Characteristics and chronology of loess along the coast of the Bohai Sea, China

Abstract The Bohai coast loess deposits hold significant value for understanding climate and sea-level changes. This review analyzes stratigraphic and chronological data and arrives at three main conclusions. (1) Liaodong Peninsula loess is 10–25 m thick, primarily distributed in nearshore bay areas with NW slope aspect. In the Shandong Peninsula coastal zone, thickness measures 5–15 m, showing NW aspect in Penglai but southward in Yantai. Thickness variations correlate with sedimentation rates and underlying terrain gradient, while slope aspects indicate sediment sources and topographic controls. (2) Loess along the Bohai coast rapidly accumulated during 22–31 ka and 61–68 ka, lasting longer (18–70 ka) in the Shandong Peninsula coastal area and the Miaodao Archipelago due to Yellow River input. Around 150 ka, regional differences emerged (e.g., loess in the Shandong Peninsula coastal area and the Miaodao Archipelago experienced rapid deposition at 148–175 ka). Liaodong Peninsula ages before 125 ka are underestimated, likely due to inaccurate quartz dating. (3) The paleosols mainly developed during 4–15 ka, 75–85 ka, 90–100 ka, and 125–130 ka. The Shandong Peninsula coastal area and Miaodao Archipelago show more layers and greater thickness of paleosols compared with the Liaodong Peninsula, which is related to the differences in hydroclimate conditions and loess grain size.