Abstract The Late Cretaceous-Tertiary structural evolution of the northeastern part of the Vøring Basin, mid-Norway, is highly complicated. Although tectonic activity occurred throughout Cretaceous time in much of the Vøring Basin, including the Gjallar Ridge and along the Fles Fault Zone, in the Vema Dome-Nyk High area evidence of such activity is not observed until the latest Maastrichtian time. In the Vema Dome-Nyk High area, several faults with both a NW-SE orientation and a NE-SW orientation have experienced lateral movements. The NE-SW orientation is the old Caledonian trend. The complex structural evolution of the Vema Dome-Nyk High area is probably related to the existence of continental weakness zones, which are the onshore extension of known oceanic fracture zones. The two lineaments that delineate these weakness zones, and that delineate the Vema Dome-Nyk High area, namely the Bivrost and Surt Lineaments, diverge slightly from one another toward the SE. This complex structural framework of NW-SE oriented lineaments and NE-SW oriented deep-seated basement structures of Caledonian compressional and/or Mesozoic rift origin, facilitated minor clockwise rotation of the area between the two lineaments during the extensional regime before the break-up of the North Atlantic, as well as during the compressional regime that has been proposed after the break-up.

Abstract A new approach to constrain the Cretaceous and early Palaeogene depositional systems in the Vøring Basin has been achieved by combining 3D palaeobathymetry reconstructed from seismic sequence geometries, indicators of zero or shallow water depth, compaction and isostasy. The restorations were calibrated to known exposed intrabasinal highs. The Vøring Basin started out as a segmented and locally deep syn-rift basin during the Late Ryazanian. Water depths in the range 1000–2000 m have been restored in the deeper areas. In Late Cenomanian broader deep-water areas formed in the eastern part of the basin. The broadening of the basin was accompanied by shallower water depths during the Coniacian. A switch in basin configuration was fully established during the Early Campanian. The previously deep areas in the Rås and Træna basins became very shallow and the Vigrid and Någrind synclines started to subside, as a response to the reactivation of the Fles Fault Complex. The shallowing trend continued during Late Cretaceous time until regional uplift of the basin floor, and total emergence of the intrabasinal highs known as Gjallar Ridge, Vema Dome, Nyk High and Utgard High occurred around Maastrichtian-Paleocene time. This was followed by deepening in the Early Paleocene expressed in the depocentres, where the Vigrid and Rås basins now attained water depths of 300–400 m. Further increased subsidence occurred during the Late Paleocene, resulting in water depths up to 1000 m in the eastern Vøring Basin.

Abstract Along continental margins with rapid sedimentation, overpressure may build up in porous and compressible sediments. Large-scale release of such overpressure has major implications for fluid migration and slope stability. Here, we study if the widespread crater-mound-shaped structures in the subsurface along the mid-Norwegian continental margin are caused by overpressure that accumulated within high-compressibility oozes sealed by low-permeability glacial muds. We interpret 56 000 km 2 of 3D and 150 000 km 2 of 2D-cubed seismic data in the Norwegian Sea, combining horizon picking, well ties and seismic geomorphological analyses of the crater-mound landforms. Along the mid-Norwegian margin, the base of the glacially influenced sediments abruptly deepens to form 28 craters with typical depths of c. 100 m, areal extents of up to 5130 km 2 and volumes of up to 820 km 3 . Mounds are observed in the vicinity of the craters at several stratigraphic levels above the craters. We present a new model for the formation of the craters and mounds where the mounds consist of remobilized oozes evacuated from the craters. In our model, repeated and overpressure-driven sediment failure is interpreted to cause the crater-mound structures, as opposed to erosive megaslides. Seismic geomorphological analyses suggest that ooze remobilization occurred as an abrupt energetic and extrusive process. The results also suggest that rapidly deposited, low-permeability and low-porosity glacial sediments seal overpressure that originated from fluids being expelled from the underlying high-permeability and high-compressibility biosiliceous oozes.