| 现今全球构造特征及其动力学解释 |
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| 引用本文： | 马宗晋,高祥林,任金卫.现今全球构造特征及其动力学解释[J].第四纪研究,1992,12(4):293-305. |
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| 作者姓名： | 马宗晋 高祥林 任金卫 |
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| 作者单位： | 国家地震局地质研究所，国家地震局地质研究所，国家地震局地质研究所 |
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| 摘 要： | 构造地质学、大地构造学和全球构造学是三个尺度的构造学研究领域,它们平行交叉而且互有扬弃。全球构造学可分为历史的和现今的两个分支。岩石圈板片和板条构造、板舌构造、洋脊构造以及大陆岩石圈多元组合板的多重滑脱构造和多层剪切构造网络等是现今岩石圈板的基本构造形态。全球级现今岩石圈构造主要表现为三大构造系统:环太平洋深消减带板舌构造系、大洋增生带洋脊构造系和大陆碰撞造山构造系,三者在球坐标系内表现出构造形态、物理场背景和动力学状态等多方面半球级的反对称关系(南/北、0°/180°),各构造系统内部还表现了普遍的东西反对称。论其动力学解释,岩石圈向西和地幔向东相对漂移的定向性显示了地球自转变化的导向作用,决定了经向构造两侧的多级反对称;地震层析探测到的地幔结构显示的热心南偏和质心北偏可能是南北反对称的动力基础;上地幔分层结构及“软层”物质在构造引张条件下形成的热涌有可能解释地表的视对流现象,有助于说明构造变动的跳位和变格以及板条和反对称运动机制。
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| 关 键 词： | 现今全球构造 全球构造系统 构造定向漂移 热心、质心偏移 构造热涌 |
THE FEATURES OF CONTEMPORARY GLOBAL TECTONICS AND ITS DYNAMIC EXPLANATION |
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| Institution: | Institute of Geology, State Seismological Bureau |
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| Abstract: | Structural geology, geotectonics and global tectonics are three research fields in different dimensions with mutual interaction and their own emphases. Global tectonics can be divided into two branches: historical global tectonics and contemporary global tectonics. The basic tectonic forms of the contemporary lithosphere include lithospheric plate and strip, slab structure, oceanic ridge structure, detachment structure with variable dipping angles and nets of shear faulting within continental plates. The following three tectonic systems represent the global-order, contemporary lithospheric structures: the slab structural system of the Circum-Pacific subduction zones, the oceanic ridge structural system of the oceanic growth zones and the orogenic structural system of continental collision. They are characterized by the antisymmetrical relationship of hemisphere-order (north/south, 0°/180° longitude) with regard to the structural form, physical background and dynamic state in the spherical coordinate system. There are also east/west antisymmetrical relationship in each tectonic system. Dynamically, orientation of relatively westward drift of the lithosphere and eastward motion of the mantle may show the directive action of the change of the Earth's rotation, which determines the antisymmetry of multi-orders on the both sides of the longitudinal tectonic zone. The north/south antisymmetry may be attributed to southward deviation of the thermal center and northward deviation of the mass center within the mantle demonstrated by seismic tomography. It is suggested that the structural thermal apwelling caused by the layered mantle and weak material under the tectonic extention might be the mechanism of the lithospheric movement. By using this model we can explain the apparent convection on the surface, jumping displacement and pattern-changing of the tectonic movement as well as the origin of the antisymmetry. |
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