Amethyst

Prospect in Alaska, United States with commodities Silver, Gold, Arsenic, Copper, Mercury, Lead, Zinc

Geologic information

Identification information

Deposit ID 10308693
Record type Site
Current site name Amethyst

Geographic coordinates

Geographic coordinates: -160.65641, 55.18723 (WGS84)
Relative position 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.
(click for info)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Silver Primary
Gold Primary
Arsenic Secondary
Copper Secondary
Mercury Secondary
Lead Secondary
Zinc Secondary

Materials information

Materials Type of material
Chalcopyrite Ore
Galena Ore
Gold Ore
Pyrite Ore
Sphalerite Ore
Quartz Gangue

Alteration

  • The host rocks exhibit weak to strong propylitic and argillic alteration. The propylitic alteration is accompanied by 2 to 5 percent disseminated pyrite.

Nearby scientific data

(1) -160.65641, 55.18723

Comments on the geologic information

  • Geologic Description = 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.
  • Age = Eocene or younger.

Economic information

Economic information about the deposit and operations

Development status Prospect
Commodity type Metallic

Comments on exploration

  • Status = Inactive

Mining district

District name Alaska Peninsula

Comments on the reserve resource information

  • 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.

Comments on the workings information

  • Workings / Exploration = 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.

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Alaska Resource Data File ARDF PM092

Bibliographic references

  • Deposit

    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.)

  • Deposit

    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.)

  • Deposit

    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.)

  • Deposit

    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 map sheet, scale 1:250,000.

Comments on the references

  • Primary Reference = Trujillo and others, 1981

General comments

Subject category Comment text
Deposit Model Name = Epithermal gold vein
Deposit Other Comments = This prospect is located on land patented by, or interim-conveyed to, the Aleut Corporation.

Reporter information

Type Date Name Affiliation Comment
Reporter 03-FEB-2001 S.H. Pilcher U.S. Geological Survey