Alluvial model for Eocene Wasatch Formation coal, Powder River basin, Wyoming

Conference · Sun Jul 01 04:00:00 EDT 1984 · Am. Assoc. Pet. Geol., Bull.; (United States)

OSTI ID:5506125

Warwick, P D; Flores, R M; Ferm, J C

The Eocene Wasatch Formation in the Powder River basin, Wyoming, consists of a conglomerate facies (Kingsbury Conglomerate Member) on the western margin of the basin and a coal-bearing facies near the center of the basin. The conglomeratic facies consists of abundant, basally scoured, pebble to boulder conglomerates and sandstones, and minor rooted siltstones. The conglomerates contain abundant sedimentary and subordinate crystalline rock fragments derived from the adjoining Bighorn uplift. The coal-bearing facies comprises dominant coarse to conglomertic sandstones and rooted siltstones and claystones. Minor constituents are fossiliferous limestones, carbonaceous shales, and coals. A thick, widespread coal bed (Felix coal) ranges from 10 to 28 ft (3 to 8.5 m) thick within a 400 mi/sup 2/ (1035 km/sup 2/) area and splits outward from this area into several beds. Where the coal is thick, it is underlain by sandstones and the coal splits are underlain by finer grained deposits. The conglomeratic facies represents wet alluvial-fan deposits consisting of graded gravel bars, channel sands, and finer overbank detritus. These sediments grade eastward into the coal-bearing facies that represents deposits of meandering streams and their adjoining flood plain and backswamp. The locations of the thickest, most widespread coal body and its splits in this facies are governed by depositional topography controlled by differential compaction of the substrate. Where the substrate is poorly compactible channel sandstones, the swamp surface was relatively high and free of sediment influx. Where the underlying deposits are fine grained and more compactible, the resulting low-lying swamp attracted water-borne sediments that interrupted peat accumulation.

• Research Organization: Univ. of Kentucky, Lexington
• OSTI ID: 5506125
• Report Number(s): CONF-8408161-
• Conference Information: Journal Name: Am. Assoc. Pet. Geol., Bull.; (United States) Journal Volume: 68:7
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
011000* -- Coal
Lignite
& Peat-- Reserves
Geology
& Exploration
ALLUVIAL DEPOSITS
CARBONATE ROCKS
CENOZOIC ERA
COAL DEPOSITS
CONGLOMERATES
FEDERAL REGION VIII
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC FORMATIONS
GEOLOGY
LIMESTONE
MINERAL RESOURCES
MONTANA
NORTH AMERICA
POWDER RIVER BASIN
RESOURCES
ROCKS
SANDSTONES
SEDIMENTARY ROCKS
SEDIMENTATION
SHALES
TERTIARY PERIOD
USA
WYOMING