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
C9n. 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
of Geological Sciences in September 2016.