南天山晚新生代褶皱冲断带位于南天山南麓,是南天山陆内造山作用过程中,南天山造山楔向塔里木盆地推进的结果。褶皱冲断带的构造变形以挤压冲断构造为主,伴生有挤压走滑构造和盐相关构造。以盖层滑脱冲断为特征,伴生有基底卷入型冲断构造。褶皱冲断带的主滑脱冲断层由造山带向盆地方向逐渐抬升,而且,“厚皮”构造向造山带方向越来越发育,“薄皮”构造向盆地方向越来越发育。整个褶皱冲断带从东到西冲断作用发生的时间基本一致,起始于中新世中-晚期并一直持续到现今;冲断高峰发生于新近纪晚期一第四纪。褶皱冲断带的形成过程为前展式,由南天山向塔里木盆地推进。受地层剖面结构、沉积建造、基底起伏、所处的构造部位等因素控制,南天山褶皱冲断带的构造变形特征沿走向具有明显的分段性,从东到西划分出4个次级褶皱冲断带:库车、乌什、柯坪和喀什北褶皱冲断带。每个次级褶皱冲断带在共性的基础上,都有自己独特的构造变形特点。
The Late Cenozoic South Tianshan fold-thrust belt between the Tarim Basin and South Tianshan Mountains is the result of the Late Cenozoic South Tianshan intracontinental orogeny. It is overthrusting of the South Tianshan orogenic wedge onto the north margin of the Tarim Basin that generated the fold-thrust belt. The deformation in the fold-thrust belt is dominated by over-thrusting, accompanied with compressive strike-slip and salt-related structures. The master detachment-thrust faults are more and more toward the Tarim Basin. The "Thin-skinned" structures also are toward the basin, but "thick-skinned" structures are less and less toward the basin. The thrust process began in the Middle-Late Miocene and lasted to the present. Late Neogene-Quaternary is the peak stage of thrusting. The growth course of the fold-thrust belt is a forward-unrolling type,i, e., advancing from South Tianshan Mountains to the Tarim Basin. Because of differences of stratigraphic sequence, sedimentary formation, basement, and structural location,the fold-thrust belt has obviously a strike segmental character. From east to west, therefore,it can be divided into four segments: Kucha, Wushi, Keping and North Kashi fold thrust sub-belts, from East to West. Every sub-belts have their own features.