Unnamed (on David Island)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Fe
Other commodities As; Bi; Cu; Mo; Pb; Sb
Ore minerals pyrite

Geographic location

Quadrangle map, 1:250,000-scale UG
Quadrangle map, 1:63,360-scale A-2
Latitude 57.034
Longitude -156.487
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is located on David Island just offshore from Port Wrangell. Site location is accurate to within 1/2 mile.

Geologic setting

Geologic description

This site is underlain by Miocene and Pliocene andesite and basalt flows, lithic tuffs, and breccias (Detterman and others, 1987). The rocks are locally silicified and exhibit other, undetermined alteration. Anomalous values in copper, molybdenum, and lead have been reported in samples of igneous rock (Wilson and O'Leary, 1986). A massive pyritic lode, 10 to 20 feet thick, is exposed at the wave base on the south side of a small point at the east end of the island and along the northeast shore (Church and others, 1989: B-1858). Grab samples of this material are anomalous in arsenic, bismuth, and antimony. Hydrothermal alteration is reportedly widespread along the northeast shore.
Geologic map unit (-156.489050235536, 57.0332735693842)
Mineral deposit model Polymetallic vein? (Cox and Singer, 1986; model 22c)
Mineral deposit model number 22c?
Alteration of deposit Silicification and other, undetermined, alteration.

Production and reserves

Workings or exploration The U.S. Geological Survey has geochemically sampled this occurrence (Church and others, 1989, B-1858).
Indication of production None

Additional comments

This site is on land selected by the Koniag Native Corporation.

References