Mineral Resources of 

Eight Wilderness Study Areas 

Bordering Zion National Park, 

Washington and Kane Counties, Utah

U.S. GEOLOGICAL SURVEY BULLETIN 1746-E

Chapter E

Mineral Resources of 

Eight Wilderness Study Areas 

Bordering Zion National Park, 

Washington and Kane Counties, Utah

By R.E. VAN LOENEN, E.G. SABLE,

H.R. BLANK, JR., H.N. BARTON, and P.M. BRIGGS

U.S. Geological Survey

J.E. ZELTEN

U.S. Bureau of Mines

K.L COOK 

University of Utah

The wilderness study areas are Orderville Canyon, North Fork 

Virgin River, Deep Creek, Goose Creek Canyon, Beartrap 

Canyon, LaVerkin Creek Canyon, Taylor Creek Canyon, and 

Red Butte

U.S. CEO LOGICAL SURVEY BULLETIN 1746

MINERAL RESOURCES OF WILDERNESS STUDY AREAS SOUTHWESTERN UTAH
DEPARTMENT OF THE INTERIOR 

DONALD PAUL MODEL, Secretary

U. S. GEOLOGICAL SURVEY 

Dallas L Peck, Director

Any use of trade names in this report is for descriptive purposes only and 

does not imply endorsement by the U.S. Geological Survey or the 

U.S. Bureau of Mines.

UNITED STATES GOVERNMENT PRINTING OFFICE: 1989

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 eight wilderness study areas bordering Zion National 

Park, Washington and Kane Counties, Utah.

(Mineral resources of wilderness study areas southwestern Utah ; ch. E) 

(U.S. Geological Survey bulletin ; 1746-E) 

Bibliography: p. 

Supt. of Docs, no.: I 19.3:1746-E

1. Mines and mineral resources Utah Zion National Park Region.

2. Wilderness areas Utah Zion National Park Region. I. Van Loenen, 

Richard E. II. Series. III. Series: U.S. Geological Survey bulletin ; 1746-E. 

QE75.B9 no. 1746-E 557.3 s [553'.09792'48] 88-600386 

[TN24.U8]
STUDIES RELATED TO WILDERNESS 

Bureau of Land Management Wilderness Study Areas

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

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

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

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

This report presents the results of a mineral survey of the Orderville Canyon 

(UT-040-145), North Fork Virgin River (UT-040-150), Deep Creek (UT-040-146), 

Goose Creek Canyon (UT-040-176), Beartrap Canyon (UT-040-177), LaVerkin Creek 

Canyon (UT-040-153), Taylor Creek Canyon (UT-040-154), and Red Butte 

(UT-040-147) Wilderness Study Areas, Washington and Kane Counties, Utah.

CONTENTS

Abstract El 

Summary El

Character and setting El 

Identified resources E5 

Potential for undiscovered resources E6 

Introduction E6

Investigations by the U.S. Bureau of Mines E8 

Investigations by the U.S. Geological Survey E9 

Appraisal of identified resources E9

Mining and mineral exploration history E9 

Mines and prospects, and mining claims and leases E9 

Appraisal of sites examined E10 

Gypsum E10

Construction and industrial sandstone, sand, and gravel Ell 

Ornamental sand and sandstone Ell 

Limestone Ell 

Coal Ell

Iron concretions Ell

Assessment of potential for undiscovered resources E12 

Geology E12

Geologic setting E12 

Description of rock units E12 

Subsurface rocks E12 

Surface rocks E13

Jurassic rocks E13 

Cretaceous rocks E14 

Quaternary deposits E14 

Structure E15 

Geophysics E15

Gravity data E15 

Aeromagnetic data E15 

Aeroradiometric data E18 

Geochemistry E18 

Methods E18 

Results E19

Mineral and energy resources E19 

Oil and gas E19

Potential E20 

Metals E20

Silver E20 

Uranium E20 

Geothermal sources E21 

Coal E21

Potential E22 

Gypsum E22 

References cited E22 

Appendix E25

Contents
PLATE

[Plate is in pocket]

1. Maps showing identified resources, mineral and energy resource potential, and 

geology of the eight wilderness study areas, Washington and Kane Counties, 

Utah

FIGURES

1-5. Maps of the eight wilderness study areas showing:

1. Identified resources and resource potential E2

2. Location E4

3. Physiographic setting E5

4. Bouguer gravity contours E16

5. Aeromagnetic contours E17

TABLE

1. Summary of identified resources and resource potential for eight 

wilderness study areas bordering Zion National Park, Utah E3

VI Contents
MINERAL RESOURCES OF WILDERNESS STUDY AREAS-SOUTHWESTERN UTAH

Mineral Resources of 

Eight Wilderness Study Areas 

Bordering Zion National Park, 

Washington and Kane Counties, Utah

By R.E. Van Loenen, E.G. Sable, H.R. Blank, Jr., 

H.N. Barton, and P.M. Briggs 

U.S. Geological Survey

J.E. Zelten

U.S. Bureau of Mines

K.L Cook 

University of Utah

ABSTRACT

In 1986-87, the USGS (U.S. Geological Survey) and the 

USBM (U.S. Bureau of Mines) conducted a mineral resource 

appraisal of eight wilderness study areas bordering Zion 

National Park, Washington and Kane Counties, Utah. They 

are Orderville Canyon (UT-040-145), North Fork Virgin River 

(UT-040-150), Deep Creek (UT-040-146), Goose Creek 

Canyon (UT-040-176), Beartrap Canyon (UT-040-177), 

LaVerkin Creek Canyon (UT-040-153), Taylor Creek Canyon 

(UT-040-154), and Red Butte (UT-040-147). The study 

areas range in size from 35 to 3,320 acres. The identified 

resources and mineral and energy resource potential of the 

study areas are summarized on figure 1 and in table 1. 

Inferred subeconomic resources of gypsum are present in 

the Orderville Canyon, North Fork Virgin River, and Deep 

Creek study areas; inferred subeconomic resources of 

common-variety sandstone occur in all of the study areas; 

and inferred subeconomic resources of limestone occur in all 

but the Red Butte study area. All of the study areas have the 

following mineral and energy resource potential for these 

undiscovered resources: moderate potential for oil and gas, 

and low potential for all metals (including silver and uranium)

Manuscript approved for publication, August 10, 1988.

and geothermal sources. The Orderville Canyon, North Fork 

Virgin River, and Deep Creek study areas have a low energy 

resource potential for undiscovered coal; the other five study 

areas have no potential for undiscovered coal. Although the 

Orderville Canyon, North Fork Virgin River, and Deep Creek 

study areas have subeconomic resources of gypsum, they 

have no mineral resource potential for additional undiscovered gypsum; the other five study areas also have no 

potential for undiscovered gypsum.

SUMMARY

Character and Setting

The eight study areas are about 15-25 mi (miles) south 

of Cedar City in Washington and Kane Counties, Utah (fig. 2). 

Seven of the study areas are along a 15-mi segment of the 

northeastern boundary of Zion National Park, and the other 

study area lies along the southwestern boundary. The study 

areas are (counterclockwise around the northern half of the 

park) Orderville Canyon (1,750 acres), North Fork Virgin 

River (1,040 acres,, Deep Creek (3,320 acres), Goose Creek 

Canyon (89 acres), Beartrap Canyon (40 acres), LaVerkin 

Creek Canyon (440 acres), Taylor Creek Canyon (35 acres), 

and Red Butte (804 acres). The study areas, for the most part, 

are relatively small tracts of land administered by the BLM 

(U.S. Bureau of Land Management) and surrounded by

Eight Wilderness Study Areas Bordering Zion National Park E1
113 

37° 

30'

'12' 1 1 2°50'

TAYLOR 

CREEK 

CANYON 

(UT-040-1 54)1

37' 

17'

IRON COUNTY | 

WASHINGTON COUNTY

LAVERKIN CREEK

CANYON

(UT-040-153)

Kolob Reservoir

M/C

BEARTRAP CANYON 

(UT-040-177)

Blue Springs 

Reservoir

NORTH FORK 

VIRGIN RIVER 

(UT-040-1 50)

GOOSE CREEK^^ -T-| 

CANYON * { 

(UT-040-176) M/C

Zion

National

Park

5 MILES

ORDERVILLE 

CANYON 

(UT-040-145}

EXPLANATION OF IDENTIFIED RESOURCES AND MINERAL AND ENERGY RESOURCE POTENTIAL

[See table 1 for summary of identified resources and resource potential for each of the eight study areas. All eight study areas 

have a low mineral and energy resource potential for all metals (including silver and uranium) and geothermal sources, with certainty level D. The Orderville Canyon, North Fork Virgin River, and Deep Creek study areas have a low energy resource potential for coal, with certainty level D; the other five study areas have no potential for coal, with certainty level D. Although the 

Orderville Canyon, North Fork Virgin River, and Deep Creek study areas have identified resources of gypsum, they have no 

mineral resource potential for additional gypsum, with certainty level D; the other five study areas have no potential for gypsum, 

with certainty level D]

Area of identified resources of gypsum

Geologic terrane having a moderate energy 

resource potential for oil and gas, with 

certainty level C Applies to entirety of all 

eight study areas

Approximate boundary of wilderness 

study area

D

Certainty levels

Data indicate geologic environment and 

suggest level of resource potential

Data indicate geologic environment and 

resource potential but do not establish 

activity of resource-forming processes

Data clearly define geologic environment 

and level of resource potential, and indicate activity of resource-forming processes in all or part of study area

Figure 1. Identified resources and mineral and energy resource potential of the eight wilderness study areas, Washington and 

Kane Counties, Utah.

private, State, and National Park Service-administered land. 

The boundaries of the study areas are essentially all legal 

land nets; some were modified slightly to accommodate 

existing roads and topography.

Except for the Red Butte study area, the eight study 

areas are remarkably similar in geology and physiographic 

setting. The Red Butte study area consists of a prominent 

sandstone butte. Each of the other seven represents a part of

E2 Mineral Resources of Wilderness Study Areas Southwestern Utah
Table 1 . Summary of identified resources and resource potential for eight wilderness study areas bordering Zion National 

Park, Utah

Wilderness study area Acres Identified resources Resource potential

Orderville Canyon 

(UT-040-145).

1,750

North Fork Virgin River 1,040 

(UT-040-150).

Deep Creek 3,320 

(UT-040-146).

Goose Creek Canyon 89 

(UT-040-176).

Beartrap Canyon 40 

(UT-040-177).

LaVerkin Creek Canyon 440 

(UT-040-153).

Taylor Creek Canyon 35 

(UT-040-154).

Red Butte 804 

(UT-040-147).

Inferred subeconomic resources of 

gypsum (about 20 million tons), 

sandstone, and limestone.

Inferred subeconomic resources of 

gypsum (about 20 million tons), 

sandstone, and limestone.

Inferred subeconomic resources of 

gypsum, sandstone, and 

limestone.

Inferred subeconomic resources of 

sandstone and limestone.

Inferred subeconomic resources of 

sandstone and limestone.

Inferred subeconomic resources of 

sandstone and limestone.

Inferred subeconomic resources of 

sandstone and limestone.

Inferred subeconomic resources of 

sandstone.

Moderate resource potential for oil and gas. 

Low resource potential for metals, geothermal

sources, and coal. 

No resource potential for additional gypsum.

Moderate resource potential for oil and gas. 

Low resource potential for metals, geothermal

sources, and coal. 

No resource potential for additional gypsum.

Moderate resource potential for oil and gas. 

Low resource potential for metals, geothermal

sources, and coal. 

No resource potential for additional gypsum.

Moderate resource potential for oil and gas. 

Low resource potential for metals and

geothermal sources. 

No resource potential for coal and gypsum.

Moderate resource potential for oil and gas. 

Low resource potential for metals and

geothermal sources. 

No resource potential for coal and gypsum.

Moderate resource potential for oil and gas. 

Low resource potential for metals and

geothermal sources. 

No resource potential for coal and gypsum.

Moderate resource potential for oil and gas. 

Low resource potential for metals and

geothermal sources. 

No resource potential for coal and gypsum.

Moderate resource potential for oil and gas. 

Low resource potential for metals and

geothermal sources. 

No resource potential for coal and gypsum.

a major canyon near the headwaters of drainages that flow 

through Zion National Park, all of which are part of the Virgin 

River system.

The study areas are located on the Kolob Terrace along 

the southwest margin of the Colorado Plateau physiographic 

province (fig. 3). The Kolob Terrace is a "step" in the "Grand 

Staircase," a name applied to this region because the skyline 

resembles a staircase. The landform is marked by major 

topographic terraces that descend nearly 6,0X30 ft (feet) from 

northeast to southwest into Arizona. The Kolob Terrace 

extends for about 30 mi between Cedar City and Orderville. 

The Kolob Terrace is bordered by the Hurricane fault zone to 

the west and by the Sevier fault zone to the east. The study 

areas are between 5,000 and 7,800 ft in elevation. Terrain 

within and surrounding the study areas is quite rugged; 

some of the canyons are over 1,000 ft deep, and Red Butte 

rises nearly 800 ft above a lower terrace of the Kolob Plateau.

Sedimentary rock of Jurassic and Cretaceous ages 

(see geologic time chart in Appendix) is exposed in that part 

of the Kolob Terrace containing the study areas (pi. 1). These 

exposed rock units include the Kayenta Formation, Navajo 

Sandstone, Temple Cap Sandstone, Carmel Formation,

Dakota Formation, Tropic Shale, and Straight Cliffs 

Sandstone. The Navajo is the major rock unit in all the study 

areas, the Kayenta is exposed only at Red Butte, and the 

Dakota and Tropic units occur in the Orderville Canyon, 

North Fork Virgin River, and Deep Creek study areas. Basalt 

flows of Quaternary age cover parts of the Deep Creek study 

area.

The Navajo and Temple Cap, for the most part, form the 

canyon walls, and the limestone member of the Carmel 

occupies timber-covered flats or benches above the 

canyons. The banded and gypsiferous members of the 

Carmel, the Winsor Member of the Carmel, and the Dakota 

and the Tropic, in general, underlie mostly brush-covered 

slopes above the flats. The Kayenta forms the lower part of 

Red Butte and the Straight Cliffs is a ledge former above the 

Tropic.

The seven study areas along the northeastern part of 

the park can be reached by traveling north on an unpaved 

road that leaves State Highway 9 just east of the park (fig. 2). 

The Orderville Canyon study area is about 8 mi north on this 

road, and about 5 mi farther the road crosses the North Fork 

of the Virgin River. A popular hiking trail begins there and

Eight Wilderness Study Areas Bordering Zion National Park E3
112°38'

 . ... DEEP CREEK 

Kolob ^.

37°05'

Figure 2. Location of the eight wilderness study areas (shaded) bordering Zion National Park, Washington and Kane 

Counties, Utah. Four nearby wilderness study areas are also shown (Canaan Mountain, Parunuweap Canyon, Spring Creek 

Canyon, and The Watchman). Wilderness study area boundaries are approximate. Dashed lines indicate unpaved roads. Note: 

(1) The formal names of two creeks are as follows: Bear Trap Creek, La Verkin Creek. (2) The following topographic features 

are not formally named: canyon of Goose Creek, canyon of La Verkin Creek, canyon of Taylor Creek.

follows the river through the North Fork Virgin River study 

area and through Zion National Park. The east side of the 

Deep Creek study area and the northern part of the North 

Fork Virgin River study area are served by a jeep trail leading 

west where the main road crosses the North Fork of the 

Virgin River. Several jeep trails and secondary roads lead 

both east and west in the vicinity of Kolob Reservoir to the 

western parts of the Deep Creek, Goose Creek Canyon, and 

Beartrap Canyon study areas, and to the eastern part of the

LaVerkin Creek Canyon study area. Access to the Taylor 

Creek Canyon study area and the western parts of the 

LaVerkin Creek Canyon study area is provided from the north 

by a gravel road starting near Kanarraville, Utah, and ending 

near the study areas.

The Red Butte study area is easily accessible from the 

paved road that begins at Virgin, Utah, and continues north 

through the Kolob (northwestern) part of Zion National Park.

E4 Mineral Resources of Wilderness Study Areas Southwestern Utah
112°35'

37°00'

Figure 3. Physiographic setting of the eight wilderness study areas and vicinity, Utah. See figure 2 for locations of the 

eight study areas.

Identified Resources

An extensive gypsum bed in the Jurassic Carmel 

Formation (gypsiferous member) occurs in the Orderville 

Canyon, North Fork Virgin River, and Deep Creek study

areas. Inferred subeconomic resources of at least 20 million 

tons of surface-minable gypsum occur in both the Orderville 

Canyon and North Fork Virgin River study areas (fig. 1); 

resources of gypsum were not calculated for the Deep Creek 

study area because of poor exposures.

Eight Wilderness Study Areas Bordering Zion National Park E5
Inferred subeconomic resources of common-variety 

sandstone occur in all of the study areas, and inferred 

subeconomic resources of limestone occur in all of the study 

areas except for Red Butte. Because these commodities 

have a low unit value and ample supplies of similar materials 

are available elsewhere in the region closer to transportation 

centers and markets, it is doubtful that these deposits will be 

developed in the foreseeable future.

Formations that host uranium deposits elsewhere on 

the Colorado Plateau have no evidence of near-surface 

uranium-mineralized rock in the study areas.

Coal was mined to the north and east of the study 

areas, but coal-bearing formations have not been tested in 

the study areas. There has been no exploration by drilling for 

oil and gas in the study areas.

Potential for Undiscovered Resources

The formations exposed in the study areas are not 

known to contain major ore deposits or energy sources 

anywhere in the region, and geologic mapping and geochemical sampling did not reveal any anomalous mineral 

concentrations. Geophysical data did not indicate any 

anomalies in the study areas.

The eight wilderness study areas have a moderate 

energy resource potential for oil and gas. The stratigraphic 

setting of the study areas is similar to that of the nearby Virgin 

oil field, located about 2 mi northeast of Virgin, Utah. Since 

1907, the Virgin field has produced about 200,000 barrels of 

oil from structural and stratigraphic traps in the Timpoweap 

Member of the Triassic Moenkopi Formation and probably 

from the Permian Kaibab Limestone. These and other 

favorable Paleozoic reservoir rocks occur more than 2,500 ft 

beneath the study areas.

The study areas have a low mineral resource potential 

for undiscovered resources of all metals, including silver and 

uranium. The Moenave and Chinle Formations, which respectively contain silver and uranium elsewhere in the region, are 

present beneath the study areas but at depths ranging from 

500 to over 2,000 ft. The paucity of mineral deposits in these 

units in southwestern Utah and their depth beneath the study 

areas suggest a low potential for the discovery of metals 

within the study areas.

The study areas lie in terrane defined as having low 

terrestrial heat flow (Muffler, 1978) and therefore have a low 

energy resource potential for geothermal sources.

Although the study areas are partly within the Kolob 

coal field, the important coal-bearing beds of the Cretaceous 

Tropic Shale are not present. The Orderville Canyon, North 

Fork Virgin River, and Deep Creek study areas have a low 

energy resource potential for coal in the lower parts of the 

Tropic; the other five study areas do not contain Cretaceous 

rocks and therefore have no potential for coal.

The gypsiferous member of the Carmel Formation is 

present at the surface in and near the Orderville Canyon, 

North Fork Virgin River, and Deep Creek study areas and is 

also present in the subsurface adjacent to these study areas. 

These three study areas have inferred subeconomic 

resources of gypsum, and no mineral resource potential for

additional gypsum. The gypsiferous member is not present 

in any of the other five study areas, and they have no 

potential for gypsum.

INTRODUCTION

The eight wilderness study areas border Zion 

National Park in Washington and Kane Counties in the 

canyonlands of southwest Utah (fig. 2). The study areas 

are, counterclockwise around the northern one-half 

of the park, Orderville Canyon (UT-040-145), North 

Fork Virgin River (UT-040-150), Deep Creek 

(UT-040-146), Goose Creek Canyon (UT-040-176), 

Beartrap Canyon (UT-040-177), LaVerkin Creek 

Canyon (UT-040-153), Taylor Creek Canyon 

(UT-040-154), and Red Butte (UT-040-147). Due to 

their relatively small sizes and similar geologic settings 

and resource potentials, the eight wilderness study areas 

are combined in this report, and unless reference is made 

to a specific study area (or areas), all eight are here 

referred to as the study areas. In addition to these study 

areas, four other study areas border Zion National Park 

(fig. 2). The mineral resources of the Canaan Mountain 

(UT-040-143), The Watchman (UT-040-149), and the 

Parunuweap Canyon (UT-040-230) study areas have 

been reported on by Van Loenen and others (1988a, b), 

and work on the Spring Creek Canyon (UT-040-148) 

study area is in progress.

The boundaries of the eight study areas are 

essentially all elements of legal land nets defining tracts 

of BLM-administered land surrounded by State, private, 

and National Park Service-administered land. Land net 

boundaries of the Deep Creek and Goose Creek Canyon 

study areas were slightly modified to exclude land 

containing existing roadways, and the Orderville Canyon 

boundary is defined in part by topography.

The salient features within all the study areas, 

except Red Butte, are deep canyons, remarkably similar 

in geology and physiography, near the headwaters of the 

major Virgin River tributaries that flow through Zion 

National Park. Rocks exposed in the study areas are 

sedimentary rocks of the Jurassic Kayenta Formation, 

Navajo Sandstone, Temple Cap Sandstone, and Carmel 

Formation, and the Cretaceous Dakota Formation and 

Tropic Shale. Quaternary basalt flows cover parts of the 

Deep Creek study area. The Navajo and Temple Cap, for 

the most part, form the canyon walls, and limestone of 

the Carmel occupies timber-covered flats or benches 

above the canyons. The banded and gypsiferous 

members of the Carmel, the Winsor Member of the 

Carmel, and the Dakota and the Tropic in general form 

steeper brush-covered slopes above the flats. Red Butte 

is an erosional remnant of Navajo and Kayenta rocks that 

support little vegetation.

E6 Mineral Resources of Wilderness Study Areas Southwestern Utah
The study areas are located near the southwest 

margin of the Colorado Plateau physiographic province. 

This region of southwest Utah and northern Arizona is 

often referred to as the "Grand Staircase." Landforms 

here consist of terraces or "steps" that descend nearly 

6,000 ft from the high plateaus of southern Utah 

southwest into Arizona. The terraces represent erosional 

levels in a thick section of heterogeneous rock. This 

erosion began in Cenozoic time and continues in the 

present at a relatively rapid pace. The study areas are on 

the Kolob Terrace, a "step" in the staircase at about 

7,000-ft elevation. The Kolob Terrace is terminated on 

the west by the Hurricane fault zone and on the east by 

the Sevier fault zone (fig. 3).

There has been no mining or evidence of 

prospecting in any of the study areas. Stock grazing and 

limited logging activities were carried out in some parts 

of the study areas in the past, but little activity was 

evident at the time of this study. Except for the Red Butte 

study area, the study areas are located in remote areas 

and access to them is difficult.

The Orderville Canyon Wilderness Study Area 

contains 1,750 acres along the east boundary of Zion 

National Park in Washington County, Utah. Major 

topographic features include parts of Orderville Canyon, 

Esplin Gulch, and Birch Hollow. Elevations range from 

5,200 ft in Orderville Canyon at the park boundary to 

6,600 ft in the southeast. The study area is about 8 mi 

north of State Highway 9 near a county road. A jeep trail 

leading to the west off the county road south of Birch 

Hollow provides access to the southern part of the study 

area. This trail ends near the site of an old sawmill where 

Ponderosa pine was timbered in the past. Jeep trails 

serve parts of the area north of Orderville Canyon. All of 

the trails in the vicinity are suitable for vehicular use only 

under dry conditions. They are used mainly for livestock 

grazing operations and hunting. Hunting lodges are 

along the main county road just south of the study area, 

and an abandoned uranium mine is located about ¥2 mi 

east of the study area.

The North Fork Virgin River Wilderness Study 

Area contains 1,040 acres along the Kane County line 

about 2 mi north of the Orderville Canyon study area. It 

shares part of its western boundary with Zion National 

Park. The main topographic feature within the study area 

is a 1-mi stretch of canyon cut by the North Fork of the 

Virgin River, which dissects the southern quarter of the 

study area. The study area can be reached by continuing 

north on the county road beyond Orderville Canyon to 

the North Fork of the Virgin River and hiking down the 

river to the study area. A popular hiking trail follows the 

river through the study area into the park, through the 

North Fork "Narrows," and ending at the southern park 

entrance. A jeep trail heading west off the main road 

north of the river transects the northwestern part of the

study area. Topographic relief in the study area is about 

1,500 ft, from the river bottom at the park boundary at 

about 5,400 ft to over 6,800 ft in brush-covered slopes 

along the northern boundary of the study area.

The Deep Creek Wilderness Study Area, the 

largest of the eight study areas, contains 3,320 acres in 

the northeastern part of Washington County. It is about 

V2 mi west of the North Fork Virgin River study area. 

Salient features of the study area include spectacular 

canyons cut by sections of Kolob Creek, Deep Creek, and 

the North Fork of the Virgin River. These three canyons 

merge about 1 mi south of the study area in Zion 

National Park. The canyon cut by Deep Creek is more 

than 1,000 ft deep at the park boundary; the elevation at 

the creek is 5,000 ft. The highest point in the study area 

is about 7,000 ft along the northeast border. Little activity 

was seen in and around the study area, but land above the 

canyons was used in the past for grazing and timbering 

and some land appears to have been cultivated. The study 

area extends 3 mi north of the park boundary to include 

an area of basalt flows, and a volcanic cinder cone lies 

just north of the border.

Access to the Deep Creek study area from the east 

is gained by continuing west beyond the North Fork 

Virgin River study area. This road follows along part of 

the Deep Creek study area's eastern boundary and ends 

at an abandoned sawmill site. Other roads in this area 

have been closed at the study area's boundary. Access is 

much easier from the west, but most of the roads there 

are on private land. The study area is from 6 to 10 mi east 

of Kolob Reservoir. Several roads heading east from the 

reservoir go as far as Deep Creek. There are no 

established hiking trails in the study area, and access into 

the canyons is difficult except at their uppermost parts.

The Goose Creek Canyon Wilderness Study Area 

contains 89 acres and is about 1 mi west of the Deep 

Creek study area in the northeastern part of Washington 

County. It is bounded on the west and south by Zion 

National Park. Goose Creek drains to the southeast and 

empties into the North Fork of the Virgin River about 4 

mi into the park. Relief in the study area exceeds 1,000 ft; 

Goose Creek at the park boundary is at about 5,900-ft 

elevation. The study area is accessible from a main road 

that serves and continues past Lava Point Lookout in the 

park south of Kolob Reservoir. A right fork off this road 

ends within the study area; the main road continues along 

the northern boundary of the study area. The area of 

private land between Kolob Reservoir and Goose Creek 

Canyon study area is currently being developed as sites 

for summer homes.

The Beartrap Canyon Wilderness Study Area 

consists of 40 acres along the park boundary 6 mi 

northwest of the Goose Creek Canyon study area in 

Washington County. This study area is in very rugged 

terrain. Two deep canyons tributary to the canyon of

Eight Wilderness Study Areas Bordering Zion National Park E7
Bear Trap Creek join near the center of this small tract, 

and relief, which begins at 6,600-ft elevation in the creek 

bottom, is more than 1,000 ft at the study area boundary. 

There are no roads or trails nearby and entering the park 

from the study area is difficult. A road west from Blue 

Springs Reservoir ends about 2 mi south of the study 

area, and the road along the west side of Kolob Reservoir 

is no closer than 2 mi from the study area. The Beartrap 

Canyon study area is bounded on three sides by private 

land and on the west by the park.

The LaVerkin Creek Canyon Wilderness Study 

Area contains 440 acres in Washington County about 3 

mi west of Kolob Reservoir and 2 mi northwest of the 

Beartrap Canyon study area. La Verkin Creek flows 

southwest through the study area across Zion National 

Park and empties into the Virgin River at La Verkin, 

Utah. Salient features in the study area include a 2-mi 

stretch of canyon cut by La Verkin Creek and part of 

Bear Canyon, a tributary to La Verkin Creek. Elevations 

range from about 5,800 ft in the creek bottom at the park 

boundary to 7,000 ft in the northwest corner. The study 

area is bounded by private land, except the southern 

boundary, which is shared with the park. The study area 

can be reached from the east by taking a jeep trail that 

heads west from the northwestern part of Kolob 

Reservoir and passes by Birch Spring. The La Verkin 

Creek hiking trail, which begins near Birch Spring, 

descends into Willis Creek and joins La Verkin Creek 

about 1 mi south of the study area in the park. Access to 

the west side of the study area is provided by taking a 

gravel road north of Kanarraville, Utah, to the east that 

climbs over the Hurricane Cliffs and heads south. Travel 

on this road is mainly through private land restricted by 

locked gates. Several trails leading off this road to the 

east end near the study area boundary. Stock grazing is 

currently active in and near the LaVerkin Creek Canyon 

study area.

The Taylor Creek Canyon Wilderness Study Area 

contains 35 acres at the head of the middle fork of Taylor 

Creek in northeast Washington County. This study area, 

the smallest of the study areas, is bounded on the west by 

Zion National Park, and is made up almost entirely of a 

600-ft-deep steep-walled canyon. The upper rim of the 

canyon, at about 7,800-ft elevation, provides an excellent 

view of the canyon of Taylor Creek and a panoramic view 

of the park to the south. There is no access into the 

canyon from within the study area. The study area is 

located about 15 mi south of Cedar City, Utah, and about 

2 mi west of the LaVerkin Creek Canyon study area. The 

Taylor Creek Canyon study area can be visited by taking 

the road from near Kanarraville, Utah, that serves the 

LaVerkin Creek Canyon study area. This road passes 

along the northeast corner of the Taylor Creek Canyon 

study area and ends at an abandoned cabin site southwest 

of the study area.

The Red Butte Wilderness Study Area contains 

804 acres along the southwest side of Zion National Park. 

It is located in northeast Washington County about 12 mi 

north of Virgin, Utah. Red Butte is a prominent sandstone butte and a landmark in the region. It rises more 

than 1,000 ft above the lower Kolob Plateau and more 

than 2,000 ft above Smith Mesa. Smith Mesa, southwest 

of Red Butte, is the next "step" below Kolob Terrace. 

Red Butte can be visited by taking a gravel road leading 

to the west from the paved highway between Virgin, 

Utah, and the upper Kolob Plateau. Several roads 

serving Smith Mesa from near Virgin, Utah, pass close to 

the southwest base of Red Butte. Livestock grazing is 

active near the study area, and land at the base of Red 

Butte was cultivated in the past. Smith Mesa is a large, 

active agricultural area.

This report presents an evaluation of the mineral 

endowment (identified resources and mineral resource 

potential) of the study areas and is the product of several 

separate studies by the USBM and the USGS. Identified 

resources are classified according to the system of the 

USBM and USGS (1980), which is shown in the 

Appendix of this report. Identified resources are studied 

by the USBM. Mineral resource potential is the likelihood of the occurrence of undiscovered metals and 

nonmetals, industrial rocks and minerals, and of undiscovered energy sources (coal, oil, gas, oil shale, and 

geothermal sources). It is classified according to the 

system of Goudarzi (1984) and is shown in the Appendix. 

The potential for undiscovered resources is studied by 

the USGS.

Investigations by the 

U.S. Bureau of Mines

The USBM's field investigation of the study areas 

was preceded by a review of various sources of 

information, including published and unpublished literature and USBM files, regarding the geology and mineral 

resources of the region. BLM files in Cedar City and Salt 

Lake City, Utah, were reviewed for mining claim and oil, 

gas, coal, and geothermal lease information. BLM geologists, National Park Service personnel at Zion National 

Park, and local residents were interviewed regarding 

minerals information in the region.

Field investigation, consisting of a search for mines, 

prospects, and mineralized areas in or within 1 mi of 

the study areas, was conducted in September 1986 and 

May 1987. A total of 32 rock samples was taken from 

outcrops and various workings. These samples were 

analyzed by Skyline Labs, Inc., Wheat Ridge, Colo. One 

panned-concentrate sample and one stream-sediment 

sample also were taken. These samples were analyzed by 

Chemex Labs, Inc., Sparks, Nev.

E8 Mineral Resources of Wilderness Study Areas Southwestern Utah
Six sandstone samples were taken and all were 

analyzed for gold, silver, and copper by atomic absorption spectrometry. Whole-rock analyses for major 

elements were performed on all six sandstone samples, 

and five were analyzed for 31 elements by optical 

emission spectrography. Selected samples were analyzed 

for uranium by fluorimetry and for vanadium by inductively coupled plasma-atomic emission spectrography.

Whole-rock analyses were performed on six 

limestone and eight gypsum samples taken from outcrops. All six limestone samples and three of the gypsum 

samples were analyzed for 31 elements by optical 

emission spectrography.

Twelve rock samples taken from uranium mines 

were analyzed for gold, silver, and copper by atomic 

absorption spectrometry, for uranium by fluorimetry, for 

vanadium by inductively coupled plasma-atomic emission spectrography, and for 31 elements by optical 

emission spectrography.

The panned-concentrate and stream-sediment 

samples were analyzed by fire assay for gold and by 

inductively coupled plasma-atomic emission spectrography for 32 elements.

Sample descriptions and analytical results are 

presented in Zelten (1987). Additional information is 

available from the USBM, Intermountain Field Operations Center, Building 20, Denver Federal Center, Denver, CO 80225.

Investigations by the 

U.S. Geological Survey

The assessment of the potential for undiscovered 

resources in the eight study areas is based largely on the 

geologic setting, geophysical data, and geochemical data 

of the study areas, and on the production history of 

similar rock units in southwestern Utah. Field work for 

these studies was done in parts of June and September 

1986, and June, September, and October 1987.

Geologic maps at 1:24,000 scale were compiled for 

the study areas using aerial photographs. Pertinent 

literature on the geology of the region includes a comprehensive report on the geology of the Zion National Park 

region (Gregory, 1950) and an overall geologic perspective with diagrammatic illustrations of geologic 

history and stratigraphic units of Utah (Hintze, 1973). 

Areal geologic reports and maps for various parts of the 

region have been prepared by Cashion (1967a), Sargent 

and Philpott (1985, 1987), and Hamilton (1978). Stratigraphic studies include a discussion of lower and middle 

Mesozoic units (Wilson and Stewart, 1967; Cashion, 

1967b), and a review and interpretation of the Navajo 

Sandstone and other Jurassic units (Peterson and 

Pipiringos, 1979). A recent comprehensive report on the

geologic history and landforms of Zion National Park by 

Hamilton (1984) is oriented towards both professional 

and nonprofessional audiences.

Geophysical studies included gravity, aeromagnetic, and aeroradiometric surveys. Some new gravity 

stations were established, and data obtained from them 

were used in this report. Other gravity data were 

provided by K.L. Cook of the University of Utah. Aeromagnetic and aeroradiometric data for the region are 

available from the NURE (National Uranium Resource 

Evaluation) program and a published aeromagnetic map 

of the State of Utah (Zietz and others, 1976).

Stream-sediment samples were collected and analyzed in the geochemical survey. Analytical data and 

sample locations are by Bullock and others (in press).

Information used in assessing the potential for oil 

and gas resources is taken largely from Ryder (1983) and 

Molenaar and Sandberg (1983). Other sources of data 

are Bahr (1963), who described the Virgin oil field, 

Oakes and others (1981), who evaluated energy 

resources for the study areas, and the U.S. Department 

of Energy (1979), who evaluated uranium resources for 

the region. Data for the Kolob coal field are from 

Doelling and Graham (1972).

APPRAISAL OF IDENTIFIED RESOURCES

By J.E. Zelten

U.S. Bureau of Mines

Mining and Mineral Exploration History

No mines, prospects, or patented claims are in the 

study areas, nor are the study areas included in any 

mining district. The nearest mining district is the Silver 

Reef (Harrisburg) district, about 14 mi southwest of Red 

Butte. Between 1875 and 1910, over $8,000,000 of highgrade silver ore (over 7,000,000 oz (ounces) silver), with 

small amounts of associated copper, uranium, and 

vanadium, was produced from the Springdale Sandstone 

Member (formerly referred to informally as the Silver 

Reef sandstone) of the Moenave Formation in this 

district (Heyl, 1978; Proctor, 1953). In 1950, 8.68 tons 

of ore averaging 0.56 percent uranium was shipped 

(Gregory, 1950). The Moenave has not been tested in the 

study areas to determine if similar deposits are present.

Mines and Prospects, and Mining Claims 

and Leases

Unpatented lode claims and oil and gas leases and 

lease applications cover parts of several of the study 

areas. Two oil fields are within 8 mi of Red Butte.

Eight Wilderness Study Areas Bordering Zion National Park E9
A block of more than 300 unpatented lode claims 

just east of and slightly overlapping the southeastern 

boundary of the Orderville Canyon study area has been 

staked for uranium in the basal conglomerate unit of the 

Dakota. About Vi mi east of the Orderville Canyon study 

area several abandoned uranium mines and prospects on 

these claims were mapped and sampled (Zelten, 1987). 

The conglomerate unit is poorly cemented and consists 

of interbedded conglomerate, sandstone, and claystone; 

an underlying dark-gray shale unit was exposed in one 

adit. Silicified wood and carbonaceous or coaly streaks 

and lenses are common. Much of the conglomerate and 

sandstone are heavily stained by limonite. Gamma-ray 

spectrometer readings at the workings varied from about 

250 to 13,300 cps (counts per second); background for 

the area was 150-250 cps. Carnotite and other uraniumoxide minerals are visible on outcrops and weathered 

surfaces. In 1950, 8.5 tons of ore, assaying 0.16 percent 

uranium trioxide (U3 O8 ), was shipped from the workings 

(Beroni and others, 1953). No uranium-vanadium 

resources were calculated at these workings because the 

metal concentrations were discontinuous. No evidence 

was found that similar deposits occur in the Orderville 

Canyon study area.

Eight unpatented lode claims, mostly within the 

northern part of the North Fork Virgin River study area, 

were apparently staked for gypsum in the Carmel 

Formation although there has been no exploration work.

A block of 70 unpatented lode claims partially 

overlaps the northwestern part of the Red Butte study 

area. These claims were staked for uranium and vanadium in the Moenave Formation, and currently (1987) 

are being prospected for uranium, vanadium, copper, 

and silver. A panned-concentrate sample and a streamsediment sample were taken from near the northwestern 

study area boundary to determine if uranium, vanadium, 

copper, or silver were present; none was present in 

unusually high concentrations (Zelten, 1987).

Oil and gas leases and lease applications cover all 

of the Beartrap Canyon study area and most of the Red 

Butte study area. Oil and some gas have been produced 

from two fields in this part of Utah, the Virgin field and 

the Anderson Junction field, about 8 mi to the south and 

southwest, respectively, of Red Butte.

In the Virgin field, oil and small amounts of gas 

were produced intermittently from the Timpoweap (Sinbad) Member of the Moenkopi Formation (Bahr, 1963; 

Irwin, 1976) and possibly the Kaibab Limestone. Total 

oil production from this field between 1907 and 1970 was 

over 200,000 barrels (Stowe, 1972). Several test holes 

drilled to various depths below the Moenkopi within 15 

mi east of the Orderville Canyon study area and one hole 

drilled about 7 mi south of Red Butte were dry and 

abandoned. Approximately 1,380 barrels of oil were 

produced from the Pennsylvanian Callville Limestone in

the Anderson Junction field between 1968 and 1970. The 

field was shut in in 1971. Neither the Moenkopi nor the 

Callville have been tested in the study areas to determine 

if they contain oil or gas. (See Peterson, 1974).

Appraisal of Sites Examined

Inferred subeconomic resources in the study areas 

include gypsum, common-variety sandstone, and limestone. Small, scattered accumulations of sand and gravel 

occur in several of the study areas. Coal was mined to the 

north and east of the study areas. Iron concretions, often 

sold in rock shops, weather out of the Navajo Sandstone 

in scattered locations throughout the region.

Gypsum

Inferred subeconomic resources of gypsum occur 

in the gypsiferous member of the Carmel Formation in 

the Orderville Canyon, North Fork Virgin River, and 

Deep Creek study areas. Averaging about 30-60 ft thick 

and dipping about 1° NE., this gypsum bed can be 

followed for many miles to the northwest and southeast.

Examination and sampling of the gypsum from this 

bed at various localities have shown its quality to be 

consistent (Zelten, 1987). The gypsum is sufficiently pure 

to have value for building materials, fertilizer, cement, 

and many other products. Gypsum is a low-unit-value, 

high-bulk commodity, and the single most important 

factor in evaluating a deposit is its proximity to markets. 

Deposits of high quality and commercial size are widespread in the United States, and development largely 

depends on the accessibility and the demand for gypsum 

products in the region near the deposit. (See Appleyard, 

1983; Bates, 1969; Moyer, 1939.) Because of the absence 

of a nearby market and the presence of large, minable 

deposits elsewhere in Utah nearer to markets, the 

gypsum in the study areas is not likely to be developed at 

this time or in the foreseeable future.

Gypsum in the Carmel crops out continuously for 

almost 2 mi in the vicinity of the southeastern part of the 

Orderville Canyon study area (pi. 1, map D). Inferred 

subeconomic resources of about 30 million tons of 

surface-minable gypsum occur in the study area and 

within Y* mi of its boundary. This estimate is based on an 

average thickness of 50 ft and an assumed continuity of 

gypsum back from the outcrop, and is limited to gypsum 

covered by no more than 100 ft of overburden. Of this 

tonnage at least 20 million tons lie within the study area. 

Any mining would be more likely to occur in the more 

flat-lying areas south and east of Orderville Canyon 

where larger quantities of gypsum are more accessible.

Gypsum in the Carmel crops out intermittently for 

about 2 mi along steep drainages in the vicinity of the 

northern part of the North Fork Virgin River study area

E10 Mineral Resources of Wilderness Study Areas Southwestern Utah
(pi. 1, map B). Inferred subeconomic resources of about 

30 million tons of surface-minable gypsum occur in the 

study area and within 1A mi of its boundary. This estimate 

is based on an average thickness of 50 ft and an assumed 

continuity of gypsum back from the outcrop, and is 

limited to gypsum covered by no more than 100 ft of 

overburden. Of this tonnage at least 20 million tons lie 

within the study area. Any mining would be more likely 

to occur in the more flat-lying areas to the northeast and 

outside the study area where larger quantities of gypsum 

are more accessible.

Gypsum in the Carmel extends for about 2 mi 

across the northeastern part of the Deep Creek study 

area (pi. 1, map B). Inferred subeconomic resources of 

gypsum occur in the study area, but tonnages were not 

calculated because the unit is poorly exposed.

Construction and Industrial Sandstone, 

Sand, and Gravel

Inferred subeconomic resources of sandstone 

underlie all of the study areas and crop out over about 70 

percent of their combined surface areas. Sand and small 

amounts of gravel are present on the uplands and in the 

drainages of the Orderville Canyon and Deep Creek 

study areas. These commodities could be used locally for 

construction purposes. Because these are high-volume, 

low-unit-value commodities and because transportation 

costs are a major factor in determining the value of a 

deposit, the remoteness and relative inaccessibility of 

these deposits make their development unlikely for other 

than local use. Some of the sandstone units could be used 

as bulk aggregate, but most of the rock is too friable for 

this purpose. Large deposits of material suitable for 

construction purposes and closer to transportation 

systems and markets are sufficient to supply present and 

projected future local use.

Industrial (silica) sand is used mostly in the glassmaking, foundry, and abrasive industries. The sand 

should consist mainly of quartz grains and must be free of 

contaminants; rigid specifications of purity, silica content, 

and size must be met. (See Coope and Harben, 1977; 

Davis and Tepordei, 1985.) Whole-rock analyses of 

sandstone samples from the study areas indicate that the 

sand contains either too little silica or too much iron 

oxide to have industrial value (Zelten, 1987).

Ornamental Sand and Sandstone

Bleached or stained sand from the study areas 

could be used for sand painting and other decorative 

uses. The most desirable sand deposits are those that 

contain unusual as well as multiple colors in one locality, 

such as at one mine near Kanab, Utah. Sand in and near

the study areas is not of unusual color. Large deposits 

near Kanab are closer to current markets and are 

sufficient to supply anticipated present and future 

demands.

Picture rock is crossbedded sandstone that has 

been stained by iron oxide, resulting in interesting and 

unusual designs. The best known deposits are in the 

Navajo and the Chinle near Kanab. Picture rock is often 

cut into slabs that are sold as ornaments or wall hangings, 

or it may be ground into spheres or other decorative 

shapes. Iron stains and liesegang bands (secondary 

nested rings or bands caused by periodic or rhythmic 

precipitation of mostly iron oxides within a fluidsaturated rock) are common in the crossbedded Navajo 

Sandstone in the study areas, but no picture rock was 

observed and no such resources identified.

Limestone

An inferred subeconomic resource of limestone 

suitable for agricultural purposes exists in the Carmel 

Formation in all of the study areas except Red Butte. 

Crushed limestone also could be used locally for aggregate, but sufficient quantities of similar material are 

available closer to markets. Because the Carmel 

possesses no unique characteristics that would make it 

more desirable than limestone present elsewhere in the 

region and closer to markets, development of this 

material is unlikely.

Coal

Coal has been mined from the Tropic Shale in the 

Kolob coal field, the southwestern limit of which has 

been mapped to within 1 mi of the Orderville Canyon, 

North Fork Virgin River, LaVerkin Creek Canyon, and 

Taylor Creek Canyon study areas (Cashion, 1961). Coalbearing units may underlie landslide material in the 

northernmost parts of the North Fork Virgin River and 

Deep Creek study areas and the southeastern corner of 

the Orderville Canyon study area, but these areas have 

not been tested for coal. The coal-bearing units are not 

present in the other five study areas.

A 6-ft-thick carbonaceous shale unit of the Tropic 

is exposed in the northern part of the North Fork Virgin 

River study area in a road cut and in a drainage. 

Proximate and ultimate analyses of a sample of this shale, 

taken 2 ft in from the outcrop, showed it to be of poor 

quality with no commercial use (Zelten, 1987). It is not 

known if this carbonaceous shale grades laterally into 

coal in the subsurface. Coal resources were not identified 

in any of the three study areas mentioned previously and 

the Tropic is absent in the other five study areas.

Iron Concretions

Rounded to irregularly shaped iron concretions 

commonly weather out of the Navajo Sandstone. Those

Eight Wilderness Study Areas Bordering Zion National Park E11
with unusual shapes, coloration, or internal construction 

are sometimes collected and sold as curiosities. Most of 

the popular collecting sites are east of Orderville Canyon. 

Concretions found in the Navajo in the study areas are 

typical of those that are abundant and readily available in 

much of the region.

ASSESSMENT OF POTENTIAL FOR 

UNDISCOVERED RESOURCES

By R.E. Van Loenen, E.G. Sable, 

H.R. Blank, Jr., H.N. Barton, and 

P.M. Briggs 

U.S. Geological Survey

K.L. Cook 

University of Utah

Geology

Geologic Setting

The study areas are on the Kolob Terrace in the 

western part of the Colorado Plateau physiographic 

province. This part of the province is characterized by 

gently dipping sedimentary rocks cropping out in deeply 

eroded plateaus and mesas. The Kolob Terrace trends 

northwest and extends for about 30 mi from Orderville to 

Cedar City, Utah (fig. 3). The terrace gives way to the 

higher Markagunt Plateau to the north; the terrace's 

eastern boundary is the Sevier fault zone and its western 

boundary is the Hurricane fault zone. The study areas 

are underlain by about 13,000 ft of Phanerozoic rock of 

which about 4,000 ft are exposed. Late Cenozoic uplift, 

and renewed activity along the Hurricane fault zone, 

accompanied and followed by deep erosion and volcanism (basalt flows and cinder cones) have produced the 

geologic setting of the present-day Kolob Terrace.

Description of Rock Units

Subsurface Rocks

Rocks in the subsurface of the study areas are of 

Paleozoic and early to middle Mesozoic ages and are 

more than 9,500 ft thick. Of the subsurface rocks, only 

the Springdale Sandstone Member of the Moenave 

Formation is also exposed at the surface. The following 

information pertaining to these rocks is extrapolated 

from reports on the Grand Canyon and Zion Park 

regions (Hintze, 1973) and the Canaan Mountain 

Wilderness Study Area (Van Loenen and others, 1988a),

and from oil and gas drill-hole records. The drill holes 

are at Pintura (10 mi northwest of Virgin, Utah (Gary, 

1963)), about 7 mi north of Virgin (North Virgin 

Imperial #19-1 Federal), and near Mount Carmel 

Junction, Utah (Huston Oil and Minerals #41-11 

Federal). Information on the latter two oil and gas wells 

was obtained from files of the Utah Geological and 

Mineralogical Survey.

Paleozoic rocks include, in ascending order: (1) 

more than 2,500 ft of Cambrian and Devonian strata 

including clastic rocks (shale, mudstone, siltstone, sandstone, and conglomerate), carbonate rocks (limestone 

and dolostone), and minor evaporite (gypsum and anhydrite), (2) the Mississippian Redwall Limestone (about 

800-900 ft thick), (3) the Pennsylvanian Callville Limestone (600-800 ft thick), and (4) the Permian Pakoon 

Limestone (750 ft thick), combined Queantoweap and 

Coconino Sandstones (1,350 ft thick), Toroweap 

Formation (550 ft thick), and Kaibab Limestone (about 

260 ft thick). The latter two units contain evaporitic 

rocks. Of these formations, the Redwall, Pakoon, Queantoweap, Coconino, Toroweap, and Kaibab are considered to be potential oil and gas reservoirs.

Mesozoic rocks include the following strata. The 

Lower and Middle(?) Triassic Moenkopi Formation is 

about 1,800 ft thick and includes the following members, 

in ascending order: the Timpoweap, lower red, Virgin 

Limestone, middle red, Shnabkaib, and upper red. The 

Timpoweap consists of limestone and shale and is a 

potential oil and gas reservoir. The lower, middle, and 

upper red members are essentially reddish-brown 

siltstone and mudstone and contain minor gypsum; 

the Virgin Limestone Member consists mostly of finegrained impermeable gray limestone and interbedded 

pale-reddish-brown shale; and the Shnabkaib Member 

is largely reddish-brown siltstone and mudstone that 

contain beds, lenses, nodules, and stringers of 

noncommercial-grade gypsum. Overlying the Moenkopi, 

the Upper Triassic Chinle Formation is made up of the 

Shinarump Member (about 80-140 ft thick) and the 

overlying Petrified Forest Member (240-280 ft thick). 

The Shinarump is predominantly sandstone and conglomerate and minor shale, and the Petrified Forest 

Member is variegated claystone and shale containing 

volcanically derived clay and fluvial channel-fill sandstones. Both members contain uranium-bearing strata in 

many parts of the Colorado Plateau, although none of 

commercial tenor are known in the vicinity of the study 

areas. The top of the Chinle is estimated to be about 

500-4,000 ft below the surface in the study areas. 

Overlying the Chinle, the Lower Jurassic(?) Moenave 

Formation is about 400 ft thick and consists of three 

members, in ascending order: the Dinosaur Canyon, 

Whitmore Point, and Springdale Sandstone Members. 

They consist of reddish-brown to gray siltstone, mudEl 2 Mineral Resources of Wilderness Study Areas Southwestern Utah
stone, shale, and sandstone of fluvial and lacustrine 

origin. The Springdale Sandstone Member in the Silver 

Reef mining district at Leeds, Utah, was mined 

principally for silver in the late 19th century and for 

uranium in the early 1950's, but similar deposits are not 

known in the Springdale elsewhere.

Surface Rocks

About 4,000 ft of rocks are exposed at the surface 

in and near the study areas; they are Jurassic and 

Cretaceous sedimentary rocks and, locally, Quaternary 

lava flows. In the following sections, the rocks are 

described in ascending order.

Jurassic Rocks

The Lower Jurassic(?) Springdale Sandstone 

Member of the Moenave Formation (Jms) of the Glen 

Canyon Group is present only along the western edge of 

map C (pi. 1). This unit is a resistant cliff-forming paleto light-red crossbedded sandstone that forms the surface 

for much of Smith Mesa. The Springdale is about 100 ft 

thick.

The Lower Jurassic(?) Kayenta Formation (Jk) is a 

reddish-brown siltstone, sandstone, and shale of fluvial 

and lacustrine origin, with some clay of probable volcanic 

derivation. This ledge-forming rock unit forms the lower 

part of Red Butte when viewed from the west on Smith 

Mesa. It is 700-800 ft thick in exposures in and adjacent 

to the Red Butte study area (map C, pi. 1); it is not 

exposed in the other seven study areas. No mineral or 

energy resources are known to occur in the Kayenta.

The Lower Jurassic(?) Navajo Sandstone (Jn) 

overlies the Kayenta and is exposed in all eight study 

areas (pi. 1). Although no complete sections of the 

Navajo are exposed in the study areas, it is as much as 

2,200 ft thick in Zion National Park and 1,800-2,000 ft 

thick to the east in the Kanab 15-minute quadrangle 

(Sargent and Philpott, 1987). It forms spectacular, nearly 

vertical canyon walls in seven of the study areas, and it 

forms the upper part of the prominent butte in the Red 

Butte study area. The Navajo is characterized in all the 

study areas by pervasive sets of northwest- to northeasttrending joints. Weathering along these joints produced 

the jagged skyline on the summit of Red Butte. The 

Navajo is a homogeneous, loosely cemented, fine- to 

medium-grained, well-sorted sandstone exhibiting outstanding examples of medium- to large-scale eolian 

crossbedding. It was deposited in an extensive desert 

"sand sea" that encroached southward from highlands 

north of the study areas about 180 million years ago. The 

Navajo is generally moderate reddish orange in its lower 

part and very light gray to nearly white in its upper part. 

The color differences are due mainly to the effects of

ground water on the cementing agents of lime, iron 

oxides, and clays. No mineral or energy resources are 

known in the Navajo although it is an excellent groundwater aquifer. Its great thickness, weathering properties, 

varied colors, crossbedding features, and fracture 

patterns combine to provide the most scenic characteristics of any rock formation exposed in the region.

The Moenave, Kayenta, and Navajo have for many 

years been considered to be either Triassic or Triassic 

and Jurassic in age. Peterson and Pipiringos (1979), 

however, considered them to be provisionally Early 

Jurassic on the basis of palynomorphs in the Moenave. 

Their usage is used in this report.

The Middle Jurassic Temple Cap Sandstone (Jtc) 

consists of two members, the Sinawava and White 

Throne (Peterson and Pipiringos, 1979). The members 

were not mapped separately in this report. The Sinawava 

is a slope-forming unit of interbedded reddish-brown 

sandstone, siltstone, and mudstone. It is overlain by the 

White Throne, which is a cliff-forming, light-gray to tan, 

fine-grained, crossbedded sandstone of eolian origin. The 

Temple Cap thins from southeast to northwest across the 

Kolob Terrace, ranging in thickness from about 200 ft 

near the Deep Creek study area to only a few feet in the 

LaVerkin Creek Canyon study area (pi. 1). It appears to 

be absent in the Taylor Creek study area. The Temple 

Cap is not known to contain mineral or energy resources.

The Middle Jurassic Carmel Formation averages 

about 700 ft thick and consists of four separately mapped 

members, in ascending order: the limestone, banded, and 

gypsiferous members, and the Winsor Member. The 

limestone member is present in all of the study areas 

except Red Butte. The banded and gypsiferous members 

and the Winsor Member are present in the Orderville 

Canyon, North Fork Virgin River, and Deep Creek study 

areas; the banded member is also present in a small part 

of the LaVerkin Creek Canyon study area (pi. 1). 

Depositional environments of these strata ranged from 

shallow marine, perhaps in restricted embayments or 

lagoons, to marginal marine floodplains, to shallow 

evaporite-precipitating coastal plain environments. The 

only known exploited resources in the Carmel are 

limestone for road metal and alabaster (gypsum) for 

sculpture or ornamental objects.

The limestone member of the Carmel Formation 

(Jcl) ranges from 300 to 400 ft thick and consists of two 

informal units that are roughly equal in thickness. They 

are (1) a lower ledge-forming unit of thin- to mediumbedded, largely lithographic, tan-weathering limestone 

that grades upwards into a slope-forming unit of shaly 

limestone and interbedded pale-green and reddishbrown shale, and (2) an upper cliff-forming unit of 

relatively pure limestone much like that in the lower unit.

Eight Wilderness Study Areas Bordering Zion National Park E13
Marine fossils (pelecypods, gastropods, and crinoid 

remains) are locally common but generally sparse; minor 

oolitic limestone is most common in the upper unit.

The banded member (Jcb) is 120-160 ft thick and 

is generally poorly exposed and forms gentle to moderate 

slopes. Alternating beds of light-gray and reddish-brown, 

thin-bedded, friable sandstone and siltstone form a 

banded pattern where the member is well exposed.

The gypsiferous member (Jcg) is about 40 ft or 

less to 60 ft thick and consists of a lower ledge-forming 

unit of white to very light gray to pink gypsum and an 

upper slope-forming unit of gray and pale-green gypsiferous limestone, sandstone, and shale. The lower and 

upper contacts are not well defined, although a thin 

fossiliferous limestone bed at least locally marks the top 

of the member (Cashion, 1967b).

The Winsor Member (Jew) is about 180-200 ft 

thick and is generally very poorly exposed; it weathers to 

smooth, gentle slopes. It is largely a very fine grained 

friable moderate-red sandstone with thin interbeds of 

reddish-brown mudstone.

Cretaceous Rocks

Cretaceous rocks unconformably overlie the 

Carmel Formation. The unconformity represents a 60- 

million-year period of erosion and nondeposition that 

occurred throughout southwest Utah during the Sevier 

orogeny.

Upper Cretaceous rocks in and near the study 

areas are as much as 3,500 ft thick and consist of the 

Dakota Formation, Tropic Shale, and Straight Cliffs 

Sandstone. In this report, the Dakota and Tropic were 

mapped together as map unit Ktd.

The Dakota Formation in this general region is 

commonly made up of sandstone and conglomerate 

ranging from 0 to as much as 80 ft thick, which are locally 

replaced by a thin conglomerate having a shale matrix. 

Complete sections of the Dakota Formation and the 

Tropic Shale east of the study areas are about 900-1,400 

ft thick (Cashion, 1967a). The Tropic there consists of 

two members. The lower member is about 200-600 ft 

thick and consists of carbonaceous shale, sandstone, and 

coal. This member is delimited by upper and lower coal 

zones. The upper member is about 500-1,200 ft thick and 

consists of mostly gray carbonaceous shale, minor 

shoreline-deposited sandstone, and thin coal beds. The 

Dakota and Tropic (Ktd) are present in a small area 

along the eastern part of the Orderville Canyon study 

area (map D, pi. 1), in the northern part of the North 

Fork Virgin River study area (map B, pi. 1), and in the 

northeastern part of the Deep Creek study area (map B, 

pi. 1). Anomalous amounts of uranium occur locally in 

conglomerate beds in the Dakota, and coal has been 

mined commercially in the region from the lower 

member of the Tropic.

The Straight Cliffs Sandstone (Ksc), about 

120-600 ft thick, of which only the lower part is exposed 

(map B, pi. 1), intertongues with the Tropic Shale 

according to Cashion (1967a). The Straight Cliffs is a 

gray, planar-bedded sandstone, deposited mostly under 

marine shoreline conditions, interbedded with gray 

marine shale.

Quaternary Deposits

During Quaternary time, parts of the Kolob 

Terrace were covered with basalt flows (Qb) and cinder 

cones (Qc) produced during several volcanic events. The 

flows accumulated to several hundreds of feet in 

thickness and covered a topographic surface not unlike 

the present-day surface. The flows are fresh-appearing, 

homogeneous, black to gray, massive to vesicular olivine 

basalt. Cinder cones are common on the flows, and they 

may represent the final stages of volcanism for separate 

flow events. There are many cones, some more than 400 

ft high, scattered as landmarks across the Kolob Terrace. 

Basalt flows and a 300-ft-high cinder cone occur to the 

southeast of the Red Butte study area. There are no 

volcanic rocks exposed in the Red Butte study area, but 

they may exist beneath eolian sand and silt cover in the 

southern part. Fjrtensive areas of Quaternary volcanic 

rocks are exposed 1 mi to the east of Red Butte in Zion 

National Park. At least three separate flows cover parts 

of the Deep Creek study area, with total accumulations 

of 140-400 ft. Basalt flows came from both the northwest 

and northeast and flowed into the upper parts of Deep 

Creek. The creek was probably dammed by the flows, but 

subsequent erosion has cleared the canyon. A cinder 

cone is situated on the flows about 1A mi north of the 

Deep Creek study area. Cinders from the more 

accessible cones in the region are used locally for road 

metal.

Basalt talus (Qbt), shown in areas of volcanic 

terrane near the Red Butte study area (map C, pi. 1) and 

in the Deep Creek study area (map B, pi. 1), represents 

an accumulation of large blocks of lava at the base of 

steep slopes. In part, the talus may represent fragmented 

flow edges produced during flow activity.

Eolian sand and silt (Qes) includes deposits of 

relatively small, currently active dunes and sheets and 

some older stabilized dunes. Sand and silt are light gray 

to yellowish gray, buff, and reddish orange, fine to 

medium grained, and composed mostly of quartz and 

very minor heavy minerals. The Navajo Sandstone is the 

chief source rock for this unit. These deposits occur 

where the Navajo is exposed on an upland surface in the 

Red Butte study area.

Landslide deposits (Qlsf), as mapped, include 

debris flow, slide, slump, and creep deposits of both 

bedrock and surficial materials. These deposits occur in

E14 Mineral Resources of Wilderness Study Areas Southwestern Utah
the Orderville Canyon, North Fork Virgin River, and 

Deep Creek study areas and consist mostly of disrupted 

shale and sandstone of the Tropic Shale. The Tropic, due 

to a high content of expanding clays, is prone to sliding. 

Initial movements of the slides may have been in early 

Quaternary time, but present small scarps indicate recent 

movement. Some smaller slides (not mapped) have 

occurred on the Kayenta Formation in the Red Butte 

study area.

Alluvium and colluvium (Qac) consist of (1) 

unconsolidated clay, sand, gravel, and silt as channel, 

floodplain, and lacustrine deposits, (2) local, alluvial-fan 

deposits and talus from rockfalls, and (3) relatively small 

landslide deposits and slump material (see pi. 1).

Structure

Although the Kolob Terrace lies between two 

major fault zones (Hurricane and Sevier), the terrace 

itself is relatively structureless. The sedimentary rocks 

dip slightly more than 1° NE., with mildly steeper dips 

occurring locally. Two major northerly trending faults 

(Beartrap and Wildcat Canyon) cut the Kolob Terrace, 

but they lie outside of the study areas. The Beartrap fault 

is about ¥1 mi to the northwest of the Beartrap Canyon 

study area. This fault is a northeast-trending normal fault 

that has as much as 800 ft of displacement. The fault can 

be traced for more than 5 mi from within Zion National 

Park to the northeast where it is concealed beneath 

landslide deposits. The northern extent of the Wildcat 

Canyon fault is about 2 mi west of the Goose Creek 

Canyon study area in the park. Faults having minor 

displacement occur in the Deep Creek, LaVerkin Creek 

Canyon, and Taylor Creek Canyon study areas. Numerous northwest- to northeast-trending, nearly vertical 

fractures or joints are well expressed in the Navajo 

Sandstone. Displacement along these fractures is negligible, and alteration or mineral deposits are not 

associated with them.

Geophysics

Gravity Data

The Bouguer gravity map (fig. 4) was compiled 

using data from 111 stations established by the USGS in 

1986 and 1987 for BLM wilderness projects and from 95 

stations established previously, the majority by the 

University of Utah (principal facts are available from the 

National Center for Geophysical and Solar-Terrestrial 

Data, Boulder, CO 80301). All gravity observations were 

reduced at a density of 2.67 g/cm3 (grams per cubic

centimeters) through standard USGS procedures (see, 

for example, Cordell and others, 1982).

The Bouguer gravity map (fig. 4) is dominated by a 

northeast-trending negative gradient whose average 

change in intensity is nearly 1 mGal (milligal) per 

kilometer. Three factors contribute to this gradient. First, 

the standard reduction density is significantly greater 

than the mean density of rocks above the topographic 

datum, which are predominantly clastic; therefore, the 

gradient must in part reflect the drastic increase in 

elevation from the Virgin River in the southwest to the 

Markagunt Plateau in the northeast. Use of a lower 

reduction density, for example 2.4 g/cm3 , ameliorates the 

regional gradient and virtually eliminates the sharp 

reentrant associated with Zion Canyon (stations on the 

canyon floor have relatively positive Bouguer values on 

fig. 4; the surrounding topography consists chiefly of 

Navajo Sandstone). Second, isostatic compensation of 

the topography may in part be affected by crustal 

thickening, which would produce more-negative 

Bouguer values in areas of higher altitude. Airy-type 

isostatic compensation could not, however, account for 

the steep gradient represented by the narrow belt of 

closely spaced contours running diagonally across the 

center of the map area from southeast to northwest. Also 

the regional gradient can still be found on an isostatic 

anomaly map of the Western United States based on an 

Airy model, although the gradient is reduced in 

amplitude. Third, it has been established from structural 

contour maps on sedimentary horizons that the elevation 

of the surface of the Precambrian crystalline basement 

falls off to the northeast. This deepening of the highdensity basement is probably the chief factor contributing 

to the regional gravity gradient. The data suggest the 

existence of a Precambrian structural high centered to 

the southwest of the map area; a north-plunging anticlinal extension of this high is indicated by the Bouguer 

gravity high in the northwest corner of the map area, 

bounded on the west by a gradient associated with the 

Hurricane fault. The steepest part of the regional 

gradient may represent a "step" or local steepening of the 

basement surface not reflected by disturbance of the 

surface rocks. No apparent relation exists between this 

gravity structure and the distribution of volcanic centers 

or other features mapped in the region.

Aer©magnetic Data

The residual total-intensity aeromagnetic map 

(fig. 5) was prepared from data acquired for the NURE 

program. NURE traverses in the region were flown 

east-west at a nominal 400 ft above terrain and a 3-mi 

flight-line spacing. The Earth's main magnetic field has 

been removed from the data along with diurnal and other 

extraneous effects as part of the standard reduction 

procedure.

Eight Wilderness Study Areas Bordering Zion National Park E15
112°45'

5 

____I________

EXPLANATION

Gravity cdntour Contour interval 2 milligals.

Hachures indicate closed low 

Gravity station

From this study 

Previously established

Fault or fracture Dashed where approximately located or concealed (after 

Hintze, 1973)

10 MILES

Quaternary basalt (after Hintze, 1973) 

Volcanic vent

"i Approximate boundary of wilderness 

study area For names, see figure 2

 Boundary of Zion National Park

Figure 4. Complete Bouguer gravity anomaly contours of the eight wilderness study areas and vicinity, Utah.

E16 Mineral Resources of Wilderness Study Areas Southwestern Utah
11 3°00' 112°45'

10 MILES 

I

EXPLANATION

 100 Aeromagnetic contour Contour interval 20 

nanoteslas. Hachures indicate close low

Fault or fracture Dashed where approximately located or concealed (after 

Hintze, 1973)

Quaternary basalt (after Hintze, 1973)

# Volcanic vent

^ Approximate boundary of wilderness study

area For names, see figure 2

 - Boundary of Zion National Park

Figure 5. Residual total-intensity aeromagnetic contours of the eight wilderness study areas and vicinity, Utah.

Eight Wilderness Study Areas Bordering Zion National Park E17
The aeromagnetic map (fig. 5) upon first appraisal 

shows little correlation with the gravity map. However, 

the axis of the broad magnetic high that occupies much of 

the region is oriented northeast-southwest, roughly in the 

mean direction of the regional gravity gradient, and both 

maps show a fabric of northeast-trending minor highs. 

The crest of the broad high is a superimposed subcircular 

anomaly of maximum intensity about 240 nT (nanoteslas), located near lat 37°15' N., long 113°00' W. A 

rough depth estimate for the anomaly source in this 

vicinity is 2-2.5 mi, or approximately the total thickness 

of the Phanerozoic section as obtained from a composite 

of stratigraphic measurements and deep-drilling data. 

Thus the subcircular anomaly is attributable to a source 

within the basement complex, possibly an intrusive body 

of Precambrian age such as the granitic pluton exposed 

some 50 mi to the west in the Beaver Dam Mountains, 

which produces an anomaly of similar shape and 

amplitude. The broad high as a whole most likely represents the combined effects of numerous sources in the 

basement. Aeromagnetic basement depths seem to 

increase to the northwest, southeast, and less drastically, 

to the northeast only in a very general way do they 

follow the configuration of the basement surface inferred 

from gravity data. This lack of coincidence may be partly 

explained by the relatively greater role of intrabasement 

magnetization contrasts as compared with density 

contrasts. For further explanation, a more detailed study 

of the two data sets is required.

The only additional sources of aeromagnetic field 

disturbances are basalt flows and associated vent rocks of 

Quaternary age. These rocks occur both on the modern 

plateau surfaces and at lower altitudes in the intervening 

valleys. Because of the wide flight-line spacing and large 

irregularities in terrain clearance on most NURE surveys 

over rugged topography, the configuration of "shallow" 

sources of limited area! and depth extent inferred from 

NURE data is generally not reliable. Each discrete 

short-wavelength anomaly high seen on figure 5 results 

from overflight of a strongly magnetized basaltic source 

on a single traverse. Sources that occur between traverses 

or that are thin relative to the terrain clearance were not 

detected. Likewise the data reveal no concealed hypabyssal basaltic intrusions.

Aeroradiometric Data

East-west flight lines of the NURE aeroradiometric survey (same survey as for aeromagnetic data) 

traverse the study areas. Aerial gamma-ray spectroscopy 

is a technique that provides estimates of the near-surface 

concentrations of percent potassium (K), parts per 

million equivalent uranium (eU), and parts per million 

equivalent thorium (eTh). Because the uranium and 

thorium measurements utilize radioactive daughter

nuclei that are chemically distinct from the parent nuclei, 

the uranium and thorium data are described as equivalent concentrations. These data (K, eU, eTh) provide a 

partial geochemical representation of the near-surface 

materials. For a typical aerial survey, each measurement 

reflects average concentrations for a surface area on the 

order of 15 acres to an average depth of about 1 ft (J.S. 

Duval, USGS, written commun., 1987). Examination of 

the data by Duval indicates that the eight wilderness 

study areas have overall low radioactivity with K ranging 

from 0.8 to 2.0 percent, eU from 0.1 to 3.0 ppm, and eTh 

from 1 to 8 ppm. No significant anomalies were observed 

within or adjacent to any of the study areas. An eU 

anomaly was, however, detected about Vi mi east of the 

Orderville Canyon study area over an abandoned 

uranium mine in the Dakota Formation. One of the 

east-west NURE traverses passed over the Dakota 

Formation about 1,900 ft northeast of the mine adits at a 

ground clearance of 500-600 ft. Concentrations of eU 

detected there are about twice background.

Geochemistry

Methods

A reconnaissance geochemical survey was conducted in only the largest of the eight study areas: 

Orderville Canyon, North Fork Virgin River, Deep 

Creek, and LaVerkin Creek Canyon. Samples taken from 

these four study areas, which are all on tributaries of the 

Virgin River, would seemingly characterize the geochemistry of the entire area including all eight study areas. 

Stream sediments and nonmagnetic heavy-mineral concentrates separated from the stream sediments were the 

sample media used for this survey. Stream sediments are 

a composite of the rock and soil upstream in the drainage 

basin. Analysis of the stream sediments and their heavymineral constituents may identify basins that contain 

anomalous concentrations of elements that might be 

related to unknown mineral occurrences. Analytical data 

and a description of the sampling and analytical methods 

are in Bullock and others (in press).

Twenty four stream-sediment samples and concentrates were collected from the four study areas. The 

stream sediments were screened and dried prior to 

analysis. The stream sediments and the heavy-mineral 

concentrates were analyzed for 31 elements by emission 

spectrographic methods. In addition, the stream sediments were analyzed for arsenic, antimony, bismuth, 

cadmium, zinc, gold, and uranium.

Nonmagnetic heavy-mineral concentrates were 

separated from the stream concentrates in the laboratory 

using heavy liquids and an electromagnet. Most orerelated sulfide and oxide minerals are relatively heavy

E18 Mineral Resources of Wilderness Study Areas Southwestern Utah
and nonmagnetic. The removal of most of the lightweight rock-forming silicates, clays, organic material, and 

magnetic minerals permits the determination of some 

elements present in the concentrates that are not easily 

detectable in stream sediments.

Radioactivity was measured at selected outcrops of 

the Dakota and at all sampling sites.

Results

Threshold values (minimum concentrations considered anomalous for particular elements) in the bulk 

stream sediments and nonmagnetic heavy-mineral 

concentrates were determined by inspection of the 

analytical data. None of the stream sediments or 

concentrates collected from the four study areas had 

anomalous amounts of any of the analyzed elements, nor 

were any sampling sites or outcrops found to be 

radioactive.

Mineral and Energy Resources

There has been no mining within any of the eight 

study areas. Terrain underlain by Cretaceous rocks in the 

Orderville Canyon, North Fork Virgin River, and Deep 

Creek Canyon study areas was probably explored in the 

past for uranium deposits, such as those present nearby 

in Orderville Canyon, and for sources of coal. These 

three study areas are partly in the Kolob coal field. Other 

than industrial minerals (limestone and gypsum), the 

Jurassic rocks exposed in the eight study areas contain no 

known mineral or energy resources nor are they known 

to contain any in the region. Although southwest Utah is 

not known for oil and gas production, the study areas are 

relatively close to two abandoned oil fields. The following 

sections discuss the attributes of nearby localities where 

specific commodities have been produced and compare 

those attributes to the ones present within the study 

areas. The mineral resource potential is summarized in 

table 1.

Oil and Gas

Utah's oil and gas production comes primarily 

from three areas: the thrust belt of north-central Utah, 

the Paradox Basin of southeastern Utah, and the Uinta 

Basin of northeastern Utah. A few small fields that have 

produced or are currently producing oil and gas exist 

outside these three areas. The only producing field in 

southwestern Utah is the Upper Valley field located near 

Escalante, Utah, about 65 mi northeast of the study 

areas. The abandoned Anderson Junction and Virgin 

fields are about 8 mi southwest and south, respectively, of 

Red Butte.

Due to the proximity of the Virgin field and its 

similar geologic setting, the attributes of this field are 

used in the evaluation of oil and gas potential beneath the 

study areas. Oily tar that occurs in seeps in the vicinity of 

the Virgin field and several other localities nearby 

prompted exploration for oil and gas. The first well was 

drilled in the Virgin field in 1907. Since 1907, more than 

150 wells have been drilled in and near the Virgin field, 

the latest being in 1986. Some of the wells produced as 

much as 30 BOPD (barrels of oil per day), but most wells 

yielded only 1-4 BOPD from shallow wells ranging from 

500 to 800 ft deep. Total production from the Virgin field 

has been slightly more than 200,000 barrels of asphaltparaffin base oil; most wells produced little or no gas.

The reservoir rocks in the Virgin field are limematrix conglomerates provisionally interpreted to be in 

the upper part of the Kaibab Limestone, and sandy 

limestones of the Timpoweap Member of the Moenkopi 

Formation. Oil in the Virgin field apparently accumulated in a structural low on the nose of a broad, very 

gently plunging anticline. Differences in the physical 

properties of the oil from well to well may indicate 

separate stratigraphic traps within the structural low 

(Bahr, 1963). A structural high adjacent to and northeast 

of the Virgin field and 3 mi south of the Red Butte 

Wilderness Study Area was tested by drilling in 1986. 

This well bottomed in the Pennsylvanian Callville 

Limestone. Traces of dead oil were seen in some 

samples, and massive amounts of fresh water were 

encountered in limestones of the Timpoweap, Kaibab, 

and Toroweap. The well was considered dry and was 

abandoned (P. Carter, BLM, Cedar City, Utah, written 

commun., 1987).

Other structural highs in the region have been 

tested for oil, but none successfully. Four wells were 

drilled, one as recently as 1985, on a small anticline 

located south of the Virgin field. Commercial quantities 

of oil were not found in any of the wells.

The Colorado Plateau has had a favorable thermal 

history for the generation of oil and gas (Ryder, 1983), 

and some oil in this area may have been generated locally 

in Paleozoic and lower Mesozoic rock; however, there 

are no known source rocks rich in hydrocarbons. Such 

source rocks, for example, are the organic-rich shales of 

Pennsylvanian and Permian age from which oil is 

generated in the Paradox and Uinta Basins. The source 

of oil in this part of the Colorado Plateau in southwest 

Utah may be the abundant organic-rich Paleozoic rocks 

of the adjoining Basin and Range physiographic province 

in eastern Nevada and western Utah (Giardina, 1979). 

The most significant of these is the Mississippian Chainman Shale, which provided oil to fields in east-central 

Nevada (Poole and Claypool, 1984). This source rock 

may have supplied hydrocarbons that subsequently 

underwent long-range migration across a structural

Eight Wilderness Study Areas Bordering Zion National Park E19
hingeline updip into southwestern Utah and northwestern Arizona. The hingeline is the boundary between 

the tectonically stable Colorado Plateau and the Basin 

and Range province.

Potential

The eight wilderness study areas have a moderate 

energy resource potential for oil and gas, with certainty 

level C, based on the structural and stratigraphic settings, 

proximity to the Virgin field, and results of exploration in 

the region. The surface geology is well known in the study 

areas, but there are no subsurface data. Exploration by 

drilling would be required to identify petroleum 

resources, and none has been done within the study 

areas. This assessment concurs with the rating given the 

study areas by Molenaar and Sandberg (1983).

Structural traps such as the mild upwarping of the 

sedimentary rocks in the Virgin field may be present 

beneath the study areas, although there are no known 

surface manifestations of significant structures. These 

subtle features, if present, would be difficult to locate in 

the study areas. The Virgin field structure trends northnortheast, and if this feature continued it could possibly 

affect strata beneath the Red Butte study area. Current 

oil and gas leases of part of the Red Butte and Beartrap 

Canyon study areas illustrate interest in this area. The 

possible reservoir rocks within the study area boundaries 

are buried beneath 2,500-6,000 ft of Triassic and Lower 

Jurassic rocks.

Stratigraphic traps resulting from facies changes in 

favorable rocks may form reservoirs for oil and gas 

beneath the study areas. Regionally, the study areas are 

updip from and on the eastern edge of the Paleozoic 

geosyncline where accumulations of sediments thin 

eastward from more than 20,000 ft in the deeper parts of 

the geosyncline to about 7,000 ft in this area. An 

environment such as this, wherein formations thin or 

wedge out on a continental shelf, is conducive to forming 

facies-change stratigraphic traps. Exploration in the 

region indicates that the most favorable reservoirs for oil 

and gas are in the Timpoweap Member of the Moenkopi 

Formation, Kaibab Limestone, Toroweap Formation, 

Queantoweap and Coconino Sandstones, and Pakoon, 

Callville, and Redwall Limestones. These formations are 

probably present at depth beneath the study areas.

The potential for oil and gas in the region is not 

high because the available reservoir rocks have been and 

still are susceptible to flushing by fresh water that was 

first introduced into the rocks in late Tertiary time after 

the region was uplifted and deeply dissected by erosion 

(Ryder, 1983). The presence of fresh water is not well 

documented in drilling records; however, it may be 

pervasive. The well drilled south of Red Butte in 1986, 

mentioned earlier in this report, contained massive

amounts of water in the Timpoweap, Kaibab, and Toroweap, all potential reservoir rocks (P. Carter, BLM, 

Cedar City, Utah, written commun., 1987). Drilling 

records from a well drilled in the Anderson Junction field 

showed fresh water flowing in the Callville Limestone 

and Redwall Limestone (Giardina, 1979).

Metals

The eight wilderness study areas have a low 

mineral resource potential for all metals, including 

silver and uranium, with certainty level D. The bulk of 

the rock units exposed in the study areas (Navajo and 

Temple Cap Sandstones, and Carmel Formation) are 

not known to contain ore deposits anywhere in the 

region, and it is unlikely that any occur in the rock units 

within the study areas. The Dakota, however, contains 

anomalous amounts of uranium nearby.

Silver

The Springdale Sandstone Member of the Moenave Formation hosts silver-rich ore and associated 

uranium at the Silver Reef district (fig. 3), and is 

probably present in the subsurface beneath the eight 

study areas. The Moenave crops out west of the Red 

Butte Wilderness Study Area (pi. 1, map C) and is 

probably present beneath the other seven study areas at 

depths exceeding 2,000 ft. Mineral deposits are not 

known to occur in this formation outside the Silver Reef 

district; it is therefore unlikely that similar mineral 

deposits occur in the study areas.

Uranium

Southwestern Utah has not been a major producer 

of uranium; however, southeastern Utah contains 

significant uranium deposits in the Morrison and Chinle 

Formations. The Morrison is not present in southwestern 

Utah, but the Chinle lies beneath the study areas at 

depths of 500-4,000 ft. Uranium was reportedly mined 

from the Chinle south of the study areas in Arizona 

(Kreidler, 1986). Similar uranium deposits in the Chinle 

are not known in or near the study areas; however, trace 

amounts of uranium do occur in a prospect pit in the 

Chinle south of Red Butte (fig. 3).

Abandoned uranium mines are located in the 

Silver Reef district (as previously discussed) and east of 

the Orderville Canyon study area, where uranium was 

mined from the Dakota Formation.

Uranium occurs east of the Orderville Canyon 

study area in a sandstone-hosted uranium deposit in the 

Dakota Formation (deposit discussed in previous section

E20 Mineral Resources of Wilderness Study Areas Southwestern Utah
by USBM). Several claims were staked on the Dakota 

exposures after prospecting began in 1949 and some ore 

was shipped but its uranium content was submarginal 

(Beroni and others, 1953).

Sandstone-hosted uranium deposits form when 

uranium and other metals, which are carried in solution 

in ground water, precipitate to form stable minerals 

under reducing conditions. The reducing conditions are 

caused by the carbonaceous material or iron sulfides 

present in highly permeable sandstones through which 

the metal-rich solutions flow. These uranium deposits 

characteristically contain trace amounts of vanadium, 

molybdenum, copper, and selenium, and have anomalous radioactivity. Samples from the Orderville Canyon 

uranium prospects were reported to contain all of these 

elements except selenium, and the Dakota outcrops 

there were radioactive to varying degrees (Beroni and 

others, 1953); they also contained abundant carbonaceous material. These characteristic properties were not 

found in outcrops of the Dakota in the study areas. A 

very small outcrop of Dakota is well exposed in the 

southeastern part of the Orderville Canyon study area, 

but no uranium was found associated with it. The Dakota 

may underlie the northern part of the North Fork Virgin 

River study area and the northeastern part of the Deep 

Creek study area, but because exposures are mostly 

covered, it is not clear how much Dakota is present. No 

anomalous radioactivity was found in the vicinity of any 

Dakota outcrops in these three study areas, nor did the 

NURE aeroradiometric survey detect any anomalous 

radioactivity other than that near the uranium mine in 

Orderville Gulch. The Dakota is not present in the Goose 

Creek Canyon, Beartrap Canyon, LaVerkin Creek 

Canyon, Taylor Creek Canyon, or Red Butte Wilderness 

Study Areas, nor is any rock unit exposed in these study 

areas known to contain uranium. The geochemical 

survey of the Orderville Canyon, North Fork Virgin 

River, Deep Creek, and LaVerkin Creek Canyon study 

areas did not reveal any anomalies suggesting the 

presence of uranium mineral deposits.

Geothermal Sources

The study areas have a low energy resource 

potential for geothermal sources, with certainty level D. 

The study areas are located along the western edge of the 

Colorado Plateau, a tectonically stable province characterized by low heat flow that provides only a meagre basis 

for geothermal sources. By comparison, the adjoining 

Basin and Range province is tectonically active, and has a 

high heat flow, and thus a favorable basis for geothermal 

sources. The study areas are about 15 mi northeast of 

thermal springs that discharge warm water (106 °F) into 

the Virgin River near Hurricane, Utah. These springs are 

along, and probably controlled by, fractures in the

Hurricane fault zone. This major structure is in the 

transition zone between the Colorado Plateau and the 

Basin and Range provinces. Warm springs do not occur 

in the study areas.

Coal

Coal has been mined from several localities in the 

Kolob coal field northeast of Zion National Park in parts 

of Washington, Kane, and Iron Counties, Utah. The 

Kolob coal field extends for more than 30 mi from 

Orderville to Cedar City, and it roughly outlines the 

Kolob Terrace (fig. 3). Coal was discovered in 1850 near 

Cedar City, and its first use was to make coke for blast 

furnaces in local iron smelters. Later uses were to fuel 

mines and small power plants in the region, but 

competition from suppliers of higher grade coal, the 

shutdown of iron mines, and the use of natural gas 

caused all of the coal mines in the Kolob field to close by 

1969 (Doelling and Graham, 1972).

Coal in the Kolob coal field occurs primarily in the 

Tropic Shale and in minor amounts in the overlying 

Straight Cliffs Sandstone and Wahweap Formation. All 

of these rock units are of Late Cretaceous age. Coal beds 

originated here from peat that collected in marshes and 

swamps along prograding and retrograding shorelines of 

the Cretaceous sea. The Straight Cliffs and Wahweap are 

not present in the study areas.

Coal occurs in the upper and lower zones of the 

coal-bearing member of the Tropic Shale. The upper 

zone contains most of the important coal beds, and 95 

percent of the coal mined from the Kolob field was taken 

from this zone. The upper coal zone is thought to be 

continuous from Orderville to Cedar City. It rises in 

stratigraphic position from about 120 ft above the 

Carmel Formation at Orderville to nearly 1,000 ft above 

the Carmel near Cedar City (Doelling and Graham, 

1972). Coal beds in the upper zone range from 2 to 9 ft 

thick, and they were exploited in several mines near 

Cedar City and in the southeastern part of the field near 

Orderville. The King Cannel mine (now abandoned) (fig. 

3) is the closest coal mine to the study areas. It is located 

on the south bank of the North Fork of the Virgin River 

about 6 mi northeast of the Orderville Canyon study area 

and 5 mi east of the North Fork Virgin River study area. 

Coal was mined there from the upper coal zone.

The lower coal zone ranges from 35 to 100 ft 

stratigraphically above the Carmel Formation in the area 

between Deep Creek and Orderville. Coal in the lower 

zone is erratic, usually occurring in several thin beds 

within a 2- to 5-ft interval. No significant coal beds are 

known from this zone.

Coal from the Kolob field is generally of poor 

quality. The average ash and sulfur content of coal from 

the Cedar City area are 10.8 percent and 5.7 percent,

Eight Wilderness Study Areas Bordering Zion National Park E21
respectively, and in the Orderville area ash averages 11.5 

percent and sulfur 2.2 percent (Doelling and Graham, 

1972).

Potential

The energy resource potential for coal is low, with 

certainty level D, in three of the eight wilderness study 

areas: Orderville Canyon, North Fork Virgin River, and 

Deep Creek. Although part of the Tropic underlies parts 

of these three study areas, the upper coal zone lies 

outside the study areas. The upper coal zone is estimated 

to be about 600 ft (data from measured sections nearby; 

Doelling and Graham, 1972) above the Carmel Formation in the vicinity of the three study areas. A maximum 

of only 300 ft of the Tropic is present within the study 

area boundaries.

The lower coal zone historically has not been a 

viable coal resource in the Kolob field because of its low 

quality and the relatively thin and lenticular nature of the 

beds. The lower zone is not present in the Orderville 

Canyon study area, but the stratigraphic interval is 

present in the North Fork Virgin River and Deep Creek 

study areas although it is very poorly exposed. Coal from 

the lower zone has little potential outside the study areas, 

and if the coal zone maintains similar qualities in the 

study areas, it too would seemingly have little economic 

value.

There are no rocks of Cretaceous age present in 

the other five study areas, nor are there any other rock 

units exposed or in the subsurface that are known to 

contain commercial coal deposits. These five study areas 

have no potential for coal resources, with certainty level 

D, because of unfavorable geologic conditions.

Gypsum

The gypsiferous member of the Carmel Formation 

occurs in the areas shown as having identified resources 

of gypsum in the Orderville Canyon, North Fork Virgin 

River, and Deep Creek study areas (pi. 1, maps B and D). 

The member undoubtedly occurs at depth behind the 

gypsiferous outcrops in these study areas. The gypsiferous member of the Carmel Formation is not present in 

any other parts of these three study areas. Therefore 

these three study areas have no mineral resource 

potential for additional gypsum, with certainty level D. 

The gypsiferous member of the Carmel is not present in 

any of the other five study areas, nor do any other rock 

units exposed contain gypsum. Therefore the other five 

study areas have no mineral resource potential for 

gypsum resources, with certainty level D.

REFERENCES CITED

Appleyard, F.C., 1983, Gypsum and anhydrite, in Lefond, S.J., 

ed., Industrial minerals and rocks, 5th edition: New York, 

Society of Mining Engineers of the American Institute of 

Mining, Metallurgical, and Petroleum Engineers, Inc., 

v. 2, p. 775-792.

Bahr, C.W., 1963, Virgin oil field, Washington County, Utah, in 

Heylman, E.B., ed., Guidebook to the geology of 

southwestern Utah: Intermountain Association of 

Petroleum Geologists, 12th Annual Field Conference, 

1963, p. 169-171.

Bates, R.L., 1969, Geology of the industrial rocks and minerals: 

New York, Dover Publications, Inc., 459 p.

Beroni, E.P., McKeown, F.A., Stugard, Frederick, Jr., and Gott, 

G.B., 1953, Uranium deposits of the Bulloch group of 

claims, Kane County, Utah: U.S. Geological Survey 

Circular 239, 9 p.

Bullock, J.H., Jr., Barton, H.N., Fey, D.L., and Kennedy, K.R., 

in press, Analytical results and sample locality maps of 

stream-sediment and heavy-mineral-concentrate samples 

from the Deep Creek, La Verkin Creek, North Fork 

Virgin River, Orderville Canyon, and Parunuweap 

Canyon Wilderness Study Areas, Kane and Washington 

Counties, Utah: U.S. Geological Survey Open-File 

Report 88-581.

Gary, R.S., 1963, Pintura anticline, Washington County, Utah, 

in Heylman, E.B., ed., Guidebook to the geology of 

southwestern Utah: Intermountain Association of 

Petroleum Geologists, 12th Annual Field Conference, 

1963, p. 172-179.

Cashion, W.B., 1961, Geology and fuels resources of the 

Orderville-Glendale area, Kane County, Utah: U.S. 

Geological Survey Coal Investigations Map C-49, scale 

1:62,500.

____ 1967a, Geologic map of the south flank of the Markagunt Plateau, northwest Kane County, Utah: U.S. 

Geological Survey Miscellaneous Investigations Map 

1-494, scale 1:62,500.

____ 1967b, Carmel Formation of the Zion Park region,

southwestern Utah A review, in Contributions to

stratigraphy, 1966: U.S. Geological Survey Bulletin

1244-J, 9 p. 

Coope, B.M., and Harben, P.W., 1977, Silica sand, in Harben,

P.W., ed., Raw materials for the glass industry: New

York, Metal Bulletin Ltd., p. 15-38. 

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

Complete Bouguer gravity anomaly map of the Rio

Grande rift, Colorado, New Mexico, and Texas: U.S.

Geological Survey Geophysical Investigations Map

GP-949, scale 1:1,000,000. 

Davis, L.L., and Tepordei, V.V., 1985, Sand and gravel, in

Mineral facts and problems: U.S. Bureau of Mines

Bulletin 675, p. 689-703.

Doelling, H.H., and Graham, R.L., 1972, Southwestern Utah 

coal fields Alton, Kaiparowits Plateau, and KolobHarmony: Utah Geological and Mineralogical Survey 

Monograph Series No. 1, 333 p.

E22 Mineral Resources of Wilderness Study Areas Southwestern Utah
Giardina, Salvatore, Jr., 1979, Geologic review of northwestern 

Arizona for petroleum exploration investigations: Arizona Oil and Gas Conservation Commission Publication 

4, 72 p.

Goudarzi, G.H., compiler, 1984, Guide to preparation of 

mineral survey reports on public lands: U.S. Geological 

Survey Open-File Report 84-787, 42 p.

Gregory, H.E., 1950, Geology and geography of the Zion Park 

region, Utah and Arizona: U.S. Geological Survey 

Professional Paper 220, 200 p.

Hamilton, W.L., 1978, Geological map of Zion National Park, 

Utah: Springdale, Utah, Zion Natural History Association, scale 1:31,680.

____ 1984, The sculpturing of Zion: Springdale, Utah, Zion

Natural History Association, 132 p.

Heyl, A.V., 1978, Silver Reef, Utah, ores and the possibilities of 

unoxidized ores at greater depths, in Guidebook to 

mineral deposits of southwestern Utah: Utah Geological 

Association Publication 7, p. 65.

Hintze, L.F., 1973, Geologic history of Utah: Brigham Young 

University Geology Studies, v. 20, pt. 3, 181 p.

Irwin, C.D., 1976, Permian and Lower Triassic rocks of 

central Utah, in Guidebook to the geology of Utah: 

Intermountain Association of Petroleum Geologists, 

no. 7, p. 193-202.

Kreidler, T.J., 1986, Mineral investigation of a part of the 

Canaan Mountain Wilderness Study Area, Kane and 

Washington Counties, Utah (UT-040-143) and Mohave 

County, Arizona (AZ-020-041): U.S. Bureau of Mines 

Mineral Land Assessment Open File Report MLA 

43-86, 13 p.

Molenaar, C.M., and Sandberg, C.A., 1983, Petroleum 

potential of wilderness lands in Utah, in Miller, B.M., ed., 

Petroleum potential of wilderness lands in the Western 

United States: U.S. Geological Survey Circular 902-A-P, 

p. K1-K14.

Moyer, F.T., 1939, Gypsum and anhydrite: U.S. Bureau of 

Mines Information Circular IC-7049, 45 p.

Muffler, L.J.P., ed., 1978, Assessment of geothermal resources 

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

790, 163 p.

Oakes, Ed, Wedow, Helmuth, Poling, Robert, and Voelker, Al, 

1981, Energy-resource evaluation of wilderness study 

areas administered by the Bureau of Land Management: 

Oak Ridge, Tenn., U.S. Department of Energy, 317 p.

Peterson, Fred, and Pipiringos, G.N., 1979, Stratigraphic 

relations of the Navajo Sandstone to Middle Jurassic 

formations, southern Utah and northern Arizona: 

U.S. Geological Survey Professional Paper 1035-B, 

p. B1-B43.

Peterson, P.R., 1974, Anderson Junction field: Utah Geological 

and Mineral Survey Oil and Gas Field Studies, no. 13, 

3 p.

Poole, F.G., and Claypool, G.E., 1984, Petroleum source-rock 

potential and crude-oil correlation in the Great Basin, in 

Woodward, Jane, Meissner, F.F., and Clayton, J.L., eds., 

Hydrocarbon source rocks of the greater Rocky 

Mountain region: Denver, Colo., Rocky Mountain 

Association of Geologists, p. 179-229.

Proctor, P.D., 1953, Geology of the Silver Reef (Harrisburg) 

mining district, Washington County, Utah: Utah 

Geological and Mineralogical Survey Bulletin 44, 169 p.

Ryder, R.T., 1983, Petroleum potential of wilderness lands in 

Arizona, in Miller, B.W., ed., Petroleum potential of 

wilderness lands in the Western United States: U.S. 

Geological Survey Circular 902-A-P, p. C1-C22.

Sargent, K.A., and Philpott, B.C., 1985, Geologic map of the 

Johnson quadrangle, Kane County, Utah, and Coconino 

County, Arizona: U.S. Geological Survey Geologic 

Quadrangle Map GQ-1602, scale 1:62,500.

____1987, Geologic map of the Kanab quadrangle, Kane 

County, Utah, and Mohave and Coconino Counties, 

Arizona: U.S. Geological Survey Geologic Quadrangle 

Map GQ-1603, scale 1:62,500.

Stowe, Carlton, compiler, 1972, Oil and gas production in Utah 

to 1970: Utah Geological and Mineralogical Survey 

Bulletin 94, 179 p.

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

Principles of a resource/reserve classification for 

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

U.S. Department of Energy, 1979, National uranium resource 

evaluation, interim report: U.S. Department of Energy, 

Grand Junction Operations Report GJO-111(79), 137 p.

Van Loenen, R.E., Sable, E.G., Blank, H.R., Jr., Turner, R.L., 

Kreidler, T.J., Zelten, J.E., and Cook, K.L., 1988a, 

Mineral resources of the Canaan Mountain and The 

Watchman Wilderness Study Areas, Washington and 

Kane Counties, Utah: U.S. Geological Survey Bulletin 

1746-A, 26 p.

Van Loenen, R.E., Sable, E.G., Blank, H.R., Jr., Barton, H.N., 

Cook, K.L., and Zelten, J.E., 1988b, Mineral resources of 

the Parunuweap Canyon Wilderness Study Area, Kane 

County, Utah: U.S. Geological Survey Bulletin 1746-B, 

22 p.

Wilson, R.F., and Stewart, J.H., 1967, Correlation of Upper 

Triassic and Triassic(?) formations between southwestern Utah and southern Nevada, in Contributions to 

stratigraphy, 1966: U.S. Geological Survey Bulletin 

1244-D, p. D1-D20.

Zelten, J.E., 1987, Mineral investigation of eleven wilderness 

study areas adjacent to Zion National Park, southwestern 

Utah: U.S. Bureau of Mines Mineral Land Assessment 

Open File Report MLA 77-87, 55 p.

Zietz, Isidore, Shuey, Ralph, and Kirby, J.R., Jr., 1976, Aeromagnetic map of Utah: U.S. Geological Survey Geophysical Investigations Map GP-907, scale 1:1,000,000.

Eight Wilderness Study Areas Bordering Zion National Park E23

APPENDIX
DEFINITION OF LEVELS OF MINERAL RESOURCE POTENTIAL 

AND CERTAINTY OF ASSESSMENT

Definitions of Mineral Resource Potential

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

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

or no indications of having been mineralized.

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

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

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

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

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

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

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

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

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

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

moderate, or high levels of resource potential.

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

area.

Levels of Certainty

U/A

UNKNOWN

POTENTIAL

H/B

HIGH POTENTIAL

M/B 

MODERATE POTENTIAL

L/B

LOW

POTENTIAL

H/C

HIGH POTENTIAL

M/C 

MODERATE POTENTIAL

L/C

LOW

POTENTIAL

H/D

HIGH POTENTIAL

M/D 

MODERATE POTENTIAL

L/D

LOW POTENTIAL

N/D

NO POTENTIAL

t

o

Q.

Ul 

DC

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.
RESOURCE/RESERVE CLASSIFICATION

ECONOMIC

MARGINALLY 

ECONOMIC

SUBECONOMIC

IDENTIFIED RESOURCES

Demonstrated

Measured Indicated

1 

Reserves

Marginal Reserves

Demonstrated 

Subeconomic Resources

Inferred

Inferred Reserves

Inferred 

Marginal Reserves

Inferred 

Subeconomic 

Resources

UNDISCOVERED RESOURCES

Probability Range

 (or) 

Hypothetical i Speculative

I

+

1

1

Major elements of mineral resource classification, excluding reserve base and inferred reserve base. Modified from McKervey,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.
GEOLOGIC TIME CHART 

Terms and boundary ages used in this report

EON

Phanerozoic

Proterozoic

Archean 

pre-Arc

ERA

Cenozoic

Mespzoic

Paleozoic

Late Proterozoic

Middle Proterozoic

Early Proterozoic

Late Archean

Middle Archean

Early Archean 

hean2

PERIOD

Quaternary

Neogene 

Subperiod

Tertiary 

Paleogene 

Subperiod

Cretaceous

Jurassic

Triassic

Permian

Pennsylvanian 

Carboniferous

Periods 

Mississippian

Devonian

Silurian

Ordovician

Cambrian

 3800? -

EPOCH

Holocene

Pleistocene

Pliocene

Miocene

Oligocene

Eocene

Paleocene

Late 

Early

Late 

Middle 

Early

Late 

Middle 

Early

Late 

Early

Late 

Middle 

Early

Late 

Early

Late 

Middle 

Early

Late 

Middle 

Early

Late 

Middle 

Early

Late 

Middle 

Early

 -

BOUNDARY AGE 

IN 

MILLION YEARS

-0.010

- 1.7

- 5

- ^H

_ Gfi

- 96

OAC

-A, 240 

- 290

-~ 330

ocn

- 410

A OC

- 500 

- ~ 570'

- 900 

- 1600

 OdAA

-3000 

- 3400

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

2 Informal time term without specific rank.

frU.S. GOVERNMENT PRINTING OFFICE: 1989-673-047/66047