Late Quaternary hillslope evolution recorded in eastern South African colluvial badlands

摘要

Infrared stimulated luminescence (IRSL) ages have been obtained from a sequence of sandy colluvial deposits in northern KwaZulu-Natal. Comparison of the IRSL ages on sand-sized, potassium-rich feldspars, with radiocarbon dates on A-horizon organic matter from buried palaeosols within the colluvial succession shows good agreement between the dating techniques. When compared with palaeoenvironmental records, the data suggest that the colluvium accumulated during arid stages of the Late Quaternary, whilst pedogenesis repeatedly occurred at intervals of hillslope stability which may reflect periods of greater humidity. Temperature does not seem to have been a forcing factor in the landscape development. Extensive colluviation took place during the arid Last Glacial Maximum, but the occurrence of several palaeosols indicates that it was a time of fluctuating climatic conditions.