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This study summarizes the final results of magnetostratigraphic and biostratigraphic investigations of the Tithonian/Berriasian (J/K) boundary limestones at the locality of Puerto Escano, Spain. The aim is to prepare the background for correlation of an upper Tithonian and lower Berriasian biostratigraphic zonation with global magnetoevents (manifested in detailed magnetostratigraphic profiles) between the Tethyan and the Boreal realms. Magnetostratigraphic studies were applied to an 8.1-m-thick part of the section embracing upper Tithonian and lower Berriasian strata. The average sampling interval was 30 mm. The analysis of the IRM acquisition curves proved the presence of magnetite and hematite, the former mineral being the main carrier of the remanent magnetization. Progressive thermal demagnetization mostly revealed three NRM components, and magnetostratigraphy was based on the directions of the most stable of them, with unblocking temperature varying mostly from 300 to 540 °C. Due to almost parallel beds, the fold test applied to this component did not give convincing results. In contrast, the reversal test received the best classification ‘A’. The detected polarity zones could has been unequivocally identified against the M-sequence of polarity intervals drawn from the Geomagnetic Polarity Time Scale 2004. This fact, together with the results of the reversal test, confirmed the ChRM to be the primary component. The sampled part of the section included a part of magnetozone M20r, full magnetozones M20n to M18r and a part of magnetozone M18n. Especially the detection of two reverse respectively by M20n.1r and M19n.1r with thicknesses only 40 and 90 mm, respectively, required much effort when sampling the section. The calculated sedimentation rate varied from 1 to 5 mm/ky. The positions of the individual events of tintinnoid biostratigraphy (mainly calpionellids) relative to the global magnetic polarity timescale are precisely defined. The base of the Calpionella Standard Zone, which is considered to be a potential J/K boundary indicator in ammonite-free sections from the Tethyan realm, or in sections where calpionellid stratigraphy applies, lies within magnetozone M19n at the level of 35% of its local thickness. None of the boundaries in the calpionellid zonation coincides precisely with any of those in the palaeomagnetic zonation, but the first appearance datum (FAD) of Calpionella grandalpina Nagy, indicating the base of the Intermedia Subzone, lies in close proximity to the base of magnetozone M19r. The last appearance datum (LAD) for Praetintinnopsella andrusovi Borza in Bed 14A corresponds approximately to the base of the Kysuca Subzone.

An analysis of the stratigraphic distribution of ammonite faunas collected from several sections in the Essaouira-Agadir area (western High Atlas, Morocco) has enabled the establishment of a detailed succession of assemblages for the uppermost Hauterivian to lower Upper Barremian interval. All Mediterranean standard zones of this interval have been identified. The correlation potential of bioevents which define and characterise these units is discussed. Two significant regional hiatuses, one at the Hauterivian/Barremian boundary, the other involving the lower part of the Kotetishvilia nicklesi Zone, are related to third-order sea level falls. Moreover, the upper part of the succession corresponding to the upper Toxancyloceras vandenheckii Zone and the entire Heinzia sartousiana Zone is markedly condensed. The taxonomic composition of the ammonite assemblage reveals a strong Mediterranean character, yet, it shows some peculiar features as well.

A detailed analysis of the stratigraphic distribution of ammonites from fourteen sections in the External Zones of the Betic Cordillera has enabled us to identify accurately the sequence of bioevents that take place throughout the uppermost Hauterivian and to propose a more precise biostratigraphic scheme for this interval. Thus, we have divided the two currently admitted zones (the Crioceratites balearis Zone and the Pseudothurmannia angulicostata auct. Zone) into several subzones. Four subzones can be recognised within the Cr. balearis Zone. The base of each subzone is defined by the first occurrence of one of four successive species belonging to the same Crioceratites lineage. These species are: Cr. balearis, Cr. binelli, Cr. krenkeli and Cr. angulicostatus . The Ps. ohmi Zone (which replaces the classical Ps. angulicostata Zone) can be divided into three subzones characterised by three successive species of the genus Pseudothurmannia: Ps. ohmi, Ps mortilleti (here considered as a senior synonym of Ps. catulloi ) and Ps. picteti . According to the current definition, the first occurrence of Taveraidiscus hugii (OOSTER) marks the lower boundary of the Barremian stage. This event fits into a major faunal-renewal episode that begins in the upper part of the Ps. picteti Subzone.

The study of ammonite assemblages collected from the Calcaire inferieur and the Argiles brunes in the region of Safi (Morocco) has allowed us to pinpoint the age of these formations and to attribute them, respectively, to the Boissieri Zone ower part of the Campylotoxus Zone and to the upper part of the Campylotoxus Zone pper Valanginian. These units are also reinterpreted in terms of sequence stratigraphy. In addition, the analysis of the faunal spectrum shows that, although differing in some respects, these ammonite associations are similar to those of other peri-Tethyan platforms, while differing considerably from the basin assemblages.

We discuss the significance of Mediterranean faunas in the study of the traditional Jurassic-Cretaceous boundary based on ammonites. Reviewing the record of ammonites and calpionellids from southern Spain and also discussing data from SE France, Bulgaria, Czechoslovakia, Cuba, Mexico and Argentina, which permit correlation with the Spanish faunas, we conclude that: a) Berriasella jacobi Mazenot is a good index fossil for the base of the Berriasian (=base of the Cretaceous System), b) the jacobi ammonite association clearly differentiates the latest Tithonian (Durangites Zone), c) the genus Kossmatia occurs in shelf deposits and, when present, is very rare in the European Tethys, d) the Mexican Gulf was not the centre of dispersal for Durangites or Kossmatia .

In the present paper we discuss the possibilities for the correlation of ammonites, calpionellids and calcareousnannofossils as recorded in the Puerto Escano section in Southern Spain (province of Cordoba), where a very detailed sampling was carried out. The section has proved to be a very significant one due both to the favorable outcrop and bedding preservation, and to the abundance of well-preserved fossil remains. We consider the selected section at Puerto Escano to be one of the most advantageous sites for the analysis of the stratigraphic distribution of significant macro and microfossils and thus for the study of the traditional Jurassic-Cretaceous boundary in ammonitico-rosso facies of the Mediterranean area.