Danian dinoflagellate zonation, the C-T boundary and the stratigraphical position of the fish clay in southern Scandinavia

Abstract. Two Swedish borehole cores covering the Danian, and three Danish outcrop sections covering the Lower Danian, were analysed for dinoflagellates.

This study suggests that the Swedish sections, in contrast to previous investigations, are the most complete sections across the Cretaceous-Tertiary boundary in the Danish Embayment. As a consequence, the previously established biozonation can be modified to include one more basal Danian zonule.

A detailed study of the dinoflagellates of the Fish Clay in Denmark suggests that this layer was formed in a low salinity environment in eastern Denmark and in a stable marine environment in western Denmark. In addition, the Fish Clay is shown to be biostratigraphically older in eastern Denmark than in western Denmark.