Northern Barbados accretionary prism: Structure, deformation, and fluid flow interpreted from 3D seismic and well‐log data

Abstract

We reanalyzed 3D seismic reflection and logging-while-drilling data from the toe of the northern Barbados accretionary prism to interpret structure, deformation, and fluid flow related to subduction processes. The seafloor amplitude and coherence reveal an abrupt change in the thrust orientation from NNE at the thrust front and north and NNW about 5 km west of the thrust front. These thrust sets are separated by a triangular-shaped quiet area, which may represent a zone of low strength. The northeast-trending band of strong negative amplitude and high coherence in the décollement, known to be an interval of arrested consolidation, overlaps the quiet area, suggesting that the arrested consolidation may be related to the lack of thrust imbrication, and thus, vertical drainage for fluid in the accretionary prism. Fractal analysis of the décollement and top of the subducting oceanic basement indicates that the relief of the décollement correlates with the topography of the oceanic basement. Differential compaction of the underthrust sediment overlying the rugged oceanic basement, together with the basement faults that penetrate into the décollement probably caused relief or even faulting in the décollement.