Mineral Resources of the 

Camp Creek and Cottonwood Creek 

Wi Iderness Study Areas, 

Malheur County, Oregon

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Chapter C

Mineral Resources of the

Camp Creek and Cottonwood Creek

Wilderness Study Areas,

Malheur County, Oregon

By WILLIAM J. KEITH, ROBERT L. TURNER, and 

ANDREW GRISCOM 

U.S. Geological Survey

JOHN R. BENHAM and MICHAEL S. MILLER 

U.S. Bureau of Mines

U.S. GEOLOGICAL SURVEY BULLETIN 1741

MINERAL RESOURCES OF WILDERNESS STUDY AREAS: 

EAST-CENTRAL OREGON
DEPARTMENT OF THE INTERIOR 

MANUEL LUJAN, JR., Secretary

U.S. GEOLOGICAL SURVEY 

Dallas L. Peck, Director

Any .use of trade, product, or firm names

in this publication is for descriptive purposes only

and does not imply endorsement by the U.S. Government

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1989

For sale by the

Books and Open-File Reports Section

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Library of Congress Cataloging-in-Publication Data

Mineral resources of the Camp Creek and Cottonwood Creek Wilderness Study

Areas, Malheur County, Oregon / by William J. Keith . . . [et al.]

p. cm. (Mineral resoources of wilderness study areas eastcentral Oregon ; ch. C)(U.S. Geological Survey bulletin ; 1741-C)

Bibliography: p.

Supt. of Docs. no. : I 19.3:1741-C

1. Mines and mineral resources Oregon Camp Creek Wilderness.

2. Mines and mineral resources Oregon Cottonwood Creek Wilderness.

3. Camp Creek Wilderness (Or.) 4. Cottonwood Creek Wilderness (Or.) 

I. Keith, William J., 1933- II. Series. 111. Series: U.S. Geological Survey 

bulletin; 1741-C.

QE75.B9 no. 1741-C 557.3s dc20 89-600218 

UN24.07] [5S3'.09795I 97] CIP
STUDIES RELATED TO WILDERNESS

Bureau of Land Management Wilderness Study Area

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 of 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 Camp 

Creek (OR-003-031) and Cottonwood Creek (OR-003-032) Wilderness Study Areas, 

Malheur County, Oregon.

CONTENTS

Summary Cl

Abstract Cl

Character and setting Cl

Identified resources Cl

Mineral resource potential C3 

Introduction C3

Area description C3

Previous and present investigations C3

Acknowledgments C5 

Appraisal of identified resources C5

Mining and exploration history C5

Identified resources C5 

Diatomite C5 

Pozzolan C7 

Sand and gravel C8 

Stone (dimension and decorative) C8

Mineral occurrences C8 

Metallic minerals C8 

Nonmetallic materials C8

Recommendations for further work C9 

Assessment of mineral resource potential C9

Geological studies C9

Geochemical studies C9

Geophysical studies CIO

Mineral and energy resource potential Cll 

References cited Cll 

Appendixes

Definition of levels of mineral resource potential and certainty of assessment C14

Resource/reserve classification CIS

Geologic time chart C16

FIGURES

1. Index map showing location of Camp Creek and Cottonwood Creek Wilderness Study 

Areas, Malheur County, Oregon C2

2. Map showing mineral resource potential, generalized geology, and sample sites of 

Camp Creek and Cottonwood Creek Wilderness Study Areas, Malheur County, 

Oregon C4

TABLE

1. Identified mineral resource data for sample sites in and near the Camp Creek and 

Cottonwood Creek Wilderness Study Areas, Malheur County, Oregon C6

Contents

Mineral Resources of the

Camp Creek and Cottonwood Creek

Wilderness Study Areas,

Malheur County, Oregon

By William J. Keith, Robert L. Turner, and Andrew Griscom 

U.S. Geological Survey

John R. Benham and Michael S. Miller 

U.S. Bureau of Mines

SUMMARY

Abstract

The Camp Creek (OR-003-031) and Cottonwood Creek 

(OR-003-032) Wilderness Study Areas are located in the 

Owyhee region of Malheur County, southeastern Oregon. At 

the request of the U.S. Bureau of Land Management, approximately 20,310 acres of the Camp Creek (OR-003-031) and 

7,700 acres of the Cottonwood Creek (OR-003-032) Wilderness Study Areas were studied. In this report, the areas 

studied are referred to as "the wilderness study areas," or 

simply "the study areas." Geological, geochemical, geophysical, and mineral surveys were conducted by the U.S. 

Geological Survey and the U.S. Bureau of Mines in 1986 to 

assess the identified mineral resources (known) and mineral 

resource potential (undiscovered) of the study areas. There 

are no claims or mines, current or historical, in the study 

areas. However, two small pits of unknown origin were 

found on the extreme north boundary of the Camp Creek 

study area. Resources of diatomite, pozzolan (siliceous 

material used in cement), sand and gravel, and building stone 

were identified, and volumes were estimated. Calcite, perlite, 

and metal (antimony, arsenic, barium, gold, molybdenum, 

and tungsten) occurrences were observed in the study areas 

but are too small and low grade to constitute resources. In 

addition, these studies indicate areas of moderate mineral 

resource potential for epithermal-vein-type gold and (or) silver and low mineral resource potential for diatomite in the 

eastern part of both study areas and moderate mineral resource potential for hot-spring-type gold throughout both 

study areas. There is also low mineral resource potential 

throughout both study areas for zeolites, building stone, and 

pozzolan. Both study areas have low potential for hightemperature (194 to 302 °F) geothermal resources and for oil 

and gas resources.

Character and Setting

The Camp Creek and Cottonwood Creek Wilderness 

Study Areas (fig. 1) are in the rugged uplands of southeastern Oregon about 50 mi west of Boise, Idaho. The topography is typical of a deeply dissected plateau and reflects 

the High Lava Plains physiographic subprovince in which 

the study areas are located. Relief in the areas is moderate, 

with elevations ranging from 3,360 ft at the Stringer shearing plant to about 5,320 ft southeast of Monument Peak 

(fig. 2). The study areas contain a nearly horizontal sequence of lava flows, pyroclastic deposits, and associated 

sedimentary rocks of Miocene and Pliocene age (see geologic time chart in "Appendixes"). The rocks are cut by 

high-angle normal faults.

Identified Resources

Approximately 10 million tons of inferred marginal 

reserves of cake diatomite exist in and near the Camp 

Creek study area. It is estimated that inferred marginal 

reserves of pozzolan consist of more than 40 million tons 

in the inferred reserve base1 in the Camp Creek study area 

and more than 10 million tons in the inferred reserve base 

in the Cottonwood Creek study area. Inferred marginal

Manuscript approved for publication, May 10, 1989.

'The in-place part of an identified resource from which inferred 

reserves are estimated. Quantitative estimates are based largely on 

knowledge of the geologic character of a deposit for which there may be 

no samples or measurements. The estimates are based on an assumed 

continuity beyond the reserve base, for which there is geologic evidence 

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

Camp Creek and Cottonwood Creek Wilderness Study Areas, Oregon Cl
118° 00' 

44° 00'

117° 45' 1170 30'

43° 45'

43° SOAPPROXIMATE BOUNDARY 

OF

CAMP CREEK

WILDERNESS

STUDY AREA

(OR-003-031)

Monument )'

»

\ 

\ 

APPROXIMATE BOUNDARY

OF

COTTONWOOD CREEK 

WILDERNESS 

STUDY AREA 

(OR-003-032) r-

/ . Freezeout 

7 Mtn

/

/

\ 

\

L

5 MILES

j__i_____\ AREA OF AAAP

Figure 1. Index map showing location of Camp Creek and Cottonwood Creek Wilderness Study Areas, Malheur County, 

Oregon.

C2 Mineral Resources of Wilderness Study Areas: East-Central Oregon
reserves for sand and gravel include a minimum of 2.5 

million cubic yards in the Camp Creek study area and at 

least 2.5 million cubic yards in the Cottonwood Creek 

study area. In and adjacent to the Cottonwood Creek study 

area there are at least 740,000 tons of inferred marginal 

reserves of slab rock suitable for building stone. Perlite 

and calcite occurrences in the Camp Creek study area are 

not economic. Samples of silicified breccia from the 

Shearing Plant fault in the Camp Creek study area, from 

opalized rhyolite breccia northeast of the Gugle Ranch in 

the Cottonwood Creek study area, and from limonitic tuffs 

in the Camp Creek study area contain minor amounts of 

metals.

No oil and gas or geothermal leases exist in the area, 

and no energy resources were identified.

Mineral Resource Potential

The area along the Shearing Plant fault in both study 

areas has moderate mineral resource potential for a small 

epithermal gold and (or) silver deposit (fig. 2) as indicated 

by low-level geochemical anomalies, minor alteration, and 

the presence of quartz stringers and silicified joints associated with the fault. The mineral resource potential across 

both study areas is moderate for hot-spring-type gold deposits, as indicated by the opalized areas and relatively high 

heat flow.

Two areas in the northeastern part of the Camp Creek 

study area and two in the eastern part of the Cottonwood 

Creek study area have low potential for a viable diatomite 

deposit related to lacustrine sediments. Both study areas 

also have low mineral resource potential for zeolite deposits, as indicated by favorable host-rocks, and for building 

stone and pozzolan because both areas are underlain by 

rocks that could contain these materials.

Relatively high heat flow and the presence of hightemperature hydrothermal systems within 50 mi of the 

study areas suggest low potential for high-temperature (194 

to 302 °F) geothermal energy resources in both study areas.

Both study areas also have low potential for oil and gas 

resources. Source beds that may underlie or be interstratified with older rocks exposed in this area could contain oil 

and gas.

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 

was provided by Beikman and others (1983). 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 a 

system that is a modification of that described by McKelvey (1972) and U.S. Bureau of Mines and U.S. Geological Survey (1980). U.S. Geological Survey studies are 

designed to provide a 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. Goudarzi (1984) discussed mineral assessment methodology 

and terminology as they apply to these surveys. See 

"Appendixes" for the definition of levels of mineral resource potential and certainty of assessment and for the 

resource/reserve classification.

Area Description

At the request of the U.S. Bureau of Land Management, approximately 20,310 acres of the Camp Creek 

(OR-003-031) and 7,700 acres of the Cottonwood Creek 

(OR-003-032) Wilderness Study Areas were studied. The 

two study areas join along a section of Cottonwood Creek 

in a sparsely vegetated, plateau-type terrain in northern 

Malheur County, Oreg. (fig. 1). The Union Pacific Railroad and U.S. Highway 20 cross the region about 5 mi 

north of the study areas, which are accessible from all sides 

by unmaintained jeep trails. The interior is accessible only 

by helicopter or horseback or on foot. Elevations range 

from 3,360 ft at the Stringer shearing plant to about 5,320 

ft southeast of Monument Peak (fig. 2).

Previous and Present Investigations

The geologic map (fig. 2) is based on published and 

unpublished geologic maps of Hagood (1963a) and Kittleman and others (1967). Studies by Kittleman and others 

(1965) and Mathews and Blackburn (1983) also provided 

geologic data for this report.

Geochemical data were obtained from analyses of 

stream-sediment samples collected by the U.S. Geological 

Survey (Jones and others, 1988) from streams draining the 

study areas. Bedrock samples were also collected and 

analyzed as a means of obtaining background and alteration 

data.

Geophysical data consist of aeromagnetic surveys by 

the Geophysics Group at Oregon State University (Boler, 

1978) and geoMetrics, Inc. (1979) as well as gravity data 

from a study by Lillie (1977). Aerial gamma-ray spectrometer data are also available from geoMetrics, Inc. 

(1979).

The U.S. Bureau of Mines studied the known prospects 

and claims within and adjacent to the study areas as a 

means of developing a model that would predict the grade 

and tonnage of mineral resources identified in the study

Camp Creek and Cottonwood Creek Wilderness Study Areas, Oregon C3
43° 

42' 

so52'30"

43° 

40'

43° 

371 

30"

43° 

35'

APPROXIMATE BOUNDARY

OF

CAMP CREEK

WILDERNESS

STUDY AREA

(OR-003-031)

Monument 

Peak

1VB Zeo. O/G 

(entire study 

area)

117° 50'

L/C St. Poz, Geo

(entire study area) 

M/BAu[2] 

(entire study 

area)

117° 47'30" 117° 45'

M/B Au [1], Ag

L/C Dia

Stringer shearing 

plant

L/C Dia

Area having moderate mineral resource

potential (M) for gold and (or) silver in 

epithermal veins

Area having moderate mineral resource potential 

(M) for epithermal hot-spring gold and low 

mineral resource potential (L) for other 

commodities as noted

Area having low mineral resource potential (L) 

for diatomite

Levels of certainty of assessment

Data only suggest level of potential

Data give good indication of level of potential

- M/BAu[l],Ag

- L/C St, Poz. Geo 

(entire study area)

-L/B Zeo, O/G 

(entire study area)

M/B Au[2] 

(entire study area)

- Shearing Plant fault 

L/C Dia

APPROXIMATE BOUNDARY

OF

COTTONWOOD CREEK

WILDERNESS

STUDY AREA

(OR-003-032)

Au

Ag

Dia

Geo

O/G

Poz

St

Zeo

Commodities

Gold 

Silver 

Diatomite 

Geothermal energy 

Oil and gas 

Pozzolan 

Building stone 

Zeolite

[ 1 Types of gold deposits

1 Epithermal vein

2 Epithermal hot spring

Geologic map units

Ty Younger volcanic and associated sedimentary rocks

(Tertiary) 

Tw Wildcat Creek Welded Ash-Row Tuff of Kittleman

and others (1965) (Tertiary) 

Tb Basalt flows (Tertiary) Upper part, Tims Peak

Basalt; lower part, basalt flows and volcanic

breccias

Tc Crowley Formation of Hagood (1963a,b) (Tertiary) 

Tbb Basaltic breccia (Tertiary) Phase of the unnamed

igneous complex of Hagood (1963a)

 Contact A Sample site Letter

 Fault refers to table 1

Figure 2. Mineral resource potential, generalized geology, and sample sites of Camp Creek and Cottonwood Creek Wilderness 

Study Areas, Malheur County, Oregon.

C4 Mineral Resources of Wilderness Study Areas: East-Central Oregon
areas. During this process, they collected and analyzed 15 

alluvial and 66 rock samples. Details of samples and 

analytical procedures are described by Benham and Miller 

(1988).

Acknowledgments

J. Douglas Causey of the U.S. Bureau of Mines assisted with the fieldwork in 1987. The authors express 

gratitude to Mr. Bill Holsheimer, Bureau of Land Management geologist of Vale, Oreg., for providing aerial-photograph coverage, maps, and logistical information. Mr. Glen 

Teague, owner of Teague Mineral Products in Adrian, 

Oreg., explained his zeolite deposit and its mining, production, and use. Mr. Andrew Visocan, mine and plant manager of Eagle-Picher Industries, Inc., in Vale, Oreg., described their diatomite deposits, mining, and production. 

Mr. James Can well of the U.S. Bureau of Mines identified 

diatoms and determined the refractive index of volcanic 

glass samples.

APPRAISAL OF IDENTIFIED RESOURCES

By John R. Benham and Michael S. Miller 

U.S. Bureau of Mines

Mining and Exploration History

There has been no exploration activity (staked claims) 

or mining in the Camp Creek and Cottonwood Creek 

Wilderness Study Areas. Two small pits of unknown age 

were found at the north end of the Camp Creek Wilderness 

Study Area. The nearest historical mining activity was at 

the Harper district (diatomite) about 23 mi to the north.

The Harper mining district covers more than 50 mi2 

and has diatomite resources in the lower and upper diatomite members of the Miocene Payette Formation (Moore, 

1937, p. 65-71). A German physician developed a small 

mill in 1910 and shipped limited amounts of diatomite by 

stage to the railroad at Harper, Oreg.; shipments ended 

shortly thereafter with his death. From 1923 until 1933, 

Whiteurth Products Company took over mining (Moore, 

1937, p. 92, 93). In 1971, the railroad was extended into 

the Harper district, and mining was renewed by the American Diato Company. There have been several attempts to 

revitalize the district; the Manville Corporation was evaluating diatomite in the Harper Basin in 1987 (Ramp, 1988, 

p. 42, 43).

Diatomite has been produced since 1985 by EaglePicher Industries at the Celatom mine north of U.S. Highway 20, about 30 mi northwest of the study areas. The 

processing plant is at Vale, Oreg. The diatomite occurs in 

the Cenozoic Juntura Formation of Bowen and others 

(1963) and the Drewsey Formation and is shipped to western markets for use as a filter aid (Andrew Visocan, oral 

commun., 1986; Brittain, 1986).

Zeolite and bentonite have been mined 34 mi east of 

the Cottonwood Creek study area since 1972 by Teague 

Mineral Products, Adrian, Oreg. Production is from one 

zeolite pit and three bentonite pits. Production of zeolite 

and bentonite from Miocene tuffaceous sedimentary rocks 

was 4,000 and 12,000 short tons, respectively, in 1985 and 

5,000 and 14,000 short tons in 1986. Reserves are estimated to be millions of tons (Glen Teague, oral commun., 

1987).

There are no oil and gas or geothermal leases or lease 

applications in the study areas, and industry has shown no 

interest in energy resources exploration in the area.

Identified Resources

Selected sample sites for U.S. Bureau of Mines studies 

are shown on figure 2. Resulting identified mineral resource data are summarized in table 1. All estimates are in 

short tons.

Diatomite

Diatomite, a mineral commodity having significant 

resources in and near the study areas, is an indurated accumulation of siliceous aquatic microscopic plant remains. It 

is used in the United States as filtering material to purify 

water and various food-processing and industrial fluids (67 

percent), as a filler (17 percent), and in numerous other 

purposes (16 percent). Apparent U.S. consumption in 1987 

was estimated at 532,000 short tons. Average price, f.o.b. 

(free on board) plant, was $203 per short ton in 1987 

(Meisinger, 1988).

Thick beds of diatomite crop out at the northeast end 

of the Camp Creek study area, become thinner to the west, 

and extend south along the east side of the Cottonwood 

Creek study area. The diatomite is generally the coherent, 

friable, cake type; however at most outcrops it has been 

broken by landslides. One exposure of diatomite, more 

than 114 ft high, crops out just outside the northeast 

boundary of the Camp Creek study area (fig. 2, table 1, site 

A). Exposures within the study areas are several hundred 

feet across and a few feet to a few tens of feet thick. 

Sample descriptions and analytical results are in Benham 

and Miller (1988).

Diatomite reserves in and adjacent to the Camp Creek 

study area are considered to be marginally economic 

because of the low grade and the competition from 

established mines. Two areas in or near the Camp Creek 

study area were sampled. At site A, a 48-ft-thick section 

of diatomite having a block density of 40 pounds per cubic 

foot (lb/ft3) would yield about 4.3 million tons of inferred 

marginal reserves of diatomite. Underlying this material is 

an additional 66-ft-thick section having a block density of 

about 36 lb/ft3 , which would yield approximately 5.3

Camp Creek and Cottonwood Creek Wilderness Study Areas, Oregon C5
Table 1. Identified mineral resource data for sample sites in and near the Camp Creek and Cottonwood Creek Wilderness Study 

Areas, Malheur County, Oregon

[*, wholly or partly outside study area. As, arsenic; Ba, barium; Eu, europium; Fe, iron; La, lanthanum; Mo, molybdenum; Rb, rubidium; Sb, antimony; 

Th, thorium; U, uranium; W, tungsten; Yb, ytterbium; A12O3, aluminum oxide; CaO, calcium oxide; Fe2O3, ferric oxide; KjO, potassium oxide; MgO, 

magnesium oxide; MnO, manganese oxide; Na2O, sodium oxide; P2O5 , phosphorus pentoxide; SiO2, silicon dioxide; and TiO2, titanium dioxide; ppm, 

parts per million; ppb, parts per billion]

Sample

site 

(fig- 2)

Rock type Description Chemical and mineral resource data

Camp Creek Wilderness Study Area

A* Diatomite

B Breccia zone

Diatomite

D Sand and 

gravel.

Perlite

Pozzolanic 

tuff.

Calcite 

occurrence.

Tuffaceous, brown to white bedded diatomite at least 114 ft thick.

Red, brown, and gray basalt and rhyolite 

(?) breccia with stretched vesicles and 

some opal-filled vesicles. Some 

limonite staining and silicified fractures 

and chalcedony/opal-rich cement.

Bedded, brown, green, and white 

diatomite, 50 ft thick in an area 

obscured by talus, slopewash, and 

landslides.

Subangular to subrounded sand, pebbles, 

cobbles, and numerous boulders of 

basalt, andesite, and rhyolite. Extensive deposits along Camp and Cottonwood Creeks.

Glassy welded tuff having slight perlite 

texture.

Example of tuffaceous beds that 

underlie much of study area. Thinbedded to massive, brown, black, gray, 

and white pumiceous diatomaceous 

tuff, nearly horizontal.

Clear to milky crystals and fragments of 

calcite in float.

Block density is 36 to 40 lb/ft3 . Melosira, Tetracyclus, 

Stephanodiscus, Nayicula, and sponge spicules identified. 

A 48-ft-long sample contains 77.2 percent SiO2 6.8 

percent A12O3 , 3.52 percent Fe2O3 , 1.21 percent MgO, 

1.31 percent CaO, 0.47 percent Na^O, 0.33 percent K^O, 

0.31 percent TiO2, less than 0.01 percent P2O5 , 0.04 

percent MnO; loss on ignition was 8.87 percent. This 

layer contains inferred, marginally economic reserves of 

9.6 million short tons of diatomite.

Twenty-two samples average 7 ppm Mo, 6 ppm As, 0.8 

ppm Sb, 1,700 ppm Ba, and 11 ppm W. These concentrations are too low by a factor of about 100 to be 

economic.

Block density 40 Ib per ft3 . Melosira, Analus, Cymbella, 

Tetracylus, Cyclotella, and sponge spicules identified. 

One grab sample contains 76.67 percent SiO2, 8.27 percent Alp3, 2.16 percent Fe2O3 , 0.88 percent MgO, 1.55 

percent CaO, 0.86 percent NajO, 1.54 percent K^O, 0.25 

percent TiO2, less than 0.01 percent P2O5 , 0.02 percent 

MnO; loss on ignition was 8.18 percent. Marginally 

economic reserves of 250,000 short tons are inferred.

At least 2.5 million yds3 of inferred marginal reserves in 

and near Camp Creek study area and 2.5 million yds3 of 

inferred marginal reserves in and near Cottonwood Creek 

study area.

Density of expanded perlite is 27.81 lb/ft3 ; standard is 3 Ib/ 

ft3 . This perlite is too low in grade to be economic.

Two chip samples 20.5 and 33.0 ft long have 69.63 percent 

and 58.52 percent SiO2, 14.19 percent and 15.67 percent 

AljOj, 1.37 and 8.28 percent Fe2O3 , 0.69 percent and 

0.98 percent MgO, 1.39 percent and 2.23 percent CaO, 

2.53 percent and 1.42 percent Na2O, 5.39 percent KjO, 

0.11 and 1.02 percent TiO2, less than 0.01 percent and 

0.05 percent P2O5 , 0.14 percent and 0.17 percent MnO; 

loss on ignition was 6.13 percent and 8.89 percent. 

Camp Creek study area is estimated to contain inferred 

marginal reserves of at least 40 million short tons of 

pozzolanic tuff in the reserve base.

Calcite mostly milky and twinned; most crystals less than 1 

in. across. Occurrence is too small and too low grade to 

be economic.

C6 Mineral Resources of Wilderness Study Areas: East-Central Oregon
Table 1 . Identified mineral resource data for sample sites in and near the Camp Creek and Cottonwood Creek Wilderness Study 

Areas, Malheur County, Oregon Continued

Sample

site Rock type 

(fig. 2)

Description Chemical and mineral resource data

Cottonwood Creek Wilderness Study Area

H Diatomite

I Diatomite

Pozzolanic 

tuff.

K

L*

Opalized 

rhyolite.

Building 

stone.

Gray to white, green to brown tuffaceous 

diatomite.

Pale red, brown to gray bedded diatomite 

and tuff; ilmenite(?) grains as large as 

1 mm. Diatomite about 10 ft thick in 

outcrop.

Very fine grained, white to tan tuff at 

least 100 ft thick.

Gray, fine-grained porphyritic rhyolite 

with yellow to green fracture coatings 

of opal. Exposure at least 200 ft 

across.

Yellow, brown, and gray slabby porphyritic rhyolite in talus. Slabs are 

concave to wavy, 0.5 to 3.0 in. thick, 4 

to 20 in. wide, and 6 to 30 in. long. 

Slabs are hard and have a glassy ring 

when struck.

Five samples contain impure, clayey pumiceous diatomite 

with Melosira diatoms. Occurrence is too low grade to 

be economic.

Block density is 40 lb/ft3 . The estimated 4,000 short tons 

of diatomite is not considered to be economic.

Tuffaceous beds similar to those at site F in the Camp 

Creek study area. Cottonwood Creek study area is estimated to contain inferred marginal reserves of at least 10 

million short tons of pozzolanic tuff in the reserve base.

One grab sample contains 6 ppm As, 1,500 ppm Ba, 4 

ppm Eu, 1.9 percent Fe, 56 ppm La, 6 ppm Mo, 99 ppm 

Rb, 0.3 ppm Sb, 11 ppm Th, 5.2 ppm U, 3 ppm W, and 

9 ppm Yb. These concentrations are too low by a factor 

of about 100 to be economic.

Assuming a thickness of 10 ft, a width of 200 ft, and a 

length of 5,000 ft, inferred marginally economic reserves 

of more than 740,000 short tons are estimated.

million tons of inferred marginal reserves. At site C (fig. 

2, table 1), the diatomite has a block density of about 40 lb/ 

ft3 . Data indicate approximately 250,000 tons of inferred 

marginal reserves of diatomite at this site, although talus 

and slopewash limit the exposures.

Two areas of diatomaceous material in the Cottonwood 

Creek study area were sampled. One (fig. 2, table 1, site H) 

is tuffaceous and too impure to consider as a resource. 

Diatomite at site I is interlayered with coarse-grained 

pumice and has a block density of about 40 lb/ft3 . It would 

yield about 4,000 tons of inferred subeconomic diatomite 

resources.

Moore (1937, p. 113) considered diatomite having a 

block density of less than 30 lb/ft3 to be excellent, that of 

30 to 35 lb/ft3 to be good, that of 35 to 40 lb/ft3 to be fair, 

and that of greater than 40 lb/ft3 to be poor. Accordingly, 

the quality of diatomite from the study areas is rated poor 

to fair. For some applications, however, denser impure 

diatomite may be superior to lighter diatomite. Preliminary 

mining costs were estimated by the methods of Benjamin 

and Gale (1984) using January 1988 costs. They ranged

from $4.50 per ton at 500 tons per day and no stripping to 

$21 per ton at 100 tons per day and a 2:1 stripping ratio. 

Flotation, if used, would cost $14 to $30 per ton. Other 

processing costs were not estimated because of the many 

possible end uses. Truck transportation for 50 mi would 

cost at least $14 per ton.

Pozzolan

Pozzolans are siliceous aluminous iron-bearing materials found in many volcanic tuffs, in diatomite, and in ash 

from coal burning. Pozzolan may be used to replace relatively expensive cement and may improve the properties of 

concrete. In 1985, 11.4 million tons of fly ash were consumed as pozzolan (Sam Tyson, American Coal Ash Association, oral commun., 1987). Ash from coal burning satisfies most of the pozzolan markets in the United States.

Chemical analyses show that most of the tuffaceous 

sediments, including some diatomite, in the Camp Creek 

study area meet chemical requirements for natural pozzolan 

for cement mixtures (American Society of Testing

Camp Creek and Cottonwood Creek Wilderness Study Areas, Oregon C7
Materials, 1985) (fig. 2, table 1, sites A, C, F); sediments 

at site J in the Cottonwood Creek study area are similar. 

Multiple tuffaceous beds hundreds of feet thick underlie the 

study areas. Only a small amount could be mined by 

surface methods, but the reserve base includes an inferred 

resource of at least 50 million tons of pozzolan-bearing 

material: 40 million tons in the Camp Creek study area, and 

10 million tons in the Cottonwood Creek study area.

Additional tests (such as total available alkali, sulfur 

content, water content, pozzolan activity index, water requirement, cement strength, and concrete applications) 

would be needed before assuming that the material would 

be useful for a specific pozzolan application. January 1988 

mining costs (Benjamin and Gale, 1984) for pozzolanic 

tuffs in the study areas were estimated at $7 per ton for 

surface mining of a 500,000-ton deposit at 500 tons per day 

with no stripping. Subsequent processing costs were not 

estimated, but truck haulage for 50 mi would cost at least 

$14 per ton. Use of marginally economic resources of 

tuffaceous sediments as pozzolan is unlikely in the near 

future because of the distance to markets and the competition from established sources. A market within 10 or 20 

mi, such as dam or highway construction, could make 

economic use of pozzolan sediments from the study areas.

Sand and Gravel

Sand and gravel occurs extensively along Camp Creek 

and Cottonwood Creek. The alluvium at site D (fig. 2, 

table 1) is subangular to subrounded and composed mainly 

of basalt, andesite, and rhyolite. The gravel is pebbly to 

cobbly with numerous boulders. Along Cottonwood Creek 

and the lower reaches of Camp Creek, the alluvium is 

hundreds of feet wide and ten or more feet thick. Sand and 

gravel from the study areas would only be mined for local 

use such as road and dam construction. Estimated surface 

mining costs for sand and gravel, using the method of 

Benjamin and Gale (1984), are about $3.40 per ton ($5.10 

per yd3) assuming a 500,000-ton deposit (330,000 yd3), 

1,000-ton (700-yd3)-per-day operation, and 1.5 tons per yd3 

(January 1988 costs). Subsequent processing costs were 

not estimated. Truck transportation for 10 mi would cost 

about $5.50 per ton ($8.25 per yd3 ; January 1988 costs). 

Sand and gravel are considered to be a marginally economic resource of at least 2.5 million yd3 in each of the 

study areas.

Stone (Dimension and Decorative)

Building stone is used in the United States for building 

construction (47 percent), monuments (26 percent), rubble 

(14 percent), curbing (8 percent), flagging (4 percent), and 

other uses (1 percent). Prices in Spokane, Wash., for rock 

similar to that in or near the study areas ranged from $50 

per ton to about $130 per ton in 1988.

The slabby porphyritic Littlefield Rhyolite of Kittleman and others (1965) crops out along the road down 

Alder Creek to Cottonwood Creek (fig. 2, table 1, site L). 

Lichens and a yellow- to brown-weathering rind may cover 

the rhyolite; where fresh, the rhyolite is gray to yellow. 

Talus of slabby rhyolite lies along the road adjacent to the 

Cottonwood Creek study area. Broken slabs are 0.5 to 3.0 

in. thick, 4 to 20 in. wide and 6 to 30 in. long, and slightly 

wavy to concave; they are hard and brittle, and have a 

glassy ringing sound when struck. Slabby stone such as 

this is used as decorative facing on walls, in fences, and as 

flagging. January 1988 cost of mining the slabby rhyolite 

along Alder Creek was estimated (using methods of Benjamin and Gale, 1984) at more than $9 per ton for a 

200,000-ton deposit mined at 60 tons per day with no stripping. Cost of subsequent processing was not estimated. 

Truck transportation for 100 miles would cost about $15 

per ton (January 1988 costs). The slabby rhyolite is considered to constitute inferred marginal reserves of at least 

740,000 tons in and adjacent to the Cottonwood Creek 

study area.

Mineral Occurrences

Metallic Minerals

Samples of silicified brecciated volcanic rocks along 

the Shearing Plant fault (Hagood, 1963a, p. 133,134) in the 

Camp Creek study area contain small amounts of gold, 

molybdenum, arsenic, antimony, barium, and tungsten (fig. 

2, table 1, site B) . Extensions of the Shearing Plant fault 

into the Cottonwood Creek study area are not known to be 

mineralized. Samples of red limonitic tuff in the Camp 

Creek study area, possibly in or near fault zones, also contain minor antimony. One sample of rhyolite breccia and 

one sample of fumerolic vesicular basalt (scoria) from the 

western part of the Camp Creek study area contain 7 parts 

per billion (ppb) and 8 ppb, respectively, of gold, about 

twice the expected amount for basalt (Krauskopf, 1979). 

Samples of brecciated opalized rhyolite from the Cottonwood Creek study area east of Gugle Ranch (fig. 2, table 1, 

site K) contain small amounts of arsenic, molybdenum, 

rubidium, tungsten, barium, lanthanum, and ytterbium.

None of the rock samples contain any metallic commodities in economic amounts. None of the alluvial 

samples contain detectable detrital gold or economic heavy 

minerals. The distribution and content of gold, antimony, 

barium, arsenic, molybdenum, and tungsten indicate mineralization in silicified breccia along the Shearing Plant fault 

(Hagood, 1963a), in limonitic tuff, and in opalized rhyolite 

breccia east of Gugle Ranch, but metallic contents are too 

low, by factors of about 100, to be economic.

Nonmetallic Materials

A few pounds of calcite crystals and fragments were 

found in float northeast of Gugle Ranch along Cottonwood

C8 Mineral Resources of Wilderness Study Areas: East-Central Oregon
Creek in the Camp Creek study area (fig. 2, table 1, site G). 

The calcite fills 1- to 5-in. voids in a volcanic breccia, and 

most crystals are less than 1 in. across. Vugs filled by 

calcite are uncommon; only one piece in float was found. 

The calcite is mostly small, milky, and twinned and is not 

an optical grade.

Volcanic glass is abundant in the northern part of the 

Camp Creek study area as fragments and blebs in a coarse 

glassy tuff at least 150 ft thick. A yellow to brown matrix 

of clay and carbonate minerals makes up about 20 percent 

of the tuff. Glass from along the west boundary of the 

Camp Creek study area has a refractive index of 1.576, 

determined by oil immersion, that does not indicate hydration. Another sample (fig. 2, table 1, site E) is a glassy 

welded tuff with a slightly perlitic texture; its refractive 

index indicates hydration, and expansion testing indicates a 

noncommerical perlite.

In checking for zeolite minerals, much of the altered 

tuffaceous rocks and diatomite tested positive (Helfferich, 

1964) for exchangeable cations, but only weak scattered Xray diffraction peaks were found. Calcite, quartz, feldspar, 

kaolinite, smectite, and cristobalite were identified by Xray diffraction, but no zeolites were found.

Recommendations for Further Work

Drilling and further testing, especially beneficiation 

tests, would give more information about the quality and 

uses of the diatomite. Pozzolan testing, marketing, and 

detailed cost studies could be performed. Additional 

sampling and mapping would help evaluate the low-grade 

mineralization along siliceous zones of the Shearing Plant 

fault (Hagood, 1963, p. 133-134), in opalized rhyolite 

breccia near Gugle Ranch, and in tuffs and breccias 

throughout the study areas.

ASSESSMENT OF MINERAL RESOURCE 

POTENTIAL

By William J. Keith, Robert L. Turner, and Andrew Griscom 

U.S. Geological Survey

Geological Studies

The Camp Creek and Cottonwood Creek Wilderness 

Study Areas, which are joined along a section of Cottonwood Creek, are in the High Lava Plains subprovince of the 

Columbia Intermontane physiographic province. The surface geology consists of a continuous series of flat-lying 

mafic and silicic lava flows, pyroclastic deposits, and associated sediments, all of Miocene and (or) Pliocene age. At 

present, the composition of the basement rocks is unknown, 

but they could be composed of older basin material.

Individual rock units mapped in the study areas are in 

the same stratigraphic order as that proposed by Hagood 

(1963a, b) but are shown as only five map units on the 

generalized geologic map (fig. 2).

The oldest map unit in the area consists of basalts of 

the basaltic breccia phase of the unnamed igneous complex 

of Hagood (1963a). In the study area, these rocks are 

columnar-jointed porphyritic basalt flows containing large 

tabular plagioclase phenocrysts and vugs of various sizes.

The Crowley Formation of Hagood (1963a, b), which 

overlies the basaltic breccia, consists mostly of rhyolitic 

and basaltic lava flows, ash-flow tuffs, and associated 

sedimentary rocks.

Overlying these rocks is a unit consisting largely of 

basalt flows. The oldest rocks in this map unit consist of 

a sequence of basalt flows and volcanic breccias; the upper 

part consists of the Tims Peak Basalt.

Locally, the Wildcat Creek Welded Ash-Flow Tuff of 

Kittleman and others (1965) overlies part of the Crowley 

Formation.

The youngest map unit in the study areas is here designated as the "younger volcanic and associated sedimentary rocks." This unit consists of the Squaw Creek unit of 

Hagood (1963a) (a sequence of fine-grained vitric tuffs and 

porcelaneous rocks that are interbedded with shale and that 

may locally contain diatomite), an unnamed andesite, the 

basalt of Willow Springs, the Grassy Mountain Formation 

of Kittleman and others (1965) (interbedded basalt, volcanic and arkosic sandstone, ash, conglomerate, and pumice breccia), the Bully Creek Formation of Kittleman and 

others (1965) (interbedded volcanic sandstone, conglomerate, and claystone; tuff; basalt; and diatomite), and unnamed tuff breccia.

The study areas are traversed by a series of northnortheast-trending high-angle normal faults having offsets

of tens to hundreds of feet. Few rocks along these faults 

are extensively altered.

Geochemical Studies

A reconnaissance geochemical survey was conducted 

in the Camp Creek and Cottonwood Creek Wilderness 

Study Areas in the summer of 1986. Minus-80-mesh 

stream sediments and heavy-mineral concentrates derived 

from them were collected at 31 sites, and rocks were collected from 17 sites for this study. Analytical data and a 

description of the sampling and analytical techniques are 

given in Jones and others (1988).

Rocks from 7 of the 17 sample sites contain elements 

having anomalously high values; 6 of these sites are in the 

east-northeastern part of the Camp Creek and Cottonwood 

Creek study areas. The rock samples contain anomalous 

values for molybdenum (5-20 parts per million, ppm), 

bismuth (2-4 ppm), arsenic (6-9 ppm), and zinc (up to 200 

ppm). These anomalous concentrations, however, are not

Camp Creek and Cottonwood Creek Wilderness Study Areas, Oregon C9
high enough to be considered more than intrinsic variations 

within the rock types of the study areas.

Analyses of the minus-80-mesh stream sediments 

show anomalous values for arsenic (5-25 ppm), bismuth 

(2-3 ppm), cadmium (1-1.6 ppm), manganese (up to 5,000 

ppm), molybdenum (5-7 ppm), and zinc (200-240 ppm). 

These anomalous values are so low that they probably 

reflect only intrinsic variations within the rock types of the 

study areas.

Analyses of the heavy-mineral concentrates from the 

two study areas show no anomalous data.

Geophysical Studies

An aeromagnetic survey of the study areas was flown 

in 1976 and 1977 by the Geophysics Group at Oregon State 

University as part of a study of the Vale-Owyhee geothermal area (Boler, 1978). The aeromagnetic data were collected along parallel east-west flightlines spaced 1.0 mi 

apart at a constant flight elevation of 7,000 ft above sea 

level. The Earth's main field was subtracted from the data, 

which were then plotted by machine and hand-contoured at 

a scale of 1:62,500. A final residual map was drafted at a 

scale of 1:125,000.

Additional aeromagnetic data are available in the atlas 

on the Boise quadrangle (scale, 1:500,000) published for 

the Department of Energy (geoMetrics, Inc., 1979). These 

data consist of aeromagnetic profiles flown east-west by 

helicopter at an average height of 400 ft above ground and 

a profile spacing of 3 mi. Three of these profiles (numbers 

80, 90, and 100) cross the study areas.

Variations in the Earth's magnetic field on an aeromagnetic residual map are, in general, caused by variations 

in the amounts of magnetic minerals in different rock units, 

magnetite being the common magnetic mineral in this area. 

Magnetic minerals, where locally either concentrated or 

absent, may cause a high or low magnetic anomaly that can 

be a guide to mineral occurrences or deposits. Boundaries 

between magnetic and relatively less magnetic rock units 

are located approximately at the steepest gradient on the 

flanks of the magnetic anomaly.

Because of the preponderance of lava flows and other 

volcanic rocks in this area, one might expect that the 

majority of the anomalies are caused by volcanic rocks. 

However, the survey aircraft was generally 2,000 to 3,500 

ft above the surface of the ground in this area, a distance 

sufficiently great to suppress most of the short-wave-length 

anomalies generated by rocks at or near the surface. The 

contoured magnetic map shows a broad subcircular magnetic high about 8 mi in diameter and about 400 gammas 

in amplitude. This high is centered over the Cottonwood 

Creek Wilderness Study Area but extends to the northwest 

about halfway across the Camp Creek Wilderness Study 

Area. The high, because of its great width and form, 

represents a causative rock mass at least 5,000 ft thick

which does not appear to be exposed and which may be an 

intrusion into the igneous complex that forms the volcanic 

basement in this area (Kittleman and others, 1967). The 

causative mass and the magnetic high are terminated on the 

east by the Shearing Plant fault. The economic potential of 

this possible intrusion is unknown. The intrusion roof, on 

the basis of local geologic structure, would probably be no 

higher than about 3,700 ft above sea level.

Another major magnetic feature is a distinctive northeast-trending magnetic low, about 6 mi long by 3 mi wide, 

located just outside the northwest border of the Camp 

Creek Wilderness Study Area. This anomaly is about 400 

gammas in amplitude and correlates well with an uplifted 

oval basement area of the igneous complex. Two intrusive 

rhyolite plugs centered within this oval area display intense 

local magnetic lows having amplitudes in excess of 1,500 

gammas at an altitude of 300 ft above ground (geoMetrics, 

Inc., 1979, line 80). The lows are caused by reverse 

remanent magnetization, certainly in the rhyolite plugs and 

perhaps also in the uplifted igneous complex. Another 

possible cause for the low might be a large concealed 

shallow-depth siliceous pluton related to the plugs and to 

the doming. The absence of significant rock alteration in 

this area suggests that there is little, if any, economic significance to these aeromagnetic observations.

A gravity survey of this same region has been described and interpreted by Lillie (1977). The average station spacing is about 5 mi, and 12 gravity stations are 

located within or near the two study areas. The data are 

presented as a complete Bouguer anomaly map having a 

contour interval of 2 milligals (mGal) and a reduction 

density of 2.67 grams per centimeter cubed. Two gravity 

features are apparent: (1) a linear gravity gradient trending 

north-south and sloping down to the west along the east 

border of the two study areas, and (2) a small gravity high 

of about 5 mGal located directly northwest of the Camp 

Creek Wilderness Study Area. The first feature probably is 

associated with the Shearing Plant fault on the east side of 

the study areas. The second feature correlates with the 

magnetic low described above and is probably caused by 

the uplifted rocks of the igneous complex. These gravity 

features probably have no economic significance in these 

study areas, although thermal springs and wells are associated with major north-south faults in the Vale Known 

Geothermal Resource Area located 45 mi to the northeast.

Aerial gamma-ray spectrometer measurements are 

available along the aeromagnetic profiles (geoMetrics, Inc., 

1979). The anomalies are 3 to 4 standard deviations above 

the average values for the Boise quadrangle. Examination 

of these anomalies in relation to the geologic map of Kittleman and others (1967) shows that the anomalies appear 

to be associated with rocks of the Littlefield Rhyolite. The 

anomalies indicate that these rocks probably contain the 

largest amounts of uranium, potassium, and thorium in this 

part of the quadrangle. These amounts are probably within 

the normal ranges for this type of igneous rock and thus do

C10 Mineral Resources of Wilderness Study Areas: East-Central Oregon
not necessarily indicate any resources of economic significance.

Mineral and Energy Resource Potential

The Camp Creek and Cottonwood Creek Wilderness 

Study Areas have moderate mineral resource potential for 

an epithermal-vein-type gold deposit along the Shearing 

Plant fault (fig. 2). Both study areas have moderate mineral 

resource potential for hot-spring-type gold deposits 

throughout the area. The resource potential in both study 

areas is low for diatomite deposits in the eastern parts and 

for zeolite minerals, pozzolan, building stone, geothermal 

energy, and oil and gas over the entire area.

The Shearing Plant fault (fig. 2) is a high-angle normal 

fault trending about N. 10° E. Breccia zones, small quartz 

stringers, and silicified joints radiate from the fault in many 

places. Low-level geochemical anomalies occur in the 

stream sediments in the northeastern part of the study areas 

near the fault; some of the breccia zones show siliceous 

alteration. These data suggest resource potential for deposits of epithermal gold and (or) silver. Although the amount 

of alteration is small and the geochemical anomalies are 

low level, the geologic setting is similar to other areas that 

contain epithermal gold deposits in Malheur County 

(Wheeler, 1988). These data support moderate mineral 

resource potential (certainty level B) for a small deposit of 

gold and (or) silver somewhere along the Shearing Plant 

fault in both study areas.

Samples of altered rhyolite and basalt from the study 

areas contain 7 ppb and 8 ppb gold, respectively (Benham 

and Miller, 1988, p. 20). These values are in the background range for extrusive felsic rocks (0.1-113 ppb) and 

extrusive mafic rocks (0.1-230 ppb) (Boyle, 1979, p. 38). 

However, the presence of gold, the relatively high heat 

flow, the sporadic occurrence of opal, and the areas of 

brecciated volcanic rock in the study areas suggest the 

possibility of hot-spring-type gold mineralization (Berger, 

1986). Wheeler (1988) notes epithermal gold prospects 

hosted by pyroclastic and sedimentary rocks in northern 

Malheur County; those rocks can be correlated with similar 

rocks in these study areas. These data suggest moderate 

mineral resource potential (certainty level B) for epithermal 

hot-spring-type gold deposits throughout the study areas.

Diatomite occurs in the younger volcanic and associated sedimentary rocks along the east side of both study 

areas (fig. 2) and is associated with laucustrine sediments. 

The limited quantity, low quality of the diatomite, distance 

to market, and the abundance of higher quality material in 

other parts of the surrounding area lead to the conclusion of 

low mineral resource potential (certainty level C) for minable diatomite in several areas of the eastern part of both 

study areas.

There is low mineral resource potential (certainty level 

B) for zeolite deposits throughout both study areas. Both 

areas are underlain by siliceous volcanic rocks that could

be altered to zeolite minerals. Geothermal systems may 

occur in the study areas, as indicated by the presence of 

opalized rocks. These criteria suggest the possibility of 

zeolite deposits but do not necessarily indicate that they 

exist, thus the certainty level B.

Building stone resources occur in rhyolite of the 

Crowley Formation. Because both study areas are underlain by these rhyolites, both areas have potential for a 

deposit of usable building stone. However, large areas of 

this rhyolite, as well as other suitable slabby rhyolites, are 

exposed in adjacent and distant areas that are more suitable 

for exploitation. Therefore, the mineral resource potential 

for exploitable building stone in these study areas is low 

(certainty level C).

Siliceous tuffs suitable for use as pozzolan occur 

throughout both study areas; hence, both areas are considered to have resource potential for a pozzolan deposit. 

However, because the established industry source of pozzolan is a by-product of coal-burning operations and because 

there is overburden to be removed in the study areas, the 

mineral resource potential for pozzolan in the study areas is 

low (certainty level C).

Both study areas have low potential (certainty level Q 

for high-temperature (194 to 302 °F) geothermal energy 

resources. No thermal springs are known to exist in the 

study areas, and only small areas of hydrothermal alteration 

were found. However, the study areas have relatively high 

heat flow approximately 100 milliwatts per square meter 

(Muffler, 1979, map 1). The potential for geothermal 

resources is also somewhat enhanced by the presence of 

four hydrothermal convection systems within a 50-mi radius of the study areas (Riverside Area, Little Valley Area, 

Neal Hot Springs, and Vale Hot Springs; Brook and others, 

1979). These systems have estimated reservoir temperatures that range from 244±50 °F (Riverside Area) to 

370±46 °F (Neal Hot Springs) (Brook and others, 1979).

There are no known occurrences of oil or gas in the 

study areas, nor are there any indications of any in the 

water wells. However, source beds of older basin material 

may underlie or be interbedded with the older rocks at 

depth (Fouch, 1983). The maturation level for stable 

hydrocarbons may have been exceeded in the older basin 

fill of the study area (Fouch, 1983), in which case any 

petroleum in the sediments would not have been preserved. 

However, because the thermal history has not been established, it is concluded that both study areas have low resource potential (certainty level B) for oil and gas.

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

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County, Oregon: Masters Abstracts, v. 1, no. 4, p. 13.

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1752-1754.

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and Cottonwood Creek Wilderness Study Area, Malheur 

County, Oregon: U.S. Geological Survey Open File Report 

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Cenozoic stratigraphy of the Owyhee region, southeastern 

Oregon: Eugene, University of Oregon, Museum of Natural 

History Bulletin 1, 45 p.

Krauskopf, K.B., 1979, Introduction to geochemistry: New York, 

McGraw-Hill, 617 p.

Lillie, R.J., 1977, Subsurface geologic structure of the Vale, 

Oregon, Known Geothermal Resource Area from the interpretation of seismic reflection and potential field data: Corvallis, 

Oregon State University, M.S. thesis, 52 p.

Mathews, G.W., and Blackburn, W.H., 1983, Assessment of 

geology, energy, and mineral (GEM) resources, Lake Owyhee 

GEM resource area (OR-030-16), Malheur County, Oregon: 

San Francisco, Calif., Terradata, 38 p. [prepared for U.S. 

Bureau of Land Management].

McKelvey, V.E., 1972, Mineral resource estimates and public 

policy: American Scientist, v. 60, p. 32-40.

Meisinger, A.C., 1988, Diatomite, in Mineral commodity summaries, 1988: U.S. Bureau of Mines, p. 48^49.

Moore, B.N., 1937, Nonmetallic mineral resources of eastern 

Oregon: U.S. Geological Survey Bulletin 875, 180 p.

Muffler, L.J.P., ed., 1979, Assessment of geothermal resources of 

the United States 1978: U.S. Geological Survey Circular 

790, 163 p., 3 maps, scales 1:2,500,000, 1:5,000,000, 

1:1,000,000.

Ramp, Len, 1988, Exploration and mining activity in Oregon, 

1987: Oregon Geology, v. 50, no. 4, p. 39-44.

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

Geological Survey Circular 831, 5 p.

Wheeler, G.R., 1988, Epithermal gold deposits in eastern Oregon: 

Mining Engineering, v. 40, no. 11, p. 1033-1035.

C12 Mineral Resources of Wilderness Study Areas: East-Central Oregon
APPENDIXES
DEFINITION OF LEVELS OF MINERAL RESOURCE POTENTIAL 

AND CERTAINTY OF ASSESSMENT

LEVELS OF RESOURCE POTENTIAL

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

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

indicating presence of resources, and where evidence indicates that mineral concentration has taken place. 

Assignment of high resource potential to an area requires some positive knowledge that mineral-forming processes 

have been active in at least part of the area.

M 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 for resource accumulation, and (or) where an application of mineral-deposit models 

indicates favorable ground for the specified type(s) of deposits.

L 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 little or no indication of having 

been mineralized.

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

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

moderate, or high level of resource potential.

LEVELS OF CERTAINTY

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

B Available information only 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.

Z

LJU

oCL 

LLJ 

U

Q£

OC/5

LLJ

LLJ

A

U/A

UNKNOWN POTENTIAL

B

H/B

HIGH POTENTIAL

M/B

MODERATE POTENTIAL

L/B

LOW POTENTIAL

C

H/C

HIGH POTENTIAL

M/C

MODERATE POTENTIAL

L/C

LOW POTENTIAL

D

H/D

HIGH POTENTIAL

M/D

MODERATE POTENTIAL

L/D

LOW POTENTIAL

N/D

NO POTENTIAL

LEVEL OF CERTAINTY

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.

C14 Mineral Resources of Wilderness Study Areas: East-Central Oregon
RESOURCE/RESERVE CLASSIFICATION

ECONOMIC

MARGINALLY 

ECONOMIC

SUBECONOMIC

IDENTIFIED RESOURCES

Demonstrated

Measured

Resc

Indicated

;rves

Marginal 

Reserves

Demonstrated 

Subeconomic

Resources

i

i

Inferred

Inferred 

Reserves

Inferred 

Marginal 

Reserves

Inferred 

Subeconomic 

Resources

UNDISCOVERED RESOURCES

Probability Range

Hypothetical Speculative

Major elements of mineral resource classification, excluding reserve base and inferred reserve base. Modified from McKelvey, V.E., 1972, Mineral 

resource estimates and public policy: American Scientist, v. 60, p. 32-40; and 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.

Camp Creek and Cottonwood Creek Wilderness Study Areas, Oregon CI5
GEOLOGIC TIME CHART

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

EON

Phanerozoic

Proterozoic

Archean

pre-Archean2

ERA

Cenozoic

Mesozoic

Paleozoic

Late Proterozoic

Middle Proterozoic

Early Proterozoic

Late Archean

Middle Archean

Early Archean

PERIOD

Quaternary

Neogene

Subperiod

Tertiary _ .

v_* retaceou s

Jurassic

Triassic

Permian

Pennsylvanian 

Carboniferous

Mississippian

Devonian

Silurian

Ordovician

Cambrian

_._.__. nfino?^- -

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

ACE ESTIMATES OF 

BOUNDARIES IN 

MILLION YEARS (Ma)

0.010

1.7

5

24

1 Q

55

66

96

1 3Q

205

 -240

 290

 33O

 360 

 410

A *>C

 500

1 oUU

£J\AJ

 3000

J*T\AJ

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

informal time term without specific rank.

C16 Mineral Resources of Wilderness Study Areas: East-Central Oregon


SELECTED SERIES OF U.S. GEOLOGICAL SURVEY PUBLICATIONS

Periodicals

Earthquakes & Volcanoes (issued bimonthly). 

Preliminary Determination of Epicenters (issued monthly).

Technical Books and Reports

Professional Papers are mainly comprehensive scientific reports of 

wide and lasting interest and importance to professional scientists and engineers. Included are reports on the results of resource studies and of 

topographic, hydrologic, and geologic investigations. They also include 

collections of related papers addressing different aspects of a single scientific topic.

Bulletins contain significant data and interpretations that are of lasting scientific interest but are generally more limited in scope or 

geographic coverage than Professional Papers. They include the results 

of resource studies and of geologic and topographic investigations; as well 

as collections of short papers related to a specific topic.

Water-Supply Papers are comprehensive reports that present significant interpretive results of hydrologic investigations of wide interest 

to professional geologists, hydrologists, and engineers. The series covers 

investigations in all phases of hydrology, including hydrogeology, 

availability of water, quality of water, and use of water.

Circulars present administrative information or important scientific 

information of wide popular interest in a format designed for distribution 

at no cost to the public. Information is usually of short-term interest.

Water-Resources Investigations Reports are papers of an interpretive nature made available to the public outside the formal USGS publications series. Copies are reproduced on request unlike formal USGS 

publications, and they are also available for public inspection at 

depositories indicated in USGS catalogs.

Open-File Reports include unpublished manuscript reports, maps, 

and other material that are made available for public consultation at 

depositories. They are a nonpermanent form of publication that may be 

cited in other publications as sources of information.

Maps

Geologic Quadrangle Maps are multicolor geologic maps on 

topographic bases in 71/2- or 15 -minute quadrangle formats (scales mainly 1:24,000 or 1:62,500) showing bedrock, surficial, or engineering geology. Maps generally include brief texts; some maps include structure 

and columnar sections only.

Geophysical Investigations Maps are on topographic or planimetric 

bases at various scales; they show results of surveys using geophysical 

techniques, such as gravity, magnetic, seismic, or radioactivity, which 

reflect subsurface structures that are of economic or geologic significance. 

Many maps include correlations with the geology.

Miscellaneous Investigations Series Maps are on planimetric or 

topographic bases of regular and irregular areas at various scales; they 

present a wide variety of format and subject matter. The series also includes 71/2-minute quadrangle photogeologic maps on planimetric bases 

which show geology as interpreted from aerial photographs. Series also 

includes maps of Mars and the Moon.

Coal Investigations Maps are geologic maps on topographic or 

planimetric bases at various scales showing bedrock or surficial geology, stratigraphy, and structural relations in certain coal-resource areas.

Oil and Gas Investigations Charts show stratigraphic information 

for certain oil and gas fields and other areas having petroleum potential.

Miscellaneous Field Studies Maps are multicolor or black-andwhite maps on topographic or planimetric bases on quadrangle or irregular areas at various scales. Pre-1971 maps show bedrock geology 

in relation to specific mining or mineral-deposit problems; post-1971 

maps are primarily black-and-white maps on various subjects such as 

environmental studies or wilderness mineral investigations.

Hydrologic Investigations Atlases are multicolored or black-andwhite maps on topographic or planimetric bases presenting a wide range 

of geohydrologic data of both regular and irregular areas; principal scale 

is 1:24,000 and regional studies are at 1:250,000 scale or smaller.

Catalogs

Permanent catalogs, as well as some others, giving comprehensive listings of U.S. Geological Survey publications are available under 

the conditions indicated below from the U.S. Geological Survey, Books 

and Open-File Reports Section, Federal Center, Box 25425, Denver, 

CO 80225. (See latest Price and Availability List)

"Publications of the Geological Survey, 1879-1961" may be purchased by mail and over the counter in paperback book form and as a 

set of microfiche.

"Publications of the Geological Survey, 1962-1970" may be purchased by mail and over the counter in paperback book form and as a 

set of microfiche.

"Publications of the U.S. Geological Survey, 1971-1981" may be 

purchased by mail and over the counter in paperback book form (two 

volumes, publications listing and index) and as a set of microfiche.

Supplements for 1982,1983,1984,1985,1986, and for subsequent 

years since the last permanent catalog may be purchased by mail and 

over the counter in paperback book form.

State catalogs, "List of U.S. Geological Survey Geologic and 

Water-Supply Reports and Maps For (S tate)," may be purchased by mail 

and over the counter in paperback booklet form only.

"Price and Availability List of U.S. Geological Survey Publications," issued annually, is available free of charge in paperback booklet form only.

Selected copies of a monthly catalog " New Publications of the U. S. 

Geological Survey" available free of charge by mail or may be obtained 

over the counter in paperback booklet form only. Those wishing a free 

subscription to the monthly catalog "New Publications of the U.S. 

Geological Survey" should write to the U.S. Geological Survey, 582 

National Center, Reston, VA 22092.

Note.-Prices of Government publications listed in older catalogs, 

announcements, and publications may be incorrect. Therefore, the 

prices charged may differ from the prices in catalogs, announcements, 

and publications.