Unnamed (western Mitrofania Island)

Occurrence in Alaska, United States with commodities Silver, Gold, Lead, Zinc, Arsenic, Bismuth, Copper, Antimony

Geologic information

Identification information

Deposit ID 10308222
Record type Site
Current site name Unnamed (western Mitrofania Island)

Geographic coordinates

Geographic coordinates: -158.88243, 55.84727 (WGS84)
Relative position This site is located on the west shore of Mitrofania Island, 0.6 mile west-northwest of the top of hill 1660. It is referred to as SBRGX-44 in Wilson and others (1988, locality 18). The location is accurate to within 2,500 feet.
(click for info)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Silver Primary
Gold Primary
Lead Primary
Zinc Primary
Arsenic Secondary
Bismuth Secondary
Copper Secondary
Antimony Secondary

Materials information

Materials Type of material
Pyrite Ore
Calcite Gangue
Quartz Gangue

Alteration

  • (Local) Silicification.

Mineral occurrence model information

Model code 85
USGS model code 22c
Deposit model name Polymetallic veins
Mark3 model number 46

Nearby scientific data

(1) -158.88243, 55.84727

Comments on the geologic information

  • Geologic Description = This occurrence is in an area mapped as undivided Tertiary volcanic rocks (Wilson and others, 1995). Small plutons of Miocene or Pliocene granodiorite to quartz diorite crop out a few miles to the north and south of the occurrence (Wilson and others, 1995). At this site, fractured and silicified volcanic flows are cut by numerous quartz-calcite veinlets as much as 2 inches thick, which fill the fracture zones (Wilson and others, 1988). Some veinlets carry as much as 80 to 90 percent pyrite and other, unidentified, sulfides. Rock samples collected by the U.S. Geological Survey contained 10 ppm or less gold, and as much as 500 ppm antimony, 26,000 ppm arsenic, 1,500 ppm copper, 300 ppm lead, 50 ppm silver, and 10,000 ppm or more zinc (Angeloni and others, 1985; Wilson and others, 1988). Bismuth is also reported in some of the analyses.
  • Ore Material = unidentified sulfides
  • Age = Tertiary.

Economic information

Economic information about the deposit and operations

Development status Occurrence

Comments on exploration

  • Status = Inactive

Mining district

District name Alaska Peninsula

Comments on the workings information

  • Workings / Exploration = Rock samples 84AGe10-16 collected by the U.S. Geological Survey in the mid-1980's, contained 10 ppm or less gold, and as much as 500 ppm antimony, 26,000 ppm arsenic, 1,500 ppm copper, 300 ppm lead, 50 ppm silver, and greater than 10,000 ppm zinc (Angeloni and others, 1985; Wilson and others, 1988). Bismuth is also reported in some of the analyses.

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Alaska Resource Data File ARDF SB018

Bibliographic references

  • Deposit

    Angeloni, L.M., Wilson, F.H., and Sutlet, S., 1985, Map and tables showing preliminary rock geochemical data, Port Moller, Stepovak Bay, and Simeonof Island quadrangles, Alaska: U.S. Geological Survey Open-File Report 85-470, 179 p., 1 map sheet, scale 1:250,000.

  • Deposit

    Arbogast, B.F., Bailey, E.A., and Frisken, J.G., 1987, Analytical results and sample locality maps of stream sediment, heavy-mineral-concentrate, and rock samples from the Port Moller, Stepovak Bay, and Simeonof island quadrangles, Alaska: U.S. Geological Survey Open-File Report 87-502, 122 p., 2 sheets, scale 1:250,000.

  • Deposit

    Wilson, F.H., White, W.H., and DuBois, G.D., 1988, Brief descriptions of mines, prospects, and mineral occurrences in the Port Moller and Stepovak Bay quadrangles, Alaska Peninsula: U.S. Geological Survey Open-File Report 88-666, 128 p., scale 1:250,000.

  • 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 = Wilson and others, 1988

General comments

Subject category Comment text
Deposit Model Name = Polymetallic veins (Cox and Singer, 1986; model 22c).
Deposit Other Comments = This site is located on land selected by the Bristol Bay Native Corporation.

Reporter information

Type Date Name Affiliation Comment
Reporter 08-NOV-00 S.H. Pilcher U.S. Geological Survey