广西龙胜大地金矿矿物特征及金赋存状态

Mineralogy and Au Occurrence of the Dadi Au Deposit in Longsheng, Guangxi

广西龙胜大地金矿是桂北地区的剪切带型金矿床，具有石英脉型和构造蚀变岩型两种矿石类型。通过该矿矿物组成和金赋存状态研究，初步查明两种类型的矿石具有相同的矿物组合特征，但石英脉型金矿石中的金矿物主要以自然金的形式赋存于石英脉中，少量赋存于黄铁矿和毒砂中。构造蚀变岩型矿石中金矿物主要赋存于黄铁矿及少量毒砂中。两种矿石的金均以自然金为主，少量为银金矿，颗粒一般小于100μm，大部分为20--50μm。

The Dadi gold deposit in Longsheng, Guangxi is a shear zone type one. It may be divided into quartz vein type and structural altered rock type. Research on the mineralogy and Au occurrence shows that the two types have the same mineral assemblages. The main ore minerals are natural gold, pyrite, pyrrhotite, arsenopyrite, etc. And the main gangue minerals are quartz, calcite, sericite, etc. The gold of the quartz vein type ore occurs as natural gold in quartz vein, and a small amount in pyrite and arsenopyrite. The gold of structural altered rock type ore occurs mainly in pyrite and a small amount in arsenopyrite. Gold in the two kinds of ores exits as native gold, accounting for more than 98% of the total with grain size of less than 100μm, mostly 20-50μm.