Variabilité climatique rapide lors du dernier Interglaciaire (stade isotopique marin 5e), enregistrée dans les sédiments littoraux du Sud-Est tunisien

Abstract

We have compared the sedimentological record of the Pleistocene coastal deposits in southeastern Tunisia with the climatic data obtained on two deep-sea cores recovered in the Mediterranean Sea. Coastal marine deposits are composed of two distinct lithostratigraphic units separated by an erosion surface. The radiochemical dating shows that these two units were developed during the unique marine isotopic substage 5e (the Last Interglacial). The lower unit mainly consists of quartz-rich sands whereas the upper one consists of carbonate deposits. This petrographic contrast indicates that the palaeoclimatic evolution in the southeastern coast of Tunisia was identical to that observed in the western Mediterranean Sea and the surrounding continents. In particular, the establishment of humid conditions at the beginning of the Last Interglacial was responsible for a supply of terrigenous material and siliciclastic sedimentation along the coastal area of southeastern Tunisia, whereas the regression of these wet conditions during the second half of the Last Interglacial favoured carbonate sedimentation.