Abstract. The Vocontian Basin in southeastern France records a long-lived history of subsidence and polyphase deformation at the junction of Alpine and Pyrenean orogenic systems. This study aims to reconstructed the geodynamical evolution of this basin, based on new U–Pb dating of calcite from veins and faults combined with RSCM thermometry and stratigraphy-based burial models. Three main generations of calcites are dated: (1) Late Cretaceous to Paleocene dates related to Pyrenean-Provençal convergence (~84–50 Ma); (2) Oligocene dates linked to the West European Rift extension (~30–24 Ma); and (3) Miocene dates ascribed to strike-slip and compression associated with Alpine collision (~12–7 Ma). No older ages related to the Jurassic and Early Cretaceous rifting phases are obtained suggesting limited syn-rift fluid circulation or subsequent dissolution of early calcite mineralization. RSCM data highlight a pronounced E–W thermal gradient, with peak temperatures exceeding 250 °C in the eastern basin, consistent with crustal thinning and/or salt diapirism. These results emphasize the large-scale impact of the opening of the West European Rift in SE France and underscore the possible mismatch between the large-scale tectonics and the tectonic history inferred from calcite U–Pb dating, which is sensible to presence of fluids and the physical conditions for their preservations.
Boschetti et al. (Mon,) studied this question.