Deep structural development of the NW Dutch North Sea

Abstract

The North Sea has a long history of tectonic activity. It contains multiple hydrocarbon fields. Therefore many explorations and researches have been conducted across the area. However, limited information is available on the sub-Zechstein salt sediments and tectonic evolution of the Dutch North Sea sector. Studies have relocated the Avalonia and Baltica plate tectonic margins. This will influence the tectonic evolution of an area. The margin is relocated near the Step and Dutch Central Graben. This report discusses the tectonic evolution of the area north of the Cleaverbank Platform, the Elbow Spit High, North Elbow Basin, and the Step Graben from the Late Silurian to Carboniferous Period. An interpretation has been conducted by the use of the NSR seismic survey data and the creation of new structural maps. The oldest observed structural development of the research area is the NE-SW oriented Late Silurian-Early Devonian normal fault systems. NE-SW extension by back-arc extension of the Caledonian orogen occurred from the Lower to Upper Devonian. The tectonic regime changed to E-W oriented during the Variscan Orogeny and the Lower Devonian intramontane basins were filled with Upper Devonian Old Red Sandstones. E-W extension continued through the Lower Carboniferous, while the southern part was exposed to Variscan deformation. The end of the Variscan Orogeny is marked by the formation of N-S oriented half-grabens in the Upper Carboniferous.