Mexico and Belvedere

Prospect, Inactive

Commodities and mineralogy

Main commodities Au
Other commodities Ag
Ore minerals pyrite

Geographic location

Quadrangle map, 1:250,000-scale JU
Quadrangle map, 1:63,360-scale B-2
Latitude 58.2598
Longitude -134.369
Nearby scientific data Find additional scientific data near this location
Location and accuracy This prospect is at an elevation of approximately 400 feet on Douglas Island, 1/4 mile southwest of the shore of Gastineau Channel and 0.4 mile south-southwest of the abandoned townsite of Treadwell. It is near the center of the east side the NE1/4 section 1, T. 42 S., R. 67 E. of the Copper River Meridian. The location is accurate.

Geologic setting

Geologic description

The Mexico and Belvedere prospect was discovered before 1886 and was developed by a 301-foot adit and a caved shaft. The rocks at the prospect consist of black phyllite intruded by a hornblende diorite sill that is 140 feet thick (Redman and others, 1989). The margins of the sill are hydrothermally altered and pyrite cubes are disseminated in these altered margins. The core of the sill is unaltered. U.S. Bureau of Mines samples contained up to 0.07 ppm gold and 0.3 ppm silver (Redman and others, 1989).
The rocks in the general area are Upper Jurassic or Cretaceous marine argillite and graywacke, interbedded with andesite or basalt (Brew and Ford, 1985). The bedded rocks are regionally metamorphosed to prehnite-pumpellyite or greenschist grade, and cut by diorite or gabbro dikes and sills.
Geologic map unit (-134.370767220003, 58.2594711389927)
Alteration of deposit The margins of the hornblende diorite sill are hydrothermally altered and pyritized.

Production and reserves

Workings or exploration The Mexico and Belvedere prospect was discovered before 1886 and was developed by a 301-foot adit and a caved shaft.
Indication of production None

References