Spatiotemporal variations of deep-sea sediment components and their fluxes since the last glaciation in the northern South China Sea

Sediment components and their fluxes of Cores MD12-3428 (water depth: 903 m), MD12-3433 (water depth: 2125 m), and MD12-3434 (water depth: 2995 m), obtained along a transect on the continental slope of the northern South China Sea, have been conducted to reveal the spatiotemporal variations and the controlling factors of the sediment components and of their fluxes. Results show that deep-sea sediments in the northern South China Sea are composed mainly of terrigenous (59-89%) and carbonate (6-38%) particles, with minor components of opal (1.6-9.4%) and organic matter (0.7-1.9%). Fluxes of terrigenous and carbonate particles reach up to 2.4-21.8 and 0.4-6.5 g cm(-2) kyr(-1), respectively, values that are one to two orders of magnitude higher than the fluxes of opal and organic matter. Temporal variations of the percentages and fluxes of deep-sea sediment components have displayed clear glacial-interglacial cyclicity since the last glaciation. Terrigenous, opal, and organic matter percentages and their fluxes increas clearly during marine isotope stage 2, while carbonate percentages and fluxes show an opposite variation pattern or are characterized by an unremarkable increase. This implies that deep-sea carbonate in the South China Sea is affected by the dilution of terrigenous inputs during the sea-level lowstand. With increasing water depth along the transect, the terrigenous percentage increases but with largely decreased fluxes. Both the percentage and flux of carbonate decrease, while the percentages and fluxes of opal and organic matter display much more complicated variational features. The spatiotemporal variations of deep-sea sediment components and of their fluxes since the last glaciation in the northern South China Sea are strongly controlled by sea-level fluctuations. Simultaneously, terrigenous supply associated with monsoonal rainfall, marine primary productivity, and the dilution effect between terrigenous and biogenic particles, also play interconnected roles in the sediment accumulation processes.