Abstract Paleocene deep-water deposits of the Norwegian sector of the North Sea Basin are prospective for oil and gas, although little is known about their sedimentology and distribution, or the controls on their stratigraphic evolution. To help unlock the potential of this poorly explored interval, we integrate 3D seismic reflection, well logs and core data from the eastern North Viking Graben, offshore Norway. We show that thick (up to 80 m), high net to gross (N:G) (up to 90%), sandstone-rich channel-fills and sheet-like, likely lobe deposits occur on the slope–proximal basin floor, forming part of an aerially extensive fan system. Sediment dispersal and the resultant stratigraphic architecture are controlled by slope morphology. Bypass occurred on the northern, passive margin-type slope; whereas, in the south, sediment gravity currents were deflected around, and deep-water sandstones onlap and pinch-out onto an exposed rift-related fault block that generated intra-basin bathymetric relief. Pinchout of deep-water sandstone into mudstone suggests that future exploration should focus on identifying subtle stratigraphic traps on fault block flanks or at the fan fringe. This trapping style contrasts with that encountered in the UK sector of the Northern North Sea, where most Paleocene fields and discoveries are in structural traps related to the flow of Zechstein Supergroup salt.

Abstract In Magnolia Field, deepwater sediments were affected during deposition by allochthonous salt. Pleistocene channel systems developed on a salt flank and were initially deeply incised close to the salt but progressively avulsed down the lateral slope, each time with decreasing depth of incision. Following this degradational stage, a lobe developed on top of the channel fills and a large-scale aggradational system developed. A conceptual model of submarine channel development adjacent to active topography has been developed from this dataset. Channels may become deeply entrenched during stages of salt growth, but only where flow frequency and magnitude are sufficient to outpace topographic growth. Where flows are less frequent topographic growth may present a barrier to successive flows, causing avulsion. The large-scale cycles of salt growth and withdrawal commonly recognized in subsurface systems, combined with eustatic sea-level changes, may result in a cyclic style of evolution whereby channels initially become entrenched and/or step away from the growing topography, switching to backfilling as salt growth slows or pauses, followed by a distributive-style as the entire system backsteps. During salt withdrawal the equilibrium profile may become relatively raised and channels may develop an aggradational style. In these settings, significant cross-channel facies asymmetry may result.