Dinocyst stratigraphy and palaeoenvironmental interpretation of the Cretaceous/Paleogene boundary at Stevns Klint, Denmark

There has been some doubt cast upon the results of dinoflagellate cyst studies previously undertaken at Stevns Klint, Denmark, one of the classic outcrops of the Cretaceous–Palaeogene (K–Pg) boundary. A re-examination of both the uppermost Maastrichtian chalks and an expanded section of the Fish Clay (Fiskeler Member) has identified some differences between our findings and the earlier work. The white coccolith chalk of the uppermost Maastrichtian (Sigerslev Member) is placed in the Palynodinium grallator Zone. The last occurrence of P. grallator lies within the Hojerup Member, which represents a shallower-water marine succession that is characterized by a series of dune-like structures. This confirms a latest Maastrichtian age for the P. grallator Zone. Within the Fiskeler Member, a number of new taxa appear, including Carpatella cornuta, Xenicodinium reticulatum, and Fibrocysta spp. The highest samples in the Fiskeler Member indicate a progressive transition towards more proximal environments, with no dinoflagellate cysts recorded, having been replaced in the samples by pollen grains.