Mid-Cretaceous stratigraphy of a cored borehole in the western part of the Central North Sea Basin

Abstract
SUMMARY: A borehole (81/40) drilled in the western part of the Central North Sea Basin cored a sequence of Cretaceous strata ranging from Barremian to Turonian in age. This succession of calcareous mudstones and chalks has been divided into six lithostratigraphical units, two of which include a number of thin volcanic tuff bands (bentonites) of Late Aptian to Early Albian age. The lithologies of each of these units are described, together with a preliminary biostratigraphy for the sequence based upon their diverse foraminiferal and ostracod assemblages. Range charts for the foraminifera and ostracods are presented and the regional significance of the sequence is discussed.