Abstract:

 On the basis of correlating some significant proxies, such as TOC, δ13C, grainsize and pollen data, from the Napahai lake, Shangrila and the Beihai wetland, Tengchong, and referring the sedimentary rhythm and δ18O record since 60 ka BP from the Bay of Bengal, we found that all of them have been closely affected by the Indian monsoon system. Because of the difference in their latitudinal, longitudinal and sealand situations, however, the climatic records clearly show a differential affinity to the summer monsoon or to the winter one. The most impressive climatic shock over the past 60 ka was a great thermal and wet event that happened roughly from 37 ka BP to 32 ka BP and was evidently manifested within both the Beihais and the Napahais sedimentary sequences. Discordantly, that event cannot be recognized in the marine records. We deduced from the correlation between the continental deposit and marine deposit that the control of the regional climatic event originated from the land side rather than the sea side during the late MIS3. It is likely that an extreme warming up at that phase at the Tibetan Plateau, which resulted in the decline of the Indian winter monsoon and other changes of the atmospheric circulation, was responsible for the event. The geomorphologic configuration played an important role in the monsoonal precipitation as well. 

Key words:  Indian monsoon; Tengchong; Shangrila; MIS3; great thermal and wet event