Journal cover Journal topic
Climate of the Past An interactive open-access journal of the European Geosciences Union
Clim. Past, 9, 1933-1947, 2013
https://doi.org/10.5194/cp-9-1933-2013
© Author(s) 2013. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
16 Aug 2013
Petrophysical characterization of the lacustrine sediment succession drilled in Lake El'gygytgyn, Far East Russian Arctic
A. C. Gebhardt1, A. Francke2, J. Kück3, M. Sauerbrey2, F. Niessen1, V. Wennrich2, and M. Melles2 1Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Columbusstraße, 27515 Bremerhaven, Germany
2University of Cologne, Institute of Geology and Mineralogy, Zülpicher Straße 49A, 50674 Cologne, Germany
3German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany
Abstract. 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).

Citation: Gebhardt, A. C., Francke, A., Kück, J., Sauerbrey, M., Niessen, F., Wennrich, V., and Melles, M.: Petrophysical characterization of the lacustrine sediment succession drilled in Lake El'gygytgyn, Far East Russian Arctic, Clim. Past, 9, 1933-1947, https://doi.org/10.5194/cp-9-1933-2013, 2013.
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