Unnamed Occurrence (ARDF - PM012; west of Knutson Lake), Alaska Peninsula District, Aleutians East Borough, Alaska, USA

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This site is located on state land.
Location: The map site of this occurrence is at an elevation of 1,600 feet, approximately 1 mile west of Knutson Lake (Wilson and others, 1988, locality 88). The location is accurate to within 2,500 feet.
Geology: At this site a travertine deposit approximately 300 feet across and 40 feet thick has formed from seeps in fractures cutting sandstone and shale, either of the the Upper Cretaceous Hoodoo Formation (Trujillo and others, 1982) or the Lower Cretaceous Staniukovich Formation (Wilson and others, 1995). The travertine has a high arsenic content and traces of silver and gold. A pan sample taken from a stream draining the travertine contained visible galena and assayed 2.63 ppm gold, 17.5 ppm silver, and 2,003 ppm lead. Gossan from unmineralized fractures in sandstone slightly uphill from the travertine contained as much as 0.8 ppm gold, 4.3 ppm silver, 295 ppm lead, 366 ppm zinc, and 1.25 percent arsenic (Trujillo and others, 1982).
Workings: In 1982 Resource Associates of Alaska examined and sampled the site (Trujillo and others, 1982). A pan concentrate sample assayed 2.63 ppm gold, 17.5 ppm silver, and 2,003 ppm lead. Gossan from unmineralized fractures contained as much as 0.8 ppm gold, 4.3 ppm silver, 295 ppm lead, 366 ppm zinc, and 1.25 percent arsenic.
Age: Cretaceous or younger.

Commodities (Major) - Ag, Au, Pb; (Minor) - As, Zn
Development Status: None
Deposit Model: Hot-spring Au-Ag (Cox and Singer, 1986; model 25a)

References

Trujillo, R.S., Tapper, C.J., Alvarez, T.J., Porterfield, Ben, and Toupe, W.M., 1982, Exploration and evaluation of precious metal potential of portions of Aleut Corporation lands, southwest Alaska 1982: Resource Associates of Alaska unpublished report, 91 p, 33 maps, various scales. (Report held by the Aleut Corporation, Anchorage, Alaska.) Wilson, F.H., Detterman, R.L., Miller, J. W., and Case, J.E., 1995, Geologic map of the Port Moller, Stepovak Bay, and Simeonof Island quadrangles, Alaska: U.S. Geological Survey Miscellaneous Investigation Series Map I-2272, 1 sheet, scale 1:250,000. Wilson, F.H., White, W.H., and DuBois, G.D., 1988, Brief descriptions of mines, prospects, and mineral occurrences in the Port Moller and Stepovak Bay quadrangles, Alaska Peninsula: U.S. Geological Survey Open-File Report 88-666, 128 p., 1 plate, scale 1:250,000.

Mineral List

Calcite var: Travertine

Galena

Gold

3 entries listed. 2 valid minerals.