Ahua

Occurrence, Inactive

Commodities and mineralogy

Main commodities Cu
Other commodities Ag; Pb
Ore minerals marcasite; pyrite

Geographic location

Quadrangle map, 1:250,000-scale BM
Quadrangle map, 1:63,360-scale C-6
Latitude 67.73
Longitude -161.73
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Ahua prospect is at an elevation of about 1,000 feet near a south-flowing creek that drains the Kilyaktalik Peaks. It is in section 24, T. 27 N., R. 14 W., of the Kateel River Meridian. Schmidt and Allegro (1988), location 47 and field stations 84RB103 and 84JS030.

Geologic setting

Geologic description

The Ahua occurrence consists of stained and bleached zones in black shale containing lenses of massive, botryoidal pyrite-marcasite. Samples of the sulfides contain as much as 60 ppm As, 2 ppm Ag, 100 ppm Zn, 5 ppm Ag, 700 ppm Ba, 20 ppm Co, 200 ppm Cu, 20 percent Fe, 30 ppm Mo, 100 ppm Ni and 50 ppm Pb. Pyrite-rich samples contain as much as 200 ppm Cu, 50 ppm Pb, 30 ppm Mo, 100 ppm Ni, 100 ppm Zn, 5 ppm Ag, 60 ppm As, 700 ppm Ba, and 20 ppm Co (Schmidt and Allegro, 1988). The host rocks are Lower Mississippian black shale that are similar to the Kuna Formation (Karl and others, 1985).
Geologic map unit (-161.73290140232, 67.7293644315364)
Mineral deposit model Sedimentary exhalative Zn-Pb (Cox and Singer, 1986; model 31a).
Mineral deposit model number 31a
Age of mineralization Early Mississippian.
Alteration of deposit Sulfide-bearing black shale is stained and bleached.

Production and reserves

Workings or exploration The occurrence has been visited and sampled by the U.S. Geological Survey (Schmidt and Allegro, 1988).
Indication of production None

References

MRDS Number 10307260
Reporters Anita Williams (Anchorage, AK)
Last report date 12/29/1999