Unnamed (near Styx River)

Occurrence in Alaska, United States with commodities Silver, Copper, Tin

Geologic information

Identification information

Deposit ID 10002172
MRDS ID A013069
Record type Site
Current site name Unnamed (near Styx River)

Geographic coordinates

Geographic coordinates: -153.05693, 61.68337 (WGS84)
Relative position This occurrence is on the nose of a ridge above an east tributary to the Styx River. It is at an elevation of about 4,500 feet, 0.6 mile northwest of peak 6050. The map site is in the NE1/4 section 3, T 18 N, R 21 W, of the Seward Meridian. This is locality 12 of Cobb (1972 [MF 412]; 1976 [OF 76-485]). The location is probably accurate to within a quarter of a mile.
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Silver Primary
Copper Primary
Tin Primary

Comments on the commodity information

  • Gangue = iron oxide

Materials information

Materials Type of material
Azurite Ore
Bornite Ore
Chalcopyrite Ore
Malachite Ore
Albite Gangue
Quartz Gangue
Sericite Gangue
Tourmaline Gangue

Alteration

  • (Local) Granodiorite in the shear zone is altered to quartz, sericite, albite, and iron oxide minerals.

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 Associated
    Rock type Plutonic Rock > Ultramafic Intrusive Rock > Hornblendite
    Rock unit name Mount Estelle Pluton
    Rock description Mount Estelle Pluton
    Stratigraphic age (youngest) Pliocene
    Stratigraphic age (youngest) Pliocene
    Stratigraphic age (youngest) Pliocene
  • Host or associated Host
    Rock type Plutonic Rock > Ultramafic Intrusive Rock > Hornblendite

Nearby scientific data

(1) -153.05693, 61.68337

Comments on the geologic information

  • Geologic Description = Reed and Elliott (1970) reported that a northwest-trending shear zone in altered granodiorite contains as much as 10 percent pyrite and chalcopyrite. The shear zone is about 5 feet wide, exposed over a length of 30 feet, and locally stained with iron oxide, malachite, and azurite. Alteration minerals in the shear zone include quartz, sericite, albite, and iron oxides. Disseminated chalcopyrite is present in granodiorite within 10 feet of the shear zone. Float downslope of a nearby iron oxide-stained zone contains chalcopyrite, bornite, other sulfides, and tourmaline. In addition to anomalous copper values, rock samples contain as much as 700 ppm tin, and 15 ppm silver. Nearby float samples contain as much as 300 ppm silver and greater than 1,000 ppm tin. Quartz-feldspar porphyry dikes trend northwest parallel to the mineralized shear zone. The host intrusive rocks are Tertiary plutons of the Alaska-Aleutian Range batholith (Cobb and Reed, 1981).
  • Age = Tertiary. Shear zone and mineralization crosscuts Tertiary intrusive rocks.

Economic information

Economic information about the deposit and operations

Development status Occurrence
Commodity type Metallic

Comments on exploration

  • Status = Inactive

Mining district

District name McGrath

Comments on the workings information

  • Workings / Exploration = Reconnaissance observation and sampling has been completed in this area (Reed and Elliott, 1970).

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A013069
USGS Alaska Resource Data File ARDF LH014

Bibliographic references

  • Deposit

    Gamble, B.M., Bailey, E. A., and Reed, B. L., 1989, Gold occurrences near Snowcap Mountain, Lime Hills B-2 quadrangle, Alaska: U.S. Geological Survey Open-File Report 89-0646, 8 p.

  • Deposit

    Cobb, E.H., 1976, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Iliamna, Lake Clark, Lime Hills, and McGrath quadrangles, Alaska: U.S. Geological Survey Open-File Report 76-485, 101 p.

  • Deposit

    Cobb, E.H., 1972, Metallic mineral resources map of the Lime Hills quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-412, 1 sheet, scale 1:250,000.

  • Deposit

    Cobb, E.H., and Reed, B.L., 1981, Summaries of data on and lists of references to metallic and selected nonmetallic mineral occurrences in the Iliamna, Lake Clark, Lime Hills, and McGrath quadrangles, Alaska; Supplement to Open-File Report 76-485; Part A, Summaries to January 1, 1981: U.S. Geological Survey Open-File Report 81-1343-A, 25 p.

  • Deposit

    Reed, B.L., and Elliott, R.L., 1970, Reconnaissance geologic map, analyses of bedrock and stream sediment samples, and an aeromagnetic map of parts of the southern Alaska Range: U.S. Geological Survey Open-File Report 70-217, 145 p., 1 sheet, scale 1:250,000. (Also published as U.S. Geological Survey Open-File Report 413).

Comments on the references

  • Primary Reference = Reed and Elliott, 1970

General comments

Subject category Comment text
Deposit Model Name = Polymetallic veins? (Cox and Singer, 1986, model 22c)

Reporter information

Type Date Name Affiliation Comment
Reporter 10-JUN-2001 Travis L. Hudson Applied Geology
Reporter 10-JUN-2001 Travis L. Hudson Applied Geology