|Quadrangle map, 1:250,000-scale||CR|
|Quadrangle map, 1:63,360-scale||A-2|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This is an old prospect that seems to have been overlooked in the literature until recently. The only published location for it lacks precision but it is probably within a half mile of a site near sea level, about 1.0 mile northeast of Nutkwa Point, in the north half of section 26, T. 78 S., R. 85 E.|
Geologic descriptionIn 1993, American Copper and Nickel Company (ACNC) rediscovered this old prospect, which consists of a 70-foot adit and a prospect pit (Hedderly-Smith, 1999 [Inventory]). Samples across 2 feet of mineralized rock in the old workings contained 25 percent zinc, 2.6 percent copper, 0.6 percent lead, 1.29 ounce of silver per ton, and 0.10 ounce of gold per ton. After they located the old workings, ACNC mapped the geology of the area, carried out soil sampling and shallow geophysical surveys, and drilled five holes. The deposit is a massive-sulfide horizon that strikes N25E and dips 5-15SE; it varies from less than inch to over three feet thick, and has an average thickness of 1 to 2 feet over a strike length of 1,200 feet. The grade of the horizon averages 20-27 percent zinc, about 1 percent copper, 0.7 to 5 ounces of silver per ton, and 0.007 to 0.4 ounce of gold per ton. ACNC continued to work in the area in 1994 and 1995 and explored the extension of the mineralization into section 24. The rocks in the area are part of the Wales Group of Late Proterozoic and Cambrian age; they consist of greenstone, greenschist, phyllite, quartz-sericite schist, and minor marble (Eberlein and others, 1983; Brew, 1996).
|Geologic map unit||(-132.554393854144, 55.0797581487075)|
|Mineral deposit model||Volcanogenic massive-sulfide deposit (Cox and Singer, 1986; model 28a).|
|Mineral deposit model number||28a|
|Age of mineralization||Probably coeval with the deposition of the Late Proterozoic or Cambrian host rocks.|
|Alteration of deposit||The alteration is probably similar to that associated with typical volcanogenic massive-sulfide mineralization.|
|Workings or exploration||The old workings include an adit and a prospect pit. American Copper and Nickel Company did considerable work in the area from 1993 to 1995. It included geologic mapping and soil and geophysical surveys, and they drilled 5 holes.|
|Indication of production||None|
Additional commentsThis old prospect is on land that has been conveyed to the Sealaska Corporation, who hold the surface and subsurface rights, or the land is under application for transfer to them.
Brew, D.A., 1996, Geologic map of the Craig, Dixon Entrance, and parts of the Ketchikan and Prince Rupert quadrangles, southeastern Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-2319, 53 p., 1 sheet, scale 1:250,000.
Eberlein, G.D., Churkin, Michael, Jr., Carter, Claire, Berg, H.C., and Ovenshine, A. T., 1983, Geology of the Craig quadrangle, Alaska: U.S. Geological Survey Open-File Report 83-91, 52 p.
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|