Réponse des environnements aux climats du début glaciaire weichsélien : données de la France du Nord-Ouest [ Responses of the environments to Early Weichselian climates. Records in northwestern France. ]

The morphological, palynological and pedosedimentary data from North-western France indicate step-wise evolution during Early Weichselian. These changes occurred especially at the end of the eemian interglacial and after the Brorup and Odderade interstadials. The tendency to a continental climate was marked as early as the Brorup when the sea level was lowered more than 20 meters. On the other hand during the Brorup and Odderade interstadials, a morphogenic equilibrium persisted. During the last phasis of the Early Glacial, the continentalisation increased, conducting to disparition of the forest. It is important to observe that the apparition of penglacial phenomena is clearly subsequent to the soil complex, justifying the attribution of this pedostratigraphic unit to the Early Glacial. This graded change towards cooling and especially draught is recorded among deposits and soils of the Soil Complex of Saint-Sauflieu (Somme) which is the type-profile of Early Glacial humiferous soils.