Stratigraphic Cross Sections of the Niobrara Interval of the Cody Shale and Associated Rocks in the Wind River Basin, Central Wyoming

Pamphlet to accompany Scientific Investigations Map 3370

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

Stratigraphic Cross Sections of the Niobrara Interval of the Cody Shale and Associated Rocks in the Wind River Basin, Central Wyoming

By Thomas M. Finn

Pamphlet to accompany Scientific Investigations Map 3370

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, Director

U.S. Geological Survey, Reston, Virginia: 2017

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Suggested citation: Finn, T.M., 2017, Stratigraphic cross sections of the Niobrara interval of the Cody Shale and associated rocks in the Wind River Basin, central Wyoming: U.S. Geological Survey Scientific Investigations Map 3370, 19 p., 1 sheet, https://doi.org/10.3133/sim3370.

ISSN 2329-132X (online) iii

Contents

Introduction...... 1 Depositional setting...... 6 Stratigraphy...... 6 Cody Shale...... 6 Niobrara Interval...... 14 Sage Breaks Interval...... 14 Acknowledgments...... 14 References Cited...... 17

Sheet

1. Detailed cross sections of Niobrara equivalent strata in the Wind River Basin, Wyoming...... link

Figures

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...... 2 2. Index map of the Wind River Basin Province in central Wyoming showing major structural and physiographic features discussed in the text...... 3 3. Index map of the Wind River Basin showing the cross section lines presented on map sheet...... 4 4. Type log of Lower and lowermost Upper Cretaceous rocks in the southeastern part of the Wind River Basin...... 5 5. Map showing approximate extent of the Western Interior Seaway in North America during late Coniacian (Scaphites depressus Zone)...... 7 6. Regional east-west stratigraphic cross section of Cretaceous rocks in the Wind River Basin...... 8 7. Paleogeographic reconstruction of the Rocky Mountain region during late Coniacian (Scaphites depressus Zone) time showing major depositional trends. Wind River Basin Province outlined in red...... 9 8. Correlation chart showing stratigraphic relations of mid-Cretaceous rocks in the Wind River Basin and correlation with equivalent rocks at various localities in the Powder River Basin and Denver Basin...... 10 9. Isopach map of the Cody Shale...... 11 10. Isopach map of the lower shaly member of the Cody Shale...... 12 11. Isopach map of the upper sandy member of the Cody Shale...... 13 12. Isopach map of the Niobrara equivalent interval in the lower part of the Cody Shale...... 15 13. Isopach map of the Sage Breaks equivalent interval in the lower part of the Cody Shale...... 16 iv

Conversion Factors

U.S. customary units to International System of Units Multiply By To obtain Length inch (in.) 25.4 millimeter (mm) foot (ft) 0.3048 meter (m) mile (mi) 1.609 kilometer (km) Area square mile (mi2) 2.590 square kilometer (km2)

Datum Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83). Altitude, as used in this report, refers to distance above sea level. Stratigraphic Cross Sections of the Niobrara Interval of the Cody Shale and Associated Rocks in the Wind River Basin, Central Wyoming

By Thomas M. Finn

Introduction Cody Shale in the Wind River Basin in central Wyoming. The primary purpose of the cross sections is to show the The Wind River Basin is one of many structural and sedi- stratigraphic relationship of the Niobrara equivalent strata and mentary basins that formed in the Rocky Mountain foreland associated rocks in the lower part of the Cody Shale in the during the Laramide orogeny. The basin is nearly 200 miles Wind River Basin. (mi) long, 70 mi wide, and encompasses about 7,400 square Two cross sections were constructed using borehole geo- miles (mi2) in central Wyoming (fig. 1). The basin is bounded physical logs from 37 wells drilled for oil and gas exploration by the Washakie Range, Owl Creek uplift, and southern Big- and production, and one surface section measured by Keefer horn Mountains on the north, the Casper arch on the east, the and Troyer (1964) along East Sheep Creek near Shotgun Butte Granite Mountains on the south, and Wind River Range on the in the northwestern part of the basin (figs. 2, 3, and map sheet). west (fig. 2). Both lines originate at the East Sheep Creek surface section The first commercial oil well completed in Wyoming and end near Clarkson Hill in the extreme southeastern part of was drilled near an oil seep in 1884 at Dallas dome near the basin. The northern line extends from the Shotgun Butte the southwestern edge of the Wind River Basin (Biggs and area east along the northern margin of the basin to the Madden Espach, 1960). Since then many important conventional oil anticline, then southeast to Tepee Flats and Hells Half Acre, and gas fields producing from reservoirs ranging in age from then along the southwest margin of the Casper arch to Clarkson Mississippian through Tertiary have been discovered in that Hill (figs. 2, 3, and map sheet). The southern line extends from basin (Keefer, 1969; Fox and Dolton, 1989, 1996; De Bruin, the Shotgun Butte area south then east to Alkali Butte and 1993). In addition, an extensive unconventional overpressured along the southern margin of the basin to the Coalbank Hills, basin-centered gas accumulation has been identified in then southeast along the northeast flank of the Rattlesnake Hills Cretaceous and Tertiary strata in the deeper parts of the basin to Clarkson Hill (figs. 2, 3, and map sheet). The stratigraphic (Spencer, 1987; Johnson and others, 1996; Jiao and Surdam, interval extends from the upper part of the Frontier Formation 1997; Surdam and others, 1997; Johnson and others, 2007). to the middle part of the Cody Shale. The datum is the base It has long been suggested that various Upper Cretaceous of the “chalk kick” marker bed, a distinctive resistivity peak marine shales, including the Cody Shale, are the principal or zone in the lower part of the Cody Shale. This datum was hydrocarbon source rocks for many of these accumulations selected because it is easily identified on most well logs and is (see, for example: Keefer, 1969; Meissner and others, 1984; present throughout the basin (fig. 4, map sheet). Fox and Dolton, 1989, 1996; Johnson and Rice, 1993; Nuccio A gamma ray and (or) spontaneous potential (SP) log was and others, 1996; Schelling and Wavrek, 1999, 2001; and used in combination with a resistivity log to identify and cor- Finn, 2007a). With recent advances and success in horizontal relate units. Gamma ray and SP logs are typically used to dif- drilling and multistage fracture stimulation, there has been ferentiate between sandstone and shale; however, in the Wind an increase in exploration and completion of wells in these River Basin the spontaneous potential response is subdued marine shales in other Rocky Mountain Laramide basins that in some sandstone intervals showing little curve deflection. were traditionally thought of only as hydrocarbon source In areas of greater drilling density, logs from wells located rocks (Colorado Geological Survey, 2011; Sonnenberg, 2011; between control wells on the cross sections were used to aid in Williams and Lyle, 2011). making correlations. Marine molluscan index fossils collected The stratigraphic cross sections presented in this report from nearby outcrop sections were projected into the subsur- were constructed as part of a project carried out by the U.S. face to help determine the relative ages of the strata and aid in Geological Survey (USGS) to characterize and evaluate correlation. The sources for the fossil data are from Cobban the undiscovered continuous (unconventional) oil and gas (1951, 1969), Yenne and Pipiringos (1954), Keefer and resources of the Niobrara interval of the Upper Cretaceous Troyer (1964), Keefer (1972), Landman and Cobban (2007), 2 Stratigraphic Cross Sections of the Niobrara Interval of the Cody Shale and Associated Rocks, Wind River Basin, WY

112° 110° 108° 106° 104°

DAKOTA NORTH Bull 46° Mountains Miles Crazy Reed Point Basin City

Mountains syncline arch Basin Bridgeruplift

Powder Nye-Bowler Bighorn

lineament DAKOTA SOUTH Beartooth Absaroka uplift Pryor Mountains MONTANA Bighorn WYOMING volcanic uplift River Black Hills uplift

44° Basin field

uplift Teton Washakie Range Basin Casper arch

belt Owl Creek uplift Wind Wind River

Basin NEBRASKA River Granite Mountains orogenic uplift uplift Shirley Basin 42° IDAHO Hartville uplift Rawlins UTAH uplift Hanna Greater Green Basin Sierra Madre River Basin uplift Medicine

LaramieBasin

Cordilleran

Bow Denver Park uplift uplift Uinta Axial Range Basin North and Middle uplift Park Basins 40° uplift Front Uinta Basin Basin White Piceance River Range uplift Basin Sawatch uplift Uplift

San RafaelSwell Douglas Creek arch

Uncompahgre Gunnison South Park uplift Basin uplift

38° San Sangre Juan de Cristo Raton San Juan volcanic uplift rift field uplift Basin UTAH COLORADO ARIZONA NEW MEXICO San Juan EXPLANATION Basin Grande

Nacimiento uplift 36° Thrust or reverse fault— (Neogene) uplift Dashed where approximate Zuni uplift 0 50 100 MILES 0 50 100 KILOMETERS de Cristo

Rio

Sangre

Base modified from U.S. Geological Survey digital, 2,000,000 Albers Equal-Area Conic projection Standard parallels 29°30’ and 45°30’, central meridian –108° Latitude of origin 23° North American Datum of 1983 (NAD83)

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).

\\IGSKAHCMVSFS002\Pubs_Common\Jeff\den16_cmrm00_0048_sim_finn\report_figures\figure_01.ai Introduction 3 T. T. T. T. N. N. 40 45 N. N. 30 35 Tepee Flats Tepee Madden anticline 10 11 R. 80 W. R 80 W Province

106°30' 5,000 5,000 1 Wind Basin River

WYOMING arch Lander East Sheep Hells Half Acre 5,000

S.L. 7 8 9

Casper

107° S.L. R. 85 W. R 85 W 9 -5,000 S.L. 5,000 Conant Creek anticline Alkali Butte anticline Dallas dome 5,000 10 2 4 5 6

S.L. Mountains Bighorn Granite 3 Mountains 30' Clarkson Hill Rattlesnake Hills Coalbank Hills Major structural and physiographic features 1 2 3

S.L. R. 90 W. R 90 W 11

-15,000

-15,000 5,000

-10,000 S.L.

-5,000

S.L.

108° Mountains 4 T N T 35 N 40 T 5 N T 1 T 1 Type log, Exxon Corp. Poison Type Springs Unit 1 S N 5 Chalk Kick contour— Contour interval 5,000 feet. S.L. is sea level R. 95 W. R 95 W R 95 W R 5 E R 5 E

5,000 EXPLANATION

Creek -15,000 30'

-10,000 6 8 -5,000 Owl

S.L. 7 High-angle fault Anticline— Arrowhead shows direction of plunge Syncline R 1 E 5,000 R 1 E R. 100 W. R 100 W R 100 W R 1 W R 1 W Range 109° S.L. 5,000 Range T 1 S R 5 W ? R 5 W

Range River 40 MILES T. N. 45 R. 105 W. Wind River Basin Province boundary Thrust fault— Sawteeth on upper plate Normal fault— Ball and bar on downthrown block T 5 N R 105 W T 1 N T N 30 R 105 W T N T 30' N 40 35 ? 30

Absaroka Wind 40 KILOMETERS

Washakie 20 30 108° 20 10 110° R. 110 W. Index map of the Wind River Basin Province in central Wyoming showing major structural and physiographic features discussed in the text: (1) Clarkson Hill, Index map of the Wind River Basin Province in central Wyoming 10 R 110 W

Tertiary volcanic rock Tertiary Frontier Formation outcrop Precambrian rock Wind River Basin Province 0 0 Base from Bureau of Land Management digital data, 2016 Lambert Conformal Conic projection Standard parallels 33° and 45° Central meridian – Latitude of origin 39° North American Datum of 1983 (NAD83)

43° Figure 2. (8) East Sheep Creek/Shotgun Butte, (9) Hells (2) Rattlesnake Hills, (3) Coalbank (4) Conant Creek anticline, (5) Alkali Butte (6) Dallas dome, (7) Lander, Flats gas field, and (11) Madden anticline. Structure contours are drawn at base of the “chalk kick” marker bed. Contour interval is 5,000 feet. Half Acre, (10) Teepee S.L., sea level.

43°30' 42°30' \\IGSKAHCMVSFS002\Pubs_Common\Jeff\den16_cmrm00_0048_sim_finn\report_figures\figure_02.ai 4 Stratigraphic Cross Sections of the Niobrara Interval of the Cody Shale and Associated Rocks, Wind River Basin, WY T. T. T. T. N. N. 40 45 N. N. 30 35 R. 80 W. R 80 W Province 106°30' Wind Basin River

WYOMING arch

Casper 107° R. 85 W.

R 85 W

Mountains Bighorn Granite Mountains 30'

line R. 90 W.

R 90 W line

108° Mountains

North Wind River Basin Province boundary control point Well East Sheep Creek surface section T N T 35 N 40 T 5 N T 1 T 1 S N R. 95 W. R 95 W R 95 W R 5 E R 5 E EXPLANATION

Creek

30' South

Owl R 1 E R 1 E R. 100 W. Cody Shale outcrop Precambrian rock Wind River Basin Province R 100 W R 100 W R 1 W R 1 W Range 109° T 1 S R 5 W R 5 W

Range River 40 MILES T N 45 R. 105 W. 108° T 5 R 105 W N T 1 N R 105 W T N 30' 40 T N 35 30 T N 30 Wind 40 KILOMETERS

Washakie 20 30 20 Index map of the Wind River Basin showing cross section lines presented on sheet. 10 110°

R. 110 W. 10 R 110 W 0 0 Base from Bureau of Land Management digital data, 2016 Lambert Conformal Conic projection Standard parallels 33° and 45°, Central meridian – Latitude of origin 39° North American Datum of 1983 (NAD83) Figure 3.

43°

43°30' 42°30' \\IGSKAHCMVSFS002\Pubs_Common\Jeff\den16_cmrm00_0048_sim_finn\report_figures\figure_03.ai Introduction 5

Exxon Corporation Poison Springs Unit 1 section 33, T. 32 N., R. 83 W. EXPLANATION GR Res. Interbedded marine sandstone Upper sandy and shale member Marine and marginal marine sandstone and siltstone 10,000 (part) Marine shale

Calcareous marine shale and marl Siliceous marine shale

Estuarine and fluvial sandstone 10,500 Sandstone and conglomerate of fluvial origin Res. Resistivity GR Gamma ray

11,000 Cody Shale (part) Lower shaly member

11,500 Upper Cretaceous (part)

"chalk kick Niobrara Formation equivalent marker" Sage Breaks equivalent 12,000

Frontier Formation 12,500

Clay Spur Bentonite Upper siliceous Mowry part Shale ? 13,000 lower part Muddy Sandstone Thermopolis Shale Lower Cloverly Formation Cretaceous

Figure 4. Type log of Lower and lowermost Upper Cretaceous rocks in the southeastern part of the Wind River Basin. GR, gamma ray log; Res., resistivity log. Location shown in figure 2.

\\IGSKAHCMVSFS002\Pubs_Common\Jeff\den16_cmrm00_0048_sim_finn\report_figures\figure_04.ai 6 Stratigraphic Cross Sections of the Niobrara Interval of the Cody Shale and Associated Rocks, Wind River Basin, WY

Merewether and Cobban (2007), and from files at the USGS Stratigraphy fossil collection in Denver, Colorado (K.C. McKinney, USGS, written commun., 2015). For both sections the horizontal scale Figure 8 is a correlation diagram showing the strati- is about 1 in=5.75 mi and the vertical scale is about 1 in=500 graphic nomenclature for the Cody Shale and associated ft (map sheet). rocks in the Wind River Basin and correlative units at various localities in the Powder River Basin and Denver Basin to the east and southeast, respectively. The Wind River Basin Depositional setting nomenclature is modified from Keefer (1972), and Finn (2007b), the western Powder River Basin nomenclature is During much of Late Cretaceous time, the part of Wyo- modified from Merewether (1996), the northwest Black Hills ming that is now the Wind River Basin was located near the and Pueblo, Colo. (Denver Basin) nomenclature is modi- west edge of the Rocky Mountain foreland basin, an elongate fied from Merewether and others (2011). The stratigraphic north-south structural depression that developed to the east of relationships and nomenclature for the Wind River Basin are the tectonically active Western Cordilleran highlands prior to also illustrated on the regional stratigraphic cross section in the Laramide orogeny (figs. 1 and 5). Throughout much of its figure 6. history, the foreland basin was flooded by a broad epiconti- nental sea, referred to as the Western Interior Seaway (WIS) Cody Shale that developed in response to foreland basin subsidence and eustatic sea-level rise (Steidtmann, 1993). At its maximum The Cody Shale consists of shales, calcareous shales, extent, the WIS extended for more than 3,000 mi from the marls, bentonites, siltstones, and sandstones, with the amount Arctic Ocean to the Gulf of Mexico (fig. 5) (Kauffman, of sandstone and siltstone increasing in the upper part (Keefer, 1977). Erosion of the Western Cordilleran highlands supplied 1972). The main body of the Cody Shale was deposited during sediment to the basin by eastward-flowing streams; whereas, a second-order transgressive-regressive cycle referred to as the eastern shore of the WIS was part of the stable craton the “Niobrara Cyclothem” by Kauffman (1977), and ranges that was topographically low and supplied little sediment in age from latest Turonian to early Campanian. The upper- (Molenaar and Rice, 1988). During much of Late Cretaceous most Cody, of middle Campanian age, was deposited during time, sediments accumulated in or adjacent to the WIS as a subsequent transgressive-regressive cycle that Kauffman the western shoreline repeatedly advanced and retreated (1977) referred to as the Claggett cycle (fig. 8). The lower and across the western part of the basin resulting in a complex upper contacts of the Cody Shale are conformable and inter- pattern of intertonguing marine and nonmarine deposits finger extensively with the underlying Frontier and overlying (fig. 6). Marginal marine and nonmarine deposits are repre- Mesaverde Formations (fig. 6). sented by eastward-thinning wedges of marginal marine and The Cody Shale is about 3,500 feet (ft) thick in the north- nonmarine sandstone, siltstone, shale, carbonaceous shale, western part of the basin increasing to more than 5,500 ft in the and coal. The marine deposits are represented by westward- eastern part (fig. 9). The eastward thickening is due to the east- thinning tongues of marine shale, siltstone, and marine ward stratigraphic rise and intertonguing of the contact between sandstone (fig. 6). The marine sediments were deposited the Cody Shale and the overlying Mesaverde Formation, and during widespread marine transgressions creating highstand the west to northwest backstepping nature of the Frontier/Cody conditions as the seaway deepened, limiting clastic input, contact (fig. 6). Four members are generally recognized, in and at times forming anoxic bottom conditions favorable for ascending order: (1) the lower shaly member (Thompson and the preservation of organic matter (Gries and others, 1992). White, 1954; Yenne and Pipiringos, 1954; Keefer and Troyer, In addition, these transgressions produced two widespread 1964), (2) the upper sandy member (Thompson and White, episodes of carbonate deposition in the WIS: the first resulted 1954; Yenne and Pipiringos, 1954; Keefer and Troyer, 1964), in the deposition of the Upper Cretaceous Greenhorn Forma- (3) the informally named “Conant Creek tongue” (Szmajter, tion, and the second resulted in the deposition of the Upper 1993), and (4) the Wallace Creek Tongue (Barwin, 1961) Cretaceous Niobrara Formation (Longman and others, 1998; (figs. 6 and 8). The age of the Cody ranges from latest Turonian Sonnenberg, 2011). The Niobrara interval is characterized to middle Campanian (Keefer, 1972). by deposition of chalks and marls composed of foraminifers The unnamed lower shaly member, which is in part and coccolith debris that accumulated in the sediment-starved equivalent to the Niobrara Formation (or Member) in the eastern part of the seaway (Longman and others, 1998; Powder River Basin to the east (figs. 6, 8, and map sheet), Sonnenberg, 2011). The chalks grade westward into more reaches a maximum thickness greater than 3,500 ft in the siliciclastic beds that were derived from the eroding highlands southeastern part of the basin and thins to the northwest to to the west, diluting the carbonate sediments (Longman and about 1,100 ft (fig. 10). It is composed of gray to black shale, others, 1998; Sonnenberg, 2011) (fig. 7). In the Wind River calcareous shale, marl, and bentonite, with minor amounts Basin, the Niobrara equivalent rocks are represented by of siltstone and sandstone that were deposited in an offshore shales, calcareous shales, marls, siltstones, and sandstones in marine environment. The lower shaly member ranges in age the lower shaly member of the Cody Shale (fig. 6). from latest Turonian to middle Campanian. Stratigraphy 7

ARCTIC OCEAN

GREENLAND ALASKA

CANADA

WESTERN Study W area E S

T

E

R

N

I N CORDILLERA T

E

R

I

O R UNITED STATES

S

E

A

W

A

Y PACIFIC OCEAN ATLANTIC OCEAN

MEXICO

GULF OF MEXICO

Figure 5. Map showing approximate extent of the Western Interior Seaway in North America during late Coniacian (Scaphites depressus Zone). Modified from Cobban and others (2005).

The upper sandy member is generally around 2,000 ft the “Sussex” and “Shannon” sandstone beds, which, according thick in the western part of the basin and increases to greater to them (p. 115) were deposited “as a near-shore bar complex than 3,500 ft in the south-central and east-central parts of the along the edge of a delta.” Like sandstones in the underlying basin (fig. 11). It thins to less than 1,000 ft in the southeastern Frontier Formation, many individual sandstones in the upper part of the basin where it grades into the lower shaly member part of the Cody are continuous for tens of miles before pinch- (figs. 6, 11, and map sheet). The upper sandy member consists ing out into marine shale. The upper sandy member becomes \\IGSKAHCMVSFS002\Pubs_Common\Jeff\den16_cmrm00_0048_sim_finn\report_figures\figure_05.aiof light to medium gray sandstones and tan and gray shales. less distinct in the southeastern part of the basin, where it Dunleavy and Gilbertson (1986) referred to sandstones in the grades laterally into more shaly facies (fig. 6, and map sheet) upper part of the member in the northern part of the basin as (Finn, 2007b).

8 Stratigraphic Cross Sections of the Niobrara Interval of the Cody Shale and Associated Rocks, Wind River Basin, WY

(part) Upper Cretaceous Upper Lower ?? SOUTHEAST Cretaceous SOUTHEAST NORTHWEST Baculites eliasi Baculites eliasi Baculites obtusus Wind River Basin Province Scaphites corvensis Baculites perplexus LOCATION OF CROSS SECTION Cross Baculites clinolobatus section “Niobrara equivalent” Inoceramus subcompressus Frontier Formation Baculites eliasi Hills Wallace Creek Tongue Wallace Parkman Sandstone Member Rattlesnake Upper sandy member Lewis Shale, upper tongue Muddy Sandstone Lower shaly member Baculites sp. (smooth) Baculites gilberti Plesiacanthoceras wyomingense Unconformity Approximate position of important guide fossil Marine shale, calcareous shale, sandy silty shale, and marlstone Undifferentiated Tertiary rock Undifferentiated Jurassic rock Baculites asperiformis eliasi Baculites Fales Sandstone Member Inoceramus erectus Lewis Shale, lower tongue Hills Coalbank Lance Formation (part) Meeteetse Formation Mowry Shale Unnamed middle member Baculites obtusus Baculites mclearni Baculites perplexus Baculites yokoyamai

e

n

o “Sage Breaks equivalent”

z “Sussex sands”

Thermopolis Shale Thermopolis

I

s Castle i Gardens p Siliceous marine shale in the upper part of the Mowry Shale Laterally persistent zone within the Cody Shale showing higher gamma-ray intensity Interbedded sandstone and shale, marine e Marine, marginal marine or coastal sandstone or siltstone Marine shale

r “Shannon sands” c

o

p

p

i

h

s "chalk kick"

e

t EXPLANATION i Conant Creek tongue

h

p sp. (smooth)

a

c

S

f

o

e

s Scaphites depressus Scaphites preventricocus Scaphites hippocrepis (late form) Scaphites hippocrepis Scaphites depressus Baculites sp. (weak flank ribs) Baculites I Scaphites hippocrepis

a

b

e

t Tertiary a

m i

x

o r

p Alkali Butte member p a Butte Alkali Inoceramus deformis Lower shaly member Plesiacanthoceras wyomingense Upper sandy member Lance Formation (part) Muddy Sandstone Predominantly fluvial sandstone Estuarine and fluvial sandstone Sandstone, siltstone, shale and coal deposited in fluvial channel, floodplain, and lacustrine environments Thin-bedded nonmarine sandstone, siltstone, shale carbonaceous shale and coal deposited in poorly drained coastal environments Sandstone, siltstone, shale, carbonaceous and coal deposited in coastal plain, alluvial coastal swamp, and lagoonal environments Mesaverde Formation Frontier Formation Inoceramus deformis “Niobrara equivalent” Cody Shale Meeteetse Formation

I (part)

15 MILES

member

Unnamed middle Formation Cloverly Jurassic rocks undivided rocks Jurassic 105 Teapot Sandstone Member Teapot 15 KILOMETERS 10 Scaphites ventricosus Inoceramus deformis Clioscaphites vermiformis Clioscaphites choteauensis Scaphites leei Desmoscaphites bassleri Scaphites depressus Butte Scaphites hippocrepis I Scaphites hippocrepis Scaphites hippocrepis Scaphites depressus 5 Basal sandstone member Shotgun

Figure 6. Regional east-west stratigraphic cross section of Cretaceous rocks in the Wind River Basin. Modified from Finn (2007b). 500 FEET 1,000 1,500 (part) 0

0 NORTHWEST Upper Cretaceous Upper 250 500 Lower ?? METERS Jurassic Cretaceous \\IGSKAHCMVSFS002\Pubs_Common\Jeff\den16_cmrm00_0048_sim_finn\report_figures\figure_06.ai Stratigraphy 9

116° 112° 108° 104° 100° CANADA

48° MONTANA WESTERN NORTH DAKOTA Cody Shale

Niobrara Formation

INTERIOR 44° Cody SOUTH DAKOTA Shale IDAHO

WYOMING NEBRASKA Baxter Shale

SEAWAY Niobrara 40° Formation

NEVADA UTAH KANSAS COLORADO

Mancos Shale

OKLAHOMA

TEXAS 36° EXPLANATION Highlands Conglomerate Coastal plain NEW MEXICO Coastal sandstone Marine shale ARIZONA Calcareous shale/marlstone Limestone Wind River Basin Province boundary 32° 0 100 200 MILES

MEXICO 0 100 200 KILOMETERS

Base from Bureau of Land Management digital data, 2016 Lambert Conformal Conic projection Standard parallels 33° and 45°, Central meridian –108° Latitude of origin 39° North American Datum of 1983 (NAD83)

Figure 7. Paleogeographic reconstruction of the Rocky Mountain region during late Coniacian (Scaphites depressus Zone) time showing major depositional trends. Wind River Basin Province outlined in red. Modified from McGookey and others (1972).

\\IGSKAHCMVSFS002\Pubs_Common\Jeff\den16_cmrm00_0048_sim_finn\report_figures\figure_07.ai 10 Stratigraphic Cross Sections of the Niobrara Interval of the Cody Shale and Associated Rocks, Wind River Basin, WY Regression Cycle Cycle Cycle Claggett Niobrara Greenhorn Trangression ? (part) (part) (part) (part) Pierre Shale Graneros Shale Pueblo, Colorado Carlile Shale (part) Carlile Shale (part) Niobrara Formation Niobrara Formation Niobrara Formation (part) Greenhorn Limestone ? ? (part) (part) (part) (part) Pierre Shale Pierre Shale Carlile Shale NW Black Hills Carlile Shale (part) Niobrara Formation Belle Fourche Shale Greenhorn Formation (part) Member Member Member (part) Wall Creek Wall (undivided) Sage Breaks Belle Fourche Formation River Basin Mesaverde Steele Member

Niobrara Member

Emigrant Gap Member

Western Powder Western Cody Shale Cody Frontier Formation Frontier Lower shaly member shaly Lower (part) Member Member (part) interval Wall Creek Wall Niobrara sandy Upper Formation “chalk kick” Belle Fourche equivalent Mesaverde member

Sage Breaks

Wind River Basin

Emigrant Gap Member

Frontier Formation Frontier Wallace Creek Tongue of Cody Sh. Creek Tongue Wallace Shale Cody Fales Sandstone Member Eastern and southeastern interval Niobrara (part) “chalk kick” equivalent member Member Member Sage Breaks (part)

Wall Creek Wall

Upper sandy Formation member shaly Lower Belle Fourche Mesaverde

Emigrant Gap Member

Wind River Basin Conant Creek tongue

Frontier Formation Frontier Southern and central Shale Cody Alkali Butte member interval Niobrara (part) “chalk kick” member

Member Member Member Basin (part)

Wall Creek Wall

member Sage Breaks equiv.

Upper sandy

Emigrant Gap Formation

Belle Fourche Mesaverde Lower shaly Lower

Frontier Formation Frontier Western Wind River Western Shale Cody Basal sandstone member 75.56 ± 0.11 93.32 ± 0.38 93.82 ± 0.30 75.84 ± 0.26 86.3 ± 0.5 83.6 ± 0.2 89.8 ± 0.3 Age (ma) 94.96 ± 0.50 81.86 ± 0.36 84.43 ± 0.34 95.73 ± 0.61 88.55 ± 0.59 90.21 ± 0.54 90.51 ± 0.45 93.48 ± 0.58 93.68 ± 0.50 93.99 ± 0.72 94.71 ± 0.49 75.19 ± 0.28 87.14 ± 0.39 80.58 ± 0.55 koeneni dakotensis Inoceramus Volviceramus subquadratus crassus Cremnoceramus Magadiceramus hannoverensis “Inoceramus” lundbreckensis Sphenoceramus Western Interior Western azerbaydjanensis inoceramid zones Inoceramus n. sp. Mytiloides hattini Inoceramus pictus Mytiloides scupini Mytiloides incertus Inoceramus howelli Mytiloides kossmati Inoceramus arvanus Inoceramus dimidius Mytiloides mytiloides Cataceramus balticus Mytiloides hercynicus Cremnoceramus waltersdorfensis Cremnoceramus involutus Inoceramus prefragilis Mytiloides puebloensis perplexus Inoceramus ginterensis crenelatus Inoceramus rutherfordi “Inoceramus” gibbosus Inoceramus Inoceramus macconnelli Cordiceramus bueltensis Cordiceramus Inoceramus aff. dimidius Volviceramus Cremnoceramus Magadiceramus “Inoceramus” tenuilineatus deformis Cataceramus subcompressus Cremnoceramus deformis erectus Cremnoceramus Cremnoceramus waltersdorfensis Cremnoceramus Cremnoceramus crassus inconstans Cremnoceramus Cladoceramus undulatoplicatus III sp. (smooth) sp. (smooth) sp. (weak flank ribs) Baculites scotti ammonite zones Western Interior Western Scaphites leei Baculites obtusus Nigericeras scotti Scaphites warreni Baculites reduncus Prionocyclus hyatti Scaphites whitfieldi Baculites perplexus Scaphites depressus Vascoceras birchbyi Vascoceras Baculites maclearni Burroceras clydense Burroceras Scaphites ventricosus Prionocyclus germari Scaphites mariasensis Baculites Neocardioceras juddii Neocardioceras Mammites nodosoides Baculites Baculites asperiformis Acanthoceras bellense Baculites gregoryensis Prionocyclus macombi Vascoceras diartianum Vascoceras Dunveganoceras pondi I Scaphites hippocrepis Watinoceras devonense Watinoceras Scaphites nigricollensis II Scaphites hippocrepis Colinoceras tarrantense Collignoniceras praecox Prionocyclus ferronensis Scaphites preventricosus Desmoscaphites bassleri III Scaphites hippocrepis Collignoniceras woolgari Clioscaphites vermiformis Desmoscaphites erdmanni Didymoceras nebrascense Dunveganoceras conditum Clioscaphites saxitonianus Acanthoceras amphibolum Clioscaphites choteauensis Acanthoceras muldoonense Acanthoceras granerosense Dunveganoceras albertense

Pseudaspidoceras flexuosum

Baculites Plesiacanthoceras wyomingense Dunveganoceras problematicum Euomphaloceras septemseriatum

Middle Lower Middle Middle Upper Upper Upper Lower Lower

Sub- stage Upper Upper Lower Middle Middle

Turonian Cenomanian (part) Cenomanian Campanian (part) Campanian Santonian Coniacian Correlation chart showing stratigraphic relations of mid-Cretaceous rocks in the Wind River Basin and correlation with equival ent at various localities

Stage

UPPER CRETACEOUS (part) CRETACEOUS UPPER CRETACEOUS (part) CRETACEOUS System Series Figure 8. the Powder River Basin and Denver Basin. The diagonal lines represent Niobrara interval in Wind Basin, as def ined this report. Modified from Keefer (1972), Merewether (1996), Finn (2007b), and others (2011). Radiometric ages fossil zones are from Cobban (20 06), McKinney (2015). Sea-level curve is modified from Kauffman and Caldwell (1993). \\IGSKAHCMVSFS002\Pubs_Common\Jeff\den16_cmrm00_0048_sim_finn\report_figures\figure_08.ai Stratigraphy 11 T. T. T. T. N. N. 40 45 N. N. 30 35 R. 80 W. R 80 W Province 106°30' Wind Basin River

WYOMING arch

4,500

Casper 4,500 107° Well control point Well Outcrop control point 4,750 R. 85 W. 5,000 R 85 W

5,250 5,250

5,500

Mountains 5,250 Bighorn Granite Mountains 30' R. 90 W. Creek Tongue Wind River Basin Province boundary limit of tongues Western

4,500 Thickness contour— Contour interval is 250 feet

R 90 W 4,250

5,000 4,750

Western limit of Wallace Western 5,000 4,500 4,250 5,250 108° Mountains 4,000 T N T 35 N 40 T 5 N T 1 T 1 S N R. 95 W. R 95 W of Conant R 95 W R 5 E R 5 E Western limit Western Creek tongue Cody Shale outcrop Precambrian rock Wind River Basin Province

3,750 EXPLANATION

Creek 30'

+

Owl R 1 E 5,250 to 5,500 >5,500 3,500 R 1 E R. 100 W. R 100 W R 100 W R 1 W R 1 W Range 109° 4,250 to 4,500 4,500 to 4,750 4,750 to 5,000 5,000 to 5,250 T 1 S R 5 W R 5 W

Range River 40 MILES T N 45 R. 105 W. T 5 N R 105 W T 1 N T N 30 R 105 W T N T 30' 40 N 35 30

Wind <3,500 3,500 to 3,750 3,750 to 4,000 4,000 to 4,250 40 KILOMETERS

Washakie Thickness of the Cody Shale, in feet 20 30 108° 20 Isopach map of the Cody Shale. This includes interval from top uppermost sandstone in underlying Fronti er Formation to base 10 110° R. 110 W.

10 R 110 W 0 0 Base from Bureau of Land Management digital data, 2016 Lambert Conformal Conic projection Standard parallels 33° and 45° Central meridian – Latitude of origin 39° North American Datum of 1983 (NAD83) Figure 9. of the Mesaverde Formation. In central part basin, interval includes Alkali Butte member F ormation and Conant Creek tongue of the Cody. Creek Tongue of the Cody Shale. In eastern part basin, interval includes Fales Sandstone Member Mesaverde and Wallace Thickness interval 250 feet.

43°

43°30' 42°30' \\IGSKAHCMVSFS002\Pubs_Common\Jeff\den16_cmrm00_0048_sim_finn\report_figures\figure_09.ai 12 Stratigraphic Cross Sections of the Niobrara Interval of the Cody Shale and Associated Rocks, Wind River Basin, WY T. T. T. T. N. N. 40 45 N. N. 30 35 R. 80 W. R 80 W 3,500 Province 3,000 106°30' Wind Basin River

WYOMING

arch 2,500 2,000

Casper 1,750 1,500 107°

2,500 R. 85 W.

2,250 2,000 control point Well Outcrop control point

R 85 W

Mountains Bighorn 2,250 Granite Mountains

30' 2,000

1,750

1,500 1,500 R. 90 W. R 90 W Wind River Basin Province boundary Thrust fault— Sawteeth on upper block Thickness contour— Contour interval is 250 feet

1,750

3,500

108° Mountains T N T 35 N 40 T 5

N T 1 T 1

S N 1,750 R. 95 W. R 95 W 1,750 R 95 W R 5 E

R 5 E 1,750 EXPLANATION Cody Shale outcrop Precambrian rock Wind River Basin Province Creek 30'

1,500

Owl 1,500 R 1 E R 1 E R. 100 W. R 100 W 3,000 to 3,250 3,250 to 3,500 >3,500 R 100 W R 1 W 1,250 R 1 W Range 109° T 1 S 2,000 to 2,250 2,250 to 2,500 2,500 to 2,750 2,750 to 3,000 R 5 W R 5 W

Range River 40 MILES T N 45 R. 105 W. T 5 R 105 W N T 1 N T N 30 R 105 W T N 30' 40 T N 35 30

Wind 40 KILOMETERS <1,250 1,250 to 1,500 1,500 to 1,750 1,750 to 2,000 Washakie 20 30 Thickness of the lower shaly member Cody Shale, in feet 108° Isopach map of the lower shaly member Cody Shale. This includes interval from top uppermost sandst one in underlying 20 10

110° R. 110 W. 10 R 110 W 0 0 Base from Bureau of Land Management digital data, 2016 Lambert Conformal Conic projection Standard parallels 33° and 45° Central meridian – Latitude of origin 39° North American Datum of 1983 (NAD83) Figure 10. Frontier Formation to the base of upper sandy member Cody Shale. Thickness interval 250 feet.

43°

43°30' 42°30' \\IGSKAHCMVSFS002\Pubs_Common\Jeff\den16_cmrm00_0048_sim_finn\report_figures\figure_10.ai Stratigraphy 13 T. T. T. T. N. N. 40 45 N. N. 30 35 R. 80 W. R 80 W Province 106°30'

Wind Basin River 1,000

WYOMING arch 2,000

2,250

Casper

2,500 control point Well Outcrop control point

107° 2,750 R. 85 W. 3,000 3,250 R 85 W

3,000

3,250 3,250

Mountains Bighorn 3,000 Granite

Mountains 2,500 30' 2,750 Wind River Basin Province boundary limit of tongues Western Thickness contour— Contour interval is 250 feet R. 90 W. Creek Tongue R 90 W

3,750

Western limit of Wallace Western

3,250 2,750

2,500

3,000

108° 3,500 Mountains 2,250 T N T 35 N 40 T 5 N T 1 T 1 S N R. 95 W. of Conant R 95 W Cody Shale outcrop Precambrian rock Wind River Basin Province

R 95 W Western limit Western Creek tongue 2,250 R 5 E R 5 E EXPLANATION

Creek

2,000 30' >3,750

2,000 Owl 1,750 R 1 E

2,000 R 1 E R. 100 W. R 100 W R 100 W R 1 W

2,250 R 1 W

Range 2,750 to 3,000 3,000 to 3,250 3,250 to 3,500 3,500 to 3,750 109° T 1 S R 5 W R 5 W

Range River 40 MILES T N 45 1,750 to 2,000 2,000 to 2,250 2,250 to 2,500 2,500 to 2,750 R. 105 W. T 5 R 105 W N T 1 N T N 30 R 105 W T N 30' 40 T N 35 30

Wind 40 KILOMETERS

Washakie 20 30 <1,000 1,000 to 1,250 1,250 to 1,500 1,500 to 1,750 108° Isopach map of the upper sandy member Cody Shale. This includes interval from base to t he 20 Thickness of the upper sandy member Coby Shale, in feet 10

110° R. 110 W. 10 R 110 W 0 0 Base from Bureau of Land Management digital data, 2016 Lambert Conformal Conic projection Standard parallels 33° and 45° Central meridian – Latitude of origin 39° North American Datum of 1983 (NAD83) Figure 11. Mesaverde Formation. In the central part of basin, interval includes Alkali Butte member Format ion and Conant Creek tongue of the Cody. Creek Tongue the Cody Shale. In eastern part of basin, interval includes Fales Sandstone Member Mesaverde and Wallace Thickness interval 250 feet.

43°

43°30' 42°30' \\IGSKAHCMVSFS002\Pubs_Common\Jeff\den16_cmrm00_0048_sim_finn\report_figures\figure_11.ai 14 Stratigraphic Cross Sections of the Niobrara Interval of the Cody Shale and Associated Rocks, Wind River Basin, WY

The Conant Creek tongue of the Cody Shale, informally between Madden anticline and Tepee Flats to the northern named by Szmajter (1993), trends north-south across the central margin of the basin, the upper part of the interval progressively part of the basin. It is separated from the upper sandy member grades into the upper sandy member of the Cody Shale (figs. 6, by an eastward-thinning clastic wedge of marginal marine and 12, and map sheet). West of this line only the basal Niobrara nonmarine rocks, informally referred to as the Alkali Butte strata of the Casper arch and Powder River Basin are repre- member of the Mesaverde Formation by Hogle and Jones sented in the central and western parts of the Wind River Basin (1991) (figs. 6 and 8). The Conant Creek tongue is generally (figs. 6, 8, and map sheet). In the central and western parts of 400 to 1,000 ft thick, but thins to zero where it grades westward the basin, the Niobrara interval ranges from less than 1,000 ft into nonmarine rocks of the Mesaverde Formation (fig. 6). to about 1,800 ft thick (fig. 12). The Wallace Creek Tongue of the Cody Shale occupies There is little fossil data available for the Niobrara inter- the eastern and southeastern parts of the Wind River Basin val in the eastern and southeastern parts of the basin, however, and is stratigraphically higher and younger than the Conant according to Merewether (1996), W.A. Cobban of the USGS Creek tongue to the west. This member is a westward-thinning collected and identified several species of marine mollusks tongue of marine shale that separates the Fales Sandstone from overlying and underlying beds in the western and south- Member at the base of the Mesaverde Formation from the western parts of the Powder River Basin. These fauna indi- upper part of the formation (Barwin, 1961) (fig. 6). The Wal- cate that the Niobrara along the Casper arch and possibly the lace Creek Tongue is nearly 500 ft thick in the southeastern eastern part of the Wind River Basin are likely middle Conia- part of the basin and thins to zero in the northern part of the cian to early Campanian in age (fig. 8). Fossil data reported Coalbank Hills, where it grades into the main part of the by Cobban (1951), Yenne and Pipiringos (1954), Keefer and Mesaverde Formation, (fig. 6). Troyer (1964), Keefer (1972), Landman and Cobban (2007), and files at the USGS fossil collection in Denver, Colorado Niobrara Interval (K.C. McKinney, USGS, written commun., 2015) for sur- face sections near Shotgun Butte, Lander, and Conant Creek The Niobrara equivalent strata in the Wind River Basin indicate that the Niobrara interval below the contact with the are represented by gray to black shale, calcareous shale, marl, upper sandy member is middle Coniacian to late Santonian in and bentonite, with minor amounts of siltstone and sandstone. age in the central and western parts of the basin (fig. 8). In many samples, the more calcareous zones are often charac- terized by varying amounts of coccolith-rich fecal pellets that Sage Breaks Interval appear as distinctive “white specks” similar to those described by Hattin (1975). A persistent zone or high-resistivity peak Merewether and others (1977a, b), and Dunleavy and identified on resistivity logs in the lower 50–300 ft of the lower Gilbertson (1986) correlated the interval of the shaly member shaly member (fig. 4 and map sheet), referred to as the “chalk of the Cody Shale below the “chalk kick” marker and the top kick” marker by Keefer (1972) represents the base of the Nio- of the uppermost sandstone in the Frontier Formation with brara equivalent in the Wind River Basin based on correlations the Sage Breaks Member of the Cody Shale in the western along the Casper arch and into the western Powder River Basin part of the Powder River Basin (figs. 4 and 8). This inter- (Merewether and others, 1977a, b; Dunleavy and Gilbertson, val of noncalcareous marine shale ranges in thickness from 1986; Fox, 1993). The “chalk kick” marker can be traced in the about 300 ft in the southeastern part of the basin thinning to subsurface throughout most of the basin, and based on Ameri- less than 50 ft in the western part, reflecting the backstep- can Stratigraphic Company (AMSTRAT) sample descriptions ping pattern of sandstones in the underlying Frontier Forma- from well cuttings it separates noncalcareous shales in the tion (figs. 6, 13, and map sheet). Ammonite and inoceramid lowermost part of the shaly member from overlying calcareous fossils collected from the underlying Frontier Formation strata (fig. 4, map sheet). The AMSTRAT sample descriptions and within the Sage Breaks interval indicate that it is latest from wells in the eastern and southeastern part of the basin Turonian to middle Coniacian in age in the eastern part of indicate that the top of this calcareous interval corresponds to a the basin, and early to middle Coniacian in age in the central distinctive gamma ray and electric log response (fig. 4 and map western parts (fig. 8). sheet), that has been traced eastward into the top of the Niobr- ara Member (or Formation) along the Casper arch and into the Powder River Basin by Merewether and others (1977a, b) and Dunleavy and Gilbertson (1986). In the eastern and southeast- Acknowledgments ern parts of the basin, the Niobrara interval ranges from about 750 to 1,500 ft thick (fig. 12). The shaly member above the cal- This report benefited from reviews by Ron Johnson, careous Niobrara interval and below the base of the overlying Michael Brownfield, and Dave Ferderer of the U.S. Geologi- sandy member in this area is composed of shales that are less cal Survey (USGS), and their suggestions and comments are calcareous to noncalcareous and commonly contain numer- greatly appreciated. Important information about fossil collec- ous bentonite beds (map sheet). To the west, in the vicinity of tions and locations were provided by K.C. McKinney, curator Coalbank Hills, and extending along a line roughly north-south of the USGS fossil collection in Denver, Colo. Acknowledgments 15 T. T. T. T. N. N. 40 45 N. N. 30 35 R. 80 W. R 80 W Province 106°30' Wind Basin River

WYOMING arch

750

Casper 1,000 107°

R. 85 W. 1,250 R 85 W

1,250 Thrust fault— Sawteeth on upper block Well control point Well Outcrop control point

Mountains

1,500 Bighorn Granite Mountains 30'

1,250 1,250 R. 90 W. R 90 W sandy member grades into upper Approximate position where top of Niobrara

1,500 Wind River Basin Province boundary Thickness contour— Contour interval is 250 feet

108° Mountains 1,750

1,000 T N T 35 N 1,500 40 T 5 N T 1 T 1 S N R. 95 W. R 95 W R 95 W R 5 E R 5 E EXPLANATION

Creek 30'

1,500 Cody Shale outcrop Precambrian rock Wind River Basin Province

Owl 1,500 R 1 E R 1 E

1,250 R. 100 W. R 100 W R 100 W R 1 W R 1 W 1,000 Range 109° 1,250 to 1,500 1,500 to 1,750 >1,750 T 1 S R 5 W R 5 W

Range River 40 MILES T N 45 R. 105 W. T 5 R 105 W N T 1 N T N 30 R 105 W T T N N 30' 40 35 <750 750 to 1,000 1,000 to 1,250 30 Thickness of the Niobrara equivalent interval in the lower part of Cody Shale, feet Wind 40 KILOMETERS

Washakie 20 30 108° Isopach map of the Niobrara equivalent interval in lower part Cody Shale. In eastern basin, includes from 20 10

110° R. 110 W. 10 R 110 W 0 0 Base from Bureau of Land Management digital data, 2016 Lambert Conformal Conic projection Standard parallels 33° and 45° Central meridian – Latitude of origin 39° North American Datum of 1983 (NAD83) Figure 12. the base of “chalk kick” marker to top calcareous zone within lower shaly member Cody Shale. In t he central and western parts basin, the top of interval is base sandy member Cody Shale. Thickness 250 feet.

43°

43°30' 42°30' \\IGSKAHCMVSFS002\Pubs_Common\Jeff\den16_cmrm00_0048_sim_finn\report_figures\figure_12.ai 16 Stratigraphic Cross Sections of the Niobrara Interval of the Cody Shale and Associated Rocks, Wind River Basin, WY T. T. T. T. N. N. 40 45 N. N. 30 35 R. 80 W. R 80 W

Province

106°30' 200 Wind Basin River

WYOMING arch 250

Casper

250 300 107° R. 85 W. R 85 W Thrust fault— Sawteeth on upper block Well control point Well Outcrop control point

300 300

300

Mountains Bighorn Granite Mountains 30' R. 90 W. R 90 W

250 200 Wind River Basin Province boundary Thickness contour— Contour interval is 50 feet 150

300

108° Mountains T N T 35 N 40 150 T 5 N T 1 T 1 S N R. 95 W.

R 95 W 200

R 95 W

R 5 E R 5 E 150 EXPLANATION

100 Creek 30'

50 Cody Shale outcrop Precambrian rock Wind River Basin Province

100 Owl R 1 E R 1 E R. 100 W. R 100 W >300 R 100 W R 1 W R 1 W Range 109° 150 to 200 200 to 250 250 to 300 T 1 S R 5 W R 5 W

Range River 40 MILES T N 45 R. 105 W. T 5 N R 105 W T 1 N T N 30 R 105 W T N 30' 40 T N 35 30 <50 50 to 100 100 to 150 Wind 40 KILOMETERS Thickness of the Sage Breaks equivalent interval in lower part of the Cody Shale, in feet Washakie 20 30 108° Isopach map of the Sage Breaks equivalent interval in lower part Cody Shale. This includes from t he base “chalk kick” 20 10

110° R. 110 W. 10 R 110 W Need base map credit note 0 0 Base from Bureau of Land Management digital data, 2016 Lambert Conformal Conic projection Standard parallels 33° and 45° Central meridian – Latitude of origin 39° North American Datum of 1983 (NAD83) Figure 13. marker to the top of uppermost sandstone in underlying Frontier Formation. Thickness interval 50 feet.

43°

43°30' 42°30' \\IGSKAHCMVSFS002\Pubs_Common\Jeff\den16_cmrm00_0048_sim_finn\report_figures\figure_13.ai References Cited 17

References Cited Finn, T.M., 2007a, Source rock potential of Upper Cretaceous marine shales in the Wind River Basin, Wyoming, chap. 8, of U.S. Geological Survey Wind River Basin Assessment Barwin, J.R., 1961, Stratigraphy of the Mesaverde Formation Team, eds., Petroleum systems and geologic assessment in the southeastern part of the Wind River Basin, Fremont of oil and gas resources in the Wind River Basin Province, and Natrona Counties, Wyoming: unpublished M.A. thesis, Wyoming: U.S. Geological Survey Digital Data Series DDS University of Wyoming, 78 p. 69–J–8, 24 p., CD–ROM. [Also available at https://pubs. er.usgs.gov/publication/ds69J8.] Biggs, Paul, and Espach, R.H., 1960, Dallas Dome, in Petro- leum and natural gas fields in Wyoming: U.S. Bureau of Finn, T.M., 2007b, Subsurface stratigraphic cross sections Mines Bulletin 582, p. 83–84. of Cretaceous and Lower Tertiary rocks in the Wind River Basin, central Wyoming, Wyoming, chap. 9 of U.S. Geo- Cobban, W.A., 1951, Scaphoid cephalopods of the Colorado logical Survey Wind River Basin Assessment Team, eds., group: U.S. Geological Survey Professional Paper 239, 42 p. Petroleum systems and geologic assessment of oil and gas [Also available at https://pubs.er.usgs.gov/publication/pp239.] resources in the Wind River Basin Province, Wyoming: U.S. Geological Survey Digital Data Series DDS 69–J–9, Cobban, W.A., 1969, The Late Cretaceous ammonites 28 p., CD–ROM. [Also available at https://pubs.er.usgs.gov/ Scaphites leei Reeside and Scaphites hippocrepis (DeKay) publication/ds69J9.] in the Western Interior of the United States: U.S. Geological Survey Professional Paper 619, 29 p. [Also available at Fox, J.E., 1993, Stratigraphic cross sections M–M’ through https://pubs.er.usgs.gov/publication/pp619.] R–R’, showing electric logs of Upper Cretaceous and older rocks, Powder River Basin, Wyoming: U.S. Geological Cobban, W.A., Dyman, T.S., and Porter, K.W., 2005, Pale- Survey Oil and Gas Investigations Chart OC–137. [Also ontology and stratigraphy of upper Coniacian—Middle available at https://pubs.er.usgs.gov/publication/oc137.] Santonian ammonite zones and application to erosion Fox, J.E., and Dolton, G.L., 1989, Petroleum geology of the surfaces and marine transgressive strata in Montana and Wind River and Bighorn Basins, Wyoming and Montana: Alberta: Cretaceous Research, v. 26, p. 429–449. U.S. Geological Survey Open-File Report 87–450–P, 41 p. [Also available at https://pubs.er.usgs.gov/publication/ Cobban, W.A., Walaszczyk, Ireneusz, Obradovich, J.D., and ofr87450P.] McKinney, K.C., 2006, A USGS zonal table for the Upper Cretaceous middle Cenomanian-Maastrichtian of the Fox, J.E., and Dolton, G.L., 1996, Wind River Basin Province Western Interior of the United States based on ammonites, (35), in Gautier, D.L., Dolton, G.L., Takahashi, K.I., and inoceramids, and radiometric ages: U.S. Geological Survey Varnes, K.L., eds., 1995 National assessment of United Open-File Report 2006–1250, 45 p. [Also available at States oil and gas resources—Results, methodology, and https://pubs.er.usgs.gov/publication/ofr20061250.] supporting data: U.S. Geological Survey Digital Data Series DDS–30, release 2. Colorado Geological Survey, 2011, Colorado’s new oil boom—the Niobrara: Colorado Geological Survey Rock Gries, R.R., Dolson, J.C., and Raynolds, R.G.H., 1992, Talk, v. 13, no. 1, 11 p. [Also available at http://colorado- Structural and stratigraphic evolution and hydrocarbon geologicalsurvey.org/publications/rocktalk/.] distribution, Rocky Mountain Foreland, in Macqueen, R.W., and Leckie, D.A., eds., Foreland basins and fold belts: De Bruin, R.H., 1993, Overview of oil and gas geology of American Association of Petroleum Geologists Memoir 55, Wyoming, in Snoke, A.W., Steidtmann, J.R., and Roberts, p. 395–425. S.M., eds., Geology of Wyoming: Geological Survey of Hattin, D.E., 1975, Petrology and origin of fecal pellets in Wyoming Memoir no. 5, p. 836–873. Upper Cretaceous strata of Kansas and Saskatchewan: Jour- nal of Sedimentary Petrology, v. 45, no. 3, p. 686–696. Dickinson, W.R., Klute, M.A., Hayes, M.J., Janecke, S.U., Lundin, E.R., McKittrick, M.A., and Olivares, M.D., 1988, Hogle, D.G., and Jones, R.W., 1991, Subsurface geology of Paleographic and paleotectonic setting of Laramide sedi- Upper Cretaceous and Lower Tertiary coal-bearing rocks, mentary basins in the central Rocky Mountain region: Geo- Wind River Basin, Wyoming: The Mountain Geologist, logical Society of America Bulletin, v. 100, p. 1023–1039. v. 28, nos. 2 and 3, p. 13–36.

Dunleavy, J.M., and Gilbertson, R.L., 1986, Madden anti- Jiao, Z.S., and Surdam, R.C., 1997, Characteristics of anoma- cline—Growing giant, in Noll, J.H., and Doyle, K.M., eds., lously pressured Cretaceous shales in the Laramide Basins Rocky Mountain oil and gas fields: Wyoming Geological of Wyoming, in Surdam, R.C., ed., Seals, traps, and the Association, p. 107–157. petroleum system: American Association of Petroleum Geologists Memoir 67, p. 243–253. 18 Stratigraphic Cross Sections of the Niobrara Interval of the Cody Shale and Associated Rocks, Wind River Basin, WY

Johnson, R.C., and Rice, D.D., 1993, Variations in composi- Landman, N.N., and Cobban, W.A., 2007, Redescription of the tion and origins of gases from coal bed and conventional Late Cretaceous (late Santonian) ammonite Desmoscaphites reservoirs, Wind River Basin, Wyoming, in Keefer, W.R., bassleri Reeside, 1927, from the Western Interior of North Metzger, W.J., and Godwin, L.H,. eds., Oil and gas and America: Rocky Mountain Geology, v. 42, no. 2, p. 67–94. other resources of the Wind River Basin, Wyoming: Wyo- ming Geological Association, p. 319–335. 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Finn—Stratigraphic Cross Sections of the Niobrara Interval of the Cody Shale and Associated Rocks in the Wind River Basin, Central WY—SIM 3370

ISSN 2329-132X (online) https://doi.org/10.3133/sim3370