Forms and deposits of the continental quaternary of the Saharan margin of Eastern Maghreb (tentative synthesis)

Abstract

The Saharan margin of Eastern Maghreb extends from Aurès in the West to the Gulf of Gabès in the East. The Plio-Quaternary boundary is very complex in the West where it is characterized by the persistence of Tertiary sedimentation with the development of ablation forms, presence of crusts and the formation of a lacustrine system. This is followed by the development of accumulation forms during the Middle Pleistocene and mostly during the Upper Pleistocene to Holocene with contemporaneous diminution in the granulometry of the deposits. The evolution of gypcretes at the expense of calcretes crust suffered a partial reverse during the Middle Pleistocene. At this time a lacustrine phase settled down in the Algero-Tunisian Chotts (sebkhas). The end of the Middle-Pleistocene corresponded with a major climatic break with the disappearance of the calcretes. By the end of the Upper Pleistocene, the gypcretes attained their maximum development and latter disappeared during the Holocene.