Sediment source-sink processes and sedimentary pattern in the Bengal Fan since the Last Glacial Maximum

Understanding the response mechanisms of terrestrial matter from source to sink under global warming is crucial for predicting the carbon cycle and assessing coastal risks. This study integrates multiple records to comparatively analyze the source-sink processes of the Bengal Fan during the Last Glacial Maximum (LGM) and the Holocene. The results show that: (1) Spatiotemporal heterogeneity of sediment sources: The Himalayan source dominates in the northern part and the turbidity channel, while mixed sources are found in the western (near the Indian Peninsula) and eastern (near Myanmar) areas, with an increased contribution from the Indian Peninsula during the Holocene compared to the LGM; (2) Spatially variable sedimentary rate: it is overall higher during the LGM (sea level control), but the “T-shaped” area on the western Bay of Bengal shows a higher rate during the Holocene (Indian monsoon control); (3) a “dual-channel” transport mode: prevalent turbidity currents during the LGM, surface currents (enhanced southwest monsoon and East Indian Coastal Current) dominating Indian Peninsula/Myanmar material dispersal during the Holocene. These findings highlight that sea level changes, via shelf trapping and turbidity activity, dominate sedimentary flux, while monsoon intensity, via source erosion and circulation, regulates sediment distribution, shaping the Fan’s glacial-interglacial sedimentary pattern.