GEOLOGICAL SURVEY CIRCULAR 354

A RECONNAISSANCE FOR URANIUM

IN NEW MEXICO

1953

This report concerns work done on 

behalf of the U. S. Atomic Energy 

Commission and is published with 

the permission of the Commission.
UNITED STATES DEPARTMENT OF THE INTERIOR 

Douglas McKay, Secretary

GEOLOGICAL SURVEY 

W. E. Wrather, Director

GEOLOGICAL SURVEY CIRCULAR 354

A RECONNAISSANCE FOR URANIUM IN NEW MEXICO

1953

By Roy L. Griggs

This report concerns work done on 

behalf of the U. 3. Atomic Energy 

Commission and is published with 

the permission of the Commission.

Washington, D. C., 1954

Free on application to the Geological Survey, Washington 25, D. C.
109°

Cerrillos^ Tec^lote

01" ** ^LasVegos area

SAN MIGUEL

 34?

 33°

 32e

109° 107 106* 105' 104'

50 0

I I I I I

100 Miles

Figure 1. Index map of New Mexico showing areas examined.

ii
A RECONNAISSANCE FOR URANIUM IN NEW MEXICO

1953

By Roy L. Griggs

CONTENTS

Page

Abstract. .................................... . 1

Introduction................................... 1

Datil area...... . .............................. 1

Geography .............................. 1

Geology.......... .....................I.. 3

Stratigraphy............................ 3

Structure............................... 3

Uranium deposits........................ 3

Origin.................................. 5

Page

Cerrillos mining district ...................... 5

Glorieta district ............................. 5

Tecolote district ............................. 6

Las Vegas area .............................. 6

Colfax sill area .............................. 6

Radioactivity and chemical analyses of samples

collected........................ .. ........ 7

Literature cited ............................. 9

ILLUSTRATIONS

Page

Figure 1. Index m ap of New Mexico showing areas examined.............................................. ii

2. Geologic map of Datil area, Catron and Socorro Counties, New Mexico........................... 2

3. Diagrammatic cross section of the northern part of the Datil area showing stratigraphy, structure,

and deposits of uranium minerals ........................................................... 4

ABSTRACT

In the fall of 1953 a reconnaissance for uranium 

was made in the Datil area of west-central New Mexico, 

and in the Cerrillos mining district, the Glorieta and 

Tecolote districts, and the Las Vegas and Colfax sill 

areas of north-central to northeastern New Mexico. 

Traces of radioactive materials were detected at many 

places, and deposits of uranium minerals, which may 

be of possible economic significance, were found near the 

village of Datil. Small amounts of uranium are widespread in sandstone beds in the Mesaverde formation. 

The sample of highest grade contained 0.056 percent 

uranium.

INTRODUCTION

During the fall of 1953 the writer made a reconnaissance for uranium in several areas of New Mexico. 

The work was undertaken on behalf of the Division of 

Raw Materials of the U. S. Atomic Energy Commission 

and was a continuation of investigations begun in New 

Mexico in 1951 by Bachman and Read (written communication, 1952). Some of the areas were selected 

for examination in 1953 as a result of the work of the 

1951 and 1952 investigations.

The several areas examined are in west-central 

and north-central to northeastern New Mexico (fig. 1). 

Most of these areas showed evidence for the occurrence

of uranium, and the area in west-central New Mexico, 

may contain deposits of economic significance near the 

village of Datil.

Each area was traversed by automobile and on 

foot; portable scintillation and Geiger counters were 

used as detection equipment. Possible source and 

receptor rocks were examined and sampled, and the 

samples were analyzed by the Denver laboratory of 

the U. S. Geological Survey.

DATIL AREA 

Geography

The Datil area is in eastern Catron and western 

Socorro Counties, in the west-central part of the state; 

the village of Datil is a short distance northeast of the 

geographic center of the area (fig. 2). The area is a 

highland surrounding a large depression, the Plains of 

San Augustin, that trends northeastward, and lies just 

inside the southwestern margin of the Colorado Plateaus. 

The highland is in several stages of dissection. In some 

places it is mountainous, and in others it is a gently 

sloping plateau. The Plains of San Augustin, a closed 

depression, is covered by Quaternary deposits.

Most parts of the area are accessible from 

U. S. Highway 60, State Route 12, and several secondary roads.
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QUATERNARY
Relatively little is yet known of the regional geology. The rocks of the area are in large part of 

volcanic origin and are of late Tertiary age, but Upper 

Cretaceous and lower Tertiary sedimentary rocks are 

present at the northern tip of the area, and Quaternary 

alluvium is widespread within the Plains of San Augustin. 

Locally, some Quaternary basalt also is present.

Stratigraphy

The Upper Cretaceous and lower Tertiary rocks 

at the northern tip of the area belong to the Mesaverde 

and Baca formations (fig. 2). The Mesaverde formation 

is by far the more extensive of these two units, and 

where examined, it consists of two general types of 

rocks. A lower part is at least 250 feet thick, is 

undifferentiated into members, and is composed mainly 

of dark carbonaceous shale and grayish sandstone. The 

shale commonly weathers greenish gray. The upper 

part of the formation, is a distinct member about 

300 feet thick and composed mainly of light-gray to 

gray sandstone, which weathers greenish buff and forms 

prominent cuestas. Carbonaceous shale, interbedded 

with the sandstone, generally occurs as relatively thin 

lentils.

The Bac a formation of early Tertiary age is exposed between outcrop bands of the Mesaverde formation and the Datil formation. It lies disconformably 

on the upper part of the Mesaverde and is composed of 

an alternating sequence of beds of gray sandstone and 

maroon shale. The unit has a thickness of about 

1, 000 feet.

An angular unconformity separates the Datil formation, of late Tertiary age, from the underlying 

Mesaverde and Bac a formations. The Datil is composed dominantly of rhyolitic materials. The lower 

part is made up mainly of water-washed and water-laic 

silt, sand, and gravel, which is more or less admixed 

with tuff ace ous debris. 'The upper part is made up 

mainly of weldedituff but contains some associated 

rhyolite extrusives.

Quaternary deposits of unconsolidated material 

cover much of the Plains of San Augustin, and Quaternary basalt flows underlie local areas.

Structure

The structure of the area is generally simple. 

The Mesaverde and Bac a formations at the north end 

of the area generally dip from 2 to 10 degrees to the 

south and southwest. Above the angular unconformity 

that truncates the underlying formations the volcanic 

rocks of the Datil formation are nearly horizontal. 

North of the Plains of San Augustin, however, these 

rocks dip about 1 to 2 degrees both to the north and to 

the south, and south of the Plains of San Augustin they 

dip about 2 degrees to the south. Normal faults are 

present along the margins of the Plains of San Augustin, 

although the faults are largely concealed by alluvium. 

Beds of welded tuff that are downfaulted to low elevations 

in the interior of the plains, and rhyolite domes in the 

interior and at the margins of the plains suggest that 

this prominent closed depression is a collapsed

structure related to the eruption of the associated 

welded tuff.

Uranium deposits

Uranium minerals in the Datil area were noted 

first by Mr. Jeff Tietjen, a local rancher, who found 

radioactivity in several localities in the winter of 

1951-52.

Uranium occurs in traces in some of the rocks of 

the Datil formation, but the J>est deposits are in the 

upper part of the Mesaverde (fig. 3). Uranium was 

detected in this cuesta-forming sandstone unit at 

several localities in a narrow belt north of and parallel 

to the contact of the Mesaverde and the overlying 

Datil formation. These localities are in T. 2 N., 

Rs. 10 and 11 W. (fig. 2) and are distributed along the 

outcrop of the sandstone member for a distance of 

about 10 miles. Uranium may occur at other localities 

in this same belt of outcrop, which extends to the 

southeast and to the northwest of the known uraniumbearing areas. The total length of the belt in the 

sandstone member may be about 15 miles. Uranium 

may also occur in the sandstone downdip to the south 

beneath the Baca and Datil formations and updip to 

the north. The Baca formation is another possibility. 

This lower Tertiary unit, overlain with angular unconformity by the Datil formation, may have transmitted uraniferous solutions, and uranium minerals 

may have been precipitated in places where conditions 

were favorable.

In the Mesaverde formation these uranium minerals are generally localized at the contact of beds of 

sandstone and shale, and the highest grade material 

lies in the basal parts of those sandstone beds that 

lie directly above shale beds. Less intense radioactivity indicates that uranium minerals are present 

in the uppermost few inches of the underlying shale. 

The zone of most intense mineralization generally 

ranges in thickness from a feather edge to about 

3 inches. The best deposit found thus far is not of 

commercial grade. The two best samples (nos. 2 

and 3a) contain 0. 056 and 0. 042 percent uranium respectively. However, little is known of the lateral 

extent of mineralization in any given deposit, owing to 

the reconnaissance nature of the survey, and because 

the mineralized zones are largely covered by talus.

The uranium minerals appear to be of the carnotite type and are associated with organic material 

and llmonite. At most localities the organic material 

consists of carbonized leaves and twigs, or disseminated plant remains. Some beds of sandstone appear 

to be oil stained. The limonite occurs as thin films 

or layers deposited along the bedding plane between 

mineralized sandstone and the underlying shale. At 

several localities the limonite contains radioactive 

material, and at two localities it is associated with a 

yellow uranium mineral.

Field-counter measurements indicate that the 

oldest parts of the Datil formation, the water-washed 

and water-laid silts, sands, and gravels and the older 

welded tuffs, are essentially nonradioactive. The 

youngest rocks of the Datil formation, however, such 

as the younger welded tuffs and the rhyolite domes, 

are radioactive and contain traces of uranium.
South 

1 i l i

Datil / formation ' ^ 

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1.1

. ' * *Rnrn fnrmntinrT" " . . 

' ^_3 Mineralized sandstone 

member of Mesaverde formation . .

^H_i -i-r"Mesaverde " formation u

EX PLAN AT I ON

Welded tuff Sedimentary tuffaceous debris Gravel Sandstone Shale 

Figure 3. Diagrammatic cross section of the northern part of the Datil area showing stratigraphy, structure, and 
A sample from locality 13 (fig. 2, and p. 7) is considered to be representative of the younger welded tuffs'. 

This sample (no. 13) contains 0. 003 percent equivalent 

uranium and 0. 0006 percent uranium. Samples from 

the rhyolite domes at localities 11, 14, and 15 all 

contain 0.003 percent equivalent uranium, and 0.0005, 

0. 0006, and 0.0011 percent uranium, respectively.

The uranium minerals in the sandstone member of 

the Mesaverde formation probably were deposited by 

ground water after the consolidation of the sandstone and 

associated shale. Deposition by ground water is indicated by (1) the occurrence of mineralized zones in 

sandstone directly above beds of impervious shale, and 

by (2) the apparent lack of a relation of the mineralization to a fracture system. The characteristic occurrence of a thin crust of limonite along bedding planes 

between mineralized sandstone and'under lying shale 

beds indicates that the rocks were consolidated before 

formation of the limonite, although the limonite may be 

pseudomorphous after a parent iron-bearing mineral. 

Field-counter measurements show that the limonite 

invariably contains some uranium, and at two localities 

the limonite is closely associated with a yellow uranium 

mineral. At one of these localities the uranium mineral 

impregnates the basal part of a sandstone bed directly 

above a limonitic crust. At the other locality the 

uranium mineral occurs as irregular stained patches 

within the limonite. The uranium mineral may have 

been deposited at the same time as the limonite or 

later.

Descending meteoric waters may have leached 

radioactive material from tuffaceous rocks of the 

Datil formation and carried and deposited it at its present locations in the Mesaverde formation. The belt of 

known mineralization is closely associated with the 

tuffaceous rocks of the Datil formation that rest with 

angular unconformity on the mineralized sandstone 

member of the Mesaverde.

CEKRILLOS MINING DISTRICT

The Cerrillos mining district is in the Cerrillos 

Hills in west-central Santa Fe County, about 15 miles 

southwest of the town of Santa Fe. The district has 

been relatively unimportant as a metal producer but 

has been intermittently active for a long time. Silver, 

lead, zinc, and a little copper have been produced since 

1879, and turquoise was mined by the Indians before 

the arrival of the Spaniards. The value of minerals 

produced between 1904 and 1928 amounted to about 

$175, 000 (Lasky and Wootton, 1933, p. 95).

The mineralized parts of the district are associated with a group of small intrusives of monzonitic 

composition that have invaded sedimentary rocks of 

Late Cretaceous and early Tertiary age. Most of the 

deposits are localized in steeply dipping shear zones 

that cut the intrusives (Lindgren, Graton, and Gordon, 

1910, p. 167). Silver-bearing galena, sphalerite, and 

chalcopyrite are the chief ore minerals.

The reconnaissance survey of the district found 

little radioactive material associated with the leadzinc minerals. However, a low level of radioactivity

in the district, was found invariably to accompany a 

type of alteration that is best developed in association 

with the turquoise deposits of the area. Rocks affected 

by this type of alteration are readily recognizable as 

white to light-gray, and by the presence of kaolinite(?) 

and fine-grained silica. These altered rocks are found 

along shear zones that cut some of the intrusives and 

in highly fractured ground adjacent to the shear zones. 

The reconnaissance examination suggests that the areas 

of altered rock may be found only in a fine-grained gray 

latite. The areas of greatest alteration were seen at the 

2 abandoned turquoise mines in the district. One mine 

is in the southeastern part of the district in sec. 5, 

T. 14 N., R. 8 E., and the other is in a low hill to the 

northeast of the main part of the district in sec. 21, 

T. 15 N., R. 8 E. A sample (no. 16) of altered 

material taken at the first mine contains 0.003 percent 

equivalent uranium and 0. 0009 percent uranium. 

Turquoise (no. 16a), hand separated from the sample, 

contains 0. 002 percent equivalent uranium and 

0. 0007 percent uranium. Two samples were collected 

at the other mine in the northeastern part of the district. Both contain small amounts of turquoise. One 

sample (no. 18) contains 0. 009 percent equivalent 

uranium and 0. 0085 percent uranium, and the other 

(no. 19) contains 0.007 percent equivalent uranium and 

0. 001 percent uranium. A sample of relatively unaltered intrusive rock from this locality contains 

0. 003 percent equivalent uranium and 0. 0005 percent 

uranium (no. 20). Rocks at other localities are less 

altered, for example, at the old Evelyn mine in sec. 19, 

T. 15 N., R. 8 E., where the alteration is associated 

with oxidized copper minerals. A sample (no. 21) 

from this mine contains 0. 005 percent equivalent 

uranium and 0.0007 percent uranium.

Two other samples were collected in the district. 

No. 17 is a sample of a relatively fresh, mediumgrained monzonite and was collected from the dump 

of the Cash Entry mine in sec. 5, T. 14 N., R. 8 E. 

It contains 0. 002 percent equivalent uranium and 

0. 001 percent uranium. Sample no. 22 was taken in 

sec. 8, T. 14 N., R. 8 E. at locality 22 where 

Mancos shale is in contact with one of the intrusive 

bodies. The slightly altered shale contains 0. 002 percent equivalent uranium and 0.0004 percent uranium.

GLORIETA DISTRICT

The Glorieta district lies near the village of 

Glorieta in east-central Santa Fe County, about 

15 miles southeast of the town of Santa Fe. The 

northern part of the district is a part of the rugged 

terrain at the southern end of the Rocky Mountains, 

and the southern part is a part of the top of Glorieta 

Mesa, a prominent plateau immediately south of the 

mountains. The surface rocks are sedimentary rocks 

of Pennsylvanian and Permian age that are folded into 

a broad, southerly plunging syncline in which dip of 

the strata ranges from about 10 degrees in the northern 

part to about 5 degrees in the southern part of the 

area (Read and others, 1944).

Iron and copper ores were mined in the district 

about 1900. About 3, 500 tons of iron ore was shipped 

from the Kennedy mine in the southern part of the 

area (Kelley, 1949, p. 197), and perhaps a few 

hundred tons of copper ore was shipped from prospects 

in the northern part of the area. At the Kennedy mine,
in sec. 23(7), T. 15 N., R. HE. on Glorieta Mesa, 

the ore minerals are limonite and hematite that occur 

in a re placement deposit in sandstone in the San Andres' 

formation. The ore body is tabular and dips about 

5 degrees to the west, and where mined it averaged 

about 3 feet in thickness. The abandoned workings consist of a small opencut and several hundred feet of 

tunnels and rooms.

The copper ore was mined from redbed copper 

deposits in the Sangre de Cristo formation that crops 

out mainly along La Cueva Creek in the northern part 

of the district. Chalcocite, malachite, and azurite 

are disseminated in arkose beds in the lower part of 

the Sangre de Cristo formation, which dips about 

10 degrees to the west.

Samples were collected at two localities in the 

Glorieta district. A grab sample (no. 24) of hematite 

ore from the Kennedy mine contains 0. 001 percent 

equivalent uranium and 0. 0005 percent uranium. A 

grab sample (no. 23) of copper ore from a 3-foot bed 

of arkose in sec. 14, T. 16 N., R. 11 E. contains 

0. 002 percent equivalent uranium and 0. 0004 percent 

uranium. Copper prospects in Glorieta Canyon are 

not radioactive and were not sampled.

TECOLOTE DISTRICT

The Tecolote district lies in western San Miguel 

County, about 10 miles southwest of Las Vegas. The 

exposed rocks are, in ascending order, the Magdalena 

group of Pennsylvanian age, the Sangre de Cristo 

formation of Pennsylvanian and Permian(?) age, and 

the Yeso and San Andres formations of Permian age. 

Along the western margin of the area these rocks form 

a steep, easterly dipping monocline, but over the 

greater part of the area they are nearly horizontal 

(Read and others, 1945; Northrop and others, 1946).

The district has several abandoned prospects 

and two abandoned mines that were worked for copper 

about 1900 and again during the First World War. 

The deposits occur in arkose beds in the Sangre de 

Cristo formation. The ore minerals are chalcocite, 

bornite, malachite, and azurite (Lindgren, Graton, 

and Gordon, 1910, p. 116-123).

In 1953 several of the abandoned prospects were examined for radioactivity. All prospects examined are 

within the boundaries of the Tecolote Grant, most of them 

on a hill about 1 mile north of the village of Santana. Other 

prospects visited are about half a mile east of Santana, 

about 1 mile west of Tecolote, and about 2 miles northwest of Tecolote. No samples were taken from the prospects, as very little radioactivity was noted.

One of the abandoned mines, the Blake mine, was examined. It is in sec. 8, T. 14 N., R. 15 E., alongthe monocline in the western part of the district. At this place an 

arkose bed about 10 feet thick has been mined for a distance 

of about 250 feet along the strike and for adistance of about 

25 feet down the dip. Asample(no. 26) of copper-bearing 

rock collected from the dump contains 0.003 percent equivalent uranium and 0.0004 percent uranium.

Two other samples were collected in the Tecolote 

district. One was from an area of greenish rock in an

arkose bed at a place a quarter of a mile west of 

Tecolote. Although no copper minerals were observed 

at this place, a fie Id-counter measurement was higher 

than those at any copper prospect in the district. This 

sample (no. 25) contains 0. 002 percent equivalent 

uranium and 0.0003 percent uranium. Another sample 

was taken from a 2-foot bed of coal in the Madera 

limestone in sec. 8, T. 14 N., R. 15 E. A channel 

sample (no. 24) of this coal contains 0. 001 percent 

equivalent uranium and 0. 0004 percent uranium.

LAS VEGAS AREA

Triassic, Jurassic, and Cretaceous sedimentary 

rocks are well exposed in the vicinity of Las Vegas, 

in western San Miguel County (Northrop, and others, 

1946). These sediments were tested for radioactivity 

at several localities. At Kearny and Romeroville Gaps, 

2 and 5 miles, respectively, southwest of Las Vegas,- 

and at a point 10 miles southeast of Las Vegas, on 

State Route 20, traces of radioactivity are present 

in the Morrison and Purgatoire formations. In the 

Morrison formation several beds as much as 3 feet 

thick show traces of radioactivity. A 3-foot bed of 

shale at Romeroville Gap was selected as representative of this radioactive material in the Morrison 

and was sampled. The sample (no.. 28) contains 

0. 005 percent equivalent uranium and 0. 002 percent 

uranium.

At the three localities the top of the Purgatoire 

formation contains a bed of black shale about 20 feet 

thick. A representative sample (no. 29) taken from 

this shale at Romeroville Gap contains 0. 002 percent 

equivalent uranium and 0.0009 percent uranium. 

Bentonitic rocks in the Graneros shale show traces of 

radioactivity at a locality a quarter of a mile east 

of Las Vegas on State Route 65. Ten beds of bentonite 

ranging from one-eighth inch to nearly 1 foot in thickness occur in a stratigraphic interval of about 50 feet. 

A representative sample (no. 30) collected from one 

of the beds contains 0. 003 percent equivalent uranium 

and 0. 0012 percent uranium.

COLFAX SILL AREA

In eastern Coif ax County an area of about 

100 square miles contains many sills of monzonitic 

and syenitic composition. Most of these sills are 

emplaced in the Graneros and Carlile shales of 

Late Cretaceous age, although a few sills occur 

in Jurassic sedimentary rocks. A rapid survey 

showed that many, perhaps most, of these intrusive rocks contain traces of radioactive materials, 

and one type of porphyry, a distinctive grayishgreen rock having large feldspar phenocrysts, 

appears to be slightly more radioactive than other 

types. A sample (no. 31) of this rock taken in 

sec. 6, T. 27 N., R. 26 E. contains 0.008 percent equivalent uranium and 0.0041 percent uranium. A dike, about 10 feet wide, that leads 

to the overlying sill at a nearby locality cuts the 

Carlile shale, and the shale is conspicuously 

altered for a distance of 5 to 10 feet on both sides 

of the dike. A sample (no. 32) of the altered 

shale contains 0.002 percent equivalent uranium and 

0.0004 percent uranium.
RADIOACTIVITY AND CHEMICAL ANALYSES OP SAMPLES COLLECTED

Sample 

no.

Laboratory 

serial no.

Equivalent 

uranium 

(percent)

Uranium 

(percent)

Description and locality

Samples from the Datil area

1

2

3a 

3b 

4 

5a

5b

5c 

5d

6

7

10

11

12

13

14

15

16

l6a

17

201449

201454

201447

201448

201450

201440

201441

201442

201443

201444

201451

201439

201446

201445

201437

201452

201436

201438

201434

201419

201420

201421

See footnote at end of table.

0.074

.062

.056

.003

.051

.025

.005

.004

.013

.095

.023

.003

.003

.003

.003

.003

.002

.002

0.004

.056

.042 

.0017 

'.022 

.022

.019

.004

.002

.002

1 .036

.011

.017

.026

.0005

.0006 

.0006 

'.0011

.0009

.0007

.0010

A channel sample of a lens of sandstone in the cuesta-forming san

formation at a point where the lens is 1 foot thick. The sands

and twigs. Sec. 10 or 11, T. 2 N., R. 11 W.

A selected sample of the lower 3 inches of a sandstone bed in the 

ber of the Mesaverde formation. The zone contains carbonized l

R. 11 W.

A selected sample of the lower inch of a sandstone bed in the cue

the Mesaverde formation. The sample contains a yellow uranium 

A grab sample of the upper 2 feet of black shale immediately belo

sample J>a was taken.

A water sample from the well at the McEhaul ranch (sec. 14, T. 2 

water from the cuesta-forming sandstone member of the Mesaverde 

A grab sample of the lower 8 inches of a sandstone bed in the cue

of the Mesaverde formation. The sandstone contains shale pellet

R. 10 W.

A selected sample of the lower 2 inches of a sandstone bed in the 

ber of the Mesaverde formation. Sec. 18 or 19, T. 2 N., R. 10 W

Limonite deposited along bedding plane immediately below the bed 

A grab sample of the uppermost foot of black shale immediately be

shale also is immediately below the cuesta-forming sandstone mem

A grab sample of sandstone from the cuesta-forming sandstone memb

The sample contains pieces of carbonized wood. Sec. 21, T. 2 N

A water sample from the well at the Webster ranch (sec. 34, T. 2 

water from the cuesta-forming sandstone member of the Mesaverde 

A grab sample of the lowest 6 inches of a sandst9ne bed in the cue

the Mesaverde formation. Sec. 27, T. 2 N., R! 10 W.

A selected sample of the lowest inch of a sandstone bed in the cu

the Mesaverde formation. The sample includes a thin crust of l

bedding plane beneath the sandstone. A yellow uranium mineral 

Sec. 26(?), T. 2 N., R. 10 W.

A grab sample of the lowest 4 inches of a sandstone bed in the cu

2 N., R. 10 W. 

5(?), T. 5 S., R. 8 W.

the Mesaverde formation. Sec. 26, T. 

A. grab sample of a rhyolite dome. Sec.

A. sample of water from a spring that emerges from rhyolite tuff 

A. grab sample of welded tuff. Sec. 24(?), T. 8 S., R. 12 W. 

A. grab sample of a rhyolite dome* Sec. 3M?)> T - 73., R. 15 W. 

A grab sample of a rhyolite dome.- Sec. 3, T. 5 S., R. .16 W. 

A. grab sample of kaolinized(?) and silicified latite from a turqu

R. 8 E.

A selected sample of turquoise separated from sample 16. 

A grab sample of a medium-grained monzonite from the dump of the 

R. 8 E.
RADIOACTIVITY AND CHEMICAL ANALYSES OF SAMPLES COLLECTED CONTINUED

Sample 

no.

18

19 

20 

21

22

Laboratory 

serial no.

Equivalent 

uranium 

(percent)

Uranium 

(percent)

Description and locality

Samples from Datil area Continued

201424

201425 

201425 

201426

201422

0.009

.007 

.005 

.005

.002

0.0085

.0010 

.0005

.0007

.0004

A grab sample of kaolinized(?) and silicified latite from a turq

R. 8 E. Clay is predominant in this sample. 

A grab sample of kaolinized(?) and silicified latite from the sa

A grab sample of relatively unaltered latite from the same local

A grab sample of kaolinized(?) and silicified latite from the Ev

T. 15 N., R. 8 E. 

A grab sample of slightly altered shale from the Mancos formatio

a monzonitic intrusive. Sec. 8, T. 14 N., R. 8 E.

Samples from the Glorieta district

25

24

201427 

201428

0.002 

.001

0.0004 

.0005

A grab sample of copper ore from a 5-foot bed of arkose in the S

Sec. 14(7), T. 16 N., R. 11 E. 

A grab sample of iron ore from the San Andres formation at the o

T. 15 N., R. 11 E.

oo Samples from the Tecolote district

25 

26 

27

201451 

201450 

201429

0.002 

.005 

.001

0.0005 

.0004 

.0004

A grab sample from an area of green rock in an arkose bed in the 

The locality is one-quarter mile west of the village of Tecolo

A grab sample of copper ore collected from the dump of the old B

R. 15 E. 

A channel sample of a bed of coal 2 feet thick in the Madera lim

R. 15 E.

Samples from the Las Vegas area

28 

29

50

201452 

201455

201454

0.005

.002 

.005

0.0020 

.0009

.0012

A channel sample of a bed of shale 5 feet thick in the Morrison 

Romeroville Gap, 5 miles south of Las Vegas, N. Mex. 

A channel sample of a bed of bony shale, one foot thick, present 

the Purgatoire formation. The locality is Romeroville Gap, 5 m

N. Mex. 

A channel sample of a 10-inch bentonite bed in the Graneros shale

mile east of Las Vegas, N. Mex.

Samples from the Golf ax sill area

51 

52

201455 

201456

0.008 

.002

0.0041 

.0004

A grab sample of a grayish-green sill emplaced in the Carlile sh

A grab sample of altered Carlile shale adjacent to a dike. Sec. 

1 In pans per million.
LITERATURE CITED

Kelley, V. C., 1949, Geology and economics of New

Mexico iron-ore deposits: N. Mex. Univ. Pubs, in

Geology, no. 2, p. 195-197. 

Lasky, S. G., and Wootton, T. P., 1933, The metal

resources of New Mexico and their economic features:

N. Mex. Bur. Mines Bull. 7. 

Lindgren, W., Graton, L. C., and Gordon, C. H.,

1910, The ore deposits of New Mexico: U. S. Geol.

Survey Prof. Paper 68.

Northrop, S. A., Sullwold, H. H., MacAlpin, A. J., and 

Rogers, C. P., 1946, Geologic maps of a part of the Las 

Vegas basin and of the foothills of the Sangre De Cristo 

Mountains, San Miguel and Mora Counties, New Mexico: 

U. S. Geol. Survey Oil and Gas Inv. Prelim. Map 54.

Read, C. B., Wilpolt, R. H., Andrews, D. A., Summerson, 

C. H., and Wood, G. H., 1944, Geologic map and stratigraphic sections of Permian and Pennsylvanian rocks of 

parts of San Miguel, Santa Fe, Sandoval, Bernalillo, 

Torrance, and Valencia Counties, north-central New Mexico: U. S. Geol. Survey Oil and Gas Inv. Prelim. Map 21.,

INT.-OOP. SEC., WASH., D.CTO »3l