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构造气候旋回的理论要点是构造作用驱动气候变化,因而不同于Milankovitch冰期气候旋回,但两者又都是受地球轨道要素控制的。本文主要根据青藏高原和黄土高原的晚新生代地质记录,以磁性地层为时间标尺,以黄道倾斜(ε)最大变幅位置为模式年龄,划分最近8Ma的准1.2Ma周期构造气候旋回的主旋回层,即MTC7、MTC6、MTC5、MTC4、MTC3、MTC2、MTC1、MTC0,它们的界线年龄分别为7.3、6.1、4.9、3.7、2.5、1.3和0.2MaBP。在此基础上,分析了青藏高原构造隆升和黄土高原风尘沉积各自显示的准1.2Ma周期的演变特征,表明它们之间具有构造驱动气候的因果关系。文中还探讨了最近7.3MaBP的古环境变迁,获得了有关晚新生代东亚季风形成演变和环境分异是在轨道气候旋回背景下受构造气候旋回控制的新认识。
The theoretical point of tectonic climatic cycles is that tectonic action drives climate change and thus differs from Milankovitch glacial climatic cycles, but both are controlled by the orbital elements. Based on the Late Cenozoic geological records of the Qinghai-Xizang Plateau and the Loess Plateau, the authors use the magnetic stratum as a time scale and take the ecliptic (ε) maximum luffing position as the model age to establish the quasi-1.2Ma cycle of the most recent 8Ma. Cyclization layers, namely MTC7, MTC6, MTC5, MTC4, MTC3, MTC2, MTC1, MTC0, have a boundary age of 7.3, 6.1, 4.9, 3.7, 2.5, 1.3 and 0.2MaBP. On this basis, the evolvement characteristics of the quasi-1.2Ma cycles displayed by the tectonic uplift of the Qinghai-Tibet Plateau and the dust deposits in the Loess Plateau are analyzed, showing that they have causal relationship with tectonic driving climate. In the paper, the recent paleo-environmental changes of 7.3MaBP are also discussed, and some new understandings about the formation and evolution of the East Asian monsoon in the late Cenozoic and the environmental differentiation are controlled by tectonic cycles under the background of orbital climatic cycles.