Aeolian and fluviolacustrine landforms and prehistoric humanoccupation on a technically influenced floodplain margin, the Méma, central Mali

Abstract

The Mema is a semi-arid region in central Mali with a rich archaeologicalheritage indicating the former existence of large urban settlements. Thearchaeological data suggest millennia of occupation history of the Mémapreceding relatively sudden abandonment by the 14th or 15th century AD.Population numbers have remained low since then and today’s human presencein the area is sparse and largely mobile. Geomorphologically, the Méma canbe characterized as a graben hosting various generations of aeolianlandforms and (presently mostly dry) interdunal channels and lakes, linkedto the neighbouring Inland Niger Delta floodplain. Given this setting, andthe variability of the Sahelian climate, climatic contributions to theregion’s sudden abandonment are likely. A geomorphological survey of theregion, and interpretation of the observed geomorphological record in termsof climatic history, aimed at providing a basis for understanding theintensive occupation and subsequent abandonment of the Méma. The results ofthis study underscore dramatic Holocene climatic variability, leading to theregion’s present geomorphological diversity, but also suggest thatneotectonic movements constitute an important additional cause of regionaldesiccation. Both may have encouraged prehistoric people to abandon the Mémaafter a long period of occupation.