Geodynamic implications for the formation of the Betic-Rif orogen from magnetotelluric studies

Abstract

Magnetotelluric data from the central Betics mountains (Spain) have been used to determine the electrical resistivity of the crust after a three‐dimensional (3D) interpretive approach. At shallow levels (<2 km), the resulting model shows good correlation between the geoelectric structures and the geologic units. At greater depths (>3 km), the most striking and well‐resolved feature of the model is an upper‐middle crust conductive body, located at the core of the Internal Betics antiform. This approximately 14‐km‐thick body is interpreted as basic or ultrabasic rocks containing a conducting mineral phase. Its structural location above the sole thrust of the Betic orogen and beneath the Nevado‐Filábride complex confirms the presence of a major suture zone between this complex and the autochthonous Iberian plate. This suture may correspond to an ancient oceanic or transitional domain developed between Iberia and the Alboran Domain during the opening of the Tethys Ocean, partially subducted and closed during the development of the Betic orogen. The possible geodynamic scenarios for the Betics have been reconsidered, taking into account this new constraint.