摘要
青藏高原北部(东昆仑山-唐古拉山)新生代以来的构造变动,可能是印度板块与欧亚板块碰撞后产生强大板内变形扩展的结果。主要表现为强烈的上隆,在σ_1垂直作用下的水平伸展与挤压作用的交替,盆-山体系的形成,裂谷型火山活动及大规模纵向走滑作用造成的块体逐一向东挤出。利用天然地震对岩石圈进行探测,发现岩石圈下部(下地壳及岩石圈地幔,60-120 km)存在高、低速层紧密相间的水平分带及具左行走滑的岩石圈断裂。综合地质与地球物理资料,本文提出了高原深部地幔底辟作用,建立了高原北部隆升的深部构造物理作用动力源的新模式。
The tectonic activities since the Cenozoic in the region of the Kunlun and Tanggula mountains in the northern part of the Qinghai-Tibet plateau are represented by substantial uplift of the plateau, alternation of horizontal extension and compression due to the σ1 vertical action, rift-type volcanic activity, formation of the basin-range system, and eastward extrusion of blocks from the plateau caused by the strong intraplate deformation propagation after the collision between the Indian plate and the Eurasian plate. Research on the lithospheric structure through seismic converted waves indicates that in the region the lower crust and lithospheric mantle, at depths between 60 - 120 km, have a "multi-sandwich structure" which is frequently altered by high-velocity and low-velocity horizontal layers, and have lithosphere faults with a strike-slip sense. The 70 km thick anisotropic layer reflected by the shear wave in the region of the Kunlun and Tanggula mountains is considered to be equal to the alternating high-velocity and low-velocity layers in the lower part of the lithosphere (lower crust plus litho-mantle) , representing the directions of the shear vectors. By integrating the geological and geophysical data, the paper proposes a model of mantle diapir to explain the tectonophysics and dynamic source at depth for the uplift of the northern part of the Qinghai-Tibet plateau.
出处
《地质学报》
EI
CAS
CSCD
北大核心
1996年第3期195-206,共12页
Acta Geologica Sinica
基金
地质矿产部
国家科委国际合作司及法国宇宙科学研究院所支持中法"东昆仑及邻区岩石圈缩短机制"项目
关键词
青藏高原
地球物理
隆升
地幔底辟
深部构造
northern part of the Qinghai-Tibet plateau
geophysics
uplift
mantle diapir
