Nikolai

Prospect, Inactive

Commodities and mineralogy

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

Geographic location

Quadrangle map, 1:250,000-scale MC
Quadrangle map, 1:63,360-scale B-5
Latitude 61.4637
Longitude -142.6765
Nearby scientific data Find additional scientific data near this location
Location and accuracy This prospect is on the north fork of Nikolai Creek (MacKevett, 1974). It is at an elevation of about 4,300 feet, 2,000 feet east-southeast of elevation 4670, and 1,500 feet west of the center of section 2, T. 5 S., R. 15 E. of the Copper River Meridian. This is locality 75 of MacKevett (1976) and it is accurately located. Cobb and MacKevett (1980) include this prospect under the name 'Nikolai'. This mine is shown on the McCarthy B-5 topographic map (1994 edition).

Geologic setting

Geologic description

This prospect consists of two iron-stained quartz-calcite-epidote veins, 1 to 4 feet thick, that contain bornite, chalcopyrite, pyrite, pyrrhotite, and malachite (Miller, 1946). The veins are localized in shear zones that cut Triassic Nikolai Greenstone about 150 feet below the contact with overlying Triassic Chitistone Limestone. The veins were first staked in 1899 and 7 claims were patented in 1904. About 300 feet of underground workings, completed by 1911, explored the deposits. Perhaps 1,500 tons of material that contain 25 percent or more copper were delineated (Miller, 1946). Copper mineralization is common in Nikolai Greenstone and is thought to have accompanied regional deformation and low-grade metamorphism in the Late Jurassic to Early Cretaceous (MacKevett and others, 1997).
Geologic map unit (-142.678572507273, 61.4632657789515)
Mineral deposit model Kennecott-type copper deposit (after MacKevett and others, 1997)
Age of mineralization Cretaceous? Copper mineralization is common in Nikolai Greenstone and is thought to have accompanied regional deformation and low-grade metamorphism in the Late Jurassic to Early Cretaceous (MacKevett and others, 1997).
Alteration of deposit Oxidation.

Production and reserves

Workings or exploration The veins were first staked in 1899 and 7 claims were patented in 1904. About 300 feet of underground workings, completed by 1911, explored the deposits and perhaps 1,500 tons of material with 25 percent or more copper were delineated (Miller, 1946).
Indication of production None
Reserve estimates About 1,500 tons of material with 25 percent or more copper were delineated by underground exploration (Miller, 1946).

Additional comments

The locality is in the Wrangell-Saint Elias National Park and Preserve.

References