Unnamed (near Styx River)

Occurrence, Inactive

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