Deep-water sedimentary systems: New models for the 21st century

One of the principal scientific, technical and environmental challenges for the next century is undoubtedly the exploration and understanding of the d eep oceans. Close collaboration between the hydrocarbon industry and scient ific community is allowing us to push back this frontier and so to develop new models for deep-water sedimentary systems. The turbidity current paradi gm is under scrutiny and refinements proposed for massive sands, megabeds a nd immature turbidites. Source area and sediment type are key controls. Bot tom currents play an important part in the shaping of margins, the generati on of hiatuses and bounding surfaces, the winnowing of sands and ventilatio n of ocean basins. It is at the level of architectural elements and their t hree-dimensional geometry that much activity is currently focused. Most adv ance has so far been made in terms of channel types, dimensions, aspect rat ios, stacking patterns and hierarchies; to a lesser extent this is true for lobes, levee complexes, contourite drifts and sheet sands. It is only afte r this phase of study that we will be able to significantly improve our mod els for the larger-scale systems-fans, ramps, slope-aprons, basin plains an d drifts. (C) 2000 Elsevier Science Ltd. All rights reserved.