Sylvie Demouchy, Director of Research at the CNRS, receives the SFMC’s Mid-Career Merit Award 2025.
Sylvie Demouchy is renowned for her work on hydrogen diffusivity in nominally anhydrous minerals in the mantle, particularly olivine. She has also demonstrated that hydrogen diffusivity in grain boundaries is not as rapid as previously thought, meaning that H-rich and H-poor heterogeneities in the mantle could persist over geological timescales. An important aspect of Sylvie’s career at Géoscience Montpellier has been the experimental study of the rheological properties of olivine, culminating in a new flow law that allows continuous modelling of upper mantle deformation, from the depths of the lithosphere to those of the asthenosphere, which is now used in geodynamic modelling. Finally, Sylvie demonstrated the existence of disclination in deformed olivine, rotational defects in the crystal lattice that had previously only been predicted theoretically in silicates. A geologist by training, she continues to analyse natural samples through her studies of xenoliths from the lithospheric mantle. In addition to her scientific achievements, Sylvie has trained many students. She is also recognised for her service to the national community (through the SFMC, Section 18 of the CNRS, the High Pressure Network, and the CSIT) and the international community (having served as secretary of the IMA, as well as her service to the MSA and the EMU).
Committee members: Liz Cottrell, Nadia Malaspina, Max Schmidt, George Calas, Hélène Bureau, Isabelle Daniel et Nathalie Bolfan-Casanova.
