Mineral Resources of the

Jornada del Muerto Wilderness Study Area,

Socorro and Sierra Counties, New Mexico

U.S. GEOLOGICAL SURVEY BULLETIN 1734-A

Chapter A

Mineral Resources of the

Jornada del Muerto Wilderness Study Area,

Socorro and Sierra Counties, New Mexico

By DONALD H. RICHTER and RICHARD W. SALTUS 

U.S. Geological Survey

GEORGE S. RYAN 

U.S. Bureau of Mines

U.S. GEOLOGICAL SURVEY BULLETIN 1734

MINERAL RESOURCES OF WILDERNESS STUDY AREAS 

WEST-CENTRAL NEW MEXICO
DEPARTMENT OF THE INTERIOR 

DONALD PAUL MODEL, Secretary

U.S. GEOLOGICAL SURVEY 

Dallas L. Peck, Director

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON: 1987

For sale by

Books and Open-File Reports Section

U.S. Geological Survey

Federal Center

Box 25425

Denver, CO 80225

Library of Congress Cataloging-in-Publication Data

Richter, Donald H.

Mineral resources of the Jornada del Muerto Wilderness Study Area, 

Socorro and Sierra Counties, New Mexico.

(U.S. Geological Survey bulletin ; 1734)(Mineral resources of 

wilderness study areas west-central New Mexico)

Bibliography: p.

Supt. of Docs, no.: I 19.3:1734-A

1. Mines and mineral resources New Mexico Jornada del Muerto 

Wilderness. 2. Jornada del Muerto Wilderness (N.M.). I. Saltus, R. W. 

(Richard W.) II. Ryan, George S. III. Title. IV. Series. V. Series: 

Mineral resources of wilderness study areas west-central New Mexico.

QE75.B9 no. 1734 

[TN24.N6]

557.3 s 

[553'.09789'62]

87-600169
STUDIES RELATED TO WILDERNESS

Bureau of Land Management Wilderness Study Areas

The Federal Land Policy and Management Act (Public Law 94-579, October 21, 

1976) requires the U.S. Geological Survey and the U.S. Bureau of Mines to conduct mineral 

surveys on certain areas to determine the mineral values, if any, that may be present. Results 

must be made available to the public and be submitted to the President and the Congress. 

This report presents the results of a mineral survey of the Jornada del Muerto (NM-020-055) 

Wilderness Study Area, Socorro and Sierra Counties, New Mexico.

CONTENTS

Summary 1 

Introduction 3

Investigations by the U.S. Bureau of Mines 4 

Investigations by the U.S. Geological Survey 4 

Appraisal of identified resources 4 

Assessment of potential for undiscovered resources 4 

Geology 4 

Geophysics 5

Gravity data 5 

Aeromagnetic data 5 

Aerial radiometric survey 5 

Mineral resource potential 9 

Metallic deposits 9 

Geothermal energy 9 

Oil and gas 9 

Coal 9 

Sand 9

Gem-quality olivine (peridot) 9 

References cited 10 

Appendix 11

FIGURES

1. Map showing location of the Jornada del Muerto Wilderness Study Area 1

2. Map showing mineral resource potential and geology of the Jornada del Muerto 

Wilderness Study Area 2

3. Isostatic residual gravity map of the Jornada del Muerto Wilderness Study Area 

and vicinity 6

4. Map showing depth to Paleozoic basement rocks below Santa Fe Group rocks, 

Jornada del Muerto Wilderness Study Area and vicinity 7

5. Aeromagnetic map of the Jornada del Muerto Wilderness Study Area and 

vicinity 8

Contents V

MINERAL RESOURCES OF WILDERNESS STUDY AREAS WEST-CENTRAL NEW MEXICO

Mineral Resources of the

Jornada del Muerto Wilderness Study Area,

Socorro and Sierra Counties, New Mexico

By Donald H. Richter and Richard W. Saltus 

U.S. Geological Survey

George S. Ryan 

U.S. Bureau of Mines

SUMMARY

The Jornada del Muerto Wilderness Study Area 

(NM-020-055) includes 31,147 acres in Socorro and Sierra 

Counties in west-central New Mexico. It lies in remote 

country on the east side of the Rio Crande valley, approximately 35 mi -miles) south of the city of Socorro 

(fig- D.

The wilderness study area includes most of the 

east half of a geologically young (760,000-year-old) basaltic lava field. The vent area for the lavas is marked by 

a cinder cone and lava domes about 1 mi west of the 

wilderness study area boundary. The lava field overlies 

a relatively flat surface of thin, unconsolidated basin and 

eolian sediments, which in turn overlie as much as 

10,000 ft (feet) of older sedimentary rocks that filled the 

tectonically active Rio Crande rift valley during late Tertiary (see geologic time chart in Appendix) time (2-20 

million years ago). Paleozoic limestones, which in southeast New Mexico are highly productive oil and gas reservoir rocks, probably underlie the wilderness study area 

at depth.

There has been no mineral production in the wilderness study area, and no leasable or locatable mineral 

deposits are known. The wilderness study area has low 

mineral resource potential for metals, including sedimentary uranium, geothermal energy, oil and gas, and 

magmatic segregates of gem-quality olivine (peridot); the 

mineral resource potential for coal is unknown (fig. 2). 

The northwest and southwest parts of the study area 

have moderate potential for undiscovered sand resources.

107°30' 107°00' 106°30'

34° 

00'

33° 

00'

' p\ Socorro

\- APPROXIMATE 

' BOUNDARY OF 

THE JORNADA 

DEL MUERTO 

WILDERNESS 

STUDY AREA

WHITE 

SANDS 

MISSILE 

RANGE

Truth or 

Consequences

20 MILES

EXPLANATION 

 Improved dirt road

Figure 1. Map showing location of the Jornada del 

Muerto Wilderness Study Area, New Mexico.

Jornada Del Muerto Wilderness Study Area A1
106°50' 106°45'

33°30'

APPROXIMATE BOUNDARY OF 

THE JORNADA DEL MUERTO 

WILDERNESS STUDY AREA 

(NM-020-055)

COUNTY 

COUNTY

2 MILES

Figure 2 (above and facing page). Map showing mineral resource potential and geology of 

the Jornada del Muerto Wilderness Study Area, New Mexico.

A2 Mineral Resources of Wilderness Study Areas West-Central New Mexico
EXPLANATION OF MINERAL 

RESOURCE POTENTIAL

Geologic terrane having high mineral resource

potential for sand, with certainty level B 

L/B Geologic terrane having low mineral resource potential for metals, including sedimentary uranium, oil and gas, and geothermal energy, with certainty level B 

L/C Geologic terrane having low mineral resource 

potential for gem-quality olivine, with certainty level C

LJ/A Geologic terrane having unknown mineral resource potential for coal, with certainty 

level A

Certainty levels

A Available information is not adequate for determination of the level of mineral resource 

potential

B Available information suggests level of mineral resource potential

C Available information gives a good indication of level of mineral resource potential

CORRELATION OF MAP UNITS

Qbc

Qbyd

Qbod

Qbf

Qea

«

 Holocene

 Pleistocene

h QUATERNARY

DESCRIPTION OF MAP UNITS

Qea Eolian and alluvial deposits, undivided (Holocene and Pleistocene) Chiefly stablized 

and active sheet sand and sand dunes intermixed with fine-grained alluvium in numerous 

small discontinuous drainages. Maximum 

thickness less than 10 ft

Lava of Jornada del Muerto (Pleistocene) Medium-gray to black, porphyritic alkalic basalt 

containing phenocrysts of plagioclase (10-15 

percent) and olivine (2-5 percent) in an intergranular to intersertal groundmass of feldspar, 

mafic minerals, and glass. Locally contains 

xenoliths of quartz and tridymite. Maximum 

thickness about 250 ft

Qbc Cinder cone Scoriaceous lapilli, cinder, and 

blocks. Overlies vent for lava of Jornada del 

Muerto

Qbyd Young lava dome Small, partly collapsed 

lava dome

Qbod Old lava dome Broad lava dome containing 

an extensive collapsed lava tube and many pit 

craters. Dome is partly collapsed peripheral 

to vent area

Qbf Lava flows Massive, extremely vesicular flows 

having a variety of collapse features

 Contact Both known and approximately located

-i ' r-r- Collapse scarp Hachures on collapsed side 

Trace of collapsed lava tube

INTRODUCTION

The Jornada del Muerto Wilderness Study Area 

(NM-020-055) includes 31,147 acres in Socorro and 

Sierra Counties in south-central New Mexico (fig. 1). It 

is about 35 mi south of the city of Socorro and is on 

the east side of the Rio Grande but within the Rio Grande 

rift valley. Access is by several improved dirt roads that 

service remote ranches in the area, and these roads can 

be difficult to traverse during periods of inclement 

weather. The best routes are south from U.S. Highway 

380 just west of San Antonio, N. Mex., a distance of 

about 25 mi, and north from Truth or Consequences, N. 

Mex., a distance of about 48 mi. The wilderness study 

area includes most of the east half of a large Pleistocene 

lava field, roughly 15 mi in diameter; the lava flowed 

out on a relatively flat alluvial plain from a central vent 

area. The lava field has the form of a very broad shield 

with the central vent area about 250 ft higher than the 

distal edges of the flows. The surface of the field is extremely rough and consists largely of broken and disrupted 

lava, collapse pits, rifts, and pressure domes; no streams 

drain the lava field.

This report presents an evaluation of the mineral 

endowment (identified resources and mineral resource potential) of the study area and is the product of several 

separate studies by the U.S. Bureau of Mines and the 

U.S. Geological Survey. Identified resources are classified 

according to the system of the U.S. Bureau of Mines and 

U.S. Geological Survey (1980), which is shown in the 

Appendix of this report. Identified resources are studied 

by the Bureau of Mines. Mineral resource potential is the 

likelihood of occurrence of undiscovered metals and nonmetals, industrial rocks and minerals, and of undiscovered

Jornada Del Muerto Wilderness Study Area A3
energy sources (coal, oil, gas, oil shale, and geothermal 

sources). It is classified according to the system of 

Goudarzi (1984) and is shown in the Appendix. Undiscovered resources are studied by the U.S. Geological 

Survey.

Investigations by the U.S. Bureau of Mines

The Bureau of Mines investigation included a search 

of literature relating to the mineral resources and mining 

activity in or near the study area. Claim status was 

checked in the U.S. Bureau of Land Management claimrecordation files, and it was determined that no claims 

exist within the study area.

Bureau of Mines personnel spent 10 employee-days 

in the study area. During the field investigation, five rock 

and soil samples were collected (Ryan, 1986). All samples were analyzed for gold and silver by fire assay and 

for 40 elements by semiquantitative optical-emission spectrographic methods at the Bureau of Mines Reno Research 

Center, Reno, Nev. Detailed information is available 

through the Intermountain Field Operations Center, Building 20, Denver Federal Center, Denver, Colorado 80225.

Investigations by the U.S. Geological Survey

A brief field investigation consisted of helicoptersupported geologic mapping and rock sampling. The absence of streams or any locally derived alluvial material 

in the wilderness study area ruled out the possibility of 

a stream-sediment geochemical investigation. Small-scale 

gravity and aeromagnetic maps of the wilderness study 

area and vicinity were prepared from gravity data used 

for regional gravity maps of New Mexico and a widely 

spaced aeromagnetic survey flown for the National Uranium Resource Evaluation program. No new geophysical 

data were acquired for this resource evaluation.

Acknowledgments. Personnel of the Bureau of 

Land Management in Socorro, N. Mex., especially 

geologist Roy Dean, were extremely helpful in providing 

information on the wilderness study area and making 

available to us the Bureau of Land Management's aerial 

photographs. Special thanks are also due to G.R. Osburn 

of the New Mexico Bureau of Mines and Mineral Resources in Socorro for providing data on the Jornada del 

Muerto lava field. A report on the geology, energy, and 

mineral resources of the Armendaris area, New Mexico 

(Krason, Jan, Wodzicki, Antoni, and Cruver, S.K., 

unpub. data, 1982), prepared for the Bureau of Land 

Management, was a useful guide in the preparation of 

this report.

APPRAISAL OF IDENTIFIED RESOURCES

By George S. Ryan 

U.S. Bureau of Mines

The Jornada del Muerto Wilderness Study Area 

does not contain any identified mineral resources. No 

known locatable or leasable mineral deposits are in the 

wilderness study area or within 2-5 mi of the study area, 

and the wilderness study area does not contain any existing mining claims. The lava flow of Jornada del Muerto 

constitutes a possible source of construction or decorative 

stone, but the area is so distant from any potential market 

that stone is not considered a resource.

ASSESSMENT OF POTENTIAL FOR 

UNDISCOVERED RESOURCES

By Donald H. Richter and Richard W. Saltus 

U.S. Geological Survey

Geology

The Jornada del Muerto Wilderness Study Area consists of the east half of an extensive Pleistocene lava field, 

dated at 760,000 years (Bachman and Mehnert, 1978), 

in the Rio Grande valley of west-central New Mexico. 

The lava field forms a low broad shield about 15 mi in 

diameter and has a maximum thickness of about 250 ft. 

The vent area for the lava is 1 mi west of the wilderness 

study area boundary and consists of a young cinder cone 

constructed on a partly collapsed small lava dome, which 

in turn is superimposed on an older and considerably 

larger lava dome (fig. 2). A large, partly collapsed lava 

tube extends more than a mile through the older lava 

dome.

The lavas are porphyritic alkali olivine basalts containing phenocrysts of plagioclase (10-15 percent) and olivine (3-5 percent) in a fine-grained groundmass of feldspar, mafic minerals, and, locally, glass. Xenoliths of 

quartz, partly replaced by tridymite, as much as 4 inches 

in diameter, are locally abundant in some parts of the 

flow. Chemically, the lavas contain about 50 percent SiO2 

and 5 percent Na2O+K2O, and probably represent mantlederived magma that ascended to the surface with minimum contamination by crustal rocks. The lavas are typical 

of the many lava fields that have been erupted throughout 

the length of the Rio Grande rift system in the last 6 

million years.

The lavas were erupted onto a relatively flat surface 

of Quaternary basin sediments, piedmont alluvium, and 

eolian deposits probably less than 200 ft thick. These thin

A4 Mineral Resources of Wilderness Study Areas West-Central New Mexico
alluvial and eolian deposits overlie and in part are gradational downward into a great thickness of sedimentary 

rocks of the Santa Fe Group that filled the tectonically 

active Rio Grande rift during early Quaternary and late 

Tertiary time. The Santa Fe Group consists of moderately 

indurated conglomerate, sandstone, and siltstone and may 

be as much as 3,500 ft thick under the wilderness study 

area. Locally, the rocks are tuffaceous and intercalated 

with mafic lava flows. The Santa Fe Group was deposited 

unconformably on rocks ranging from Precambrian to 

early Tertiary in age. Pre-Santa Fe Group basement rocks 

are exposed at Little San Pascual Mountain, about 5 mi 

north of the wilderness study area, where upper Paleozoic 

sedimentary rocks, including Pennsylvanian and Permian 

limestones, dip to the southeast under basin-fill deposits 

of the Santa Fe Group (Geddes, 1963). The lava field 

is locally covered by a veneer of eolian deposits.

Geophysics

Gravity Data

A regional isostatic residual gravity map (fig. 3) 

of a 30-minute by 30-minute (27.5x35 mi) area containing the wilderness study area was compiled using data 

from about 600 gravity stations; none of these stations 

are in the wilderness study area. The data for the map 

were assembled and edited for regional gravity maps of 

New Mexico by Cordell and others (1982). The map (fig. 

3) shows the gravity effect of density distributions in the 

upper crust (Simpson and others, 1986).

The wilderness study area is on an elongate northtrending gravity high. This high is flanked on the west 

by steep gravity gradients leading down into the Rio 

Grande rift zone. On the east side of the high, the gravity 

field drops to a very large closed gravity low (40 milligals 

below the high) centered near the Baber well about 16 

mi northeast of the wilderness study area.

The regional anomalies on the gravity map are probably due primarily to the relief on the contact between 

the relatively low density Santa Fe Group sedimentary 

rocks at the surface and the underlying high density Paleozoic carbonate rocks. Thus, the central gravity ridge indicates rather thin Santa Fe Group rocks, a shallow depth 

to the Paleozoic rocks, and the large closed low to the 

east is caused by a relatively thick Santa Fe section. If 

the Paleozoic limestones are assumed to have a bulk density of 2.7 g/cm3 (grams per cubic centimeter), the largest 

reasonable density contrast between the Paleozoic rocks 

and the Santa Fe Group rocks is probably 0.5 g/cm3 . If 

this maximum density contrast is assumed, the minimum 

depth to the Paleozoic basement can be modeled. Using 

the method of Cordell and Henderson (1968), a map

showing minimum depth to Paleozoic basement rocks has 

been prepared (fig. 4). Because no gravity stations are 

within the wilderness study area boundary, the depth estimate there is based on data from outside of the area. 

The map shows that the Paleozoic basement may be within 3,500 ft of the surface near the wilderness study area 

and drops to at least 10,000 ft under the gravity low near 

Baber well to the east.

The steep gradient along the western edge of the 

gravity ridge (fig. 3), best defined by a line of closely 

spaced gravity stations at the north edge of the ridge, 

is probably associated with graben faulting along the Rio 

Grande rift to the west.

Aeromagnetic Data

Data for an aeromagnetic map (fig. 5) were obtained as part of the National Uranium Resource Evaluation (NURE) program in 1982 (Berry and others, 1982). 

The survey was flown at an altitude of 400 ft above the 

ground along flight lines 3 mi apart. Because the flight 

lines are so widely spaced, short-wavelength features cannot be contoured reliably from line to line. In order to 

avoid false correlation of these contours by computer contouring, a grid was produced from the original data using 

the method of minimum curvature (Briggs, 1974), and 

the grid was continued upward 1,600 ft to remove the 

short-wavelength features.

The aeromagnetic map (fig. 4) is dominated by a 

large crescent-shaped closed low northeast of the study 

area with a triangular-shaped high intersecting it from the 

west. These broad long-wavelength features are probably 

due to relief on the contact between the Precambrian basement rocks and the relatively nonmagnetic rocks above 

them. A two-dimensional structural model constructed 

from two flight lines crossing the broad low indicated a 

depth of about 23,000 ft to the Precambrian basement 

under the lowest part of the anomaly at the eastern edge 

of the wilderness study area. This model assumed a 

0.001-electromagnetic unit per cubic centimeter intensity 

of magnetization for normally polarized basement rocks. 

The same model yielded depths of about 7,000 ft to Precambrian basement under the magnetic highs flanking the 

western and southern edges of the wilderness study area.

A small ridge of aeromagnetic lows coincides with 

the gravity high discussed in the previous section. This 

aeromagnetic anomaly probably reflects a small increase 

in the depth of the Paleozoic basement (fig. 4); this increase suggests the presence of a small arch in the basement rock.

Aerial Radiometric Survey

The Jornada del Muerto Wilderness Study Area has 

low overall radioactivity. The aerial radiometric survey

Jornada Del Muerto Wilderness Study Area A5
107°00' 106°30'

33°45'

33°30'

Figure 3. Isostatic residual gravity map of the Jornada del Muerto Wilderness Study Area and vicinity, New Mexico. 

Contour interval 2 milligals. Dots are gravity stations. Reduction density 2.67 grams per cubic centimeter. Hachures 

show areas of lower gravity values. Data are from Cordell and others (1982). Wilderness study area is shaded.

A6 Mineral Resources of Wilderness Study Areas West-Central New Mexico
106°52'30" 106°37'30"

33°45'

33°30' 

Figure 4. Map showing depth to Paleozoic basement rocks below Santa Fe Group rocks, Jornada del Muerto Wilderness Study Area and vicinity, New Mexico. Contour interval 0.2 kilometers (about 650 ft). Wilderness study area is 

shaded.

Jornada Del Muerto Wilderness Study Area A7
107°00' 106°30'

33°45'

33°30'

Figure 5. Aeromagnetic map of the Jornada del Muerto Wilderness Study Area and vicinity, New Mexico. Dashed 

lines are flight lines from the National Uranium Resource Evaluation survey. Contour interval 10 gammas. Wilderness 

study area is shaded.

A8 Mineral Resources of Wilderness Study Areas West-Central New Mexico
indicated values of 1.6-2.0 ppm (parts per million) equivalent uranium, 6.0-7.5 ppm equivalent thorium, and 1.5- 

2.1 percent potassium (J.S. Duval, U.S. Geological Survey, written commun., 1986). No anomalies are within 

or near the study area.

Mineral Resource Potential

Metallic Deposits

The Jornada del Muerto Wilderness Study Area 

lacks the geologic environments favorable for metallic 

mineral deposits, with the exception of sedimentary uranium. Occurrences of uranium minerals have been found 

in sedimentary rocks of the Tertiary Santa Fe Group 

throughout New Mexico (Hilpert, 1965). These moderately indurated and generally permeable basin-fill sediments contain abundant silicic volcanic debris and some 

organic-rich material, features which suggest a favorable 

environment for sandstone-hosted uranium deposits. In addition, the wilderness study area subsurface may meet 

some of the criteria proposed by Carlisle and others 

(1978) for uranium-bearing nonpedogenic calcrete deposits, namely adequate source terrane (deeply eroded 

Tertiary volcanic rocks) and a large catchment area. On 

the other hand, Berry and others (1982) concluded that 

the Santa Fe Group (in the Tularosa I°x2° quadrangle, 

New Mexico) is unfavorable for either uraniferous calcrete 

or sandstone uranium deposits because the unit is above 

ground-water table and is highly oxidized. A low potential 

for metals, including uranium in sedimentary-type deposits, is assigned to the wilderness study area, with certainty level B.

Geothermal Energy

Two thermal springs, with water temperatures of 

24 °C and 34 °C, 5-7 mi southwest of the wilderness 

study area, and the presence of Pleistocene volcanic activity suggest that an anomalous heat source may underlie 

the general area. Geophysical data, however, do not indicate the presence of any plutonic bodies close to the surface of the study area. The wilderness study area is assessed as having a low potential, at certainty level B, for 

geothermal energy.

Oil and Gas

The wilderness study area is probably underlain at 

depths as shallow as 3,000 ft by upper Paleozoic rocks 

that in southeastern New Mexico are highly productive 

reservoir rocks. In the Rio Grande rift valley, however,

these rocks have been structurally disturbed and intruded 

by igneous rocks, factors which do not enhance the rock's 

ability to hold significant quantities of oil and gas. Five 

exploratory holes testing the oil and gas potential of the 

Paleozoic rocks have been drilled near the wilderness 

study area, two about 6 mi to the southwest and three 

about 14 mi to the north; all were dry (U.S. Geological 

Survey, 1981). The wilderness study area is assessed as 

having a low potential, at certainty level B, for oil and 

gas.

Coal

The wilderness study area consists of recent volcanic rocks and therefore lacks the environment suitable for 

coal. Coal is present 25 mi north of the study area in 

rocks of the Mesaverde Group at the Carthage coal field. 

Because of the cover of Quaternary deposits, it is unknown how far south the Mesaverde Group extends, and 

whether coal-bearing units in the Mesaverde are present 

beneath the study area. Most of the coal in New Mexico 

occurs in the Mesaverde Group. However, minor amounts 

of coal occur in southern New Mexico in Paleozoic sedimentary rocks (U.S. Geological Survey, 1965). Paleozoic 

sedimentary rocks may underlie the wilderness study area 

at depths as shallow as 3,000 ft below the surface but 

whether they are coal-bearing is unknown. The mineral 

resource potential for coal in the wilderness study area 

is unknown, with certainty level A.

Sand

In the northwestern and southwestern parts of the 

study area, deposits of sand as much as 10 ft thick overlie 

the basalt. The mineral resource potential for undiscovered 

sand resources in these areas is moderate, with certainty 

level B.

Gem-Quality Olivine (Peridot)

Semiprecious gem-quality olivine occurs in several 

late Tertiary-Quaternary alkali olivine basalt flows in the 

southwestern United States. The olivine occurs both as 

phenocrysts disseminated throughout the lava and as 

xenocrystic clots carried up from depth by the lava. Most 

of the occurrences are only mineralogic curiosities; however, in the San Carlos Indian Reservation in southeastern 

Arizona gem olivine is mined from a young basalt flow 

(Vuich and Moore, 1977). The lavas of Jornada del 

Muerto contain only 3-5 percent small phenocrysts of olivine, and no olivine-bearing xenocrystic nodules have 

been observed; the potential for gem-quality olivine is 

low, with certainty level C.

Jornada Del Muerto Wilderness Study Area A9
REFERENCES CITED

Bachman, G.O., and Mehnert, H.H., 1978, New K-Ar dates 

and the late Pliocene to Holocene geomorphic history of 

the central Rio Grande region, New Mexico: Geological Society of America Bulletin, v. 89, p. 283-292.

Berry, V.P., Nagy, P.A., Spreng, W.C., Barnes, C.W., and 

Smouse, De Forrest, 1981, Tularosa quadrangle, New 

Mexico [National Uranium Resource Evaluation]: U.S. Department of Energy Report GJQ-014(82), 22 p.

Briggs, I.C., 1974, Machine contouring using minimum curvature: Geophysics, v. 39, no. 1, p. 39-48.

Carlisle, Donald, Merifield, P.M., Orme, A.R., Kohl, M.S., 

Kolker, Oded, and Lunt, O.R., 1978, The distribution of 

calcretes and gypcretes in southwestern United States and 

their uranium favorability based on a study of deposits in 

western Australia and southwest Africa (Namibia): U.S. Department of Energy Open-File Report GJBX-29(78), 

274 p.

Cordell, Lindrith, and Henderson, R.G., 1968, Iterative threedimensional solution of gravity anomaly data using a digital 

computer: Geophysics, v. 33, no. 4, p. 596-601.

Cordell, Lindrith, Keller, G.R., and Hildenbrand, T.G., 1982, 

Bouguer gravity map of the Rio Grande Rift, Colorado, 

New Mexico, and Texas: U.S. Geological Survey Geophysical Investigations Map GP-949, scale 1:1,000,000.

Geddes, R.W., 1963, Structural geology of Little San Pasqual 

Mountain and the adjacent Rio Grande Trough: New Mexico 

Institute of Mining and Technology, Socorro, M.S. thesis, 

62 p.

Goudarzi, G.H., compiler, 1984, Guide to preparation of mineral survey reports on public lands: U.S. Geological Survey 

Open-File Report 84-787, 42 p.

Hilpert, L.S., 1965, Uranium, in Mineral and water resources 

of New Mexico: U.S. 89th Congress, 1st Session, Senate 

Committee on Interior and Insular Affairs, Committee Print, 

p. 209-226; New Mexico Bureau of Mines and Mineral Resources Bulletin 87, 437 p.

Ryan, G.S., 1986, Mineral investigation of the Jornada del 

Muerto Wilderness Study Area (NM-020-055), Sierra and 

Socorro Counties, New Mexico: U.S. Bureau of Mines 

Open File Report MLA-21-86, 125 p.

Simpson, R.W., Jachens, R.C., Blakely, R.J., and Saltus, 

R.W., 1986, A new isostatic residual gravity map for the 

conterminous United States with a discussion on the significance of isostatic anomalies: Journal of Geophysical Research, v. 91, no. B8, p. 8348-8372.

U.S. Bureau of Mines and U.S. Geological Survey, 1980, Principles of a resource/reserve classification for minerals: U.S. 

Geological Survey Circular 831, 5 p.

U.S. Geological Survey, 1965, Mineral and water resources of 

New Mexico: U.S. 89th Congress, 1st session, Senate Committee on Interior and Insular Affairs, Committee Print, 

437 p.

U.S. Geological Survey, 1981, Energy resources of New 

Mexico: U.S. Geological Survey Miscellaneous Investigations Series Map 1-1327, scale 1:500,000.

Vuich, J.S., and Moore, R.T., 1977, Bureau studies olivine 

resources on San Carlos Apache Reservation: Arizona Bureau of Mines Field Notes, v. 7, no. 2, p. 1, 6-10.

A10 Mineral Resources of Wilderness Study Areas West-Central New Mexico
APPENDIX
DEFINITION OF LEVELS OF MINERAL RESOURCE POTENTIAL 

AND CERTAINTY OF ASSESSMENT

Definitions of Mineral Resource Potential

LOW mineral resource potential is assigned to areas where geologic, geochemical, and geophysical characteristics define a geologic environment in which the existence of resources is unlikely. This broad 

category embraces areas with dispersed but insignificantly mineralized rock as well as areas with few 

or no indications of having been mineralized.

MODERATE mineral resource potential is assigned to areas where geologic, geochemical, and geophysical 

characteristics indicate a geologic environment favorable for resource occurrence, where interpretations 

of data indicate a reasonable likelihood of resource accumulation, and (or) where an application of 

mineral-deposit models indicates favorable ground for the specified type(s) of deposits.

HIGH mineral resource potential is assigned to areas where geologic, geochemical, and geophysical characteristics indicate a geologic environment favorable for resource occurrence, where interpretations of 

data indicate a high degree of likelihood for resource accumulation, where data support mineral-deposit 

models indicating presence of resources, and where evidence indicates that mineral concentration has 

taken place. Assignment of high resource potential to an area requires some positive knowledge that 

mineral-forming processes have been active in at least part of the area.

UNKNOWN mineral resource potential is assigned to areas where information is inadequate to assign low, 

moderate, or high levels of resource potential.

NO mineral resource potential is a category reserved for a specific type of resource in a well-defined 

area.

Levels of Certainty

U/A

UNKNOWN

POTENTIAL

H/B

HIGH POTENTIAL

M/B 

MODERATE POTENTIAL

L/B

LOW

POTENTIAL

H/C

HIGH POTENTIAL

M/C 

MODERATE POTENTIAL

L/C

LOW

POTENTIAL

H/D

HIGH POTENTIAL

M/D 

MODERATE POTENTIAL

L/D

LOW POTENTIAL

N/D

NO POTENTIAL

t

CJ 

QC

B C 

LEVEL OF CERTAINTY

A. Available information is not adequate for determination of the level of mineral resource potential.

B. Available information suggests the level of mineral resource potential.

C. Available information gives a good indication of the level of mineral resource potential.

D. Available information clearly defines the level of mineral resource potential.

Abstracted with minor modifications from:

Taylor, R. B., and Steven, T. A., 1983, Definition of mineral resource potential: Economic Geology,

v. 78, no. 6, p. 1268-1270. 

Taylor, R. B., Stoneman, R. ]., and Marsh, S. P., 1984, An assessment of the mineral resource potential

of the San Isabel National Forest, south-central Colorado: U.S. Geological Survey Bulletin 1638, p.

40-42. 

Goudarzi, G. H., compiler, 1984, Guide to preparation of mineral survey reports on public lands: U.S.

Geological Survey Open-File Report 84-0787, p. 7, 8.
RESOURCE/RESERVE CLASSIFICATION

ECONOMIC

MARGINALLY 

ECONOMIC

SUBECONOMIC

IDENTIFIED RESOURCES

Demonstrated

Measured Indicated

1

Reserves 

1

1

Marginal Reserves

Demonstrated 

Subeconomic Resources

Inferred

Inferred Reserves

Inferred 

Marginal Reserves

Inferred 

Subeconomic 

Resources

UNDISCOVERED RESOURCES

Probability Range

 (or) 

Hypothetical i Speculative

1 

1

1 

_L1

Major elements of mineral resource classification, excluding reserve base and inferred reserve base. Modified from 

U. S. Bureau of Mines and U. S. Geological Survey, 1980, Principles of a resource/reserve classification for 

minerals: U. S. Geological Survey Circular 831, p. 5.
GEOLOGIC TIME CHART 

Terms and boundary ages used in this report

EON

Phanerozoic

Proterozoic

Archean 

pre-Arc

ERA

Cenozoic

Mesozoic

Paleozoic

Late Proterozoic

Middle Proterozoic

Early Proterozoic

Late Archean

Middle Archean

Early Archean 

:hean 2

PERIOD

Quaternary

Tertiary

Neogene 

Subperiod

Paleogene 

Subperiod

Cretaceous

Jurassic

Triassic

Permian

Carboniferous 

Periods

Pennsylvanian

Mississippian

Devonian

Silurian

Ordovician

Cambrian

 3800? -

EPOCH

Holocene

Pleistocene

Pliocene

Miocene

Oligocene

Eocene

Paleocene

Late 

Early

Late 

Middle 

Early

Late 

Middle 

Early

Late 

Early

Late 

Middle 

Early

Late 

Early

Late 

Middle 

Early

Late 

Middle 

Early

Late 

Middle 

Early

Late 

Middle 

Early

 -

BOUNDARY AGE 

IN 

MILLION YEARS

- 0.010

- 1.7

- 5

OQ

- 55

_ cc

- 96

-/v 240

- 290 

-~ 330

OCA

- 410

- 500 

- ~ 570 1

- 900 

- 1600

- 2500

- 3000 

- 3400

4550

1 Rocks older than 570 m.y. also called Precambrian, a time term without specific rank.

2 Informal time term without specific rank.

U.S. GOVERNMENT PRINTING OFFICE: 1987 773-047/46,055 REGION NO. 8

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