Amethyst prospect, Alaska Peninsula District, Aleutians East Borough, Alaska, USA
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| Latitude & Longitude (WGS84): | 55° 11' 16'' North , 160° 39' 14'' West |
|---|---|
| Latitude & Longitude (decimal): | 55.18778,-160.65389 |
| KΓΆppen climate type: | Dfc : Subarctic climate |
This prospect is located on land patented by, or interim-conveyed to, the Aleut Corporation.
Location: The map site of the Amethyst prospect is at an elevation of 500 feet, 500 feet northwest of the center of sec 3, T. 58 S., R. 75 W., Seward Meridian. The location is accurate to within 1,200 feet.
Geology: The northeast-striking Amethyst vein at its westernmost end is located approximately 200 feet south of the Altair vein (PM091); however, it has a more northerly strike, and farther to the northeast it intersects both the Altair (PM091) and the Ankle Creek (PM090) veins (Peterson and others, 1982, figure 11). The Amethyst vein has been traced for approximately 2,000 feet on strike. The vein is a braided system, generally 15 to 20 feet in width, composed of numerous quartz veins of varying widths. Individual veins in the system branch, interweave, pinch, and swell (Trujillo and others, 1982). It exhibits evidence of crushing, brecciation, and partial rehealing. Vein quartz generally makes up 20 to 50 percent of the system. Sulfide minerlas include pyrite, chalcopyrite, galena, and sphalerite. The host rocks are propylitized and argillized, pyritic andesite flows and tuffs of the late Eocene to early Oligocene Popof volcanic rocks (Wilson and others, 1995). An ore shoot at the intersection of the Amethyst and Ankle Creek veins has been drilled and trenched It is approximately 300 feet long, 12 feet wide, and extends to a depth of 100 feet. Ore intercepts of three core holes include 16.3 feet grading 0.20 ounce of gold and 0.6 ounce of silver per ton, 31 feet grading 0.20 ounce of gold and 0.4 ounce of silver per ton, and 10 feet grading 0.08 ounce of gold and 0.6 ounce of silver per ton (Anderson and others, 1980). The assays also show up to 1,120 ppm copper, 2,300 ppm lead, 670 ppm zinc, 1,100 ppm arsenic, and 0.64 ppm mercury. Trench samples include 12 feet grading 0.105 ounce of gold and 0.17 ounce of silver per ton, 12 feet grading 0.242 ounce of gold and 0.68 ounce of silver per ton, and 12 feet grading 0.335 ounce of gold and 1.56 ounces of silver per ton (Trujillo and others, 1981). The resource is estimated to be 30,000 tons of ore grading 0.23 ounce of gold and 0.8 ounce of silver per ton. Other trenches and drill holes along the system indicate anomalous, but not sub-ore-grade precious metal values.
Workings: During the period 1980 to 1982 Resource Associates of Alaska and UNC Teton Exploration Drilling Company mapped and sampled the prospect conducted VLF-EM, IP, and magnetometer surveys, core drilled 11 holes for a total of 4,446 feet, and cut 11 trenches. One ore shoot was outlined and evaluated at 30,000 tons grading 0.23 ounce of gold and 0.8 ounce of silver per ton (Trujillo and others, 1981). In 1986 Battle Mountain Exploration Company carried out orientation soil, magnetometer, and VLF surveys over the prospect.
Age: Eocene or younger.
Alteration: The host rocks exhibit weak to strong propylitic and argillic alteration. The propylitic alteration is accompanied by 2 to 5 percent disseminated pyrite.
Reserves: An ore shoot on the prospect contains an estimated 30,000 tons grading 0.23 ounce of gold and 0.8 ounce of silver per ton.
Commodities (Major) - Ag, Au; (Minor) - As, Cu, Hg, Pb, Zn
Development Status: None
Deposit Model: Epithermal gold vein
Commodity List
This is a list of exploitable or exploited mineral commodities recorded at this locality.Mineral List
6 valid minerals.
Regional Geology
This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.
Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org
| Miocene 5.333 - 23.03 Ma ID: 3193007 | Cenozoic sedimentary rocks Age: Miocene (5.333 - 23.03 Ma) Lithology: Sedimentary rocks Reference: Chorlton, L.B. Generalized geology of the world: bedrock domains and major faults in GIS format: a small-scale world geology map with an extended geological attribute database. doi: 10.4095/223767. Geological Survey of Canada, Open File 5529. [154] |
| Eocene - Tertiary 33.9 - 66 Ma ID: 1709301 | Meshik Volcanics and similar rock units Age: Paleogene (33.9 - 66 Ma) Stratigraphic Name: Meshik Volcanics Description: Popof volcanic rocks, only in Shumagin Islands = Meshik Lithology: Igneous Reference: Wilson, F.H., Hults, C.P., Mull, C.G, and Karl, S.M. (compilers). Geologic map of Alaska. doi: 10.3133/sim3340. U.S. Geological Survey Scientific Investigations Map 3340, pamphlet 196. [21] |
Data and map coding provided by Macrostrat.org, used under Creative Commons Attribution 4.0 License
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References
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Anderson, G.L., Butherus, D.L., Fankhauser, R.E., Pray, J.C., Lindberg, P.A., and Hoffman, B.L., 1980, Exploration and evaluation of lands leased from Aleut Native Corporation 1980: Resource Associates of Alaska Report, 84 p, 16 map sheets, various scales. (Report held by the Aleut Corporation, Anchorage, Alaska.).
Peterson, R.J., Lemmers, J., Handverger, P., Gallagher, J., Pilcher, R., East, J., Macleod, T., Bartels. E., 1982, Geology and precious metals potential Unga, Popof, and Korovin Islands, Shumagin Group, Aleutian Chain, Alaska: UNC Teton Exploration Drilling Company report, 127 p., 5 map sheets, various scales. (Report held by the Aleut Corporation, Anchorage, Alaska.).
Trujillo, R.S., Anderson, G., MacLeod, T., Hendrick, K., Farnham, S., Peterson, J., 1981. Exploration and evaluation of the Unga-Popof-Korovan Islands portion of lands leased from Aleut Native Corporation: Resource Associates of Alaska report, 70 p., 38 map sheets, various scales. (Report held by the Aleut Corporation, Anchorage, Alaska.).
Wilson, F.H., Detterman, R.L., Miller, J. W., and Case, J.E., 1995, Geologic map of the Port Moller, Stepovak Bay, and Simeonof Island quadrangles, Alaska: U.S. Geological Survey Miscellaneous Investigation Series Map I-2272, 1 sheet, scale 1:250,000.
