CLIMATIC RECORDS FROM ANNUAL LAYERS AND STABLE ISOTOPES OF A STALAGMITE IN BEIJING OVER THE LAST 2300 YEARS

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CLIMATIC RECORDS FROM ANNUAL LAYERS AND STABLE ISOTOPES OF A STALAGMITE IN BEIJING OVER THE LAST 2300 YEARS

In this paper the authors report a preliminary study on a Holocene stalagmite from Shihua Cave in Southwest Beijing.The result shows that the thickness of annual growth layers which is defined by annual deposit hiatuses preserve changes with precipitation. In light with the thickness of annual layers the authors reconstruct the climatic variation history of the last 2300 years in Beijing area.The climatic patterns seems to reappear irregularly on millennium to decade scales in the last 1000 years. The stable isotopic sequence interprets that the climate and environment in Beijing could be separated into two stages in the late Holocene: the monsoon was strong and the environment was wet in the former stage and in the latter stage the monsoon was weak and the environment was dry. The annual layers and oxygen isotope could be taken as natural signals and carbon isotope as a comprehensive signal containing the natural information and the information of anthropogenic activity.