Paleoclimatic Change During The Last Glaciation Based On Stalagmites From ChongQing JinFu Mts

On the basis of measurement by using thermal ionization mass spectrometry U series method, the ages of the stalagmite from ChongQing JinFo Mountain Liangtianwan Cave ranged 31.90+0.20-15.21 ±0.08ka B.P., which corresponds to MIS2 to the late of MIS3. The influence of East Asian and South-west Monsoon to this area has been discussed during the late period of the Last Glaciation. The oxygen isotopic variability of the stalagmite reveal that the paleo-climate changes can be divided into several stages: in the first stage (32-31.44ka B.P.), corresponding to the late of MIS3 which was warm and dry. The δ ¹⁸O value generally is lower than the average, which implied strong South-west Monsoon. In the second stage (31.44-18.29 ka B.P.), the δ ¹⁸O value higher than the average, the climate is cold and dry. In the third stage (18.29-16.96 ka B.P.), the climate changed obviously and the East Asian and South-west Monsoon were very strong. In the fourth stage (16.96-15.02 ka B.P.), the climate is very cold-dry.Generally speaking in the whole stage (32-15ka B.P.), the δ ¹⁸O value changed from lower to higher, and the temperature changed from higher to lower. Heinrich events 1,2,3 can be recorded in 15.793ka B.P., 24.863 ka B.P., 30.244ka B.P., respectively. As compared to the record of Nanjing Hum Cave and Guizhou Qixing Cave, the δ ¹⁸O changes is very consistent, which coincides with the fluctuation of global paleoclimate change. Meanwhile the obvious differentiation is that the paleoclimate of Chongqing region, even at the middle reaches of Yangtz River, is confined by both the influences of Indian summer monsoon and East Asia summer monsoon.