Palaeocene-Oligocene tectonics of NW Europe

Summary During the Palaeogene in NW Europe, a Gallic subplate was very nearly created. This plate was almost entirely bordered by plate boundaries, although not of equivalent ages. To the N, the N Atlantic began to open about 56 Ma ago, the Alpine convergent boundary extended southwestwards to the Pyrenean subduction zone; on the NE side a N British Palaeocene/early Eocene fracture-dyke boundary appears to pass southeastwards across the North Sea into a Lutetian to Burdigalian rift system. There is an age disparity between the fracturing and NW dyke intrusion in Britain and the fracturing and formation of the Rhine Graben. The last dykes in Britain (Ypresian) were intruded not long before the important subsidence of the Rhine Graben (earliest Lutetian), but their causes were different. The British dyke fractures propagated southeastwards via the Cleveland Dyke towards the North Sea, whereas the Rhine Graben propagated northwards towards the Zuider Zee depression. However, the structures from both sides converged in the Sole Pit Basin in the North Sea with the result that a continuous though not coevally-originated fracture system developed from NW Scotland to the Alps.