Two opposit conceptions were propounded about climatic variations from northern to southern Sahara during the Quaternary, namely the "climatic balancing movement" and the "contraction of desertic area". Along a N S belt of land, out of high mountains, littoral zones and areas affected by recent tectonic, the absolute datations point out synchronism of climatic variations from southern Maghreb's limit to the sweep of Niger, during the 40 last millenaries.

No abstract

No abstract

This note summarizes the research followed for nearly 15 years on the Quaternary of the Northwest Sahara. Stratigraphically it is possible to characterize the Villafranchian, with two pluvial-arid cycles (Aïdien and Mazzérien) ; the middle Quaternary, with two cycles (Taourirtien and Ougartien) ; and the late Quaternary, with a main cycle (Saourien) followed by a secondary cycle (Guirien). The sedimentary petrography has shown climatic indications in successive deposits (granulometry of pebbles and sands, various marks on pebbles, colorimetry of sands) and some chronological and paleogeographical indications (heavy minerals). Palynological studies in progress reveal the presence, at different times of the Quaternary, of Mediterranean and even temperate trees, associated with herbs of the Saharian steppe. The collections of all the Saharan prehistoric industries, in place in all Quaternary levels, is a useful element in dating. The Pebble Culture appears in the Mazzerien and the beginning of the Taourirtien. The Chelleen and the Acheuleen develop during the Taourirtien, and the Ougartien appears in a series oj stages stratigraphically well defined. Aterien is present toward the base of the sourien deposits, and the Neolithic occurs in the Guirien. A radiocarbon analysis of 20,000 ± 1000 years B.P. dates a saourien level near the Aterien, and one of 6160 ± 320 dates the maximum of the Guirien sedimentation, of Neolithic age.

No abstract