Paleoclimate Change Since Late Pleistocene In Huailai Basin From Hebei Province

Since the late Pleistocene,the global climate has experienced extremely frequent dry-wet and cold-warm alternations.Huailai basin,located in the northwest of hebei province,is very sensitive to climate change since the late Pleistocene.In this paper,the Wanyaocun profile of Huailai Basin is selected as the research area.The paleoclimate evolution process since late Pleistocene was then reconstructed by combining the environmental substitution indexes such as particle size,and the regional comparison was made to preliminarily discuss the causes of climate change.The following conclusions can be drawn:(1)According to the characteristics of the strata in the section and combined with the previous research results in this area,the stratigraphic sedimentary characteristics of the study area were analyzed,and it was found that the lithology changed from coarse to fine to coarse again.The sedimentary environment shows the transformation of fluvial facies-lacustrine facies-fluvial facies.(2)The climate evolution since the late Pleistocene in the study area was divided into four stages according to the environmental substitution indexes in the section of Wanyaocun profile : In the middle of the late Pleistocene,the climate was mild and humid.The climate was warm and humid in the middle and late late Pleistocene.In the late of the Late Pleistocene,the climate was cold and dry;During the Holocene,the climate was mild and slightly dry.Which showed the fluctuation of temperature from warm-moist to hot-moist and then to cold-dry climatic variations.(3)Regional correlation analysis showed that the paleoclimate evolution of the basin offered similarity to the global climate change and climate events such as YD event,B?lling warm period,8.2 ka cooling event were more obvious.However,in comparison with the central and southern Hebei Plain,Huailai Basin entered the last ice age earlier and lasted longer,and the climate was drier in the Holocene.This trait should be attributed to the higher latitude and elevation of the sampling site in the study area.