关键词: 贝加尔裂谷, 构造发育, 岩石圈流变学, 物理模拟

Abstract: Baikal Rift is located in the center of the largest continental area in the world, far away from any active plate boundary, but it is one of the most active and complex tectonic areas on earth today. The main controlling factors of its formation and evolution have been widely discussed. Yet, it is still the subject of intense debate concerning. In this paper, the process of lithospheric deformation under the background of local tension is studied by means of physical modeling. Baikal rift is located at the joint of the strong Siberian craton and the weak Sayan-Baikal fold belt. The Siberian craton is characterized by a strong lithosphere where the crust and mantle are mechanically coupled. The experimental results show that stress tends to accumulate on the craton side under the regional tension, and a deep and large fault first developed near the edge of the craton at the weak suture between the craton and orogenic belt. With the continuous extension of the lithosphere, the stress is transferred to the side of the orogenic belt, and the faults also migrate to the side of the orogenic belt, presenting an echelon arrangement. Compared with the young fold belt, the old craton has a cold and hard rigid basement, which determines the narrow and deep depression characteristics of Baikal rift and the asymmetry of its structure.

Key words: Baikal rift, structure, lithospheric rheology, physical modeling