Fluvial sand, Amazon mud, and sediment accommodation in the tropical Maroni River estuary: Controls on the transition from estuary to delta and chenier plain

The Maroni River, South America, is a tropical estuary encased in narrow lower valley with limited area of estuarine tidal flat development, and displays channel large downstream-migrating sandy bedforms linked to sand-filled shallow mouth. sand-rich nature the River reflects significant fluvial bedload supply, among rivers lowest suspension-sized sediment load world. During dry season, shows high suspended concentrations near bottom (several g/l) that are due ingress mud streaming alongshore from Amazon delta. However, expelled during high-discharge rainy-season, seems be essentially restricted this seasonal intrusion along main little net sedimentation because overbank accommodation space. Sand actively supplied by coast has been diverted wave-generated longshore transport westwards, towards Suriname coast. This resulted construction numerous cheniers within muddy coastal plain built mud. sediment-source dichotomy an important original feature Guiana Shield estuaries. asymmetric progradation at mouth fingerprints westward growth, vicinity river mouths, muddy, chenier-studded, Guianas. propensity for these supply sand coast, eventually evolving into deltas, depends on ability their estuaries limit (downdrift) deflection long-term updrift sedimentation. tended evolve delta both mud, stage, Rivers, only Essequibo Guyana achieved. Further studies will needed order constrain infill pattern its