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., and Webb, Susan J. (2012) Shear wave velocity structure of the Bushveld Complex, South Africa. Tectonophysics, 554-557. pp. 83-104.

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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.

Item ID: 23558
Item Type: Article (Research - C1)
ISSN: 0040-1951
Keywords: Bushveld Complex; continuous-sheet model; dipping-sheet model; joint inversion; receiver functions; Rayleigh wave group velocities
Additional Information:

This article is an open access article distributed under the terms and conditions of Elsevier's Open Access Articles policy: http://www.elsevier.com/wps/find/intro.cws_home/open_access_articles

Date Deposited: 03 Oct 2012 05:43
FoR Codes: 04 EARTH SCIENCES > 0403 Geology > 040313 Tectonics @ 20%
04 EARTH SCIENCES > 0404 Geophysics > 040407 Seismology and Seismic Exploration @ 60%
04 EARTH SCIENCES > 0403 Geology > 040304 Igneous and Metamorphic Petrology @ 20%
SEO Codes: 84 MINERAL RESOURCES (excl. Energy Resources) > 8401 Mineral Exploration > 840199 Mineral Exploration not elsewhere classified @ 10%
97 EXPANDING KNOWLEDGE > 970104 Expanding Knowledge in the Earth Sciences @ 90%
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