|Quadrangle map, 1:250,000-scale||LC|
|Quadrangle map, 1:63,360-scale||A-3|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||Locality is at the top of a 1,829 m (6,000 ft) peak 4.8 km NE of the eastern end of Kontrashibuna Lake. The anomaly extends at least 1.6 km around the location. This is locality 34 of Nelson and others (1985) and locality 31 of MacKevett and Holloway (1977). Sec. 17, T. 1 N., R. 26 W., of the Seward Meridian. Accurate within 1,500 meters.|
Widespread, mostly low-grade mineralization associated with metamorphic rocks (roof pendant) and volcanic rocks in vicinity of Tertiary granite. Chalcopyrite occurs as thin fracture coatings or within quartz veins in shear zones (Nelson and others, 1985). Sulfide mineralization best developed in the meta-siltstone and argillite near andesite or diorite contact. Maximum values from rock chip samples yielded: 27.7 ppm Ag, 0.32 percent Cu, 0.09 percent Pb, 75 ppm Sn, and 0.1 percent Zn (Nelson and others, 1985).
Three close-spaced southwest flowing streams, about 3.2 km SW of this location is sample 'Area D' of Eakins (1970). These streams flow through basalt into the eastern end of Kontrashibuna Lake. Stream sediment samples reported by Eakins (1970) yielded up to 95 ppm Pb and 225 ppm Zn. Copper values were below 50 ppm.Nelson and others (1983, units Ti8 and Tv) describe the rocks in this area as Tertiary medium-grained biotite-hornblende granodiorite which also includes granite and quartz monzodiorite; and Tertiary volcanic rocks that include rhyolitic breccia, ash-flow tuff, flows, and felsic intrusive rocks, and subordinate mafic to intermediate flows.
|Geologic map unit||(-153.832197346563, 60.1793426541231)|
|Mineral deposit model||Polymetallic vein (Cox and Singer, 1986; model 22c)|
|Mineral deposit model number||22c|
|Age of mineralization||Tertiary or younger|
|Alteration of deposit||Sericitic, argillic, and chloritic alteration.|
|Workings or exploration||Maximum values from rock chip samples yielded: 27.7 ppm Ag, 0.32 percent Cu, 0.09 percent Pb, 75 ppm Sn, and 0.1 percent Zn (Nelson and others, 1985). Stream sediment samples reported by Eakins (1970) yielded up to 95 ppm Pb and 225 ppm Zn. Copper values were below 50 ppm.|
|Indication of production||None|
|Reserve estimates||No reserves|
|Production notes||No production|
Additional commentsSite is in Lake Clark National Park and Preserve.
Eakins, G.R., 1970, Geology and geochemistry of Kontrashibuna Lake, Lake Clark region, southwestern Alaska: Alaska Division of Mines and Geology Geochemical Report 20, 34 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.
Nelson, W.H., Carlson, C., and Case, J.E., 1983, Geologic map of the Lake Clark quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-1114-A, 1 sheet, scale 1:250,000.
Nelson, W.H., King, H.D., Case, J.E., Tripp, R.B., Crim, W.D., and Cooley, E.F., 1985, Mineral resource map of the Lake Clark quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-1114-B, 1 sheet, scale 1:250,000.
Resource Associates of Alaska, Inc., 1976, Geology and geochemistry of certain land within the Lake Clark National Park: Contract report for U.S. Bureau of Mines, Contract JO166108, 7 v.
|Reporters||M.L. Miller (USGS); D.P. Bickerstaff (USGS)|
|Last report date||6/15/1998|