针对塔西南西昆仑山前基底寒武系膏盐层的分布情况,采用物理模拟研究方法,设计了研究基底滑脱层的分布对褶皱冲断带影响的两组实验。实验结果表明:基底滑脱层的分布对构造变形样式的发育及变形前锋的传播有重要的控制作用。具体表现为在基底寒武系膏盐层分布靠近山前的苏盖特地区变形整体表现为滑脱式的宽缓箱状褶皱的发育;寒武系膏盐层分布较远离山前的柯东地区在缺失寒武系膏盐层的山前地区,表现为叠瓦状逆冲断层的发育,形成断层相关的紧闭褶皱,往北有寒武系膏盐层发育的固满地区才发育较大型的箱状背斜。实验过程中苏盖特地区的变形前锋往前陆方向传播得更快更远,而柯东地区变形前锋往前陆方向传播得较慢较近,从而在变形过程中二者的变形前锋容易出现一个“z”字形转折。
This article used an analogue modeling method to study the effect of spatial distribution of basement detachment on deformation in a fold and thrust belt. Based on the spatial distribution of Cambrian salt in West Kunlun fold and thrust belts southwest of Tarim basin, we designed two experiment models. Results show that the spatial distribution of basement detachment plays a very important role in controlling the deformation styles and deformation front of a fold and thrust belt. In the Sugaite area Where the Cambrian salt deposited closely to the West Kunlun Mountain, the deformation mostly emerged in a detachment structure style, mainly developed box-shaped anticline. Comparatively, in the mountain front of Kedong area because the Cambrian salt disappeared, it mostly formed imbricate thrusts and thrusts-related tight folds, to the north in Guman area where exists Cambrian salt and the deformation become a box-shaped anticline way. In the processes of experiments, the deformation front of Sugaite transmitted much faster and over a longer distance toward foreland than Kedong area, thus the thrust front favors a Z-shaped transition.