Mineral Resources of the High Rock 

Canyon Wilderness Study Area, 

Washoe County, Nevada

U.S. GEOLOGICAL SURVEY BULLETIN 1707-D

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Chapter D

Mineral Resources of the

High Rock Canyon Wilderness Study Area,

Was hoe County, Nevada

By BRENT D. TURRIN, JOEL R. BERGQUIST, 

ROBERT L TURNER, and DONALD PLOUFF 

U.S. Geological Survey

CARL W. PONADER 

Stanford University

DOUGLAS F. SCOTT 

U.S. Bureau of Mines

U.S. GEOLOGICAL SURVEY BULLETIN 1707

MINERAL RESOURCES OF WILDERNESS STUDY AREAS: 

NORTHWESTERN 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 High Rock Canyon Wilderness Study 

Area, Washoe County, Nevada.

Mineral resources of wilderness study areas northwestern

Nevada, U.S. Geological Survey Bulletin 1707-D

Bibliography.

Supt. of Docs. No.: I 19.3:1707-D

1. Mines and mineral resources Nevada High Rock Canyon

Wilderness. 2. High Rock Canyon Wilderness (Nev.) I.

Turrin, Brent D. II. Series. III. Series: U.S. Geological Survey

Bulletin 1707-D.

QE75.B9 No. 1707-D 557.3s 87-600484 

[TN24.N3] [553'.09793'55]
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 High Rock 

Canyon Wilderness Study Area (CA-020-913B), Washoe County, Nevada.

CONTENTS

Summary Dl

Abstract 1

Character and setting 1

Identified resources 1

Mineral resource potential 3 

Introduction 3 

Appraisal of identified resources 3

Methods and scope of investigation 3

History of mining and mineral exploration 5

Identified resources 5 

Assessment of mineral resource potential 6

Geology 6

Geochemistry 6

Geophysics 6

Gamma-ray spectroscopy 6 

Aeromagnetic survey 7 

Gravity survey 7

Mineral resource potential 7 

References cited 9 

Appendixes

Definition of levels of mineral resource potential and certainty of assessment 12

Resource/reserve classification 13

Geologic time chart 14

FIGURES

1. Index map showing location of High Rock Canyon Wilderness Study Area, Washoe 

County, Nevada D2

2. Map showing mineral resource potential and generalized geology of High Rock Canyon 

Wilderness Study Area, Washoe County, Nevada 4

3. Map showing gravity contours of High Rock Canyon Wilderness Study Area, Washoe 

County, Nevada 8

Contents V

MINERAL RESOURCES OF WILDERNESS STUDY AREAS: 

NORTHWESTERN NEVADA

Mineral Resources of the

High Rock Canyon Wilderness Study Area,

Washoe County, Nevada

By Brent D. Turrin, Joel R. Bergquist, Robert L. Turner, 

and Donald Plouff 

U.S. Geological Survey

Carl W. Ponader 

Stanford University

Douglas F. Scott 

U.S. Bureau of Mines

SUMMARY

Abstract

The High Rock Canyon Wilderness Study Area (CA-020- 

913 B), located 40 mi north of Gerlach, Nev., and 25 mi southsoutheast of Vya, Nev., encompasses approximately 33,300 

acres. The U.S. Bureau of Land Management requested mineral 

surveys on 11,980 acres of the High Rock Canyon Wilderness 

Study Area. In this report, references to the "High Rock Canyon 

Wilderness Study Area" or "study area" refer only to the lands on 

which the U.S. Bureau of Land Management requested surveys.

Geologic, geochemical, geophysical, and mineral surveys of the wilderness study area were conducted by the U.S. 

Geological Survey and U.S. Bureau of Mines between 1985 and 

1986 to evaluate the identified (known) mineral resources and 

to assess the mineral resource potential (undiscovered). There 

are no identified mineral resources in the study area. However, 

these studies indicate that parts of the study area have a high 

potential for zeolite mineral resources in altered tuffaceous 

sediments, a moderate resource potential for gold, silver, and 

mercury in epithermal-type precious-metal deposits, and a low 

potential for uranium, lithium, geothermal energy, oil, and gas 

resources. There is a low resource potential for zeolite in the 

southern part of the area. Presently, there are no miningdistricts, 

mines, current claims, gas or geothermal leases, or mineral 

resource production in the study area.

Character and Setting

The High Rock Canyon Wilderness Study Area (CA020-913B) is situated in the transition zone between the Basin 

and Range and Columbia Plateau physiographic provinces. 

The Basin and Range Province is an extensive semi-arid to 

arid tract of subparallel, north-trending en echelon mountain 

ranges and intervening valleys. The Columbia Plateau Province is a high dissected plateau composed mostly of Tertiary 

volcanic rocks. The 11,980-acre study area, located in the 

Calico Mountains, eastern Washoe County, Nev., 40 mi north 

of Gerlach and 25 mi south-southeast of Vya, comprises a 1- 

to 2-mile-wide strip along the southwestern rim of High Rock 

Canyon (fig. 1). Elevations range from 5,000 ft at the canyon 

bottom to over 6,000 ft on the canyon rim. The canyon walls 

are steep and subparallel to the regional tectonic structure. 

The area is underlain by a sequence of Tertiary rhyolitic to 

dacitic ash-flow tuffs and flows (see Geologic time chart in 

appendixes for age definitions). Two major sets of faults that 

trend northwest and northeast occur within the study area.

Identified Resources

There are no identified resources within or adjacent to 

the study area. However, altered tuffs in the Yellow Rock 

Canyon area (fig. 2) contain as much as 80 percent

Mineral Resources of the High Rock Canyon Wilderness Study Area, Washoe County, Nevada D1
42°

1 20°00' 1 19°45' 119°00'

LAKE CO 

WASHOE CO HUMBOLDT CO

SUMMIT LAKE 

INDIAN RESERVATION!

APPROXIMATE BOUNDARY 

OF

HIGH ROCK CANYON 

WILDERNESS STUDY 

AREA (CA-020-913B) ,'

Soldier Meadow 

KGRA

Double 

Hot Springs 

KGRAV

AREA OF AAAP 

41°00' I

Figure 1. Index map showing location of High Rock Canyon Wilderness Study Area, Washoe County, Nevada.

D2 Mineral Resources of Wilderness Study Areas: Northwestern Nevada
clinoptilolite (zeolite). These clinoptilolite deposits are not 

currently classified as a resource by the U.S. Bureau of Mines. 

Four mining districts are located near the study area; 

the Leadville silver district, approximately 20 mi south of the 

study area; the Lone Pine mercury-gold district, approximately 35 mi north-northeast of High Rock Canyon; and the 

Leonard Creek and Varyville gold mining districts, approximately 30 mi northeast of the study area. In addition, small 

perlite, diatomite, and uranium prospects are found 10 to 20 

mi southwest of the study area.

Mineral Resource Potential

The Calico Mountains are part of a regional area that is 

characterized by extensive exposures of Tertiary volcanic 

rocks that are locally hydrothermally altered and silicified. In 

this region, hydrothermally altered rocks may host deposits of 

precious metals (gold and silver) and industrial minerals. In 

the Yellow Rock Canyon vicinity of the study area there is a 

high mineral resource potential for zeolite, in the form of 

clinoptilolite, and a moderate resource potential for epithermal-type gold, silver, and mercury deposits (fig. 2). There is 

also a moderate resource potential for epithermal-type gold, 

silver, and mercury deposits and a low resource potential for 

zeolite near the southern tip of the study area. In addition, 

there is a low resource potential for uranium, lithium, geothermal, oil, and gas resources throughout the entire study area.

potential and certainty of assessment and for the resource/ 

reserve classification.

The climate is semiarid to arid, dominated by continental tropical air masses in summer and continental polar air 

masses in winter, typical of a middle-latitude desert climate 

(Sthraler, 1969, and Houghton and others, 1975). Annual 

temperatures range from less than -4 °F in winter to more than 

100 °F during the summer. Daily summer temperature 

changes frequently exceed 50 °F. Precipitation ranges from 5 

to 15 in. annually, mostly as snow and winter rain. During 

summer, relative humidity averages about 20 percent but may 

fall to 10 percent.

Several varieties of sagebrushes and grasses cover 

most of the area. Willow, cottonwood, and aspen occur along 

drainages.

Wildlife in the area includes pronghorn antelope, deer, 

coyote, bobcat, mountain lion, and a variety of smaller 

mammals. Feral horses and burros are also abundant. The 

avian population varies seasonally in numbers and species.

Most parts of the study area are accessible via unimproved roads from Nevada State Highway 34. The study area 

can also be accessed from the north via Nevada S tate Road 8 A. 

These roads pass through High Rock Canyon along the 

northeast boundary of the study area, following the historic 

Lassen-Applegate Trail of the mid-1800's. An unimproved 

road borders the southwest part of the study area. However, 

these roads are subject to periodic washouts and in places may 

only be passable to high-clearance four-wheel-drive vehicles.

INTRODUCTION

The High Rock Canyon Wilderness Study Area, (CA020-913B) comprises approximately 11,980 acres in the 

Calico Mountains, eastern Washoe County, Nev. A mineral 

resource survey of the study area was conducted in the spring 

of 1985. This mineral survey was requested by the U.S. 

Bureau of Land Management (BLM) and is a joint effort by 

the U.S. Geological Survey (USGS) and U.S. Bureau of 

Mines (USBM).

Identified resources and known mineralized areas are 

evaluated by the USBM by collecting data on current and past 

mining activities and through field examination of known 

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 USGS are designed to provide a reasonable scientific basis to assess the potential for undiscovered 

mineral resources within the wilderness study area. Field 

mapping of geologic units and structures, geochemical sampling, and geophysical studies were performed to provide the 

necessary data to evaluate, with respect to known ore-deposit 

models, the mineral resource potential of the study area. 

Mineral assessment methodology and terminology as they 

apply to these surveys are given in Goudarzi (1984). See 

appendixes for the definition of levels of mineral resource

APPRAISAL OF IDENTIFIED RESOURCES

By Douglas F. Scott 

U.S. Bureau of Mines

Methods and Scope of Investigation

U. S. Bureau of Mines personnel gathered data concerning mines, claims, prospects, and mineralized areas from 

BLM records, published literature, USBM files and production records, and county mining records. Field work was 

conducted during June and July 1985 and consisted of ground 

and helicopter reconnaissance and an examination of all 

known claims and prospects in or near the study area.

Twenty-six lode samples and seven placer samples 

were collected within or adjacent to the study area and 

analyzed for gold, silver, and numerous metallic elements. In 

addition, samples were measured for radioactivity and fluorescence. Quantitative concentrations of gold and silver were 

determined by fire assay; concentrations for other elements 

were determined by atomic absorption or inductively coupled 

plasma analysis. In addition, at least one sample from each 

prospect, claim, or mineralized area was analyzed for 40 

elements by semiquantitative spectrographic methods (including antimony, barium, cadmium, cobalt, chromium, 

copper, gold, iron, lead, lithium, magnesium, manganese,

Mineral Resources of the High Rock Canyon Wilderness Study Area, Washoe County, Nevada D3
119°27'30" 119° 25' 119°22'30" 119° 20' 1190 17'30"

41°27'30'

41°25'

41°22'30

41° 20'

41°17'30

EXPLANATION

Area with high mineral resource potential 

Area with moderate mineral resource potential 

Area with low mineral resource potential

APPROXIMATE BOUNDARY 

OF

See appendix for definition of levels of mineral resource 

HIGH ROCK CANYON potential (H,M,L) and certainty of assessment (B,C,D)

WILDERNESS STUDY AREA

(CA-020-913B) Commodities 

Gold 

Silver 

Geo thermal 

Mercury

Lithium 

Oil and Gas 

Uranium 

Zeolite

M/CAu,Ag,Hg[ll 

H/DZeo[I] Deposit type

Volcanigenic hydro- and epithermal 

deposits hosted in volcanic and volcaniclastic rocks

Alluvium (Holocene)

Landslide deposits (Holocene)

Andesite to dacite flows and 

dikes(Miocene)

Tuffaceous sediments, includes 

lacustrine sedimentary rocks, airfall tuffs, and water-reworked ash 

(Miocene)

Rhyolite flows, domes, and dikes 

(Miocene)

Rhyolitic intrusive rocks and dikes 

(Miocene)

Contact-Dashed where approximate 

Normal fault-Dashed where approximate; dotted where concealed; bar 

and ball on down-thrown side

Correlation of map units

L/B Geo 

L/D O, G

L/C U[l] 

(entire study

area) 

Qal

M/CAu,Ag,Hg[l] 

L/BZeoflJ

Figure 2. Mineral resource potential and generalized geologic map of High Rock Canyon Wilderness Study Area, 

Washoe County, Nevada.

D4 Mineral Resources of Wilderness Study Areas: Northwestern Nevada
molybdenum, nickel, platinum, silver, tin, titanium, vanadium, and zinc). Samples of altered tuffaceous sediments 

were examined microscopically and by X-ray diffraction for 

clay and zeolite minerals. The results of these analyses are 

summarized in Scott (1987). Additional information concerning the study area and copies of the Mineral Land Assessment report are available from the U.S. Bureau of Mines, 

Western Field Operations Center, E. 360 Third Avenue, 

Spokane, WA 99202.

Major mining companies were exploring (1984) for 

disseminated gold-silver-mercury deposits north, south, and 

west of the area. Forty-four gold-silver-mercury claims (GRE 

claims) were maintained by Tennecoin 1984. Mercury occurs 

in cinnabar in massive opal and opalized breccia. Concentrations of mercury from two samples were 120.0 and 330.0ppm. 

Concentrations of gold and silver were low; however, similarities between geologic features in the study area and those 

associated with known disseminated gold, silver,and mercury 

deposits indicate company interest may continue near and into 

the northwest part of the area.

History of Mining and Mineral Exploration

No mining districts, current claims, oil, gas, or geothermal leases or production are known in the area.

In 1911, six placer claims were located in High Rock 

Canyon (adjacent to east edge of area) from the confluence of 

Mahogany Creek and extending north for about 1 mi. Seven 

placer samples collected from these abandoned placer claims 

contained gold values ranging from zero to $0.06 per cubic 

yard (gold valued at $400/troy ounce).

One prospect trench in the southeast part of the study 

area is about 50 ft long, 12 ft wide, and 6 ft deep. The trench 

is along a fault zone that strikes N. 65° E. and dips vertically 

in ash-flow tuff. The zone is filled with green, fractured, and 

opalized breccia, averages 35 ft thick, and crops out discontinuouslyforatleast200ft. Six samples were taken. Three 

chip samples of opalized breccia contained no detectable 

gold, silver, arsenic, or mercury, and one sample of opal 

contained no gold, silver, or mercury and 72.0 ppm arsenic. 

Two random samples of ash-flow tuff contained 50.0 and 56.0 

percent zeolite (clinoptilolite).

Zeolites occur in varying concentrations in ash-flow 

tuff in Yellow Rock Canyon and lower Mahogany Creek. 

Within the study area, seven samples of ash-flow tuff contained from 50 to 65 percent clinoptilolite. Two samples of 

discolored ash-flow tuff, adjacent to the area, contained 65.0 

and 80.0 percent clinoptilolite. The basal part of the ash-flow 

tuff was not exposed; therefore, thickness of the tuff is 

unknown. In the study area, ash-flow tuff outcrops are several 

hundred feet thick and occur discontinuously in an area of 

about 6 square miles. Several hundred million tons of ashflow tuff occur in the area, and zeolites were found at several 

locations. Reconnaissance samples of ash-flow tuff were 

random and less than 50 ft in length.

Near Grassy Canyon, a 3.5-ft-thick fracture in basalt is 

filled with brown cryptocrystalline quartz and fractured and 

dark-colored opal. The samples contained no detectable gold 

or silver.

About 4 mi west from the area are 28 opal claims 

known as the SPDY claims. Fractures in ash-flow tuff are 

filled with massive white-to-green opal. The opal is fractured 

and massive and not of gem quality.

Identified Resources

No mineral resources were identified in or adjacent to 

the High Rock Canyon study area.

Massive opal, opalized breccia, ash-flow tuff, and 

mercury in opal exist in several known disseminated gold, 

silver, and mercury deposits. These geologic conditions occur 

in and near the north, south, and west parts of the area. Bureau 

of Mines samples adjacent to the northwest part of the area 

indicated as much as 120.00 and 330.0 ppm mercury in opal 

and opalized breccia. Although no resources were identified, 

continued mining company exploration near the area, especially in or near the north, south, and west parts of the area, is 

expected.

Zeolite resources were not estimated because of

(1) low concentrations of sampled zeolite,

(2) unknown areal extent of zeolite-bearing tuff,

(3) unknown thickness of zeolite-bearing tuff,

(4) incomplete identification of zeolite-bearing tuff 

outcrops,

(5) current low market demand for zeolite,

(6) difficulty in field identification of zeolite-bearing 

tuffs, and

(7) absence of proximal mills.

Further exploration may define the extent and concentration 

of zeolites in tuff; however, because adequate deposits of 

higher and more consistent grade are proximal to existing 

mills and because market demands for zeolites are low, 

interest by mining companies should be minor now and in the 

foreseeable future.

Opal in the study area is massive, dark colored, and 

fractured and therefore not of gem quality. Future interest by 

gem collectors for opal should be minor.

Placer-gold exploration is not expected due to very low 

concentrations of gold in the alluvium sampled.

Sand and gravel occur in small amounts sporadically in 

the area. Because sand and gravel outside the area are 

adequate for present market demands, sand and gravel in the 

area do not constitute a resource.

Mineral Resources of the High Rock Canyon Wilderness Study Area, Washoe County, Nevada D5
ASSESSMENT OF MINERAL RESOURCE POTENTIAL

By Brent D. Turrin, Joel R. Bergquist, Robert L. Turner, and

Donald Plouff,

U.S. Geological Survey

Carl W. Ponader 

Stanford University

Geology

The High Rock Canyon Wilderness Study Area is 

underlain by Tertiary volcanic flows and volcaniclastic sediments (fig. 2). Although the basal contact of the Tertiary 

section is not exposed, local relief indicates that the volcanic 

section is more than 1,000 ft thick. The major fault trends 

within the study area, northwest and northeast, are typical of 

this part of the Basin and Range Province.

The oldest geologic unit exposed in the study area has 

been called the Canon Rhyelite of Merriam (1910) by 

Bonham (1969). This unit, composed of rhyolite flows, 

domes, and subordinate intercalated pyroclastic deposits, is 

Miocene in age. Potassium-argon (K-Ar) ages of 15 Ma 

(million years ago) are reported in Noble and others (1970) 

and Harvey and others (1986). Commonly, the unit is light 

purplish gray to reddish brown, microcrystalline to finegrained rock containing fractured phenocrysts of alkali feldspar, quartz, and rare euhedral to subhedral biotite and alkali 

amphibole. Flow banding, flow foliations, and ramp structures are common features of the Canon Rhyolite. The rocks 

are peralkaline in composition, as are most rhyolitic tuffs and 

lavas of middle Miocene age in the region (Noble and others, 

1968; Noble and others, 1970; Korringa, 1973; Bonham, 

1969; and Harvey and others, 1986).

Interbedded with and unconformably overlying the 

Canon Rhyolite is a sequence of ash-flow tuffs, tuffaceous 

sediments, and dacitic to andesitic flow rocks informally 

referred to as the High Rock sequence by Bonham (1969). 

This unit has been subdivided into two subunits within the 

study area: a gray-green tuffaceous sedimentary unit that 

consists primarily of air-fall tuff, and a unit consisting of 

dacitic to andesitic flow rocks. Dacite-andesite flows are 

interbedded with the tuffaceous sedimentary rocks. Locally, 

the High Rock sequence contains welded air-fall tuff, ashflow tuff, and water-worked tuffaceous sediments.

Two known mining districts near the study area have 

similar geologic environments. The Leadville District, approximately 20 mi south of the study area, is the largest 

producer of lead and silver in Washoe County. Production 

started in 1910 and continued intermittently until 1928 

(Bonham, 1969). The Hog Ranch mine, located near the 

Leadville District began production in October 1986. Estimated reserves of approximately 5 million tons of heapleachable gold ore have been reported (Anonymous, 1986).

The Lone Pine District is approximately 35 mi northnortheast of High Rock Canyon. Gold and silver prospecting

occurred there between 1897 and 1909, although no gold or 

silver production was reported. However, mercury was discovered in 1929, and a small amount was produced. The 

district has been idle since 1955 (Tuchek and others, 1984). 

Small perlite, diatomite, and uranium prospects are 

present 10 to 20 mi southwest of the study area. For a complete 

discussion of the surrounding mining districts in Washoe 

County and Humboldt County, see Bonham (1969) and 

Willden (1964), respectively.

Geochemistry

As part of a reconnaissance geochemical survey of the 

High Rock Canyon Wilderness Study Area, 69 stream-sediment samples were collected, of which 24 are from within the 

study area. The minus-80-mesh-size fraction of stream-sediment and heavy-mineral-concentrate samples were collected 

from alluvium in stream channels. A complete description of 

the sampling and analytical techniques is given in Adrian and 

others (1987).

Geochemical samples were analyzed for 31 elements 

by six-step semiquantitative emission-spectrographic methods (Myers and others, 1961 and Grimes and Marranzino, 

1968). Additional analyses were by atomic-absorption spectroscopy and inductively coupled argon-plasma atomic-emission spectroscopy. These analytical data are used to identify 

drainages that have anomalously high concentrations of 

metallic elements. Geochemical concentrations are considered anomalous if they are greater than one standard deviation 

above mean background values.

Some of the stream-sediment samples from the Yellow 

Rock Canyon drainage are anomalous in arsenic, antimony, 

mercury, and cadmium. In addition, some of the heavymineral concentrates from the study area show anomalous 

concentrations of arsenic, antimony, and mercury; one sample 

contained detectable gold. Geochemical anomalies of arsenic, antimony, mercury, and cadmium are often associated 

with volcanic-hosted epithermal-type gold-silver deposits 

(Berger, 1986) and may suggest mineral resource potential.

Geophysics

Geophysical data used in the evaluation of the mineral 

resource potential consist of aerial gamma-ray spectroscopy, 

aeromagnetic, and gravity surveys.

Gamma-ray Spectroscopy

Radiometric data for the area were compiled by Geodata International Incorporated (1979) for the Department of 

Energy National Uranium Resource Evaluation (NURE) 

program. The gamma-ray flux survey consists of three eastwest flightlines on 3-mi centers at an altitude of 300 to 700 ft

D6 Mineral Resources of Wilderness Study Areas: Northwestern Nevada
above mean ground level. Gamma-ray fluxes from the radioactive isotopes of uranium, thorium, and potassium were 

recorded for the gamma-ray flux survey.

Gamma-ray flux levels for potassium, uranium, and 

thorium in the study area are about the same as in the 

surrounding terrain. The gamma-ray flux levels for uranium 

and thorium are slightly higher along the northern flight line, 

which was flown over late Miocene sedimentary rocks, approximately 2 mi south of the northern boundary of the study 

area. Uranium anomalies have been reported from fractured 

pieces of petrified wood found in these sediments (Garside, 

1973). Uranium minerals in Tertiary sedimentary rocks often 

occur as encrustations or disseminated flakes along bedding 

planes or iron-stained fractures (Garside, 1973). These 

radiometric data do not indicate significant uranium or thorium occurrences.

Aeromagnetic Survey

An aeromagnetic survey was conducted as part of the 

mineral resource evaluation of the study area (U.S. Geological 

Survey, 1985). North-south flight lines, spaced at 0.5-mi 

centers, were flown at an altitude of about 1,000 ft above mean 

ground level.

Five roughly circular magnetic lows 1 to 2 mi in 

diameter are scattered throughout and along the southeast 

boundary of the study area. An inverse correlation between 

magnetic anomalies and topography indicates that source 

rocks for the magnetic lows are reversely magnetized and are 

at or near the surface. For example, magnetic lows overlie 

hilltops and magnetic highs commonly overlie canyons. 

However, one conspicuous magnetic low overlies an area of 

rhyolitic intrusives exposed in the Yellow Rock Canyon area. 

This magnetic low probably defines a Tertiary intrusive 

complex.

Gravity Survey

The wilderness study area is located along the southwestern flank of a conspicuous gravity low centered approximately 3 to 4 mi northeast of the study area (fig. 3). The 

gravity low is the southernmost part of a regional gravity low 

approximately 12 by 30 mi in size. Plouff (1984) interpreted 

this gravity low as a buried caldera. Presumably, the gravity 

low is present because of the accumulation of relatively lowdensity tuffaceous sedimentary rocks within the caldera depression.

Mineral Resource Potential

The mineral resource potential for the High Rock 

Wilderness Study Area is classified using the system of 

Taylor and Steven (1983), Taylor and others (1984); and

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

of mineral resource potential and certainty of assessment and 

for the resource/reserve classification.

A large volume of altered (zeolitized) tuff occurs in the 

Yellow Rock Canyon area. These altered tuffs contain as 

much as 80 percent zeolite (clinoptilolite). The basal part of 

the ash-flow tuff was not exposed; therefore, thickness of the 

tuff is unknown. In the study area, however, the zeolitebearing ash-flow tuff outcrops are as much as 400 ft thick and 

occur discontinuously in an area of about 6 mi2. This indicates 

that several hundred million tons of ash-flow tuff occur in the 

Yellow Rock Canyon area. On the basis of these data, surface 

relief, and aerial extent of the zeolite-bearing material in the 

Yellow Rock Canyon area, there is a high resource potential, 

certainty level D, for approximately 13 million to 1.3 billion 

yd3 of zeolite-bearing material (clinoptilolite) at a grade of 

approximately 50 to 80 percent clinoptilolite in the study area. 

An exchange capability of 1.2 milliequi valents/gram has been 

reported for zeolite occurrences in the High Rock Lake 

Wilderness Study Area (NV-020-007), approximately 5 mi 

east-southeast of this study area (Neumann and Close, 1985).

The study area has a moderate resource potential for 

mercury, gold, and silver in epithermal-type deposits, certainty level C. Zeolite-bearing rocks and the anomalous 

concentrations of mercury, arsenic, antimony, and molybdenum found in the Yellow Rock Canyon area indicate that 

hydrothermal systems have been active in the past. Moreover, 

an epithermal-type gold deposit at the Hog Ranch mine, 

located approximately 15 mi south of the study area, indicates 

that hydrothermal mineralization has occurred in the region. 

Ring-fracture structures along the postulated caldera of Plouff 

(1984) could have provided conduits for hydrothermal fluids.

At McDermitt, Nev., about 60 mi to the east-northeast, 

a caldera is the site of uranium and extensive mercury deposits 

(Rytuba, 1975). In addition, lithium occurrences are also 

found in zones of zeolitization at McDermitt, Nev. (Rytuba 

andGlanzman, 1979). This evidence suggests a low resource 

potential for lithium, certainty level B, for the High Rock 

Canyon study area. There is also a moderate resource potential for epithermal-type gold, silver, and mercury deposits, 

certainty level C, and a low resource potential for zeolite, 

certainty level B, near the southern tip of the study area.

The High Rock Canyon study area has a low resource 

potential for uranium, certainty level C, as suggested by the 

geochemical and radiometric data. Only four uranium prospects have been reported from northern Washoe County 

(Garside, 1973).

Oil and gas resource potential for the study area is low, 

certainty level D. Because of the extensive Miocene volcanic 

activity, the area is too thermally mature to have formed any 

hydrocarbon reserves (Sandberg, 1983).

There are no known geothermal production leases or 

hot springs within the study area. However, the Soldier 

Meadow KGRA (Known Geothermal Resource Area) and the 

Double Hot Springs KGRA are within 5 and 18 mi, 

respectively. Given the lack of field evidence for the

Mineral Resources of the High Rock Canyon Wilderness Study Area, Washoe County, Nevada D7
119= 22'30" 119°17'30"

41°27'30"

41°22'30" -

4ri7'30" -

APPROXIMATE BOUNDARY

OF 

HIGH ROCK CANYON

WILDERNESS STUDY AREA

(CA-020-913B)

Figure 3. Gravity-contour map of High Rock Canyon Wilderness Study Area, Washoe County, Nevada. Values in 

gammas; contour interval 2 gammas; hachured in direction of gravity low.

D8 Mineral Resources of Wilderness Study Areas: Northwestern Nevada
necessary hydrologic conditions to form hot springs within 

the High Rock Canyon study area, the geothermal resource 

potential for the study area is low, certainty level B.

REFERENCES CITED

Adrian, B.M., Tunner, R.L., Malcolm, M.J., Fey, D.L, Crock, 

J.G., and Delaney, T.A., 1987, Analytical results and 

sample locality map of stream-sediment, heavy-mineralconcentrate and rock samples from the Rough Hills 

Wilderness Study Area, Elko County, Nevada, (NV-010- 

151): U.S. Geological Survey Open-File Report 87-431, 

12 p.

Anonymous, 1986, Hog Ranch gold discovery first in northern 

Washoe County: Nevada Mining Association Bulletin, 

February-March, p. 20-21.

Berger, B.R., 1986, Descriptive model of hot-spring Au-Ag in 

Cox, D.P., and Singer, D.A., eds., Mineral deposit models: 

U.S. Geological Survey Bulletin 1693, 379 p.

Bonham, H.F., 1969, Geology and mineral deposits of Washoe 

and Storey Counties, Nevada, with a section on industrial 

minerals by K. G. Papke: Nevada Bureau of Mines and 

Geology Bulletin 70, 140 p.

Garside, L.J., 1973, Radioactive mineral occurrences in Nevada: Nevada Bureau of Mines and Geology Bulletin 81, 

121 p.

Geodata International, Inc., 1979, Aerial radiometric and 

magnetic survey national topographic map, Vya, Nevada: U.S. Departmentof Energy Open-File ReportGJBX136 (79), v. 2, 73 p.,scale 1:125,000.

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

Survey Open-File Report 84-0787, 51 p.

Harvey, S.D., Noble, D.C., and McKee, E.H., 1986, Hog Ranch 

gold property, northwestern Nevada: age and genetic 

relation of hydrothermal mineralization to coeval peralkaline silicic and associated basaltic magmatism: Isochron/West, no. 47, p. 9-11.

Houghton, J.G., Sakamoto, C.M., and Gifford, R.O., 1975, 

Nevada's weather and climate: Nevada Bureau of Mines 

and Geology Special Publication 2, 78 p.

Korringa, M.K., 1973, Linear vent area of the Soldier Meadow 

Tuff, an ash-flowsheet in northwestern Nevada: Geological Society of America Bulletin, v. 84, p. 3849-3866.

Merriam, J.C., 1910, Tertiary mammal beds of Virgin Valley and 

Thousand Creek, in northwestern Nevada; Part I, Geologic history: Berkeley, University of California, Department of Geology Bulletin, v. 6, no. 2, p. 21 -53.

Neumann, T.R., and Close, T.J., 1985, Mineral resources of the 

High Rock Lake Wilderness Study Area (BLM No. NV020-007), Humboldt County, Nevada: U.S. Bureau of 

Mines Open-File Report 38-85, 13 p.

Noble, D.C., Chipman, D.W., and Giles, D.L., 1968, Peralkaline silicic volcanic rocks in northwestern Nevada: Science^. 160, p. 1337-1338.

Noble, D.C., McKee, E.H., Smith, J.R., and Korringa, M.K., 

1970, Stratigraphy and geochronology of Miocene volcanic rocks in northwestern Nevada, in U.S. Geological 

Survey Research 1970: U. S. Geological Survey Professional Paper 700-D, p. D23-D32.

Plouff, Donald, 1984, Interpretation of aeromagneticand gravity data, Charles Sheldon Wi Iderness Study Area, Nevada 

and Oregon: U.S. Geological Survey Bulletin 1538-B, p. 

35-50, pi. 2, scale 1:125,000.

Rytuba, J.J., 1976, Geology and ore deposits of the McDermitt 

caldera, Nevada-Oregon: U.S. Geological SurveyOpenFile Report 76-535, 9 p.

Rytuba, J.J., and Glanzman, R.K., 1979, Relation of mercury, 

uranium, and lithium deposits to the McDermitt caldera 

complex, Nevada-Oregon: Nevada Bureau of Mines and 

Geology Report 33, p. 109-117.

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

in Nevada: U.S. Geological Survey Circular 902-H, p. 

H1-H11.

Scott, D.F., 1987, Mineral resources of the High Rock Canyon 

Wilderness Study Area, Washoe County, Nevada: U.S. 

Bureau of Mines Mineral Land Assessment Open-File 

Report 14-87, 18 p.

Sthraler, A.,1969, Physical geography: New York, John Wiley 

and Sons, Inc., p.219-238. [Condensed by Wladimir 

Koppen, from Die Klimate der Erde: Grundriss der 

Klimakunde, Berlin, Walter de Gruyter Co., 369 p.]

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, 42 p.

Tuchek, E.T., Johnson, F.J., and Conyac, M.D., 1984, Economic 

appraisal of the Charles Sheldon Wilderness Study Area, 

in Mineral resources of the Charles Sheldon Wilderness 

Study Area, Humboldt and Washoe Counties, Nevada, 

and Lake and Harney Counties, Oregon: U.S. Geological 

Survey Bulletin 1538-D, p. D89-D139.

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U.S. Geological Survey Circular 831, 5 p.

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Rock Lake area, northwestern Nevada: U.S. Geological 

Survey Open-File Report 85-751,1 sheet, scale 1:62500.

Willden, Ronald, 1964, Geology and mineral deposits of 

Humboldt County, Nevada: Nevada Bureau of Mines and 

Geology Bulletin 59, 154 p.

Mineral Resources of the High Rock Canyon Wilderness Study Area, Washoe County, Nevada D9

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 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

t

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 84-0787, p. 7, 8.

D12 Mineral Resources of Wilderness Study Areas: Northwestern Nevada
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

I

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.

Mineral Resources of the High Rock Canyon Wilderness Study Area, Washoe County, Nevada D13
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

\j

- 24

 'JQ

\j\j 

cc

- 96

1 OO

one

£.*T\J

£~\J\J 

**l**lf\

- ~330

_ oen

- 410

^\J\J

- 500

\J i \J

- 900

- 1600 

- 2500

- 3000

otv/w

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

Informal time term without specific rank.

D14 Mineral Resources of Wilderness Study Areas: Northwestern Nevada

GPO 585-045/78036