Blue Bird

Prospect, Inactive

Commodities and mineralogy

Main commodities Au; Cu
Ore minerals bornite; chalcocite; chalcopyrite; covellite; enargite; malachite
Gangue minerals calcite; epidote

Geographic location

Quadrangle map, 1:250,000-scale VA
Quadrangle map, 1:63,360-scale C-1
Latitude 61.6617
Longitude -144.0308
Nearby scientific data Find additional scientific data near this location
Location and accuracy This prospect is on the crest of the divide between the upper Middle Fork and East Fork Copper Creek (Val Alstine and Black, 1946, plate 30); it is at an elevation of about 5,300 feet nearly in the center of the S1/2 section 30, T. 2 S., R. 8 E., of the Copper River Meridian. This prospect is approximately located, probably to within one-quarter mile. It is included in locality 72 of Cobb and Matson (1972) and locality 58 of Winkler and others (1981 [OFR 80-892-B]).

Geologic setting

Geologic description

Triassic Nikolai Greenstone is cut by shear zones that contain calcite-epidote veinlets and small amounts of pyrite, bornite, and enargite. These sulfides are also disseminated in small grains (Van Alstine and Black, 1946). This prospect was explored by two open cuts, and about 100 pounds of hand-sorted bornite and enargite were left near each cut. A polished section of this material showed covellite inclusions in enargite. Chalcocite occurs on the borders of bornite grains, as veinlets in bornite, and as irregular patches replacing bornite (Van Alstine and Black, 1946). The copper mineralization is believed to be related to the regional mineralizing event that produced the rich Kennecott copper deposits in the McCarthy quadrangle (MacKevett and others, 1997).
Geologic map unit (-144.032894453514, 61.6612343801654)
Mineral deposit model Veins, disseminations, and fracture fillings in greenstone; probably related to Kennecott-type copper deposits (MacKevett and others, 1997)
Age of mineralization The copper mineralization is believed to be related to the mineralizing event that produced the rich Kennecott copper deposits in the McCarthy quadrangle to the east (MacKevett and others, 1997). This event is interpreted to have accompanied Late Jurassic or Early Cretaceous deformation and metamorphism (MacKevett and others, 1997, p. 88).

Production and reserves

Workings or exploration Van Alstine and Black (1946) reported that two open cuts explored this prospect.
Indication of production None

Additional comments

This prospect is within the Wrangell-St. Elias National Park.

References