Peridotites southern Africa

Canil D. (1992) Orthopyroxene stability along the peridotite solidus and the origin of cratonic lithosphere beneath southern Africa. Earth Planet. Sci. Lett. Ill, 83-95. 

Gunther M. and Jagoutz E. (1994) isotopic disequilibria (Sm/ Nd, Rb/Sr) between minerals of coarse grained, low temperature peridotites from Kimberely floors, southern Africa. In Kimberlites, Related Rocks and Mantle Xenoliths, Proc. 5th Int. Kimberlite Conf, Araxa, Brazil. CPRM. Spec. 

Shimizu N. (1999) Young geochemical features in cratonic peridotites from southern Africa and Siberia. In Mantle Petrology Field Observations and High Pressure Experimentation (eds. Y. Fei, C. M. Bertka, and B. Mysen). The Geochemical Society, Houston, vol. 6, pp. 47-55. 

Boyd F. R. (1987) High- and low-temperature garnet peridotite xenoliths and their possible relation to the lithosphere-asthenosphere boundary beneath southern Africa. In Mantle Xenoliths (ed. P. H. Nixon). Wiley, London, pp. 403 -412. 

Fig. 2. Schematic map showing mean redepletion model ages determined for peridotite nodules from kimberlite pipes erupted in southern Africa. Cratonic regions are outlined in yellow, the Limpopo Belt in brown. Solid coloured circles indicate individual kimberlite pipes from which several xenoliths have been analysed. Published in Carlson et al., GSA Today, 2000, February issue, fig. 4.

Fig. 10. Histograms of Trd ages for on- and off-craton peridotites from southern Africa co-plotted with histograms of olivine mg-numbers. Kaapvaal low-L peridotites xenohths, n = 96. Data from Nixon et al. (1983), Walker et al. (1989), Pearson et al. (1995a), Carlson et al. (1999), Menzies et al. (1999) and Irvine et al. (2002). Lrd ages for peridotite xenoliths from kimberlites from East Griqualand, 170 km from the Lesotho on-craton kimberlites (Pearson et al. 1998) and for peridotites from the Farm Louwrencia kimberlite. Southern Namibia (Pearson et al. 1994 Pearson 1999a). It should be noted that no Archaean Trd ages are observed for off-craton peridotites. Olivine compositional data from Boyd Nixon (1979), Nixon (1987) and Boyd (unpubl. data).

To date, Re-Os isotope studies of peridotite xenolith suites, taken to be representative of the lithospheric mantle beneath continents, reveal that although some lithospheric mantle began to form beneath continents in Palaeo- to Mesoarch-aean time, major crustal differentiation events continued until Neoarchaean time when, at least in southern Africa, significant volumes of lithospheric mantle formed and stabilized the newly accreted continent. On the Kaapvaal Craton, major magmatic events such as that which formed the Bushveld intrusion, substantially modified or introduced new material into the lithospheric mantle (Carlson et al. 1999) and the lower crust (Schmitz Bowring 2000), but the craton retained its integrity for another 2 Ga. 

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