Unnamed (west of Knutson Lake)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Ag; Au; Pb
Other commodities As; Zn
Ore minerals galena; gold
Gangue minerals travertine

Geographic location

Quadrangle map, 1:250,000-scale PM
Quadrangle map, 1:63,360-scale C-4
Latitude 55.627
Longitude -161.243
Nearby scientific data Find additional scientific data near this location
Location and accuracy 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.

Geologic setting

Geologic description

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).
Geologic map unit (-161.245019124043, 55.6261664183809)
Mineral deposit model Hot-spring Au-Ag (Cox and Singer, 1986; model 25a)
Mineral deposit model number 25a
Age of mineralization Cretaceous or younger.

Production and reserves

Workings or exploration 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.
Indication of production None

Additional comments

This site is located on state land.

References

MRDS Number 10308090

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precious metal potential of portions of Aleut Corporation lands, southwest Alaska 1982: Resource Associates of Alaska unpublished report, 91 p, 33 maps, various scales.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.)
Reporters S.H. Pilcher
Last report date 1/28/2001