Did the European dinosaurs disappear before the K-T event? Magnetostratigraphic evidence

Abstract

Debate on the non-catastrophic or catastrophic extinction of the dinosaurs by an asteroid impact, K-T event, remains a controversy and is mainly based on the interpretation of the sedimentary continental sequences in the North American Western Interior. The global aspect of this event needs to be tested in sedimentary record from all continents where continuous terrestrial deposits through the Cretaceous-Paleogene are well preserved. In the western Mediterranean realm, recognition of the Cretaceous-Paleogene boundary is limited by the lack of biostratigraphic data in the upper Cretaceous-lower Tertiary continental sedimentary sequences. New magnetostratigraphic results were obtained from the analysis of two sections in southern France and compared to previous results in northern Spain. The last occurrence of in situ dinosaurs eggshells, the only dinosaur remains found, is located in Chron 30n (southeast France) or 31n (southwest France and northern Spain). This last occurrence could demonstrate that the extinction of the European dinosaurs occurred prior to the Cretaceous-Paleogene boundary, and would therefore support the idea of a gradual or stepwise extinction unlinked to the K-T event.