Unnamed Occurrence (ARDF - MG048; northwest of Smith Lake), Yukon-Koyukuk Census Area, Alaska, USAi
| Regional Level Types | |
|---|---|
| Unnamed Occurrence (ARDF - MG048; northwest of Smith Lake) | - not defined - |
| Yukon-Koyukuk Census Area | Census Area |
| Alaska | State |
| USA | Country |
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Latitude & Longitude (WGS84):
62° 21' 39'' North , 153° 52' 44'' West
Latitude & Longitude (decimal):
Köppen climate type:
See also Roberts PGM (MG030), Unnamed (MG045), and Chip-Loy (MG032) prospects and deposits.
Location: The unnamed occurrence is located at the divide between the West Fork and Main Fork of Sheep creek, 8 kilometers northwest of Smith Lake, at an elevation of 5,100 feet (1,555 m) in the NE1/4 sec. 10, T. 26 N., R. 25 W., of the Seward Meridian. The reporter investigated the site in 1981.
Geology: This unnamed occurrence consists of disseminated chalcopyrite and pyrrhotite in a medium grained, phaneritic, gabbro sill thought to be a feeding system for Triassic volcanism in the Tatina River Volcanics, a unit of the Mystic subterrane (Bundtzen, Kline, and Clough, 1982). An alternative hypothesis offered by Foley (1987) is that the mafic igneous rocks that host the occurrence are flows or feeders of the Paleocene to Eocene Sheep Creek Volcanic Field as defined by Bundtzen, Harris, and Gilbert (1997). Bundtzen, Harris, and Gilbert (1997) believe that unnamed and related occurrences constitute magmatic-disseminated sulfide Cu-Ni-Co-Fe mineralization similar to deposit model 5b of Cox and Singer (1986). Selected samples of the gabbro sills in the prospect area contain up to 540 ppm copper, 190 ppm nickel, 63 ppm cobalt, and 450 ppm zinc (Foley, 1987).
Workings: The gabbro feeders were mapped by the reporter in 1981 (Bundtzen, Kline, and Clough, 1982). Selected samples of the gabbro sills in the prospect area contain up to 540 ppm copper, 190 ppm nickel, and 450 ppm zinc (Foley, 1987).
Age: Undated; inferred to be either Late Triassic or early Tertiary, based on isotopic age dates of Tatina River Volcanics and Sheep Creek Volcanic Field respectively (Bundtzen, Harris, and Gilbert, 1997).
Alteration: None.
Reserves: None.
Commodities (Major) - Cu; (Minor) - Co, Pb, Zn
Development Status: No
Deposit Model: Magmatic sulfide Cu-Ni-Co or polymetallic replacement (Cox and Singer, 1986; mo
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:
| ⓘ 'Amphibole Supergroup' Formula: AB2C5((Si,Al,Ti)8O22)(OH,F,Cl,O)2 |
| ⓘ Chalcopyrite Formula: CuFeS2 |
| ⓘ 'Clinopyroxene Subgroup' |
| ⓘ 'Fayalite-Forsterite Series' |
| ⓘ Pyrrhotite Formula: Fe1-xS |
Gallery:
List of minerals arranged by Strunz 10th Edition classification
| Group 2 - Sulphides and Sulfosalts | |||
|---|---|---|---|
| ⓘ | Chalcopyrite | 2.CB.10a | CuFeS2 |
| ⓘ | Pyrrhotite | 2.CC.10 | Fe1-xS |
| Unclassified | |||
| ⓘ | 'Amphibole Supergroup' | - | AB2C5((Si,Al,Ti)8O22)(OH,F,Cl,O)2 |
| ⓘ | 'Clinopyroxene Subgroup' | - | |
| ⓘ | 'Fayalite-Forsterite Series' | - | |
List of minerals for each chemical element
| H | Hydrogen | |
|---|---|---|
| H | ⓘ Amphibole Supergroup | AB2C5((Si,Al,Ti)8O22)(OH,F,Cl,O)2 |
| O | Oxygen | |
| O | ⓘ Amphibole Supergroup | AB2C5((Si,Al,Ti)8O22)(OH,F,Cl,O)2 |
| O | ⓘ Fayalite-Forsterite Series | |
| F | Fluorine | |
| F | ⓘ Amphibole Supergroup | AB2C5((Si,Al,Ti)8O22)(OH,F,Cl,O)2 |
| Mg | Magnesium | |
| Mg | ⓘ Fayalite-Forsterite Series | |
| Al | Aluminium | |
| Al | ⓘ Amphibole Supergroup | AB2C5((Si,Al,Ti)8O22)(OH,F,Cl,O)2 |
| Si | Silicon | |
| Si | ⓘ Amphibole Supergroup | AB2C5((Si,Al,Ti)8O22)(OH,F,Cl,O)2 |
| Si | ⓘ Fayalite-Forsterite Series | |
| S | Sulfur | |
| S | ⓘ Chalcopyrite | CuFeS2 |
| S | ⓘ Pyrrhotite | Fe1-xS |
| Cl | Chlorine | |
| Cl | ⓘ Amphibole Supergroup | AB2C5((Si,Al,Ti)8O22)(OH,F,Cl,O)2 |
| Ti | Titanium | |
| Ti | ⓘ Amphibole Supergroup | AB2C5((Si,Al,Ti)8O22)(OH,F,Cl,O)2 |
| Fe | Iron | |
| Fe | ⓘ Chalcopyrite | CuFeS2 |
| Fe | ⓘ Pyrrhotite | Fe1-xS |
| Fe | ⓘ Fayalite-Forsterite Series | |
| Cu | Copper | |
| Cu | ⓘ Chalcopyrite | CuFeS2 |
Other Databases
| Link to USGS - Alaska: | MG048 |
|---|
Other Regions, Features and Areas containing this locality
North AmericaContinent
North America PlateTectonic Plate
- Farewell-McGrath DomainDomain
- Farewell TerranePassive Margin
USA
- Alaska
- Yukon-Koyukuk Census Area
- McGrath Mining DistrictMining District
- Yukon-Koyukuk Census Area
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