塔里木盆地巴楚中部地区寒武系盐下构造发育特征

Developmental characteristics of Cambrian subsalt structures in central Bachu area,Tarim basin

巴楚中部地区寒武系盐下构造的发育主要受断裂活动的控制。现存的构造圈闭都经过多期构造运动的改造。卡北构造、古董山构造和卡拉沙依构造分别在海西晚期和中生代早期达到最佳圈闭形态。后期构造运动对早期构造圈闭起到改造、破坏作用 ,使卡北构造由背斜向断背斜转变 ,卡拉沙依由背斜向断背斜、断鼻形态发展 ,闭合幅度都有所减小。古董山构造圈闭则是由于后期断层使原构造圈闭破碎、条带化 ,以及喜山期构造运动造成构造带南北向不等量抬升 ,构造带北高南低 ,从而失去了形成较大局部圈闭的条件。康塔库木构造圈闭形成时间短 ,形成于喜山中期 ,加强于喜山晚期 ,圈闭幅度也进一步增大。

Development of the Cambrian subsalt structures in central Bachu area has mainly been controlled by fault movements.The present structural traps have been modified by multiphase tectonic movements.Kabei,Gudongshan and Karasay structures have reached their optimal trap shapes in Late Hercynian and Early Mesozoic,respectively.The structural traps have then been modified and destroyed by later structural movements,as a result,Kabei structure has been transformed from anticline into faulted anticline,while Karasay structure from anticline into faulted anticline and faulted nose.The closures of both structures have been reduced to some extent.In contrast,Gudongshan structure has lost the condition of forming relatively large local traps,because later faults have broken the original structural traps into strips,and the Himalayan tectonic movement has unevenly uplifted the structural belt and become low in the south and high in the north.Kangtakumu structural trap has been formed in a relatively short time,i.e.it has been formed in Middle Himalayan and strengthened in Later Himalayan stage,and the closure has also been enlarged.