Calcareous nannofossil biostratigraphy of the Antola Unit succession (Northern Apennines, Italy): new age constraints for the Late Cretaceous Helminthoid Flysch.

The stratigraphic succession of the Helminthoid Flysch Antola Unit of the Northern Apennines has been dated through the analysis of the calcareous nannofossil assemblages. The results of this study indicate that the Antola Unit succession comprises the Late Cenomanian-Early Turonian (UC5-UC7 Nannofossil Zones) Montoggio Shale, the Early Campanian (UC14b, UC15b Zones) Gorreto Sandstone, the upper Early Campanian-Early Maastrichtian (from UC15b/15c to UC17 Zones) Mt. Antola Flysch, the Early Maastrichtian-lower Late Maastrichtian (UC18-UC19 Zones) Bruggi-Selvapiana Formation and the Late Maastrichtian-Late Paleocene (from UC20a to NP5 Zones) Pagliaro Shale. These data suggest a possible correlation with the Cassio Unit succession, another Helminthoid Flysch unit of the Northern Apennines. The data provide a useful contribution to the knowledge of the tectono-sedimentary evolution of Helminthoid Flysch successions and to the reconstruction of the Late Cretaceous-Tertiary palaeogeography and tectonics of the Helminthoid Flysch Basin.