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Paleogeographic evolution of the latest Cretaceous and Paleocene Wind River Basin

Conference · · Mountain Geologist; (United States)
OSTI ID:5528924
 [1];  [2]
  1. Lamont-Doherty Geological Observatory, Palisades, NY (United States)
  2. Chevron Research Tech. Co., Richmond, CA (United States)

Lithofacies analysis and palynologic age-dating of the lower part of the Fort Union Formation in the Wind River Basin reveal differences in age and depositional environment between the Casper Arch to the north and the Rattlesnake Hills to the south. Along the Casper Arch, the lower part of the Fort Union Formation is of latest cretaceous and earliest Paleocene age and is comprised of large ribbon-channel sandstone bodies that record a large river system that flowed to the northwest, parallel and adjacent to the rising Casper Arch. These strata are overlain by lacustrine-margin (Shotgun Member) and lacustrine (Waltman Shale Member) facies. To the south, along the Rattlesnake Hills, the lower part of the Fort Union Formation is of Late Paleocene age and is comprised of laterally continuous sheet sandstone bodies which record a river system that flowed to the north, away from the rising Wind River and Granite mountains. These strata overlie an unconformity that spans Early Paleocene time and are time equivalent with the Late Paleocene lacustrine deposits exposed to the north along the Casper Arch. Together these strata record the initiation of uplift along the Casper Arch and the subsequent infilling of the Wind River Basin during Paleocene time.

OSTI ID:
5528924
Report Number(s):
CONF-8905393--
Journal Information:
Mountain Geologist; (United States), Journal Name: Mountain Geologist; (United States) Vol. 28:2-3; ISSN MOGEA; ISSN 0027-254X
Country of Publication:
United States
Language:
English