Lithogenic fluxes in the Bay of Bengal measured by sediment traps

Lithogenic flux measured continuously for 1 year using time-series sediment traps at two sites in the Bay of Bengal show a strong seasonality with 43–49% of the fluxes to the deep traps occurring during the SW monsoon. Lithogenic fluxes increased with depth and the rate of increase was maximum during periods of high freshwater influx. Simultaneous sedimentation of lithogenic and organic matter is seen at both the sites. Clay mineral studies show that illite percentage decrease and smectite percentage increase with depth. Due to the prevailing circulation pattern, illite-rich suspended sediments from the Ganges-Brahmaputra Rivers are transported southwards in the surface low salinity layer while smectite-rich muds from the continental margins are resuspended and transported at depth in perhaps somewhat heavier clock-wise circulation.