Gold

Prospect, Probably inactive

Commodities and mineralogy

Main commodities Ag; Au; Pb
Ore minerals galena
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale SD
Quadrangle map, 1:63,360-scale C-4
Latitude 57.5794
Longitude -133.27437
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Gold prospect is about 0.3 mile south of hill 4330 which is locally called 'Spruce Mountain'. The shaft at the prospect is about 0.5 mile east-northeast of the center of section 31, T. 49 S., R. 76 E.

Geologic setting

Geologic description

The Gold prospect is one of several prospects and mineral occurrences (SD046-049) in what is often referred to as the Third Zone of Spencer (1906; Kimble and others, 1984). These are generally gold-quartz veins and veinlets in muscovite schist of Cretaceous age (Brew and Grybeck, 1984).
The Gold prospect was known as early as 1915 and the claims on it were restaked in the 1930s and early 1940s (Kimble and others, 1984). The workings consist of a 20-foot shaft and a 156-foot trench. Of the samples collected by Kimble and others, the most notable was a 3.8-foot channel sample across a quartz vein that contained 2 parts per million (ppm) silver, 8 ppm gold, and 390 ppm lead. All of the samples contained 0.5 to 2 ppm silver. Nearby, on the Gold Shaft claim, an 8-foot thick quartz veins that strikes N 24 W and dips 80 SW is exposed in the talus. Samples across the vein contained only traces of gold and silver. However, a select sample from a pod of galena about 0.1 foot long in the quartz vein contained 30 ppm silver, 0.25 ppm gold, and 8,000 ppm lead.
The deposits at the nearby Marty prospect (SD041) and the Sumdum Chief Mine (SD028) have been dated at about 55 million years (Goldfarb and others, 1997). This prospect is geologically similar and probably of the same age. Goldfarb and others (1997) also propose that most gold-quartz vein deposits along the Juneau Gold Belt such as this one were formed from fluids generated by Cretaceous metamorphism and then forced to the site of deposition by the emplacement of the Coast Range Batholith.
Geologic map unit (-133.276075250993, 57.5790601914684)
Mineral deposit model Low-sulfide gold-quartz vein (Cox and Singer, 1986; model 36a).
Mineral deposit model number 36a
Age of mineralization The deposits at the nearby Marty prospect (SD041) and the Sumdum Chief Mine (SD028) have been dated at about 55 million years (Goldfarb and others, 1997). This prospect is geologically similar and probably of the same age.

Production and reserves

Workings or exploration The Gold prospect was known as early as 1915 and the claims on it were restaked in the 1930s and early 1940s (Kimble and others, 1984). The workings consist of a 20-foot shaft and a 156-foot trench. Sampled by government geologists in the early 1980s (Kimble and others, 1984).
Indication of production None

Additional comments

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

References

MRDS Number A013351

References

Goldfarb, R.J., Miller, L.D., Leach, D.L., and Snee, L.W, 1997, Gold deposits in metamorphic rocks in Alaska, in Goldfarb, R.J., and Miller, L.D., eds., Mineral Deposits of Alaska: Economic Geology Monograph 9, p. 151-190.
Redman, Earl, 1988, History of the mines and miners in the Juneau gold belt: Juneau, Alaska, privately printed, 294 p.
Reporters Donald Grybeck (U.S. Geological Survey)
Last report date 10/8/2004