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HYH-09 International perspectives on karst aquifers and water resources
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The relationship between stalagmite growth rate and carbon and oxygen isotope records from stalagmite D4 and its interpretation
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Xiaoyan Zhu , Karst Dynamics Key Laboratory, Institute of Karst Geology, CAGS (China)
Meiliang Zhang , Karst Dynamics Key Laboratory, Institute of Karst Geology, CAGS (China)
Hai Cheng, Department ofGeology and Geophysics, University of Minnesota (United States)
Yushi Lin , Karst Dynamics Key Laboratory, Institute of Karst Geology, CAGS (China)
Jiaming Qin, Karst Dynamics Key Laboratory, Institute of Karst Geology, CAGS (China)
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Carbon and oxygen isotope records from stalagmite D4 in Dongge cave, China show different relations with its growth rate in the past 15,600 years, suggesting that stalagmites grow under the double controls of ecosystem (vegetation) and climate. The δ13C records of stalagmite D4 show different relations with its δ18O records, suggesting that vegetation could play a buffering against climate changes in some degree and the buffering depends on vegetation characteristic. The δ13C values of stalagmite tend to be heavier suggesting that vegetation is weakening and in some degree turn to different weaker vegetation tapes, and vice versa. Vegetation plays a role of In 15600∼9000a B.P., cold-cool climate made vegetation re-establishing slow, and stalagmite grew at a low rate. During 9000∼3500a B.P. climate became warm and humid and vegetation developed to a good condition, which favored a much higher stalagmite growth rate than before. Since 3500a B.P., vegetation adjusted itself following a few climate changes, and the stalagmite grew variedly with vegetation. Vegetation adapts itself to climate changes to minimize or magnify the effects, and the stalagmite responds to climate through the influence of vegetation. Different kinds of vegetation respond to climate shifts in different ways. Where there is abundant vegetation, there is no response to weak shifts in climate; abrupt climate changes are initially resisted, then the vegetation responds belatedly. Poor vegetation transfers climate shifts with little modification to be preserved in stalagmites.
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