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Sediment cores from the Ganges–Brahmaputra delta in Bangladesh were examined for sedimentological character, clay mineralogy, elemental trends (C, N, S), and ¹⁴C geochronology to develop a model for the sedimentary sequence resulting from lower delta plain progradation in the late Holocene. A widespread facies succession from Muddy Sand to Interbedded Mud records progradation of shoal–island complexes and the transition from subtidal to intertidal conditions. Mangrove-vegetated islands and peninsulas represent the final phase of progradation; a Mottled Mud that is deposited by penetration of turbid coastal water into the mangroves during high water events. Organic matter preservation is generally low (<1% TOC) in most of these well-drained deposits that are characterized by a permeable, silt-dominated granulometry. Clay mineralogy in the cores records the relative influence of smectite and …