Unnamed Occurrence (ARDF - MG029; on tributary to Middle Fork of Kuskokwim River), Yukon-Koyukuk Census Area, Alaska, USAi

Regional Level Types
Unnamed Occurrence (ARDF - MG029; on tributary to Middle Fork of Kuskokwim River)	- not defined -
Yukon-Koyukuk Census Area	Census Area
Alaska	State
USA	Country

See other possible sedimentary exhalitive prospects in McGrath quadrangle (MG049, MG051, MG064, MG071, MG072, MG074).
Location: This unnamed occurrence is located near the juncture of two second order tributaries to an unnamed stream draining into Middle Fork of Kuskokwim River. It is at an elevation of 2,700 feet (823 m) in the SW1/4 sec. 34, T. 25 N., R. 28 W., of the Seward Meridian. The reporter visited the site in 1998; at station no. 98BT441.
Geology: The unnamed occurrence consists of stratiform pyrite-marcasite-galena bands parallel to sedimentary bedding in black, carbonaceous shale of the Lower Ordovician to Lower Silurian, Post River Formation, a unit of the Dillinger subterrane (Gilbert and others, 1988; Bundtzen, Harris, and Gilbert, 1997). The mineralization occurs in several outcrops at creek level that can be traced for about 75 meters; the sulfide-bearing bands are about 3 meters thick. However, individual sulfide-bearing layers are rarely more than 5 centimeters thick, and are isoclinally deformed as are the sedimentary interlayers. Microprobe analysis showed galena grains impregnated in the pyrite-rich layers. One grab sample of massive pyrite-marcasite-galena mineralization contained 2.4 grams/tonne silver, 135 ppm copper, 11.60 percent iron, 39 ppm molybdenum, 255 ppm nickel, 176 ppm lead, 168 ppm vanadium, and 208 ppm zinc.
Workings: The reporter investigated the site in 1998 (T.K. Bundtzen and G.M. Laird, written communication, 1998). One grab sample of massive pyrite-marcasite-galena mineralization contained 2.4 grams/tonne silver, 135 ppm copper, 11.60 percent iron, 39 ppm molybdenum, 255 ppm nickel, 176 ppm lead, 168 ppm vanadium, and 208 ppm zinc.
Age: Lower Paleozoic if mineralization is syngenetic.
Reserves: None.

Commodities (Major) - Ag, Cu, Pb; (Minor) - Fe, Mo, Ni, V, Zn
Development Status: No
Deposit Model: Sedimentary exhalitive lead-zinc (?) (Cox and Singer, 1986; model 31b).

Other Databases

Link to USGS - Alaska:	MG029

Other Regions, Features and Areas containing this locality

References