Paleoenvironment of Fort Union Formation, South Dakota
Rocks of Paleocene age are represented in the Cave Hills of northwestern South Dakota by the Ludlow, Cannonball, and Tongue River members of the Fort Union Formation. The Cave Hills are situated within the southern margin of the Williston basin, 80 mi (130 km) north of the Black Hills, South Dakota. Numerous fine-grained, fining-upward sedimentary sequences comprise the Ludlow Member and are attributed to meandering streams occupying a low-gradient lower alluvial to upper deltaic plain. The Cannonball Member is 130 ft (40 m) thick in the North Cave Hills and is represented by two fine-grained, coarsening-upward sandstone mudstone sequences. A distinct vertical succession of sedimentary facies occur within each sequence representing offshore/lower shoreface through upper shoreface/foreshore depositional environment. A north to northeast depositional strike for the Cannonball shoreline is inferred from ripple crest and cross-bed orientations. The basal part of the Tongue River consists of approximately 40 to 50 ft (12 to 15 m) of lenticular sandstone, siltstone, mudstone, thin-bedded lignite, and kaolinite beds representing thin broad channels, point-bar, levee, overbank, and nearshore swamp depositional environments. Massive fluvial channel sandstones measuring several tens of ft in thickness overlie the fine-grained basal Tongue River lithologies. These channel sandstones represent the continued progradation of continental/fluvial/coastal plain depositional environments eastward over the marine sandstones of the Cannonball Member.
- Research Organization:
- Tenneco Oil Exploration and Production, Englewood, CO
- OSTI ID:
- 6433070
- Report Number(s):
- CONF-8309274-
- Journal Information:
- Am. Assoc. Pet. Geol., Bull.; (United States), Journal Name: Am. Assoc. Pet. Geol., Bull.; (United States) Vol. 67:8; ISSN AAPGB
- Country of Publication:
- United States
- Language:
- English
Similar Records
Geology of the Cannonball Formation (Paleocene) in the Williston basin, with reference to uranium potential. Report of investigation No. 57
Paleozoic lithofacies in southwestern Sinai and their depositional environments
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Geology
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CENOZOIC ERA
FEDERAL REGION VIII
GEOLOGIC AGES
GEOLOGY
LITHOLOGY
NORTH AMERICA
RESERVOIR ROCK
ROCKS
SEDIMENTARY ROCKS
SEDIMENTATION
SOUTH DAKOTA
STRATIGRAPHY
TERTIARY PERIOD
USA