The Base of the Neogene System, Miocene Series and Aquitanian Stage is defined in the Lemme-Carrosio Section (35m from the top of the section) in the village of Carrosio, south of the town of Gavi and north of Voltaggio (Allessandria Province), Italy.
The Lemme-Carrosio Section is located in the village of Carrosio. Longitude: 8°50'11" East; Latitude: 44°39'32" North. Carta Geologica d'Italia: Foglio Genova No. 82 (1:100 000); Tav. Voltaggio I NE (1:25 000).
The area of the Lemme-Carrosio Section is situated within the Piedmont Tertiary Basin, in southern Piedmont, Italy. In the Lemme Section, the Rigoroso Fomation is characterized by poorly to very poorly sorted sediments which can be classified as fine and medium grained silts with fine silts dominating.
An excellent lithological marker for the GSSP is provided by a distinct boundary between lithologic Unit A (the more massive part of the section) and the overlying lithologic Unit B-1 (the more stratified part of the section). At the 50m mark from the top there is a horizon with yellowish nodules. The GSSP is exactly 15m above this lithologic boundary. A layer with yellowish nodules lies in lithologic Subunit B2, exactly one meter below meter 35.
Magnetic -- base of Chron C6Cn.2n; planktonic foraminifer FAD of Paragloborotalia kugleri; calcareous nannofossil near LAD Reticulofenestra bisecta (base Zone NN1); Oxygen isotopic event Mi-1.
The GSSP is potentially correlatable worldwide by means of magnetostratigraphy, marine microfossil biostratigraphy, and/or stable isotope stratigraphy.
Astronomical cycles in sediments
Biostratigraphic correlations allow the interpretation of the geomagnetic pattern of this section using the magnetobiochronologic scale of Berggren et al. (1995). Association of the distinct polarity reversals at meter 35 with biostratigraphic events cited above permit identifications of the magnetozones as Chron C6Cn.2r and Chron C6Cn.2n respectively. This unambiguous reversal pattern and the excellent biostratigraphic markers have been among the main reasons for defining the base of the Neogene at meter 35 of the Lemme-Carrosio section.
Steiniger, F. F., Aubry, M. P., Berggren, W. A., Biolzi, M., Borsetti, A. M., Cartlidge, J. E., Cati, F., Corfield, R., Gelati, R., Iaccarino, S., Napoleone, C., Ottner, F., Roegl, F., Roetzel, R., Spezzaferri, S., Tateo, F., Villa, G., and Zevenboom, D., 1997. The Global Stratotype Section and Point (GSSP) for the Base of the Neogene. Episodes 20/1, p. 23 - 28.