Three-dimensional architecture and evolution of Quaternary contourite drifts on the Vøring Plateau, Norwegian Sea

Abstract

We use newly available, extensive two- and three-dimensional seismic datasets in the Vøring Plateau sector of the mid-Norwegan continental margin to investigate the architecture and evolution of Quaternary contourite drifts in the Norwegian Sea. The drifts typically comprise tens of cubic kilometres of sediment, often intercalated between lenses of glacigenic debris flows, and demonstrate migrating depositional centres along the upper and middle slope sectors of the mid-Norwegian margin through the last ~2.7 M.yr. By contrast, the contourite deposited in the southern Vøring Plateau area is anomalously large covering an area of ~17,000 km2 and comprising over 720 km3 of sediment. Correlation of internal drift surfaces with well-dated sediment cores shows that the massive, up to 280 m thick drift contains two major units that were deposited over the last two glacial-interglacial cycles, yielding extremely high sedimentation rates, comparable to those sourced directly from erosive meltwater-rich glaciers and fast-flowing ice streams. A revised evolutionary drift model provides an end-member example of how a combination of rapid glacially-derived sediment delivery and its subsequent transport and deposition by along-slope processes may exert considerable influence on continental margin morphology over geologically short timescales.