Unnamed (southeast Nakchamik Island)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Cu
Ore minerals chalcopyrite; pyrite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale SW
Quadrangle map, 1:63,360-scale B-6
Latitude 56.32
Longitude -157.82
Nearby scientific data Find additional scientific data near this location
Location and accuracy This site is located near the southeast coast of Nakchamik Island (MacKevett and Holloway, 1977, locality 1). The island is approximately 10 miles south of Cape Kumliun in Chignik Bay. Site location is accurate to within 1 mile.

Geologic setting

Geologic description

This site is marked by a color anomaly which coincides with a dacite plug dome that has intruded volcanics of the Oligocene and Eocene Meshik Formation (Detterman and others, 1981; Cox and others, 1981). This mineral occurrence has been described as a porphyry copper deposit consisting of disseminated sulfides in strongly altered intrusive and surrounding volcanic rocks (MacKevett and Holloway, 1977). No mention is made of ore or gangue minerals present.
Geologic map unit (-157.822037228436, 56.3192330703889)
Mineral deposit model Porphyry copper (Cox and Singer, 1986, model 17)
Mineral deposit model number 17
Age of mineralization Tertiary.
Alteration of deposit The alteration is unknown but probably includes propylitic and sericitic types.

Production and reserves

Workings or exploration Apparently this occurrence has had post-1950 activity (U.S. Bureau of Mines, 1973).
Indication of production None

Additional comments

This site is located on land selected by the Koniag Native Corporation.