Unnamed Occurrence (ARDF - MH359; near Gillett Pass), Chistochina Mining District, Valdez-Cordova Census Area, Alaska, USAi

Regional Level Types
Unnamed Occurrence (ARDF - MH359; near Gillett Pass)	- not defined -
Chistochina Mining District	Mining District
Valdez-Cordova Census Area	Census Area
Alaska	State
USA	Country

Location: The occurrence is about 1.2 miles west of Gillett Pass at an elevation of about 4,200 feet. It is in the SW1/4SE1/4 section 16, T. 15 N., R. 6 E., Copper River Meridian. It corresponds to locality 6 of Richter (1967), locality 32 on figure 6 of Cobb (1979 [OFR 79-238]), locality 53 of MacKevett and Holloway (1977), and locality 144 in table 2 of Nokleberg and others (1991). The location is a general one in a dunite body that is exposed for a strike length of about 2 miles.
Geology: Low-grade chromite deposits occur in a lenticular body of dunite about 2 miles long and one-half mile wide; the dunite is a near-vertical body within the Denali Fault zone (Richter, 1967). The dunite is partly enclosed by amphibolite and pyroxenite that extend to the east beyond the dunite mass. Chromite occurs in gneissoid layers in the ultramafic rocks. On the basis of representative samples, the dunite contains about 1.2 percent chromic oxide and 0.4 percent nickel. The nickel possibly occurs in olivine and its alteration products. At places chromite is segregated into massive lenses. The largest lens found by Richter (1967) was about 1 foot long and 2 inches thick, but he noted that the body was poorly exposed and that larger bodies of chromite could exist. No samples were analyzed for platinum group metals.
Workings: There are no workings.
Age: Late Triassic (?).
Alteration: Serpentinization of dunite.

Commodities (Major) - Cr; (Minor) - Ni
Development Status: None
Deposit Model: Chromite disseminated in layered mafic-ultramafic complex (Cox and Singer, 198

Other Databases

Link to USGS - Alaska:	MH359

Other Regions, Features and Areas containing this locality

References