Unnamed (in upper Three Mile Creek)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Ag; Au; Cu
Other commodities As
Ore minerals arsenopyrite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale CR
Quadrangle map, 1:63,360-scale C-3
Latitude 55.54291
Longitude -132.93945
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is along a logging road at an elevation of about 1,800 feet, about 1.4 miles southwest of peak 3640. It is in about the center of the NW1/4 section 15, T. 73 S., R. 82 E.

Geologic setting

Geologic description

The occurrence consists of an arsenopyrite-quartz vein about 18 inches thick that cuts argillite of the Luck Creek Breccia of Silurian and Devonian age (Hedderly-Smith and Glavinovich, 1991; D.J. Grybeck, unpublished field notes, 1984). The vein is mainly quartz but a layer about 1.5 inches thick has about 10 percent sulfides, mainly arsenopyrite. Samples contained 0.46 percent copper and up to 17 parts per million (ppm) silver and 1.390 ppm gold. The deposit may be related to a nearby or buried Cretaceous granitic intrusion (Eberlein and others, 1983; Brew, 1996).
Geologic map unit (-132.941109974052, 55.542555650184)
Mineral deposit model Polymetallic vein (Cox and Singer, 1986, model 22c).
Mineral deposit model number 22c
Age of mineralization Possibly related to a nearby or buried Cretaceous granitic intrusion.

Production and reserves

Indication of production None

Additional comments

The Sealaska Corporation holds the subsurface rights to the land in the vicinity of this occurrence.

References

References

Hedderly-Smith, D.A., 1991, Report of the 1990 work in the T75S, R83E, and T75S, R84E-Sealaska minerals reconnaissance project: Sealaska Corportion (Unpublished report held by the Sealaska Corporation, Juneau, Alaska.)
Hedderly-Smith, D.A., 1992, Report of the 1991 field season - Sealaska Mineral Reconnaissance Project: Sealaska Corporation, 2 vols., 225 p. 23 plates. (Unpublished report held by the Sealaska Corporation, Juneau, Alaska.)
Hedderly-Smith, D.A., 1993, Report of the 1992 field season-Sealaska minerals reconnaissance project: Sealaska Corporation, 60 p. (Unpublished report held by the Sealaska Corporation, Juneau, Alaska.)
Hedderly-Smith, D.A., 1997, Report on the 1995 and 1996 work on the Kasaan Peninsula-Sealaska minerals project: Sealaska Corporation, 87 p. (Unpublished report held by the Sealaska Corporation, Juneau, Alaska.)
Hedderly-Smith, D.A., 1997, Results of the 1996 upper Harris River stream sediment sampling-Sealaska minerals reconnaissance project: Sealaska Corporation, 9 p. (Unpublished report held by the Sealaska Corporation, Juneau, Alaska.)
Hedderly-Smith, D.A., 1999, Inventory of metallic mineral prospects, showings and anomalies on Sealaska lands, 1988 through 1998: Sealaska Corporation, Juneau, Alaska, 217 p. (internal report held by Sealaska Corporation, Juneau, Alaska).
Hedderly-Smith, D.A., and Glavinovich, P.S., 1991; Moss-mat stream sediment sampling in the Threemile Creek-Black Lake area, southeastern Alaska: Explore, no. 71, p. 14-17.
Reporters D.J. Grybeck (Applied Geology)
Last report date 5/1/2004