Neogene and Quaternary depositional environments on the Norwegian continental margin, 62°N–68°N

Abstract

2D multichannel seismic and mini-sleeve gun profiles reveal that an up to 1.5 s(twt) thick sedimentary succession has been deposited on the Norwegian continental margin (62°N–68°N) during Neogene and Quaternary. Well-defined Miocene depocentres have evolved both in the North Sea Fan region and along the flanks of structural highs in the Vøring Basin. Miocene sediments are, on the other hand, mainly absent within the Storegga Slide scar. Seismic facies analyses show that these deposits locally are characterised by a mounded and/or migration–aggradation pattern, which we relate to a current-influenced depositional environment. Hence, the early Neogene sediments on the Norwegian continental margin are classified as contourites. The contourites have most likely been deposited in connection with the establishment of a deep-water exchange in the Norwegian–Greenland Sea, due to the opening of the Fram Strait and subsidence of the Greenland–Scotland Ridge. At about 2.5 Ma, a significant change in this depositional environment took place. Down-slope sedimentary processes became now more important and throughout the late Plio-Pleistocene sediments were mainly sourced from the Norwegian mainland and the adjacent continental shelf, causing depocentres to evolve along the shelf edge.