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Geoecodynamics and geobiological fingerprints of the
Kalahari epeirogeny: linking tectonism, drainage, and
phylogeography
F.P.D. Cotterill 1,2 , M.J. de Wit 1
1 AEON - Africa Earth Observatory Network
Department of Geological Sciences, University of Cape Town, Rondebosch 7701, South Africa
2 Department of Molecular and Cell Biology, University of Cape Town, Rondebosch 7701, South Africa
ABSTRACT
This paper summarises recent progress in geoecodynamics research on landscape evolution of the Kalahari Plateau.
Expanding the scope of geobiology, the theory and methods of geoecodynamics quantifies the tenures of geobiotic
entities in landscapes, within the framework of geomorphological and geospheric evolution. Geoecodynamics
centres on deciphering phylogeographic records of stenotopic species; molecular dating of DNA sequences
constrains timings of speciation and dispersal events in these biotic indicators, and quantifies each event as an
individualistic response to disruption of a landform. Our studies of biotic indicators reveal how geobiological
signatures across Africa’s Kalahari plateau can decipher the tempo and mode of late Cenozoic landscape evolution.
We demonstrate that this novel methodology obtains spatio-temporal constraints on episodes of tectonism.
Quantified geobiological signatures revealed in these biotic indicators of landscape evolution constrain where and
when both the drainage and biogeography of the Kalahari plateau changed. We interpret these signatures, preserved
in the biosphere, to reflect impacts of deep geosphere processes on landscapes; so these tight links between biotic
and palaeo-drainage dynamics constitute synergistic responses to the pulses of tectonics that altered river topology
and lacustrine environments. A synthesis of these biotic histories reveals how biodiversity dynamics responded to
changes in depocentres and drainage nets. We employ a synthesis of phylogeographic evidence to tighten spatiotemporal
resolution on these events. It enables us to map where and when geospheric processes impacted on earth
surface processes. In combination, phylogeography and molecular dating of biotic indicators confers both
geochronological resolution, and spatial precision, to quantify geobiological events as fingerprints of tectonic
pulses. This narrative of geobiological history is interpreted to reflect recurrent epeirogeny across the African plate,
which has reconfigured the Kalahari Plateau through the Plio-Pleistocene. Its unprecedented spatio-temporal
resolution quantifies a southwest spreading propagation of tectonics, to constrain the rate of individuation of the
Kalahari subplate.
KEYWORDS: Kalahari epeirogeny, tectonism, speciation, fishes, phylogeography, molecular clocks, drainage
evolution, African biogeography, geomorphology, molecular dating
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