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

Unnamed (on Idaho Ridge)

Occurrence in Alaska, United States with commodities Molybdenum, Tungsten, Silver, Copper
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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 10307819
Record type Site
Current site name Unnamed (on Idaho Ridge)

Geographic coordinates

Geographic coordinates: -136.2601, 58.90073 (WGS84)
Relative position Occurrence is at an elevation of about 2900 feet on Idaho Ridge about 0.1 mile east of hill 2994 (section 21, T. 34 S., R 55 E., of the Copper River Meridian). It is located within 0.05 mile accuracy. The location of the site is shown on figure C65 of Kimball and others (1978).

Site location context

Political divisions (FIPS codes)

Hoonah-Angoon(Census area)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Mount Fairweather D-1(quadrangle 1:63,360 scale)

Juneau NW(quadrangle 1:100,000 scale)

Mount Fairweather(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Glacier Bay(hydrologic unit)

Northern Southeast Alaska(hydrologic accounting unit)

Southeast Alaska(hydrologic subregion)

Alaska(hydrologic region)

Federal lands

Glacier Bay National Park(National Park)

National Park NPS(Type of land area)

NPS(Federal land areas administered by NPS)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Molybdenum Primary
Tungsten Critical Primary
Silver Secondary
Copper Secondary

Materials information

Materials Type of material
Chalcopyrite Ore
Molybdenite Ore
Scheelite Ore
Quartz Gangue

Alteration

  • (Local) Epidote along quartz veins.

Nearby scientific data

(1) -136.2601, 58.90073
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = The Idaho Ridge area is underlain mostly by foliated granitic rock of Cretaceous age, covered locally by deep glacial moraine (MacKevett and others, 1971; Brew and others, 1978). At the site investigated by the U.S. Bureau of Mines widely distributed fractures in granitic rock had propylitic alteration (epidote); the intrusive was also cut by unmineralized breccia zones (Kimball and others, 1978; p. C310-312). A float rock sample (75CN108A) collected near this area by the U.S. Geological Survey in 1975 contained 700 ppm molybdenum, 300 ppm tungsten, 100 ppm bismuth, and 10 ppm silver (Brew and others, 1978, table B-8). In follow-up activity conducted by the U.S. Bureau of Mines in 1976, significant mineralization was found in narrow (to 0.15 foot) quartz-sulfide veins, but not in chip samples collected over a 5 to 13 foot width (Kimball and others, 1978, table C56): Selected samples of thin quartz-sulfide veinlets contained as much as 240 ppm copper, 500 ppm tungsten, 300 ppm molybdenum, and 15 ppm silver.
  • Ore Material = 'sulfides'
  • Age = Cretaceous or younger. Veins post-date foliated granitic intrusion of Cretaceous age.

Economic information about the deposit and operations

Development status Occurrence

Comments on exploration

  • Status = Inactive

Mining district

District name Juneau

Comments on the workings information

  • Workings / Exploration = No workings A sample of mineralized float (USGS No. 75CN108A--Brew and others, 1978, table B-8) contained 700 ppm molybdenum, 300 ppm tungsten, 100 ppm Bi, and 10 ppm silver. In 1976, the U.S. Bureau of Mines found thin quartz-sulfide veinlets at two locations on Idaho Ridge that contained as much as 500 ppm tungsten, 300 ppm molybdenum, 15 ppm silver, and 240 ppm copper (Kimball and others, 1978, p. C310-312). The Bureau suggested that prospecting around the margins of the host intrusive could reveal better mineralized zones.

Reference information

Bibliographic references

  • Deposit

    MacKevett, E.M., Jr., Brew, D.A., Hawley, C.C., Huff, L.C., and Smith, J.G., 1971, Mineral resources of Glacier Bay National Monument, Alaska: U.S. Geological Survey Professional Paper 632, 90 p., 12 plates, scale 1:250,000.

  • Deposit

    Brew, D.A., Johnson, B.R., Grybeck, D., Griscom, A., Barnes, D.F., Kimball, A.L., Still, J.C., and Rataj, J.L., 1978, Mineral resources of the Glacier Bay National Monument Wilderness Study Area, Alaska: U.S. Geological Survey Open-File Report 78-494, 670 p.

  • Deposit

    Kimball, A.L., Still, J.C., and Rataj, J.L., 1978, Mineral resources, in Brew, D. A., and others, Mineral resources of the Glacier Bay National Monument wilderness study area, Alaska: U.S. Geological Survey Open-File Report 78-494, p. C1-C375.

Comments on the references

  • Primary Reference = Kimball and others, 1978

General comments

Subject category Comment text
Deposit Model Name = Low-grade porphyry molybdenum-tungsten deposit.
Deposit Other Comments = Veins found to date are too thin to be of economic interest, but anomalous geochemical samples suggest more prospecting of the area would be justified (Kimball and others, 1978, p. C310-312, including fig. C65). The site is in Glacier Bay National Park and Preserve.

Reporter information

Type Date Name Affiliation Comment
Reporter 15-APR-99 Hawley, C.C. Hawley Resource Group

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.