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Retention of water in subducted slabs under core–mantle boundary conditions

Nature Geoscience volume 17, pages 697–704 (2024)Cite this article

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Abstract

The hydrated SiO2 phase is a main carrier of water in subducting slabs in the lower mantle. Assuming its dehydration at high temperatures above the core–mantle boundary, it has been speculated that seismic anomalies observed in this enigmatic region and the uppermost core might be attributable to water released from slabs. Here we report melting experiments on a hydrous basalt up to conditions of the core–mantle boundary region at 25–144 GPa and 2,900–4,100 K. Secondary-ion mass spectrometry measurements with high-resolution imaging techniques reveal that the SiO2 phase and SiO2–AlOOH solid solution contain 0.5–3.6 wt% and ~3.5 wt% H2O, respectively, coexisting with melts holding 0.9–2.6 wt% H2O. The high solubility into SiO2 and high SiO2/melt partition coefficient of water at the high temperatures of the core–mantle boundary region suggest that practically water does not escape from subducted slabs at the base of the mantle. Even if the core–mantle boundary temperature were high enough to melt subducted crustal materials, most of the H2O would remain in the solid residue rather than entering a partial melt. Previously proposed consequences of slab dehydration are therefore unlikely to be responsible for chemical heterogeneities in the lowermost mantle and the topmost core.

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Fig. 1: Experimental pressure–temperature conditions and lower-mantle geotherms.
Fig. 2: Cross sections of partially molten samples.
Fig. 3: Variations in hydrated SiO2.

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Data availability

All data supporting this study are available via Zenodo at https://zenodo.org/records/10901809 (ref. 72).

References

  1. Ohtani, E. The role of water in Earth’s mantle. Natl Sci. Rev. 7, 224–232 (2020).

    Article  CAS  Google Scholar 

  2. Walter, M. J. Water transport to the core–mantle boundary. Natl Sci. Rev. 8, nwab007 (2021).

    Article  Google Scholar 

  3. Okamoto, K. & Maruyama, S. The high-pressure synthesis of lawsonite in the MORB + H2O system. Am. Mineral. 84, 362–373 (1999).

    Article  CAS  Google Scholar 

  4. van Keken, P. E., Hacker, B. R., Syracuse, E. M. & Abers, G. A. Subduction factory: 4. Depth-dependent flux of H2O from subducting slabs worldwide. J. Geophys. Res. B 116, B01401 (2011).

    Google Scholar 

  5. Hatakeyama, K., Katayama, I., Hirauchi, K. & Michibayashi, K. Mantle hydration along outer-rise faults inferred from serpentinite permeability. Sci. Rep. 7, 13870 (2017).

    Article  Google Scholar 

  6. Tsuchiya, J. First principles prediction of a new high-pressure phase of dense hydrous magnesium silicates in the lower mantle. Geophys. Res. Lett. 40, 4570–4573 (2013).

    Article  CAS  Google Scholar 

  7. Panero, W. R. & Caracas, R. Stability of phase H in the MgSiO4H2–AlOOH–SiO2 system. Earth Planet. Sci. Lett. 463, 171–177 (2017).

    Article  CAS  Google Scholar 

  8. Nishi, M. et al. Stability of hydrous silicate at high pressures and water transport to the deep lower mantle. Nat. Geosci. 7, 224–227 (2014).

    Article  CAS  Google Scholar 

  9. Ohtani, E., Amaike, Y., Kamada, S., Sakamaki, T. & Hirao, N. Stability of hydrous phase H MgSiO4H2 under lower mantle conditions. Geophys. Res. Lett. 41, 8283–8287 (2014).

    Article  CAS  Google Scholar 

  10. Liu, Z. et al. Bridgmanite is nearly dry at the top of the lower mantle. Earth Planet. Sci. Lett. 570, 117088 (2021).

    Article  CAS  Google Scholar 

  11. Bolfan-Casanova, N., Mackwell, S., Keppler, H., McCammon, C. & Rubie, D. C. Pressure dependence of H solubility in magnesiowüstite up to 25 GPa: implications for the storage of water in the Earth’s lower mantle. Geophys. Res. Lett. 29, 89-1–89-4 (2002).

    Article  Google Scholar 

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

    Article  CAS  Google Scholar 

  13. Fu, S. et al. Water concentration in single-crystal (Al,Fe)-bearing bridgmanite grown from the hydrous melt: implications for dehydration melting at the topmost lower mantle. Geophys. Res. Lett. 46, 10346–10357 (2019).

    Article  CAS  Google Scholar 

  14. Panero, W. R., Benedetti, L. R. & Jeanloz, R. Transport of water into the lower mantle: role of stishovite. J. Geophys. Res. B 108, 2039 (2003).

    Article  Google Scholar 

  15. Lin, Y., Hu, Q., Meng, Y., Walter, M. & Mao, H. K. Evidence for the stability of ultrahydrous stishovite in Earth’s lower mantle. Proc. Natl Acad. Sci. USA 117, 184–189 (2020).

    Article  CAS  Google Scholar 

  16. Nisr, C. et al. Large H2O solubility in dense silica and its implications for the interiors of water-rich planets. Proc. Natl Acad. Sci. USA 117, 9747–9754 (2020).

    Article  CAS  Google Scholar 

  17. Lin, Y. et al. Hydrous SiO2 in subducted oceanic crust and H2O transport to the core–mantle boundary. Earth Planet. Sci. Lett. 594, 117708 (2022).

    Article  CAS  Google Scholar 

  18. Ishii, T. et al. Superhydrous aluminous silica phases as major water hosts in high-temperature lower mantle. Proc. Natl Acad. Sci. USA 119, e2211243119 (2022).

    Article  CAS  Google Scholar 

  19. Hirose, K., Takafuji, N., Sata, N. & Ohishi, Y. Phase transition and density of subducted MORB crust in the lower mantle. Earth Planet. Sci. Lett. 237, 239–251 (2005).

    Article  CAS  Google Scholar 

  20. 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. B 115, 8202 (2010).

    Article  Google Scholar 

  21. Irifune, T., Ringwood, A. E. & Hibberson, W. O. Subduction of continental crust and terrigenous and pelagic sediments: an experimental study. Earth Planet. Sci. Lett. 126, 351–368 (1994).

    Article  CAS  Google Scholar 

  22. Komabayashi, T., Maruyama, S. & Rino, S. A speculation on the structure of the D″ layer: the growth of anti-crust at the core–mantle boundary through the subduction history of the Earth. Gondwana Res. 15, 342–353 (2009).

    Article  CAS  Google Scholar 

  23. Ohira, I. et al. Stability of a hydrous δ-phase, AlOOH–MgSiO2(OH)2, and a mechanism for water transport into the base of lower mantle. Earth Planet. Sci. Lett. 401, 12–17 (2014).

    Article  CAS  Google Scholar 

  24. Nishi, M. et al. Solid solution and compression behavior of hydroxides in the lower mantle. J. Geophys. Res. B 124, 10231–10239 (2019).

    Article  CAS  Google Scholar 

  25. Walter, M. J. et al. The stability of hydrous silicates in Earth’s lower mantle: experimental constraints from the systems MgO–SiO2–H2O and MgO–Al2O3–SiO2–H2O. Chem. Geol. 418, 16–29 (2015).

    Article  CAS  Google Scholar 

  26. Nomura, R. et al. Low core–mantle boundary temperature inferred from the solidus of pyrolite. Science 343, 522–525 (2014).

    Article  CAS  Google Scholar 

  27. Kim, T. et al. Low melting temperature of anhydrous mantle materials at the core–mantle boundary. Geophys. Res. Lett. 47, e2020GL089345 (2020).

    Article  CAS  Google Scholar 

  28. Fiquet, G. et al. Melting of peridotite to 140 gigapascals. Science 329, 1516–1518 (2010).

    Article  CAS  Google Scholar 

  29. Andrault, D. et al. Solidus and liquidus profiles of chondritic mantle: implication for melting of the Earth across its history. Earth Planet. Sci. Lett. 304, 251–259 (2011).

    Article  CAS  Google Scholar 

  30. Deschamps, F. & Cobden, L. Estimating core–mantle boundary temperature from seismic shear velocity and attenuation. Front. Earth Sci. 10, 1031507 (2022).

    Article  Google Scholar 

  31. Mashino, I., Murakami, M. & Ohtani, E. Sound velocities of δ-AlOOH up to core–mantle boundary pressures with implications for the seismic anomalies in the deep mantle. J. Geophys. Res. B 121, 595–609 (2016).

    Article  CAS  Google Scholar 

  32. Hu, Q. et al. FeO2 and FeOOH under deep lower-mantle conditions and Earth’s oxygen–hydrogen cycles. Nature 534, 241–244 (2016).

    Article  CAS  Google Scholar 

  33. Liu, J. et al. Hydrogen-bearing iron peroxide and the origin of ultralow-velocity zones. Nature 551, 494–497 (2017).

    Article  CAS  Google Scholar 

  34. Mao, H.-K. et al. When water meets iron at Earth’s core–mantle boundary. Natl Sci. Rev. 4, 870–878 (2017).

    Article  CAS  Google Scholar 

  35. Yu, S. & Garnero, E. J. Ultralow velocity zone locations: a global assessment. Geochem. Geophys. Geosyst. 19, 396–414 (2018).

    Article  Google Scholar 

  36. Helffrich, G. & Kaneshima, S. Outer-core compositional stratification from observed core wave speed profiles. Nature 468, 807–810 (2010).

    Article  CAS  Google Scholar 

  37. Kim, T. et al. A hydrogen-enriched layer in the topmost outer core sourced from deeply subducted water. Nat. Geosci. 16, 1208–1214 (2023).

    Article  CAS  Google Scholar 

  38. Ito, E., Kubo, A., Katsura, T. & Walter, M. J. Melting experiments of mantle materials under lower mantle conditions with implications for magma ocean differentiation. Phys. Earth Planet. Inter. 143, 397–406 (2004).

    Article  Google Scholar 

  39. Tateno, S., Hirose, K. & Ohishi, Y. Melting experiments on peridotite to lowermost mantle conditions. J. Geophys. Res. B 119, 4684–4694 (2014).

    Article  CAS  Google Scholar 

  40. Andrault, D. et al. Melting of subducted basalt at the core–mantle boundary. Science 344, 892–895 (2014).

    Article  CAS  Google Scholar 

  41. Tateno, S. et al. Melting phase relations and element partitioning in MORB to lowermost mantle conditions. J. Geophys. Res. B 123, 5515–5531 (2018).

    Article  Google Scholar 

  42. Lakshtanov, D. L. et al. The post-stishovite phase transition in hydrous alumina-bearing SiO2 in the lower mantle of the earth. Proc. Natl Acad. Sci. USA 104, 13588–13590 (2007).

    Article  CAS  Google Scholar 

  43. Umemoto, K., Kawamura, K., Hirose, K. & Wentzcovitch, R. M. Post-stishovite transition in hydrous aluminous SiO2. Phys. Earth Planet. Inter. 255, 18–26 (2016).

    Article  CAS  Google Scholar 

  44. Nomura, R., Hirose, K., Sata, N. & Ohishi, Y. Precise determination of post-stishovite phase transition boundary and implications for seismic heterogeneities in the mid–lower mantle. Phys. Earth Planet. Inter. 183, 104–109 (2010).

    Article  CAS  Google Scholar 

  45. Panero, W. R. & Stixrude, L. P. Hydrogen incorporation in stishovite at high pressure and symmetric hydrogen bonding in δ-AlOOH. Earth Planet. Sci. Lett. 221, 421–431 (2004).

    Article  CAS  Google Scholar 

  46. Liu, L. et al. Formation of an Al-rich niccolite-type silica in subducted oceanic crust: implications for water transport to the deep lower mantle. Geophys. Res. Lett. 49, e2021GL097178 (2022).

    Article  CAS  Google Scholar 

  47. Duan, Y. et al. Phase stability and thermal equation of state of δ-AlOOH: implication for water transportation to the deep lower mantle. Earth Planet. Sci. Lett. 494, 92–98 (2018).

    Article  Google Scholar 

  48. Hou, M. et al. Superionic iron oxide–hydroxide in Earth’s deep mantle. Nat. Geosci. 14, 174–178 (2021).

    Article  CAS  Google Scholar 

  49. Komabayashi, T. Hydrogen dances in the deep mantle. Nat. Geosci. 14, 116–117 (2021).

    Article  CAS  Google Scholar 

  50. Lin, Y. & Mao, H.-K. Dense hydrous silica carrying water to the deep Earth and promotion of oxygen fugacity heterogeneity. Matter Radiat. Extrem. 7, 068101 (2022).

    Article  CAS  Google Scholar 

  51. Li, M. in Mantle Convection and Surface Expressions (eds Marquardt, H. et al.) 303–328 (American Geophysical Union, 2021).

  52. Murakami, M., Hirose, K., Sata, N. & Ohishi, Y. Post-perovskite phase transition and mineral chemistry in the pyrolitic lowermost mantle. Geophys. Res. Lett. 32, L03304 (2005).

    Article  Google Scholar 

  53. Ohta, K., Hirose, K., Lay, T., Sata, N. & Ohishi, Y. Phase transitions in pyrolite and MORB at lowermost mantle conditions: implications for a MORB-rich pile above the core–mantle boundary. Earth Planet. Sci. Lett. 267, 107–117 (2008).

    Article  CAS  Google Scholar 

  54. Hunt, S. A. et al. Weakening of calcium iridate during its transformation from perovskite to post-perovskite. Nat. Geosci. 2, 794–797 (2009).

    Article  CAS  Google Scholar 

  55. Ammann, M. W., Brodholt, J. P., Wookey, J. & Dobson, D. P. First-principles constraints on diffusion in lower-mantle minerals and a weak D″ layer. Nature 465, 462–465 (2010).

    Article  CAS  Google Scholar 

  56. Griggs, D. Hydrolytic weakening of quartz and other silicates. Geophys. J. Int. 14, 19–31 (1967).

    Article  CAS  Google Scholar 

  57. Li, Y. et al. Effects of the compositional viscosity ratio on the long-term evolution of thermochemical reservoirs in the deep mantle. Geophys. Res. Lett. 46, 9591–9601 (2019).

    Article  CAS  Google Scholar 

  58. Wang, W. et al. Velocity and density characteristics of subducted oceanic crust and the origin of lower-mantle heterogeneities. Nat. Commun. 11, 64 (2020).

    Article  Google Scholar 

  59. Zhang, Y. et al. Elasticity of hydrated Al-bearing stishovite and post-stishovite: implications for understanding regional seismic VS anomalies along subducting slabs in the lower mantle. J. Geophys. Res. B 127, e2021JB023170 (2022).

    Article  CAS  Google Scholar 

  60. Brown, J. M. & Shankland, T. J. Thermodynamic parameters in the Earth as determined from seismic profiles. Geophys. J. Int. 66, 579–596 (1981).

    Article  Google Scholar 

  61. Tagawa, S. et al. Experimental evidence for hydrogen incorporation into Earth’s core. Nat. Commun. 12, 2588 (2021).

    Article  CAS  Google Scholar 

  62. Hirose, K., Fei, Y., Ma, Y. & Mao, H.-K. The fate of subducted basaltic crust in the Earth’s lower mantle. Nature 397, 53–56 (1999).

    Article  CAS  Google Scholar 

  63. Hasegawa, M., Hirose, K., Oka, K. & Ohishi, Y. Liquidus phase relations and solid–liquid partitioning in the Fe–Si–C system under core pressures. Geophys. Res. Lett. 48, e2021GL092681 (2021).

    Article  CAS  Google Scholar 

  64. Hirao, N. et al. New developments in high-pressure X-ray diffraction beamline for diamond anvil cell at SPring-8. Matter Radiat. Extrem. 5, 018403 (2020).

    Article  Google Scholar 

  65. 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).

    Article  CAS  Google Scholar 

  66. Hirose, K. et al. Crystallization of silicon dioxide and compositional evolution of the Earth’s core. Nature 543, 99–102 (2017).

    Article  CAS  Google Scholar 

  67. Yurimoto, H., Nagashima, K. & Kunihiro, T. High precision isotope micro-imaging of materials. Appl. Surf. Sci. 203/204, 793–797 (2003).

    Article  Google Scholar 

  68. Sakamoto, N. et al. Remnants of the early solar system water enriched in heavy oxygen isotopes. Science 317, 231–233 (2007).

    Article  CAS  Google Scholar 

  69. Greenwood, J. P. et al. Hydrogen isotope ratios in lunar rocks indicate delivery of cometary water to the Moon. Nat. Geosci. 4, 79–82 (2011).

    Article  CAS  Google Scholar 

  70. Yurimoto, H., Kurosawa, M. & Sueno, S. Hydrogen analysis in quartz crystals and quartz glasses by secondary ion mass spectrometry. Geochim. Cosmochim. Acta 53, 751–755 (1989).

    Article  CAS  Google Scholar 

  71. Yoshimura, S. Diffusive fractionation of H2O and CO2 during magma degassing. Chem. Geol. 411, 172–181 (2015).

    Article  CAS  Google Scholar 

  72. Tsutsumi, Y. et al. Retention of water in subducted slabs under core- mantle boundary conditions. Zenodo https://doi.org/10.5281/zenodo.10901809 (2024).

  73. Bolfan-Casanova, N., Andrault, D., Amiguet, E. & Guignot, N. Equation of state and post-stishovite transformation of Al-bearing silica up to 100 GPa and 3000 K. Phys. Earth Planet. Inter. 174, 70–77 (2009).

    Article  CAS  Google Scholar 

  74. Andrault, D. et al. Phase diagram and P–V–T equation of state of Al-bearing seifertite at lowermost mantle conditions. Am. Mineral. 99, 2035–2042 (2014).

    Article  Google Scholar 

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Acknowledgements

We acknowledge K. Yonemitsu for assisting in focused ion beam and EPMA analyses, and G. Helffrich for discussion. Comments by W. Panero on an earlier version of the paper were helpful. Synchrotron XRD measurements were carried out at BL10XU, SPring-8 (proposals 2020A0072, 2020A0066, 2021A0072 and 2021A1481). This work was supported by grants from JSPS Kakenhi to K.H. and H.Y. and by the ‘Imaging Platform’ programme of MEXT.

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Author notes

  1. Shoh Tagawa

    Present address: Institute for Excellence in Educational Innovation, Chiba University, Chiba, Japan

Authors and Affiliations

  1. Department of Earth and Planetary Science, The University of Tokyo, Tokyo, Japan

    Yutaro Tsutsumi, Kei Hirose & Shoh Tagawa

  2. Creative Research Institution (CRIS), Hokkaido University, Sapporo, Japan

    Naoya Sakamoto & Hisayoshi Yurimoto

  3. Earth–Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan

    Kei Hirose, Shoh Tagawa & Koichiro Umemoto

  4. Japan Synchrotron Radiation Research Institute, Sayo, Japan

    Yasuo Ohishi

  5. Department of Natural History Sciences, Hokkaido University, Sapporo, Japan

    Hisayoshi Yurimoto

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Contributions

The project was designed by K.H. and led by Y.T. SIMS analyses were performed by N.S., H.Y., S.T. and Y.T. XRD data were collected by Y.T. and Y.O. Y.T., K.H. and K.U. wrote the paper, and all authors commented on it.

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Correspondence to Yutaro Tsutsumi or Kei Hirose.

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Nature Geoscience thanks Michael Walter and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Primary Handling Editor: Alison Hunt, in collaboration with the Nature Geoscience team.

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Extended data

Extended Data Fig. 1 XRD pattern for a solid part around a melt pocket obtained after quenching temperature in run #9.

SC, hydrated CaCl2-type SiO2; MP, bridgmanite; CP, CaSiO3 perovskite; Al, SiO2-AlOOH ss. Peak separations of SC121/211 and SC011/101 indicate the orthorhombic distortion of the CaCl2-type structure. This pattern includes a couple of unknown peaks, which did not show grain growth in a two-dimensional raw XRD image unlike other peaks and thus should have not derived from a heated sample.

Extended Data Fig. 2 SCAPS images of secondary ions.

Samples were heated to (a) 3,250 K at 58 GPa (run #9) and (b) 3,450 K at 121 GPa and (run #13). Same images as those in Fig. 2 for 1H+ and 28Si+. R. I., relative intensity normalized to that from a starting material. Scale bars; 10 µm.

Extended Data Fig. 3 Unit-cell volumes of Al-bearing hydrous SiO2 phases measured at 300 K.

The volumes of CaCl2-type (closed symbols) and α-PbO2-type phases (open symbols, the half unit-cell volumes are plotted for comparison) measured in this study are larger than those of dry Al-bearing SiO2 phases, likely because of the incorporation of water. Blue curve73, CaCl2-type SiO2 with 3.0 wt% Al2O3 (Alsti-06); green curve74, α-PbO2-type SiO2 with 6.0 wt% Al2O3. Pressure uncertainties are ±10%61. The volume data are presented as mean values +/- SD.

Extended Data Table 1 Lattice constants and unit-cell volumes of the SiO2 phases
Full size table

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Tsutsumi, Y., Sakamoto, N., Hirose, K. et al. Retention of water in subducted slabs under core–mantle boundary conditions. Nat. Geosci. 17, 697–704 (2024). https://doi.org/10.1038/s41561-024-01464-8

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