Revised Upper Cenozoic stratigraphy of the Dutch sector of the North Sea Basin: towards an integrated lithostratigraphic, seismostratigraphic and allostratigraphic approach

Abstract

A revised Upper Cenozoic stratigraphic framework of the Dutch sector of the North Sea Basin is presented whereby offshore stratigraphic units are integrated or correlated with onshore units. The framework is based on an integrated stratigraphic approach that combines elements of lithostratigraphy, seismostratigraphy and allostratigraphy. Offshore formations are redefined in terms of seismofacies and lithofacies associations, and are differentiated on the basis of common genesis and stratigraphic position. These facies associations represent five major depositional environments, which occur in repetitive successions in the subsurface of the Netherlands: Marine, Coastal, Glacial, Fluvial, and Local Terrestrial. Five conceptual basin-wide bounding discontinuities are identified in the North Sea-Basin that span land and sea. They are represented by both seismostratigraphic and lithostratigraphic unconformities and interpreted as surfaces that formed as a result of North Sea Basin-wide changes in depositional systems. Their formation relates to sea level rise, continental-scale glaciations, and tectonic processes. The bounding discontinuities separate informal allostratigraphic groups of formations that have a grossly uniform geologic setting in common. While the allostratigraphic principles provide a view on the stratigraphy on the largest spatial and temporal scale, the genetic concept facilitates mapping on a local scale.