Channel trajectories control deep-water stratigraphic architecture

Abstract

Interpretation of deep-water channel deposits is challenging because the spatial arrangement of their constituent lithologies is highly variable. This variability is often thought to be a signature of complex interactions between controlling boundary conditions and processes. A three-dimensional forward stratigraphic model of a sinuous meandering channel is used to explore the production of channelised deep-water stratigraphy. This model highlights three stages of stratigraphic evolution for channel belts: (1) an initial phase of rapid growth in mean belt width and variability in belt width driven by increasing channel sinuosity; (2) a subsequent phase of reduced belt-width growth rate because of cutoff processes; and (3) a mature phase during which repeated bend lifecycles act to produce a statistically stable channel-belt width. When a trajectory defining the vertical movement of a channel over time is added to the model, commonly recognised patterns of deep-water channel-belt stratigraphy are produced. These results demonstrate how forward stratigraphic models provide insights into processes governing the evolution of deep-water stratigraphy that elude interpretations of static outcrops and seismic images of subsurface examples.