塔里木盆地顺南地区走滑断裂发育特征及演化

    DEVELOPMENT AND EVOLUTION OF THE STRIKE-SLIP FAULTS IN SHUNNAN AREA, TARIM BASIN

    • 摘要: 顺南地区位于塔里木盆地塔中隆起北部.受多期构造应力影响,该地区以走滑断裂大量发育为典型特征.对三维地震资料的精细解释和深入分析结果表明,研究区走滑断裂具有垂向分层、平面分段、多期次构造叠加的特征.顺南地区主要发育北东、北东东和北西向3组走滑断裂.北东向断裂活动性强,平面上发育雁列式断层及马尾状构造,剖面上主要发育对称花状、正花状与负花状上下分层叠置的复合花状构造.北东东和北西向断裂活动性较弱,剖面上以单条直立走滑断裂为主,平面上呈线性延伸或由多段同向走滑断层连接而成.根据断层构造样式和受力性质,将顺南1断裂沿走向划分为4段:2个复合花状-拉张段和2个简单花状-挤压段,拉张段和挤压段沿走向交替出现.顺南走滑断裂的形成主要经历了5期构造运动:加里东早期、加里东中期Ⅰ幕、加里东中期Ⅲ幕、加里东晚期-海西早期和海西晚期.其中,加里东中期Ⅰ幕和加里东中期Ⅲ幕为该区主要断层活动期.

       

      Abstract: Shunnan area, located in the northern Tazhong uplift of Tarim Basin, is affected by multi-stage tectonic stress with a large number of developed strike-slip faults. Detailed interpretation and deep analysis of 3D seismic data show the faults are varied in vertical and plane views with multi-stage structural superposition. There are mainly 3 groups, i.e. NE, NEE, and NW, of strike-slip faults developed in the study area. The NE-trending faults are highly active, with en echelon and horsetail structures developed on the plane, and composite flower structures of symmetric flower, positive and negative flowers superimposed on the profile; while the NEE and NW faults are less active, with single vertical strike-slip fault dominated on the profile, and linear extension or multi-section synthetic strike-slip faults connected on the plane. According to the structural style and stress property, the FSN1 can be divided into 4 segments along the strike, including 2 composite flower-tensional segments and 2 simple flower-compressional segments, which occur alternately along the strike. The strike-slip faults mainly went through 5 stages of tectonic movements:the Early Caledonian, Episode I of Middle Caledonian, Episode Ⅲ of Middle Caledonian, Late Caledonian-Early Hercynian and Late Hercynian, among which, the second and third are the main stages for fault activity.

       

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