Unnamed (near Devilfish Bay)

Prospect, Probably inactive

Commodities and mineralogy

Main commodities Cu; Mo; U
Ore minerals chalcopyrite; magnetite; and molybdenite
Gangue minerals calcsilicate minerals in tactite

Geographic location

Quadrangle map, 1:250,000-scale PE
Quadrangle map, 1:63,360-scale A-5
Latitude 56.085
Longitude -133.389
Nearby scientific data Find additional scientific data near this location
Location and accuracy Prospect near the head of Devilfish Bay, northwest Kosciusko, in the NW1/4, section 8, T. 67 S., R. 78 E.

Geologic setting

Geologic description

Magnetite, chalcopyrite, and minor molybdenite occur in tactite at contact between a Cretaceous quartz monzonite pluton and Cretaceous hornfels formed from calcareous graywacke of the Silurian Bay of Pillars Formation (Herreid and Kaufman, 1964, p. 4; Eakins, 1975, p. 54-57; and Brew and others, 1984). One sample of the tactite contained 8 ppm equivalent uranium.
Geologic map unit (-133.390723893278, 56.0846359295645)
Mineral deposit model Cu-Mo skarn with uranium (Cox and Singer, 1986; model 18b).
Mineral deposit model number 18b
Age of mineralization Related to intrusion of Cretaceous quartz monzonite pluton.
Alteration of deposit Calcsilicate minerals associated with intrusion of quartz monzonite into calcareous rocks.

Production and reserves

Workings or exploration Only work noted in 1975 was a single, hand-dug pit; little indication of any work since. But see PE053 for several blocks of claims staked around this prospect and active through at least 1981.
Indication of production None
Reserve estimates None
Production notes None


MRDS Number A010344


Reporters H.C. Berg (Fullerton, California) and D.J. Grybeck (USGS)
Last report date 11/1/1998