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Minor podiform chromite deposit, 19 of 69 in Josephine county (in Oregon)
Sections of this page: [Geologic] - [Economic] - [Reference]
| Country | United States |
|---|---|
| State or province | Oregon |
| Geographic location: | 42°20'39"N,
123°46'20"W (-123.772222, 42.344167) |
| Geographic context: | (click for info) |
| Deposit type | minor podiform chromite |
| Model type | Minor Podiform |
| Deposit form | tabular lenses, pods, stringers |
| Deposit texture | coarse-grained massive, disseminated |
| Ore type | Metallurgical |
| Age of deposit | Middle Jurassic (164-162 Ma) |
| Age (m.y.) | 163million years |
| Area of deposit | 13832sq m |
| Ore body length | 152m |
| Ore body width | 91m |
| Mineralogy | chromite talc serpentine |
| Host rock type | harzburgite |
| Host rock length | 18000 |
| Host rock width | 6300 |
| Paleotectonic setting | suprasubduction |
| Ophiolite zone | tectonite |
| Deposits < 10km | podiform chromite, low-sulfide gold veins, placer gold, silica-carbonate Hg, mafic volcanogenic massive sulfide, volcanogenic gold, volcanogenic Hg, magmatic Ni-Co-Cu |
| Rocks within 5km | dunite serpentine harzburgite granodiorite hornblende diorite amphibolite gabbro metavolcanic rocks amphibole gneiss schist |
| Geologic map unit | -123.772222222222, 42.3441666666667 |
| Nearby scientific data | Find additional scientific data near this location |
| Discovery date | 1917 | |
|---|---|---|
| Startup date | 1917 | |
| Tonnage | 0.032429 | million metric tons |
| Ore depth | 0 | m |
| Cr2O3 grade | 46 | percent |
| Rh grade | 0.003 | g/t |
| Ir grade | 0 | g/t |
| Ru grade | 0 | g/t |
| Pd grade | 0.003 | g/t |
| Pt grade | 0 | g/t |
| Cr:Fe ratio | 2.7 |
| Comments | Largest producer in Oregon. Production to 1958 was 32,429 t. Possible ore extensions at depth, but drilling beyond a major shear zone on the northeast side of the orebody found no additional ore. Analysis 0-0.006 ppm Rh, 0.002-0.003 ppm Pd (Carlson and others, 1985). Josephine County. |
|---|---|
| References | Ramp, Len, 1961, Chromite in southwestern Oregon: Oregon Department of Geology and Mineral Industries Bulletin 52, 169 p. Ramp, Len, and Peterson, N.V., 1979, Geology and mineral resources of Josephine County, Oregon: Oregon Department of Geology and Mineral Industries Bulletin 100, 45 p. and geologic map, scale 1:500,000. Carlson, C.A., Wilson, S.A., Carlson, R.R., Bradley, L., Cornell, J., Gent, C., Gass, W., Groeneboer, H., Haffty, J., Haubert, A., Love, A., McDade, J.M., Moore, R., Riley, L., Moring, B.C., Singer, D.A., and Page, N. J, 1985, Analyses for platinum group elements in samples from podiform chromite deposits, California and Oregon: U.S. Geological Survey Open-File Report 85-442, 15 p. Evans, J.G., 1984, Structure of part of the Josephine Peridotite, northwestern California and southwestern Oregon: U.S. Geological Survey Bulletin 1546-A, p. 7-37. Harper, G.D., Saleeby, J.B., and Heizler, M., 1994, Formation and emplacement of the Josephine ophiolite and the Nevadan orogeny in the Klamath Mountains, California-Oregon--U/Pb zircon and 40Ar/39Ar geochronology: Journal of Geophysical Research, v. 99, B3, p. 4293-4321. |