2022-10-11 null null null(卷), null(期), (null页)
The coastal sediments are sensitive carriers that reveal climate change, sea-level fluctuations, and monsoon evolution. A large number of sedimentary sequences developed along the coast of the Shandong Peninsula in the Last Glacial Period. Previous studies mainly focused on material sources and climate characteristics, but seldom mention the ten-thousand-year timescale monsoon evolution and its relationship with sea level fluctuations. The Liukuang section (LKS) is adjacent to the North Yellow Sea, which is mainly composed of alternations of dune sand and paleosol of the Last Glacial. Based on the chronological framework constructed by AMS C-14 and optically stimulated luminescence (OSL) dating, we measured grain size, geochemistry, and heavy minerals to reconstruct the evolution of the East Asian winter monsoon (EAWM) and climatic fluctuations during the Last Glacial Period. The variations of the climate proxy indicators show that the degree of dry-cold climate and EAWM strength are indicated by different sedimentary facies in dune sand > sandy paleosol > lacustrine > silty paleosol. On a ten-thousand-year timescale, we detected episodes of EAWM strengthened in the LKS4 (78.9-59.5 ka), LKS3b (50.5-39.6 ka) and LKS2 (29.7-13.1 ka), which correspond to Marine Isotope stage (MIS) MIS4, MIS3b and MIS2, respectively, and EAWM weakened in the LKS3c (59.5-50.5 ka) and LKS3a (39.6-29.7 ka), which correspond to MIS3c and MIS3a, respectively. These climatic events were essentially synchronous with climate changes recorded in the geological carriers such as the cave stalagmites of southern China, loess from the Chinese Loess Plateau (CLP), and sea-level fluctuations in the Yellow-Bohai Sea. It is believed that the external driving factor is from the changes of solar radiation, and the internal factor is mainly from the combined effect of monsoon changes and sea-level fluctuations.