Dmitrii Zastrozhnov, Andrey Zastrozhnov, Sergei Medvedev, Idris Idrisov, Viktor Spiridonov, Dmitry Nazarov

The highest aeolian landform in Europe, the Sarykum dune complex, is located in the southwestern Caspian Depression near the Caucasus Mountains. Despite its prominence and accessibility, its morphology and evolution have been previously poorly understood. In this study we investigate the dune complex through a synthesis of geomorphological, geological, and geochronological methods. Our findings link its development to climatic aridification driven major regression phases of the Caspian Sea during the Late Pleistocene–Holocene. Optical stimulated luminescence dating indicates that dune formation began at least 70 ka during the Atelian regression, with reactivation around 12–8 ka during the Mangyshlak regression. By the early Holocene, the complex had nearly reached its modern height. The Shura-Ozen’ River, which divides the dune complex in two major segments, played a significant role in the complex’s evolution, influencing aeolian sediment transport and trapping material on its banks, particularly on the left bank, where the highest Central Massif is located. Extensive vegetation now stabilizes most of the complex, except for active ridges in the Central Massif. A numerical analysis of wind potential for dune migration, based on meteorological data spanning the past 55 years, shows that sand movement is primarily driven by self-sustaining NW–SE wind fluctuations. Paleowind analysis suggests that similar long-term wind patterns have persisted since the onset of aeolian deposition during the Atelian phase. Our multidisciplinary study sheds new light on the Sarykum dune complex's history and highlights its significance as a dynamic archive of climatic and geomorphic processes in the Caspian region.