Aeolian-alluvial interactions at Formentera (Balearic Islands, Western Mediterranean): The late Pleistocence evolution of a costal system

This study deals with the sedimentological and stratigraphic description of Pleistocene coastal deposits of Formentera Island that show evidence of interference between processes characteristic of alluvial and aeolian environments. Here we analyze the sedimentology and stratigraphy of a Pleistocene succession located at Northeast of Formentera and we constrain its chronology by optically stimulated luminescence (OSL) dating. Main sedimentary facies representing the succession of aeolian, alluvial, marine and coastal environments are described in this study. We conclude that although there were two prevailing environments such as coastal aeolian and alluvial, with different processes and resulting forms, the interaction resulted in deposits that share characteristics of both environments, as well as maintain elements inherited from each environment in terms of sedimentary supply, precipitation, runoff or aeolian transport. These coastal deposits represent a small alluvial apron covering the base of a vertical cliff. Most of the sediment that composes these deposits is marine bioclastic sand which was transported in the form of coastal dunes during periods of low sea level. Our results are a useful indicator of the geomorphological processes and changes that occurred during the Pleistocene, unraveling the environmental evolution and contributing to the growing knowledge on the Western Mediterranean aeolianalluvial interacting environments.