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金在地壳中平均含量很低,为(5ppb),比地球总平均量(800ppb)低得多,这是因金的化学性质及重力沉积所引起的。在找金矿中有必要认识到金的亲铁性及亲硫性,对金在地壳中富集的作用,在不同环境条件下金主要以不同的稳定水溶性络合物形式迁移,例如在:①高温变质作用下形成的酸性氧化环境中金的Cl~-,Br~-配位体形成的络合离子很稳定,金以卤素元素为配位体形成络离子并以此方式迁移;②在高温作用下形成的高变质带富含硫和碱性金属离子。变质热液中Au以[Au(HS),]~-,[AuS_3]~(3-),等络离子及与NH_3形成络离子等形式迁移等等,笔者从这些络合物的稳定性分析出发讨论了络合物分解沉积成矿的不同条件指出:黄铁矿中含钾高有利于金的富集;矿液中S/As比值越小越有利子金矿生成,Bi,Sb,Te的富集也有利于形成高品位的金矿,以及Te,Mn,Pb,Sr,S,Ni,Co,W,Mo及卤素元素等的富化是金成矿的前兆等等。
The average gold content in the crust is very low (5 ppb), much lower than the global average (800 ppb) due to the chemical nature of gold and the gravitational sedimentation. In looking for gold, it is necessary to recognize the pro-iron and sulfur-binding properties of gold, which have the effect of gold enrichment in the crust. Under different environmental conditions, gold mainly migrates with different stable water-soluble complexes, for example, : ① The complex ions formed by the Cl ~ -, Br ~ - ligands of gold are stable under the acidic oxidation environment formed by the high temperature metamorphism. The gold forms the complex ions by the halogen element ligands and migrates in this way. The metamorphic zone formed at high temperatures is rich in sulfur and alkaline metal ions. In the metamorphic hydrothermal solution, Au migrates in the form of [Au (HS),] ~ ~, [AuS_3] ~ (3-), isoquadron and form complex ions with NH_3 etc. The stability of these complexes The different conditions for the decomposition and sedimentary metallogenesis of the complex are discussed. It is pointed out that the high potassium content in pyrite facilitates the enrichment of gold. The smaller the S / As ratio, Enrichment is also conducive to the formation of high-grade gold ore, and the enrichment of Te, Mn, Pb, Sr, S, Ni, Co, W, Mo and halogen elements is a precursor of gold mineralization.