The Berriasian/Valanginian boundary in the Mediterranean region: new data from the Caravaca and Cehegin sections, SE Spain

Biostratigraphic data provided by the sections of the Caravaca-Cehegin regi on, SE Spain, have contributed decisively to the lively debate that has tak en place in recent years concerning the Berriasian/Valanginian boundary. Th is work presents the results from new integrated stratigraphic analyses of these sections, based on the distribution of ammonites, calpionellids and c alcareous nannofossils, and their calibration with the magnetic polarity sc ale. It is confirmed that the conflicting interpretations in the literature on the distribution of some ammonites and calcareous nannofossil species a re mainly due to differences in taxonomic assignment. The event succession observed allows precise characterization of the Berriasian/ Valanginian bou ndary, defined by the first occurrence of Calpionellites darderi. Some of t he sections studied fulfil the prerequisites to be considered as potential boundary stratotypes. (C) 2000 Academic Press.