Geomorphology of the upper Mkhomazi River basin, KwaZulu-Natal, South Africa, with emphasis on late Pleistocene colluvial deposits

ABSTRACT

We present a 1:50 000 scale geomorphological map of the upper Mkhomazi River basin, located in the foothills of the Drakensberg mountains in KwaZulu-Natal Province, South Africa. The sub-horizontal strata of the Permo-Triassic Beaufort Group forms plateau interfluves with a concave valley slope morphology. Locally, thick sequences of late Pleistocene colluvial deposits and associated buried paleosols (Masotcheni Formation) infill first-order tributary stream valleys and extend across the adjacent lower slopes. Surface runoff processes preferentially incise into the poorly consolidated, highly erodible sediments causing severe gully erosion that is responsible for widespread land degradation and desertification phenomena. The main purpose of this work is to derive a geomorphological map of the study area focussing on the erosional landforms to understand their spatial distribution and their relation to the colluvial deposits. Finally, a local and regional stratigraphic correlation of colluvial deposits and associated buried palaeosol profiles is proposed.

KEYWORDS:

• Geomorphological map
• KwaZulu-Natal (RSA)
• gully erosion
• rill-interrill erosion
• river terraces
• Masotcheni Formation

Acknowledgements

The authors are grateful to the Council for Geoscience office in Pietermaritzburg for logistical support. We thank the DLR and the TDX Science Team for providing Tandem-X data set of the study area.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

We would like to thank the ROCEEH project financed by Heidelberg Academy of Sciences and Humanities for traveling support. University of Tübingen provided field instruments and computing facilities. This research was also conducted with financial support of the University of Pavia.