A High-resolution Climate Changes During H1 Event Based On Multi-proxy Stalagmite Records And Cave Monitoring In Western Henan, China

Knowledge in the factors that caused past climatic change is one of the keys to understanding future climate. Multi-proxy and high-resolution records are certainly practical value in predicting climate change in the future. There set stalagmites of Dongshiya Cave as the main research object which located in Luanchuan County, Henan Province, southeastern coast of the loess plateau. Five years monitoring data from Jiguan Cave and oxygen, carbon isotopes and trace elements in stalagmites DSY1205 are presented, and reconstruct the paleo-climate changes from 26.5 to 10.5 ka BP. Furthermore, we find the relationship between the precipitation and cave drops as well as modem sediment, which respond mechanism between cave drops of trace elements and the modern environmental change. Based on the possible driving mechanism of the climate change and control factors of trace elements, we draw a conclusion as follows:(1) We have reconstructed East Asian Monsoon evolutionary series from 26.5 to 10.5 ka BP based on the U/Th age, oxygen isotope and carbon isotope of DSY1205 stalagmites. The maximum value of δ18O in DSY1205 stalagmite records is -5.6%o while minimum value is -10.2%o, these important dates expressly record the H1 cold even, which starting time is 16..0 ka BP. It is noteworthy that the TI positing in 14.7 ka BP of DSY1205 stalagmite is similar to that of other geological records. The climate change from warm to cold in Mysterious Interval, causing by the collapse of the ice sheet, which pouring into North Atlantic Ocean and weaken the AMOC. There is comparability between DSY1205 and ice core record, such as mutability and "W" type gradually mobility during H1;(2) The Mg/Ca, Sr/Ca, Ba/Ca and U/Ca ratio is (10～35)×10-3, (1.2～6)×10-3, (0.1～0.6)× 10-3 and (1.5～8.5)×10-6 respectively. They may respond to the changes of external climatic conditions more accurately, and paleo-climate changes with a good significance. The relationship between Mg/Ca and δ18O in DSY1205 is positive correlation and this situation indicate that the temperature maybe lead the change of DSY1205 Mg/Ca. At the same time, the trends of Sr/Ca, Ba/Ca and U/Ca have showed a high degree of consistency, they also have a good correlation coefficient, this imply that may be controled by the common factors, and absolutely contrary to the changes of δ180 and Mg/Ca, we can infer that temperature and precipitation is not the dominant fators of the change of Sr/Ca, Ba/C and U/C and may affected by surrounding rocke, atmospheric dust and soil;(3) The water of Jiguan Cave can respond the environment outside the cave faithfully. Wet-dry condition of karst system is suggested to be the dominant controller of Mg/Ca ratios in pool water and underground stream. A similar tendency existed in both Sr/Ca and Ba/Ca ratios in water and modern carbonate which implies that they are both influenced by atmospheric dust activities and surface soil, furthermore, Sr/Ca and Ba/Ca are maintain a high value during Luanchuan’s drought in 2013, suggesting they can indicate special weather phenomenon. Mg/Ca ratios of modem carbonate correspond to that of the water respectively. The co-precipitation coefficient constants for Mg/Ca and Sr/Ca between calcite and water has been calculated that Ksr value is 0.02～0.18 and KMg value is 0.01～0.03. KMg has nothing with temperature in short time scales, while positive correlation between KMg and cave temperature is obviously in long time scales.