Kougarok

Alaska, United States

TinTantalum

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Commodities

PrimaryTin

SecondaryTantalum

Deposit

Model49: Sn greisen

Materials

Ore mineralsCassiterite, Columbite, Tantalite

GangueArsenopyrite, Fluorite, Quartz, Topaz, Tourmaline, Mica

Geology

AlterationHydrothermal alteration is extensive in the Kougarok prospect area. The country rock metapelitic schist and hornfels is extensively veined and replaced by tourmaline, axinite, and sulfide minerals (dominately pyrrhotite but including arsenopyrite and chalcopyrite) over a roughly circular area with a diameter of 3,700 feet at the surface and to a depth of almost 800 feet in the area above the zinnwaldite granite and between Chuck's dike and the Main plug (Puchner, 1986). Tin is commonly anomalous in these rocks and in places exceeds 0.1%. Sericite and tourmaline development is ubiquitous in granite intrusions of the prospect area. Puchner (1986) recognizes increasing degrees of alteration from weak sericite-tourmaline replacement to assemblages with increasing zinnwaldite contents to quartz-tourmaline-topaz greisen. Zinnwaldite-rich alteration zones peripheral to roof greisen are common.

Economic & production

Development statusProspect

Identification

Deposit ID10308430

RegionNA

Data scoreB

Coordinates65.71032, -165.22941

References

Cobb, E.H., and Sainsbury, C.L., 1972, Metallic mineral resource map of the Teller quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-426, 1 sheet, scale 1:250,000.Marsh, W.R., Sainsbury, C.L., Hamilton, J.C., and Ewing, Rodney, 1972, Tin in panned concentrates, Serpentine River, Seward Peninsula, Alaska: U.S. Geological Survey Open-File Report 536, 7 p.Barnes, D.F., and Hudson, T. L., 1977, Bouguer gravity map of Seward Peninsula, Alaska: U.S. Geological Survey Open-File Report 77-796-C, scale 1:1,000,000.Hudson, T.L., and Arth, J. G., 1983, Tin-granites of Seward Peninsula, Alaska: Geological Society of America Bulletin, v. 94, p. 768-790.Gardner, M.C., and Hudson, T.L., 1984, Structural geology of Precambarian and Paleozoic metamorphic rocks, Seward terrane, Alaska [abs.]: Geological Society of American, Abstracts with Programs, v. 16, p. 285.Puchner, C.C., 1984, 1983 Annual report; Kougarok Project: Anchorage, Alaska, Anaconda Minerals Company internal report (Report held by Cook Inlet Region, Inc., Anchorage, Alaska).Puchner, C.C., 1986, Geology, alteration, and mineralization of the Kougarok Sn deposit, Seward Peninsula, Alaska; Discussion reply: Economic Geology, v. 82, p. 2201-2204.Cobb, E.H., 1975, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Teller quadrangle, Alaska: U.S. Geological Survey Open-File Report 75-587, 130 p.Gardner, M.C., and Hudson, T.L., 1984, Structural geology of Precambarian and Paleozoic metamorphic rocks, Seward terrane, Alaska [abs.]: Geological Society of American, Abstracts with Programs, v. 16, no. 5, p. 285.