Article | Published:

Grain boundaries as reservoirs of incompatible elements in the Earth's mantle


The concentrations and locations of elements that strongly partition into the fluid phase in rocks provide essential constraints on geochemical and geodynamical processes in Earth's interior. A fundamental question remains, however, as to where these incompatible elements reside before formation of the fluid phase. Here we show that partitioning of calcium between the grain interiors and grain boundaries of olivine in natural and synthetic olivine-rich aggregates follows a thermodynamic model for equilibrium grain-boundary segregation. The model predicts that grain boundaries can be the primary storage sites for elements with large ionic radius—that is, incompatible elements in the Earth's mantle. This observation provides a mechanism for the selective extraction of these elements and gives a framework for interpreting geochemical signatures in mantle rocks.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1

    Hiraga, T., Anderson, I. M. & Kohlstedt, D. L. Chemistry of grain boundaries in mantle rocks. Am. Mineral. 88, 1015–1019 (2003)

  2. 2

    McLean, D. Grain Boundaries in Metals 346 (Clarendon, Oxford, 1957)

  3. 3

    Menzies, M. M. & Murthy, V. R. Strontium isotope geochemistry of alpine tectonite lherzolites: Data compatible with a mantle origin. Earth Planet. Sci. Lett. 38, 346–354 (1978)

  4. 4

    Ottonello, G. Rare earth abundances and distribution in some spinel peridotite xenoliths from Assab (Ethiopia). Geochim. Cosmochim. Acta 44, 1885–1901 (1980)

  5. 5

    Fraser, D. G., Watt, F., Grime, G. W. & Takacs, J. Direct determination of strontium enrichment on grain boundaries in a garnet lherzolite xenolith by proton microprobe analysis. Nature 312, 352–354 (1984)

  6. 6

    Stosch, H.-G., Lugmair, G. W. & Kovalenko, V. I. Spinel peridotite xenoliths from the Tariat Depression, Mongolia. II: Geochemistry and Nd and Sr isotopic composition and their implications for the evolution of the subcontinental lithosphere. Geochim. Cosmochim. Acta 50, 2601–2614 (1986)

  7. 7

    Suzuki, K. Grain-boundary enrichment of incompatible elements in some mantle peridotites. Chem. Geol. 63, 319–334 (1987)

  8. 8

    Zindler, A. & Jagoutz, E. Mantle cryptology. Geochim. Cosmochim. Acta 52, 319–333 (1988)

  9. 9

    Ionov, D. A., Kramm, U. & Stosch, H.-G. Evolution of the upper mantle beneath the southern Baikal rift zone: an Sr-Nd isotope study of xenoliths from the Bartoy volcanoes. Contrib. Mineral. Petrol. 111, 235–247 (1992)

  10. 10

    Xu, X., O'Reilly, S. Y., Griffin, W. L. & Zhou, X. Enrichment of upper mantle peridotite: petrological, trace element and isotopic evidence in xenoliths from SE China. Chem. Geol. 198, 163–188 (2003)

  11. 11

    Hiraga, T., Anderson, I. M., Zimmerman, M. E., Mei, S. & Kohlstedt, D. L. Structure and chemistry of grain boundaries in deformed, olivine + basalt and partially molten lherzolite aggregates: Evidence of melt-free grain boundaries. Contrib. Mineral. Petrol. 144, 163–175 (2002)

  12. 12

    Waff, H. S. & Holdren, G. R. The nature of grain boundaries in dunite and lherzolite xenoliths: Implications for magma transport in refractory upper mantle material. J. Geophys. Res. 86, 3677–3683 (1981)

  13. 13

    Tan, B. H., Jackson, I. & Fitz Gerald, J. D. High-temperature viscoelasticity of fine-grained polycrystalline olivine. Phys. Chem. Miner. 28, 641–664 (2001)

  14. 14

    Cliff, G. & Lorimer, G. W. The quantitative analysis of thin specimens. J. Microsc. 103, 203–207 (1975)

  15. 15

    Yan, Y., Chisholm, M. F., Duscher, G. & Pennycook, S. J. Atomic structure of a Ca-doped [001] tilt grain boundary in MgO. Electron Microsc. 47, 115–120 (1998)

  16. 16

    Kingery, W. D. Plausible concepts necessary and sufficient for interpretation of ceramic grain-boundary phenomena, II. Solute segregation, grain-boundary diffusion, and general discussion. J. Am. Ceram. Soc. 57, 74–83 (1974)

  17. 17

    Beattie, P. Systematics and energetics of trace-element partitioning between olivine and silicate melts: Implications for the nature of mineral/melt partitioning. Chem. Geol. 117, 57–71 (1994)

  18. 18

    Blundy, J. & Wood, B. Prediction of crystal-melt partition coefficients from elastic moduli. Nature 372, 452–454 (1994)

  19. 19

    Brice, J. C. Some thermodynamic aspects of the growth of strained crystals. J. Cryst. Growth 28, 249–253 (1975)

  20. 20

    Isaak, D. G. High temperature elasticity of iron-bearing olivines. J. Geophys. Res. 97, 1871–1885 (1992)

  21. 21

    Takeuchi, Y., Yamanaka, T., Haga, N. & Hirana, M. in Material Science of the Earth's Interior (ed. Sunagawa, I.) 191–231 (Terra Scientific, Tokyo, 1984)

  22. 22

    Purton, J. A., Allan, N. L., Blundy, J. D. & Wasserman, E. A. Isovalent trace element partitioning between minerals and melts: A computer simulation study. Geochim. Cosmochim. Acta 60, 4977–4987 (1996)

  23. 23

    Johnson, W. C. Grain boundary segregation in ceramics. Metall. Trans. A 8A, 1413–1422 (1977)

  24. 24

    Shervais, J. Thermal emplacement model for the alpine lherzolite massif at Balmuccia (Italy). J. Petrol. 20, 795–820 (1979)

  25. 25

    German, R. M. Formation of necklace microstructures during liquid phase sintering: model calculation. Int. J. Powder Metall. 22, 31–38 (1986)

  26. 26

    Li, C.-W. & Kingery, W. D. in Advances in Ceramics (ed. Kingery, W. D.) 368–378 (American Ceramic Society, Columbus, 1985)

  27. 27

    Frey, F. A. & Printz, M. Ultramafic inclusions from San Carlos, Arizona: Petrologic and geochemical data bearing on their petrogenesis. Earth Planet. Sci. Lett. 38, 129–176 (1978)

  28. 28

    Oxburgh, E. R. Petrological evidence for the presence of amphiboles in the upper mantle and its petrogenetic and geophysical implications. Geol. Mag. 101, 1–11 (1964)

  29. 29

    Wang, W. & Takahashi, E. J. Subsolidus and melting experiments of K-doped peridotite KLB-1 to 27 GPa: Its geophysical and geochemical implications. Geophys. Res. 105, 2855–2868 (2000)

  30. 30

    Watson, E. B., Brenan, J. M. & Baker, D. R. in Continental Mantle (ed. Menzies, M.) 111–125 (Oxford Univ. Press, Oxford, 1991)

  31. 31

    Van Orman, J. A., Grove, T. L. & Shimizu, N. Uranium and thorium diffusion in diopside. Earth Planet. Sci. Lett. 160, 505–519 (1998)

  32. 32

    Hauri, E., Wagner, T. P. & Grove, T. L. Experimental and natural partitioning of Th, U, Pb and other trace elements between garnet, clinopyroxene and basaltic melts. Chem. Geol. 117, 149–166 (1994)

  33. 33

    Nakamura, M. & Watson, E. B. Experimental study of aqueous fluid infiltration into quartzite: implications for the kinetics of fluid redistribution and grain growth driven by interfacial energy reduction. Geofluids 1, 73–89 (2001)

  34. 34

    Maury, R. C., Defant, M. J. & Joron, J. L. Metasomatism of the sub-arc mantle inferred from trace elements in Philippine xenoliths. Nature 360, 661–663 (1992)

  35. 35

    Zanetti, A., Mazzucchelli, M., Rivalenti, G. & Vannucchi, R. The Finero phlogopite-peridotite massif: an example of subduction-related metasomatism. Contrib. Mineral. Petrol. 134, 107–122 (1999)

Download references


We thank M. Hirschmann and T. Morishita for discussions and M. Zimmerman for experimental assistance. T.H. acknowledges receipt of a JSPS research fellowship. This collaboration was performed under the ORNL SHaRE User Program and with support from the NSF.

Author information

Correspondence to Takehiko Hiraga.

Ethics declarations

Competing interests

The authors declare that they have no competing financial interests.

Rights and permissions

Reprints and Permissions

About this article

Further reading

Figure 1: Chemistry and structure of olivine-olivine grain boundaries in a sample of olivine + anorthite annealed at 1,473 K.
Figure 2: Calcium concentrations in olivine grain boundaries versus concentration in olivine grain matrices.
Figure 3: Ratio of solute concentration in a system composed of grain matrices + grain boundaries, CGM+GB, to that of a system composed of grain matrices alone, CGM, versus ionic radius at a temperature of 1,473 K.


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.