Central Rocky Mountains VMS

Region West, Rocky Mountains
Mineral systems
Deposit types
Critical minerals
Other minerals

Information leading to the delineation of this focus area

Basis for focus area Polygons modified from the National Assessment tract CR24 ((U.S. Geological Survey National Mineral Resource Assessment Team, 2002), previously categorized as Massive sulfide, Kuroko-type. Permissive tracts were limited to areas with documented Precambrian disseminated to massive sulfide mineralization (Sheridan and Raymond, 1984). Many of these occurrences are gahnite-bearing and associated with metavolcanic or metasediment rocks.
Identified resources Historical production of copper and zinc.
Production Sedalia deposit near Salida, Colorado produced nearly 100,000 metric tons of Cu-Zn ore.
Status Past mining.
Estimated resources Unknown.
Geologic maps Scott and others (1978), scale 1:250,000; Tweto, Steven and others (1976), scale 1:250,000.
Geophysical data Inadequate aeromagnetic and aeroradiometric coverage.
Favorable rocks and structures Precambrian metavolcanic and metasedimentary rock.
Deposits Sedalia deposit (MRDS dep_id: 10013834).
Evidence from mineral occurrences MRDS; Other occurrences documented in Sheridan and Raymond (1984).
Geochemical evidence Disseminated to massive gahnite and sphalerite as well as other base metal minerals.
Geophysical evidence No data.
Evidence from other sources No data.
Comments Gahnite (Zn-spinel) replaces sphalerite in documented deposits and occurrences. Presence of gahnite is considered to be an indicator for these deposits in the region (Sheridan and Raymond, 1984).
Cover thickness and description Variable, mix of good exposure to thick surficial cover.
Authors Allen K. Andersen, Deborah A. Briggs, Joshua M. Rosera.
New data needs Geologic mapping, lidar, geochemical sampling of ore (if available), host rock, and waste piles for critical minerals.
Geologic mapping and modeling needs None requested at this time.
Geophysical survey and modeling needs None requested at this time.
Digital elevation data needs Lidar inadequate.