阿尔金断裂带中段中生代盆地形成及演化

Formation and Evolution of Cenozoic Basins in the Middle Part of Altyn Tagh Fault Zone

阿尔金断裂带是中国西北地区北东—南西走向的大型转换断裂,在不同时代受区域应力作用的影响,断裂运动的方向不同,断裂带两侧也相应的形成了不同类型的盆地。通过对断裂带两侧的中生界盆地和地面露头分布的研究,应用大量学者对阿尔金断裂带走滑作用研究的认识,结合与右行离散平移断裂有关的构造组合模型,开展了阿尔金断裂带两侧中生界盆地演化过程、盆地类型、沉积环境以及阿尔金断裂带与周缘盆地演化之间的关系。根据阿尔金断裂带两侧中生界盆地露头和盆地形态、岩相之间的契合关系,结合前人研究成果,认为新生代以来阿尔金走滑断裂带左行走滑距离在350km左右;泥饼右行走滑实验模型和阿尔金中段中生代原型盆地之间,在成盆环境和盆地类型上,均具有良好的构造契合关系;阿尔金断裂带走滑复位以后的中生代原型盆地分布研究,对认识现今中生界盆地类型及油气勘探都具有重要意义。

Altyn Tagh fault zone is a large NE-SW trending transforming fault located in the northwestern China.Various basins formed in the both sides of the fault zone due to different regional stress at different times and different fault movement directions.Based on the studies of the Cenozoic basins and surface outcrops in both sides of the fault and previous research results on strike-slipping of the Altyn Tagh fault,the paper analyzes the evolution process,basin type,sedimentary environment and the relationship between the Altyn Tagh fault zone and the evolution of peripheral basins by combining with a structural model related to right-lateral divergent fault.According to the relationships among the outcrop,basin shape and lithofacies of the Cenozoic basin in both sides of the fault zone,it is considered that the left-lateral slipping distance of Altyn Tagh fault is about 350 km since Cenozoic;the comparison of the experimental model of mud cake right-lateral slipping with the Cenozoic prototype basin in the middle part of Altyn Tagh fault zone shows good structural matching relations on the basin forming environment and basin type.The study on the distribution of Cenozoic prototype basins after the restoration of the strike slip of Altyn Tagh fault has important significance for understanding current Cenozoic basins and for petroleum exploration in the basins.