A new chronology of upper Holocene aeolian sands in the Zibans range, Algeria

Abstract

The existence of a transatlantic aeolian system through the eastern Saharan Atlas points out massive migrations of mobile sands from the High Plains in the North to the Sahara Desert in the South and confirms that in Algeria, there is not a progression of desertification from the Sahara toward the North. The age of these sand displacements is ancient and dates back to the Upper Pleistocene and the Holocene. A new chronology of Upper Holocene, supported by 12 new 14C datings, indicates variations of arid periods and humid periods. This new chronology characterizes an evolution stage since 4000 BP marked by the rapidity of paleoenvironmental instabilities during the Upper Holocene period through the Zibans range with the development of four sequences: a humid phase during 3300-3000 14C yr BP; an arid phase during 2900-2500 14C yr BP; a humid phase during 2400-2200 14C yr BP; an arid period between 2200 and 1650 14C yr BP dominated by incision of rivers where man's role became more and more important. The present-day remobilization of sands doesn't justify an aridification of the climate.