Stratigraphic and geophysical maps of the northern and southern North Sea basin are used to study mechanisms of intracratonic basin formation. These maps include (1) tectonic subsidence for ten stratigraphic units, (2) predicted and observed sediment overpressure, (3) geographic variation of compaction constants, (4) net basement fault extension, (5) free-air gravity, (6) flexural rigidity, (7) heat flow, and (8) predicted hydrocarbon maturation.

In northern areas of the North Sea, observed basement-fault extension, crustal thinning, present-day flexural rigidity, and tectonic subsidence are predicted reasonably well by a simple stretching model of basin formation with rifting phases during the Triassic and mid-Jurassic/Early Cretaceous. In southern areas of the North Sea, however, a similar analysis suggests that other non-extensional rift-related processes dominated basin evolution. The effects of anomalously active aesthenospheric convection, coupled with basalt-eclogite and deep-crustal dewatering reactions, are considered as possible additional mechanisms.

The troughlike form of Quaternary tectonic subsidence suggests a new phase of rifting may be starting in the North Sea. The importance of such thermal rejuvenation is borne out by the association of areas of differential subsidence with high heat flow and low flexural rigidity. One component of tectonic reactivation during this period may be due to thermally induced isostatic reequilibration of older tectonic loads.