准噶尔西北缘斜向挤压构造与走滑断裂

古板块构造研究表明古生代以来，准噶尔地块以斜向方式拼合到阿尔泰（Altaids）造山带构造域内，导致准噶尔西北缘一直处在斜向挤压构造背景之下，并发育高角度逆冲推覆构造带以及横向走滑断裂。地面地质调查、遥感卫星影像解译、大地电磁测深剖面和地震剖面构造解释资料综合研究表明，准噶尔西北缘边界断裂为达拉布特左行走滑断裂，西北缘逆冲推覆构造带为基底卷入的高角度逆冲断裂褶皱带； 在与逆冲带走向相垂直方向，发育有北西向横向走滑断裂，这些断裂为同一斜向挤压构造背景下形成的同期构造，形成时间约在晚二叠到侏罗纪之间。大地电磁测深和地震剖面解释表明，达拉布特走滑断裂控制了西北缘高角度逆冲断裂的分布与性质。西北缘二维和三维地震剖面解释表明，横向走滑断裂样式为正花状构造或者负花状构造，同时具有向南东或北西方向逆冲和拉伸的特征。横向走滑断裂为西北缘逆冲构造南北方向分段的主要断裂，并控制了西北缘中生代地层的沉积。西北缘构造是形成于主边界断裂的斜向挤压作用，而基底卷入逆冲断裂则属非纯挤压形成的逆冲构造。

Transpression and wrench faults of northwestern margin of Junggar Basin

The Junggar Block collided with the Altaids orogenic belts from the Paleozoic era，resulting in the west Junggar district under oblique compression.Based on field survey，Remote sensing interpreting，updated geological results of magnetotelluric survey and re interpretation of seismic cross sections，the transpression of west Junggar in the Junggar Basin is expressed as west Junggar highly oblique reverse faults and basement involved deformation，the Dalabute sinistral strike slip fault with considerable strike slip components，and as well as second transverse NW directed dextral strike slip faults.The major structural styles of transverse structure is mainly of positive flower structure or negative flower structure，both displays features of southeast directed or northwest directed compression or extension.The transverse structure are major faults which separated the west Junggar thrust and fold belt into several of south north sections，and controlled distributions of the sedimentary facies and thickness of Mesozoic strata in the area.We conclude that the west Junggar highly oblique reverse faults and basement involved deformation is formed by the transpression，not by the pure compression.