漠滨金矿成矿物理化学条件的水-岩反应实验研究

Physical-Chemical Conditions for Mobilization of Gold in the Mobin Gold Deposit, Southwest Hunan

以漠滨金矿围岩地球化学特征和矿物流体包裹体组成为基础 ,模拟特定体系水 岩相互作用实验 ,研究结果表明 ,漠滨金矿的成矿元素Au主要源于赋矿围岩———板溪群五强溪组一套浅变质碎屑砂岩、砂质板岩和凝灰质板岩。Cl-在中低温热液体系中能与Au形成稳定络合物的形式进行运移 ,因此Cl-在该区Au成矿过程中起着相当重要的作用。成矿热液流体中Au主要以金硫、金氯络合物形式在溶液中迁移 ,阴离子ΣS、Cl-对金的活化、迁移及沉淀起主导作用。溶液中硫氯离子浓度、溶液酸碱度及反应温度是金活化、迁移及沉淀的决定性因素。

Water-rock experiments were carried out on samples of wall rock from the Mobin gold deposit, southwest Hunan, with the aim of determining the optimum physical and chemical conditions for the mobilization of gold in solution. The results indicate that gold is most easily mobilized from the tuffaceous slate in the Mobin deposit. Mobilization is optimized if fluids are neutral to slightly alkaline and contain both chlorine and sulphur ions at the concentration and composition of about 0.25 mol/L (NH 4) 2S + 1 mol/L NaCl.The amount of gold leached from the tuffaceous slate increases with temperature, although the effect decreases above some 200 ℃.