Unnamed (between Balboa Bay and Dorenoi Bay)

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

Geologic information

Identification information

Deposit ID 10308102
Record type Site
Current site name Unnamed (between Balboa Bay and Dorenoi Bay)

Geographic coordinates

Geographic coordinates: -160.49244, 55.61924 (WGS84)
Relative position This site is located on the Alaska Peninsula and represents an area of over 24 square miles between Balboa and Dorenoi Bays (Christie, 1974, color anomaly 76; MacKevett and Holloway, 1977, locality 21; Wilson and others, 1988, locality 21). The site location is plotted near the center of the area, in the SE1/4 of sec. 5, T. 53 S., R. 73 W., of the Seward Meridian.
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Geographic areas

Country State
United States Alaska

Commodities

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

Materials information

Materials Type of material
Arsenopyrite Ore
Chalcopyrite Ore
Galena Ore
Gold Ore
Magnetite Ore
Molybdenite Ore
Pyrite Ore
Sphalerite Ore
Tetrahedrite Ore
Barite Gangue
Calcite Gangue
Quartz Gangue

Alteration

  • (Local) All volcanic units exhibit pervasive propylitization. Silicification is present along mineralized shears and in zones of fracturing and brecciation. Argillization is associated with silica-flooded areas.

Mineral occurrence model information

Model code 53
USGS model code 17
Deposit model name Porphyry Cu
Mark3 model number 4
Model code 79
USGS model code 21a
Deposit model name Porphyry Cu-Mo
Mark3 model number 2
Model code 85
USGS model code 22c
Deposit model name Polymetallic veins
Mark3 model number 46

Nearby scientific data

(1) -160.49244, 55.61924

Comments on the geologic information

  • Geologic Description = This site represents a 24-square-mile color anomaly (Christie. 1974, number 76) that contains numerous areas of mineralization. The anomaly occurs in rocks mapped as Miocene volcanics (Wilson and others, 1995) which here include andesite to dacite tuff, breccia, agglomerate, tuffaceous sedimentary rocks, some flow rocks, and minor sandstone and shale. These have been intruded by diorite stocks and rhyolite dikes. The anomaly is caused by the oxidation of as much as 5 percent pyrite disseminated in propylitically altered andesite. An Aleut-Quintana-Duval joint venture in 1975 mapped, sampled, conducted a magnetic survey, and drilled two holes on a narrow zone of copper-molybdenum mineralization in fine-grained diorite containing as much as 0.25 percent copper (Christie, 1976). The diorite contains chalcopyrite, magnetite, pyrite, and quartz in fractures. It exhibits pervasive propylitic alteration. The mineralized zone trends southeast beneath a large covered area in which the holes were drilled. These drill holes intersected as much as 183 feet of oxidized capping and bottomed in weakly mineralized diorite containing 5 to 10 percent pyrite and as much as 0.015 percent copper. Resource Associates of Alaska explored the color anomaly for precious metals in 1979, 1980, and 1983. They mapped, sampled, and hand trenched and discovered many discontinuous, narrow zones of silicification and brecciation that appear to be associated with regional faults (Anderson and others, 1980). They also noted areas of strongly developed stockwork veining. Some of the altered zones contain narrow quartz-barite or quartz-carbonate veins with metal values of as much as 4.45 ppm gold, 500 ppm silver, 23,975 ppm copper, 30,000 ppm lead, and 14,700 ppm zinc. Mercury and antimony are also present (Trujillo and others, 1983). During this period of exploration three other areas of silica-flooded rock were discovered in a variety of host rocks and structural settings. These occurrences are subhorizontal bodies as much as 200 feet thick and 2,000 feet long. Some contain iron oxides and pyrite as disseminatioins and as fracture fillings. Silica replacement of the hostrocks ranges from partial to total. Zones of intense argillization tend to partially surround the silicified zones, especially at their base (Trujillo and others, 1983). Base metal sulfides occur in the silicified rocks in voids, in quartz veins, and in gouge and breccia zones. Gold values are generally low; a few of the quartz veins contain as much as 0.28 ppm gold and 1.3 ppm silver.
  • Age = Miocene or younger.

Economic information

Economic information about the deposit and operations

Development status Prospect

Comments on exploration

  • Status = Inactive

Mining district

District name Alaska Peninsula

Comments on the workings information

  • Workings / Exploration = In 1975 an Aleut-Quintana-Duval joint venture sampled, mapped, made magnetic surveys, and drilled two core holes for a total of 1,503 feet. Resource Associates of Alaska explored the area in 1979, 1980, and 1983. They did detailed mapping, collected some 2,000 samples for assay, and hand dug trenches. Freeport Exploration Company briefly mapped and sampled the area in 1984. The U.S. Geological Survey sampled the prospect in the mid-1980's.

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Alaska Resource Data File ARDF PM026

Bibliographic references

  • Deposit

    Christie, J.S., 1974, Aleut-Quintana-Duval 1974 joint venture, final report: Unpublished Quintana Minerals Corporation report, 24 p., 3 appendices, 2 maps. (Report held by the Aleut Corporation, Anchorage, Alaska.)

  • Deposit

    Butherus, D.L, Gressitt, E.E., Pray, J., Corner, N.G., Lindberg, P.H., and Fankhauser, R.E., 1979, Exploration and evaluation of the Aleut Native Corporation lands; Volume III: Resource Associates of Alaska, 69 p. 90 sheets, various sacales. (Report held by the Aleut Native Corporation, Anchorage, Alaska.)

  • 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., Tapper, C.J., Alvarez, T.J., Porterfield, Ben, and Toupe, W.M., 1982, Exploration and evaluation of precious metal potential of portions of Aleut Corporation lands, southwest Alaska 1982: Unpublished Resource Associates of Alaska report, 91 p, 33 mpas, various scales. (Report held by the Aleut Corporation, Anchorage, Alaska.)

  • Deposit

    Trujillo, R.S., Farnham, S., and Anderson, G.,1983, Exploration and evaluation of precious metal potential of the Aleut Corporation 14(h)8 lands, southwest Alaska: Resource Associates of Alaska report, 25 p., 11 map sheets, various scales. (Report held by the Aleut Corporation, Anchorage, Alaska.)

  • Deposit

    Freeport Exploration Company, 1985, 1984 report of activities, Canoe Bay joint venture: Freeport Exploration Company, 25 p. (Report held by the Aleut Corporation, Anchorage, Alaska.)

  • 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.

  • Deposit

    Christie, J.S., 1976, Aleut-Quintana-Duval joint venture, 1975. Report on drill programs at the Tarasof and San Diego prospects and additional exploration Rootok Island and Unalaska Island: Quintana Minerals Report, 20 p., 11 map sheets, various scales. (Report held by the Aleut Corporation, Anchorage, Alaska.)

  • Deposit

    MacKevett, E.M., Jr., and Holloway, C.D., 1977, Map showing metalliferous mineral deposits in the western part of southern Alaska: U.S. Geological Survey Open-File Report 77-169-F, 38 p., 1 sheet, scale 1:1,000,000.

Comments on the references

  • Primary Reference = Anderson and others, 1980

General comments

Subject category Comment text
Deposit Model Name = Epithermal gold veins, Porphyry Cu, Porphyry Cu-Mo, Polymetallic veins (Cox and Singer, 1986; models 17, 21a, 22c)
Deposit Model Number = 17, 21a, 22c
Deposit Other Comments = This prospect is located on land selected or patented by, or interim-conveyed to, the Aleut Corporation.

Reporter information

Type Date Name Affiliation Comment
Reporter 08-JAN-01 S.H. Pilcher U.S. Geological Survey