摘要
通过光学显微镜观察、X射线衍射和电子探针分析，对海南乐东抱伦金矿金矿物的特征进行研究，结果表明：矿石中主要金属矿物为黄铁矿和磁黄铁矿，其次为黄铜矿、闪锌矿、毒砂、和方铅矿等；而脉石矿物则主要为石英、白云母和绢云母，其次为方解石、绿泥石和伊利石等。矿石中的金主要以自然金矿物形式产出，颗粒大小在1μm～35μm之间，多呈孤岛状及其他不规则形状，充填在石英以及黄铁矿等硫化物矿物颗粒之间，少量以包裹体形式包裹在硫化物、石英矿物晶体之中。金矿物化学组成分析结果表明，金的质量分数均在92％以上，其他元素含量甚微，其成色在942～978之间。根据自然金矿物的高成色特征可以推断，金矿物形成于较深的部位。此外，在与自然金矿物共生的黄铁矿中，含有较高的微量元素Co和Ni，且Co／Ni比值多大于1，说明成矿物质与深部岩浆作用有关。成矿物质与硫化物、二氧化硅等一同向上运移，当流体物理化学条件（如温度、压力）发生变化时而沉积富集，石英的结晶稍早于硫化物矿物，而硫化物矿物与金矿物的结晶基本上是同时的。
Mineralogical characteristics of gold in the Baolun gold deposit were investigated by using optical microscopy, X-ray diffraction （XRD） and electron probe microanalysis （EPMA） methods. The results showed that metal minerals in the ore were mainly pyrite and pyrrhotite, with minor amounts of chalcopyrite, sphalerite,arsenopyrite and galenite, while non-metal minerals were mainly quartz, calcite, and clay minerals. Gold occurred mainly as native gold, with a particle size ranging from 1 μm to 35 μm,and mainly in island-like, fine granular, and other irregular outlines. Gold particles filled in the interstitial spaces among pyrite, quartz, and other sulfide particles, or were enclosed within the crystals of sulfides and quartz. Chemical composition analysis of gold-bearing minerals by EPMA showed that the gold-bearing minerals contained more than 92 percent Au,with a fineness ranging from 942 to 978. The distinct high fineness of the Baolin gold suggested that the gold-bearing minerals deposited in deep position with high temperature conditions. In addition,the associated pyrite had the Co/Ni ratio〉1,suggesting that the gold mineralized fluid was genetically related to the magmatism in the area. Au migrated upward with sulfides and SiO2, and deposited and concentrated when the chemical-physical conditions of the fluids changed rapidly. Quartz crystallized prior to sulfides,while Au deposited simultaneously with sulfides.
出处
《矿物岩石》
CAS
CSCD
北大核心
2009年第2期31-37,共7页
Mineralogy and Petrology
基金
国家自然科学基金项目(40872038)
关键词
金矿物
硫化物
成色
电子探针
抱伦
gold-bearing mineral
sulfides
fineness
EPMA
Baolun
