EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Mantle controls on geodynamic processes and their surface expressions: a global approach

Maëlis Arnould1, Antonio Manjón-Cabeza Córdoba2,3, and Tobias Rolf3,4
Maëlis Arnould et al.
  • 1Laboratoire de Géologie de Lyon (LGL-TPE), University Lyon 1, France
  • 2Andalusian Earth Sciences Institute (UGR-CSIC), University of Grenada, Spain
  • 3Centre for Earth Evolution and Dynamic (CEED), University of Oslo, Norway
  • 4Institute of Geophysics, University of Münster, Germany

It is well-established that the mantle exerts a strong control on the geodynamic processes and their expressions observed at the surface. One of the key components in mantle-surface interaction is rheology, yet, the details of this rheological coupling remain not well understood. This is particularly true for large to global scales, which are difficult to assess in the field or in the lab. For instance, rheological inheritance is thought to influence the onset location of plate boundaries and their subsequent evolution. But the originating physical processes and timescales over which such rheological inheritance applies are still debated. Moreover, differences in the rheological coupling between mantle and surface are expected to change first-order surface observables, such as topography.

Here, we use numerical geodynamic models of whole-mantle convection to test the sensitivity of surface tectonics to different rheological assumptions, for instance in terms of deformation mechanisms at play and rheological inheritance. We show that the self-consistent generation of plate tectonics from mantle convection is altered by the use of a composite rheology (with co-existing diffusion and dislocation creep), by the consideration of mantle grain-size evolution, as well as by simple parameterisations of rheological memory such as strain-weakening. Using a set of quantitative diagnostics, we also demonstrate how such rheological complexities affect surface topography.

How to cite: Arnould, M., Manjón-Cabeza Córdoba, A., and Rolf, T.: Mantle controls on geodynamic processes and their surface expressions: a global approach, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-6948,, 2023.