Holocene Climatic And Environmental Records In The Gaoling Section Of The Lower Reaches Of Weihe River

The Holocene is a period of development of modern mankind and its social development.Regional environmental changes have a profound impact on human development.The the Yellow River river basin is the birthplace of Chinese civilization.The paper selects the Weihe loess section of Weihe first terrace at Jinghe River intersection to carry out paleoclimatic environmental records.The section is composed of Ma Lan loess Holocene black earth and Holocene loess.This study has important scientific significance to reveal the climate change,paleo flood and the influence of ancient civilization in Weihe basin since Holocene.On the basis of the analysis of the grain size,magnetic susceptibility and carbon isotopes of the Gaoling section,the climatic and environmental indicators were established,and the profile time scale was established in the light release light year.According to grain size,magnetic susceptibility,carbon isotope index and time scale,the Holocene climatic fluctuation recorded in Gaoling section is divided into 5 stages:?1?5.6⁴.4m?22 ka-11 ka?is the upper layer of Ma Lan loess?L₁?,and the climatic dry and cold period of late last glacial period is recorded.?2?the 4.4³.2m?11 ka-4 ka?Holocene paleosol S₀² recorded the gradual enhancement of the summer monsoon and the gradual weakening of the winter wind,and the late last glacial climate gradually entered the Holocene suitable period.The grain size and magnetic susceptibility index fluctuated during the period of the last glacial period,indicating that the climate was unstable in the suitable period of the Holocene;?4?3.2¹.7m?4 ka-1.9 ka?the strata are the loess layer?L₀²?and the weak palaeosol layer?S₀¹?,which sandwiched by the flood stagnant water deposit?SWD?at 2.0².35 m,and the horizontal bedding silt layer.The upper and lower strata are respectively the loess layer and the weak paleosol layer,and recorded a flood event of about 2 ka in the late Holocene arid climate,and the weak palaeo soil.The soil layer reflects the climate fluctuation in the optimum period of the Holocene in the Holocene of 4 ka.?4?1.7¹.0m?1.9 ka-1.2 ka?is a late Holocene paleosol layer?S?,which records a relatively moist climate and corresponds to the Sui and Tang Dynasties.?5?0.2-1.0m?1.2 ka so far?is the loess layer of the late Holocene L₀¹,the overall magnetic rate is lower than the paleosol layer,indicating that it is more suitable.It is suitable for the climatic characteristics of drought.The record of flood events occurred around 2 ka in the late Yangshao culture of the Yangshao culture,Shaanxi,Gaoling County,Shaanxi,Gaoling County,Shaanxi Province,where the ancient flood events were recorded with the time of the Weihe terrace GL section.After the flood,the ancient people of Yangguan site were clustered.When the fall is completely abandoned,it is possible that the Weihe flood will affect the ancient human settlements of Yang Guan Zhai at the intersection of Jingwei and Weiwei,and may cause a disaster.This ancient flood event has important scientific significance for the study of the evolution of human civilization in the Weihe River Basin and the middle reaches of the Yellow River.At the same time,the process of the Holocene climate change recorded by the GL section is well corresponding to the other Holocene loess paleosol research sections in the Weihe basin,which is of certain significance to the study of the relationship between climate change and the evolution of ancient human civilization.