Unnamed (northwest of the terminus of the Hayes Glacier)

Prospect, Undetermined

Commodities and mineralogy

Main commodities Ag; As; Au; Cu; Pb; Sn; Zn
Ore minerals chalcopyrite; galena; pyrite; pyrrhotite; sphalerite

Geographic location

Quadrangle map, 1:250,000-scale MH
Quadrangle map, 1:63,360-scale C-6
Latitude 63.69
Longitude -146.6593
Nearby scientific data Find additional scientific data near this location
Location and accuracy This prospect is east of the lower portion of the west lobe of the Hayes Glacier. It is 5.2 miles north-northwest of Mount Hayes and about 0.3 mile north of the center of section 19, T. 14 S., R. 6 E.

Geologic setting

Geologic description

The rocks in the area are derived from Devonian felsic to intermediate volcanic rocks, mainly andesite, dacite, and quartz keratophyre flows and tuffs, and from Devonian or older shale, marl, and marble (Nokleberg and others, 1992 [MF-1996-D]; Nokleberg and others, 1992 [OFR 92-594]; Bittenbender and others, 2007). The rocks were metamorphosed and intensely deformed into chlorite schist, limestone, and greenstone that were first metamorphosed to lower amphibolite facies in the Early Cretaceous and then retrograded to lower greenschist grade in the mid-Cretaceous.
Resource Associates of Alaska was active in the area in 1970s but they deeded their claims to Cook Inlet Region Incorporated in 1980 (Bittenbender and others, 2007). The prospect was examined and sampled by the U.S. Geological Survey in about 1990 (Nokleberg and others, 1991), by the American Copper and Nickel Company in 1993, and by the Bureau of Land Management in the early 2000s. There are no workings on the prospect.
This prospect is part of a belt of massive sulfide deposits that is about 8 miles long and as much as one-third of a mile wide (Nokleberg and others, 1991; Lange and others, 1993).. Deposits in the belt consist of massive sulfide lenses, pods, and disseminations of pyrrhotite and pyrite, and less abundant galena, sphalerite, and chalcopyrite. Individual lenses and pods are as much as 3 feet thick.
Samples collected here during reconnaissance sampling by the U.S. Geological Survey in the 1980s contained as much as 0.72 percent lead, 0.69 percent zinc, 0.5 percent arsenic, and 0.11 percent copper (Nokleberg and others, 1991). Bittenbender and others (2007) identified zones of thin, massive sulfide pods, lenses, and stringers in tightly folded quartz-mica and quartz-chlorite schist from about 4,900 to 5,300 feet elevation. The zones generally are less than 1 foot thick, may structurally thicken to 2 feet, and are 3 to 4 feet in length. The sulfides are mainly pyrrhotite with small amounts of chalcopyrite, pyrite, and galena. Their samples contained up to 685 parts per billion gold, 13.7 parts per million (ppm) silver, 4,660 ppm copper, 1,350 ppm lead, and 1,035 ppm zinc.
Geologic map unit (-146.661593796957, 63.6895823138775)
Mineral deposit model Kuroko massive sulfide (Cox and Singer, 1986; model 28a).
Mineral deposit model number 28a
Age of mineralization Probably Devonian, the pre-metamorphic age of the host rocks.
Alteration of deposit Not specifically noted.

Production and reserves

Workings or exploration Resource Associates of Alaska was active in the area in 1970s but they deeded their claims to Cook Inlet Region Incorporated (Bittenbender and others, 2007). The prospect was examined and sampled by the U.S. Geological Survey in about 1990 (Nokleberg and others, 1991), by the American Copper and Nickel Company in 1993, and by the Bureau of Land Management in the early 2000s. There are no workings on the prospect.
Indication of production None
Reserve estimates None.
Production notes None.

References

References

Bittenbender, P.E., Bean, K.W., Kurtak, J.M., and Deininger, James Jr., 2007, Mineral assessment of the Delta River Mining District area, east-central, Alaska: U.S. Bureau of Land Management, Alaska Technical Report 57, 675 p.
Lange, I. M., Nokleberg, W.J., Newkirk, S. R., Aleinikoff, J.N., Church, S.E., and Krouse, R.H., 1993, Devonian volcanogenic massive sulfide deposits and occurrences, southern Yukon-Tanana terrane, eastern Alaska Range, Alaska: Economic Geology, v. 88, p. 344-376.
Reporters W.T. Ellis (Alaska Earth Sciences), C.C. Hawley (Hawley Resource Group), and W.J. Nokleberg (USGS); D.J. Grybeck (Contractor, USGS)
Last report date 5/13/2012