Connecting the Chalk Group of the Campine Basin to the dinoflagellate cyst biostratigraphy of the Campanian to Danian in borehole Meer (northern Belgium)

Abstract

A palynological study of the Chalk Group (Campanian-Danian) in the Meer borehole (northern Belgium), which penetrated the thickest succession known in the Campine Basin, has revealed diverse, well-preserved organic-walled dinoflagellate cyst assemblages. The succession contains numerous chronostratigraphically significant dinocyst events, which are based mainly on the highest consistent occurrences of index species. At least 35 bioevents have enabled a subdivision into nine intervals, at stage or substage level within the Campanian to Danian interval as based on comparison with coeval assemblages elsewhere in northwest Europe, inclusive of stratotypes of stages and stage boundaries. Bio-events allow correlation of the section studied with the Campanian Exochosphaeridiuml masureae, Areoligera coronata and Samlandia mayi zones, the Maastrichtian Pervosphaeridium tubuloaculeatum, Deflandrea galeata and Hystrichostrogylon coninckii zones, and the Danian Damassadinium califomicwn Zone. In addition, a correlation with other zonal schemes for the southern North Sea Basin and with conventional northwest European belemnite zones is presented. Comparisons with Boreal and Tethyan realms confirm that most bio-events may also be useful for interregional and global correlation. The Campanian-Danian dinocyst biostratigraphy of the Meer borehole is put alongside geophysical well logs and an ecozonation, in order to check the validity of lithostratigraphical correlations across the Campine Basin. This first, detailed correlation attempt shows that sensitivities to facies change associated with differences in accommodation space and sediment supply appear to be at the base of slight, yet consistent, shifts between the local lithological succession and the standard lithostratigraphical scheme of the Maastricht type area.