Unnamed (lower Ptarmigan Creek)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Cu
Ore minerals chalcopyrite; pyrite

Geographic location

Quadrangle map, 1:250,000-scale MC
Quadrangle map, 1:63,360-scale D-1
Latitude 61.9425
Longitude -141.0405
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is in outcrops on a bench on the east side of lower Ptarmigan Creek. It is at an elevation of about 3,500 feet and 9,500 feet south of Beaver Creek. The site is about 1,600 feet east-northeast of the center of section 20, T. 2 N., R. 24 E. of the Copper River Meridian. This is locality 185 of MacKevett (1976). It is probably accurate to within 1,000 feet.

Geologic setting

Geologic description

This occurrence consists of pyrite and minor chalcopyrite that coat fracture surfaces in altered Tertiary gabbro (Knaebel, 1970; MacKevett, 1978). The alteration includes abundant replacement by sericitized plagioclase and chlorite. The closely-spaced fractures trend N 70-80 E and are commonly slickensided. The occurrence is near the faulted north contact of gabbro with Jurassic or Cretaceous siliciclastic rocks (MacKevett, 1978).
Geologic map unit (-141.042611796484, 61.9421716854915)
Mineral deposit model Pyrite and chalcopyrite along fractures in gabbro
Age of mineralization The gabbro host rock is late Tertiary.
Alteration of deposit Alteration in the gabbro includes abundant replacement by sericitized plagioclase and chlorite.

Production and reserves

Indication of production None

Additional comments

The locality is in the Wrangell-Saint Elias National Park and Preserve.