Unnamed (south-southeast of Turn Mountain)

Occurrence, Undetermined

Commodities and mineralogy

Main commodities Ag; Cu; Mo
Ore minerals chalcopyrite; pyrite
Gangue minerals epidote; potassium feldspar; quartz

Geographic location

Quadrangle map, 1:250,000-scale SD
Quadrangle map, 1:63,360-scale A-6
Latitude 57.05296
Longitude -133.82883
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is about 1.0 mile south-southeast of Turn Mountain in a borrow pit along a logging road. It is about 0.5 mile southwest of the center of section 33, T. 55 S., R. 73 E.

Geologic setting

Geologic description

This occurrences was first identified by Still and others (2002). It consists of a shear zone that cuts an intrusive body of Cretaceous black hornblendite that varies to dark gray hornblende gabbro (Karl and others, 1999). The shear zone contains quartz, potassium feldspar, and epidote, with pyrite and chalcopyrite. A layer of weathered pyrite about 1 to 3 inches thick with lenses of chalcopyrite is exposed along the shear zone for about 15 feet in the wall of a borrow pit. A select sample contained 30.6 parts per million (ppm) silver, 11.2 percent copper, and 1,253 ppm molybdenum (Still and others, 2002).
Geologic map unit (-133.830560324593, 57.0526227161079)
Mineral deposit model Shear zone with copper and molybdenum values.
Age of mineralization The deposit is along a shear zone in Cretaceous hornblendite to gabbro.

Production and reserves

Workings or exploration Only surface sampling by government geologists.
Indication of production None

References

References

Still, J.C., Bittenbender, P.E., Bean, K.W., and Gensler, E.G., 2002 Mineral assessment of the Stikine area, central Southeast Alaska: U.S. Bureau of Land Management Technical Report 51, 560 p.
Reporters Donald Grybeck (U.S. Geological Survey)
Last report date 10/8/2004