用离散元数值模拟法研究克拉苏构造带盐构造变形机理

摘要

为研究库车坳陷克拉苏构造带盐构造挤压变形演化过程及其主控因素,采用离散元数值模拟方法,模拟了阿瓦特段、大北段和克深段3条主干地震剖面的盐构造变形演化过程.离散元数值模拟结果表明,挤压背景下盐岩层表现为塑性变形特征,具有较强的流动性,盐上层、盐岩层和盐下层为整体挤压、分层变形的构造特征;盐下层发育一系列由北向南的冲断构造,盐上层发育断层传播褶皱和滑脱变形构造;先存断裂主要控制盐下层构造变形和应力的传播范围;先存盐底辟主要影响盐上层构造的隆升范围,盐岩展布形态和基底古隆起主要影响盐上层构造变形.研究结果揭示了克拉苏构造带盐构造的动力学演化过程,有利于提高对盐构造变形机理和演化过程的认识.%In order to research the tectonic compressional deformation and its main controlling factors of salt structures in Kelasu structural belt of Kuqa depression,the paper simulates the salt tectonic deformation process of the 3 major seismic sections of Awat,Dabei and Keshen segments by using discrete element numerical simulation method.The simulation results show that the salt bed exhibits plastic deformation under the compressional setting and has relatively strong fluidity.Post-salt,salt and pre-salt beds show some structural characteristics of overall compression and layered deformation.A series of NS trending thrust structures are developed in pre-salt beds,and fault propagating folds and detached deformation structures are developed in post-salt beds.Pre-existing fractures mainly control pre-salt tectonic deformation and stress propagation range,pre-existing salt diapirs mainly influence the tectonic uplifting range of post-salt beds;salt rock distribution and palaeohigh of basement mainly impact the tectonic deformation of post-salt beds.The study results reveal the dynamic evolution process of salt structures in Kelasu structural belt,which will benefit to improve the understandings on salt tectonic deformation mechanism and its evolution process.