Quadrangle map, 1:250,000-scale | LC |
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Quadrangle map, 1:63,360-scale | B-5 |
Latitude | 60.41 |
Longitude | -154.55 |
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. |
Geologic descriptionWeak 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) |
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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. |
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Indication of production | None |
Reserve estimates | No reserves |
Production notes | No production |
Additional commentsSite is in Lake Clark National Park and Preserve. |
MRDS Number | A106361 |
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ReferencesResource 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.
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Reporters | D.P. Bickerstaff (USGS) |
Last report date | 6/15/1998 |