Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

Re–Os isotopic evidence for long-lived heterogeneity and equilibration processes in the Earth's upper mantle


The geochemical composition of the Earth's upper mantle1,2,3 is thought to reflect 4.5 billion years of melt extraction, as well as the recycling of crustal materials. The fractionation of rhenium and osmium during partial melting in the upper mantle makes the Re–Os isotopic system well suited for tracing the extraction of melt and recycling of the resulting mid-ocean-ridge basalt3. Here we report osmium isotope compositions of more than 700 osmium-rich platinum-group element alloys derived from the upper mantle. The osmium isotopic data form a wide, essentially gaussian distribution, demonstrating that, with respect to Re–Os isotope systematics, the upper mantle is extremely heterogeneous. As depleted and enriched domains can apparently remain unequilibrated on a timescale of billions of years, effective equilibration seems to require high degrees of partial melting, such as occur under mid-ocean ridges or in back-arc settings, where percolating melts enhance the mobility of both osmium and rhenium. We infer that the gaussian shape of the osmium isotope distribution is the signature of a random mixing process between depleted and enriched domains, resulting from a ‘plum pudding’ distribution in the upper mantle, rather than from individual melt depletion events.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Map showing the distribution of ultramafic rock in southwest Oregon and northwest California and major rivers transporting chromite and platinoids to the Pacific beaches.
Figure 2: Histograms of Os isotope compositions of more than 700 mantle-derived iridosmine and osmiridium grains from ultramafic rock in northwest California and southwest Oregon.

Similar content being viewed by others


  1. Hofmann, A. W. Mantle geochemistry: the message from oceanic volcanism. Nature 385, 219–229 (1997)

    Article  ADS  CAS  Google Scholar 

  2. Zindler, A. & Hart, S. Chemical Geodynamics. Annu. Rev. Earth Planet. Sci. 14, 493–571 (1986)

    Article  ADS  CAS  Google Scholar 

  3. Shirey, S. B. & Walker, R. J. The Re-Os isotope system in cosmochemistry and high-temperature geochemistry. Annu. Rev. Earth Planet. Sci. 26, 423–500 (1998)

    Article  ADS  CAS  Google Scholar 

  4. Shen, J. J., Papanastassiou, D. A. & Wasserburg, G. J. Precise Re-Os determinations and systematics of iron meteorites. Geochim. Cosmochim. Acta 60, 2887–2900 (1996)

    Article  ADS  CAS  Google Scholar 

  5. Hauri, E. & Hart, S. R. Rhenium abundances and systematics in oceanic basalts. Chem. Geol. 139, 185–205 (1997)

    Article  ADS  CAS  Google Scholar 

  6. Walker, R. J., Prichard, H. M., Ishiwatari, A. & Pimentel, M. The osmium isotopic composition of convecting upper mantle deduced from ophiolite chromites. Geochim. Cosmochim. Acta 66, 329–345 (2002)

    Article  ADS  CAS  Google Scholar 

  7. Lee, C. T. A. The osmium isotopic composition of the Earth's convecting mantle. Earth Planet. Sci. Lett. (submitted)

  8. Hattori, K. & Hart, S. R. Osmium-isotope ratios of platinum-group minerals associated with ultramafic intrusions: Os-isotope evolution of the oceanic mantle. Earth Planet. Sci. Lett. 107, 499–514 (1991)

    Article  ADS  CAS  Google Scholar 

  9. Parkinson, I. J., Hawkesworth, C. J. & Cohen, A. S. Ancient mantle in a modern arc: Osmium isotopes in Izu-Bonin-Mariana forearc peridotites. Science 281, 2011–2013 (1998)

    Article  ADS  CAS  Google Scholar 

  10. Brandon, A., Snow, J. E., Walker, R. J., Morgan, J. W. & Mock, T. D. 190Pt-186Os and 187Re-187Os systematics of abyssal peridotites. Earth Planet. Sci. Lett. 177, 319–335 (2000)

    Article  ADS  CAS  Google Scholar 

  11. Burton, K., Schiano, P., Birck, J.-L. & Allegre, C. J. Osmium isotope disequilibrium between mantle minerals in a spinel-Iherzolite. Earth Planet. Sci. Lett. 172, 311–322 (1999)

    Article  ADS  CAS  Google Scholar 

  12. Burton, K. et al. The distribution and behaviour of rhenium and osmium among mantle minerals and the age of the lithospheric mantle beneath Tanzania. Earth Planet. Sci. Lett. 183, 93–106 (2000)

    Article  ADS  CAS  Google Scholar 

  13. Coleman, R. G. Ophiolites and Oceanic Crust (eds Dilek, Y., Moores, E., Elthon, D. & Nicolas, A.) 351–364 (Geological Society of America Special Paper, Boulder, Colorado, 2000)

    Google Scholar 

  14. Capri, L. J., Harris, D. C. & Weiser, T. W. Mineralogy and distribution of platinum-group mineral (PGM) placer deposits of the world. Explor. Mining Geol. 5, 73–167 (1996)

    Google Scholar 

  15. Stockman, H. & Hlava, P. F. Platinum-group minerals in alpine chromitites from southwestern Oregon. Econ. Geol. 79, 491–508 (1984)

    Article  CAS  Google Scholar 

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

    Article  ADS  CAS  Google Scholar 

  17. Clark, W. B. Platinum. Mineral Inform. Serv. Califor. Div. Mines Geol. 23, 115–122 (1970)

    Google Scholar 

  18. Meisel, T., Walker, R. J., Irving, A. J. & Lorand, J.-P. Osmium isotopic compositions of mantle xenoliths: A global perspective. Geochim. Cosmochim. Acta 65, 1311–1323 (2001)

    Article  ADS  CAS  Google Scholar 

  19. Standish, J. J., Hart, S. R., Blusztajn, J., Dick, H. J. B. & Lee, K. L. Abyssal peridotite osmium isotopic compositions from Cr-spinel. Geochem. Geophys. Geosyst. 3(1), 10.1029/2001GC000161 (2002)

  20. Leblanc, M. Ophiolite Genesis and Evolution of the Oceanic Lithosphere (eds Peters, Tj., Nicolas, A. & Coleman, R. G.) 231–260 (Ministry of Petroleum and Minerals, Sultanate of Oman, 1991)

    Book  Google Scholar 

  21. Auge, T. & Johan, Z. Mineral Deposits in the European Community (eds Boissonnas, J. & Omenetto, P.) 267–288 (Springer, Heidelberg, 1988)

    Book  Google Scholar 

  22. Kelemen, P. B., Dick, H. J. B. & Quick, J. E. Formation of harzburgite by pervasive melt/rock reaction in the upper mantle. Nature 358, 635–641 (1992)

    Article  ADS  CAS  Google Scholar 

  23. Niu, Y., Langmuir, C. H. & Kinzler, R. J. The origin of abyssal peridotites: a new perspective. Earth Planet. Sci. Lett. 152, 251–265 (1997)

    Article  ADS  CAS  Google Scholar 

  24. Sleep, N. Tapping of magmas from ubiquitous mantle heterogeneities: An alternative to mantle plumes? J. Geophys. Res. 89, 10029–10041 (1984)

    Article  ADS  CAS  Google Scholar 

  25. Anderson, D. L. The statistics of helium isotopes along the global spreading ridge system and the central limit theorem. Geophys. Res. Lett. 27, 2401–2404 (2000)

    Article  ADS  Google Scholar 

  26. Anderson, D. L. A statistical test of the two reservoir model for helium isotopes. Earth Planet. Sci. Lett. 193, 77–82 (2001)

    Article  ADS  CAS  Google Scholar 

  27. Meibom, A. & Frei, R. Evidence for an ancient osmium isotopic reservoir in earth. Science 296, 516–518 (2002)

    Article  ADS  CAS  Google Scholar 

  28. Page, N. J., Haffty, J. & Ramp, L. Occurrence of platinum group metals in ultramafic rocks of the Medford-Coos Bay 2 degree quadrangles, southwestern Oregon. (Map MF-694, 1:250,000, USGS Miscellaneous Field Studies, Washington DC, 1975).

  29. Griggs, A. B. Chromite-bearing beach sands of the southern part of the coast of Oregon. USGS Bull. 945-E, 113–150 (1945)

    Google Scholar 

Download references


We thank the Naturhistoriches Museum in Vienna (G. Kurat), and Chicago Field Museum (M. Wadhwa), and the Yale Peabody Museum (E. Faller) for providing samples. Discussions with D. Anderson and reviews by E. Hauri and A. Brandon are appreciated.

Author information

Authors and Affiliations


Corresponding author

Correspondence to Anders Meibom.

Ethics declarations

Competing interests

The authors declare that they have no competing financial interests.

Supplementary information

Rights and permissions

Reprints and permissions

About this article

Cite this article

Meibom, A., Sleep, N., Chamberlain, C. et al. Re–Os isotopic evidence for long-lived heterogeneity and equilibration processes in the Earth's upper mantle. Nature 419, 705–708 (2002).

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI:

This article is cited by


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing