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.

Highly unradiogenic lead isotope ratios from the Horoman peridotite in Japan


Basalts at mid-ocean ridges are generated by partial melting of the Earth’s upper mantle. As a result of this process, the upper mantle has become depleted over time in elements that are preferentially removed by melting1,2,3. Although mid-ocean-ridge basalts have traditionally been thought to reflect the chemical composition of such depleted mantle2,3,4,5,6,7, recent work has revealed the existence of domains in the upper mantle that are apparently not sampled by the basalts8. Here we present the lead (Pb), neodymium (Nd) and hafnium (Hf) isotope compositions of peridotites from the Horoman orogenic massif in Japan, which is considered to represent the residues of melting of the upper mantle. These peridotites exhibit the lowest Pb isotope ratios reported from any known mantle material, along with high Nd and Hf isotope ratios. These data suggest that chemical depletion of the peridotites occurred around a billion years ago, and that they represent ancient mantle domains that have escaped convective stirring and homogenization. We suggest that such domains—if abundant in the mantle—may constitute a hitherto unrecognized reservoir with highly unradiogenic lead.

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

Relevant articles

Open Access articles citing this article.

Access options

Rent or buy this article

Prices vary by article type



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

Figure 1: Primitive-mantle-normalized23 trace-element patterns.
Figure 2: Pb, Nd and Hf isotope composition of the Horoman peridotites.
Figure 3: Initial isotopic compositions at 1 Gyr and Pb isotope mass balance of the bulk silicate Earth.


  1. Hofmann, A. W. Chemical differentiation of the Earth: The relationship between mantle, continental crust, and oceanic crust. Earth Planet. Sci. Lett. 90, 297–314 (1988).

    Article  Google Scholar 

  2. Workman, R. K. & Hart, S. R. Major and trace element composition of the depleted MORB mantle (DMM). Earth Planet. Sci. Lett. 231, 53–72 (2005).

    Article  Google Scholar 

  3. Salters, J. M. & Strecke, A. Composition of the depleted mantle. Geochem. Geophys. Geosyst. 5, 10.1029/2003GC000597 (2004).

  4. Hart, S. R. Heterogeneous mantle domains: signatures, genesis and mixing chronologies. Earth Planet. Sci. Lett. 90, 273–296 (1988).

    Article  Google Scholar 

  5. White, W. M. Sources of oceanic basalts: Radiogenic isotope evidence. Geology 13, 115–118 (1985).

    Article  Google Scholar 

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

    Article  Google Scholar 

  7. Hofmann, A. W. in The Mantle & Core (ed. Carlson, R. W.) 61–101 (Vol. 2 of Treatise in Geochem, Elsevier–Pergamon, 2003).

    Google Scholar 

  8. Liu, C-Z. et al. Ancient, highly heterogeneous mantle beneath Gakkel Ridge, Arctic Ocean. Nature 452, 311–316 (2008).

    Article  Google Scholar 

  9. Barling, J. & Goldstein, S. L. Extreme isotopic variations in Heard Island lavas and the nature of mantle reservoirs. Nature 348, 59–62 (1990).

    Article  Google Scholar 

  10. Dupré, B. & Allègre, C. J. Pb–Sr isotope variation in Indian Ocean basalts and mixing phenomena. Nature 303, 142–146 (1983).

    Article  Google Scholar 

  11. Hart, S. R. A large-scale isotope anomaly in the southern hemisphere mantle. Nature 309, 753–757 (1984).

    Article  Google Scholar 

  12. Hamelin, B. & Allègre, C. J. Lead isotope study of orogenic lherzolite massifs. Earth Planet. Sci. Lett. 91, 117–131 (1988).

    Article  Google Scholar 

  13. Andres, M., Blichert-Toft, J. & Schilling, J.-G. Nature of the depleted upper mantle beneath the Atlantic: Evidence from normal mid-ocean ridge basalts from 79 N to 55. Earth Planet. Sci. Lett. 225, 89–103 (2004).

    Article  Google Scholar 

  14. Niida, K. Petrology of the Horoman ultramafic rocks. J. Fac. Sci. Hokkaido Univ. 21, 61–81 (1984).

    Google Scholar 

  15. Takahashi, N. Evidence for melt segregation towards fractures in the Horoman mantle peridotite complex. Nature 359, 52–55 (1992).

    Article  Google Scholar 

  16. Takazawa, E., Frey, F., Shimizu, N., Obata, M. & Bodinier, J. L. Geochemical evidence for melt migration and reaction in the upper mantle. Nature 359, 55–58 (1992).

    Article  Google Scholar 

  17. Yoshikawa, M. & Nakamura, E. Geochemical evolution of the Horoman peridotite complex: Implications for melt extraction, metasomatism and compositional layering in the mantle. J. Geophys. Res. 105, 2879–2901 (2000).

    Article  Google Scholar 

  18. Saal, A. E., Takazawa, E., Frey, F. A., Shimizu, N. & Hart, S. R. Re–Os isotopes in the Horoman peridotite: Evidence for refertilization? J. Petrol. 42, 25–37 (2001).

    Article  Google Scholar 

  19. Shimizu, N., Warren, J. M., Frey, F. A. & Takazawa, E. The Horoman peridotite massif: An example of ancient ultraslow-spreading ridge abyssal peridotites? EOS Trans. 87, AGU fall meeting V12C07S (2006).

  20. Plank, T. & Langumuir, C. H. The chemical composition of subducting sediments and its consequences for the crust and mantle. Chem. Geol. 145, 325–394 (1998).

    Article  Google Scholar 

  21. Kelemen, P. B., Kikawa, E., Miller, D.J & Shipboard Scientific Party, Leg 209 Summary: Processes in a 20-km-thick conductive boundary layer beneath the Mid-Atlantic Ridge, 14–16 N. Proc. Ocean Drilling Program, Scientific Results 209, 1–33 (2007).

    Google Scholar 

  22. 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  Google Scholar 

  23. McDonough, W. F. & Sun, S. S. The composition of the Earth. Chem. Geol. 120, 223–253 (1995).

    Article  Google Scholar 

  24. Stracke, A, Bizimiz, M. & Salters, V. J. M. Recycling oceanic crust: Quantitative constraints. Geochem. Geophys. Geosyst. 4, 10.1029/2001GC000223 (2003).

  25. Hart, S. R. & Staudigel, H. in Crust/Mantle Recycling at Convergent Zones (eds Hart, S. R. & Gulen, L.) 15–28 (Kluwer–Academic, 1989).

    Book  Google Scholar 

  26. Chauvel, C., Hofmann, A. W. & Vidal, P. HIMU-EM: The French-Polynesian connection. Earth Planet. Sci. Lett. 110, 99–119 (1992).

    Article  Google Scholar 

  27. Rekhämper, M. & Hofmann, A. W. Recycled ocean crust and sediment in Indian Ocean MORB. Earth Planet. Sci. Lett. 147, 93–106 (1997).

    Article  Google Scholar 

  28. Hauri, E. H. & Hart, S. R. Re–Os Isotope systematics of HIMU and EMII oceanic island basalts from the South-Pacific Ocean. Earth Planet. Sci. Lett. 114, 353–371 (1993).

    Article  Google Scholar 

Download references


We thank T. Moriguti, K. Kobayashi, T. Yokoyama and other colleagues for discussion and analytical help. K. Ozawa, K. Kunugiza, T. Usui and T. Moriyama are acknowledged for help in collecting samples. R. Tanaka and C. Sakaguchi are thanked for help in X-ray fluorescence and Sm–Nd analysis respectively. We are grateful to B. Mysen and K. Yamashita for improving the manuscript and A. W. Hofmann and F. Frey for constructive comments. This study was supported by the programme of the ‘Centre of Excellence for the 21st Century in Japan’ from MEXT to E.N. and Grants-in-aid from JSPS to A.M.

Author information

Authors and Affiliations



E.N. initiated and formulated this project. S.P.K.M. carried out the project and wrote the paper as part of his PhD thesis. All authors contributed to analysis of the samples and interpretation of the results.

Corresponding authors

Correspondence to Sanjeewa P. K. Malaviarachchi or Eizo Nakamura.

Supplementary information

Supplementary Information, Fig. S1

Supplementary Information (PDF 284 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Malaviarachchi, S., Makishima, A., Tanimoto, M. et al. Highly unradiogenic lead isotope ratios from the Horoman peridotite in Japan. Nature Geosci 1, 859–863 (2008).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

This article is cited by


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