Chapitre 2 : Étude des remplissages tertiaires et quaternaires des dolines du plateau crayeux karstifi é du Long-Buisson à Guichainville / Le Vieil-Évreux (Eure) : chronostratigraphie des niveaux anthropiques

The intensely karsitifi ed chalk plateau of Le Long-Buisson near Évreux, bordering on the Iton Valley, is covered by clay and fl ints, the residues of tertiary sands and partially by recent loess of the Upper Weichselian (post 20 000 B.P.). Depressions associated with the dissolution of chalk (sinkholes of karsitified origin) have ‘played’ on several occasions: during the Lower Pleistocene with a sedimentation of tertiary sands, at the middle of the Middle Pleistocene attested by a combination of leached loess and paleosols (‘red loams’) and, to a lesser extent, during the Lower Weichselian and illustrated by a single example, at the beginning of the deposition of the recent loess during the Upper Weichselian. The anthropic evidence encountered was, either isolated in a disturbed position in the lower loess, or in horizons containing remains close to sinkholes, associated with the lower loess, or in gravels that can be attributed to the last glaciation. The discovery of lithic industries in situ over large areas is of particular interest concerning the site of Le Long-Buisson relative to the analysis of human settlement in the Évreux region and more widely that of Upper Normandy.