The Sedimentary Records From The Bei Hai Wetland, Tengchong And Its Relation To The South Asian Summer Monsoon

Tengchong located at the western Gaoligong Mountain in Yunnan Province, is influenced by southwest monsoon in climatic variation; therefore, it becomes the ideal region for southwest monsoon study. Furthermore, a 32.53m long core from Beihai in Tengchong could record the climatic variation for 150kaBP entirely. This paper has reconstructed the climatic evolution for 150ka through the climatic proxy such as grain size, TOC,δ13C and natural thermoluminescence, and has compared it with the climatic evolutions in the Bay of Bengal, Zhongdian, Heqing and Qinghai-Tibet Plateau. Additionally, this project enriches the materials on southwest monsoon study and fills the vacancy in climatic study for the western of the Gaoligong Mountain. Especially, it provides the land materials for the land-sea comparison in the north Indian Ocean.Grain size can indicate the water level variation and the moisture evolution, and reflect the hydrodynamic situation. Moreover, it is well correlated with the other climatic proxy data. However, TOC is related with continental organic content. In the Beihai area, high TOC reflects the warm period with high production, whereas the contrary. The carbon isotope is related with redox situation and lake production. That highδ13C indicates warm period with abundant plants, whereas the contrary. Finally, the thermoluminescent values of sediments could also reflect the climatic variation as high value indicates cold period corresponded, whereas the contrary.For special water-thermal configuration, the climate in Tengchong area is characterized by dry warm to wet cold. During the 150Ka, the climate area has experienced the process such as two glacial periods, final interglacial period, final glacial period and postglacial period. Furthermore, the climatic variation after the final interglacial period becomes the key subject investigated. Additionally, the climatic variation after the final interglacial period underwent five stages two warm stages and three cold stages. However, there were also climatic fluctuates in the five stages. Moreover, the records about Heinrich event happened in the final glacial period could be found in Beihai.The climatic variation in Tengchong is mainly influenced by the climate in the Bay of Bengal. However, it is different from sea in climatic variation for the difference between land and sea. The climate in Tengchong is similar to it in Zhongdian, Heqing etc., but there are differences in water level of lake. The reason is that the former is influenced by the South Asia summer monsoon, but the later by southwest monsoon, northeast monsoon etc. Furthermore, Based on the comparison with the Guliya ice core, it can be disclosed that the climate in Tengchong is affected not only by South Asia summer monsoon, but also the climate in Qinghai-Tibet Plateau.