中国第四纪冰期数值年表初步划分

NUMERICAL PERIODS OF QUATERNARY GLACIATIONS IN CHINA

20世纪70年代以前,我国第四纪冰川冰期主要是根据第四纪冰川遗迹的侵蚀-沉积地貌特征和沉积物的物理化学风化程度的差异划分的相对年代;80～90年代开始有放射性碳和地衣法的测年;90年代以后,采用热释光和电子自旋共振技术测年,获得了我国第四纪冰川的一些数值年代,划分了5次冰期,其时代初步定为:小冰期Ⅲ(1871±20A.D.),小冰期Ⅱ(1777±20A.D.),小冰期Ⅰ(1528±20A.D.);新冰期Ⅲ(1550±70aB.P.,1580±60aB.P.),新冰期Ⅱ(2.8～2.5kaB.P.),新冰期Ⅰ(3.1kaB.P.);末次冰期Ⅳ(YD)(11.5～10.4kaB.P.),末次冰期Ⅲ(24～16kaB.P.),末次冰期Ⅱ(56～40kaB.P.),末次冰期Ⅰ(73～72kaB.P.);倒数第二冰期(相当于MIS6～10),Ⅲ阶段(154～136kaB.P.),Ⅱ阶段(277～266kaB.P.),Ⅰ阶段(333～316kaB.P.);倒数第三冰期(相当于MIS12～16),Ⅱ阶段(520～460kaB.P.),Ⅰ阶段(710～593kaB.P.)。未来的研究趋势是采用宇宙成因核素暴露年代方法和光释光技术在更大的空间尺度上对冰川地貌精细定年,分析第四纪冰川发育的空间差异和异时性机制。

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.）, Stage Ⅱ（1777±20A. D.）, Stage Ⅰ（1528±20A. D.） ; Neoglaciation, Stage Ⅲ（1550±70aB. P. , 1580±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.）, Stage Ⅰ（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.