内蒙古盘羊山逆冲推覆构造系统的组合特征

Combinational Characteristics of The Thrust Nappe Structure in the Panyangshan,Inner Mongolia

通过1/25万四子王旗幅的野外地质填图,在蒙古寺-盘羊山-乌兰合雅一线存在古生代末大型逆冲推覆构造系统,新太古代色尔腾山岩群和新太古代花岗岩自北向南被逆冲推覆于震旦系什那干组灰岩和古生代碎屑岩之上,并形成大小规模的飞来峰和构造窗。整个推覆系统由顶板逆冲断层与底板逆冲断层及夹于其中的一套叠瓦式逆冲断层和断层夹块组合而成,构成典型的双重逆冲推覆构造系统(Duplex)。该逆冲推覆构造总体逆冲方向指向南南西向,形成时代为二叠纪末,估算推覆距离应大于7.1 km。此逆冲推覆构造与华北板块与西伯利亚板块在二叠纪末陆内碰撞造山有关,是华北板块北缘造山带的重要组成部分。

On the basis of regional investigation（1：250 000） and field geological mapping in Siziwang Qi.We reached such conclusion that there is a huge thrust nappe belt along the Mongolia Temple-Mount Panyangshan-Ulanheya.The Seertengshan Group and Upper Archaean granitoid were thrusted onto the Sinian limestone and Paleozoic clastic rock.The thrust nappe belt is actually a typical duplex,and it is consisted of plentiful structural styles： such as klippes,tectonic windows,roof thrust,floor thrust and horses etc.Moreover,the detailed analysis of the thrust nappe structure indicates that the thrust direction is south and southwest.The events occurred in Late Permian.The nappe displacement is estimated more than 7.1 kilometers.We considered that the thrust nappe belt was from the collisional orogeny of the North China Plate and the Siberian in late Permian,and it is a part of the northern margin of the North China Plate.