|Quadrangle map, 1:250,000-scale||TI|
|Quadrangle map, 1:63,360-scale||D-2|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This site is a part of a 30-mile stretch of beach exhibiting patchy, small concentrations of finely-divided placer gold. Approximately 8 miles of this beach is within the Trinity Islands quadrangle, extending from northwest of the Low Cape triangulation station southeast to beyond Gump triangulation station (Cobb, 1972, MF 468, locality 2; Cobb, 1973, Bulletin 1374, figure 11, locality 1; MacKevett and Holloway, 1977, locality 1). Although there has been mining and prospecting activity within this section of beach, most descriptions apply to the more extensive beach to the northwest in the Karluk quadrangle (see ARDF KR030).|
Placer gold deposits on the west coast of Kodiak Island have been worked since the early 1890s (Becker, 1897, p. 86); however, mining activity has been sporadic at best. The latest reported mining or prospecting work was done by 2 men in 1950-52 (Cobb, 1973, Bulletin 1374). Cobb estimates that total gold production is probably not more than a few thousand ounces. Concentrations of gold and other heavy minerals tend to occur in small, thin patches which appear and disappear according to variability of wave action and tides. No well-defined pay streaks occur. Approximately 95 percent of these beach concentrates is magnetite; the remainder consists of pyrite, chromite, and a little gold and platinum. No estimates of gold values within these patchy zones of heavy minerals have been reported. The immediate source of the gold appears to be the nearby bluffs of glacial gravels and tills, which are constantly being eroded by wave action. The gold content of the glacial deposits is extremely low as shown by the lack of visible gold where they have been prospected.An analysis of placer PGE concentrate from the beach (Maddren, 1919, p. 316) is as follows: 26.9 percent iridium-osmium, rhodium; 6.1 percent iridium from part of iridium-osmium; 0.1 percent rhodium from part of iridium-osmium; 55.3 percent platinum; 2.4 percent iridium; 6.4 percent iron; 0.3 percent gold; 0.7 percent rhodium; 0.1 percent palladium; 0.6 percent copper; 0.08 percent nickel; trace silver and zinc.
|Geologic map unit||(-154.44230468081, 56.9792175787854)|
|Mineral deposit model||Gold-PGE placer (Cox and Singer, 1986; model 39a).|
|Mineral deposit model number||39a|
|Age of mineralization||Quaternary|
|Workings or exploration||These deposits have been worked sporadically using small portable rockers and sluice boxes.|
|Indication of production||Yes; small|
Additional commentsDescriptions of beach placers in the Kodiak region are so generalized that it is difficult to discern which descriptions are pertinent to any given location.
Cobb, E.H., 1972, Metallic mineral resources map of the Trinity Islands quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF- 468, 1 sheet, scale 1:250,000.
Cobb, E.H., 1979, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Afognak, Karluk, Kodiak, and Trinity Islands quadrangles, Alaska: U.S. Geological Survey Open-File Report 79-860, 49 p.
MacKevett, E.M., Jr., and Holloway, C.D., 1977, Map showing metalliferous mineral deposits in the western part of southern Alaska: U.S. Geological Survey Open-File Report 77-169-F, 38 p., 1 sheet, scale 1:1,000,000.
Maddren, A.G., 1919, The beach placers of the west coast of Kodiak Island, Alaska, in Martin, G.C., and others, Mineral resources of Alaska, 1917: U.S. Geological Survey Bulletin 692-E, p. 299-319.
McGee, D.L., 1972, Kodiak Island and vicinity, Alaska: Geology and mineral resources: Alaska Division of Geological & Geophysical Surveys Alaska Open-File Report 31, 7 p., 1 sheet, scale 1:250,000.
|Reporters||S.H. Pilcher (Anchorage)|
|Last report date||8/28/1992|