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

Dubois Quadrangle, Idaho and Montana

Technical Report ·
OSTI ID:6344144

Within the Dubois Quadrangle (Idaho and Montana), environments favorable for uranium deposits, based on National Uranium Resource Evaluation criteria, occur in the McGowan Creek Formation and within some Tertiary sedimentary basins. The Mississippian McGowan Creek Formation consists of uraniferous, black, siliceous mudstone and chert with minor porous sedimentary channels. In the southern Beaverhead Mountains it has been fractured by a bedding-plane fault, and uranium has been further concentrated by circulating groundwater in the porous channels and brecciated zones, both of which contain about 200 ppM uranium. The northern parts of the Pahsimeroi River, Lemhi River, Medicine Lodge Creek, Horse Prairie, and Sage Creek Basins are considered favorable for sandstone-type uranium deposits. Evidence present includes suitable source rocks such as rhyolitic flow breccia, laharic deposits, or strongly welded tuffs; permeable sediments, including most sandstones and conglomerates, providing they do not contain devitrified glass; suitable reductants such as lignite, pyrite, or low-Eh geothermal water; and uranium occurrences.

Research Organization:
Geoexplorers International, Inc., Denver, CO (USA)
DOE Contract Number:
AC13-76GJ01664
OSTI ID:
6344144
Report Number(s):
GJQ-008(81); ON: DE81024328
Country of Publication:
United States
Language:
English