Skip to main content

Thank you for visiting nature.com. 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.

Upside-down differentiation and generation of a ‘primordial’ lower mantle

Abstract

Except for the first 50–100 million years or so of the Earth’s history, when most of the mantle may have been subjected to melting, the differentiation of Earth’s silicate mantle has been controlled by solid-state convection1. As the mantle upwells and decompresses across its solidus, it partially melts. These low-density melts rise to the surface and form the continental and oceanic crusts, driving the differentiation of the silicate part of the Earth. Because many trace elements, such as heat-producing U, Th and K, as well as the noble gases, preferentially partition into melts (here referred to as incompatible elements), melt extraction concentrates these elements into the crust (or atmosphere in the case of noble gases), where nearly half of the Earth’s budget of these elements now resides2. In contrast, the upper mantle, as sampled by mid-ocean ridge basalts, is highly depleted in incompatible elements, suggesting a complementary relationship with the crust. Mass balance arguments require that the other half of these incompatible elements be hidden in the Earth’s interior. Hypotheses abound for the origin of this hidden reservoir3,4,5,6. The most widely held view has been that this hidden reservoir represents primordial material never processed by melting or degassing. Here, we suggest that a necessary by-product of whole-mantle convection during the Earth’s first billion years is deep and hot melting, resulting in the generation of dense liquids that crystallized and sank into the lower mantle. These sunken lithologies would have ‘primordial’ chemical signatures despite a non-primordial origin.

Your institute does not have access to this article

Relevant articles

Open Access articles citing this article.

Access options

Buy article

Get time limited or full article access on ReadCube.

$32.00

All prices are NET prices.

Figure 1: Conditions for dense melt generation.
Figure 2: Melting in the Archaean and modern mantle.
Figure 3: Generation of ‘primordial’, undegassed lower mantle.
Figure 4: Geophysical properties of Fe-rich chemical boundary layer.

References

  1. Abe, Y. Thermal and chemical evolution of the terrestrial magma ocean. Phys. Earth Planet. Inter. 100, 27–39 (1997)

    ADS  CAS  Article  Google Scholar 

  2. 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)

    ADS  CAS  Article  Google Scholar 

  3. Kellogg, L. H., Hager, B. H. & van der Hilst, R. D. Compositional stratification in the deep mantle. Science 283, 1881–1884 (1999)

    ADS  CAS  Article  Google Scholar 

  4. Becker, T. W., Kellog, J. B. & O'Connell, R. J. Thermal constraints on the survival of primitive blobs in the lower mantle. Earth Planet. Sci. Lett. 171, 351–365 (1999)

    ADS  CAS  Article  Google Scholar 

  5. Tackley, P. J. Self-consistent generation of tectonic plates in three-dimensional mantle convection. Earth Planet. Sci. Lett. 157, 9–22 (1998)

    ADS  CAS  Article  Google Scholar 

  6. Class, C. & Goldstein, S. L. Evolution of helium isotopes in the Earth’s mantle. Nature 436, 1107–1112 (2005)

    ADS  CAS  Article  Google Scholar 

  7. Kurz, M. D., Jenkins, W. J. & Hart, S. R. Helium isotopic systematics of ocean islands and mantle heterogeneity. Nature 297, 43–46 (1982)

    ADS  CAS  Article  Google Scholar 

  8. Graham, D. W. Noble gas isotope geochemistry of mid-ocean ridge and ocean island basalts: characterization of mantle source reservoirs. Rev. Mineral. 47, 247–317 (2002)

    CAS  Article  Google Scholar 

  9. van der Hilst, R., Widiyantoro, S. & Engdahl, E. R. Evidence for deep mantle circulation from global tomography. Nature 386, 578–584 (1997)

    ADS  CAS  Article  Google Scholar 

  10. Boyet, M. & Carlson, R. W. 142Nd evidence for early (>4.53) global differentiation of the silicate Earth. Science 309, 576–581 (2005)

    ADS  CAS  Article  Google Scholar 

  11. Stixrude, L., de Koker, N., Sun, N., Mookherjee, M. & Karki, B. B. Thermodynamics of silicate liquids in the deep Earth. Earth Planet. Sci. Lett. 278, 226–232 (2009)

    ADS  CAS  Article  Google Scholar 

  12. Christensen, U. R. & Hofmann, A. W. Segregation of subducted oceanic crust in the convecting mantle. J. Geophys. Res. 99, 19867–19884 (1994)

    ADS  CAS  Article  Google Scholar 

  13. Miller, G. H., Stolper, E. M. & Ahrens, T. J. The equation of state of a molten komatiite. 2. Application to komatiite petrogenesis and the Hadean mantle. J. Geophys. Res. 96, 11849–11864 (1991)

    ADS  Article  Google Scholar 

  14. Stolper, E., Walker, D., Hager, B. H. & Hays, J. F. Melt segregation from partially molten source regions: the importance of melt density and source region size. J. Geophys. Res. 86, 6261–6271 (1981)

    ADS  CAS  Article  Google Scholar 

  15. Suzuki, A., Ohtani, E. & Kato, T. Density and thermal expansion of a peridotite melt at high pressure. Phys. Earth Planet. Inter. 107, 53–61 (1998)

    ADS  CAS  Article  Google Scholar 

  16. Herzberg, C. & Zhang, J. Melting experiments on anhydrous peridotite KLB-1: compositions of magmas in the upper mantle and transition zone. J. Geophys. Res. 101, 8271–8295 (1996)

    ADS  CAS  Article  Google Scholar 

  17. Lange, R. A. & Carmichael, I. S. E. Densities of Na2O-K2O-CaO-MgO-FeO-Fe2O3-Al2O3-TiO2-SiO2 liquids: new measurements and derived partial molar properties. Geochim. Cosmochim. Acta 51, 2931–2946 (1987)

    ADS  CAS  Article  Google Scholar 

  18. Ohtani, E. & Maeda, M. Density of basaltic melt at high pressure and stability of the melt at the base of the lower mantle. Earth Planet. Sci. Lett. 193, 69–75 (2001)

    ADS  CAS  Article  Google Scholar 

  19. Dziewonski, A. & Anderson, D. L. Preliminary reference earth model. Phys. Earth Planet. Inter. 25, 297–356 (1981)

    ADS  Article  Google Scholar 

  20. Tronnes, R. G. & Frost, D. J. Peridotite melting and mineral-melt partitioning of major and minor elements at 22–24.5 GPa. Earth Planet. Sci. Lett. 197, 117–131 (2002)

    ADS  CAS  Article  Google Scholar 

  21. Putirka, K. D., Perfit, M., Ryerson, F. J. & Jackson, M. G. Ambient and excess mantle temperatures, olivine thermometry, and active vs. passive upwelling. Chem. Geol. 241, 177–206 (2007)

    ADS  CAS  Article  Google Scholar 

  22. Lee, C.-T. A., Luffi, P., Plank, T., Dalton, H. A. & Leeman, W. P. Constraints on the depths and temperatures of basaltic magma generation on Earth and other terrestrial planets using new thermobarometers for mafic magmas. Earth Planet. Sci. Lett. 279, 20–33 (2009)

    ADS  CAS  Article  Google Scholar 

  23. Richter, F. M. Models for the Archean thermal regime. Earth Planet. Sci. Lett. 73, 350–360 (1985)

    ADS  CAS  Article  Google Scholar 

  24. Korenaga, J. Urey ratio and the structure and evolution of Earth’s mantle. Rev. Geophys. 46 10.1029/2007RG000241 (2008)

  25. Labrosse, S. & Jaupart, C. Thermal evolution of the Earth: secular changes and fluctuations of plate characteristics. Earth Planet. Sci. Lett. 260, 465–481 (2007)

    ADS  CAS  Article  Google Scholar 

  26. Hart, S. R., Hauri, E. H., Oschmann, L. A. & Whitehead, J. A. Mantle plumes and entrainment: isotopic evidence. Science 256, 517–520 (1992)

    ADS  CAS  Article  Google Scholar 

  27. Hernlund, J. W. & Houser, C. On the distribution of seismic velocities in Earth’s deep mantle. Earth Planet. Sci. Lett. 265, 423–437 (2008)

    ADS  CAS  Article  Google Scholar 

  28. Mattern, E., Matas, J., Ricard, Y. & Bass, J. Lower mantle composition and temperature from mineral physics and thermodynamic modelling. Geophys. J. Int. 160, 973–990 (2005)

    ADS  CAS  Article  Google Scholar 

  29. Stixrude, L. & Lithgow-Bertelloni, C. Thermodynamics of mantle minerals—I. Physical properties. Geophys. J. Int. 162, 610–632 (2005)

    ADS  Article  Google Scholar 

  30. Ishii, M. & Tromp, J. Even-degree lateral variations in the Earth’s mantle constrained by free oscillations and the free-air gravity anomaly. Geophys. J. Int. 145, 77–96 (2001)

    ADS  Article  Google Scholar 

  31. Li, L. et al. Elasticity of CaSiO3 perovskite at high pressure and high temperature. Phys. Earth Planet. Inter. 155, 249–259 (2006)

    ADS  CAS  Article  Google Scholar 

  32. 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)

    ADS  CAS  Article  Google Scholar 

  33. Berry, A. J., Danyushevsky, L. V., O’Neill, H. S. C., Newville, M. & Sutton, S. R. Oxidation state of iron in komatiitic melt inclusions indicates hot Archaean mantle. Nature 455, 960–964 (2008)

    ADS  CAS  Article  Google Scholar 

  34. Langmuir, C., Klein, E. M. & Plank, T. eds. Petrological Systematics of Mid-Ocean Ridge Basalts: Constraints on Melt Generation Beneath Ocean Ridges (American Geophysical Union, 1992)

    Google Scholar 

  35. Arndt, N. T. Komatiites, kimberlites and boninites. J. Geophys. Res. 108 10.1029/2002JB002157 (2003)

  36. Grove, T. L. & Parman, S. W. Thermal evolution of the Earth as recorded by komatiites. Earth Planet. Sci. Lett. 219, 173–187 (2004)

    ADS  CAS  Article  Google Scholar 

  37. Bina, C. R. & Helffrich, G. R. Calculation of elastic properties from thermodynamic equation of state principles. Annu. Rev. Earth Planet. Sci. 20, 527–552 (1992)

    ADS  Article  Google Scholar 

  38. Ohtani, E., Kawabe, I., Moriyama, J. & Nagata, Y. Partitioning of elements between majorite garnet and melt implications for petrogenesis of komatiite. Contrib. Mineral. Petrol. 103, 263–269 (1989)

    ADS  CAS  Article  Google Scholar 

  39. Sakamaki, T., Suzuki, A. & Ohtani, E. Stability of hydrous melt at the base of the Earth’s upper mantle. Nature 439, 192–194 (2006)

    ADS  CAS  Article  Google Scholar 

  40. Agee, C. B. Static compression of hydrous silicate melt and the effect of water on planetary differentiation. Earth Planet. Sci. Lett. 265, 641–654 (2008)

    ADS  CAS  Article  Google Scholar 

  41. Connolly, J. A. D. & Petrini, K. An automated strategy for calculation of phase diagram sections and retrieval of rock properties as a function of physical conditions. J. Metamorph. Geol. 20, 697–708 (2002)

    ADS  Article  Google Scholar 

Download references

Acknowledgements

The ideas for this paper were conceived at Rice University and fine-tuned at the 2008 Cooperative Institute for Deep Earth Research workshop at the Kavli Institute. We thank G. Masters, M. Ishii, M. Manga, M. Jellinek, B. Romanowicz, T. Plank, H. Gonnermann, L. Stixrude and C. Lithgow-Bertelloni for discussions and S. Parman for reviews. G. Masters also helped with velocity calculations. We thank the Packard Foundation and the NSF for support. J. Li also acknowledges support from the University of Illinois.

Author Contributions C.-T.A.L. planned the paper, performed the modelling and wrote the paper; P.L. helped with the modelling and interpretation and figures; T.H. helped with the geodynamic interpretation; J.L. helped with the density modelling and interpretation; R.D. helped with the petrologic and geochemical interpretations; and J.H. helped with the geodynamic and mineral physics interpretations.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Cin-Ty A. Lee.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

PowerPoint slides

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Lee, CT., Luffi, P., Höink, T. et al. Upside-down differentiation and generation of a ‘primordial’ lower mantle. Nature 463, 930–933 (2010). https://doi.org/10.1038/nature08824

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature08824

Further reading

Comments

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.

Search

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