Judith Mountains

Region West, Northwest
States
Mineral systems
Deposit types
Commodities
Other minerals

Information leading to the delineation of this focus area

Basis for focus area Hall (1977) noted that the intense potassium metasomatism and late calcite-fluorite-quartz veins present in the bottom 400 meters of a 700-meter core hole from the Red Mountain area is indicative of a carbonatite body at depth (Kohrt, 1991). Known deposit types are metallic-lode deposits including intrusive complexes, carbonate replacements, veins in igneous rocks, skarns, and disseminated deposits hosted by intrusives. Historical production was from gold-silver telluride quartz veins that are associated with occurrences of vanadium and fluorite. This focus area is listed as potential Magmatic REE as well as Alkalic porphyry mineral systems.
Identified resources Identified resources for gold. Historical production of gold, silver, and base metals.
Production Unknown.
Status Past mining.
Estimated resources Gies mine (1990): Demonstrated reserves of 43,545 metric tons of ore with a grade of 9.3g/metric ton Au.
Geologic maps Goddard (1988), scale 1:31,680.
Geophysical data Inadequate aeromagnetic and aeroradiometric coverage.
Favorable rocks and structures Alkali-calcic suite: quartz monzonite, monzonite, quartz diorite, diorite, syenite and rhyolite. Alkaline suite: alkali gabbro, syenite, ijolitic rocks, gray tinguaite, green tinguaite, carbonatite (?) with associated fenite and alkali granite.
Deposits Gies mine (MRDS dep_id: 10196569), Spotted Horse mine (MRDS dep_id: 10071386), Maginnis mine (MRDS dep_id: 10071340).
Evidence from mineral occurrences MRDS.
Geochemical evidence Late veins containing calcite, fluorite, quartz, barite, rutile, aegirine and scapolite were present in the bottom 400 meters of a 700-meter core hole in the Red Mountain area.
Geophysical evidence Unknown.
Evidence from other sources None.
Comments Younger alkalic rock types, fenitization, and late calcite-fluorite-quartz veins are common in alkaline complexes that host REE-rich carbonatites.
Cover thickness and description Late veins containing calcite, fluorite, quartz, barite, rutile, aegirine and scapolite noted in drill core. Surface exposure of other rock types.
Authors Allen K. Andersen, Stanley L. Korzeb, Kaleb C. Scarberry, Jay A. Gunderson, Joshua M. Rosera.
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 in progress only over western third; rest has no lidar coverage.