【摘要】 笔者利用库车秋里塔格地区3000km的二维地震反射资料,结合地表构造测量成果,分段叙述秋里塔格褶皱带的构造几何学和运动学性质,说明构造交汇部位断层和褶皱的叠加过渡关系,并通过二维构造剖面的组合,建立秋里塔格褶皱带的三维构造几何模型。研究发现秋里塔格褶皱带为浅部断层传播褶皱与深部断层转折褶皱叠加形成的复合型背斜带,深部台阶状逆断层的叠加作用、叠加断层位移量的转换、断层断坡高度的变化造成地表背斜沿走向发生变化,笔者通过测量断层叠加方式、断层位移量转换、断层断坡高度,说明秋里塔格褶皱带背斜叠加、扭曲、分叉现象的构造机理,并且给出了秋里塔格褶皱带断层的滑移量。更多还原

【Abstract】 The south margin of the Tianshan Mountains has undergone multiple phases of compressional deformation since the Oilgocene and Pleistocene. This deformation created the EW-striking Qiulitag anticline zone, 300 km long and 15 - 20 km wide, which is part of the Kuqa thrust-and-fold belt along the southern piedmont of the Tianshan Mountains. This paper presents a detailed description and analysis of a 3-D geometrical and kinematical model of the Qiulitag anticline zone. Over 3000 km-long 2-D seismic refection profiles, five exploratory wells and 1: 100000 scale geological mapping were used in the analysis. Two different thrust systems characterized by southward tectonic transport were found: an upper imbricate fault zone, which deforms Cenozoic strata with fault-propagation folds in the hanging wall, and a duplex structure of fault-bend-folds and fault ramps composed of Jurassic, Cretaceous and Paleogene rocks. The shallow folds of the Qiulitag anticline zone are tight and asymmetric, while the core of the Qiulitag anticline may be disharmonically folded at the level of Plaeogene shale and gypsum. The restoring balanced cross sections suggest that the minimum shortening of the deep fault system in the Qiulitag anticline zone is more than 10 km and decreases eastwards and westwards along its strike. The ramp height of the deep fault system is 3 km in the east regional cross section (where a sole thrust fault is developed) and declines westwards by 1 km to somewhere an imbricate fault is developed.更多还原