中亚地区阿姆河盆地查尔朱、布哈拉阶地构造特征及演化

阿姆河盆地是中亚地区重要的含油气盆地,位于阿姆河北岸的查尔朱阶地和布哈拉阶地为盆地的二级构造单元,其油气资源量占全盆地的一半。油气主要富集于阶地的局部背斜构造和生物礁圈闭中,这些圈闭与该区构造形成演化密不可分。利用常规地质资料,通过精细地层对比和地震资料解释,识别出两个关键界面:侏罗纪末的断拗转换面和早第三纪末的区域角度不整合面,并结合板块构造理论确定了构造变形时期。研究认为,侏罗纪以来两阶地经历了侏罗纪—白垩纪断陷—拗陷期和早第三纪抬升—改造期两个重要演化阶段,形成了上、中、下三大构造层。断陷—拗陷阶段的沉积控制了该区的构造格局;中构造层膏盐层的发育丰富了后期的构造样式。早第三纪—晚第三纪的构造运动使该区构造发生了强烈变革,形成了典型的逆断裂、走滑断裂带和不对称复合背斜构造带。

Structural Characteristics and Evolution of Chardzhou and Bukhara Terraces in Amu-Darya Basin, Middle Asia

Amu-Darya Basin is one of the significant large potential petroliferous basins in Middle Asia. Both Chardzhou and Bukhara terraces,which are located in the northeastern of Amu-Darya Basin,provide more than a half of petroleum resources volume of the basin. Rich hydrocarbon is accumulated dominantly in local anticlines and reef traps,which are closely relative with structural formation and evolution in this basin. On the basis on available geological data,fine stratigraphic correlation and seismic data interpretation,two key geological interfaces,the faulting-depression transform interface at the end of Jurassic and the regional angular unconformity at the end of Paleogene,are recognized and the relative deformation phases are defined according to the theory of plate tectonics. It is suggested that the important stages of Jurassic-Cretaceous faulted depression and Paleogene compressed uplifting-reformation have undergone within these terraces,which results in forming the upper,the middle and the lower synthems. The sedimentation in the faulted depression stage controlled the tectonic framework of this region and the development of the salt layers in the middle synthem advanced the succeeding tectonic patterns. Tectonic movements during Paleogene-Neogene time brought on extensive structure deformation in this region,which con-structs a series of typical structural belts such as thrust belts,strike-slip fault belts and asymmetrical composite anticline belts.