第七届青年地学论坛

The western Sahara Desert is dominated by aeolian dunes; yet, research on the geomorphology of aeolian dunes throughout this region as a unit has been limited compared with other large deserts in the world. In the present study, comprehensive research is conducted on the geomorphology of dunes in the western Sahara Desert based on satellite images and meteorological data. Then, the controlling factors on the dune morphology and formation of superimposed dunes are identified. The results suggest that the spatial patterns of dune morphology are closely correlated to the drift potential (DP) and dune orientation. A well-defined gradient of declining DP, resultant drift potential, and directional wind variability from north to south was found, indicating a gradual weakening trend in the DP along the sand flow path. Linear and transverse dunes are distributed on the central part of the desert. Barchan dunes are distributed on the western coastal areas and desert margins. Star dunes are distributed in the upwind on the northern desert margin. By combining our results with the sand transport dynamic members and dune mobility index, we determined that the wind regime and sand availability are the key factors in dune formation and geomorphology. Furthermore, the duration of sand transport and accumulation is critical for dune development. Evidence from the dating of dunes and depositional paleoenvironments of marine core sections leads to the conclusion that superimposed dunes are the product of multiple periods of dune construction. However, the surface structures of superimposed dunes are a modern modification of preexisting dunes. The results of this study provide valuable reference data on regional aeolian activities and can be used by subsequent regional aeolian geomorphology studies in the western Sahara Desert.

地貌,沙丘,生长机制,漂移潜力,西撒哈拉沙漠,运输动力学