Geophysical knowledge of Iberia; existing results and open questions

Abstract:

The dimensions, the geographical position and the complex geological history of the Iberian Peninsula makes it a unique and singular target to study its lithospheric structure using geophysical methods. The lithospheric structure beneath Iberia is being investigated since the 1970s using deep multichannel seismic reflection and refraction/wide-angle reflection profiling. Gravimetric and magnetic anomalies maps were developed following the deployment of permanent and temporary stations, mostly during the 90s. Later on, the progressive use of Global Navigation Satellite Systems (GNSS) instruments contributed to monitor the present-day motions within Iberia. During the last decade, numerous geological and geophysical surveys have investigated the Iberian lithosphere in the onshore and offshore regions , the most recent ones related to the TopoIberia project.

Our objective here is twofold. Firstly, we want to summarize the available geophysical information over the area, from the upper crust to the Lithosphere-Asthenosphere Boundary (LAB), the dynamics of the upper mantle, and the structure of the 440-670 km discontinuities. Results arising from GNSS data, potential fields, controlled source seismic profiles, magnetotelurics, body and surface wave tomography, receiver functions and 2D and 3D lithospheric modeling will be reviewed and compared. Secondly, we will focus on the areas of greater geodynamical interest and the regions where inconsistencies within the geophysical results, or contradictions in their geological interpretation, have been detected, trying to identify the major questions that are still under debate.

Besides shedding light to the state of knowledge and pointing out present-day research challenges, this compilation aims to provide a valuable tool to integrate with the geological and geodynamical processes that built Iberia, surrounded by oceanic lithosphere of Jurassic-Cretaceous, Early Cretaceous and Oligocene ages, bounded by the Pyrenean and Betics plate boundaries, and modified by the Cenozoic Western Mediterranean evolution.

This research has been partially funded by the Generalitat de Catalunya grant 2017SGR1022.