内蒙古塔尔气地区构造特征研究

Research on structural characteristics in Taerqi area,Inner Mongolia

笔者在1∶5万区域地质调查的基础上,对塔尔气地区发育的构造形迹进行了较为详细的研究。结果表明:塔尔气地区可划分五个构造层,分别是兴凯期构造层、早加里东期构造层、海西期构造层、燕山期构造层和喜山期构造层。根据构造形迹中面状构造、线状构造及组合特征以及其所显示的动力学标志,对各构造层的局部应力场进行了恢复。其中,兴凯期早期为NE—SW挤压(左行)剪切作用,后期为近SN向挤压;早加里东期应力作用方式应为NW—SE向挤压为主;海西期主要为近SN向挤压作用;燕山期同样为近SN向挤压作用;而喜山期则表现为大规模的差异性升降运动。

Based on the 1：50 000 regional geological survey, the authors studied the structural features of Taerqi area. The results showed that Taerqi area can be divided into five structural layers, which are Xingkai struc- tural layer, Early Caledonian structural layer, Hercynian structural layer, Yanshanian structural layer and Himalay- an structural layer, respectively. According to the planar structure, linear structure, combination feature and their dynamics symbols, the authors restored the local stress fields of each structural layer. The early Xingkai period was controlled by the NE -SW extrusion （left） shearing action, and late by nearly NS extrusion; the Early Caledonian period was given priority to NW-SE extrusion; Hercynian mainly by nearly NS extrusion; Yanshanian was also controlled by nearly NS extrusion; Himalayan shows the massive difference lifting movement.