High Resolution Rapid Climate Change Records of Lacustrine Deposits of Diexi Basin in the Eastern Margin of Qinghai-Tibet Plateau, 40–30 ka BP

Redating with AMS14C dating shows that the deposition time of Diexi ancient barrier lake in the upper reaches of Minjiang River can be traced back to 40.5 ka BP. The grain size proxy index is related to the precipitation indicating the change in climate humidity. In addition, the distinct comparability between the mean grain size curve of Diexi section lacustrine deposits and the δ18O of Greenland ice core and Nanjing Hulu Cave stalagmites shows that the grain size proxy index could respond to global climate change. Thus, the paleoclimate evolution in the study area could be divided into three stages: 40.5–33.4 ka BP, cold and dry; 33.4–31.7 ka BP, warm and humid; 31.7–31.1 ka BP, still warm and humid, but not as much as prestage. The differences between these curves could be interpreted by the variation of insolation change in different locations and the influence of monsoon.