The transition from Pyrenean shortening to Gulf of Lion rifting in Languedoc (South France) – A tectonic-sedimentation analysis

The Pyrenean orogen extended eastward, across the present-day Gulf of Lion margin. late or post-orogenic dismantling this segment, contemporaneous with ongoing shortening in Spanish Pyrénées, is still debated. Understanding transition between two geodynamic events requires to document precise timing succession tectonic processes involved. We investigate superposition rifting structures over thrusts and folds onshore Languedoc. Compilation reassessment regional chronostratigraphy, light recent biostratigraphic dating new mapping Paleogene basins, lead date Priabonian. Tectonic-sedimentation relationship Eocene Oligocene depocentres are analysed surface exposures as well seismic reflection surveys. Bed-to bed allowed us to: i) characterise an intermediate sequence Priabonian age, bounded at base top by unconformities; ii) evidence syn-depositional deformation within Priabonian; iii) define axes deformation. Interpretation profiles, basins covered syn- post-rift sequences, reveals existence displaying similar features, that correlated Syn-depositional some correspond extensional structure, whereas neighbouring, reveal compressional distribution such apparently conflicting observations studied area provides for left-lateral strike-slip major faults (Cévennes Nîmes faults). Left-lateral along NE-trending accommodates E-W extension West European Rift (ECRIS) part N-S Central Western Pyrénées. clastic sedimentation Languedoc witness initial stages Languedoc-Provence prior Oligocene-Aquitanian back-arc rifting.