中非剪切带多赛奥盆地构造特征与构造样式研究

Tectonic chaiacteristics and tectonic style of Duoaosai basin in central Africa shear zone

通过对中非剪切带构造演化的研究,并结合盆地构造特征的分析,明确了早白垩世中非剪切带强烈右旋走滑作用控制了多赛奥盆地的形成。晚白垩世,非洲板块与欧亚板块发生碰撞,区域应力场发生改变,形成了南北向的挤压应力场。对中非剪切带构造特征精细解剖与分析表明,晚白垩世盆地至少发生了三幕挤压作用,盆地发生明显的构造反转,形成反转背斜、花状构造等多种构造样式,为圈闭的形成奠定了良好的基础;同时,该时期主力烃源岩也开始进入大量排烃阶段,构造活动形成的断裂也为油气运移创造了优越的条件。

Through the structural evolution study of central Africa shear zone,in combination with the structure characteristics of the basin,it was made clear the formation of Duoaosai basin was controlled by the strong right-lateral strike-slipping.In late cretaceous,the African plate collided with the Eurasian plate and the regional stress field changed,which resulted in the formation of the northsouth extrusion stress field.Elaborate analysis of the central Africa shear zone indicated there were at least three events of tectonic compression and the apparent reversal occurred in the structure of the basin,which formed a variety of tectonic styles such as reversal anticline and flower-like structure,which laid a good foundation for trap formation.Meantime,the hydrocarbon source rocks in this period also began to enter hydrocarbon expulsion stage in large scale,the fracture formed by the tectonic movement created advantageous conditions for hydrocarbon migration.