|Quadrangle map, 1:250,000-scale||LC|
|Quadrangle map, 1:63,360-scale||C-3|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||About 2.1 km north of the eastern arm of Twin Lakes on peak 5,280. The 1.3 km wide, oval-shaped occurrence extends approximately 7.3 km S-SE across Twin Lakes, terminating near peak 5,570. Corresponds with locality 11 of Nelson and others (1985) and locality 21 of MacKevett and Holloway (1977). Sec. 22, T. 7 N., R. 26 W., of the Seward Meridian. Longitude and latitude of occurrence is accurate within 1,200 m.|
Geologic descriptionMineralization occurs as fine-grained disseminations and hairline fracture fillings of pyrite and lesser chalcopyrite, sphalerite, and galena in silicified rhyolite and rhyolite-dacite volcanic rocks and breccias (Nelson and others, 1983). Resource Associates of Alaska (1976) considered the setting as a possible volcanic vent center. These rocks have undergone epidote and chlorite alteration, silicification, and lesser sericitization. The volcanic rocks have potassium-argon ages that range from 56.2 to 62.7 m.y. (Eakins and others, 1978).
|Geologic map unit||(-153.832258701794, 60.6793369735209)|
|Mineral deposit model||Polymetallic vein? (Cox and Singer, 1986; model 22c?).|
|Mineral deposit model number||22c?|
|Age of mineralization||The volcanic rocks that host the mineralization have potassium-argon ages that range from 56.2 to 62.7 m.y. (Eakins and others, 1978).|
|Alteration of deposit||The volcanic rocks have undergone epidote and chlorite alteration, silicification, and lesser sericitization.|
|Indication of production||None|
|Reserve estimates||No reserves|
|Production notes||No production|
Additional commentsSite is in Lake Clark National Park and Preserve.
|MRDS Number||A013025; A013026|
Cobb, E.H., and Reed, B.L., 1981, Summaries of data on and lists of references to metallic and selected nonmetallic mineral occurrences in the Iliamna, Lake Clark, Lime Hills, and McGrath quadrangles, Alaska; Supplement to Open-File Report 76-485; Part A, Summaries to January 1, 1981: U.S. Geological Survey Open-File Report 81-1343-A, 25 p.
Cobb, E.H., and Reed, B.L., 1981, Summaries of data on and lists of references to metallic and selected nonmetallic mineral occurrences in the Iliamna, Lake Clark, Lime Hills, and McGrath quadrangles, Alaska; Supplement to Open-File Report 76-485; Part B, Lists of references to Januray 1, 1981: U.S. Geological Survey Open-File Report 81-1343-B, 20 p.
Eakins, G.R., Gilbert W.G., and Buntzen, T.K., 1978, Preliminary bedrock geology and mineral resource potential of west-central Lake Clark quadrangle, Alaska: Alaska Division of Geological and Geophysical Surveys Open-File Report 118, 15 p., 2 plates, scale 1:25,000.
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., 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|