干旱区生态环境知识资源中心

Physiographically, central southern Africa can be defined as the catchment of the Orange River and its tributaries. It comprises a number of terrain-morphological units which have the potential to contribute towards elucidating late Quaternary environmental change within the region. This paper provides an overview of geomorphic evidence and suggests how geomorphology has contributed to a better understanding of central southern African palaeoenvironments. Secondly, it suggests where geomorphology might focus in future, so as to remain relevant. Central southern Africa's topography varies from the mountains of the Great Escarpment (in both South Africa and Lesotho), through the undulating plains of the central Free State province, to plains and pans in the west, and lowlands with hills in the south. The predominant geology comprises Karoo Supergroup sedimentary rocks, with igneous intrusions and basalts on a sub-regional scale. The region's geomorphology has provided evidence for late Quaternary change within three major sub-regions. In addition, the drainage lines of the region have contributed both geomorphological and archaeological information.

Firstly, the eastern highlands have provided a setting for cold-climate weathering studies and periglacial processes, as well as featuring in the controversial debate on late Quaternary glaciation of the Drakensberg escarpment. Secondly, the western Free State panfield has contributed significantly to the geomorphic literature on the late Quaternary of the province. Thirdly, there is the southern and south eastern Kalahari. Finally, there are the drainage lines of the central and western Free State, and the Orange and Vaal rivers. The central Free State continues to offer some potential for weathering and slope process studies, but has not yielded much in terms of geomorphic evidence for Quaternary environmental change.

In conclusion, it is argued that what may prevent geomorphology from becoming moribund, or irrelevant with regard to Quaternary studies, are the prospects offered by advances in absolute dating techniques and remote sensing, particularly with regard to palaeo-drainage and pan-lunette suites in the western Free State. This is where the potential for future cutting edge geomorphological research into, in particular the late Quaternary evolution of this landscape appears, to lie.