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Minor podiform chromite deposit, 28 of 30 in Placer county (in California)
Sections of this page: [Geologic] - [Economic] - [Reference]
| Country | United States |
|---|---|
| State or province | California |
| Geographic location: | 38°58'N,
120°55'16"W (-120.921111, 38.966667) |
| Geographic context: | (click for info) |
| Deposit type | minor podiform chromite |
| Model type | Minor Podiform |
| Deposit form | small bunches, stringers |
| Deposit texture | fine-grained disseminated |
| Ore type | Unknown |
| Age of deposit | Pennsylvanian (304-311 Ma U-Pb zircon from plagiogranite) |
| Age (m.y.) | 311million years |
| Mineralogy | chromite magnetite |
| Host rock type | serpentine |
| Host rock length | 3200 |
| Host rock width | 2600 |
| Paleotectonic setting | off-ridge |
| Ophiolite zone | tectonite |
| Deposits < 10km | podiform chromite |
| Rocks within 5km | serpentine amphibolite schist basalt basalt tuff andesite andesite tuff andesite breccia slate graywacke conglomerate mudstone quartzite chert gabbro amphibolite schist mudflow breccia rhyolite tuff sandstone |
| Geologic map unit | -120.921111111111, 38.9666666666667 |
| Nearby scientific data | Find additional scientific data near this location |
| Discovery date | 1917 | |
|---|---|---|
| Startup date | 1917 | |
| Tonnage | 9e-06 | million metric tons |
| Mine depth | 3.7 | m |
| Ore depth | 0 | m |
| Cr2O3 grade | 32.3 | percent |
| Comments | Central Belt. Placer County. |
|---|---|
| References | Rynearson, G.A., 1951, Chromite deposits in the northern Sierra Nevada, California (Placer, Nevada, Sierra, Yuba, Butte, and Plumas counties), in Geological investigations of chromite in California, Part 3--Sierra Nevada: California Division of Mines Bulletin 134, pt. 3, ch. 5, 321 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. Saleeby, J.B., 1982, Polygenetic ophiolite belt of the California Sierra Nevada--Geochronological and tectonostratigraphic development: Journal of Geophysical Research, v. 87, no. B3, p. 1803-1824. |