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.

  • Letter
  • Published:

Sound velocity of CaSiO3 perovskite suggests the presence of basaltic crust in the Earth’s lower mantle

Abstract

Laboratory measurements of sound velocities of high-pressure minerals provide crucial information on the composition and constitution of the deep mantle via comparisons with observed seismic velocities. Calcium silicate (CaSiO3) perovskite (CaPv) is a high-pressure phase that occurs at depths greater than about 560 kilometres in the mantle1 and in the subducting oceanic crust2. However, measurements of the sound velocity of CaPv under the pressure and temperature conditions that are present at such depths have not previously been performed, because this phase is unquenchable (that is, it cannot be physically recovered to room conditions) at atmospheric pressure and adequate samples for such measurements are unavailable. Here we report in situ X-ray diffraction and ultrasonic-interferometry sound-velocity measurements at pressures of up to 23 gigapascals and temperatures of up to 1,700 kelvin (similar to the conditions at the bottom of the mantle transition region) using sintered polycrystalline samples of cubic CaPv converted from bulk glass and a multianvil apparatus. We find that cubic CaPv has a shear modulus of 126 ± 1 gigapascals (uncertainty of one standard deviation), which is about 26 per cent lower than theoretical predictions3,4 (about 171 gigapascals). This value leads to substantially lower sound velocities of basaltic compositions than those predicted for the pressure and temperature conditions at depths between 660 and 770 kilometres. This suggests accumulation of basaltic crust in the uppermost lower mantle, which is consistent with the observation of low-seismic-velocity signatures below 660 kilometres5,6 and the discovery of CaPv in natural diamond of super-deep origin7. These results could contribute to our understanding of the existence and behaviour of subducted crust materials in the deep mantle.

This is a preview of subscription content, access via your institution

Access options

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

Fig. 1: Radiography images and X-ray measurements of the sample during synthesis of CaSiO3 perovskite at high pressure and temperature.
Fig. 2: Travel time of P and S waves through the CaPv sample at high pressure and temperature.
Fig. 3: Shear and longitudinal sound velocities of tetragonal and cubic CaSiO3 perovskite.
Fig. 4: Comparison of sound velocities of pyrolite, MORB and harzburgite compositions with representative seismological models in the lower MTR.

Similar content being viewed by others

Data availability

Source data for Fig. 3 are provided in Supplementary Information.

References

  1. Irifune, T. Absence of an aluminous phase in the upper part of the Earth’s lower mantle. Nature 370, 131–133 (1994).

    Article  ADS  CAS  Google Scholar 

  2. Hirose, K. & Fei, Y. Subsolidus and melting phase relations of basaltic composition in the uppermostlower mantle. Geochim. Cosmochim. Acta 66, 2099–2108 (2002).

    Article  ADS  CAS  Google Scholar 

  3. Stixrude, L., Lithgow-Bertelloni, C., Kiefer, B. & Fumagalli, P. Phase stability and shear softening in CaSiO3 perovskite at high pressure. Phys. Rev. B 75, 024108 (2007).

    Article  ADS  Google Scholar 

  4. Tsuchiya, T. Elasticity of subducted basaltic crust at the lower mantle pressures: Insights on the nature of deep mantle heterogeneity. Phys. Earth Planet. Inter. 188, 142–149 (2011).

    Article  ADS  CAS  Google Scholar 

  5. Schmandt, B., Jacobsen, S. D., Becker, T. W. & Liu, Z. Dehydration melting at the top of the lower mantle. Science 344, 1265–1268 (2014).

    Article  ADS  CAS  PubMed  Google Scholar 

  6. Liu, Z., Park, J. & Karato, S.-i. Seismological detection of low-velocity anomalies surrounding the mantle transition zone in Japan subduction zone. Geophys. Res. Lett. 43, 2480–2487 (2016).

    Article  ADS  Google Scholar 

  7. Nestola, F. et al. CaSiO3 perovskite in diamond indicates the recycling of oceanic crust into the lower mantle. Nature 555, 237–241 (2018).

    Article  ADS  CAS  PubMed  Google Scholar 

  8. Irifune, T. et al. Sound velocities of majorite garnet and the composition of the mantle transition region. Nature 451, 814–817 (2008).

    Article  ADS  CAS  PubMed  Google Scholar 

  9. Kurnosov, A., Marquardt, H., Frost, D. J., Ballaran, T. B. & Ziberna, L. Evidence for a Fe3+-rich pyrolitic lower mantle from (Al,Fe)-bearing bridgmanite elasticity data. Nature 37, 1–16 (2017).

    Google Scholar 

  10. Irifune, T. & Ringwood, A. E. Phase transformations in a harzburgite composition to 26 GPa: implications for dynamical behaviour of the subducting slab. Earth Planet. Sci. Lett. 86, 365–376 (1987).

    Article  ADS  CAS  Google Scholar 

  11. Xu, W., Lithgow-Bertelloni, C., Stixrude, L. & Ritsema, J. The effect of bulk composition and temperature on mantle seismic structure. Earth Planet. Sci. Lett. 275, 70–79 (2008).

    Article  ADS  CAS  Google Scholar 

  12. Ballmer, M. D., Schmerr, N. C., Nakagawa, T. & Ritsema, J. Compositional mantle layering revealed by slab stagnation at ~1000-km depth. Sci. Adv. 1, e1500815 (2015).

    Article  ADS  PubMed  PubMed Central  Google Scholar 

  13. Saikia, A., Frost, D. J. & Rubie, D. C. Splitting of the 520-kilometer seismic discontinuity and chemical heterogeneity in the mantle. Science 319, 1515–1518 (2008).

    ADS  CAS  PubMed  Google Scholar 

  14. Irifune, T. & Ringwood, A. E. Phase transformation in subducted oceanic crust and buoyancy relationships at depths of 600–800 km in the mantle. Earth Planet. Sci. Lett. 117, 101–110 (1993).

    Article  ADS  CAS  Google Scholar 

  15. Kesson, S. E., Fitz Gerald, J. D. & Shelley, J. M. G. Mineral chemistry and density of subducted basaltic crust at lower mantle pressures. Nature 372, 767–769 (1994).

    Article  ADS  CAS  Google Scholar 

  16. Li, B., Kung, J. & Liebermann, R. C. Modern techniques in measuring elasticity of Earth materials at high pressure and high temperature using ultrasonic interferometry in conjunction with synchrotron X-radiation in multi-anvil apparatus. Phys. Earth Planet. Inter. 143–144, 559–574 (2004).

    Article  ADS  Google Scholar 

  17. Kudo, Y. et al. Sound velocity measurements of CaSiO3 perovskite to 133 GPa and implications for lowermost mantle seismic anomalies. Earth Planet. Sci. Lett. 349–350, 1–7 (2012).

    Article  ADS  Google Scholar 

  18. Shim, S.-H. Tetragonal structure of CaSiO3 perovskite above 20 GPa. Geophys. Res. Lett. 29, 2166 (2002).

    Article  ADS  Google Scholar 

  19. Komabayashi, T., Hirose, K., Sata, N., Ohishi, Y. & Dubrovinsky, L. S. Phase transition in CaSiO3 perovskite. Earth Planet. Sci. Lett. 260, 564–569 (2007).

    Article  ADS  CAS  Google Scholar 

  20. Carpenter, M. A., Li, B. & Liebermann, R. C. Elastic anomalies accompanying phase transitions in (Ca,Sr)TiO3 perovskites: part III. Experimental investigation of polycrystalline samples. Am. Mineral. 92, 344–355 (2007).

    Article  ADS  CAS  Google Scholar 

  21. Sun, T., Zhang, D.-B. & Wentzcovitch, R. M. Dynamic stabilization of cubic CaSiO3 perovskite at high temperatures and pressures from ab initio molecular dynamics. Phys. Rev. B 89, 094109 (2014).

    Article  ADS  Google Scholar 

  22. Davies, G. F. & Dziewonski, A. M. Homogeneity and constitution of the earth’s lower mantle and outer core. Phys. Earth Planet. Inter. 10, 336–343 (1975).

    Article  ADS  CAS  Google Scholar 

  23. Sinelnikov, Y. D., Chen, G. & Liebermann, R. C. Elasticity of CaTiO3-CaSiO3 perovskites. Phys. Chem. Miner. 25, 515–521 (1998).

    Article  ADS  CAS  Google Scholar 

  24. Kawai, K. & Tsuchiya, T. Small shear modulus of cubic CaSiO3 perovskite. Geophys. Res. Lett. 42, 2718–2726 (2015).

    Article  ADS  CAS  Google Scholar 

  25. Tauzin, B., Kim, S. & Kennett, B. L. N. Pervasive seismic low-velocity zones within stagnant plates in the mantle transition zone: thermal or compositional origin? Earth Planet. Sci. Lett. 477, 1–13 (2017).

    Article  ADS  CAS  Google Scholar 

  26. Kono, Y., Irifune, T., Ohfuji, H., Higo, Y. & Funakoshi, K.-I. Sound velocities of MORB and absence of a basaltic layer in the mantle transition region. Geophys. Res. Lett. 39, L24306 (2012).

    Article  ADS  Google Scholar 

  27. Murakami, M., Hirose, K., Yurimoto, H., Nakashima, S. & Takafuji, N. Water in Earth’s lower mantle. Science 295, 1885–1887 (2002).

    Article  ADS  CAS  PubMed  Google Scholar 

  28. Litasov, K. et al. Water solubility in Mg-perovskites and water storage capacity in the lower mantle. Earth Planet. Sci. Lett. 211, 189–203 (2003).

    Article  ADS  CAS  Google Scholar 

  29. Brodholt, J. P. Pressure-induced changes in the compression mechanism of aluminous perovskite in the Earth’s mantle. Nature 407, 620–622 (2000).

    Article  ADS  CAS  PubMed  Google Scholar 

  30. Bolfan-Casanova, N., Keppler, H. & Rubie, D. C. Water partitioning at 660 km depth and evidence for very low water solubility in magnesium silicate perovskite. Geophys. Res. Lett. 30, 1905 (2003).

    Article  ADS  Google Scholar 

  31. Walter, M. J. et al. Deep mantle cycling of oceanic crust: evidence from diamonds and their mineral inclusions. Science 334, 54–57 (2011).

    Article  ADS  CAS  PubMed  Google Scholar 

  32. Kaneshima, S. Seismic scatterers at the shallowest lower mantle beneath subducted slabs. Earth Planet. Sci. Lett. 286, 304–315 (2009).

    Article  ADS  CAS  Google Scholar 

  33. Wang, Y., Weidner, D. J. & Guyot, F. Thermal equation of state of CaSiO3 perovskite. J. Geophys. Res. B Solid Earth 101, 661–672 (1996).

    Article  ADS  CAS  Google Scholar 

  34. Matsui, M., Higo, Y., Okamoto, Y., Irifune, T. & Funakoshi, K. I. Simultaneous sound velocity and density measurements of NaCl at high temperatures and pressures: application as a primary pressure standard. Am. Mineral. 97, 1670–1675 (2012).

    Article  ADS  CAS  Google Scholar 

  35. Li, B. & Liebermann, R. C. Study of the Earth’s interior using measurements of sound velocities in minerals by ultrasonic interferometry. Phys. Earth Planet. Inter. 233, 135–153 (2014).

    Article  ADS  Google Scholar 

  36. Kono, Y. et al. Simultaneous structure and elastic wave velocity measurement of SiO2 glass at high pressures and high temperatures in a Paris–Edinburgh cell. Rev. Sci. Instrum. 83, 033905–033909 (2012).

    Article  ADS  PubMed  Google Scholar 

  37. Irifune, T., Shinmei, T., McCammon, C. A. & Miyajima, N. Iron partitioning and density changes of pyrolite in Earth’s lower mantle. Science 327, 193–195 (2010).

    Article  ADS  CAS  PubMed  Google Scholar 

  38. Ricolleau, A. et al. Phase relations and equation of state of a natural MORB: implications for the density profile of subducted oceanic crust in the Earth’s lower mantle. J. Geophys. Res. 115, B08202 (2010).

    Article  ADS  Google Scholar 

  39. Sueda, Y. et al. The phase boundary between CaSiO3 perovskite and Ca2SiO4+CaSi2O5 determined by in situ X-ray observations. Geophys. Res. Lett. 33, L10307 (2006).

    Article  ADS  Google Scholar 

  40. Higo, Y., Inoue, T., Irifune, T., Funakoshi, K.-I. & Li, B. Elastic wave velocities of (Mg0.91Fe0.09)2SiO4 ringwoodite under P–T conditions of the mantle transition region. Phys. Earth Planet. Inter. 166, 167–174 (2008).

    Article  ADS  CAS  Google Scholar 

  41. Sinogeikin, S. V. & Bass, J. D. Elasticity of majorite and a majorite-pyrope solid solution to high pressure: implications for the transition zone. Geophys. Res. Lett. 29, 1017 (2002).

    Article  ADS  Google Scholar 

  42. Kono, Y., Higo, Y., Ohfuji, H., Inoue, T. & Irifune, T. Elastic wave velocities of garnetite with a MORB composition up to 14 GPa. Geophys. Res. Lett. 34, L14308 (2007).

    Article  ADS  Google Scholar 

  43. Nishihara, Y., Aoki, I., Takahashi, E., Matsukage, K. N. & Funakoshi, K.-I. Thermal equation of state of majorite with MORB composition. Phys. Earth Planet. Inter. 148, 73–84 (2005).

    Article  ADS  CAS  Google Scholar 

  44. Morishima, H. et al. The high-pressure and temperature equation of state of a majorite solid solution in the system of Mg4Si4O12-Mg3Al2Si3O12. Phys. Chem. Miner. 27, 3–10 (1999).

    Article  ADS  CAS  Google Scholar 

  45. Chantel, J., Frost, D. J., McCammon, C. A., Jing, Z. & Wang, Y. Acoustic velocities of pure and iron-bearing magnesium silicate perovskite measured to 25 GPa and 1200 K. Geophys. Res. Lett. 39, L19307 (2012).

    Article  ADS  Google Scholar 

  46. 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, 18501 (2004).

    Article  ADS  CAS  Google Scholar 

  47. 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).

    Article  ADS  CAS  Google Scholar 

  48. Kono, Y. et al. P–V–T relation of MgO derived by simultaneous elastic wave velocity and in situ X-ray measurements: a new pressure scale for the mantle transition region. Phys. Earth Planet. Inter. 183, 196–211 (2010).

    Article  ADS  CAS  Google Scholar 

  49. Gréaux, S. et al. Sound velocities of aluminum-bearing stishovite in the mantle transition zone. Geophys. Res. Lett. 43, 4239–4246 (2016).

    Article  ADS  Google Scholar 

  50. Shinmei, T. et al. High-temperature and high-pressure equation of state for the hexagonal phase in the system NaAlSiO4 – MgAl2O4. Phys. Chem. Miner. 32, 594–602 (2005).

    Article  ADS  CAS  Google Scholar 

  51. Wu, Y. et al. Elasticity of single-crystal NAL phase at high pressure: A potential source of the seismic anisotropy in the lower mantle. J. Geophys. Res. B 121, 1–12 (2016).

    Google Scholar 

Download references

Acknowledgements

We thank T. Kunimoto for technical assistance in the experiments at beamline BL04B1 in SPring-8. We acknowledge Y. Kono for providing data analysis software; H. Dekura, Y. Nishihara and Y. Kudo for discussions; and G. Helffrich for comments on the manuscript. This work was supported by the JSPS Kakenhi programmes (to T.I.; number 25220712 and 15H05829).

Reviewer information

Nature thanks J. Buchen, L. Stixrude and the other anonymous reviewer(s) for their contribution to the peer review of this work.

Author information

Authors and Affiliations

Authors

Contributions

S.G. and T.I. designed the research project. A.Y. and S.G. prepared the glass starting material. Y.H., Y.T. and S.G. prepared the ultrasonic experiments in SPring-8. S.G., T.A. and Z.L. carried out the ultrasonic experiments at SPring-8 and S.G. and Y.T. analysed the data. T.I. and S.G. wrote the manuscript. All authors discussed the results and commented on the manuscript.

Corresponding author

Correspondence to Steeve Gréaux.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Extended data figures and tables

Extended Data Fig. 1 Pressure and temperature conditions of sound-velocity and density measurements conducted in the stability field of CaPv.

The pressure is calibrated against the NaCl scale34. The red line indicates the decomposition boundary of CaPv to Ca2SiO4 larnite and CaSi2O5 titanite39. Dashed lines represent the pressure–temperature paths followed during the travel-time measurements in the two cooling cycles at 15 GPa (blue) and 17 GPa (red) shown in Fig. 2b.

Extended Data Fig. 2 Schematic diagram of the high-pressure cell used in the present ultrasonic experiments.

Buffer rod, Al2O3; sample, CaSiO3 glass (Fig. 1a); pressure marker, NaCl and BN; soft medium, MgO; pressure medium, (Mg,Co)O; insulator, LaCrO3. denotes the thermocouple hot junction.

Extended Data Fig. 3 Cross-section of the experimental cell recovered after the ultrasonic experiment.

The elemental energy-dispersive spectroscopy mappings of Ca, Si, Al, Mg, Na, Cl and Au, superimposed on the backscattered-electron image of the cross-section, showed no chemical zoning in the CaSiO3 sample or at the interface with the sample and the other cell components.

Extended Data Fig. 4 Experimental longitudinal and shear moduli.

a–f, Results are shown for tetragonal CaPv at 300 K (a, b) and cubic CaPv at 900 K (c, d) and 1,500 K (e, f) as a function of unit-cell volume of CaPv. The solid lines represent fits of the experimental data with the finite-strain EOS (equations (1)–(12)) and the shaded areas represent the 95% confidence intervals, calculated from the trade-off between KS0 and K′ (Extended Data Fig. 4a–e) and G0 and G′ (Extended Data Fig. 4b–f). Most of our experimental data agree within the 95% confidence intervals, demonstrating the small correlation coefficients between the fitted variables.

Extended Data Table 1 Thermoelastic properties of tetragonal and cubic CaSiO3 perovskites
Extended Data Table 2 Correlation matrix of elastic parameters of tetragonal CaPv
Extended Data Table 3 Correlation matrix of thermoelastic parameters of cubic CaPv
Extended Data Table 4 Thermoelastic parameters of major mantle minerals

Supplementary information

Supplementary Table 1

Pressure and temperature conditions of the P- and S-wave velocity and 567 density measurements.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Gréaux, S., Irifune, T., Higo, Y. et al. Sound velocity of CaSiO3 perovskite suggests the presence of basaltic crust in the Earth’s lower mantle. Nature 565, 218–221 (2019). https://doi.org/10.1038/s41586-018-0816-5

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41586-018-0816-5

This article is cited by

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