Unnamed (near Bush Mountain)

Occurrence, Undetermined

Commodities and mineralogy

Main commodities Ag; Au; Cu
Ore minerals pyrite; pyrrhotite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale KC
Quadrangle map, 1:63,360-scale A-5
Latitude 55.223
Longitude -131.518
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is at an elevation of about 1600 feet on the south slope of Bush Mountain, about 0.45 mile south-southwest of the top of the mountain. The site is in section 2, T. 77 S., R. 92 E., of the Copper River Meridian. It corresponds to loc. 8 in Karl (1992). The location is accurate within about 300 feet.

Geologic setting

Geologic description

The country rocks in the area of this site are Upper Jurassic or Cretaceous flyschlike metasedimentary rocks that are gradationally interbedded with andesitic or basaltic metatuff (Berg, 1972 [I 684]; Berg and others, 1988; Karl, 1992). The rocks were regionally metamorphosed to greenschist-grade phyllite and semischist in Late Cretaceous time.
The occurrence consist of green tuffaceous phyllite and gray argillaceous phyllite that contain disseminated pyrite, and of quartz-pyrite veins (Karl, 1992, loc. 6). The pyrite also coats fractures in the country rocks. Locally, the pyrite is accompanied by pyrrhotite. Samples of green phyllite containing disseminations and veins of sulfide minerals assayed up to 0.1 ppm Au, 3 ppm Ag, and 1000 ppm Cu.
Geologic map unit (-131.519681911744, 55.222654793115)
Mineral deposit model Low-sulfide Au-quartz veins (Cox and Singer, 1986; model 36a)
Mineral deposit model number 36a
Age of mineralization Probably Late Cretaceous or younger.
Alteration of deposit Pyritization of tuffaceous phyllite country rock.

Production and reserves

Workings or exploration Samples of green phyllite containing disseminations and veins of sulfide minerals assayed up to 0.1 ppm Au, 3 ppm Ag, and 1000 ppm Cu.
Indication of production None

References