攀西裂谷的力学成因机制和模型实验

裂谷是在引张力作用下产生的,并根据裂谷切割深度确定其类型。据世界上多数裂谷资料证实,它们均切穿了岩石圈。当然,也有切割不深的裂谷(只切穿沉积盖层)。从断块学说观点看来,裂谷的形成是受断裂体系控制的,以地幔上涌为动力,具全球规模,延伸数百至数千公里的狭长断陷带。

PRELIMINARY NOTE ON MECHANISM OF FORMATION OF PANXI RIFT

In this paper, we calculated ∑ value of Panxi Rift by Artyushkov’s equation (1982), which is:∑～4.7×10⁹ bar·cm and value of regional stresses is:σ～1-2k bar　Formation of Panxi Rift was controlled by fault system, and drived by dynamics derived from mantle upwelling. Panxi Rift formed in Palaeozoic Bra, although it revived in Mesozoic and Cenozoic Bras but deformation was not specially strong. During formation and evolution of Panxi Rift, it subjected to stresses derived from mantle up-welling, extension, compression, shear-extension, shear-compression in different geological periods and different degree. Deformation changed from strong to weak and from quick to slow with geologie age.Geological and geophysical characteristics of Panxi Rift are similar to some rift systems in world including a few rifts in China. The similarities between Panxi Rift and others are mainly in respects of the changes of fault system in vertical direction, extend of fault in plane as well as the magma activities etc.During formation and evolution of Panxi Rift there occurred many violent earthquakes ; studies on mechanism of formation of these earthquakes may promote the probe into the mechanism of formation of Panxi Rift.