Victoriano Pujalte (a), Xabier Orue-Etxebarria (a), Estibaliz Apellaniz (a), Fernando Caballero (a), Simonetta Monechi (b), Silvia Ortiz (c) & Birger Schmitz (d)
(a) Department of Stratigraphy and Paleontology, Faculty of Science and Technology, University of the Basque Country UPV/EHU, Ap. 644, 48080 Bilbao, Spain. E-mail: victoriano.pujalte@ehu.es
(b) Dipartimento di Scienze della Terra, Università di Firenze, Via La Pira 4, I-50121 Firenze, Italy.
(c) PetroStrat Ltd, Tan-y-Graig, Parc Caer Seion, Conwy LL32 8FA, Wales, UK.
(d) Division of Nuclear Physics, Department of Physics, University of Lund, P.O. Box 118, SE-221 00 Lund, Sweden.