赤峰西部地区金矿床成矿时代及其成矿机制的新认识

A New Viewpoint on the Metallogenetic Epoch and Metallogenic Mechanism of the Gold Deposits in Western Chifeng Area

赤峰西部地区位于华北板块与兴蒙造山带拼合部位南侧的板块北部边缘带上，为著名的赤峰-朝阳金矿集中区重要金矿产地之一。本区金矿床包括两种类型：柴胡栏子金矿床为蚀变岩型金矿；莲花山和红花沟金矿床属石英脉型。诸多地质事实表明这些矿床的形成均与中基性岩浆活动密切相关。野外观察和同位素年代学资料说明中基性岩浆活动发生在印支期。因此，笔者提出本区金成矿时代为印支期的新认识，否定了以往一些研究者提出本区金成矿作用是发生在燕山期或海西期的看法。同时，在综合分析基础上，提出本区金矿床是在印支期构造-岩浆活动作用下、区域隆起的过程中形成的产物，从而对本区金矿床的形成机制做出了新的解释。

Located in the northern margin of the North China plate where this plate was collided with Xing-Meng orogenic belt, the Western Chifeng area is one of the important gold-producing areas in the well-known Chifeng-Chaoyang gold-concentrated region. There are two types of gold deposits in this area, namely altered rock type and quartz vein type. The Chaihulanzi gold deposit belongs to the former type, whereas the Liahuashan and Honghuagou gold deposits are of the latter type. Much geological evidence indicates that the formation of the gold deposits was closely related to the basic-intermadiate magmatic activities which, according to field investigation and isotopic data, took place in Indosinian. The metallogenic epoch is hence thought to be Indosinian instead of being Yanshanian or Hercynian as suggested by previous researchers. Based on an integrated analysis, the authors hold that the gold deposits in the area are products of structural-magmatic activities in Indosinian when regional upheaval occurred. This point of view can better explain the metallogenetic mechanism of the gold deposits in this area.