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| Titel |
Inorganic geochemistry data from Lake El'gygytgyn sediments: marine isotope stages 6-11 |
| VerfasserIn |
P. S. Minyuk, V. Y. Borkhodoev, V. Wennrich |
| 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 ; 10, no. 2 ; Nr. 10, no. 2 (2014-03-12), S.467-485 |
| Datensatznummer |
250116933
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| Publikation (Nr.) |
 copernicus.org/cp-10-467-2014.pdf |
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| Zusammenfassung |
| Geochemical analyses were performed on sediments recovered by deep drilling
at Lake El'gygytgyn in central Chukotka, northeastern Russia
(67°30' N; 172°05' E). Major and rare element
concentrations were determined using X-ray fluorescence spectroscopy (XRF) on
the < 250 μm fraction from 617 samples dated to ca. 440 and 125
ka, which approximates marine isotope stages (MIS) 11 to 6. The inorganic
geochemistry indicates significant variations in elemental composition
between glaciations and interglaciations. Interglacial sediments are
characterized by high contents of SiO2, Na2O, CaO, K2O, and Sr
and are depleted in Al2O3, Fe2O3, TiO2, and MgO. An
extreme SiO2 enrichment during MIS 11.3 and 9.3 was caused by an
enhanced flux of biogenic silica (BSi). The geochemical structure of MIS 11
shows similar characteristics as seen in MIS 11 records from Lake Baikal
(southeastern Siberia) and Antarctic ice cores, thereby arguing for the
influence of global forcings on these records. High sediment content of
TiO2, Fe2O3, MgO, Al2O3, LOI, Ni, Cr, and Zr
typifies glacial stages, with the most marked increases during MIS 7.4 and
6.6. Reducing conditions during glacial times are indicated by peaks in the
Fe2O3 content and coinciding low Fe2O3/MnO ratios. This
conclusion also is supported by P2O5 and MnO enrichment, indicating
an increased abundance of authigenic, fine-grained vivianite. Elemental
ratios (CIA, CIW, PIA, and Rb/Sr) indicate that glacial sediments are
depleted in mobile elements, like Na, Ca, K and Sr. This depletion was caused
by changes in the sedimentation regime and thus reflects environmental
changes. |
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