Structural evolution of the Pyrenees: tectonic inheritance and flexural behaviour in the continental crust

Abstract

The ECORS deep seismic reflection profile and additional geological data are used to understand deformation processes in the Pyrenees. The middle crust shows two major sets of seismic reflectors, interpreted as Hercynian structures. During Permian and the Late Jurassic-Early Cretaceous rifting events, these structures were extensionally reactivated (mainly within the European plate). During the Pyrenean orogeny, tectonic inversion of the Early Cretaceous basins took place located mainly on the European plate) and Hercynian southward-directed verging thrusts were also reactivated in the Iberian foreland. A regional model is proposed which takes into account the lithospheric flexure and the evolution of the sedimentary load. This study shows the different rigidities of the European and Iberian plates (difference related to differential thinning events) as well as an east-west diachronism of the flexure for the European plate and unflexing behaviour after the orogeny.