

1

 | 

1

 1 

1 

 | 

1

-+-

ZINC (Zn)

1

1 

18

1 

31

1 

3 

1

\

1

 1 

1 

 1 

1 

 | 

1 . 1 , , , . 1 , ,,!,,.,! , ,,!,..,! , . . 1 , . , .1 , 1 , . , .

2 One sample reported as <20, assumed to be 10 ppm.

3 Both samples reported as <0.5, assumed to be 0.3 ppm. 

<One sample reported as <0.5, assumed to be 0.3 ppm.

329-381 O 69- -9
124 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

TABLE 10. Geometric means of 16 selected elements in the ore sample groups of classes 1 and 2

[0, looked for but not found; <, less than amount shown; leaders (..), not looked for; ~, approximate amount shown. Analyses are in percent, except as otherwise

indicated]

Ore sample groups (by host rock) Ag Al Co Cr Cu Fe Mo Ni Pb U VzOs S

As F Se

Parts per million

Zn

Groups of class 1

... 0.00003

... 0

... 0

... 0

... <. 00005

... 0

... ~. 00003

3

2.6 

7 

4.8 

1.6 

3 

~9

0.0003 0.0015 

. 0005 . 001 

. 0007 . 003 

.0008 .002 

. 0004 . 001 

. 0015 . 003 

.002 .004

0. 003 1. 5 

.004 .7 

.003 .7 

.004 1.4 

.002 .3 

.003 .7 

.09 2.4

0.0007 

.0015 

.0015 

.005 

<.0011 

.0009 

<. 0014

0.0015 

.001 

.0015 

.0015 

.0007 

.0007 

.002

0.003 

<.0007 

.0015 

.006 

.005 

.003 

.025

0.14 

.16 

.18 

.26 

.14 

.10 

.10

0.27 ......

.06 0. 10 

.01 ......

.50 .3 

.14 .04 

.13 .08 

.15 .07

30 ...... 5

40 ~10 21 

10 ...... 75

40 83 48 

14 108 2. 9 

15 60 15 

55 320 2. 3

50 

16 

50 

20 

11 

12 

183

Groups of class 2

... 0.0003

.0003

... 0

... ~. 0004

4.6 

15 

3 

1.5 

3

0. 02 0. 015 

.005 .003 

. 015 . 0015 

. 0015 . 003 

. 0015 . 0046

1. 5 4. 6 

.05 2. 1 

.015 7 

.003 .7 

. 014 3. 2

0.005 

.003 

.003 

.0015 

.007

0.09 

.005 

.007 

.007 

.003

0.0015 

.015 

.03 

.007 

.05

0.14 

.13 

1.16 

.22 

.12

0.02 4.0 

.03 .11 

.03 6.6 

.43 .06 

.06 1.2

360 480 <. 5 

35 920 3. 7 

890 220 8 

41 240 10 

1.033 890 61

118 

167 

35 

830 

703

1 This sample group also contains 0.03 Ce, 0.015 I^a, ~0.01 Nd, and 0.12 Sr; 1 sample contains 0.003 Qe.

2 This sample group also contains a trace of Tl.

3 One sample in this sample group also contains 0.015 Sb and 0.015 Tl.

MORRISON FORMATION

Most data were obtained for the ore sample group 

of the Morrison Formation, the most important ore 

group in the area, from the standpoint of ore production and mine reserves. With the exception of some 

redistributed deposits in the Ambrosia Lake district 

and possibly the Gallup district, this ore group shows no 

direct, relation to tectonic structures and, with the 

exception of the ores in the Salt Wash Member, no 

stratigraphic or geographic differences.

In general, the ore group in the Morrison shows a 

somewhat greater range in content of many elements 

than most other groups of class 1. This is principally 

the result of the greater number of samples, as indicated by the similar geometric means for the respective 

elements among the several sample groups (tables 7-9). 

An exception is vanadium, which has a relatively wide 

range and an average content that is much greater 

than that of any of the other groups. (See vanadium 

pentoxide, table 9.) These differences are reflected 

mostly by sample 254040 (table 5), which was taken 

from the northwestern part of the area where ores in 

the Salt Wash Member have an average U: V ratio of 

1:7 (See table 2, Shiprock district.) Because the Salt 

Wash has a rather limited distribution, in northwestern New Mexico, the ores that have a high vanadium 

content are restricted geographically as well as stratigraphically.

MORRISON FORMATION (WOODROW DEPOSIT)

The Woodrow deposit in the Morrison Formation 

differs from the groups in class 1 in its high content 

of 10 elements, the presence of coarse-grained coffinite 

in the ore, and the close association of the deposit 

with a faulted pipelike structural feature. These differences justify assignment of the Woodrow deposit 

to class 2.

The contents of each of the following* nine elements 

in the Woodrow deposit are greater th^.n the highest 

respective contents of the sample groups in class 1 by 

the following multiples: silver, >6X ; cobalt, 7!,4X ; 

copper, 31/0 X ; iron, 3 X ; nickel, 3% X ; lead, 5 X ; 

uranium, 4% X ; sulfur, 22 X ; and arsenic, 16 X. The 

contents of lead and copper in the Wooirow are about 

the same or less than in the group in the Cutler Formation, which contains an appreciably higher content 

of these and some other elements than the groups in 

class 1. This matter is discussed below under Cutler 

Formation. The Woodrow also contains a trace of 

thallium, which is rarely detected in deposits of the 

peneconcordant type, and it also has a relatively high 

sulfide mineral content, which is expressed in the ore 

principally as pyrite and marcasite; this content is 

indicated by the high amounts of ircn and sulfur 

(table 10). Conversely, the Woodrow is low in vanadium.

The mineralogy of the Woodrow deposit is similar 

to that of the group in the Morrison Formation, 

with two exceptions: one is its relatively high sulfide mineral content, and the other is the presence of 

coarse-grained coffinite (Hilpert and Moench, 1960, 

p. 446) which occurs only in a fine-grained or earthy 

form in other deposits in the Morrison Formation 

as well as in all other peneconcordant deposits. Thus, 

the significant differences between the Woodrow 

deposit and groups of class 1 are the high grade of the 

deposit, the presence of coarse-grained coffinite in the 

ore, 'and the association of the deposit with a faulted 

pipelike structural feature.
DISTRIBUTION OF ELEMENTS IN THE ORES 125

TODILTO LIMESTONE

Unlike the other deposits of class 1, the deposits 

in the Todilto Limestone are closely associated with 

intraformational folds, the elemental assemblage differs from that of the other groups in class 1 in its 

somewhat lower amounts of iron, sulfur, and selenium (table 10), and there are other differences 

which are to be expected from a limestone rather than 

a sandstone or shale host rock (tables 5, 6). The smaller 

amounts of iron and sulfur probably reflect a lesser 

amount of sulfide minerals, and the relatively small 

amount of selenium is a corollary condition because selenium generally occurs in the sulfide minerals (Coleman 

and Delevaux, 1957).

The wider range in content of many elements in 

the group in the Todilto is similar to the range in the 

group in the Morrison and likewise is attributable to 

the greater number of samples rather than to the 

widespread distribution of samples (pi. 3).

CUTLER FORMATION

The elemental assemblage of the group in the Cutler Formation is similar to that of the class 1 groups, 

with the exception of copper, lead, zinc, and fluorine, 

which occur in substantially larger amounts and, in 

some places, are roughly comparable in quantities with 

the groups of class 2 (table 10). These relatively larger 

amounts are peculiar to deposits in the Pennsylvanian, 

Permian, and Triassic rocks of the region, particularly 

the Abo, Dockum, Chinle, and Cutler Formations. 

Many of these deposits are notable for their high 

content of copper, which may run as much as several 

percent. Little is known of their content of lead, zinc, 

and fluorine, at least in the subject area, but data on 

nearby areas indicate that at least lead and zinc occur 

in some of them in large amounts (Tschanz and others, 

1958, p, 372-377). Where copper is abundant, it generally occurs in chalcocite, bornite, and chalcopyrite 

in close association with fossil plant debris (Lindgren 

and others, 1910, p. 76-79). Such deposits are generally 

known as red-bed copper deposits, and, with minor 

variations, are worldwide in distribution.

Uranium is associated with many of the red-bed 

deposits and where substantial amounts have been 

mined as uranium ore the mineralogy of the deposits 

is known (Finch, 1954; Trites and Chew, 1955; Trites 

and others, 1959, p. 185-195). In northwestern New 

Mexico, although only the more conspicuous yellow 

and green uranium oxides have been reported, the 

mineralogy probably is similar to that of deposits of 

this type in adjoining areas. If so, the lead and zinc 

are probably also associated with galena and sphalerite, as elsewhere in the region (Garrels and Lar?e,n, 

1959, p. 71).

Conclusions are that the deposits in the group in 

the Cutler have an elemental assemblage that is similar to that of the other groups in class 1, except for 

the high content of some base metals and fluorine, 

which is peculiar to deposits in the Pennsylvanian, 

Permian, and Triassic rocks.

SAN ANDRES LIMESTONE

The group in the San Andres Limestone, which is 

represented by only one sample, is noteworthy becr.use 

of its exceptionally high content of zinc and somewhat high content of nickel (table 10). The zinc concentration ranges from 4.5 to 75 times the geometric 

mean concentrations in the groups in class 1, and the 

concentration of nickel ranges from 3.5 to 10 times the 

mean concentrations in the same group. What these 

somewhat anomalous concentrations mean is speculative 

and, by themselves, they are rather meaningless; the 

mineralogy of the deposit is incompletely known, and 

the lack of alteration of the host rock suggests a s'milarity to the deposits in the Todilto Limestone.

MADERA LIMESTONE

The group in the Madera Limestone is notable for 

its high content of iron, lead, sulfur, arsenic, fluorine, 

zinc, antimony, and thallium. These elements, especially lead, arsenic, and zinc, are more highly concentrated here than in any group of class 1. (See table 10.) 

Moreover, the group in the Madera is the only one in 

which antimony was detected and in which thallium 

was found in more than trace amounts. The moderately 

high content of iron and sulfur is probably indicative 

of the sulfide-mineral content; little is known of the 

mineralogy.

SUMMARY AND CONCLUSIONS

The elemental assemblages in the ore sample groups 

show differences that can 'be related in some instances 

to stratigraphic position, type of host rock, and tectonic 

features, but areal differences of the ores within stratigraphic units are less apparent.

In class 1, three general groupings by stratigraphic 

units can be made, principally on the basis of relative 

contents of vanadium and copper. Ores that are low in 

these two elements occur in the Baca Formation, 

Dakota Sandstone, Morrison Formation (except the 

Salt Wash Member), Todilto Limestone, and Entrada 

Sandstone. Ores that are low in vanadium but hig^ in 

copper occur in the Cutler Formation, These ores also 

probably are relatively high in lead, zinc, and fluorme. 

Ores that are high in vanadium and low in copper 

occur in the Salt Wash Member of the Morr;son
126 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

Formation. The differences among rock types in class 1 

ores are not marked, and the class is notable for the general uniformity of ores in sandstone, shale, and limestone. The most 'apparent difference is the relatively 

low contents in the Todilto Limestone of iron, sulfur, 

and selenium, which collectively are indicative of a 

low sulfide content. The ores in this class, except for 

the ones in the Todilto Limestone, show no close relation to tectonic features; these ores are almost invariably related to intraformational folds.

The ores of class 2 have rather marked differences 

among groups, but sample data are generally too few 

to determine the relations as to stratigraphic position, 

type of host rock, structural features, or area. As a 

class, the assemblage of elements is relatively high in 

base and ferrous metals, in sulfur, arsenic, and fluorine, and probably in thallium, and it is relatively low 

in vanadium. The one characteristic that is common to 

all groups in this class is the close association of the 

deposits with faults. Moreover, the faults all occur 

within or along the margins of the Bio Grancle trough 

(pi. 1). Most of these faults formed contemporaneously 

with the Rio Grande trough, except for the Woodrow 

pipe. Although it occurs near the margin of the 

trough, it probably formed earlier than the trough 

and probably is intraformational, whereas the other 

fault structures are interformational.

The characteristics listed above for the two classes 

of ore sample groups and related deposits, when 

applied to the other uranium deposits in northwestern 

New Mexico, indicate that most, deposits belong in 

class 1, some belong in class 2, and relatively few 

specifically the ones in pegmatite do not belong in 

either class. Although this application is based on incomplete information, particularly regarding the elemental assemblages, it is helpful in the subsequent 

appraisal of the resources.

Of the deposits that belong in class 1, the largest 

number is low in both vanadium and copper and constitutes most, if not all, of the deposits in the Santa 

Fe Group, Galisteo, San Jose, Baca, and Nacimiento 

Formations, Ojo Alamo Sandstone, Fruitland Formation, Mesaverde Group, Mancos(?) Shale, Dakota 

Sandstone, Morrison Formation (except for the Salt 

Wash Member), Summerville Formation, Todilto 

Limestone, and Entracla Sandstone. Next in abundance are the deposits that are high in copper and low 

in vandium; they constitute all those in the Chinle, 

Dockum, Cutler, and Abo Formations and include a 

deposit in the Maclera Limestone in Rio Arriba 

County. Deposits that are high in vanadium and low 

in copper occur only in the Salt Wash Member of the 

Morrison Formation.

Class 2 deposits comprise those in tl °i intrusive 

rocks of varied composition and form, th?. older volcanic rocks of the Jemez Mountains, Popotosa and 

Datil Formations, and other rocks in the San Andres 

and Maclera Limestones.

DISTRIBUTION OF ELEMENTS IN THE TODILTO 

LIMESTONE

PURPOSE AND METHODS OF ANALYSIS

In addition to the ore samples taken from the 

Todilto Limestone (table 6) and discussed in the preceding section, samples of the mineralized and barren 

Todilto were taken in the vicinity of and away from 

ore deposits. The purpose of the sampling was to 

determine the spatial relations of the deposits to the 

various elements in the Todilto and to determine the 

relations of the deposits to the Todilto gypsum unit, 

as a means of helping to appraise tl °s uranium 

resources.

Of 54 selected samples, 51 were taken from the 

limestone unit and three from the gypsum unit at the 

sample localities shown on plate 3, which also shows 

the known uranium deposits in the Todilto and isopach lines drawn on the limestone and gypsum units.

The samples were taken at outcrop and from drill 

holes. Of the 51 from the limestone unit, 22 were from 

drill-hole cuttings, 21 were chip-channel samples from 

the outcrop, and eight were grab samples from quarries and outcrop. Each sample weighed about 5 

pounds. Most samples represent the entire thickness 

of the limestone unit. Exceptions were samples 252610 

and 252609, which represent the basal 5-foot and 

overlying 4-foot strtitigraphic intervals, respectively, 

at the same locality; sample 252616, which represents 

the basal 4-foot interval; and sample 252615, which 

represents a 1-foot interval 4 feet above the base at 

different nearby localities. The three samples of the 

gypsum unit (pi. 3) were taken near or at the base; 

samples 252608 and 252612 were composite chunk samples taken within the basal 10-foot interval, and sample 252617 represents the basal 4-foot interval. This 

latter interval is rather calcareous at the sample 

locality.

Semiquantitative spectrograpliic and chemical analyses were made of the Todilto samples for the same 

elements that were determined for the Todilto ores. 

The analytical data for the ores and for four zones 

away from ore are listed in tables 6 and 11, and, for 

comparative purposes, the ranges in concentration and 

the geometric means are plotted in graphs in tables 

12-14 in the same manner as was done for the ores in 

the formational groups. Analytical data for the gypsum unit are listed in table 15.
DISTRIBUTION OF ELEMENTS IN THE ORES 127

TABLE 11. Semiquantitative spectrographic, radiometric, and chemical analyses of samples of barren and uraniferous Todilto Limestone,

northwestern New Mexico and northeastern Arizona

Spectrographic determinations are semiquantitative and were made by the rapid visual-comparison method. Comparisons of similar data with those obtained by quantitative 

methods show that the assigned semiquantitative class interval includes the quantitative value in about 60 percent of the determinations. Figures are reported to the 

nearest number in the series >10, 7, 3, 1.5, 0.7, 0.3, 0.15, and are coded as follows: >10=1, 7=2, 3=3, 1.5=4, 0.7=5, 0.3=6, 0.15=7, 0.07=8, 0.03=9, 0.015=10, 0.007=11, 

0.003=12, 0.0015=13, 0.0007=14, 0.0003=15, 0.00015=16. Figures reported as less than «) are coded as follows: <1.0=a, <0.05=b, <0.02=c. 0, looked for but not fouTd; 

<, less than amount shown, standard detectability does not apply; Tr., trace; leaders (_.), not looked for; number enclosed in parentheses near threshold of detectability; 

ND, no data.

[Spectrographic analyses are in percent, coded; other analyses are in percent or parts per million, as indicated, and are not coded]

Sample

Type of Location

otherwise indicated. See pi. 3.) Ag

Spectrographic 

Al As Au B Ba Be Bi Ca Cd Ce Co Cr Cs Cu Dy Ilr

Mineralized ground

238805 

238810. __

238840...

238847. .. 

238849....

Drill-hole SEMsec.SO.T. 13 N., R. 9W.,McKin- 0 

cuttings. ley County.

._.._do._ ____ NWMNW^NEM sec. 30, T. 13 N., R. 0

9W., McKinley County. 

Chip channel. SEMNEM sec. 4, T. 12 N., R. 9 W., 0 

Valencia County. 

...-do- --.- SWMSWMSEM sec. 4, T. 12 N., R. 9 0

W., Valencia County.

300

400 

300

400 

400

0

0 

0

0 

0

10 0

10 0 

10 0

10 0 

10 0

0

0 

0

0 

0

1

1 

1

1 

1

0

0 

0

0 

0

0

0 

0

0 

0

0

14 

0

0 

0

11 ND

13 ND 

13 ND

15 ND 

13 ND

13

13 

13

13 

13

0

0 0 

0 0

0 0 

0 0

>25 feet and <500 feet from known uranium deposit

238819... 

238848 

238806 

238809. __

238828. ...

238829 

238830...

238831 

238832...

238833...

238834...

238835...

238823 

Drill-hole SEJ£SEJ£ sec. 23, T. 13 N., R. 10 W., 0 

cuttings. McKinley County, 

-....do -._-. SWMSWJ4SWM sec. 3, T. 12 N., R. 9 0

W., Valencia County. 

.....do.... ...-. SEMsec.30,T. 13N., R.9W.,McKin- 0

ley County.

___.-do -.-.----.-do __ _ _-- __ -_ 0

__-_-do -___-_.__. do... -._-__.___._____---_-___.___._ 0

..... do....... ...... .do.... .....----.-.-.-------------- 0

.....do -.-.----.-do -..-..__.-.--..---...-.-----.- 0

 ..do --.-.-----do --------------------------- 0

Chip channel. SWJ£ sec. 8, T. 8 N., R. 5 W., Valencia 0 

County.

400 

300 

300

300 

300 

300 

300 

300 

300 

300 

300 

300 

500

Tr. 

Tr. 

0

0 

0 

Tr. 

Tr. 

Tr. 

Tr. 

Tr. 

Tr. 

Tr. 

0

9 0 

8 0 

10 0

8 0 

10 0 

10 0 

10 0 

10 0 

10 0 

10 0 

8 0 

7 0 

11 0

0 

0 

0

0 

0 

0 

0 

0 

0 

0 

0 

0 

0

1 

1 

1

1 

1 

1 

1 

1 

1 

1 

1 

1 

1

0 

0 

0

0 

0 

0 

0 

0 

0 

0 

0 

0 

0

0 

0 

0

0 

0 

0 

0 

0 

0 

0 

0 

0 

0

0 

0 

0

0 

14 

0 

14 

0 

0 

0 

0 

0 

0

13 ND 

13 ND 

13 ND

13 ND 

12 ND 

13 ND 

12 ND 

12 ND 

12 ND 

13 ND 

12 ND 

12 ND 

13 ND

13 

12 

13

13 

13 

13 

13 

13 

13 

13 

13 

11 

14

0 0 

0 0 

0 0

0 0 

0 0 

0 0 

0 0 

0 0 

0 0 

0 0 

0 0 

0 0 

0 0

>500 feet and <1 mile from known uranium deposit

239622... 

246069....

238841....

238850.. _.

238814... 

238815....

238816.__.

238817..-.

238818.-..

238836....

238837..-.

Chip channel- By road, west side Horse Mesa, 0 

Apache County, Ariz.

Ben 3, San Juan County (unsurveyed) . 

.-.-do- -.-. NWMNEM sec. 33, T. 9 N., R. 5 W., 0

Valencia County. 

.....do------ Center Sy2 sec. 22, T. 9 N., R. 5 W., 0

Valencia County. 

Drill-hole Sec. 23, T. 13 N., R. 10 W., McKinley 0 

cuttings. County.

.. do --- .--do ---------.---- ------- 0

. .do do -_ __-..-- -------- 0

.....do. -... SEJi sec. 30, T. 13N., R.9W.,McKin- 0

ley County. 

...-do- ____-__ do. _ _ -_ - _ _ 0

600 

400

400 

300 

300

300 

400 

400 

400 

300

300

0 

0

0 

0 

0

0 

0 

0 

0 

0

0

11 0

10 0

9 0 

8 0 

8 0

7 0 

8 0 

8 0 

8 0 

10 0

8 0

0 

0

0 

0 

0

0 

0 

0 

0 

0

0

1 

1

1 

1 

1

1 

1 

1 

1 

1

1

0 

0

0 

0 

0

0 

0 

0 

0 

0

0

b

0 

0 

0

0 

0 

0 

0 

0

0

0 

0

0 

0 

14

0 

0 

0 

0 

0

0

14 -----

13 -..-.-

13 ND 

13 ND

12 ND

12 ND 

13 ND 

13 ND 

13 ND 

12 ND

12 ND

12 

10

13 

12 

12

12 

13 

13 

13 

12

12

0 0 

0 0

0 0 

0 0 

0 0

0 0 

0 0 

0 0 

0 0 

0 0

0 0

See footnote at end of table.
128 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

TABLE 11. Semiquantitative spectrographic, radiometric, and chemical analyses of samples of barren and uraniferous TodiUo Limestone,

northwestern New Mexico and northeastern Arizona Continued

Sampl<

Type of 

s sample

Location

otherwise indicated. See pi. 3.) Ag Al As Au B Ba

Spectrographic '

Be Bi Ca Cd Ce Co Cr Cs Cu Dy Er

> 1 mile from known uranium deposit

239623... Chip channel. 

238838- -do

238820..

238821. .

238822..

238843..

238812-

238813-

238824- 

238825..

238839..

252607- 

252609. . 

252610. .

252616. .

252613- .

252614. .

252615. .

239624.. 

252611..

246068..

246070. .

. Grab... ...

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

 do..... ....

..--do ....

 ..do -..--

.--.-do .....

. Chip channel . 

. -do ._.

. Grab. _._. 

. Chip channel - 

 -do 

 do ...

..-..do --..-

--..do- --.

 do 

. Grab-.. ......

. Chip channel . 

-.. do ....

..-..do .

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

South side Todilto Wash, Todilto 0 5 0 0 0 12 

Park, McKinley County (unsurveyed). 

NWJi sec. 12, T. 15 N., R. 17 W., 0 6 0 0 0 11 

McKinley County. 

In pit, center WJ^W^ sec. 17, T. 14 N., 0 4 0 0 0 10 

R. 12 W., McKinley County, 

-...-do -_.-_ .__ 0 4 0 0 0 10

.-.-.do ... . .... 030009

In pit, SE}4SE}4NW}4, sec. 28, T. 10 0 5 0 0 0 10 

N., R. 9 W., Valencia County.

NW^SEJi sec. 4, T. 8 N., R. 5 W., 0 6 0 0 0 9 

Valencia County. 

SW^sec.34,T. 9 N.,R. 5 W., Valencia 050009 

County. 

Center S^S^S^ sec. 14, T. 9 N., R. 0 4 0 0 0 11 

5 W., Valencia County. 

NE}^NW}4 sec. 7, T. 9 N., R. 4 W., 0 5 0 0 0 10 

Valencia County. 

NEJisec. 12, T. 9N., R. 5W., Valen- 040008 

cia County.

SWJi sec. 13, T. 15 N., R. 1 E., San- 0 5 0 0 0 12 

doval County. 

SW}^ sec. 13, T. 16 N., R. 1 W., (pro- 0 3 0 0 Tr. 10 

jected), Sandoval County.

-do - -. . -. 0 5 0 0 0 11

NWJ4 sec. 17, T. 23 N., R. 1 E., Rio 0 5 0 0 0 11 

Arriba County. 

NE^NWJi sec. 8, T. 24 N., R. 4 E., 0 5 0 0 0 11 

Rio Arriba County. 

NEJ£ sec. 25, T. 11 N., R. 5 E., Ber- 040009 

nalillo County. 

SEJi sec. 28, T. 25 N., R. 4 E., Rio 0 5 0 0 0 12 

Arriba County.

0 0

0 0 

0 0

0 0 

0 0 

0 0 

0 0

0 0 

0 0

0 0 

0 0 

0 0 

0 0

0 0 

0 0

0 0

0 0 

0 0 

0 0

0 0 

0 0 

0 0

1

1 

1

1

1 

1 

1

1 

1

1 

1 

1 

1

1 

1

1

1 

1 

1

1 

1 

1

0

0 

0

0 

0 

0 

0

0 

0

0 

0 

0 

0

0 

0

0

0 

0 

0

0 

0 

0

b

0 

0

0 

0 

0 

0

0 

0

0 

0 

b 

b

b

b

b

b 

b 

b

b

0

0 

0

14 

14 

0 

0

0 

0

0 

0 

0 

0

0 

0

0

0 

0 

0

0 

0 

0

13 ......

12 ND 

13 ND

13 ND 

13 ND 

13 ND 

12 ND

14 ND

14 ND

13 ND 

13 ND 

13 ......

13 ......

13 ......

13

12 ......

14 ......

14 ......

14 ---.

14 ......

13 ......

13 ......

13

14 

13

13 

13 

13 

14

14 

13

14 

13 

14 

14

14 

13

12

13 

13 

13

13 

12 

12

0

0 

0

0 

0 

0 

0

0 

0

0 

0 

0 

0

0 

0

0

0 

0 

0

0 

0 

0

0

0 

0

0 

0 

0 

0

0 

0

0 

0 

0 

0

0 

0

0

0 

0 

0

0 

0 

0

Spectrographic 1

Eu F Fe Ga Gd Ge Hf Hg Ho In Ir K La Li La Mg Mn Mo

Mineralized ground

2 

38805. ..

238810-

238840-

238847... 

238849 

. Drill-hole 

cuttings.

 ___do -----

. Chip channel . 

-- do.. .-.

SEMsec.30,T. 13 N., R. 9W.,McKin- ND ND 6 Tr. 0 0 0 

ley County. 

 do - - ND ND 6 Tr. 0 0 0

NWMNWJ4NEi4sec.30, T. 13 N., R. 9 ND ND 6 Tr. 0 0 0 

W., McKinley County. 

SEV4NE>4 sec. 4, T. 12 N., R. 9 W., ND ND 6 0 0 0 0 

Valencia County. 

SW}4SWKSEJi sec. 4, T. 12 N., R. 9 ND ND 6 Tr. 0 0 0 

W., Valencia County.

0 ND

0 ND 

0 ND

0 ND

0 ND

0

0 

0

0 

0

0

0 

0

0 

0

3

5 

3

0

5

0

0 

0

0 

0

0 ND

0 ND

0 ND

0 ND 

0 ND

6

5 

5

5 

6

8

7 

8

7 

8

0

0 

0

0 

0

>25 feet and <500 feet from known uranium deposit

238819. .. 

238848-

238806. ..

238809-

2388:8.-.

238829...

238830. .

238831-

238832. _.

238833-

238834..

238835 _

238823-

. Drill-hole 

cuttings.

. ..do --.

.. do --..

.- do ---_.

.- do .

.._._. do .__..

....-do __-.

. do ...--.

 do --.

..__-do .....

- .do - -..

Chip channel. .

SEJ^SE^sec. 23, T. 13 N., R. 10W., ND ND 6 Tr. 0 0 0 

McKinley County. 

SWkSW^SWJ^ sec. 3, T. 12 N., R. 9 ND ND 5 Tr. 0 0 0 

Valencia County. 

SE^sec.30,T. 13 N., R. 9W.,McKin- ND ND 6 Tr. 0 0 0 

ley County, 

 do ND ND 6 Tr. 0 0 0

 do - _ _. ND ND 6 Tr. 0 0 0

. do - - --- ND ND C Tr. 0 0 0

 do - - ND ND 5 Tr. 0 0 0

 do ND ND 6 Tr. 0 0 0

..--.do. -____ . _-____. ND ND 5 Tr. 0 0 0

. do-- ND ND 5 Tr. 0 0 0

 do___- _ ND ND 5 Tr. 0 0 0

.. do . ND ND 5 Tr. 0 0 0

SWM sec. 8, T. 8 N., R. 5 W., Valencia. ND ND 7 0 0 0 0 

County.

0 ND 

0 ND 

0 ND

0 ND 

0 ND 

0 ND 

0 ND 

0 ND 

0 ND 

0 ND 

0 ND 

0 ND 

0 ND

0 

0 

0

0 

0 

0 

0 

0 

0 

0 

0 

0 

0

0 

0 

0

0 

0 

0 

0 

0 

0 

0 

0 

0 

0

3 

3 

3

3 

3 

3 

3 

3 

3 

3 

3 

3 

0

0 

0 

0

0 

0 

0 

0 

0 

0 

0 

0 

0 

0

0 ND 

0 ND 

0 ND

0 ND 

0 ND 

0 ND 

0 ND 

0 ND 

0 ND 

0 ND 

0 ND 

0 ND 

0 ND

5 

5 

5

5 

5 

5 

5 

5 

5 

6 

5 

6 

5

8 

8 

7

8 

8 

8 

8 

8 

8 

8 

7 

7 

9

0 

0 

0

0 

0 

0 

0 

0 

0 

0 

0 

0 

0

See footnote at end of table.
DISTRIBUTION OF ELEMENTS IN THE ORES

TABLE 11. Semiquantitative spectrographic, radiometric, and chemical analyses of samples of barren and uraniferous TodiUo Limestone,

northwestern New Mexico and northeastern Arizona Continued

Type of Location

otherwise indicated. See pi. 3.) Eu

Spectrographic »

F Fe Ga Gd Ge Hf Hg Ho In Ir K La Li Lu Mg Mn Me

>500 feet and <1 mile from known uranium deposit

239622.. Chip channel.. By road, west side Horse Mesa, _____

Apache County, Arizona. 

246069.-----.. do... ...... Roadcuti 1,000 feet NWH Joe Ben .....

3, San Juan County (unsurveyed). 

238841.-----.. do. . _... NWJ<NEJ< sec. 33, T. 9 N., R. 5 W., ND

Valencia County. 

238850...----. do ----- Center S}^ sec. 22, T. 9 N., R. 5 W., ND

Valencia County. 

238814.-- Drill-hole Sec. 23, T. 13 N., R. 10 W., McKinley ND 

cuttings. County. 

238815-. -do . do -- .-.-- . ------ ND

238816. -.-do- .- -.-do. ----- - - ----.----- ND

238817-...- ..do ., .-- .do- . . - ND

238818..----.do.. . .__-.. -.do. -------------------- ND

238836.- ----do -.- SEJ< sec. 30, T. 13N., R.9W., McKin- ND

ley County. 

238837------.dO - __ -do --------------------- ND

 ... 8

--...-- 6

ND 6 

ND 6 

ND 5

ND 6 

ND 6 

ND 6 

ND 6 

ND 6

ND 6

0 0 

0 0 

0 0 

Tr. 0 

Tr. 0

Tr. 0 

Tr. 0 

Tr. 0 

Tr. 0 

Tr. 0

Tr. 0

0 0 

0 0 

0 0 

0 0 

0 0

0 0 

0 0 

0 0 

0 0 

0 0

0 0

0 ....-_

0 ND 

0 ND 

0 ND

0 ND 

0 ND 

0 ND 

0 ND 

0 ND

0 ND

0 

0 

0 

0 

0

0 

0 

0 

0 

0

0

0 

0 

0 

0 

0

0 

0 

0 

0 

0

0

0 

4 

5 

4 

3

4 

4 

4 

4 

4

4

0 

0 

0 

0 

0

0

0 

0 

0 

0

0

0 _.-...

0 ND 

0 ND 

0 ND

0 ND 

0 ND 

0 ND 

0 ND 

0 ND

0 ND

6 

5 

4 

4 

5

5 

6 

5 

5 

5

5

8 0 

8 0 

8 0 

7 0 

8 0

8 0 

8 0 

8 0 

8 0 

8 0

8 0

>1 mile from known uranium deposit

239623-- Chip channel.. South side Todilto Wash, Todilto Park ...

McKinley County (unsurveyed). 

238838. ..--.-do -- NWJ£ sec. 12, T. 15 N., R. 17 W., ND

McKinley County. 

238820 Grab-- In pit .center W^W^sec. 17, T.14N., ND

R. 12 W., McKinley County. 

238821-.--_-_.dO ._--___--dO ------------.------------ - ND

238822..-..-dO - .---.-.-do -------------------------- ND

238843----_-dO ._.-__--dO ------------------------ ND

238812_____ -.do --_. In pit, SEJ<SEJ<NWJ<, sec. 28, T. 10 ND

N., R. 9 W., Valencia County. 

238813-.---dO- .------do ---------------------- ND

238824-- Chip channel.. NWJ<SEJ< sec. 4, T. 8 N., R. 5 W., ND 

Valencia County. 

238825_-_-. ..do .-- SW>4 sec. 34,T. 9 N., R.5W., Valencia ND

County. 

238839.- Grab-----..-. Center S^S^S^ sec. 14, T. 9 N., ND

R. 5 W., Valencia County. 

252607- Chip channel.. NEJ<NWJ< sec. 7, T. 9 N., R. 4 W., 0 

Valencia County. 

252609---.. -.do......... NEJ<sec. 12, T. 9N., R., 5W.,Valen- 0

cia County. 

252610 .--do. . do -. - ----- - 0

252616---- --do- _ -__. SWJ£ sec. 13, T. 15 N., R. 1 E., 0

Sandoval County. 

252613-_.----dO -...- SWJ< sec. 13 T. 16 N., E. 1 W., (pro- 0

jected), Sandoval County. 

252614_..----dO -__--_-do -------------------------- 0

252615 Grab.. do . - 0

239624-. Chip channel.. NWJ< sec. 17, T. 23 N., R. 1 E., Rio ------

Arriba County. 

252611----. -do... ----- NEJ<NWJ< sec. 8, T. 24 N., R. 4 E., 0

Rio Arriba County. 

246068---.---.dO --__ NEJ£ sec. 25, T. 11 N., R. 5 E., .____.

Bernalillo County. 

246070.---.. -do -___ SEJ£ sec. 28, T. 25 N., R. 4 E., Rio 

Arriba County.

....... 7

ND 7 

ND 7

ND 6 

ND 6 

ND 6 

ND 7

ND 7 

ND 7

ND 7 

ND 6

..-__- 7 

-_--_- 6

--..- 7

------ 6

-___-_ 6

,.. 7

-__--- 7

-..___ 7

.__... 7

------ 6

0 0 

0 0 

Tr. 0

Tr. 0

Tr. 0 

Tr. 0 

0 0

0 0 

0 0

0 0 

0 0 

0 0 

0 0

0 0 

0 0

Tr. 0

0 0 

0 0 

0 0

0 0 

0 0 

0 0

0 0 

0 0 

0 0

0 0 

0 0 

0 0 

0 0

0 0 

0 0

0 0 

0 0 

0 0 

0 0

0 0 

0 0

0 0

0 0 

0 0 

0 0

0 0 

0 0 

0 0

0 .-

0 ND 

0 ND

0 ND 

0 ND 

0 ND 

0 ND

0 ND 

0 ND

0 ND 

0 ND 

0 0 

0 0

0 0 

0 0

0 0

0 0 

0 0 

0 -.___.

0 0 

0 ...-__

0 .--_--

0 

0 

0

0 

0 

0 

0

0 

0

0 

0 

0 

0

0 

0

0

0 

0 

0

0 

0 

0

0 

0 

0

0 

0 

0 

0

0 

0

0 

0 

0 

0

0 

0

0

0 

0 

0

0 

0

0

0 

0 

4

4 

3 

4 

0

0 

0

0 

5 

0 

0

4 

5

3

0 

0 

0

0 

a 

4

0 

0 

0

0 

0 

0 

0

0 

0 

0

0 

0

0

0 

0

0

0 

0 

0

0 

0 

0

0 ......

0 ND 

0 ND

0 ND 

0 ND 

0 ND 

0 ND

0 ND 

0 ND

0 ND 

0 ND 

0 0 

0 0

0 0 

0 0

0 0

0 0 

0 0 

0 ..-.-.

0 0

0 ------

5 

6 

5

4 

4 

4 

5

5 

5

4 

5 

6 

5 

6

5

5 

6 

5

5 

4 

5

8 0 

7 0 

8 0

8 0

7 0 

8 0 

8 0

7 0 

9 0

8 0 

7 0 

7 0 

8 0

8 0 

9 0

9 0

9 0 

8 0 

9 0

9 0 

9 0 

9 0

Spectrographic '

Na

238805... Drill-hole SEJ< sec. 30, T. 13 N., R. 9 W., 4

cuttings. McKinley County. 

238810.. do . .do .-- . 5

238840__-----. do. ._.._ NWJ<NWJ<NEJ< sec. 30, T. 13 N., 5

R. 9 W., McKinley County. 

238847-.. Chip channel- SEJiNEJi sec. 4, T. 12 N., R. 9 W., 6 

Valencia County. 

238849---- ..do ----- SWJiSWJ4SE^ sec. 4, T. 12 N., R. 6

9 W., Valencia County.

Nb Nd

Mineri

0 0

0 0 

0 0

0 0 

0 0

Ni Os

ilized ground

14 0

14 0 

14 0

0 0 

14 0

P Pb

0 0

0 0 

0 13

0 Tr. 

0 12

Pd Pr

0 ND

0 ND 

0 ND

0 ND 

0 ND

Pt

0

0 

0

0 

0

Rb

ND

ND 

ND

ND 

ND

Re

0

0 

0

0 

0

Rh

0

0

0

0 

0

Ru Sb

0 0

0 0 

0 0

0 0 

0 0

Sc

0

0 

0

0 

0

Si SD

1 0

3 0

2 0

3 0 

3 0

See footnote at end of table.
130 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

TABLE 11. Semiquantitative spectrographic, radiometric, and chemical analyses of samples of barren and uraniferous TodiUo Limestone,

northwestern New Mexico and northeastern Arizona Continued

Type of Location

otherwise indicated. See pi. 3.)

Soectrographic

Na Nb Nd Ni Os P Pb Pd Pr

1 Continued

Pt Bb Be Bh Bu Sb Sc Si Sn

>25 feet and <500 feet from known uranium deposit

238819...

238848 

238806 

238809-..

238828-...

238829 

238830- ...

238831...

238832 

238833...

238834 

238835 

238823...

Drill-hole SEJ^SE^ sec. 23, T. 13 N., B. 10 W.,

cuttings. McKinley County.

-----do_....-_- SWMSWMSWM sec. 3, T. 12 N., B.

9 W., Valencia County.

_._. -do.. ..-.-.- SEM sec. 30, T. 13 N., B. 9 W.,

McKinley County.

-_-._do..--....-.-.--do _ ___....-.-._... ... , .._-.-_

.....do __ ._.--._. _do. _ -_.__-...-.._-..._.-..--.-.-.

.._._do _ ...---...do _ -.--..--. . .

..._-do __ ...-..-.-do _ ----.--.-...- ... . _ ......

.-. _do __ ._.--_- .do _ . -___._..-_-._._._.. .._._._

.....do. .......--. _._do.. _ .._.._._....-.....-.-.._._._

.____do _ -_. _.-.-_do _ ----.-.-.. . . ... .

.___.do _ -.-..-----do _ _____..._ . . . . .

.-._.do _ __.__. ____do_... _____-.-_..--.__- .._ -.__._-

Chip channel- SWM sec. 8, T. 8 N., B. 5 W., Valencia

County.

4 0 0 14 0

5 0 0 14 0

4 0 0 14 0

50000

4 0 0 14 0

4 0 0 14 0

4 0 0 14 0

4 0 0 14 0

4 0 0 14 0

4 0 0 14 0

4 0 0 13 0

4 0 0 14 0

6 0 0 Tr. 0

0 0

0 0

0 0

0 0

0 0

0 Tr.

0 Tr.

0 Tr.

0 Tr.

0 Tr.

0 Tr.

0 13

0 0

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1

1

1

2

1

1

1

1

1

1

1

1

4

n

0

0

0

0

0

0

0

0

0

0

0

0

>500 feet and <1 mile from known uranium deposit

239622...

246069.-..

238841. __.

238850-...

238814. __

238815....

238816..-.

238817.--.

238818..-.

238836.-..

238837

Chip channel - By road, westside Horse Mesa,

Apache County, Ariz.

.-...do. ........ Boadcut ±1,000 feet northwest of

Joe Ben 3, San Juan County

(unsurveyed).

.-.--do ._._-_ NWMNEM see. 33, T. 9 N., B. 5 W.,

Valencia County.

....-do....----- Center SK sec. 22, T. 9 N., B. 5 W.,

Valencia County.

Drill-hole Sec. 23, T. 13 N., B. 10 W., McKinley

cuttings. County.

.-.-.do _ ..._---...do _ ..-.._-___.-.-._.--.-_-.__ ..

.._-_do- _ __.__. ....do _ __-.__..._..-_._.____.....-..

.____do _ .._._- _.-.do _ ..-____._-..-._._.. __....

.-...do _ ------- ...do _ _ -----___-__--_-.___._.-_-_-

 -do..... . SEM sec. 30, T. 13 N., E. 9 W.,

McKinley County.

._ __do _ -.-.-..-.-do __ .... -.._.___ .. . .....__ _

70000

6 0 0 14 0

4 0 0 14 0

3 0 0 13 0

5 0 0 14 0

5 0 0 14 0

5 0 0 14 0

5 0 0 14 0

5 0 0 14 0

5 0 0 14 0

4 0 0 14 0

0 0

0 Tr.

0 13

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 ..--._

0 ......

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 -..-..

0 -----

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

4

2

3

3

1

2

2

2

2

1

2

0

0

0

0

0

0

0

0

0

0

>1 mile from known uranium deposit

239623-..

238838--..

238820

238821....

238822_-_.

238843---.

238812-.-.

238813- 

238824. _ _

238825. _. -

238839 

252607 

252609-.. .

252610....

252616.--.

252613-.-.

252614 

252615...

239624 

252611 -

246068.-..

246070--..

Chip channel. South side Todilto Wash, Tedilto

Park, McKinley County (unsurveyed).

.--.-do ------ NWM sec. 12, T. 15 N., B. 17 W.,

McKinley County.

Grab.... ....._ Tn pit, center WJiW>£ sec. 17, T. 14 

N., B. 12 W., McKinley County.

. do . . do___. __ _ __ _ __

____do _ ------ _--_do _ _-- _ -_______ __--__

.....do _ ------ do__ _ _.____. ._-...-.__._-_._._..

.-..-do .--._- In pit, SEMSEMNWM, sec. 28, T. 10

N., R. 9 W., Valencia County.

_ do _ ...__- __do _ .---.----........_......-.....

Chip channel. NWMSEM sec. 4, T. 8 N., B. 5 W.,

Valencia County.

- do___. -.._- SWJ4sec.34, T.9N., B. 5 W., Valencia

County.

Grab.. .._._._. Center S^S^SK sec. 14, T. 9 N.,

B. 5 W., Valencia County.

Chip channel. NE^NWM sec. 7, T. 9 N., B. 4 W.,

Valencia County.

.-.-do- -.-- NEMsec. 12, T. 9 N., B.5W., Valencia County.

.---.do. . __.,__.. _do _ .__-._-_.-_.-.-__...._..-.-_.

_--_do.. --._._. SWJ4 sec. 13, T. 15 N., B. 1 E., San--

doval County.

.--.-do....----- SWM sec. 13, T. 16 N., B. 1 W., (projected), Sandoval County.

.. do _ __ .___ _do _ .-----_-...--.__._..__._.-.-__

Grab.. ........... __do... ...___ ______. _ _

Chip channel- NWM sec. 17, T. 23 N., B. 1 E., Bio

Arriba County.

...--do....--... NEMNWM sec. 8, T. 24 N., B. 4 E.,

Bio Arriba County.

.---.do......... NEM sec. 25, T. 11 N., B. 5 E.,

Bernalillo County.

.-.._do ---_- SEM sec. 28. T. 25 N., B. 4 E., Bio

Arriba County.

60000

60000

4 0 0 14 0

4 0 0 14 0

4 0 0 14 0

5 0 0 14 0

70000

50000

6 0 0 Tr. 0

6 0 0 Tr. 0

4 0 0 14 0

7 0 c 0 0

6 0 c 14 0

6 0 c 15 0

6 0 c 14 0

5 0 c 13 0

7 0 c 14 0

7 0 c 0 0

70000

7 0 c 15 0

6 0 0 14 0

6 0 0 14 0

0 0

0 0

0 0

0 0

0 Tr.

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 14

0 Tr.

0 ......

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ._-_..

0 ---._.

0 .---._

0 ------

0 .-.-._

0 ------

0 -..-_-

0 ------

0 ------

0 _..._-

0 ------

0 _---.-

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ND

0 ------

0 ._-_..

0 .---_-

0 -.--.-

0 ------

0 _---.-

0 ..._.-

0 ------

0 ------

0 _..---

0 ------

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

3

3

2

2

1

2

4

3

4

4

3

3

2

3

3

2

3

3

4

3

3

4

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

See footnote at end of table.
DISTRIBUTION OF ELEMENTS IN THE ORES 121

TABLE 11. Semiquantitative spectrographic, radiometric, and chemical analyses of samples of barren and uraniferous Todilto Limestone,

northwestern New Mexico and northeastern Arizona Continued

Sample

Type of Location

otherwise indicated. See pi. 3.)

SpectrograpMc 1 Continued

Sr Sm Ta Tb Te Th Ti Tl Tm U V W Y Yb Zn Zr

Mineralized ground

238805... 

238810...

238840....

238847... 

238849....

Drill-hole SE}< sec. 30, T. 13 N., K. 9 W.,-Mccuttings. Kinley County.

.....do .---- NW}<NW}<NE}< sec. 30, T. 13 N.,

R. 9 W., McKinley County. 

Chip channel. SEJ£NEJ£ sec. 4, T. 12 N., R. 9 W., 

Valencia County. 

.....do........ SWj-fSWKSEJi sec. 4, T. 12 N., R.

9 W., Valencia County.

10 0

9 0 

8 0

8 0 

9 0

0 ND

0 ND

0 ND

0 ND 

0 ND

0 0

0 0 

0 0

0 0 

0 0

8

9

8

9 

9

0 ND

0 ND 

0 ND

0 ND 

0 ND

0

0 

0

0

7

7

8 

9

9

8

0 0 .

0 0 .

0 Tr. 

0 0 

0 0 .

0 

0

0 11

0 11 

0 10

0 12 

. 0 12

>25 feet and <500 feet from known uranium deposit

238819... 

238848--..

238806....

238809....

2388:8....

238828....

238830....

238831....

238832....

238833....

238834....

238835....

238823...

Drill-hole SE}£SE}< sec. 23, T. 13 N., R. 10 W., 

cuttings. McKinley County. 

.... do. ..--. SWJ-iSWJiSWJi sec. 3, T. 12 N., R.

9 W., Valencia County. 

.....do. --.-- SEJi sec. 30, T. 13 N., R. 9 W., McKinley County.

.....do. _ ....-----.do _ ----------..-...--.-.-----.-.

Chip channel. SW}< sec. 8, T. 8 N., R. 5 W., Valencia 

County.

9 0 

9 0 

10 0

9 0 

9 0 

9 0 

9 0 

9 0 

9 0 

9 0 

9 0 

9 0 

8 0

0 ND 

0 ND 

0 ND

0 ND 

0 ND 

0 ND 

0 ND 

0 ND 

0 ND 

0 ND 

0 ND 

0 ND 

0 ND

0 0 

0 0 

0 0

0 0 

0 0 

0 0 

0 0 

0 0 

0 0 

0 0 

0 0 

0 0 

0 0

8 

8 

8

8 

8 

8 

8 

8 

8 

8 

8 

8 

10

0 ND 

0 ND 

0 ND

0 ND 

0 ND 

0 ND 

0 ND 

0 ND 

0 ND 

0 ND 

0 ND 

0 ND 

0 ND

0 

0 

0

0 

0 

0 

0 

0 

0 

0 

0 

0 

0

8 

12 

9

8 

9 

9 

9 

10 

10 

8 

10 

10 

11

0 0 .

0 Tr. 

0 Tr. 

0 0 .

0 13 

0 13 

0 13 

0 13 

0 Tr. 

0 Tr. .

0 13 

0 13 

0 0

0 

16

16 

16 

15 

16 

16

16 

16 

0

0 11 

0 11 

0 11

0 11 

0 10 

0 11 

0 9 

0 11 

0 11 

0 10 

0 9 

0 11 

0 13

>500 feet and <1 mile from known uranium deposit

239622...

238841-...

238850... .

238814... 

238815....

238816....

238817... .

QQQQ1Q

238836....

238837....

Chip channel. By road, west side Horse Mesa, 

Apache County, Ariz.

Joe Ben 3, San Juan County 

(unsurveyed) . 

.....do.. --.. NWJ£NEM sec. 33, T. 9 N., R. 5 W.,

Valencia County. 

....-do -----. Center SW sec. 22, T. 9 N., R. 5 W.,

Valencia County. 

Drill-hole Sec. 23, T. 13 N., B. 10 W., McKinley 

cuttings. County.

.-..do..--.--. SK}< sec. 30, T. 13 N., R. 9 W., McKinley County.

10 0 

9 0

8 0 

8 0 

8 0

8 0 

10 0 

8 0 

8 0 

8 0

8 0

0 .......

0 ND 

0 ND 

0 ND

0 ND 

0 ND 

0 ND 

0 ND 

0 ND

0 ND

0 0 

0 0

0 0 

0 0 

0 0

0 0 

0 0 

0 0 

0 0 

0 0

0 0

11 

9

9

8 

8

8 

8 

8 

8 

8

8

0 .......

0 .......

0 ND 

0 ND 

0 ND

0 ND 

0 ND 

0 ND 

0 ND 

0 ND

0 ND

0 

0

0 

0 

0

0 

0 

0 

0 

0

0

13 

10

11 

12 

11

11 

10 

11 

8 

11

9

0 0 

0 0

0 0 

0 0 

0 Tr.

0 Tr. 

0 0 

0 Tr. 

0 0 .

0 Tr. .

0 Tr.

0 

0

0 

0 

0

0 

0 

0

0

0 13

0 12

0 12 

0 10 

0 11

0 11 

0 11 

0 11 

0 10 

0 11

0 11

> 1 mile from known uranium deposit

239623. .. 

238838 

238820-..

238821... .

238822....

238843....

238812....

238813....

238824. __ 

238825....

238839...

252607. ._ 

252609....

Chip channel. South side Todilto Wash, Todilto 

Park, McKinley County (unsurveyed) . 

.....do --.-. NWM sec. 12, T. 15 N., R. 17 W., McKinley County. 

Grab. ._-__-. Inpit, center WJ-4WH sec. 17, T. 14 N.,

R. 12 W., McKinley County. 

.... .do --- . __ do _ .-. _- __ --_ . ___ ...

.-..do .-.. In pit, SE}<SE}<NW}<, sec. 28, T.

10 N., R. 9 W., Valencia County.

Chip channel. NW^SE}4 sec 4, T. 8 N., R. 5 W., 

Valencia County, 

.-.-do -.-- SWJ4 sec. 34, T. 9 N., R. 5 W., Valencia County. 

Grab--- Center SJSS^S^ sec. 14, T. 9 N.,

R. 5 W., Valencia County. 

Chip channel. NEJ£NWM sec. 7, T. 9 N., R. 4 W., 

Valencia County. 

..--.do. -. NE}<sec. 12, T. 9 N., R. 5 W., Valencia County.

9 0

9 ND

8 ND

8 ND 

9 ND 

8 ND 

9 ND

9 ND

9 ND

8 ND 

8 ND 

9 0 

9 0

0 ND 

0 ND

0 ND 

0 ND 

0 ND 

0 ND

0 ND 

0 ND

0 ND 

0 ND 

0 0 

0 0

0 0

0 0 

0 0

0 0 

0 0 

0 0 

0 0

0 0 

0 0

0 0 

0 0 

0 0 

0 0

10

11

8

8 

8 

8 

10

9 

10

9 

9 

10

8

0 .......

0 ND 

0 ND

0 ND 

0 ND 

0 ND 

0 ND

0 ND 

0 ND

0 ND 

0 ND 

0 0 

0 0

0

0 

0

0 

0 

0 

0

0 

0

0 

0 

0 

0

13

12 

12

12 

11 

12 

12

12 

12

12 

12 

13 

12

0 0

0 0 

0 0

0 0 

0 13 

0 Tr. 

0 0

0 0 

0 0

0 Tr. 

0 0 

0 0 

0 0

0

0 

0

0 

16 

0 

0

0 

0

0 

0 

0 

0

0 12

0 11 

0 11

0 11 

0 10 

0 11 

0 13

0 11 

0 13

0 12 

0 11 

0 0 

0 11

See footnote at end of table.
132 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

TABLE 11. Semiquantitative spectrographic, radiometric, and chemical analyses of samples of barren and uraniferous Todilto 

Limestone, northwestern New Mexico and northeastern Arizona Continued

Sample

Type of 

sample

Location

otherwise indicated. See pi. 3.)

Spectrographic ' Continued

Sr Sm Ta Tb Te Th Ti Tl Tm U V W Y Yb Zn Zr

>1 mile from known uranium deposit Continued

252610... 

252616. 

252614 

239624 

252611 .

246068--.

246070.-..

Chip channeL. 

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

. .do- -.-.

. do .

Chip channel . 

.--do. ...

. do ... .

. do ..

NE YH sec. 12, T. 9 N., R. 4 W., Valencia Cou ity. 

SWKsec. 13, T. 15 N., R. 1 E., Sandoval County. 

SWH sec. 13, T. 16 N., R. 1 W., (projected), Sandoval County. 

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

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

NWJ4 sec. 17, T. 23 N., R. 1 E., Rio 

Arriba County. 

NEKNWK sec. 8, T. 24 N., R. 4 E., 

Rio Arriba County. 

NEK sec. 25, T. 11 N., R. 5 E., Bernalillo County. 

SEK sec. 28, T. 25 N., R. 4 E., Rio 

Arriba County.

800 

900 

800

700 

700 

900

800 

900 

900

Radiometric

eTJ2 TJ3

Parts per million

0 0 

0 0 

0 0

0 0 

0 0 

.. 0

0 0 

 .... 0

.... 0

V2Oj or V*

0 9 

0 10

0 7

0 10 

0 10 

0 10

0 9 

0 9 

0 9

0 

0 

0

0 

0 

0

0 

0 

0

S 5 P2Q5 

Percent

0 0 

0 0 

0 0

0 0 

0 0 

..... .. 0

0 0 

... . 0

.---.. 0

Chemical

C^ 

(organic)

13 

12 

11

12 

12 

13

12 

11 

12

As «

0 0 

0 0 

0 13

0 0 

0 0 

0 0

0 0 

0 0 

0 0

F9

0 0 

0 0 

16 0

0 0 

0 0 

0 0

0 0 

0 0 

0 0

Se »» Zn

12 

12 

11

13 

13 

14

12 

12 

13

11

Parts per nillion

Mineralized ground

238805 

238810 

238840 

238847- . 

238849 .

Drill-hole, cuttings.

...._do ...-.

Chip channel . 

.... -do ....

SEK sec. 30, T. 13 N., R. 9 W., 

McKinley County.

NWKNW^NEK sec. 30, T. 13 N., R. 

9 W., McKinley County. 

SE^NEK sec. 4, T. 12 N., R. 9 W., 

Valencia County. 

SWKSWKSEK sec. 4, T. 12 N., R. 9 

W., Valencia County.

60 55 ND

10 9 ND

30 58 ND

50 58 ND 

1,300 1,600 ND

0.03

.05 

.05

.07 

.11

0.032

.029 

.020

.029 

.044

ND

ND

ND

ND 

ND

<5

<5 

<5

<5

50

100

120 

150

420 

240

2.0

1.0 

12.0

.5 

8.0

20 

10

> 25 feet and < 500 feet from known uranium deposit

238819- .

238848....

238806 

238809....

238828 

238829--.

238830..-.

238831 

238832....

238833.--.

238834 

238835--..

238823 

Drill-hole cuttings. 

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

.....do .....

 ..do 

.. do .

...-do -..-.

..... do 

-..-do. ..-.

.. do. .

 -do...... ...

 .do ._-...

 -.do. .

Chip channel .

SEKSEK sec. 23, T. 13 N., R. 10 W., 

McKinley County. 

SWKSWKSWK sec. 3, T. 12 N., R. 9 

W., Valencia County. 

SEJ4 sec. 30, T. 13 N., R. 9 W., 

Kinley County.

 do ... ....... 

 do. -.. .

.- do .... __ ._ . .

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

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

 do 

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

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

SWK sec. 8, T. 8 N., R. 5 W., Valencia 

County.

20

20

25 

10 

20 

30 

<10

<10 

10

12 ND 

8 ND 

19 ND

25 ND 

9 ND 

10 ND 

4 ND 

29 ND 

8 ND 

8 ND 

10 ND 

12 ND 

3 ND

0.09 

.07 

.05

.05 

.04 

.03 

.05 

.05 

.05 

.04 

.04 

.05 

.08

0.027 

.025 

.038

.035 

.033 

.037 

.044 

.030 

.035 

.038 

.038 

.033 

.024

ND 

ND

ND

ND 

ND 

ND 

ND 

ND 

ND 

ND 

ND 

NDND

<5

<5 

<5

<5 

5 

<5 

<5 

6 

6 

5 

6 

8 

<5

70 

660 

100

100 

70 

100 

150 

90 

90 

90 

60 

280 

170

0.5

<. 5 

2.0

'.5

1.0 

2.0

10 

20 

20 

30 

10 

10 

10

> 500 feet and < 1 mile from known nraninm deposit

239622 

246069--.

238841--.

238850--..

238814 

238815. -

238816- ._

238817.-.

238818...

238836 

238837...

Chip channel .

 .do ...

.. do 

Drill-hole cuttings. 

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

do

 -do ....

 -do- --.

.--.do- .-.

By road, westside Horse Mesa, Apache 

County, Ariz. 

Road cut ±1,000 feet northwest of Joe 

Ben 3, San Juan County (unsurveyed) . 

NW^NEK sec. 33, T. 9 N., R. 5 W., 

Valencia County. 

Center S^ sec. 22, T. 9 N., R. 5 W., 

Valencia County. 

Sec. 23, T. 13 N., R. 10 W., McKinley 

County. 

 ..do . 

.--do 

 do... _ __ _

_.-.do 

SEK sec. 30, T. 13 N., R. 9 W., 

Kinley County.

<100 

60

10 

10

10 

30 

<10 

<10 

20

9 ......---

60 <-0.05

4 ND 

14 ND 

5 ND

5 ND 

29 ND 

4 ND 

6 ND 

9 ND

24 ND

0.07 

.09

.02 

.07 

.06

.09 

.07 

.07 

.06 

.07

.07

0.017 

.030

.024 

.026 

.040

.038 

.036 

.035 

.039 

.039

.027

0.27 -.

.20

ND 

ND 

ND

ND 

ND 

ND 

ND 

ND

ND

24

<5 

<5 

<5

<5 

<5 

<5 

<5 

<5

<5

80 

130

120 

120 

140

220 

140 

140 

230 

110

130

<0.5 ...

1.0 

.5

io

'.5 

25.0

12.0

10

<10

<10 

30 

20

See footnotes at end of table.
DISTRIBUTION OF ELEMENTS IN THE ORES 133

TABLE 11. Semiquantitative spectrographic, radiometric, and chemical analyses of samples of barren and uraniferous Todilto Limestone

northwestern New Mexico and northeastern Arizona Continued

Sample

Type of 

sample

RadioLocation metric

Chemical

otherwise indicated. See pi. 3.) eU 2 U 3 v»Os or

V<

Parts per million

C' As 8 

S s PjOs » (organic)

Percent

F » Se »o Zn »

Parts per million

> 1 mile from known uranium deposit

239623... 

238838 

238820...

238821- ...

238822 

238843 

238812...

238813....

238824 

238825....

238839 

252607. _. 

252609--.

252610..-.

252616... .

252613 .

252614....

252615 

239624 

252611..-.

246068- ..

246070-.-.

Chip channel. 

.....do .

... ..do 

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

. -do..... .

 ._do_ -.-.

..-.do ...

Chip channel. 

.....do ....

Chip channel . 

... ..do ...

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

 . -do ... ...

.-..do .....

.....do ..

Grab. 

Chip channel.

...-do. .....

.....do. .

...--do ---.

South side Todilto Wash, Todilto <10 

Park, McKinley County (unsurveyed) . 

NWM sec. 12, T. 15 N., R. 17 W., <10 

McKinley County. 

In pit, center W^WW sec. 17, T. 14 N., <10 

R. 12 W., McKinley County.

In pit, SEMSEMNWJ4 sec. 28, T. 10 <10 

N, R. 9 W., Valencia County.

NWMSEM sec. 4, T. 8 N., R. 5 W., <10 

Valencia County. 

SWM sec. 34, T. 9 N., R. 5 W., Valencia <10 

County. 

Center SHS^SH sec. 14, T. 9 N., R. <10 

5 W., Valencia County. 

NE^NWM sec. 7, T. 9 N., R. 4 W., <10 

Valencia County. 

NEM sec 12, T. 9 N., R. 5 W., Valencia <10 

County.

SWM sec. 13, T. 15 N., R. 1 E., San- <10 

doval County. 

SWM sec. 13, T. 16 N., R. 1 W., (pro- <10 

jected), Sandoval County. 

.....do _-. ._ _--- <10

... ..do _ .- -__ .. 20

NWM sec. 17, T. 23 N., R. 1 E., Rio <10 

Arriba County. 

NE^NWM sec. 8, T. 24 N., R. 4 E., <10 

Rio Arriba County. 

NEM sec. 25, T. 11 N., R. 5 E., ND 

Bernalillo County. 

SEM sec. 28, T. 25 N., R. 4 E., Rio 20 ....

Arriba County.

1 

2

2 

6 

1 

4

2 

3

2 

2 

8 

3

5 

5

5

6 

4

3

6

ND 

ND

ND 

ND 

ND 

ND

ND 

ND

ND 

ND

<.05 

<.05

<.05 

<.05

<.05

<.05 

<.05

<.05 

«.001) 

<.05

0.07

.03 

.10

.05 

.05 

.06 

.07

.06 

.08

.10 

.06 

.11 

1.23

.21 

.38

.30

.40 

.19

.22

.84 

.98 

.45

0.017

.016 

.038

.038 

.033 

.037 

.019

.022 

.022

.030 

.031 

.018 

.048

.037 

.027

.029

.026 

.029 

.026

.033 

<.05 

.037

0.55 ..

ND

ND

ND 

ND 

ND 

ND

ND 

ND

ND 

ND 

<.3

.5

.6 

.9

.5

.9 

.9 

.40 ...

1.0 

.51 

1.59

<5 

<5

<5 

<5 

<5 

<5

<5

<5

<5 

<5 

30 

<5

<5 

<5

<5

<5

<5

<5

800

8

30 <. 5 

220 <. 5

200 <.5 

160 .5 

150 .5 

60 <.5

60 <.5 

70 <.5

90 2.0 

90 .5 

<20 1 

120 1

90 1 

80 .5

420 2

40 1 

40 2 

170 <. 5 -...

80 .5 

140 <1. 0 

230 <. 5

<10 

<10

<10 

<10 

10 

10

<10 

<10

30 

10 

9 

10

4 

18

10

14 

3

11 

14

6

1 Analysts; N. M. Conklin, sample 246068; R. G. Havens, samples 239622-239624, 

inclusive; all other samples by J. C. Hamilton.

2 Analysts: C. G. Angelo, samples 246069-246070 and 252607-252617, inclusive; all 

other samples by personnel under the general direction of L. F. Rader, Jr.

3 Analysts: -R. P. Cox, samples 252607-252617, inclusive; D. L. Ferguson, sample 

246068; H. H. Lipp, samples 246069 and 246070; all other samples by personnel under 

the general direction of L. F. Rader, Jr. Fluorimetric method.

4 Analysts: C. A. Horr, sample 246068; H. H. Lipp, samples 246069 and 246070; 

J. S. Wahlberg, samples 252607-252617, inclusive; all other samples by personnel 

under the general direction of L. F. Rader, Jr. Volumetric method.

5 Analysts: G. T. Burrow, samples 252607-252617, inclusive; C. A. Horr, sample 

246068; E. C. Mallory, samples 246069-246070 and 238805-238850, inclusive; all other 

samples by personnel under the general direction of L. F. Rader, Jr. Gravimetric 

method.

6 Analysts: D. L. Ferguson, samples 252607-252617, inclusive: L. F. Rader, Jr., 

samples 239622-239624, inclusive, and sample 246069; L. F. Rader, Jr., and H. H. Lipp, 

samples 238805-238850, inclusive; J. P. Schuch, samples 246068 and 246070. Volumetric 

method.

' C. A. Horr, sample 246068; Wayne Mountjoy, samples 246069-246070 and 242,607- 

252617, inclusive; all other samples by personnel under the general direction of L. F. 

Rader, Jr. Rapid scanning, CO2 method.

8 Analysts: C. A. Horr, sample 246068; Claude Huffman, samples 252607-2f2617 

and 238805-238850, inclusive; J. E. Wilson, samples 246069 and 246070. Colorinntric 

method.

» Analysts: R. P. Cox, samples 238805-238850 and 246068-246069, inclusive; W. D. 

Goss, samples 252607-252617, inclusive; all other samples by personnel under the 

general direction of L. F. Rader, Jr. Colorimetric method.

10 Analysts: G. T. Burrow, samples 246069-246070 and 252607-252617, inclusive; 

C. A. Horr, sample 246068; all other samples by personnel under the general direction 

of L. F. Rader, Jr. Colorimetric method.

n Analysts: G. T. Burrow and H. H. Lipp, samples 238805-238850, inclusive; 

C. A. Horr, sample 246068; Claude Huffman, samples 252607-252617, inclusive; J. S. 

Wahlberg samples 246069 and 246070. Colorimetric method.

The samples for the graphs of tables 12-14 are arranged in five groups or zones, ranging from the ore 

zone to a zone more than 1 mile from known uranium 

deposits. This outer zone is presumed to contain the 

average concentrations of uranium and other elements 

that were originally included in the host rock. The ore 

zone is represented by the mill pulp samples listed in 

table 6 and referred to in the preceding section. Samples representing the other four zones are listed 

in table 11. The mineralized zone is represented by 

samples taken within 25 feet of known limits of a 

mined ore body or within 25 feet of a sample containing at least 0.1 percent uranium. This rather narrow 

zone was selected to show significant changes in the 

immediate periphery of ore in what might be considered part of the uranium deposit. The other zones 

(>25 feet and <500 feet, >500 feet and <1 mile, and 

>1 mile from known uranium deposits) were selected 

rather arbitrarily to obtain as many sample zones between ore and nearly barren rock as possible. The number of such zones is limited by the number of samples 

taken. Obviously, the exact limiits of ore are rather 

indeterminate, and certainly not all uranium deposits 

or ore bodies were known when the samples were selected. Moreover, the limits of the three zones between 

ore and barren ground are rather sketchy because of 

the limited number of samples. Nevertheless, the sr,mple control should be adequate (see pi. 3) to show significant contrasts for most elements in the different

zones.
134 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

TABLE 12. Ranges of concentration and the geometric means of eight major elements in the ores and in four zone," away from

ore in the Todilto Limestone

[All analyses are spectrographic. Samples reported as >10 are assumed to be 15, which is the next higher number in the series 1.5, 3, 7]

Sample zone

>25 feet and <500 feet from

known uranium deposit .

>500 feet and <1 mile from

known uranium deposit .

> 1 mile from known uranium

deposit .... . ....

Ore. .

Mineralized ground

>25 feet and <500 feet from

known uranium deposit

>500 feet and <1 mile from

known uranium deposit . .

> 1 mile from known uranium

deposit. ... ...

vs

ll(O

131

25

313

411

522

31

5

13

11

22

Percent

O -* <O Is. Ift O

OOOOOOO«-i<Ors./\

1 1 1 1 1 1 1 1 1 1 1

SILICON (Si)

 \ 

 \-

 \ 

-\ 

ALUMINUM (Al)

_| ___ -h

 h

 1 

i i i i i i J i i i i

 *!

o|

(O

01

5

13

11

22

31

5

13

11

22

Percent

o « m is. m 3

OOOOOOOrH(Ors./\

1 1 1 1 1 1 1 1 1 1 1

IRON (Fe)

H1

H-

 1 

 h

MAGNESIUM (Mg)

-1-

4

H-

, , , , , ,nh , , ,

en *S«

IS(O

31

5

13

11

22

31(15)

5 (1)

13 (1)

11 (1)

22(12)

Percent

8SSBS «, 2

OOOOOOO^N rof^/X

1 1 1 1 1 1 1 1 1 1 ' 1

SODIUM (Na)

[i _

 |-

 ( 

 1 

POTASSIUM (K)

___J __

 h-

-H

-Hi i i i i 7~i~^T i i

^

ll

01

5

13

11

22

31

5

13

11

22

Percent

8S3B2r,.s.u, S

ooooocio^cnis.A

1 1 1 1 1 1 1 1 1 1 1

TITANIUM (Ti)

i

4-

-4

 |-

 1 

MANGANESE (Mn)

_j_

-1-

-h

 ji i i ' i i i i i i i i

1 Includes 8 samples reported as >10.

2 Includes 1 sample reported aa>10. 

^Includes 11 samples reported aa >10. 

4Includes 2 samples reported as >10.

5 Includes 1 sample reported aa >10.

6 Number in parentheses is the number of samples 

below the limit of detection.

EXPLANATION

r

Range in content of samples 

Dashed where uncertaii

pies >H 

in , I

Geometric mean of all samples 

in which element detected

The graphs show a few elements that progressively 

decrease in concentration outward from ore, a few that 

increase outward, and numerous elements that show a 

relatively high concentration in the three zones between ore and barren ground. (See tables 12-14).

ELEMENTS THAT DECREASE IN CONCENTRATION 

AWAY FROM ORE

Vanadium shows the most uniform or progressive 

decrease outward from ore, and somewhat similar relations are shown by selenium, zinc, arsenic, and lead. 

In many samples these elements were below the limits 

of detection in the outer zones, however, so the results 

are somewhat speculative. Selenium (table 14) occurs 

principally, and in relatively high concentrations, in 

the sulfide minerals in most uranium ores in the sedimentary rocks of the Colorado Plateau (Coleman and 

Delevaux, 1957). The relatively low content of selenium in the Todilto ores (table 6), therefore, probably 

reflects the low sulfide content of the ores and perhaps 

also the low content of volcanic debris in the Todilto. 

Such debris is the principal source to which Coleman 

and Delevaux (1957) ascribe the selenium in most of 

the deposits in the sedimentary rocks of the Colorado 

Plateau. About 45 percent of the samples tested for 

zinc, 75 percent tested for arsenic, and 88 percent tested 

for lead that were peripheral to ore contained less than 

detectable amounts, so the suggested outward decrease

of these elements away from ore is speculative. 

The discrepant graph for arsenic in the outer zone 

stems mostly from one sample (246068) that contained an anomalous 800 ppm. If this sample is disregarded, the mean concentration in the outer zone 

rather than being 12 ppm is 3.5 ppm, which is less 

than the maximum concentrations in the, other four 

zones.

ELEMENTS THAT INCREASE IN CONCENTRATION 

AWAY FROM ORE

Elements that show an increase in concentration 

outward from ore are magnesium (table 12), organic 

carton, sulfur (table 14), and possibly boron, cobalt, 

gallium, and ytterbium (table 13). Such relations for 

the latter four elements, however, are mere apparent 

than real because of the lower sensitivity of these elements in ore to spectrographic analysis and because 

in many samples from the other zones thase elements 

were below the limits of detection. The relations for 

magnesium are also rather uncertain because of the 

email range in median concentrations between zones. 

The relations of organic carbon deserve some comment, 

although the sample data pertain to only the ore zone 

and the two outermost zones away from ore.

Organic carbon in the form of carbonized plant 

debris is recognized as a precipitant or collector of 

uranium in many deposits in sandstone in the Colorado
DISTRIBUTION OF ELEMENTS EST THE ORES 135

TABLE 13. Ranges of concentrations and, the geometric means of IS minor elements in the ores and in four zones away from

ore in the Todilto Limestone

[All analyses are speetrographic. Numbers in parentheses are the number of samples below the limit of detection.]

Sample zone

Ore

Mineralized ground

>25 feet and <500 feet from

known uranium deposit .

>500 feet and <1 mile from

known uranium deposit ....

>1 mile from known uranium

deposit . .

Ore

Mineralized ground .

>25 feet and <500 feet from

known uranium deposit . .

>500 feet and <1 mile from

known uranium deposit . .

>1 mile from known uranium

deposit ....

Ore .

Mineralized ground .

> 25) feet and <500 feet from

known uranium deposit

>500 feet and <1 mile from

known uranium deposit

>1 mile from known uranium

deposit ,' . .

Ore .

Mineralized ground . . . . ....

>25 feet and <500 feet from 

known uranium deposit

>500 feet and <1 mile from 

known uranium deposit

>l mile from known uranium

deposit

Ore . 

Mineralized ground

>25 feet and <500 feet from

known uranium deposit .

>500 feet and <1 mile from

known uranium deposit

> 1 mile from known uranium

deposit . ....

*= "§, 

o 5

^ 1

Percent

Illo SB S cnr-u,

§§§§§§§§83oo2m

oooooooooooooo

1 1 ! BORON (B)

131 (31)

5 (5)

213 (4)

11(11)

322 (20)

-0 -0

 o

-H

-0

-H

BARIUM (Ba)

31

5

13

11

22

 1 

1

 1 

 1 

 1 

COBALT (Co)

31 (4)

5 (4)

13 (11)

11 (10)

22 (20)

-+- 1

 1

 1

 -1

CHROMIUM (Cr)

31

5

13

11

22

 I 

 1 

+

-h

-h

COPPER (Cu)

31

5

13

11

22

+

 1 

-j 

1 1 1 1 1 1 'l 1 J_ 1 1 1 J 1

0 

£ a

Percent

1 iiss os m ^«

§§§§§§§§8ooo2m

oooooooooooooo

1 1 1 < 1 1 1 1 1 GALLIUM (Ga)

31 (31)

4 5 (1)

513 (1)

611 (3)

722 (17)

-o

-H

--I

-1

-1

MOLYBDENUM (Mo)

31 (17)

5 (5)

13 (13)

11 (H)

22 (22)

 1 

-0

-O

- O

-0

NICKEL (Ni)

31

5 (1)

813

11 (U

822 (7)

H-

-1

-t-

--I-

 1-

"= §,

0 g

fc 3CD

Percent

|| g S m B2 m ,.«

§§§§§§§§8ooo2m

oooooooooooooo

I I I i : 1 1 1 1 YTTRIUM (Y)

1131 (26)

9 5 (4)

1213 (3)

1311 (6)

1122 (18)

 i

--H

 1-

-H

 i

YTTERBIUM (Yb)

30(30)

2 (2)

10 (2)

9 O)

22 (20)

-0 -0

-0

- h

-0

 1

ZIRCONIUM (Zr)

31

5

13

11

22 (1)

 1 

 1 

 1 

 1 

i i i i i ~ i r ii i i i i

LEAD (Pb)

31

»5 (2)

1013 (6)

911 (9)

1122 (19)

__ |_ EXPLANATION

 | 

r 

Range in content of samples *H 

Dashed where uncertain j

 | 

 Geometric mean of all samples 

 ~T reported as trace or more

"4

STRONTIUM (Sr) Approximate limit of sensitivity where the

31

5

13

11

22

 T- -0 -0

Approximate limits of sensitivities where

 1 they vary between samples. All samples

undetected and below either or both

 [ limits

i i i i L i i i i i i "i r i

1 Six samples reported as <0.05; others undetected and presumably <0.002.

2 Nine samples reported as trace, assumed to be 0.002.

3 Two samples reported as trace, assumed to be 0.002.

4 Eight samples reported as trace, assumed to be 0.0002.

5 Twelve samples reported as trace, assumed to be 0.0002.

6 Eight samples reported as trace, assumed to be 0.0002.

7 Five samples reported as trace, assumed to be 0.0002.

Plateau, and sedimentary rocks containing an abundance of such material are considered favorable hosts 

for uranium deposits. Since the time commercial uranium deposits were discovered in the Todilto Limestone 

there has been much speculation about the influence 

the carbonaceous content of the limestone had on emplacement of the deposits. This speculation was nourished by the dark-gray or nearly black color and the 

fetid odor emitted by the limestone when crushed. 

These facts led many to refer to it as petroliferous and 

thus to consider it carbonaceous.

8 Includes 1 sample reported as trace and assumed to be 0.0003.

9 Includes 1 sample reported as trace and assumed to be 0.001.

10 Includes 6 samples reported as trace and assumed to be 0.001.

11 Includes 2 samples reported as trace and assumed to be 0.001.

12 Includes 4 samples reported as trace and assumed to be 0.001.

13 Five samples reported as trace, assumed to be 0.001.

As a help in clarification of this problem, all samples 

were analyzed for organic carbon. Unfortunately, 

the method used to analyze the first samples was not 

accurate enough to determine their content, so there 

are no data for the two zones near ore, and there are 

data for only two samples from the zone that is > 500 

feet and <1 mile from uranium deposits. The results, 

however, show a much lower organic carbon content 

in ore than in each of the two outermost zones (table 

14). This contrast is even more striking when the 

range in concentration for organic carbon in or0, is
136 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

TABLE 14. Ranges of concentration and the geometric means of uranium, vanadium, sulfur, phosphate, organic 

caroon, arsenic, fluorine, selenium, and zinc, in the ores and in four zones away from ore in the Todttto

Limestone

[All analyses are chemical except for vanadium, as noted]

Sample zone

Ore 

Mineralized ground 

>25 feet and <500 feet from 

known uranium deposit 

>500 feet and <1 mile from 

known uranium deposit 

>1 mile from known uranium 

deposit

Ore 

Mineralized ground 

>25 feet and <500 feet from 

known uranium deposit 

>500 feet and < 1 mile from 

known uranium deposit 

> 1 mile from known uranium 

deposit

Ore 

Mineralized ground . 

>25 feet and <500 feet from 

known uranium deposit 

>500 feet and < 1 mile from 

known uranium deposit 

>1 mile from known uranium 

deposit

Ore 

Mineralized ground 

>25 feet and <500 feet from 

known uranium deposit 

>500 feet and < 1 mile from 

known uranium deposit 

>1 mile from known uranium 

deppsit

Ore 

Mineralized ground 

>25 feet and <500 feet from 

known uranium deposit 

>500 feet and < 1 mile from 

known uranium deposit 

>1 mile from known uranium 

deposit

*!

£|

Percent

§ S 2 8

o d o 

. . . , , . I , ....... I , ....... 1 . ,,..,,, 1 URANIUM (U)

31 

5

13 

11 

21

 | 

 | 

 1 

 | 

 1 

VANADIUM (V) 1

31 

5

13

^

22

25 

5

13 

11 

22

 1 

 | 

 | 

 | 

 1 

SULFUR (S)

 1 

 1 

 h-

 | 

PHOSPHATE (P2 05 )

31 

5

13 

11 

222 (1)

 1 ;

ORGANIC CARBON (C)

24

0

0 

2

312

 \ 

No data 

No data

-1-

,,,,,, i , , , , , , , , i , ,,,,,,, i , . ~ , , ! , , i ,

Sample data are spectrographic, except for ore samples which are chemical 

and assay 0.10 percent or more Vo O5 ; these are converted from Vo Oj to V.

2Number in parentheses is number of samples below limit of detection and not 

used.

'Includes 1 sample reported as <0.3 and assumed to be 0.2 percent.

4 Includes 4 samples reported as <5 and assumed to be 3 ppm.

5Includes 7 samples reported as <5 and assumed to be 3 ppm.

includes 9 samples reported as <5 and assumed to be 3 ppm.

'Includes 17 samples reported as <5 and assumed to be 3 ppm.

'Includes 1 sample reported as <20 and assumed to be 10 ppm.

'Includes 8 samples reported as <0.5 and assumed to be 0.3 ppm.

10 Includes 5 samples reported as <0.5 and assumed to be 0.3 ppm.

"Includes 8 samples reported as <0.5 and assumed to be C.3 ppm; 

and 1 sample reported as < 1.0 and assumed to be 0.5 ppm.

12 Includes 3 samples reported as <10 and assumed to be 5 ppm.

13 Includes 6 samples reported as < 10 and assumed to be 5 ppm.

"Includes 6 samples reported as <10 and assumed to be 5 ppm; 

and 1 sample reported as <1 and assumed to be 0.5 ppm.

only from 0.05 to 0.14 percent when sample 246891 is 

disregarded. (See table 6.) This sample represents a deposit that contained less than 0.1 percent U3O8 .

The low organic carbon content in the ore can be 

explained by (1) the removal of organic carbon from 

the sites of deposition by the ore-bearing solutions, 

(2) the ore favoring the limestone where it is deficient 

in organic carbon, or (3) simply a fortuitous relation. 

The favored explanation is that organic carbon was 

»-emoved during emplacement of the deposits. There is

no apparent reason why the ores should select the 

rocks that were deficient in organic carbon and there 

is no reason to believe that the indicated relations are 

fortuitous. Removal of carbon from the sites of deposition, therefore, seems reasonable, perhaps as a result 

of oxidation. It is doubtful that concentrations of organic carbon caused localization of the uranium deposits, but the organic carbon may havns caused precipitation of the uranium at favorable structural sites 

by reducing the uranyl ion and by precipitating the
DISTRIBUTION OF ELEMENTS IN THE ORES 137

TABLE 14. Ranges of concentration and the geometric means of uranium, vanadium, sulfur, phosphate, organic carbon, arsenic, 

fluorine, selenium, and zinc, in the ores and in four zones away from ore in the Todilto Limestone Continued

Sample zone

Ore 

Mineralized ground 

>25 feet and <500 feet from 

known uranium deposit 

>500 feet and <1 mile from 

known uranium deposit 

>1 mile from known uranium 

deposit

Ore 

Mineralized ground 

>25 feet and <500 feet from 

known uranium deposit 

>500 feet and <1 mile from 

known uranium deposit 

>1 mile from known uranium 

deposit

Ore 

Mineralized ground 

>25 feet and <500 feet from 

known uranium deposit 

>500 feet and <l mile from 

known uranium deposit 

>1 mile from known uranium 

deposit

Ore 

Mineralized ground 

>25 feet and <500 feet from 

known uranium deposit 

>500 feet and < 1 mile from 

known uranium deposit 

>1 mile from known uranium 

deposit

<«8 °& 

*§

31 

45

513

610 

'20

Parts per million

-i 0 0 0

- 2

. . . . , . 1 , ,,,..., 1 . ,,,,,,,! . ,..,,., 1 ARSENIC (As)

 | 

" 1- 

-4 

 1| _ __

FLUORINE (F)

31 

5

13 

11 

822

31 

5

913

ion 

1122

 | 

 | 

 | 

SELENIUM (Se)

 | 

 | 

 1 

 1 

 H 

ZINC (Zn)

31

125

1313 

»10 

320

 I 

i

i

 __l 

 | 

. . i , , , i , . ! !""! ... i . ,,,..,. i . .,,,.., i

EXPLANATION

-Range in content of samplesDashed where uncertain

Geometric mean of all samples, 

except where noted

uranium in pitchblende. Apparently enough organic 

carbon is present to cause such reduction, provided it 

is in a form that is as effective a reducing agent as 

lignite (Garrels and Pommer, 1959, p. 163-164; and 

table 3).

Sulfur shows about the same range in concentration 

and mean concentration for each of the four inner 

zones. The outer or barren zone shows a much greater 

range in concentration and a mean concentration 

which is about three times that of each of the other 

zones. These differences may not have any significance 

as far as uranium is concerned because they probably 

are mostly a reflection of differences in the sulfate 

content of the host rock in different areas; the analyses represent the sulfur in both sulfides and sulfates. 

Relatively high concentrations of gypsum and anhydrite, particularly along the east side of the San Juan 

Basin, could account for the relatively high sulfur

content in the outer zone. Moreover, the outer zone 

shows no attendant increase in iron content, wlich 

would be expected if the sulfur occurred in the suHde 

pyrite.

ELEMENTS CONCENTRATED BETWEEN OBE AFD 

BABBEN GROUND

Elements that have a relatively high concentration 

between ore and barren ground are silicon, iron, sodium, titanium, aluminum, manganese, and potassium 

(table 12), chromium and zirconium (table 13), and 

phosphorus (shown as phosphate) and fluorine (t^.ble 

14). Many of these elements are major constituent? of 

the host rock, and such an original arrangement would 

hardly be expected especially in a rather monolithic 

host like the Todilto. The simplest explanation for 

the arrangement is that many of the constituents of 

the host rock were leached from the sites of the ore 

bodies and redeposited in their periphery at the time
138 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

TABLE 15. Semiquantitative spectrographic, radiometric, and chemical analyses of gypsum and limy gypsum from the Toiilto Limestone>

northwestern New Mexico

Semiquantitative spectrographic determinations were made by the rapid visual-comparison method. Comparisons of similar data with those obtained by qrantitative methods

show that the assigned Semiquantitative class interval includes the quantitative value in about 60 percent of the determinations. 

The following elements were looked for but not found: Ag, As, Au, B, Be, Bi, Cd, Co, Cr, Dy, Er, Eu, Ga, Gd, Ge, Hf, Hg, Ho, In, IT, K, La, Li, Lu, Mo, Nb, Ni, Os, P,

Pb, Pd, Pt, Re, Rh, Ru, Sb, Sc, Sm, Sn, Ta, Tb, Te, Th, Tl, Tm, U, W, Y, Yb, Zn, and Zr. Also, Cs, F, Pr, and Rb were not looked for. O, looked1 for but not found;

>, greater than amount shown; <, less than amount shown, standard detectability does not apply.

[Analyses are in percent, except as otherwise indicated]

Type of 

Sample sample

Location (see pi. 3) Spectrographic'

County Sec. T. R. Al Ba Ca Ce Cr Cu Fe Mg Mn Na Nd Si Sr Ti

252608--. Chunk...- Valencia.. NWM12- 9 N. 5 W. 

252612... .--..do.. Rio Arriba. NE^NW^ 8 24 N. 4 E.

252617-. Chip Sandoval- SW>£13 .. 15 N. IE. 

channel.

.015 0.0007 >10 <0.05 0 

.015 .0007 >10 <. 05 0

0.00015 0.007 0.015 0.0007 0

.00015 .007 .015 .0015 0

<0.02 0.07 0.03 0.0003 0.0015 

<.02 .03 .03 .0003 .0015

.03 .0003 >10 <.05 .00015 .0003 .007 .015 .003 .07 0 .3 .03 .0015 .0015

Sample

252608 ...

Type of -

sample

Chunk. 

Location (see pi. 3) Radiometric

County

Valencia -. NW^12_ 9N. 5W.

eTJ2 TJ3 V2O5<

Parts per million

<10 3 <0. 05

Chemical

S s P205 e

Percent

17. 8 <0. 003

Ci

(organic)

<0.3

As 8 F 9 Se 5 Zn s

Part"? per million

<5 <20 <0. 5 <1

252612.------do..... Rio NE^NWM 24 N. 4 E.

Arriba. 8.

252617 Chip Sandoval- SWM13 - 15N. 1 E. 

channel.

<. 05 

<.05

17.3

13.7

<.003 

.004

<5 

<5

<20 

30

1 Analyst: J. C. Hamilton.

2 Analyst: C. G. Angelo.

3 Analyst: R. P. Cox. 

* Analyst: J. S. Wahlberg. 

8 Analyst: G. T. Burrow.

e Analyst: D. L. Ferguson.

7 Analyst: Wayne Mountjoy.

8 Analyst: Claude Huffman. 

'Analyst: W. D. Goss.

of uranium mineralization. A lack of detailed sample 

control precludes nraking any estimate of the quantity 

of the materials removed and redeposited or determining the size and shape of the affected zones. Phosphorus and fluorine, however, deserve further comment 

because of their possible bearing on localization of the 

deposits.

In some sediments the phosphatic mineral fluorapatite may contain uranium in concentrations as high 

as about 1 percent (Altschuler and others, 1958, p. 50- 

51). Thus, the phosphate content in the limestone unit 

of the Todilto was determined to find the role fluorapatite might have played in the presence of the uranium 

deposits. The results show that the phosphate content 

of the limestone is quite low and is actually lowest in 

ore, where it has a median concentration of only 0.007 

percent. Obviously, any fluorapatite in the Todilto 

could contain only a minute part of the uranium 

present in the rock. For this reason, and because the 

phosphate content is lowest in ore, conclusions are 

that the phosphate had no influence on localization of 

the deposits.

Local spotty concentrations of fluorite in some deposits and of rather finely disseminated, but conspicuous, fluorite in others in the Todilto have led to 

much speculation about the origin of the fluorite and 

its bearing on the source of the ore-bearing solutions. 

If the fluorite was largely derived externally, such as 

magmatically, it should show a relatively high concentration in the ores. The analytical results, however, do not support this assumption. In fact, the 

geometric means of the five zones show a narrow 

range from 90 to 180 ppm fluorine, and the mean content in the ores is only about 100 ppm fHorine. Actually, the mean concentration in each of the zones is no 

more than might be expected originally in limestone, 

of which fluorine and fluorite are common constituents 

(Goldschmidt, 1954, p. 579).

The ore samples show a range in concentration of 

fluorine of from 20 to 1,700 ppm, but only two samples contained more than 500 ppm (tab1 *} 6). Bather 

than make a special case and imply amagmaticorigin 

for these relatively high concentrations, it seems more 

reasonable to explain them as a rearrangement of the 

fluorine in the host rock (Goldschmidt, 1954, p. 574).

ELEMENTS IN THE GYPSUM UNIT 

Although uranium deposits have not b^n found or 

anticipated in the gypsum unit of the Todilto Limestone, three samples (252608, 252612, 252617) were 

selected from three widely separated localities (pi. 3) 

to determine whether the gypsum contained any unusual elemental concentration that might have some 

bearing on the localization of the deposits in the limestone unit. The results, as shown in table 15, show 

nothing unusual. Somewhat higher values shown for 

some metals and fluorine in sample 252617 are most 

likely a reflection of a somewhat higher content of 

limestone than for the other two samples.
DISTRIBUTION OF ELEMENTS IN THE ORES 139

SUMMARY AND CONCLUSIONS

The distribution of elements in the limestone unit of 

the Todilto Limestone shows a zonal decrease for vanadium and selenium outward from ore and probably a 

similar distribution for arsenic, lead, and zinc. Elements that show an increase outward from ore are 

organic carbon and probably magnesium. The increase 

of sulfur is most likely the result of the relatively high 

sulfate in the outer zones caused by a regional increase 

of gypsum in the eastern part of the Todilto basin.

Many elements show a relatively high concentration 

in the zones between ore and barren ground. These are 

principally major rock constituents and include silicon, iron, sodium, titanium, aluminum, manganese, 

potassium, chromium, zirconium, phosphorus, and 

fluorine. The arrangement of this assemblage is most 

likely the result of a rearrangement of the original 

constituents of the host rock by the mineralizing 

solutions.

The low content of selenium, relative to other uraniferous host rocks in northwestern New Mexico and the 

Colorado Plateau, probably reflects a low sulfide content in the ores and a low content of volcanic debris in 

the host rock. The low phosphate content indicates 

the presence of little if any fluorapatite; it also indicates that the phosphate, in turn, had little if any influence on localization of the uranium deposits. The low 

content of organic carbon in the ores and the relatively 

high content in barren rock indicates that the carbon 

likewise had no significant influence on localization of 

the deposits but may have caused precipitation of 

uranium at favorable structural sites.

Fluorine occurs in the ores and in the host rock in 

concentrations that are considered normal for limestone, and some local relatively high concentrations 

probably are the result of rearrangement within the 

host rocks by mineralizing solutions.

Nothing in the concentrations or distribution of the 

various elements indicates that the gypsum-anhydrite 

unit, or the content of such material in the limestone 

unit, influenced the localization of the uranium deposits. Likewise, nothing could be determined in the 

limestone unit that could have influenced the localization of the deposits. As a corollary, the zonal concentrations of the various elements offer little help in 

broadly classifying the ground for uranium potential. 

The zonal relations of some of the elements, however, 

should be helpful in guiding exploration within a 

mile or less of deposits. In addition to uranium, which 

is the most readily detectable of the elements, vanadium and, less certainly, selenium, zinc, and lead 

should be useful guides because of their direct relation

329-381 O 69 10

to uranium concentrations. Indirectly, organic carbon 

might also be useful, but more data on the zones ne<\r 

ore are needed to be certain of the relations.

The outer limit of detection of anomalous amounts 

of these elements appears to be somewhere between 

500 feet and 1 mile from known ore deposits. Because 

of the ranges in concentration among samples, the 

mean concentration of several samples obviourTy 

should be more reliable and effective than the concentration in single samples. Likewise, the collective 

use of the concentrations of several elements is more 

meaningful than the concentration of one element.

AGES OF EMPLACEMENT

The uranium deposits occur in many formations of 

various lithologies and ages and under various structural conditions in the respective districts and areas. 

A review of the ages of emplacement and the general geologic relations that bear on them for the peneconcordant and vein deposits will be helpful in evaluating the resources and establishing guides to ore.

Penecoiicordant deposits, by their probable ages of 

emplacement, can be grouped in three categories: (1) 

those in Pennsylvania!!, Permian, and Triassic rocks;

(2) those in Jurassic- and some Cretaceous rocks; and

(3) those in Tertiary and Quaternary rocks. Deposits 

in the first category are tentatively considered to have 

been emplaced in Pennsylvanian to Lake Triassic 

time; those in the second, in Late Jurassic to early 

Tertiary time; and those in the third, in mid-Tertir,ry 

to Recent time.

Age of emplacement of deposits in Pennsylvanian, 

Permian, and Triassic rocks in highly tentative. The 

earliest tectonic events that may have influenced the 

emplacement were uplift of the San Luis, Zuni, and 

Joyita highlands in late Paleozoic time; Late Permian and Early Triassic deformation and beveling of 

the highlands; and subsequent up wrap of the San 

Luis highland and highlands to the south and southeast in later Triassic time. Deposits occur in arko^ic 

debris shed from these highlands and incorporated 

into rocks of Pennsylvanian, Permian, and Triassic 

ages, but the detailed structural relations are not

& "

known. Most deposits, however, occur along or near 

the margins of the old depositional basins, similar to 

the mode of occurrence of the principal deposits in 

the Jurassic and Cretaceous rocks. Because the latter 

deposits probably were emplaced during initial deformation of the basins of deposition, the assumption 

seems plausible that the deposits in the Pennsyrranian to Triassic rocks experienced a similar but earlier 

history.
140 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

Deposits in rocks of Jurassic and Cretaceous age 

initially were emplaced in Late Jurassic to early Tertiary time, and probably the principal primary mineralization occurred in pre-Tertiary time. The deposits are no older than Late Jurassic because they occur 

in intraformational folds in the Todilto Limestone 

and in sandstone pipes that formed during Late Jurassic deformation. They are older than the earliest 

fracturing that is correlated with the McCartys syncline and the early development' of the monoclinal 

folds 011 the flanks of the San Juan Basin. This 

folding occurred principally during the initial deepening of the basin in Paleocene time, so the deposits 

must have been emplaced at least by Paleocene time 

to precede the fracturing. Some evidence, however, 

suggests that they were earlier, and that the deposits 

in the Cretaceous rocks possibly were emplaced after 

the ones in the Jurassic rocks.

In the Laguna district, for example, where Moench 

(in Hilpert and Moench, 1960, p. 458) has demonstrated control of the deposits in the Todilto Limestone and Entrada Sandstone by pre-Dakota folds, 

the deposits transect the formational boundary across 

the steep flank and anticlinal and synclinal bends of a 

monocline. The folding is interpreted to have occured 

shortly after deposition of the limestone, because the 

limestone is markedly thicker in the synclinal trough 

than on the flank and probably resulted from flowage 

during folding, prior to consolidation. Moench (1963c, 

p. 163-164) interpreted the emplacement of the deposits to have occurred during folding, because the deposits are controlled by the fold but dip toward the 

trough of the fold at a lower angle than the host 

formations. These data suggest that the deposits were 

emplaced prior to consolidation of the host rocks, 

probably in Late Jurassic time.

Deposits in the Morrison Formation also probably 

were emplaced in Late Jurassic time, but later than 

the deposits in the Todilto. Some of the Morrison 

deposits were emplaced in sandstone pipes. Because the 

pipes are the same age as the enclosing sedimentary 

rocks, the deposits must be Morrison in age or younger. 

It is doubtful that they are much younger, however, 

and most likely they are pre-Dakota in age. None of 

the primary deposits in the Morrison are known to 

transect the Morrisoii-Dakota contact, and some data 

suggest that such deposits locally are beveled under 

the pre-Dakota erosion surface (Kittel, 19G3, fig. 4). 

It is concluded, therefore, that the deposits in the 

Morrison also are Late Jurassic in age, but younger 

than the ones in the Todilto. If the deposits in the 

Todilto Limestone and Morrison Formation were 

emplaced in Late Jurassic time, as these data suggest,

the deposits in the Dakota Sandstone, v^hich is Cretaceous in age, must be younger.

The earliest that such emplacement ir the Dakota 

Sandstone could have taken place would have been 

Early Cretaceous and would likely have- occurred in 

the southwestern part of the area; it is in this area that 

the Dakota may be partly Early Cretaceous in age 

probably older than elsewhere. (See p. 21.) In the 

southwestern part of the Gallup district, the black ore 

in the Diamond 2 mine was apparently emplaced 

after slumps formed at the base of the Dakota and 

prior to fracturing. If the fracturing formed in Paleocene time, the age of emplacement of tH ore would 

have been restricted to Early Cretaceous to Paleocene. 

Again, where evidence can be found to date the earliest mineralization, ore minerals are fo^nd in association with structural flowage features that must 

have formed shortly after the rocks were deposited, 

a relation that is similar to the one in the Todilto 

Limestone and Morrison Formation. Tl Q- data suggest, therefore, that the primary deposits in the Jurassic and Cretaceous rocks were emplaced in Late 

Jurassic time and Cretaceous to Paleocene time, 

respectively.

Deposits in rocks of Tertiary and Quaternary ages 

probably were emplaced in mid-Tertiary time or later, 

but the evidence is mostly indirect; som^ could have 

formed as early as Paleocene. The younge^ age is favored for most of them because of the more intensive 

tectonism in mid-Tertiary time and later. The older 

age is speculative because most of the deposits are surficial, are associated with fractures, and are highly 

oxidized. The mid-Tertiary to Kecent tectonism more 

or less climaxed deformation that was intermittent 

throughout Tertiary time; this tectonisn caused the 

development of the Galisteo basin in early Eocene 

time, the deepening and northward tilting of the San 

Juan Basin, the southward tilting of the Datil Mountains area, and the widespread fracturing that culminated in development of the Kio Grande trough. During this deformation, dioritic and monzonitic rocks 

were intruded, most likely in early to middle Tertiary 

time, and rather extensive volcanism occurred throughout the rest of Tertiary and Quaternary time. Few 

deposits show an obvious relation to structural features formed during this period except for the secondary minerals which are controlled by fractures. A 

few deposits, as in the Baca and Galisteo Formations, 

are unoxidized at the outcrop but are in highly carbonaceous material. None show any obvious relation to 

the intrusive igneous rocks. Conclusions are that most 

deposits probably are mid-Tertiary or yonnger in age, 

but some may be as old as Paleocene.
DISTRIBUTION OF ELEMENTS IN THE ORES 141

Vein deposits were emplaced during four periods: 

(1) Precambrian, (2) Late Jurassic to early Tertiary, 

(3) early Tertiary, and (4) mid-Tertiary to Recent.

During the Precambrian, vein deposits in metamorphic rocks and in pegmatite bodies were formed. 

The deposits are considered to be Precambrian in age 

because of their association with the Precambrian 

Tusas Granite (Just, 1937; Jahns, 1946). Deposits in 

sandstone pipes in the Morrison Formation were emplaced contemporaneously with the peneconcordant 

deposits in the same rocks, probably during the late 

Jurassic. During the third period, probably in Oligocene time, the La Bajada deposit was emplaced in 

the Espinaso Volcanics of Stearns (1943). Probably at 

the same time the monzonitic bodies and base-metal deposits, similar to the La Bajada deposit, were emplaced 

in the Los Cerrillos and Ortiz Mountain districts. 

During the fourth period, most of the deposits along 

faults in miscellaneous sedimentary rocks and in 

fractures in igneous rocks along the Rio Grande 

trough were formed. The ages of most of these deposits probably are young, similar to those of the peneconcordant deposits in rocks of Tertiary and Quaternary ages. Faults in the Rio Grande trough formed during the development of the trough, so are Miocene(?) 

or younger. Deposits associated with faults therefore 

also are Miocene(?) or younger. Most of the deposits 

bottom within a few tens of feet below the surface and 

are largely made up of oxidized minerals, mainly yellow and green uranyl validates and phosphates. Thus, 

they appear to be surficial, similar to many of the 

peneconcordant deposits in the Tertiary and younger 

rocks, and probably are Quaternary or Recent in age. 

Most of the vein deposits in igneous rocks also contain 

surficial oxides and probably are Recent in age, 

although some of them could be remnants of older 

primary deposits; a few, such as the Cerro Colorado, 

may be related to volcanism and would therefore be 

somewhat older.

In conclusion, the emplacement of the uranium 

deposits in northwestern New Mexico can be grouped 

into five different ages: (1) Precambrian, (2) lajte 

Paleozoic to Late Triassic, (3) Late Jurassic to early 

Tertiary, (4) early Tertiary, and (5) mid-Tertiary to 

Recent. Peneconcordant deposits may be referred to 

the second, third, and fifth ages, and vein deposits 

may be referred to the first, fourth, and fifth ages. 

Vein deposits that formed during the third age in 

sandstone pipes in the Morrison Formation are the 

same age as the peneconcordant deposits that formed 

in the Morrison. These deposits were formed at about 

the same time as the peneconcordant deposits in the 

Todilto Limestone, probably during the Late Jurassic. Peneconcordant deposits in the Dakota Sandstone 

and in some other Cretaceous rocks were formed later, 

but locally may be as old as Early Cretaceous. Peneconcordant deposits in Tertiary and Quaternary 

rocks, and vein deposits along faults in various sedimentary rocks and in fractures in most igneous rocks, 

were nearly all formed during the fifth age. Many of 

them probably are Recent.

GEOLOGIC CONTROLS

The foregoing sections indicate that the deposits 8,re 

related to, or controlled by, various lithologic, stratigraphic, and structural features. As an aid to resource 

appraisal and a guide to exploration, the broader and 

more important of these features that affect peneccncordant and vein deposits are summarized.

Peiieconcordaiit deposits occur in sandstone, limestone, and shale and coal. Of these, the ones in sandstone are most important economically because of size 

and abundance. The host sandstones have similar lithologic, sedimentary, and structural characteristics. 

They mostly are medium- to coarse-grained crossbedd^d 

arkoses that are carbonaceous and contain volcanic 

debris. Cut-and-fill structural features, including mudstone lenses, interstitial clay, and high-angle cro?sbedding, indicate a fluvial environment. The sardstones are thicker and more concentrated along the 

margins of depositional basins and generally comprise a complex of discontinuous channel sands. In 

the Morrison Formation they locally are abnormally 

thick in structural depressions along the margins of 

and within the sedimentary basin. These depressions 

and their contained sandstone units range from several miles to several tens of miles in width and length. 

The principal uranium deposits occur in the central 

parts of the sandstone masses that occupy these 

troughs in the Laguna, Ambrosia Lake, Chuska, and 

Shiprock districts, where the sandstone masses range 

in thickness from about 200 feet to more than 500 feat. 

Host sandstone lenses within the masses generally ?,re 

30 feet or more thick.

In the Dakota Sandstone the principal deposits 

occur at the base of the formation in channel sards 

that range in thickness from 20 to 50 feet at the 

center and in width from 300 to 800 feet. Little is 

known of their lengths, as they have been explored 

only a few hundred feet back from outcrop.

Within the host sandstones, deposits are controlled 

in detail by miscellaneous sedimentary structures and 

concentrations of carbonaceous matter, which hfve 

been widely described and need not be itemized. They 

also are controlled by tectonic structures, indirectly 

and directly.
142 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

Indirectly, the deposits are controlled by the sedimentary basins that received the host sandstones and 

by subsidiary structural features along the flanks and 

within the basins. Most important of these basins was 

the old Jurassic basin. The segment of this basin that 

is represented in northwestern New Mexico, largely 

within the San Juan Basin, has remained in large 

part as a closed structure since its inception. All the 

other basins have been breached, a factor that could 

either have influenced the nondeposition of deposits 

or have permitted their leaching and removal after 

formation.

Important subsidiary structural features that indirectly controlled deposits are the Late Jurassic 

troughs, depressions, and folds in the Morrison Formation. These features controlled the thickness and 

trends of the host sandstone units during deposition 

and may have caused thinning of the host sands over 

domes such as the Ambrosia and San Mateo domes.

More directly, anticlinal and synclinal folds of this 

age locally may also have partly controlled some 

deposits, such as the Jackpile in the Laguna district. 

Monoclinal folds of Cretaceous age or early Tertiary 

age possibly partly controlled some deposits in the 

Dakota Sandstone and in some of the other Cretaceous 

formations.

Fractures directly control many deposits, but mostly 

the deposits that are oxidized. Most important are the 

fracture sets of Late Cretaceous to early Tertiary age 

in the Ambrosia Lake district that control the postfault deposits in the Morrison Formation. Similar 

sets may control postfault deposits in the Morrison 

Formation and Dakota Sandstone in the Gallup district. Other fractures of similar and younger ages 

largely control the oxidized parts of deposits in rocks 

of pre-Tertiary age; fractures of mid-Tertiary age, 

and younger, control most of the deposits in rocks of 

post-Cretaceous age.

Control on the deposits in limestone are primarily 

structural and partly sedimentary and possibly chemical but of unknown nature. They are controlled principally by intraformational folds and partly by 

broader folds of probable Late Jurassic age. Fractures show little apparent effect on them, except for 

the oxidized minerals. These folds are best formed 

in the Ambrosia Lake and Laguna districts but also 

occur on a smaller scale in the Chuska district, in San 

Juan County, and in Rio Arriba County. It is noteworthy that the principal deposits are associated with 

the best formed structural features, which occur along 

the south margin of the old Jurassic basin. These 

features may be directly controlled by the thickness of

the limestone in the Todilto Limestone (fig. 5). Smaller 

deposits are associated with the smaller scale features.

The precipitating agent of the uranium in limestone is not known. It was not fluorapatite but possibly 

was organic carbon or may have been S or HS 

ions, as implied by Bell (1963, p. 17).

Controls on the deposits in shale and coal are principally carbonaceous material and, to a lesser extent, 

sedimentary and tectonic structural features. A few 

unimportant occurrences in noncarbonaceous shale are 

apparently controlled by the clay minerals which 

served as precipitants of the uranium. Where deposits 

are least carbonaceous, the sedimentary and structural 

controls are more dominant ,and show the same controls and relations to the host rocks as the deposits 

in sandstone. Where they are highly carbonaceous, 

however, the sedimentary and age relations and some 

structural re^itions are obscure. In som0!, as in the 

Cretaceous rocks of La Ventana Mesa, the deposits 

are controlled partly by folds and joints. Most of the 

deposits, however, occur at the surface and, because of 

their tendency to remain in a reduced state, their age relationship to sedimentary and tectonic structural features is difficult to determine. Probably many of them, 

especially those in rocks of post-Cretaceous age, are late 

Tertiary to Quaternary in age.

Controls on most vein deposits in metamorphic 

and igneous rocks are direct and fairly obvious, but 

in sedimentary rocks they are both direct and indirect. 

In metamorphic rocks the deposits are controlled by 

fissures and fractures of Precambrian age. In igneous 

rocks they likewise are controlled by similar structural 

features and breccia zones. At the La Bajada such 

features are probably Oligocene in age; at most others 

they are Miocene (?) or later in age. Most of these 

deposits are oxidized and probably are surficial accumulations of Pleistocene or Recent age. In sedimentary 

rocks the controls are mostly tectonic features but are 

partly sedimentary and locally are chemical features. 

The oldest deposits are in sandstone pipes in the 

Morrison Formation, which are controlled principally 

by the bounding faults, of Late Jurassic age, but 

partly by sedimentary structural features next to the 

faults and partly by finely disseminated carbonaceous 

material, similar to the peneconcordant deposits in 

sandstone. Indirectly, these deposits also probably are 

controlled by the old Jurassic basin and subordinate 

folds of the same age that formed on the basin margin. Other vein deposits in sedimentary recks are controlled by faults and fractures and partly by sedimentary structural features. They occur in and along
DISTRIBUTION OF ELEMENTS IN THE ORES

the Rio Grande trough, so are controlled by the trough 

as well as by the subsidiary faults with which they 

are associated. These structural features are Miocene(?) to Recent in age. The vein deposits also are 

partly controlled by sedimentary structural features 

near the fractures and locally by pockets or concentrations of coalified plant debris.

ORIGIN

Origin of the uranium deposits, which in general 

is controversial, is of interest because it has a direct 

bearing on the estimation of the resources, particularly 

for the peneconcordant deposits because of their great 

potential. Vein deposits have little potential and their 

origin is better understood, so are treated briefly.

Because stratigraphic relations of the peneconcordant deposits demonstrate that the deposits were 

emplaced after the host rocks, the source of the uranium was either from some other part of the host 

rocks or was external to them. The original source is 

of interest, but the direction of transport is of greater 

concern because of its bearing on the final disposition 

and distribution of the deposits. Attention will be 

focused on the deposits in the Upper Jurassic rocks 

along the south margin of the San Juan Basin, which 

are most important and about which the geology is 

better understood than elsewhere.

The geologic setting during Late Jurassic time was 

a broad southern highland area that shed clastic 

debris into a broad shallow basin to the north. During deposition the highland was uplifted and the basin 

differentially sank. This sinking permitted an accumulation of Jurassic sediments that now total about 1,000 

feet in thickness. Near the close of Jurassic time the 

highland area as well as the remainder of the entire 

region was beveled prior to encroachment by Cretaceous seas from the southeast and northeast.

Some time following deposition of the sediments, 

the uranium deposits were emplaced. Before the 

source and direction of transport can be discussed, 

two basic assumptions must be made. First, the transporting solutions were dilute and, second, the fact 

that the solutions were dilute would require the passage of large volumes of such solutions past the points 

or areas of precipitation. The first assumption is generally accepted, and the second assumption is a necessary corollary for the precipitation of enough uranium to build the large deposits that occur in the Jurassic rocks.

If the source of the uranium was from within the 

host rocks, the direction of transport had to be 

largely lateral, or roughly parallel to the bedding. 

If it was external, the transport could have been

by ascending, descending, or laterally migrating solutions, or some combination of such movements. Of 

these various possibilities most probably the solutions 

moved laterally and downdip, as indicated by the 

hydrologic conditions that can be reconstructed from 

the structural setting, age of emplacement, and the 

general stratigraphic relations of the deposits.

The deposits occur along or near the south margin 

of the basin of deposition. This was the principal ar^a 

of recharge during sedimentation and most likely was 

the locale of greatest flow of water per unit area within the basin sediments. Basinward from the recharge 

area the waters would eventually ascend toward the 

surface but only after a loss in velocity and a decreased rate of flow per unit area. Loss in velocity 

would result from friction, which would cause the 

waters to spread and flow through a greater crorssectional area. The friction must have been intensified 

by the increasing fineness and decreasing permeability 

of the sediments away from the basin margins.

No structural or hydrologic evidence suggests that 

the solutions could have moved from the basin toward 

the margins, or that the principal direction of movement was downward or upward. Downward movement 

of any appreciable volume would have required a 

breached structure prior to Tertiary time, of which 

there is no evidence. Upward movement would have 

required hydraulic pressures at depth great enough to 

overcome the hydrostatic head and the friction of 

transmission to cause and maintain flow. Possibly 

such flow could have been caused by magmatic pressure beneath the deposits, but this condition would 

have required a fracture system. No evidence indicates such a system older than Laramide age, which 

would have been predated by the primary uranium 

deposits. Furthermore, no evidence indicates igneons 

intrusions between Precambrian and mid-Tertiary tine 

along or even near the south margin of the Jurassic 

basin. Such intrusion would be expected if magmatic pressures great enough to have caused flow had 

existed.

One possible alternative process that might have 

induced some upward flow was dewatering of the sediments by compaction. Such a process, however, would 

have generated only a small volume of flow hardly 

the amount necessary to satisfy the needs.

Conclusions are, therefore, that the uranium-bearing 

solutions flowed basinward from a recharge area along 

the south margin of the sedimentary basin. Und^r 

these circumstances the uranium could have originally 

been derived from the highland bedrock or leached 

from the host rocks, possibly in large part from the
144 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

contained volcanic debris. Characteristics of the oresample groups and the distribution of trace elements 

in the Todilto Limestone support this conclusion. The 

general uniformity in the contents of the elemental 

assemblages in the ore sample groups and the zonal 

arrangement of the elements in and around the deposits in the Todilto Limestone are not only compatible with the derivation of the deposits from the 

host rocks or highland bedrock, but also some elemental concentrations in the ore, such as fluorine, for 

example, are more readily explained by a rearrangement within the host rock, rather than by a derivation 

from magmatic fluids or some other external source.

If these premises are correct, the general hydrologic conditions during sedimentation and the relations of the uranium deposits to the Jurassic structures and stratigraphy deserve further consideration 

for they reflect the chronology of emplacement.

Under the general hydrologic conditions that would 

be expected during sedimentation in a basin, water 

entering the recharge area first would fall stratigraphic ally as it entered the basin, then would pass 

more or less parallel to the bedding and, finally, would 

rise stratigraphically as it approached the central 

part of the basin. The rate of flow per unit area would 

be progressively slower with distance from the recharge area, so the maximum flow per unit area would 

be maintained within the upper part of the sedimentary column throughout the depositional history of 

the basin. Because of continued sedimentation, the 

maximum rate of flow per unit area would progressively rise from older to younger stratigraphic zones; 

for example, the older zone of the Todilto Limestone 

to the younger zone of the Morrison Formation.

As indicated previously under the section on ages 

of emplacement (p. 139), the structural relations of the 

deposits in the Todilto Limestone in the Laguna district indicate that they were emplaced during Late 

Jurassic folding. It was also noted that the deposits 

in the Todilto Limestone and in the Morrison Formation were both closely associated with flowage structures and that there was some reason to believe the 

time of emplacement closely followed the flowage of 

the sediments in the intraformational folds and in the 

sandstone pipes. Admittedly, the reasoning is rather 

tenuous, but coupled with that on the hydrology involved during sedimentation and on the probable 

direction of transport, indications are not only highly probable that the deposits were emplaced during 

Late Jurassic sedimentation but that the deposits in 

the Todilto Limestone were emplaced somewhat earlier than the ones in the Morrison Formation.

Conclusions are, therefore, that the deposits were 

emplaced by solutions that moved northward and 

mainly laterally through the host rocks in Late Jurassic time. The deposits in the Todilto Limestone 

were emplaced first, then the deposits in the Morrison 

Formation. Most probably the uranium was derived 

from the highland bedrock or from volcanic debris 

within the host rocks, or from both.

Origin of the deposits in other parts of the Jurassic 

basin probably was similar to that of th?< ones along 

the south margin. The deposits in the Jurassic basin 

also apparently predate the Laramide structures, and, 

except for possibly being emplaced farther within the 

basin, had a similar geologic history. Th<3 ones in the 

Chuska and Shiprock districts, for example, are nearest the old basin margin in northwestern Arizona and 

were probably derived from that source. If so, the 

fact that the deposits rise stratigraphically from the 

Salt Wash Member in the Lukaclmkai district in 

Arizona to the Recapture Member in the Chuska district in New Mexico is perhaps noteworthy. This 

would be the expected general relation along the line 

of flow within the basin where the urariferous solutions would be rising.

Origin of the deposits in the other sedimentary 

basins probably was similar, but these deposits most 

likely were emplaced at different times from late 

Paleozoic to Quaternary. As indicated previously, the 

more important deposits in the Pennsylvanian, Permian, and Triassic rocks and the principal ones in 

the Dakota Sandstone of the Cretaceous rocks nearly 

all occur near the margins of the depositional basins. 

The similar structural relations of thes?, deposits to 

the ones in the Jurassic basin of deposition strongly 

suggest that the deposits in each basm also were 

emplaced shortly after the respective host rocks were 

deposited and by solutions that flowed basinward 

from the adjoining highlands. Credence is added to 

this general relationship by the structural relations 

of the Diamond 2 deposits in the Dakota Sandstone of 

the Gallup district.

The Diamond 2 deposits apparently were emplaced 

after flowage structures were formed and may have 

been controlled partly by Laramide folds, but they predate fractures of probable Laramide age. These structural limitations more or less fix the age of emplacement in early Laramide time and possibly early in the 

Cretaceous shortly after deposition of the sediments.

Of all the principal deposits in the sedimentary 

basins, only those in the Shinarump Member of the 

Chinle Formation are situated within the central part 

of the basin of deposition. (The deposits are largely 

within southeastern Utah and northeastern Arizona.)
URANIUM RESOURCES 145

This relationship probably was caused partly by the 

low permeability of the Moenkopi Formation which 

underlies the Chinle Formation and, in many places, 

directly underlies the Shinarump Member and partly 

by the uplift and northward tilting of the basin 

following Moenkopi deposition. Uplift and tilting 

resulted in dewatering and compaction of the Moenkopi. These factors added to its impermeability and 

formed the broad planelike or pedimentlike suface on 

which the Shinarump was subsequently deposited 

(Stokes, 1950). In this setting, water moving from 

the recharge area during and following Shinarump 

deposition was largely confined within the Shinarump Member and moved into the central part of the 

basin before being evaporated at the surface.

Origin of the deposits in the Tertiary basins is 

more speculative. Many of the deposits are certainly 

surficial and Recent. Possibly the deposits were 

formed in these basins during the early history of the 

basins and were similar in emplacement to the ones in 

the older basins, but such deposits perhaps were not 

preserved, as all of the basins were breached at least 

in part and were subjected to leaching by ground 

waters, especially after mid-Tertiary time. The fact 

that the older deposits are preserved, however, casts 

doubt on similar deposits of younger age having been 

removed. Conclusions are that deposits probably 

formed in the Tertiary basins that are similar to the 

deposits in the older basins, but they are hidden. The 

known deposits are interpreted to be superficial accumulations and Recent in age.

The vein deposits in sandstone pipes in the Morrison Formation in the Laguna and Ambrosia Lake 

districts are the same age and probably were derived 

from the same solutions as were the peneconcordant 

deposits in the same rocks. As indicated previously, the 

pipes probably are intraformational and of Late Jurassic age. If they served as conduits for mineralizing 

solutions they could have connected beds only within 

the Jurassic sediments. Vein deposits along faults in 

the sedimentary rocks along the Rio Grande trough 

probably are similar in origin to the peneconcordant 

deposits in the same rocks. This is indicated by their 

superficial character, oxidized minerals, and general 

lack of alteration that would be expected if they were 

associated with more deep seated solutions. A possible exception is the Charley 2 deposit. Vein deposits 

in metamorphic rocks were derived from magmatic 

solutions in Precambrian time. The La Bajada deposit 

was derived from magmatic solutions in Oligocene 

time. A few other scattered vein deposits in igneous 

rocks along the Rio Grande trough also probably

were derived from magmatic solutions during late 

Tertiary and Quaternary time.

URANIUM RESOURCES

Uranium resources are the materials in the grourd 

that are minable now plus materials that are likely to 

become minable in the future. The resources include 

reserves and ore. Reserves are materials that may or 

may not be completely explored but which may be 

estimated quantitatively and are considered to be economically exploitable at the time of estimation. O~e 

is material that can be mined at a profit. The tern 

"ore reserves," or "mine reserves," applies to deposits 

currently being mined, or to deposits known to be of 

such size and grade that they may be mined profitably.

This resource estimate is based largely on the habits, trends, and geology of the known deposits, on 

recent ore-reserve estimates, on records of past production, and partly on origin of the deposits. Because 

of the somewhat erratic occurrence of uranium depo«- 

its and because of the diverse geologic controls of 

those deposits, the estimate cannot be exact but is r,n 

expression of a general order of magnitude.

As of January 1, 1966, the U.S. Atomic Energy 

Commission estimated the uranium mine reserves in 

northwestern New Mexico to be 29.7 million tons of 

ore averaging 0.23 percent U3O8 and containing abo\it 

70,000 tons of U3O8 .3 During 1965 about 2 million 

tons of ore was mined which, totaled with the previous 

output, amounts to about 25 million tons that has been 

extracted through 1965. At the 1965 rate of extraction, 

the mine reserves would sustain a yield for 15 years 

or until about the end of 1980. About 99 percent of 

these reserves are in Morrison Formation; the remaining 1 percent is mostly in the Todilto Limestone and 

Dakota Sandstone. About 60 percent of the reserves 

are in the Ambrosia Lake district; most of the 

remainder is in the Laguna district.

An appreciable tonnage of material of submarginal 

grade occurs on the periphery of the known ore deposits, particularly in the deeper deposits in the Mo^- 

rison Formation in the Ambrosia Lake district. This 

material has not been thoroughly sampled and i*s 

tonnage has not been calculated, but it probaWy 

amounts to several million tons of material averaging 

about 0.1 percent U3O8 .

In contained uranium this submarginal material 

greatly exceeds all other known submarginal uranium 

resources. The only other submarginal material cf 

much importance in northwestern New Mexico is mostly

s Robert K. Pitman (written commun., Apr. 4, 1966). Publication 

by permission of the U.S. Atomic Energy Commission.
146 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

in impure coal at the top of the Menefee Formation 

in the La Ventaiia Mesa area. The coal is estimated to 

contain 132,000 tons of material 1 foot or more thick 

and containing at least 0.1 percent uranium and about 

400,000 tons of material that ranges from 0.01 to 0.1 

percent uranium (Bachman and others, 1959, p. 307).

As of January 1966, the total uranium resources 

probably amounted to several times the total past 

mine output plus mine reserves. These resources may 

amount to as much as 200 million tons of material 

averaging about 0.25 per cent U3O8 . Most of these 

resources are in peneconcordant deposits several hundred to several thousand feet below the surface. They 

are mostly in sandstone masses that occupy structural 

depressions of Late Jurassic age. These structures 

probably occur mostly in the periphery of the San 

Juan Basin and largely within the southern San Juan 

Basin mineral belt, now generally referred to as the 

Grants mineral belt. More than 90 percent of the 

resources are probably in the Morrison Formation. 

Most of the rest probably are in the Todilto Limestone and Dakota Sandstone, but a small percentage 

may occur in other formations. In addition, a small 

percentage of the resources is in vein deposits in rocks 

of diverse lithology and age.

A general breakdown of these resources is made by 

formational units, from oldest to youngest, under 

which the general size and abundance of the known 

deposits and the resource potential and disposition 

are discussed; mine reserves are listed where figures 

are available from the Atomic Energy Commission. 

These data are summarized in table 16.

PRECAMBRIAN ROCKS

Ortega Quartzite of Just (1937} and others rocks. 

A few scattered occurrences of uranium minerals have 

been found in association with fluorite veins and 

in pegmatite bodies in the Ortega Quartzite of Just 

(1937). None of these occurrences are of commercial 

importance, as far as uranium is concerned, and the 

outlook is poor for the Ortega or other rocks of Preeambrian age to contain any resources of much value. 

This estimation is based on the sparseness of the known 

occurrences and their lean values and on the poor 

general outlook for pegmatite bodies to contain substantial or recoverable quantities of uranium (Page, 

1950, p. 33).

CAMBRIAN(?) ROCKS

Unnamed conglomeratic sandstone and xhale. No 

uranium deposits are known in the Cambrian (?) 

rocks, which are deeply buried under the northwestern 

part of the San Juan Basin and are unexplored except 

by test wells for oil. These rocks might possibly contain some uranium resources, but any uranium contained in them would not be economically recoverable 

in the foreseeable future.

DEVONIAN ROCKS

Elbert Formation. Shale, glauconitic sandstone, and 

some sandy carbonate rocks, which are probably extensions of the Elbert Formation, are deeply buried under 

the northern part of the San Juan Basin. They also are 

largely unexplored and contain no known uranium deposits. It is unlikely they contain any uranium resources 

as they are near-shore marine, or littoral, in origin, 

and are rocks that rarely contain any appreciable 

amount of uranium, thus their resource potential is

poor.

MISSISSIPPIAN ROCKS

Leadmlle Limestone, Caloso Formation of Kelley and 

Silver (1952], Kelly Limestone, and Arroyo Penasco Formation. Mississippian rocks also are barren of 

known uranium deposits and their resource potential 

also is poor. Limestone in general is a poor host rock for 

uranium, except where deformed or fractured (Hilpert, 

1961) or, in a few occurrences, where it is in solution 

cavities in karst terrains (Bell, 1963). Possibly a few 

small deposits might be found in these rocks where they 

are faulted, particularly along the Rio Grande trough.

PENNSYLVANIAN ROCKS

Molas, Hernwsa, and lower part of Rico Formations. These rocks, also, do not contain known uranium 

deposits and are buried under the nortl Q,rn part of 

the San Juan Basin. They are marine and marginal 

marine-continental fine-grained elastics, carbonates, 

and some evaporites, all of which are poor hosts for 

uranium. The uranium potential for these rocks is 

poor and they likely contain no uranium resources.

Sandia Formation. The Sandia Formation, which is 

a near-shore marine deposit of fine-grained elastics and 

earthy limestone, contains no known uranium deposits. 

Its resource potential is poor for the same reasons given 

for the Molas, Hermosa, and lower part of the Rico 

Formations.

Madera Limestone. The Madera Limestone contains 

two small deposits along faults on the eart side of the 

Rio Grande trough and one occurrence is in arkosic 

sedimentary rocks in the San Pedro Mountains. The 

resource potential of the Madera is fair to poor. A few 

additional small deposits might occur when the Madera 

is faulted along the Rio Grande trough. Elsewhere it is 

unfavorable, except along its north margin where the 

marine beds grade northward into unnamed continental 

f acies along the old northern highland area. Here, wnere 

arkosic beds dip southward under the Chama Basin, the
URANIUM RESOURCES 147

potential for the occurrence of some small or possibly 

medium-sized deposits in the thicker coarser grained 

sandstones may be considered to be fair. Except along 

the north margin of the Chama Basin, the favorable 

beds are several thousand feet below the surface; they 

become less favorable southward where they grade into 

marine beds.

PERMIAN ROCKS

Bursum Formation. The Bursum Formation in 

northwestern New Mexico is barren of known uranium 

deposits and probably contains few, if any, uranium 

resources. Some deposits may possibly occur in arkosic 

sandstone lenses in Torrance County, which is just west 

of the Pedernal highland area, the source of the arkosic 

material.

Abo Formation. The Abo Formation contains a few 

small deposits in arkosic carbonaceous sandstone beds. 

The resource potential of the formation is fair and it 

probably contains numerous small deposits and possibly 

some medium-sized deposits back from the outcrop. 

The best potential is in the relatively thick coarsegrained arkosic sandstone lenses near the ancestral highland areas in western Torrance and eastern Socorro and 

Valencia Counties.

Cutler Formation Several small uranium deposits 

occur in the Cutler Formation near the base in arkosic 

carbonaceous sandstone lenses. The resource potential is 

fair to possibly good in similar sandstone lenses where 

they are about 30 feet or more thick. Most of the resources probably occur from the San Pedro Mountains 

area northward to the north margin of the Chama Basin, 

which is marginal to the ancestral highland. Elsewhere 

the Cutler is finer grained and more thin bedded or is 

largely aeolian in origin and unfavorable.

Yeso Formation and Glorieta, /Sandstone. The Yeso 

Formation and the Glorieta Sandstone are barren of 

known uranium deposits and probably contain no uranium resources. They consist of marine fine-grained sandstone, siltstone, limestone, and some evaporites, all generally considered unfavorable for uranium deposits.

San Andres Limestone. A few small uranium deposits occur in the San Andres Limestone where it is 

faulted. The San Andres Limetone probably contains a 

few additional small deposits where it is faulted, especially along the Rio Grande trough, but the resource 

potential generally is poor. It is a marine deposit of 

limestone, shale, thin-bedded sandstone, and some evaporites, rocks that are considered unfavorable for 

uranium.

Bernal Formation. The Bernal Formation contains 

no known uranium deposits and probably has poor resource potential, for the same reasons as the San Andres 

Limestone.

TRIASSIC ROCKS

Moenkopi(f) Formation. TheMoenkopi(?) Formation contains no known uranium deposits in New Mexico 

and has a poor resource potential. It is mostly siltstone, 

which generally is unfavorable for uranium deposits.

Chinle Formation. The Chinle Formation in New 

Mexico contains only a few scattered small deposits of 

uranium. These mostly are in fairly thick arkosic carbonaceous sandstone units, namely the Shinarump Member, Poleo Sandstone Lentil, and Agua Zarca Sandstone 

Member. The resource potential for the Chinle is frir. 

The formation probably contains numerous small deposits and possibly back from the outcrop some mediumsized deposits. These resources probably are mostly in 

the Shinarump Member, but some are expected in the 

Agua Zarca and possibly some in the Poleo Sandstone 

Lentil and Sonsela Sandstone Bed. The potential of 

these units is rather speculative because of their limited 

exposures and questions regarding their source areas. 

The potential for the Shinarump is considered the b^,st 

for the members because of its rather uniform regional 

extent and the pediment conditions that probably influenced the widespread distribution of the uranium deposits away from, or remote from, the highland source 

area. The limited exposures of the Shinarump in New 

Mexico probably are not representative of the unit 

under cover in the western part of the area. The nor*iiern part of the Agua Zarca is obviously near the 

highland source area and is the most favorable of the 

other sandstone units. The Poleo Sandstone Lentil and 

the Sonsela Sandstone Bed, where they are preserved, 

may lie farther from the highland sources and are 

therefore, possibly less favorable.

Dockum Formation. One uranium occurrence is 

known in the Dockum Formation, which is lithologically similar to the Chinle Formation. The resource 

potential of the Dockum is poor to fair. The formation 

locally contains arkosic sandstone lenses as much as 50 

feet thick, and these are similar to the arkosic sandstone 

units of the Chinle Formation, which is a partial stratigraphic equivalent. In the periphery of the highland 

source area the thicker lenses might contain sotie 

uranium deposits of small to medium size.

Wingate Sandstone. The Wingate Sandstone contains no known uranium deposits in New Mexico and 

probably contains no uranium resources. It is largely 

an eolian deposit and generally considered unfavorable 

for uranium deposits.
148 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

TABLE 16. A listing of the relative size and abundance of known uranium deposits, relative magnitude of mine or submarginal reserves, 

and potential for undiscovered resources, in the formational units of northwestern New Mexico

[Uranium deposits: Abundance and size: small, <1,000 tons; medium, 1,000-100,000 tons; large, >100,000 to 1 million tons; very large, more than 1 million tons]

Era

Cenozoic

Mesozoic

System or Period

Quaternary and Tertiary

Rio Grande

trough and

vicinity

Tertiary

Datil volcanic

field area

San Juan Basin

Cretaceous

Jurassic

Formational unit

Intrusive rocks of varied

composition and form.

Santa Fe Group

Popotosa Formation

Espinaso Volcanics and

Cieneguilla Limburgite

Galisteo Formation

Older volcanic rocks

of Jemez Mountains

Datil Formation

Baca Formation

Chuska Sandstone

San Jose Formation

Nacimiento Formation

Animas Formation

Ojo Alamo Sandstone

McDermott Formation

Kirtland Shale

Fruitland Formation

Pictured Cliffs Sandstone

Lewis Shale

Mesaverde Group, undivided

Cliff House Sandstone

Menefee Formation

Point Lookout Sandstone

Crevasse Canyon Formation

Gallup Sandstone

Mancos Shale

Dakota Sandstone

Morrison Formation

Brushy Basin Member

Westwater Canyon

Member

Recapture Member

Salt Wash Member

Bluff Sandstone

Summerville Formation

Todilto Limestone

Entrada Sandstone

Uranium deposits

Few; small

Many; small

Few; small to medium

Few; small

Few; small to medium

Few; small

Few; small

Many; small to medium

None

Few; small

Few; small

None

Few; small

None

None

Few; small

None

None

Few; small

Few; small

Few; small to large

Few; small

Few; small

Few; small

None

Many; small to medium

Many; small to very

large

Many; small to very

large

Many; small to very

large

Many; small to medium

Many; small to medium

None

Many; small

Many; small to large

Many; small

Mine or submarginal reserves

None

Small

Small

Small

Small

None

None

Small

None

None

None

None

None

None

None

Small

None

None

None

None

Moderate

Small

Small

Small

None

Moderate

Moderate to

very large

Very large

Very large

Moderate

Moderate

None

Small

Large

Small

Potential

Foor.

Foor to good.

Foor to good.

Fair.

Foor to good.

Foor.

Foor.

Fair.

Foor.

Foor to fair.

Foor to fair.

Foor to fair.

Foor to fair.

Jfoor to fair.

Foor.

Foor.

Foor.

Foor.

Foor.

Foor.

Fair.

Foor.

Foor.

Foor.

Foor.

Good.

Good to excellent.

Fair to excellent.

Fair to excellent.

Good.

Good.

Foor.

Poor to fair.

Good.

Poor to fair.
URANIUM RESOURCES 149

TABLE 16. A listing of the relative size and abundance of known uranium deposits, relative magnitude of mine or submarginal reserves 

and potential for undiscovered resources, in the formational units of northwestern New Mexico Continued

Era

Mesozoic

Paleozoic

Precambrian

System or Period

Triassic

Eastern side of 

the San 

Juan Basin

Western and 

southern sides 

of the San 

Juan Basin

Permian

Pennsylvanian

Mississippian

Devonian

Cambrian (?)

Precambrian

Formational unit

Wingate Sandstone 

Dockum Formation

Chinle Formation 

Petrified Forest Member, including Poleo 

Sandstone lentil

Agua Zarca Sandstone 

Member

Chinle Formation 

Petrified Forest Member, 

including Sonsela 

Sandstone Bed 

Shinarump Member 

Moenkopi Formation

Bernal Formation 

San Andres Limestone 

Glorieta Sandstone 

Yeso Formation 

Cutler Formation

Abo Formation 

Bursum Formation

Madera Limestone and 

unnamed arkosic 

sediments 

Sandia Formation 

Molas, Hermosa, and 

Rico Formations

Arroyo Penasco 

Formation 

Kelly Limestone 

Caloso Formation 

Leadville Limestone

Elbert Formation

Unnamed conglomeratic 

sandstone and shale

Ortega Quartzite and 

other rocks

Uranium deposits

None 

Few; small

Few; small 

Few; small

Few; small

Few; small 

None

Few; small 

None

None 

Few; small 

None 

None 

Few; small

Few; small 

None

Few; small

None 

None

None

None 

None 

None

None

None

Few; small

Mine or submarginal reserves

None 

Small

None 

None

None

Small 

None

Small 

None

None 

Small 

None 

None 

Small

Small 

None

Small

None 

None

None

None 

None 

None

None

None

None

Potential

Poor. 

Poor to fair.

Poor to good. 

Poor to fair.

Fair to good.

Poor to good. 

Poor to fair.

Fair to good. 

Poor.

Poor. 

Fair to poor. 

Poor. 

Poor. 

Fair to possibly good. 

Fair. 

Poor.

Fair to poor.

Poor. 

Poor.

Poor.

Poor. 

Poor. 

Poor.

Poor.

Poor.

Poor.
150 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

JURASSIC ROCKS

Sandstone. The Entrada Sandstone contains numerous small deposits or parts of deposits at 

the top. A few have been mined, but the reserves are 

small. The uranium in the Entrada is associated with 

deposits in the overlying Todilto Limestone. The Entrada is an eolian sandstone and partly a marine siltstone, both rocks generally being unfavorable for 

uranium. Except for parts of the Entrada that directly 

underlie deposits in the Todilto Limestone, the resource 

potential is poor. Immediately under favorable Todilto 

structural features, however, the Entrada has a fair 

potential for containing parts of some small to mediumsized deposits.

Todilto Limestone. The Todilto Limestone contains 

many deposits that mostly range from small to medium 

size. Mine reserves total about 200,000 tons of material 

that averages about 0.30 percent TJ3O8 and is in ore 

bodies that average a few feet in thickness. These 

reserves are almost entirely in the Ambrosia Lake district. Total resources in the Todilto are probably many 

times the total of past mine production and mine 

reserves, perhaps 5 to 10 times as much. Although the 

potential resource outlook for the Todilto is good, the 

deposits are mostly deeply buried and will be costly to 

find and exploit. These resources most likely are in the 

southern San Juan Basin mineral belt in the Ambrosia 

Lake and Laguna districts where the limestone unit is 

15 or more feet thick. This is nearest the old highland 

area where tectonic activity was most intensive during 

deposition and caused the intraformational folds which 

control the deposits. The resources probably occur in 

deposits of about the same size and grade 'as those that 

have been found, but they mostly will be found below the 

surface and will be progressively deeper back from the 

outcrop, the deepest being several thousand feet below 

the surface. A small part of the Todilto resources likely 

occurs in some small deposits in the Chuska district and 

in and near the southern part of the Chama Basin.

Sunimerville Formation. The Summerville Formation contains numerous small deposits or parts of 

deposits at the base. A few have been mined, but the 

reserves are small. Deposits in the Summerville are 

associated with the deposits in the underlying Todilto 

Limestone, similar to the ones in the Entrada Formation. The resource potential of the Summerville is 

likewise poor. The host rocks are mostly marine thinbedded sandstone and siltstone, generally considered 

unfavorable for uranium deposits. Just overlying the 

favorable Todilto Limestone structures, the base of the 

Summerville has a fair potential for containing parts 

of some small to medium-sized deposits. These resources

will occur in the same areas as the Todil'io Limestone 

resources.

Blwff Sandstone. The Bluff Sandstone is barren of 

known uranium deposits and probably contains no 

uranium resources of any consequence. It is an eolian 

deposit and generally considered unfavorable for 

uranium.

Mom son Formation. Deposits ranging in size from 

small to very large occur in the Morrison Formation. 

It has been the most prolific producer of uranium and 

has the greatest potential for containing substantial 

resources. The mine reserves total more than 29 million 

tons of material which has an average content of about 

0.23 percent U3O8 and which occurs in ore bodies that 

range in thickness from a few to several tens of feet. 

About 60 percent of these reserves are in the Ambrosia 

Lake district; most of the remainder is in the Laguna 

district.

The resource outlook for the Morrison is fair to 

excellent in the various members and localities. Overall it probably contains resources that are several times 

as great as the total of the past product'on and presently known mine reserves. At least 90 percent of this 

material is expected in the southern San Juan Basin 

mineral belt in the Ambrosia Lake, Gallop, and Laguna 

districts. The remainder is expected to be mostly in the 

eastern parts of the Chuska and ShiprocJ- districts.

Most of the resources are expected to be in relatively thick sandstone masses that occupy structural 

depressions of Late Jurassic age in the following districts: (1) Laguna district, mostly in the Brushy 

Basin Member in the Jackpile sandstone of economic 

usage; (2) Ambrosia Lake and Gallup districts, mostly 

in the Westwater Canyon Member and partly in the 

Brushy Basin Member; (3) Chuska distinct, mostly in 

the Recapture Member; and (4) Shiprock district, 

mostly in the Salt Wash Member. A relatively small 

amount of the total resources is expected in numerous 

small deposits and perhaps a few of medium size in 

other areas in the Westwater Canyon Member and in 

sandstone lenses in the Brushy Basin Member where 

they exceed about 25 feet in thickness.

Most of the resources in the Morrison probably 

occur in deposits of about the same size and grade as 

those that have been mined and developed in the 

various districts and areas but at greater depths. Most 

resources in the principal mining districts range in 

depth from a few hundred to several thousand feet 

below the surface.

CRETACEOUS ROCKS

Dakota Sandstone. Numerous small and some medium-size deposits occur in the Dakota Sandstone,
URANIUM RESOURCES

several of which have been mined. Few mine reserves 

were known at the end of 1965. The uranium resources in 

the Dakota are expected to be roughly 10 times the total 

of those that have been discovered and mined. Most of 

these resources occur back from the outcrop in the Gullup and Ambrosia Lake districts, principally in channeltype sandstone at the base of the formation. Some 

occur in low-grade coal and in carbonaceous shale in 

these districts and elsewhere. Most of the resources 

probably occur within the western part of the southern 

San Juan Basin mineral belt; this part is nearest the 

highland area that contributed the sediments, and it 

contains the largest and thickest channel-type sandstones. These resources are a few hundred to several 

thousand feet below the surface.

Mancos Shale, Gallup Sandstone, Crevasse Canyon 

Formation, Point Lookout Sandstone, Menefee Formation, Cliff Home Sandstone, Lewis Shale, Pictured Cliffs 

Sandstone, Fmitland, Formation, Kirtland Shale, Ojo 

Alamo Sandstone, and An/mas Formation (Upper Cretaceous and Pal eocene], Scattered uranium deposits 

occur in some of these formations but. are mostly surficial 

occurrences. A few are small and several are medium in 

size. Except for the submarginal reserves at the base of 

the La Ventana Tongue of the Cliff House Sandstone, 

the known resources in these rocks are small.

The resource potential for most of these rocks is 

poor. They are nearly all marine or near-shore marine 

clastic sediments, except for the Ojo Alamo and Animas (in part of Paleocene age) Formations, and generally are unfavorable for uranium. Most of the known 

deposits are accumulations at the top or base of sandstone units, are surficial, and are associated with 

lenses or beds of carbonaceous debris. Locally, however, the potential for some small and medium-sized 

deposits in low-grade coals and highly carbonaceous 

materials is fair. These deposits most likely occur near 

the surface in structural depressions or where the beds 

may be faulted.

The Ojo Alamo and Animas Formations are continental clastic sedimentary rocks, including arkosic 

sandstone units, that are several thousand feet thick, 

but they are barren of known uranium deposits except 

for some minor occurrences in the Ojo Alamo. The 

resource potential for these formations is uncertain but 

probably ranges from poor to fair. The general lack 

of any deposits of much substance in the widely 

exposed surface indicates a poor outlook, but the presence of fairly thick lenses of arkosic sandstone and 

some included woody debris is a favorable indication 

that uranium deposits of substantial size might occur 

in the subsurface.

TERTIARY ROCKS

Nacimiento and San, Jose Formations. Several 

small deposits similar to the ones in the Ojo Alarr*} 

have been noted in the Nacimiento and San Jo^e 

Formations. The resource potential is uncertain but 

is rated poor to fair, similar to that of the Ojo 

Alamo and Animas Formations. Because of its fine 

grain size, most of the Nacimiento is considered potentially poor. In its northern part, largely under the 

San Jose Formation, it is considered potentially fair 

because of its coarser grain size. The San Jose is composed of material that is coarser grained than that in 

the Nacimiento, and many of the units in it appear to 

be favorable hosts for uranium deposits. The potential of the formation is rated no better than fair, however, because of its widespread exposure and the 

sparseness in it of known deposits, all of which are 

small.

Chuska Sandstone. The potential for uranium deposits in the Chuska Sandstone is poor. This is indicated by the lack of uranium in rather widespread exposures, the paucity of carbonaceous material, and the 

possibility that much of the Chuska may be eolian in 

origin.

Baca Formation. The potential for the Baca Formation to contain substantial uranium resources is fair. 

These resources most likely occur in channel-type sanistone lenses along synclinal folds, similar to the occurrence of the known deposits.

Datil Formation. No deposits of much substance occur in the Datil Formation, and its resource potential is 

poor. The Datil consists mostly of volcanic debris and 

some fluvial clastic material, which are considered 

unfavorable for uranium deposits.

Galisteo Formation. The resource potential of the 

Galisteo Formation is considered to range from poor at 

the outcrop to good in the unexposed parts. The Galisteo 

is rather widely exposed, but only one uranium deposit is 

known. This deposit, however, is medium size, much of 

the formation is lithologically favorable for containing 

deposits, and most, of it is unexposed and unexplored. 

The unexplored parts 'are therefore considered potentially good for containing deposits that may range in 

size from small to large.

Popotosa. Formation. Several small occurrences and 

one medium-sized deposit, which is associated with a 

fault, occur in the Popotosa Formation. The resource 

potential of the Popotosa Formation is considered to 

range from poor to good for the same reasons that are 

given for the range for the Galisteo Formation.
152 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

Santa Fe Group (Miocene to Pleistocene?}. Several 

uranium deposits are known in rocks of the 

Santa Fe Group, but they generally are small and 

superficial. The resource outlook, however, is considered 

to range from poor at the outcrop to good in the subsurface, similar to the Galisteo and Popotosa Formations. The Santa Fe Group is widely exposed, but in 

most places only the upper few hundred feet of the 

sequence is represented; elsewhere the beds are covered 

by alluvium and surficial debris. Little, if any, exploration has been done for deposits in the unexposed 

beds. The great extent and thickness of these beds, and 

the f avorableness of many of them for containing uranium deposits, offer a good potential for deposits 

that may range in size from small to large.

Older volcanic rocks of Jeinez Mountains, Espinaso 

Volcanics of Stearns (191f3), CieneguiUa Lirnburgite of 

Steam* (1953) , and intrusive rocks of varied composition and form. One medium-sized vein deposit occurs 

in the Espinaso Volcanics of Stearns (1943) on the 

eastern side of the Los Cerrillos district; a few other 

scattered small deposits, which are mostly surficial 

accumulations, occur in various types of intrusive and 

extrusive igneous rocks, mainly along the Eio Grande 

trough. The uranium resources in these rocks are small 

and the outlook is poor for finding more than a few 

small, or possibly medium-sized, deposits in them. The 

best potential is in the Los Cerrillos and Ortiz mining 

districts, where some uraniferous vein deposits might 

be found in association with the base-metal deposits.

AREAS RECOMMENDED FOR EXPLORATION

The principal uranium resources in northwestern 

New Mexico are in peiieconcordant deposits, mostly in 

sandstone, partly in limestone, and to some extent in 

carbonaceous shale and coal. Most of these resources are 

along the margins of sedimentary basins, the most 

important of these areas being the southern and western parts of the San Juan Basin.

Of greatest importance is the southern part of the 

basin. On the basis of the frequency of distribution 

of the known deposits and their geologic relations, 

the deposits in this area are restricted to a zone or 

belt north of the outcrop of the Jurassic rocks which 

is at least 20 miles wide and which has been referred 

to as the southern San Juan Basin mineral belt (Hilpert and Moench, 1960). The northern limit of the 

belt is adjusted here to include the known areas of 

most intensive structural deformation during Late 

Jurassic time. This deformation is recognized as the 

prime control on the uranium deposits in the Morrison 

Formation and Todilto Limestone. As drawn, the 

northern limit of the belt extends from near the

northern pinchout of the Jackpile sandstone northwestward, parallel to the reconstructed boundary of the 

Jurassic basin of deposition, to the outcrop of the 

Morrison Formation on the western side of the San 

Juan Basin (fig. 20). Included in the belt are the 

Jackpile trough in the Laguna district (roughly 

marked by the Jackpile sandstone) and the main orebearing sandstone mass in the Ambrosk, Lake district 

(areas C and D, respectively, fig. 20). Other structurally deformed areas probably occur in the western 

part of the belt and along its north margin. Certainly 

such areas will not be expected to end abruptly where 

the north margin is indicated. The boundary is drawn 

to show approximately where the deformation became 

less intensive northward.

Included in the belt is the part of the limestone unit 

of the Todilto Limestone that is 15 feet or more 

thick. This part includes almost all the mine reserves, 

has yielded almost all the ore, and probably contains 

most of the uranium resources in the Todilto. Where 

the limestone unit of the Todilto was thickest, it probably received the most intensive deformation and 

thus is considered most favorable for deposits. The 

Todilto generally lies about 400-500 feet below the 

base of the Morrison Formation. Because of this general depth and the smaller deposits in it, the Todilto 

is not of immediate economic interest except where it 

is not deeply buried.

The mineral belt also contains the most favorable 

ground for uranium deposits in the Dakota Sandstone, although the Jurassic deformation probably had 

little, if any, influence on them. The best ground is 

in the western part of the belt, when? channel-type 

sandstone lenses are largest and thickest. This area is 

near the margin of the Dakota basin of deposition. 

Depths to the base of the Dakota will generally be 

about 500 feet nearer the surface than the base of the 

Morrison. Although the size of the deposits in the 

Dakota is about the same as the size of the ones in 

the Todilto, the deposits in the Dakota are more 

amenable to exploration and development, which can 

be coordinated with exploration for the deeper but 

generally larger deposits in the Morrifon Formation.

In the western part of the San Juan Basin substantial resources may also be found in the Shiprock 

district in the Salt Wash Member of the Morrison 

Formation and in the Chuska district in the Eecapture 

Member of the Morrison (fig. 20, areas A and B, respectively). Each of these areas defines the thicker 

part of the respective members where they apparently occupy eastward-trending structural depressions. 

Deposits in these rocks are expected to range from 

small to medium in size, similar to the ones at the
AREAS RECOMMENDED FOR EXPLORATION 153

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EXPLANATION

Approximate north limit of southern 

San Juan Basin mineral belt

Outcrop of Morrison Formation

South limit of Morrison Formation _ _ 

Protected between outcrops

Unconsolidated-Tertiary and

 Quaternary rocks in

Approximate south limit of RJO Qrande trough 

Salt Wash Member Pre-Tertbry rocks genera///

 >~/'-'-'K_'£ ': deeply buried 

' Ore-bearing sandstone lens or mass in 

| Morrison Formation

A, Salt Wash Member 

I B.Recapfure Member 

i C, Jackpile sandstone of economic usage of

L Brushy Basin Member 

D.Westwater Canyon and Brushy Basin Members 

i

South limit of Todilto Limestone

i 

1 Boundary of limestone unit of Todilto Limestone 

where it generally is 15 or more ft thick

50 MILES

 34°

E'IGUBE 20. Areas recommended for exploration.
154 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

outcrop. Eastward from the outcrop they will lie progressively deeper below the surface. In the Salt Wash 

the most favorable ground (area A) is largely on a 

structural terrace between the Mitten Rock and Hogback monoclines (fig. 3) where the member ranges 

from 0 to about 3,000 feet below the surface. In the 

Recapture the most favorable ground (area B) is 

largely in the Beautiful Mountain syncline, between 

the Defiance and Hogback monoclines (fig. 3) where 

the member ranges from 0 to about 3,000 feet below the 

surface. (See O'Sullivan and Beikman, 1963, sheet 2.)

In addition to the south and west sides of the San 

Juan Basin a few other areas offer some potential for 

finding deposits of economic interest.. These areas include Rio Arriba County, the western part of Torrance 

County, and eastern Catron County.

In Rio Arriba County some deposits may be found 

in arkosic sands in unnamed Pennsylvania!! rocks 

along the north margin of the Chama Basin and in 

arkosic sands in the Cutler Formation and Agua Zarca 

Member of the Chinle Formation along the south 

margin of the Chama Basin. In western Torrance 

County the Abo Formation might contain deposits in 

similar rocks. Some deposits might also be found in 

the Baca Formation in eastern Catron County, probably along synclinal structural features.

Deposits also may occur in the deeper parts of the 

Galisteo basin and within structurally closed segments 

of the Rio Grande trough, but many such deposits 

might be too deeply buried to be of immediate 

economic interest.

LITERATURE CITED

Akers, J. P., Cooley, M. E., and Repenning, C. A., 1958, Moenkopi and Chinle formations of Black Mesa and adjacents 

areas, in New Mexico Geol. Soc. Guidebook 9th Field 

Conf., Black Mesa Basin, northeastern Arizona, October 

1958, p. 88-94.

Alien, J. E., and Balk, Robert, 1954, Mineral resources of Fort 

Defiance and Tohatchi quadrangles, Arizona and New Mexico : New Mexico Bur. Mines and Mineral Resources Bull. 

36,192 p. 

Alien, V. T., 1930, Triassic bentonite of the Painted Desert: Am.

Jour Sci., 5th ser., v. 19, p. 282-288.

Altschuler, Z. S., Clarke, R. S., Jr., and Young, E. J., 1958, 

Geochemistry of uranium in apatite and phosphorite: U.S. 

Geol. Survey Prof. Paper 314-D, p. 45-90.

Anderson, R. Y., and Kirkland, D. W., 1960, Origin, varves, and 

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158 URANIUM RESOURCES OF NORTHWESTERN NEW MEXICO

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INDEX

Abodeposit __-_ -- _ ___-___-. 56 

Abo Formation.............................. IS,

13, 15, 24, 29, 30, 88, 89, 104, 125, 126, 

147,154 

uranium deposits...__.._.._.___.__.______ 88

uranium resources.._..--_-_.______.____._ 147

Acomasag-.. -- -- - -----____ 26,30,61,62,102

Ages of emplacement of deposits. _ _________... 139

Agua Torres deposit._____.___________._--__- 55,106

Agua Zarca Sandstone Member. _16,17,29,89,147,154 

uranium resources.____.._ _______________ 14?

Agua Zarca Sandstone Member and Poleo

Sandstone Lentil _________________ 16

Airborne anomaly 1 deposit __________________ 53

Airborne anomaly 8 deposit. _________________ 53

Airborne anomaly 9 deposit __________________ 53

Airborne anomaly 13 deposit. ________________ 53

Albite ._----.- ----------. 47

Ales deposit------___---_-_------------------_ 47

Alfred Talk deposit._ ____.__._______-____._-_ 50

Alongo deposit ___-..____._--__--___---_____-. 52

Alta deposit.____-_____._____-_-_-_-_--_--_--- 41,61

Altitude of northwestern New Mexico _-_-___- 2 

Ambrosia dome -_-______--___ 26, 30, 61,62,65,68,142

Ambrosia Lake district.____-__-___-----____-_ 2,

4, 6, 60, 62, 63, 69, 71, 72, 73, 77, 80, 

81, 86, 92, 95, 97, 100, 103, 105, 124, 

141,142, 145, 150,151, 152 

color relations of the host rocks.______.--_ 69

intraformational folds in Todilto Limestone.. __-_----__--.-____--------_ 100

mineralogy and form of uranium deposits. _ 63 

ore reserves....____-_--__--.--_______----- 145

stratigraphy,.-_--...____._-_-____---_--__ 60,95

structural features..__--___-_.__________- 61, 100

Todilto Limestone deposits. ______________ 95

uranium deposits_____--_.___.__________ 6,60,92

Ambrosia Lake trend.._-._.___._.____-_--.-_ 65,68

Analysis, purpose and methods. ____________ 107,1S6

Ancestral Rocky Mountains._________________ 16

Anhydrite... ___.-.___._____________.__-_._.._ 137

Animas Formation.______._._ 21,23,24,30,31,62,151

Animas Formation (Upper Cretaceous and

Paleocene)_..-____..-._.__-_-_-_ S3,151

uranium resources---_--_---.__-__-------- 151

Ann Lee deposit.............-......-.----... 38

Anomaly 1 deposit....___..-_-.___--._-._.___ 54

Areas recommended for exploration. ___.._.___ 15S 

Arroyo Penasco Formation............... 10,28,146

Arroyo Penasco Formation, Caloso Formation of Kelley and Silver (1952), 

and Kelly Limestone.___.--_-.___ 11 

Autunite....... 46,48, 53, 55,63,72, 73, 93,104,106,107

Azurite...__.._._...-...._.________.. 32,45,49,55,88

BB deposit..__-_______-_....__-_________--_-- 52

BBB deposit._________.-...-..________.---_-- 52

B and G deposit.. __.__._..._._....---_.----_ 48

Baca basin. _____________________ ____.___.___. 94

Baca Formation.............................. $4,

25,93,94,118,125,126,140,152,154

uranium minerals........................ 93

uranium resources ___.-._.---------.-_.-_. 152

Balo deposit.....................___________^_ 56

Bandolier Tufl............................... 105

Barbara J 1 deposit... -.-.---..----..--..-..-- 35

[Italic page numbers indicate major references]

Page 

Barbara J 3 deposit...-.-......-.....----..... 35

Barite___....______..______._._...._._..____. 63,101

Barton 1 deposit...__.__._.....__._._.___..__. 52

Base-metal deposits in Los Cerrillos district. _ 31 

Basin and Range province.._______ 2,9,26,28,31,119

Beacon Hill deposit.-------_____--___________ 34

Bear Mountains ______________________________ 24

Beautiful Mountain anticline........_.. .... 86

Beautiful Mountain syncline.._______________ 86,154

Becentideposit_.____-__-______._.___._ 43,90,92,105

Beclabito dome. _________-___.__---- __.-___ 83

Begay 1 and 2 deposit. _____.__._._____._..__. 52

BernalFonnation____-______ __..__._.__.. 12,13,147

uranium resources.-.____._________--__-__ 147

Beryl._______________________________________ 47

Beryl prospect_____________________________ 47

Bidahochi Formation._--_______-_____-_--.___ 84

Billy The Kid deposit....____________________ 41

Bismutite- - - 47,107

Black Hawk-Bunney deposit. ________________ 59

BlackJackl deposit.-_____.....___.-___.__--- 42,69

Black Jack 2 deposit... ___._______.._ 42,76,77,80,81

Black ore, Cretaceous rocks.____________ 90,92,140

Gallup district.-..---..---.-.---.-. 77,140 

Jackpile mine_ _________._____ ___--___ 74

Blackshere deposit. ___-____.__--_____--_.-.._ 48

Blanco Basin Formation, age change. _..__._ 4 

Bluewater fault_..____._..____._.___..__... 61

Blue Peak deposit.._._.__.__._..__._.___..__- 37,69 

Bluff Sandstone__._____............ 17,78,29,30,150

uranium resources........................ 150

Bob Cat deposit..____._-__-._.__._--__-_.._._ 36

Somite.... _ -- -- - --- 49,88,125

Bottoms deposit,.___---.______-____.---_.__._ 41

Brookhaven deposit._____.__---__-.__---_.__- 48

Brownlow-Heath deposit.......-...--------.- 56

Brushy Basin Member._______..___--_--__-_- 19,

10, 60, 61, 63, 65, 67, 69, 72, 75, 76, 77, 80, 

81,88,151 

local detail--___-.---___._---_-------_- 60,71,76

uranium deposits................ 60,61,65,69,75

uranium resources_--__-_-__.__........... 151

Bucky deposit_____________________________ 39

Burcar deposit............................... 48

Bursum Formation.-----.----------------.--- 1$

uranium resources___._--_. ___-_._---.-__- 147 

Butler Bros. 1 deposit.-...-__-_..___----_-- 49,104

CD and S deposit-.-..--.-..-.-.-.--.-------. 44

Calotte...--.----- 14,55,63,71,84,87,90,97,101,106

Caloso Formation of Kelley and Silver.. ... 10,28 

Caloso Formation of Kelley and Silver (1952), 

Kelly Limestone, and Arroyo Penasco Formation-....._ ....... 11

Cambrian elastics. .. .._____ _.____...... 28

Cambrian rocks................-.- ......... 10

uranium resources........................ 146

Campbell deposit......___-__...__________ _ _ 54

Canyon 2 deposit.. .....__..... .. ._... 51

Canyon Mulatto deposit__._._.____-_..-___. 38

Canyon View deposit.-- - -____-_--------- 62

Car-Ball 13 deposit..---------- -------- 44

Carbon... .. 20,63,88,95,134,135,136,137,139 

Carbon and Log claims deposit..__._. ... . 47 

Carbonaceous debris....... 88, 90,92,93,94,141,151

Carbonaceous layers__ -_______-.___ . 23

Carbonaceous material-.--..._._._ -_. 14, 

18, 19, 23, 24, 63, 68, 73, 74, 75, 77, 90, 

93,104,105,140,142,151,152 

Carbonaceous sandstone................_. 104,147

Carbonaceous shale. ____ _ __ _ _______________ 6,

7,8,9,21,31,89,90,92,104,151,152 

Carbonized plant debris..................... 87,134

Carl Yazzie 1 deposit _ .__________ _ _______ 50

Carmel Formation.-._-._.__..__..__---_---._ 17 

Carnotite. _______ _ _____________-___ __.____ 5,

43, 47, 48, 53, 54, 55, 63, 83, 86, 88, 90, 

93,101,106 

Carnotite-type deposits. _---.-------------__- 31

Carrizo 1 deposit ______ _-__ __- _ __ .__ 52

Carrizo Mountains. __._.__.--_---.----- 15,26,30,31

Carter-Tolliver-Cook deposit(s) _ __ .. __ 55,106 

Castle T'sosie deposit. _-____-_ -_ -_-__ _- 50

Cave Hills area, uranium minerals_-- -- .- 104 

Cebolla 2 deposit..------------------------ 47

Cedar 1 deposit---.---- --------- -----_--- 58

Centennial deposit__ - -__ ---- - _---_- 33

Cerrillos Hills....................... 26,30,31,93

Cerrillos Hills district........-.-.-- ..... 106

Cerro Colorado-Archuleta prospect.. 32,106,107,141 

Cerro Colorado fault.....- ...---.-----.--.- 119

Chaco slope.-__-_-__------------------ 61,100,103

Chalcocite... 47,49,56,88,125

Chalcopyrite.__-.__-_--.---------- 49,55,88,106,125

Chama Basin. __._____-__-__- _-- _-- 12,

13,14,15,16,17,20,87,95,97,147,150, 

154

intraformational folds in Todilto Limestone. ------------------------ 100

uranium deposits.--.- ---.-----------,-- 95

Chama basin (structural). --_. -_ - -- 26 

Charley 2 deposit.--------------- 55,105,106,145

Charley 2uranium ore grade. __ __ .__.____ 105

Chaves deposit.._ . -------------------- 57

Chemical analyses of elements.............. 107, 126

Chert.--..------------------- 14,15,16,20,23,25

Chill Wills deposit..-..-.------..--- -- 34

Chilton prospect -_. - - - - 53

Chinle Formation..-. _- - ---. - 14,

17, 18, 29, 88, 89, 125, 126, 144, 145, 1*7, 

150,154 

east side of the San Juan Basin ___________ IB

west and south sides of the San Juan

Basin...-------- --------------- 14

lower red member....-.-------.--..----.- 14r IB

Owl Rock Member..-----.--.---.--... 14.15

Petrified Forest Member....__.... - _ 14,15

Shinarump Member..--_..__-. 14, 15,144,145 

uranium deposits. --- -_-- -- - -- 88 

uranium resources......... .. .-.--- 147

west and south sides of the San Juan

Basin..------------_ ---.---_ 14

Christian deposit...------------------------- 43

Christmas Day deposit-_-.........-. ..... 58

Church Rock area, Gallup district _ _-. _ 80 

Church Rock deposit ------------ 44,77,89

Church Rock mine...._-.._-..__.._.-_-.- 75,89 92

Chuska district_ _- __ __ _- _- -. 6, 

8, 19, 84, 86, 87, 95, 97, 141, 142, 144, 150, 

151,154

mineralogy and form of uranium deposits. 86 

stratigraphy_........- . .-. -- 86

structural features.._.. _ __...... 86,97

structural relations of uranium deposits... 87 

uranium deposits...........--... ----..- 84, 95

161
162 INDEX

Page 

ChuskaMountains............. 2,11,12,13,15,19,24

Chuska Sandstone.................... .94, 84,151,152

uraniumresources-- _- _ . 151

Chuska syncline_...........-.....-..._..... 87

Cieneguilla Limburgite of Stearns (1953)..... 25,152

uranium resources-- ...- ._- _ _ 152 

Cleary deposit_-------_.__...-.-...._... 49

Cliff House Sandstone- ----------- 21, «*, 89,105,151

uranium resources......_.-_........_..... 151

Cliffsldedeposlt. - .__ _ 39,105

Climate of northwestern New Mexico_ _..... 2

Coal-...-.----..-------...--.--....-...--...-- 8,

9, 21, 22, 23, 31, 89, 104, 105, 141, 142, 146, 

151,152 

Coalified fragments_.-......_..._._...__. 19,20,24

Coalified logs.------------------. 88

Coalified plant debris.._______________________ 16,

19, 21, 25, 61, 71, 73, 76, 77, 92, 93 

Coaly material... __ -- - 105

CofBnite....-.-.......-..-.-..-.-............. 43,

49, 56, 58, 63, 68, 72, 84, 87, 88, 90, 

101, 104, 106, 124 

Collins deposit.----..-.--...-..--...---- -.. 48

Color relations of the host rocks to uranium

deposits, Ambrosia Lake district- 69 

Gallup district-----_--_------------____ 81

Laguna district. .............-...._..... 75

Colors, favorable, for unoxidized rocks........ 69

favorable, for weathered rocks_-...._.._.. 69

Colorado Plateau-------________ 2,31,69,134,139

Colorado Plateaus province - _ _.. 2, 9,26,28,31,119 

Columbate-tantalates.----_--._---__- _-... 47,107

Columbite. _------_..--..__.-___.__ 47,107

Conglomeratic sandstone and shale, unnamed. 148 

Copper deposits- -.-----.-.-. -... ....... 88

Corral 1 deposit.._-_-.-.....---.....-...._... 46

Corral 3 deposit_____________ _ _______________ 46

Corvusite.----.--------..---_-----__- .-- 43,84,87

Cottonwood Butte deposit--. --- . 52

Cow Springs Sandstone............. 17,18,19,75,76

Coy claims deposit.... ....-.....---.......- 47

Crackpot deposit... __...-_____----.. __. 56

Cretaceous rocks________________ £1, 139,140,144, 151

uranium deposits. -.....____.-..___ _ 89

uranium resources_______-.- . -____.___ 151

Crevasse Canyon Formation... 21, ##, 89,94,104,151 

uranium deposit --...---.-.....-.... 89

uranium resources .-..__--__.-_ _-_..__ 151 

Crinkly zone, Todilto Limestone _---.-._____ 95

Crossbedding in Jackpile sandstone_._ _.. 72 

Cry ptomelane. _----.________- ___---_____ _ 63

Cuba 13 deposit.------------------- 50

Cuchillo Arroyo area - . . _- _- 20

Cuprosklodowskite._ _. _ _ 51,101

Cut-and-fill structures in Poison Canyon sands tone __- __- _ 61

Cutler Formation. .. 12, IS, 14,15, 29,88,89,118,124,

105,126,147,154

contents of lead and copper -- _._ 124 

uranium deposits... _-_-__ _ __ _ _____ 88

uranium resources ____.._-_ __-__ - _ 14?

D 

Dakota Sandstone.-_-_-_.__.-.____-_-__.____. 20,

il, 30, 60, 61, 62, 72, 74, 77, 81,87, 89, 90, 

92, 104, 118, 119, 125, 126, 141, 142, 144, 

145,146,151,154

uranium resources. _ ._... _ .__ 151 

Dalco 1 deposit- -_ _ --.___--__._.____ 35

DaltonPass deposit.__-__ _.______._._ _ _ 44

Datil Formation.-...--___--__- £$,31,94,126,152

uranium resources ___-.-.._--__.____._ 152

Datil-Mount Taylor volcanic field _.._.__.__.. 26,30 

Datil Mountains-.-.....--....--....-..... 22,24,140

Datil section.. . __._.._.._.__..______ 2,23, #4, 26

Datil volcanic field....__.............. 2,9,15,26,72

David Keedeposit. 50

De Chelly Sandstone Member...._..-.__ __ 13,14

Deer Creek deposit....______._.______..__._. 49,104

Defiance monocline........... 26, 30,83,84,86, 87,154

Page 

Defiance uplift.......... .. -. 26,28,30,77,86

Deformation periods in Laguna district ..... 72

Delta deposit, Vernon Pick's discovery....... 5

Delter deposit..-.---------------------------- 44

DennetNezz deposit.. ...... -.. ........ 50

Dennet Nezz 2 deposit__-... .---....... 50

Dennet Nezz 3 deposit__-------_---------- 50

Deposits, base-metal-..........-.-......_...-. 31

Devonian rocks _ 10

uranium resources .......-............-. 146

Diabasic intrusives, relations to uranium

deposits.-..-...... ...... 74,100,103

Diamond 2 deposit..------------- 43,90,92,105,144

Diamond 2mine.-------------------- 89,90,92,140

Dioritic intrusives, Shiprock district_.____-- 84

Distribution of elements, summary and conclusions --.-_- -__--- ---------- 189

in the ores..----------------------------- 107

in the Todilto Limestone 186

Divide25, 26, 27, 28 deposit ---------------- 37

Dockum Formation- . 14,17, 29,88,89,125,126,150 

uranium deposits .. _.._ ._ _ 88 

uranium resources.--..................... 150

Dodge-Begay deposit --____.. -.-.--_.-_.-- 50

Dodge Brothers (Airborne anomaly 2) deposit - 50 

Dodge Brothers (Airborne anomaly 1) deposit- 50 

Dog Incline deposit 34

D og mine _.....-.. ......-.-.------- ----- 69

Doloresite-.------------------------------ 63,84,87

Doris 1 deposit--.--------------------------- 34,105

Dory deposit- . . - 48

Double Jerry deposit- 58

Drag A Ranch deposit.........- .-.- - _- 32

Drainage in northwestern New Mexico -...-.- 2 

Dysart discovery - .- - - 5

Dysart 1 deposit_ - __ 5,39

Dysart 2 deposit --------------------------- 39

E 

E and B 1 deposit.--------------------------- 46

E andB 3 deposit.------------------------- 46

Eagle deposit... --------------------------- 42

Eastside Lease.-..-------------------------- 6,8

Eastside mines._._ . __ . - 81

El C-B and Maxine deposit. -- __ 47 

Elbert Formation.-.....-...... .--...- 10,28

uranium resources. _ -__ 146

Elemental assemblages, summary and conclusions----.-.....----..----.- 126

Elements concentrated between ore and

barren ground. ------------------- 137

Elements in the gypsum unit--.-------------- 188

Elements in the ores, distribution-...-.. . 107 

Elements that decrease in concentration away

from ore _. .- 184

Elements that increase in concentration away

from ore. ___ - - 184

Emplacement ages of uranium deposits....... 189

Emplacement of uranium deposits in northwestern New Mexico.-..--------.- 141

Enos Johnson deposit-_..................... 51

Enos Johnson mme..------------------------- 87

Enos Johnson 1 deposit_.........-.... .... 51

Enos Johnson 1 mine.. _ __ .__ - 87

Enos Johnson 2 deposit... . ._. 51 

Enos Johnson 2 mine.,____...._..._. _ _ _ 87

Enos Johnsons deposit_........-.- . .-.- 50

Entrada Sandstone-17, 29, 95, 101, 118, 125, 126, 150 

lower sandy member.----.-------.------- 17

medial silty member__ ----------------- 17,18

pre-Dakota folds --....__---__- ....... 140

upper sandy member.. ---------------- 17,18

uranium deposits ._ _ 95,101

uranium resources----.--.-------- ._____- 150

Erma 1 deposit . - - 45

Espinaso Volcanics of Stearns (1943) _____ _ 85,

30,106,107,118,119,141,152 

uranium resources,_.-........ _....... 152

Evelyn deposit..-...-..--.-.------------- 41,61

Exploration, areas recommended_............ 15#

F Page 

F-33deposit . - 59,102

F-33 mine--..-.----------..-------.--. 101

Faith deposit. .............................. 35,102

Fault, thrust, Southern Rocky Mountains

province. . .__. - _. - 28 

Faulting, normal, uiarea....__._- .._...._ 31

Santa Fe Group... _____.______ 30 

Faults, thrust..----------..---..-. .- 30

Todilto Limestone...______ _ __..... 100

Feldspar...........................__...... 75,81

Ferroselite....---__---.--._------_..._... 63

Flat Top 4 deposit . .... ............. 35,102

Flowage structures m Cretaceous rocks.. 92,105,140 

Fluorapatite ........ ..-....... 188,139,142

Fluorine.--...---....... -. .-.-. 188,139,144

Fluorite.-.-------- - 37, 4?, 48, 101, 107, 188, 146

Folds, Ambrosia Lake district................ 62, 68

intraformational, Chuska district._____. 100

Todilto Limestone.. .......... 30,100,125

Jurassic rocks ...._............. ... 62

Laguna district_.---...-- -.---.-. --- 72 

monoclinal....----.......-...-.--....--.- 30

Morrison Formation- . ___ . _ - 61 

Tertiary and Quaternary rocks.-.... --. 94

Todilto Limestone_..... ..-..-...... 102

Fort Defiance area ____ ..___ -.__-_ . 15

Fort Wingate_--.----___------------- 15,17

Fossile logs..... . -. .. 73,84,86

Foutz 1 deposit- - - - - 43

Foutz 1 mine. - -- 43

Foutz 3 deposit --.-.-------------------- 44,76,80

Foutz 2 deposit------------------------------ 43

Foutz 2 mine. 43

Fracture filling deposits...__--.-__-_-------- 31,105

Fracture system, Ambrosia Lake district--.- 62,100 

Chuska district _-----.------------------ 86

OaUupdistrict-.--.------------------- 77,92

Laguna district .___ . . . 72,100 

Fractures, control of deposits..---.......-.... 142

Francis deposit ---------------------------- 41,61

Fruitland Formation. _______ 21,23,30, 89,90,126,151

uranium resources..---..... .-....... - 151

Fruitland Formation and Kirtland Shale.. _ _. #8

G 

Galena-,.-------------- 55,101,106,125

Galisteo basin-------------------------- 93,140,154

Galisteo Formation ......... £5,31, 92,126,140, 16i

uranium resources 16%

Gallup district.-----_--.---------------- 6,

76, 77,80, 86,124,140,142,144,150,151 

color relations of host rock;'.--- -------- 81

flowage structures in Cretaceous rocks.... 92

mineralogy and habits of uranium deposits. 77 

stratigraphic and structural relations of

uranium deposits...-------------- 80

stratigraphy-..---...-.--------- ----.--- 76

structural features..... -_ - 77

uranium deposits 76

Gallup sag.-.-------.......- - -- 26,77

Gallup Sandstone..-_--.--.------ il, 22,89,104,151

uranium resources....-.. _ _- _ - 151

Garnet.......... - -- 47,107

Gay Eagle deposit- _ _. - . - 59

Geography of northwestern New Mexico _... _ $ 

Geologic controls of uranium deposits.___ 141 

Geologic history of northwestern New Mexico _ 28 

Geologic nomenclature ----------------------- 4

Geologic setting of northwestern New Mexico. 9 

Ghost Ranch.. 20

Glen Canyon Group. 17

Glorieta Sandstone.... . ..... 12,13,29, 147

Glorieta Sandstone and Yeso Formation.... IS, 147

Glover deposit------------------------------ 41

Grants mineral belt . .- - 146

Grants mining district---------------------- 6

Grantsite.-------------------------------- 101

Green Pick 20 deposit.---------------------- 37

Gummite------------------------------ 47,101,107
INDEX

Page 

Gypsum............. 13,17,84,87,90,95,137,138,139

Gypsum-anhydrite member of the Todilto .. 95,139 

Gypsum unit, elements.... _____________ _ _ 126,188

H 

H. B. Boy 2 deposit......................... 51

Haggite---..-.------..-.--....---._._._.____ 63,101

Hanosh deposit..____. ................. 57

Haystack deposit_........._............. 36,102

Haystack 2 deposit........................... 37,95

Haystack mine............................... 5

Heart 3 deposit............................... 47

Hematite.. __.....________________ _ 69,101

Henry Mountains intrusives.. __._________ 31

Hermosa Formation.......---._.--.._.... 11,29,146

Hermosa, Molas, and lower part of Rico

Formations......._............ 11, 146

Herrera deposit........._....._........__.... 45

Hewettite.. - . . - 84

Hillfoot 1 deposit............................. 45

Hiser-Moore 1 deposit.. __ ._ ._.__ 53,106 

History of mining and ore production. _..____ 5

Hogan deposit..--.---_---_..-.-____________ 33,69

Hogback claims deposit..........__________ 52

Hogback 3 and 4 deposit. __.__.______..___ 43,104

Hogback monocline-..-_.__._.._._- 26,83,84,86,154 

Hogsett-Hust-Henderson 1-4 deposit. ________ 54

Hanosh deposit...___...._-_........__..... 37

Hook Ranch (Airborne anomaly 4) deposit.. _ 54 

Hook Ranch (Airborne anomaly 5) deposit... 54 

Hook Ranch (Jaralosa) deposit.______________ 54

Hook Ranch mine.---._---_-----_---__---_-_ 93

Hopewell Series.._.._.................... 10

Horace and Quemazon deposit_- _ . 57 

Horace Ben 1 deposit._..._-_-__.-_.________ 50

Hornet deposit.. __ 47

Horny Toad deposit....___._-_.-.-.__..__.__. 47

Horse Mesa deposits...._____.__.___._______ 52,81

Hoskey Barton deposit....................... 52

Host rocks, color relations to uranium

deposits. ...............__..... 69

Hot Shot deposit......_.__ ____ 54

Houston deposit.......___. _____ ____ 50

Hust-McDonald-Brown deposit..-___-._____. 54

Ignacio Quartzite of C olorado ________________ 10

Igneous rocks, intrusive, Shiprock district____ 84

relation to uranium deposits_.___ _ 68,93,103,140

Ilmenite......__ _ _ _ ___ 107

Ingerson deposit___.__ _ ____ ________ 58

Intraformational folds..._ __________________ 30,

62, 72,97,100, 102,125,126,142 

Intrusive rocks of varied composition and

form. __ _ __ 25,152 

uranium resources___________.__..._______ 152

Investigations, previous, in northwestern New

Mexico ---____-_______..__________ S

Isabella deposit___ _ __ _ ____________________ 33

Isotopic age dating of La Sal Mountains ______ 31

Jack Boyd deposit. _ _______ _ ______________ 52

Jack Boyd mine........________.________..... 90

Jackpile deposit.............. 5,58, 72, 73, 74,105,142

Jackpile discovery..__________________________ 5

Jackpile mine__ _ ______________________ 6,71,74

Jackpile sandstone.- -_--_-___________-._____ 21,

29,69, 71,72, 74, 75,84, 87,151, 152 

description--._.________._______._______. 71

uranium resources._______________________ 151

Jackpile trough__.__....______._.__________ 152

Jaramillo-Montoya deposit_ _ _______________ 45

Jarosite ._ _ ._ . _ _ 88,90 

Jemez Mountains. __________________ 2,16,26,105,126

Jemez volcanic center_.---__.__-_._._______ 94

Joe Ben 1 deposit...__________________________ 50

Joe Ben2 deposit,....__._.__._.____.__,-.__ 50

Joe Ben 3 deposit......-..-......_-......--.. 50

Page

John Joe 1 deposit..----..-.-...---..--------- 50

Joint control of uranium, La Ventana Mesa. _. 105 

Joint sets, Chuska district..------------------ 86

Joints in Morrison Formation_......._..-. 61

JOL deposit....-__--_-...-.-------._----...-- 48

Jordisite.._-_..-_-.--__--.-..._.-.-.---.--_--- 43,63 

Joyita highlands.......................... 12,89,139

Joyita Hills._._.____......__..__. ..._ 29

Junction deposit_.-..-..-....-..-.-.-.....-. 52

Junior deposit. _ -__._ _--- 36

Jurassic basin of deposition......... 142,143,144,152

Jurassic deformation__ ... 140,154

Ambrosia Lake district............... 68,97,102

Chuska district.-.----------------_... 87

Gallup district..........__-.. -. . 77

Laguna district.... - - 72,74,97

Shiprock district.-_.--._---.--..--.-.-- 84 

Jurassic rocks..... ._.-.- 17,21,139,140,150,152

uranium resources...-.-....--..-.-.--..-- 150

K 

Kaolin..._-...-___.______..____._--------- 64,81

Kaolinite__.____- .__ ________ - 64,71

KeeTohedeposit__________.___ ___ --- 50

Kelly Limestone _.______.____ __--- --- 10,28

Kelly Limestone, Arroyo Penasco Formation, 

and Caloso Formation of Kelley 

and Silver (1952)- _ ____---__- 11

Kiawa deposit. __________.-______ -- - 47

KimbetoT. P. deposit..______.-_-___--__---- 50

King claim deposit_-__.___.-______-_._..__--- 54

King 2 deposit ._......_....-.---.-.-.- 53

King 6 deposit -.-- ._.. . ---- 52

KingTutt deposit.-- .---.---..---------- 52

KingTuttldeposit._ - - -- 52 

KingTutt Point deposit-......---..--------- 52

Kirtland Shale___......... ..___..-- 21,23,30,151

uranium resources____,_______ _--- 151

Kirtland Shale and Fruitland Formation_.. 23

L-bar deposit - - 57

La Bajada deposit. _______,_. 53,105,106,141,142,145

La Bajada uranium ore grade_.__-____-____- 105

La Jara deposit__ _. - - 59

La Joyita Hills.....______.._....______..___-- 12

La Plata Mountains.__________---____-__-_--- 31

La Sal Mountains, isotopic age dating. _.__... 31 

La Ventana Mesa, uranium deposits._-_...... 49,

104,105,142,146 

La Ventana syncline._______ ._____. --_ 105

La Ventana Tongue__-_________.________ 22,105,151

uranium resources________..-__._______.._ 151

Laccoliths of West Elk Mountains ____________ 31

Ladron Mountains.............. ...-.... . 2,11

Laguna district. 6,17,18,20,62, 69, 71, 74, 77, 84,86,87, 

95, 97, 100,103,105,140,141,142,144,145,151,152 

intraformational folds in Todilto Limestone.... ---__--_-_-____---------_ 100

mineralogy and form of uranium deposits. 7% 

stratigraphy ____ _ ________________________ 71, 95

structural features___________.____,______ 72, 100

Todilto Limestone deposits.___-__-__-___- 96 

uranium deposits.._____________ _---_ 69

Laramide orogeny __________________________ 30

Laramide structures_ ____-___.___.._-_____ 100,144

Largo deposit -_ - - - -- 42

Last Chance deposit_____.__..--..----------- 59

Last Chance 2 deposit.-.____________________ 42

Lawrence Elkins deposit.. 42

Lead-uranium ratios__ - ______________________ 69

Leadville Limestone... ___--___________--_--_ 10,28

Leadville Limestone, Caloso Formation, 

Kelly Limestone, and Arroyo 

Penasco Formation, uranium 

resources._________ ________ _ _ 146

Lemitar Mountains_______________________--,_ 11

Lewis Shale--..--.__._____________ 21,««,23,105,151

uranium resources..........._...._ . 151

Liebigite......-..... ...-.-.---- .-- 101

Page

Lignite. ...-..------- -.-.-------- 137

Lime content of uranium ore...-..-.. ..... 60,

71, 75,81,86,88,89,93,95,104 

Limestone member of the Todilto....... 95,139,154

Limonite...... ......-.---..-- 43,54,69,88,90 93

Little Davie deposit .....-... ......-.. 55,106

Logs.... .................. - 14,20,23,87,88

calcified. _------.-------------------- 87

coalified___-------------------------- 88

mineralized - - __- -. - . - 87 

silicified.____--.---_--------- 19,20,23,60,73,88

Lola deposit.- .-_- -- -- ---- 45

Lone Pine 3 deposit-. --_-- - _ - 58

Lone Star deposit - -.. -------- ----- 53

Lookout Point deposit__. .....-..-..... . 51

Los Cerrillos district - .-.......-....- 31,119,141

Los Pinos Mountains-.------------- ------ 2 ,28

Lou deposit-.-----.--------- --------------- 45

Lucero Mesa.- - _....-. - - 12,13,14,15,28

Lucerouplift-.----------------- 26,30,62,77,93,102

Lucky Dog deposit.- - -_ - --- 47

Lucky Don deposit.. -.._ ------------- 55,106

Lucky Strike deposit. _____.__._- - . 45

Lukachukai anticline _ ._ - - 87 

Lukachukai district...... ... 144

Lukachukai monocline.._ .._..-.-..-------- 87

Lukachukai syncline 87

M 

M-6 deposit------------_- ------------------ 57

McCartys syncline..-------------------------- 26,

30, 60, 61, 62,63, 71, 72, 92,100,102,103, 140 

McDermott Formation.___-_____ .... ... 23

McDermott Member. _-_..__.__ ...._----.-- 23,31

McPhaul adit deposit..-_-_--- - 3., 92

Madera Limestone. - __ - -- ---- 11,

12,29,88,106,118, 125, 126,146 147

uranium deposits.. _.__ - .- 88

uranium resources. .- _ . - 146

Magdalena Group. .---------------------- H, 12

Magdalena Mountains...._._-__.-------- 2,11

Magnetite... - -- - 47.107

Malachite...--___._--._._-_----- 32,45,47,49,55,88

Malpais deposit. _._. _- - - - -- 34

Mancos Shale ----------- 21,22,25,31,89,126,151

uranium resources... ..___ ._ - ._ 151 

Manganese mineral-_-_.__ ---- ----- 63

Mangum deposit._.- . - - - 33

Manol deposit __..----- --..--------- - 35

Manzano Mountains.--- ------------------ 2,26,28

Marcasite - -- 43,63,72,101,124 

Marie deposit- - -- .------------------- 55, 1°6

Marquez deposit-..--.--.----.---------------- 34

Mary 1 deposit _,___ --------- 39

Massive zone, Todilto Limestone ------------ 95,97

Manldian deposit...---.-.------------------- 49

Menefee Formation--------- _ 21,««,89,104,146,151

uranium resources. __- ---_-------- 151

Mesa Alta deposit---..----------------------- 46

Mesa Prieta__ -- - - 21

Mesa Top 7 deposit..._ _- - ---- 34

Mesa Top 18 and 20 deposit-__ .__..__---___- 34 

Mesaverde Group..- . - 21,25,89,126 

Mesaverde Group undivided ___ _. 22,89

Meta-autunite-..... . 43, 53, 54, 63,90, 9* 106

Metal, base, deposits-.._._.....-----.---. -- 31

precious, vein deposits.._._.__ ._ -._-- 31 

Metatorbernite _________ ,_ - ----- 106

Metatyuyamunite-_--___- 40,43, 51, 63, 72, 90,101,104 

Methods and purpose of analysis -._ - 107,126 

Methods of study and sources of data.. ..- 2 

Mi Vida, Charles Steen's discovery.__ ..... 5

Mica... . 47,72

Microcline ___. . ---- ------- ------ 47

Midnight 2 deposit---.-----. .------ 33,89

Miguel Creek dome. -------- 61

Mimi 4 deposit..___ - - - 48,106

Mine reserves, the term _---- -- --- 145

Mineralized breccia deposits,...-... -... - 31,105 

Mineralized logs, Chuska district- --. - 87
164 INDEX

Page

Mineralized pipes_ .._.__...____ 105 

Mineralogy, habits, and structural relations,

deposits in igneous rocks. ..._ 106 

deposits in metamorphic rocks_. ___ 107 

Mineralogy and form of uranium deposits,

Ambrosia Lake district_.. ___ OS 

Chuska district........................... 86

Laguna district._...____..._.._.. 7* 

Todilto Limestone_.______..__. 100 

Mineralogy and habits of uranium deposits,

Cretaceous rocks. __..._...... 90

Gallup district.......................... 77

peneconcordant deposits in shale and coal. 104 

Pennsylvanian, Permian, and Triassic

rocks___...__. ........_ 88

sedimentary rocks.-..--.................. 106

Shiprock district..____._...___. 8S 

Tertiary and Quaternary rocks........... SS

Mineralogy of theWoodrow deposit...._.... 124

Minerals, gangue, Chuska district............ 87

Mining district boundaries ................. 6

Mining history and ore production.._....... 5

Mississippian rocks.--....-.._.............. 10

uranium resources.............__.__. 146

Mitten Rock monocline_.__...._..._.. 154

Moenkopi Formation........... 14, 15,17,29,145,147

uranium resources...........__....__. 147

Molas Formation.........._..._..._ 11,29,146

Molas, Hermosa, and lower part of Rico Formations.-.-.-.------.-...----... 11, 146

uranium resources........................ lift

Molybdenite ............................... 107

Monazite -- . - ._. 47,107 

Montroseite ....____.__.___. 63,84,87

Monument Valley, Ariz..............._..... 14,15

Morris-Peters deposit(s)...................... 48

Morrison Formation....-...-.--------..---..- 6,

17, 18, 21, 29, 30, 60, 62, 65, 69, 71, 72, 74, 

75, 77, 81,83, 84,86, 87,88, 89, 90,108,118, 

124, 125, 126, 140, 141, 142, 144, 145, 146, 

150,151,152,154 

Ambrosia Lake district......-.-...--....- 60

color of ore-bearing sandstones............ 75

Chuska district ...---...---...-.-....-- 84

Laguna district..__.. _ __. 71 

maximum thickness............_....... 71

mine reserves_...--.-.-...-----.--..-.- 145

Shiprock district...___.__.... .. . 81

stratigraphy...._._._.......___. 60

uranium deposits._____... 60,65,69,150,154 

uranium resources...................... 150,154

white sandstone unit..........-....---..- 88

Woodrow deposit..___................ 184

Moss Back Member__.-..--...-_---.----.-. 16

Mount Taylor................................ 2,20

Mount Taylor volcanic field.................. 26,63

N

Nacimiento and San Jose Formations, uranium resources._.---.-.--._.. 151 

Nacimiento Formation......... 23, »4, 30,93,126,151

uranium resources...____.......__ 151

Nacimiento monocline. ___.......__... 26

Nacimiento Mountains..____............. 12,29

Nacimiento thrust fault......-...--.....-.. 104,105

Nacimiento uplift-.................. 26,29,30,62,93

Navajo section..._............_.--...... 2

Nelson Point deposit.___._..__...... 51

Nicholson-Brown deposit ..-.----_.-----..- 42

N. Blackshere Ranch deposit................ 48

North Butte deposit........................ 49,104

North Star deposit........................... 47

Nutria monocline.................. 26,30,77,92,105

O

Oak Creek, Shiprock district................. 81

Oak Creek Canyon deposit........_..__. 57

Page 

Ojo Alamo Sandstone....... 21, fS, 24,30,89,126,151

age change .. ....._ ............ 4

uranium resources____............_ 151

Older volcanic rocks of Temez Mountains... _ 25 

uranium resources____.........__.. 15*

Opal.................................. 93,94,95,105

Ore minerals, low-valent..-.-.-.---..--....-. 87

Ore production and history of mining.. _..-. 5 

Ore reserves, the term._._....._..__.. 145

Ore sample groups, exceptional characteristics. 119 

their characteristics..__......_._.. 118

Ore yield from Cretaceous rocks.............. 89

Ore yield from vein deposits.....-....--.----- 105

Organic carbon.......... 18, 134, 135,136,137,139,142

Origin of uranium deposits-.-.----.-----....- 14$

Ortega Quartzite of Just (1937) and associated

rocks........................... 10,146

Ortega Quartzite of Just (1937)..-...-...... 107

Ortega Quartzite of Just (1937) and other rocks,

uranium resources.- ............ 146

OrtizMountains--.----.----.-- 25,26,30,31,93

Ortiz Mountains district.-......-. . - 141

Ouray Limestone. _ __ _ .__...... 10,28

Owl Rock Member-......................... 14

Oxides and silicates of low-valent uranium.... 60

Oxidized suites of minerals.............. 63,68,69,87

Oxidized uranium deposits, Gallup district... 80 

Laguna district--....................... 72

Shiprock district.....--.----.-_------- 83

Oxidized uranium minerals.----.-.. - 74,87

Paguate deposit _. ..... ......._ 57,69,72,74

Paisano deposit__.......................... 56

PajaritoAzul deposit.-..._-----.--._-------- 46

Paleozoic Era.__.....-.. -.-. ..--. . . 28

Paraje deposit__......-.-.--....- .......-- 57

Paramontroseite... . 63,101

Pat deposit-.--.-.--.-- ---------.-- 36

Pedernal highland........................... 12,147

Pegmatite deposits..--....--------.--...-- 31,105

Peneconcordant deposits, ages of emplacement.._____.............._ 139

principal uranium resources . .. .. . 15* 

sandstone..___.___...___....... 60,142

shale and coal...__.____. ... . 10S 

Todilto Limestone and adjacent formations-...-.--..--...--...-.....-- 95

Pennsylvanian, Permian, and Triassic rocks,

uranium deposits -- .- 88,125,139 

mineralogy and habits. -..... ... 90

stratigraphic and structural relations__. 90 

Pennsylvanian rocks ...... .... 11,154

Pennsylvanian sandstone and siltstone....... It

Pennsylvanian rocks, uranium resources.. lift 

Peralta Canyon deposit.___._....__. 49,106

Permian, Pennsylvanian, and Triassic rocks,

uranium deposits............__. 88

Permian rocks......___ .....- .. - li

uranium resources.......-..-..---,.----.- 147

Perthite .... 47

PetacaSchist.. ......... . . 10,107

Petrified Forest Member..-............... 14,15,16

Petrified Forest Member and included Sonsela

Sandstone Bed.............__- 15

Pictured Cliffs Sandstone........... 21,22,28,30,151

uranium resources_..._..__.___... 151 

Picuris Basalts...------....-.-.---...- 10

Pinedalemonocline - - ----------------- 77

Pino Verde deposit-..._.._. .__...... 47

Pioneer deposit_.-............ _........ 56

Pipelike collapse features in sandstones.__.. 30,68 

Pipelike structural features.......... 62,72,105,124

Pipelike structures, Jurassic rocks....--... 62,68,97

Pitchblende..--.-..------.-.--.. 55,90,104,137

Pivot Rock deposit__-----_.....____ 47

Plant debris. .... 12,14,15,16,19,61,88,90,125,134

Plant fragments.............................. 15,20

Plant material............-..-. .... 19,20,84

Page.

Plant remains________. ________ 25 

Plateau-type deposits. . ....__..__.. 31

Platy zone, Todilto Limestone.. ______ 95,97 

Plot 7deposit .... .- .... ...... 52

Point Lookout Sandstone . 21, **, 89,94,104,151 

uranium deposit...___.______... 89 

uranium resources____....____... 151

Poison Canyon deposit_______.._... 34 

Poison Canyon mine...........___...._ 5

Poison Canyon sandstone.._..___ 61,67,68,80 

Poison Canyon trend.._........__........ 65,67

Poleo Sandstone Lentil.... ...... 16,17,29,89,147

uranium resources____.______... 147 

Poleo Sandstone Lentil and Agua Zarca

Sandstone Member._.._...... 16

Popotosa Formation--------------------_.- 25,

31,106,1C7,118,119,126,119,15* 

uranium resources-. .-_.-.. _........ 152

Postfault bodies....---......-.-.-...-.---.-- 68

Postfaultdeposits............ ..-..-....-- 64,65

Postfault mineral assemblages___.. __. _ 63,68 

Postfault ore, Gallup district.. . . 77,92 

Postfault unoxidized deposits........ 64,68,69,74,92

Postmining mineral assemblage............... 63

Potosi Volcanic Group, restricted usage__ 4 

Potosi Volcanic Series. See Potosi Volcanic

Group.

Precambrian rocks...____..__ . 10,88 

Precambrian Era.._____... . .___.. 28 

Precambrian rocks, uranium resources. 1$ 

Precious-metal vein deposits in Socorro

County_______-_.__-. 31 

Precipitation in northwestern New Mexico... 2 

Prefaultdeposits... . .... . . 64,68,77

Prefault mineral assemblages......_.__... 63,68

Prefault unoxidized deposits ............... 69,77

Premining mineral assemblage.. .. 63 

Production of uranium from Todtlto Limestone__.-._------__. 95

Production of uranium ore, 1950-64.. 6 

Prospect 2 deposit______ .__-_ 44 

Puerco Formation.. ........ . 24

Purpose and methods of analyc«s-...--...-. 107,1*6 

Pyrite............ 55,63,69,72,84,88,101,106,124,137

Q

Quartz.-- ......... 14,15,16,21,23,47,55,106,107

Quaternary and Tertiary rnjks, uranium

deposits---- -.-----------...-- 93

R 

RA 1 deposit ............................ 45

RA 2 deposit 45

Radiometric analyses of ores. -............. 107

RanchoAAA deposit -. ----.----.... 47

Rattlesnake deposit.___._..-._ ..... 56

Rattlesnake 6 deposit_____-___ __. 52 

Rauvite______.___._..___ .__ 84,87 

Rayborn prospect..... ... .. . 54

Recapture Member.,--...---. - . - 19, 

20, 60, 63, 68, 9, 71, 75, 76, 81, 84, 86, 

87,144,151,154 

local detail.. .... ... 60,71,76

uranium deposits ----------- 69,75,84,86,87

uranium resources_.. ...... . ... 151,154

Red Basin 1 deposit.---.-..------..---- 32,93,94

Red Basin 2 deposit--... 32,94

Red-bed copper deposits____. ___. __ 88,125 

Red-bed uranium deposits _ . 125 

Red Bird deposit........_. .. .._ 45

Red Bluff 3 deposit............ ............ 58

Red Blufl 6 deposit. 58

Red Bluff 7 deposit....... 59

Red Bluff 8deposit_...- . 59 

Red Bluff 9 deposit_ .. . . 59 

Red Bluff 10 deposit... .... 59

Red Head 2 deposit... . ..... ... .. 45

Red Point Lode deposit.................... 36
INDEX 165

Page 

Bed Rock 3 and 4 deposit..___........... 37

Red Rocks deposit........................... 52

RedWash Point deposit...................... 52

Redco deposit..- -.. ..-_ __-_-_ -____ 37

Redistributed ore..-.___._-._.._......--.__. 65,77

Reed Henderson deposit.......-.._.....___.. 51

Resurrection deposit..........--.-..._.....__ 46

Rey deposit.................................. 45

Rico Formation.................._...... 11,12,29

lower part, Molas, and Hermosa Formations............................ 11, 146

Rimrock deposit........-.._.__.--.__.__..___ 35

Rio Grande trough........................... 9,

13.25,26,28,30,31, 62, 63, 72,93, 94,103,105,106,

119,126,140,141,145,146,147,154

Rio Grande trough and vicinity...-__.._._... 23, SB

Rock-Color Chart, favorable colors for rocks.. 69

Rocks, Cambrianage......................... 10

Cretaceous age........................... $1

Devonian age............................ 10

Jurassic age__._._.._-..._____..______._.- 17

Mississippian age._____....._._.___._.____ 10

Pennsylvanian age..-_._.__.._._______._. 11

Permian age-..-.------.-. 1%

Precambrian age---.--.----.--.--...---.- 10

Tertiary age..._...-.-.._._-__-._-_.____._ 2S

Triassic age.-. ..._-._.__-_-___._.--_-- IS 

Rocky Flats deposit....--.-.-.--.-..-....-... 52

Rocky Flats 2 deposit........................ 52

Rocky mine 2 deposit........................ 52

Rocky Spring deposit.........--..-......--.. 51

Rodlike structures_....__._.__._......__-___. 74

Rogers deposit(s).._____..-.-.._._-.__.___._..53,54

Boll....... ---............-.-.- .---.. 64,84

Sabugalite--............................... 48,107

St. Anthony deposit......___.....______...._. 57

Saint Judedeposit..____._-_...._.._-_.__.... 45

Salitral Shale Tongue.-.-. ..-_-___-._-_._. 16,89 

Salt Canyon deposit,.---......___..___.______ 51

SaltWash Member__.___..---.-.........-.... 19,

81,84,86,87,124,125,126,144,151,154 

local detail.....-- - --- -- -- 81

uranium deposits.--------.--.--------- 81,84,87

uranium resources.........-.---.....-.. 151,154

uranium-vanadium ratio................. 124

Samarskite - ------ - 47,107

Sam Point deposit ------------------------- 52

San Andres Limestone........._.__.___-_.-__ 12,

13, 14,29,106,118, 186, 126,147 

uranium resources......__.__-____-_.---.. 147

San Jose Formation..... 23, $4, 30,62, 93,104,126,151

uranium resources..........---......--... 151

San Juan Basin..-_,._-__...__-..-.__-__---_- 2, 

9,10, 11,13,14,15,17,18, 20, 21,22, S3, 24, 

25, 28, 29, 30, 60. 61, 62, 69, 72, 74, 75, 77. 

81, 83, 84, 86, 87, 89, 90, 93, 102, 104, 105, 

137,140, 142, 143, 146,152 

mineral belt....-_._--_.-..-._--__-----. 146,152

San Juan basin (structural)_..--.-.-...---.. 26,30 

rocks of Tertiary age_................... US

San Juan highlands.-..-.___-------.-.--..-.. 29,89

San Juan Mountains.........-.--.--...-.--... 2,30

San Juan uplift.... ---_____---_---_- 26,28,30,62

San Juan volcanic center.___-_____ __ ___ 94

San Luis-Uncompahgre highland.. _.. _ 12, 88,89,139 

San Luis-Uncompahgre uplift..-.---.-----..- 28

San Mateo dome....-.--._____------.----- 61,65,142

San Pedro Mountains__.._._._-_____--____. 2,

10,11,12, 13,15,16, 26,28,29,93,147 

San Rafael Group.._-________.----...-.---.-. 17,18

Sandia Formation.....---........--..-._. ff,29,146

uranium resources........................ 146

Sandia Mountains.._______........... 2,11,18,25,26

Sandstone and siltstone of Pennsylvanian age. IS 

Sandstone deposit.....----.----------------.. 39

Sandstone deposits of uranium.-------------- 31,39

Sandy deposit.-_-_---.--.....---------------- 56,95

Sandy mine__._--____.__.____-__-_-____--__._ 6

Page 

Sangre de Cristo Mountains............... 10,11,93

Sanostee Wash area__....................... 86

Santa Fe Christ deposit......_........._.. 42,104

Santa Fe Group...... 25, 30,31, 63,93, 94,107,126,152

uranium deposits_...................... 94

Santa Fe Group (Miocene to Pleistocene).... $6,16$

uranium resources........................ 152

Santa Fe Group undivided.___........... 25

Santafeite.................................... 101

Santa Rosa Sandstone.,.___............... 16

Schroekingerite...................... 37,53,54,87,93

Seaway in Jurassic or Cretaceous time...__... 30 

Section 1 deposit(s)._......................... 41

Section 2 deposit(s)..-_...-.-.-._._...._--_... 33,41

Sections2 and 3 deposit._.__-----___._-.----- 39

Section 3 deposit--.--..._-__.--_._._._.._.-.. 35 

Section 4 deposit(s)_-......................... 35,41

Section 4 prospect-..-.-. -- - . 57 

Section 5 deposit(s).----._. ---- -_.-_---_- 33,36

Section6deposit--_.-- -- ------------- 33

Section 8 deposit.-..---------.--..--..--.--.- 44

Section 9 deposit(s)._-__._.______..______-_.._ 44, 59

Section 10 deposit. ---- - - 39

Sections 10 and 11 deposit.__-._..____._._.__ 36

Section 12 deposit._ - -.- - . -- 39 

Sections 12 and 13 deposit......-....-----...- 36

Section 13 deposit(s)................ 33,37,39,42,44

SectionH deposit(s)..-.. -- .. 36,44 

Section 15 deposit. __----_---.----_-_------- 40,69

Section 16 deposit (s).._._.......-..-...-.---.. 33,44

Section 17 deposit(s)_ 36,37,44

Section 18 deposit(s) --------------- 33,36,37,44

Section 19 deposit(s) -----.----------- 36,41,44

Section 20 deposit(s)---------_-_------- 37,44

Section 21 deposit(s).-...-...-..-.... .34,40,41,42,44

Section 22 deposits) ----.---.--------. 36,40,44,69

Section 23 deposit(s)._-._-__.-._._.- 36,40,42,44,69 

Section 24 deposit (s)............. 34,35,37,40,44,69

Section 25 deposit(s)-.__._.._.--.-. 37,40,48,49,102 

Section 26 deposit(s)----__-_-- -______-_.- 38,40

Section 27 deposit(s)..._................... 38,40,42

Section 28 deposit..---._..-.-----.-.-........ 40

Section29 deposit(s)--._.___.---._........... 38,40

Section 30 deposit(s)- ----_---- _-_-.---- 38,59

Section 31 deposit(s).......................... 35,37

Section 32 deposit(s)..._.---_-.--._....-... 35,37,38

Sections 32-33 deposit........................ 42

Section 33 deposit(s)--__.--.----_.._......... 35,38

Section 35 deposit............................ 42

Section 36 deposit (s)...__.._._.--_... 35, 37, 39,41,49 

Sedimentary rocks, vein deposits............. 106

Seleniferous zone, Galisteo Formation........ 93

Selenium-..- ---- --- _ 48,63,93

Shadyside deposit....-....-----.-.........-.. 51

Shadyside 2 deposit.-_ _ -_ . -. 51 

Shaft prospect-...--------------------.-.---- 55,106

Shinarump Member--.--..- 14, 16,17, 29,89,144,147 

uranium resources........................ 147

Shiprock area carnotite deposits.............. 5

Shiprock district......---.--.----...........- 2,

6. 7,19, 83, 84,86,87,141,144,150,151,154 

stratigraphy....-....--_-.---....-...--.._ 81

structural features--.-__._---_-.-.-...-__. 83' 

structural relatio as of uranium deposits... 84 

uranium deposits ......................... 81

Sierra Nacimiento. _- _ 2,10,11,12,13,15,16,26,28,105 

Silicifled fossil logs, Laguna district-......... 73

Silicifled logs..______ __.____.-____.____-.._- 73,88

Silver Bit 7 deposit.---_._.----.__----- 42

Silver Bit 15 deposit . _ _.-- - 42 

Silver Bit 18 deposit-_--_-.___-_-.._._.___-.-_ 42 

Silver Creek prospect. _.-.-.-.-._...-...--.. 54,106 

Silver Spur 1 deposit.._................---. 40

Silver Spur 5 deposit-----.... ._......--.--. 40

Sklodowskite.-_._-..______-..._-___--.-._ 101

Slim Buttes area, uranium minerals_.._- - 104 

Small Stake deposit.... . 40

Smith Lake anticline......................... 61

Sonora deposit__--_ _-_____-___-___---- 56,106

Page 

Sonsela Sandstone Bed.......______ 15,89,1<7

uranium resources---.-----.-..____... 147

Sources of data and methods of study____ 2 

South Butte deposit....-.... ............ 49,1°4

South Mountain....-.-.-.---.-.-...-___... 93

Southern Rocky Mountains province__..... 2,

9,26,28,31,119

Southern San Juan Basin mineral belt_ _.. 146,

150,151, 162

Spectrographic analyses of elements___.. 107, 126 

Sphalerite..---------------------.--------...- 125

Stack ore__ _____... 65

Stacklike bodies....--....'....^.............. 68

State lease deposit-.---------...--.......-... 46,104

Stockworkdeposits.-----.-.................. 31,105

Stratigraphic and structural relations, Cretaceous rocks....__.-.-..__.......-- 90

deposits in sedimentary rocks............. 106

peneconcordant deposits in shale and coal. 104 

Pennsylvanian, Permian, and Triassic

rocks.-...---.---.----...-_..-_-_. 88

Tertiary and Quarternary rocks.. _..... 93

uranium deposits in Gallup district....... 80

Stratigraphic relations of the uranium deposits,

Laguna district-...-.....--.-.-... 74

Morrison Formation...................... 65

Todilto Limestone........................ 10%

Stratigraphy, Chuska district___........... 86

Gallup district..-----.----------..------- 75

Laguna district_--.___-_-------..-.-__-. 71

Morrison Formation...................... 60

Stratigraphy, regional...------------..-.._-.- 9

Shiprock district......-..-.-.---.-....... 81

Todilto Limestone ..................... 95

Structural controls of deposits....... _ ...... 142

Structural relations of the uranium deposits,

Ambrosia Lake district....--.--.. 68

Chuska district -------.---------.------ 87

Cretaceous rocks... ----.------..---.-.-.-- 90

Laguna district...---------.-----..---...- 74

Pennsylvanian, Permian, and Triassic

rocks.-..........--. - -... 88

shale and coal.. ....... .-..-..-.. 104,105

Shiprock district -.---.-.-----------. 84

Tertiary and Quaternary rocks...... 93

Todilto Limestone.__.... .. ......... 10$

veins - -.-- 106,107

Structure, Chuska district-._ ._ - 86 

Gallup district....---.--.--------------- 80

Laguna district..-.--.. ..-----. .------ 72

Morrison Formation...................... 61

northwestern New Mexico......... .- 25

peneconcordant deposits in Todilto Limestone- - --. _ - . ------ 97

Shiprock district.-.,....------.--------. 84

Summerville Formation...................... 17,

18, 29,30, 95,97,100,101,126,147,150 

uranium deposits.__......._....... 95,101,150

uranium resources........................ 150

30-C deposit.._.. .. . _ . 35

TJBD 1 deposit... - 46

T2 deposit-..-.-..--..--...-.-......-..... 42

T lOdeposit. - - 42

Taffy deposit---.-----------.-------...-..-- 59

Tapeats Sandstone of Arizona................ 10

Tectonic activity in San Juan Mountains area. 30 

Tectonism, related structural features........ 30

Temperature range in northwestern New

Mexico.. _ -_- .__ 2 

Tent deposit-..-.__-__..__.--. _....._._ 51

Tertiary rocks.......___............. gS, 139,140,151

uranium resources.......... ............ 151

Tertiary and Quaternary rocks, uranium

deposits.--___.-__.--_... 83,139,140,141 

mineralogy and habits, _. _ _ _ ------------ 93

Stratigraphic and structural relations -.... 93

Tesuque Formation, uranium content. ____. 95
166 INDEX

Page 

Tesuque Formation, uranium deposits....... 94

Tex-N deposit_.......______._...... 49

Thrust fault, west margin of Southern Rocky

Mountains province..--.---_.__ 28 

Thrust faults................................. 30

Toadlena anticline.._________..._. 87 

Todilto Limestone_._.__..........__ 5,

17, 18, 29, 30, 62, 72, 74, 95, 97, 100, 101, 

118, 1X5, 126, 134, 135, 137, 138, 139, 142, 

144,145,146,147,150, 154 

distribution of elements.................. 1X6

gypsum unit.............. 18,95,97,126,138,139

intraformational folds_ .._.. 30,62,72.97,150 

limestone unit................. 18,95,97,126.154

peneconcordant deposits........_......... 96

structural relations of deposits.......... lOi, 144

uranium deposits. ................ 101,152,154

uranium resources.-...__... . .... 160,154

Tom 13 deposit........... ................. 58

Tom Elkins deposit _.................... 42

Torbernite.................... 48,49,65,104,106,107

Torrejon Formation.._.___.............. 24

Townsite deposit...__..................... 57

Trejoand Sanches 1 deposit...___...._.. 47

Trend ore.................................... 64

Trend type deposits..............._.___. 64

Triassic, Pennsylvanian, and Permian rocks,

uranium deposits..__.......... 88

Triassic rocks................................ 13,147

uranium resources........................ 147

Tusas deposit.--.------...-....__......... 48

Tusas Granite........................... 10,107,141

Tyler deposit...---.-.-....................... 50

Tyuyamunite...__...._.........._..... 33,

43, 50, 51, 54, 55, 56, 63, 72, 83, 86, 88, 90, 

101, 106

U 

UDC 1 deposit............................... 59

UDC Bdeposit . _ 59

Unknowndeposit(s)._..................._ 51,53

Unnamed deposit(s).__..._..._........ " 32,

33, 35, 37, 41, 42, 44, 45, 46, 48, 49, 51, 54, 

56, 57, 58, 59

Unnamed shale, siltstone, and sandstone unit. 16 

Unoxidized suites of minerals.......... 63,68,87,101

Uraninite................,._..__._._._..._... 43,

47, 56, 63, 68, 72, 80, 84, 87, 88, 101, 104, 

106,107 

Uranium deposits, Abo Formation........... 89

ages of emplacement...................... 189

Ambrosia Lake district................... 60

Brushy Basin Member....... 60,61,65,69,75,80

Chuska district........................... 84

color relations of the host rocks........ 69,75,81

Cutler Formation.....__.............. 89

definition__.....___......_........ 31

Entrada Sandstone__.._...........'.. 18

establishing ages of emplacement......... 30

flanks of Ambrpsia dome................. 26

form. .... 6S, 72,80,84,86,88,90, 93, 100, 102,104

Oallup district.-.-....--........-.....--. 75

general types..------_........_..__ 31

habits.. 64, 74,77,83,87, 88,90,93, 10S, 104,106,107 

igneous rocks..--_._..--...--..-...... 106

metamorphic rocks.-----.---.-.--.---.--. 107

influenced by structures.................. 62

Jackpile sandstone_................... 71

Lagunadistrict...-.....-..-.....----.. 69,72,74

mineralogy.-----.-..._-..-____,___-__..__ 6S,

72,77,83,86,88, 90,93,100,104,106,107

Uranium deposits Continued Page 

Morrison Formation. .............. 18,60,65

Nacimiento Formation__.......____ 93

northwestern New Mexico... ____ _. SI 

other districts or areas ..... ........ 87

peneconcordant type...........____. 31

Pennsylvanian, Permian, and Triassic

rocks............................. 88

Poison Canyon sandstone._._..._.. 61 

primary...................... 68,74,102,140,143

Recapture Member....----....---.- 60,75,86,87

relations to host rocks....-.....--.--...-- 28

relations to igneous structural features. 28, 74, 140 

relations to sedimentary features....... 28, 61, 74

relations to tectonic features....... 28,62,68,102

Salt Wash Member.-.-.--..-.--------.--- 84

Santa Fe Group._...................... 94

San Jose Formation-....-.-----------.--- 93

sandsto ne. -..---....--...-..-------..--.- 60

shaleandcoal 103

Shiprock district. _----------------- 81,84

stratigraphic relations..---...--.----_-... 66,

74,80,88,90,93, J0«, 104,106 

structural relations...........--..--...... 68,

74, 80, 84, 87, 90, 93, 10X, 103, 104, 

105,106,107 

Todilto Limestone..-.--.........------ 101,154

vein type__.--______--..-.....--.-----.- 31

veins.................................... 105

Westwater Canyon Member.. 60,65,68,69,75,80 

Uranium mills........................ --... 9

Uranium mine reserves ......... ..... 146

Uranium mineralogy of peneconcordant

deposits....._.... . .__... 60

Uranium minerals, oxidized..... OS, 72,74,84,92,101

primary......- ........ 60,72,88,92,101,104

secondary.-...-.-..--.....-.-- 90,101,104

Uranium ore bodies in conglomeratic sandstone...._.- .. .-- - 14

Uranium ore from shale and coal............. 104

Uranium ore from the Todilto Limestone. .. 95 

Uranium ore from vein deposits.............. 105

Uranium ore grade from Woodrow mine...... 105

Uranium ore lime content- 60,71,75,81,86,89,95,104 

Uranium ore shipments from Cutler Formation.. .---.- .------.--- 88

Uranium ore shipments from Tertiary and

Quaternary rocks...... ..... 93

Uranium ore yield from Cretaceous rocks..... 89

Uranium ore yield from Dakota Sandstone... 104 

Uranium ore yield from Todilto Limestone... 95 

Uranium prospect 17. _.........-.-.....,-- 55

Uranium resources.....__-. -._._ ._ . 145

principal, in northwestern New Mexico... 15g 

Uranium vanadate, Gallup district-........ 80

Uranium vanadates of oxidized suite of

minerals.......................... 63

Uranium-vanadium ratios, Ambrosia Lake

district...--.-----.......--...- 60

Chuska district.. .................... 84,87

Cretaceous rocks.._.....__._...._ 59,90

Gallup district................ . ....- 75

Laguna district_...........__......... 71,72

shale and coal............................ 104

Shiprockdistrict........................ 81,84

Tertiary and Quaternary rocks........ _ 93

Todilto Limestone.....--.-..---.-.-.-- 95

vein deposits.-..__._._.- .__. - -._ 105 

Uranophane.............. 43,49,55,72,87,90,101,106

Uranylvanadates.. ............ 68,69,83,106,141

V Page 

Vallecitos Rhyolites......................... 10

Vallescaldera................................. 26,28

Vanadates, high-valent uranium___.___ 60 

uranyl.____-_. ..... __.. 83

Vanadium-bearing mica and clay....._ __ 72

Vanadium clay.... -...-........ ...... 84,101

Vanadium minerals __...__ .. 63 

Vanadium oxides, low-valent.._............ 68

Vargas-Jaramillo deposit... ..... ....... 47

Varnum deposit __ ..... ..... 33

Vegetation in northwestern N^w Mexico. __. 2

Vein deposits, ages of emplacement___. __ 141

definition................................ 31

habits....... ..._...--. .- 106,107

in igneous rocks.__...........__.... 106

in metamorphic rocifs.................... 107

in sedimentary rocks__..... ...... 106

mineralogy..--...-- -....---.-- 106,107

stratigraphic and structural relations..... 106

structural relations... ........ ... 106,107

Volcanic activity in east-central part of area.. 29,30 

Volcanic rocks, older, of Jem?z Mountains.. t6,15X 

Volcanism in San Juan Mountains area. _... 30

W 

Walker dome..--.--..-..-----.------- 61

Warm Springs.----.-..--.----...--.------- 20,21

Wasatch Formation, west-central Colorado. 31 

Wasson deposit. --......-...-.--..-.--....-- 46

We Hope 4 deposit........................... 48,93

West Elk Mountains laccolith^................ 31

Westwater 1 deposit........... .- ..- 43

Westwater Canyon Member.................. 19,

60,61,63,65, 67,68,69,71, 75, 76, 77, 80, 81, 

88,90,151 

local detail.. -.-.-.------- 60,71,76

uranium deposits ..- 60,65,68,69,75, 

uranium resources__....... .. 151

Whitecap deposit. ---. - -- 35 

White sandstone unit__.....____....... 88

Whitefio deposit. 46

Wilcox Ranch deposit... _..... ...... 57

Windwhip deposit........---.. . 57

Wingate Sandstone.......--....... 14, J7,18,29,150

lower reddish-brown silty member... 17 

upper reddish-brown sandstone member.. 17 

uranium resources._.._.... ........ 150

Wood, coallned---- 24

silicifled..------.--.-.-------- 23,25

Woodrow deposit.--. 58,69,1?5,106,118,119, 184, 126 

Morrison Formation... ... ....... 124

uranium ore grade__ . - 105 

Woodrow pipe, occurrence of ore. ......... 74

YeUow Bird 2 deposit...-...-- .. -.-- 46 

Yeso Formation . - 12,13,29,89,147 

Yeso Formation and Glorieta Sandstone... 13, 147 

uranium resources....-----.- - ----.--- 147 

Young prospect_...._..----..----.-..-.- 47

Zeunerite 104

Zia deposit.......--. . .. 59,95

Zia mine------__..__.-----._.__._ 6

Zuni highlands-_. .._ ... ... 12,89,139 

Zuni Mountains....... 2,10,11,12,13,14,15,17,22,28

Zunlsag 30

Zuni Sandstone-..--.. .. ............ 17,18,29

Zuni uplift.... _. 26,28,29,30,61,62,75, 76,77,102,103

U.S. GOVERNMENT PRINTING OFFICE : 1969 C 329-381