Gravity modeling reveals a Messinian foredeep depocenter beneath the intermontane Fucino Basin (Central Apennines)

Residual gravity anomalies over Central Italy clearly indicate a prominent regional minimum over the Fucino Basin. Here, we forward model this anomaly along seven cross-sections. The modeling results validate the geometries and petrophysical properties of the Plio-Quaternary units previously proposed by reflection seismic data interpretation. Moreover, we suggest that a thick wedge-shaped sequence is present beneath the Plio-Quaternary post-orogenic units. Based on the inferred density and velocity properties, as well as outcrop evidence from around the Fucino Basin, this sequence would likely represent thick (similar to 1700 m) siliciclastic syn-orogenic Messinian foredeep deposits. The proposed model implies a long-lasting tectonic inheritance history for the Fucino area, which originally hosted primary paleogeographic Mesozoic-Miocene boundaries. In the Messinian-Recent time, the Fucino has continuously represented a first-order tectonic depocenter for siliciclastic sediments, despite differences in tectonic regime (syn-orogenic Messinian, post-orogenic Plio-Quaternary) and palaeoenvironments (Messinian marine flysch, Plio-Quaternary alluvial-lacustrine facies). The compaction-corrected sedimentation rate (similar to 0.89 mm yr(-1)), suggests a foredeep activity possibly spanning the entire pre-evaporitic, evaporitic and post-evaporitic Messinian time and is comparable to the sedimentation rate observed in the larger Pliocene Apennine foredeep, similar to 100 km northeast of the study area, suggesting a self-similarity of the beltforeland system across time and space.