Tropical marginal seas host important sedimentary archives that may be
exploited to reveal past changes in continental erosion, chemical
weathering, and ocean dynamics. However, these records can be
challenging to interpret due to the complex interactions between climate
and particulate transport across ocean margins. For the southern South
China Sea over the last 90 kyr, we observe a contrasting temporal
relationship between the deposition of clay minerals and magnetic
minerals, which were associated with two different hydrodynamic modes.
Fine-grained clay minerals can be carried in suspension by ocean
currents, leading to a rapid response to regional climate-driven inputs.
In contrast, changes in magnetic mineralogy were associated with bedload
transport and resuspension, leading to a control by glacial-interglacial
sea-level variability. Overall, this study indicates that the transfer
pathways and mechanisms imparted by varying hydrodynamic conditions
exert a substantial influence on the distribution of terrigenous
material in continental shelf and margin sediments.