论文部分内容阅读
本区火山活动极为频繁、分布广。西起永登中堡,经石青洞、二道湾,东至白银区,断续出露长百余公里,东宽西窄。白银一带所发育的火山岩属细碧角斑岩系一岩性分异剧烈、复杂、变质较深、相变大。加之,多期构造变动,片理极其发育。在缺乏标志层的情况下,往往造成查明地层层序的困难。这就是对有关地区构造轮廓各说纷云的基本原因所在。通过野外生产实践,笔者深深地体会到在变质火山岩地区往往难以根据地层资料去查明构造。相反,从构造入手来了解变质火山岩之间的空间相互关系已成为本区确定地层层序的主要途径,这对于正确认识某些矿床的展布规律,具有现实意义。本文拟就公司石灰厂一带构造形态,略谈白银地区广布的火山岩地层的一些基本构造特征。
Volcanic activity in this area is extremely frequent and widely distributed. From Yongdeon Fort in the west, the stone green hole, Erdaowan, east to the silver area, intermittent exposure of more than 100 kilometers, east wide and narrow. The volcanic rocks belonging to the area of Baiyin area belong to the Xipeijiao porphyry. The lithology of rocks is very different and complicated, and the metamorphism is deeper and the phase change is larger. In addition, structural changes in many phases, the film is extremely developed. In the absence of sign layers, difficulties in identifying sequence of stratigraphy often result. This is the basic reason why various contours of the tectonic frameworks in the relevant areas have been mixed up. Through the practice of field production, I deeply understand that in the metamorphic volcanic area it is often difficult to ascertain the structure based on the stratigraphic data. On the contrary, understanding the spatial relationship between metamorphic volcanic rocks from the perspective of structure has become the main way to determine stratigraphic sequence in this area, which is of practical significance for correctly understanding the distribution rules of some mineral deposits. In this paper, we will construct the limestone structure of the Company and briefly discuss some basic tectonic features of widely distributed volcanic strata in the silver area.