Paleoclimatic evolution and weathering in the Northern South China Sea during the last 61 kyr BP--Sedimentary records from the coastal zone

Abstract

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.

Deep-water circulation intensity and stratification in the South China Sea since the last glaciation

“…Chronology of Core MD05-2905 and ODP Site 1144 were established respectively based on 12 and 7 accelerator mass spectrometry (AMS) 14 C dating points of planktonic foraminifera (Globigerinoides ruber, Globigerinoides sacculifer or mixed planktonic foraminifers) (Table 1; Bühring et al, 2004;Yang, 2008). To obtain the calendar ages of AMS 14 C dating points, the conventional radiocarbon ages were recalibrated by the program Calib 8.1.0 (Stuiver and Reimer, 1993), using the Marine20 calibration dataset (Heaton et al, 2020) and a ΔR value of -87±48 (regional mean of the South China Sea) (Southon et al, 2002;Yoneda et al, 2007).…”

“…Journal Pre-proof level during the Holocene, while LSR of ODP Site 1144 were around 2-4 times higher than Core MD05-2905 during the last glacial period (Figure 2). (Bühring et al, 2004;Yang, 2008).…”

“…Depth-age plots and linear sedimentation rates (LSR) of Core MD05-2905 and ODP Site 1144. The magenta solid circles show the AMS 14 C dating points(Bühring et al, 2004;Yang, 2008).…”

“…The pseudo-color plots show the changes in grain-size frequency distribution of particles <63 μm. δ 18 O stratigraphy of planktonic foraminifera Globigerinoides ruber and the radiocarbon dating points (the inverted triangular marks in magenta) of Core MD05-2905 and ODP Site 1144 are fromYang (2008) andBühring et al (2004), respectively. The Roman numerals indicate the three stages of grain-size evolution in each core.…”