Geodynamic inversion to explain the present-day plate motion in the Alpine-Mediterranean area

The Alpine-Mediterranean region is area of interest for many studies seeking to better understand the geological evolution as well as the present-day mantle and lithosphere structure. However, despite numerous studies, the geological structure of the upper mantle and the geometry of the different subduction zones remain matter of debate.

Here, we use 3D geodynamic models to investigate the impact of the structure and material properties of the upper mantle and lithosphere on the motion of the Alpine-Mediterranean area. The geodynamic simulations are performed by the finite-difference code LaMEM (Kaus et al. (2016)) and a visco-plastic rheology is used to explore the dynamic behaviour of the upper mantle. In particular, we use the recently developed Julia interface to LaMEM to start simulations and read back the results which simplifies postprocessing and comparing the results to observational constraints.

Specifically, we compare the models with recently compiled GPS velocity data (Serpelloni at al. (2022)). As a result of the geological history in the Mediterranean the density and viscosity structure of the upper mantle is rather complex and influenced by various subduction zones, such that geometry, viscosity and density structures are primary parameters of interest in this study.

First results suggest that the Calabria subduction and the Hellenic subduction explain the fastest horizontal velocities in the Mediterranean whereas the horizontal motion in the Alpine area cannot arise from an active subduction zone but rather from large density and viscosity differences caused by the remnants of older subduction zones.

 

Kaus B J P, Popov A A, Baumann T S, Pusok A E, Bauville A, Fernandez N, and Collignon M (2016): Forward and inverse modelling of lithospheric deformation on geological timescales. Proceedings of NIC Symposium.

Serpelloni E, Cavaliere A, Martelli L, Pintori F, Anderlini L, Borghi A, Randazzo D, Bruni S, Devoti R, Perfetti P and Cacciaguerra S (2022): Surface Velocities and Strain-Rates in the Euro-Mediterranean Region From Massive GPS Data Processing. Front. Earth Sci. 10:907897. doi: 10.3389/feart.2022.907897