| Main commodities | Au |
|---|---|
| Ore minerals | arsenopyrite; gold |
| Gangue minerals | quartz |
| Quadrangle map, 1:250,000-scale | AN |
|---|---|
| Quadrangle map, 1:63,360-scale | D-6 |
| Latitude | 61.8 |
| Longitude | -149.25 |
| Nearby scientific data | Find additional scientific data near this location |
| Location and accuracy | Near headwaters of Sydney Creek, a tributary of Archangel Creek. Accurate within 2,500 ft. Locality 20 of Cobb (1972) and locality 17 of MacKevett and Holloway (1977). |
Geologic descriptionA white banded quartz vein cuts a gouge zone in quartz diorite country rock of the Late Cretaceous Willow Creek Pluton. The vein strikes N 35 W, dips 45 SW, and contains arsenopyrite and gold. The vein swells and pinches with a maximum thickness of 30 inches (Capps, 1919). The Willow Creek Pluton is a zoned pluton: the outer part consists of hornblende quartz diorite and lesser hornblende tonalite; the core consists of hornblende-biotite granodiorite, and lesser hornblende-biotite quartz monzodiorite and biotite quartz monzonite. Wall-rock alteration within a few inches of the veins is intense, but seldom extends more than 10 to 12 inches beyond the quartz filling. Sericitization and carbonate alteration predominate, but there is some pyritization and in the outer parts of the alteration zone chloritization is present (Ray, 1954). | |
| Geologic map unit | (-149.25221067431, 61.7994710032036) |
|---|---|
| Mineral deposit model | Low-sulfide Au-quartz veins (Cox and Singer, 1986; model 36a) |
| Mineral deposit model number | 36a |
| Age of mineralization | Late Cretaceous or younger; vein cuts the Late Cretaceous Willow Creek Pluton. |
| Alteration of deposit | Wall-rock alteration within a few inches of the veins is intense, but seldom extends more than 10 to 12 inches beyond the quartz filling. Sericitization and carbonate alteration predominate, but there is some pyritization and in the outer parts of the alteration zone chloritization is present (Ray, 1954). |
| Workings or exploration | Explored by 160 ft tunnel and another 30 ft tunnel that never penetrated loose surficial material (Capps, 1919). |
|---|---|
| Indication of production | Undetermined |
| MRDS Number | A011622 |
|---|---|
| Reporters | D.P. Bickerstaff (USGS contractor); S.W. Huss (USGS) |
| Last report date | 7/30/1998 |