West Creek

Prospect, Inactive

Commodities and mineralogy

Main commodities Au
Ore minerals arsenopyrite; gold; marcasite; pyrite
Gangue minerals chlorite; quartz

Geographic location

Quadrangle map, 1:250,000-scale SO
Quadrangle map, 1:63,360-scale C-5
Latitude 64.679
Longitude -164.487
Nearby scientific data Find additional scientific data near this location
Location and accuracy This lode prospect is located on the south side of West Creek (SO029) at an elevation of about 400 feet; it is about 1.6 miles upstream from the confluence of West Creek and Shovel Creek (SO017). It is locality 15 of Cobb (1972, MF 445; 1978, OF 78-181), locality 8 of Asher (1969, DGGS R33), and locality 117 of Gamble (1988).

Geologic setting

Geologic description

Quartz veins in schist have been explored by an adit and 600 or 700 feet of underground workings (Smith, 1908). The quartz veins contain chlorite, small stringers and vugs of pyrite and marcasite, and arsenopyrite. Some gold and arsenopyrite is reported to be disseminated in the country rock (Smith, 1908). The adit trends about S 10 E; a zone of quartz-vein float about 50 feet wide trends S 30 W for 250 feet upslope from the adit (Asher, 1969, DGGS R33). Slickensides are present on both hanging and footwalls (Smith, 1910). A grab sample from the adit dump contained 0.04 ounces Au per ton and a composite grab sample of quartz-vein float contained 0.11 ounces Au per ton and 0.01 ounces Ag per ton (Asher, 1969, DGGS R33). Another composite grab sample of quartz on the adit dump contained 0.15 ppm Au, 5,100 ppm As, and 26 ppm Sb (Gamble, 1988). The country rock is described as chloritic schist by Smith (1910) and regional mapping indicates that it is part of a metavolcanic assemblage thought to be Ordovician in age (Till and others, 1986).
These veins are probably the same age as 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 (-164.489617815847, 64.6782548008159)
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 An adit was driven 350 feet on the main vein and a short crosscut was driven on a small stringer; there is a total of about 600 to 700 feet of underground workings (Smith, 1908). About 350 feet further west, a 300- foot-long adit was driven on similar vein.
Indication of production None

References

MRDS Number A012606

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