In the Netherlands offshore sector, available data and knowledge of the sediments of the Upper Cretaceous to Lower Tertiary (Danian) Chalk Group is limited due to its hitherto restricted significance as a hydrocarbon reservoir. For example, the stratigraphic subdivision of the Chalk in this area comprises only three formations, i.e. the Cenomanian Texel Formation (CKTX), the Turonian to Maastrichtian Ommelanden Formation (CKGR) and the Danian Ekofisk Formation (CKEK), contrary to more detailed subdivisions used in sectors where the Chalk does form an important hydrocarbon-producing interval. The first aim of this thesis is, therefore, to present a more detailed subdivision of the Chalk Group in the Dutch North Sea sector. Due to the scarcity of cored intervals and biostratigraphical data, this subdivision is largely based on the interpretation of geophysical data. The chalks of the North Sea area show a great variety of lithofacies resulting from a broad spectrum of depositional mechanisms and physical and chemical compaction processes. Chalk was originally formed by settling of calcareous nannoplankton remains from suspension in the water column. However, in areas that underwent significant tectonic activity, slope instability processes resulted in resedimentation of the autochthonous chalk. Investigation of these sedimentary processes, as well as their controls and products, not only yields additional information on the sedimentology and diagenesis of the Chalk Group, but also on the paleoenvironmental and basinal evolution of the study area during the Late Cretaceous and early Paleocene. Therefore, the second aim of this thesis is to reconstruct the sedimentary development of the Chalk Group in the Dutch sector of the North Sea. Although the Chalk Group is characterised by a remarkably uniform lithology, marked lateral variations in acoustic velocity are present throughout the North Sea basin. These acoustic velocity variations are primarily the result of variations in compaction, which in turn are caused by ...