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地球化学元素比值的变化不仅可以指示气候变化和环境特征,也可以揭示气候异常和突变性气候事件。本文通过对沂沭河流域沭埠岭剖面沉积物淋溶系数、残积系数、CaO/MgO、硅铝率、硅铝铁率等气候代用指标的分析,发现研究区7 470~2550 a BP期间的气候变化经历了五个阶段:(1)7 472~6 043 a BP,气候趋向温暖湿润;(2)6 043~4 801 a BP,稳定的暖湿时期;(3)4 801~3 986 a BP,气候向冷干转变;(4)3 986~3 512 a BP,不稳定时期;(5)3 512~2 552 a BP,气候不稳定的波动时期。
Changes in geochemical element ratios can indicate not only climate change and environmental characteristics but also climate anomalies and catastrophic climate events. Based on the analysis of the climatic proxy indexes of sediment leaching coefficient, residual coefficient, CaO / MgO, Si-Al ratio and Si-Fe-Al ratio in Shubuling section of Yishu River Basin, it is found that during the period of 7 470 ~ 2550 BP in the study area Climate change has experienced five stages: (1) 7 472 ~ 6 043 a BP, the climate is warm and humid; (2) 6 043 ~ 4 801 a BP, stable warm and humid period; (3) 4 801 ~ 3 986 a BP, climate changes to dry and cold; (4) 3 986 ~ 3 512 a BP, unstable period; (5) 3 512 ~ 2 552 a BP, unstable period of climate fluctuations.