内蒙古呼伦贝尔伊敏地区构造特征及其演化

Structural Feature and Evolution in the Area of Yimin,Hulun Buir,Inner Mongolia Autonomous Region

根据野外数据资料收集以及前人的研究,对伊敏河五牧场等地区的构造特征以及构造演化过程进行了系统性的总结和分析。按类型划分,研究区构造可分为褶皱、断裂。褶皱构造主要形成于加里东期和华力西期,断裂构造形成时期主要为华力西期,其次为燕山期,以北东向和北西向两组断裂为主。据板块构造理论,研究区大地构造位置位于西伯利亚板块东南边缘,通过出露的各时代地层特点分析,结合内蒙古大地构造单元划分,认为研究区构造演化过程经历了古生代大陆边缘稳定增生、中生代陆内裂陷充填和新生代垂直抬升三个阶段。

This paper systematically summarizes and analyzes structural feature and evolution in the area of Wumuchang,Yiminhe Town on the basis of field data collection and previous studies. The structural feature of this area consists of fold and fracture. The former was mostly formed in Caledonian and Variscan,and the latter was mainly in Variscan and then Yanshanian,based on NW-trend and NE- trend fractures. The geotectonic position lies in the southeast edge of Siberian plate in line with the theory of plate tectonics. This paper concludes that the structural evolution of this area has gone through steady continental margins accretion in Paleozoic,chasmic and sealed intra continental in Mesozoic and vertical transportation in Cenozoic by analyzing exposed formation characteristics of all ages and liking to the division of structural units in Inner Mongolia.