Central Colorado epithermal Au-Ag

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 Permissive tract CR26 for epithermal vein, quartz-adularia type: Polygons extracted and merged from the 1995 National Assessment (U.S. Geological Survey National Mineral Resource Assessment Team, 2002). The CR26 polygon was edited generally based on the surficial outcrop of volcanic rocks to the west of the San Luis Valley as presented in Tweto (1979). The small areas to the north are based on CR26.
Identified resources Historical mining of copper, fluorite, gold, lead, silver, and zinc.
Production Production was mainly Cu, Au, Pb, Ag, and Zn. For production estimates and commodities, see references associated mining districts located within this area (listed under Deposits).
Status Past mining.
Estimated resources Unknown due the numerous mining districts and large nature of this area.
Geologic maps Pearl (1980), scale 1:500,000; Johnson (1969), scale 1:250,000; Steven and others (1974), scale 1:250,000; there are many 1:24,000 scale quadrangles mapped in this area.
Geophysical data Inadequate aeromagnetic and aeroradiometric coverage.
Favorable rocks and structures Volcanic fields of felsic to intermediate composition such as the Flat Tops, Thirtynine Mile, and San Juan volcanic fields.
Deposits Creede, Lake City, Crystal Hill, Equity, Bondholder, San Luis Hills, Platoro, Stunner, Axtell, Crater Creek, Lincoln Gulch, Independence. Mining districts include the following: In the west: Burrows Park, Carson, Galena, Lake, Park, Sherman, Red Mountain, Imogene Basin, Upper Uncompahgre, Camp Bird, Sneffels, Sentinel, Paquin, Uncompahgre, Ouray, Putnam, Ice Lake Basin, Cement Creek, Animas, Eureka, Poughkeepsie, Animas Forks, Mineral Point, Ophir, Iron Springs, Telluride, and Upper San Miguel. In the central area: Creede, King Solomon, Sunnyside, Spar City/Royal Arch, Wagon Wheel Gap, Bondholder, Sky City Mine, and Embargo. In the northeast: Poncha, Manitou, Bonanza, Kerber Creek, Findlay Gulch, Ford Creek, Tracy Canyon, Crystal Hill, and Iron Mountain. In the south: Platoro, Decatur (Stunner-Gilmore), Jasper, Summitville, and Crater.
Evidence from mineral occurrences MRDS (list more than 30 prospects and occurrences for As, Bi, Te, Sb, and others commodities).
Geochemical evidence Unknown.
Geophysical evidence Unknown.
Evidence from other sources Unknown.
Comments Area includes possible examples of partially eroded hot-spring deposits: Golden Wonder (Kalliokoski and Rehn, 1987), San Luis gold deposit, prospects along the west side of the Sangre de Cristo Mountains, and Poncha Hot Springs, where one sample of fluorspar ore contained 100 ppb Au (A. Wallace, USGS, unpub. data, 1993).
Cover thickness and description Volcanic cover.
Authors Jane M. Hammarstrom.
New data needs Compilation geologic maps, lidar, geochemical sampling to confirm the presence of critical minerals in ore (if available), host rock, and waste rock.
Geologic mapping and modeling needs Need 1:24,000 scale geologic mapping to around 1:100,000 scale geologic mapping. Alternatively, compilation of existing 1:250,000 scale geologic maps (for example, Durango and Trinidad) from this area.
Geophysical survey and modeling needs None requested at this time.
Digital elevation data needs Lidar has been acquired for the San Luis valley but not for the western areas of the focus area in Saguache, Rio Grand and Conejos counties.