中非剪切带裂谷盆地类型划分及形成机制

Types and formation mechanism of rift-basins in Central African shear zone

 孔令武 韩文明 张树林 赵红岩 喻英梅 赵佳奇

 中海油研究总院，北京100028

 CNOOC Research Institute, Beijing 100028, China

 从盆地结构和构造特征分析入手，立足于中非剪切带的构造演化，划分了中非剪切带裂谷盆地的类型，比较了不同类型盆地的构造差异，探讨了不同类型盆地的形成机制。研究表明：中非剪切带经历了强、弱2期走滑作用，中非剪切带强烈走滑作用控制了裂谷盆地的形成，沿该剪切带形成了伸展盆地和走滑-拉分盆地，大型走滑断裂的走滑断块末端水平位移变换控制了穆格莱德、迈卢特、多巴等伸展盆地的形成；走滑断裂中部的弯曲形态和走滑运动方向的有效配置控制了多赛奥和塞拉迈特等走滑￣拉分盆地的形成。早白垩世中非剪切带强走滑作用使2种盆地均发生强烈裂陷作用，广泛发育中、深湖相沉积，控制了湖相优质烃源岩的发育。

 Starting from the analysis of basin structure and tectonic characteristics, based on the tectonic evolution of Central Africa shear zone, the types of the rift basins in Central African shear zone are divided; the structural differences of different types of basins are compared, and the formation mechanisms of different types of basins are discussed. Studies show that Central Africa shear zone experienced strong and weak strike-slip stages, and the strong strike-slip in Central Africa shear zone controlled the formation of the rift basins, along which extensional basins and strike-slip pull-apart were formed. The transformation of horizontal displacement in the end of large-scale strike-slip fault zone controlled the formation of extensional basins, such as Muglad, Melut and Doba basins; the effective configuration of bending shape and strike-slip direction controlled the formation of strike-slip pull-apart basins, such as Doseo and Salamat basins. In Early Cretaceous, strong strike-slip in Central Africa shear zone led both types of basins to intense rifting and extensive development of middle and deep lacustrine facies deposits, which controlled the development of lacustrine high-quality source rocks.

10.6056/dkyqt201804001