The Eocene-late Pliocene paleoenvironment in the Vøring Plateau area, Norwegian Sea-paleoceanographic implications

From high-resolution and multichannel seismic data integrated with the relevant ODP and DSDP core sites, the sediments on the Vøring Plateau offshore mid-Norway was studied. Four seismic units were identified: units Vd (∼Eocene), Vc (∼Oligocene), Vb (∼Miocene-middle Pliocene) and Va (late Pliocene-Pleistocene). The history of sedimentation was controlled by two main factors; subsidence and deposition in deeper water as the study area moved away from the active mid-oceanic spreading ridge and the pattern and development of the ocean circulation system. During the Eocene, ocean-current-influenced sedimentation prevailed on the outer Plateau slope while shallow marine conditions prevailed on the inner parts. The Oligocene was dominated by ocean-current-influenced sedimentation on the northeastern, inner high which also affected the southern part from the early Miocene, coeval with renewed influence of ocean-current-controlled sedimentation on the outer slope. Sometime during the late Miocene to early Pliocene period a change to hemipelagic sedimentation occurred, indicating that the topographic control of the Vøring Marginal High on the ocean currents was reduced. The Paleogene ocean circulation system may have been interbasinal and restricted to the Norwegian-Greenland Sea or intrabasinal and connected to the North Atlantic: from our data, it is not possible to discriminate between the two alternatives. During the Neogene, the most important change was controlled by the subsidence of the Vøring Marginal High causing northeastward flowing water masses to flow along the shelf and slope of mainland Norway.