Sedimentary environments of pre-Acheulian and Acheulian sites of Akerdil and Bamouere wadis (Guelb er-Richat, Adrar, Mauritania), a first approach

In the Mauritanian Adrar, the Guelb er-Richat and, in particular, the depression of its external ring are the location of rather exceptional Acheulian industry accumulations discovered by Theodore Monod. These sites may have originated from one or more non dated humid phases where seasonal water presence induced faunal and thus predator presence. Piedmont relief, foot slope rock flow and deltaic spreads attest, until the last humid Holocene, the permanence of particularly favourable sectors like upstream of Akerdil and Bamouere wadis. Outcrops or chaos of Chinguetti quartzite sandstone have supplied the necessary raw material for tool confection; the second factor favouring the presence of these Acheulian sites. The rather difficult aim of the authors is first, to locate lithics in stratigraphic position and second, to establish a chronostratigraphy. Some first examples are presented. All rights reserved, Elsevier