Astronomical dating of Quaternary strata in the South Yellow Sea and its indication for paleoclimatic evolution

The continental shelf has experienced high-frequency transgression-regression cycles during the Quaternary, and its sediments have stored significant information on sea-level changes, climate fluctuations and regional tectonic activities. Due to the lack of extended core records and high-resolution stratigraphic chronology, the strata correlation between continental and marine basin since the Quaternary still has considerable limitations. Here, we present a high-resolution grain size and geochemical study of core CSDP-1 (similar to 3.5 Ma) recovered from the western South Yellow Sea (SYS), China. Two sensitive components were extracted from sediments, and their contents can be used to reflect the paleo-hydrodynamic intensity and reconstruct paleoclimate change. A comprehensive analysis including lithologic characteristics of sediments and seismic data interpretation, shows that the stratum deposition at the borehole's location is relatively continuous at the orbital time-scale. The results of spectral analysis, show that the fine sensitive component it records the periodic change information of the Earth's orbital parameters (similar to 400-, 100-, 40-, and 20-kyr), and the astronomical chronology was established successfully. The variations of sensitive components in the sediments reveals that the SYS paleoclimate has undergone four periods since the Quaternary: cold conditions during 2.58-2.49 Ma and 1.88-0.83 Ma, warm and humid conditions during 2.49-1.88 Ma and 0.83-0 Ma. Moreover, the stratum in the SYS shelf records the Middle Pleistocene climate transition (MPT). It is inferred that the MPT in the SYS is mainly manifested by the enhancement of the 100-kyr period related to the synchronous forcing of the similar to 400-kyr eccentricity.

Automated summary

The study of core CSDP-1 from the western South Yellow Sea in China reveals the paleoclimate changes and sea-level variations since the Quaternary. By extracting sensitive components and establishing astronomical chronology, four distinct paleoclimate periods and the Middle Pleistocene climate transition were identified in the sediments from the continental shelf.