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Minor podiform chromite deposit, 9 of 13 in San Luis Obispo county (in California)

Sections of this page: [Geologic] - [Economic] - [Reference]

Geologic Information
Other namesBiaggini
CountryUnited States
State or provinceCalifornia
Geographic location:35°24'14"N, 120°44'38"W
(-120.743889, 35.403889)
Geographic context: (click for info)
Deposit typeminor podiform chromite
Model typeBanded Podiform
Deposit formirregular pods, stringers
Deposit texturemassive, disseminated
Ore typeMetallurgical
Age of depositMiddle Jurassic (163.3±1.1 Ma, U-Pb apatite-feldspar isochron in gabbro)
Age (m.y.)163million years
Host rock typeserpentinized dunite
Host rock length20000
Host rock width4250
Paleotectonic settingsuprasubduction
Ophiolite zonetransition
Deposits < 10kmpodiform chromite
Rocks within 5kmserpentine
Geologic map unit-120.743888888889, 35.4038888888889
Nearby scientific dataFind additional scientific data near this location
Economic Information
Tonnage0.005414million metric tons
Ore depth0m
Cr2O3 grade39percent
Fe %13.81percent
Cr:Fe ratio2.55
Reference information
CommentsProduction is incomplete. In 1943-1944, 414 t of ore averaging 39% Cr2O3 was produced. Reported production of 2,143 t of mostly concentrates prior to 1943 apparently includes production from other mines. Estimated 5,414 t total production. 37% chromite, 51.45% Cr2O3. San Luis Obispo County.
Choi, S.H., Shervais, J.W., and Mukasa, S.B., 2008, Supra-subduction and abyssal mantle peridotites of the Coast Range ophiolite, California: Contributions to Mineralogy and Petrology, v. 156, p. 551-576.
Walker, G.W., and Griggs, A.B., 1953, Chromite deposits of the southern Coast Ranges of California, in Geological investigations of chromite in California, Part 2--Coast Ranges: California Division of Mines Bulletin 134, pt. 2, ch. 2, 88 p.
Jennings, C.W., 1958, Geologic map of California, San Luis Obispo sheet: California Division of Mines and Geology, scale 1:250,000.
Hopson, C.A., Mattinson, J.M., Pessagno, E.A., Jr., and Luyendyk, B.P., 2008, California Coast Range ophiolite--Composite Middle and Late Jurassic oceanic lithosphere: Geological Society of America Special Paper 438, p. 1-101.
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