Helena Alexanderson
Professor
Ice-dammed lakes and rerouting of the drainage of northern Eurasia during the Last Glaciation
Author
Summary, in English
During the Quaternary period, ice sheets centred over the Barents and Kara seas expanded several times onto mainland Russia and blocked northflowing rivers, such as the Yenissei, Ob, Pechora and Mezen. Large ice-dammed lakes with reversed outlets, e.g. toward the Caspian Sea, formed south of these ice sheets. Some lakes are reconstructed from shorelines and lacustrine sediments, others mainly from ice-sheet configuration. Ice-dammed lakes, considerably larger than any lake on Earth today, are reconstructed for the periods 90-80 and 60-50 ka. The ages are based on numerous optically stimulated luminescence (OSL) dates. During the global Last Glacial Maximum (LGM, about 20 ka) the Barents-Kara Ice Sheet was too small to block these eastern rivers, although in contrast to the 90-80 and 60-50 ka maxima, the Scandinavian Ice Sheet grew large enough to divert rivers and meltwater across the drainage divide from the Baltic Basin to the River Volga, and that way to the Caspian Sea. Climate modelling shows that the lakes caused lower summer temperatures on the continent and on the lower parts of the ice sheet. The final drainage of the best mapped lake is modelled, and it is concluded that it probably emptied within few months. We predict that this catastrophic outburst had considerable impact on sea-ice formation in the Arctic Ocean and on the climate of a much larger area. (C) 2003 Elsevier Ltd. All rights reserved.
Department/s
- Quaternary Sciences
Publishing year
2004
Language
English
Pages
1313-1332
Publication/Series
Quaternary Science Reviews
Volume
23
Issue
11-13
Links
Document type
Journal article
Publisher
Elsevier
Topic
- Geology
Status
Published
ISBN/ISSN/Other
- ISSN: 0277-3791