As Early Holocene The Liaoning Warm Cave, Laminae And Climate Events

Based on 13230Th ages,2072 annual thickness data,1583 isotopic data and massive amount of gray level data from 3 stalagmites from Nuanhe Cave in Northeast China, a Multi-proxy (δ18O,813C, gray level, etc) integrated authentication was used to confirm the climatic significance of annual thickness. Meanwhile, the appearance of "8.2 ka climate event" in this sequence has been discussed also.As theδ18O data from cave-original stalagmites in Chinese Monsoon region may indicate the variation of precipitation, the similarity of two curves ofδ18O and annual thickness should indicate that the latter may indicates the variation of precipitation during the summer monsoon. It was confirmed by the analogy between annual thickness andδ13C. Power spectrum analysis on two sequences of annual thickness and gray level revealed the existence of ENSO events with different frequencies during the early Holocene, this was also confirmed by the cross spectrum analysis and EMD results.According to the mechanism research ofδ13C variation, and the research of variation of dark material input (gray level) based on dripping water observation in modern caves, the covariance between gray level andδ13C in these stalagmites suggested that they could be used as two indicators of the variations of cave effective humidity and monsoon rainfall.Climate in early Holocene was not stable, several decades to hundred-year scale of climate events were found in the period, such as the cold event in 8.2 ka BP, which was named "8.2 ka climate event". Based on the ICP-MS U-series dating and annual layer counting results, we established a chronological framework for theδ18O profile of the Nuanhe Cave stalagmite, in which we didn't find a significant appearance of "8.2 ka climate event". Combination of dendrological△14C result and North Atlantic sediment records, suggest that the "8.2 ka climate event" was induced by both of solar activity and Therrnohaline Circulation (THC), then speared to other regions through dtmospheric and oceanic circulations. But the existences of different kinds of feedback mechanisms may have reduced the signal, and caused the non-obvious of this event in the records of stalagmites from this region.