Lower North Sahara & Great Eastern Erg

Bas Sahara septentrional & Grand Erg Oriental

Jean-Louis Ballais (1, 2) , Abdelkader Heddouche (3)

1 CAGEP - Centre Aixois de Géographie Physique
2 Université de la Méditerranée - Aix-Marseille 2
3 Musée du Bardo, Alger

Compiling of bibliographic data has been completed with unpublished data and personal field research. They tend towards the evidence that Upper Pleistocene climatic fluctuations in Lower Sahara are contemporary with the temperate Europe ones and having the same characteristics. For example, during Eemian interglacial, lacustrine phases occured in the Grands Chotts tunisiens at 150 - 140,000 years B.P. and at 90 - 85,000 years B.P. (230 Th/243U). At the same times, Douira then/or Rejiche marine transgressions occured in the Gabès gulf. Acheulean might disappeared during this phase. The second part of Upper Pleistocene began with a probably very arid phase, more arid than at the present time (from 80,000 years B.P. to about 35,000 years B.P.). During this phase, the first generation of eolian sands deposits in Gafsa region and Matmata plateau was accumulating, blown by North winds. At the same time, the second Great Eastern Erg eolian sands generation accumulated too. The lack of precise datings on classical Mousterian sites as El-Guettar and oued el Akarit preclude all interpretation of associated faula and floral fossil remains. From about 35,000 years B.P. to about 23,000 years B.P., climate became wetter. It allowed the genesis of glacis 2, the accumulation of terrace 2 and the development of pedogenesis in the previous eolian deposits (in Gafsa region, Great Eastern Erg, Ziban range and Matmata plateau). A marine transgression took place at this moment. Pleniglacial (22 - 14,000 years B.P.) is very arid, more arid than at the present time. Again, deflation dug into The Grands Chotts tunisiens. Then eolian sands accumulated (Gafsa and Bir Oum Ali region, Matmata plateau, El-Haouita, Bou Saada, Great Eastern Erg third generation) even on the seaside (Tlêt formation) where a main marine regression occured. Bladelets industries makers settled down in some of these eolian accumulations. During Late Glacial (14 - 10,000 years b.P.), temperate Europe type climatic fluctuations very probably occured. Bladelets industries persist up to about 10,000 years B.P. while first Capsian industries are appearing.

La compilation des données bibliographiques complétée par des données inédites et des observations de terrain tend à prouver que les fluctuations climatiques du Pléistocène supérieur dans le Bas-Sahara ont été contemporaines de celles d'Europe tempérée et de même sens (de froid et sec à chaud et plus humide). Cependant, la période d'environ 80 000 ans B.P. à environ 35 000 ans B.P. reste très mal connue, en l'absence de datations autres que relatives. De plus, les données concernant le Paléolithique et l'Epipaléolithique ne permettent qu'un bref aperçu sur l'occupation humaine de cette région. La nécessité de nouvelles fouilles, y compris dans des sites classiques, est affirmée.

Mots clés: Variations climatiques; Paléolithique; industries à lamelles; Capsien; dépôts éoliens; glacis

Domaines: Sciences de l'environnement; Sciences de l'Homme et Société

Jean-Louis Ballais, Abdelkader Heddouche. Bas Sahara septentrional & Grand Erg Oriental. Thierry Tillet. Sahara. Paléomilieux et Peuplement Préhistorique au Pléistocène supérieur, L'Harmattan, pp.139-163, 1997, 2-7384-6086-0. ⟨hal-01567846⟩