大尹格庄金矿床黄铁矿原位微区微量元素地球化学特征

Geochemical Characteristics of Trace Elements in the Pyrite In-Situ Micro-Zone of Dayingezhuang Gold Deposit

摘要: 胶东地区是我国最大的金矿集区，其金矿床的大量形成和巨量金的来源一直广受关注。招平断裂带是胶东地区最重要的金成矿带，坐落于招平断裂带中部的大尹格庄金矿床是一个典型的大型的构造蚀变岩型金矿床。根据大量的岩相学观察和野外地质研究，将大尹格庄金矿床中的黄铁矿分为三个阶段(Py1、Py2、Py3)，同时将其与成矿期前胶东群中的黄铁矿(Py0)进行对比。其中三个阶段分别为：(1) 石英–(绢云母)–黄铁矿阶段(Py1)，黄铁矿呈浸染状或团块状分布在绢英岩中，为成矿早期；(2) 石英–多金属硫化物阶段(Py2)，由石英、黄铁矿和多种金属硫化物组成，硫化物主要有黄铜矿、方铅矿、闪锌矿等。含矿热液多沿裂隙充填或者以脉状、网脉状穿插早期的矿脉，为金成矿的主要阶段；(3) 石英–碳酸岩阶段(Py3)，石英–碳酸岩呈细脉状充填在矿体围岩中或者前两个阶段形成的构造角砾岩之间，多分布在断层下盘，主要矿物为石英+碳酸岩+少量黄铁矿，无金矿化。三个阶段的黄铁矿晶格中Au含量普遍较低，大部分低于1 ppm，说明Au主要以可见金的形式存在。Py1和Py3中微量元素总量较少，而主要矿化阶段Py2中微量元素总量远高于其余阶段。Py2中Au和As的含量相对较高，且两者呈良好的正相关关系，表明As的加入对Au的富集起到了重要作用。

Abstract: The Jiaodong area is the largest gold ore concentration area in my country. The formation of a large number of gold deposits and the source of huge amounts of gold have always attracted wide attention. The Zhaoping fault zone is the most important gold metallogenic belt in the Jiaodong area. The Dayingezhuang gold deposit located in the middle of the Zhaoping fault zone is a typical large-scale tectonic altered rock type gold deposit. According to a large number of petrographic observations and field geological studies, the pyrite in the Dayingezhuang gold deposit is divided into three stages (Py1, Py2, Py3), and the pyrite (Py0) in the Jiaodong Group before the mineralization period is for comparison. The three stages are: (1) The quartz-(sericite)-pyrite stage (Py1), where the pyrite is distributed in the sericite in disseminated or clumped form, which is the early stage of mineralization; (2) The quartz-polymetallic sulfide stage (Py2) is composed of quartz, pyrite and various metal sulfides. The sulfides mainly include chalcopyrite, galena, sphalerite, etc. Ore-bearing hydrothermal fluids are mostly filled along cracks or interspersed with early ore veins in the form of veins and veins, which are the main stages of gold mineralization; (3) Quartz-carbonatite stage (Py3), where quartz-carbonate is filled in veins The surrounding rocks of The ore body or between the structural breccias formed in the first two stages are mostly distributed in the footwall of the fault. The main minerals are quartz + carbonate rock + a small amount of pyrite, and there is no gold mineralization. The Au content in the pyrite lattice of the three stages is generally low, most of which are less than 1ppm, indicating that Au mainly exists in the form of visible gold. The total amount of trace elements in Py1 and Py3 is less, while the total amount of trace elements in Py2, the main mineralization stage, is much higher than that in the other stages. The content of Au and As in Py2 is relatively high, and the two have a good positive correlation, indicating that the addition of As plays an important role in the enrichment of Au.