Abstract
The Earth's lower mantle is believed to be composed mainly of (Mg,Fe)SiO3 perovskite, with lesser amounts of (Mg,Fe)O and CaSiO3 (ref. 1). But it has not been possible to explain many unusual properties of the lowermost ∼150 km of the mantle (the D″ layer) with this mineralogy. Here, using ab initio simulations and high-pressure experiments, we show that at pressures and temperatures of the D″ layer, MgSiO3 transforms from perovskite into a layered CaIrO3-type post-perovskite phase. The elastic properties of the post-perovskite phase and its stability field explain several observed puzzling properties of the D″ layer: its seismic anisotropy2, the strongly undulating shear-wave discontinuity at its top3,4,5,6 and possibly the anticorrelation between shear and bulk sound velocities7,8.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Rent or buy this article
Prices vary by article type
from$1.95
to$39.95
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Fiquet, G. Mineral phases of the Earth's mantle. Z. Krist. 216, 248–271 (2001)
Panning, M. & Romanowicz, B. Inferences on flow at the base of Earth's mantle based on seismic anisotropy. Science 303, 351–353 (2004)
Lay, T. & Helmberger, D. V. A shear velocity discontinuity in the lower mantle. Geophys. Res. Lett. 10, 63–66 (1983)
Sidorin, I., Gurnis, M., Helmberger, D. V. & Ding, X. Interpreting D″ seismic structure using synthetic waveforms computed from dynamic models. Earth Planet. Sci. Lett. 163, 31–41 (1998)
Sidorin, I., Gurnis, M. & Helmberger, D. V. Evidence for a ubiquitous seismic discontinuity at the base of the mantle. Science 286, 1326–1331 (1999)
Sidorin, I., Gurnis, M. & Helmberger, D. V. Dynamics of a phase change at the base of the mantle consistent with seismological observations. J. Geophys. Res. 104, 15005–15023 (1999)
Su, W. J. & Dziewonski, A. M. Simultaneous inversion for 3-D variations in shear and bulk velocity in the mantle. Phys. Earth Planet. Inter. 100, 135–156 (1997)
Masters, G. et al. in Earth's Deep Interior: Mineral Physics and Tomography from the Atomic to the Global Scale (ed. Karato, S.-i.) 63–87 (AGU Geophysical Monograph 117, American Geophysical Union, Washington DC, 2000)
Saxena, S. K. et al. Stability of perovskite (MgSiO3) in the Earth's mantle. Science 274, 1357–1359 (1996)
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)
Serghiou, G., Zerr, A. & Boehler, R. (Mg,Fe)SiO3-perovskite stability under lower mantle conditions. Science 280, 2093–2095 (1998)
Shim, S. H., Duffy, T. S. & Shen, G. Y. Stability and structure of MgSiO3 perovskite to 2300-kilometer depth in Earth's mantle. Science 293, 2437–2440 (2001)
Ono, S., Ohishi, Y. & Mibe, K. Phase transition of Ca-perovskite and stability of Al-bearing Mg-perovskite in the lower mantle. Am. Mineral. (in the press)
Ono, S., Sata, N. & Ohishi, Y. Phase transformation of perovskite structure in Fe2O3 at high pressures and high temperatures. Am. Mineral. (submitted)
Rodi, F. & Babel, D. Erdalkaliiridium(IV) - oxide: Kristallstruktur von CaIrO3 . Z. Anorg. Allg. Chem. 336, 17–23 (1965)
Perdew, J. P., Burke, K. & Ernzerhof, M. Generalized gradient approximation made simple. Phys. Rev. Lett. 77, 3865–3868 (1996)
Oganov, A. R. & Brodholt, J. P. High-pressure phases in the Al2SiO5 system and the problem of Al-phase in Earth's lower mantle: ab initio pseudopotential calculations. Phys. Chem. Miner. 27, 430–439 (2000)
Baroni, S., de Gironcoli, S., Dal Corso, A. & Gianozzi, P. Phonons and related crystal properties from density-functional perturbation theory. Rev. Mod. Phys. 73, 515–562 (2001)
Urusov, V. S. Theoretical Crystal Chemistry (Moscow State Univ. Press, Moscow, 1987) [in Russian]
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)
Oganov, A. R., Brodholt, J. P. & Price, G. D. Ab initio elasticity and thermal equation of state of MgSiO3 perovskite. Earth Planet. Sci. Lett. 184, 555–560 (2001)
Ono, S., Hirose, K., Isshiki, M., Mibe, K. & Saito, Y. Equation of state of hexagonal aluminous phase of natural composition to 63 GPa at 300 K. Phys. Chem. Miner. 29, 527–531 (2002)
Jeanloz, R. & Williams, Q. The core-mantle boundary region. Rev. Mineral. 37, 241–259 (1998)
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)
Montagner, J.-P. & Nataf, H.-C. A simple method for inverting the azimuthal anisotropy of surface waves. J. Geophys. Res. 91, 511–520 (1986)
Murakami, M., Hirose, K., Kawamura, K., Sata, N. & Ohishi, Y. Post-perovskite phase transition in MgSiO3 . Science 304, 855–858 (2004)
Blöchl, P. E. Projector augmented-wave method. Phys. Rev. B 50, 17953–17979 (1994)
Kresse, G. & Joubert, D. From ultrasoft pseudopotentials to the projector augmented-wave method. Phys. Rev. B 59, 1758–1775 (1999)
Kresse, G. & Furthmüller, J. Efficiency of ab initio total-energy calculations for metals and semiconductors using a plane-wave basis set. Comp. Mater. Sci. 6, 15–50 (1996)
Gonze, X. et al. First-principles computation of materials properties: the ABINIT software project. Comp. Mater. Sci. 25, 478–492 (2002)
Acknowledgements
Calculations were performed at CSCS (Manno) and ETH Zurich. We thank P. Ulmer, A.N. Halliday, S. Goes, F. Cammarano, A.B. Thompson and P.J. Tackley for discussions, and Y. Ohishi and N. Sata for experimental support. Synchrotron radiation experiments were performed at the BL10XU, SPring-8.
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Competing interests
The authors declare that they have no competing financial interests.
Rights and permissions
About this article
Cite this article
Oganov, A., Ono, S. Theoretical and experimental evidence for a post-perovskite phase of MgSiO3 in Earth's D″ layer. Nature 430, 445–448 (2004). https://doi.org/10.1038/nature02701
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1038/nature02701
This article is cited by
-
Materials under extreme conditions using large X-ray facilities
Nature Reviews Methods Primers (2023)
-
Crystal structure prediction at finite temperatures
npj Computational Materials (2023)
-
Progress in the numerical modeling of mantle plumes
Science China Earth Sciences (2023)
-
Melting and density of MgSiO3 determined by shock compression of bridgmanite to 1254GPa
Nature Communications (2021)
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.