Tectonics and Sedimentation in the Fold and Thrust Belts of the Deepwater Niger Delta
Freddy Corredor and John H. Shaw
Harvard University, Cambridge, MA
The fold and thrust belts of deep water Niger Delta are the product of contraction due to gravity-driven extension on the shelf of the passive margin of west Africa. Active folding and thrusting above a week detachment level is strongly influenced by local changes in rates of sedimentation above individual thrust sheets affecting the multiple stages of growth of fault-related folds (i.e. crest uplift or crest broadening), and the regional sequences of imbrication. The deep water Niger Delta offers an outstanding opportunity to describe and understand the patterns of growth sedimentation that result from multiple and complex kinematics, the relative timing of formation of individual thrust sheets within regional thrust systems, and the overall evolution of fold and thrust belts in passive margins. The interpretation and restoration of depth converted regional seismic sections across the fold and thrust belts of the deep water Niger Delta help to resolve the structural styles, the timing and sequences of thrusting, the relative changes in sedimentation across these systems, as well as the regional amounts of shortening, all of which have important implications for hydrocarbon maturation and charge in the deep-water Niger Delta. Shear and conventional imbricate fault-bend fold kinematics are invoked to model the tectonics of these systems, and the resulting patterns of growth sedimentation.