Unnamed (near Chitsia Mountain)

Occurrences, Inactive

Commodities and mineralogy

Main commodities Ag; Pb
Other commodities Au; Zn
Ore minerals galena
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale KH
Quadrangle map, 1:63,360-scale A-1
Latitude 64.003
Longitude -150.245
Nearby scientific data Find additional scientific data near this location
Location and accuracy Three unnamed occurrences are situated on a rounded hill approximately 3 miles northwest of Chitsia Mountain. The approximate center of the 1/2 square mile area that contains the three occurrences are NE1/4SW1/4 section 35, T. 10 S., R. 14 W., of the Fairbanks Meridian. The nearest settlement is Bearpaw, which can be accessed by the Kantishna River and a sled road from Nenana. It is locality 1 of Cobb and Chapman (1981), who summarized relevant references under the name 'Unnamed occurrence'.

Geologic setting

Geologic description

The Chitsia Mountain area is underlain by Middle Devonian to Early Mississippian Totatlanika Schist (Wilson and others, 1998). This formation consists of slightly metamorphosed volcanic sedimentary rocks, including various phyllites, silicified greenschist, and nonresistant greenschist tuffs. It is intruded by resistant porphyro-aphanitic rhyolite (Bundtzen and others, 1976). Regionally, the area contains a system of northeast-trending strike-slip and related conjugate faults associated with Cretaceous to Tertiary plutonic rocks and coeval or younger volcanic rocks (Clautice and others, 1993).
The three occurrences consist of a quartz vein system trending N 55 E and dipping 55 degrees SE, hosted in the rhyolite. The quartz veins locally contain limonite and galena. A sulfide-bearing quartz vein sample was assayed by atomic absorption and contained 0.05 ounces Ag per ton, 0.01 ounces Au per ton, less than 0.01 percent Cu, 0.01 percent Pb, 0.02 percent Zn, less than 0.01 percent Mo, and less than 0.01 percent Sb. A stream-sediment sample collected near the rhyolite was assayed by atomic absorption and contained 0.03 ppm Au, 34 ppm Cu, 24 ppm Pb, 125 ppm Zn, and 1.10 ppm Ag (Bundtzen and others, 1976). These areas of base-metal vein mineralization in rhyolite are interpreted to have potential for large low-grade and smaller high-grade metallic deposits (Bundtzen and others, 1976). There are no indications of production.
Geologic map unit (-150.247336610169, 64.0025121692036)
Mineral deposit model Plutonic-related mesothermal, shear-hosted veining.
Age of mineralization Younger than the Middle Devonian to Early Mississippian Totatlanika Schist; probably related to Cretaceous to Tertiary plutonism.

Production and reserves

Indication of production None
Production notes There are no indications of production.

References

MRDS Number A013471
Reporters Cameron S. Rombach (ADGGS)
Last report date 11/8/1999