Unnamed (south of upper Windy Creek)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Cu
Other commodities Ag
Ore minerals chalcopyrite; malachite; pyrrhotite
Gangue minerals calcite; diopside; wollastonite

Geographic location

Quadrangle map, 1:250,000-scale HE
Quadrangle map, 1:63,360-scale B-5
Latitude 63.46
Longitude -149.14
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is at an elevation of about 4,200 feet south of upper Windy Creek, a tributary of the Nenana River. The site is at the junction of sections 5, 6, 7 and 8, T. 17 S., R. 8 W., of the Fairbanks Meridian. The location is accurate to within 3,000 feet. This is location 1 of Hickman and Craddock (1976).

Geologic setting

Geologic description

The country rocks in the area of this occurrence are Devonian to Ordovician argillite and interbedded limestone that have been intruded by small plugs of Upper Cretaceous to Lower Tertiary quartz diorite. The deposit consists of a 3- to 9-foot-wide skarn containing discontinuous, 1- to 3-foot-thick zones of pyrrhotite and minor chalcopyrite along fractures. Weathering and oxidation have produced a heavy limonitic coating, malachite, and erythrite. Samples contain 1,900 ppm copper and 0.6 ppm silver (Hickman and Craddock, 1976).
Geologic map unit (-149.142290912514, 63.4595372401055)
Mineral deposit model Cu skarn (Cox and Singer, 1986; model 18b)
Mineral deposit model number 18b
Age of mineralization Late Cretaceous or younger.
Alteration of deposit Skarn and subsequent weathering and oxidation.

Production and reserves

Workings or exploration Surface sampling only. Samples contain 1,900 ppm copper and 0.6 ppm silver (Hickman and Craddock, 1976).
Indication of production None

Additional comments

The site is in Denali National Park Wilderness.

References