A Paleoclimate Environment Study on the Main Characteristics of Sedimentary Cycles in Stalagmite

We summarize the characteristics of sedimentary cycles,cycle interface types of some stalagmites and related significances in climatic,environmental and geological sciences.Before that,the components and structures of some typical large stalagmite in southern China were studied.Also 210 isotopic samples of δ¹⁸C,δ¹⁸O,20 samples for Useries dating in D10 and some related trace elements were analyzed comparatively.According to the colors reflected by different impurities in carbonate,the lamina features and isotopic components of stalagmite in D10,three cycling features which are accordant parallel,unaccordant parallel and unaccordant unparallel can be divided.19 sediment arycycles can be identified.The average δ¹³C,δ¹⁸O value -3.91‰PDB and -6.97‰PDB respectively represent the threshold values which indicate the evolution of cold and warm climate.Consequently,if the isotopic value is higher than the threshold value,it means the climate is in favor of cold conditions.According to the isotopic and cycle characteristics of the sedimentary,it is considered preliminarily that the 19 cycles deposited during the years from 352 930 to 99 410 in Libo area indicate a relatively complete process of the climate evolution in the fifth Ice Age of the Quaternary Ice Age series in China.The 50 000 years which is calculated from cycle 10 to cycle 15 is surmised as a continuous freezing glacial maximum.The cycle 1 and cycle 16 represents probably interg lacial period which was relative warmer.Furthermore,there also existed 50 000 or 100 000 years scale climatic cycle during the period.