Contrasts in the Quaternary of mid‐North America and mid‐Eurasia: notes on Quaternary landscapes of western Siberia
Abstract The West Siberian Plain was formed by marine deposits that extended from the Mediterranean basin to the arctic. Tectonic action later produced a striking series of long straight NE–SW grabens in the southern part of the plain. Pleistocene advance of the Kara ice sheet onto the continent res...
| Published in: | Journal of Quaternary Science |
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| Main Author: | |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Wiley
2005
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| Online Access: | http://dx.doi.org/10.1002/jqs.985 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fjqs.985 https://onlinelibrary.wiley.com/doi/pdf/10.1002/jqs.985 |
| Summary: | Abstract The West Siberian Plain was formed by marine deposits that extended from the Mediterranean basin to the arctic. Tectonic action later produced a striking series of long straight NE–SW grabens in the southern part of the plain. Pleistocene advance of the Kara ice sheet onto the continent resulted in blockage of the Ob and Yenisey rivers to form huge proglacial lakes that drained through these grabens south via the Turgay Pass and the Aral, Caspian, Black and Mediterranean seas to the North Atlantic Ocean, but during the Last Glacial Maximum (late Weichselian, isotope stage 2), the Kara ice sheet did not advance onto the continent in northwestern Siberia. The Altai Mountains, which bound the West Siberian Plain on the south, contained large deep intermontane ice‐dammed lakes, which drained catastrophically when the ice dams broke, forming giant ripples on the basin floors. Pollen studies of glacial lakes indicate that the Lateglacial steppe vegetation and dry climatic conditions continued into the early Holocene as summer insolation maintained high levels. Permafrost development on a drained lake floor in the western Altai Mountains resulted in the formation of groups of small pingos. In North America the growth and wastage of the huge Laurentide ice sheet had an indirect role in the climatic history of western Siberia during the Glacial and Lateglacial periods, after which the climate was more affected directly by insolation changes, whereas in North America in the early Holocene the insolation factor was coupled with the climatic effects of the slow wastage of the ice sheet, and the time of maximum dryness was postponed until the mid‐Holocene. Copyright © 2005 John Wiley & Sons, Ltd. |
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