Sedimentary environmental evolution for the past 30 ka of the northern continental slope of the South China Sea

The South China Sea is the largest marginal sea in the Western Pacific, which receives massive sediments from the surrounding landmasses. Terrestrial sediments are transported into the deep basin via a complex ocean current system, with the continental slope as a key component of the source-to-sink process. However, past changes in sedimentary environment of the continental slope remain rarely understood, because of the drastic variations in water depth and complicated current systems in addition to sea level changes induced by glacial-interglacial cycles and the changes in trade wind. In this research, two gravity cores collected from the northern South China Sea are used to study the sedimentary environmental evolution of the continental slope. One is located in the middle of the slope, and the other at the lower part of the slope. According to the results of element geochemistry, it is revealed that: 1) the sea level change is the key factor which controls the changes in the ratio of terrigenous to biogenic components of the sediments; 2) a carbonate dilution event is found related to the intensification of the East Asian Summer Monsoon during the early Holocene from 11.5 to 8.5 kaBP.