Hidden Lake Occurrence, Valdez Creek Mining District, Matanuska-Susitna Borough, Alaska, USAi
| Regional Level Types | |
|---|---|
| Hidden Lake Occurrence | Occurrence |
| Valdez Creek Mining District | Mining District |
| Matanuska-Susitna Borough | Borough |
| Alaska | State |
| USA | Country |
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Latitude & Longitude (WGS84):
63° 14' 46'' North , 146° 32' 52'' West
Latitude & Longitude (decimal):
Type:
Köppen climate type:
Location: This occurrence is northwest of Hidden Lake at an elevation of about 3,200 feet, about on the boundary between sections 23 and 26, T. 19 S., R. 6 E., Fairbanks Meridian. The site corresponds to locality 16 of Kaufman (1964), probably to locality 13 of Saunders (1961 [report for the year]), and to locality 26 of Cobb (1979 [OFR 79-238]).
Geology: The host rock of this occurrence is basaltic greenstone, probably equivalent to the Nikolai Greenstone of Late Triassic age (Nokleberg and others, 1991). Disseminated and pod-like masses of bornite, chalcopyrite, and oxidized copper minerals occur with quartz-epidote veins. There is little apparent continuity in the distribution of copper at the site (Kaufman, 1964, p. 8).
Workings: There are no reported workings.
Age: The epigenetic copper deposits are younger than Late Triassic and formed after a pre-Late Jurassic folding event (Stout, 1976). The deposits could have formed in Cretaceous or early Tertiary time (see MH060) during weak greenschist metamorphism of the Nikolai Greenstone.
Alteration: Oxidation of iron- and copper-bearing minerals.
Commodities (Major) - Cu
Development Status: No
Deposit Model: Low-sulfide copper-bearing quartz-epidote veins. Basaltic Cu (Cox and Singer, 1
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:
| ⓘ Bornite Formula: Cu5FeS4 |
| ⓘ Chalcopyrite Formula: CuFeS2 |
| ⓘ 'Copper Stain' |
| ⓘ Epidote Formula: (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
| ⓘ Quartz Formula: SiO2 |
Gallery:
List of minerals arranged by Strunz 10th Edition classification
| Group 2 - Sulphides and Sulfosalts | |||
|---|---|---|---|
| ⓘ | Bornite | 2.BA.15 | Cu5FeS4 |
| ⓘ | Chalcopyrite | 2.CB.10a | CuFeS2 |
| Group 4 - Oxides and Hydroxides | |||
| ⓘ | Quartz | 4.DA.05 | SiO2 |
| Group 9 - Silicates | |||
| ⓘ | Epidote | 9.BG.05a | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
| Unclassified | |||
| ⓘ | 'Copper Stain' | - | |
List of minerals for each chemical element
| H | Hydrogen | |
|---|---|---|
| H | ⓘ Epidote | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
| O | Oxygen | |
| O | ⓘ Epidote | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
| O | ⓘ Quartz | SiO2 |
| Al | Aluminium | |
| Al | ⓘ Epidote | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
| Si | Silicon | |
| Si | ⓘ Epidote | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
| Si | ⓘ Quartz | SiO2 |
| S | Sulfur | |
| S | ⓘ Bornite | Cu5FeS4 |
| S | ⓘ Chalcopyrite | CuFeS2 |
| Ca | Calcium | |
| Ca | ⓘ Epidote | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
| Fe | Iron | |
| Fe | ⓘ Bornite | Cu5FeS4 |
| Fe | ⓘ Chalcopyrite | CuFeS2 |
| Fe | ⓘ Epidote | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
| Cu | Copper | |
| Cu | ⓘ Bornite | Cu5FeS4 |
| Cu | ⓘ Chalcopyrite | CuFeS2 |
Other Databases
| Link to USGS - Alaska: | MH085 |
|---|
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