Sedimentological signatures of river-shelf processes in a wave-dominated delta front

A wave-dominated delta depositional model is characterized by the combined action of riverine-induced processes and sediment reworking by waves and currents. The combination of these natural-driven processes will lead to the formation of a delta-associated sedimentary record that can potentially register changes in prevailing oceanographic and hydrological conditions, including episodic or extreme events, and also anthropogenicinduced changes to the watershed and sediment load. The main objective of this study is to recognize the sedimentological signatures associated with distinct riverine-inner shelf processes in a wave-dominated delta setting. The study is based on high resolution grain size investigation, applying a grain size x standard deviation analysis. The results allowed to differentiate a typical riverine sediment deposit from the sedimentological signature of episodic or more responsive events related to higher flooding and storm-induced wave/current processes. The delta-associated inner shelf deposits vary according to their distance and orientation from the river mouth and water depth (south-north). This indicates that inner shelf sedimentary records show the spatial influence of riverine plume dispersion/deposition, and marine processes (waves resuspension, coastal currents and tides). These results can be considered for analogue model studies, but also to a first assessment related to medium to long term sedimentation pattern and riverine particulate contaminant dispersion and deposition.

Automated summary

A wave-dominated delta depositional model is characterized by the combined action of riverine-induced processes and sediment reworking by waves and currents. The results of the study indicate distinct sedimentological signatures associated with riverine-inner shelf processes and episodic or responsive events. The spatial influence of riverine plume dispersion/deposition and marine processes on delta-associated inner shelf deposits is also evident.