Commodities
PrimaryGold
SecondaryPlatinum, Silver
Commodity typeM
Deposit
Deposit typeStream placer
Model119: Placer Au-PGE
Orebody formIrregular
Ore controlMechanical accumulation on irregular bedrock riffles and within river and stream channel lag gravels, bars, and point bar deposits
Materials
Ore mineralsGold, Quartz, Magnetite, Ilmenite, Zircon, Pyrite, Amphibole, Epidote, Chlorite, Siderite
Geology
Host rockSand and Gravel
StructureMelones Fault Zone, Melones Fault Zone, Foresthill Fault
Tectonic settingMagmatic arc
Economic & production
Development statusPast Producer
Discovery year1850
Identification
Deposit ID10310582
RegionNA
Data scoreB
Coordinates39.33669, -120.75893
References
Clark, L. D., 1960, Foothills fault system, western Sierra Nevada, California: Geological Society of America Bulletin, v. 71, p. 483-496.Clark, W.B., 1966, Gold, in Mineral resources of California: California Division of Mines and Geology Bulletin 191, p. 179-185.Clark, W.B., 1970, Gold districts of California: California Division of Mines and Geology Bulletin 193, p. 128.Jarman, A, 1927, Omega Mine: California State Mining Bureau Report 23, p. 112-113.Lindgren, W., 1900, Colfax folio: U.S. Geological Survey Atlas of the U.S., Folio 66, 10 p.Lindgren, W., 1911, Tertiary gravels of the Sierra Nevada: U.S. Geological Survey Professional Paper 73, p. 139-141.MacBoyle, E., 1919, Nevada County, Washington Mining District: California State Mining Bureau Report 16, p. 59-63.Saucedo, G. J. and Wagner, D. L., 1992, Geologic map of the Chico Quadrangle: California Division of Mines and Geology Regional Map Series Map No. 7A, scale 1:250,000.Yeend, W.E., 1974, Gold-bearing gravel of the ancestral Yuba River, Sierra Nevada, California: U.S. Geological Survey Professional Paper 772, 44 p.Additional information on the Alpha-Omega mines is contained in File No. 339-5934 (CGS Mineral Resources Files, Sacramento).