喀什凹陷新生代对称型前陆盆地分析

Analysis of Cenozoic Symmetrical Foreland Basin of Kashi Depression

高鸿斌

Gao Hongbin

中原石油勘探局井下特种作业处

Downhole Special Service Company , Zhongyuan Petroleum Exploration Bureau ,Henan 457061 , P. R. China

新生代期间,喀什凹陷内部的沉积为典型的陆相沉积,特别是阿图什组和西域组巨厚的砂砾岩,表现出典型的前陆盆地内部磨拉石沉积特征;而沉降特征则是以腹部略大,山前带相对较小;在构造上,凹陷北部的南天山山前可划分出3 排逆冲褶皱带,南部的西昆仑山山前带可划分出峰带、中带和南带3 部分;通过凹陷内部沉积、沉降及山前构造带构造特征的分析,推测喀什凹陷前陆性质的盆地类型是其南北两侧南天山山前冲断褶皱带和西昆仑走滑挤压冲断褶皱系综合作用的结果。

The internal sedimentation of Kashi depression is typical terrestrial formation , while the thick glutenite bed of Artushi and Xiyu formation were characterized as internal foreland molasse deposition during Cenozoic era. The subsidence rate was larger in internal than that in piedmont belt of this depression. For the depression structure , the Nan-tianshan piedmont in the north of Kashi depression can be divided into three thrust-fold- belt s ,while in the south of the depression , the Xikunlun piedmont can be divided into peak ,middle and south belt s. By analyzing the internal deposition , subsidence and piedmont structure of this depression , the author inferred that the formation of Kashi foreland depression was result of combination effect s of Nan-tianshan thrust-fold belts and Xikunlun slip thrust-fold- belt s in both south and north sides of the depression.