But if the Tassilian landscape owes its appearance to ancient volcanism, in many other regions of the Sahara it is from the complex and obstinate play of a thousand-year-old erosion that the landscape derives its grandiose cut. Not far from the Amojjiar pass, in central Mauritania, one can admire the monumental sedimentary section brought to life by a runoff which, although very rare today, must have been in ancient times of singular power. Sometimes, this enormous work of clearing was carried out in a very short time. In the Immidir, in the Tassilian region, the pottery made by Neolithic man, 3500 years BC, lies under I7 metres of alluvium! - The Saharan landscape is therefore being permanently modified, but this transformation is being singularly slowed down by the current extreme drought. - Mauritania - 1968
