Unnamed (near LeBlondeau Glacier)

Occurrence, Probably inactive

Commodities and mineralogy

Main commodities Ag; Cu; Zn
Other commodities Au
Ore minerals chalcopyrite; magnetite; pyrite; pyrrhotite
Gangue minerals epidote; quartz

Geographic location

Quadrangle map, 1:250,000-scale SK
Quadrangle map, 1:63,360-scale A-4
Latitude 59.23
Longitude -136.24
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is at an elevation of about 4,500 feet about 0.5 miles west of the LeBlondeau Glacier and about 0.8 mile northeast of the boundary of Glacier Bay National Park and Preserve. It is in the approximate center of a group of six locations sampled by Gilbert (1988) in the south-central part of section 25, T. 30 S., R. 54 E. of the Copper River Meridian.

Geologic setting

Geologic description

Gilbert (1988) and Still and others (1991 [BOM, v. 2, Sec. A]) describe this occurrence as, 'a magnetite-chalcopyrite skarn that crops out near a diorite-marble contact.' They note that the skarn contains magnetite lenses up to 10 feet across, with associated grossularite garnet, epidote, and marble. Nearly all of 17 rock samples collected in this area contained substantially elevated levels of copper, silver, and zinc. Values were as high as 8,540 ppm copper, 10.8 ppm silver, 11,500 ppm zinc, 620 ppm cobalt, and 0.17 ppm gold. Brief descriptions of the rock samples refer to chalcopyrite, pyrite, pyrrhotite, and magnetite in association with iron-stained diorite and skarn. The mineralization is probably the same age as the Cretaceous diorite (Gilbert, 1988).
Geologic map unit (-136.241879075209, 59.2296343347584)
Mineral deposit model Copper skarn (Cox and Singer, 1986; model 18b).
Mineral deposit model number 18b
Age of mineralization Probably Cretaceous based on the age of the associated diorite (Gilbert, 1988).
Alteration of deposit Skarn.

Production and reserves

Indication of production None

References