Unnamed Occurrence (ARDF - CV057; north wall Grinnell Glacier), Copper River Mining District, Valdez-Cordova Census Area, Alaska, USAi

Regional Level Types
Unnamed Occurrence (ARDF - CV057; north wall Grinnell Glacier)	- not defined -
Copper River Mining District	Mining District
Valdez-Cordova Census Area	Census Area
Alaska	State
USA	Country

Chugach Alaska Corporation, Anchorage, Alaska has control of these lands.
Location: This occurrence is at an elevation of about 2200 feet on the north wall of Grinnell Glacier. It is in SE1/4 sec. 24, T. 13 S., R. 3 E., of the Copper River Meridian. Site is accurately located to within 1000 ft. This location is site C-11 of Jansons and others (1984).
Geology: This occurrence consists of sulfide-bearing shear zones 2 to 10 feet wide in slate and greenstone of the Upper Cretaceous Valdez Group (Nelson and others, 1985). Ore minerals include arsenopyrite, chalcopyrite, malachite, pyrite, and pyrrhotite. Four chip samples collected and analyzed by the U.S. Bureau of Mines contained 255 ppm to 0.13% Cu; nine grab samples contained 13 ppm to 0.19% Cu (Jansons and others, 1984). This site is at the eastern end of a 65-mile-long belt of similar rocks that to the west host massive sulfide deposits (Nelson and others, 1984; 1985; Crowe and others, 1992). A massive-sulfide boulder found on the south side of Grinnel Glacier contained 30% pyrite, 3% chalcopyrite, 1% sphalerite in a quartz-sericite gangue (Kodosky and Teller, 1989). Assays of selected samples ranged from 1100 ppm to 1.8% Cu.
Workings: Site examined during U.S. Bureau of Mines and U.S.G.S. mineral resource assessment of the Chugach National Forest (Jansons and others, 1984; Nelson and others, 1984). Site also examined in 1988 by Kodosky and Teller (1989) for the Chugach Alaska Corporation. Their evaluation indicated some potential for copper mineralization. Four chip samples collected and analyzed by the U.S. Bureau of Mines contained 255 ppm to 0.13% Cu; nine grab samples contained 13 ppm to 0.19% Cu (Jansons and others, 1984). A massive-sulfide boulder found on the south side of Grinnel Glacier contained 30% pyrite, 3% chalcopyrite, 1% sphalerite in a quartz-sericite gangue. Assays of selected samples ranged from 1100 ppm to 1.8% Cu.
Age: Late Cretaceous based on the age of the host rocks.
Alteration: Local alteration of copper minerals.

Commodities (Major) - Cu; (Minor) - Zn
Development Status: None
Deposit Model: Besshi massive sulfide (Cox and Singer, 1986; model 24b)

Other Databases

Link to USGS - Alaska:	CV057

Other Regions, Features and Areas containing this locality

References