地幔内板片俯冲运动模式及其大地构造意义——俯冲的屏障与穿越机制

Subduction patterns within mantle and its tectonic significance——Subduction barrier and crossing mechanism

地震层析成像揭示了地幔内存在俯冲板片的重要证据,它们涉及多种几何形态和运动方式,地幔过渡带为其下沉的重要屏障,俯冲板片在这里发生停滞、变形和岩石圈物质积累。板片在个别地区可以俯冲到地核—地幔边界,堆积形成板块墓地,造成D″层物质组成和热学的不均一性。高温高压实验以及流变学计算模拟,对地幔组成及其物性提供了新的制约,板片俯冲地幔过程中,涉及矿物相变、黏度、密度、力学强度等因素的制约,地幔过渡带为俯冲重要屏障和相变界面。围绕板片俯冲的研究,提出地幔整体对流的新模式,板块墓地与超级地幔柱具有成因联系,成为全球地幔对流的重要环节,有待深入研究。板片俯冲是浅表板块构造与深部超级地幔柱的联系纽带和重要驱动力。

Seismic tomography reveals important evidences of subduction slab within the mantle, which involves a variety of geometries and modes of motion. The mantle transition zone is an important barrier to subsidence, where subduction slabs stagnate, deform and lithosphere material accumulation. Plate in some areas can be subducted to the core-mantle boundary, the accumulation of the formation of plate cemetery, resulting in D’’ layer material composition and thermal heterogeneity. High-temperature and high-pressure experiments and rheological calculation simulation provide new constraints on the composition and physical properties of the mantle. During the subduction of the mantle, plate mineralization involves the constraints of mineral phase transitions, viscosity, density, and mechanical strength of the carbendazim, Mantle transition zone is an important interface of phase change. Based on the study of plate subduction, a new mode of global convection of the mantle is proposed. The plate grave has a causal relationship with the super mantle plume and has become an important link in global mantle convection and needs further study. Plate subduction is the connection between the superficial plate tectonics and deep super mantle plumes and an important driving force.