Geomorphological evolution of Mediterranean enclosed depressions in the Late glacial and Holocene: The example of Canohès (Roussillon, SE France)

Abstract

The origin and evolution of the enclosed depressions (pans) of southern France during the period from the Late Glacial to the Holocene are discussed on the basis of new stratigraphical, geophysical and chronological (14C) data from the Canohès depression (Roussillon, Southern of France) and its nearby environment. The Canohès depression is non-karstic, excavated from Pliocene arkosic sands that were shaped by eolian erosion during cold stages of the Middle and Upper Pleistocene. The timing and controlling factors of eolian carving of the depression are discussed on the basis of geomorphological data, surrounding alluvial terrace chronology, preserved ledge within the depression and alluvial infill of the depression.Formation of the depression was controlled, locally, by climate variability and its consequences on vegetation and water table position and, regionally, by the sea base level. The enclosed depression probably started to form during MIS 6, reaching its maximum depth during MIS 2. Climate variability in the region is recorded in the depression's infill. The basal deposits are of fluvial origin and record the increase of moisture and temperature during the Early Late-Glacial. The first lacustrine deposits are observed during the Bölling/GI-1e stage, while continental sedimentation and drying occurred during the Alleröd and Younger Dryas stages. During the Early and Middle Holocene, lacustrine conditions prevailed, except during short periods of drying. The specific evolution of the Canohès depression as regards other such formations is discussed in light of regional deglaciation and climate chronology. A regional synthesis of eolian erosion is proposed.