EPISODIC LATE QUATERNARY PALAEOGULLY EROSION IN NORTHERN KWAZULU NATAL, SOUTH-AFRICA

Hillslope deposits in northern KwaZulu-Natal, South Africa are incised by gullies (dongas) which expose sequences of buried palaeosols developed within a succession of discontinuity-bounded colluvial sedimentary units. Infilled and buried palaeogully topography attests to at least four geomorphic cycles, comprising gully cut-and-fill and palaeosol formation, on hillslopes in the region during the past 135 ka. Past attempts at dating colluvial stratigraphic units were limited to radiocarbon dating of associated palaeosol organic matter and authigenic soil carbonates. This study presents a preliminary set of Infra Red Stimulated Luminescence (IRSL) age determinations pertaining to deposition of the succession of colluvial units infilling and burying palaeogullies at several sites of stratigraphic, geochronological and palaeo-environmental importance in the region. Interpretation of the IRSL and C-14 dates in the context of cyclical hillslope processes suggests that past episodes of palaeogully erosion and infill were not synchronous and individual palaeosol landsurfaces were diachronous during the late Pleistocene.