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Badalini, Gianluca1, Jonathan Redfern2, Andrew Samuel3, Roger Heath4, Stuart Burley3, Nick Steel4, Ramadan Ramadan5
(1) University of Manchester, Manchester, United Kingdom
(2) North Africa Research Group, United Kingdom
(3) BG Group, Reading, United Kingdom
(4) Rashpetco, BG Group Plc, Cairo, Egypt
(5) BG Egypt,

ABSTRACT: Slope Channel Evolution: Near-Surface Depositional Processes Inferred from 3D Seismic Data, Offshore Nile Delta, Egypt

The West Delta Deep Marine (WDDM) Concession lies 50-100 km offshore of the present day Nile Delta. The water depth ranges between circa 200 and 2000 metres. The area contains the entire spectrum of stratigraphic elements of a siliciclastic submarine depositional system, and is renowned for an exceptionally well developed Pliocene slope channel system. High-resolution 3D seismic data has been used to reconstruct surface and near-surface depositional processes.
The most common features of the WDDM Concession seafloor are mass transport complexes (MTC's), channels, small diapirs, gas chimneys and sediment waves. MTC's cover large portions of the study area and mainly consist of debris flows; slides and slumps are also common. They appear to be sensitive to previous topography and tend to smooth the relief created by older sediments (for instance lows created by differential compaction).
Slope channels, although not common on the present day seafloor of the WDDM Concession, are extremely abundant in the subsurface. They show a variety of external geometries, fills, and evolutionary trends. Size varies greatly, from small channels presumably representing single sequence channels to large channels that may have been exploited over multiple 4th order sequences on the upper slope. Re-incision is extremely common and results in only partial preservation of "original" channels. Changes from relatively straight to sinuous channel paths can be observed at changes in slope gradient.
The high resolution dataset allows identification of the evolutionary trends in internal/external geometry, vertical stacking patterns and key intra-channel architectural elements, providing valuable analogues for older delta/slope systems.


AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.