Characteristics And Environmental Significance Of Quaternary Sporepollen In Laizhou Bay,Bohai Sea

The coastal area of Laizhou Bay in Bohai Sea is flat with typical plain landforms.The area of the plains is broad,the terrain is low and flat,the ups and downs are low,and there are clear-cut changes in landfonns.This is an important part of the North China Plain.Laizhou Bay is a transitional land and sea area that can record global climate change and regional geology with sensitivity.Sediments in this area have a rapid sedimentation rate,and they can preserve the ever-changing land and sea environment and climate change.In this paper,the core samples from three boreholes of GK95,GK111,and GK138 in the coastal area of Laizhou Bay in Bohai Sea were taken as the research object,and the sporopollenium species and combination characteristics of each sample in each borehole were analyzed to explore the sporopollen assemblage.The characteristics of the change and its paleoclimate and paleoenvironmental significance,combined with the dating data and cluster analysis results,the borehole samples were divided into sporopollen assemblages and palaeoclimatic zones,and the evolution of paleoclimate and paleoenvironment since the late Quaternary period was further discussed.A total of 83 sporopollen species were counted in the 3 drilling samples in the study area,totaling 15,655 sporopollens(3707 in GK95,6191 in GK111,and 5757 in GK138).Different stages of climatic evolution are divided by different combinations of sporopollen assemblages.According to the characteristics of sporopollen assemblage in the three boreholes,different sporopollen assemblages were divided from bottom to top.The sporopollen assemblages in the three drilled boreholes all exhibited the characteristics of mutual succession of plant communities with joy and warmth,reflecting the changes in the paleoclimate climate from the Late Pleistocene to the Holocene since the western coast of Laizhou Bay.Since the late Pleistocene,the study area has undergone three times of cool and warm climate changes.The climate change trend is cool and dry-cold and dry-warm and humid-cool and wanner-cold and dry-warm and humid-cold and dry-cool and warm-warm and humid,consistent with global climate change.