Carbonate ecosystem and environmental evolution during the Valanginian–Barremian: Discussion on possible controlling factors in the Apennine Carbonate Platform record (Italy)

Shallow-water carbonate records are often characterised by low stratigraphic resolution and poor chronostratigraphic calibration despite abundant and diversified fossil content. We present here a stratigraphic study of a Valanginian–Barremian carbonate platform section, exposed in the southern Apennines (Italy). In the San Lorenzello section, we produced a high-resolution dataset integrating sedimentology, biostratigraphy, cyclostratigraphy and sequence stratigraphy to investigate how neritic biofacies responded to palaeonvironmental and palaeoclimatic changes in the time interval after the Weissert event. Fossil assemblages and lithofacies characteristics allowed the reconstruction of the paleoenvironmental history of the section, which is part of a shallow carbonate platform influenced by waves activity, storm events and sea-level changes. The latter induced cyclic emersions of this flat-topped subtropical platform, witnessed by karstification and pedogenesis. Investigations lead to a refinement of the previous biostratigraphy, also producing a close agreement between the biostratigraphic and C-isotope position of the Valanginian–Hauterivian boundary. Numerous green algae and benthic foraminifera bioevents have been identified and six biozones have been defined and anchored to the southern Tethys biozonal schemes. We used biostratigraphy and previous C-isotope stratigraphy to correlate local to global stratigraphic events and to discuss controlling factors influenced this carbonate platform system. An eustatic control on the hierarchical organization of the superbundles, also interpreted in terms of depositional sequences, is evidenced. Most Trangressive/Regressive Facies Trends (T/RFTs) boundaries have been correlated with the “global” Sequence Boundaries and to the Cretaceous eustatic curve. A correspondence between calcareous algae and benthic foraminiferal turnover phases and long-term eustatic events is also shown