LITHOGENIC FLUXES TO THE DEEP ARABIAN SEA MEASURED BY SEDIMENT TRAPS

Particle fluxes measured continuously for one year at three locations in the Arabian Sea using time-series sediment traps show that lithogenic sedimentation processes are strongly coupled to biological processes. The vertical flux of lithogenic matter is controlled by episodic production and fluxes of biogenic matter. Illite and quartz are the dominant clay minerals in the traps at all three locations. Smectites generally range between 2 and 8%, but show higher fluxes up to 25% in the central and eastern Arabian Sea during the southwest monsoon period. Most of the river discharge is retained on the continental shelf, and less than 5% of the annual input of lithogenic material to the Arabian Sea is deposited in the deeper part as hemipelagic sediments.