We present a new analogue model of oroclinal buckling, which is based on recent advances in our geological understanding of the Mongolian orocline in the Central Asian Orogenic Belt. The model simulates an amplification of a preexisting, gently arcuated accretionary system. In the analogue models, we established three neighboring subdomains that represent contrasting lithospheric domains separated by a steep “subduction” interface. The shortening of the model is parallel to the pseudo-linear interface between these subdomains and produces two different deformation patterns in the amplified interlimb areas of the orocline. We used analogue modelling techniques to investigate both the flow of a ductile lithosphere and the brittle deformation of an upper crust that is associated with the development of an orocline. The modelling results show that: (1) two types of regional-scale folds develop both of which are upright. The largest are steeply plunging oroclines and the smaller have sub-horizontal axes; (2) the overall deformation distribution displays significant thickening/thinning and exhumation of the lower ductile layers with variations of upward transfer of crustal material; (3) the hinge regions of the two adjacent oroclines studied consist of different materials, one contains oceanic and the other felsic lower crustal rocks. It is found that the geometry of the lithosphere beneath the two regions is very different; (4) the geometry of the orocline is non-cylindrical and exhibits an increasing plunge of fold axes when traced from the upper-crust to deeper lithospheric layers. The resulting model is used to geophysically constrain deep crustal structures and surface deformation patterns in Mongolia.

我们基于中亚造山带对蒙古Orocline的地质认识的最新进展，提出了一种新的Oroclinal屈曲模拟模型。该模型模拟了先前存在的，缓和弧形的增生系统的放大。在模拟模型中，我们建立了三个相邻的子域，它们代表由陡峭的“俯冲”界面分隔的对比岩石圈域。模型的缩短与这些子域之间的伪线性界面平行，并在Orocline的放大的中间区域产生两个不同的变形模式。我们使用模拟建模技术来研究韧性岩石圈的流动和与Orocline的发展有关的上地壳的脆性变形。建模结果表明：（1）两种类型的区域性褶皱都发育成直立的。最大的是陡峭下降的Oroclines，较小的是近水平轴。（2）总体形变分布显示出下部韧性层的明显增厚/变薄和发掘，并且地壳物质向上转移。（3）研究的两个相邻Oroclines的铰链区域由不同的材料组成，一个包含海洋，另一个包含长英质下地壳岩石。发现这两个区域下面的岩石圈的几何形状是非常不同的。（4）Orocline的几何形状是非圆柱形的，当从上地壳到较深的岩石圈层追踪时，折叠轴的倾角增加。