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
GangueQuartz, Magnetite, Ilmenite, Zircon, Pyrite, Amphibole, Epidote, Chlorite, Siderite
Geology
Host rockSand and Gravel
StructureRamshorn Fault, Big Bend-Wolf Creek Fault, Ramshorn Fault, Melones Fault Zone
Tectonic settingMagmatic arc
Economic & production
Development statusPast Producer
Discovery year1851
Identification
Deposit ID10310656
RegionNA
Data scoreA
Coordinates39.37129, -120.91353
References
Clark, W.B., 1970, Gold districts of California: California Division of Mines and Geology Bulletin 193, p. 101.Hobson, J.B. and Wiltsee, E.A., 1893, North Bloomfield mining district; California State Mining Bureau Report 11, p. 311-312.Irelan, W., Jr., 1888, North Bloomfield mine: California State Mining Bureau Report 8, p. 454-459.Jarman, A, 1927, An investigation of the feasibility of any plan or plans whereby hydraulic mining operations can be resumed in this state: California State Mining Bureau Report 23, p. 103-111.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: North Bloomfield mining district: California State Mining Bureau Report 16, p. 45-51.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.