Original paper

Morphotectonics and denudation in the landform history of the Namibian Great Escarpment landscapes

Kempf, Jürgen


The Great Escarpment is the most conspicuous mega-geomorphological landform of southern Africa. Its development on a passive continental margin during the Cainozoic has been the object of considerable geomorphological debate, the principal issue being as to whether the escarpment has to be regarded as the result of slope retreat to its present position of the rift shoulder originated with the onset of Lower Cretaceous spreading of the South Atlantic, or rather as a Cainozoic landform developed in situ without any significant slope retreat. In the present paper the Namibian section of the Great Escarpment is interpreted as a complex landscape that has primarily been the result of uplift and eastward tilting of the subcontinent as an expression of the South African superswell. These neotectonic processes have created a number of partly widespread upwarps along the western rim of the subcontinent, together with tension structures, faults, monoclines and flexures. The tectonic history is embedded in a denudation history of extremely high amounts and rates towards the incipient South Atlantic. The isostatic reactions to sediment loading on the continental shelf enhanced tectonic activity along the adjacent passive continental margin. It was mainly etchplanation, the pattern of which was governed by the tectonic pattern over large parts of the Cainozoic. Also Late Tertiary and even Quaternary phases have been affected by the tectonic movements of the superswell, as will be demonstrated by a series of geological and geomorphological cross sections through the various types of landscapes of the Great Escarpment.