Coastal permafrost landscape development since the Late Pleistocene in the western Laptev Sea,Siberia |
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| Authors: | MARIA WINTERFELD LUTZ SCHIRRMEISTER MIKHAIL N GRIGORIEV VIKTOR V KUNITSKY ANDREI ANDREEV ANDREW MURRAY PIER PAUL OVERDUIN |
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| Institution: | 1. Alfred Wegener Institute for Polar and Marine Research, Telegrafenberg A43, D‐14473 Potsdam, Germany;2. Melnikov Permafrost Institute, Siberian Branch, Russian Academy of Sciences, 677010, Yakutsk, Russia;3. University of Cologne, Institute of Geology and Mineralogy, Zuelpicher Strasse 49a, D‐50674 Cologne, Germany;4. Nordic Laboratory for Luminescence Dating, Department of Earth Sciences, University of Aarhus, Ris? National Laboratory, DK 4000 Roskilde, Denmark |
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| Abstract: | Winterfeld, M., Schirrmeister, L., Grigoriev, M. N., Kunitsky, V. V., Andreev, A., Murray, A. & Overduin, P. P. 2011: Coastal permafrost landscape development since the Late Pleistocene in the western Laptev Sea, Siberia. Boreas, 10.1111/j.1502‐3885.2011.00203.x. ISSN 0300‐9483. The palaeoenvironmental development of the western Laptev Sea is understood primarily from investigations of exposed cliffs and surface sediment cores from the shelf. In 2005, a core transect was drilled between the Taymyr Peninsula and the Lena Delta, an area that was part of the westernmost region of the non‐glaciated Beringian landmass during the late Quaternary. The transect of five cores, one terrestrial and four marine, taken near Cape Mamontov Klyk reached 12 km offshore and 77 m below sea level. A multiproxy approach combined cryolithological, sedimentological, geochronological (14C‐AMS, OSL on quartz, IR‐OSL on feldspars) and palaeoecological (pollen, diatoms) methods. Our interpretation of the proxies focuses on landscape history and the transition of terrestrial into subsea permafrost. Marine interglacial deposits overlain by relict terrestrial permafrost within the same offshore core were encountered in the western Laptev Sea. Moreover, the marine interglacial deposits lay unexpectedly deep at 64 m below modern sea level 12 km from the current coastline, while no marine deposits were encountered onshore. This implies that the position of the Eemian coastline presumably was similar to today's. The landscape reconstruction suggests Eemian coastal lagoons and thermokarst lakes, followed by Early to Middle Weichselian fluvially dominated terrestrial deposition. During the Late Weichselian, this fluvial landscape was transformed into a poorly drained accumulation plain, characterized by widespread and broad ice‐wedge polygons. Finally, the shelf plain was flooded by the sea during the Holocene, resulting in the inundation and degradation of terrestrial permafrost and its transformation into subsea permafrost. |
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