Shear wave velocity structure of the Bushveld Complex, South Africa

Eldridge M. Kgaswane, Andrew A. Nyblade, Raymond J. Durrheim, Jordi Julià, Paul H.G.M. Dirks, Susan J. Webb

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

The structure of the crust in the environs of the Bushveld Complex has been investigated by jointly inverting high-frequency teleseismic receiver functions and 2-60. s period Rayleigh wave group velocities for 16 broadband seismic stations located across the Bushveld Complex. Group velocities for 2-15. s periods were obtained from surface wave tomography using local and regional events, while group velocities for 20-60. s periods were taken from a published model. 1-D shear wave velocity models obtained for each station show the presence of thickened crust in the center of the Bushveld Complex and a region at the base of the crust where shear wave velocities exceed 4.0. km/s. The shear wave velocity models also suggest that velocities in some upper crustal layers may be as high as 3.7-3.8. km/s, consistent with the presence of mafic lithologies. These results favor a continuous-sheet model for the Bushveld Complex in which the outcropping mafic layers of the western and eastern limbs are continuous at depth beneath the center of the complex. However, detailed modeling of receiver functions at one station within the center of the complex indicates that the mafic layering may be locally disrupted due to thermal diapirism triggered by the emplacement of the Bushveld Complex or thermal and tectonic reactivation at a later time.

Original languageEnglish (US)
Pages (from-to)83-104
Number of pages22
JournalTectonophysics
Volume554-557
DOIs
StatePublished - Jul 25 2012

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Republic of South Africa
velocity structure
S waves
wave velocity
S-wave
group velocity
crusts
stations
crust
receivers
lithology
Rayleigh waves
wave group
limbs
diapirism
surface waves
Rayleigh wave
tectonics
reactivation
tomography

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Earth-Surface Processes

Cite this

Kgaswane, E. M., Nyblade, A. A., Durrheim, R. J., Julià, J., Dirks, P. H. G. M., & Webb, S. J. (2012). Shear wave velocity structure of the Bushveld Complex, South Africa. Tectonophysics, 554-557, 83-104. https://doi.org/10.1016/j.tecto.2012.06.003
Kgaswane, Eldridge M. ; Nyblade, Andrew A. ; Durrheim, Raymond J. ; Julià, Jordi ; Dirks, Paul H.G.M. ; Webb, Susan J. / Shear wave velocity structure of the Bushveld Complex, South Africa. In: Tectonophysics. 2012 ; Vol. 554-557. pp. 83-104.
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Kgaswane, EM, Nyblade, AA, Durrheim, RJ, Julià, J, Dirks, PHGM & Webb, SJ 2012, 'Shear wave velocity structure of the Bushveld Complex, South Africa', Tectonophysics, vol. 554-557, pp. 83-104. https://doi.org/10.1016/j.tecto.2012.06.003

Shear wave velocity structure of the Bushveld Complex, South Africa. / Kgaswane, Eldridge M.; Nyblade, Andrew A.; Durrheim, Raymond J.; Julià, Jordi; Dirks, Paul H.G.M.; Webb, Susan J.

In: Tectonophysics, Vol. 554-557, 25.07.2012, p. 83-104.

Research output: Contribution to journalArticle

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AU - Webb, Susan J.

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