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Denudation rates and geomorphic evolution of the Cape
Mountains determined through cosmogenic dating using
10 Be and 21 Ne in quartz
1 T.Scharf, 2 A. Codilean, 3 M.J de Wit, S. 4 Niedermann,
1. AEON-University of Cape Town, South Africa, taryns1@gmail.com
2. Earth Surface Geochemistry, GFZ, Potsdam, Germany, codilean@gfz-potsdam.de
3. AEON-University of Cape Town, South Africa, maarten.dewit@uct.ac.za
4. Inorganic and Isotope Geochemistry, GFZ, Potsdam, Germany, nied@gfz-potsdam.de
ABSTRACT
The Cape Mountains, consisting of resistant quartzite, sandstones, as well as argillaceous material, form a
distinctive high relief area in comparison to the adjacent Karoo region to the north. The river systems draining the
southern ranges of the mountain system consist almost exclusively of short, near-linear rivers that have cut down
into the resistant rocks of the mountain ranges, leaving behind incised meanders and abandoned river terraces
within steep sided canyons.
The origin and timing of this Cape landscape remains unresolved. Fission track data suggests that the region was
largely exhumed in the Cretaceous, followed by possible further uplift in the Cenozoic. Whether this second-order
uplift took place continuously as an isostatic phenomenon, or as isolated tectonic uplift events, is unknown.
Previous cosmogenic data further inland of the Cape Mountains have yielded low recent erosion rates (