库车坳陷西段的逆冲推覆距离研究

库车坳陷西段地区发育有巨厚膏盐层,喜马拉雅山末期构造运动使天山造山带大幅度向南挤压,造成大量盐体在库车前陆褶皱冲断带前缘被逆冲推覆至地表,地层并发生强烈的褶皱和逆冲推覆,所以在计算该区域地层向南推覆的总距离时,不仅要考虑平衡剖面技术所恢复出地层横剖面上的缩短量,另外还要考虑由于膏盐层塑性流动所造成上盘推覆体向南的滑移距离,本文综合利用平衡剖面技术和物理模拟实验方法求取了该研究区域的地层缩短量(24.5km)及上盘推覆体向南的滑移距离(3.969~14.727km),从而计算出库车坳陷西段的逆冲推覆距离为18.5~39.227km。

Displacement of a Thrust in the Western Kuqa Depression

There is a thick salt layer in the western Kuqa Depression. The tectonic activities during the late Himalayan made the Tianshan orogeny advance southward and the salt body in the front edge of the Kuqa foreland fold-thrust belt emerged to the earth's surface. Tense folding and thrusting happened to the stratum of this place. So, the calculation of the distance that regional geological bodies moved southward should refer not only to the amount calculated from the balanced-section technique, but also the sliding distance of the upper body as a result of the plastic feature of the salt layer. Through both methods of balanced-section technique and physical modeling, the amount of the stratum's shortening (24.5 km) and the southward sliding distance (3.969~14.727 km) of the upper body are worked out, and then we know the displacement of the thrust (18.5~39.227 km) in the western Kuqa Depression.