Late Palaeozoic – Mesozoic tectonostratigraphic development of the eastern Faroe-Shetland Basin: New insights from high-resolution 3D seismic and well data

Abstract

Abstract The Faroe-Shetland Basin (FSB) belongs to the sedimentary basins that encompass outer parts of the NE Atlantic continental margin. The FSB contains several kilometres thick Cenozoic and Cretaceous strata, which overlie poorly understood pre-Cretaceous strata. Regional high-resolution 3D seismic reflection data used in this study covers the eastern half of the basin, generally devoid of thick basaltic successions. The pre-Cretaceous successions are preserved as erosional remnants of originally more extensive deposits throughout the FSB. Devono-Carboniferous and Permo-Triassic rifting probably took place in the FSB, but the magnitude and regional extent of each phase is less constrained than in the neighbouring inner Hebrides-Shetland rift basins. Major rifting took place in Jurassic times and generated a fault-controlled marine basin. During the Apto-Albian and Cenomanian, distributed extension occurred throughout the FSB, suggesting wide rift mode of extension. The subsequent Campanian - Maastrichtian extensional phase, on the contrary, was localized in the Flett Sub-basin controlled by the Westray and Corona faults along its western margin and oppositely dipping faults along the eastern basin margin. The fault-controlled Cretaceous deposition in the FSB is a distinct feature that is documented in the basins along the mid-Norwegian margin but rarely recorded in other large Cretaceous basins along the NE Atlantic margin. In the FSB, Late Cretaceous faults frequently reactivated earlier structures, suggesting that a structural inheritance played an important role in basin development. The existence of Permo-Triassic evaporites is postulated to explain geometries of Jurassic and Lower Cretaceous strata and fault patterns in the Foula Sub-basin. A partial mantle serpentinization during Early Cretaceous times proposed for other outer basins along the NE Atlantic margin is unlikely to have occurred in the FSB.