Unnamed Occurrence (ARDF - MC153; west of upper Toby Creek), Nizina Mining District, Valdez-Cordova Census Area, Alaska, USAi

Regional Level Types
Unnamed Occurrence (ARDF - MC153; west of upper Toby Creek)	- not defined -
Nizina Mining District	Mining District
Valdez-Cordova Census Area	Census Area
Alaska	State
USA	Country

The locality is in the Wrangell-Saint Elias National Park and Preserve.
Location: This occurrence is on the ridge south of Toby Creek. it is at an elevation of about 6,400 feet, 2,500 feet northwest of elevation 7140 and 1,500 feet north of the center of section 12, T. 5 S., R. 17 E. of the Copper River Meridian. This is locality 70 of MacKevett (1976); the location is accurate to within a few hundred feet.
Geology: This occurrence consists of a 2- to 3-foot-wide, malachite- and azurite-bearing vein in a fault zone that cuts Triassic Nikolai Greenstone (MacKevett and Smith, 1972; MacKevett, 1976). A sample of the vein contained 2 parts per million (ppm) silver, 500 ppm arsenic, and 20,000 ppm copper (MacKevett and Smith, 1968, sample 111). Copper mineralization is common in Nikolai Greenstone and is thought to have accompanied regional deformation and low-grade metamorphism in the Late Jurassic to Early Cretaceous (MacKevett and others, 1997).
Workings: Only limited surface sampling.
Age: Cretaceous? Copper mineralization is common in Nikolai Greenstone and is thought to have accompanied regional deformation and low-grade metamorphism in the Late Jurassic to Early Cretaceous (MacKevett and others, 1997).
Alteration: Oxidation.

Commodities (Major) - Cu; (Minor) - Ag, As
Development Status: None
Deposit Model: Basaltic Cu (Cox and Singer, 1986; model 23)

Other Databases

Link to USGS - Alaska:	MC153

Other Regions, Features and Areas containing this locality

References