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  3. Mineral Resource Data System (MRDS)

Unnamed (on western Rootok Island)

Occurrence in Alaska, United States with commodities Silver, Gold, Copper, Molybdenum, Zinc
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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. Mineral occurrence model information
  9. Nearby scientific data
  10. Economic information about the deposit and operations
  11. Mining district
  12. Links to other databases
  13. Bibliographic references
  14. General comments
  15. Reporter information

Geologic information

Identification information

Deposit ID 10308478
Record type Site
Current site name Unnamed (on western Rootok Island)

Geographic coordinates

Geographic coordinates: -165.5634, 54.04113 (WGS84)
Relative position This site, anomaly 42 of Christie (1974), is located on the westernmost part of Rootok Island approximately 1/2 mile east of VABM Root. This location is accurate to within 500 feet.

Site location context

Political divisions (FIPS codes)

Aleutians East(Borough)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Unimak A-5(quadrangle 1:63,360 scale)

Akutan Island(quadrangle 1:100,000 scale)

Unimak(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Fox Islands(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
Silver Primary
Gold Primary
Copper Primary
Molybdenum Secondary
Zinc Critical Secondary

Materials information

Materials Type of material
Chalcocite Ore
Chalcopyrite Ore
Malachite Ore
Pyrite Ore
Quartz Gangue
Tourmaline Gangue

Alteration

  • (Local) The rocks exhibit pervasive propylitic alteration consisting of chlorite, epidote, and pyrite. The breccia bodies in the northern area are altered to quartz-sericite-pyrite. Wall rock adjoining the breccias varies from pyritized volcanics to malachite-chalcopyrite-chalcopyrite-bearing porphyritic diorite, whose feldspar phenocrysts are altered to clay.

Mineral occurrence model information

Model code 53
USGS model code 17
Deposit model name Porphyry Cu
Mark3 model number 4

Nearby scientific data

(1) -165.5634, 54.04113
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = At this site the rocks consist of amygdoidal and porphyritic andesites of probable Tertiary or later age. They are cut by diorite dikes or plugs (Christie, 1974). All of the intrusive rocks examined contained pyrite as disseminations and fracture fillings. This occurrence consists of a northern and a southern color anomaly separated by a covered area approximately 1000 feet wide. In the northern area copper minerals occur along a north-facing sea cliff irregularly for 800 feet. The minerals are mainly malachite and minor chalcopyrite and chalcocite, and are sporadically distributed throughout the area. The minerals are mainly in breccia bodies, up to 60 feet in width, consisting of angular and rotated fragments of quartz-sericite-pyrite in a matrix of comminuted fragments and iron oxides. Malachite is present both in the fragments and matrix. One breccia contains 1 to 2 percent tourmaline. Wall rock around the breccias varies from pyritiferous volcanics to malachite-chalcopyrite-chalcocite-bearing diorite. The quartz-sericite-pyrite alteration grades outward to pervasive propylitization marked by epidote and pyrite. The southern color anomaly exhibits pervasive propylitic alteration which grades southward to unaltered volcanics over distance of approximately 3000 feet. . Seventeen rock samples collected by the Aleut-Quintana-Duval JV contained up to 159 ppm copper, 0.46 ppm gold, 6 ppm molybdenum, 2.2 ppm silver, and 120 ppm zinc (Christie, 1974). In 1975 Christie (1976) returned to this site and collected soils and silts and conducted a magnetometer survey of the covered area. This examination revealed strongly altered, biotite-bearing rock containing widely-spaced quartz veins. This material contained up to 790 ppm copper and 0.04 ppm gold.
  • Age = Probably 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 = Christie (1974) conducted reconnaissance geologic mapping and limited sampling. That sampling generally indicated low values of copper and molybdenum and gold values as high as 0.46 ppm and silver values as high 2.2 ppm. Zinc values were moderately anomalous: a number of samples yielded values in the range of 90 to 120 ppm. Although Christie (1974) mentions copper values up to 0.25 percent, his sample data does not support this. Christie (1976) did some additional work in the covered area in 1975, but concluded the area was not worth drilling.

Reference information

Bibliographic references

Comments on the references

  • Primary Reference = Christie, 1974

General comments

Subject category Comment text
Deposit Model Name = Porphyry copper (Cox and Singer, 1986; model 17)
Deposit Other Comments = This site is on land patented by or conveyed to the Aleut Native Corporation.

Reporter information

Type Date Name Affiliation Comment
Reporter 27-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.