坳陷湖盆坡折带特征及其对非构造圈闭的控制

Characteristics of slope breaks and their control on atectonic traps in downwarped lake basin

对准噶尔盆地西北缘地区侏罗系层序地层学的研究表明 ,在该地区发育多级坡折带。按其成因机制可分为断裂和挠曲坡折带 ,根据自然地理位置又可将坡折带分为盆缘坡折带和盆内坡折带两大类。构造运动是坡折带发育的主控因素 ,而且其规模与构造运动大小相关。多级坡折带对非构造圈闭的控制主要表现为 :①非构造圈闭紧邻多级坡折带发育 ,沿着坡折带呈串珠状展布 ;②非构造圈闭在纵向上发育具有继承性 ;③非构造圈闭发育的类型随着坡折带和坡折带所处的地理位置的不同而有所不同 ;④同一个坡折带在横向上存在较大的变化 ,可形成不同类型的非构造圈闭 ;⑤多级坡折带的存在导致了在盆地的不同地理位置发生不同的沉积剥蚀响应 ,非构造圈闭的生、储、盖组合较好 ;

The study on the sequence stratigraphy in Jurassic system of the northwestern area of Junggar Basin shows that there mainly developed multiple slope breaks.Those slope breaks can be divided into faulted slope break and bending slope break according to their genetic types and can also be divided into basin margin slope break and inner-basin slope break according to their natural geographical positions.The atectonic movement is the dominant factor for developing the slope breaks,and the scale of slope breaks intimately relates with the size of tectonic movement.The controls of multiple slope breaks on tectonic traps have following features.The atectonic traps were developed near the multiple slope breaks and distributed in beads-shape along the slope breaks.In the longitudinal direction,the development of atectonic traps was characterized by the inheritance.The different slope breaks and their different geographical positions resulted in the different development types of atectonic traps.Any slope break could form different kinds of atectonic traps,owing to its great variation laterally.The existence of multiple slope breaks resulted in the different responses of erosion and deposition in the different geographical positions of Junggar Basin.The source-reservoir-seal assemblage of atectonic traps is fine.The atectonic traps controlled by slope breaks had very favorable oil-bearing conditions.