Annual Report 2011 of the Ypresian/Lutetian Boundary Stratotype Working Group

The Global Stratotype Section and Point (GSSP) for the base of the Lutetian Stage (early/middle Eocene boundary) was defined at 167.85 meters in the Gorrondatxe sea-cliff section (NW of Bilbao city, Basque Country, northern Spain; 43º 22’ 46.47’’N, 3º 00’ 51.61’’ W). This dark marly level coincides with the lowest occurrence of the calcareous nannofossil Blackites inflatus (CP12a/b boundary), is in the middle of polarity Chron C21r, and has been interpreted as the maximum-flooding surface of a depositional sequence that may be global in extent. The GSSP age is approximately 800 kyr (39 precession cycles) younger than the beginning of polarity Chron C21r, or ~47.8 Ma in the GTS04 time scale.

The GSSP was approved by the International Commission of Stratigraphy in January 2011, and ratified by the International Union of Geological Sciences in 2011. Finally, the GSSP was officially published in Episodes:

Molina E., Alegret L., Apellaniz E., Bernaola G., Caballero F., Dinarès-Turell J., Hardenbol J., Heilman-Clausen C., Larrasoaña J.C., Luterbacher H., Monechi S., Ortiz S. Orue-Etxebarria X., Payros A., Pujalte V. Rodríguez-Tovar F.J., Tori F., Tosquella J. & Uchman A. (2011). The Global Stratotype Section and Point (GSSP) for the base of the Lutetian Stage at the Gorrondatxe
section, Spain. Episodes. 34(2), 86-108.

Report by Eustoquio Molina, Chairman.