Profil de muriel gerbault
Email : gerbaultSPAMFILTER@get.obs-mip.fr
Téléphone / phone: 0561332653
Bureau / office : F154
Institution : IRD
Statut / status: Chercheur
• Academic Researcher at IRD (Institut de Recherche pour le Développement, "Chargé de Recherche")
- Since 2015: GET, Toulouse, France.
- 2008-2014: Geoazur, Sophia-Antipolis, France.
- 2004-2008: Universidad de Chile, Santiago, Chile.
- 2002-2004: LMTG, Toulouse, France.
• 2001-2002: PostDoc fellowship at Vrije Universiteit, Amsterdamwith ISES program: thermo-mechanical modeling of continental convergence,
• 1999-2001: Post-Doctoral contract with IGNS (Institute of Geological and Nuclear Sciences),>SIGHT project, New Zealand:thermomechanical modeling of the Southern Alps.
• 1999: PhD at the Lab. Geophys. Tectonics, University of Montpellier II, France:Numerical models of localised deformation at the lithospheric scale.
I mainly use numerical methods to test and validate geodynamical scenarii that involve the role of elasto-visco-plastic rheologies to produce specific tectonic structures. Sometimes, these applications require algorithmic implementation. I seek to compare modeled features of deformation to different types of data from structural geology and geophysics, at the scales of thrust nappes and lithospheres. I like to show the importance of a dynamical stress evolution as opposed to simple kinematical concepts.
PAST: I started with applying the theory of non-associated elasto-plasticity to reproduce the progressive localisation of deformation at the crustal and lithospheric scale, with special emphasis on the co-development of periodic buckling and faulting in intra-plate domains. I've studied mountain building in the New-Zealand Southern Alps, understanding the link between surface processes, brittle deformation in the upper crust and 2D and 3D lateral flow in the lower crust (Gerbault et al., 2002, 2003). I also studied lateral flow of orogenic crust in continental orogenies (Gerbault & Willingshoffer, 2003) and along-strike Andean orogenic flow (Gerbault et al., 2005). I looked at the importance of spatially variable strength contrasts in the oceanic and continental lithospheres to explain the variable morphology of the Chilean Andes, where similar kinematic boundaries produce contrasting features such as the extremely thick Altiplano lithosphere (~19°S) and the flat subduction area (~31.5°S) (Dorbath et al., 2008, Gerbault et al., 2009, Marot et al., 2014).
We've also explored periodic variations in stress regime in the overriding plate induced by the folding interaction of a subducting plate with the 660 km depth mantle transition zone (Cerpa et al., 2014,2015).
RECENTLY, I studied modes of exhumation of lower crustal rocks in warm orogens such as in Western Africa (2 Gy, Ganne et al., 2014) and in the Maures Massif (Variscan belt, Gerbault et al., 2017). Compression leads to burrial and heating, triggering partial melting and production of light material, which in turn generates gravitational instabilities in the core of crustal roots and during ongoing convergence. Depending on the relative strength of the surrounding layers and the speed of convergence, light molten crust may either flow upwards and form diapiric domes intruding the upper crust, or flow laterally in opposite direction to convergence, participating in widening/equilibration of the orogenic domain. Internal heat sources trigger partial melting and exhumation within about 20 Myrs.
Current projects focus on such diapiric exhumation in 3D, considering a stage of active convection of partially molten orogenic crust (Naxos case, Vanderhaeghe et al;, 2018), in collaboration with the Fluid Mechanics Institute in Toulouse (IMFT, PHD Aurélie Louis-Napoléon with Thomas Bonometti).
I am also interested in the mechanical state of magmatic chambers embedded in the crust. I have worked on showing the role of depth-dependent failure on the internal state of pressure of a magmatic chamber and the associated patterns of elastic and brittle deformation propagating to the surface (shear vs. tensile failure, Gerbault et al., 2012). 3D models have just been published (Gerbault et al., 2018) and allow to show that while shear failure develops at orders of magnitudes of overpressure depending on the oblate/prolate geometry of a chamber, the development of elasto-plastic diffuse zones of dilation shall also control the percolation/migraiton of magmatic fluids through the crust.
I am presently involved in applying quantitative models to seismo-volcanic areas in Southern Chile, in collaboration with the Univeristy of Concepcion (UDEC, PHD Camila Novoa Lizama with Andres Tassara) and Dominique Rémy (GET), cf. Lizama et al. (submitted).
Finally, i also study in collaboration with M. Rabinowicz (GET), the thermo-mechanical interaction of a lithosphere and a plume in terms of stress field control on the migration of deep magmas towards the surface, in oceanic (eg. Yellowstone - Rigo et al., 2015; La Réunion, collab. F. Fontaine, IPGP, Gerbault et al., 2017), and continental contexts (eg. northern Africa, Iranian plateau, Mohammadi et al.., J.Petrol, accepted).
- Ganne, J., Gerbault, M., & Block, S. Thermo-mechanical modeling of lower crust exhumation—Constraints from the metamorphic record of the Palaeoproterozoic Eburnean orogeny, West African Craton.Precambrian Research,243, 88-109, 2014.
- Marot, M., Monfret, T., Gerbault, M., Nolet, G., Ranalli, G., & Pardo, M. Flat versus normal subduction zones: a comparison based on 3-D regional traveltime tomography and petrological modelling of central Chile and western Argentina (29°–35° S)."Geophysical Journal International 199.3, 1633-1654, 2014.
- Cerpa, N. G., Araya, R., Gerbault, M., & Hassani, R. (2015). Relationship between slab dip and topography segmentation in an oblique subduction zone: Insights from numerical modeling. Geophysical Research Letters, 42(14), 5786-5795.
- Rigo, A., Adam, C., Grégoire, M., Gerbault, M., Meyer, R., Rabinowicz, M., Fontaine F.J., Bonvalot, S. (2015). Insights for the melt migration, the volcanic activity and the ultrafast lithosphere delamination related to the Yellowstone plume (Western USA). Geophysical Journal International, 203(2), 1274-1301.
- Contreras, M., Tassara, A., Gerbault, M., Araya, R., & Bataille, K. (2016). Interseismic deformation at subduction zones investigated by 2D numerical modeling: case study before the 2010 Maule earthquake. Andean Geology, 43(3), 247-262.
- Gerbault M., Schneider J. Reverso-Peila A., Corsini M., Exhumation of orogenic lower crust during ongoing compression in Maures Massif, France: geological synthesis and thermo-mechanical models, Tectonophysics 2016.
- Gerbault M., Fontaine F., Rabinowicz M., Bystricky M., Elastic flexure above mantle plumes explains the upstream offset of La reunion and Hawaii volcanic Islands. Earth and Planetary Science Letters, 2017.
- Gerbault, M., Hassani, R., Lizama, C. N., & Souche, A. (2018). Three‐Dimensional Failure Patterns Around an Inflating Magmatic Chamber. Geochemistry, Geophysics, Geosystems.
- Vanderhaeghe, O., Kruckenberg, S. C., Gerbault, M., Martin, L., Duchêne, S., & Deloule, E. (2018). Crustal-scale convection and diapiric upwelling of a partially molten orogenic root (Naxos dome, Greece).Tectonophysics.
Teaching : - thermomechanics and fluid flow in volcanic and tectonic settings (masters level, 15 hours) 2014-2018
- thermics, gravimetry, electromagnetism (licence 2, 30 hours) 2011-2013
- thermo-mechanical numerical modeling (masters level, 30 hours) 2003-2014
- thermomechanics and planetary tectonics (masters level, 20 hours) 2011-2013
Co-Supervision of 10 Masters and 4 PhD.