Unnamed (upper Chilligan River)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Ag; Cu; Pb; Sn; Zn
Ore minerals galena; pyrite; sphalerite
Gangue minerals quartz; sericite

Geographic location

Quadrangle map, 1:250,000-scale LH
Quadrangle map, 1:63,360-scale B-1
Latitude 61.4451
Longitude -153.2218
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is on the north side of the upper Chilligan River within a small glacier-filled valley. It is at the toe of a south-flowing glacier, at an elevation of about 4,600 feet, and 1.5 miles north of Chilligan River. The map site is in the SE1/4 section 28, T 16 N, R 22 W, of the Seward Meridian. This is locality 15 of Cobb (1972 [MF 412]; 1976 [OF 76-485]) and location 30 of Gamble and others (1989). The location is probably accurate to within one-half mile.

Geologic setting

Geologic description

Reed and Elliott (1970) reported that float in a medial moraine at this locality consists of silicified and sericitized quartz monzonite that contains 5 to 10 percent galena, sphalerite, and pyrite. The sulfide minerals are in clots as much as 2 cm in diameter and in thin veinlets up to 5 mm wide. Shear zones in nearby metasedimentary rocks contain galena and sphalerite. Sulfide-bearing samples contain up to greater than 20,000 ppm lead, greater than 10,000 ppm zinc, greater than 1,000 ppm tin, 2,000 ppm copper, and 150 ppm silver. The mineralization is near the contact between a Tertiary granitic pluton and Mesozoic metamorphic rocks.
Geologic map unit (-153.224013667409, 61.4444715627727)
Mineral deposit model Polymetallic veins (Cox and Singer, 1986, model 22c)
Mineral deposit model number 22c
Age of mineralization Tertiary. Mineralization occurs in Tertiary intrusive rocks and in shear zones in nearby metasedimentary rocks.
Alteration of deposit Silicification? and sericite-pyrite replacement?

Production and reserves

Workings or exploration Reconnaissance sampling has been completed in this area (Reed and Elliott, 1970).
Indication of production None

Additional comments

This occurrence is within Lake Clark National Park.

References