Jurassic Basin Architecture of the Foligno Mountains, Central Italy: Syn-Sedimentary Faulting and Facies Distribution

This study investigates the Jurassic successions of the Foligno Mountains by tracing tectono-sedimentary contacts across the study area, with particular attention to the relationships between pelagic deposits and the Calcare Massiccio carbonate platform substrate. It provides new constraints on the role of syn-sedimentary extensional faulting in the evolution of the Umbria-Marche Basin. The results reveal an organized network of normal faults interpreted as already active during the final stages of carbonate-platform development, based on the distribution of permanently subtidal facies. From the Sinemurian onward, minor depocenters developed between structural highs controlled by conjugate faults, accompanied by widespread pelagic sedimentation during the Pliensbachian. Fault-bounded paleo-escarpments and condensed successions record the persistence of bathymetric relief into the Middle and Upper Jurassic, with progressive attenuation of these reliefs and the expansion of basinal deposits onto the paleo-escarpments. The results better support an organized extensional framework than a chaotic fault pattern mainly related to Triassic evaporite flow or halokinesis.