The Global Stratotype Section and Point (GSSP) for the base of the Chattian Stage (Paleogene System, Oligocene Series) at Monte Cagnero, Italy

The GSSP for the base of the Chattian Stage (Paleogene System, Oligocene Series) is defined at meter level 197 in the Monte Cagnero section, which belongs to the pelagic succession of the Umbria-Marche basin (Urbania, central Italy: 43°38?47.81?N-12°28?03.83?E). This level with an astronomical age of 27.82 Ma coincides with the highest common occurrence of the planktonic foraminifer Chiloguembelina cubensis at the base of planktonic foraminiferal O5 Zone and falls in the upper part of calcareous nannofossil NP24 Zone, in the lower part of dinocyst Dbi Zone, and in the lower Chron 9n. The proposal was approved by the International Subcommission of Paleogene Stratigraphy in July 2015, approved by the International Commission of Stratigraphy in August 2016, and ratified by the International Union Geological Sciences in September 2016.