Lake Elgygytgyn in the north-eastern Russian Arctic became the target of extensive international site surveys in the late 1990s, with complex geoscientific fieldwork conducted in 1998, 2000, and 2003. The surveys strongly supported the hypothesis that the lake hosts a nearly continuous sediment record, which is highly sensitive to climatic and environmental changes and covers the time since the lake formation by a meteorite impact some 3.6 Ma ago. These promising findings led to deep drilling operations within the scope of the International Continental Scientific Drilling Program (ICDP) in 2008 and 2009, during which 141 m of permafrost deposits in the catchment, the 318 m thick lake sediment succession in the lake centre, and about 200 m of impact rocks underneath were drilled. Palaeoenvironmental and palaeoclimatological research on the Quaternary part of the lake sediment record revealed that full glacial conditions, with mean annual air temperatures at least 3.3 ±0.9 °C lower than today, first commenced at the Pliocene/ Pleistocene boundary 2.6 Ma ago. They gradually increased in frequency from ca. 2.3 to 1.8 Ma, eventually concurring with all global glacials and several stadials. The interglacials at Lake Elgygytgyn significantly differ in intensity. So-called super interglacials irregularly occurred throughout the Quaternary, including Marine Isotope Stages 11.3 and 31, when mean temperatures of the warmest month and annual precipitation were up to 4-5 °C and ~300 mm higher than today, respectively. According to climate modelling these climatic settings cannot in all cases be traced back to orbital forcing or greenhouse gas concentrations. They are, at least partly, the result of other processes and feedbacks in the climate system. A remarkable coincidence of the super interglacials with diatomite layers in the Antarctic ANDRILL 1B record suggests that they were associated with considerable retreats of the West Antarctic Ice Sheet. The ice decay may have caused reductions in Antarctic Bottom Water formation, its transport to the Pacific Ocean, and its upwelling in the north-western Pacific, and potentially increased warm-water intrusions through the Bering Strait into the Arctic Ocean.
Bibliographical noteFunding Information:
The drilling operation at Lake El’gygytgyn was financed by the International Continental Scientific Drilling Program (ICDP), the US National Science Foundation (NSF), the German Federal Ministry of Education and Research (BMBF), Alfred Wegener Institute (AWI) and GeoForschungsZentrum (GFZ), the Russian Academy of Sciences Far East Branch (RAS FEB) and Russian Foundation for Basic Research (RFBR), and the Austrian Federal Ministry of Science and Research (BMWF).
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- Lake Elgygytgyn
- Super interglacials
Continental Scientific Drilling Facility tags