High-amplitude lake-level changes in tectonically active Lake Issyk-Kul (Kyrgyzstan) revealed by high-resolution seismic reflection data
- 1Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, 27576 Bremerhaven, Germany
- 2Royal Belgian Institute of Natural Sciences, Operational Directorate Natural Environment (RBINS–OD Nature), 8400 Ostend, Belgium
- 3Renard Centre of Marine Geology, Universiteit Gent, 9000 Ghent, Belgium
- 4International Bureau for Environmental Studies (IBES), 1090 Brussels, Belgium
- 5Kyrgyz Institute of Seismology, Bishkek, Kyrgyzstan
- 6Institut für Erd- und Umweltwissenschaften, International Universität Potsdam, 14476 Potsdam, Germany
Abstract. A total of 84 seismic profiles, mainly from the western and eastern deltas of Lake Issyk-Kul, were used to identify lake-level changes. Seven stratigraphic sequences were reconstructed, each containing a series of delta lobes that were formed during former lake-level stillstands or during slow lake-level increase or decrease. The lake level has experienced at least four cycles of stepwise rise and fall of 400 m or more. These fluctuations were mainly caused by past changes in the atmospheric circulation pattern. During periods of low lake levels, the Siberian High was likely to be strong, bringing dry air masses from the Mongolian steppe blocking the midlatitude Westerlies. During periods of high lake levels, the Siberian High must have been weaker or displaced, and the midlatitude Westerlies could bring moister air masses from the Mediterranean and North Atlantic regions.