Unnamed (upper Dundas Bay)

Occurrence in Alaska, United States with commodities Silver, Molybdenum, Tin, Tungsten, Gold, Bismuth

Geologic information

Identification information

Deposit ID 10002279
MRDS ID A013183
Record type Site
Current site name Unnamed (upper Dundas Bay)
Related records 10112647

Geographic coordinates

Geographic coordinates: -136.54208, 58.45972 (WGS84)
Relative position The site consists of an area near the head of Dundas Bay (sections 29-30, T. 39 S., R. 54 E., of the Copper River Meridian). The coordinates are the approximate location of a metallized skarn; they are at the approximate midpoint of sections 29 and 30.
(click for info)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Silver Primary
Molybdenum Primary
Tin Primary
Tungsten Primary
Gold Secondary
Bismuth Secondary

Comments on the commodity information

  • Ore Material = unknown Bi-bearing mineral
  • Ore Material = unknown Bi-bearing mineral

Materials information

Materials Type of material
Cassiterite Ore
Molybdenite Ore
Powellite Ore
Scheelite Ore
Diopside Gangue
Epidote Gangue
Garnet Gangue

Alteration

  • (Local) Contact metasomatism, development of skarn.

Mineral occurrence model information

Model code 43
USGS model code 14b
Deposit model name Sn skarn
Model code 80
USGS model code 21b
Deposit model name Porphyry Mo, low-F

Host and associated rocks

  • Host or associated Host
    Rock type Sedimentary Rock > Carbonate > Limestone

Nearby scientific data

(1) -136.54208, 58.45972

Comments on the geologic information

  • Geologic Description = The country rocks in the area of this occurrence consist mainly of sedimentary rocks of Paleozoic age and sedimentary and granitic intrusive rocks of Paleozoic age. The area is east of the major fault that separates Mesozoic from Paleozoic terrane in southwest Glacier Bay National Park and Preserve (Brew and others, 1978). A granitic (granodiorite ) pluton of Tertiary age invades older sedimentary and granitic rock, including pendants of Paleozoic limestone, partly converting the limestone to skarn. ? This occurrence encompasses an area characterized by anomalous amounts of molybdenum, tin, and tungsten in stream-sediment samples, rock samples, and in outcropping metaliferous skarn. The anomalous area is elongated east-west on the contact between Tertiary granodiorite to the south and Cretaceous and older sedimentary and igneous rocks to the north. The skarn, mainly developed in limestone of Paleozoic age, contains powellite and as much as 150 ppm tin , 200 ppm bismuth, 79 ppm tungsten and 8.5 ppm gold (Kimball and others, 1978, p. C257-C263). Scheelite and molybdenite also occur locally and scheelite is relatively abundant in panned concentrates. The sources of the anomalies are not fully known, but they probably include both the granitic rocks and the contact skarn zones.
  • Age = Tertiary.

Economic information

Economic information about the deposit and operations

Development status Occurrence
Commodity type Metallic

Comments on exploration

  • Status = Inactive

Mining district

District name Juneau

Comments on the workings information

  • Workings / Exploration = There are no known workings. MacKevett and others (1971) reported anomalous concentrations of tungsten in stream sediments in 1966. I followed up these anomalies in 1972 for Union Carbide. We confirmed the results and found abundant scheelite in panned concentrates, but did not proceed because the location was then in the National Monument; the future of development was uncertain. More samples were collected by the Bureau of Mines (Kimball and others, 1978, p. C257-C263). Apparently the Bureau concentrated more on the skarn and Cretaceous rocks than on the Tertiary intrusive.

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A013183
USGS Alaska Resource Data File ARDF MF071

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.

  • Deposit

    Cobb, E.H., 1981, Summaries of data on and lists of references to metallic and selected nonmetallic mineral occurrences in the Mt. Fairweather quadrangle, Alaska; Supplement to Open-file Report 78-316; Part A, Summaries of data to January 1, 1980: U.S. Geological Survey Open-File Report 81-249-A, 20 p.

  • Deposit

    Cobb, E. H., 1981, Summaries of data and lists of references to metallic and selected non-metallic mineral occurrences in the Mt. Fairweather quadrangle, Alaska, Supplement to Open-file Report 78-316: U. S. Geological Survey Open-File Report 81-249B, 15 p.

Comments on the references

  • Primary Reference = Kimball and others, 1978

General comments

Subject category Comment text
Deposit Model Name = Skarn and molybdenum-tungsten-tin porphyry similar to Sn skarn and porphyry Mo of Cox and Singer (1986; model 14b and 21b).
Deposit Model Number = 14b, 21b
Deposit Other Comments = the site is in Glacier Bay Park and Preserve.

Reporter information

Type Date Name Affiliation Comment
Reporter 14-APR-99 Hawley, C.C. Hawley Resource Group