Prospect, Probably inactive

Commodities and mineralogy

Main commodities Au
Ore minerals gold
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale SD
Quadrangle map, 1:63,360-scale C-5
Latitude 57.5919
Longitude -133.33729
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Gertrude prospect is about 0.3 mile south of the mouth of Spruce Creek at the head of Windham Bay. It is at or near the adit symbol shown on the USGS 1:63,360-scale topographic map about 0.5 mile southeast of the northwest corner of section 26, T. 49 S., R. 75 E. There is another adit on the Gertrude prospect nearby at an elevation of about 400 feet. Figures 29 and 30 of Kimble and others (1984) are maps of the two adits.

Geologic setting

Geologic description

The Gertrude prospect consists of two adits; one is just above sea level and the other is nearby at an elevation of about 400 feet (Kimble and others, 1984). The adits were driven about 1920 and there has been little work on the property since. The lower adit is 160 feet long. A quartz pod and irregular vein less than 10 feet long is exposed. A 6.0-foot channel sample contained 0.30 part per million gold. The upper adit is at an elevation of about 400 feet; it exposes a short quartz pod that strikes N50W and dips 35NE. A random sample of the pod contained 0.40 ppm gold. The host rock in both adits is phyllitic schist, part of the Cretaceous hornblende schist unit of Brew and Grybeck (1984).
Geologic map unit (-133.338997549856, 57.5915593297913)
Mineral deposit model Low-sulfide gold-quartz vein (Cox and Singer, 1986; model 39a).
Mineral deposit model number 39a
Age of mineralization Quartz veins cut Cretaceous schist.

Production and reserves

Workings or exploration The prospect has two adits driven about 1920; one is 160 feet long and the other is 55 feet long. There has been little work on the property since the 1920s.
Indication of production None

Additional comments

The prospect is in the Chuck River Wilderness Area which is closed to mineral exploration and mining.


MRDS Number A013341


Reporters Donald Grybeck (U.S. Geological Survey)
Last report date 10/8/2004