Late-Holocene sand invasion and North Atlantic storminess along the Aquitaine Coast, southwest France

Abstract

Holocene forested coastal dunes of different morphology fringe the Atlantic coast of southwest Aquitaine. Infra-red stimulated luminescence (IRSL) dating has been applied to sands from these dunes in the Aquitaine region in order to test the validity of dune-classification theories. The ages obtained from the dunes show three phases of sand invasion and dune development during the late Holocene: 3000-4000 years ago; 900-1300 years ago; 250-550 years ago. The timing of the most recent phase of sand mobilization. as dated by IRSL, is supported by historical maps and records from the fifteenth to the eighteenth centuries AD, showing problems for human settlement in the region and village abandonment due to dune drift. Sand invasion is driven by an increase in frequency of severe storms in the North Atlantic associated with the cooler periods of the ‘Little Ice Age’ and early 'Mediaeval Warm Period'. The dunes emplaced 900-1300 years ago were naturally fixed by a mixed deciduous and maritime pine forest during the latter part of the 'Mediaeval Warm Period'.