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Aerial radiometric and magnetic reconnaissance survey of portions of Arizona, Idaho, Montana, New Mexico, South Dakota and Washington. Volume 2-E. Great Falls Quadrangle. Final report

Technical Report ·
OSTI ID:5956102

The results of a high-sensitivity, aerial, gamma-ray spectrometer and magnetometer survey of the Great Falls Quadrangle, Montana, are presented. Statistical and geological analysis of the radiometric data revealed 92 uranium anomalies worthy of field-checking as possible prospects. Four anomalies associated with Mississippian rocks may be indicative of uranium in Mission Canyon Limestones. Three anomalies in Jurassic rocks may point to mineralization in the Morrison Formation. The Cretaceous Colorado Shale has the greatest surface exposure in this quadrangle, and it also registers the greatest number of anomalies. Although this unit contains shale and bentonite that may be uranium-rich, the 64 anomalies associated with this unit are considered significant in that possible sandstone-type uranium deposits may be discovered. Other units that may host sandstone-type deposits include the Eagle Sandstone and the Kootenai Formation. Abundant carbonaceous material in the Eagle Sandstone, particularly in the northeast, may have caused the precipitation of uranium from ground waters that may have leached uranium from bentonite in the Colorado Shale. Six anomalies pertain to the Eagle Sandstone, and five are related to the Kootenai Formation. Four anomalies associated with Cretaceous volcanics may point to possible vein-type deposits. Anomalies related to Quaternary deposits may be significant in that they could reflect uranium-rich source rocks that may contain uranium mineralization.

Research Organization:
Texas Instruments, Inc., Dallas (USA)
DOE Contract Number:
EY-76-C-13-1664
OSTI ID:
5956102
Report Number(s):
GJBX-126(79)(Vol.2E)
Country of Publication:
United States
Language:
English