中亚及中国西部侏罗纪沉积盆地的构造特征

侏罗纪是中亚和中国西部地区沉积盆地主要形成时期,这表现在两个方面:(1)先期存在的盆地在此阶段沉积范围持续扩大;(2)形成了许多新的侏罗纪沉积盆地.本文通过对劳亚大陆南部侏罗纪特提斯北带构造特征、诸盆地早-中侏罗世岩相古地理和构造样式的分析,表明中国西部与中亚地区在侏罗纪时虽然都处于新特提斯北部被动大陆边缘,但由于受帕米尔弧向北推挤的影响,以及昆仑构造带与塔拉斯-费尔干纳断裂和阿尔金大型走滑断裂的存在,这两个地区的侏罗纪盆地具有完全不同的构造起因.以塔拉斯-费尔干纳断裂为界,西南侧中亚地区的侏罗纪沉积盆地主要是由新特提斯北部大陆边缘的被动伸展形成;东北侧中国西部的侏罗纪沉积盆地则主要发育于区域性挤压构造背景之下,形成的主要机制是重力陷落.此外,沿塔拉斯-费尔干纳断裂还存在几个侏罗纪的走滑拉分盆地.中国西部与中亚地区侏罗纪盆地的不同成因特征对盆地的比较研究和寻找侏罗系烃源岩都具有重要意义.

STRUCTURAL FEATURES OF THE JURASSIC BASINS IN WESTERN CHINA AND MIDDLE ASIA

There developed a lot of sedimentary basins in the western China and the Middle Asia during Jurassic. Based on analysis of tectonic characteristics of the northern belt of the Jurassic Tethys, the petrofacies and paleogeography, and the tectonic styles of the Jurassic sedimentary basins in the western China and the Middle Asia, it can be discovered that these basins have different genesis although the both were situated in the northern passive continental margin. Due to the occurrences of the Kunlun orogenic belt and the strike slippings of the Talas Fergana and the Altun faults, in the south-west side of the Talas Fergana fault, i.e, the Middle Asia, the developing of Jurassic basins resulted from passive extension of the passive continental margin; while in the north east side of the Talas Fergana fault, i.e, the western China, the Jurassic basins were created by the gravitation depression under a background of compressional stress field.