Evaluating the Mis-match between Compression and Extension in Deep Water Fold Belts; Insights from the Namibian Passive Margin

To date much exploration on passive margins has centred on shallow water targets but as technology and demand increases deepwater settings are becoming increasingly important. A key component of deep water plays are gravity collapse systems that comprise extensional domains in the up dip portion and compressional structures in the down dip portion. These systems have been recognised on a number of continental margins and are economically significant, often containing petroleum plays in both domains.

It has often been assumed that these systems structurally balance, with the down dip compression balancing that of the updip extension. Recent studies, however, argue that this assumption is invalid. In this study we investigate regional scale sections from the Namibian margin that illustrate a spectrum of styles of deformation from a) areas that have very little compression despite the presence of extension; to b) well developed coupled systems; to c) more complex systems where extension is coupled to multiple down dip compressional complexes. In all cases extension is not balanced by compression and we discuss the possible causes of this, and implications for exploration in deep water systems.

AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California