Foraminifera diversity changes and paleoenvironmental analysis. The Lower Cretaceous shallow-water carbonates of San Lorenzello, Campanian Apennines, southern Italy.

A high-resolution stratigraphic study, carried out on the carbonate platform strata of the San Lorenzello section (Matese Mountains, southern Italy), Valanginian-Hauterivian in age, has allowed to: recognize lithofacies and their associations; assign the lithofacies associations to specific environments and individuate early meteoric diagenetic modifications, recurring at specific horizons. In this frame the vertical variation of benthic foram diversity has been analyzed. On the whole, foraminiferal genera diversity decreases from open to restricted marine environments. Moreover, a climatic control on carbonate sedimentation is suggested by a Milankovitch cyclicity organized in elementary cycles, bundles and superbundles as well as by diagenetic characteristics testifying that humid and arid conditions alternated during the Early Cretaceous times. The orbital cyclicity is also documented by foraminiferal diversity changes, even if some discrepancies between the lithofacies and the diversity locally occur. Therefore, the above diversity changes do not appear to provide sufficient information for the sequence-stratigraphic interpretation of shallow-water carbonates.