Unnamed (south of the Sullivan River)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Au; Co; Ni; Pb; Zn
Other commodities Co
Ore minerals chalcopyrite; pyrite; pyrrhotite
Gangue minerals calcite; quartz

Geographic location

Quadrangle map, 1:250,000-scale JU
Quadrangle map, 1:63,360-scale D-5
Latitude 58.8871
Longitude -135.4682
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is at an elevation of about 2,100 feet, on the east side of a north-facing glacier that is 1.5 miles south of the Sullivan River and approximately 4 miles SW of Lynn Canal. It is in the SE1/4 section 30, T. 34 S., R. 60 E. of the Copper River Meridian. The Sullivan River is not named on the current (1996) edition of the D-5 topographic map.

Geologic setting

Geologic description

This occurrence, called the south Sullivan River occurrence by the U.S. Bureau of Mines was discovered in 1988 by Bureau personnel following the extension of the lithologic units at the Dream prospect (JU009) to the south (Clough and Redman, 1989). The U.S. Geological Survey had previously noted elevated metal values in geochemical samples collected in the area in 1983 and 1984 (Bailey and others, 1985). The rocks in the area consist of graywacke, argillite and metavolcanic rocks. U.S. Bureau of Mines personnel sampled phyllite that contained up to 6000 ppm copper and siliceous argillite that contained up to 500 ppm zinc. They also sampled several quartz and quartz-calcite veins that contained up to 3.9 ppm gold, 22,000 ppm copper, 1,300 ppm cobalt, 1,300 ppm nickel, and 500 ppm zinc (Clough and Redman, 1989).
This deposit is one of many in the Dream prospect area that includes numerous veins, stockworks, stratabound and stratiform sulfide deposits (also see JU002, JU006, JU009, JU011, JU013, JU014, JU016, JU019), most of which occur near a volcaniclastic-marble contact. The U.S. Bureau of Mines (Clough and Redman, 1989), International Curator Resources, Ltd. (Huber and Barnett, 1988), and Placer Dome U.S. (Bull and others, 1989) explored the area in the late 1980s and developed a general lithology of the area. They divide the rocks into four major rock units. From the base up, they are: 1) a volcaniclastic unit approximately 2000 feet thick that consists of albite-chlorite schist, chlorite schist, and chlorite-quartz-sericite schist that may in part be metaplutonic as well as metavolcanic; 2) a unit 800 feet thick of micaceous marble, pelitic schist, graphite schist, gray to white, cliff-forming marble, chlorite-amphibole schist, greenstone, and phyllitic graphite schist; and 3) a unit of very fine-grained chlorite-sericite-biotite schist over 1000 feet thick that includes metatuff and pelitic, mafic and graphitic schist. The upper contact of this unit is a thrust fault that trends N-S for several miles; quartz veining is common along the thrust contact. The rocks overlying the thrust are middle- to upper-greenschist-facies graphitic schist, argillite, phyllite, and marble. The metamorphic grade of the rocks varies from mid- to upper-greenschist facies in the south, to amphibolite facies in the north. There have been at least two stages of folding.
The Dream prospect area was the site of extensive exploration and mapping from 1987 through 1990 by International Curator Resources Ltd. and Placer Dome U.S. The area was covered by 600 federal mining claims in 1989 and more than 5000 feet of drilling was completed by the end of 1990 (Swainbank and others, 1991).
The general area consists predominantly of metamorphosed Silurian and Devonian clastic rocks, limestone, and volcanic units; Permian limestone and siltstone; and small plutons of Tertiary and Cretaceous granodiorite (Brew and Ford, 1985).
Geologic map unit (-135.470049308982, 58.8867680624725)
Mineral deposit model Possibly a metamorphosed Kuroko massive sulfide deposit (Cox and Singer, 1986; model 28a) or a metamorphosed polymetallic replacement deposit (Cox and Singer, 1986; model 19a)
Mineral deposit model number 28a or 19a

Production and reserves

Workings or exploration Surface sampling only. The Dream prospect area was the site of extensive exploration and mapping from 1987 through 1990 by International Curator Resources Ltd. and Placer Dome U.S. The area was covered by 600 federal mining claims in 1989 and more than 5000 feet of drilling was completed by the end of 1990 (Swainbank and others, 1991).
Indication of production None

References

References

Bull, K.F., 1991, The Dream project--Model frustration: Journal of Alaska Miners Association, v. 19, no. 10, p. 17.
Bull, K.F., and Radford, G., 1989, Dream project 1989; Final report: Unpublished report for Placer Dome U.S., Inc., 49 p.
Huber, J.A., and Barnett, J.C., 1988, The Dream massive sulfide project; 1988 Progress Report: Unpublished report for International Curator Resources, Ltd., Denver, Colo., 51 p.
Reporters J.C. Barnett and L.D. Miller (Juneau, Alaska )
Last report date 12/15/2001