Reconciling bathymetric and stratigraphic expressions of submarine channel geometry

Modern submarine channels form distinctive morphological features on the seafloor and play a critical role in shaping marine sedimentary record. Recent studies have captured extremely diverse range of cross-sectional geometries from bathymetric data, which typically display aspect ratios markedly different to stratigraphic record ancient channels. Here, we compare reconcile relationship between geomorphic expression as observed geometry their bodies mapped seismic-reflection using Niger Delta slope an exemplar. For same channels, our data allows us contrast distribution widths, depths, at two hierarchical scales underlying stratigraphy – channel element system scale. Channel characteristics are also contextualised with respect key variables, structural template relative timescale for studied systems been active. Analysis bankfull highlights substantial variability widths ranging ∼300 m ∼4 km ∼10:1–100:1. In contrast, remains remarkably consistent across three ∼480–620 ∼9:1. At scale width is comparable that seen but 6–23:1. Our results therefore highlight marked disparity present-day associated We demonstrate large part modern may be explained by post-abandonment modification seabed where there reduced Holocene activity argue this effect likely plays differences global sets. These significant implications use process analogues when applied estimate flow characteristics.