Depositional systems and coal occurrence in the Fort Union Formation (Paleocene), Powder River Basin, Wyoming and Montana

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1984

OSTI ID:6169671

Ayers, Jr, W B

The Powder River Basin is a Laramide foreland basin which was formed as a structural and depositional entity in the Paleocene and was filled by fluvial-deltaic, paludal, and lacustrine sediments of the Fort Union Formation. A regional subsurface study shows that, as a result of rapid subsidence in the middle paleocene, a lake (Lebo Shale Member) formed along the axis of the Powder River Basin and rapidly transgressed an area greater than 10,000 sq mi. (25,900 sq km). From middle through late Paleocene, Lake Lebo was filled peripherally by fluvially dominated deltas (Tongue River Member). Primary fill was from: (1) the east by elongate deltas fed by suspended-load fluvial systems issuing from the Black Hills and; (2) the southwest by lobate deltas fed by mixed-to-bed-load streams sourced to the west. Secondary fill was from the northwest by an elongate delta fed by a suspended-load fluvial system flowing through the Bull Mountain trough. A detailed study of Tongue River coal seams near the center of the basin shows that coal occurrence is facies controlled.

• Research Organization: Texas Univ., Austin (USA)
• OSTI ID: 6169671
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
011000* -- Coal
Lignite
& Peat-- Reserves
Geology
& Exploration
COAL DEPOSITS
DEPOSITION
FEDERAL REGION VIII
GEOLOGIC DEPOSITS
GEOLOGIC HISTORY
GEOLOGY
GROUND WATER
HYDROGEN COMPOUNDS
MINERAL RESOURCES
MONTANA
NORTH AMERICA
OXYGEN COMPOUNDS
POWDER RIVER BASIN
RESOURCES
SEDIMENTS
STRATIGRAPHY
USA
WATER
WYOMING