Unnamed (southwest of upper Granite Creek) (ARDF #ID135) Au

Unnamed (southwest of upper Granite Creek)

Prospect, Active

Commodities and mineralogy

Main commodities	Au
Other commodities	Ag; As; Hg; Sb
Ore minerals	stibnite
Gangue minerals	calcite; quartz

Geographic location

Quadrangle map, 1:250,000-scale	ID
Quadrangle map, 1:63,360-scale	B-2
Latitude	62.3645
Longitude	-156.9514
Nearby scientific data	Find additional scientific data near this location
Location and accuracy	This prospect is at an elevation of about 1,100 feet on a flat terrace east of the head of Granite Creek. It is about 0.7 mile southwest of hill 1235, near the center of the north boundary of section 7, T. 26 N., R. 41 W., of the Seward Meridian. The location is accurate.

Geologic setting

Geologic description This prospect consists of a series of shear zones associated with thin quartz-sulfide veinlets in a light-colored granitic rock of alaskite composition and quartz-calcite veins in sandstone (Bundtzen, Miller, and Laird, 1986; Miller and Bundtzen, 1994, and Miller, Bundtzen, and Gray, 2005). The alaskite forms two dikes, each about 30 feet thick; they contain thin, 0.4- to 1-inch-thick quartz-sulfide veins on fractures and joints. The dikes strike N82-88E and are vertical. Quartz-calcite veins occur in sandstone adjacent to the dike rocks. The dikes are part of the same dike swarm that hosts gold-antimony mineralization at the Wyrick lode nearby (ID133). Grab samples of mineralization contained 500 parts per billion (ppb) silver, 48 parts per million (ppm) antimony, 560 ppb mercury, and 40 ppm arsenic. Although gold was not detected in these samples, fine gold was panned from an exploration trench (L.E. Wyrick, oral communication, 1986; Bundtzen, Miller, and Laird, 1986).
Geologic map unit	(-156.953793017581, 62.3638187243672)
Mineral deposit model	Polymetallic veins (Cox and Singer, 1986; model 22c).
Mineral deposit model number	22c
Age of mineralization	Unknown; a nearby intrusion has a 40K/40Ar age of 71.1 Ma (Miller and Bundtzen, 1994).

Production and reserves

Workings or exploration	Prospect pits were sunk on the property sometime before 1984. In 1985, L.E. Wyrick cut a 160-feet-long trench, which was sampled by Bundtzen, Miller, and Laird (1986). Battle Mountain Mining Company explored the area in the 1980s (Szumigala, 1993).
Indication of production	None

References

References Bundtzen, T.K., and Miller, M.L., 1997, Precious metals associated with Late Cretaceous-early Tertiary igneous rocks of southwestern Alaska, in Goldfarb, R.J., and Miller, L.D., eds., Mineral Deposits of Alaska: Economic Geology Monograph 9, p. 242-286. McGimsey, R.G., Miller, M.L., and Arbogast, B.F., 1988, Paper version of analytical results, and sample locality map for rock samples from the Iditarod quadrangle, Alaska: U.S. Geological Survey Open-File Report 88-421-A, 110 p., 1 sheet, scale 1:250,000. Miller, M.L., and Bundtzen, T.K., 1994, Generalized geologic map of the Iditarod quadrangle, Alaska showing potassium-argon, major oxide, trace element, fossil, paleocurrent, and archeological sample localities: U.S. Geological Survey Miscellaneous Field Studies Map MF-2219-A, 48 pages; 1 sheet, scale 1:250,000. Miller, M.L., Bundtzen, T.K., and Gray, J.E., 2005, Mineral resource assessment of the Iditarod quadrangle, west-central Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-2219-B, 2 sheets, scale 1:250,000, and 96 p. pamphlet.
Reporters	T.K. Bundtzen (Pacific Rim Geological Consulting, Inc.), M.L. Miller (U.S. Geological Survey); and C.C. Hawley (Hawley Resource Group); D.J. Grybeck (Port Ludlow, WA)
Last report date	6/5/2008