Commodities
PrimaryGold
SecondarySilver
Commodity typeM
Deposit
Deposit typeHydrothermal vein
Model273: Low-sulfide Au-quartz vein
Orebody formTabular, pinch and swell
Ore controlFree gold within mesothermal gold-quartz stringers
Materials
Ore mineralsGold, Pyrite, Slate
GangueQuartz
Geology
Host rockSlate,Greenstone · Salt Springs slate
StructureBear Mountains fault zone, Melones fault zone
Tectonic settingMagmatic arc
AlterationHydrothermal pyritization of greenstone
Economic & production
Development statusPast Producer
Discovery year1886
Identification
Deposit ID10310583
RegionNA
Data scoreB
Coordinates37.89457, -120.60654
References
Clark, W. B., 1970, Gold districts of California: California Divisions of Mines and Geology Bulletin 193, p. 24.Clark, W.B. and Carlson, D.W., 1956, Mines and mineral resources of El Dorado County: California Division of Mines, California Journal of Mines and Geology, v. 52, p. 413-429.Clark. W.B., and Lydon, P.A., 1962, Mines and mineral resources of Calaveras County, California: California Division of Mines and Geology County Report No. 2, p. 37, 40.Earhart, R.L., 1988, Geologic setting of gold occurrences in the Big Canyon area, El Dorado County, California: U.S. Geological Survey professional Paper 1576, 13 p.Miller, C. N., 1940, Unpublished letter report on Alto Mine for Smith Manufacturing Company, 2 p.