Planktonic foraminifers across the Bonarelli Event (OAE2, latest Cenomanian): The Italian record

A high-resolution, quantitative study of the planktonic foraminiferal assemblages across the Bonarelli Level (OAE2, latest Cenomanian) of Italy from different areas and geological settings, has allowed the recognition of several events and biotic changes, including acmes and crises of different genera. It provides evidence of a progressive and rapid change of palaeoenvironmental conditions, reaching a climax coincident with the Bonarelli Event, and of the subsequent, gradual, although not complete, resumption of previous conditions. The observed pattern is illustrated by marked changes in the assemblages that indicate five discrete phases of environmental perturbation within the marine ecosystem. Though there are several similarities, our analyses highlight that each section has its own peculiarities, clearly indicating more or less extreme environmental conditions.