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| Titel |
Petrophysical characterization of the lacustrine sediment succession drilled in Lake El'gygytgyn, Far East Russian Arctic |
| VerfasserIn |
A. C. Gebhardt, A. Francke, J. Kück, M. Sauerbrey, F. Niessen, V. Wennrich, M. Melles |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1814-9324
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| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 9, no. 4 ; Nr. 9, no. 4 (2013-08-16), S.1933-1947 |
| Datensatznummer |
250085206
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| Publikation (Nr.) |
 copernicus.org/cp-9-1933-2013.pdf |
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| Zusammenfassung |
| Seismic profiles of Far East Russian Lake El'gygytgyn, formed by a meteorite
impact some 3.6 million years ago, show a stratified sediment succession
that can be separated into subunits Ia and Ib at approximately 167 m below
lake floor (=~3.17 Ma). The upper (Ia) is well-stratified, while
the lower is acoustically more massive and discontinuous. The sediments are
intercalated with frequent mass movement deposits mainly in the proximal
areas, while the distal region is almost free of such deposits at least in
the upper part. In spring 2009, a long core drilled in the lake center
within the framework of the International Continental Scientific Drilling
Program (ICDP) penetrated the entire lacustrine sediment succession down to
~320 m below lake floor and about 200 m farther into the
meteorite-impact-related bedrock. Downhole logging data down to 390 m below
lake floor show that the bedrock and the lacustrine part differ
significantly in their petrophysical characteristics. The contact between
the bedrock and the lacustrine sediments is not abrupt, but rather
transitional with a variable mixture of impact-altered bedrock clasts in a
lacustrine matrix. Physical and chemical proxies measured on the cores can
be used to divide the lacustrine part into five different statistical
clusters. These can be plotted in a redox-condition vs. input-type diagram,
with total organic carbon content and magnetic susceptibility values
indicating anoxic or oxic conditions and with the Si / Ti ratio representing
more clastic or more biogenic input. Plotting the clusters in this diagram
allows identifying clusters that represent glacial phases (cluster I), super
interglacials (cluster II), and interglacial phases (clusters III and IV). |
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