Geodynamics of the Baikal rift zone and plate tectonics of Asia
Geodynamics of the Baikal rift zone and plate tectonics of Asia
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DOI：
10.1016/0040-1951(81)90251-1
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发表时间：
1981-06
期刊：
影响因子：
2.9
通讯作者：
L. Zonenshain;L. Savostin
中科院分区：
文献类型：
--
作者：
L. Zonenshain;L. Savostin
贝加尔裂谷带从贝加尔湖南端延伸至118°E，包括贝加尔盆地和巴古津、上安加拉和Muysk地堑，形成其东部延伸。与裂谷带相重合的是一条狭窄的地震带，它沿着斯塔诺托山脉向东沿着一直延伸到鄂霍次克海。该带可以被认为是欧亚板块和阿穆尔板块之间的边界。地震震源机制解表明，贯穿裂谷带走向的伸展轴方向一致，表明欧亚板块和阿穆尔板块作为刚体的行为。根据83个震源机制解，计算出欧亚板块和阿穆尔板块的旋转极位于56.95N117.45E点。根据贝加尔湖的开放量估计，角速率约为1.10− 7度/年。极的位置在裂谷带的东部终端占的裂谷带的消亡和外观的极东部，在斯坦诺山脉的压缩结构。在西南方向，贝加尔裂谷带被中亚的微板块镶嵌所取代，这些微板块占据了欧亚大陆和印度岩石圈板块之间的空间。突出的是蒙古、准噶尔、阿拉善、塔里木、西藏和帕米尔微板块。中亚的地震是分散的，尽管与微板块边界有关的地震的高度集中是突出的。中亚的构造被认为是由于刚性微板块的相互作用，假设塑性变形发生在相对较宽的区域内沿着微板块边界。通过考虑走滑断层来定义微板块运动轨迹，计算了微板块相对运动参数。由于印度和欧亚大陆的碰撞和继续聚合，中亚的微板块镶嵌体正向东北方向移动。马赛克就像一个楔子，把阿穆尔板块从欧亚大陆分裂出来，使它逆时针旋转，从而打开了贝加尔裂谷。
The Baikal rift zone stretches from the southern termination of Lake Baikal as far as 118°E, and includes the Baikal basin and the Barguzin, Upper Angara and Muysk grabens that form its easterly continuation. Coincident with the rift zone is a narrow seismic belt which extends further east along the Stanovoy range to the Okhotsk Sea. This belt can be considered as the boundary between the Eurasian and Amurian lithospheric plates. Earthquake focal-mechanism solutions that show a consistent orientation of extensional axes across the strike of the rift zone indicate the behaviour of the Eurasian and Amurian plates as rigid bodies. From 83 focal mechanism solutions, the pole of rotation of the Eurasian and Amurian plates was computed to lie at the point 56.95N 117.45E. The angular rate, estimated from the amount of Baikal opening, is about 1.10−7deg/year. The position of the pole at the eastern termination of the rift zone accounts for the dying-out of the rift zone and for the appearance east of the pole, of compressive structures in the Stanovoy range. To the southwest the Baikal rift zone is replaced by the mosaic of microplates in Central Asia that occupy the space between the Eurasian and Indian lithospheric plates. Prominent are the Mongolian, Dzungarian, Alashan, Tarim, Tibetan and Pamir microplates. Earthquakes in Central Asia are dispersed although higher concentrations of earthquakes associated with microplate boundaries are prominent. The tectonics of Central Asia are considered to be due to the interaction of rigid microplates, assuming that plastic deformations occur within the relatively wide zones along the microplate boundaries. By considering the strike-slip faults to define the trajectories of microplate motions, the parameters of relative movements of the microplates have been computed. The microplate mosaic of Central Asia is moving northeasterly, as a result of the collision and continued convergence of India and Eurasia. The mosaic acts as a wedge splitting off the Amurian plate from Eurasia causing it to rotate counterclockwise so opening the Baikal rift.