众多地震测深剖面的地质构造解析显示,大陆岩石圈存在既有显著差异又有密切联系的两套断裂系统,即以地壳表层脆性剪切带为主的浅层断裂系统和以切割莫霍界面的壳幔韧性剪切带为主的深部断裂系统。根据地震测深速度结构特征,结合深部构造岩石地球化学的综合研究,将切割莫霍界面或壳幔过渡带的壳幔韧性剪切带划分为三类(俯冲带、缝合带和剪切带)五型(大陆岩石圈边缘海沟俯冲带、大陆岩石圈碰撞缝合带、挤压型壳幔韧性剪切带、伸展型壳慢韧性剪切带和走滑型壳幔韧性剪切带)。建立起中国大陆岩石圈构造变形由地壳表层向深部扩展以及由壳幔过渡带向地壳中上部扩展的岩石圈双向扩展模式。壳幔韧性剪切带既是无机成因天然气等深部流体的通道,又是地震活动区的发震构造之一,因此研究大陆岩石圈壳幔韧性剪切带具有重要学术价值和实际意义。
The structural analyses of many seismic sounding profiles indicate that there are two fault systems in China continental lithosphere, which are different obviously and correlative closely: one is the shallow fault system composed of ductile-brittle shear zones mainly in surface crust, and the other is deep fault system mainly composed of crust-mantle ductile shear zones, which cuts the Moho. Based on the characteristic of seismic wave velocity and the result of petrology and geochemistry of deep structure, we divide the system of crustmantle ductile shear zones in China continental lithosphere into three classes and five types: (1) trench subduction zones in marginal sea of continental lithosphere; (2) collision suture belts in continantal lithosphere; (3) compressive ductile shear zones for crust-mantle; (4) expanded ductile shear zones for crust-mantle; (5) strike-slip ductile shear zones for crust-mantle. Then we construct a model of tectonic deformation of China continental lithosphere, which expands from the surface to the deep and from the crust-mantle transition zone to the upper and middle crusts. As the crust-mantle ductile shear zone is both a channel for inorganic origin gas and one of the earthquake-generating structures in the seismic activity area, the research of crust-mantle ductile shear zone is of great academic value and of practical significance.