| 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 descriptionThis 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. |
| Workings or exploration | The U.S. Geological Survey has geochemically sampled this occurrence (Church and others, 1989, B-1858). |
|---|---|
| Indication of production | None |
Additional commentsThis site is on land selected by the Koniag Native Corporation. | |
| MRDS Number | 10308460 |
|---|---|
References | |
| Reporters | S.H. Pilcher (Anchorage) |
| Last report date | 2/1/2000 |