Unnamed Occurrence (ARDF - SP026; near headwaters of Takahula River), Koyukuk Mining District, Yukon-Koyukuk Census Area, Alaska, USAi
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Latitude & Longitude (WGS84):
67° 19' 12'' North , 153° 59' 24'' West
Latitude & Longitude (decimal):
Köppen climate type:
Located within Gates of the Arctic National Park.
Location: This site is at an elevation of about 3500 feet near the headwaters of the Takahula River. It is in the N1/2 of sec. 9, T. 22 N., R. 22 E., of the Kateel River Meridian. The location is accurate to within 2000ft. The site corresponds to locality 52 of Grybeck and Nelson (1981).
Geology: This occurrence consists of a skarn deposit in an approximately 1000 x 500 ft. area at the contact of Devonian granite with Paleozoic calcareous rocks (Nelson and Grybeck, 1980). Epidote-garnet, magnetite-quartz-hornblende, and magnetite-hornblende skarns contain erratically distributed sphalerite and fluorite. Analyses of numerous grab samples show as much as 7000 ppm As, and most show 700 to 1000 ppm Be, 100 to 200 ppm Bi, and 500 to 1000 ppm Zn. Sn values range from 500 to more than 1000 ppm Sn, but petrographic examination indicates that the Sn is not present as an oxide or sulfide. This occurrence is one of many skarn deposits adjacent to the Devonian granite and is similar to others elsewhere in the Brooks Range (Newberry and others, 1986).
Age: Devonian; related to the intrusion of Devonian pluton.
Alteration: Contact metamorphic.
Commodities (Major) - F, Sn, Zn; (Minor) - As, Be, Bi, Sn
Development Status: None
Deposit Model: Skarn (Cox and Singer, 1986; model 14b)
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.
Detailed Mineral List:
| ⓘ Fluorite Formula: CaF2 |
| ⓘ Sphalerite Formula: ZnS |
Gallery:
List of minerals arranged by Strunz 10th Edition classification
| Group 2 - Sulphides and Sulfosalts | |||
|---|---|---|---|
| ⓘ | Sphalerite | 2.CB.05a | ZnS |
| Group 3 - Halides | |||
| ⓘ | Fluorite | 3.AB.25 | CaF2 |
List of minerals for each chemical element
| F | Fluorine | |
|---|---|---|
| F | ⓘ Fluorite | CaF2 |
| S | Sulfur | |
| S | ⓘ Sphalerite | ZnS |
| Ca | Calcium | |
| Ca | ⓘ Fluorite | CaF2 |
| Zn | Zinc | |
| Zn | ⓘ Sphalerite | ZnS |
Other Databases
| Link to USGS - Alaska: | SP026 |
|---|
Other Regions, Features and Areas containing this locality
North AmericaContinent
- Brooks RangeMountain Range
- Rocky MountainsMountain Range
North America PlateTectonic Plate
- Brooks Range DomainVolcanic Arc
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