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Analysis of geological hiatus surfaces across Africa in the Cenozoic and implications for the timescales of convectively-maintained topography

Carena, S., H.-P. Bunge, and A.M. Friedrich (2019), Analysis of geological hiatus surfaces across Africa in the Cenozoic and implications for the timescales of convectively-maintained topography, Canadian Journal of Earth Sciences, doi:https://doi.org/10.1139/cjes-2018-0329.

Abstract
Geological maps are a powerful but underutilized tool to constrain geodynamic processes and models. Unraveling the Cenozoic elevation history of Africa and distinguishing between competing uplift and subsidence scenarios is of considerable interest to constrain the dynamic processes in the mantle beneath the continent. Here we explore continental-scale geological maps, and map temporal and spatial patterns of geological contacts, assuming that interregional-scale unconformable contacts (hiatus surfaces) on geological maps yield proxy-records of paleotopography and vertical motion. We find that significant differences in the spatial extent of interregional-scale hiatus surfaces exist across Africa at the time scale of geologic series. A significant expansion of total unconformable area at the base of Miocene strongly suggests that the Oligocene was a period of uplift in most of Africa. In southern Africa there is a complete absence of marine sediments in both Oligocene and Pleistocene. This pattern suggests that southernmost Africa reached a high elevation in the Oligocene, subsided in the Miocene-Pliocene, and has been high again since latest Pliocene or Pleistocene times. Our hiatus mapping results support a dynamic origin of Africa’s topography. In particular, they point to elevation changes at the time scale of geologic series (ten to a few tens of millions of years), which is considerably smaller than the mantle transit time. The time scale for elevation changes in Africa is thus comparable to the rapid spreading-rate variations in the South Atlantic, which have been geodynamically linked to African elevation changes through pressure-driven upper mantle flow.
BibTeX
@article{id2459,
  author = {S. Carena and H.-P. Bunge and A.M. Friedrich},
  journal = {Canadian Journal of Earth Sciences},
  title = {{Analysis of geological hiatus surfaces across Africa in the Cenozoic and implications for the timescales of convectively-maintained topography}},
  year = {2019},
  doi = {https://doi.org/10.1139/cjes-2018-0329},
}
EndNote
%0 Journal Article
%A Carena, S.
%A Bunge, H.-P.
%A Friedrich, A.M.
%D 2019
%J Canadian Journal of Earth Sciences
%T Analysis of geological hiatus surfaces across Africa in the Cenozoic and implications for the timescales of convectively-maintained topography
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Printed 15. Dec 2019 22:42