Unnamed (Big Hurrah Creek)

Prospect, Probably inactive

Commodities and mineralogy

Main commodities Au; Cu
Ore minerals arsenopyrite; chalcopyrite; gold; pyrite; pyrrhotite
Gangue minerals quartz

Geographic location

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 setting

Geologic description

Quartz 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.

Production and reserves

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

References

MRDS Number A012591

References

Apodoca, 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.
Reporters Travis L. Hudson (Applied Geology)
Last report date 8/19/1999