Bearpaw Mountains-Eagle Buttes

Region West, Northwest
Mineral systems
Deposit types
Other minerals

Information leading to the delineation of this focus area

Basis for focus area Known deposit types consist of a mineralized intrusive breccia and a quartz-calcite-pyrite stockwork associated with an Eocene trachyte stock that intrudes alkalic intrusive rocks. Gold- and Ag-bearing galena veins are on the margins of latite stocks and shonkinite intrusives.
Identified resources Historical production of gold and silver.
Production Unknown.
Status Past mining. Exploration for gold consisting of drilling, geologic mapping, induced polarization and magnetic surveys, and soil and rock surveys.
Estimated resources Unknown.
Geologic maps Bergantino and others (2002), scale 1:100,000.
Geophysical data Inadequate aeromagnetic and aeroradiometric coverage.
Favorable rocks and structures Favorable rock types are the intrusive rocks (syenites) hosting and supplying mineralizing fluids for gold mineralization. Eocene trachyte stock intrude alkalic intrusive rocks. Gold- and silver-bearing galena veins are on the margins of latite stocks and shonkinite intrusives.
Deposits Bearpaw Mountains (MRDS dep_id: 10008985), Edison prospect, Rex prospect.
Evidence from mineral occurrences MRDS; Pepperberg (1910).
Geochemical evidence Vein material at the Bear's Paw mine contained quartz and calcite impregnated with small crystals of galena, pyrite, iron ore, and scattered crystals of chalcopyrite, with richer streaks of argentiferous galena in pockety geodic masses (Pepperberg, 1910).
Geophysical evidence None.
Evidence from other sources None.
Comments Occurrence of Bi, Ga, Ge, and In are all possibly in this deposit type and mineral system (Hofstra and Kreiner, 2020), but more information is required to determine their abundances in this focus area.
Cover thickness and description Partially exposed at the surface and extends to unknown depth.
Authors Stanley L. Korzeb, Joshua M. Rosera, Kaleb C. Scarberry.
New data needs High resolution geophysics, whole-rock geochemistry for all critical minerals, geologic mapping, lidar.
Geologic mapping and modeling needs 1:24,000 scale geologic mapping.
Geophysical survey and modeling needs High resolution aeromagnetic and aeroradiometric coverage.
Digital elevation data needs Lidar variable, with some complete, some planned/funded but much not covered.