SibLake - Eastern Siberian Lakes
AWI, BMBF, DFG
- Prof. Dr. Luidmilla Pestryakova, Northeast Federal University, Yakutsk, Russia.
- Prof. Dr. Dmitry Subetto, Karelian Research Centre of RAS, Petrozavodsk, Russia.
- Dr. Oleg Dirksen, Institute of Volcanology and Seismology, Petropavlovsk, Russia.
- Dr. Veronika Dirksen, Institute of Volcanology and Seismology, Petropavlovsk, Russia.
- Dr. Ulrike Hoff, Department of Geology, University of Tromsø, Norway.
- Prof. Dr. Pavel Tarasov, Institute of Geological Sciences, Free University Berlin, Germany.
- Prof. Dr. Ulrike Herzschuh, Dr. Hanno Meyer, AWI Potsdam
The availibility of terrestrial records of Holocene palaeoenvironmental changes in eastern Siberia is quite limited. Compared to other places on the northern hemisphere, this climate-sensitive region is very underrepresented. Situated at the border of northeastern Eurasia, it offers the potential to pinpoint connections of Arctic to sub-Arctic palaeoenvironmental changes between the periglacial and highly continental landmasses of Yakutia and the maritime-influenced setting of Kamchatka. In order to widen our understanding of palaeoclimate dynamics in eastern Siberia, sediment records from different lake systems were studied on north-south and west-east transects during the last decade. The studies followed a multi-proxy approach, using sedimentological and geochemical data as well as fossil bioindicators, such as diatoms, pollen and chironomids. Chronostratigraphy of the studied records was achieved through radiocarbon dating and tephrostratigraphy.
The possibly oldest lakes of Yakutia were formed in proglacial settings in the Verkhoyansk Mountains and the Stanovoy Mountains foreland during the mid-Weichselian ice age. As in other worldwide regions, this time was punctuated by warmer interstadials at millennial time scales, as documented by short-term changes in hydrological lake status and surrounding vegetation. The last glacial maximum was characterized by dry conditions and low lake level. High-resolution records of Holocene climate variability are preserved in lakes on Kamchatka Peninsula and are included in the widespread thermokarst lakes of the Yakutian lowlands. They document a regional climate optimum between 7.0 and 4.5 ka BP. Superimposed on the long-term climatic trend are short-term climate punctuations and cyclic changes in lake level at centennial time scales, which demonstrate a high impact of internal climate variability on the palaeoenvironment, likely related to atmospheric oscillation patterns. Many of the thermokarst lakes, however, reveal changes in the lacustrine depositional environment that were driven by permafrost dynamics, only mediately related to climate changes.