Unnamed (near Indian River)

Occurrence, Probably inactive

Commodities and mineralogy

Main commodities Au; Zn
Other commodities Ag; Cu; Mo; Pb
Ore minerals chalcopyrite; gold; pyrite; sphalerite; tetrahedrite

Geographic location

Quadrangle map, 1:250,000-scale HU
Quadrangle map, 1:63,360-scale A-2
Latitude 66.016
Longitude -153.7556
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is located on the west side of Indian River about 4.25 miles south-southwest of the summit of Indian Mountain. The occurrence is along a dirt road at an elevation of about 1,200 feet, about 0.4 mile north of the center of section 14, T. 7 N., R. 24 E. of the Kateel River Meridian. The location is accurate.

Geologic setting

Geologic description

This occurrence consists of disseminated pyrite and sphalerite in fresher specimens of otherwise highly altered intrusive rocks that cut Upper Jurassic(?) and Lower Cretaceous andesite (Miller and Ferrians, 1968). Both the andesite and intrusives show considerable oxidation and alteration. Samples contain anomalous lead, zinc, copper, molybdenum, gold, and silver, with up to 15 ppm silver, 1,000 ppm copper, 30 ppm molybdenum, 3,000 ppm lead, and 700 ppm zinc (Miller and Ferrians, 1968). A float sample of silicified, vuggy meta-rhyolite(?) contains disseminated pyrite and possibly tetrahedrite(?); this sample contains 8.3 ppm gold, 11.5 ppm silver, 794 ppm copper, 1,771 ppm lead, and 998 ppm zinc (Kurtak and others, 1999).
Nokleberg and others (1996) describe, without a specific location, the deposit in the Indian Mountain area as a porphyry Cu-Au system. This system, which likely includes all the individual lode occurrences within the area, consists predominately of chalcopyrite- and tourmaline-bearing intrusive breccias that are surrounded by concentric phyllic-argillic-propylitic alteration halos. A pyrite zone surrounds the intrusive rocks.
Geologic map unit (-153.758226529437, 66.0154616990036)
Mineral deposit model Porphyry Cu-Mo? (Cox and Singer, 1986; model 21a?).
Mineral deposit model number 21a?
Age of mineralization The andesite that host the deposit is Cretaceous or early Tertiary.
Alteration of deposit The intrusive rocks and andesite are oxidized and altered but no details of the alteration are described.

Production and reserves

Workings or exploration Only surface sampling.
Indication of production None

References

MRDS Number A015584

References

Bottge, R.G., 1988, Maps summarizing land availability for mineral exploration and development in western Alaska, 1986: U.S. Bureau of Mines Open-File Report 14-88, 38 quadrangle overlays.
Kurtak, J.M., Klieforth, R.F., Clark, J.M., and Maclean, E.A., 2002, Mineral investigations in the Koyukuk mining district, northern Alaska: Final Report: U.S. Bureau of Land Management Technical Report 50, v. 1 and 2, 845 p.
Reporters J.M. Britton (Anchorage)
Last report date 8/1/2002