| Previous record: 58 | Next record: 60 |
Minor podiform chromite deposit, 4 of 20 in Calaveras county (in California)
Sections of this page: [Geologic] - [Economic] - [Reference]
| Other names | Main High-Grade |
|---|---|
| Country | United States |
| State or province | California |
| Geographic location: | 37°57'23"N,
120°33'36"W (-120.56, 37.956389) |
| Geographic context: | (click for info) |
| Deposit type | minor podiform chromite |
| Model type | Minor Podiform |
| Deposit form | pods |
| Deposit texture | massive, disseminated |
| Ore type | Metallurgical |
| Age of deposit | Permian (280±3 m.y. 206Pb/238U, 282±3 m.y. 207Pb/235U) |
| Age (m.y.) | 281million years |
| Mineralogy | chromite |
| Host rock type | dunite |
| Host rock length | 30000 |
| Host rock width | 6000 |
| Ophiolite zone | tectonite |
| Deposits < 10km | podiform chromite |
| Rocks within 5km | serpentine dunite harzburgite pyroxenite slate phyllite argillite conglomerate graywacke chert pillow basalt basalt pyroclastics quartz diorite granodiorite |
| Geologic map unit | -120.56, 37.9563888888889 |
| Nearby scientific data | Find additional scientific data near this location |
| Tonnage | 0.000152 | million metric tons |
|---|---|---|
| Mine depth | 4.6 | m |
| Ore depth | 0 | m |
| Cr2O3 grade | 46 | percent |
| Comments | Estimated production based on size of underground workings using 1 m ore widths. Tuolumne ophiolitic melange. Calaveras County. |
|---|---|
| References | Rogers, T.H., 1966, Geologic map of California, San Jose sheet: California Division of Mines and Geology, scale 1:250,000. Cater, F.W., Jr., 1948, Chromite deposits of Calaveras and Amador counties, California, in Geological investigations of chromite in California, Part 3--Sierra Nevada: California Division of Mines Bulletin 134, pt. 3, ch. 2, 60 p. 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. |