The belemnite zonation of the uppermost Cretaceous in the Maastricht-Aachen-Liège, Brabant-Méhaigne and Mons areas (Belgium, southeast Netherlands) (original) (raw)

2011, Geologie En Mijnbouw

During the last decades, belemnitellid cephalopods (Coleoidea) have been considered to be of fundamental importance for biostratigraphy and correlation of the Upper Cretaceous of Europe, particularly during the Santonian to Maastrichtian stages, because they are common and widely distributed and have a high fossilisation potential (Christensen, 1996, 1997). However, detailed studies carried out by Christensen (1995, 1999, 2000a, b) have shown a significant regional component within distributional patterns, in particular for the genus Belemnitella, during the late Campanian in northwest Europe. While in Norfolk (southeast England), the Maastricht-Aachen-Liège area (MAL; southeast Netherlands and adjacent areas) and the Mons Basin (southern Belgium), members of the lineage Blt. mucronata / woodi / minor I/ minor II predominate, Blt. mucronata persisted in northern Germany (Misburg-Höver area, east of Hannover) and Skåne, southern Sweden, (almost) to the top of the Blt. woodi Zone in the lower upper Campanian. In the upper upper Campanian, members of the Blt. minor group have not (yet) been identified in northern Germany (Kronsmoor, Lägerdorf), but there Blt. langei (sensu Schulz, 1978) and Blt. schulzi appear, two forms apparently restricted to that region and unknown from Norfolk, the Mons Basin and the MAL area. From the Vistula (Wisła) River valley in east-central Poland, another rich Belemnitella fauna has recently been noted in the upper Campanian, comprising additional regional elements such as Blt. posterior Kongiel, 1962 (Christensen, unpubl. data; Remin, 2007). According to Christensen (2000b), his earlier suggestion (see Christensen, 1999) that the upper Campanian belemnite zonation of Norfolk could be used as a formal zonation throughout northwest Europe was no longer tenable. Hence, it is necessary first to establish regional belemnite zonations based on developmental lineages of the locally dominant species and, secondly, to note temporary invasions of additional species. These short-term invasions may be of great stratigraphic value as has been documented for instance for Bln. praearkhangelskii in the upper lower Maastrichtian of northwest Europe (Schulz, 1979; Keutgen, 1997). Alternatively, such temporary immigration events may reflect temporarily suitable environmental