The Palaeoclimate Events Between 4.6～24Ka BP, Recorded In A Stalagmite With Ppm Level Uranium Concentration From Jinfo Mountain, Chongqing

The past global change is one of the most important parts in the investigation of the global changes. Exploring how the climate changed in the geological period does benefit to the prediction of the climate change in the future which is necessary because of the serious environment crisis now. China locates in the typical monsoon region and the summer monsoon takes plentiful precipitation to the east of China which is the most populous and developed region of China. The evolvement of summer monsoon must lead to the variation of rainfall and temperature of east China and the deeply affect human lives in this region. Therefore, the researches of monsoon variation have been one of the most important hotpots in climate change. Chongqing locates in the south monsoon region of China, affected by southeast and southwest monsoon, and landform, remarkable"Burn wind effdct",the climate characteristic is muggy in summer, precipitation concentrated, cold and rainy in winter, which affect the develope of economy in Chongqing.Temperature and precipitation are the major factors which influence the fractionation of the oxygen isotope. Temperature and precipitation will change relevantly when altitude rise. That is, temperature will be reduced with the rise of elevation; precipitation will be increased with the rise of altitude. The oxygen isotope of the drop water in the cave with the high altitude also will change because the rise of altitude can change of temperature and precipitation. The elevation of Jinfo Mountain peak is 2251m,when altitude rise, temperature will reduce, the vapor condensed easier in the cloud, precipitation will increase, and theδ18O of drip water in cave will change lower. The result show that among the volume of drip water, temperature in cave and temperature of drip, the volume of drip water and the oxygen isotope of drip water have the highest correlation, the value of R is between 0.988～0.836; temperature in cave and the oxygen isotope of drip water have the higher correlation, the value of R is between 0.513～0.84;the lowest correlation is between temperature of drip water and the oxygen isotope of drip water, the value of R is between 0.466～0.715. The relationship between the oxygen isotope and the volume in the drip water is opposite at the site of YK3# and YK4#, which present "precipitation effect"(that is the relationship between the oxygen isotope and precipitation is negative correlation). The value of oxygen isotope in four sites’drip water is the lightest in winter because the temperature is lowest in winter, and this is "temperature effect"(that is the relationship between the oxygen isotope and temperature is positive correlation)) We can found:23.7～22.8 ka BP, the stalagmite grew fastest with deposit rate is 53.6 mm/ka, but the value of oxygen isotope is increase It is show that the value of oxygen isotope is not light when stalagmite grew fast, and it is like the FR5 recorded.High-resolution oxygen isotope record of YK1 recorded certainly the termination of H2 and D-O2 at 23.57 ka BP and 22.46 ka BP, the beginning time of H1 at 16.63 ka BP. The oxygen isotopic record of YKl is consistent with the stalagmite records of the same latitude region; and earlier than Greenland ice core records, lake sediments in Tibet Plateau, the stalagmite records in low latitude region of India Ocean; later than the stalagmite records in high latitude of South hemisphere.Compared with monsoon region in China, monsoon region in South Asia, the high latitude region in South and North hemisphere, the record of YK1 and the records are not synchronous. Because of the different age point and age error, it is need more and higher-resolution oxygen records to determine the start and stop time of these paleoclimate events, so that to confirm the duration about paleoclimate information in different region.