Unnamed (east of toe of Gakona Glacier)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Cu
Ore minerals chalcopyrite; copper; pyrite

Geographic location

Quadrangle map, 1:250,000-scale MH
Quadrangle map, 1:63,360-scale A-3
Latitude 63.2005
Longitude -145.0938
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is at an elevation of about 5,250 feet, about 2 miles east of the terminus of the Gakona Glacier and 1.0 mile north-northeast of VABM 5206 'Ona'. It is about 0.6 mile northeast of the center of section 8, T. 20 S., R. 14 E.

Geologic setting

Geologic description

Rose (1965) mapped the rocks in the area as argillite intruded by small diorite plutons. Nokleberg and others (1991; 1992 [MF]; 1992 [Open-File] considered that the argillite is part of the Pennsylvanian and Permian, Slana Spur Formation and that the diorite is Triassic. Bittenbender and others (2007) identified isolated outcrops of bleached white marble and mineralized skarn with chalcopyrite and pyrite here; they consider the diorite to be Cretaceous. The marble and skarn is copper stained near the contact with the diorite and their samples contained up to 2,020 parts per million copper and 18 parts per billion gold. They also identified thin veinlets of native copper in diorite rubble. The mineralization is spotty and discontinuous.
Geologic map unit (-145.096020258531, 63.2000956422459)
Mineral deposit model Cu skarn deposit (Cox and Singer, 1986; model 18b).
Mineral deposit model number 18b
Age of mineralization Unclear whether the diorite that developed the mineralized skarn is Cretaceous or Triassic.
Alteration of deposit Skarn developed at marble-diorite contact.

Production and reserves

Workings or exploration Only limited sampling by state and federal agencies.
Indication of production None
Reserve estimates None.
Production notes None.

References

References

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