【摘要】 从地球层块结构的研究思路出发,运用构造解析的理论和方法,对东亚及西太平洋地区人工地震测深和天然地震面波层析成像进行构造解析,发现岩石圈中下部存在形态各异、大小不等的高速块体,结合地质学、地球化学及其他地球物理学标志的综合研究将其称为幔块构造,高速块体或幔块构造是控制东亚西太平洋岩石圈构造格局和岩石圈表层构造变形最基本条件之一。在系统研究该区岩石圈高速块体或幔块构造三维几何结构基础上,建立起东亚西太平洋岩石圈八种三维几何结构型式:克拉通陆根状结构、高原陆根状结构、造山带楔状结构、碎块状结构、香肠状结构、哑铃状结构、藕节状结构和板状结构,以及岩石圈形成与构造演化四种构造类型:克拉通型岩石圈、增厚型岩石圈、减薄型岩石圈和大洋型岩石圈。文章在详细论述岩石圈各结构构造类基本特征的基础上,认为全球最大的青藏高原具有增厚型岩石圈特性,存在大陆根,并且大陆根正在增厚过程中;地震层析成像显示,研究区存在全球最大的东亚大陆巨型裂谷体系,具有减薄型岩石圈特性,新生代晚期东亚大陆巨型裂谷体系被西太平洋沟弧盆体系叠加与改造。根据岩石圈三维结构型式,探讨了岩石圈形成机制与演化模式,东亚大陆边缘岩石圈大规模伸展拆沉减薄作用以及软流圈和地幔物质上涌加热作用与青藏高原岩石圈大规模俯冲碰撞?入增厚作用是东亚大陆及边缘海晚中生代以来地幔动力学最基本的表现型式,从而形成全球最大的青藏高原和全球最大的东亚大陆巨型裂谷体系。更多还原

【Abstract】 A structural analysis of the tomography of natural seismic surface waves in East Asia and West Pacific region, showed that high-speed blocks of varying shape and size, have been discovered in the lower lithosphere. These are termed mantle blocks, based on their geological, geochemical, and geophysical signatures. These show that the tectonic patterns of the East Asia-West Pacific lithosphere and associated surface deformations are controlled by these high-speed blocks or mantle blocks. Systematic 3D studies of the high-speed blocks in the lithosphere, indicate that eight 3D-geometric tectonic styles (craton-root-shaped, plateau-root-shaped, orogen-wedge-shaped, clastic-massive, sausage-shaped, lotus-root-joint-shaped, dumbbell, and slaty) are described for the first time, together with four types of the lithospheres (cratonic, thickening, thinning, and oceanic). It is further suggested that the Qinghai-Tibet Plateau is characterized by a thickening lithosphere, with the continental root or the lithospheric root involved in the thickening process. According to seismic tomography, the largest rift system in the world is present in the region, which had been overprinted and deformed by the West Pacific trench-arc-basin system during the late Cenozoic. From the 3D geometric models, the ocean-continent-ocean evolutionary patterns of the lithosphere can be deduced. It is concluded that the most basic expressions of the mantle dynamics in East Asia since the Mesozoic can be found in large-scale extension (delamination) and thinning of the lithosphere, within the continental margin, in the upwelling and heating of the asthenosphere, and in the large-sized collision and thickening of the Qinghai-Tibet Plateau.更多还原