Palaeoenvironmental reconstruction of the Mio-Pliocene succession of the Miscano River: insights on sedimentation after the Messinian salinity crisis in the southern Apennines

We present a study of a Mio-Pliocene marine to a continental clastic sedimentary succession of the southern Apennines Foreland Basin System well exposed in the Miscano River in the Irpinia sector of the chain. These well-bedded wedge-top basin deposits host a significant angular unconformity between a post-evaporitic succession (uppermost Messinian-lowermost Pliocene), developed on top of the evaporite deposits related to the Messinian Salinity Crisis, and an overlying upper part of the Zanclean sediments. The unconformity witnesses a major tectonic shortening stage of the southern Apennines characterized by out-of-sequence thrusting that involved the Mio-Pliocene wedge-top basin deposits. Meio-microfaunal and nannofloral fossil assemblages were analyzed to define the depositional environments and biostratigraphy of the two successions. In addition, benthic foraminiferal and ostracod assemblages were studied in detail, and their autochthonous/allochthonous provenience was discussed from a paleoecological point of view. The relative response of these assemblages to environmental parameters, such as salinity, oxygenation, paleobathymetry and climatic changes, allowed us to reconstruct the paleoenvironmental evolution of these wedge-top basin deposits.