内蒙古乌兰浩特地区早白垩世韧性变形对嫩江-八里罕断裂的响应

The response of Early Cretaceous ductile deformation to the Nenjiang-Balihan fault in Ulanhot area,Inner Mongolia

为了探讨嫩江-八里罕断裂带对研究区的影响,对乌兰浩特地区出露的韧性变形带进行野外构造要素测量、对比,初步提出研究区曾经历左旋走滑变形阶段。通过对该韧性剪切带韧性变形特征的研究,明确了剪切带变形程度为初糜棱岩-糜棱岩。结合前人研究成果及相关年代学资料,确定走滑时间为早白垩世中期(139~113Ma),这对进一步明确嫩江-八里罕断裂的展布位置、断裂带的宏观特征及形成时间的讨论具有重要意义。

In order to explore the influence of the Nenjiang-Balihan fault zone in the study area, the authors made field structure elements measurement and comparative study of Ulanhot regional ductile deformation zone and, on such a basis, put forward the argument that the study area is at the sinistral strike-slip deformation stage. Through the study of the toughness deformation characteristics of the ductile shear belt, the deformation stage of shear band is defined as the initial mylonite and mylonite. Based on previous researches and related chronologic data, the authors hold that the slip time was Early Cretaceous （139 -113 Ma）. It is of great significance to further clarify the macroscopic characteristics of the fracture zone and the formation time.