The neglected history of Oceanic Anoxic Event 1b: insights and new data from the Poggio le Guaine section (Umbria-Marche Basin)

The upper Aptian to lower Albian interval (similar to 114-109 Ma) represents a crucial period during Earth's history, with a major evolution in the nature of mid-Cretaceous tectonics, sea level, climate, and marine plankton communities. Interestingly, it also includes multiple prominent black shale horizons that are the sedimentary expression of oceanic anoxic event (OAE) 1b. However, due to a set of geological, stratigraphic, and taxonomic challenges, difficulties constraining this OAE may sometimes result in inaccurate correlation.