Intraplate stresses and the stratigraphic evolution of the North Sea Central Graben

Abstract

We present results of stratigraphic modelling and quantitative analysis of subsidence data for the southern part of the North Sea Basin. Tectonic subsidence curves are given for fifteen wells in the northernmost segment of the Dutch North Sea and the southern part of the Dutch Central Graben. These curves have been supplemented with tectonic subsidence curves for eight wells from the Broad Fourteens and West Netherlands Basins. Subsidence analysis and thermo-mechanical modelling show that Late Jurassic and Early Cretaceous multiple stretching phases with a finite duration are required to explain the observed stratigraphic record. Our analysis demonstrates the important role of intraplate stresses in the evolution of these basins. The paleo-stress curve inferred from the stratigraphic modelling shows a trend with a change from tensional and neutral stresses during Mesozoic times to a stress regime of more overall compressional character during Cenozoic times. Superimposed on this long-term trend are short-term stress fluctuations. This paleo-stress curve and the associated stratigraphic record of the Dutch North Sea Basin sheds light on the record of paleo-stress measurements in the Northwestern European platform and is consistent with data on the kinematic evolution of the Tethys belt. These findings demonstrate the key-importance of tectonics and stress-induced vertical motions - related to rifting events in the northern Atlantic region and the interaction of the Eurasian and African plates - in controlling the stratigraphic evolution of the North Sea Basin.