Unnamed Occurrence (ARDF - MG085; near tributary to South Fork of Kuskokwim River), McGrath Mining District, Bethel Census Area, Alaska, USAi
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Latitude & Longitude (WGS84):
62° 2' 38'' North , 153° 24' 39'' West
Latitude & Longitude (decimal):
Köppen climate type:
Location: This occurrence is located on a north-facing spur overlooking an unnamed tributary of the South Fork of the Kuskokwim River. It is at an elevation of 5,100 feet (1,555 m) in the NW1/4 sec. 36, T. 23 N., R. 23 W., of the Seward Meridian. The location is based on field mapping by D.N. Solie, formerly of the Alaska Division of Geological and Geophysical Surveys; at station no. 88DNS107. The occurrence corresponds to map number 35 in Bundtzen, Harris, and Gilbert (1997).
Geology: This unnamed occurrence is a stockwork of pyrite-galena-quartz that cuts a small granodiorite porphyry intrusion and altered dacitic tuffs. The mineralized zone occurs near the contact between igneous rocks of the Terra Cotta Volcanic Field and Lower Cretaceous Kahiltna flysch (Bundtzen, Harris, and Gilbert, 1997). No precise structural or size measurements of the mineralized zone are available. Grab samples from talus contain up to 4,000 ppm arsenic, 2,100 ppb gold, 66 ppm cobalt, 110 ppm antimony, and 550 ppm tungsten (Bundtzen, Harris, and Gilbert, 1997).
Workings: D.N. Solie discovered the mineralized area during geologic mapping for the Alaska Division of Geological and Geophysical Surveys in 1988. Grab samples from the talus contain up to 4,000 ppm arsenic, 2,100 ppb gold, 66 ppm cobalt, 110 ppm antimony, and 550 ppm tungsten (Bundtzen, Harris, and Gilbert, 1997).
Alteration: Sericite.
Reserves: None.
Commodities (Major) - As, Au, W; (Minor) - Co, Sb
Development Status: No
Deposit Model: Creede epithermal vein (?) (Cox and Singer, 1986; model 25b).
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
4 valid minerals.
Detailed Mineral List:
| ⓘ Arsenopyrite Formula: FeAsS |
| ⓘ Galena Formula: PbS |
| ⓘ Pyrite Formula: FeS2 |
| ⓘ Quartz Formula: SiO2 |
Gallery:
List of minerals arranged by Strunz 10th Edition classification
| Group 2 - Sulphides and Sulfosalts | |||
|---|---|---|---|
| ⓘ | Galena | 2.CD.10 | PbS |
| ⓘ | Pyrite | 2.EB.05a | FeS2 |
| ⓘ | Arsenopyrite | 2.EB.20 | FeAsS |
| 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 | ⓘ Arsenopyrite | FeAsS |
| S | ⓘ Galena | PbS |
| S | ⓘ Pyrite | FeS2 |
| Fe | Iron | |
| Fe | ⓘ Arsenopyrite | FeAsS |
| Fe | ⓘ Pyrite | FeS2 |
| As | Arsenic | |
| As | ⓘ Arsenopyrite | FeAsS |
| Pb | Lead | |
| Pb | ⓘ Galena | PbS |
Other Databases
| Link to USGS - Alaska: | MG085 |
|---|
Other Regions, Features and Areas containing this locality
North AmericaContinent
North America PlateTectonic Plate
- Farewell buried DomainDomain
- Farewell TerranePassive Margin
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