Changes in Sediment Sources in the Southern Muddy Area of Weihai, China, Since the Late Pleistocene: A Record from Rare Earth Elements

The small muddy areas developed in the southern Shandong Peninsula have attracted increasing attention from researchers because of complex changes in sediment sources driven by sea-level fluctuations and land-sea interactions since the late Pleistocene. This study investigates the evolution of sediment sources and their responses to environmental changes since the late Pleistocene, using core WHZK01 collected from the nearshore muddy area in southern Weihai for rare earth element (REE) analysis. In doing so, this work highlights the changing patterns of material sources and the primary control factors. The results reveal that the sedimentary deposits in core WHZK01 exhibit distinct terrestrial characteristics. Discriminant function analysis (FD) and source discrimination diagrams both suggest that the primary sources of these deposits are the Yellow River and adjacent small and medium-sized rivers, although the sources vary among different sedimentary units. Furthermore, the DU3 layer (17.82-25.10 m) displays typical riverine sedimentation, dominated by terrestrial detrital input, primarily from the local rivers, namely the Huanglei and Muzhu Rivers. The material in the DU2 layer (14.91-17.82 m) is mainly influenced by a mixture of the Qinglong and Yellow Rivers. The DU1 layer (0-14.91 m) is influenced by sea-level changes during the Holocene, with the Yellow River being the primary source, although there is also some input from local rivers. The changes in sea level during the Holocene and the input of Yellow River material carried by the coastal currents of the Yellow Sea are identified as the main controlling factors for the changes in material sources in the study area since the late Pleistocene, with small and medium-sized rivers also exerting some influence on the material sources. The above mentioned findings not only contribute to a better understanding of the source-sink systems of the Yellow River and adjacent small and medium-sized rivers but also deepen our understanding of the late Quaternary land-sea interactions in the Shandong Peninsula.