Holocene Climate Change And Neotectonic Movement In Jinling River Basin,Shaanxi Province

Jinling River Basin is located in the southwest of Loess Plateau,which is a sensitive region of monsoon evolution.Affected by the east Asian monsoon climate,it has a unique response mode to global climate change.The Holocene Loess-paleosol sequence on the Loess Plateau of the Jinling River Basin has recorded well the climate and environment evolution of the Holocene over the past 10,000 years.The Holocene is the latest stage of earth's development and is closely related to human activities.In the process of studying climate evolution,especially Holocene climate evolution is the most important.Studying the evolution of climate in Holocene is of great significance for understanding the formation of modern environment,predicting the future evolution of climate,finally discussing the driving mechanism of climate evolution and summing up the law of climate evolution.The Holocene Loess-paleosol profile of Zhoujiazhuang on the first terrace of Jinling River in Baoji of Guanzhong Area is selected for this paper,based on a large number of field geological investigations.The research profile is stable in stratum,continuous and complete,and well preserved,which truly reflects the climate change and the relationship with the neotectonic movement since the Holocene in the Jinling River Basin.Based on the systematic analysis of the Loess-paleosol sequence in Zhoujiazhuang section of Jinling River Basin,the common paleoclimate proxy index,such as particle size and magnetic susceptibility,is measured and the sedimentary sequence age is obtained by photoluminescence.By comparing the research curves of other scholars in adjacent areas,the evolution law of climate environment in Jinling River Basin since Holocene is obtained,and the response between the evolution of climate environment and neotectonic movement in Jinling River Basin is discussed finally.The main conclusions can be drawn as follows:?1?Through analyzing frequency curve and cumulative curve of particle size,average particle size Mz,standard deviation?₁,skewness SK₁,kurtosis K_G,particle size C-M diagram of Zhoujiazhuang Loess-paleosol profile,it is shown that the loess samples have excellent sorting ability,uniform particle size distribution,simple sedimentary environment and stable dynamic conditions,belonging to the aeolian sedimentary loess.?2?Based on the analysis of the magnetic susceptibility,particle size and the photoluminescence lateral years of sediments and the synthesis of previous research,the evolution of the climate environment in the region since Holocene is finally obtained.It can be divided into the following stages:?1?11,500–8500ab.p.,the warming stage;?2?8500–6000ab.p.,the warming stage of the Holocene Megathermal;?3?6000–3100ab.p.,the cooling stage of the Holocene Megathermal;?4?3100–1500aB.P.,the Holocene climate cooling stage;?5?1500–now,the Holocene climate cold stage,but the climate has a warming trend,which may be the impact of later human activities.?3?The study on the evolution of climate in the Jinling River Basin since the Holocene and on the Tibet Plateau shows that the uplift of Tibetan Plateau provides a source of power for the evolution of climate in the Jinling River Basin,and changes its climate circulation pattern,which is the main driving force for the evolution of the Holocene climate and environment of this region.climate.