Quaternary glaciations in Southern Africa? A “moraine” in the Lesotho highland revisited

Abstract

Climate records for the Last Glacial Maximum (LGM) in Southern Africa are scarce, and the glaciation of the highest summits has been controversially discussed. Geomorphological features on south-facing slopes at six sites in the high Drakensberg Escarpment of Eastern Lesotho were postulated as moraines indicating marginally short-lived and site-specific glaciation during the LGM. However, previous discussions on precipitation amounts limiting or inhibiting glaciers are challenged by more recent studies suggesting increased humidity and water availability during the LGM. One postulated moraine site at the Tsatsa-La-Mangaung mountain range near Sani Pass was revisited to address the contradictory results. Drone-based remote sensing and field surveys suggest a different formation process of the moraine-like slightly bent landform considering lithological variance and dike system occurrence, which is connected not to glacial but to gravitational and erosional processes. The formation of landforms interpreted as moraines in the high-altitude regions of Lesotho and their paleoclimatic implications for the LGM require reevaluation.