Modelización numérica de procesos de delaminación asimétrica y remoción convectiva: comparación con modelos de evolución del mar de Alborán

Abstract

Different conceptual models for the formation of the Alboran Sea have been proposed to date. These models are based on different mechanisms to explain the presence of extension within a regional context of compression between Africa and Eurasia. In this study we have developed a numerical algorithm for thermo-mechanical modelling to evaluate in a quantitative and comparative way two of the main proposed mechanisms: the «in situ» convective removal of a lithospheric root, and the laterally propagating asymmetric delamination of lithospheric mantle. Our results show that the first mechanism does not produce any lithospheric or crustal significant thinning, whereas the delamination mechanisms is shown to successfully reproduce first order features of the Alboran Sea and surrounding zones: the thinning/thickening distribution, the occurrence of intermediate depth seismicity and the upper mantle structure imaged by seismic tomography. The lower crust is shown to be able to reach depths of 100-150 km in some narrow areas, due to the mechanically-driven viscous drag of the downwelling mantle.