Unnamed (on tributary valley to Happy River)

Occurrence, Inactive

Commodities and mineralogy

Main commodities As; W
Other commodities Au
Ore minerals chalcopyrite; pyrite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale MG
Quadrangle map, 1:63,360-scale A-1
Latitude 62.187
Longitude -153.019
Nearby scientific data Find additional scientific data near this location
Location and accuracy This unnamed occurrence is located on a steep, west-facing slope of a tributary valley to the Happy River. It is at about 4 kilometers southeast of Rainy Pass, at an elevation of 4,400 feet (1,341 m), in the NE1/4 sec. 7, T. 24 N., R. 20 W., of the Seward Meridian. The reporter visited the site in 1988; at station no. 88BT205.

Geologic setting

Geologic description

This unnamed occurrence consists of a chalcopyrite-bearing quartz vein in the contact aureole of a small composite hornblende-rich, granodiorite pluton that intrudes Lower Cretaceous Kahiltna Flysch (Bundtzen, Harris, and Gilbert, 1997). The undated pluton contains monzonite, granodiorite, and syenite phases with granodiorite predominates. The small intrusion covers an area of 100 meters by 200 meters; however, a 125 meter wide thermal aureole surrounds the intrusion, which suggests an enlarged body at depth.
Chalcopyrite-bearing quartz veins occur in the thermal aureole near the contact with the pluton. Chalcopyrite comprises no more than one percent of the total sulfides, which are dominated by pyrite. Three samples taken of the sulfide-vein mineralization contained an average 180 ppm tungsten, 200 ppm arsenic, and 250 ppm gold. The samples were not run for either lead or copper.
Geologic map unit (-153.021246676329, 62.1864095744962)
Mineral deposit model Polymetallic vein (Cox and Singer, 1986; model 22c).
Mineral deposit model number 22c
Alteration of deposit Sericite in intrusion.

Production and reserves

Workings or exploration The reporter mapped the pluton as part of a Division of Geological and Geophysical Surveys mapping effort in 1988 (Bundtzen, Harris, and Gilbert, 1997). Three samples taken of sulfide-vein mineralization contained an average 180 ppm tungsten, 200 ppm arsenic, and 250 ppm gold. The samples were not analyzed for lead or copper.
Indication of production None
Reserve estimates None.

References