Geology and landscape evolution of the highlands and escarpments of western Angola and Namibia


  • RM Miller PO Box 11222, Windhoek, Namibia


Angola, escarpments, geology, highlands, landscape evolution, Namibia


The bedrock geology of Angola and Namibia has been built by rifting, continental drift, ocean formation, sedimentary deposition in both marine and continental environments, continental collision and mountain building since the Archaean. The palaeo-climates that followed, particularly during humid periods lasting tens of millions of years, have shaped the surface morphology. Erosion, removal of the humid-climate regoliths and gradual exposure of the present landscape started approximately 70 million years ago. The elevated escarpment regions of western Angola and Namibia are the result of scarp retreat after the breakup of Gondwana. They are underlain by igneous, sedimentary and metamorphic rocks ranging in age from Archaean to early Cretaceous. Inselbergs consist of weather-resistant igneous rocks of highly variable compositions such as granite, syenite, gabbro, basalt, rhyolite and carbonatite. Soils derived from the variable chemistry of these rocks in combination with the microclimates at different elevations and different locations provide the basis for the evolution of endemism.