1. Mineral Resources
  2. Online Spatial Data
  3. Mineral Resource Data System (MRDS)

Unnamed (on southeast coast of Nagai Island)

Occurrence in Alaska, United States with commodities Gold, Arsenic
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Sections on this page
  1. Identification information
  2. Geographic coordinates
  3. Site location context
  4. Geographic areas
  5. Commodities
  6. Materials information
  7. Alteration
  8. Nearby scientific data
  9. Economic information about the deposit and operations
  10. Mining district
  11. Links to other databases
  12. Bibliographic references
  13. General comments
  14. Reporter information

Geologic information

Identification information

Deposit ID 10308261
Record type Site
Current site name Unnamed (on southeast coast of Nagai Island)

Geographic coordinates

Geographic coordinates: -160.11739, 54.97424 (WGS84)
Relative position This site is on the southeast coast of Nagai Island approximately 2 miles northeast of Saddler Peak and includes mineral showings at sea level and in the adjacent sea-cliffs. Location is accurate to within a few hundred feet.

Site location context

Political divisions (FIPS codes)

Aleutians East(Borough)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Simeonof Island D-4(quadrangle 1:63,360 scale)

Shumagin Islands S(quadrangle 1:100,000 scale)

Simeonof Island(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Cold Bay(hydrologic unit)

Aleutian Islands(hydrologic accounting unit)

Southwest(hydrologic subregion)

Alaska(hydrologic region)

Federal lands

Alaska Maritime National Wildlife Refuge(National Wildlife Refuge)

National Wildlife Refuge FWS(Type of land area)

FWS(Federal land areas administered by FWS)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Gold Primary
Arsenic Critical Secondary

Materials information

Materials Type of material
Arsenopyrite Ore
Gold Ore
Pyrite Ore
Quartz Gangue

Alteration

  • (Local) Sedimentary country rocks are silicified and pyritic adjacent to the sills. Hydrothermal breccia zone in sills. Color anomaly about 3 miles north of site.

Nearby scientific data

(1) -160.11739, 54.97424
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = At this mineral occurrence two Tertiary quartz diorite sills intrude siltstone and sandstone of the Cretaceous Shumagin Formation (Ellis and Apel, 1989). The strata strike northwest and dip 20-50 degrees to the southwest. They are silicified and pyritic adjacent to the contact. The sills crop out along the sea cliffs and beach for approximately 1600 feet. Gold is present in the sills in quartz-arsenopyrite veins and stockworks thought to be associated with northwest-trending faults and shear zones. Gold also occurs in the altered rocks adjacent to the sills and in a 100-foot wide hydrothermal breccia zone. . In 1989 Battle Mountain Exploration Company collected 61 rock-chip samples, 22 of which contained >100 ppb gold (Ellis and Apel, 1989). Fifteen samples contained 100 to 499 ppb gold, 5 contained 500 to 999 ppb gold, and 2 had >1ppm ppm gold (up to 6.55 ppm). Elsewhere on the island they also obtained scattered pan concentrate and rock samples anomalous in arsenic, gold, and mercury. Free gold was also noted on the beach at Saddlers Mistake and in several streams draining the area. Anomalous gold was also found over a 1/2 mile area associated with a color anomaly located in steep cliffs approximately 3 miles north of this site. Numerous gold anomalies were detected on the north part of the island by the U.S. Geological Survey (Frisken and Kelly, 1992).
  • Age = Tertiary.

Economic information about the deposit and operations

Development status Occurrence

Comments on exploration

  • Status = Inactive

Mining district

District name Aleutian Islands

Comments on the workings information

  • Workings / Exploration = In 1989 Battle Mountain Exploration mapped and sampled this mineral occurrence. Of 61 rock-chip samples collected 22 contained >100 ppb gold. The highest value obtained was 6.55 ppm gold (Ellis and Apel, 1989). The U.S. Geological Survey mapped and geochemically sampled in the Simeonof Island quadrangle in the late 1980's (Wilson and others, 1991; Frisken, 1992).

Reference information

Bibliographic references

  • Deposit

    Ellis, W.T., and Apel, R.A., 1989, Unga/Alaska Peninsula 1989 final report: Battle Mountain Exploration Company report, 41 p., 28 map sheets at various scales. (Report held by the Aleut Corporation, Anchorage, Alaska.)

  • Deposit

    Frisken, J.G., 1992, Interpretation of reconnaissance geochemical data from the Port Moller, Stepovak Bay, and Simeonof Island quadrangles, Alaska Peninsula, Alaska: U.S. Geological Survey Bulletin 1968, 47 p., 3 map sheets, scale 1:250,000.

  • Deposit

    Frisken, J.G., and Kelly, D.L., 1992, Maps showing the distribution of gold determined in various sample media collected from Port Moller, Stepovak Bay, and Simeonof Island quadrangles, Alaska Peninsula, Alaska: U.S. Geological Survey Map MF-2155-D, 2 map sheets, scale 1:250,000.

  • Deposit

    Wilson, F.H., Detterman, R.L., and Harris, E.E., 1991, Generalized geologic map of Port Moller, Stepovak Bay, and Simeonof Island quadrangles, Alaska Peninsula, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-2155-A, 1 sheet, scale 1:250,000.

Comments on the references

  • Primary Reference = Ellis and Apel, 1989

General comments

Subject category Comment text
Deposit Other Comments = This site is located on land selected by the Aleut Native Corporation.

Reporter information

Type Date Name Affiliation Comment
Reporter 24-JAN-00 S.H. Pilcher U.S. Geological Survey

Beyond USGS

Supplemental information added by qvyshift.com. Not part of the original USGS MRDS record.

Maps centered on this site

Authoritative Alaska resources

These are landing pages for further research — the state agencies don't currently expose per-mine deep links.