As part of the DIAS geo-seminar series, Dr Andréa Tommasi (Université Montpellier) will be presenting: Memory in plate tectonics: the role of deformation-induced anisotropy of physical properties in the mantle.Abstract:
The major challenge in modelling the dynamics of the solid Earth is to reproduce the extremely heterogeneous deformation of the outer layer of the planet – plate tectonics - in response to the continuous motion that animates the underlying convective mantle. An additional difficulty is to simulate the repeated reactivation of some plate boundaries, first noticed by Wilson in 1966, since this 'memory' implies preservation of variations in the mechanical behavior of the plates for time spans of hundreds of million years. In this talk I will discuss how anisotropy of mechanical properties due to preferred orientation of olivine crystals in the mantle might account for this memory. I will recall how this anisotropy forms in response to mantle deformation and show models that test its potential for producing tectonic reactivation at the plate tectonics scale.