Okwa Belt

Fig. 1. Map showing station locations, topography and principal geological provinces in the region of study within southern Africa, Fifty-five broadband (REFTEK/STS-2) stations were installed in April 1997 in South Africa, Botswana and Zimbabwe. Stations in light blue were redeployed in April 1998 to sites indicated in yellow. A total of 82 sites were occupied over the two year deployment. In addition, three global seismic network broadband stations (white triangles) are located in the region and their data incorporated in the analysis. The array extends from the Cape Fold Belt in the south, through the Proterozoic Namaqua-Natal Mobile Belt, across the Kaapvaal Craton and Bushveld Province, through the Archaean Limpopo Mobile Belt and into the Zimbabwe Craton. On the west, the array covers part of the Kheis and Okwa Proterozoic Fold and Thrust Belts of Botswana and western South Africa. To the east, the array extends into the Early Archaean Barberton terrane, near the NW border with Swaziland. Published in James et al., GRL28, 2001, fig. 1.

Fig. 11. Colour-coded contour map of depth to Moho beneath the southern Africa array based on phasing depth images of Figure 2 (from Nguuri et al. 2001). Crustal thickness colour scale is shown on right. Thin crust is associated with undisturbed areas of craton, particularly in the southern and eastern parts of the Kaapvaal Craton and in the Zimbabwe Craton north of the Limpopo Belt. Greater crustal thickness is associated with the Bushveld region and its westward extension into the Okwa and Magondi Belts and with the Central Zone of the Limpopo Belt and the Proterozoic Namaqua-Natal Mobile Belt.

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