青藏高原东北部泥炭沉积粒度与元素记录的全新世千年尺度的气候变化

通过对青藏高原东北部共和盆地泥炭沉积的粒度与地球化学元素分析, 重建了区域全新世千年尺度的气候变化过程. 结果显示: 10.0~8.6 cal ka BP区域暖湿程度逐渐增加, 但在8.6~7.1 cal ka BP气候相对寒冷干燥, 7.1~3.8 cal ka BP 暖湿程度总体上为全新世最佳, 但也出现明显的气候波动, 3.8~0.5 cal ka BP气候向冷干方向发展, 0.5 cal ka BP以来气候又逐渐转向暖湿. 这一特征与中国东部季风区的气候变化有很好的一致性. 此外, 区域全新世气候变化过程中存在10次千年尺度的寒冷事件, 并与高原冰芯、 湖泊、 泥炭和风成沉积记录的古气候变化, 甚至与北半球高低纬度的气候变化都具有良好的可比性. 因此, 认为区域全新世气候变化具有"季风模式"与"千年尺度震荡"的双重特点.

Holocene Millennial-Scale Climatic Change Recorded by Grain Size and Chemical Elements of Peat Deposits in Gonghe Basin,Northeastern Tibetan Plateau

Holocene millennial-scale climatic change was reconstructed based on the analyses of grain size and geochemical elements from the peat deposits in Gonghe basin, northeastern Tibetan Plateau. The reconstruction indicates that the regional warm and humid degree gradually increased in 10.0~8.6 cal ka BP, while it was obviously cold and dry from 8.6 cal ka BP to 7.1 cal ka BP. Subsequently, the warm and humid degree reached an optimal state in general between 7.1 cal ka BP and 3.8 cal ka BP, although there were frequently climatic fluctuations. From 3.8 cal ka BP to 0.5 cal ka BP, the climate tended to be cold and dry, and became warm and wet again afterwards. These characteristics are consistent with the climatic variation in the eastern China. In addition, 10 millennial time scale cold events were discovered during the Holocene, which are well comparative with palaeoclimatic records from ice cores, lake, peat and aeolian deposits in the plateau, and climatic fluctuations in the high and low latitudes of the Northern Hemisphere. Therefore, it is believed that the regional climate changes are dual characterized by a "monsoonal model" and a "millennial time scale oscillations".