Changjian Xia

Marine sediments in coastal zones serve as valuable archives for understanding the history of silicate chemical weathering and summer monsoon rainfall in source areas, providing insights into terrigenous climate and environmental evolution. In this study, we investigated the grain size, clay minerals, and geochemistry of sediments retrieved from core KZK01 in the coastal zone of the northwest South China Sea during the past 13 thousand years before present (kyr BP). Our findings demonstrated that the illite crystallinity index served as a reliable proxy for assessing the intensity of chemical weathering in the source area. Moreover, it distinctly recorded significant climatic events such as the Younger Dryas and Bond events during the Holocene. The dominant driver of the regional East Asian summer monsoon was identified as summer solar radiation in the Northern Hemisphere at low latitudes. Cold climate events exhibited global consistency, potentially influenced by the presence of ice sheets at high latitudes. Lastly, our records revealed a distinct transition at 9.0 kyr, highlighting significant impacts of the Qiongzhou Strait and sea level rise on regional climate dynamics.

The history of silicate chemical weathering is recorded by Marine sediments in the west coastal zone, contains the information of terrigenous climate and environment evolution.in order to constrain the Proxy index and driving mechanism of summer monsoon intensityof the sediments from this core since ~61 Kyr BP, the grain size, clay minerals and elemental geochemistry of sediments from core KZK01 in the coastal zone of the Northern South China Sea have been analyzed. The results showed that the illite crystallinity and smectite/(illite+chlorite) not only reflects the intensity of surface chemical weathering in the source area, but also clearly records the Heinrich event (H5), Younger Dryas event and the cold events since the Holocene, such as 8.2 Ka, 4.2 Ka and 2.8 Ka.The regional East Asian summer monsoon is mainly driven by the summer solar radiation at low latitudes in the northern hemisphere,Cold climate events have a global consistency and may be related to the global impact of high-latitude ice sheets.The paleoclimatic changes since 61 Kyr BP in the Northern South China Sea can be divided into 61kry BP~59.5kry BP、59.5kry BP~49.5kry BP、49.5kry BP~40.5kry BP、and 40.5kry BP~11.5kry BP、11.5kry bp~2 kry BP and 2kry BP to present six stages.In different stages of climate evolution, the alternating characteristics of cold, dry, warm and wet are obvious, with significant stages.