| Main commodities | Au; Cu |
|---|---|
| Ore minerals | arsenopyrite; chalcopyrite; gold; pyrite; pyrrhotite |
| Gangue minerals | quartz |
| Quadrangle map, 1:250,000-scale | SO |
|---|---|
| Quadrangle map, 1:63,360-scale | C-5 |
| Latitude | 64.661 |
| Longitude | -164.251 |
| Nearby scientific data | Find additional scientific data near this location |
| Location and accuracy | This prospect is about 3/4 mile northwest of the Big Hurrah mine on the ridge east of Trilby Creek. It is at about 350 feet elevation and 1/2 mile north of big Hurrah Creek. It is locality 18 of Cobb (1972, MF 445; 1978, OF 78-181). |
Geologic descriptionQuartz vein in graphitic schist with pyrite, pyrrhotite, arsenopyrite, chalcopyrite, and free gold. Three shafts and several trenches were caved in 1920 (Cathcart, 1922). The alignment of the trenches may indicate a N to NE strike, and dump samples contained up to 0.17 ounces Au per ton and 0.04 percent Cu (Asher, 1969, DGGS R33). The country rock is part of a lower Paleozoic metasedimentary assemblage that includes a distinctive black, very fine-grained, graphitic schist (Sainsbury and others, 1972, OFR 511; Till and others, 1986). This quartz vein may be similar in age to some other gold-quartz veins of 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 | (-164.253606162413, 64.660258434355) |
|---|---|
| Mineral deposit model | Gold-quartz vein in metamorphic rocks; low sulfide-Au quartz vein (Cox and Singer, 1986; model 36a). |
| Mineral deposit model number | 36a |
| Age of mineralization | Cretaceous? |
| Alteration of deposit | Silicification. |
| Workings or exploration | There were about a dozen trenches, 5 to 30 feet long and 3 to 4 feet deep, and three shafts that were caved and water filled in 1920. |
|---|---|
| Indication of production | None |
| MRDS Number | A012591 |
|---|---|
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 |