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GEOREF RECORD

Evolution of thick coal deposits in the Powder River basin, northeastern Wyoming

Bion H. Kent
Evolution of thick coal deposits in the Powder River basin, northeastern Wyoming (in Paleoenvironmental and tectonic controls in coal-forming basins of the United States, Paul C. Lyons (editor) and Charles L. Rice (editor))
Special Paper - Geological Society of America (1986) 210: 105-122

Abstract

Wyodak, Big George, and Felix are multibillion-ton coal deposits in Paleocene and Eocene rocks along the eastern flank of the Powder River Basin; they contain beds of subbituminous coal as much as 61 m (200 ft) thick, and average thicknesses are 30.5, 34, and 7.6 m (100, 113, and 25 ft), respectively. These thick coal deposits are elongate north-south; they split to the east and to the west. Laramide structural movements (subsidence and uplift) provided the necessary tectonic control for establishing and prolonging optimal depositional environments and conditions in early Tertiary time. During Paleocene and Eocene time, quiescent periods of thick coal deposition on the eastern flank of the subsiding basin were interspersed with episodes of clastic influx from uplifted eastern source areas. Pivotal effects of western (basin) subsidence and eastern (Black Hills) uplifts produced linear fulcrum areas, in dynamic equilibrium, on the eastern flank of the basin. The fulcrum areas were elongate north-south, parallel to the strike of west-tilted paleoslopes: they were centers for swamp development and coal deposition. Optimal conditions prevailed just west of the fulcrum, where subsidence compensated for upward-building peat accumulation. During prolonged periods of thick coal deposition, those ecosystems were shifted west by eastern uplifts and east by western subsidence. The geometries of the Wyodak, Big George, and Felix coal deposits reflect those processes and indicate how thick coal deposits evolved as products of basin evolution.


ISSN: 0072-1077
EISSN: 2331-219X
Coden: GSAPAZ
Serial Title: Special Paper - Geological Society of America
Serial Volume: 210
Title: Evolution of thick coal deposits in the Powder River basin, northeastern Wyoming
Title: Paleoenvironmental and tectonic controls in coal-forming basins of the United States
Author(s): Kent, Bion H.
Author(s): Lyons, Paul C.editor
Author(s): Rice, Charles L.editor
Affiliation: U. S. Geol. Surv., Denver, CO, United States
Affiliation: U. S. Geol. Surv., Reston, VA, United States
Pages: 105-122
Published: 1986
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 20
Accession Number: 1987-032271
Categories: Petrology of coal
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 1 table, sects., geol. sketch maps
N29°00'00" - N56°00'00", W115°00'00" - W97°00'00"
N43°00'00" - N45°19'60", W107°15'00" - W105°00'00"
N41°00'00" - N45°00'00", W111°04'60" - W104°04'60"
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute.
Update Code: 1987
Program Name: USGSOPNon-USGS publications with USGS authors
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