Mineral Resources of the Black Rock Desert 

Wilderness Study Area, 

Humboldt County, Nevada

U.S. GEOLOGICAL SURVEY BULLETIN 1726-E

Chapter E

Mineral Resources of the

Black Rock Desert Wilderness Study Area,

Humboldt County, Nevada

By J.P. CALZIA, W.A. LAWSON, J.C. DOHRENWEND, DONALD PLOUFF, 

and ROBERT TURNER 

U.S. Geological Survey

J.E. OLSON

U.S. Bureau of Mines

U.S. GEOLOGICAL SURVEY BULLETIN 1726

MINERAL RESOURCES OF WILDERNESS STUDY AREAS: 

HUMBOLDT AND PERSHING COUNTIES, NEVADA
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 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 Black Rock Desert Wilderness 

Study Area, Humboldt County, Nevada.

U.S. Geological Survey Bulletin 1726-E (Mineral resources

of wilderness study areas Humboldt and Pershing

counties, Nevada ; ch. E)

Bibliography

Supt. of Docs. No.: I 19.3:1726-E

1. Mines and mineral resources Nevada Black Rock

Desert Wilderness. 2. Black Rock Desert Wilderness (Nev.)

I. Calzia, J.P. II. Series. III. Series: U.S. Geological Survey

Bulletin 1726.

QE75.B9 No. 1726-E 557.3s 87-600346 

[TN24.N3] [553'.09793'54]
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 

Black Rock Desert Wilderness Study Area (NV-020-620), Humboldt County, Nevada.

CONTENTS

Summary El

Abstract 1

Character and setting 1

Mineral resources 1 

Introduction 3

Location and physiography 3

Previous work 3

Methods 3

Acknowledgments 3 

Appraisal of identified resources 3

Mining history and current activity 3

Mineral deposits 4 

Assessment of mineral resource potential 5 i

Geology 5

Geochemistry 6

Geophysics 6

Mineral resource potential 6 

References cited 7 

Appendixes

Definition of levels of mineral resource potential and certainty 

of assessment 11

Resource/reserve classification 12

Geologic time chart 13

FIGURES

1. Index map showing location of the Black Rock Desert Wilderness Study Area, 

Humboldt County, Nevada E2

2. Map showing mineral resource potential of the Black Rock Desert Wilderness 

Study Area, Humboldt County, Nevada 4

MINERAL RESOURCES OF WILDERNESS STUDY AREAS: 

HUMBOLDT AND PERSHING COUNTIES, NEVADA

Mineral Resources of the

Black Rock Desert Wilderness Study Area,

Humboldt County, Nevada

By J.P. Calzia, W.A. Lawson, J.C. Dohrenwend, Donald Plouff, 

and Robert Turner 

U.S. Geological Survey

J.E. Olson

U.S. Bureau of Mines

SUMMARY 

Abstract

The Black Rock Desert Wilderness Study Area 

(NV-020-620) covers 319,594 acres in western 

Humboldt County, Nev. The U.S. Bureau of Land 

Management requested mineral surveys on 174,300 

acres of the wilderness study area. An appraisal of 

identified resources (known) and assessment of the 

mineral resource potential (undiscovered) of the 

smaller area, hereafter designated the study area, are 

described in this report. Geologic, geochemical, 

geophysical, and mineral surveys indicate that the 

study area has moderate potential for gold, silver, 

mercury, lithium, and geothermal resources and low 

potential for oil and gas resources although no mines 

or prospects were identified within this area.

Character and Setting

The Black Rock Desert Wilderness Study Area 

consists of a flat playa within the Black Rock Desert 

that is bounded by the Black Rock Range to the west 

and by the Jackson Mountains to the east. A group of 

north-trending hills, buttes, and mesas borders the 

study area to the northwest. Elevations on the playa 

range from 3,900 to 4,000 ft.

The Black Rock Desert is in the Basin and Range 

physiographic province. This province is characterized 

by northwest-trending fault-bounded mountains 

separated by wide parallel valleys. The Black Rock 

Desert is within a down-dropped fault block that is

filled by Cenozoic sediments. Hills and mesas 

northwest of the study area are underlain by TriassicJurassic (see appendix for geologic tine chart) 

phyllite, quartzite, and limestone, Cretaceous quartz 

monzonite, and Miocene-Pliocene tuffs, rhyolite flows, 

and basalt.

Mineral Resources

No mines are known or reported within the study 

area; the area has no identified resources. Rock and 

sinter samples collected near Pinto Hot Springs (fig. 1) 

contain low but anomalous concentrations of gold, 

silver, antimony, arsenic, barium, and mercury. This 

area has moderate resource potential for gold, silver 

and mercury in hot-spring deposits (fig. 2).

Lacustrine sediments have moderate resource 

potential for lithium. These sediments contain low 

lithium values and the geologic conditions are 

favorable for the concentration of lithium at depth.

All of the study area has moderate potential for 

geothermal resources. The Pinto Hot Springs Known 

Geothermal Resource Area (KGRA) and an unnamed 

hot spring are located near the north and south 

boundary of the study area, respectively. Nearly 

27,000 acres are under lease near these geothermal 

areas.

The Black Rock Desert is classified prospectively 

valuable for oil and gas resources by the U.S. Bureau 

of Land Management (BLM). A recently completed oil 

and gas exploration well in the southeast corner of the 

study area was dry. The test well data suggest that 

the study area has low potential for oil and gas 

resources.

E1
41°30'

41°00'

119°00' 

I

IIS^S' 

I

118°30'

Pinto Hot Springs

Known Geothermal

Resource Area

Pahute Meadows 

Ranch

Double Hot Springs

Known Geothermal

Resource Area

HUMBOLDT CO 

PERSHING CO__ J

Pidgeon Spring

BLACK ROCK DESERT 

WILDERNESS STUDY AREA 

(NV-020-620)

»'Sulphur AREA OF AAAP

Figure 1. Index map showing location of the Black Rock Desert Wilderness Study Area, Humboldt County, Nevada.

E2
INTRODUCTION Methods

This mineral resource study is a joint effort by 

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

Mines. Studies by the U.S. Geological Survey are 

designed to provide a reasonable scientific basis for 

assessing the potential for undiscovered mineral 

resources by determining geologic units and structures, 

possible environments of mineral deposition, presence 

of geochemical and geophysical anomalies, and 

applicable ore-deposit models. The U.S. Bureau of 

Mines evaluates identified 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). Levels of 

mineral resource potential, certainty of assessment, 

and classification of identified resources are defined in 

the appendix.

Location and Physiography

The study area within the Black Rock Desert 

Wilderness Study Area (NV-020-620) covers 174,300 

acres in western Humboldt County, Nev. The study 

area includes a large playa, located within the Black 

Rock Desert, bounded on the west and east by the 

Black Rock Range and the Jackson Mountains, 

respectively (fig. 1). Elevations on the playa range 

from 3,900 to 4,000 ft. The climate is arid. 

Vegetation, including saltbrush, grass, and greasewood, 

is very thick along the margin and in the northern third 

of the study area. The remainder of the playa is 

barren.

Access to the study area is permitted via Nevada 

Highway 140 between Winnemucca and Denio Junction, 

Nev. The Leonard Creek Ranch Road, a wellmaintained dirt road, extends from Quinn River 

Crossing to Pahute Meadows Ranch (fig. 1). East-west 

vehicle traverses on the playa are possible only at the 

extreme southern end of the study area near Sulphur, 

and at the extreme north end along Leonard Creek 

Ranch Road. North-south traverses on either side of 

the Quinn River are possible with a four-wheel drive 

vehicle.

Previous Work

The geology and mineral resources of Humboldt 

County and northwest Nevada are described by Beatty 

(1955) and Willden (1964). Willden (1963), Sorensen 

(1986), and Sorensen and others (1987) described the 

geology and mineral resources of the Jackson 

Mountains. Lithium occurrences in Nevada are 

discussed by Vine and Dooley (1980). Barringer 

Resources, Inc. (1982), compiled reconnaissance 

geochemical and geostatistical data of the study area 

for the BLM.

The U.S. Geological Survey completed field 

investigations of the study area during the fall of 

1985. The playa and the eastern margin of the Black 

Rock Range were mapped at 1:24,000 scale. Samples 

of the playa sediments and volcanic rocks along the 

west boundary of the study area were collected for 

geochemical and petrographic study. Water samples of 

hot springs adjacent to the study area were collected 

to determine mineral content and geothermal 

potential.

The U.S. Bureau of Mines (USBM) investigations 

included library research, a search of BLM and 

Humboldt County mining records for claim locations, 

and an examination of USBM production and Mineral 

Industries Location System records. Claim owners 

were contacted for additional information and to 

obtain permission to examine and publish data about 

their properties.

USBM field work in 1984 included examination of 

all known mineral properties within and immediately 

adjacent to the study area (Olson, 1985). Aerial and 

ground reconnaissance surveys were conducted to find 

new claims, prospects, or mineralized areas. All 

known and new sites were sampled and, if warranted, 

mapped. Detailed information is available from the 

U.S. Bureau of Mines, Western Field Operations 

Center, E. 360 Third Street, Spokane, WA 99202.

Acknowledgments

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

of Mines thank Willis Bland for allowing us to establish 

base camps at Pahute Meadows Ranch and for his 

assistance in many logistical matters. Victor Dunn, 

BLM Winnemucca District, provided valuable 

information on the geologic and mineral character of 

the study area.

APPRAISAL OF IDENTIFIED RESOURCES

By_ J.E. Olson

U.S. Bureau of Minqs

Mining History and Current Activity

Emigrants and prospectors enroute to the 

California gold fields began prospecting in Humboldt 

County around 1850. The Sulphur mining district, at 

the south end of the study area, evolved around 1870 

when Indians first showed prospectors the location of 

native sulfur (Bailey and Phoenix, 1944). In 1908, rich 

silver veins were discovered at the south end of the 

district (Vanderburg, 1938). Production from the 

Sulphur mining district through 1920 totaled 15,369 

tons of silver (Bailey and Phoenix, 1944). Mercury 

mining began about 1941 although cinnabar had been 

noted as early as 1882. Reported mercury production 

was 25 flasks through 1943. An old mining area near 

Sulphur was under development in 1984 as an open pit 

gold mine.

E3
Current mineral interest in the study area 

consists of geothermal and oil and gas leases. 

Geothermal leases cover approximately 27,000 acres 

near Pinto Hot Springs and the unnamed hot spring 

near the southeast corner of the study area. Oil and 

gas leases cover most of the Black Rock Desert.

Mineral Deposits

No mines or prospects were identified within the 

study area. Twenty three small prospect pits and 

trenches are located in extremely fine-grained 

silicified rock north of Pinto Hot Springs. Seven

APPROXIMATE BOUNDARY 

OF

BLACK ROCK DESERT

WILDERNESS STUDY AREA

(NV-020-620)

M/C Gco 

L/C 0,G 

(Entire area)

Figure 2. Mineral resource potential of the Black Rock Desert Wilderness Study Area, Humboldt County, 

Nevada.

E4
representative samples from these pits contain 0.009 

to 0.064 parts per million (ppm) gold. One sample 

from a pit located on a fault zone west of the hot 

springs contains 0.478 ppm gold and 120 ppm arsenic.

One small prospect pit was found near Pahute 

Creek just west of the study area. A sample of 

tuffaceous rocks near the pit contains 0.027 ppm gold 

and 1.87 ppm silver.

Samples of playa sediments near Leonard Creek 

at the north boundary of the study area contain 

anomalous concentrations of molybdenum and tungsten 

that are attributed to outwash from the Leonard Creek 

drainage basin. Samples of gravel from Leonard Creek 

contained a maximum 0.0002 troy ounce per cubic yard 

(oz/yd-*) gold.

The Pidgeon Spring area is underlain by Tertiary 

tuffs and younger playa deposits. One sample from a 

rhyolitic tuff contains 0.040 ppm gold and 59 ppm 

arsenic.

The playa deposits within the study area contain 

lithium and zeolite minerals. Lithium values range 

from 20 to 60 ppm. Davis (1976) suggests that lithium 

in surface clays may be anomalous at values exceeding 

300 ppm. Zeolite minerals within the playa sediments 

are rare and are not of commercial interest.

EXPLANATION

Area with moderate mineral resource potential-Entire 

study area has moderate potential for geothermal 

resources

Area with low mineral resource potential-Entire study 

area has low potential for oil and gas resources

See appendix for definition of levels of resource potential and certainty 

of assessment

Commodities

Au Gold

Ag Silver

Hg Mercury

Li Lithium

Geo Geothermal

O.G Oil and gas

Geologic map units

Qal Alluvium including hot-spring deposits (Holocene

	and Pleistocene)

Qpe Playa and aeolian sand deposits (Holocene)

Ql Lacustrine deposits of Lake Lahontan (Pleistocene)

Ttb Tuffs and basalts (Oligocene and Miocene)

Kqm Quartz monzonite (Cretaceous)

JT Quartzite, phyllite, and limestone (Jurassic or Triassic)

 Contact-Dashed where approximately located

-* % Normal fault-Dashed where approximately located;

dotted where concealed; ball and bar on downthrown 

side; D on downthrown side; U on upthrown side

Figure 2. Continued.

ASSESSMENT OF MINERAL RESOURCE POTENTIAL

By J.P. Calzia, W.A. Lawson, J.C. Dohrenwend, 

Donald Plouff, and Robert Turner 

U.S. Geological Survey

Geology

The Black Rock Desert Wilderness Study Area is 

mostly underlain by Pleistocene and Holocene 

lacustrine sediments that unconformably overlie 

igneous and metamorphic rocks of Triassic to Tertiary 

age. The lacustrine sediments are overlain by and are 

intercalated with playa, eolian, fluvial, and younger 

alluvial fan deposits.

The oldest rocks in the Black Rock Range include 

Triassic or Jurassic quartzite, phyllite, and gray 

limestone (Stewart and Carlson, 1978). These rocks 

are intruded by a small Cretaceous quartz monzonite 

pluton and by aplite dikes. The aplite dikes cut the 

quartzite about 1 mi northwest of Pinto Hot Springs.

Late Olipocene and Miocene tuffaceous rocks 

and basalt flows unconformably overlie the preTertiary rocks along the west side of the study area. 

The tuffaceous rocks consist of air-fall and waterlain 

massive to laminated tuffaceous sandstone, siltstone, 

diatomaceous shale, and pumiceous tuff breccia. 

Welded rhyolitic tuffs and vesicular basalt flows are 

interbedded with the tuffaceous deposits. The welded 

tuff is similar in composition and may be the Ashdown 

Tuff (D.C. Noble, oral commun., 1980). Sanidine from 

the Ashdown Tuff in the northern Black Rock Range 

yields potassium-argon ages of 23.7 to 25.3 million 

years (Ma) (Noble and others, 1970).

Basalt flows north of Pinto Hot Springs, 

characterized by abundant plagioclase phenocrysts and 

diktytaxitic textures, may correlate with the Steens 

Basalt. The Steens just north of the study area yields 

whole-rock potassium-argon ages of 15.4 and 16.6 Ma 

(Hart and Carlson, 1985).

Elephant Mountain west of the study area is a 

rhyolite plug flanked by rhyolite flows and tuffs. The 

rhyolite flows are locally . flow banded and contain 

phenocrysts of quartz, sanidine, and biotite. The lower 

parts of the rhyolite flows are highly silicified. The 

tuffs are locally welded and contain perlite.

Tertiary rocks in the Black Rock Range are 

overlain by upper Pleistocene lacustrine sediments of 

Lake Lahontan. The Lake Lahontan shoreline that 

rings the Black Rock Desert forms a nearly continuous 

series of beach ridges, wave-cut notches, and cliffs at 

an approximate elevation of 4,370 ft. Littoral and 

nearshore sediments are characterized by multiple 

strandlines and beach ridges of well-sorted sand and 

gravel. These strandlines are especially prominent 

along the south and east margins of the Black Rock 

Desert. Locally, littoral sediments also form large 

spits. These relict features are particularly well 

developed near the highest shoreline and near the 

margins of the playa. Extensive lacustrine deposits in 

the north half of the study area form nearly flat-lying 

beds of predominantly fine sand, silt, and clay. All the 

lacustrine sediments have been pervasively dissected 

by a well-developed dendritic network of Holocene 

stream channels and are largely buried by eolian sand 

sheets and dunes.

E5
Holocene playa sediments consist of clay, silt, 

and fine sand with minor evaporite salts. Interbedded 

lenses of fine sand and gravel are present near the 

playa margins. The playa sediments have little to no 

relief or dissection. They are intercalated with 

younger alluvial fans and fluvial sediments along the 

playa margins and are locally overlain by eolian 

deposits.

Eolian deposits consist of well-sorted, mediumto fine-grained sand. These deposits form extensive 

sand sheets and fields of coppice to barchanoid dunes. 

The sand sheets are generally less than 2 ft thick. The 

sand dunes range between 3 and 15 ft high; a few dunes 

exceed heights of 30 ft. The largest and highest dunes 

are mobilized beach ridges that are found along the 

south and east margins of the playa.

Fluvial sediments consist of moderately to poorly 

sorted silty sand and sandy to clayey silt reworked 

from the eolian and lacustrine deposits. The fluvial 

sediments include channel and flood-plain deposits 

along the Quinn River. Channels and flood plains 

generally range between 0.25 and 1.0 mi in aggregate 

width and are incised as much as 15 ft into the 

lacustrine sediments.

The alluvial fans consist of poorly sorted 

boulders, cobbles, and pebbles that reflect the 

composition of their source area. Younger alluvial 

fans form thin veneers, generally less than 15 ft thick, 

over the lacustrine and playa deposits.

Geochemistry

Geochemical studies within the study area 

consist of a reconnaissance survey by Barringer 

Resources, Inc. (1982), and a subsequent more detailed 

survey by the U.S. Geological Survey of anomalous 

areas that were defined by the reconnaissance 

survey. Barringer Resources, Inc. (1982), collected 269 

samples within the study area. Approximately 90 

percent of these samples are lacustrine sediments. 

Chemical data from these samples are difficult to 

evaluate because the lacustrine samples represent a 

composite of weathering products from several 

drainage basins that cover hundreds of square miles 

around the study area. There is no way to determine 

the source of any anomaly based on these sample data.

Detailed geochemical studies were made in the 

Pinto Mountain and the Elephant Mountain areas 

because these areas include the only large rock 

outcrops in or near the study area. Rock and 

nonmagnetic heavy-mineral concentrate samples from 

these areas were crushed and analyzed for 31 elements 

using techniques described by Grimes and Marranzino 

(1968). The rock samples were also analyzed for 

antimony, arsenic, bismuth, and zinc using techniques 

described by Crock and others (1983), and for gold and 

mercury using techniques described by Thompson and 

others (1968) and Koirtyohann and Khalil (1976), 

respectively.

Three sinter and two tuff samples were collected 

from the Pinto Mountain area. One tuff sample 

contained 0.1 ppm gold. Arsenic ranges from less than 

5 ppm to 100 ppm, antimony ranges from less than 2 

ppm to 6 ppm, and mercury ranges from less than 0.3 

ppm to 1300 ppm. The sinter samples contained the

highest values of arsenic, antimony, and mercury. 

Samples collected southwest of Elephant Mountain 

contain 42 ppm arsenic, as much as 300 ppm lead, and 

120 ppm zinc.

Geophysics

Geophysical studies in the study area consist of 

gravity and aeromagnetic surveys. Four gravity 

stations were established by Peterson and Hassemer 

(1977) as part of the geothermal resource study of the 

Pinto Hot Springs KGRA. Data at two additional 

stations were acquired from the National Geophysical 

Data Center (1984). These data were supplemented by 

stations established along roads east and west of the 

study area by Donald Plouff, C.F. Erdmann, and V.E. 

Langenheim (unpublished data, 1984).

The study area is dominated by a broad gravity 

low with an east-west width of about 11 mi. The 

amplitude of the gravity low is roughly 30 milligals. 

The gravity data suggest that the lacustrine 

sediments are more than 5,000 ft thick, assuming a 

density contrast of 0.5 grams per cubic centimeter 

between the sediments and bedrock.

An aeromagnetic survey of the region was flown 

at a constant barometric elevation of 9,000 ft above 

sea level with east-west flightlines spaced at 2 mi 

intervals. The aeromagnetic intensity pattern over 

most of the study area is featureless because of low 

magnetization of the lacustrine sediments. The 

aeromagnetic data suggest that the lacustrine 

sediments are thickest about 1 mi west of the Quinn 

River.

Mineral Resource Potential

Geologic and geochemical data suggest that 

there is potential for several types of resources within 

the study area, even though no mines are present. 

These resources include gold, silver, and mercury 

associated with hot springs, lithium in lacustrine 

sediments, geothermal, and oil and gas. Each of these 

types of deposits are assigned moderate or low 

resource potential at various certainty levels as 

defined in the appendix.

The Pinto Hot Springs area has moderate 

potential for gold, silver, and mercury resources in 

hot-spring deposits at certainty level B. Berger (1986) 

reported that hot-spring gold-silver deposits often 

occur along fractures in brecciated rhyolitic tuffs and 

flows. Hot-spring mercury deposits occur in similar 

geologic environments and are often associated with 

hot-spring gold-silver deposits. Anomalous 

concentrations of arsenic and antimony in sinter are 

typically associated with those gold-silver and mercury 

deposits.

Lacustrine sediments within the study area have 

moderate potential for lithium resources at certainty 

level B. Lithium concentrations in near-surface 

samples ranges from 20 to 60 ppm. Bohannon and 

Meier (1976) reported that near-surface lithium values 

may not be reliable indicators of resources of depth 

because most large lithium deposits form at depth in 

deep sedimentary basins. Vine (1975) concluded that

E6
desert playas are good targets for lithium exploration 

because (1) structural basins created by block faulting 

restrict the escape of soluble clay-size constituents; 

(2) deep-seated faults may act as conduits for 

circulating groundwater; (3) high temperature 

gradients, especially near hot springs, may drive 

groundwater convection cells; and (4) excess 

evaporation relative to precipitation provides for 

lithium detection in the near-surface environment.

All of the study area has moderate resource 

potential for geothermal resources at certainty level 

C. Surface spring temperatures range from 150 to 

172 °F at Pinto Hot Springs and from 152 to 170 °F at 

the unnamed hot spring in the southeast corner of the 

study area. The BLM may declassify the Pinto Hot 

Springs KGRA because no bids were received for this 

area during geothermal lease sales held in 1984 and 

1985. This KGRA was established in 1975 on the basis 

of competitive interest and on geologic evidence.

The entire study area has low potential for oil 

and gas resources at certainty level C. Willden (1979) 

reported that the Black Rock Desert was highly 

favorable for oil and gas exploration because organicrich source rocks crop out in the Jackson Mountains 

and probably occur at depth in the Black Rock 

Desert. The BLM classified the study area as 

prospectively valuable of oil and gas resources. An 

exploratory well, located in the southeast corner of 

the study area, was completed in 1983 to a total depth 

of 7,931 ft and is dry. The test-well data suggest that 

the oil and gas potential of the Black Rock Desert is 

low.

The playa and lacustrine sediments have no 

potential for either sodium and potassium or sand and 

gravel resources. Although the Black Rock Desert is 

classified prospectively valuable for sodium and 

potassium resources by the BLM, little to no evaporite 

salts or alkali elements were noted in rock, stream 

sediment, and groundwater samples. The lack of 

evaporite salts and brines precludes the potential for 

sodium and potassium resources. Well-sorted sand and 

gravel deposits are thin and limited to ancient beach 

ridges. Larger more accessible deposits are located 

east of the study area closer to metropolitan areas.

REFERENCES CITED

Bailey, E.H., and Phoenix, D.A., 1944, Quicksilver 

deposits in Nevada: University of Nevada 

Bulletin, v. 38, p. 107-108.

Barringer Resources, Inc., 198Z, Geochemical and 

geostatistical evaluation of wilderness study 

areas, Winnemucca District, northern Nevada: 

Golden, Colo., Barringer Resources, Inc., 575 p.

Beatty, W.B., 1955, Mineral resources of northwest 

Nevada: Menlo Park, Calif., Stanford Research 

Institute Project 130Z, 40 p.

Berger, B.R., 1986, Descriptive model of hot-springs 

Au-Ag, in Cox, D.P., and Singer, D.A., eds., 

Mineral deposit models: U.S. Geological Survey 

Bulletin 1693, p. 143.

Bohannon, R.G., and Meier, A.L., 1976, Lithium in 

sediments and rocks in Nevada: U.S. Geological 

Survey Open-File Report 76-567, 17 p.

Crock, J.G., Lichte, F.E., and Briggs, P.H., 1983, 

Determination of elements in National Bureau of 

Standards geological reference materials SRM278 

obsidian and SRM668 basalt by inductively coupled 

argon plasma-atomic emission spectometry: 

Geostandards Newsletter no. 7, p. 335-340.

Davis, J.R., 1976, The influence of drainage basin area 

upon the distribution of lithium in playa 

sediments, in Vine, J.D., ed., Lithium resources 

and requirements by the Year 2000: U.S. 

Geological Survey Professional Paper 1005, p. 

105-109.

Grimes, D.J., and Marranzino, A.P., 1968, Directcurrent arc and alternating current spark emission 

spectrographic field methods for the quantitative 

analysis of geologic materials: U.S. Geological 

Survey Circular 591, 6 p.

Hart, W.K., and Carlson, R.W., 1985, Distribution and 

geochronology of Steens Mountain-type basalt 

from the northwestern Great Basin: 

Isochron/West, no. 43, p. 5-10.

Koirtyohann, S.R., and Khalil, Moheb, 1976, Variables 

in the determination of mercury by cold vapor 

atomic absorption: Analytical Chemistry, v. 48, 

p. 136-138.

National Geophysical Data Center, 1984, DMA gravity 

file of the U.S.: National Oceanic and 

Atmospheric Administration, Boulder, 2 magnetic 

tapes.

Noble, D.C., McKee, E.H., Smith, J.G., and Korriuga, 

M.K., 1970, Stratigraphy and geochronology of 

Miocene volcanic rocks in northwestern Nevada: 

U.S. Geological Survey Professional Paper 700-D, 

p. D23-D32.

Olson, I.E., 1985, Mineral Resources of the Black Rock 

Desert Wilderness Study Area, Humboldt County, 

Nevada: U.S. Bureau of Mines Open-File Report 

MLA 65-85, 19 p.

Peterson, D.L., and Hassemar, J.H., 1977, Principal 

facts for a gravity survey of Pinto Hot Springs 

Known Geothermal Resource Area, Nevada: U.S. 

Geological Survey Open-File Report 77-678, 4 p.

Sorensen, M.L., 1986, Geologic map of South Jackson 

Mountains Wilderness Study Area, Humboldt 

County, Nevada: U.S. Geological Survey 

Miscellaneous Field Studies Map MF-1829, scale 

1:48,000.

Sorensen, M.L., Plouff, Donald, Turner, R.L., and 

Hamilton, M.M., 1987, Mineral resources of South 

Jackson Mountains Wilderness Study Area, 

Humboldt County, Nevada: U.S. Geological 

Survey Bulletin 1726-B, 14 p.

Stewart, J.H., and Carlson J.E., 1978, Geologic map of 

Nevada: U.S. Geological Survey and the Nevada 

Bureau of Mines and Geology, scale 1:500,000.

Thompson, C.E., Nakagawa, H.M., and Van Side, G.H., 

1968, Rapid analysis for gold in geological 

materials: U.S. Geological Survey Professional 

Paper 600-B, p. B130-B132.

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

PVanderburg, W.O., 1938, Reconnaissance of mining 

districts in Humboldt County, Nevada: U.S. 

Bureau of Mines Information Circular 6995, 54 p.

E7
Vine, J.D., 1975, Lithium in sediments and brines-how, 

why, and where to search: U.S. Geological Survey 

Journal Research, v. 3, p. 479-485.

Vine, J.D., and Dooley, J.R., 1980, Where on earth is 

all the lithium?: U.S. Geological Survey OpenFile Report 80-1Z34, 25 p.

Willden, Ronald, 1963, General geology of the Jackson 

Mountains, Humboldt County, Nevada: U.S. 

Geological Survey Bulletin 1141-D, 65 p.

__1964, General geology and mineral deposits of 

Humboldt County, Nevada: Nevada Bureau of 

Mines Bulletin 59, 154 p.

__1979, Petroleum exploration possibilities in 

northwestern Nevada, in Newman G.W., and 

Goode, H.D., eds., Basin and Range Symposium: 

Rocky Mountain Association of Geologists and 

Utah Geological Association, p. 541-548.

E8
APPENDIXES

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 permissive. This 

broad category embraces areas with dispersed but insignificantly mineralized rock as well as areasiwith 

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

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 resouree 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

ol the San Isabel National F:orest, south-central Colorado. U S Geological Survey Bulletin 1638, p

40 42 

(joudar/i, G H , compiler, 1984, Guide to preparation of mineral survey reports on public lands. U S

Geological Survey Open F-'ile Report 84 0787, p 7, 8

E11
RESOURCE/RESERVE CLASSIFICATION

IDENTIFIED RESOURCES

Demonstrated

Measured Indicated

Inferred

UNDISCOVERED RESOURCES

Probability Range

Hypothetical Speculative

ECONOMIC

MARGINALLY 

ECONOMIC

SUBECONOMIC

Reserves Inferred 

Reserves

Marginal 

Reserves

Inferred 

Marginal 

Reserves

Demonstrated

Subeconomic

Resources

Inferred

Subeconomic

Resources

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.

E12
GEOLOGIC TIME CHART 

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

EON

Phanerozoic

Proterozoic

Archean 

pre - Ar

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

Pateocene

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

** A

oo

\J\J

 RR

- 96 

 np

one

fc"T\/

4&9V/

_ <t~Qon

- ouu TOO

- 410

- rOw 435

- 500

o/u 

 Qfln

icnn

4&%JUVF

ouuu

OHVU

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

informal time term without specific rank.

E13

Mineral Resources of 

Wilderness Study Areas: 

Humboldt and Pershing Counties, 

Nevada

This volume was published as chapters A E

U.S. GEOLOGICAL SURVEY BULLETIN 1726
DEPARTMENT OF THE INTERIOR 

DONALD PAUL MODEL, Secretary

U.S. GEOLOGICAL SURVEY 

Dallas L. Peck, Director
CONTENTS

[Letters designate the separately published chapters]

(A) Mineral resources of the Mount Limbo Wilderness Study Area, Pershing County, 

Nevada, by William J. Keith, Robert L. Turner, Donald Plouff, and Clayton M. 

Rumsey.

(B) Mineral resources of the South Jackson Mountains Wilderness Study Area, 

Humboldt County, Nevada, by Martin L. Sorensen, Donald Plouff, Robert L. 

Turner, and Michael M. Hamilton.

(C) Mineral resources of the Pahute Peak Wilderness Study Area, Humboldt County, 

Nevada, by Donald C. Noble, Donald Plouff, Joel R. Bergquist, Harlan N. Barton, 

and Jerry E. Olson.

(D) Mineral resources of the Blue Lakes Wilderness Study Area, Humboldt County, 

Nevada, by Joel R. Bergquist, Donald Plouff, Brent D. Turrin, James G. Smith, 

Robert L. Turner, and Spencee L. Willett.

(E) Mineral resources of the Black Rock Desert Wilderness Study Area, Humboldt 

County, Nevada, by J.P. Calzia, W.A. Lawson, J.C. Dohrenwend, Donald Plouff, 

Robert Turner, and J.E. Olson.
o

hd O

-j

00 

Ln 

I O

-P00

-P- o

Ln