U.S. Department of the Interior

U.S. Geological Survey

Pamphlet to accompany

Scientific Investigations Map 3266

Maps Showing Thermal Maturity of Upper Cretaceous 

Marine Shales in the Wind River Basin, Wyoming
COVER. Upper part of the Cody Shale at Eagle Point, Wyo., in the northwestern part of the 

Wind River Basin. Photograph by R.C. Johnson, 1994.
Maps Showing Thermal Maturity of Upper 

Cretaceous Marine Shales in the Wind 

River Basin, Wyoming

By Thomas M. Finn and Mark J. Pawlewicz

Scientific Investigations Map 3266

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

SALLY JEWELL, Secretary

U.S. Geological Survey

Suzette M. Kimball, Acting Director

U.S. Geological Survey, Reston, Virginia: 2013

For more information on the USGS—the Federal source for science about the Earth, its natural and living 

resources, natural hazards, and the environment, visit http://www.usgs.gov or call 1–888–ASK–USGS.

For an overview of USGS information products, including maps, imagery, and publications, 

visit http://www.usgs.gov/pubprod

To order this and other USGS information products, visit http://store.usgs.gov

Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the 

U.S. Government.

Although this report is in the public domain, permission must be secured from the individual copyright owners to 

reproduce any copyrighted materials contained within this report.

Suggested citation:

Finn, T.M., and Pawlewicz, M.J., 2013, Maps showing thermal maturity of Upper Cretaceous marine shales in 

the Wind River Basin, Wyoming: U.S. Geological Survey Scientific Investigations Map 3266, 13 p., 1 sheet, scale 

1:500,000, http://dx.doi.org/10.3133/sim3266.

ISSN 2329-132X (online)
iii

Contents

Introduction.....................................................................................................................................................1

Stratigraphy ....................................................................................................................................................1

Mowry Shale..........................................................................................................................................1

Frontier Formation.................................................................................................................................1

Cody Shale .............................................................................................................................................6

Thermal Maturity Maps ................................................................................................................................7

Acknowledgments.......................................................................................................................................10

References....................................................................................................................................................10

Figures

1. Map of the Rocky Mountain region showing Laramide basins ............................................2

2. Index map of the Wind River Basin ...........................................................................................3

3. Stratigraphic chart of Upper Cretaceous rocks in the Wind River Basin...........................4

4. Regional stratigraphic cross section of Cretaceous rocks ...................................................5

5. Type log of Exxon Corp. Poison Springs Unit 1 ........................................................................6

6. Log (Ro) versus depth plot for the Coastal Oil and Gas 3-8-36-86 Bullfrog Unit well .........8

7. South-north structural cross section, central Wind River Basin .........................................9

Sheet

Sheet with maps showing thermal maturity of upper Cretaceous marine shales in the 

Wind River Basin, Wyoming.................................................................................................................... link

1. Map showing vitrinite reflectance at the top of the Cody Shale, Bighorn 

Basin, Wyoming and Montana.

2. Map showing vitrinite reflectance at the top of the lower shaly member 

of the Cody Shale.

3. Map showing vitrinite reflectance at the top of the Mowry Shale.
iv

Multiply By To obtain

Volume

cubic foot (ft3) 0.02832 cubic meter (m3) 

Area

square mile (mi2) 2.590 square kilometer (km2) 

Multiply By To obtain

Length

millimeter (mm) 0.03937 inch (in.)

Area

square meter (m2) 0.0002471 acre 

square kilometer (km2) 0.3861 square mile (mi2)

Altitude, as used in this report, refers to distance above Sea Level.

Inch/Pound to SI

SI to Inch/Pound

Conversion Factors
Introduction

The Wind River Basin is a large Laramide (Late Cretaceous through Eocene) structural and sedimentary basin that 

encompasses about 7,400 mi2 in central Wyoming (fig. 1). 

The basin is bounded by the Washakie Range, Owl Creek, and 

southern Bighorn Mountains on the north, the Casper arch on 

the east and northeast, the Granite Mountains on the south, and 

the Wind River Range on the west (figs. 1, 2).

Important conventional and unconventional oil and gas 

resources have been discovered and produced from reservoirs 

ranging in age from Mississippian through Tertiary (Keefer, 

1969; Fox and Dolton, 1989, 1996; De Bruin, 1993; Johnson 

and others, 1996, 2007). It has been suggested that various 

Upper Cretaceous marine shales are the principal hydrocarbon 

source rocks for many of these accumulations (Keefer, 1969; 

Meissner and others, 1984; Fox and Dolton, 1989, 1996; Johnson and Rice, 1993; Nuccio and others, 1996; and Schelling 

and Wavrek, 1999, 2001). Numerous source rock studies of 

various Upper Cretaceous marine shales throughout the Rocky 

Mountain region by various authors, including Schrayer 

and Zarrella (1963, 1966, 1968), Nixon (1973), Clayton and 

Swetland (1977), Merewether and Claypool (1980), Burtner 

and Warner (1984), Hagen and Surdam (1984), Momper and 

Williams (1984), Davis (1986), Davis and others (1989), 

Nuccio (1990a,b), Longman and others (1998), Landon and 

others (2001), Roberts and others (2004, 2007, 2008), and 

Finn (2007a, 2010), have led to the conclusion that these rocks 

have generated, or are capable of generating, oil and (or) gas. 

With recent advances and success in horizontal drilling and 

multistage fracture stimulation there has been an increase in 

exploration and completion of wells in these marine shales in 

other Rocky Mountain Laramide basins that were traditionally thought of only as hydrocarbon source rocks (Sterling and 

others, 2009; Sonnenberg, 2011). Important parameters that 

control hydrocarbon production from shales include: reservoir 

thickness, amount and type of organic matter, and thermal 

maturity (Milici, 1993; Curtis, 2002; Passey and others, 2010). 

The purpose of this report is to present maps and a structural 

cross section showing levels of thermal maturity, based on 

vitrinite reflectance (Ro), for Upper Cretaceous marine shales 

in the Wind River Basin.

Stratigraphy

Figure 3 is a correlation chart showing the stratigraphic 

nomenclature for Upper Cretaceous marine shales and associated rocks in the Wind River Basin (Finn, 2007b) and correlative units in various localities in the Powder River Basin to the 

east (Merewether, 1996). The stratigraphic relationships and 

nomenclature for the Wind River Basin are also illustrated on 

the regional stratigraphic cross section in figure 4.

Mowry Shale

According to Keefer and Johnson (1997), the Mowry Shale 

in the Wind River Basin is characterized by two distinct units 

(fig. 5). The lower part consists of 50 to 150 ft of soft fissile 

clay-rich shale that has been referred to as the Shell Creek Shale 

in the adjacent Bighorn and Powder River Basins (Eicher, 1962; 

Burtner and Warner, 1984). The upper part is composed of 200 

to 350 ft of hard brittle siliceous shale, with numerous bentonite 

beds (Keefer and Johnson, 1997). The shales are dark brown 

to black, organic-rich, and contain an abundance of fish scales 

(Burtner and Warner, 1984). The bentonites are gray to tan and 

range in thickness from less than an inch to as much as 6.5 ft 

(Byers and Larson, 1979). The top of the Mowry is considered 

to be the Clay Spur Bentonite Bed; the base is the contact with 

the underlying Muddy Sandstone (fig. 5). The combined thickness of the lower and upper units ranges from about 220 ft in the 

southeastern part of the basin to more than 500 ft in the western 

part. Paleontologic evidence and radiometric dating indicates 

that the formation is mainly early Late Cretaceous (Cenomanian) in age (Cobban and Kennedy, 1989; Merewether and 

others, 1997; Obradovich and others, 1996), but the lower part 

(Shell Creek Shale equivalent) has been dated radiometrically 

as Early Cretaceous (Albian) by Obradovich and others (1996). 

For convenience, all of the formation will be discussed with the 

Upper Cretaceous in this report.

Frontier Formation

The Frontier Formation consists of alternating sandstone, 

shale, and bentonite that accumulated in marine and marginal 

marine environments (Keefer, 1972). In the western part of 

Maps Showing Thermal Maturity of Upper Cretaceous 

Marine Shales in the Wind River Basin, Wyoming

By Thomas M. Finn and Mark J. Pawlewicz
2 Maps Showing Thermal Maturity of Upper Cretaceous Marine Shales in the Wind River Basin, Wyoming

Figure 1. Map of Rocky Mountain region extending from southern Montana to northern 

New Mexico showing locations of Laramide sedimentary and structural basins (in brown) and 

intervening uplifts. Modified from Dickinson and others (1988).

112° 110° 108° 106° 104°

46°

44°

40°

36o

MONTANA

WYOMING

IDAHO

MONTANA

IDAHO

UTAH

COLO

CO

ARIZ

UT

N. MEX

Black Hills uplift

Crazy

Mountains

Basin

Bull

Mountains

Basin

Greater Green

River Basin

Laramie

Hanna Basin

Basin

Hartville uplift

Rawlins

uplift

Uinta uplift

Wind

River

uplift

White

 River

 uplift

Gunnison

uplift

Nacimiento uplift

(Neogene)

 Grande 

Park

Range

uplift

Sierra Madre

uplift

Uncompahgre

uplift

Bridger

uplift

Beartooth

uplift

San Rafael

Swell

Medicine

Bow

uplift

Shirley

Basin

North and Middle

Park Basins

South Park

Basin

Sawatch uplift

Front

Range

uplift

San Juan

uplift

Axial Basin uplift

Teton

uplift

Thrust or reverse fault

Cordilleran orogenic belt

38o

42°

WYOMING

Casper arch

arch

Reed Point

syncline

PRYOR

MOUNTAINS

Nye-Bowler

lineament

Zuni uplift

EXPLANATION

San Juan

Basin

Uinta

Basin

Piceance

 Basin

Bighorn Basin

Wind River Basin

Sangre de Cristo uplift

Granite Mountains

uplift

Owl Creek uplift

Miles City 

COLORADO

NEW MEXICO

0

0 50 100 KILOMETERS

50 100 MILES

Rio

rift

N. DAK

S. DAK

S. DAK

NEBRASKA

WYO NEB

Powder

River

Basin

Bighorn uplift

Absaroka

volcanic field

San

Juan

volcanic

field

Raton

Basin

Basin

Denver
EXPLANATION

Wind River Basin Province

boundary

R 105 W

R 110 W

T

40

N

R 5 W

R 100 W

R 1 W R 1 E

T5

N

R 5 W

R 95 W

R 5 E

T1

N

T1

S

R 1 W

T5

N

T1

N

R 1 E

T

30

N

R 100 W

R 5 E

T1

S

T

40

N

R 95 W

T

30

N

R 90 W R 85 W

Washakie Range

Wind

River

Range

Mountains

Creek

Owl

Bighorn Mountains

CASPER

Granite

Mountains

0 10 20 30 40 MILES

0 10 20 30 40 KILOMETERS

Wind River Basin

Province Boundary

43o

110o 109o 108o 107o

5000

5000

50000 -5000 -10000

-15000

0

-15000

-15000

5000

0

5000

0 -10000

-10000

-5000

-5000

Basin

Basin

axis

axis

Madden anticline

Line of section (see fig. 7)

High-angle fault

Thrust fault—Sawteeth on

upper plate

Syncline—Large arrowhead

shows direction of plunge

Anticline—Large arrowhead

shows direction of plunge

Precambrian rocks

Frontier Formation

Figure 2. Index map of the Wind River Basin in central Wyoming showing major structural and physiographic features. Structure contouFrontier Formation. Contour interval 5,000 ft.
Figure 3. Correlation chart showing stratigraphic relations of lowermost Upper Cretaceous rocks in the Wind River Basin and correlation with equivRiver Basin. Modified from Merewether (1996) and Finn (2007b). Radiometric ages and fossil zones are from Obradovich (1993), and Merewether and Cretaceous.

Ma

80

859095

Fossil zone

U Upper Upper Upper Upper Lower L Lower Middle Middle Middle Middle L L M

UPPER CRETACEOUS (part)

Campanian (part) Santonian Coniacian Turonian Cenomanian

Didymoceras nebrascense

Baculites scotti

Baculites gilberti

Baculites perplexus (late form)

Baculites gregoryensis

Baculites reduncus

Baculites perplexus (early form)

Baculites sp. (smooth)

Baculites asperiformis

Baculites obtusus

Baculites mclearni

Scaphites hippocrepis III

Baculites sp. (smooth) Baculites sp. (weak flank ribs)

Scaphites hippocrepis II

Scaphites hippocrepis I

Desmoscaphites bassleri

Desmoscaphites erdmanni

Clioscaphites choteauensis

Clioscaphites vermiformis

Clioscaphites saxitonianus

Scaphites depressus

Inoceramus involutus

Inoceramus deformis Inoceramus erectus

Prionocyclus quadratus

Prionocyclus percarinatus

Prionocyclus hyatti

Prionocyclus macombi

Prionocyclus wyomingensis

Scaphites whitfieldi

Collignoniceras woollgari

Mammites nodosoides

Vascoceras birchbyi Pseudaspidoceras flexuosum

Nigericeras scotti

Burroceras clydense

Dunveganoceras problematicum

Plesiacanthoceras wyomingense

Acanthoceras bellense

Acanthoceras granerosense Colinoceras tarrantense

Neogastroplites haasi

Neogastroplites muelleri

Neogastroplites maclerni

Eastern Wind River

Basin

Western Wind River

Basin

Southern and central

Wind River Basin

Fales Sandstone Member

Parkman Sandstone Member

Wallace Creek Tongue

of Cody Shale

Cody Shale

Cody Shale

Steele Member Conant Creek tongue of Cody Shale Alkali Butte member

Cody Shale

Cody Shale

CRETACEOUS (part)

Mowry Shale Mowry Shale Mowry Shale

Frontier Formation

Albian

(part) 100 Muddy Sandstone Muddy Sandstone Muddy Sandstone

Mowry Shale

Muddy Sandstone

Frontier Formation

Frontier Formation

Frontier Formation

Belle Fourche

Member

Emigrant Gap

Member

Emigrant Gap

Member

Wall Creek Member Wall Creek Member

Unnamed

upper part

Unnamed

lower part

Niobrara Member

Niobrara Formation

(equiv.)

Sage Breaks Member

Sussex and

Shannon Ss. Beds

Wall Creek Member

Belle Fourche

Member

Emigrant Gap Member

Belle Fourche

Member

Emigrant Gap Member

Wall Creek Member

Upper sandy

member

Upper sandy

member

Upper sandy

member

Lower shaly

member Lower shaly member Lower shaly member

Basal sandstone member

?

83.586.388.793.398.5

System Series Stage

Mesaverde

Formation

(part)

Mesaverde Formation

(part)

Mesaverde

Formation

(part)

Western Powder

River Basin

Belle Fourche

Member 

Mesaverde

Formation

(part)

"chalk kick" "chalk kick" "chalk kick"

LK

(part)

CRETACEOUS (part)

UPPER CRETACEOUS (part)
Figure 4. Regional northwest-southeast stratigraphic cross section of Cretaceous rocks (part) in the Wind River Basin. Modified from Finn (2007b).

Meeteetse Formation (part)

Meeteetse Formation (part)

Mesaverde Formation

Teapot Sandstone Member Parkman Sandstone 

Fr

Wal

Fales Sandstone Member

"Sussex sands"

"Shannon sands"

Conant Creek tongue

Alkali Butte member

Frontier Formation

Mowry Shale

Cloverly Formation

Unnamed middle

member

Unnamed middle member

Muddy Sandstone

Muddy Sandstone

Lew

NORTHWEST 

Clay Spur Bentonite Bed

Basal sandstone

member

"chalk kick"

Coalbank Hills Castle Gardens

Alkali Butte

Shotgun

Butte

Thermopolis Shale

Upper Cretaceous

Lower

Cretaceous

Jurassic

? ?

"glauconitic sandstone"

Lower shaly member

Upper sandy member

Upper sandy member

Cody Shale

Cody S

"Niobr

"Carlile shale equivalent"

Jurassic rocks undivided

(part)

0 5 10 15 20 MILES

0

500

FEET

1,000 NW

Locati

Fluvial sandstone

and conglomerate

Marine and marginal marine

sandstone and siltstone

Fluvial and estuarine sandstone

Interbedded sandstone and

shale, marine

Coastal plain and floodplain

Marine shales sandstones, shales, and coals

Undifferentiated depositsStratigraphic marker beds from well logs

EXPLANATION

Unconformity

W
6 Maps Showing Thermal Maturity of Upper Cretaceous Marine Shales in the Wind River Basin, Wyoming

the basin, the Frontier also contains some nonmarine rocks, 

including minor coal deposits. Sandstones generally dominate 

in the upper part of the formation, whereas the lower part is 

mostly marine shale. Many individual sandstones are blanketlike and can be traced over several miles, but locally may be 

discontinuous and pinch out into marine shale. The shales are 

generally sandy or silty and vary from gray to black in color. 

The formation is Cenomanian to Coniacian in age (Merewether 

and others, 1997) and ranges in thickness from 400 to 800 ft.

Cody Shale

The Cody Shale consists of marine shale, siltstone, and 

sandstone that were deposited during a major transgressiveregressive cycle that Kauffman (1977) referred to as the 

“Niobrara Cyclothem.” According to Johnson and others 

(2007) the formation ranges in thickness from about 3,250 ft 

in the western part of the basin to more than 5,500 ft in the 

eastern part. The lower and upper contacts are conformable 

and interfinger with the underlying Frontier and overlying 

Mesaverde Formations (fig. 4). Four members are recognized 

in ascending order: (1) the lower shaly member (Thompson 

and White, 1954; Yenne and Pipiringos, 1954; and Keefer and 

Troyer, 1964), (2) the upper sandy member (Thompson and 

White, 1954; Yenne and Pipiringos, 1954; Keefer and Troyer, 

1964), (3) the informally named “Conant Creek tongue” 

(Szmajter, 1993), and (4) the Wallace Creek Tongue (Barwin, 

1961) (fig. 4). The age of the Cody ranges from Coniacian to 

middle Campanian (Keefer, 1972).

The unnamed lower shaly member is about 1,750 ft thick 

in the western part of the Wind River Basin and thickens to 

the east to more than 2,250 ft (Johnson and others, 2007). It 

is comprised of gray to black shale and bentonite deposited in 

an offshore marine environment. A persistent geophysical-log 

marker in the lower 100–300 ft of the lower member (fig. 5), 

referred to as the “chalk kick” by Keefer (1972), can be traced 

in the subsurface throughout most of the basin; it separates 

noncalcareous shales in the lower part of the shaly member 

from overlying calcareous shales. Based on sample descriptions from well cuttings, the calcareous interval is about 1,000 

ft thick in the eastern part of the basin where Merewether and 

others (1977a, b) correlated it with the Niobrara Formation 

in the Powder River Basin (fig. 3). They (Merewether and 

others, 1977a, b) correlated the interval below the “chalk kick” 

marker and the top of the uppermost sandstone in the Frontier 

Formation with the Carlile Shale in the Powder River Basin 

(figs. 4, 5). In the eastern part of the Wind River Basin the 

Niobrara-equivalent rocks are of Coniacian to latest Santonian 

or earliest Campanian age. To the west, the upper part of the 

interval grades into the sandy and shaly facies of the upper 

sandy member of the Cody Shale and only the basal Niobrara 

strata of the Powder River Basin are represented by the lower 

shaly member (fig. 4). In the western part of the Wind River 

Basin, rocks assigned to the shaly member are Coniacian to 

early Santonian in age (Yenne and Pipiringos, 1954; Keefer, 

1972; Finn, 2007b).

10,000

10,500

11,000

11,500

12,000

12,500

13,000

GR Res.

"chalk kick

marker"

Clay Spur

Bentonite

Upper Cretaceous (part)

Muddy Sandstone

Thermopolis Shale

Mowry

Shale

Frontier

Formation

Cody Shale (part)

Lower shaly member

Upper sandy

member

(part)

Carlile

Shale

equivalent

Upper

siliceous

part

Lower part Basal Niobrara Formation equivalent

Cloverly Formation

Lower

Cretaceous

?

Exxon Corp. Poison Springs Unit 1

sec. 33, T. 32 N., R. 83 W.

Figure 5, Type log of Exxon Corp. Poison Springs Unit 1, of the 

lower and lowermost Upper Cretaceous rocks in the southeastern 

part of the Wind River Basin. Sandstones and conglomerates of 

predominantly fluvial origin are shown in red; marine and marginal 

marine sandstones and siltstones, in yellow; marine shales, 

in various shades of gray; estuarine and fluvial sandstones in 

orange; interbedded sandstone and shale in tan. Location shown 

in figure 2.
Thermal Maturity Maps 7

The upper sandy member ranges in thickness from about 

1,800 ft in the western part of the basin to about 3,500 ft in 

the southeastern part (Johnson and others, 2007). It consists of 

light to medium gray sandstones and tan and gray shales. Dunleavy and Gilbertson (1986) referred to sandstones in the upper 

part of the member in the northern part of the basin as the “Sussex” and “Shannon” sandstone beds, which, according to them 

were deposited “as a near-shore bar complex along the edge of 

a delta.” Like sandstones in the underlying Frontier Formation, 

many individual sandstones in the upper part of the Cody are 

blanket-like and can be traced over several miles before pinching out into marine shale. The upper sandy member becomes 

less distinct in the southeastern part of the basin where it grades 

laterally into more shaly facies (Finn, 2007b) (fig. 4).

 The Conant Creek tongue of the Cody Shale, informally 

named by Szmajter (1993), trends north-south across the 

central part of the basin, and is separated from the upper sandy 

member by an eastward thinning clastic wedge of marginal 

marine and nonmarine rocks informally referred to as the 

Alkali Butte member of the Mesaverde Formation by Hogle 

and Jones (1991) (fig. 4). The Conant Creek tongue is generally 

400 to 900 ft thick, but thins to zero where it grades westward 

into nonmarine rocks of the Mesaverde Formation (fig. 4).

The Wallace Creek Tongue of the Cody Shale occupies 

the eastern and southeastern parts of the Wind River Basin and 

is stratigraphically higher and younger than the Conant Creek 

tongue to the west. It is a westward-thinning tongue of marine 

shale that separates the Fales Sandstone Member at the base of 

the Mesaverde Formation from the upper part of the formation 

(Barwin, 1961) (fig. 4). The Wallace Creek Tongue is nearly 

500 ft thick in the southeastern corner of the basin and thins to 

zero in the northern part of the Coalbank Hills, where it grades 

into the main part of the Mesaverde Formation (fig. 4).

Thermal Maturity Maps

Maps showing the levels of thermal maturity based on 

vitrinite reflectance (Ro) for Cretaceous marine shales in the 

Wind River Basin are shown as three separate maps on the map 

sheet. They were constructed using Ro data published by Johnson and others (1991), Barker and Crysdale (1993), Nuccio and 

others (1993, 1996), Pawlewicz (1993), Finn and others (2006), 

and Pawlewicz and Finn (2013), from samples collected from 

wells drilled for oil and gas exploration and production, and 

from outcrops. For wells that reported Ro measurements over 

a range of depths, these data were plotted on a log (Ro) versus 

depth plot for each well and a visual best-fit line was drawn 

through the data (for example, see fig. 6). Data points that 

appeared to be anomalously high or low with respect to the 

main trend were disregarded. In some cases, data from closely 

associated wells were combined into a composite log (Ro) 

versus depth plot. For a single well or outcrop location where 

few Ro measurements were available over a short depth range 

or stratigraphic interval, the available data were averaged and 

the calculated Ro was plotted for that location.

The three maps presented on the map sheet were constructed to show the thermal maturity of Upper Cretaceous 

marine shales in the Wind River Basin at: (1) top of the Cody 

Shale, (2) top of the lower shaly member of the Cody Shale 

(Niobrara equivalent), and (3) the top of the Mowry Shale.

• Because the contact between the Cody Shale and the 

overlying Mesaverde Formation rises stratigraphically 

to the east (figs. 3, 4), it was necessary to change the 

contoured interval from west to east across map 1 (top 

of Cody Shale). In the western part of the basin, the 

contours are drawn at the base of the basal sandstone 

member of the Mesaverde Formation. In the central 

part, they are drawn at the top of the Conant Creek 

tongue of the Cody Shale, and in the eastern and southeastern parts they are drawn at the top of the Wallace 

Creek Tongue (figs. 3 and 4; and map 1 on the sheet).

• The Ro map for the top of the lower shaly member (map 

2 on the map sheet) is contoured at the contact between 

the lower shaly member and the overlying sandy 

member in the western and central parts of the basin. 

However, in the eastern and southeastern parts of the 

basin, these subdivisions are less distinct and the contours are drawn at the top of the Niobrara-equivalent 

strata based on well log correlations from the Powder 

River Basin by Merewether and others (1977a, b) (figs. 

3 and 4; and map 2 on the map sheet).

• The Ro map for the Mowry Shale (map 3 on the map 

sheet) is drawn on the Clay Spur Bentonite Bed (fig. 4).

For all three contoured horizons, the maps show gradual 

increases in maturity from the margins of the Wind River Basin 

northward into the deeper parts of the basin, which reflect its 

structural configuration (fig. 2). In each case, Rovalues range 

from less than 0.6 percent along the shallow margins of the 

basin increasing to greater than 3.0 to 4.0 percent in the deeper 

parts along the main basin trough and in the area of the Madden anticline near the northern margin of the basin (maps 1–3 

on the map sheet). These thermal maturity trends show that 

large areas of the basin are thermally mature (Ro> about 0.6 

percent) to overmature (Ro > about 1.35 percent) with respect 

to oil generation based on parameters defined by Peters and 

Cassa (1994). A structural cross section extending from the 

Madden anticline south to the southern margin of the basin 

illustrates the relation between present-day structural configuration of the basin and the levels of thermal maturity (fig. 7). 

The cross section shows that the isoreflectance lines are nearly 

horizontal and cut across present-day structures, indicating that 

the thermal maturation developed mainly after basin formation 

and deformation during the Laramide orogeny and subsequent 

accumulation of basin fill (Bustin and others, 1983; Barker and 

Crysdale, 1993; Nuccio and others, 1996). 
8 Maps Showing Thermal Maturity of Upper Cretaceous Marine Shales in the Wind River Basin, Wyoming

0.1 1.0 10

0

5,000

10,000

15,000

20,000

Depth, in feet

Percent Ro

Wallace Creek Tongue

of Cody Shale

Lower shaly member

of Cody Shale

Mowry Shale

Coastal Oil and Gas 3–8–36–86 Bullfrog Unit

sec. 8, T. 36 N., R. 86 W. 

Kmr

Kf

Kcl

Kcu

Kmtc

Kmvf

Kmv

Kml

Kl

Tfw

Tfl

Kcw

?

Figure 6. Log (Ro) versus depth plot for the Coastal Oil and Gas 3-8-36-86 

Bullfrog Unit well. Tfw, Waltman Shale Member of Fort Union Formation; 

Tfl, lower unnamed member of Fort Union Formation; Kl, Lance Formation; 

Kml, Meeteetse Formation and Lewis Shale, undivided; Kmv, Mesaverde 

Formation; Kcw, Wallace Creek Tongue of Cody Shale; Kmvf, Fales Member 

of Mesaverde Formation; Kcu, upper sandy member of Cody Shale; Kcl, lower 

shaly member of Cody Shale; Kf, Frontier Formation; Kmr, Mowry Shale; Kmtc, 

Muddy Sandstone, Thermopolis Shale, and Cloverly Formation, undivided.
?

?

SOUTH 

Muscratanticline

Conant Creek

anticline Castle Gardens Moneta Hills

Madden anticline 

Twdr Twdr

Tfw Tfw

Tfu

Tfu

Tfu

Kl

Kl

Kme

Kme

K

Kmv

Kc

Kf

Kf



shaly member

sandy member

shaly member

sandy

member

Kmtc

Kmtc

Kmr

J–

J–





MADDEN THRUST FAULT

Other wells 

VERTICAL EXAGGERATION X 4

Federal–Wolf 1 Hanagan 1–1 Moneta Hills 1–29 Bighorn 1–5 Victor 1

-15,000-10,000

-5,000

-20,000-25,000

Sea level

5,000

10,000

00

5

5

10 MILES

10 KILOMETERS

0.6

0.8

1.1

2.0

3.0

1.35

4.0

Wind River

Basin





J–

Kmtc

Kf

Kmr

Kc

Kmv

Kme

Kl

Tfu

Twdr

Precambrian crystalline rocks

Paleozoic sedimentary rocks—Undivided

Jurassic to Triassic sedimentary rocks—U

Lower Cretaceous—Muddy Sandstone,

Thermopolis Shale, and Cloverly Form

Upper and Lower Cretaceous—Frontier

Formation and Mowry Shale

Upper Cretaceous—Cody Shale

Upper Cretaceous—Mesaverde Formation

Upper Cretaceous—Meeteetse Formation

Upper Cretaceous—Lance Formation

Paleocene—Fort Union Formation

Tfw Paleocene—Fort Union Formation,

Waltman Shale Member

Lower Eocene—Wind River Formation

Tu Post Lower Eocene rocks

EXPLANATION

0.60 Isoreflectance line (in percent)

Contact—Dashed where inferred Drilling well for hydrocrabon exploration

Fault

WYOMING

Wind River

Basin

Location of cross section

Figure 7. South-north structural cross section across the central part of the Wind River Basin, Wyoming, showing relation between present-day thermal maturity based on vitrinite reflectance. Line of section shown in fig. 2 and on map sheet. The part of the line of section north of the Maddfrom Ray and Keefer (1985). 
10 Maps Showing Thermal Maturity of Upper Cretaceous Marine Shales in the Wind River Basin, Wyoming

Acknowledgments

The manuscript and plates benefited from reviews by 

Dick Keefer, Phil Nelson, Dave Ferderer, and Tom Judkins, 

and their suggestions and comments are greatly appreciated.

References Cited

Barker, C.E., and Crysdale, B.L., 1993, Burial and temperature 

history of gas generation from coaly organic matter in the 

Late Cretaceous Mesaverde Formation and associated rocks 

in the deeper portions of the Wind River Basin, Wyoming, 

in Stroock, Betty, and Andrew, Sam, eds., Jubilee Anniversary 44th Field Conference: Wyoming Geological Association, p. 235–258.

Barwin, J.R., 1961, Stratigraphy of the Mesaverde Formation 

in the southeastern part of the Wind River Basin, Fremont 

and Natrona counties, Wyoming: Laramie, Wyo., Master’s 

thesis, University of Wyoming, 78p.

Burtner, R.L., and Warner, M.A., 1984, Hydrocarbon generation in lower Cretaceous Mowry and Skull Creek Shales 

of the northern Rocky Mountain area, in Woodward, Jane, 

Meissner, F.F, and Clayton, J.L., eds., Hydrocarbon source 

rocks of the greater Rocky Mountain region: Rocky Mountain Association of Geologists Guidebook, p. 449–467.

Bustin, R.M., Cameron, A.R., Grieve, D.A., and Kalkreuth, 

W.D., 1983, Coal petrology, its principles, methods, and 

applications: Geological Association of Canada, Short 

Course Notes, v. 3, 230 p.

Byers, C.W., and Larson, D.W., 1979, Paleoenvironments 

of Mowry Shale (Lower Cretaceous), western and central 

Wyoming: American Association of Petroleum Geologists 

Bulletin, v. 63, no. 3, p. 354–361.

Clayton, J.L., and Swetland, P.J., 1977, Preliminary report—

Petroleum geochemistry of the Denver Basin, in Veal, H.K., 

ed., Exploration frontiers of the central and southern Rockies: Rocky Mountain Association of Geologists, p. 223–233. 

Cobban, W.A., and Kennedy, W.J., 1989, The ammonite 

Metengonoceras Hyatt, 1903, from the Mowry Shale 

(Cretaceous) of Montana and Wyoming: U.S. Geological 

Survey Bulletin 1787–L, 11 p.

Curtis, J.B., 2002, Fractured shale-gas systems: American 

Association of Petroleum Geologists Bulletin, v. 86, no. 11, 

p. 1921–1938.

Davis, H.R., 1986, Amount and type of organic matter in the 

Cretaceous Mowry Shale of Wyoming: U.S. Geological 

Survey Open-File Report 86–412, 17 p.

Davis, H.R., Byers, C.W., and Pratt, L.M., 1989, Depositional 

mechanisms and organic matter in Mowry Shale 

(Cretaceous), Wyoming: American Association of 

etroleum Geologists Bulletin, v. 73, no. 9, p. 1103–1116.

De Bruin, R.H., 1993, Overview of oil and gas geology of 

Wyoming, in Snoke, A.W., Steidtmann, J.R., and Roberts, 

S.M., eds., Geology of Wyoming: Geological Survey of 

Wyoming Memoir no. 5, p. 836–873.

Dickinson, W.R., Klute, M.A., Hayes, M.J., Janecke, S.U., 

Lundin, E.R., McKittrick, M.A., and Olivares, M.D., 

1988, Paleogeographic and paleotectonic setting of 

Laramide sedimentary basins in the central Rocky Mountain 

region: Geological Society of America Bulletin, v. 100, 

p. 1023–1039.

Dunleavy, J.M., and Gilbertson, R.L., 1986, Madden anticline—Growing giant, in Noll, J.H., and Doyle, K.M., eds., 

Rocky Mountain oil and gas fields: Wyoming Geological 

Association, p. 107-157.

Eicher, D.L., 1962, Biostratigraphy of the Thermopolis, 

Muddy, and Shell Creek Formations, in Enyert, R.L., and 

Curry, W.H., III, eds., Symposium on Early Cretaceous 

rocks of Wyoming and adjacent areas: Wyoming Geological 

Association 17th Annual Field Conference guidebook, 

p. 72–93.

Finn, T.M., 2007a, Source rock potential of Upper Cretaceous 

marine shales in the Wind River Basin, Wyoming, in

U.S. Geological Survey Wind River Basin Assessment 

Team, eds., Petroleum Systems and Geologic Assessment 

of Oil and Gas Resources in the Wind River Basin 

Province, Wyoming: U.S. Geological Survey Digital Data 

Series DDS–69–J, chap. 8, 24 p.

Finn, T.M., 2007b, Subsurface stratigraphic cross sections 

of Cretaceous and Lower Tertiary rocks in the Wind River 

Basin, central Wyoming, Wyoming, in U.S. Geological 

Survey Wind River Basin Assessment Team, eds., Petroleum Systems and Geologic Assessment of Oil and Gas 

Resources in the Wind River Basin Province, Wyoming: 

U.S. Geological Survey Digital Data Series DDS–69–J, 

chap. 9, 28 p.

Finn, T.M., 2010, New source rock data for the Thermopolis 

and Mowry Shales in the Wyoming part of the Bighorn 

Basin, in U.S. Geological Survey Bighorn Basin Assessment Team, eds., Petroleum Systems and Geologic Assessment of Oil and Gas in the Bighorn Basin Province, 

Wyoming and Montana: U.S. Geological Survey Digital 

Data Series DDS–69–V, chap. 4, 15 p. 

Finn, T.M., Roberts, L.N.R., and Pawlewicz, M.J., 2006, 

Vitrinite reflectance data for the Wind River Basin, 

central Wyoming: U.S. Geological Survey Open-File 

Report 2006–1015, 4 p.
References Cited 11

Fox, J.E., and Dolton, G.L., 1989, Petroleum geology of the 

Wind River and Bighorn Basins, Wyoming and Montana: 

U.S. Geological Survey Open-File Report 87–450P, 41 p.

Fox, J.E., and Dolton, G.L., 1996, Wind River Basin Province 

(35); in Gautier, D.L., Dolton, G.L., Takahashi, K.I., and 

Varnes, K.L., eds., 1995 National assessment of United 

States oil and gas resources—Results, methodology, and 

supporting data: U.S. Geological Survey Digital Data Series 

DDS–30, release 2.

Hagen, E.S., and Surdam, R.C., 1984, Maturation history 

and thermal evolution of Cretaceous source rocks of the 

Bighorn Basin, Wyoming and Montana, in Woodward, Jane, 

Meissner, F.F., and Clayton, J.L., eds., Hydrocarbon source 

rocks of the greater Rocky Mountain region: Rocky Mountain Association of Geologists Guidebook, p. 321–338.

Hogle, D.G., and Jones, R.W., 1991, Subsurface geology of 

Upper Cretaceous and Lower Tertiary coal-bearing rocks, 

Wind River Basin, Wyoming: The Mountain Geologist, 

v. 28, nos. 2 and 3, p. 13–36.

Johnson, R.C., Barker, C.E., Pawlewicz, M.J., Crysdale, B.L., 

Clark, A.C., and Rice, D.D., 1991, Preliminary results of 

coalbed methane assessment of the Wind River Indian 

Reservation, Wyoming, in Schwochow, S.D., Murray, D.K., 

and Fahy, M.F., eds., Coalbed methane of western North 

America: Rocky Mountain Association of Geologists, 

p. 273–284.

Johnson, R.C., Finn, T.M., Crovelli, R.A., and Balay, R.H., 

1996, An assessment of in-place gas resources in lowpermeability Upper Cretaceous and Lower Tertiary 

sandstone reservoirs, Wind River Basin, Wyoming: 

U.S. Geological Survey Open-File Report 96–264, 67 p.

Johnson, R.C., Finn, T.M., Kirschbaum, M.A., Roberts, S.B., 

Roberts, L.N.R., Cook, Troy, and Taylor, D.J., 2007, The 

Cretaceous-Lower Tertiary Composite Total Petroleum 

System, Wind River Basin, Wyoming, in U.S. Geological 

Survey Wind River Basin Province Assessment Team, eds., 

Petroleum Systems and Geologic Assessment of Oil 

and Gas Resources in the Wind River Basin Province, 

Wyoming: U.S. Geological Survey Digital Data Series 

DDS–69–J, chap. 4, 96 p.

Johnson, R.C., and Rice, D.D., 1993, Variations in composition and origins of gases from coal bed and conventional 

reservoirs, Wind River Basin, Wyoming, in Keefer, W.R., 

Metzger, W.J., and Godwin, L.H., eds., Oil and gas and 

other resources of the Wind River Basin, Wyoming: 

Wyoming Geological Association, Special Symposium, 

p. 319–335.

Kauffman, E.G., 1977, Geological and biological overview—

Western Interior Cretaceous basin, in Kauffman, E.G., ed., 

Cretaceous facies, faunas, and paleoenvironments across 

the Western Interior Basin: The Mountain Geologist, v. 14, 

nos. 3 and 4, p. 75–99.

Keefer, W.R., 1969, Geology of petroleum in the Wind River 

Basin, central Wyoming: American Association of Petroleum Geologists Bulletin, v. 53, no. 9, p. 1839–1865.

Keefer, W.R., 1972, Frontier, Cody, and Mesaverde 

Formations in the Wind River and southern Bighorn 

Basins, Wyoming: U.S. Geological Survey Professional 

Paper 495–E, 23 p.

Keefer, W.R., and Johnson, R.C., 1997, Stratigraphy and correlation of Cretaceous and Paleocene rocks, west-central 

Wind River Basin, Wyoming, U.S. Geological Survey Oil 

and Gas Investigations Chart OC–146–B.

Keefer, W.R., and Troyer, M.L., 1964, Geology of the Shotgun 

Butte area, Fremont County, Wyoming: U.S. Geological 

Survey Bulletin 1157, 123 p.

Landon, S.M., Longman, M.W., and Luneau, B.A., 2001, 

Hydrocarbon source rock potential of the Upper Cretaceous 

Niobrara Formation, Western Interior Seaway of the Rocky 

Mountain region: The Mountain Geologist, v. 38, no. 1, 

p. 1–18.

Longman, M.W., Luneau, B.A., and Landon, S.M., 1998, 

Nature and distribution of Niobrara lithologies in the Cretaceous Western Interior Seaway of the Rocky Mountain 

Region: The Mountain Geologist, v. 35, no. 4, p. 137–170.

Meissner, F.F., Woodward, Jane, and Clayton, J.L., 1984, 

Stratigraphic relationships and distribution of source rocks 

in the greater Rocky Mountain region, in Woodward, Jane, 

Meissner, F.F., and Clayton, J.L., eds., Hydrocarbon source 

rocks of the greater Rocky Mountain region: Rocky 

Mountain Association of Geologists Guidebook, p. 1–34.

Merewether, E.A., 1996, Stratigraphy and tectonic implications of Upper Cretaceous rocks in the Powder River 

Basin, northeastern Wyoming and southeastern Montana: 

U.S. Geological Survey Bulletin 1917–T, 92 p.

Merewether, E.A., and Claypool, G.E., 1980, Organic composition of some Upper Cretaceous shale, Powder River Basin, 

Wyoming: American Association of Petroleum Geologists 

Bulletin, v. 64, no. 4, p. 488–500.

Merewether, E.A., Cobban, W.A., Matson, R.M., and Magathan, W.J., 1977a, Stratigraphic diagrams with electric logs 

of Upper Cretaceous rocks, Powder River Basin, Natrona, 

Converse, and Weston Counties, Wyoming: U.S. Geological 

Survey Oil and Gas Investigations Map OC–74.
12 Maps Showing Thermal Maturity of Upper Cretaceous Marine Shales in the Wind River Basin, Wyoming

Merewether, E.A., Cobban, W.A., Matson, R.M., and Magathan, W.J., 1977b, Stratigraphic diagrams with electric logs 

of Upper Cretaceous rocks, Powder River Basin, Natrona, 

Converse, and Niobrara counties, Wyoming: U.S. Geological Survey Oil and Gas Investigations Map OC–75.

Merewether, E.A., Dolson, J.C., Hanson, W.B., Keefer, W.R., 

Law, B.E., Mueller, R.E., Ryer, T.A., Smith, A.C., Stilwell, 

D.P., and Wheeler, D.M., 1997, Cretaceous stratigraphy in 

a northeast-trending transect, northern Utah to south-central 

South Dakota: U.S. Geological Survey Geologic Investigations Map I–2609.

Milici, R.C., 1993, Autogenic gas (self sourced) from shales—

An example from the Appalachian Basin, in Howell, D.G., 

ed., The future of energy gases: U.S. Geological Survey 

Professional Paper 1570, p. 253–278.

Momper, J.A., and Williams, J.A., 1984, Geochemical exploration in the Powder River Basin, in Demaison, Gerard, 

and Murris, R.J., eds., Petroleum geochemistry and basin 

evaluation: American Association of Petroleum Geologists 

Memoir 35, p. 181–191.

Nixon, R.P., 1973, Oil source beds in Cretaceous Mowry 

Shale of northwestern interior United States: American 

Association of Petroleum Geologists Bulletin, v. 57, no. 1, 

p. 136–161.

Nuccio, V.F., 1990a, Burial, thermal, and petroleum generation 

history of the Upper Cretaceous Steele Member of the Cody 

Shale (Shannon Sandstone Bed horizon), Powder River 

Basin, Wyoming: U.S. Geological Survey Bulletin 1917–A, 

17 p.

Nuccio, V.F., 1990b, Determination of source-rock thermal 

maturity by direct measurements and predictive modelingapplication to Upper Cretaceous Cody Shale, Powder River 

Basin, Wyoming, in Nuccio, V.F., and Barker, C.E., and 

Dyson, S.J., eds., Applications of thermal maturity studies 

to energy exploration: Rocky Mountain Section Society of 

Economic Paleontologists and Mineralogists, p. 167–175.

Nuccio, V.F., Finn, T.M., and Johnson, R.C., 1996, Thermal 

maturity data for the assessment of gas resources in the 

Wind River Basin, Wyoming: U.S. Geological Survey 

Open-File Report 96v064, 57 p.

Nuccio, V.F., Finn, T.M., and Pawlewicz, M.J., 1993, Surface 

vitrinite reflectance study of the Wind River Basin, central 

Wyoming, in Keefer, W.R., Metzger, W.J., and Godwin, 

L.H., eds., Oil and gas and other resources of the Wind 

River Basin: Wyoming Geological Association Special 

Symposium, p. 307–317.

Obradovich, J.D., 1993, A Cretaceous time scale, in Caldwell, 

W.G.E., and Kauffman, E.G., eds., Evolution of the Western 

Interior Basin: Geological Association of Canada Special 

Paper 39, p. 379–396.

Obradovich, J.D., Cobban, W.A., Merewether, E.A., and 

Weimer, R.J., 1996, A time framework for the late Albanian 

and early Cenomanian strata of northern Wyoming and 

Montana: Geological Society of America Abstracts with 

Programs, 1996 Annual Meeting, Denver, Colo., v. 28, 

no. 7, p. A–66. 

Passey, Q.R., Bohacs, K.M., Esch, W.L., Klimentidis, Robert, 

and Sinha, Somnath, 2010, From oil-prone source rock to 

gas-producing shale reservoir—Geologic and petrophysical characterization of unconventional shale-gas reservoirs: 

Society of Petroleum Engineers Paper 131350, 29 p.

Pawlewicz, M.J., 1993, Vitrinite reflectance and geothermal gradients in the Wind River Basin, in Keefer, W.R., 

Metzger, W.J., and Godwin, L.H., eds., Oil and gas and 

other resources of the Wind River Basin: Wyoming Geological Association Special Symposium, p. 295-306.

Pawlewicz, M.J., and Finn, T.M., 2013, New vitrinite 

reflectance data for the Wind River Basin, Wyoming: 

U.S. Geological Survey Open-File Report 2013–1002, 11 p.

Peters, K.E., and Cassa, M.R., 1994, Applied source rock 

geochemistry, in Magoon, L.B., and Dow, W.G., eds., The 

petroleum system—From source to trap: American Association of Petroleum Geologists Memoir 60, p. 93–120.

Ray, R.R., and Keefer, W.R., 1985, Wind River Basin, central 

Wyoming, in Gries, R.R., and Dyer, R.C., eds., Seismic 

Exploration of the Rocky Mountain Region: Rocky Mountain Association of Geologists, and Denver Geophysical 

Society, p. 201–212.

Roberts, L.N.R., Finn, T.M., Lewan, M.D., and Kirschbaum, 

M.A., 2007, Burial history, thermal maturity, and oil and 

gas generation history of petroleum systems in the Wind 

River Basin province, central Wyoming, in U.S. Geological 

Survey Wind River Basin Assessment Team, eds., Petroleum Systems and Geologic Assessment of Oil and Gas 

Resources in the Wind River Basin Province, Wyoming: 

U.S. Geological Survey Digital Data Series DDS–69–J, 

chap. 6, 26 p.

Roberts, L.N.R., Finn, T.M., Lewan, M.D., and Kirschbaum, 

M.A., 2008, Burial history, thermal history, and oil and gas 

generation history of source rocks in the Bighorn Basin, 

Wyoming and Montana: U.S. Geological Survey Scientific 

Investigations Report 2008–5037, 28 p.

Roberts, L.N.R., Lewan, M.N., and Finn, T.M., 2004, Timing of oil and gas generation of petroleum systems in the 

Southwestern Wyoming Province: The Mountain Geologist, 

v. 41, no. 3, p. 87–118.

Schelling, D.D., and Wavrek, D.A., 1999, Structural geology 

and petroleum systems of the Madden field, Wind River 

Basin, Wyoming: American Association of Petroleum 

Geologists, v. 83, no. 13 (supplement).
References Cited 13

Schelling, D.D., and Wavrek, D.A., 2001, Structural geology 

and petroleum systems of the northwestern Wind River 

Basin, Wyoming: American Association of Petroleum 

Geologists, v. 85, no. 13 (supplement).

Schrayer, G.J., and Zarrella, W.M., 1963, Organic geochemistry of shale—I Distribution of organic matter in the 

siliceous Mowry Shale of Wyoming: Geochimica et 

Cosmochimica Acta, v. 27, no. 10, p. 1033–1046.

Schrayer, G.J., and Zarrella, W.M., 1966, Organic geochemistry of shale—II Distribution of extractable organic matter 

in the siliceous Mowry Shale of Wyoming: Geochimica et 

Cosmochimica Acta, v. 30, no. 4, p. 415–434.

Schrayer, G.J., and Zarrella, W.M., 1968, Organic carbon 

in Mowry Formation and its relation to the occurrence of 

petroleum in Lower Cretaceous reservoir rocks, in Wulf, 

G.R., ed., Black Hills area South Dakota, Montana, 

Wyoming: Wyoming Geological Association, 20th Field 

Conference Guidebook, p. 35–39.

Sonnenberg, S.A., 2011, The Niobrara Petroleum System—

A new resource play in the Rocky Mountain Region, in

Estes-Jackson, J.E., and Anderson, D.S., eds., Revisiting 

and revitalizing the Niobrara in the central Rockies: Rocky 

Mountain Association of Geologists, p. 13-32.

Sterling, R., Silverman, M., and Stewart, G., 2009, The 

Mowry Shale, review of potential in the Bighorn Basin, 

in Unconventional reservoirs—Oil and gas shales and 

CBM, Sept. 14, 2009, Denver, Colo: Denver, Colo., Rocky 

Mountain Association of Geologists and PTTC (Petroleum 

Technology Transfer Council) fall symposium., 1 p.

Szmajter, R.J., 1993, Subsurface stratigraphic cross section 

of Lower and Upper Cretaceous rocks in the south-central 

Wind River Basin, Wyoming, in Keefer, W.R., Metzger, 

W.J., and Godwin, L.H., eds., Oil and gas and other 

resources of the Wind River Basin, Wyoming: Wyoming 

Geological Association, Special Symposium, p. 87-90.

Thompson, R.M., and White, V.L., 1954, Geology of the 

Riverton area, central Wyoming: U.S. Geological Survey 

Oil and Gas Investigations Map OM–127.

Yenne, K.A., and Pipiringos, G.N., 1954, The Cody Shale and 

younger Cretaceous and Paleocene rocks in the Wind River 

Basin, Fremont County, Wyoming: U.S. Geological Survey 

Oil and Gas Investigations Chart OC–49.

Publishing support provided by: 

Denver Publishing Service Center

For more information concerning this publication, contact: 

Center Director, USGS Central Energy Resources Science Center 

Box 25046, Mail Stop 939 

Denver, CO 80225 

(303) 236-1647 

Or visit the Central Energy Resources Science Center Web site at: 

http://energy.usgs.gov/ 
Finn and Pawlewicz—Maps Showing Thermal Maturity of Upper Cretaceous Marine Shales, Wind River Basin, WY—Scientific Investigations Map 3266

ISSN 2329-132X (online)

http://dx.doi.org/10.3133/sim3266