Greenpoint (ARDF #BC023) Ag, Cu, Mo, Pb

Greenpoint

Prospect, Inactive

Commodities and mineralogy

Main commodities	Ag; Cu; Mo; Pb
Ore minerals	chalcopyrite; galena; molybdenite; pyrite
Gangue minerals	calcite; quartz

Geographic location

Quadrangle map, 1:250,000-scale	BC
Quadrangle map, 1:63,360-scale	A-1
Latitude	56.025
Longitude	-130.322
Nearby scientific data	Find additional scientific data near this location
Location and accuracy	The Greenpoint prospect is at an elevation of about 2700 feet on an untimbered point about 750 feet south of the confluence of Greenpoint and Through glaciers (Berg and others, 1977, p. 93-96; Elliott and Koch, 1981, p. 10, loc. 23). The location is probably accurate to within about a quarter of a mile. Also see Additional Comments field, below.

Geologic setting

Geologic description The country rocks in the area of the Greenpoint prospect are pelitic metasedimentary and andesitic metavolcanic rocks of the Jurassic or older Mesozoic Hazelton Group, and quartz monzonite and granodiorite of the Eocene Hyder Quartz Monzonite (Berg and others, 1977, p. 15-17, 22-23; Smith, 1977; Koch, 1996). The deposit (Berg and others, 1977, p. 93-96) consists of numerous quartz-calcite fissure veinlets up to 6 inches thick in multiple fracture sets that cut pelitic hornfels of the Hazelton Group. The veinlets contain up to 5 percent pyrite, lesser amounts of galena and molybdenite, and traces of chalcopyrite. Chip samples of the veinlets collected in 1972 by U.S. Bureau of Mines investigators contained as much as 30 ppm Ag. Average metal content was 2.4 ppm Ag, 400 ppm Pb, and 65 ppm Mo. One sample assayed 1100 ppm Zn.
Geologic map unit	(-130.32370538856, 56.024684280176)
Mineral deposit model	Polymetallic veins (Cox and Singer, 1986; model 22c).
Mineral deposit model number	22c

Production and reserves

Workings or exploration	Explored, probably in 1920s, by a small pit and open cut. Chip samples of veinlets collected in 1972 by the U.S. Bureau of Mines averaged 2.4 ppm Ag, 400 ppm Pb, and 65 ppm Mo. One sample contained 30 ppm Ag, and one assayed 1100 ppm Zn.
Indication of production	None
Additional comments The Greenpoint claims staked in 1970 (Berg and others, 1977, p. 94) extend beyond the Greenpoint prospect described in this record and cover the old Heckla prospect, which is described separately (BC024). Site is in Misty Fiords National Monument.

References

MRDS Number	A010309
References Berg, H.C., Elliott, R.L., Smith, J.G., Pittman, T.L., and Kimball, A. L., 1977, Mineral resources of the Granite Fiords Wilderness Study Area, Alaska, with a section on aeromagnetic data by Andrew Griscom: U.S. Geological Survey Bulletin 1403, 151 p. Smith, J.G., 1977, Geology of the Ketchikan D-1 and Bradfield Canal A-1 quadrangles, Alaska: U.S. Geological Survey Bulletin 1425, 49 p., 1 plate.
Reporters	H. C. Berg (Fullerton, California)
Last report date	5/17/1998