The determination of the chemical composition of Earth’s lower mantle is a long-standing challenge in earth science. Accurate knowledge of sound velocities in the lower-mantle minerals under relevant high-pressure, high-temperature conditions is essential in constraining the mineralogy and chemical composition using seismological observations1, but previous acoustic measurements were limited to a range of low pressures and temperatures. Here we determine the shear-wave velocities for silicate perovskite and ferropericlase under the pressure and temperature conditions of the deep lower mantle using Brillouin scattering spectroscopy2. The mineralogical model that provides the best fit to a global seismic velocity profile1 indicates that perovskite constitutes more than 93 per cent by volume of the lower mantle, which is a much higher proportion than that predicted by the conventional peridotitic mantle model. It suggests that the lower mantle is enriched in silicon relative to the upper mantle, which is consistent with the chondritic Earth model. Such chemical stratification implies layered-mantle convection with limited mass transport between the upper and the lower mantle.
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Dziewonski, A. M. & Anderson, D. L. Preliminary reference Earth model. Phys. Earth Planet. Inter. 25, 297–356 (1981)
Murakami, M. et al. Development of in-situ Brillouin spectroscopy at high pressure and temperature with synchrotron radiation and infrared laser heating system: application to the Earth’s deep interior. Phys. Earth Planet. Inter. 174, 282–291 (2009)
Ringwood, A. E. Composition and Petrology of the Earth’s Mantle (McGraw Hill, 1975)
Sun, S. S. Chemical-composition and origin of the Earth’s primitive mantle. Geochim. Cosmochim. Acta 46, 179–192 (1982)
Ito, E. & Takahashi, E. Postspinel transformations in the system Mg2SiO4-Fe2SiO4 and some geophysical implications. J. Geophys. Res. 94, 10637–10646 (1989)
Allègre, C. J., Poirier, J. P., Humler, E. & Hofmann, A. W. The chemical composition of the earth. Earth Planet. Sci. Lett. 134, 515–526 (1995)
Tonks, W. B. & Melosh, H. J. Magma ocean formation due to giant impact. J. Geophys. Res. 98, 5319–5333 (1993)
Ringwood, A. E. Significance of the terrestrial Mg/Si ratio. Earth Planet. Sci. Lett. 95, 1–7 (1989)
Fei, Y. et al. Spin transition and equations of state of (Mg, Fe)O solid solutions. Geophys. Res. Lett. 34, L17307 (2007)
Ricolleau, A. et al. Density profile of pyrolite under the lower mantle conditions. Geophys. Res. Lett. 36, L06302 (2009)
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)
Murakami, M., Sinogeikin, S. V., Hellwig, H., Bass, J. D. & Li, J. Sound velocity of MgSiO3 perovskite to Mbar pressure. Earth Planet. Sci. Lett. 256, 47–54 (2007)
Murakami, M. et al. Sound velocity of MgSiO3 post-perovskite phase: a constraint on the D′′ discontinuity. Earth Planet. Sci. Lett. 259, 18–23 (2007)
Murakami, M., Ohishi, Y., Hirao, N. & Hirose, K. Elasticity of MgO to 130GPa: implications for lower mantle mineralogy. Earth Planet. Sci. Lett. 277, 123–129 (2009)
Brodholt, J. P. Pressure-induced changes in the compression mechanism of aluminous perovskite in the Earth’s mantle. Nature 407, 620–622 (2000)
Jackson, J. M., Zhang, J. & Bass, J. D. Sound velocities and elasticity of aluminous MgSiO3 perovskite: implications for aluminum heterogeneity in Earth’s lower mantle. Geophys. Res. Lett. 31, L10614 (2004)
Jackson, J. M., Zhang, J., Shu, J., Sinogeikin, S. V. & Bass, J. D. High-pressure sound velocities and elasticity of aluminous MgSiO3 perovskite to 45 GPa: implications for lateral heterogeneity in Earth’s lower mantle. Geophys. Res. Lett. 32, L21305 (2005)
Badro, J. et al. Iron partitioning in Earth’s mantle: toward a deep lower mantle discontinuity. Science 300, 789–791 (2003)
Crowhurst, J. C., Brown, J. M., Goncharov, A. F. & Jacobsen, S. D. Elasticity of (Mg,Fe)O through the spin transition of iron in the lower mantle. Science 319, 451–453 (2008)
Marquardt, H., Speziale, S., Reichmann, H. J., Frost, D. J. & Schilling, F. R. Single-crystal elasticity of (Mg0. 9Fe0. 1)O to 81 GPa. Earth Planet. Sci. Lett. 287, 345–352 (2009)
Stixrude, L. & Lithgow-Bertelloni, C. Thermodynamics of mantle minerals - I. Physical properties. Geophys. J. Int. 162, 610–632 (2005)
Kennett, B. L. N. & Jackson, I. Optimal equations of state for mantle minerals from simultaneous non-linear inversion of multiple datasets. Phys. Earth Planet. Inter. 176, 98–108 (2009)
Jackson, J. M. et al. Single-crystal elasticity and sound velocities of (Mg0. 94Fe0. 06)O ferropericlase to 20 GPa. J. Geophys. Res. 111, B09203 (2006)
Jacobsen, S. D. et al. Structure and elasticity of single-crystal (Mg,Fe)O and a new method of generating shear waves for gigahertz ultrasonic interferometry. J. Geophys. Res. 107, 2037 (2002)
Kung, J., Li, B. S., Weidner, D. J., Zhang, J. Z. & Liebermann, R. C. Elasticity of (Mg0. 83,Fe0. 17)O ferropericlase at high pressure: ultrasonic measurements in conjunction with X-radiation techniques. Earth Planet. Sci. Lett. 203, 557–566 (2002)
Jackson, I. & Rigden, S. M. in The Earth’s Mantle: Composition, Structure and Evolution (ed. Jackson, I. ) 405–460 (Cambridge Univ. Press, 1998)
Brown, J. M. & Shankland, T. J. Thermodynamic parameters in the Earth as determined from seismic profiles. Geophys. J. R. Astron. Soc. 66, 579–596 (1981)
Anderson, O. L. The Earth’s core and the phase-diagram of iron. Phil. Trans. R. Soc. Lond.. A 306, 21–35 (1982)
Li, L. et al. Elasticity of CaSiO3 perovskite at high pressure and high temperature. Earth Planet. Sci. Lett. 155, 249–259 (2006)
Stixrude, L., Lithgow-Bertelloni, C., Kiefer, B. & Fumagalli, P. Phase stability and softening in CaSiO3 perovskite at high pressure. Phys. Rev. B 75, 024108 (2007)
Christensen, U. R. & Yuen, D. A. Layered convection induced by phase-transitions. J. Geophys. Res. 90, 10291–10300 (1985)
van der Hist, R., Engdahl, R., Spakman, W. & Nolet, G. Tomographic imaging of subducted lithosphere below northwest Pacific island arcs. Nature 353, 37–43 (1991)
Tange, Y., Nishihara, Y. & Tsuchiya, T. Unified analyses for P-V-T equation of state of MgO: a solution for pressure-scale problems in high P-T experiments. J. Geophys. Res. 115, B12203 (2010)
Murakami, M., Hirose, K., Kawamura, K., Sata, N. & Ohishi, Y. Post-perovskite phase transition in MgSiO3 . Science 304, 855–858 (2004)
Akahama, Y. & Kawamura, H. High-pressure Raman spectroscopy of diamond anvils to 250 GPa: method for pressure determination in the multimegabar pressure range. J. Appl. Phys. 96, 3748–3751 (2004)
Sata, N., Shen, G., Rivers, M. L. & Sutton, S. R. Pressure-volume equation of state of the high-pressure B2 phase of NaCl. Phys. Rev. B 65, 104114 (2002)
Holmes, N. C., Moriarty, J. A., Gathers, G. R. & Nellis, W. J. The equation of state of platinum to 660 GPa (6.6Mbar). J. Appl. Phys. 66, 2962–2967 (1989)
Dewaele, A., Fiquet, G., Andrault, D. & Hausermann, D. P-V-T equation of state of periclase from synchrotron radiation measurements. J. Geophys. Res. 105, 2869–2877 (2000)
We greatly appreciate the comments by I. Jackson. Suggestions from E. Ohtani, C. Bina, S. Karato and S.-H. Shim improved the manuscript. We also thank N. Sata and Y. Asahara for their experimental assistance at SPring-8. This study was performed under the approval of SPring-8 (proposals no. 2008B0099 and 2009A0087).
The authors declare no competing financial interests.
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Murakami, M., Ohishi, Y., Hirao, N. et al. A perovskitic lower mantle inferred from high-pressure, high-temperature sound velocity data. Nature 485, 90–94 (2012). https://doi.org/10.1038/nature11004
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