Chapter

Land-Ocean Systems in the Siberian Arctic

pp 657-665

Late Pleistocene Paleoriver Channels on the Laptev Sea Shelf - Implications from Sub-Bottom Profiling

  • H. P. KleiberAffiliated withAlfred-Wegener-Institut für Polar- und Meeresforschung
  • , F. NiessenAffiliated withAlfred-Wegener-Institut für Polar- und Meeresforschung

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Abstract

Bottom and sub-bottom reflection patterns received by the PARASOUND system (4 kHz) document 24 filled paleoriver channels in the uppermost sediments (l–13m) of the Laptev Sea shelf. The surfaces of the paleochannel fillings range from 32 to 97 m below the present sea level. The rivers are supposed to have been active during Weichselian time when the sea level was up to 120 m below that of today. They were probably filled during termination 1 until the transgression reached the present-day 30 m-isobath. The observed paleoriver channels are most likely related to the Olenek, Lena and Jana rivers and to local drainage systems on the Taymyr Peninsula and the New Siberian Islands. In the depth range of 2 to 20 m sub-bottom, a strong post-sedimentary reflector is commonly found, interpreted as the surface of submarine permafrost. The formation of paleoriver channels and permafrost is associated with subaerial exposure and suggest that most of the Laptev Sea shelf area was not covered by a large ice sheet during the last glacial maximum.