Clough Occurrence, Yukon-Koyukuk Census Area, Alaska, USAi

Regional Level Types
Clough Occurrence	Occurrence
Yukon-Koyukuk Census Area	Census Area
Alaska	State
USA	Country

Similar to Rat Fork-Headwall (MG059) and Rat Fork-Base (MG058) prospects.
Location: The Clough occurrence is in a saddle that separates two northwest-trending ridgelines about 2.0 kilometers west of the north end of Smith Lake at an elevation of 4,500 feet (1,372 m) in the SW1/4 sec. 20, T. 26 N., R. 24 W., of the Seward Meridian. The reporter visited the site with Jim Clough in 1981. Note that the occurrence as shown in Bundtzen, Harris, and Gilbert (1997; map no. 10) is mislocated.
Geology: The Clough occurrence is a small but rich massive sulfide skarn zone adjacent to an altered, east-west-trending felsic (?) dike. The host rock for the skarn is argillaceous limestone of the mid-Silurian Terra Cotta Mountains Sandstone, a unit of the Dillinger subterrane (Bundtzen, Harris, and Gilbert, 1997). Principle sulfide minerals include massive pyrite and sphalerite veins up to 8 centimeters thick, and a trace of chalcopyrite in an epidote-quartz skarn. One grab sample of high grade mineralization contained 13.0 percent zinc, 0.11 percent lead, 0.50 percent copper, 26 grams/tonne silver, and 300 ppm cobalt. (Bundtzen, Kline, and Clough, 1982; Bundtzen, Harris, and Gilbert, 1997).
Workings: The Clough occurrence was found by Jim Clough of Alaska Division of Geological and Geophysical Surveys during a geologic mapping program in 1981 (Bundtzen, Kline, and Clough, 1982). One grab sample of high grade mineralization contained 13.0 percent zinc, 0.11 percent lead, 0.50 percent copper, 26 grams/tonne silver, and 300 ppm cobalt.
Alteration: None.
Reserves: None.

Commodities (Major) - Ag, Cu, Pb, Zn; (Minor) - Co
Development Status: No
Deposit Model: Low temperature lead-zinc skarn (Cox and Singer, 1986; model 18c).

Other Databases

Link to USGS - Alaska:	MG056

Other Regions, Features and Areas containing this locality

References