NORTH-SEA RIFT SYSTEM

The Mesozoic North Sea rift forms an integral part of the Arctic-North Atlantic rift system. Rifting activity in the North Sea commenced during the earliest Triassic. During the mid-Jurassic the central North Sea underwent a temporary doming stage. Crustal extension peaked during the Late Jurassic-earliest Cretaceous, abated subsequently and terminated altogether during the Paleocene. The saucer-shaped Cenozoic post-rift basin straddles the axis of the Viking and Central grabens. This speaks for the applicability of a depth dependent pure shear model rather than a simple shear model. Geophysical data indicate an important discrepancy between upper and lower crustal attenuation across the North Sea rift, suggesting that during rifting processes the Moho-discontinuity was seriously destabilized. This requires a basic modification of currently favoured crustal stretching models.