Skip to main content
placeholder image

Cosmogenic 21Ne and 10Be reveal a more than 2 Ma alluvial fan flanking the Cape Mountains, South Africa

Journal Article


Abstract


  • Cosmogenic 21Ne and 10Be analyses across a subhorizontal fossil alluvial fan flanking the Cape Mountains near Laingsburg (Western Cape, South Africa) indicate a formation age for this fan of at least 2 Ma. Maximum erosion rates obtained from samples of quartzite ridges protruding through the fan alluvium deposits are very low (<~0.4 m/Ma) and analytically indistinguishable from those derived from pebbles from the fan surface (<~1.5 m/Ma). Our results are consistent with the low denudation rates obtained from other cosmogenic nuclide analyses and predicted by apatite fission-track and offshore sedimentation analyses for southern Africa during the Cenozoic. They integrate already existing substantial evidence to show that relative tectonic stability has prevailed across southern Africa throughout this period, and that the present-day large-scale topography is largely inherited from the Cretaceous and has been only minimally resculptured by denudation during the Cenozoic.

Authors


  •   Kounov, A (external author)
  •   Niedermann, S (external author)
  •   De Wit, Maarten (external author)
  •   Codilean, Alexandru Tiberiu.
  •   Viola, G (external author)
  •   Andreoli, M (external author)
  •   Christl, M (external author)

Publication Date


  • 2015

Citation


  • Kounov, A., Niedermann, S., De Wit, M. J., Codilean, A. T., Viola, G., Andreoli, M. & Christl, M. (2015). Cosmogenic 21Ne and 10Be reveal a more than 2 Ma alluvial fan flanking the Cape Mountains, South Africa. South African Journal of Geology, 118 (2), 129-144.

Scopus Eid


  • 2-s2.0-84942416767

Ro Metadata Url


  • http://ro.uow.edu.au/smhpapers/3335

Number Of Pages


  • 15

Start Page


  • 129

End Page


  • 144

Volume


  • 118

Issue


  • 2

Abstract


  • Cosmogenic 21Ne and 10Be analyses across a subhorizontal fossil alluvial fan flanking the Cape Mountains near Laingsburg (Western Cape, South Africa) indicate a formation age for this fan of at least 2 Ma. Maximum erosion rates obtained from samples of quartzite ridges protruding through the fan alluvium deposits are very low (<~0.4 m/Ma) and analytically indistinguishable from those derived from pebbles from the fan surface (<~1.5 m/Ma). Our results are consistent with the low denudation rates obtained from other cosmogenic nuclide analyses and predicted by apatite fission-track and offshore sedimentation analyses for southern Africa during the Cenozoic. They integrate already existing substantial evidence to show that relative tectonic stability has prevailed across southern Africa throughout this period, and that the present-day large-scale topography is largely inherited from the Cretaceous and has been only minimally resculptured by denudation during the Cenozoic.

Authors


  •   Kounov, A (external author)
  •   Niedermann, S (external author)
  •   De Wit, Maarten (external author)
  •   Codilean, Alexandru Tiberiu.
  •   Viola, G (external author)
  •   Andreoli, M (external author)
  •   Christl, M (external author)

Publication Date


  • 2015

Citation


  • Kounov, A., Niedermann, S., De Wit, M. J., Codilean, A. T., Viola, G., Andreoli, M. & Christl, M. (2015). Cosmogenic 21Ne and 10Be reveal a more than 2 Ma alluvial fan flanking the Cape Mountains, South Africa. South African Journal of Geology, 118 (2), 129-144.

Scopus Eid


  • 2-s2.0-84942416767

Ro Metadata Url


  • http://ro.uow.edu.au/smhpapers/3335

Number Of Pages


  • 15

Start Page


  • 129

End Page


  • 144

Volume


  • 118

Issue


  • 2