Prospect, Probably inactive

Commodities and mineralogy

Main commodities Jade
Ore minerals nephrite
Gangue minerals chlorite; serpentine

Geographic location

Quadrangle map, 1:250,000-scale NB
Quadrangle map, 1:63,360-scale D-6
Latitude 62.9312
Longitude -143.6386
Nearby scientific data Find additional scientific data near this location
Location and accuracy This prospect is 1,000 feet north of the Mentasta Lake road and 2,100 feet northwest of the intersection of this road with the Glen Highway. It is at an elevation of about 2,700 feet in the SE1/4 of section 2, T. 13 N., R. 9 E. of the Copper River Meridian. It is locality 7 of Richter (1967) and locality 2 of Richter and others (1975). It is located to within a few hundred feet.

Geologic setting

Geologic description

A thin band of serpentinite in Devonian metasedimentary rocks was prospected for asbestos in the 1950s by L.L. Patten (Richter, 1967). A dense, slightly schistose, and hard rock from one of the prospect pits was found to contain nephrite (jade). The nephrite is associated with rodingite inclusions and ranges in color from dark to light green with some apple-green zones. The deposit has produced a number of pounds of semiprecious stone (Richter and others, 1975). The alpine-type ultramafic body that hosts the deposit is Cretaceous (Richter, 1976).
Geologic map unit (-143.640803392766, 62.930826060892)
Mineral deposit model Serpentine-hosted asbestos (Cox and Singer, 1986; model 8d)
Mineral deposit model number 8d
Age of mineralization The serpentinite body that hosts the deposit is inferred to be Cretaceous (Richter, 1976).
Alteration of deposit Serpentinization.

Production and reserves

Workings or exploration Several small prospecting pits have been dug on this deposit.
Indication of production Undetermined
Production notes The deposit produced a number of pounds of jadeite over 10 years before 1975 (Richter and others, 1975).