Windy Bay

Occurrence in Alaska, United States with commodities Copper, Molybdenum, Gold, Lead, Zinc

Geologic information

Identification information

Deposit ID 10001672
MRDS ID A012450
Record type Site
Current site name Windy Bay

Geographic coordinates

Geographic coordinates: -158.78134, 56.14234 (WGS84)
Relative position This site is approximately 2 miles west of the head of the north arm of Windy Bay and includes the headwaters of streams draining into that head of the bay (Cox and others, 1981, locality 9). The site is accurate as plotted.
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Copper Primary
Molybdenum Primary
Gold Secondary
Lead Secondary
Zinc Secondary

Materials information

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

Alteration

  • (Local) Alteration in the intrusive consists of local zones containing chlorite, epidote, and secondary biotite. The sediments near the intrusive contact have been hornfelsed, silicified, and contain chlorite and secondary biotite.

Mineral occurrence model information

Model code 53
USGS model code 17
Deposit model name Porphyry Cu
Mark3 model number 4
Model code 78
USGS model code 20c
Deposit model name Porphyry Cu-Au
Mark3 model number 34
Model code 79
USGS model code 21a
Deposit model name Porphyry Cu-Mo
Mark3 model number 2

Host and associated rocks

  • Host or associated Associated
    Rock type Sedimentary Rock > Clastic Sedimentary Rock > Shale > Black Shale
    Rock unit name Naknek Formation;Naknek Formation
    Rock description Naknek Formation;Naknek Formation
  • Host or associated Host
    Rock type Sedimentary Rock > Clastic Sedimentary Rock > Siltstone
    Rock unit name Naknek Formation;Naknek Formation;Naknek Formation;
    Rock description Naknek Formation;Naknek Formation;Naknek Formation;

Nearby scientific data

(1) -158.78134, 56.14234

Comments on the geologic information

  • Geologic Description = The geologic setting at this site consists of a quartz diorite stock which has intruded sedimentary units of the Jurassic Naknek Formation (Fields, 1977). These units include grits, graywacke, siliceous siltstone, and black shale.? A discontinuous color anomaly is present along the inferred contact zone (Fields, 1977). The sediments near the contact have been hornfelsed and contain pyrrhotite, pyrite, rare chalcopyrite, and magnetite as disseminations and as veinlet and fracture fillings. Total sulfide content is 1-5 percent. Sulfides occur up to 1000 feet from the contact.? the sulfide content of the intrusive is 1 percent or less. Chalcopyrite is present on fracture surfaces and in quartz-chlorite and pyrite veinlets. These strike approximately N 25 W and cover an area of 1000 by 4000 feet.? Samples of the mineralized intrusive contained up to 424 ppm copper, 0.13 ppm gold, 32 ppm lead, 25 ppm molybdenum, and 9 ppm zinc (Fields, 1977).? the intrusive exhibits local chloritization along with scattered patches of epidote and secondary biotite. The hornfelsed sediments have been silicified and contain secondary biotite and minor chlorite.
  • Age = Tertiary.

Economic information

Economic information about the deposit and operations

Development status Occurrence
Commodity type Metallic

Comments on exploration

  • Status = Inactive

Mining district

District name Alaska Peninsula

Comments on the workings information

  • Workings / Exploration = Bear Creek Mining Company briefly explored this site during the period 1975-1976. The few samples collected contained up to 424 ppm copper, 0.13 ppm gold, 32 ppm lead, 25 ppm molybdenite, and 9 ppm zinc (Fields, 1977).? Resource Associates of Alaska briefly sampled this occurrence in 1979 (Anderson and others, 1979).

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A012450
USGS Alaska Resource Data File ARDF CG012

Bibliographic references

  • Deposit

    Fields, E.D., 1977, 1976 Annual report: Alaska search, Chignik area-Bristol Bay region: Bear Creek Mining Company, 44 p., 22 map sheets. (Report held by the Aleut Corporation, Anchorage, Alaska.)

  • Deposit

    Anderson, G.D., Fitch, G.M., Lappie, D.W., Lindberg, P.A., and Fankhauser, R.E., 1979, Exploration and evaluation of Bristol Bay Native Corporation Lands, Vol. II, Book 1: prepared for Houston Oil and Minerals Company by Resource Associates of Alaska, 78 p. (Report held by Alaska Earth Science, Anchorage, Alaska.)

  • Deposit

    Cox, D.P., Detra, D.E., and Detterman, R.L., 1981, Mineral resource maps of the Chignik and Sutwik Island quadrangles, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF- 1053-K, 2 map sheets, scale 1:250,000.

Comments on the references

  • Primary Reference = Fields, 1977

General comments

Subject category Comment text
Deposit Model Name = Porphyry copper; porphyry copper-gold; porphyry copper-molybdenum (Cox and Singer, 1986; models 17, 20c, 21a)
Deposit Model Number = 17, 20c, 21a
Deposit Other Comments = This site is partially on land selected by the Bristol Bay Native Corporation. The remainder is within the Alaska Peninsula National Wildlife Refuge.

Reporter information

Type Date Name Affiliation Comment
Reporter 08-FEB-2000 S.H. Pilcher U.S. Geological Survey