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| Titel |
Climate in continental interior Asia during the longest interglacial of the past 500 000 years: the new MIS 11 records from Lake Baikal, SE Siberia |
| VerfasserIn |
A. A. Prokopenko, E. V. Bezrukova, G. K. Khursevich, E. P. Solotchina, M. I. Kuzmin, P. E. Tarasov |
| 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 ; 6, no. 1 ; Nr. 6, no. 1 (2010-01-20), S.31-48 |
| Datensatznummer |
250003323
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| Publikation (Nr.) |
 copernicus.org/cp-6-31-2010.pdf |
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| Zusammenfassung |
A synthesis of paleoclimate responses from Lake Baikal during the MIS 11
interglacial is presented based on proxy records from two drill sites 245 km
apart. BDP-99 is located in vicinity of the delta of the major Baikal
tributary, whereas the BDP-96 site represents hemipelagic setting distant
from riverine influence. The comparison of thicknesses of interglacial
intervals in these contrasting depositional settings confirms the extended
ca. 33-kyr duration of the MIS 11 interglacial. The new BDP-99 diatom
biostratigraphic record matches that of the BDP-96-2 holostratotype and thus
allows establishing establishes robust correlation between the records on
the same orbitally-tuned timescale.
The first detailed MIS 11 palynological record from the BDP-99 drill core
indicates the dominance of boreal conifer (taiga) forest vegetation in the
Baikal region throughout the MIS 11 interglacial, since at least 424 ka till
ca. 396 ka. The interval ca. 420–405 ka stands out as a "conifer
optimum" with abundant Abies sibirica, indicative of climate significantly
warmer and less continental than today. The closest Baikal analog to this type of vegetation
in the history of the current Holocene interglacial is at ca. 9–7 ka. The
warm conifer phase lasted for ca. 15 kyr during MIS 11 interrupted by two
millennial-scale cooling episodes at ca. 411–410 and 405–404 ka.
Reconstructed annual precipitation of 450–550 mm/yr during the MIS 11
interglacial is by ca. 100 mm higher than during the Holocene; regional
climate was less continental with warmer mean temperatures both in summer
and in winter.
At both drill sites, the two-peak structure of the MIS 11 diatom abundance
profiles reflects the orbital signature of precession in the interglacial
paleoclimate record of continental Eurasia. MIS 11 interglacial was
characterized by the sustained high level of primary production and
accumulation of autochthonous organic matter at both study sites. The
responses of paleoclimate-sensitive indices in the mineralogy of the MIS 11
sediments in BDP-96-2 are consistent with those during the Holocene.
Illitization of secondary clay minerals in the Baikal watershed was an
important process, but it appears to have been subdued during the first half
of the MIS 11, apparently due to elevated humidity and muted seasonality of
regional climate. |
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