Shear-wave velocity structure of the southern African upper mantle: Implications for Craton structure and plateau uplift

A. L. White-Gaynor*, A. A. Nyblade, R. J. Durrheim, R. Raveloson, M. van der Meijde, I. Fadel, H. Paulssen, M. Kwadiba, O. Ntibinyane, N. Titus, M. Sitali

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

We present a 3D shear-wave velocity model of the southern African upper mantle developed using 30–200 s period Rayleigh waves recorded on regional seismic networks spanning the subcontinent. The model shows high velocities (∼4.7–4.8 km/s) at depths of 50–250 km beneath the Archean nucleus and several surrounding Paleoproterozoic and Mesoproterozoic terranes, placing the margin of the greater Kalahari Craton along the southern boundary of the Damara Belt and the eastern boundaries of the Gariep and Namaqua-Natal belts. At depths ≥250 km, there is little difference in velocities beneath the craton and off-craton regions, suggesting that the cratonic lithosphere extends to depths of about 200–250 km. Upper mantle velocities beneath uplifted areas of southern Africa are higher than the global average and significantly higher than beneath eastern Africa, indicating there that is little thermal modification of the upper mantle present today beneath the Southern African Plateau.

Original languageEnglish
Pages (from-to)1-10
Number of pages10
JournalGeophysical research letters
Volume48
Issue number7
Early online date16 Feb 2021
DOIs
Publication statusPublished - 16 Apr 2021

Keywords

  • cratonic structure
  • plateau uplift
  • Southern Africa
  • surface wave tomography
  • Upper Mantle
  • ITC-ISI-JOURNAL-ARTICLE

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