My research themes couple geodynamics and petrophysics:
- the relations between mantle flow and the anisotropy of its physical properties
- multi-scale numerical models of the development of olivine crystalographic orientations and seismic anisotropy in the upper mantle, which were applied to the study of:
- upper mantle deformation and seismic anisotropy due to the asthenospheric drag beneath an oceanic plate
- the effect of a continuous vertical variation of the LPO on the measured anisotropy as well as the frequency dependence of this later
- the deformation of the lithospheric (and sublithospheric) mantle in continental collision zones, rifts, subductions, and lithospheric-scale shear zones
- seismic anisotropy associated with salt diapirism
- numerical models and experimental measurements of the anisotropy of thermal diffusivity in the upper mantle
- strain-induced mechanical anisotropy in the upper mantle: effect of the preexisting structure of the lithosphere on plate tectonics
- relation between deformation and the anisotropy of electrical conductivity in the upper mantle inferred from long-period MT measurements
- flow and seismic anisotropy in the deep mantle (actualités INSU)
- the feedbacks between deformation and fluids or melts in the mantle by analysing natural systems such as:
- the relations between reactive melt percolation leading to refertilization and deformation in the Lherz peridotite (actualités INSU), in Ronda, and in the Ethiopian rift
- the deformation-induced melt segregation in Oman and Lanzo
- the effects of hydrous melts and of the crystallization of hydrous phases on the peridotites' rheology in Finero
- the interactions between plate tectonics and mantle convection :
- Between 2009-2013 I coordinated the EC Marie Curie Initial Training Network CRYSTAL2PLATE - a training and career development platform associating 7 European research teams internationally recognized for their excellence in in Geodynamics, Petrophysics, Geochemistry, Petrology, Fluid Mechanics and Seismology. It reunited 10 PhD students and 2 postdocs whose projects focused on various aspects of the question: How does plate tectonics actually work? The CRYSTAL2PLATE Initial Training Network studied the interactions between lithospheric plates and the convecting mantle, analyzing (1) how plates modify or are affected by convection, (2) the role of the preexisting structure of the plates on the deformation distribution, (3) the coupling between chemical and physical processes at various scales in the mantle... These studies led to the publication of >20 articles (see the project publications list).
- In April 2016 we started a new EC Marie Sklodowska-Curie Innovative Training Network CREEP (Complex RhEologies in Earth and industrial Processes) . CREEP associates 10 European research teams and 10 industrial partners. It provides training to 16 early stage researchers (PhD students) via a cross-disciplinary collaborative research program focused on the complex mechanical behaviour of Earth materials and their implications for geodynamic or industrial processes. These PhD projects cover a large spectra of applications of complex rheologies, from the deformation of the Earth surface and deep layers, to geothermal and petroleum exploration and industrial processes.
- the elementary processes resulting in strain heterogeneity and controlling recrystallization during viscoplastic (ductile) deformation :
- In the frame of the ANR DREAM (2014-2018) and of the EU FP7-IEF project InSiDe-Strain we associate the in-situ characterization by EBSD of the microstructure and texture (CPO) evolution during annealing and deformation experiments in the SEM Crystal Probe on analog materials (hexagonal ice and magnesium polycrystals) and numerical modelling of the viscoplastic deformation heterogeneity and of the recrystallization processes at the crystal and aggregate scales. This study is carried in collaboration with colleagues from Glaciology (IGE Grenoble) and Materials Sciences (LEM3 Metz et CEMEF Sophia-Antipolis). (actualités INSU)
- This subject is also at the center of the activities of the CNRS INSIS-INSU Groupement de Recherches (GDR) Recristallisation et croissance des grains , which reunites academic and industrial researchers working on recrystallization phenomena from the Material and Earth Sciences communities in France.
In addition, in a not so far away past (at least I would like to believe!), I have also worked on:
- the effect of thermally-induced intraplate rheological heterogeneities on the mechanical behavior of a continental plate submitted to compression (continental collision) through the analysis of field examples (Neoproterozoic collisional belts of Brazil) and finite-element models;
- the relationship between magmatism and deformation in the continental crust: coupling between granites emplacement and development of lithospheric scale strike-slip shear zones;
- the partioning of the deformation in continental collisional belts: kinematic analysis of a neoproterozoic collisional belt of southern Brazil (field mapping and microstructural studies) showing a temporal and spatial partitioning of the deformation between tangential and strike-slip shear zones.