EARLY HOLOCENE LAMINATED STALAGMITE RECORDS FROM NUANHE CAVE,BENXI,CHINA

A nearly 1 500-year time series inferred from annual layer thickness, gray level, and oxygen isotope variation during (8 630~7 050)±50 aBP has been established, with the support of three ²³⁰Th ages and annual layer-counting results of a stalagmite (No.NH6) from Nuanhe Cave in Benxi City of Liaoning. The similarity in microstructures of annual layer among NH6, Shihua Cave from Beijing and Glacial phase of Hulu Cave from Nanjing, and the diagnostic annual-seasonal cycling interfaces which is typical in northern China, suggest clearly that the annual growth of stalagmites is dominated by climatic factors in the monsoon zone of east China. The layer thickness and gray level vary synchronously in decadal-centennial scale (correlation coefficient r=0.56, n=1 580), indicates the inner relationship between incoming material (like organic substance and so on) and dropping-water saturation in the caves when precipitation changes dramatically in different seasons. Their power spectrum analysis show periodic changes of 2~11 years, which is coincide with modern monsoon precipitation change. The different variation history between annual growth rate and oxygen isotope, may be caused by the complicated mechanism when cave environment responsed to large scale monsoon climate.