Boulder Bay

Occurrence in Alaska, United States with commodity Gold

Geologic information

Identification information

Deposit ID 10003283
MRDS ID A106026
Record type Site
Current site name Boulder Bay

Geographic coordinates

Geographic coordinates: -167.73237, 53.32908 (WGS84)
Relative position Northeast side of Umnak Pass between Boulder Bay and Paso Point on Unalaska Island. Anomaly no. 46 of Christie (1974).
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Geographic areas

Country State
United States Alaska


Commodity Importance
Gold Primary

Materials information

Materials Type of material
Pyrite Ore
Chlorite Gangue
Epidote Gangue


  • (Local) Propylitic alteration as evidenced by the presense of chlorite and epidote.

Mineral occurrence model information

Model code 105
USGS model code 25a-d
Deposit model name Epithermal vein, generic
Mark3 model number 119

Nearby scientific data

(1) -167.73237, 53.32908

Comments on the geologic information

  • Geologic Description = A small 1,500 ft (450 m) long north-south trending color anomaly is developed in hornfelsed sedimentary, and pyroclastic volcanic rocks of the Unalaska Formation (see Drewes and others, 1961) cut by north-south trending monzonite and feldspar porphyry dikes. Disseminated and fracture-controlled pyrite occurs in both dike and wall rocks. Minor quartz veining is noted in the description of the occurrence as is weak fracturing.
  • Age = Miocene or younger

Economic information

Economic information about the deposit and operations

Development status Occurrence
Commodity type Metallic

Comments on exploration

  • Status = Inactive

Mining district

District name Aleutians

Comments on the workings information

  • Workings / Exploration = Brief reconnaissance mapping and 4 soil or silt samples. Copper, molybdenum, zinc and silver were low, however a few samples showed gold to 0.20 ppm.

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A106026
USGS Alaska Resource Data File ARDF UN032

Bibliographic references

  • Deposit

    Drewes, Harold, Fraser, G.D., Snyder, G.L., and Barnett, H.F., Jr., 1961, Geology of Unalaska Island and adjacent insular shelf, Aleutian Islands, Alaska: U.S. Geological Survey Bulletin 1028-S, p. 583-676.

  • 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    Christie, J.S., 1974, Aleut-Quintana-Duval 1974 joint venture, final report: Unpublished Quintana Minerals Corporation report, 24 p., 3 appendices, 2 maps.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.)

Comments on the references

  • Primary Reference = Christie, 1974

General comments

Subject category Comment text
Deposit Model Name = Epithermal gold vein

Reporter information

Type Date Name Affiliation Comment
Reporter 06-MAY-1994 Damon Bickerstaff U.S. Geological Survey
Reporter 06-MAY-1994 F.H. Wilson U.S. Geological Survey