Shower Gulch; Copper King; Keystone Prospect, Chistochina Mining District, Valdez-Cordova Census Area, Alaska, USAi

Regional Level Types
Shower Gulch; Copper King; Keystone Prospect	Prospect
Chistochina Mining District	Mining District
Valdez-Cordova Census Area	Census Area
Alaska	State
USA	Country

The locality is in the Wrangell-Saint Elias National Park and Preserve.
Location: This prospect is on Shower Gulch at the head of the Kotsina River. It is at an elevation of about 3,800 feet, 2,500 feet north-northeast of elevation 5522 and 2,500 feet east-northeast of the center of section 2, T. 2 S., R. 9 E. of the Copper River Meridian. This is locality 164 of MacKevett (1978) and locality 7 of MacKevett and others (1978). The location is accurate to within about 100 feet. Cobb and MacKevett (1980) included this prospect under the name 'Shower Gulch'.
Geology: The deposit at this prospect consists of native copper in the amygdaloidal upper parts of basalt flows in the Triassic Nikolai Greenstone (Moffit and Mertie, 1923; MacKevett, 1976). The flows are 5 to 25 feet thick The amygdules are mostly filled with quartz and epidote but leaves, grains, and masses of native copper are also present in them (Moffit and Mertie, 1923). A small amount of chalcopyrite was identified in greenstone replaced by quartz and epidote. The deposits were explored by open cuts. The widespread deposition of copper in Triassic greenstone and limestone of the area is thought to have accompanied regional deformation and low-grade metamorphism in the Late Jurassic or Early Cretaceous (MacKevett and others, 1997). Copper-bearing minerals were deposited in the underlying Nikolai Greenstone at about 112 Ma (Silberman and others, 1980).
Workings: The prospect was explored by open cuts.
Age: Cretaceous? The widespread deposition of copper in Triassic greenstone and limestone of the area is thought to have accompanied regional deformation and low-grade metamorphism in the Late Jurassic or Early Cretaceous (MacKevett and others, 1997). Copper-bearing minerals were deposited in the underlying Nikolai Greenstone at about 112 Ma (Silberman and others, 1980).
Alteration: Oxidation.

Commodities (Major) - Cu
Development Status: None
Deposit Model: Basaltic Cu (Cox and Singer, 1986; model 23)

Other Databases

Link to USGS - Alaska:	MC023

Other Regions, Features and Areas containing this locality

References