Articles | Volume 13, issue 1
https://doi.org/10.5194/cp-13-73-2017
https://doi.org/10.5194/cp-13-73-2017
Research article
 | 
18 Jan 2017
Research article |  | 18 Jan 2017

High-amplitude lake-level changes in tectonically active Lake Issyk-Kul (Kyrgyzstan) revealed by high-resolution seismic reflection data

Andrea Catalina Gebhardt, Lieven Naudts, Lies De Mol, Jan Klerkx, Kanatbek Abdrakhmatov, Edward R. Sobel, and Marc De Batist

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.

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Short summary
Seismic profiles from the western and eastern deltas of Lake Issyk-Kul were used to identify lake-level changes of up to 400 m. Seven stratigraphic sequences were identified, each containing a series of delta lobes that were formed during former lake-level stillstands. Lake-level fluctuations point to significant changes in the strength and position of the Siberian High and the mid-latitude Westerlies. Their interplay is responsible for the amount of moisture that reaches this area.