安徽休宁县大丘田金矿床金的赋存状态研究

Study on the occurrence state of gold minerals in Daqiutian gold deposit,Xiuning County of Anhui

大丘田金矿是迄今发现的安徽境内唯一一个处于障公山地体核部受韧性剪切构造带控制的贫硫化物石英岩(脉)型小型矿床。在矿相学观察的基础上,开展了电子显微镜背散射观察(BSE)、能谱分析(EDS)和电子探针(EPMA)测试,以期查明大丘田金矿床中金的赋存状态和分布特征。结果表明,大丘田金矿中金的赋存状态有两种,一是“可见金”形式,主要以显微中细粒自然金或银金矿不均匀分布于黄铁矿、毒砂矿物的裂隙间、颗粒中、颗粒间;另一种是“不可见金”形式,以超显微微粒赋存于黄铁矿、毒砂、方铅矿、黄铜矿等硫化物中。

Daqiutian gold deposit in Xiuning County of Anhui Province is the only small-size and sulfide-poor quartzite(quartz vein)type deposit which is controlled by ductile shear structural zone in the core of the Zhanggongshan terrain.On the basis of mineralogy observation,electron microscope back-scatter observation(BSE),energy spectrum analysis(EDS)and electron microprobe analyses(EPMA)are carried out for the purpose to study the occurrence state and distribution feature of gold in the deposit.The study result shows that there are two kinds of occurrence state of gold in Daqiutian deposit,one type is the form of"visible gold",which mainly consists of microscopic medium and fine grain natural gold and electrum which are distributed unevenly in the cracks and grains of pyrite and arsenopyrite minerals.The other type is the form of"invisible gold",which mainly occurs in the sulfide of pyrite,arsenopyrite,galena and chalcopyrite as ultra-microscopic particles.