Unnamed Occurrence (ARDF - MH181; west of Landmark Gap Lake), Delta River Mining District, Valdez-Cordova Census Area, Alaska, USAi

Regional Level Types
Unnamed Occurrence (ARDF - MH181; west of Landmark Gap Lake)	- not defined -
Delta River Mining District	Mining District
Valdez-Cordova Census Area	Census Area
Alaska	State
USA	Country

Location: 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.
Geology: 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.
Age: The quartz veins are localized in north-northeast-trending faults and joints that cut across the folded limbs of the Amphitheater syncline. They post-date 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: Oxidation of the copper minerals.

Commodities (Major) - Ag, Cu
Development Status: None
Deposit Model: Basaltic Cu (Cox and Singer, 1986; model 23).

Other Databases

Link to USGS - Alaska:	MH181

Other Regions, Features and Areas containing this locality

References