Controls on the architectural evolution of deep-water channel overbank sediment wave fields: insights from the Hikurangi Channel, offshore New Zealand

Deep-water channels can be bound by overbank deposits, resulting from overspilling flows, which are often ornamented with sediment waves. Here, high-resolution bathymetry, backscatter, and 2D 3D seismic data integrated to discern the controls on flow processes areas of Hikurangi Channel. Qualitative interpretation quantitative analyses wave morphologies distributions conducted through shallowest 600 m stratigraphy up seafloor. Four outer-bend fields present throughout studied landward margin (left looking down-channel) only. Originally closely spaced or combined, these evolved become spatially separated; two separate became further subdivided into distinct outer- inner-bend fields, whose constituent waves developed differences in morphology distribution. Sediment character is used interpret direction strength flow. Nine such associated deposition identified: versus conduit size, gradient, tuning, Coriolis forcing, contour current activity, reflection, centrifugal interaction externally derived overspill different locations. Their relative importance may vary across parts areas, both temporally, controlling field development that: (1) only develop margin; (2) influence force overbanks has increased time, accompanying a general increase channel sinuosity; (3) form Coriolis-enhanced flow, outer-bank up-channel bends; (4) oceanward axial troughs, transverse, toward-channel component. This work implications for interpreting seafloor data, palaeogeographic reconstructions outcrop data.