Cenozoic Seismic Stratigraphy of the Northern North Sea - The Application of Regional Scale 3D Data.

Methodology: Seismic interpretation using seismic- and sequence stratigraphic principles and well data. Calculations of thicknesses, volumes and accumulation rates using depth converted interpretations. Results/Findings: A depositional model confirming previous work. The post-rift subsiding northern North Sea Basin accommodated thick sedimentary successions. The sediments were supplied by progradation from the basin margins during periods of uplift and lowstand. Three regional erosional surfaces are related to uplift in the Palaeocene, Miocene and Pliocene-Pleistocene. The supply from the eastern basin margin created the largest sedimentary wedges in the Palaeocene, Pliocene and Pleistocene. During the Miocene deltas supplied sand to the Utsira Formation. Two large incised valleys formed from Western Norway into the Møre Basin prior to the onset of Pliocene progradation. Dramatically increasing accumulation rates in the Pliocene are thought to be related to glacial erosion and sediment supply from the Western Norway through the Sognefjord. The Palaeogene stratigraphy has been deformed by polygonal faulting and shale diapirism. The shale diapirs formed in the same time interval as the deposition of the Utsira Formation. The polygonal faulting is thought to have occurred prior to the diapirism. Implications: Established methodologies of seismic stratigraphy, sequence stratigraphy and shelf edge trajectories have been better constrained with 3D seismic data. Mapping and visualisation in 3D improves the evaluation of time and space relationships of geological events