Adel Mountain Volcanics

Region West, Northwest
Mineral systems
Deposit types
Other minerals

Information leading to the delineation of this focus area

Basis for focus area Laccoliths and dikes of trachyandesite, syenite, monzonite, trachybasalt, and quartz monzonite porphyry. Precious metal lode veins in adjacent Proterozoic strata (Belt Supergroup) in the Wolf Creek District of the greater Helena Mining District (Schmidt, 1978).
Identified resources Historical production of copper and gold.
Production Wolf Creek district (1890-1928): production of Cu and Au (Pardee and Schrader, 1933); briefly worked and produced from 1960-1961 (Schmidt, 1978).
Status Past mining.
Estimated resources Unknown.
Geologic maps Mudge and others (1982), scale 1:250,000; Soward (1975a, b), scale 1:24,000; Vuke (1999), scale 1:24,000; Schmidt (1977), scale 1:24,000; Vuke (2000), scale 1:100,000.
Geophysical data Inadequate aeromagnetic and aeroradiometric coverage; See Kleinkopf and Mudge (1972).
Favorable rocks and structures Monzonite laccoliths, precious metal lode veins in Proterozoic sedimentary rocks adjacent to the volcano, and localized epithermal targets in andesite.
Deposits Wolf Creek district: New Era (MRDS dep_id: 10221403), Herwood (MRDS dep_id: 10207756), Hudson mine (MRDS dep_id: 10098033).
Evidence from mineral occurrences MRDS; Pardee and Schrader (1933).
Geochemical evidence Antimony, arsenic-bearing sulfosalts (tennantite-tetrahedrite), and barite are reported to occur in ore from the Wolf Creek district (Schmidt, 1978).
Geophysical evidence Unknown.
Evidence from other sources Precious metal lode veins occur in adjacent Proterozoic strata (Belt Supergroup) in the Wolf Creek district of the greater Helena mining district (Schmidt, 1978). Copper, Ag and Au occur in narrow veins in Greyson Shale, Spokane Formation and Empire Formation of the Belt Supergroup.
Comments The laccoliths should be checked for critical elements using trace element geochemistry methods. Underexplored Late Cretaceous magma systems may contain concealed mineral deposits. Enrichment of certain mineral commodities has been inferred from the mineral system/deposit type table (Hofstra and Kreiner, 2020).
Cover thickness and description Variable; likely ranges from 0 to 1 km.
Authors Stanley L. Korzeb, Kaleb C. Scarberry, Jay A. Gunderson, Joshua M. Rosera.
New data needs Geophysics, lidar, geochemistry, geologic mapping, trace element analysis on the laccoliths and other intrusions for critical elements. Targeted geologic mapping complemented by geochemical studies and geochronology.
Geologic mapping and modeling needs Geologic mapping.
Geophysical survey and modeling needs High resolution airborne surveys where magmatic unconformities are suspected.
Digital elevation data needs Lidar inadequate.