Unnamed Occurrence (ARDF - MG087; on tributary to South Fork of Kuskokwim River), McGrath Mining District, Bethel Census Area, Alaska, USAi
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Latitude & Longitude (WGS84):
62° 0' 50'' North , 153° 24' 32'' West
Latitude & Longitude (decimal):
Köppen climate type:
Location: This unnamed occurrence is located in the steep canyon of a northeast-flowing tributary to the South Fork of the Kuskokwim River; it is at an elevation of 3,950 feet (1,204 m) in the NW1/4 sec. 12, T. 22 N., R. 23 W., of the Seward Meridian. The reporter investigated the site in 1988; at station no. 88BT165.
Geology: This unnamed occurrence is a series of sheeted quartz-pyrite veins in Lower Cretaceous Kahiltna flysch adjacent to several, east-west-trending rhyolite dikes cutting the flysch (Bundtzen, Harris, and Gilbert, 1997). The quartz veins dip south and are parallel to the east-west-trending dikes. The Kahiltna flysch is locally thermally upgraded to slate. One sample contained 830 ppm arsenic, 180 ppb gold, and 710 ppm tungsten. A panned concentrate taken just below the mineralized dike swarm contained 1.00 percent tin and 1,400 ppm tungsten.
Workings: The reporter visited and sampled the site in 1988; anomalous pan concentrate samples were collected by Ellen E. Harris. One sample of sheeted veining contained 830 ppm arsenic, 180 ppb gold, and 710 ppm tungsten. A panned concentrate taken just below the mineralized dike swarm contained 1.00 percent tin and 1,400 ppm tungsten (Bundtzen, Harris, and Gilbert, 1997).
Reserves: None.
Commodities (Major) - As, Au; (Minor) - W
Development Status: No
Deposit Model: Polymetallic vein (Cox and Singer, 1986; model 22c).
Select Mineral List Type
Standard Detailed Gallery Strunz Chemical ElementsCommodity List
This is a list of exploitable or exploited mineral commodities recorded at this locality.Mineral List
2 valid minerals.
Gallery:
List of minerals arranged by Strunz 10th Edition classification
| Group 2 - Sulphides and Sulfosalts | |||
|---|---|---|---|
| ⓘ | Pyrite | 2.EB.05a | FeS2 |
| Group 4 - Oxides and Hydroxides | |||
| ⓘ | Quartz | 4.DA.05 | SiO2 |
List of minerals for each chemical element
| O | Oxygen | |
|---|---|---|
| O | ⓘ Quartz | SiO2 |
| Si | Silicon | |
| Si | ⓘ Quartz | SiO2 |
| S | Sulfur | |
| S | ⓘ Pyrite | FeS2 |
| Fe | Iron | |
| Fe | ⓘ Pyrite | FeS2 |
Other Databases
| Link to USGS - Alaska: | MG087 |
|---|
Other Regions, Features and Areas containing this locality
North AmericaContinent
North America PlateTectonic Plate
- Farewell buried DomainDomain
- Farewell TerranePassive Margin
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