| Quadrangle map, 1:250,000-scale | SO |
|---|---|
| Quadrangle map, 1:63,360-scale | C-4 |
| Latitude | 64.595 |
| Longitude | -163.764 |
| Nearby scientific data | Find additional scientific data near this location |
| Location and accuracy | This prospect is on the low ridge between Eldorado Creek (ARDF SO007) and Lost Creek, 1.7 miles north-northwest of Bluff. It is at an elevation of about 320 feet and is locality 20 of Cobb (1972, MF 445; 1978, OF 78-181). |
Geologic descriptionA 5.5-foot-wide quartz vein or silicified zone at a marble-schist contact carries sparse chalcopyrite, pyrite, malachite, and azurite; the central 18 inches is barren (Cathcart, 1922). Assays reported by early workers ran up to up to $80 per ton of gold (3.9 ounces per ton) (Cathcart, 1922). Bedrock in this area is part of a lower Paleozoic metasedimentary marble-schist assemblage (Herreid, 1965; Till and others, 1986). The mineralization may be mid-Cretaceous in age, the age of some lode gold deposits on southern Seward Peninsula. The southern Seward Peninsula lode gold deposits formed as a result of mid-Cretaceous metamorphism (Apodoca, 1994; Ford, 1993, Ford and Snee, 1996; Goldfarb and others, 1997) that accompanied regional extension (Miller and Hudson, 1991) and crustal melting (Hudson, 1994). This higher temperature metamorphism was superimposed on high pressure/low temperature metamorphic rocks of the region. | |
| Geologic map unit | (-163.766586001936, 64.5942635308616) |
|---|---|
| Mineral deposit model | Quartz vein or replacement at marble-schist contact; possibly low sulfide Au quartz vein (Cox and Singer, 1986; model 36a). |
| Mineral deposit model number | 36a |
| Age of mineralization | Not known - possibly mid-Cretaceous. |
| Alteration of deposit | Silicification is indicated. |
| Workings or exploration | Exploration consists of two, old shallow trenches, 2 feet deep and 20 feet long (Cathcart, 1922). |
|---|---|
| Indication of production | None |
| MRDS Number | A012585 |
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ReferencesApodoca, L.E., 1994, Genesis of lode gold deposits of the Rock Creek area, Nome mining district, Seward Peninsula, Alaska: Boulder, Colorado, University of Colorado, Ph.D. dissertation, 208 p.
Ford, R.C., 1993, Geology, geochemistry, and age of gold lodes at Bluff and Mt. Distin, Seward Peninsula, Alaska: Golden, Colorado School of Mines, Ph.D. dissertation, 302 p.
Ford, R.C., and Snee, L.W., 1996, 40Ar/39Ar thermochronology of white mica from the Nome district, Alaska--The first ages of lode sources to placer gold deposits in the Seward Peninsula: Economic Geology, v. 91, p. 213-220.
Goldfarb, R.J., Miller, L.D., Leach, D.L., and Snee, L.W, 1997, Gold deposits in metamorphic rocks in Alaska, in Goldfarb, R.J., and Miller, L.D., eds., Mineral Deposits of Alaska: Economic Geology Monograph 9, p. 151-190.
Hudson, T.L., 1994, Crustal melting events in Alaska, in Plafker, G., and Berg, H. C., eds., The Geology of Alaska: Geological Society of America, DNAG, The Geology of North America, Vol. G-1, p. 657-670.
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| Reporters | Travis L. Hudson (Applied Geology) |
| Last report date | 8/19/1999 |