Gold Standard

Prospect, Active?

Commodities and mineralogy

Main commodities Au
Other commodities Pb
Ore minerals arsenopyrite; galena; gold; pyrite
Gangue minerals ankerite; calcite; quartz

Geographic location

Quadrangle map, 1:250,000-scale JU
Quadrangle map, 1:63,360-scale C-3
Latitude 58.6676
Longitude -134.8913
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Gold Standard prospect is near the south end of a ridge at an elevation of 1,700 feet, approximately 1/2 mile east of inner Echo Cove. It is in the northwest corner of section 17, T. 37 S., R. 64 E. of the Copper River Meridian. The location is accurate.

Geologic setting

Geologic description

The deposit at the Gold Standard prospect consists of quartz-calcite-siderite veins and stringer zones along the contact of greenstone and phyllite. The veins contain pyrite, arsenopyrite and galena. The veins are up to 2 feet thick, strike northerly, dip moderately to the east, and can be traced along strike for 4,500 feet . The deposit was discovered in 1897. Workings include 3 adits, one inclined shaft, and several open cuts and trenches. Samples contain up to 24.7 ppm gold (Redman and others, 1989). This prospect is on the same vein system as the California prospect (JU071).
This prospect is in the Juneau Gold Belt, which consists of more than 200 gold-quartz-vein deposits that have produced nearly 7 million ounces of gold. These gold-bearing mesothermal quartz vein systems form a zone 160 km long by 5 to 8 km wide along the western margin of the Coast Mountains. The vein systems are in or near shear zones adjacent to west-verging, mid-Cretaceous thrust faults. The veins are hosted by diverse, variably metamorphosed, sedimentary, volcanic, and intrusive rocks. From the Coast Mountains batholith westward, the host rocks include mixed metasedimentary and metavolcanic sequences of Carboniferous and older, Permian and Triassic, and Jurassic-Cretaceous age. The sequences are juxtaposed along mid-Cretaceous thrust faults (Miller and others, 1994). The sequences are intruded by mid-Cretaceous to middle Eocene plutons, mainly diorite, tonalite, granodiorite, quartz monzonite, and granite. Sheetlike tonalite plutons emplaced just east of the Juneau Gold Belt and undeformed granite and granodiorite bodies that are emplaced farther to the east are between 55 and 48 Ma (Gehrels and others, 1991). The structural grain of the belt is defined by northwest-striking, moderately to steeply northeast-dipping, penetrative foliation that developed between Cretaceous and Eocene time (Miller and others, 1994). The majority of the veins in the Juneau Gold Belt strike northwest. Isotopic dates indicate that the auriferous veins in the Juneau Gold Belt formed between 56 and 55 Ma (Miller and others, 1994; Goldfarb and others, 1997).
Geologic map unit (-134.893092325127, 58.6672780005312)
Mineral deposit model Low-sulfide Au-quartz vein (Cox and Singer, 1986; model 36a)
Mineral deposit model number 36a
Age of mineralization Isotopic dates indicate that the auriferous veins in the Juneau Gold Belt formed between 56 and 55 Ma (Miller and others, 1994; Goldfarb and others, 1997).

Production and reserves

Workings or exploration The deposit was discovered in 1897. Workings include 3 adits, one inclined shaft, and several open cuts and trenches.
Indication of production None

References

MRDS Number A012023

References

Gehrels, G.E., McClelland, W.C., Samson, S.D., and Patchett, P.J., 1991, U-Pb geochronology of detrital zircons from a continental margin assemblage in the northern Coast Mountains, southeastern Alaska: Canadian Journal of Earth Sciences, v. 28, no. 8, p.1285-1300.
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.
Miller, L.D., Goldfarb, R.J., Gehrels, G,E., and Snee, L.W., 1994, Genetic links among fluid cycling, vein formation, regional deformation, and plutonism in the Juneau gold belt, southeastern Alaska: Geology, v. 22, p. 203-206.
Reporters J.C. Barnett and L.D. Miller (Juneau, Alaska )
Last report date 12/15/2001