California · Placer County
Past Producer

Forest Hill District

Placer County, California, United States
GoldPlatinumSilverLeadIronZincCopperIndium
⌖ Show on mapUSGS source ↗
Commodities
PrimaryGold
SecondaryPlatinum, Silver
TertiaryLead, Iron, Zinc, Copper, Indium
Commodity typeM
Deposit
Deposit typeStream placer; hydrothermal vein
Model119: Placer Au-PGE273: Low-sulfide Au-quartz vein
Orebody formIrregular; Tabular, lens
Ore controlMechanical accumulation on irregular natural bedrock riffles and within river and stream channel lag gravels, bars, and point bar deposits. Deposits are often enriched downstream of eroded gold quartz veins in the bedrock channels. ? Ore shoots within mesothermal gold-bearing quartz veins.
Materials
Ore mineralsGold
GangueGravel, Quartz
Geology
Host rockSand and Gravel,Rhyolite,Tuff,Slate,Serpentinite · "Valley Springs Formation", "Calaveras Complex"
StructureMelones Fault Zone, Gillis Hill Fault Zone, Foresthill Fault, Volcano Canyon Fault, Melones Fault Zone.
Tectonic settingMagmatic arc; narrow ocean basin
AlterationNone?Negligible - none described
Economic & production
Development statusPast Producer
Discovery year1850
Identification
Deposit ID10310614
Alternate namesDardanelles, Mayflower, Paragon, Baker Divide, Smith Point, Maus, New Jersey, Jenny Lind, Independent, Baltimore, Excelsior, San Francisco, Pond?s Channel, Todd?s Valley, Peckham Hill, Gray Eagle, Georgia Hill, Yankee Jims, Small Hope, Orono, Green SpringHope, Black Hawk, Live Oak, Spring Garden, Centennial
RegionNA
Data scoreA
Coordinates39.02069, -120.81873
References
Averill, C. V., 1946, Placer mining for gold in California: California Division of Mines Bulletin 135, p. 377.Beard, J. S. and Day, H. W., 1987, The Smartville intrusive complex, Sierra Nevada, California: The core of a rifted volcanic arc: Geological Society of America Bulletin, v. 99, no. 6, p. 779-791.Brooks, E. R., 2000, Geology of a late Paleozoic island arc in the northern Sierra terrane, in Brooks, E. R. and Dida, L.T., editors, Field guide to the geology and tectonics of the northern Sierra Nevada, California Division of Mines and Geology Special Publication 122, p. 53-110.Browne, R. E., 1890, Ancient river beds of the Forest Hill Divide: California State Mining Bureau 10th Annual Report of the State Mineralogist, P. 435-465.Chandra, D. K., 1961, Geology and mineral deposits of the Colfax and Foresthill quadrangles, California: California Division of Mines Special Report 67, 50 p.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 Divisions of Mines and Geology Bulletin 193, p. 49-50.Day, H.W. and others, 1988, Metamorphism and tectonics of the northern Sierra Nevada, in Ernst, W. G., editor, Metamorphism and crustal evolution of the western United States (Rubey Volume VII): Prentice-Hall, Englewood Cliffs, New Jersey , p. 738-759.Dunn, R. L., 1888, Drift mining in California: California State Mining Bureau 8th Annual Report of the State Mineralogist, p. 736-770.Gilbert, G. K., 1917, Hydraulic mining debris in the Sierra Nevada: U.S. Geological Survey Professional Paper 105, 155 p.Hamilton, F., 1920, Placer County: California State Mining Bureau 17th Report of the State Mineralogist, p. 442-451.Hammond, J. H., 1889, The auriferous gravels of California: California State Mining Bureau 9th Report of the State Mineralogist, p. 105-138.Harwood, D.S., 1988, Tectonism and metamorphism in the northern Sierra terrane, northern California, in Ernst, W. G., editor, Metamorphism and crustal evolution of the western United States (Rubey Volume VII): Prentice-Hall, Englewood Cliffs, New Jersey, p. 764-788.Lindgren, W., 1900, Colfax folio, California: U. S. Geological Survey Atlas of the U. S., Folio 66, 10 p.Lindgren, W., 1911, The Tertiary gravels of the Sierra Nevada of California, U. S. Geological Survey Professional Paper 73, 226 pp.Logan, C. A., 1927, Placer County: California Division of Mines 23rd Report of the State Mineralogist, p. 235-279.Logan. C. A., 1936, Gold mines of Placer County: California Division of Mines 32nd Report of the State Mineralogist, p. 7-96.Logan, C. A., 1948, History of mining and milling methods in California, in Jenkins, O.P. and others, editors, Geologic guidebook along highway 49 - Sierran gold belt - The Mother Lode Country: California Division of Mines Bulletin 141, p. 31-34.Merwin, R. W., 1968, Gold resources in the Tertiary gravels of California: U.S. Bureau of Mines Technical Progress Report 3, 14 p.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.Wagner, D. L. and others, 1987, Geologic map of the Sacramento Quadrangle: California Division of Mines and Geology Regional Map Series Map No. 1A, scale 1:250,000.Waring, C. A., 1917, Placer County: California State Mining Bureau 15th Report of the State Mineralogist, p. 309-399.