After many years searching for a suitable section to define the Ypresian/Lutetian boundary Stratotype, the Gorrondatxe section was found and the Lutetian GSSP was defined in a very expanded and continuous section. The Ypresian/Lutetian Working Group decided, during the final Workshop in Getxo (near Bilbao, Spain) in September 26, 2009, to define the Lutetian GSSP at meter 167.85 of the Gorrondatxe section in a dark marly level where the nannofossil Blackites inflatus first appears, approximately 48 Ma ago. Two candidate sections Agost and Gorrondatxe where proposed and the Lutetian GSSP at Gorrondatxe was elected by consensus after long discussions. All the events near the base of the Lutetian Stage were discussed and it was considered that the absence of B. inflatus is not so certain and relevant like the presence of B. inflatus in the lower sample of the Lutetian Stage Stratotype found by Aubry (1986) in Palaeo.Palaeo.Palaeo. The FO of Discoaster sublodoensis was considered too old because it appears in Chron 22n, which is clearly Ypresian. Consequently, it was considered that the FO of B. inflatus is the best marker because it appears at or just below the base of the Lutetian Stage Stratotype of Paris. Furthermore, in the lower Lutetian of Paris there is Nummulites laevigatus and in Gorrondatxe the first sample above, with larger foraminifera, contains the first Nummulites laevigatus like in the Paris bassin. Planktic foraminifera were not used because of their absence in the Lutetian Stage Stratotype in Paris. Nevertheless, it is clear that the first appearance of Hantkenina in all the sections studied is about 4 Ma younger than the FO of B. inflatus. The report to be voted by ISPS, ICS and IUGS is being prepared. The following papers co-authored by the members of the Y/L Working Group were published:

Larrasoaña, J.C., Gonzalvo, C., Molina, E., Monechi, S., Ortiz, S., Tori, F. & Tosquella, J. (2008). Integrated magnetobiochronology of the Early/Middle Eocene transition at Agost (Spain): implications for defining the Ypresian/Lutetian boundary stratotype. Lethaia. 41, 395-415.

Ortiz, S., Gonzalvo, C., Molina, E., Rodríguez-Tovar, F.J., Uchman, A., Vandemberghe, N., & Zeelmaekers, E. (2008). Palaeoenvironmental turnover across the Ypresian-Lutetian transition at the Agost section, southeastern Spain: in search of a marker event to define the Stratotype for the base of the Lutetian Stage. Marine Micropaleontology. 69, 297-313.

Payros, A., Orue-Etxebarria, X., Bernaola, G., Apellaniz, E., Dinarès-Turell, J., Tosquella, J., & Caballero, F., (2008). Characterization and astronomically calibrated age of the first occurrence of Turborotalia frontosa in the Gorrondatxe section, a prospective Lutetian GSSP: implications for the Eocene time scale. Lethaia. 42, 255-264.

Payros, A., Tosquella, J., Bernaola, G., Dinarès-Turell, J., Orue-Etxebarria, X. & Pujalte, V. (2009). Filling the North European Early/Middle Eocene (Ypresian/Lutetian) boundary gap: Insights from the Pyrenean continental to deep-marine record. Palaeogeography, Palaeoclimatology, Palaeoecology. 280, 313-332.

Report by Eustoquio Molina, Chairman