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

Contrasting Fates of Petrogenic and Biospheric Carbon in the South China Sea

“…Proxies such as bulk OC isotopes and even biomarkers such as alkanes, which may be of petrogenic origin, should therefore be interpreted with caution given that they may partially reflect bedrock signatures in addition to commonly extracted information about continental vegetation (Zhou et al, ) and atmospheric CO 2 content (Kienast et al, ). The negligible input of terrestrial biospheric OC in the modern SCS may contrast sharply to glacial periods when lower sea level permitted greater terrigenous export into the OC into the deep SCS (Zhao et al, ). For example, increases in kaolinite contributions during the most recent glacial period mark heightened contributions from the Chinese mainland (Liu, Li, et al, ) that likely coincide with elevated pedogenic OC contributions, which evaded trapping on the shelf and margin areas.…”

Responses of the East Asian Summer Monsoon in the Low‐Latitude South China Sea to High‐Latitude Millennial‐Scale Climatic Changes During the Last Glaciation: Evidence From a High‐Resolution Clay Mineralogical Record

“…Being further in combination with the average value of terrigenous fluxes (4.48 g · cm À2 · ka À1 ) at Core MD12-3434 (S. H. Zhao et al, 2017), the averaged terrigenous flux from Luzon during interglacials is estimated to be 0.76 g · cm À2 · ka À1 . Similarly, the averaged terrigenous flux from Luzon during glacials is estimated to be 0.54 g · cm À2 · ka À1 (an average contribution of 10% from Luzon versus an average terrigenous flux of 5.36 g · cm À2 · ka À1 ; S. H. Zhao et al, 2017). Obviously, the terrigenous fluxes from Luzon during interglacials are higher than that during glacials, confirming that a higher sediment contribution sourced from Luzon inferred from higher εNd values and lower 87 Sr/ 86 Sr ratios also implies an increased terrigenous fluxes.…”

“…In particular, owing to differential settling and/or flocculation, the relatively coarser-grained kaolinite from South China flocculates and settles fast when encountering the alkaline seawater Schroeder et al, 2015). During the glacial periods (MIS 2 and 4), the drop of sea levels led to the seaward migration of the paleo-river mouth, causing more South China-sourced terrigenous sediments to be transported to the area of Core MD12-3434 (S. H. Zhao et al, 2017). Luzon-sourced sediments (principal fine-grained smectite) are carried mainly by the westward surface currents with significant influence of the Kuroshio intrusion through a long transport distance .…”

“…L. Zhao et al, 2015). During the glacial periods (MIS 2 and 4), the drop of sea levels led to the seaward migration of the paleo-river mouth, causing more South China-sourced terrigenous sediments to be transported to the area of Core MD12-3434 (S. H. Zhao et al, 2017). This mechanism could explain the slight increase of kaolinite during the glacial periods (from MIS 4 to MIS 2; Figure 2).…”

“…For glacial sediments (MIS 2 and 4), lower εNd values and higher 87 Sr/ 86 Sr ratios imply a higher contribution of sediments provided by Taiwan and/or South China. Considering the synchronously increased terrigenous fluxes at Core MD12-3434 (S. H Zhao et al, 2017),. this higher sediment contribution has indeed indicated the significant increased terrigenous fluxes from Taiwan and limited increased terrigenous fluxes from South China because of its overall minor contribution.…”