Building an integrated stratigraphy for the upper Santonian – lower Maastrichtian of NW Europe: carbon-isotope correlation, micropalaeontology and palynology of the Norfolk Chalk, England

The stratigraphic distributions of benthic foraminifera and organic-walled dinoflagellate cysts (dinocysts) from the upper Santonian–basal Maastrichtian of the Trunch boreholes, Norfolk, are presented. Improved biostratigraphic correlation to regional outcrops, including the Campanian–Maastrichtian boundary succession on the Norfolk coast, is provided by 43 key foraminiferal taxa combined with macrofossil records. The chronostratigraphy of the cores is reinterpreted considering the revised correlation. Benthic foraminiferal interval zones UKB.15 Bolivinoides strigillata to UKB.21 Swiecickina paleocenica are represented. Occurrences of 199 dinocyst taxa and their semi-quantitative abundances are recorded. The ranges of 45 taxa are compared to published records from Europe and the circum-Arctic region. A total of 49 dinocyst bioevents comprising the lowest and highest occurrences of taxa provide key markers for correlation and dating of the upper Santonian–lower Maastrichtian. Results are combined with lithostratigraphic, macrofossil, foraminifera, calcareous nannofossil and δ13Ccarb data to calibrate carbon-isotope events (CIEs) that enable improved correlation to sections in southern England, northern Germany, Denmark and SW France, including the Maastrichtian GSSP at Tercis les Bains. New Grimmensis, Obtusa and Sumensis CIEs are defined within the Campanian–Maastrichtian boundary interval. The integrated stratigraphy impacts the placement of stage and substage boundaries in the NW European Chalk and requires a reassessment of current stage allocations to established bioevents. Boundary intervals are associated with prominent CIEs, regional lithological markers, and episodes of enhanced biotic turnover. These are the: Late Santonian (Grobkreide), Mid-Campanian (Trunch Hardgrounds), Late Campanian (Catton Sponge Beds) and Campanian–Maastrichtian Boundary (Trimingham Sponge Beds) Events.