Formation of lake dunes in an intramontane basin: A case study from Cuona Lake, on the Qinghai-Tibetan Plateau

Abstract

Although lake dunes are widespread in drylands, their formation, influenced by complex aeolian-fluvial interactions, remains unclear. This study focuses on the dunes around Cuona Lake on the Qinghai-Tibetan Plateau. By combining wind simulation and flow calculation with physical and chemical analyses of the sediments (grain size parameter statistics, elemental composition), we infer the processes of lake dune formation in this semi-arid intramontane basin. Meteorological data were used to resolve the temporal variations in wind and precipitation, and sediment transport pathways were identified from simulations based on wind and topographic data. Grain size and elemental analyses of sediment samples were used to characterize the physical and chemical composition of the Cuona Lake Basin dunes and related sediments. Our results show that dune formation in the Cuona Lake Basin occurs under the alternating control of wind and water processes. Dunes form mainly from sediment transported from the lake beach by westerly winds in the winter and spring; rivers flowing in the opposite direction (eastward) in the summer transport dune sand back to the lake beach. This process accounts for the recycling of sand in the landscape. This spatiotemporal coupling between hydrodynamic and wind transport pathways provides a continuous sediment supply for dune formation around the lake.