Unnamed (west of Landmark Gap Lake)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Ag; Cu
Ore minerals azurite; bornite; chalcopyrite; malachite; pyrite
Gangue minerals calcite; epidote; quartz

Geographic location

Quadrangle map, 1:250,000-scale MH
Quadrangle map, 1:63,360-scale A-5
Latitude 63.1449
Longitude -146.1031
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is at an elevation of about 4,000 feet on the west side of the north end of Landmark Gap Lake (Stout, 1976, plate 1). It is in the NW1/4NW1/4 section 31, T. 20 S., R. 9 E., Fairbanks Meridian.

Geologic setting

Geologic description

This occurrence is in Nikolai Greenstone of Late Triassic age (Nokleberg and others, 1991). The unit was mapped as Boulder Creek volcanics by Stout (1976). The deposit consists of quartz-calcite-epidote veins that contain disseminated pyrite, chalcopyrite, and bornite and the oxidized copper minerals azurite and malachite. The veins occupy steep north- to northeast-trending joints that cut the limbs of the Amphitheater syncline (Stout, 1976). The veins range from less than an inch to about a foot thick.
Geologic map unit (-146.105347165411, 63.1444740609899)
Mineral deposit model Basaltic Cu (Cox and Singer, 1986; model 23).
Mineral deposit model number 23
Age of mineralization The quartz veins are localized in north-northeast-trending faults and joints that cut across the folded limbs of the Amphitheater syncline. They postdate the folding, which is of Jurassic age, and are probably either Cretaceous, related to regional metamorphism and granitic plutonism (Nokleberg and others, 1986; Kurtak and others, 1992), or early Tertiary (Stout, 1976).
Alteration of deposit Oxidation of the copper minerals.

Production and reserves

Indication of production None