Mineral Resources of the 

South Pah roc Range 

Wi Iderness Study Area, 

Lincoln County, Nevada

U.S. GEOLOGICAL SURVEY BULLETIN 1 729-A

Chapter A

Mineral Resources of the 

South Pah roc Range 

Wilderness Study Area, 

Lincoln County, Nevada

By BARRY C. MORING, H. RICHARD BLANK, JR., and 

HARLAN N. BARTON 

U.S. Geological Survey

TERRY R. NEUMANN 

U.S. Bureau of Mines

U.S. GEOLOGICAL SURVEY BULLETIN 1729

MINERAL RESOURCES OF WILDERNESS STUDY AREAS: 

SOUTHEASTERN NEVADA
DEPARTMENT OF THE INTERIOR 

DONALD PAUL MODEL, Secretary

U.S. GEOLOGICAL SURVEY 

Dallas L. Peck, Director

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1988

For sale by the

Books and Open-File Reports Section

U.S. Geological Survey

Federal Center, Box 25425

Denver, CO 80225

Library of Congress Cataloging-in-Publication Data

Mineral resources of the South Pahroc Range Wilderness 

Study Area, Lincoln County, Nevada.

(U.S. Geological Survey bulletin ; 1729-A) (Mineral 

resources of wilderness study areas southeastern Nevada : )

Bibliography: p.

Supt. of Docs. no. : I 19.3:1729-A

1. Mines and mineral resources Nevada South Pahroc 

Range Wilderness. 2. South Pahroc Range Wilderness (Nev.) 

1. Moring, Barry C. II. Series: III. Series: Mineral resources 

of wilderness study areas southeastern Nevada ; 

QE75.B9 no. 1729-A 557.3 s [553'.09793'14l 88-600036 

[TN24.N3]
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 part of the South Pahroc 

Range Wilderness Study Area (NV-050-132), Lincoln County, Nevada.

CONTENTS

Summary Al

Abstract 1

Character and setting 1

Identified resources 1

Mineral resource potential 1 

Introduction 3

Character and setting 3

Procedures and sources of data 3

Acknowledgments 3 

Appraisal of identified resources 3

History and production 3

Mines, prospects, mining claims, and mineralized zones 5

Identified resources 5 

Assessment of mineral resource potential 5

Geology 5

Geochemistry 5

Geophysics 6

Mineral and energy resource potential 6 

References cited 7 

Appendixes

Definition of levels of mineral resource potential and certainty of assessment 10

Resource/reserve classification 11

Geologic time chart 12

FIGURES

1. Index map showing location of South Pahroc Range Wilderness Study Area, 

Nevada A2

2. Map showing mineral resource potential of South Pahroc Range Wilderness 

Study Area, Nevada 4

TABLE

1. Mine, claims, and mineralized zones adjacent to the South Pahroc Range 

Wilderness Study Area, Nevada A8

Contents V

MINERAL RESOURCES OF WILDERNESS STUDY AREAS: 

SOUTHEASTERN NEVADA

Mineral Resources of the 

South Pahroc Range 

Wilderness Study Area, 

Lincoln County, Nevada

By Barry C. Moring, H. Richard Blank, Jr., anc/Harlan N. Barton 

U.S. Geological Survey

Terry R. Neumann 

U.S. Bureau of Mines

SUMMARY 

Abstract

At the request of the U.S. Bureau of Land Management, 

approximately 28,395 acres of the South Pahroc Range Wilderness Study Area (NV-050-132) were evaluated for mineral resources (known) and mineral resource potential (undiscovered). 

The U.S. Geological Survey and the U.S. Bureau of Mines 

studied the area, located in southeastern Nevada nearCaliente, 

between 1983 and 1985. In this report, any references to the 

"South Pahroc Range Wilderness Study Area," the "wilderness 

study area," or the "study area" refer only to that part of the study 

area for which the U.S. Bureau of Land Management requested 

mineral surveys. Five perlite placer claim groups lie near the 

study area. Threeof these, including the underground workings 

of one, lie partly within the study area. That part of the study area 

contains an identified, subeconomic perlite resource of about 6 

million tons. Apache tears, of interest to rock collectors, are 

common to slopes underlain by perlite. Ceochemical analyses 

of jasperoid samples revealed that one part of the study area 

contains anomalous concentrations of gold, arsenic, and antimony and has a moderate mineral resource potential for disseminated gold. There is a low resource potential foroil and gas 

and no potential for geothermal energy resources in the study 

area.

Character and Setting

The study area, wholly within the South Pahroc Range, is 

located in southeastern Nevada about 30 mi west of Caliente 

(fig. 1). Basin and Range topography characterizes the region. 

The South Pahroc Range is characterized by a striking 2,000- 

ft-high east escarpment and a rugged, bouldery dip-slope

surface topography. Elevation in the study area ranges from 

4,500 ft in the south to nearly 8,000 ft at the range crest. More 

than 95 percent of the study area consists of volcanic and 

sedimentary rocks of Tertiary age (see appendix for geologic 

time chart). The remainder is Paleozoic quartzite and carbonate rock and Quaternary alluvium.

Identified Resources

No surface mining activity has occurred within the study 

area. However, the underground workings of the Mackie 

perlite mine extend beneath the northeast boundary (fig. 2). In 

the same vicinity, five placer claim groups are adjacent to or 

partly within the study area. Identified resources in the study 

area consist of an indicated resource of approximately 6 

million tons of perlite. This deposit is classified as an identified 

subeconomic resource (see appendixes for resource/reserve 

classification).

Mineral Resource Potential

Fifty-nine stream-sediment samples, 59 heavy-mineralconcentrate samples, and 12 rock samples were collected from 

volcanic and volcaniclastic rocks in the study area for 

semiquantitative geochemical analysis (Barton and Day, 

1984). The data obtained revealed no significant geochemical 

anomalies in the study area. Hydrothermal alteration of limestone and shale located along the southeastern border has 

formed jasperoid deposits. Fifteen samples of these jasperoids 

were collected for quantitative geochemical analysis for elements associated with disseminated gold deposits. One sample 

contains 3 parts per million (ppm) gold (Neumann, 1986) and

Mineral Resources of the South Pahroc Range Wilderness Study Area, Lincoln County, Nevada A1
two others contain anomalous concentrations of arsenic and 

antimony (F.E. Lichte, U.S. Geological Survey, written commun., 1986). These results indicate that this limestone and 

shale outcrop has a moderate resource potential for gold.

Apache tears are common on slopes underlain by perlite. The 

entire study areas has low resource potential for oil and gas 

(Sandberg, 1983). There is no potential for geothermal energy 

resources in the study area.

115" 00' 114° 00'

V

APPROXIMATE BOUNDARY 

OF 

SOUTH PAHROC RANGE 

/ILDERNESS STUDY AREA

(NV-050-132)

Viola 

mining district

Delamar 

mining district

Figure 1. Index map showing location of South Pahroc Range Wilderness Study Area, Nevada.

A2 Mineral Resources of Wilderness Study Areas Southeastern Nevada
INTRODUCTION

This mineral survey was requested by the U.S. Bureau of 

Land Management and is the result of a cooperative effort by 

the U.S. Geological Survey and the U.S. Bureau of Mines. An 

introduction to the wilderness review process, mineral survey 

methods, and agency responsibilities were provided by 

Beikman and others (1983). The U.S. Bureau of Mines 

evaluates identified (known) resources at individual mines 

and known mineralized areas by collecting data on current and 

past mining activities and through field examination of mines, 

prospects, claims, and mineralized areas. Identified resources 

are classified according to the system described by U.S. 

Bureau of Mines and U.S. Geological Survey (1980). Studies 

by the U.S. Geological Survey are designed to provide a 

reasonable scientific basis for assessing the mineral resource 

potential (undiscovered) by determining geologic units and 

structures, possible environments of mineral deposition, presence of geochemical and geophysical anomalies, and applicable ore-deposit models. Mineral assessment methodology 

and terminology as they apply to these surveys were discussed 

by Goudarzi (1984). See appendixes for the definition of 

levels of mineral resource potential and certainty of assessment and for the resource/reserve classification.

Character and Setting

The South Pahroc Range Wilderness Study Area (NV050-132) encompasses 28,395 acres and is located approximately 30 mi west of Caliente, Ne v. (fig. 1), at the center of the 

Caliente 1° by 2° quadrangle. Access to the study area is 

provided by gravel and dirt roads from U.S. Highway 93 at 

Pahroc Summit Pass, Six Mile Rat, and near Alamo (figs. 1, 

2). The elevation of the study area ranges from 4,500 ft at the 

southern end to 7,950 ft at the range crest. The range is a 

typical up-thrown block of the Basin and Range physiographic province. The oldestrocks exposed in the area, Paleozoic 

carbonate rocks and shale of the Pogonip(?) Group and the 

Eureka Quartzite, form small outcrops along the Pahroc fault. 

The rest of the area is composed of Oligocene and Miocene 

volcanic flows, tuffs, and sedimentary rocks. Faulting and 

erosion along the Pahroc fault has resulted in the formation of 

a magnificent east-facing escarpment rising more than 2,000 

ft above the valley floor. The west slope of the range is 

underlain by a biotite-rich welded tuff, the Hiko Tuff. 

Spheroidal weathering of this tuff has resulted in a pronounced bouldery topography where access is difficult. At 

lower elevations, the study area is a desert brushland; at higher 

elevations the brush gives way to scattered stands of pinon 

pine, juniper, and white fir.

Procedures and Sources of Data

The U.S. Geological Survey carried out field investigations intermittently between June of 1983 and March of 1985.

The work included geochemical sampling and analysis (F.E. 

Lichte, written commun., 1986; S.A. Wilson, written commun., 1987; and P.J. Aruscavage, written commun., 1987), 

geologic mapping (Moring, 1987), and interpretation of aeromagnetic, gravity, and aerial gamma-ray data. Previous general geologic studies of the South Pahroc Range and vicinity 

include those of Tschanz and Pampeyan (1970) and Ekren and 

others (1977). Two reports prepared for the U.S. Bureau of 

Land Management discuss geology, energy, and minerals 

(Great Basin GEM Joint Venture, 1983) and reconnaissance 

geochemistry (Barton and Day, 1984).

The U.S. Bureau of Mines conducted an investigation of 

all mines, prospects, and claims and conducted field studies in 

the fall of 1984 and spring of 1985 (Neumann, 1986). Federal 

and Lincoln County mining claim records were reviewed 

prior to field work.

Acknowledgm ents

The authors would like to thank Arel B. McMahan, 

Edward L. McHugh, Harry W. Campbell, David A. Brink 

(U.S. Bureau of Mines) and Raymond L. Elliott (U.S. Geological Survey) for assistance in the office and the field. The 

personnel of the U.S. Bureau of Land Management district 

office in Caliente, Nev., are thanked for making their file on 

the study area available. Dr. Joseph Wilkin of Panaca, Nev., 

owner of the Mackie mine, is thanked for his cooperation.

APPRAISAL OF IDENTIFIED RESOURCES

By Terry R. Neumann 

U.S. Bureau of Mines

History and Production

Although there has been no mining within the South 

Pahroc Range Wilderness Study Area, mining has occurred 

adjacent to the study area's northeast boundary at the Mackie 

perlite mine (fig. 2). The Mackie mine (also known as 

Paramount, Delamar, and Kopenite) has been operating intermittently on a small scale since the late 1940's. The property 

lies on the Barbara claims, one of five placer claim groups 

staked during the late 1940's on a perlite layer that lies within 

the Tertiary rhyolite exposed along the base of the South 

Pahroc Range. Since 1955, the Mackie mine has produced 

about 108,000 tons of high-expansion perlite. Ore from the 

deposit continues to maintain a small foothold in the perlite 

market due to its exceptional expansion properties.

The nearest mining district, the Delamar (Ferguson) district (fig. 1), is 15 mi to the southeast across Delamar Valley. 

Gold and silver deposits were discovered in the Delamar 

Mountains in 1891 and were mined intermittently through 

1950. Most activity took place during the years 1894-1909. 

The Delamar district mines produced ore worth about $15

Mineral Resources of the South Pahroc Range Wilderness Study Area, Lincoln County, Nevada A3
37° 30'

37° 

22' 30"

115° 00'

Pahroc Summit Pass

EXPLANATION

Area with moderate mineral resource potential, certainty 

level C

Area with low mineral resource potential, certainty level C

See appendix for definition of levels of mineral resource potential (M,L) and 

certainty of assessment (C)

APPROXIMATE BOUNDARY

OF

SOUTH PAHROC RANGE 

WILDERNESS STUDY AREA

(NV-050-132)<

Au 

0,G

Commodities

Gold

Oil and gas

L/C O,G

(entire study area)

[ ] Type of deposit and occurrence

1 Carbonate-hosted disseminated gold

Mine and claims

1 Flat No. 1 and No.2 claims

2 Doe claims

3 Blue Ridge claims

4 Mackie mine (Barbara claims)

5 Saphire No.1 and No.2 claims

Correlation of map units

 QUATERNARY

 TERTIARY

 ORDOVICIAN

Description of map units

Pediment gravels (Quaternary)

Tuff, andesite, and sedimentary rocks (Tertiary)-

Includes Kane Wash Tuff, Hiko Tuff, Harmony

Hills Tuff, Condor Canyon Formation, Leach

Canyon Formation, and Shingle Pass Tuff 

Rhyolite (Tertiary)--Perlite and flow-banded

devitrified obsidian 

EurekaQuartzite (Ordovician)-Sugary-textured white

quartzite with iron-stained fractures 

Pogonip(?) Group (Ordovician)-Bedded grey

limestone, dolomite, and shale locally altered to

jasperoid

Qp

Qp 

Tt

Tr

Oe

Op

 Contact

 Fault-Dotted where concealed 

x^ Claim-Number refers to table 1 

X Mackie mine-Number refers to table 1; identified perlite resource

4 MILES

Figure 2. Map showing mineral resource potential of South Pahroc Range Wilderness Study Area, Nevada.

A4 Mineral Resources of Wilderness Study Areas Southeastern Nevada
million, making the district one of Nevada's premiere early 

gold producers (Callaghan, 1937).

Mines, Prospects, Mining Claims, and Mineralized Zones

U.S. Bureau of Land Management records indicate that 

five placer claim groups, covering 1,060 acres, lie adjacent to 

and partly within the study area. The Rat No. 1 and 2, Doe, 

Blue Ridge, Barbara (Mackie mine), and Saphire No. 1 and 2 

placer perlite claims (fig. 2, Nos. 1-5) were examined during 

this study. All claims, except for parts of the Blue Ridge and 

Saphire properties and a short extension of underground 

workings at the Mackie mine, are outside the study area. None 

of the claims are patented, and only the Mackie mine is active. 

Descriptions of the mine, claims, and mineralized zones are 

listed in table 1.

Identified Resources

An indicated perlite resource of about 6 million tons is 

present just inside the study area's northeast boundary. Most 

of the resource is not amenable to surface-mining methods 

because of its position on a steep cliff beneath a dense cap 

rock. Detailed laboratory tests by the New Mexico Bureau of 

Mines and Mineral Resources show that the perlite has exceptional expansion characteristics; expanded densities range 

from 1.63 to 4.56 lb/ft3 (pounds per cubic foot). This expansion is two to three times greater than that of a standard perlite. 

However, because it does expand so well, the compaction 

resistance is very low, precluding it from use in aggregate and 

concrete. Due to its excellent expansibility, a good furnace 

yield, and a negligible nonexpandable fraction, the New 

Mexico Bureau of Mines summarized the tests on the perlite 

as follows: "As an overall evaluation, the 'light weight' end 

uses, for example, filter aid or cryogenics, would be well 

served with these samples."

Most high-bulk, low-cost commodities such as perlite 

depend on low-cost open-pit mining and low transportation 

costs. Because of prohibitively high underground mining and 

transportation costs, the perlite deposit within the study area 

could not effectively compete with established open-pit deposits closer to major markets. Opening a new mine would not 

be feasible, either, because the Mackie mine already meets regional demands for high-expansion perlite. For these reasons, 

the perlite deposit in the study area is classified as an indicated 

subeconomic resource. A substantial increase in demand for 

high-expansion perlite, especially in the Las Vegas area, 

could change the classification to that of a marginal reserve. 

It seems unlikely that the deposit within the study area would 

be exploited in the near future.

One sample from a jasperoid outcrop on the study area's 

southeast border contained a significant amount of gold 

(Neumann, 1986). No gold resources were identified in this 

area.

Apache tears (marekanite nodules), prized by rock collectors and often sold in rock shops, are abundant in the

northeast corner of the wilderness study area. They weather 

out of the perlite and litter slopes below the outcrops.

ASSESSMENT OF MINERAL RESOURCE POTENTIAL

By Barry C. Moring, H. Richard Blank, Jr., and

Harlan N. Barton

U.S. Geological Survey

Geology

The South Pahroc Range Wilderness Study Area lies in 

the southeastern part of the Basin and Range physiographic 

province. The range primarily consists of a slightly westdipping sequence of partially to completely welded ash-flow 

tuff that ranges in composition from dacite to comendenite 

and rhyolite and in age from 14 to 25 million years before 

present (Ma). These ash flows consist of the Kane Wash, 

Hiko, and Harmony Hills Tuffs, the Condor Canyon and 

Leach Canyon Formations, and the Shingle Pass Tuff (Ekren 

and others, 1977; Moring, 1987). Rhyolite and andesite flows 

and volcaniclastic sedimentary rocks are intercalated with the 

ash flow sheets. The Tertiary rocks have a total thickness of 

about 2,000 ft. The rhyolite flows commonly have been 

hydated to perlite. Tertiary strata unconformably overlie 

Paleozoic quartzite, shale, and carbonate rocks that are exposed in two places in the study area, both adjacent to the 

Pahroc fault at the base of the range. The northern exposure 

consists of a pod of broken Eureka Quartzite less than 100 yd 

across. The southern exposure consists of interbedded cherty 

limestone and shale of the Pogonip(?) Group. This unit has 

been locally altered to jasperoid.

The tilting and unroofing of the Paleozoic bedrock prior 

to the deposition of the 25-Ma Shingle Pass Tuff (Ekren and 

others, 1977) is probably the earliest evidence for Tertiary 

tectonic activity in the South Pahroc Range. Basin-andRange style faulting along the Pahroc fault system that formed 

thepresentrange probably was initiated after deposition of the 

19-Ma Hiko Tuff (Noble and McKee, 1972) and before the 

14-Ma Kane Wash Tuff (Noble, 1968). Movement along this 

fault system appears to have ceased prior to the development 

of Quaternary pediments that surround the range.

Geochemistry

The U.S. Geological Survey collected 12 rock samples, 

59 stream-sediment samples, and 59 nonmagnetic heavymineral concentrate samples from the study area in 1983. The 

stream-sediment and heavy-mineral concentrate samples 

represent material eroded from drainage basins, and chemical 

analyses of such samples are useful in identifying areas with 

mineral resource potential by delineating geochemically 

anomalous basins. Samples were analysed for 31 elements 

including silver, arsenic, barium, copper, molybdenum, tin, 

and zinc using a six-step semiquantitative emission

Mineral Resources of the South Pahroc Range Wilderness Study Area, Lincoln County, Nevada AS
spectrographic method (Grimes and Marranzino, 1968). 

Statistical treatment of these analyses indicate the presence of 

minor barium, lead, and tin anomalies scattered throughout 

the study area. These anomalies are probably due to lithologic 

variation or minor leakage along fault zones and do not fit a 

currently known resource model (Barton and Day, 1984).

Following the discovery of jasperoid and iron-stained, recry stallized limestone during field mapping in the fall of 1984, 

15 rock samples (8 collected by the U.S. Bureau of Mines and 

7 by the U.S. Geological Survey) and 2 sediment samples 

were analyzed by quantitative methods for pathfinder elements commonly associated with epithermal gold deposits: 

arsenic, gold, mercury, and antimony. One sample contains 3 

ppm gold but no pathfinder elements (Neumann, 1986). Two 

samples contain arsenic (8 and 25 ppm) and antimony (3 and 

5 ppm) (RE. Lichte, U.S. Geological Survey, written commun., 1986), three samples contain mercury (0.02 to 0.04 

ppm) (S.A. Wilson, U.S. Geological Survey, written commun., 1987), and four samples contain tungsten (1.4 to 4.3 

ppm) (P.J. Aruscavage, written commun., 1987). The gold, 

tungsten, antimony, and higher arsenic concentrations appear 

to be anomalous as they are significantly above background 

values for unmineralized Preble Limestone at the Preble disseminated-gold mine in northern Nevada (W.C. Bagby, U.S. 

Geological Survey, written commun., 1987).

Geophysics

The regional aeromagnetic coverage of the study area and 

vicinity is provided by a residual total-intensity anomaly map 

of the Caliente l°by 2° quadrangle (Saltus and Snyder, 1986), 

which incorporates maps previously released by the U.S. 

Geological Survey (1973, 1976). The area of interest was 

flown at 1-mi traverse spacing and at a barometric altitude of 

9,000 ft. Regional gravity coverage is provided by a complete 

Bouguer anomaly map of the Caliente quadrangle (Healy and 

others, 1981); a geologic interpretation of the gravity map was 

done by Snyder (1983). Widely spaced (3 mi) aeroradiometric and aeromagnetic traverses were also flown across the 

range during the National Uranium Resource Evaluation 

(NURE) program.

The South Pahroc Range straddles an east-trending belt 

of steep aeromagnetic gradients associated with the northern 

limit of strongly magnetized anomaly sources near the south 

boundary of the study area. As virtually all exposures in the 

range are silicic volcanic rocks, the source rocks are likely to 

be more mafic in composition than rocks farther north, or else 

they are substantially thicker. They may include hypabyssal 

intrusions, which typically produce intense anomalies if they 

have even a moderate magnetic content. By contrast, the 

range is situated on a north-trending Bouguer gravity gradient 

that is nearly perpendicular to the aeromagnetic gradient. This 

gradient is relatively weak and irregular; the drop in Bouguer 

levels across the range is only about 10 milligals. It can be 

ascribed to the dense carbonate rocks exposed to the west of, 

and in the shallow subsurface of, the Hiko Range and to thick,

low-density alluvium in Delamar Valley to the east. Neither 

the numerous faults nor the strongly magnetized rocks of the 

South Pahroc Range produce density contrasts of sufficient 

magnitude to be reflected in the regional gravity field.

The NURE data have been examined by J.S. Duval (written commun., 1985) of the U.S. Geological Survey, who 

reports evidence of "moderate" radioactivity within the wilderness study area, indicating concentration of 2.5 to 3.0 

percent potassium, 3.0 to 4.0 ppm equivalent uranium, and 11 

to 15 ppm equivalent thorium. These values are typical of 

silicic to intermediate volcanic rocks, and no anomalous concentrations of the radioelements were detected.

MINERAL AND ENERGY RESOURCE POTENTIAL

Several disseminated gold deposits in central and northern Nevada have formed in Paleozoic strata similar to that of 

the Pogonip(?) Group found along the southeast border of the 

study area. The gold typically occurs as micron-sized grains 

disseminated in irregular bodies of limestone, carbonaceous 

shale, and jasperoid with widely varying gold grades. The 

gold in these deposits is associated with anomalous concentrations of arsenic, mercury, antimony, thallium, and tungsten 

(Berger, 1986). These deposits are often highly silicified, are 

associated with fracture systems, or are present at contacts 

with overlying volcanic rocks as in the nearby Viola district 

(Tschanz and Pampeyan, 1970) and Atlanta district 90 mi 

northeast of the study area (E.H. Pampeyan, U.S. Geological 

Survey, written commun., 1987).

Of the 15 jasperoid samples collected and analyzed for 

this project, 4 contain higher concentrations of gold, arsenic, 

tungsten, or antimony than those expected for unmineralized 

limestones found in Nevada (W.C. Bagby, oral commun., 

1987). In addition, mercury (found in only three samples) was 

found in both samples that have anomalous arsenic and antimony. Because these values and the geologic setting are 

consistent with a carbonate-hosted disseminated-gold deposit, the rocks of the Pogonip(?) Group in the study area have 

a moderate resource potential for gold with a certainty level of 

C.

No oil or gas production has occurred near the study area, 

but Paleozoic sedimentary rocks that lie beneath the Tertiary 

volcanic rocks of the study area may be potential petroleum 

sources. Sandberg (1983) includes this area in his "cluster 

10," much of which has been thermally overmatured but may 

still contain petroleum products. Accordingly, the entire 

study area has a low resource potential for oil or gas with a 

certainty level of C.

The only geothermal activity in the region is the thermal 

springs at Ash Springs and Caliente, 6 mi west and 30 mi east 

of the study area, respectively (fig. 1). However, no thermal 

springs are known to be present in the South Pahroc Range. 

Therefore, the study area has no potential for geothermal 

energy.

A6 Mineral Resources of Wilderness Study Areas Southeastern Nevada
Perlite and Apache tears are restricted to hydrated parts of 

ancient glassy-rhyolite flows. Neumann (1986) estimated 

that an indicated, subeconomic perlite resource of about 6 

million tons is present in Tertiary rhyolite flows just inside the 

northeast boundary of the study area. However, as these are 

the only rhyolite flows that crop out in the study area there is 

no mineral resource potential for perlite outside of those 

reserves. Additional Apache tears probably await discovery 

in the vicinity of the Tertiary rhyolite. These, however are not 

considered a resource, but may be of continued intermittent, 

casual interest.

Aeroradiometric studies indicate that the radioactivity of 

the area is typical for silicic to intermediate volcanic rocks. No 

anomalous concentration of radioactive elements was detected.

REFERENCES CITED

Barton, H.N., and Day, G.W., 1984, Reconnaissance of the 

South Pahroc/Hiko Bureau of Land Management Wilderness Study Area (NV 050-0132), Lincoln County, Nevada: 

U.S. Geological Survey Open-File Report 84-362, 26 p.

Beikman, H.M., Hinkle,M.E., Frieders,Twila, Marcus, S.M., and 

Edward, J.R., 1983, Mineral surveys by the Geological 

Survey and the Bureau of Mines of Bureau of Land Management Wilderness Study Areas: U.S. Geological Survey 

Circular 901, 28 p.

Berger, B.R., 1986, Descriptive model of carbonate-hosted AuAg, in Cox, D.P., and Singer, D.A., eds., Descriptive deposit 

models: U.S. Geological Survey Bulletin 1693, p. 175.

Callaghan, Eugene, 1937, Geology of the Delamar district, 

Lincoln County, Nevada: Nevada University Bulletin, v. 

31, no. 5, Geology and Mineral Serial no. 30A, 72 p.

Ekren, E.B., Orkild, P.P., Sargent, K.A., and Dixon, G.L., 1977, 

Geologic map of Tertiary rocks, Lincoln County, Nevada: 

U.S. Geological Survey Miscellaneous Investigations Series 

Map 1-1041, scale 1:250,000.

Goudarzi, G.H., 1984, Guide to preparation of mineral survey 

reports on public lands: U.S. Geological Survey Open-File 

Report 84-787, 51 p.

Great Basin GEM Joint Venture, 1983, Grapevine Spring GEM 

Resource Area (GRA No. NV-23): Technical report prepared for the U.S. Bureau of Land Management (contract 

YA-554-RFP2-1054), 36 p.

Grimes, D.J., and Marranzino, A.P., 1968, Direct-current arc 

and alternating-current spark emission spectrographicfield 

methods for the semiquantitative analysis of geologic materials: U.S. Geological Survey Bulletin 591, 6 p.

Healy, P.L., Snyder, D.B., Walh, R.R., and Currey, F.E., 1981, 

Complete Bouguer gravity map of Nevada: Caliente sheet: 

Nevada Bureau of Mines and Geology, Map 70, scale 

1:250,000.

Moring, Barry, 1987, Geologic map of the South Pahroc Range, 

Lincoln County, Nevada: U.S. Geological Survey Miscellaneous Field Studies Map MF-1917, scale 1:48,000.

Neumann, T.R., 1986, Mineral resources of the South Pahroc 

Range Wilderness Study Area, Lincoln County, Nevada: 

U.S. Bureau of Mines Open-File Report MLA 56-86, 21 p.

Noble, D.C., 1968, Kane Springs Wash volcanic center, Lincoln 

County, Nevada, in Eckel, E.B., ed., Nevada Test Site: 

Geological Society of America Memoir 110, p. 109-116.

Noble, D.C., and McKee, E.H., 1972, Description and K-Ar ages 

of volcanic units of the Caliente volcanic field, Lincoln 

County, Nevada, and Washington County, Utah: Isochron/ 

West, no. 5, p. 17-24.

Saltus, R.W., and Snyder, D.B., 1986, Aeromagnetic map of 

Nevada; Caliente sheet: Nevada Bureau of Mines and 

Geology Map 89, scale 1:250,000.

Sandberg, C.A., 1983, Petroleum potential of wilderness lands 

in Nevada, in Miller, B.M., ed., Petroleum potential of wilderness lands in the western United States: U.S. Geological 

Survey Circular 902-H, 11 p.

Snyder, D.B., 1983, Interpretation of the Bouguer gravity map of 

Nevada: Caliente sheet: Nevada Bureau of Mines and Geology, Report 37, 8 p.

Tschanz, C.M., and Pampeyan, E.H., 1970, Geology and mineral deposits of Lincoln County, Nevada: Nevada Bureau 

of Mines Bulletin 73, 187 p.

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

U.S. Geological Survey Circular 851, 5 p.

U.S. Geological Survey, 1973, Aeromagnetic map of southeastern part of Lund and eastern half of Caliente 1° x 2° degree 

quadrangles, Nevada: U.S. Geological Survey Open-File 

Report 73-298, scale 1:250,000.

U.S. Geological Survey, 1976, Aeromagnetic map for parts of 

the Caliente and Lund 1° x 2° quadrangles, Nevada: U.S. 

Geological Survey Open-File Report 76-364, scale 

1:125,000.

Mineral Resources of the South Pahroc Range Wilderness Study Area, Lincoln County, Nevada A7
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A8 Mineral Resources of Wilderness Study Areas Southeastern Nevada
APPENDIXES
DEFINITION OF LEVELS OF MINERAL RESOURCE POTENTIAL 

AND CERTAINTY OF ASSESSMENT

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 permissive. 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 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 occurence, where interpretations of 

data indicate a high degree of likelihood for resource accumulation, where data supports 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

o

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

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. J., 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 84-4)787, p. 7, 8.

A10 Mineral Resources of Wilderness Study Areas Southeastern Nevada
RESOURCE/RESERVE CLASSIFICATION

ECONOMIC

MARGINALLY 

ECONOMIC

SUBECONOMIC

IDENTIFIED RESOURCES

Demonstrated

Measured Indicated

I 

I 

Reserves

I 

ir^

I 

Marginal 

Reserves

I

I

Demonstrated 

Subeconomic 

Resources

i

Inferred

Inferred 

Reserves

Inferred 

Marginal 

Reserves

Inferred 

Subeconomic 

Resources

UNDISCOVERED RESOURCES

Probability Range

Hypothetical Speculative

Major elements of mineral resoufce 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.

Mineral Resources of the South Pahroc Range Wilderness Study Area, Lincoln County, Nevada A11
GEOLOGIC TIME CHART 

Terms and boundary ages used by the U.S. Geological Survey in this report

EON

Phanerozoic

Proterozoic

Archean

ERA

Cenozoic

Mesozoic

Paleozoic

Late Proterozoic

Middle Proterozoic

Early Proterozoic

Late Archean

Middle Archean

Early Archean

PERIOD

Quaternary

Tertiary

Neogene 

Subperiod

Paleogene 

Subperiod

Cretaceous

Jurassic

Triassic

Permian

Carboniferous 

Periods

Pennsylvanian

Mississippian

Devonian

Silurian

Ordovician

Cambrian

pre -Archean 2

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

AGE ESTIMATES 

OF BOUNDARIES 

(in Ma)

- 0.010

- 1.7

- 5

\j

- 24

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_ CC

- 96 

_ no

one

*.*TW

- 290 £.&\J 

OOrt - ~330

Oftfl

- 410

"w^J

- 500

o/u

Q/1/1

r- 1600

__ e\ cf\f\

- 3000 

 7400 O"TV/V

'Rocks older than 570 Ma also called Precambrian, a time term without specific rank. 

Informal time term without specific rank.

A12 Mineral Resources of Wilderness Study Areas Southeastern Nevada

GPO 585-045/78043