Late Variscan deformation in the Iberian Peninsula; a late feature in the Laurentia–Gondwana dextral collision

The Late Variscan deformation event in Iberia is characterized by an intraplate deformation regime induced by the dextral oblique collision between Laurentia and Gondwana. This episode in Iberia is characterized by NNE–SSW brittle to brittle–ductile strike-slip faults, which are considered by the classic works as sinistral strike-slip faults. However, the absence of Mesozoic formations constraining the age of this sinistral kinematics led some authors to consider it as the result of Alpine reworking. Structural studies in Almograve and Ponta Ruiva sectors (SW Portugal) show that NNE–SSW faults have a sinistral kinematics and are occasionally associated with E–W dextral shears. Moreover, this kinematics is related to the late deformation episodes of Variscan orogeny. In Almograve sector, the Late Variscan structures are characterized by NNE–SSW sinistral kink bands, spatially associated with E–W dextral faults. These structures are contemporaneous and affect the previously deformed Carboniferous units. The Ponta Ruiva Sector constrains the age of deformation because the E–W dextral shears affect the Late Carboniferous (late Moscovian) units, but not the overlying Triassic series. The new data show that the NNE–SSW and the E–W faults are dynamically associated and result from the Late Variscan deformation episode. The NNE–SSW sinistral faults could be considered as second-order domino structures related to first-order E–W dextral shears, linked to Laurentia–Gondwana collision during Late Carboniferous–Permian times.