Interactions between paleochannels and aeolian processes and their implications on aeolian dune patterns

Abstract

Despite paleochannels play a key role in the evolution of aeolian dune patterns, little attention has been paid on the interactions between paleochannels and aeolian processes. The objective of this article is to analyze the interactions between paleochannels and aeolian processes and their implications on the aeolian dune patterns. One site in the Kuruk Tagh Desert in eastern margin of the Tarim Basin, northwestern China is selected as the case study area. We analyze the sedimentary environment of the aeolian dunes around paleochannels based on the grain-size parameters. Furthermore, we present spatial and temporal dynamics of the vegetation and aeolian dunes around the paleochannels. The results indicate that: (1) ground water determines the spatial distribution of the vegetation and controls the evolution of aeolian dune patterns indirectly; (2) aeolian dunes around the paleochannels are initially controlled by fluvial and aeolian processes collectively. Then, the aeolian processes always play a dominant role after the drying up of these paleochannels; (3) the paleochannels in aeolian processes dominated areas ultimately evolve into a belt sand source due to the deposition of aeolian sediments and the encroachment of aeolian dunes. The timescale of the paleochannels’vanishment depends not only on the depth and width of the channels, but also on the angle between bedform orientation and prevailing sand flux direction.