桂东大瑶山地区六安金矿床金的赋存状态研究

Occurrence of Gold in the Liuan Gold Deposit in Dayaoshan Area, Eastern Guangxi

桂东大瑶山地区是我国南方重要的黄金生产基地,多期次的构造–岩浆活动,为金及多金属矿化提供了优越的成矿条件。但是,从找矿实践来看,由于成矿理论研究相对滞后和薄弱,以致找矿思路依然局限于“就矿找矿”,虽然陆续发现了200多个金矿床(或矿化点),但总体表现为“只见星星,不见月亮”,找矿成果与该地区超强的金地球化学异常和优越的成矿地质条件严重不匹配。蚀变岩型金矿是大瑶山地区未来重要的矿产勘查类型,但有关该类型金矿的基本成矿特征研究却相对薄弱,鉴于此,本次研究选择六安蚀变岩型金矿为对象,通过详细的野外地质调查,利用显微镜、扫描电镜和电子探针等分析手段,研究矿床基本特征、典型矿石矿物组合和金的赋存状态,以期为后续矿产勘查和资源开发提供必要的依据。研究结果表明,六安金矿主要的围岩蚀变为硅化、黄铁矿化、绢云母化、绿泥石化、褐铁矿化;金的赋存状态主要为包裹金和晶格金,其中包裹金以银金矿的形式赋存于黄铁矿之中,粒度一般为10 μm;晶格金主要以类质同象形式赋存于晶型较完整的黄铁矿之中。

Dayaoshan area in Eastern Guangxi is an important gold production base in southern China. Mul-ti-stage tectonic magmatic activities provide superior metallogenic conditions for gold and poly-metallic mineralization. However, from the perspective of prospecting practice, due to the rela-tively backward and weak research of metallogenic theory, the prospecting idea is still limited to “on-site prospecting”. Although more than 200 gold deposits (or mineralization points) have been found in succession, the overall performance is “only stars, not the moon”. The prospecting results are seriously mismatched with the super strong gold geochemical anomalies and superior metallogenic geological conditions in this area. Altered rock type gold deposit is an important type of mineral exploration in Dayaoshan area in the future, but the research on the basic metallogenic characteristics of this type of gold deposit is relatively weak. In view of this, the altered rock type gold deposit in Liuan is selected as the object of this study. Through detailed field geological survey, the basic characteristics and typical ore deposits of the deposit are studied by means of microscope, scanning electron microscope and electron probe, in order to provide the necessary basis for the follow-up mineral exploration and resource development. The results show that the main wall rock alteration of Liuan gold deposit is silicification, pyritization, sericitization, chloritization and limonitization;the occurrence state of gold is mainly wrapped gold and lattice gold, in which the wrapped gold is hosted in pyrite in the form of silver gold ore, and the grain size is generally 10 μm;the lattice gold is mainly hosted in pyrite with complete crystal form in the form of isomorphism.