Unnamed Prospect (ARDF - SM053; north end of Buckstock Mountains), Aniak Mining District, Bethel Census Area, Alaska, USAi

Regional Level Types
Unnamed Prospect (ARDF - SM053; north end of Buckstock Mountains)	- not defined -
Aniak Mining District	Mining District
Bethel Census Area	Census Area
Alaska	State
USA	Country

Location: This prospect is on hill 2008 at the head of the northern tributary to Gold Run in the northern Buckstock Mountains. The occurrence is near the center of the SW1/4 sec. 5, T. 15 N., R. 51 W., of the Seward Meridian. The location is accurate.
Geology: This prospect consists of two quartz-sulfide veins that strike N75-80W across a knob of hornfels of the Upper Cretaceous Kuskokwim Group; the hornfels is cut by N70E-striking felsic dikes of the Cretaceous Buckstock Mountains intrusive complex (Cady and others, 1955). A younger dike that strikes north-south also cuts hornfels on the ridge. The Buckstock Mountains pluton has a U-Pb age of 59.2 Ma (Miller and others, 2002). The mineralized quartz veins cut both the hornfels and the dikes. The dikes are argillized and the hornfels near the dikes are intensely altered to tourmaline, quartz, and ferricrete. The two mineralized quartz veins each average about 12 to 20 inches thick and can be traced for about 280 feet before disappearing into talus on both sides of the knob. Sulfides, which make up 1 to 2 percent of the quartz veins, include arsenopyrite, bornite, chalcopyrite, and traces of sphalerite. Yellow scheelite grains were identified in hand specimens The sulfides are usually associated with quartz that forms coxcomb textures. Six grab samples of the quartz-sulfide veins contained 187 parts per billion (ppb) gold, 72.7 parts per million (ppm) silver, 1,410 ppm copper, 149 ppm bismuth, 1,060 ppm lead, 419 ppm zinc, 495 ppm arsenic, 6.0 ppm cadmium, and 419 ppm tungsten (M.L. Miller and T.K. Bundtzen, unpublished analytical data, 1992, 1999).
Workings: This prospect was sampled during a joint Alaska Division of Geological and Geophysical Surveys and U.S. Geological Survey investigation in 1992.
Age: Unknown. Miller and others (2002) report a U-Pb age of 59.2 Ma for the Buckstock pluton that is present here as felsic dikes.
Alteration: Strong argillic alteration in dikes; tourmaline impregnations in hornfels.

Commodities (Major) - Ag, Au, Cu; (Minor) - As, Bi, Cd, Pb, W, Zn
Development Status: None
Deposit Model: Polymetallic vein (Cox and Singer, 1986; model 22c).

Other Databases

Link to USGS - Alaska:	SM053

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References