Lithostratigraphy of the Neogene succession of the Danish North Sea

The Neogene of the Danish North Sea is more than 1200 m thick. Despite being penetrated by numerous wells, formal lithostratigraphic subdivision of this succession has previously been restricted to the lowermost part. This monograph presents a comprehensive lithostratigraphy of the offshore Neogene of Denmark, in part extending recognised onshore units into the offshore realm. The mainly Lower Miocene deltaic deposits are referred to the Ribe Group, which is subdivided into six formations: the Klintinghoved, Bastrup, Arnum, Odderup, Dany (new) and Nora (new) Formations. The lowermost Miocene Vejle Fjord and Billund Formations known from the onshore lithostratigraphy are absent in the offshore wells. The dominantly fully marine Middle and Upper Miocene sediments are referred to the Måde Group, subdivided into the Hodde, Ørnhøj, Gram, Marbæk and Luna (new) Formations; the Luna Formation includes the Lille John Member (new). The Pliocene deltaic deposits are referred to the Eridanos Group(new), which is subdivided into the Vagn (new), Emma (new) and Elin (new) Formations. The depositional history of the Neogene of the Danish North Sea sector is presented based on a detailed reconstruction of subsurface morphology by the mapping of stratigraphical surfaces dated by biostratigraphy. During the Early Miocene, deposition in the Danish North Sea was dominated by progradation from Scandinavia; large deltas built out into the Danish onshore area from the north and north-east. West of the main deltas, muddy contourites periodically accumulated on the slope, accentuating shelf progradation. The Middle and Late Miocene period was mostly characterised by fully marine conditions and deposition of mud. By the end of the Miocene, progradation of delta systems from Scandinavia into the North Sea resumed, and the shoreline reached the westernmost part of the Danish North Sea sector. During the Pliocene, new source areas in central and eastern Europe, such as the Carpathian Mountains, were activated and a huge delta system, the so-called Eridanos Delta, began to fill the North Sea Basin from the east and the south-east. Due to increased subsidence of the basin associated with the loading of sediments of the Eridanos Delta, the northern systems were flooded. Although the Danish North Sea thus mainly received sediments from central Europe during the Pliocene, progradation from Scandinavia resumed at the end of the Pliocene.