The Influence of Paleoclimate Change on the Identification of Paleosedimentary Environment in Coastal Areas

Paleoclimate change is closely related to paleosedimentary environment, so the impact of paleoclimate cold and warm change on the identification of paleosedimentary environment in coastal areas is studied. Taking the coastal area of Zhejiang Province as the research area, the BZK1 borehole was used to collect soil samples from the coastal area of Zhejiang Province, and the pollen samples after treatment were identified by optical microscope. The foraminifera, ostracods and grain size were identified, and the paleosedimentary environment was analyzed by making maps. The results show that the coastal strata of Zhejiang Province can be divided into four stages according to the changes of sporopollen assemblage, foraminifera and ostracoda species distribution, abundance and diversity. Since the late Pleistocene, the general trend of change in the study area is warm, humid, warm, humid, warm and humid, and gradually turned to cold and dry, and this climate fluctuation is consistent with the change of sea level rise and fall. Based on the general trend of paleoclimate change in the study area, the paleosedimentary environment in the study area is further analyzed through the characteristics of grain size parameters and grain size composition. According to the depth, the sediment is divided into seven stages. Since the late Pleistocene, the sediment is mainly silty sand. The process of hydrodynamic condition change in the deposition process is: medium energy--medium low energy--medium energy--medium low energy--medium energy. The change of sedimentary facies is: shore--shallow lake--flood plain river--shallow lake--beach--bar lake--marsh flood plain--shallow sea--swamp. Keywords Paleoclimate; Cold warm transformation; Coastal area; Paleodeposit; Environment.