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Minor podiform chromite deposit, 22 of 29 in El Dorado county (in California)
Sections of this page: [Geologic] - [Economic] - [Reference]
| Country | United States |
|---|---|
| State or province | California |
| Geographic location: | 38°49'45"N,
120°52'47"W (-120.879722, 38.829167) |
| Geographic context: | (click for info) |
| Deposit type | minor podiform chromite |
| Model type | Minor Podiform |
| Deposit form | small stringers |
| Deposit texture | medium-grained massive, disseminated |
| Ore type | Unknown |
| Age of deposit | pre-Early Devonian-Jurassic (388±17 Ma U-Pb zircon from felsic igneous rocks; 174 Ma K-Ar white mica from blueschists) |
| Age (m.y.) | 388million years |
| Area of deposit | 27.6sq m |
| Ore body length | 6m |
| Ore body width | 4.6m |
| Mineralogy | chromite |
| Host rock type | serpentinized dunite |
| Host rock length | 6500 |
| Host rock width | 3500 |
| Paleotectonic setting | suprasubduction |
| Ophiolite zone | tectonite |
| Deposits < 10km | podiform chromite |
| Rocks within 5km | serpentinized dunite harzburgite serpentine granodiorite diorite basalt flow basalt tuff gabbro greenstone andesite flow andesite tuff andesite breccia rhyolite flow rhyolite tuff slate graywacke conglomerate |
| Geologic map unit | -120.879722222222, 38.8291666666667 |
| Nearby scientific data | Find additional scientific data near this location |
| Discovery date | 1916 | |
|---|---|---|
| Startup date | 1916 | |
| Tonnage | 3e-05 | million metric tons |
| Mine depth | 3 | m |
| Ore depth | 0 | m |
| Cr2O3 grade | 35 | percent |
| Comments | Location uncertain, but is 244 m south of Simon North workings. Production of 30 t of ore @ 35% Cr2O3 is estimated from pit size. Feather River Belt. El Dorado County. |
|---|---|
| References | Mayfield, J.D., and Day, H.W., 2000, Ultramafic rocks in the Feather River Belt, northern Sierra Nevada, California, in Brooks, E.R., and Dida, L.T., eds., Field guide to the geology and tectonics of the northern Sierra Nevada, National Association of Geoscience Teachers Far-Western Section Fall Conference 2000: California Division of Mines and Geology Special Publication 122, p. 1-15. Cater, F.W., Jr., Rynearson, G.A., and Dow, D.H., 1951, Chromite deposits of El Dorado County, California, in Geological investigations of chromite in California, Part 3--Sierra Nevada: California Division of Mines Bulletin 134, pt. 3, ch. 4, 167 p. Wagner, D.L., Jennings, C.W., Bedrossian, T.L., and Bortugno, E.J., 1981, Geologic map of the Sacramento quadrangle: California Division of Mines and Geology Regional Geologic Map Series Map no. 1A, scale 1:250,000. Ehrenberg, S.N., 1975, Feather River ultramafic body, northern Sierra Nevada, California: Geological Society of America Bulletin, v. 86, p. 1235-1243. |