Numerical modelling of physical processes involved in the recycling of the lithosphere
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AuthorGea Jódar, Pedro José
DepartamentoUniversidad de Granada. Departamento de Física Teórica y del Cosmos
SponsorshipMáster en Física. Universidad de Granada
The origin and tectonic evolution of the Western Mediterranean region, specifically the Gibraltar Arc system, is the result of a complex geodynamic evolution involving the convergence of the Eurasia and Africa plates and the dynamic impact of the subducted body observed in tomographic studies beneath this region, known as the Rif-Gibraltar-Betic (RGB) slab. Although geologic and geophysical data collected in the last few years have greatly increased our knowledge of the Gibraltar Arc region, it is still unclear the mechanical links between the Gibraltar slab and the past deformation of the overriding Alboran lithosphere as well as present-day motion shown in detailed GPS observations. In this work, we use the open source code ASPECT to model the geodynamic evolution of the RGB slab in 2D over the last 20 Myr. The initial model setup simulates a vertical WE section at a latitude of about 36 N and represents the situation at about 20 Ma. We conduct a parametric study varying the rheological parameters and the initial slab geometry parameters (dip angle and length) to properly fit the robust current slab features, particularly, its position and its curved morphology extending eastward in depth. We show how after 20 Myr of model evolution, i.e. at present time, the slab pull appears to have a still significant influence on surface velocities. We find a westward surface motion caused by the negative buoyancy of the slab. These velocities increase westwards from 1 to 4 mm/yr along the profile, consistently with geodetic observations. We also study the effects of different model parameters on the dynamics of the RGB slab.