Middle Jurassic to Early Cretaceous Tectonic Movements and Basin Evolution in the Northern North Sea

Abstract

Fault growth, interaction and linkage in an extensional environment determine the geometry of rift basins and the architecture of syn-rift deposition. By integrating subsurface datasets, we aim to address the structural evolution and its impact in basin evolution from Middle Jurassic to Early Cretaceous in the northern North Sea. The Viking Group is subdivided into four genetic sequences (SQ1-SQ4) from Bathonian to Early Berriasian age. Seismic interpretation shows that onset of rifting occurred during SQ1 and created the initial proto-morphology of the Jurassic sedimentary basin. Continued rifting in SQ2 separated the Sogn Graben from the Viking Graben, and presented two rhomboidal sub-basins. Persistent rifting during SQ3 generated major fault complexes, which divided the northern North Sea into four rhomboidal fragments. The arrangement of faulted blocks displayed a sigmoidal configuration. Fault activity decreased during SQ4 and constrained smaller rhomboidal depocenters near the western margin. Tilted fault blocks were exhumed and eroded during SQ4. The rhomboidal depocenters and sigmoidal blocks suggest a shear component while rifting. We propose that regional extension was conducted by oblique rifting with extension oriented near 120o. The narrower width of the Sogn Graben might had been caused by confined extension from the More-Trondelag sinistral strike-slip fault complex.