阿姆河右岸区域构造大剖面解析及成因探讨

阿姆河盆地右岸区块地理位置位于土库曼斯坦的阿姆河流域北侧至土库曼斯坦—乌兹别克斯坦国境线南侧之间,西南紧邻吉萨尔山脉,是中石油重要的海外油气勘探开发基地。开展其构造特征解析和成因机制探讨,对研究含盐盆地分层构造变形特征和促进能源勘探开发均具有重要意义。以构造建模和构造复原理论为指导,精细解释过阿姆河右岸区块的东西向地震大剖面,分析其地质结构特征和形成演化过程。结果表明：阿姆河右岸区块纵向上发育前二叠系基底和二叠系—第四系沉积盖层。以上侏罗统基末利—提塘阶膏盐岩为界,盐上和盐下构造形态具分层变形特征;盐上多发育陡窄的滑脱褶皱,断裂以倾向NW的小断距正断层和走滑断层为主;盐下多发育宽缓的冲断褶皱,断裂以倾向SE的大断距逆断层为主。受基底构造楔楔入影响,研究区自西向东构造抬升和挤压幅度逐渐增大。根据平衡剖面复原并结合区域地质背景,将研究区构造演化划分为前二叠纪基底形成期、二叠—三叠纪弧后裂谷期、侏罗—古近纪稳定沉积期和新近纪以来挤压抬升期共4期构造演化阶段。新生代多方向构造叠加影响、基底构造楔活动和膏盐岩对分层构造变形的调节作用是阿姆河盆地右岸地区纵向分层、横向分带构造特征的主要控制因素。

Analysis of structural cross section of the Amu Darya Right Bank and discussion on causes

Amu Darya Right Bank is located between the north of the Amu Darya River in Turkmenistan and the south of the border line between Turkmenistan and Uzbekistan, and is adjacent to the Gisar Mountains in the southwest. It is an important overseas oil and gas exploration and development base of CNPC. The analysis of its structural characteristics and discussion of its genetic mechanism are of great significance to the study of layered structural deformation characteristics of salt bearing basins and the promotion of energy exploration and development. Guided by the theory of structural modeling and structural restoration, the east-west seismic profile of the Amu Darya Right Bank has been interpreted in detail, and its geological structure characteristics and formation and evolution process have been analyzed. The results show that the Amu Darya Right Bank is vertically developed with pre-Permian basement and Permian-Quaternary sedimentary cover. The Upper Jurassic Jimuli-Titang stage gypsum salt rock is the boundary, and the supra salt and sub salt structures are characterized by layered deformation; steep and narrow detachment folds are mostly developed on the salt, and the faults are mainly small offset normal faults and strike-slip faults inclined to the northwest. Wide and gentle thrust folds are mostly developed under salt, and the faults are mainly large fault displacement reverse faults inclined to the southeast. Affected by the wedge of basement structure, the tectonic uplift and compression amplitude in the study area gradually increase from west to east. According to the restoration of balanced profile and the regional geological background, the tectonic evolution of the study area is divided into four tectonic evolution stages: pre-Permian basement formation stage, Permian-Triassic back arc rift stage, Jurassic-Paleogene stable sedimentation stage and Neogene compression uplift stage. The influence of Cenozoic multi-directional tectonic superimposition, basement tectonic wedge activity and the adjustment of gypsum salt rock on layered tectonic deformation are the main controlling factors for the structural characteristics of vertical stratification and horizontal zoning in the Amu Darya Right Bank.