东营凹陷辛镇构造带构造变形的物理模拟研究

An Analysis of Physical Modeling of Tectonic Deformation in the Xinzhen Structural Belt of the Dongying Depression

东营凹陷辛镇构造带底辟动力机制及“负花状”断裂形成的主控因素一直存有争议。通过地震资料精细构造解析,结合地层组合特征,设计含塑性层构造物理模拟实验,开展辛镇构造带构造沉积演化研究。根据构造带的地质特征及构造物理模拟结果,分析其深部底辟构造的动力机制,探讨伸展构造背景下塑性层的变形特征及其与上覆岩层的相互作用。取得了以下主要认识:①在盆地伸展构造背景下,坡坪式基底断层活动导致上盘岩层的地势起伏,后期同构造沉积产生的差异沉降诱发底辟发育;②辛镇构造带“负花状”断裂是底辟和区域伸展共同作用的结果,塑性层为断裂发育提供了良好的滑脱条件。

There have been disputes about the diapiric dynamic mechanism for plastic layer and the main controlling factors for the formation of the “negative flower-like” fault groups in the Xinzhen structural belt of the Dongying depression.The fine tectonics of seismic data and combining with the characteristics of stratigraphic assemblage is analyzd .The physical modeling with plastic layer to physically simulate tectonic and sedimentary evolution of the Xinzhen structural belt is designed.According to the geological characteristics of the Xinzhen structural belt and the results of physical modeling,the dynamic mechanism of the diapir structure is analyzed,and the deformation characteristics of the plastic layer under the extensional tectonic background and its interaction with the overlying strata is discussed.Some conclusions have been reached:① Under the extensional tectonic setting of the basin,the activity of slope-flat basement faults results in the topographic fluctuation of the strata in the upper wall,and the diapir is triggered by differential subsidence induced by later syntectonic sedimentation.② The “negative flower-like” fault groups in the Xinzhen structural belt is the result of diapir and regional extension,and the plastic layer provides a good detachment layer for fault development.