Unnamed (near Tsirku Glacier )

Occurrence in Alaska, United States with commodities Silver, Gold, Copper, Lead, Zinc, Barium-Barite, Cobalt

Geologic information

Identification information

Deposit ID 10002199
MRDS ID A013099
Record type Site
Current site name Unnamed (near Tsirku Glacier )

Geographic coordinates

Geographic coordinates: -136.45213, 59.31974 (WGS84)
Relative position This occurrence is located in the headwaters of the Tsirku River, 0.7 miles east of the Alaska-Canada border and 0.6 miles north of the Tsirku Glacier at an elevation of 2,500 feet. It is in the NW1/4, section 35, T. 29 S., R. 53 E. of the Copper River Meridian. It is shown as number 156 of Still and others (1984) which is at the approximate center of an area of anomalously high samples that includes map numbers 149 to 168.
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Silver Primary
Gold Primary
Copper Primary
Lead Primary
Zinc Primary
Barium-Barite Secondary
Cobalt Secondary

Materials information

Materials Type of material
Chalcopyrite Ore
Galena Ore
Pyrite Ore
Pyrrhotite Ore
Sphalerite Ore
Calcite Gangue
Quartz Gangue

Alteration

  • (Local) Altered volcanics are mentioned but not described (Still and others, 1984).

Mineral occurrence model information

Model code 85
USGS model code 22c
Deposit model name Polymetallic veins
Mark3 model number 46
Model code 91
USGS model code 24b
Deposit model name Massive sulfide, Besshi (Japanese deposits)
Mark3 model number 30
Model code 184
USGS model code 28a
Deposit model name Massive sulfide, kuroko
Mark3 model number 93

Host and associated rocks

  • Host or associated Associated
    Rock type Volcanic Rock (Aphanitic) > Intermediate Volcanic Rock > Andesite
    Stratigraphic age (youngest) Late Permian
  • Host or associated Host
    Rock type Metamorphic Rock > Metasedimentary Rock > Slate
    Rock unit name Porcupine Slate;Porcupine Slate
    Rock description Porcupine Slate;Porcupine Slate

Nearby scientific data

(1) -136.45213, 59.31974

Comments on the geologic information

  • Geologic Description = According to Still and others (1984): 'Float and bedrock samples contain up to 6.2% zinc, 2.33% copper, 1.18% lead, 450 ppm cobalt, 49.84 ppm silver, 0.30 ppm gold, 1.13% barium, 200 ppm tin, 400 ppm arsenic, 300 ppm nickel, and 900 ppm bismuth. The samples include: 'pyrrhotite bearing quartz vein in slate', 'quartz boulder with 0.1 foot pyrrhotite band', 'massive pyrrhotite boulder with sparse quartz', 'altered volcanic boulder with massive sphalerite, chalcopyrite and galena(?)', and '70% silica, 30% sulfides - pyrrhotite, chalcopyrite and sphalerite.' Bedrock in the area is Paleozoic slate, metavolcanics, and limestone near a Cretaceous diorite, quartz diorite and granodiorite pluton (MacKevett and others, 1974).? the nature of this occurrence is unclear. It is probably either a polymetallic quartz-sulfide vein(s) or a volcanogenic, massive sulfide. If it is a vein(s), then it is probably Cretaceous based on the age of nearby intrusives (MacKevett and others, 1974). If it is a volcanogenic massive sulfide occurrence, then it is probably Late Triassic like the Windy Craggy and Greens Creek massive sulfide deposits (Still, 1984 [OF 118-84]; Newberry and others, 1997).
  • Age = If it is a quartz-sulfide vein, it is probably Cretaceous, based on the age of nearby intrusives (MacKevett and others, 1974). If it is a volcanogenic massive sulfide, it is probably Late Triassic like the Windy Craggy and Greens Creek massive-sulfide deposits nearby (Still, 1984 (OFR 118-84); Newberry and others, 1997)

Economic information

Economic information about the deposit and operations

Development status Occurrence
Commodity type Metallic

Comments on exploration

  • Status = Probably inactive

Mining district

District name Juneau (Skagway subdistrict)

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A013099
USGS Alaska Resource Data File ARDF SK056

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

    Berg, H.C., 1984, Regional geologic summary, metallogenesis, and mineral resources of southeastern Alaska: U.S. Geological Survey Open-file Report 84-572, 298 p., 1 plate, scale approx. 1:600,000.

  • Deposit

    Still, J.C., 1984, Stratiform massive sulfide deposits in the Mt. Henry Clay area, southeast Alaska: U.S. Bureau of Mines Open-File Report 118-84, 65 p.

  • Deposit

    Still, J.C., Weir, K.R., Gilbert, W.G., and Redman, E.C., 1984, Stream-sediment, float, and bedrock sampling in the Porcupine mining area, southeast Alaska: U.S. Bureau of Mines Open-File Report 173-84, 19 p.

  • Deposit

    Newberry, R.J., Crafford, T.C., Newkirk, S.R., Young, L.E., Nelson, S.W., and Duke, N.A., 1997, Volcanogenic massive sulfide deposits of Alaska, in Goldfarb, R.J. and Miller, L. D., eds., Mineral deposits of Alaska: Economic Geology Monograph 9, p. 120-150.

Comments on the references

  • Primary Reference = Still and others, 1984 (OF 118-84)

General comments

Subject category Comment text
Deposit Model Name = Unknown, but probably either a polymetallic quartz-sulfide vein or a Besshi- or Kuroko-type volcanogenic massive-sulfide occurrence (Cox and Singer, 1986; models 22c, 24b, 28a).
Deposit Model Number = 22c?, 24b?, 28a?

Reporter information

Type Date Name Affiliation Comment
Reporter 04-FEB-2001 T.C. Crafford T. Crafford & Associates