COMPARED SEQUENCE STRATIGRAPHY AND GRADE- DATING BY PLANKTONIC-FORAMINIFERA OF THE CAMPANIAN-MAASTRICHTIAN AND PALEOCENE SERIES FROM SOME SECTIONS OF SOUTHWESTERN EUROPE AND NORTH-AFRICA

From the analysis of the open marine beds enclosing the WT boundary al ong several cross-sections of SW Europe and North Africa, a subdivisio n is proposed into nine Campanian-Maastrichtian depositional sequences followed by five Palaeocene sequences. These sequences have been corr elated from one section to another by means of planktonic Foraminifera classic biozones and supported in the Cretaceous by numeric ages comi ng from the grade-dating method applied to Globotruncanids. In the lat ter case, sequences belong to two different types separated by the pre sence or the absence of lowstand chaotic deposits such as breccias and olistostromes. The dark clays of the WT boundary containing the Iridi um anomaly can be regarded as a 3(d) order sequence boundary. They als o correspond to the base of a 2(d). Order cycle which is locally (Beam ) underlined by a gap of the Early Palaeocene the underlying Maastrich tian marls, everywhere grade-dated around 65.2-65.3 Ma, never being si gnificantly eroded.