Unnamed Occurrence (ARDF - MH362; on upper Alteration Creek), Chistochina Mining District, Valdez-Cordova Census Area, Alaska, USAi

Regional Level Types
Unnamed Occurrence (ARDF - MH362; on upper Alteration Creek)	- not defined -
Chistochina Mining District	Mining District
Valdez-Cordova Census Area	Census Area
Alaska	State
USA	Country

Location: Alteration Creek is a south-southeast-flowing tributary of the Slana River, which it enters about 5 miles south of Gillett Pass. The occurrence is on the west side of Alteration Creek at an elevation of about 3,800 feet. It is near the center SW1/4 section 3, T. 14 N., R. 6 E., Copper River Meridian. The occurrence corresponds to locality 2 of Richter and others (1977) and locality 144 in table 2 of Nokleberg and others (1991) and is near locality 32 on figure 6 of Cobb (1979, [OFR 79-238)].
Geology: The rocks in the vicinity of this occurrence consist of intensely hydrothermally altered Tetelna Volcanics of Pennsylvanian age (Richter and others, 1977). (Richter [1967] originally mapped the country rocks as Slana basalt.) The Tetelna Volcanics are mainly composed of flows, avalanche deposits, and tuff interbedded with lesser amounts of fine-grained volcaniclastic rock. A granitic pluton of Cretaceous (?) age crops out about a mile east of the altered zone and could underlie it. The occurrence consists of azurite- and malachite-stained quartz veins that cut intensely iron stained silicified volcanic rocks. The veins contain small amounts of chalcopyrite and pyrite. A sample collected from a chalcopyrite-bearing vein assayed 1.5 percent copper, 0.02 ounce of gold per ton, and 0.54 ounce of silver per ton (Richter, 1967).
Workings: Only limited surface sampling.
Age: Possibly Pennsylvanian to Permian, on the basis of the age of the host rocks; may be related to a nearby Cretaceous (?) intrusion.
Alteration: Silicification and pyritization of Tetelna Volcanics. Oxidation of iron sulfides has been so extensive that primary rock textures are largely obliterated (Richter, 1967).

Commodities (Major) - Ag, Au, Cu
Development Status: None
Deposit Model: Porphyry Cu, distal (Cox and Singer, 1986; model 20c).

Other Databases

Link to USGS - Alaska:	MH362

Other Regions, Features and Areas containing this locality

References