Unnamed (south of Chitina River)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Ag; Au; Cu; Mo
Ore minerals chalcopyrite

Geographic location

Quadrangle map, 1:250,000-scale MC
Quadrangle map, 1:63,360-scale A-4
Latitude 61.0211
Longitude -142.2271
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is in the headwaters of Coffee Creek, a south tributary to the Chitina River. It is on the west side of a cirque valley at an elevation of about 5,200 feet, 6,000 feet southwest of elevation 5816. The occurrence is about 2,100 feet north of the center of section 9, T. 10 S., R. 18 E. of the Copper River Meridian. This is locality 5 of MacKevett (1976); the location is accurate to within about 1,000 feet.

Geologic setting

Geologic description

This occurrence consists of sulfide minerals in quartz veins to 15 centimeters wide and disseminated sulfides in Jurassic quartz diorite of the Chitina Valley batholith (MacKevett, 1976, 1978). A sample of selected quartz vein material contained 30 parts per million (ppm) silver, 2 ppm gold, 20,000 ppm copper, and 70 ppm molybdenum. K/Ar dates for the host Chitina Valley batholith range from 138 to 146 +/- 4 Ma (MacKevett, 1978).
Geologic map unit (-142.229104800878, 61.0206678157986)
Mineral deposit model Polymetallic veins (Cox and Singer, 1986; model 22c)
Mineral deposit model number 22c
Age of mineralization Late Jurassic(?) based on K/Ar dates for the host Chitina Valley batholith which range from 138 to 146 +/- 4 Ma (MacKevett, 1978).
Alteration of deposit Silicification.

Production and reserves

Workings or exploration Limited surface sampling.
Indication of production None

Additional comments

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

References