Prospect, Undetermined

Commodities and mineralogy

Main commodities U
Other commodities Amethyst
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale RM
Quadrangle map, 1:63,360-scale C-1
Latitude 61.632
Longitude -159.229
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Ptarmigan prospect is on the southwest flank of the Russian Mountains. It is on the low ridge along the west side of Mission Creek, opposite the mouth of Ptarmigan Gulch. The map site is at an elevation of about 1,050 feet and about 0.25 mile south-southeast of the center of sec. 22, T. 18 N., R. 55 W., of the Seward Meridian. This is sample locality 19 of Bundtzen and Laird (1991).

Geologic setting

Geologic description

Bundtzen and Laird (1991) report that a brecciated and quartz-flooded zone in hornfels contains small vugs lined with euhedral, even doubly terminated, amethyst crystals to 5 centimeters long. A sample of this material contained 38 ppm uranium. The hornfels is developed in Cretaceous clastic sedimentary rocks peripheral to the intrusive complex of the Russian Mountains (Bundtzen and Laird, 1991).
Geologic map unit (-159.231359833112, 61.6312844145581)
Mineral deposit model Silicified zone in hornfels
Age of mineralization Late Cretaceous or Tertiary. Veins postdate hornfels developed around the intrusive complex of the Russian Mountains. Quartz monzonite from this complex has yielded a K/Ar age of 70.3 +/- 2.1 Ma (Bundtzen and Laird, 1991).
Alteration of deposit Silicification.

Production and reserves

Workings or exploration Some small surface pits may be present.
Indication of production None