从克拉通破坏到板块动力模型的研究  

From the Craton destruction to the study of plate dynamical model

作　　者：郝晓光[1] 胡小刚[1] 方剑[1] 刘根友[1] 段鹏硕[1] 冯伟[1] 崔荣花[1] 

机构地区：[1]中国科学院测量与地球物理研究所,大地测量与地球动力学国家重点实验室,武汉430077

出　　处：《地球物理学报》2014年第7期2344-2351,共8页Chinese Journal of Geophysics

基　　金：国家自然科学基金(41374029和41021003)资助

摘　　要：华北克拉通破坏动力机制研究导致了全球动力系统及"板块动力模型"研究.板块运动最有可能的动力是地幔物质流动,但由于地幔物质流动的成因至今尚未查明,所以板块构造学说研究仍处于"运动模型"阶段,而没有进入"动力模型"阶段.如果地幔密度异常是驱动地幔物质流动的成因,那么就有可能基于重力学方法以"板块动力模型"的形式建立地幔密度异常驱动模式;软流圈中可能存在着动力特性不同的区块,地幔密度正异常代表物质盈余、区块内的物质要向区块外移动,地幔密度负异常代表物质亏损、区块外的物质要向区块内移动.本项目采用重力和地震资料相结合研究地球的整体分层,根据重力大地水准面联合地震波速度结构反演求解地幔密度异常,再根据地球正常密度假说和板块运动重力学机制的观点并与现有"板块运动模型"相结合,分析地幔密度异常动力区块,初步建立"基于重力学机制的板块动力模型";为最终建立多学科机制的"全球板块动力模型",迈出重要一步.The research of North China Craton destruction dynamical mechanism has caused lots of studies about global power system and plate dynamical model. The most likely reason for urging the plate motion is the mantle mass flow. However, the things that can urge the mantle mass flow are still unclear enough, so the plate tectonic theory is still in the motion model stage, and not in the dynamic model stage. If the mantle density anomaly is the contributing factor of Earth＇s mantle mass flow , then it is possible to establish the Earth＇s mantle density anomaly drive mode based on the gravity method in the form of plate dynamical model; There may be many blocks with different dynamical properties in the rheosphere, and in which the mantle density positive anomaly represents mass surplus, which signifies the mass would move from inside of the block to outside, then mantle density negative anomaly represents mass loss signifies the material of the block outside could move into the block. This paper studies the Earth＇s overall stratification combined gravity data with Seismic data and the inversion result of the mantle density anomaly can be gained by combining gravity geoid with seismic wave velocity structure. The study also analysis of the mantle density anomaly power blocks based on the normal density theory, plate motion gravity mechanism and the plate motion model. In a word, it is possible to build up the preliminary plate dynamical model based on the gravity mechanism and make an important step for establishing global dynamical model of multi-discipline mechanism, eventually.

关 键 词：重力学机制 地幔正常密度 地幔密度异常 动力区块 板块动力模型 

分 类 号：P541[天文地球—构造地质学]