CHARACTERISTICS, ORIGIN AND EVOLUTION AGES OF AEOLIAN SAND IN THE SAHELIAN REGION OF MALI

摘要

The Sahelian region of Mali is one of the areas seriously affected by sandy desertitication in the world. Widely distributed aeolian sand lays a material basis for the development of sandy desertification. Aeolian sand in the Region is dominated by fine sand, followed by very fine sand. Sand materials contained in various sand dunes are differ- Ent in grain size to a certain extent and the mineral compositions of dune sand are dominated by stable and extreme sta- ble minerals, with high stability and maturity. Aeolian sand in the region mainly comes from the reactivation of ancient Sand dunes, the transportation of recent running water and the sand supply of dry lakes and arroyos. Since the Pliocene This region has experienced four major evolution periods of aelian sand, namely from the Pliocene to the early Quarter- Nary, last glacial period, the Holocene and present.