The structural evolution of the central North Sea has been dominated by subsidence throughout the last 65 m.y., which occurred at different rates in various segments of the basin.

The bulk of the Tertiary sediments accumulated in a relatively narrow, elongate basin in the central North Sea. The base of the Tertiary today is deeper than 3,250 m in the axis of the Central graben. The overall shape of the basin is well defined by contours decreasing in depth northward to the Norwegian Sea, and landward in all other directions.

Different rates of subsidence of the various subbasins are evident by comparison of isopach maps. During the Paleocene and Eocene, the main depocenter was located in the northwest part of the North Sea (the Viking graben), whereas the Oligocene and Miocene depocenters are observed to have been in the southern part of the Central graben. In addition, two ancillary depocenters have been identified for other intervals of the Tertiary: the Moray Firth and the Central Jutland portion of the Danish subbasin.