Unnamed (near hill 1630)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Cu; Zn
Other commodities Ag; Bi; Cd
Gangue minerals epidote; quartz; tourmaline

Geographic location

Quadrangle map, 1:250,000-scale ID
Quadrangle map, 1:63,360-scale B-2
Latitude 62.35349
Longitude -156.9333
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is near the top of hill 1630 on a ridge separating Granite Creek from the Little East Fork of George River. The occurrence is about 0.5 mile southwest of the center of section 8, T. 26 N., R. 41 W., of the Seward Meridian. The location is accurate.

Geologic setting

Geologic description

This occurrence consists of a system of quartz-tourmaline-epidote veins in hornfels at the southern contact of a small, biotite-quartz-monzonite stock. The stock has been dated as 71.1 Ma (Bundtzen, Miller, and Laird, 1986). Major oxide data for the intrusion are given in Miller and Bundtzen (1994). The mineralized veins occupy vertical joints that strike about N40E and N44W. The size of the occurrence is uncertain. Grab samples of mineralization contain up to 860 parts per million (ppm) zinc, 300 ppm copper, 2,000 parts per billion silver, 5.1 ppm cadmium, and 10 ppm bismuth (McGimsey and others, 1988).
Geologic map unit (-156.935692384895, 62.352809882581)
Mineral deposit model Polymetallic vein (Cox and Singer, 1986; model 22c).
Mineral deposit model number 22c
Age of mineralization Undated; the quartz monzonite stock that hosts the mineralization has been dated as 71.1 Ma (Bundtzen, Miller, and Laird, 1986).
Alteration of deposit Development of epidote-quartz-tourmaline greisen.

Production and reserves

Workings or exploration Samples were collected by the U.S. Geological Survey and Alaska Division of Geological and Geophysical Surveys in 1984 (McGimsey and others, 1988). Placer Dome Exploration flew an aeromagnetic survey over the Upper Granite Creek area including the prospect area in 1996. Results of that survey have not been released (L.E. Wyrick, oral communication, 2003).
Indication of production None