Unnamed (near Cheeneetnuk River)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Cu
Other commodities Mo; Zn
Ore minerals pyrite
Gangue minerals axinite; quartz

Geographic location

Quadrangle map, 1:250,000-scale MG
Quadrangle map, 1:63,360-scale A-5
Latitude 62.034
Longitude -155.228
Nearby scientific data Find additional scientific data near this location
Location and accuracy This unnamed occurrence is located on a north-south ridgeline, 3.0 kilometers NW of Cheeneetnuk River, at an elevation of 2,500 feet (762 m) in the SE1/4 sec. 36, T. 23 N., R. 33 W., of the Seward Meridian. The location corresponds to map number 136 of Gilbert (1981); his station no. 77WG236. The reporter visited the site in 1989.

Geologic setting

Geologic description

This unnamed occurrence is a pyrite-rich gossan developed in Upper Paleozoic argillite of the Mystic subterrane near a thrusted contact with an overlying, Late Devonian shallow water limestone (Gilbert, 1981; Wilson and others, 1998). The pyritic gossan parallels the thrust contact and may mark a subsidiary thrust fault zone. The argillite host appears to be thermally upgraded to hornfels by a buried intrusive system; a Tertiary granite is exposed about 5 kilometers NE of the occurrence area. Platey axinite and quartz were found in two localities in the argillite. The extent of the site is unknown. One grab sample of the pyritic material contained 290 ppm copper, 150 ppm zinc, and 7 ppm molybdenum (Gilbert, 1981).
Geologic map unit (-155.230313213552, 62.0333416727682)
Mineral deposit model Polymetallic replacement? (Cox and Singer, 1986; model 19a?).
Mineral deposit model number 19a?

Production and reserves

Workings or exploration W.G. Gilbert sampled the mineralized zone during geologic mapping for the Alaska Division of Geological and Geophysical Surveys in 1977 (Gilbert, 1981). One grab sample of the pyritic material yielded 290 ppm copper, 150 ppm zinc, and 7 ppm molybdenum.
Indication of production None
Reserve estimates None.

References