Revealing the temporal dynamics of fault reactivation in the W-Alpine foreland using in-situ U−Pb dating on calcite

Long-term study of fault system activity is crucial for understanding the dynamics of orogeny structuring and the formation of peripheral basins, the impact of tectonic inheritance, seismic hazard assessment, and the estimating the coupling of deformation and erosion. At the junction of several orogenic domains, the foreland basin of the Western Alps exhibits a complex structural pattern inherited from the superposition of tectonic events since the late Paleozoic. Despite this knowledge, the absolute age of fault formation and reactivation remains poorly understood, primarily due to the difficulty of dating uranium-poor minerals typically found in sedimentary environments. This study proposes an integrated approach of structural analysis of deformations in the field combined to the recently developed U-Pb in-situ dating method on syn-tectonic calcite to fill this gap. By focusing on the subalpine massifs (from the Vaucluse massif to the Bornes massif), this work aims to constrain the dynamics of the Alpine foreland structuring over a wide temporal and spatial scale. Additionally, this study area presents diverse geodynamic characteristics, making it an ideal site to test the applicability of recent U-Pb in-situ dating methods.