Unnamed (near 'Jesse Lake')

Prospect, Undetermined

Commodities and mineralogy

Main commodities Ag; Au; Cu; Pb; Zn
Ore minerals chalcopyrite; hematite; magnetite; pyrite; pyrrhotite; sphalerite
Gangue minerals epidote; garnet; quartz

Geographic location

Quadrangle map, 1:250,000-scale CR
Quadrangle map, 1:63,360-scale A-1
Latitude 55.17516
Longitude -132.04527
Nearby scientific data Find additional scientific data near this location
Location and accuracy This site includes scattered occurrences of skarn mineralization in the S1/2 of sections 19 and 20, T. 77 S., R. 89 E. They are near a small lake informally called Jesse Lake in the literature. The coordinates are at about the center of the area of occurrences.

Geologic setting

Geologic description

Sealaska geologists discovered skarn mineralization at this site in 1988 Hedderly-Smith (1999 [Inventory]). The rocks in the area are chlorite schist and greenstone, interbedded with minor limestone, that are part of the Wales Group of Late Proterozoic and Cambrian age (Eberlein and others, 1983; Brew, 1996). The skarn largely consists of quartz, epidote, garnet, and magnetite, with hematite, pyrite, pyrrhotite, chalcopyrite, and sphalerite. Six of Hedderly-Smith's skarn samples contained up to 6,280 parts per million (ppm) copper, 105 ppm lead, 8,630 ppm zinc, 9.2 ppm silver, and 137 parts per billion (ppb) gold. Maas and others (1991) collected a sample of gossan rubble from a borrow pit in the SW1/4 of section 20 that contained 171 ppm copper, 1.4 ppm silver, and 1,686 ppb gold. A sample of pyrite from a boulder collected about 1,500 feet northwest of Jesse Lake contained 102 ppm copper, 2.9 ppm silver, and 6.243 ppb gold. Hale and others (1992) noted stratiform sulfides in four widely spaced borrow pits in the Jesse Lake area; they suggested that they were replacement deposits in carbonate pods in volcaniclastic sedimentary rocks. Three short drill holes in the mineralized outcrops did not encounter additional mineralization.
Geologic map unit (-132.046942084185, 55.1748046875331)
Mineral deposit model Au-Cu-Zn skarn; stratiform replacement deposits in carbonate pods.
Age of mineralization Younger than the Late Proterozoic or Cambrian host rocks.
Alteration of deposit Skarns in carbonate rocks.

Production and reserves

Workings or exploration Mainly surface examination and sampling of outcrops by government and industry geologists. Three short drill holes in the mineralized outcrops did not encounter additional mineralization.
Indication of production None

References

References

Hale, C., Kruger, F.C., and Salisbury, W.G., 1992, Dolomi-Kael project, Prince of Wales Island, Alaska, 1991 Annual Report: American Copper and Nickel Company, 20 p. plus appendices (Unpublished report held by Sealaska Corporation, Juneau, Alaska).
Hedderly-Smith, D.A., 1989, Report of the 1988 field season - Sealaska Mineral Reconnaissance Project: Sealaska Corporation, 66 p. (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, Gold-copper mineralization in the Dolomi-Chasina Point area, Prince of Wales Island, Alaska (abs.): Alaska Miners Association, Juneau Branch, Conference Juneau, Abstracts of Professional Papers, p. 13-14.
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).
Reporters D.J. Grybeck (Applied Geology)
Last report date 5/1/2004