【摘要】 从逆冲推覆构造、走滑构造、伸展构造3个方面对喜马拉雅-青藏高原造山带内的新生代(印度-亚洲大陆碰撞之后)构造最新进展进行了总结和分析.基于这些资料,提出青藏高原内部变形的3个阶段:始新世(50~33 Ma),青藏地区总体呈刚性,变形集中在造山带的南北周缘;渐新世-中新世初(33~22 Ma),高原中西部以逆冲断层形式的散布式挤压变形,以东部大型走滑断层为边界的块体挤出与块体旋转3种变形方式共存;中新世初至今(22~0 Ma),高原块体的强度进一步变弱,以遍及高原整体的连续散布变形为主,出现共轭走滑断层与伸展构造.认为南北走向的地堑(正断层)是同样处于东西伸展应力体系下的藏中共轭走滑断层向造山带南北延伸扩展的产物.此外,还对造山带内会聚量的调节方式进行了定量的分析和估算.更多还原

【Abstract】 This paper summarized the Cenozoic deformational characteristics of the Himalayan-Tibetan orogen caused by the Indo-Asian collision,in view of compressional,extensional,and strike-slip structures.Based on these data,we proposed that the Cenozoic deformation of Tibet-Himalaya can be divided into three stages: during the Eocene(50~33 Ma),the interior of Tibet plateau was rigid,and deformation was concentrated on the northern and southern rims of Tibet-Himalaya;from the Oligocene to the earliest Miocene(33~22 Ma),its central and western segments were characterized by distributed contractional deformation in mode of thrusts whereas its eastern segment was associated with extrusion and rotation along the larger strike-slip faults;since the earliest Miocene,Tibetan lithosphere became much weaker and deformed in a continuous and diffused way,leading to short conjugated strike-slip faults and extensional structures.We also pointed out that the N-S trending rifts are the products of coevally northward and southward propagation of the conjugated strike-slip faults in central Tibet plateau under the E-W stretching stress.Moreover,we also estimated the proportions of the two modes of accommodation for the large convergence in the Himalayan-Tibetan orogen.更多还原