Initial results of modelling 3D plate dynamics in the Alpine-Mediterranean area

Tectonic reconstructions of lithospheric plate motion can be approached by different geological methods. However hypotheses derived from these findings are often not validated in a physically consistent manner. Therefore we employ 3D geodynamic modelling in order to test geological reconstructions.

In this work, 3D thermomechanical forward simulations of the Alpine-Mediterranean area are conducted using the software LaMEM (Kaus et al. (2016)). A viscoelastoplastic rheology and an internal free surface are applied, which means that apart from the internal dynamics also the surface response can be investigated. Kinematic reconstructions of Le Breton et al. (2021) at 35 Ma serve as an initial setup for the simulations. The goal of these simulations is to determine the main driving forces of plate dynamics in this area. This is done by evaluating effects of different model parameters such as the thermal structure and the geometry of the slabs, the viscosity of the mantle and brittle parameters of the crust.

The geodynamic behaviour of the Alpine-Mediterranean area is dominated by various subducting plates which makes it particularly difficult to distinguish the unique influence of different geodynamic processes. The Adriatic microplate plays a key role in the development of the Alpine Orogeny and its plate motion and therefore serves as a marker as it is possible to compare the current position of this plate with the simulation itself. Even though these forward simulations are not capable of exactly reconstructing the current tectonic setting, they provide insights into parameters which influence the subduction dynamics.

First results suggest that the plate motion of Adria is primarily driven by the interaction of the Calabria slab and the Hellenic slab and that the propagation of these slabs strongly depends on the slab geometry and the initial trench location. Furthermore the spreading rate of rifting in the Liguro-Provençal Basin massively affects the timing of Adria’s plate motion.

 

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

Le Breton, E., S. Brune, K. Ustaszewski, S. Zahirovic, M. Seton, R. D. Müller, 2021: Kinematics and extent of the Piemont–Liguria Basin–implications for subduction processes in the Alps. Solid Earth, 12(4), 885-913.