北部湾盆地北部坳陷新生代断裂发育过程研究

FAULTING MECHANISM IN NORTHERN DEPRESSION OF THE BEIBUWAN BASIN,CHINA

北部湾盆地北部坳陷是北部湾地区重要的油气产区,其新生代沉积盆地演化以及坳陷发育过程受边界断层发育的控制。为了阐明新生代断裂系统发育及其对沉积的控制作用,结合构造应力场研究分析了盆地断裂系统的动力学成因,利用正断层位移-长度法研究了几条边界断层的发育过程,编制不同时期沉积厚度图印证了凹陷沉降中心的迁移过程及其与断裂发育的匹配关系。认为四条主干断层分别具有不同的活动时期和各自的活动中心,同时控制了不同的沉积凹陷的发育。

The northern depression of the Beibuwan basin is one of the important oil and gas producing areas. Basin evolution and depression migration in the Cenozoic were controlled by the boundary faults. To clarify the controlling mechanism, several boundary faults were studied based on the relationships of displacement and rupture length and the analysis of structural stress field. Thickness of sediments was presented to prove the migration of sedimentary axises, and it well matched the migration histories of the controlling faults. It was concluded that the four boundary faults developed during different time periods accordingly controlled the different sedimentary depressions.