Tsirku Silver

Occurrence in Alaska, United States with commodities Silver, Copper, Lead, Zinc, Gold

Geologic information

Identification information

Deposit ID 10308246
Record type Site
Current site name Tsirku Silver

Geographic coordinates

Geographic coordinates: -136.05212, 59.31974 (WGS84)
Relative position This occurrence is centered at an elevation of 3,800 feet about 1.1 mile east of the Tsirku River and 4.0 miles, N59W from the summit of Chunekukleik Mountain. It is in the approximate center of a northwest- trending elongate area with several occurrences of ore minerals that is about 1/2 mile long and 1/4 mile wide. This area is shown as number 25 on sheet of Still and others (1991).
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Silver Primary
Copper Primary
Lead Primary
Zinc Primary
Gold Secondary

Materials information

Materials Type of material
Galena Ore
Malachite Ore
Pyrite Ore
Sphalerite Ore
Quartz Gangue

Mineral occurrence model information

Model code 85
USGS model code 22c
Deposit model name Polymetallic veins
Mark3 model number 46

Host and associated rocks

  • Host or associated Host
    Chronological age 29.3
    Uncertainty 1
    Stratigraphic age (youngest) Paleogene
    Chronological age 33
    Uncertainty 1
    Stratigraphic age (youngest) Paleogene

Nearby scientific data

(1) -136.05212, 59.31974

Comments on the geologic information

  • Geologic Description = Still and others (1991) informally named this occurrence 'Tsirku Silver'. They describe it as, '...scattered, narrow, discontinuous silver-bearing zinc-galena-quartz veins hosted in dolomite and limy slate.' A representative chip sample of the highest grade vein contained 0.48 ppm gold, 653.5 ppm silver, 18.4 % zinc, and 6.2 % copper. According to Gilbert and others (1987), the veins occur within a 6-square-mile area immediately east of the Tsirku River that is cut by a swarm of felsic, intermediate, and mafic dikes. The dikes are probably Tertiary in age, based on a 29.3 + 1 to 33.0 + 1 m.y. age of nearby quartz diorite and granodiorite bodies (MacKevett and others, 1974). The probable Devonian or Mississippian age of the host rocks (Gilbert and others, 1987) establishes a maximum age for the veins. More likely, the veins are the same inferred Tertiary age as the dikes.
  • Age = the veins must be younger than the Devonian to Mississippian age of the host rocks (Gilbert and others, 1987) and are probably about the same age as the dikes in the area, which are inferred to be 29.3 + 1 to 33.0 + 1 m.y. based on the age of nearby quartz diorite and granodiorite (MacKevett and others, 1974).
  • Age = Chronological age is for the nearby quartz diorite and granodiorite. Host rock is Mississippian - Devonian.

Economic information

Economic information about the deposit and operations

Development status Occurrence

Comments on exploration

  • Status = Probably inactive

Mining district

District name Juneau (Skagway subdistrict)

Comments on the workings information

  • Workings / Exploration = This occurrence was discovered in 1986 during the Bureau of Mines study reported in Still and others (1991).

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Alaska Resource Data File ARDF SK034

Bibliographic references

  • Deposit

    MacKevett, E.M., Jr., Robertson, E.C., and Winkler, G.R., 1974, Geology of the Skagway B-3 and B-4 quadrangles, southern Alaska: U.S. Geological Survey Professional Paper 832, 33 p.

  • Deposit

    Gilbert, W.G., Burns, L.E., Redman, E.C., and Forbes, R.B., 1987, Preliminary bedrock geology and geochemistry of the Skagway B-3 Quadrangle, Alaska: Alaska Division of Geological and Geophysical Surveys Report of Investigations 87-2, 2 sheets, scale 1:36,200.

  • Deposit

    Gilbert, W.G., and Redman, E.C., 1989, Lode deposits, prospects, and occurrences of the Porcupine mining area, southeast Alaska: U.S. Bureau of Mines Open-File Report 17-89, 1 sheet, scale 1:39,600.

  • Deposit

    Gilbert, W.G., Still, J.C., Burns, L.E., Wier, K.R., and Redman, E.C., 1991, Geochemistry of Haines-Klukwan-Porcupine area, southeastern Alaska: Alaska Division of Geological and Geophysical Surveys Report of Investigations 91-5, 1 sheet, scale 1:63,360, 75 p.

  • Deposit

    Still, J.C., 1991, Bureau of Mines mineral investigations in the Juneau mining district, Alaska, 1984 - 1988, v. 2, Detailed mine, prospect, and mineral occurrence descriptions, section A, Haines-Klukwan-Porcupine subarea: U.S. Bureau of Mines of Mines Special Publication, 214 p.

  • Deposit

    Still, J.C., Hoekzema, R.B., Bundtzen, T.K., Gilbert, W.G., Wier, K.R., Burns, L.E., and Fechner, S.A., 1991, Economic geology of Haines-Klukwan-Porcupine area, southeastern Alaska: Alaska Division of Geological and Geophysical Surveys Report of Investigations 91-4, 156 p., 5 sheets, scale 1:63,360.

Comments on the references

  • Primary Reference = Still and others, 1991

General comments

Subject category Comment text
Deposit Model Name = Polymetallic quartz-sulfide veins (Cox and Singer, 1986; model 22c).

Reporter information

Type Date Name Affiliation Comment
Reporter 04-FEB-01 T.C. Crafford T. Crafford & Associates