Iberian plate kinematics and Alpine collision in the Pyrenees

Abstract

With the aim to unravel first-order motions associated with the Alpine collisional history of the Pyrenees in SW Europe, we perform a plate-kinematic analysis of Iberia motion since the latest Mesozoic in a six-plate circuit. This analysis leads to reconstructions of the North Atlantic for the latest Cretaceous well in line with previous studies and supported by onland paleomagnetic data. Our study, moreover, shows that for each of the magnetic anomalies studied, a combination exists of total reconstruction poles for the different plates and plate fragments such that the modeled shortening values in the Pyrenees are in good agreement with the shortening values inferred from partially restored sections of the balanced ECORS Pyrenees profile. At the same time, the magnitude of the belt-averaged shear, i.e., the strike-slip component divided by the normal shortening, is predicted to be smaller than implicit in previous plate-kinematic studies, which seems consistent with the generally recognized thrust-belt nature of the Pyrenees. Our analysis yields a set of preferred total reconstruction poles for each of the plates and plate fragments. Using these poles, a net Africa–Iberia motion path is calculated that can be used as an independent constraint on the geodynamics of the western Mediterranean region.