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East Takoka Creek

Occurrence, Inactive

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Commodities and mineralogy

Main commodities Cu
Other commodities Au
Ore minerals chalcopyrite; pyrite
Gangue minerals calcite; chlorite; epidote; quartz

Geographic location

Quadrangle map, 1:250,000-scale LC
Quadrangle map, 1:63,360-scale A-3
Latitude 60.16
Longitude -154.1
Nearby scientific data Find additional scientific data near this location
Location and accuracy About 2.8 km west of the Kasna Creek prospect near northward flowing Takoka Creek which drains into Kontrashibuna Lake. Locality 30 of Nelson and others (1985). Sec. 23, T. 1 N., R. 28 W., of the Seward Meridian. Locality accurate within 1.2 km.

Geologic setting

Geologic description

Local zones of fracturing and epidote or quartz-carbonate veins in greenstone contain chalcopyrite and pyrite. Some copper anomalies here may result from high initial copper in basic volcanic rocks (Nelson and others, 1985).
The Tertiary volcanic rocks of this unit includes: rhyolitic breccia, ash-flow tuff, flows, and intrusive rocks and subordinate mafic to intermediate flows (Nelson and others, 1983; unit Tv). Potassium-argon ages for 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 (-154.102197856349, 60.1593378006006)
Mineral deposit model Unknown
Age of mineralization Probably Tertiary. Volcanic host for mineralization has potassium-argon ages that range from 56.2 to 62.7 m.y. (Eakins and others, 1978).
Alteration of deposit Abundant chlorite, epidote, and sparse quartz-carbonate alteration.

Production and reserves

Workings or exploration Some copper anomalies in the area may result from high background copper in basic volcanic rocks (Nelson and others, 1985). Resource Associates of Alaska (1976) reported one soil sample which yielded 0.8 ppm Au. Area J of Eakins (1970) located approximately 2.6 km downstream contained stream sediment samples which yielded 130 ppm Cu; lead and zinc were not anomalous.
Indication of production None
Reserve estimates No reserves
Production notes No production

Additional comments

Gold anomaly in soil sample is only gold detected in the Kontrashibuna Lake area. Site is in Lake Clark National Park and Preserve.

References

MRDS Number A013014

References

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.
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.
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