甘肃大水金矿床金的赋存状态和金矿物特征

来源期刊：黄金2011年第8期

论文作者：代文军 雒晓刚 史文全 马小云

文章页码：16 - 21

关键词：金矿物特征； 赋存状态； 大水金矿床； 甘肃

Key words：gold mineral characteristic； occurrence state； Dashui gold deposit； Gansu

摘    要：利用光学显微镜观察和电子探针分析,对大水金矿床金矿物的特征研究表明,矿石中金属矿物主要为黄铁矿、黄铜矿、含铁砷黝铜矿、赤铁矿、褐铁矿、孔雀石、磁黄铁矿和自然金等;非金属矿物主要为玉髓状石英、方解石、白云石、长石和绢云母等。矿石中金矿物以自然金为主,其次是银金矿,自然金颗粒形态较复杂,呈不规则状、长角粒状、板片状、八面体和正方细柱自形晶粒以及凹凸状、浑圆状、麦粒状、角粒状。粒度以细—微粒为主。化学分析表明,w(Au)均在98%以上,其他元素含量甚微,金成色为999.1～999.7。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,在与自然金共生的黄铁矿中,Co、Ni比值大于1,说明成矿物质与深部岩浆作用有关。从围岩和岩浆岩具有较高金的背景值指示成矿元素可能来源于岩浆活动造成的围岩中Au的活化迁移。

Abstract: The study on gold mineral characteristics of Dashui gold deposit is carried out with light microscope observation and electron probing analysis.The results show that the metallic minerals in ore are mainly pyrite,chalcopyrite,tennantite containing iron,hematite,limonite,malachite,pyrrhotite,native gold and ect.the non-metallic minerals are mainly chalcedony-shape quartz,calcite,dolomite,feldspar and sericite.Gold mineral in ore is mainly native gold,whose particle shape is complicated,such as tuberose,siliqua granular,flat bar,octahedral,square thin pillar euhedral crystal,concave-convex,perfect sphericity,kernel and corner shape.The gold particles are mainly micro fine.Chemical analysis shows that the grade of native gold is up to 98% and the quality is between 999.1 and 999.7.The high quality of native gold shows that it formed in the deep.The Co/Ni value in paragenesis pyrite is higher than 1,which demonstrates the ore-forming minerals related to deep magmatism.The high gold background value in the wall rock and magmatic rock indicates that the metallogenic elements might originate from wallrock gold element activation transfer caused by magmatic activity.