Petroleum Potential of 

Wilderness Lands in 

Washington 

By Thomas D. Fouch 

PETROLEUM POTENTIAL OF WILDERNESS LANDS IN THE 

WESTERN UNITED STATES 

GEOLOGICAL SURVEY CIRCULAR 902-L 

This chapter on the petroleum 

geology and resource potential of 

Wilderness Lands in Washington 

is also provided as an accompanying pamphlet for Miscellaneous 

Investigations Series Map 1-1546 

CONTENTS 

Page 

Abstract---------------------------------------------------------------------- Ll 

Introduction------------------------------------------------------------------- 1 

Purpose and methods ----------------------------------------------------------- 2 

Provinces and basins------------------------------------------------------------ 3 

Western Washington basin---------------------------------------------------- 3 

Cascade Range province ------------------------------------------------------ 3 

~ethowRiverbasin --------------------------------------------------------- 4 

Northeastern Washington province--------------------------------------------- 4 

Columbia River Basalt basin -------------------------------------------------- 4 

Yakima-Umatilla basin ---------------------------------------------~-------- 4 

Summary------------------------------------------------------------------ 5 

Referencescited---------------------------------------------------------------- 5 

ILLUSTRATION 

Page 

FIGURE 1. ~ap of Washington State showing location ofWilderness Lands, geologic provinces, and basins-------------- L2 

III 

PETROLEUM POTENTIAL OF WILDERNESS LANDS IN THE WESTERN UNITED STATES 

Petroleum Potential of Wilderness Lands in Washington 

By Thomas D. Fouch 

ABSTRACT 

The Wilderness Lands in the State of Washington cover 

nearly 4 million acres and are located principally in the area of 

the Cascade Range and in the Olympic Mountains in the northwest part of the State. Relatively small wilderness tracts occur 

in northeast and southeast Washington. The potential for other 

than trace or show amounts of oil and (or) gas in rocks underlying Wilderness Lands of the State are relatively low. 

Wilderness Lands in the Cascade Range are generally underlain by volcanic and plutonic igneous rocks and by metamorphic units of various grades. Relatively small areas in the Cascade Range province contain nonmarine sedimentary rocks, 

Tertiary in age, with little or no indigenous organic matter 

that could be thermochemically transformed into petroleumlike 

hydrocarbons. Reservoir rocks may be sparsely developed and 

source beds for the most part are thermochemically immature. 

Wilderness Lands in the Olympic Mountain range occur 

within the western Washington basin which is underlain by a 

sequence of Tertiary marine sedimentary rocks. Most of the 

organic matter in these basin rocks is thermochemically immature, but some rocks in the deeper parts of the basin are matured locally. Oil shows have been detected in drill holes and 

oil was recovered from wells in the vicinity of Grays Harbor. 

Oil seeps are also known in the western part of the Olympic 

Peninsula. Although the basin contains the primary elements 

of a petroleum province, the basin is at best sparsely explored 

and is a frontier area for petroleum exploration. 

The Wilderness Lands in the northeastern Washington province are primarily underlain by volcanic, sedimentary, and 

plutonic igneous rocks. The province has very low or zero petroleum potential. The remaining wilderness tracts occur in the 

central and southeastern part of the State in the Columbia 

River Basalt basin. The basin is characterized by basaltic igneous rocks of Neogene age that contain interbeds of nonmarine 

sedimentary rock rich in carbonaceous matter. Drill holes penetrating the sequence of basalt have detected gas and coal beds 

of lignitic rank. Gas was produced from the Rattlesnake gas 

field in the southern part of the basin. 

A qualitative assessment of the petroleum potential of the 

Wilderness Lands in Washington is reported by acreage as follows: a low potential of 952.4 thousand acres and a low to zero 

potential of 2,940.5 thousand acres, for a total of 3,892.9 

thousand acres. 

INTRODUCTION 

Wilderness Lands in the State of Washington 

are located principally in the area of the Cascade 

Ll 

Range and extend south from the Canadian border to the Oregon State border (fig. 1). A large 

area of Wilderness Land is located in the Olympic 

Mountains in the northwest part of the State. Relatively small wilderness tracts exist in northeast 

and southeast Washington. 

The potential for other than trace or show 

amounts of oil and (or) gas in rocks underlying 

wilderness areas of the State are relatively low. 

Wilderness Lands in the Cascade Range are generally underlain by plutonic, igneous, and small 

amounts of sedimentary rock that contains little or 

no indigenous organic matter that could be thermochemically transformed into petroleumlike hydrocarbons. Relatively small areas of Wilderness 

Land in the Cascades may contain some nonmarine sedimentary rocks that are carbonaceous, 

but the maturation state of this organic matter is 

thought to be too low to have yielded hydrocarbons. Near plutonic bodies, sedimentary rocks 

have been locally metamorphosed to a thermal 

state too high to have preserved petroleumlike 

compounds. 

Wilderness Lands in the Olympic Mountain region of northwest Washington are largely underlain by a sequence of Tertiary marine sedimentary 

rocks. These rocks contain terrestrial and marine 

sapropelic organic matter, but the maturation 

state of the matter is believed to be very low. 

Wilderness tracts of northeast Washington are 

underlain by crystalline rock and seem to have little potential to yield oil or gas. The wilderness 

tract in the southeast part of the State contains 

Tertiary lava flows that may contain interbedded 

carbonaceous and coaly nonmarine sedimentary 

rocks. These rocks could locally yield small 

amounts of methane where the organic matter has 

been transformed into gas either by bacterial action or by contact thermal metamorphism where 

extrusive igneous lava came into contact with 

rocks rich in organic matter. 
0 

N 

t 

6 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

4 /"\ / '/ \/ 

NORTHEASTERN WASHINGTON 

PROVINCE 

\ 

5 

COLUMBIA RIVER 

BASALT BASIN 

EXPLANATION 

PETROLEUM POTENTIAL: 

' . 

WESTERN 

WASHINGTON 

BASIN YAKIMA-UMATILLA \ ~Low 

'" 2),;1 Low to zero BASIN \ 

\ 

\ J!t;p _____________ .--L.~~---___J 

100 MILES 

FIGURE 1.-Map of Washington State showing location of Wilderness Lands. Provinces and basins shown are (1) Western 

Washington basin, (2) Cascade Range Province, (3) Methow River basin, (4) Northeastern Washington province, (5) Columbia River Basalt basin, and (6) Yakima-Umatilla basin. 

PURPOSE AND METHODS 

The purpose of this paper is threefold: (1) to 

present a brief geologic characterization of rocks 

underlying wilderness areas in the State of 

Washington emphasizing those properties that can 

be related to evaluating the petroleum potential of 

the rocks for yielding hydrocarbons; (2) to indicate 

some of the publicly available data that can be utilized in assessing the petroleum potential of Wilderness Lands; and (3) to present a reconnaissance qualitative assessment of the potential of 

rocks in Wilderness Lands to yield other than 

show or trace amounts of petroleum. The assessments are based on publicly available data so that 

the assessments may be independently evaluated. 

For purposes of this assessment of the petroleum potential of Wilderness Lands in 

Washington, rocks of the State are separated 

geographically into six provinces or basins in 

L2 

which the geologic elements are similar (fig. 1). 

Boundaries among the provinces and basins are 

approximately, and in some cases arbitrarily, 

drawn because the areal and subsurface extent of 

many of the important geologic units is uncertain. 

Of primary concern is the recognition of the presence and character of potential reservoir, source, 

and trapping units for petroleum, the principal ingredients of a petroleum province. Because oil and 

gas have been recovered only locally in the State, 

the petroleum potential of frontier nonproductive 

regions is estimated largely by identifying the 

presence or absence of organic matter in the rocks 

(i.e., coal, carbonaceous shale, or reports of fetid 

odor) and estimating the level of maturation of the 

organic compounds. Values of coal rank (Beikman 

and others, 1961; Walsh and Phillips, 1982) and 

vitrinite and Rock-Eval data (T. D. Fouch and D. 

A. Anders, 1981, unpublished data) provided the 

principal indices of thermochemical maturation. 

These indices were related to the major stages of 
thermochemical maturation of organic matter into 

oil or gas by using the data summarized by Bostick (1979). 

A qualitative estimate of the petroleum potential of the Wilderness Lands of Washington is provided by using the terms low or low to zero. 

Potential is used herein to indicate the expectation 

of detecting liquid and (or) gaseous hydrocarbons 

in other than trace amounts. Expressions of potential, such as low, medium, or high are relative to 

other areas in the State of Washington and may 

not equate to an expression of potential in a different hydrocarbon province. A map of Washington 

has been prepared at a scale of 1:1,000,000 which 

shows the petroleum potential of Washington's 

Wilderness Lands (Miscellaneous Investigations 

Series Map 1-1546, in press). 

PROVINCES AND BASINS 

WESTERN WASHINGTON BASIN 

The Western Washington basin is underlain 

principally by Paleogene and Neogene clastic 

sedimentary rocks formed primarily from sediments deposited in littoral to deep marine depositional settings. Basaltic volcanic units formed on 

the submarine floor of the Eocene ocean are nearly ubiquitous as are local accumulations of volcaniclastic sedimentary rocks formed in association with the volcanic rocks. Along the eastern 

margin of the basin, marine strata grade laterally 

into nonmarine rocks that locally contain coal. The 

nonmarine sedimentary rocks were formed from 

sediments deposited by streams flowing generally 

to the west. These streams were locally impounded to form wetlands along a north-south 

coastal plain (Buckovic, 1979). Herbaceous and 

woody plant material accumulated in the wetlands 

and was later transformed into carbonaceous rock 

and coal. Much of the terrestrial organic matter 

was flushed by the subaerial streams from the 

wetlands and washed into the sea and was further 

distributed to sites well removed from the 

coastline by marine processes. 

Rock-Eval analyses (T. D. Fouch, and D. A. 

Anders, 1981, unpublished data) indicate that 

much of the organic matter recovered from both 

marine and nonmarine rocks in the basin was derived from terrestrial plants. However, sapropelic 

organic matter, which is a potential source of oil, 

has been detected in several areas of the basin in 

drill holes that penetrated marine shale units. 

L3 

Snavely and others (1977) indicate that some samples of Tertiary rocks from drill holes and surface 

exposures contain organic matter that can yield 

petroleumlike hydrocarbons upon maturation. 

Most of the organic matter in basin rocks is thermochemically immature, but some rocks from the 

deepest parts of the basin have been matured locally due to heating under a thick sequence of 

younger beds or by contact metamorphism with 

volcanic magmas. 

Oil shows have been detected locally in drill 

holes, and oil was recovered from wells in the vicinity of Grays Harbor on the central part of the 

Washington coast (McFarland, 1981). Oil seeps 

from Oligocene and Miocene rocks are also known 

from the western part of the Olympic Peninsula 

(Braislin and others, 1971). 

Arkosic sandstone reservoir beds of late Eocene 

and early Oligocene age are exposed in the southeast part of the basin. These same units yield gas 

at Mist field in northwest Oregon. These reservoir 

rocks can reasonably be expected to be penetrated 

in southwest Washington, but their areal extent is 

uncertain. Snavely and others (1977) give values 

of porosity and permeability for some beds encountered on surface exposures and in drill holes 

in Oregon and Washington. Wurden and Ford 

(1976) described Paleogene sandstones in the subsurface of the west-central part of the basin that 

are of such high reservoir quality that the units 

are utilized for underground storage of natural gas 

by a local utility company. These data indicate reservoir rocks are developed in the basin. 

Although the basin contains the primary elements of a petroleum province, (source, reservoir, 

and trapping elements), the basin is at best 

sparsely explored and is a frontier area for petroleum exploration. 

CASCADE RANGE PROVINCE 

This province is principally underlain by volcanic and plutonic igneous rocks and by metamorphic units of various grade. Relatively small areas 

of the province contain sedimentary rocks that 

were formed largely in nonmarine aquatic depositional setting in the Neogene and Holocene. Some 

areas contain sparse Paleogene nonmarine 

sedimentary rocks that are rich in carbonaceous 

organic matter. Near the northeastern part of the 

province, Paleogene sedimentary rocks contain 

coaly beds, but the beds are not believed to be 

buried deeply in the subsurface of the province. 
Reservoir rocks for hydrocarbons may be 

sparsely developed. Most potential reservoir rocks 

are composed of arkosic and lithic sandstones that 

have been variably altered to contain a variety of 

mineral cements that have largely reduced 

original porosity in the rocks to a very low value, 

a value perhaps too low to be a hydrocarbon reservoir rock. 

Values of maturation of organic matter in 

sedimentary rocks of the province are highly variable. Paleogene and some Neogene units that border plutonic and other igneous units have been 

heated to stages of maturation beyond the range 

of stable liquid hydrocarbons, and in some cases 

gaseous hydrocarbons. Some Neogene and virtually all younger units are thermochemically immature for the generation of either gaseous or liquid 

hydrocarbons. Some methane may have been generated locally in very young rocks by bacterial action. 

METHOW RIVER BASIN 

Rocks of the Methow River basin are principally 

of Mesozoic and Cenozoic age and are of both a 

sedimentary and igneous origin. Cretaceous black 

marine shale, dense sandstone, and igneous units 

are locally abundant. Paleogene rocks in the basin 

contain carbonaceous shales. 

Older Mesozoic rocks and some Cretaceous 

units have undergone at least the incipient stages 

of mineral metamorphism. In addition, vitrinite 

and Rock-Eval analyses of basin rocks indicate 

that all Mesozoic strata have been thermochemically matured beyond the range of stable hydrocarbons (T. D. Fouch, D. A. Anders, and M. J. 

Pawlewicz, unpublished data). 

Analyses of the maturation of organic matter 

and the sparse development of reservoir units indicate that the potential for detecting hydrocarbons in the basin is low to zero. Potential source 

beds for oil and (or) gas may be developed in 

Paleogene strata, but the units are not known to 

be buried deeply in the basin's subsurface. 

NORTHEASTERN WASHINGTON PROVINCE 

This province is primarily underlain by volcanic, 

sedimentary, and plutonic igneous rocks. Some 

pre-Tertiary strata are metamorphosed. The distribution of sedimentary rocks is only partially 

documented, but they may be present in the subsurface beyond areas of exposure. Coal is locally 

L4 

developed but does not seem to be present near 

Wilderness Lands. The province has very low or 

zero petroleum potential. 

COLUMBIA RIVER BASALT BASIN 

This basin is characterized by the nearly 

ubiquitous development of basaltic igneous rocks 

of Neogene age that contain interbeds of nonmarine sedimentary rock rich in carbonaceous 

matter. Paleogene nonmarine sedimentary rocks 

that originated in a system of locally drained basins contain thick sequences of coal. Ancient lake 

beds exposed west of the basin may have been 

formed in lakes hospitable for the generation and 

preservation of lipid-rich organic matter, but this 

relation is speculative. Early Paleogene sedimentary rock sequences contain some interbeds of volcanic flow rocks where exposed. Most of the surface of the basin is underlain by volcanic strata. 

Drill holes that penetrate the sequences of 

basalt have detected gas and coal beds of lignitic 

rank. Gas was produced from the Rattlesnake gas 

field in the southern part of the basin. Reservoir 

beds at the Rattlesnake field are fluvial and lacustrine sandstone units that are intercalated with 

coal in a sedimentary complex formed within the 

thick sequences of Neogene basalt. At least one 

drill hole has penetrated deeply buried Paleogene 

sedimentary and volcanic rocks beneath theN eogene units. These nonmarine beds are probably 

of Eocene and Oligocene age. 

YAKIMA-UMATILLA BASIN 

The basin is underlain by Paleogene and N eogene sedimentary and volcanic rocks that locally 

reach a thickness of greater than 6,000 meters. 

Mesozoic sedimentary rocks are exposed north 

and south of the basin, but their development in 

the subsurface of this basin remains speculative. 

Paleogene sedimentary rocks are rich in organic 

matter that apparently formed in ancient basins with 

internal drainage. Lithic and arkosic sandstone 

and conglomerate beds formed from clastic debris 

shed off the topographically high features and 

formed fans that developed peripheral to the central part of the depositional and topographic basin 

(Frizzell, 1979). Analyses of the sedimentary 

rocks indicate wetlands with small lakes developed at the basin center. Swamps with herbaceous and woody plants dotted the wetland terrane. Open lake water received herbaceous and 
• 

woody plant material washed into the water from 

peripheral settings. 

Neogene units are principally nonmarine fluvial, 

swamp, and volcanic units. Basalt is the dominant 

rock type, but it is principally developed along the 

basin's eastern margin. 

Drill holes have penetrated Paleogene sedimentary and volcanic units that yield numerous shows 

of natural gas. The Eocene and Oligocene rocks 

have yielded noncommercial quantities of gas and 

some water where penetrated on possible structural traps. 

Beikman and others (1961) give coal rank and 

other analyses of the coaly strata in the region 

that indicate exposed coals are of a rank that 

could yield gas upon thermochemical maturation. 

Indices of maturation from coal, Rock-Eval, and 

vitrinites analyses (T. D. Fouch, D. A. Anders, 

and M. J. Pawlewicz, unpublished data) indicate 

basin sedimentary rocks are thermochemically 

metamorphosed beyond the range of stable hydrocarbons only locally near igneous plutonic and flow 

rocks. These same data indicate that all of the 

analyzed units rich in organic matter contain terrestrial woody tissue. The presence of lipid-rich 

source rocks capable of yielding petroleumlike hydrocarbons is not documented. 

Reservoir rock development in the basin may be 

the limiting factor for accumulation of other than 

very small amounts of hydrocarbons. Fractured 

volcanic rocks or porous interbeds seem to indicate reservoir units with fracture permeability 

are developed in Neogene strata. However, Paleogene reservoir rocks may be very limited andare 

not yet known to contain hydrocarbons in other 

than show amounts in the subsurface. 

SUMMARY 

Of the 3,892,921 acres included in this study for 

the assessment of the petroleum potential of the 

Wilderness Lands in Washington, the potential 

acreage can be summarized as follows: low potential, 952.4 thousand acres; and low to zero potential, 2,940.5 thousand acres. The petroleum potential by acreage of all Wilderness Land categories 

in theW estern United States is shown in this circular by B. M. Miller in table 1, chapter P. 

REFERENCES CITED 

Beikman, H. M., Gower, H. D., and Dana, T. A. M., 1961, 

Coal reserves of Washington: Washington Division of 

Mines and Geology Bulletin No. 47, 115 p. 

Braislin, D. B., Hastings, D. D., and Snavely, P. D., Jr., 1971, 

Petroleum potential of western Oregon and Washington, 

and adjacent continental margin, in Cram, I. H., ed., Future Petroleum Provinces of the United States-Their 

Geology and Potential: American Association of Petroleum 

Geologists Memoir 15, v. 1, p. 229-238. 

Bostick, N. H., 1979, Microscopic measurements of the level of 

catagenesis of solid organic matter in sedimentary rocks to 

aid exploration for petroleum and to determine former burial temperatures-a review, in Scholle, P. A., and 

Schluger, P. R., Aspects of Diagenesis: Society of 

Economic Paleontologists and Mineralogists Special Publication 25, p. 17-44. 

Buckovic, W. A., 1979, The Eocene deltaic system of west-central Washington, in Armentrout, J. M., Cole, M. R., and 

Terbest, H. A., Jr., eds., Cenozoic paleogeography of the 

Western United States, Pacific Coast Paleogeography 

Symposium 3, Pacific Section: Society of Economic Paleontologists and Mineralogists, p. 147-163. 

Frizzell, V. A., 1979, Petrology of Paleogene sandstone units 

in Washington, in Armentrout, J. M., Cole, M. R., and 

Terbest, H. A., Jr., eds., Cenozoic paleogeography of the 

Western United States, Pacific Coast Paleogeography 

Symposium 3, Pacific Section: Society of Economic Paleontologists and Mineralogists, p. 113-118. 

McFarland, C. R., 1981, Oil and Gas Exploration in 

Washington 19~1981: State of Washington, Division of 

Mines and Geology Information Circular 67R, 119 p. 

Snavely, P. D., Jr., Pearl, J. E., and Lander, D. L., 1977, Interim report on petroleum potential and geologic hazards 

in the Outer Continental Shelf-Oregon and Washington 

Tertiary Province: U.S. Geological Survey Open-File Report 77-282, tables 2, 3, and 4. 

Walsh, T. J., and Phillips, W. M., 1982, Coal rank and thermal 

maturation in King County, Washington: Washington 

Geologic Newsletter, Washington Division of Geology and 

Earth Resources, v. 10, no. 1, p. 9-18. 

L5 

Wurden, F. H., and Ford, D. M., 1976, Appendix A, Jackson 

Prairie gas storage project, Chehalis, Washington, in 

Newton, V. C., Jr., and VanAtta, R. 0., eds., Prospects' 

for natural gas production and underground storage of 

pipe-line gas in the upper Nehalem River basin, ColumbiaClatsop Counties, Oregon: Oregon Department of Geology 

and Mineral Industries, Oil and Gas Investigations 5, p. 

37-41.