The Development and Characteristics of Sand Seas in the Central Sahara

The central Sahara, although geomorphically diverse, is best known for its sand seas and their component sand dunes. This study describes the geomorphic setting of the different sand seas (ergs) of the central Sahara region, including their distribution, history of development and their principal geomorphic properties. This background then sets the scene for considering the detailed geomorphology, including the dunes, of the Grand Oriental Sand Sea and the Fachi-Bilma Sand Sea (Ténéré Desert), based on the existing literature and new analysis of remote sensing imagery. These results show that the sand seas contain different dune types in different areas, and that these dunes have highly variable properties which suggests they have different evolutionary histories. The outcome of this study is that, unlike its popular conception, Saharan sand seas and sand dunes are not monotonous and uniform, but have highly diverse properties which likely reflect a punctuated evolutionary history, in particular during the Quaternary, as well as different contemporary dynamic behaviours in response to present-day wind regimes.