Unified Stratigraphy and Depositional Systems -...

Unified Stratigraphy and Depositional Systems - Green

River Oil Shale in the Piceance & Greater Green River Basins,

Colorado & Wyoming

J. Frederick Sarg, and Yuval BartovColorado School of Mines

Alan CarrollUniversity Wisconsin, Madison

Tim LowensteinSUNY, Binghamton

Lake Piceance

Green River Lakes, Western USA

Stratigraphic section, Green River Formation, Piceance Creek basin.

Oil Shale resources of the Green River Formation: commonly saline lake deposits.

from Dyni, 2006.

Saline Lakes are ideal environments for the production and preservation of organic matter

107-108 cells/ml

Lake Piceance

Green River Lakes, Western USA

Underfilled Facies

• Dominantly aggradational

• Variable quality oil shales

• World-class trona deposits

Wilkins PeakWilkins Peak

TronaTrona

Bird TracksBird Tracks

Wilkins Peak MemberWilkins Peak Member

(Carroll and (Carroll and BohacsBohacs 2001)2001)

Consistently oil prone, low diversity flora Consistently oil prone, low diversity flora

Balanced-Fill Facies

• Mixed aggradation, progradation

• High quality oil shales

• Fish fossils

Stromatolite

Lower Lower LaCledeLaClede BedBed

BalancedBalanced--Fill Organic MatterFill Organic Matter

(Carroll and (Carroll and BohacsBohacs 2001)2001)

Very organicVery organic--rich, consistently oilrich, consistently oil--proneprone

Mahogany zone

R6

SB13

SB 12

SB11Balanced Fill

Over Filled

NE Piceance Basin – Hay Gulch

Western Piceance Basin ‐ Douglas Creek Arch

Lake Piceance

Green River Lakes, Western USA

Sediment Accumulation Rates

(Carroll et al., in prep.)

• High GR responses lie stratigraphically below erosional surfaces

• Increase in GR response caused by increased water influx to lake (highstands), 

associated with radioactive mineral deposition

L1

R1260

330

360

390

Hei

ght

(ft)

3

4

SB 4

Piceance Basin ‐ Douglas Pass:  Outcrop GR

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High frequency cycles

Western Piceance Basin ‐ Douglas Creek Arch

S N

Upper salt

Lower salt

Mahogany Zone

R-0

Sandstone

Sandstones Oil Shale

R-2

R-1

R-3R-4

R-5R-6

R-7

Carbonates

Colors represent sequences

Sequence Section: Douglas Pass‐Basin Center

Mahogany = Lower/Upper LaClede Bed Boundary (~49 Ma)Mahogany = Lower/Upper LaClede Bed Boundary (~49 Ma)

South North

(Smith, Carroll, and Singer, in press)

Chronostratigraphy

Age (Ma)

48

49

50

51

52

53

54

14

13

12

11

10

9

8

7

6

5

4

3

2

1

Piceance Creek Seqs. (400k)

Greater Green River

48.8

49.6 Sixth Lane

y

Wilkins Peak

TiptonGarden Gulch

Parachute Creek

Douglas Creek

51.3 Rife

51.8 Scheggs

Wasatch

49.8 Layered50 Main

50.4 Grey50.6 Boar

50.8 Firehole

Mbr.AgesGGRPC

Lake Type

Under Filled

Balanced Fill

Overfilled

HH T

TN

H – haliteN - nahcoliteT - trona

A

F or DI

N

N

Luman

Smith, Carroll, and Singer (2008)Smith, Carroll, and Singer (2008)

WashakieWashakieBasinBasin

Synoptic Evolution

Stratigraphy – Primary Controls on Lake History1. Test correlation model with additional age determination in 

Piceance and Greater Green River basins.

2. Gather outcrop gamma ray surveys in Wyoming to correlate into the subsurface, and integrate Fischer Assay data.

3. Continued sedimentology and stratigraphy of mixed clastic‐carbonate basin margin sediments in the Piceance basin to improve understanding of relationship of lake evolution and organic richness.

Evaporites – Evolving Lake Water Chemsitry1. Sedimentology/mineralogy of evaporite facies to define primary 

minerals, and reconstruct lake water chemistries and temperatures (XRD, petrography, sedimentary structure, fluid inclusions).

UNIFIED STRATIGRAPHIC FRAMEWORK & PREDICTIVE MODEL OF GREEN RIVER OIL SHALE RICHNESS

FUTURE PROJECT WORK