Chronological framework for colluviation during the last 110 KYR in Kwazulu-Natal

Abstract

Luminescence dating techniques have been applied to colluvial sediments of the Masotcheni Formation are four sites in northern Natal. Derails of the thermoluminescence (TL) and infrared-stimulated luminescence (IRSL) results are given, as well as measurements of the radioactive content of the samples. The results suggest that the feldspar grains were well enough bleached by sunlight at deposition to allow dating by IRSL techniques. The ages obtained suggest that colluvial deposition occurred during late Oxygen Isotope Stage 5, after the peak of the Last Interglacial (Sub-stage 5e), resulting in the Dingaanstad Alloformation. No colluvial deposits were recorded from Stage 4. Further colluvial deposition, represented by the Nqutu Allomember, seems to have commenced early in Stage 3, following a period of donga erosion. A soil was then formed during Stage 3 in the top of this deposit at two of the sires, and this was covered by more colluvial deposits before Stage 3 ended. Evidence for late Holocene colluviation is also presented.