Abstract:

The main controlling factors for the structural evolution of Qaidam Basin are always the focus for the researchers in China. This study on the practical information shows that there is a regional Qaizhong Fault from east to west in Qaidam Basin. This fault was formed during the Proterozoic Era and composed of several mid-small faults in some areas. It becomes a crust suture zone between the craton of South Qaidam and the hyperplasia of North Qaidam. This crust suture zone is one of the main faults affecting the change of the deposition center in Qaidam Basin. Since the Mesozoic Era,Qaizhong Fault has become a part of Altyn Strike-slip Fault with characteristics of slipping while depositing. The topography, formations, structure and gravity magnetic field are obviously different along both sides of Qaizhong Fault. The real Qaidam Block was separated from Qaidam-Qilian Block in the Caledonian and experienced two times of basin formation in Hercynian and Yanshanian-Himalayan periods. Qaizhong Fault controlled the processes of basin formation, evolution and hydrocarbon enrichment.

Key words: Qaidam Basin, Qaizhong Fault, structural evolution, basin formation, main controlling factor

摘要：

柴达木盆地构造演化的主控因素一直是人们关注的焦点。对多种实际资料的再次研究表明:柴达木盆地中部东西向横亘着一条区域性断裂带——柴中断裂带。它形成于元古代,是柴南古陆核和柴北增生体之间的地壳缝合带,也是控制柴达木盆地沉积中心转移的主要断裂带之一。中生代以来,柴中断裂带与阿尔金走滑断裂为同一构造活动体系,具有边走滑边沉积的特征,其两侧在地形、地层、构造和重磁场特征方面存在显著差异。柴达木盆地是柴达木地块在加里东期从柴达木-祁连地块中分离出来之后,又经历了海西期和燕山—喜山期两次成盆作用而形成的,柴中断裂带对盆地形成、演化和油气富集具有重要的控制作用。

关键词: 柴达木盆地, 柴中断裂带, 构造演化, 成盆作用, 主控因素