Long‐Term Deformation in the Alpine‐Provence Foreland Constrained by In Situ Calcite U‐Pb Dating

Abstract The evolution of the Alpine‐Provence foreland is characterized by multiple deformation phases since the Mesozoic, representing successive compressional and extensional episodes. The precise timing and spatial evolution of these deformation phases remain poorly constrained due to the lack of absolute geochronological data. Here, we present U–Pb dating and stable isotope analysis (δ 18 O and δ 13 C) of calcite associated with brittle deformation in the sedimentary cover between the Vercors and Vaucluse massifs in south‐eastern France. Combined with paleostress reconstructions, the results allow to refine the dynamics of deformation across the Alpine‐Provence foreland. Our results indicate that North‐South compression, related to the Pyrenean orogeny, is recorded since ca. 92 Ma. Combined with previously published U–Pb data from SE France, these results support the existence of a regional‐scale compressive phase affecting the sedimentary cover during the Upper Cretaceous, and predating the commonly accepted onset of Pyrenean shortening based on global‐scale reconstruction (∼84 Ma). A second, Paleogene, deformation pulse is also related to the Pyrenean orogeny. During the Oligocene, E‐W extension is associated with the development of the West‐European Rift System, highlighted by ages of ca. 33 Ma in the Vocontian basin and ca. 25 Ma in the Vaucluse. Finally, Alpine E‐W compression reactivated pre‐existing faults ca. 22 Ma onward. This age is structurally linked to the formation of the foreland fold‐and‐thrust belt in response to the exhumation of the external crystalline massifs related to a thick‐skinned deformation mode. The stable isotope data indicate the preservation of a primary isotopic signature in the dated calcites.