New statistical quantification of the impact of active deformation on the distribution of submarine channels

Submarine channel systems play a crucial role in governing the delivery of sediments and pollutants such as plastics from the shelf edge to deep water. Understanding their distribution in space and time is important for constraining the locus, magnitude, and characteristics of deep-water sedimentation and for predicting stratigraphic architectures and depositional facies. Using three-dimensional seismic reflection data covering the outer fold-and-thrust belt of the Niger Delta, we determined the pathways of Miocene to Pliocene channels that crossed, at 173 locations, 11 fold-thrust structures for which the temporal and spatial evolution of strain rates has been constrained over a period of 11 m.y. We use a statistical approach to quantify strain and shortening rate distributions recorded where channels have crossed structures compared to the fault array as a whole. Our results prove unambiguously that these distributions are different. The median strain rate where channels cross faults is <0.6%/m.y. (~40 m/m.y.), 2.5× lower than the median strain rate of active fault segments (1.5%/m.y.) with a marked reduction in the number of channel-fault crossings where fault strain rates are >1%/m.y. Our results quantify the sensitivity of submarine channels to active deformation at a population level for the first time and enable us to predict the temporal and spatial routing of submarine channels affected by structurally driven topography.