8

7

6

5

4

3

2

1

0

17

16

15

14

13

12

11

10

9

?

?

?

?

?

Anvil Points measured section

Sec. 7, T. 6 S., R. 94 W.

8

7

6

5

4

3

2

1

0

Buff

Light

Medium

Dark

Black

Purple

Maroon

Clay

Silt

Very-Fine

Fine

Medium

Coarse

Conglomerate

17

16

15

14

13

12

11

10

9

18

19

?

?

?

Calcareous ripups to 0.5 in

Dol

Dol

Very-lean

Lean

Lean-to-moderate

Moderate

Moderate-to-rich

Rich Rich

Very-rich

Rich-to-very-rich

Very-leanLeanLean-to-moderateModerateModerate-to-rich

Rich-to-very-rich

Very-rich

Fissile

Fissile, dolomitic

Fissile, dolomitic

Ostracode lenses

Ostracode lenses

Ostracode lenses, not well laminated

Ostracode lenses, some clay laminae

A few thin very-fine sandstone beds

50% thin sandstones in lower 2 ft

Non-laminated, highly calcareous, sharp top and base

Sandy in lower 1.5 ft

Mostly non-laminated

Salt crystal casts

Forms big dip slope

20% mudstone interbeds

60% mudstone interbeds

Dolomitic concretions to 4 in with

septarian cracks

Mostly nonlaminated, a few very 

thin, very-fine grained Ss beds

Nonlaminated, slightly fissile, dolomitic concretions 

to 6 in with septarian cracks

Four sandstones, all about 

1.5 ft thick interbedded with

mudstone

Four sandstones, 0.5 to 1.5 ft

 thick interbedded with mudstone

Sharp top and base, dolomitic concretions, smooth 2 in × 6 in

Some medium-to coarse zones

Two thin, ostracode rich very-fine sandstones near base

Mod. fissile, no fizz, slightly silty

Sharp top & base

10% clayey zones

Some medium-grained zones

Upper part non-calc.

Gypsum

Gypsum

Mudstone parting

Indistinct laminae

50% ostracodes

20% Siltstone

Indistinct laminae

Indistinct laminae

Well-laminated, dolomitic

Well-laminated, dolomitic

Gradational base

A few thin Ss beds

Gradational base

Calcareous

Very calcareous

Sharp contacts

20% siltstone beds, indistinct

laminae becoming fairly well

laminate at top

20% silstone

Dolomitic ripups

20% fine-medium grained Ss

10% dolomite beds

0.1 ft th ick,

Sharp contacts

50% sand, algal ripups

A few thin sandstone beds

Indistinct laminae

Mostly indistinct laminae

Indistinct laminae

Indistinct laminae

Indistinct laminae

Indistinct laminae

Siltstone is nonlaminated

Sharp base

Quartz pbls to 0.25 in at top

Indistinct laminae, claystone ripups to 1 in

Indistinct laminae

Indistinct laminae

Indistinct laminae

Indistinct laminae

Dolomitic concretions 8 × 2 in

Algal ripups near top

50% ostracodes

Ripups to 2 in, poss cht. pbls. to 1 in

Indistinct laminae

Indistinct laminae

50% sand

Minor kerogen?

Minor kerogen?

Very-silty, poorly laminated

Very-lean, 8 ft thick

Black, dolomitic

Silty, platy, probably very lean

1 ft lean with 1 in rich at base

2 ft moderate

0.4 ft thick white tuff, slight fizz with dilute acid

non-laminated

9 ft very lean to moderate

lean to very lean

Olive-gray mudstone

Olive-gray mudstone

Some thin rich beds

Some thin rich beds

4 ft lean to moderate

2.5 ft moderate to very rich

5 ft moderate with 1 ft 

lean in center

13 ft lean, hard, platy, dolomitic

Silty, platy, probably 

minor kerogen, syneresis

cracks

Silty, platy, probably 

minor kerogen, syneresis

cracks

Two possible 1 in tuffs, 1 ft apart

Mostly well laminated, 

a few thin dolomite beds

Sandstone beds are rippled

Indistinct laminae, probably interbedded with

mudstone

Carbonate and chert pbls. near top

Mostly indistinct laminae

20% very small ostracodes

Well-laminated, dolomitic

All symmetrical ripples

All symmetrical ripples

Highly calcareous

Clayey dolomite capped by 4 in Ss

All symmetrical ripples,

10% clayey interbeds

25% sandstone with

symmetrical ripples

50% sandstone with

symmetrical ripples

25% sandstone with

symmetrical ripples

A few thin sandstone and 

dolomite beds

Abundant viviparid gastropods near base

SLH

Indistinct laminae

Mostly symmetrical

ripples with some

irregular laminae

All symmetrical ripples,

minor contorting, a few

small ripups near base

Not well laminated, 5% pinching dolomite beds

Three thin sandstones separated by mudstone

A few ostracodes, not well laminated

Slightly fissile, dolomitic

? Fissile

6

7

8

9

10

5

4

3

2

1

0

Buff

Light

Medium

Dark

Black

Purple

Maroon

Clay

Silt

Very-Fine

Fine

Medium

Coarse

Conglomerate

0.3 ft thick, very rich, carbonate ripups

0.3 ft thick, very rich, carbonate ripups

Very-lean

Lean

Lean-to-moderate

Moderate

Moderate-to-rich

Rich

Very-rich

Rich-to-very-rich

6

5

4

3

2

1

0 1.5 ft thick, lean to moderate, marlstone 

ripups, 2 in pinching tuff

8 ft thick, lean, 4 ft rich in middle, 

0.6 ft rippled Ss 2 ft from base

Silty marl grading up into Ss

Small marlstone ripups in lower part

5 ft thick, lean-to very-lean to barren

3 ft thick, very lean to barren

10 ft thick, lean-to very-lean 

18.7 ft thick, very-lean 

38 ft thick, very-lean 

12 ft thick, very-lean 

10 ft thick, very-lean 

1 ft thick, moderate 

1.5 ft thick, lean to moderate 

6 ft thick, lean with 1 ft 

moderate to rich at top

16.5 ft thick, lean with two

1 ft thick moderate beds

1 ft thick, moderate 

1 ft thick, moderate to rich 

18.3 ft thick, moderate to very-rich, 

Mahogany Bed 

2 ft thick tuff 

8 ft thick,, moderate to rich, rich 

beds have marlstone ripups 

Silty marl with possibly 

some very-lean

14 ft thick, very lean with two lean to 

moderate beds 1.5 ft and 2 ft thick 

9 ft thick, moderate, 3 tuffs to 0.2 ft 

1.5 ft thick, moderate with very rich 

beds containing marlstone ripups 

Some possible very lean 

Olive mudstone grading up 

into white marl 

0.3 ft thick, calcareous inconspicuous bedding 

No dark grains 

Insect parts 

Some thin very-fine Ss beds 

Mostly lean oil shale with three 

thin, very-rich blue beds with 

marlstone ripups, includes a 2.4 ft 

thick Ss with troughs 

10 ft thick, lean-to very-lean 

3.7 ft thick, moderate 

11 ft thick, very lean to moderate

11 ft thick, very lean to moderate 

with a 1.5 ft thick very rich bed

10 ft thick, lean-very lean to barren

Bidirectional troughs

Dolomitic mudstone

Very lean and dolomitic mudstone

Algal ripups at top

Algal ripups at top

Barren white marlstone

Barren white marlstone

Barren white marlstone

Barren white marlstone

Barren white marlstone

Dolomitic siltstone with very fine

sandstone beds grading up into 

barren marl to very-lean

Minor barren white marlstone

Barren white marlstone

8

7

6

5

4

3

2

1

0

Buff

Light

Medium

Dark

Black

Purple

Maroon

Clay

Silt

Very-Fine

Fine

Medium

Coarse

11

10

9

2% dark chert

2% dark chert

Indistinct laminae, 2% dark chert

Slightly fissile

Slightly fissile

Fissile

Fissile

Fissile

Fissile

Mudstone, not fissile

Moderately fissile

No bedding seen

No bedding seen

2 in. ostracodal limestone

No bedding seen

Thin Ss and ost.beds

0.3 ft thick

2% dark chert

2% dark chert

2% dark chert

2% dark chert

Very-slightly calcareous

2 inch thick tuff

Plant remains througout

Slightly fissile

Slightly fissile, dolomitic

Slightly fissile, dolomitic

4 in ostracodal Ls overlying Ss

Mud ripups near top

0.2 ft thick, large calcite crystals

Weakly laminated, some 1–2 in

thick dolomite beds near base

Weakly laminated, dolomitic,

becoming siltier towards top

Tan massive siltstone

Becomes interbedded with

very-fine Ss near top

6 in thick, well laminated, laterally-linked hemispheriods

7 ft thick fissile oil shale bed, 

lower 5 ft lean, upper 2 ft rich

7 ft thick fissile oil shale bed, 

alternating rich and lean zones

Slightly fissile

Sandy

10 ft thick, lean to very-lean fissile

Algal ripups, black chert grains

Dolomitic, 3 in ost. Ls near base

Interbedded siltstone and mudstone

Sandy ostracodal limestone

1.5 ft thick algal layer

Calcareous and dolomitic, some

thin, rust-weathering siltstones

0.4 ft thick, abundant rusty grains

2 ft thick

Full of marlstone ripups

Moderately rich, fissile, 2 ft thick

Moderately rich, fissile, 0.5 ft thick

Dolomitic, moderately fissile

Indistinct bedding, syneresis cracks on bottom

Marlstone ripups to 3 ×.25 in

10–20% rounded buff grains

10–20% rounded buff grains, 1.5 ft thick

30–40% small marlstone ripups

Rare small marlstone ripups

3 in thick, mapped as yt (yellow tuff bed)

Full of marlstone ripups

Interbedded with silstone in

lower 2 ft, a few ripups

Marlstone ripups to 4 ×.5 in

Dolomitic

Dolomitic

Mudstone parting

Algal ripups to 0.5 in

Ss beds to 3 in, dolomitic concretions to 3 × 1 in

Weakly laminated, dolomitic, 

a few ostracodes

Very lean, 1 ft thick

Weakly laminated, dolomitic

Mudstone bed near top

Dolomite beds to 4 in thick

Dolomitic, slightly fissile

Possibly minor kerogen

Dolomitic

Dolomitic

Dolomitic

Dolomitic

Fissile, 1 in dolomite bed near top

Lean, 4 ft thick

Lean to moderate, fissile, 4 ft thick

5% chert, sparry calcite cemented

Lean, fissile, 2 ft thick

Fissile

Fissile

White barren marl

White barren marl

Moderate-rich, 3 ft thick, thin Ss

very-lean to rich, 9 ft thick

Grades upwards from very-lean to mod.

Marlstone ripups

-4

-5

-6

-7

-8

-9

-10

-11

-12

-13

-14

-15__

-1

-2

-3

0 20 40 60 80 100

0 20 40 60 80 100

C613R

General Petroleum Corp.

28–19–G

SE1⁄4 SW 1⁄4 SW1⁄4

sec. 19, T. 2 S., R. 95 W.

KB 7,816 ft

500

1,000

1,500

2,000

2,500

3,000

3,500

0

0 20 40 60 80 100

0 20 40 60 80 100

500

1,000

1,500

2,000

2,500

3,000

0

C–655R

Petroleum Inc

Government-Helmke 1

NW 1⁄4 NW1⁄4 sec. 31, T. 1 S., R. 95 W.

GL 6,650 ft

20

20

21

22

23

24

25

26

27

Estimated oil yield

Estimated oil yield

Estimated oil yield

Estimated oil yield

Buff

Light

Medium

Dark

Black

Purple

Maroon

Clay

Silt

Very-Fine

Fine

Medium

Coarse

Conglomerate

Muscovite

Fissile

Abundant muscovite

Muscovite,

algal breccia

1% dark grains

Muscovite

Muscovite

Muscovite

No dark grains

1% dark grains

20% rusty grains,

muscovite

Muscovite

Sharp base

Muscovite

Muscovite

Muscovite

Possible lateral 

accretion

Claystone partings

Sharp base

Gypsum

Bone?

Algal ripups?

Gypsum

moderate bed d 1 5 f d 2 f hi k s 1 5 ft and 2 ft thick

moderate to rich at top

0 20 40 60 80 100

0 20 40 60 80 100

C–329

Carter Oil Co.

Opportunity 2

2,150 FEL, 850 FNL

sec. 28, T. 1 N., R. 96 W.

GL 7,080 ft

500

1,000

1,500

2,000

0

0 20 40 60 80 100

C0098

U.S. Navy/USBM

Core hole C (NOSR 1)

90 FWL, 2,040 FNL

Sec. 12, T. 6 S, R. 95 W.

GL 8,586

300

+300

200

+200

100

+100

+100

400

600

500

700

800

900

1,100

1,000

1,200

1,300

1,400

1,500

1,600

1,700

1,800

1,900

2,000

2,500

TD 1,684 ft

0 20 40 60 80 100

0 20 40 60 80 100

C0342

U.S. Geological Survey

Core hole 78–1

1,950 FEL, 2,400 FSL

sec. 6, T. 4 S., R. 94 W.

GL 7,120 ft

TD 232 ft

0 20 40 60 80 100

0 20 40 60 80 100

C0071

U.S. Navy/USBM

Core hole G (NOSR 1)

2,000 FEL, 1,750 FNL

sec. 3, T. 5 S., R. 94 W.

GL 8,795 ft

500

1,000

0

500

1,000

1,500

2,000

2,500

3,000

3,500

0

0 20 40 60 80 100

C0568R

Equity Oil Co.

Miller Government 1

1,775 FEL, 1,900 FNL

sec. 28, T. 3 S., R. 95 W.

KB 7,695 ft

TD 3,718 ft

0 20 40 60 80 100

0 20 40 60 80 100

0 20 40 60 80 100

C0271

Carter Oil Co.

Upper Piceance Creek 2

1,950 FWL, 1,250 FSL

sec. 9, T. 3 S., R. 95 W.

GL 6,710 ft

TD 2,402 ft

500

1,000

1,500

2,000

2,500

0 20 40 60 80

0 20 40 60 80 100

C0345

U.S. Geological Survey

Core hole 78–3

100 FEL, 100 FSL 

sec. 14, T. 2 S., R. 95 W.

GL 7,560 ft

TD 303 ft

500

1,500

2,000

1,000

500

1,500

100

1,000

1,500

2,000

2,500

3,000

0

+300

+200

+100

0

+600

+500

+400

+800

+700

200

300

400

+100

0

100

+300

+200

+500

+50

+400

+100

0

+300

+200

+400

+300

+200

+100

+600

+500

+400

+700

Oil yield (gallons per ton)

Oil yield (gallons per ton)

Oil yield (gallons per ton)

Oil yield (gallons per ton)

Oil yield (gallons per ton)

Oil yield (gallons per ton)

Oil yield (gallons per ton)

Oil yield (gallons per ton)

Oil yield (gallons per ton)

Oil yield (gallons per ton)

Oil yield (gallons per ton)

Oil yield (gallons per ton)

Oil yield (gallons per ton)

Oil yield (gallons per ton)

Oil yield (gallons per ton)

Oil yield (gallons per ton)

Oil yield (gallons per ton)

Oil yield (gallons per ton)

Creek or river Highway

Core hole

Cross section

T

2

N

T

1

N

T

1

S

T

2

S

T

3

S

T

4

S

T

5

S

T

8

S

T

7

S

T

6

S

108°30' 108°00’

City or town

Area underlain by the Mahogany bed County line 

EXPLANATION

Colorado

T 102 W T 101 W T 99 W T 98 W T 97 W T 96 W T 100 W T 95 W T 94 W

40°00’

39° 30'

Piceance

White River

Meeker

Rangely

Rifle

Rio Blanco

DeBeque

Parachute

Colorado River

Creek

Creek

GARFIELD

RIO BLANCO

GARFIELD

MESA

Roan

White

River

Index map

Oil yield— In gallons per ton

Contact—Approximately located

Cross section scale

USGS number

Company name

Well name

Location (section, township, range)

0

100

150

200 FEET

Total depth of well— in feet

C0189

Superior Oil Co.

Core hole 05

sec. 10, T. 1 N., R. 97 W.

KB (kelly bushing) in ft

GL (ground level) in ft

TD 1,393 ft

Pelcypod

Climbing ripples

Symmetrical ripples

Horizontal stratification

Internal characteristics

Irregular stratification

Contorted stratification

Claystone, clayshale

or mudstone

Siltstone

Sandstone

Lithology

Oil Shale

Calcareous or dolomitic 

rock

Ostracodes

Gastropods

Oolites

Oncolites

Calcareous sandstone

Calcareous siltstone

Thin beds of dolomite

Pebbles and cobbles

Cross-stratification, less than 1 ft high

Cross-stratification, 1 to 3 ft high

Cross-stratification, greater than 3 ft high

Cross-stratification, 

less than 15 degrees

Ripples, nonspecific Fish bones or fish scales

Plant remains

Tuff

Stromatolites

Large-scale

lateral 

accretion

10

11

12

Mainly climbing ripples

Buff to white

Light gray/green

Medium gray/green

Dark gray/green

Black

Purple

Maroon

Pebbles and cobbles

Coarse sand

Medium sand

Fine sand

Very-fine sand

Silt

Clay

Covered

Irregular 

scour surface

Pinches out

along outcrop

Thins along 

 outcrop

Partially 

covered

Unweathered color Lithology Grain-size range Internal characteristics

Key to Measured Sections

Hundreds of

feet

Carbonaceous or woody

material

Ripup clasts

Limestone

Veinlets

Fossil bones

Mudcracks

Hummocky stratification

SLH Space linked hemispheroids 

Indistinct laminae

Feature near top of bed

50

EXPLANATION

T. 102 W. T. 101 W. T. 100 W. T. 99 W. T. 98 W. T. 97 W. T. 96 W. T. 95 W. T. 94 W. T. 93 W.

Smith Gulch

A

Olive gray

Offset in 

section

64

139 64

Hay Gulch

13

Measured section

139

Parachute

Creek

13

70

0 6 12 MILES

0 6 12 KILOMETERS

Rio

Blanco

Anvil

Points

C0071

C0098

C0613R

C0568R

C0342

C0271

C0655R

C0345

C0329

B

B'

Anvil

Points

Fly larva

Dol Dolomite concretions

Carbonate-rich oil shale (>10 gallons per ton) 

Carbonate-rich oil shale (<10 gallons per ton) 

Clay-rich oil shale (>10 gallons per ton) 

Clay-rich oil shale (<10 gallons per ton) 

Variegated mudstone, sandstone, and siltstone 

Carbonate-rich mudstone with ostracodal,

oolitic, and stromatolitic limestone and 

minor sandstone and siltstone

Carbonate-rich mudstone with sandstone and 

siltstone and minor ostracodal, oolitic, and 

stromatolitic limestone

Volcaniclastic rocks 

Mostly lean oil shale with some volcaniclastic

material

Green River Formation

Anvil Points Member (lower part) Garden Gulch Member Parachute Creek Mbr. Anvil Points Mbr. (upper part)

Stratigraphic subdivisions

from Pipiringos

and Johnson (1976)

Pisolite bed

First algal zone 

Yellow tuff bed

Lower ostracodal 

limestone 

Stratigraphic subdivisions

from O’Sullivan (1986) Green River Formation Parachute Creek Member Uinta Formation (part) Wasatch Formation (part) Anvil Points Member

Uinta Formation

Uinta Formation

Uinta Formation

Uinta Formation

Uinta Formation

Uinta Formation

Uinta Formation

Uinta Formation

Uinta Formation

Uinta Formation

Uinta Formation

Uinta Formation

Uinta Formation

Uinta Formation

Uinta Formation

R–1 oil shale zone

R–0 oil shale zone (part)

L–1 oil shale zone

L–0 oil shale zone

R–2 oil shale zone

R–2 oil shale zone

L–2 oil shale zone

L–2 oil shale zone

R–3 oil shale zone

R–3 oil shale zone

L–3 oil shale zone

L–3 oil shale zone

R–4 oil shale zone

R–4 oil shale zone

L–4 oil shale zone

L–4 oil shale zone

R–5 oil shale zone

R–5 oil shale zone

L–5 oil shale zone

L–5 oil shale zone

R–6 oil shale zone

R–6 oil shale zone

B–groove

A–groove

Mahogany oil shale zone

R–0 oil shale zone (part)

L–1 oil shale zone

R–1 oil shale zone

L–0 oil shale zone

R–2 oil shale zone

L–2 oil shale zone

R–3 oil shale zone

L–3 oil shale zone

R–4 oil shale zone

L–4 oil shale zone

R–5 oil shale zone

L–5 oil shale zone

R–6 oil shale zone

B–groove

A–groove

Mahogany oil shale zone

Mahogany oil shale zone

Mahogany oil shale bed

Anvil Points Member

of O’Sullivan (1985)

Parachute Creek Member

of O’Sullivan (1985)

Garden Gulch

Member

Anvil Points Member

Parachute Creek

Member

Coughs Creek Tongue of Green River Formation (O’Sullivan, 1985)

Marlstone at Jackrabbit Ridge (O’Sullivan, 1985)

A–groove

Mahogany oil shale zone

Mahogany oil shale zone

Mahogany oil shale bed

Mahogany oil shale bed

3.5 miles 2.5 miles 5.5 miles 5.8 miles 4.5 miles 4.7 miles 2.7 miles 4.5 miles 1.0 miles 7.5miles 1.55 miles 

Base of Long Point Bed of Green River Formation (Johnson, 1984)

Hay Gulch measured section

Sec. 36, T. 1 N., R. 96 W.

Sec. 1, T. 1 S., R. 96 W.

Rio Blanco measured section

Sec. 32, T. 3 S., R. 94 W.

Sec. 5, T. 4 S., R. 94 W.

 Smith Gulch measured section

Sec. 14, T. 1 N., R. 96. W 

B

North

B'

South

Very-leanLeanLean-to-moderateModerateModerate-to-rich

Rich

Rich-to-very-rich

Very-rich

U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Map 3276

Sheet 2 of 2

Pamphlet accompanies map

Cross section B–B’ of the Eocene Green River Formation Along the East Margin of the Piceance Basin, Western Colorado

By

Ronald C. Johnson

2014

Any use of trade, firm, or product names is for descriptive purposes only and does 

not imply endorsement by the U.S. Government.

Although this information product, for the most part, is in the public domain, it also 

contains copyrighted materials as noted in the text. Permission to reproduce 

copyrighted items must be secured from the copyright owner.

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/ 

Publishing support provided by: 

Denver Publishing Service Center

Manuscript approved for publication August 9, 2013

This and other USGS information products are available at

http://store.usgs.gov/ 

U.S. Geological Survey

Box 25286, Denver Federal Center

Denver, CO 80225

To learn about the USGS and its information products visit

http://www.usgs.gov/ 

1-888-ASK-USGS

This report is available at:

http://pubs.usgs.gov/sim/3276

Suggested citation:

Johnson, R.C., 2014, Detailed cross sections of the Eocene Green River Formation 

along the north and east margins of the Piceance Basin, western Colorado, using 

measured sections and drill hole information: U.S. Geological Survey Scientific 

Investigations Map 3276, 11 p., 2 sheets, http://dx.doi.org/10.3133/sim3276/.

ISSN 2329-132X (online)

http://dx.doi.org/10.3133/sim 3276