Lithospheric structure in the Atlantic-Mediterranean transition zone (southern Spain, northern Morocco): a simple approach from regional elevation and geoid data

A new methodology for automatic modelling of crustal and lithospheric thickness or density variations that integrates both elevation and geoid anomalies is presented. We used this algorithm to image the main lithospheric heterogeneities within the Atlantic-Mediterranean transition zone. Main assumptions in the modelling are local isostasy and a two-layered model comprising crust and lithospheric mantle with constant densities, plus sea water and asthenosphere. The results show a wide zone of thickened lithosphere, oriented NE-SW and located beneath the western Betics and Rif, the Gulf of Cadiz and the northwestern Atlantic Moroccan margin. In addition, a zone of thinned lithosphere with the same orientation is shown beneath the Atlas Mountains and the eastern Alboran Basin.