Since the main publication “Integrated stratigraphy of the Oligocene pelagic sequence in the Umbria-Marche basin (Northeastern Apennines, Italy): A potential GSSP for the Rupelian/Chattian boundary” published by Coccioni and others in April 2008, the candidate section at Monte Cagnero (central Italy) has been re-visited. Calcareous plankton biostratigraphy has been implemented with the high resolution dinocyst biostratigraphy accurately calibrated to magnetostratigraaphy and, in addition, some critical calcareous plankton bioevents will be controlled across some key-intervals. A synthesis of all data available on the candidate Chattian GSSP at Monte Cagnero has been presented at STRATI 2013 by Coccioni et al., where it was well accepted by the audience. The proposal, in advanced progress by the leaders of the WG Coccioni and Montanari and including the astrochronological calibration of the Monte Cagnero section based on orbital tuning of high-resolution magnetic susceptibility and calcium carbonate data series, has been submitted officially to the Paleogene Subcommission in June 2015.

Finally, the International Commission of Stratigraphy (ICS) approved the proposal, ratified in September 2016 by the International Union of Geological Sciences (IUGS) at Cape Town, during the International Geological Congress (IGC35). The official ceremony was celebrated on 13 May, 2017, in Urbania.

The GSSP for the base of the Chattian Stage (Paleogene System, Oligocene Series) is now 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.

Meter level 197 falls thirty cm below the base of a prominent, 40 cm–thick limestone bed in the middle of a recessive, 7 m–thick marly interval. This distinctive lithostratigraphic package is easily recognizable in the MCA section, and useful for recognizing the other lithostratigraphic intervals in this section, as well as in other coeval sections for regional correlation.

The description and the data of the GSSP Monte Cagnero section are the subject of a paper accepted for publication in Episodes (Coccioni et al., 2017).

 

 

References

Coccioni R., Marsili A., Montanari A., and Others (2008). Integrated stratigraphy of the Oligocene pelagic sequence in the Umbria-Marche basin (northeastern Apennines, Italy): A potential Global Stratotype Section and Point (GSSP) for the Rupelian/Chattian boundary. GSA Bulletin 120, 487–551.

Coccioni R., Montanari A., Bellanca A., Bice D.M., Brinkhuis H., Church N., Deino A., Frontalini F., Lirer F., Macalady A., Maiorano P., McDaniel A., Marsili A., Monechi S., Neri R., Nini C., Nocchi M., Pross J., Rochette P., Sagnotti L., Sideri M., Sprovieri M., Tateo F., Touchard Y., Van Simaeys S. & Williams G.L. (2013). Integrated stratigraphy of the Monte Cagnero pelagic sequence in the Umbria-Marche basin (northeastern Apennines, Italy): A potential candidate for defining the Global Stratotype Section and Point (GSSP) for the Rupelian/Chattian boundary. STRATI 2013, Lisbon, July 1-7, 2013, Ciencias da Terra, Numero Especial VII, p. 15.

Coccioni, R., Montanari, A., Bice, D.M., Brinkhuis, H.,  Deino, A., Frontalini, F., Lirer, F.,  Maiorano, P., Monechi, S., Pross, J., Rochette, P., Sagnotti, L., Sideri, M., Sprovieri, M.,Tateo, F., Touchard, Y., Van Simaeys, S., and Williams, G.L., 2017, The Global Stratotype Section and Point (GSSP) for the base of the Chattian Stage (Paleogene System, Oligocene Series) at Monte Cagnero, Italy. Episodes (accepted for publication).