New insights into salt tectonics in the northern Dutch offshore: a framework for hydrocarbon exploration

The northern Dutch offshore is an area that has seen less hydrocarbon exploration activity than other areas of The Netherlands. Acquisition of a new regional 3D seismic dataset allowed further testing and re-evaluation of established geological concepts in this area. It is recognized that the presence and movement of Upper Permian Zechstein evaporites had a major impact on depositional patterns in Mesozoic sediments, structural development and hydrocarbon migration. As such, this study looks specifically at the role of salt tectonics in tectonosedimentary development. To assess this salt tectonic evolution within its structural context, a restoration of the Step Graben and Dutch Central Graben was performed. It follows that depositional patterns are closely linked to the nature of salt structure movement and the timing of regional tectonism. For example, during Late Triassic rifting, salt pillows developed and sedimentation focused away from salt structures into depocentres along regional fault trends. Restoration results show that this interplay between salt movement and tectonism is needed to accommodate the sedimentation patterns associated with the formation of the Step Graben and Central Graben during the Triassic and Jurassic, and later during Late Cretaceous and Cenozoic inversion tectonics.