中西非裂谷系形成的动力学机制  

DYNAMIC MECHANISM OF RIFT SYSTEMS IN WEST AND CENTRAL AFRICA

作　　者：张庆莲 侯贵廷[2] 潘校华[3] ZHANG Qinglian;HOU Guiting;PAN Xiaohua(College of Resources,Hebei GEO University,Shijiazhuang 050031,Hebei,China;School of Earth and Space Sciences,Peking University,Beijing 100871,China;Petro-China Exploration&Development Research Institute,Beijing 100083,China)

机构地区：[1]河北地质大学资源学院,河北石家庄050031 [2]北京大学地球与空间科学学院,北京100871 [3]中国石油勘探开发研究院,北京100083

出　　处：《地质力学学报》2018年第2期169-176,共8页Journal of Geomechanics

基　　金：中石油勘探开发研究院和国家重点基础研究发展计划"973"项目(2009CB219302);河北地质大学博士科研启动基金项目(BQ201602)

摘　　要：中西非裂谷系是沿中非剪切带及邻区发育的一系列中新生代裂谷盆地,其成因机理一直存在争议。中西非裂谷系的构造演化主要经历了三个演化阶段,其中在早白垩世进入强烈断陷期,是盆地形成的重要阶段。以早白垩世中西非裂谷系的地质背景为基础,运用弹性力学有限元数值模拟方法,通过应力场和应变场的分析,为中西非裂谷系形成的力学机制提供依据。模拟结果表明,早白垩世非洲大陆内部走滑和伸展作用并存,中非剪切带不是所谓的"转换断层",而是与中西非裂谷系同时形成和发育的构造。中西非裂谷系是在中新生代泛大陆裂解时期,非洲板块绕西北非地块逆时针旋转,非洲内部不同地块在统一构造应力场作用下,由于伸展和走滑的差异作用形成和发育的。The rift systems in West and Central Africa that developed along the shear zone in Central Africa is a series of Mesozoic-Cenozoic rift basins,and their formation mechanism is still a matter of debate.The evolution of those rift systems has three stages,and Early Cretaceous is the most important one for the basin formation,in which the rifts and major fault zones were strongly active.Based on the geological setting of rift systems in West and Central Africa in Early Cretaceous,using linear elastic theory with two dimensional finite element numerical simulation,through the analysis of the stress field and the strain field,reliable evidence to the mechanical mechanism of rift systems are produced.The simulation results suggest that strike-slipping and extensional process coexist in African continent in Early Cetaceous,and the shear zone in Central Africa is not a“transform fault”but a structure that formed and developed simultaneously with the rift systems in West and Central Africa.In Mesozoic-Cenozoic Pangea disintegration period,due to the different motion rates of the three blocks along parallel slip vectors under the unified tectonic stress field and the counterclockwise rotation around WB by African plate,rift systems were formed and developed.

关 键 词：中西非裂谷系 中非剪切带 早白垩世成盆 有限元数值模拟 力学机制 

分 类 号：P542[天文地球—构造地质学] P628.3[天文地球—地质学]