Unnamed (Brady Glacier outwash)

Past Producer in Alaska, United States with commodities Gold, Titanium, Zirconium, PGE

Geologic information

Identification information

Deposit ID 10002282
MRDS ID A013186
Record type Site
Current site name Unnamed (Brady Glacier outwash)
Related records 10234006

Geographic coordinates

Geographic coordinates: -136.61208, 58.34971 (WGS84)
Relative position This placer deposit is at the terminus of Brady Glacier at Taylor Bay; it extends southerly onto broadly-exposed tide flats. The coordinate location is the approximate center of the glacier front as drawn on the Mt. Fairweather B-2 quadrangle, which was mapped from aerial photographs taken in 1948. The placer deposits occur in an arcuate zone about 3 miles long south of the glacier. Small, transient placer deposits could occur throughout the broad tide flats south of the terminus of the glacier.
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Gold Primary
Titanium Primary
Zirconium Primary
PGE Secondary

Comments on the commodity information

  • Ore Material = PGE
  • Ore Material = Gold (native)
  • Ore Material = Gold (native)

Materials information

Materials Type of material
Gold Ore
Ilmenite Ore
Zircon Ore

Host and associated rocks

  • Host or associated Host
    Rock type Unconsolidated Deposit > Till
    Stratigraphic age (youngest) Holocene
  • Host or associated Host
    Rock type Unconsolidated Deposit > Glacial Sediment

Nearby scientific data

(1) -136.61208, 58.34971

Comments on the geologic information

  • Geologic Description = Brady Glacier occupies a major north-northwest-aligned boundary between Paleozoic strata intruded by granitic rocks of Cretaceous age on the east and rocks of Cretaceous and Tertiary age to the west (Brew and others, 1978). The Brady Glacier nickel-copper deposit (MF003) is in the western province and within the drainage basin of the glacier. Glacial erosion of the sulfide and oxide deposits of the Crillon-LaPerouse layered mafic intrusion, the host of the Brady Glacier deposit, would furnish titanium and PGEs to the glacial outflow. Gold deposits similar to the LeRoy mine (MF022) could exist in the Cretaceous rocks in the eastern terrane.? Gold, in extremely fine-grained form, ilmenite, PGEs, and zircon locally are concentrated in transient placers at the front of the glacier.? Placer samples collected from the outwash fan by the U.S. Bureau of Mines contained as much as 0.15 ppm gold (Kimball and others, 1978) and 6.15 percent titanium (Foley and others,1995).
  • Age = Holocene.

Economic information

Economic information about the deposit and operations

Development status Past Producer
Commodity type Metallic

Comments on exploration

  • Status = Inactive

Mining district

District name Juneau

Comments on the workings information

  • Workings / Exploration = Small, transient placers on the outwash plain were worked during the early years of the twentieth century (Rossman, 1963, B 1121-K, p. K51-52). The U.S. Bureau of Mines (Kimball and others, 1978, p. C126) detected gold content in stream-sediment-type samples of up to 0.15 ppm (0.004 oz/ton) along with traces of silver, copper, cobalt, and nickel. The gold is extremely fine-grained, but local concentrations could have been rich. The gold is so fine that recovery is difficult.? Foley and others (1995, sample no. 319) determined that ilmenite (titanium) and zircon (zirconium) were present in one sample in anomalous amounts. The sample contained 4.95 percent and 6.15 percent titanium, respectively, in a head split and a spiral concentrate. Zirconium was reported as 720 ppm in the head split and 1084 ppm in the spiral concentrate.

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A013186
USGS Alaska Resource Data File ARDF MF088

Bibliographic references

  • Deposit

    Rossman, Darwin, 1963, Geology of the eastern part of the Mount Fairweather quadrangle, Glacier Bay, Alaska: U.S. Geological Survey Bulletin 1121-K, p. K1-K57.

  • 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.

  • Deposit

    Foley, J.Y., La Berge, R.D., Grosz, A.E., Oliver, F.S., and Hirt, W.C., 1995, Onshore titanium and related heavy mineral investigations in the eastern Gulf of Alaska region, southern Alaska: U.S. Bureau of Mines Open-File Report 10-95, 125 p.

  • Deposit

    Cobb, E.H., 1972, Metallic mineral resources map of the Mount Fairweather quadrangle, AK: U.S. Geological Survey Miscellaneous Field Study Map MF-436, 1 sheet, scale 1:250,000.

Comments on the references

  • Primary Reference = Kimball and others, 1978

General comments

Subject category Comment text
Deposit Model Name = Placer: Low-grade glacial outwash reworked on tidal flat.
Deposit Other Comments = the placer sites are in Glacier Bay National Park and Preserve.

Reporter information

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