Continental palaeoenvironments during MIS 2 and 3 in southwestern France: the La Ferrassie rockshelter record

Reappraisal of La Ferrassie rockshelter sequence provides novel information on the continental palaeoenvironments in southwestern France during the end of Marine Isotope Stage 3 and the beginning of MIS 2. Cycles of sedimentation and soil development have been recognised, and are tentatively interpreted as reflecting the Dansgaard/Oeschger climatic cycles. From bottom to top, the sequence shows a trend to progressive reduction in length (and/or intensity) of the soil-forming periods and conversely, an increase in frost-related processes and sedimentation. Cambisols, associated with significant clay weathering and decalcification, developed at the base of the sequence (≥35 to ∼30 14C kyr BP). They are then replaced by simple carbonate-rich humus horizons during the interval ∼30 to ∼28 14C kyr BP. At the beginning of MIS 2, the talus dynamics shifts from rockfall accumulation with intense snow-induced washing to stone-banked solifluction lobes in connection to a semi-desert-like periglacial environment.