Unnamed Occurrence (ARDF - NB042; west of lower Nabesna Glacier), Chisana Mining District, Valdez-Cordova Census Area, Alaska, USAi

Regional Level Types
Unnamed Occurrence (ARDF - NB042; west of lower Nabesna Glacier)	- not defined -
Chisana Mining District	Mining District
Valdez-Cordova Census Area	Census Area
Alaska	State
USA	Country

The occurrence is in the Wrangell-St. Elias National Preserve.
Location: This occurrence is on the east nose of a low ridge along the north side of a west tributary stream to lower Nabesna Glacier. It is at an elevation of about 3,800 feet, 2,500 feet west of the glacier and about 1.6 miles east-southeast of elevation 5370. The site is in the NE1/4 of section 13, T. 4 N., R. 13 E. of the Copper River Meridian. This is locality 11 of Richter (1973), locality 21 of Richter and others (1975), and National Park Service locality WRST-29 (unpublished data). Cobb and Richter (1980) included this locality as an 'Unnamed occurrence'. It is located to within a few hundred feet.
Geology: Small irregular masses of pyrite and minor chalcopyrite occur in contact-metamorphosed Triassic, Nikolai Greenstone. A chip sample of pyrite-bearing greenstone contained 500 parts per million (ppm) copper, more than 100 ppm scandium, 200 ppm nickel, and 300 ppm chromium (Richter and Matson, 1970 [OFR 70-276]). This occurrence is in the contact zone of a diorite stock that is inferred to be a border phase of the mid-Cretaceous Nabesna pluton (Richter, 1973).
Age: Mid-Cretaceous? The nearby diorite stock is inferred to be a border phase of the mid-Cretaceous Nabesna pluton (Richter, 1973).
Alteration: Tactite development in contact metamorphosed greenstone.

Commodities (Major) - Cu
Development Status: None
Deposit Model: Contact metamorphic copper deposit

Other Databases

Link to USGS - Alaska:	NB042

Other Regions, Features and Areas containing this locality

References