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Subsurface geology of Upper Cretaceous and Lower Tertiary coal-bearing rocks, Wind River Basin, Wyoming

Conference · · Mountain Geologist; (United States)
OSTI ID:5803928
 [1];  [2]
  1. Dept. of Environmental Quality, Cheyenne, WY (United States)
  2. Geological Survey of Wyoming, Laramie (United States)

A refined stratigraphic framework has been established for more than 20,000 ft of Upper Cretaceous through lower Eocene sedimentary rocks in the Wind River Basin, Wyoming. This study uses a much larger data base than previously available, including a correlation net of 325 geophysical well logs (electric logs showing resistivity, spontaneous potential and/or gamma ray-neutron curves), 36 drill holes with palynological age dates, 80 drill hole lithology logs, and limited surface exposures. Significant results and conclusions from this study include: (1) The lower part of the Mesaverde Formation intertongues with marine sandstones and shales in the upper part of the Cody Shale to the east and with marine sandstones in the lower part of the Mesaverde Formation in the Bighorn Basin to the north. (2) An unconformity between the Upper Cretaceous Mesaverde Formation and the overlying Paleocene Fort Union Formation in the southwestern part of the Wind River Basin can be correlated for more than twenty miles in the subsurface. (3) During the latest Cretaceous and Paleocene, more than 7,000 ft of Lance Formation and more than 8,500 ft of Fort Union Formation were deposited in the northeastern part of the basin. Ponding during the Paleocene occurred primarily in the northeastern Wind River Basin with the deposition of 2,800 ft of shale and siltstone in the Waltman Shale Member of the Fort Union Formation. (4) The Lance and Fort Union formations occur in the subsurface throughout much of the basin; however, the Lance and the underlying Meeteetse Formation were eroded in the western part of the basin. (5) Formation thicknesses are controlled locally, in part, by synorogenic structural features that were developing during the deposition of sediments. (6) Regional coal isopach and isopleth maps indicate possible target areas for coal and related hydrocarbon exploration.

OSTI ID:
5803928
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