Late Quaternary landscape dynamics of nonglaciated Arctic Siberia Results from eight years of studying the Laptev Sea coastal lowlands

• Main Authors: Schirrmeister, Lutz, Hubberten, Hans-Wolfgang, Andreev, Andrei, Grosse, Guido, Kienast, Frank, Meyer, Hanno, Siegert, Christine, Schwamborn, Georg, Kunitsky, V., Kuznetsova, T., Derevyagin, Alexander Yu, Kuzmina, S.
• Format: Conference Object
• Language: unknown
• Published: 2006
• Subjects: Arctic; East Siberian Sea; Ice; laptev; Laptev Sea; lena delta; New Siberian Islands; permafrost; wedge*; Yakutia; Siberia
• Online Access: https://epic.awi.de/id/eprint/16594/; https://hdl.handle.net/10013/epic.26458

Numerous coastal exposures and drill cores of permafrost deposits have been studied in the coastal lowlands surrounding the Laptev Sea to the East Siberian Sea since 1998 within the frame of the Russian-German Science Cooperation SYSTEM LAPTEV SEA. Geochronological, palaeoecological, sedimentological, and geocryological studies permit the reconstruction of palaeoenvironment dynamics of these nonglaciated Arctic lowlands in Yakutia. Permafrost aggradation and degradation, triggered by Quaternary climate changes, are the most important regional processes characterizing the landscape evolution. Composite sequences are presented illustrating the various palaeoenvironmental stages within the last 200,000 years. Both, sharp sedimentary discontinuities probably caused by seismotectonic events, and long-term, gradual transitions in accumulation conditions were discovered. In addition, there are clear differences in local stratigraphy between the eastern part of the Laptev Sea region (New Siberian Islands and the Dimitrii Laptev Strait) and the western Laptev Sea area (Lena Delta; Lena-Anabar lowland).The presentation will summarize our new palaeoenvironmental results and stratigraphic conclusions starting from Late Saalian (Tazovsky) Ice Complex deposits on Bolshoy Lyakhovsky Island, the reconstruction of records from Eemian (Kazantsevo) ice wedge casts, and Early Weichselian (Zyryansky) floodplain deposits there. In the western Laptev Sea region, the visible permafrost sequences started later beginning with Early Weichselian (Zyryansky) fluvial deposits that reflect extended fluvial runoff in front of the main mountain chains (the Kharaulakh, the Chekanovsky and the Pronchshishev Ridges) between 100 to 60 ky BP.The onset of the widely distributed Yedoma sequences varies between 80 and 28 ky BP at various locations. Nevertheless, there were generally similar accumulation conditions for these ice-rich permafrost deposits with huge ice wedge growth in flat and poorly drained lowland plains. Whereas Yedoma sequences are ...