• Thèmes de Recherche :

    Field of expertise:

    – Experimental mineralogy and petrology, applied to Earth’s upper mantle

    – Defects in olivine and other minerals,  ionic diffusion and viscoelastoplastic deformation.

    – Concentration, distribution and mobility of H in nominally anhydrous minerals


    Field of obsession:

    – Olivine (Demouchy, Eur. J. Miner. 2021, Demouchy and Alard, Contrib Min. Petrol, 2021) and rocks hosting olivine (Demouchy and Tommasi, Earth Planet Sci. Lett., 2021), and also, Chablis, chocolate, yuzu & gyokuro, celadon and others ceramics, photography, etc.


    Main achievements:

    – Experimental quantification of hydrogen diffusion coefficients in olivine lattice and application, for the first time, to magma ascent rates estimates (Demouchy and Mackwell, Phys. Chem. Min. 2003, 2006 ; Demouchy et al., Geology, 2006) and in olivine grain boundaries (Demouchy, Earth Planet Sci. Lett., 2010).

    – Effect of high temperature and high pressure on the hydrogen storage capacity of wadsleyite and application to the deep water cycle (Demouchy et al., 2005, Am. Min.).

    – Effect of hydrogen on transport properties in mantle minerals: hydrogen enhancement of Fe-Mg diffusion in magnesiowüstite (Demouchy et al., Contrib. Min. Petrol. 2007) ; negligible hydrogen strength weakening in olivine (Demouchy et al., Phys. Earth. Planet. Int. 2012).

    – Experimentally-based flow law of olivine applicable to the Earth’s lithosphere. (Demouchy et al., Geophys. Res. Lett. 2009, Phys. Earth. Planet. Int.  2013, Tectonophys, 2014).

    – Building the database on hydrogen storage in mantle-derived rocks (e.g., invited review article Demouchy and Bolfan-Casanova, Lithos, 2016).

    – Collaborations to decipher plastic mechanisms of olivine at nanoscale (Mussi et al., Phys. Chem. Min 2014, Phil. Mag. 2015, 2017) and in particular identification for the first time of rotational defects in natural and experimentally deformed olivine polycrystals (Cordier, Demouchy et al., Nature, 2014) as well as the deformation-induced amorphization of olivine (Samae et al., Nature, 2021).

  • Responsabilités scientifiques et administratives :

    • Porteuse du projet INSU-TELLUS-SYSTER DOMINO: Deformation and mineral defects in olivine: Impact on upper mantle ductility.
    • Partenaire ANR H-Deep-ISO (PI. N. Bolfan-Casanova)
    • Membre du comité de pilotage du réseau CNRS Hautes-Pressions :
    • Membre nommée à la commission spécialisée CNRS-INSU instrumentation innovantes et transverse (CSIIT) – Représentante Terre Solide
    • Editrice associée chez American Mineralogist
    • Elue secrétaire de l’International Association of Mineralogy (
    • Membre du comité exécutif du magazine Elements (
  • Formation  & Distinctions :


    2014 – French habilitation to direct research (H.D.R., Sc.D.), Montpellier University, France. « Olivine and its crystalline defects as fundamental parameters of Earth’s dynamics ».

    2004 – PhD (Dr. rer. Nat) Bayreuth Universitaet, Germany. «Water in the Earth’s Interior: Thermodynamics and kinetics of hydrogen incorporation in olivine and wadsleyite»

    2000 – DEA Dynamics of the lithosphere, Grenoble University, France. « Etude pétrographique et géochimique des komatiites volcanoclastiques et diamantifère de Guyane Française ».

    Before: trained as a geologist in South of France (Aix-Marseille Univ.) in a large amount of boring limestone.




    2020 – Elected fellow of the Mineralogical Society of America

     2017 – CNRS honor for excellence in science (“Prime d’excellence scientifique”)

    2016 – EMU Research Excellence Medal (

     2011 CNRS honor for excellence in science (“Prime d’excellence scientifique”)

  • Publications LMV :

    Full CV in English here:


    First authors (top 10):

    Demouchy, S., (2021) Defects in Olivine. Eur. J. Mineral. 33, 249-282,

    Demouchy, S., and Alard O. (2021) Hydrogen, minor, trace and ultra-trace elements distribution in natural olivines. Contrib. Mineral. Petrol. 176, 26,

    Demouchy, S., Shcheka, S., Denis, C.M.M., Thoraval, C., (2017). Subsolidus hydrogen partitioning between nominally anhydrous minerals in garnet-bearing peridotite. Am. Min. 102, 1822-1831.

    Demouchy, S., Thoraval C., Bolfan-Casanova N., Manthilake, G., (2016). Diffusion of hydrogen in iron-bearing olivine at 3 GPa. Phys. Earth Planet. Int. doi : 10.1016/j.pepi.2016.08.005.

    Demouchy, S., and Bolfan-Casanova, N., (2016). Distribution and transport of hydrogen in the lithospheric mantle: A review. Lithos, 240–243, 402–425, doi: 10.1016/j.lithos.2015.11.012.

    Demouchy, S., Ishikawa A., Tommasi A., Alard, O., Keshav S. (2015). Characterisation of the hydration in the oceanic mantle lithosphere: peridotite xenoliths from Ontong Java Plateau as an example. Lithos. 212-215, 189–201,doi: 10.1016/j.lithos.2014.11.005.

    Demouchy, S., Mussi, A, Barou, F., Tommasi A., Cordier P.  (2014). Viscoplasticity of polycrystalline olivine at high pressure and 900 °C: outcomes from high resolution EBSD and electron tomography. Tectonophysics, 623,123-135, doi:10.1016/j.tecto.2014.03.022.

    Demouchy, S., Tommasi, A., Boffa-Ballaran, T., Cordier, P. (2013). Low strength of Earth’s uppermost mantle inferred from tri-axial deformation experiments on dry olivine crystals. Phys. Earth Planet. Int. 220: 37-49 (doi: 10.1016/j.pepi.2013.04.008).

    Demouchy, S., Jacobsen, S.D., Gaillard, F., Stern C.R., (2006). Rapid magma ascent recorded by water diffusion profiles in mantle olivine. Geology, 34 : 429-432.

    Demouchy, S., Mackwell S. (2003). Water diffusion in synthetic iron-free forsterite. Phys. Chem. Minerals. 30:786-794.


    Collaborations (top 10):

    Samae V., Cordier, C., Demouchy, S., Bollinger C., Gasc, J., Koizumi S., Mussi A., Schryvers, D., and Idrissi H., (2021) Stress-induced amorphization triggers deformation in the lithospheric mantle. Nature. 591, 82-86.

    Delon R., Demouchy, S., Marrocchi Y., Bouhifd, M.A., Gasc J., Cordier P., Koizumi S., & Burnard. P.A., (2020) Effect of deformation on helium storage and diffusion in polycrystalline olivine. Geochim. Cosmochim. Acta.

    Gasc, J., Demouchy, S., Barou F., Koizumi, S., and Cordier, P. (2019) Creep mechanisms in the lithospheric mantle Inferred from deformation of iron-free forsterite aggregates at 900-1200 °C, Tectonophysics, 761, 16-30,

    Thieme, M., Demouchy, S., Mainprice, D., Barou, F., Cordier,. P. (2018) Stress evolution and associated microstructure during transient creep of olivine at 1000-1200 °C, Phys. Earth Planet. Int., doi: 10.1016/j.pepi.2018.03.002. (

    Thoraval, C., Demouchy, S., Padron-Navarta, J.-A., (2019) Relative diffusivities of hydrous defects from partially dehydrated natural olivine. Phys. Chem. Minerals. 46, 1-13, doi: 10.1007/s00269-018-0982-x

    Burnard P, Demouchy, S., *Delon R ., Arnaud N,. Marrocchi, Y., Cordier P, Addad A. (2015). The role of grain boundaries in the storage and transport of noble gases in the mantle. Earth Planet. Sci. Lett. 430, 260-270. doi: 10.1016/j.epsl.2015.08.024

    Mussi A. Cordier P., Demouchy, S., (2015). Characterization of dislocation interactions in olivine using electron tomography. Phil. Mag. 95(4), 335-345. doi:10.1080/14786435.2014.1000996.

    Denis, C.M.M, Demouchy, S., Alard, O. (2018) Heterogeneous hydrogen distribution in orthopyroxene from veined mantle peridotite (San Carlos, Arizona): Impact of melt-rock interactions. Lithos, doi:10.106/j.lithos.2018.01.007.

    Denis C.M.M., Demouchy, S., Shaw C.S.J., (2013). Evidence of dehydration in peridotites from Eifel Volcanic Field and estimates of magma ascent rates. J. Volcan. Geotherm. Res 258: 85-99 (doi: 10.1016/j.jvolgeores.2013.04.010).

    Cordier P., Demouchy, S., Beausir B., Taupin V., Barou F. & Fressengeas C. (2014). Disclinations provide the missing mechanism for deforming olivine-rich rocks in the mantle. Nature. 507:51-56. doi: 10.1038/nature13043.

    Rang A with LMV since 1 March 2022:

    [Publications nom=”Demouchy” prenom=”Sylvie” rang=”Rang A”]

    Rang B et C :

    [Publications nom=”Demouchy” prenom=”Sylvie” rang=”Rang B-C”]

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