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The elasticity of the MgSiO3 post-perovskite phase in the Earth's lowermost mantle

Abstract

MgSiO3 perovskite has been assumed to be the dominant component of the Earth's lower mantle, although this phase alone cannot explain the discontinuity in seismic velocities observed 200–300 km above the core–mantle boundary (the D″ discontinuity) or the polarization anisotropy observed in the lowermost mantle1. Experimental and theoretical studies that have attempted to attribute these phenomena to a phase transition in the perovskite phase have tended to simply confirm the stability of the perovskite phase2,3,4,5,6. However, recent in situ X-ray diffraction measurements have revealed7 a transition to a ‘post-perovskite’ phase above 125 GPa and 2,500 K—conditions close to those at the D″ discontinuity. Here we show the results of first-principles calculations of the structure, stability and elasticity of both phases at zero temperature. We find that the post-perovskite phase becomes the stable phase above 98 GPa, and may be responsible for the observed seismic discontinuity and anisotropy in the lowermost mantle. Although our ground-state calculations of the unit cell do not include the effects of temperature and minor elements, they do provide a consistent explanation for a number of properties of the D″ layer.

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Figure 1: The unit cell structures of MgSiO3.
Figure 2: The enthalpy difference between the perovskite phase and post-perovskite phase as a function of pressure.
Figure 3: The variation of compressional (vP) and shear (vS) wave velocities as a function of propagation direction.

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References

  1. Poirier, J. P. Introduction to the Physics of the Earth's Interior (Cambridge Univ. Press, Cambridge, 2000)

    Book  Google Scholar 

  2. Fiquet, G., Dewaele, A., Andrault, D., Kunz, M. & Le Bihan, T. Thermoelastic properties and crystal structure of MgSiO3 perovskite at lower mantle pressure and temperature conditions. Geophys. Res. Lett. 27, 21–24 (2000)

    Article  ADS  CAS  Google Scholar 

  3. Andrault, D. Evaluation of (Mg, Fe) partitioning between silicate perovskite and magnesiowustite up to 120 GPa and 2300 K. J. Geophys. Res. 106, 2079–2087 (2001)

    Article  ADS  CAS  Google Scholar 

  4. Stixrude, L. & Cohen, R. E. Stability of orthorhombic MgSiO3 perovskite in the Earth's lower mantle. Nature 364, 613–616 (1993)

    Article  ADS  CAS  Google Scholar 

  5. Wentzcovitch, R. M., Ross, N. L. & Price, G. D. Ab initio study of MgSiO3 and CaSiO3 perovskites at lower-mantle pressures. Phys. Earth Planet. Inter. 90, 101–112 (1995)

    Article  ADS  CAS  Google Scholar 

  6. Warren, M. C., Ackland, G. J., Karki, B. B. & Clark, S. J. Phase transitions in silicate perovskites from first principles. Mineral. Mag. 62, 585–598 (1998)

    Article  CAS  Google Scholar 

  7. Murakami, M., Hirose, K., Kawamura, K., Sata, N. & Ohishi, Y. Post-perovskite phase transition in MgSiO3 . Science 304, 855–858 (2004)

    Article  ADS  CAS  Google Scholar 

  8. Noel, H. & Padiou, J. Structure crystalline de FeUS3 . Acta Crystallogr. B 32, 1593–1595 (1976)

    Article  Google Scholar 

  9. Narducci, A. A. & Ibers, J. A. The related compounds MThTe3(M = Mn, Mg) and ACuThSe3(A = K, Cs): Syntheses and characterization. Inorg. Chem. 39, 688–691 (2000)

    Article  CAS  Google Scholar 

  10. Ijjaali, I., Mitchell, K., Huang, F. Q. & Ibers, J. A. Syntheses and characterization of the actinide manganese selenides ThMnSe3 and UMnSe3 . J. Solid State Chem. 177, 257–261 (2004)

    Article  ADS  CAS  Google Scholar 

  11. Karki, B. B. et al. Structure and elasticity of MgO at high pressure. Am. Mineral. 82, 51–60 (1997)

    Article  ADS  CAS  Google Scholar 

  12. Karki, B. B. et al. Elastic properties of orthorhombic MgSiO3 perovskite at lower mantle pressures. Am. Mineral. 82, 635–638 (1997)

    Article  ADS  CAS  Google Scholar 

  13. Wysession, M. E., et al. in The Core-Mantle Boundary Region (eds Gurnis, M., Wysession, M. E., Knittle, E. & Buffett, B. A.) 273–297 (American Geophysical Union, Washington DC, 1998)

    Book  Google Scholar 

  14. Sidorin, I., Gurnis, M. & Helmberger, D. V. Evidence for a ubiquitous seismic discontinuity at the base of the mantle. Science 286, 1326–1331 (1999)

    Article  CAS  Google Scholar 

  15. Lay, T., Williams, Q., Garnero, E. J., Kellogg, L. & Wysession, M. E. in The Core-Mantle Boundary Region (eds Gurnis, M., Wysession, M. E., Knittle, E. & Buffett, B. A.) 299–318 (American Geophysical Union, Washington DC, 1998)

    Book  Google Scholar 

  16. Panning, M. & Romanowicz, B. Inferences on flow at the base of Earth's mantle based on seismic anisotropy. Science 303, 351–353 (2004)

    Article  ADS  CAS  Google Scholar 

  17. Montagner, J. P. & Nataf, H. C. A simple method for inverting the azimuthal anisotropy of surface waves. J. Geophys. Res. 91, 511–520 (1986)

    Article  ADS  Google Scholar 

  18. Wentzcovitch, R. M., Karki, B. B., Karato, S. & Da Silva, C. R. S. High pressure elastic anisotropy of MgSiO3 perovskite and geophysical implications. Earth Planet. Sci. Lett. 164, 371–378 (1998)

    Article  ADS  CAS  Google Scholar 

  19. Karato, S., Zhang, S. & Wenk, H. R. Superplasticity in Earth's lower mantle: evidence from seismic anisotropy and rock physics. Science 270, 458–461 (1995)

    Article  ADS  CAS  Google Scholar 

  20. Masters, G. & Laske, G. in Earth's Deep Interior: Mineral Physics and Tomography from the Atomic to the Global Scale (eds Karato, S., Forte, A., Liebermann, R., Masters, G. & Stixrude, L.) 63–87 (American Geophysical Union, Washington DC, 2000)

    Book  Google Scholar 

  21. Oganov, A. R., Brodholt, J. P. & Price, G. D. The elastic constants of MgSiO3 perovskite at pressures and temperatures of the Earth's mantle. Nature 411, 934–937 (2001)

    Article  ADS  CAS  Google Scholar 

  22. Wentzcovitch, R. M., Karki, B. B., Cococcioni, M. & de Gironcoli, S. Thermoelastic properties of MgSiO3-perovskite: insights on the nature of the Earth's lower mantle. Phys. Rev. Lett. 92, 018501 (2004)

    Article  ADS  CAS  Google Scholar 

  23. Murakami, M. Phase Transition of Lower Mantle Mineral and its Geophysical Implications Thesis, Tokyo Institute of Technology (2004)

    Google Scholar 

  24. Vanderbilt, D. Soft self-consistent pseudopotentials in a generalized eigenvalue formalism. Phys. Rev. B 41, 7892–7895 (1990)

    Article  ADS  CAS  Google Scholar 

  25. Civalleri, B. & Harrison, N. M. New ultrasoft pseudopotentials for the study of silicates. Mol. Simulat. 28, 213–237 (2002)

    Article  CAS  Google Scholar 

  26. Brodholt, J. P., Organov, A. R. & Price, G. D. Computational mineral physics and the physical properties of perovskite. Phil. Trans. R. Soc. Lond. A 360, 2507–2520 (2002)

    Article  ADS  CAS  Google Scholar 

  27. Monkhorst, H. J. & Pack, J. D. Special points for Brillouin-zone integrations. Phys. Rev. B 13, 5188–5192 (1976)

    Article  ADS  MathSciNet  Google Scholar 

  28. Nielsen, O. H. & Martin, R. M. First principles calculation of stress. Phys. Rev. Lett. 50, 697–700 (1983)

    Article  ADS  CAS  Google Scholar 

  29. Francis, G. P. & Payne, M. C. Finite basis set corrections to total energy pseudopotential calculations. J. Phys. Condens. Matter 2, 4395–4404 (1990)

    Article  ADS  Google Scholar 

  30. Iitaka, T. & Ebisuzaki, T. First-principles calculation of elastic properties of solid argon at high pressures. Phys. Rev. B 65, 012103 (2002)

    Article  ADS  Google Scholar 

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Acknowledgements

We thank S. Kaneshima for discussions, D.M. Bird for providing CASTEP codes, N.M. Harrison for pseudopotentials and the computer centres of RIKEN and NIG for access to the supercomputers. This work was also supported by JASRI/SPring-8 and IFREE/JAMSTEC.

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Correspondence to T. Iitaka.

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Supplementary Figure

The anisotropic compressibility of the PP-phase. (DOC 73 kb)

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Iitaka, T., Hirose, K., Kawamura, K. et al. The elasticity of the MgSiO3 post-perovskite phase in the Earth's lowermost mantle. Nature 430, 442–445 (2004). https://doi.org/10.1038/nature02702

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