NUMERICAL PERIODS OF QUATERNARY GLACIATIONS IN CHINA
Yi Chaolu① Cui Zhijiu② Xiong Heigang③(①Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085;②College of Environmental Sciences, Peking University, Beijing 100871;③College of Resources & Environment Science, Xinjiang University, rümqi 830054)
Quaternary glaiciation periods were divided by relative dating methods in China before the 1970s. Researchers used the features of glacial erosional and sedimentary landforms as well as the differences of the glacial tills in chemical and physical weathering to determine the ages of Quaternary glaciations. Radiocarbon 14 and lichenometric chronology during the 1980～90s, and thermo luminescence (TL) and electronic spinning resonance (ESR) after the 1990s last century were used to date the glacial tills. Based on the dating results, five Quaternary glaciation stages are determined primarily as follows: Little Ice Age, Stage Ⅲ(1871±20A.D.), StageⅡ(1777±20A.D.), StageⅠ(1528±20A.D.);Neoglaciation, Stage Ⅲ(1 550±70aB.P., 1 580±60aB.P.), Stage Ⅱ (2.8~2.5kaB.P.), Stage Ⅰ(3.1kaB.P.);Last Glaciation, Stage Ⅳ(YD)(11.5~10.4kaB.P.), Stage Ⅲ (24~16kaB.P.), Stage Ⅱ (56~40kaB.P.), StageⅠ(73~72kaB.P.);Penultimate Glaciation (equivalent to MIS 6~10), Stage Ⅲ (154~136kaB.P.), Stage Ⅱ (277~266kaB.P.), Stage Ⅰ(333~316kaB.P.);The Third Glaciation counting backwards (equivalent to MIS 12~16),Stage Ⅱ (520~460kaB.P.), Stage Ⅰ(710～593kaB.P.). It is a trend to use cosmogenic radionuclides and optical stimulated luminescence to date glacial moraines precisely in large scale and analyze the differences of Quaternary glaciations in space and timing and their mechanisms.