Response of aeolian systems to Holocene climatic and hydrologic changes on the northern margin of the Sahara: a high-resolution record from the Chott Rharsa basin, Tunisia.

Four millennial-scale latest Pleistocene to Holocene climatic cycles are recorded by aeolian-lacustrine strata along the southern margin of Chott Rharsa, a playa situated within an active tectonic basin along the northern margin of the Sahara Desert in Tunisia. Cycles are characterized by (1) a humid phase of dunefield stabilization and high lake levels, and (2) an arid phase of playa desiccation and deflation with dunefield construction. The cycles overall define a progressive drying trend and correlate well with a detailed chronology from Morocco and with the Sahara region in general for the latest Pleistocene and early Holocene. Climatic events appear more regional in nature for the later Holocene. An isolated outcrop of aeolian deposits dated at .86 ka BP argues for records of older cycles in the Chott Rharsa Basin that were subsequently removed by long-term deflation in the area. [ABSTRACT FROM AUTHOR]