Unnamed (west of upper Toby Creek)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Cu
Other commodities Ag; As
Ore minerals azurite; malachite

Geographic location

Quadrangle map, 1:250,000-scale MC
Quadrangle map, 1:63,360-scale B-4
Latitude 61.4537
Longitude -142.2808
Nearby scientific data Find additional scientific data near this location
Location and accuracy 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.

Geologic setting

Geologic description

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).
Geologic map unit (-142.282859112692, 61.4532841586484)
Mineral deposit model Basaltic Cu (Cox and Singer, 1986; model 23)
Mineral deposit model number 23
Age of mineralization 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 of deposit Oxidation.

Production and reserves

Workings or exploration Only limited surface sampling.
Indication of production None

Additional comments

The locality is in the Wrangell-Saint Elias National Park and Preserve.

References

MRDS Number A011707

References

Reporters Travis L. Hudson (Applied Geology, Inc.)
Last report date 1/12/2003