RC Occurrence, Tok Mining District, Southeast Fairbanks Census Area, Alaska, USAi

Regional Level Types
RC Occurrence	Occurrence
Tok Mining District	Mining District
Southeast Fairbanks Census Area	Census Area
Alaska	State
USA	Country

Unpublished data cited is available for viewing by contacting Grayd Resources Inc. in Vancouver, B. C., Canada (www.grayd.com), or Northern Associates Inc. in Fairbanks, Alaska.
Location: The RC occurrence is at an elevation of about 7,000 feet, 3.4 miles north-northwest of Mount Kimball and south of the head of Rock Candy Creek. The occurrence is in the NW1/4NE1/4 section 10, T. 19 S., R. 16 E., Fairbanks Meridian.
Geology: The RC massive sulfide occurrence consists of pyrite bands with distinctive sphalerite-galena banding and chalcopyrite along fractures. The massive sulfide exposures vary from several inches to 5 feet in thickness. Outcrops are limited; extensive boulder trains of massive sulfides extend downslope and along the trend of the outcrop. Hydrothermal quartz-pyrite-arsenopyrite-stibnite veins locally cut blocks of massive sulfide float. Three veins crop out, each as much as 5 inches in thickness. They contain pyrite, arsenopyrite, galena, sphalerite, and stibnite. The gangue is quartz and carbonate with patches of adularia (?) in selvages as much as 2 inches thick. The veins generally crosscut both bedding and schistosity but are locally parallel to them. The average grade of the massive sulfide mineralization is 0.42 percent copper, 3.97 percent lead, 5.51 percent zinc, 57.2 parts per million silver, and traces of gold (Lange and others, 1993). Exploration of the massive sulfide mineralization soon focused on the higher grade polymetallic veins (J.K. Muntzert and others, unpublished Resource Associates of Alaska, Inc. report, 1977). The rocks in the area consist of a complex sequence of volcaniclastic sedimentary rocks, predominantly of intermediate composition. Felsic and mafic metavolcanic and metasedimentary rocks also occur; they include calcareous schist, dolomite, limestone, siltstone, quartzite, and black carbonaceous schist. The rock units are typically thin bedded, strike northwest, and dip moderately southwest. The schistosity and folds are generally parallel to the regional strike, with local exceptions (R.A. Blakestad and others, unpublished Resource Associates of Alaska, Inc. report, 1976).
Workings: Four core holes totaling 1,116 feet were drilled in 1977, 1978, and 1980 on the RC occurrence (S.S. Dashevsky, written communication, 2003). Exploration of the massive sulfide mineralization soon focused on the higher grade polymetallic veins (J.K. Muntzert and others, unpublished Resource Associates of Alaska, Inc. report, 1977).
Age: Devonian, on the basis of the age of the host rock, which is in the Jarvis Creek Glacier subterrane (Nokleberg and others, 1992).

Commodities (Major) - Ag, Cu, Pb, Zn
Development Status: None
Deposit Model: Polymetallic veins and Kuroko massive sulfide (Cox and Singer, 1986; model 22c,

Other Databases

Link to USGS - Alaska:	MH254

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References