沾化凹陷断层对沉积的控制作用

Controlling of faults on sedimentation in Zhanhua sag

应用断层落差法对沾化凹陷断层活动规律进行了研究。结果表明,该区断层具有幕式活动的特点,即在沙三早期断层活动强烈,沙三中、晚期—沙二早期断层活动变弱,沙二晚期—沙一早期断层活动又变强烈,东营早期和晚期断层活动又变弱。断层的幕式活动控制了各时期沉积地层的厚度和空间展布形态,使得沉降中心以五号桩长堤断裂带附近为起点进行顺时针迁移;断层活动的性质控制了沉积物内部的叠加方式,即张性断层活动时期以发育退积式准层序组为主,压性断层活动时期以发育进积式准层序组为主。同时,断裂的不同组合样式也控制了砂体的发育和空间展布。

The laws of fault activities in Zhanhua sag were studied by fault fall method. The results show that fault activities are characterized by episodic. During the early Es3 tectonic activities were intensive. During the middle Es3 and the period from late Es3 to the early Es2 tectonic activities were weak and during the period from the late Es2 to the early Es1 tectonic activities became intensive while to the period of Ed tectonic activities became weak again. Fault episodic activities con- trolled the thickness and spatial distribution of each strata, which induced that sedimentary center migrated clockwise with the area near to Wuhaozhuang fault zone as start point. The type of fault activities controlled the overlapping mode of sedi- ments, which could be indicated by that the progradational sequence was developed mainly during the period of extensional fault activities and the retrograding sequence was developed mainly during the period of compressive fault activities. At the same time the combined styles of faults also controlled the development and spatial distribution of sandstone.