Deltas: a new classification expanding Bates’s concepts

Abstract Deltas constitute complex depositional systems formed when a land-derived gravity-flow (carrying water and sediments) discharges into marine or lacustrine standing body of water. However, the complexity deltaic sedimentary environments has been oversimplified by geoscientists over years, considering just littoral deltas as unique possible type delta in natural systems. Nevertheless, rational analysis suggests that can be much more complex. In fact, characteristics deposits will depend on interplay between bulk density incoming flow salinity receiving body. This paper explores conditions sedimentation according to different contrasts. The allows recognize three main fields for sedimentation, corresponding (1) hypopycnal (2) homopycnal (3) hyperpycnal settings. field represents situation is lower than basin. According body, types are recognized: hypersaline (HSLD), (MLD), brackish (BLD). basin determine capacity producing effective buoyant plumes, consequently extension prodelta deposits. Homopycnal (HOLD) form roughly similar typical clean bedload-dominated rivers entering freshwater lakes. Delta front dominated sediment avalanches. Typical fallout absent poorly developed since no plumes generated. Hyperpycnal higher interaction type, (due concentration suspended defines deltas, (HLD), subaqueous (HSD), fan (HFD). low-gradient shallow-water dirty enter normal-salinity basins, typically wave tide-dominated epicontinental seas represent most common delta, with channels lobes generated settings during long-lasting sediment-laden river-flood discharges. Finally, high-gradient episodic high-density fluvial