Multiple terraces within the deep incised Zaire Valley (ZaïAngo Project): are they confined levees?
N. Babonneau, B. Savoye, M. Cremer, M. Bez, 2004. "Multiple terraces within the deep incised Zaire Valley (ZaïAngo Project): are they confined levees?", Confined Turbidite Systems, S. A. Lomas, P. Joseph
Download citation file:
Terraces have been frequently observed and described along turbidite valleys. Many interpretations have been aimed at determining the origin of these structures, including a tectonic origin, succession of infilling and incision processes, channel-wall slumps, or inner levee aggradation. The Zaire submarine valley presents a complex structure with multiple terraces bordering a deep incised meandering thalweg. The detailed analysis of the morphology, the seismic structure and the recent sedimentation (in cores) along the Zaire upper-fan valley show that terraces are inner levees confined within the incised valley. Many terraces correspond to the infilling of abandoned meanders, and aggrade by deposition of turbidite sequences due to current overflows. The major process affecting the initiation and the development of terraces inside the valley is the vertical incision of the thalweg, simultaneously with meander migration.
Figures & Tables
This publication reflects a growing appreciation of the extent to which turbidite depositional system development is fundamentally affected by basin-floor topography. In the many turbidite and turbidite hydrocarbon reservoirs, depositional patterns have been moderately to strongly confined by pre-existing slopes; thus ‘submarine fans’ may be far from fan-shaped where constrained by significant bathymetric features. This volume examines aspects of sediment dispersal and accumulation in deep-water systems where sea-floor topography has exerted a decisive control on deposition, and explores the associated controls on hydrocarbon reservoir architecture and heterogeneity.
The papers presented here offer a global perspective, which is wide-ranging in terms of approach as well as location, including contrasting reviews and case studies of outcrop, subsurface, modern and experimental systems. This book will be of use both to academic geologists and to geoscience professionals in industry dealing with characterization and modelling of deep-water clastic reservoirs.