Quaternary evolution of the northern North Sea margin through glacigenic debris‐flow and contourite deposition

Abstract

ABSTRACTThe Norwegian Channel Ice Stream of the Scandinavian Ice Sheet extended across the northern North Sea margin during the mid‐ to late Quaternary, eroding older sediment from the continental shelf. Consequently, little is known about early Quaternary sedimentation on this margin. We use two‐ and three‐dimensional seismic‐reflection data to investigate changing sediment volumes and sources in the northern North Sea through the Quaternary. The northern North Sea Basin was infilled during the early Quaternary by intercalated glacigenic debris‐flows and contourites, which provide a record of the delivery of glacigenic sediment to the slope and the intensity of North Atlantic thermohaline circulation during early Quaternary glacial–interglacial cycles. The infilling of the basin reduced accommodation and led to the deflection of mid‐ to late Quaternary sediments into the Norwegian Sea, forming the North Sea Fan. Close to the onset of the mid‐Quaternary, the south‐western Scandinavian Ice Sheet margin was drained by an ice stream located beneath Måløy Plateau, 60 km east of the Last Glacial Maximum Norwegian Channel Ice Stream. The southward‐flowing Norwegian Sea Bottom Water current was directed into the partially filled northern North Sea Basin during the early Quaternary, and deflected progressively northwards as the basin became infilled.