Twin Lakes East

Occurrence, Inactive

Commodities and mineralogy

Main commodities Cu
Ore minerals bornite; chalcopyrite; pyrrhotite

Geographic location

Quadrangle map, 1:250,000-scale LC
Quadrangle map, 1:63,360-scale C-2
Latitude 60.72
Longitude -153.7
Nearby scientific data Find additional scientific data near this location
Location and accuracy Locality is on Peak 6,515 approximately 4.8 km NE of the eastern end of Twin Lakes. This is locality 12 of Nelson and others (1985) and locality 20 of MacKevett and Holloway (1977). Sec. 8, T. 7 N., R. 25 W., of the Seward Meridian. Locality is accurate to within 1.6 km.

Geologic setting

Geologic description

Disseminated chalcopyrite, bornite, and associated pyrrhotite occur in mafic to intermediate metavolcanic rocks interbedded with marble (Nelson and others, 1985; 1983, unit Tvf). Nelson and others (1983) report small intrusive bodies that range in composition from granite to gabbro also occur in vicinity. Potassium-argon ages range from 56.2 to 62.7 m.y. (Eakins and others, 1978).
Geologic map unit (-153.702262544059, 60.7193405372519)
Mineral deposit model Kuroko massive sulfide? or Porphyry Cu, skarn related? (Cox and Singer, 1986; model 28a? or 18a?)
Mineral deposit model number 28a? or 18a?
Age of mineralization The metavolcanic rocks that host the mineralization have potassium-argon ages, by D.L. Turner, that range from 56.2 to 62.7 m.y. (Eakins and others, 1983).
Alteration of deposit Unknown

Production and reserves

Workings or exploration Unknown
Indication of production None
Reserve estimates No reserves
Production notes No production

Additional comments

Site is in Lake Clark National Park and Preserve.


MRDS Number A106367


Resource Associates of Alaska, Inc., 1976, Geology and geochemistry of certain land within the Lake Clark National Park: Contract report for U.S. Bureau of Mines, Contract JO166108, 7 v.
Reporters D.P. Bickerstaff (USGS)
Last report date 6/15/1998