| Summary: | An archaeological survey carried out at Saint-Vincent-de-Paul, about 11 km northeast of Dax (Landes, southwest France) made it possible to investigate a new sequence of aeolian sands overlying a Middle Pleistocene alluvial terrace of the Adour River. A peat level with wood fragments was found between 2.2 and 2.4 m depth at the bottom of a gully incised in, and then filled with aeolian sands. The peat, 14C dated on wood fragments to 26,731 ± 101 BP (31,136-30,844 cal BP) and 28,066 ± 106 BP (32,821-31,655 cal BP), can be correlated with the interstadial GI-5.1 (or possibly GI-5.2) of the Greenland Ice Core Chronology, i.e., in the latter part of Marine Isotope Stage (MIS) 3. The scarcity of Pleistocene peats in the region makes this discovery highly valuable for documenting the palaeoenvironments contemporary with the Middle Gravettian. The peat was cross-studied for pollen, non-pollen palynomorphs (NPPs), charred particles and woody macroremains. At the beginning of peat formation, a reed bed associated with willows developed locally in a treeless landscape. The surrounding area was covered by steppe vegetation, dominated by sagebrush. Later, the gully was colonized by birch trees, accompanied by Salix, Myrica, Calluna and Erica cf. tetralix. Finally, a sphagnum bog colonized by Myrica, Calluna and Erica cf. tetralix developed. The phase of woodland growth was synchronous with an increase in charred particles. This study together with the previous analyses made on regional MIS 3 peats strongly suggests that patches of boreal forest repeatedly developed in favorable locations in the Landes region during the interstadials of the Last Glacial and lends support to the assumption of discontinuous aeolian activity in the coversand area. Des sondages archéologiques réalisés à Saint-Vincent-de-Paul, à environ 11 km au nord-est de Dax (Landes, sud-ouest de la France) ont permis d’étudier une nouvelle séquence de sables éoliens recouvrant une terrasse alluviale de l’Adour attribuée au Pléistocène moyen. Un niveau de ...
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