Coastal Retreat and Sedimentation during the Last 3000 Years. Atlantic Coast of NW Spain

Abstract

During the last glaciation, thick nival and periglacial sediments buried large sectors of the NW coast of Spain. The sediments were mostly eroded by the rising sea level during the Holocene, but in several places they remain, forming sedimentary cliffs. Radiocarbon dates obtained at the topmost layers of these cliffs prove that continental sedimentation was active until very recent times, followed by a retreat of the cliffs. During the first stages of the transgression, the erosion of the cliffs and the changes in the coastal system were controlled by the rising sea-level. Once the sea-level stabilized, the exhumation of inherited landforms, the supply of sediments, and a continuous continental sedimentation became the main factors. The last stages of cliff retreat were almost synchronous with the sedimentation of the upper layers of the deposits.