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U.S. Department of Energy
Office of Scientific and Technical Information

GEOLOGY OF THE POWDER RIVER BASIN, WYOMING AND MONTANA, WITH REFERENCE TO SUBSURFACE DISPOSAL OF RADIOACTIVE WASTES

Technical Report ·
OSTI ID:4762098
The Powder River Basin is a structural and topographic basin occupying an area of about 20,000 square miles in northeastern Wyoming and southeastern Montana. The Basin is about 230 miles long in a northwest-southeast direction and is about 100 miles wide. It is bounded on three sides by mountains in which rocks of Precambrian age are exposed. The Basin is asymmetrical with a steep West limb adjacent to the Bighorn Mountains and a gentle east limb adjacent to the Black Hills. Sedimentary rocks within the Basin have a maximum thickness of about 18,000 feet and rocks of every geologic period are represented. Paleozoic rocks are about 2500 feet thick and consist of marine carbonate rocks and sandstone; Mesozoic rocks are about 9500 feet thick and consist of both marine and nonMarine siltstone and sandstone; and Cenozoic rocks are from 4000 to 6000 feet thick and consist of coal-bearing sandstone and shale. Radioactive waste could be stored in the pore space of permeable sandstone or in shale where space could be developed. Many such rock-units that could be used for storing radioactive wastes are present within the Powder River Basin. Permeable sandstone beds that May be possible reservoirs for storage of radioactive Waste are present throughout the Powder River Basin. These include sandstone beds in the Flathead Sandstone and equivalent strata in the Deadwood Formation, the Tensleep Sandstone and equivalent strata in the Minnelusa Formation, and the Sundance Formation in rocks of preCretaceous age. However, most of the possible sandstone reservoirs are in rocks of Cretaceous age and include sandstone beds in the Fall River, Lakota, Newcastle, Frontier, Cody, and Mesaverde Formations. Problems of containment of waste such as clogging of pore space and chem. ical incompatibility would have to be solved before a particular sandstone unit could be selected for waste disposal. Several thick sequences of impermeable shale such as those in the Skull Creek, Mowry, Frontier, Belle Fourche, Cody, Lewis, and Pierre Formations, occur in rocks of Cretaceous age in the Basin. Limited storage space for liquid waste might be developed in impermeable shale by fracturing the shale and space for calcined or fused waste could be developed by mining cavities (auth)
Research Organization:
Geological Survey, Washington, D.C.
NSA Number:
NSA-17-003155
OSTI ID:
4762098
Report Number(s):
TEI-823
Country of Publication:
United States
Language:
English