The Inception and Evolution of the Late Cretaceous Rudist Bearing Carbonate Platforms in the Mediterranean Tethys: Mirror of Geodynamically Induced Biosphere-Geosphere Interactions.

Middle Cretaceous (Aptian-Turonian) time was a period of unusually intense geodynamic activity that lead to major paleogeographic/paleoceanographic changes. These are coincident with relevant geological events as turnovers of biotic communities, oceanic anoxic events (OAEs), thermal maximum and disruptions of geochemical cycles in seawater. The Late Cretaceous evolution of rudist-rich carbonate platforms of central Mediterranean Tethys is investigated here to derive possible genetic links between geodynamically induced environmental changes and the observed stratigraphic record. Stratigraphic and palaeoecologic data are coupled to available geochemical proxies to fulfil a detailed integrated approach to event and genetic stratigraphy. Several major paleoceanographic events falling in the latest Albian, C-T boundary, middle-late Turonian boundary, Coniacian-Santonian boundary and middle Campanian have been individuated. Our results suggest that rudist-rich carbonate platforms have coherently reflected the fluctuating environmental conditions of the oceanic realm mostly induced by changing temperature, Mg/Ca ratio and pCO2. These platforms are the result of biosphere-geosphere interactions which were induced by large-scale, long-term geodynamic forcings.