甘肃省文县阳山超大型金矿床成矿作用及成矿模式

METALLOGENIC PROCESS AND MODEL OF THE SUPER-LARGE YANGSHAN GOLD DEPOSIT IN GANSU PROVINCE

阳山金矿床位于甘肃省文县.区域构造演化分析、成矿年代学研究及野外地质观察表明,矿区岩浆岩与金成矿在空间及时间上均存在密切关系.通过对阳山地区区域地层成矿元素含量及阳山金矿各类矿石元素含量分析,确定泥盆系三河口组地层为阳山金矿床的矿源层.进一步研究矿床稀土元素、稳定同位素、流体包裹体等测定结果,认为阳山金矿成矿物质来源复杂,具地层和岩浆岩双重来源;成矿热液具有岩浆热液、变质热液以及大气降水多种来源.自三叠纪以来,与区域构造演化有关的多次岩浆热液活动与阳山金矿成矿作用存在密切相关.综合分析认为,阳山金矿床成矿作用是多期岩浆热液活动叠加的复合成矿作用.在此基础上提出了阳山金矿床的成矿模式.

The Yangshan gold deposit is located in Wenxian, Gansu Province. Research on regional tectonic evolution and mineralizing chronology combined with field observation shows that there is a close spatial and temporal relationship between magmatic rocks and gold mineralization. The element content analysis of regional strata and gold ore confirms that the source bed of Yangshan gold deposit is Devonian Sanhekou formation. Further analysis on REE, stable isotope and fluid inclusion indicates that the sources of ore-forming substance of Yangshan gold deposit are complicated, with characters of both stratum and magmatite origin. The mineralizing fluid includes magrnatic hydrothermal fluid, underground thermal brine, metamorphic hydrothermal fluid, atmospheric water and so on. Since Triassic period, several magmatic hydrothermal activities, which related to the regional tectonic evolution, have close relations with the gold mineralization of Yangshan gold deposit. It is concluded that Yangshan gold deposit underwent a complex mineralizing process of thermal brine mineralization and abyssal fluid mineralization. A mineralizing model of Yangshan gold deposit is therefore established on this basis.