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  3. Alaska Resource Data File (ARDF)

Unnamed (near Styx River)

Occurrence, Inactive

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Commodities and mineralogy

Main commodities Ag; Cu; Sn
Ore minerals azurite; bornite; chalcopyrite; malachite
Gangue minerals albite; iron oxide; quartz; sericite; tourmaline

Geographic location

Quadrangle map, 1:250,000-scale LH
Quadrangle map, 1:63,360-scale C-1
Latitude 61.6839
Longitude -153.0541
Nearby scientific data Find additional scientific data near this location
Location and accuracy 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.

Geologic setting

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).
Geologic map unit (-153.056308828737, 61.6832891029723)
Mineral deposit model Polymetallic veins? (Cox and Singer, 1986, model 22c)
Mineral deposit model number 22c?
Age of mineralization Tertiary. Shear zone and mineralization crosscuts Tertiary intrusive rocks.
Alteration of deposit Granodiorite in the shear zone is altered to quartz, sericite, albite, and iron oxide minerals.

Production and reserves

Workings or exploration Reconnaissance observation and sampling has been completed in this area (Reed and Elliott, 1970).
Indication of production None

References

MRDS Number A013069

References

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.
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.
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.
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.
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 70-271, 24 p., 4 sheets, scale 1:250,000.
Reporters Travis L. Hudson and Madelyn A. Millholland
Last report date 6/10/2001