后撤式逆冲推覆断层成因机制及物理模拟——以准噶尔盆地西北缘克-百断裂带为例

发布时间：2018-07-16 18:53

【摘要】：位于准噶尔盆地西北缘中段的克-百断裂带,晚二叠世以来发育了一系列后撤式逆冲断层。长期以来,关于克-百断裂带高角度逆冲断层的成因机制一直处于争论当中,后撤式逆冲断层的物理模拟在国内尚未见文献报道。论文通过地震解释研究了克-百断裂带的构造变形特征及其演化阶段;应用断层"活动性系数"理论,半定量地描述了挤压条件下断层"活动性系数"、摩擦系数与断层倾角之间的关系,证明了挤压条件下也能形成高角度逆断层;结合"造山楔"理论解释了后撤式逆冲断层的成因机制。研究认为,克-百断裂带后撤式逆冲断层是印支期、燕山期持续挤压和扎伊尔山隆升效应综合作用的产物:挤压过程中发生"泊松效应",随着断层倾角增大,断层面上的正压力迅速增大、"活动性系数"降低,当倾角增大到一个临界值后断层停止活动,形成高角度的逆断层;同时扎伊尔山隆升造成挤压应力上移,为断层的后撤奠定了基础。最后利用砂箱物理实验模拟了克-百断裂带后撤式逆冲断层的形成过程。
[Abstract]:Since late Permian a series of retreating thrust faults have been developed in the Ke-Bai fault zone located in the middle part of the northwestern margin of Junggar Basin. For a long time, the genetic mechanism of high-angle thrust fault in the Ke-Bai fault zone has been in dispute, and the physical simulation of the withdrawal thrust fault has not been reported in domestic literature. In this paper, the tectonic deformation characteristics and evolution stage of Ke-Bai fault zone are studied by seismic interpretation, and the theory of fault "activity coefficient" is applied. The relationship between the "activity coefficient" and the friction coefficient and the dip angle of the fault under the extrusion condition is described, and it is proved that the high angle reverse fault can also be formed under the extrusion condition. Combined with the orogenic wedge theory, the origin mechanism of the recoil thrust fault is explained. It is considered that the recoil thrust fault of the Ke-Bai fault zone is the product of the combination of the continuous compression of the Indosinian period, the Yanshanian period and the uplift effect of the Zairian Mountains: the Poisson effect occurs during the extrusion process, and with the increase of the fault dip angle, The positive pressure on the fault plane increases rapidly, and the "activity coefficient" decreases. When the dip angle increases to a critical value, the fault ceases to be active and forms a high-angle reverse fault. At the same time, the uplift of the mountain of Zaire causes the upward displacement of the compressive stress. It lays the foundation for the back-down of the fault. Finally, the formation process of withdrawal thrust fault in Ke-Bai fault zone is simulated by sand box physical experiment.
【作者单位】：中国石油勘探开发研究院;中国石油杭州地质研究院;中国石油大学(北京)地球科学学院;
【基金】：国家自然科学基金(41372116) 中国石油集团科技重大专项(2014E-32-09)联合资助
【分类号】：P542

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