Figure 3. Upper Cretaceous isopach map of the North Sea (redrawn from Ziegler, 1990). The Late Cretaceous dome is illustrated by the thick deposits both in the central rift system and in the marginal troughs of the Norwegian-Danish Basin (NDB), along the Tornquist Zone (TZ) in the eastern North Sea, and in the Sole Pit (SP) area in southwestern North Sea. The rift shoulders along the southwest margin of the Central Graben (CG) are intact, while the apex of the dome to the east of the Central Graben has migrated towards the northeast. The Late Cretaceous dome has thus developed into an asymmetric structure. EB: Egersund Basin; VG: Viking Graben; MFG: Moray Firth Graben.