Unnamed Occurrence (ARDF - UK004; near Geyser Creek), Aleutian Islands Mining District, Aleutians West Census Area, Alaska, USAi
| Regional Level Types | |
|---|---|
| Unnamed Occurrence (ARDF - UK004; near Geyser Creek) | - not defined - |
| Aleutian Islands Mining District | Mining District |
| Aleutians West Census Area | Census Area |
| Alaska | State |
| USA | Country |
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Latitude & Longitude (WGS84):
53° 12' North , 168° 30' West
Latitude & Longitude (decimal):
Köppen climate type:
This site is on land selected by the Aleut Native Corporation.
Location: This site is located near Geyser Creek on Umnak Island, approximately 3 miles southeast of Geyser Bight. Simpson's (1986) location of this site is vague and it could correspond to locations G or L which are mapped as clusters of hot-springs (Nye and others, 1992). The location is probably accurate to within 2 miles.
Geology: Geothermal activity at this site is indicated by a 800 x 2000 foot color anomaly (Simpson, 1986). The rocks here consist of propylitized andesitic flows, tuffs, and volcaniclastics of Pleistocene age. The altered rocks exhibit local zones of intense argillization and weak silicification. The clay zones contain up to 2 percent disseminated pyrite. Nye and others (1992) report dioritic and monzonitic plutons at low elevations on the east and west walls of the lower half of Geyser Creek valley, and they speculate that the plutons may host the geothermal reservoir system. Analyses of 20 rock samples indicated values up to 150 ppm arsenic, 0.58 ppm gold, 1.25 ppm mercury, and 0.2 ppm silver (Simpson, 1985, table 11, pg. 38). In general, the only rocks which contain gold are those which exhibit pyritization and moderate silicification. There does not appear to be any lateral or vertical zonation of the metals.
Workings: Twenty samples collected by Kennecott were found to contain 8 to150 ppm arsenic, 0.005 to 0.58 ppm gold, 0.005 to 1.25 ppm mercury, and 0.2 to 0.6 ppm silver (Simpson, 1986).
Age: Quaternary.
Alteration: The volcanic rocks exhibit regional propylitic alteration and local intense argillic alteration and weak silicification. The clay zones contain up to 2 percent pyrite and thin, discontinuous quartz veins.
Commodities (Major) - Ag, Au; (Minor) - As, Hg
Development Status: None
Deposit Model: Hot-spring Au-Ag (Cox and Singer, 1986; model 25a)
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
3 valid minerals.
Gallery:
List of minerals arranged by Strunz 10th Edition classification
| Group 1 - Elements | |||
|---|---|---|---|
| ⓘ | Native Gold | 1.AA.05 | Au |
| 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 |
| Au | Gold | |
| Au | ⓘ Native Gold | Au |
Other Databases
| Link to USGS - Alaska: | UK004 |
|---|
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