天山南麓库车晚新生代褶皱-冲断带

库车褶皱冲断带位于天山南麓,由近东西走向的多条构造带组成。三叠系暗色泥岩、侏罗系煤层、古近系库姆格列木组膏盐层和新近系吉迪克组膏盐层构成库车褶皱冲断带的区域性主滑脱面。褶皱冲断带底面由北向南逐渐抬高。褶皱冲断带主体发育盖层滑脱-冲断构造(薄皮构造),基底卷入型冲断构造(厚皮构造)见于北缘的根带。新生界膏盐层之上构造变形以滑脱褶皱为特色,之下以冲断构造为特色。库车褶皱冲断带是印度-亚洲碰撞远程效应下,(南)天山晚新生代造山过程的产物。褶皱冲断带构造变形的动力来源主要是造山楔向塔里木盆地推进所形成的挤压构造应力。褶皱冲断带构造变形的起始时间为约23Ma,构造变形具有阶段式加速的特点,已经识别出约23Ma、约10Ma、5~2Ma和1~0Ma共4个变形加速期。褶皱冲断带的演化过程为前展式,褶皱冲断带前锋向南推进的同时,后缘持续变形。

Kuqa Late Cenozoic fold-thrust belt in the southern flank of Tianshan Mountains.

Kuqa Late Cenozoic fold-thrust belt in the southern flank of Tianshan Mountains comprises of several structural zones trending E-W. Regional decollement faults are developed in the Triassic dark mudstone, Jurassic coal-bed Paleogene Kumugeliemu gypsum-salt and Neogene Jidike gypsum-salt. The bottom main decollement fault of the fold-thrust belt rises step by step southward. Cover decollement-thrust(thin skinned structure) developed in the major part of the belt, and basement-involved thrusts(thick skinned structure) can only be seen in the root zone at the north margin of the belt. The deformation above the Cenozoic gypsum-salt is characterized with decollement fold and that under the Cenozoic gypsum-salt is characterized with thrust. Kuqa fold-thrust belt was resulted after the Cenozoic(South) Tianshan Mountain building under the far-field effect of the India-Asia collision. The main force resource of the folding and thrusting is the compressive structural force induced by the southward propagation of the(South) Tianshan orogenic wedge. The folding and thrusting began since ca. 23Ma, and then accelerated at ca. 10Ma, 5~2Ma and 1~0Ma. The evolution of Kuqa fold-thrust belt is in the way of forward propagation. While the front of the belt propagates southward, the hinter parts continue folding and thrusting.