阴山造山带—鄂尔多斯盆地岩石圈层、块速度结构与深层动力过程

阴山造山带位于鄂尔多斯盆地的北缘，这一地带不仅是构造活动强、弱的变异地域，且为盆、山的耦合地带，故在造山带与盆地地域具有各异的深层动力过程.本文基于高精度人工源地震宽角反射、折射探测和高分辨率的数据采集，通过反演求得了满都拉—鄂尔多斯—榆林—延川长达650 km剖面辖区的岩石圈精细层、块结构.研究结果表明：①沿该剖面由南向北地壳厚度为40~45 km；在不同构造单元其介质、结构均不相同；速度分布、空间结构形态和界面起伏及属性亦存在着明显差异；上地幔顶部速度为8.0~8.1 km/s；②沿剖面存在5条深、大断裂，且将该区切割成为壳、幔结构明显差异的4个构造单元，即鄂尔多斯盆地、盆山耦合地带、阴山造山带、内蒙构造带，它们各自具有固有的深层过程和动力学响应.同时厘定了阴山造山带与内蒙构造带之间的白云鄂博深、大断裂带是古亚洲洋的南界.在这里不仅导致了阴山造山带的形成，而且聚集了诸多的金属矿产资源，地震亦频繁活动.基于上述研究表明，阴山造山带—鄂尔多斯盆地耦合地带的壳、幔结构复杂、呈现出速度结构各异的层、块状展布.显然，在这一错综的成山、成盆、成岩、成矿和成灾地带，有着特异的深层过程和动力机制.

Velocity structure of layered block and deep dynamic process in the lithosphere beneath the Yinshan orogenic belt and Ordos Basin

The Yinshan orogenic Belt in the northern margin of Ordos Basin is not only a transition region between strong and weak tectonic activities, but also a basin/mountain coupling zone, so there are different deep dynamical processes in the orogenic belt and basin region. Based on the high resolution data from a wide-angle reflection and refraction seismic sounding, we get the fine lithospheric structure along the profile of Mandula-Ordos-Yulin-Yanehuan as long as 650 km. Some results are summarized as follows: 1. The crust thickness is about 40 to 45 km from south to north in the profile. The property of medium and structure are different in different tectonic units. Obvious differences exist in the velocity distribution, structure pattern, and interface undulation and attributes. The velocity is 8.0～8.1 km/s on the top layer of the upper mantle. 2. There are five deep and big faults in the profile, dividing the region into four tectonic units with obviously different crust-mantle structure beneath the Ordos Basin, the basinmountain coupling belt, Yinshan orogenic belt, and Inner Mongolia tectonic area, which have respectively inherent deep processes and dynamic responses. Furthermore, we define the Bayan Obo fault between Yinshan and Inner Mongolia as the south boundary of Paleo-Asian Ocean.Subsequently, Yinshan orogenic belt and a good many metallic mineral resources were formed and frequent earthquakes happened. Therefore, the structure of the crust and mantle in this coupling region is quite complicated, and is divided into layers and blocks. Obviously, in the forming of mountains, basins, rocks, minerals and disasters, there are special deep process and dynamic mechanism.