Geological indications for Palaeogene uplift in the eastern North Sea Basin

The timing and effect of the Cenozoic uplift of Scandinavia has been investigated using a multi-disciplinary approach involving sedimentological, seismic and biostratigraphic data from the Danish and the adjacent Norwegian parts of the North Sea Basin. It is concluded that significant uplift took place periodically throughout the Palaeogene possibly marking an earlier onset of the so-called "Neogene uplift" of Scandinavia. This conclusion is based on a number of sedimentological observations, including smectite content, grain-size variations, kaolinite thermal stabilities and T_max values supported by seismic reflection geometries and biostratigraphic data. These data indicate several phases of re-working of Palaeogene and older sediments situated further to the east and northeast during the middle to late Eocene and during the middle to late Oligocene. The tectonic patterns were similar during the late Paleocene and the Oligocene with some inversion taking place, whereas no inversion has been observed during the Eocene. Main provenance areas were to the north and northeast during the Paleocene and Oligocene, whereas the Eocene sediments originate mainly from the British Isles to the west. It is proposed that Palaeogene uplift of Scandinavia was associated with regional tectonic movements along crustal zones of weakness, which were reactivated as they accommodated strain induced by the Alpine Orogeny and the opening of the North Atlantic.