Tectonic controls on basin physiography and sediment dispersal: the Vana Sub-basin, northern North Sea

Abstract

A number of studies have investigated the controls on syn-rift sedimentation patterns and shift in syn-rift depocentres in rift-basins. However, few studies are focusing on how the change in tectonic regime that comes with the transition from syn-rift to post-rift has implications for the way depocentres are formed and how sedimentary systems respond to basin physiography. This study includes a 3D seismic survey covering the Vana Sub-basin, located in the northern North Sea. The seismic survey is used for seismic interpretation of stratigraphic intervals of Upper Jurassic to early Upper Cretaceous age. These intervals are used in order to construct chronostratigraphic Wheeler diagrams. Generation of TWTT thickness maps based on two interpreted horizons displays the interval’s depocentre location. Based on a series of interpreted stratigraphic intervals a history of shifts in depocentre location is revealed. A comparison of generated TWTT structure-, TWTT thickness maps, and constructed Wheeler diagrams are conducted to explain shifts in location of depocentres through time. An analysis of the depocentre shifts through time in the Vana Sub-basin shows that the downthrown VSCF hanging wall topography was not filled in before the deposition of the Mid Aptian-Albian Rødby+Sola formations. The analysis also shows that the Upper Jurassic structural configuration was influencing the sediment distribution until the deposition of the Upper Cenomanian – Lower Turonian Blodøks formation.