DECADAL-SCALE CLIMATE CHANGE OF EAST ASIAN MONSOON DURING THE LAST GLACIAL MAXIMUM FROM STALAGMITE RECORD

A 7-8 year resolution oxygen isotope record, based on 9 ²³⁰Th data and 430δ¹⁸O data of three stalagmites, provides a history of the Asian Monsoon during a time interval from 18.4 to 14.4 kaBP. The fact that the fairly good replication of δ¹⁸O signal in the multidecadal-scale at periods when the stalagmites from Qingtian Cave and Hulu Cave grew contemporaneously (17.5-16 kaBP and 18.4-17.5 kaBP) indicates that the δ¹⁸O signal from these two localities recorded climatic changes and that changes in the mon-soon were similar over a large area of China. There are two remarkable weak summer monsoon events at 17.7 kaBP and -16.1 kaBP in our stalagmite δ¹⁸O records which show a dramatic positive shift of 2‰ in δ¹⁸O, coincident within error with Hlb and Hla in the North Atlantic. There may have been a strong monsoon precipitation event in the interval from 18.3 to 17.7 kaBP, equivalent to half of the average level of Bølling Warming. This strong monsoon precipitation event may be ascribed to response to changes of the Atlantic Meridional Overturning Circulation. Six wet-dry fluctuations with a pace of 80-90 years that is similar to Gleissberg cycle of the solar activity are superimposed on this event. Our data show that the monsoon variability of these frequencies may have resulted from changes of solar activity.