Concept of equilibrium profile in deep-water turbidite systems: effects of local physiographic changes on the nature of sedimentary process and the geometries of deposits
Published:January 01, 2005
J-N. Ferry, T. Mulder, O. Parize, S. Raillard, 2005. "Concept of equilibrium profile in deep-water turbidite systems: effects of local physiographic changes on the nature of sedimentary process and the geometries of deposits", Submarine Slope Systems: Processes and Products, David M. Hodgson, Stephen S. Flint
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In the middle slope section of the Lower Congo Basin a late Miocene channel system was tracked on 3D seismic profiles over more than 350 km. Along its course, between shelf and basin, the system encountered four regional tectonic structures that induced local slope modifications, either by uplift or by subsidence. The turbidite deposits of this channel system were influenced strongly by these structures, in terms of both character and morphology. From the proximal to the distal part of this channel system, variations in parameters such as the sinuosity, the width and depth of basal incision, the presence of splay and levee deposits, the location of vertical aggradation zones and channel avulsion, all correlate with changes in longitudinal slope gradient. Thus, along a conventional sigmoidal slope, the convex regions are subjected to erosional processes whereas the concave regions are depositional. The direct relationship observed between sedimentary deposits and changing slope gradient highlights an important control in deep-water turbidite systems. This apparent response to local gradient changes on the slope suggests the existence of a sedimentary equilibrium profile similar to that defined for fluvial systems.
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Submarine Slope Systems: Processes and Products
Submarine slopes provide the critical link between shallow-water and deep-water sedimentary environments. They accumulate a sensitive record of sediment supply, accommodation creation/destruction, and tectonic processes during basin filling. There is a complex stratigraphic response to the interplay between parameters that control the evolution of submarine slope systems, e.g. slope gradient, topographic complexity, sediment flux and calibre, base-level change,tectonic setting, and post-depositional sediment remobilization processes. The increased understanding of submarine slope system has been driven partly by the discovery of large hydrocarbon fields in morphologically complex slope settings, such as the Gulf of Mexico and offshore West Africa, and has led to detailed case studies and improved generic models for their evolution. This volume brings together research papers from modern, outcrop and subsurface settings to highlight these recent advances in understanding of the stratigraphic evolution of submarine slope systems.