The palynology of the Lower Cretaceous (Barremian-Aptian transition) from the Gorgo a Cerbara section, Northern Apennines, Central Italy

The Gorgo a Cerbara section, located in the Umbria–Marche Apennines (Italy), represents a key stratigraphic reference section for the Lower Cretaceous (Barremian–Aptian transition) within the Tethyan domain. This 33.06 m thick succession spans the upper Maiolica and lower Marne a Fucoidi formations and includes the Selli Level, the sedimentary expression of the early Aptian Oceanic Anoxic Event 1a (OAE1a). A 6 m thick interval comprising the uppermost Maiolica and lowermost Marne a Fucoidi formations, including the Selli Level, was analyzed for its palynological content. The recovered assemblages are dominated by terrestrial miospores with subordinate marine elements (dinoflagellate cysts and acritarchs). The upper Maiolica Formation yielded abundant Druggidium deflandrei, Cassiculosphaeridia reticulata, and Pterodinium spp., alongside the first occurrence of Odontochitina operculata and the acritarch Pinocchiodinium erbae. The angiosperm pollen Afropollis cf. jardinus was identified below and within the Selli Level, indicating its earliest Aptian distribution. Palynological recovery sharply decreases in the overlying Marne a Fucoidi Formation, with sparse, poorly preserved dinoflagellate cysts and spores. Comparison with coeval Tethyan sections (Angles, La Bédoule, Cismon, Río Argos) reveals close similarity in palynological composition and key biostratigraphic events. The last occurrence of D. deflandrei near the top of magnetochron M0r and the first occurrence of O. operculata define the Barremian–Aptian boundary interval. The appearance of Afropollis cf. jardinus in the uppermost Maiolica Formation marks one of the earliest records of angiosperms in the Tethyan realm. Overall, the integrated palynological data refine the biostratigraphic framework of the Gorgo a Cerbara section, improving its chronostratigraphic calibration and reinforcing its status as a regional reference for the late Barremian–early Aptian transition across the Umbria–Marche Basin.