东营凹陷新生代早期断裂系统的运动学特征及动力学机制

Fault systems kinematic characteristics and dynamic mechanism during early Cenozoic in Dongying sag

通过对盆地地震剖面的解释,构造演化剖面的编制,断层运动学三维解析以及前人对地热场、地球物理场研究的分析,对东营凹陷新生代早期断裂的运动学特征和动力学机制进行研究。结果表明:在新生代早期,东营凹陷在伸展过程中发育有走滑-正断层和走滑断层,其中走滑-正断层在剖面上为马尾状断层组合;东营凹陷新生代早期东西向伸展量小、南北向伸展量大,在主要伸展期Ek-Es4伸展了15.1 km,而断层走滑量分析表明NW、NE向正断层在走滑量分别为14.8 km和10.3 km;东营凹陷新生代早期的伸展为窄裂陷模式,表现为强烈断陷;凹陷内NW、NE向断层对南北向伸展起侧断调节的作用,而凹陷周边发育的展向断层由调节块体向南逃逸时的伸展差异产生。

Based on interpretation of seismic profiles,compilation of tectonic evolution sections,3-D analysis of fault kinematics,and combining the former study on geothermal field and geophysical field,the fault system＇s kinematic characteristics in Dongying sag and their dynamic mechanism during early Cenozoic were discussed.The results show that strike-slip faults and strike-slip normal faults are the major fault types developed in Donying sag in early Cenozoic.The former are typically ＂horsetail＂ shaped,and are usually accompanied with secondary faults in vertical sections.Besides,Dongying sag extended mainly in the south-north direction as opposed to the east-west direction,and accumulated 15.1 km during Ek-Es4.In addition,the strike-slip displacements of the NW and NE trending faults are 14.8 km and 10.3 km,respectively,estimated from their associated displacement vectors.The sag extended by narrow rift mode in early Cenozoic,and later became extensive subsidence stage.The NW and NE trending faults in the sag worked as the lateral ramp for the N-S extension,and the transfer faults in south of the sag were produced by the horizontal differential extension when the blocks moved to the south.