Paleolimnological investigations of selected lakes along a north-south transect from the Lena delta (Laptev Sea region) to its hinterland

• Main Authors: Biskaborn, Boris, Funk, Christiane, Herzschuh, Ulrike, Bolshiyanov, D., Vakhrameeva, P., Subetto, D., Diekmann, Bernhard
• Format: Conference Object
• Language: unknown
• Published: 2010
• Subjects: Arctic; Arga; Laptev Sea; laptev; lena delta; Thermokarst; Siberia
• Online Access: https://epic.awi.de/id/eprint/23578/; https://hdl.handle.net/10013/epic.36469

In 2009 a collaborative German-Russian expedition realised an ecological and limnogeological survey along a north-south transect in arctic Siberia. The field studies included 14 thermokarst lake-sites reaching from the Arga region at 73° N within the Lena delta (Laptev Sea regioin) to the Lena hinterland at 69° N crossing the treeline. Based on the findings of this pre-survey (e.g. significant high sedimentation rates) a follow-up expedition in 2010 was undertaken to continue the paleolimnological studies at Lake El'gene Kyuele (71°18,04' N, 125°34,15' E) in the middle part of the transect and Lake Kyutyunda (69°37,89' N, 123°39,42' E) near the southernmost position of the transect. During this expedition longer sediment cores up to 8 m could be retrieved using an Uwitec piston corer system from a platform. Additionally the catchment area and the lake bathymetry were analysed.El'gene Kyuele has a length of 2.9 km and a width of 0.5 km. The lake bottom shows a strong relief with a maximum water depth of 10.5 m. The small catchment area reveals intensive thermokarst processes of the surrounded deeply loesslike sediments (Yedoma). The elongated shape corresponding to the regional geological structure of the bedrock also indicates a tectonic component influencing the thermokarst lake genesis.We intend to compare the sedimentological and paleoenvironmental regimes of 4 selected lakes of the transect in order to gain informations about temporal environmental changes in the gradient from the north to the south. Our main questions are: How much is the thermokarst erosion influencing the sedimentological regime? Is the lake bathymetry only controlled by thermokarst subsidence processes? Is there a paleoclimate signal triggering the detrital input events? To answer this questions bio-geochemical, geochemical and grain-size studies were conducted on several sediment cores along the selected lakes of the transect.The aim of the research project is to understand and reconstruct the sedimentary thermokarst processes and the Holocene palaeoenvironmental gradients reaching from the southern extrem continental settings to the Laptev-Sea region.