Unnamed (southwest of Indian Pass Lake)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Au
Ore minerals gold; pyrite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale NB
Quadrangle map, 1:63,360-scale D-6
Latitude 62.8065
Longitude -143.988
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is on a ridge between two unnamed west tributaries of Porcupine Creek. It is close to a saddle at an elevation of about 4,700 feet, about 1.1 miles west of the Eagle trail, in the SW1/4 of section 19, T. 12 N., R. 8 E. of the Copper River Meridian. This is locality 1 of Richter and others (1975). It is located to within several hundred feet. Cobb and Richter (1980) included this occurrence under the name 'Indian Pass Lake'.

Geologic setting

Geologic description

Disseminated pyrite and small quartz-pyrite veins occur in a small hornblende diorite stock that intrudes late Paleozoic andesitic rocks of the Tetelna Volcanics (Richter, 1966, 1976; Richter and others, 1975). A sample of hornblende diorite with minor disseminated pyrite from this locality contained 0.3 part per million gold (sample R60, Richter and Matson, 1968). Plutonic rocks in this area are part of a Pennsylvanian magmatic suite that varies from gabbro to granite and has U-Pb zircon ages between 290 and 320 Ma (Richter, Lanphere, and Matson, 1975; Miller, 1994, p. 541-542).
Geologic map unit (-143.990193647817, 62.806112141071)
Mineral deposit model Polymetallic veins and/or porphyry Cu-Au (Cox and Singer, 1986; models 22c and 20c)
Mineral deposit model number 22c; 20c
Age of mineralization Probably Pennsylvanian, the age of plutonic rocks in the area.
Alteration of deposit Oxidation; pyrite-bearing rocks in this area are commonly limonite-stained (Richter, 1966).

Production and reserves

Indication of production None