|Quadrangle map, 1:250,000-scale||LC|
|Quadrangle map, 1:63,360-scale||B-5|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||An extensive arcuate shaped occurrence centered approximately at a point 8 km upstream from the mouth of an unnamed northwest flowing tributary of the Koksetna River. The occurrence extends roughly 6.5 km northwest and 8 km south of this location and is about 2.9 km wide. Locality 15 of Nelson and others (1985) and locality 23 of MacKevitt and Holloway (1977). Sec. 30, T. 4 N., R. 30 W., of the Seward Meridian. Locality accurate within 1.6 km.|
Weak geochemical anomalies associated with granite and rhyolite that may include breccia pipes. Granite is less fractured and iron-stained than rhyolite (Nelson and others, 1985).The granite is part of the numerous, mostly quartz monzonite intrusive bodies found in the central part of the Lake Clark 1:250,000 scale quadrangle mapped and identified by Eakins and others (1978); (Nelson and others, 1983; unit TKi5). One of these plutons yielded a potassium-argon biotite age of 71.3 +/- 2.1 m.y. (Eakins and others, 1978). The rhyolite is part of unit Tv. Unit Tv is described by Nelson and others (1983) to include: rhyolitic breccia, ash-flow tuff, flows, and intrusive rocks and subordinate mafic to intermediate flows. Potassium-argon ages for this unit (Tv) range from 56.2 to 62.7 m.y. indicating a Tertiary age for these rocks (Eakins and others, 1978).
|Geologic map unit||(-154.552230967756, 60.4093279707273)|
|Mineral deposit model||Porphyry Cu-Mo? (Cox and Singer, 1986; model 21a?).|
|Mineral deposit model number||21a?|
|Age of mineralization||Late Cretaceous or younger. Rocks of the quartz monzonite unit yielded a potassium-argon biotite age of 71.3 +/- 2.1 m.y. (Eakins and others, 1978). Potassium-argon ages for the rhyolite, unit Tv, range from 56.2 to 62.7 m.y. (Eakins and others, 1978)|
|Alteration of deposit||Unknown|
|Workings or exploration||Unknown, although Resource Associates of Alaska (1976) completed a sampling program that identified the occurrence.|
|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., 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., 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||D.P. Bickerstaff (USGS)|
|Last report date||6/15/1998|