摘要
小秦岭区域复背形南侧的“秦仓沟组”,原定为一套混合岩和混合岩化变质岩,划属太华群的上部组元.近年经研究确认为具典型韧性变形的动力学标志的古老糜棱岩带,是在左行走滑的强烈挤压条件的深层塑性变形产物,从而肯定了太华群南侧也与北侧一样,为古韧性剪切带所围限.结合实际资料提出了对太华群划分方案的意见.太华群边缘韧性剪切带的发现,对小秦岭区域地质构造发展演化的认识具重要意义,开辟了认识区域构造格局和金矿分布规律的新思路.
The Qincangou formation belongs to the Taihua Group in the current division of the strata , This formation occurs in the west plunging crown of the regional composite antiform and it is the successive sedimentation on the Sanguan Myao formation. There is not any different characteristics between the two formations. The Qincangou formation also occurs in the south of the regional composite antiform. And their attitudes are opposite. There is a regional fault between them. These facts are worth thinking about deeply.According to the research done recently, the Qincangou formation in the south which is composed of migmatite and migmatized rock shows some dynamic appearances produced by ductile or plastic deformation. These small-scale structures, which are produced by the strong compression resulting from the regional dex-tral strike-slip, show that the south boundary of the Taihua Group is an old belt of mylonite and is the same as the north. Depending on the regional research, the writers think that it is not right to use the current division about the Taihua Group.The outlying ductile fault that has been found is an important structure for the writers to divide the stages of geological evolution of the lesser Qinling. It will give a new train of thought about the characteristies of the structures and the regional pattern of the gold deposits in the regional bachground.
关键词
太华群
秦仓沟组
剪切带
糜棱岩
Taihua Group
Qincangou formation
Ductile fault
Mylonite
