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Sediment-Structure Interactions in Deep-Water Fold Belts: The Relationship between Submarine Channel Deposition and Growth Sequence Architecture

Clark, Ian 1; Cartwright, Joe 1
1 Earth, Ocean and Planetary Sciences, Cardiff University, Cardiff, United Kingdom.

Understanding the structural control on sedimentation in deepwater settings is a key factor in the prediction of reservoir architecture where submarine channel systems are present. The aim of this study is to consider the detailed interactions between submarine channels and folds in the context of larger scale growth sequences adjacent to fold limbs which host these systems. 3D seismic data from the Levant Basin, Eastern Mediterranean, provides an ideal opportunity to study coeval deformation and submarine channel deposition in an active fold belt setting. Growth sequences developed on the backlimbs and forelimbs of the folds in this area record changes in the relative rates of sedimentation versus uplift during fold growth. Growth sequences can be used to constrain the evolution of bathymetric relief during fold growth and we demonstrate that this can have a profound influence on the development and morphology of submarine channel systems. Two end member models are presented:

1. Sedimentation rate exceeds uplift: This results in little or no seafloor expression of the fold during deformation. Submarine channels typically flow perpendicular to the strike of the fold, but may show subtle changes in channel morphology (such as a change in sinuosity) caused by loss of accommodation space across the fold crest.

2. Uplift exceeds sedimentation rate: This results in positive relief developing at the seafloor causing deflection and diversion of submarine channel systems around the emerging fold.

Throughout fold growth the relative rates of sedimentation and uplift can vary, causing a transition between the two end-members and resulting in a complex vertical sequence of submarine channels becoming incorporated into the growing fold. The results of this study demonstrate that the response of submarine channels to uplift during fold growth can be assessed by careful consideration of growth stratal architectures. This can provide useful information relating to potential development of reservoir sands or lack thereof, as well as constraining the evolution of bathymetric relief during fold development.

 

AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009