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Continental mantle signature of Bushveld magmas and coeval diamonds


The emplacement of the 2.05-billion-year-old Bushveld complex, the world’s largest layered intrusion and platinum-group element (PGE) repository1, is a singular event in the history of the Kaapvaal craton of southern Africa2,3,4, one of Earth’s earliest surviving continental nuclei. In the prevailing model for the complex’s mineralization, the radiogenic strontium and osmium isotope signatures of Bushveld PGE ores are attributed to continental crustal contamination of the host magmas5,6,7,8,9,10,11. The scale of the intrusion and lateral homogeneity of the PGE-enriched layers1, however, have long been problematical for the crustal contamination model, given the typically heterogeneous nature of continental crust. Furthermore, the distribution of Bushveld magmatism matches that of seismically anomalous underlying mantle3,12, implying significant interaction before emplacement in the crust. Mineral samples of the ancient 200-km-deep craton keel, encapsulated in macrodiamonds and entrained by proximal kimberlites, reveal the nature of continental mantle potentially incorporated by Bushveld magmas13,14. Here we show that sulphide inclusions in 2-billion-year-old diamonds from the 0.5-billion-year-old Venetia and 1.2-billion-year-old Premier kimberlites (on opposite sides of the complex) have initial osmium isotope ratios even more radiogenic than those of Bushveld sulphide ore minerals6,15. Sulphide Re–Os and silicate Sm–Nd and Rb–Sr isotope compositions indicate that continental mantle harzburgite and eclogite components, in addition to the original convecting mantle magma, most probably contributed to the genesis of both the diamonds and the Bushveld complex. Coeval diamonds provide key evidence that the main source of Bushveld PGEs is the mantle rather than the crust.

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Figure 1: Sketch map of the Kaapvaal and Zimbabwe cratons (light blue) and intervening Limpopo belt (dark blue) of southern Africa (following ref. 33).
Figure 2: Re–Os isochron diagram for sulphide inclusions in Premier and Venetia diamonds.
Figure 3: Isotope correlation diagrams comparing Bushveld rocks and PGE sulphide ore minerals 6, 8, 9, 15 to potential mantle source components 2.05 Gyr ago.


  1. Eales, H. V. & Cawthorn, R. G. in Layered Intrusions (ed. Cawthorn, R. G.) 181–229 (Elsevier Science, Amsterdam, 1996)

    Book  Google Scholar 

  2. de Wit, M. J. et al. Formation of an Archaean continent. Nature 357, 553–562 (1992)

    ADS  Article  Google Scholar 

  3. James, D. E., Fouch, M. J., VanDecar, J. C., van der Lee, S. & Group, K. S. Tectospheric structure beneath southern Africa. Geophys. Res. Lett. 28, 2485–2488 (2001)

    ADS  Article  Google Scholar 

  4. Eglington, B. M. & Armstrong, R. A. The Kaapvaal Craton and adjacent orogens, southern Africa: a geochronological database and overview of the geological development of the craton. South Afr. J. Geol. 107, 13–32 (2004)

    Article  Google Scholar 

  5. Kruger, F. J. & Marsh, J. S. Significance of 87Sr/86Sr ratios in the Merensky cyclic unit of the Bushveld Complex. Nature 298, 53–55 (1982)

    ADS  CAS  Article  Google Scholar 

  6. McCandless, T. E. & Ruiz, J. Osmium isotopes and crustal sources for platinum-group mineralization in the Bushveld Complex, South Africa. Geology 19, 1225–1228 (1991)

    ADS  CAS  Article  Google Scholar 

  7. McCandless, T. E., Ruiz, J., Adair, B. I. & Freydier, C. Re-Os isotope and Pd/Ru variations in chromitites from the Critical Zone, Bushveld Complex, South Africa. Geochim. Cosmochim. Acta 63, 911–923 (1999)

    ADS  CAS  Article  Google Scholar 

  8. Schoenberg, R., Kruger, F. J., Nägler, T. F., Meisel, T. & Kramers, J. D. PGE enrichment in chromitite layers and the Merensky Reef of the western Bushveld Complex; a Re-Os and Rb-Sr isotope study. Earth Planet. Sci. Lett. 172, 49–64 (1999)

    ADS  CAS  Article  Google Scholar 

  9. Maier, W. D., Arndt, N. T. & Curl, E. A. Progressive crustal contamination of the Bushveld Complex; evidence from Nd isotopic analyses of the cumulate rocks. Contrib. Mineral. Petrol. 140, 316–327 (2000)

    ADS  CAS  Article  Google Scholar 

  10. Prevec, S. A., Ashwal, L. D. & Mkaza, M. S. Mineral disequilibrium in the Merensky Reef, western Bushveld Complex, South Africa; new Sm-Nd isotopic evidence. Contrib. Mineral. Petrol. 149, 306–315 (2005)

    ADS  CAS  Article  Google Scholar 

  11. Harris, C., Pronost, J. J. M., Ashwal, L. D. & Cawthorn, R. G. Oxygen and hydrogen isotope stratigraphy of the Rustenburg Layered Suite, Bushveld Complex; constraints on crustal contamination. J. Petrol. 46, 579–601 (2005)

    CAS  Article  Google Scholar 

  12. Shirey, S. B. et al. Diamond genesis, seismic structure, and evolution of the Kaapvaal-Zimbabwe craton. Science 297, 1683–1686 (2002)

    ADS  CAS  Article  Google Scholar 

  13. Richardson, S. H., Gurney, J. J., Erlank, A. J. & Harris, J. W. Origin of diamonds in old enriched mantle. Nature 310, 198–202 (1984)

    ADS  CAS  Article  Google Scholar 

  14. Richardson, S. H., Harris, J. W. & Gurney, J. J. Three generations of diamonds from old continental mantle. Nature 366, 256–258 (1993)

    ADS  CAS  Article  Google Scholar 

  15. Hart, S. R. & Kinloch, E. D. Osmium isotope systematics in Witwatersrand and Bushveld ore deposits. Econ. Geol. 84, 1651–1655 (1989)

    CAS  Article  Google Scholar 

  16. Richardson, S. H., Shirey, S. B., Harris, J. W. & Carlson, R. W. Archean subduction recorded by Re-Os isotopes in eclogitic sulfide inclusions in Kimberley diamonds. Earth Planet. Sci. Lett. 191, 257–266 (2001)

    ADS  CAS  Article  Google Scholar 

  17. Schmitz, M. D., Bowring, S. A., de Wit, M. J. & Gartz, V. Subduction and terrane collision stabilized the western Kaapvaal craton tectosphere 2.9 billion years ago. Earth Planet. Sci. Lett. 222, 363–376 (2004)

    ADS  CAS  Article  Google Scholar 

  18. Boshoff, R. et al. Geological history of the Central Zone of the Limpopo Complex: the West Alldays area. J. Geol. 114, 699–716 (2006)

    ADS  Article  Google Scholar 

  19. Davies, G., Cawthorn, R. G., Barton, J. M. & Morton, M. Parental magma to the Bushveld Complex. Nature 287, 33–35 (1980)

    ADS  CAS  Article  Google Scholar 

  20. Cawthorn, R. G. & Walraven, F. Emplacement and crystallization time for the Bushveld Complex. J. Petrol. 39, 1669–1687 (1998)

    ADS  CAS  Article  Google Scholar 

  21. Hamilton, P. J. isotope and trace element studies of the Great Dyke and Bushveld mafic phase and their relation to early Proterozoic magma genesis in southern Africa. J. Petrol. 18, 24–52 (1977)

    ADS  CAS  Article  Google Scholar 

  22. Harmer, R. E. & Sharpe, M. R. Field relations and strontium isotope systematics of the marginal rocks of the eastern Bushveld Complex. Econ. Geol. 80, 813–837 (1985)

    CAS  Article  Google Scholar 

  23. Lee, C. A. & Butcher, A. R. Cyclicity in the Sr isotope stratigraphy through the Merensky and Bastard Reef units, Atok section, eastern Bushveld Complex. Econ. Geol. 85, 877–883 (1990)

    CAS  Article  Google Scholar 

  24. Mathez, E. A. & Kent, A. J. R. Variable initial Pb isotopic compositions of rocks associated with the UG2 chromitite, eastern Bushveld Complex. Geochim. Cosmochim. Acta 71, 5514–5527 (2007)

    ADS  CAS  Article  Google Scholar 

  25. Carlson, R. W. et al. in The J. B. Dawson Volume (Proc. 7th Internat. Kimberlite Conf.) (eds Gurney, J. J., Gurney, J. L., Pascoe, M. D. & Richardson, S. H.) 99–108 (Red Roof Design, Cape Town, 1999)

    Google Scholar 

  26. Westerlund, K. J. et al. A subduction wedge origin for Paleoarchean peridotitic diamonds and harzburgites from the Panda kimberlite, Slave craton: evidence from Re-Os isotope systematics. Contrib. Mineral. Petrol. 152, 275–294 (2006)

    ADS  MathSciNet  CAS  Article  Google Scholar 

  27. Mitchell, R. H. & Keays, R. R. Abundance and distribution of gold, palladium and iridium in some spinel and garnet lherzolites: implications for the nature and origin of precious metal-rich intergranular components in the upper mantle. Geochim. Cosmochim. Acta 45, 2425–2433 (1981)

    ADS  CAS  Article  Google Scholar 

  28. Shirey, S. B. et al. Archean emplacement of eclogitic components into the lithospheric mantle during formation of the Kaapvaal Craton. Geophys. Res. Lett. 28, 2509–2512 (2001)

    ADS  CAS  Article  Google Scholar 

  29. Nägler, T. F., Kramers, J. D., Kamber, B. S., Frei, R. & Prendergast, M. D. A. Growth of subcontinental lithospheric mantle beneath Zimbabwe started at or before 3.8 Ga; Re-Os study on chromites. Geology 25, 983–986 (1997)

    ADS  Article  Google Scholar 

  30. Allègre, C. J. & Luck, J. M. Osmium isotopes as petrogenetic and geological tracers. Earth Planet. Sci. Lett. 48, 148–154 (1980)

    ADS  Article  Google Scholar 

  31. Sharp, Z. D. Principles of Stable Isotope Geochemistry Ch. 11 (Prentice Hall, Englewood Cliffs, New Jersey, 2006)

    Google Scholar 

  32. Lambert, D. D. et al. Re-Os and Sm-Nd isotope geochemistry of the Stillwater Complex, Montana; implications for the petrogenesis of the J-M Reef. J. Petrol. 35, 1717–1753 (1994)

    ADS  CAS  Article  Google Scholar 

  33. McCourt, S., Kampunzu, A. B., Bagai, Z. & Armstrong, R. A. The crustal architecture of Archaean terranes in northeastern Botswana. South Afr. J. Geol. 107, 147–158 (2004)

    Article  Google Scholar 

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We thank De Beers for donation of rare diamond specimens; R. W. Carlson and J. W. Harris for collaboration on related diamond projects; R. J. Hemley, C. Yan and J. Lai for access to diamond cutting and polishing facilities; and T. Mock, M. Horan and C. Hadidiacos for analytical laboratory help. This work was supported by the Carnegie Institution of Washington and NSF grant EAR-0310059 to S.B.S.

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Correspondence to Stephen H. Richardson.

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Richardson, S., Shirey, S. Continental mantle signature of Bushveld magmas and coeval diamonds. Nature 453, 910–913 (2008).

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