Cenozoic Foraminiferal and Dinoflagellate Cyst Biostratigraphy of the Central North Sea

Abstract

We present a detailed Cenozoic biostratigraphy for Paleogene bathyal and Neogene ncritic strata, north of 55° in the central North Sea, and offshore mid-Norway, using both forarninifera and dinoflagellate cysts. Construction of the zonations was assisted by the quantitative stratigraphic methods RASC and STRATCOR. Eight Paleogene and four Neogene interval zones of benthic and some planktonic foraminifera are defined. These zones involve the average last occurrence of 64 taxa present in a minimum of 7 of 33 wells studied. Eighteen geographically rare, but stratigraphically important foraminifers and dinoflagellate cysts were inserted as unique events. Thirteen Paleogene dinoflagellate cyst interval and peak zones are defined that are interrelated with the foraminiferal zonation. The Paleocene-Eocene boundary is assigned at the top of dinoflagellate cyst zone T2c (Apectodinium aligusturn LO), immediately above the upper limit of the keticulophragmium paupera Zone. The Coscinodiscus Zone and dinoflagellate cyst zone T3A (acme of Deflandea oebisfeldensis) are earliest Eocene in age. Uppermost Eocene strata may be largely missing in the central North Sea, as is part or all of the Upper Miocene.