论文部分内容阅读
The δ18O records of ostracode shells in sediments of core QH-2000 from Qinghai Lake can be used as a better proxy to reflect monsoon changes. Low monsoon precipitation between 17.5 and 11 cal. Ka BP is indicated by positive δ18O values averaging 2.37‰. A fast shift in δ18O from positive at 11 cal. Ka BP to negative at 10 cal. Ka BP indicates sharp increase of monsoon precipitation. An interval of generally high monsoon precipitation is observed between 10 and 6 cal. Ka BP with δ18O values averaging -2.15‰. Decrease of monsoon precipitation between 6 and 2.5 cal. Ka BP is indicated by positive δ18O values. δ18O keeps positive values averaging 3.0‰ between 2.5 and 0 cal. Ka BP suggesting low high monsoon precipitation. The climatic changes indicated by δ18O records of ostracode shells in sediments of core QH-2000 from Qinghai Lake and our broader regional comparison show that the climate in Qinghai Lake since the late Glacial is probably controlled by southwest monsoon other than southeast monsoon.