A widely accepted explanation for deep-focus earthquakes is that they are caused by the delayed transformation kinetics of dry olivine, which would seem to require dry subducting slabs. However, many geochemical and geophysical observations and mineral physics data indicate that water is present within both hydrous and nominally anhydrous minerals, implying hydrated subducting slabs. The presence of metastable olivine in wet slabs is therefore paradoxical, and the hydration state of the slabs remains an open question. Here, we report results of water-partitioning experiments between olivine, wadsleyite and a major dense hydrous magnesium silicate in slabs, hydrous phase A, under water-undersaturated conditions. We show that olivine and wadsleyite coexisting with hydrous phase A are kinetically dry and contain less than 1 ppm and approximately 300 ppm water, respectively. Our results suggest that olivine and wadsleyite show dry transformation kinetics even in wet slabs. It is therefore possible that olivine transformation as a cause of deep-focus earthquakes and large slab deformation creating stagnant slabs could occur in the water-undersaturated wet slabs. These processes could be caused jointly by dehydration of hydrous minerals and the subsequent rapid phase transformation when the dehydration starts at lower temperatures than the phase transformation.
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Unsupervised machine learning reveals slab hydration variations from deep earthquake distributions beneath the northwest Pacific
Communications Earth & Environment Open Access 10 March 2022
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All data used in this paper are available on Zenodo (https://doi.org/10.5281/zenodo.3936232). Any other data can be requested by emailing the corresponding author.
Mei, S. & Kohlstedt, D. L. Influence of water on plastic deformation of olivine aggregates: 2. Dislocation creep regime. J. Geophys. Res. Solid Earth 105, 21471–21481 (2000).
Karato, S. I. & Jung, H. Effects of pressure on high-temperature dislocation creep in olivine. Philos. Mag. A 83, 401–414 (2003).
Kubo, T., Ohtani, E., Kato, T., Shinmei, T. & Fujino, K. Effects of water on the α–β transformation kinetics in San Carlos olivine. Science 281, 85–87 (1998).
Sung, C. M. & Burns, R. G. Kinetics of the olivine→spinel transition: implications to deep-focus earthquake genesis. Earth Planet. Sci. Lett. 32, 165–170 (1976).
Perrillat, J. P. et al. Kinetics of the olivine–ringwoodite transformation and seismic attenuation in the Earth’s mantle transition zone. Earth Planet. Sci. Lett. 433, 360–369 (2016).
Iidaka, T. & Suetsugu, D. Seismological evidence for metastable olivine inside a subducting slab. Nature 356, 593–595 (1992).
Jiang, G., Zhao, D. & Zhang, G. Seismic evidence for a metastable olivine wedge in the subducting Pacific slab under Japan Sea. Earth Planet. Sci. Lett. 270, 300–307 (2008).
Kirby, S. Mantle phase changes and deep-earthquake faulting in subducting lithosphere. Science 252, 216–224 (1991).
Green, H. W. II & Houston, H. The mechanisms of deep earthquakes. Annu. Rev. Earth Planet. Sci. 23, 169–213 (1995).
Schubnel, A. et al. Deep-focus earthquake analogs recorded at high pressure and temperature in the laboratory. Science 341, 1377–1380 (2013).
Kawakatsu, H. & Yoshioka, S. Metastable olivine wedge and deep dry cold slab beneath southwest Japan. Earth Planet. Sci. Lett. 303, 1–10 (2011).
Green, H. W. II, Chen, W. P. & Brudzinski, M. R. Seismic evidence of negligible water carried below 400-km depth in subducting lithosphere. Nature 467, 828–831 (2010).
Hosoya, T., Kubo, T., Ohtani, E., Sano, A. & Funakoshi, K. I. Water controls the fields of metastable olivine in cold subducting slabs. Geophys. Res. Lett. 32, L17305 (2005).
Du Frane, W. L., Sharp, T. G., Mosenfelder, J. L. & Leinenweber, K. Ringwoodite growth rates from olivine with ~75 ppmw H2O: metastable olivine must be nearly anhydrous to exist in the mantle transition zone. Phys. Earth Planet. Inter. 219, 1–10 (2013).
Peslier, A. H., Schönbächler, M., Busemann, H. & Karato, S. I. Water in the Earth’s interior: distribution and origin. Space Sci. Rev. 212, 743–810 (2017).
Hacker, B. R., Peacock, S. M., Abers, G. A. & Holloway, S. D. Subduction factory 2. Are intermediate‐depth earthquakes in subducting slabs linked to metamorphic dehydration reactions? J. Geophys. Res. Solid Earth 108, 2030 (2003).
Schmidt, M. W. & Poli, S. Experimentally based water budgets for dehydrating slabs and consequences for arc magma generation. Earth Planet. Sci. Lett. 163, 361–379 (1998).
Yamasaki, T. & Seno, T. Double seismic zone and dehydration embrittlement of the subducting slab. J. Geophys. Res. 108, 2212 (2003).
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. 116, 1401 (2011).
Peacock, S. M. Are the lower planes of double seismic zones caused by serpentine dehydration in subducting oceanic mantle? Geology 29, 299–302 (2001).
Seno, T. & Yamanaka, Y. in Subduction: Top to Bottom (eds Bebout, G. E. et al.) 347–355 (AGU, 1996).
Hirano, N. et al. Volcanism in response to plate flexure. Science 313, 1426–1428 (2006).
Cai, C., Wiens, D. A., Shen, W. & Eimer, M. Water input into the Mariana subduction zone estimated from ocean-bottom seismic data. Nature 563, 389–392 (2018).
Ranero, C. R., Morgan, J. P., McIntosh, K. & Reichert, C. Bending-related faulting and mantle serpentinization at the Middle America trench. Nature 425, 367–373 (2003).
Komabayashi, T., Omori, S. & Maruyama, S. Petrogenetic grid in the system MgO–SiO2–H2O up to 30 GPa, 1600 °C: applications to hydrous peridotite subducting into the Earth’s deep interior. J. Geophys. Res. 109, B03206 (2004).
Kirby, S. H., Okal, E. A., Stein, S. & Rubie, D. C. Metastable mantle phase transformations and deep earthquake in subducting oceanic lithosphere. Rev. Geophys. 34, 261–306 (1996).
Bolfan-Casanova, N. Water in the Earth’s mantle. Mineral. Mag. 69, 229–257 (2005).
Smyth, J. R., Frost, D. J., Nestola, F., Holl, C. M. & Bromiley, G. Olivine hydration in the deep upper mantle: effects of temperature and silica activity. Geophys. Res. Lett. 33, L15301 (2006).
Litasov, K. D., Shatskiy, A., Ohtani, E. & Katsura, T. Systematic study of hydrogen incorporation into Fe-free wadsleyite. Phys. Chem. Miner. 38, 75–84 (2011).
Hae, R., Ohtani, E., Kubo, T., Koyama, T. & Utada, H. Hydrogen diffusivity in wadsleyite and water distribution in the mantle transition zone. Earth Planet. Sci. Lett. 243, 141–148 (2006).
Demouchy, S. & Mackwell, S. Water diffusion in synthetic iron-free forsterite. Phys. Chem. Miner. 30, 486–494 (2003).
Demouchy, S. & Mackwell, S. Mechanisms of hydrogen incorporation and diffusion in iron-bearing olivine. Phys. Chem. Miner. 33, 347–355 (2006).
Kudo, T., Ohtani, E., Hae, R. & Shimojuku, A. Diffusion of hydrogen in ringwoodite. AIP Conf. Proc. 833, 148–149 (2006).
Keppler, H. & Bolfan-Casanova, N. Thermodynamics of water solubility and partitioning. Rev. Mineral. Geochem. 62, 193–230 (2006).
Kubo, T., Ohtani, E. & Funakoshi, K. I. Nucleation and growth kinetics of the α–β transformation in Mg2SiO4 determined by in situ synchrotron powder X-ray diffraction. Am. Mineral. 89, 285–293 (2004).
Ferrand, T. P. et al. Dehydration-driven stress transfer triggers intermediate-depth earthquakes. Nat. Commun. 8, 15247 (2017).
Quinteros, J. & Sobolev, S. V. Constraining kinetics of metastable olivine in the Marianas slab from seismic observations and dynamic models. Tectonophysics 526, 48–55 (2012).
Yoshioka, S., Torii, Y. & Riedel, M. R. Impact of phase change kinetics on the Mariana slab within the framework of 2-D mantle convection. Phys. Earth Planet. Inter. 240, 70–81 (2015).
Zahradnik, J. et al. A recent deep earthquake doublet in light of long-term evolution of Nazca subduction. Sci. Rep. 7, 45153 (2017).
Karato, S. I., Riedel, M. R. & Yuen, D. A. Rheological structure and deformation of subducted slabs in the mantle transition zone: implications for mantle circulation and deep earthquakes. Phys. Earth Planet. Inter. 127, 83–108 (2001).
Mohiuddin, A., Karato, S. I. & Girard, J. Slab weakening during the olivine to ringwoodite transition in the mantle. Nat. Geosci. 13, 170–174 (2020).
Čı́žková, H., van Hunen, J., van den Berg, A. P. & Vlaar, N. J. The influence of rheological weakening and yield stress on the interaction of slabs with the 670 km discontinuity. Earth Planet. Sci. Lett. 199, 447–457 (2002).
Rosa, A. D. et al. Evolution of grain sizes and orientations during phase transitions in hydrous Mg2SiO4. J. Geophys. Res. 121, 7161–7176 (2016).
Fukao, Y., Obayashi, M. & Nakakuki, T. & Deep Slab Project Group. Stagnant slab: a review. Annu. Rev. Earth Planet. Sci. 37, 19–46 (2009).
Tielke, J. A., Zimmerman, M. E. & Kohlstedt, D. L. Hydrolytic weakening in olivine single crystals. J. Geophys. Res. 122, 3465–3479 (2017).
Richard, G., Monnereau, M. & Rabinowicz, M. Slab dehydration and fluid migration at the base of the upper mantle: implications for deep earthquake mechanisms. Geophys. J. Int. 168, 1291–1304 (2017).
Kagi, H., Parise, J. B., Cho, H., Rossman, G. R. & Loveday, J. S. Hydrogen bonding interactions in phase A [Mg7Si2O8(OH)6] at ambient and high pressure. Phys. Chem. Miner. 27, 225–233 (2000).
Purevjav, N., Okuchi, T., Tomioka, N., Wang, X. & Hoffmann, C. Quantitative analysis of hydrogen sites and occupancy in deep mantle hydrous wadsleyite using single crystal neutron diffraction. Sci. Rep. 6, 34988 (2016).
Purevjav, N., Okuchi, T. & Hoffmann, C. Strong hydrogen bonding in a dense hydrous magnesium silicate discovered by neutron Laue diffraction. IUCrJ 7, 370–374 (2020).
Pacalo, R. E. & Parise, J. B. Crystal structure of superhydrous B, a hydrous magnesium silicate synthesized at 1400 °C and 20 GPa. Am. Mineral. 77, 681–684 (1992).
Beran, A. & Putnis, A. A model of the OH positions in olivine, derived from infrared-spectroscopic investigations. Phys. Chem. Miner. 9, 57–60 (1983).
Brodholt, J. P. & Refson, K. An ab initio study of hydrogen in forsterite and a possible mechanism for hydrolytic weakening. J. Geophys. Res. Solid Earth 105, 18977–18982 (2000).
Ingrin, J. & Blanchard, M. Diffusion of hydrogen in minerals. Rev. Mineral. Geochem. 62, 291–320 (2006).
Withers, A. C., Bureau, H., Raepsaet, C. & Hirschmann, M. M. Calibration of infrared spectroscopy by elastic recoil detection analysis of H in synthetic olivine. Chem. Geol. 334, 92–98 (2012).
Bolfan-Casanova, N. et al. Examination of water quantification and incorporation in transition zone minerals: wadsleyite, ringwoodite and phase D using ERDA (elastic recoil detection analysis). Front. Earth Sci. 6, 75 (2018).
We thank H. Fischer for preparation of cell assemblies, R. Njul for preparation of thin-section samples, D. Wiesner and F. Ferreira for measurements of EBSD patterns of the samples and H. Keppler for measurements of water in the samples by using FTIR, at the Bayerisches Geoinstitut. We also appreciate D. J. Frost and T. Katsura for valuable discussion on this topic and T. Withers for useful comments on the manuscript. This research was supported by the Grants-in-Aid of the German Research Foundation (no. IS350/1-1) to T.I. and the Kakenhi Grants JP15H05748 and JP20H00187 from Japan Society for the Promotion of Science to E.O. E.O. was supported also by the research award from the Alexander von Humboldt foundation.
The authors declare no competing interests.
Peer review information Nature Geoscience thanks Jean-Philippe Perrillat and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Primary Handling Editor: Rebecca Neely.
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Water-partitioning experiments between a, forsterite and hydrous phase A and b, wadsleyite and hydrous phase A. In the experiments for forsterite, oriented crystals with 200 μm a axis × 400 μm b axis × 400 μm c axis were put in the capsules as shown in the right capsule in Extended Data Fig. 1a.
Extended Data Fig. 2 Representative X-ray diffraction patterns of the recovered samples at the surrounding part of the single crystals.
a, 10 GPa and 800 °C (S7423). b, 12 GPa and 900 °C (H5073). Fo, forsterite; Wd, wadsleyite; Cen, clinoenstatite; PhA, hydrous phase A.
Experimental conditions and results of phase identification and water contents in single crystals.
Details of FTIR measurements of forsterite and wadsleyite single crystals.
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Ishii, T., Ohtani, E. Dry metastable olivine and slab deformation in a wet subducting slab. Nat. Geosci. 14, 526–530 (2021). https://doi.org/10.1038/s41561-021-00756-7
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