摘要
热能聚散交替、地幔蠕动是构造–岩浆活化理论创建初期提出的动力学机制假说。深部地质研究开拓了岩浆活化构造动力学研究的深度。许多地球化学家和地球物理学家对中国中新生代构造演化的研究,给热能聚散交替、地幔蠕动假说提供了科学证据。近20年来对华北克拉通破坏的动力机制研究,促进了构造–岩浆活化动力学机制研究的深入。构造–岩浆活化的动力学过程如同克拉通破坏一样,是一个复杂的地质过程:从稳定的地台区到地台活化区,其动力体制的转化既具有渐变到突变的特点,又是呈阶段性发展的;既有时间上的阶段性又有空间上的迁移性。在由地台阶段向地台活化阶段转化的过程中,上地幔化学结构由亏损状态向富集状态转化,地幔交代作用是导致地台活化的先驱事件。中国东部大陆岩石圈减薄的事实证明,控制岩石圈破坏过程中物质交换与能量转换的关键部位发生在壳幔过渡带。通过大陆岩石圈中孔隙波的产生和传播,地幔物质和热量通过壳–幔过渡带传输到地壳中去,导致东部大陆地壳的构造–岩浆活化。由于孔隙波造成物质和热流的向上运动,导致大陆岩石圈热结构发生调整。为了探讨这一机制所导致的上涌流对大陆岩石圈中热结构模式的可能影响,在岩石圈尺度范围内通过数学运算推导出了与上涌流有关的传热问题的理论解。由理论和数值分析获得不同上涌流条件下的大陆岩石圈不同热结构模式与依据地球物理、地质资料获得的大陆岩石圈热结构模式十分吻合。大陆岩石圈内传质传热模型与热能聚集、地幔蠕动是一致的。华北克拉通破坏(地台活化)的数值模拟实验与地质事实证明这是一种主动活化,反映了地幔传导热流与上涌流速率在华北克拉通岩石圈破坏过程中起着的重要作用,而华北克拉通边缘的板块活动是克拉通破坏的导火线。
Energy coacervation-diffusion alternation and mantle creep as the dynamic mechanisms were the basis of the tectonic magmatic activation theory when it was initially proposed. Later on, the detailed geological researches developed the tectonic dynamics of magma activation. Geochemists and geophysicists provided the scientific evidence for the heat energy coacervation-diffusion alternation, mantle creeping hypothesis through studies of the Meso-Cenozoic tectonic evolution in China. In the last two decades, the study on the dynamic mechanism of the North China Craton destruction further developed dynamic mechanism further in-depth study of magmatic activation's dynamic mechanism. The dynamics process of tectonic magmatic activation as craton destruction complicated geological process: From The transition of a stable platform region to the activation of platform region, transformeds the power system, which was accompanied by the catastrophic characteristics and periodic development. It has both characteristics, stages in time and migration in space. The chemical texture of the upper mantle changed from depleted to enriched state during the evolution from the platform to activated platform stage. The timing dating results of isotopic systematic reveals that mantle metasomatism was a precursory event resulting in platform activation. We thus proposed a tentative initial model of for platform activation mechanism. The lithosphere thinning in the eastern part of continental China has proved that the key part controlling the material exchange and the energy conversion usually occurred in the crust mantle transitional zone. By using the concept of a nonlinear porosity wave in a deformation porous medium, a conceptual model of the formation of the crust mantle transitional zone can be set up. By the generation and propagation of the porosity-wave in continental lithosphere,the mantle material and heat could be transferred into the crust through the crust-mantle transition zone, caused the tectonic magmatic activated in the eastern continental crust and the adjustment of the thermal structure of the continental lithosphere in China. To explore the affect caused by upwelling heat flow, in the lithosphere scale, range the theoretical solution of the flow and heat transfer is discussed mathematically. Good agreement between the thermal structure types obtained from the generation and propagation of porosity waves is one of the potential mechanisms for material and energy exchange between the continental lithospheric mantle and the crust, which may affect the lithospheric thermal structures significantly. In continental lithosphere mass and heat transfer model is consistent with the heat accumulation and the mantle creep. The simulation experiment and geological facts of the destroy of the North China Craton(activation of platform) proved that this was a kind of initiative activation, reflecting the mantle conduction heat flow and upwelling flow play an important role in the failure process in the North China Craton lithosphere. Therefore, the plate activity in the edges of the North China Craton is the direct cause of the craton destruction.