Plate kinematics in the Cantabrian domain of the Pyrenean orogen

Abstract

The Cantabrian domain represents the western portion of the Pyrenean orogen, in the area where the Iberian continental lithosphere was subducted toward the north underneath the transitional to oceanic lithosphere of the Bay of Biscay. There, the about 100 km of orogenic convergence have been mostly accommodated in the northern portion of the orogen (i.e. the retro wedge) developed in the Bay of Biscay abyssal plain, while only crustal-scale folding with limited internal deformation occurred in the Cantabrian southern wedge (pro-wedge). Integrated meso- and macrostructural analyses and a reappraisal of available information from the transitional area between the Pyrenean and Cantabrian domains are presented in this work, allowing to set geometric and kinematic constraints on the entire Meso-Cenozoic history of the northern portion of the Iberian Plate, including subduction initiation and evolution in the western portion of the Pyrenean orogen. <br><br> The structural record of the Late Jurassic to Early Cretaceous deformation stage, which was associated with rifting and seafloor spreading in the Bay of Biscay, indicates a ridge perpendicular (NNE-SSW oriented) extension, with no evidence of relevant strike-slip components during rifting. A Cenozoic NNW-SSE oriented shortening stage followed, related to the limited (about 100 km) north-directed subduction of the Iberian continental lithosphere underneath the transitional to oceanic lithosphere of the Bay of Biscay. Subduction led to the formation of the poorly-developed Cantabrian pro-wedge, which is laterally juxtaposed to the well-developed Pyrenean pro-wedge to the east. During this convergence stage, the structural framework in the Cantabrian pro-wedge, and particularly along its transition with the Pyrenean wedge to the east, was severely complicated by the reactivation of Paleozoic and Mesozoic inherited structures. <br><br> Data presented in this work fully support the development of the Cantabrian Mountains as related to indentation and consequent thickening of the Bay of Biscay transitional lower crust during north-directed subduction of Iberian continental lithosphere. In essence, the Cantabrian pro-wedge is a lithospheric south-verging fault-propagation anticline developing above the subduction plane. The structural record in the area indicates that a lithospheric fault-propagation folding stage was predated, during the very early stages of orogenic shortening, by the development of a lithospheric-scale open syncline overlying the nucleation point of lithosphere sinking. Such a syncline is today partially preserved and represents one of the few natural examples of subduction initiation

A decoupled kinematic model for active normal faults: Insights from the 1980, MS = 6.9 Irpinia earthquake, southern Italy

“…As such, they are capable of nucleating large earthquakes as a result of late Quaternary extensional reactivation. With this respect, the soft-linked, "immature" fault system mapped in the study area probably results not only from the young age of postorogenic extension, but also from the decoupling effect (e.g., Vendeville et al, 1987;Allemand and Brun, 1991;Richard and Krantz, 1991;Tavani, 2012) of the ductile level separating the shallow allochthonous multilayer from the deeper Apulian Platform carbonates and faulted basement.…”

Finite element modelling of stress field perturbations and interseismic crustal deformation in the Val d'Agri region, southern Apennines, Italy

“…ACCEPTED MANUSCRIPT 22 and Brun, 1991;Richard and Krantz, 1991;Tavani, 2012;Vendeville et al, 1987) of the thick ductile zone separating the shallow rigid lid from the faulted buried Apulian Platform carbonates and underlying basement. It is worth noting that the interpretation proposed in this paper is not in contrast with that implying an interaction between the Alta Val d'Agri best fitting all available constraints (Fig.…”

Formation and deformation of hyperextended rift systems: Insights from rift domain mapping in the Bay of Biscay-Pyrenees

“…A major break occurred in Aptian time [ Olivet , ] as a result of the counterclockwise rotation of Iberia [ Gong et al , ; Jammes et al , , ]. As a consequence of this rotation, a NNE‐SSW to NE‐SW extension is initiated in rift basins preserved onshore [ Jammes et al , ; Lagabrielle et al , ; Roca et al , ; Tavani , ] as emphasized by the NE‐SW segmentation observed (e.g., Pamplona, Toulouse, and Cevennes faults). These NE‐SW transfer faults cross the Iberian‐European plate boundary and are locally sealed by Albian sediments (Pamplona fault, between the Basque‐Cantabrian and Arzacq‐Mauléon basins [ Razin , ; Claude , ]).…”