周口坳陷叶鲁断裂带构造特征及其演化

Structural Features and Evolution of Yelu Fault Belt in Zhoukou Depression,Southern North China

叶鲁断裂带位于华北克拉通南部,是鲁山-舞阳-阜阳-淮南断裂带的重要组成部分,控制着周口坳陷谭庄、舞阳等凹陷的形成与演化。据钻井、地震剖面解释和平衡剖面分析,在秦岭-大别造山带挤压活动的影响下,叶鲁断裂带在晚侏罗世—早白垩世向NNE方向强烈逆冲,主断层面倾角约37°,伸展率可达-22 m/Ma;晚白垩世—古近纪,周口坳陷处于伸展构造环境,该断裂带发生负反转构造作用。通过三角剪切软件模拟了叶鲁断裂带主断层在周参12井区的构造演化过程。模拟显示主断层形成时的总滑动量约为6 100 m,断层传播量为9 150 m,三角剪切角为150°,p/s值为1.5。

Located in the southern North China Craton,Yelu fault belt is an important part of Lushan-Wuyang-Fuyang-Huainan fault belt,which controls the formation and evolution of Tanzhuang Sag and Wuyang Sag in Zhoukou depression.It was affirmed through drilling analysis,seismic profile interpretation and balanced cross section analysis that under the influence of Qinling-Dabie orogenic activity,Yelu fault belt strongly thrusted towards NNE,with about 37° fault dip and fault activity rate of-22 m/Ma during the Late Jurassic and Early Cretaceous;occurred in the Late Cretaceous and Paleogene,the negative inversion of Yelu fault belt was related to the extensional environment in Zhoukou depression.The tri-shear model is applied to stimulating the structural and evolutionary processes of Yelu fault belt nearby the well ZC 12.The result shows that during the Late Jurassic and Early Cretaceous,fault slip of Yelu fault belt amounts to 6,100 m,and fault propagation is 9,150 m as well as p/s is 1.5,with the trishear angel of 150°.