热液矿床中锌的迁移、沉淀机制综述  

Mechanisms of Zinc Transport and Deposition in Hydrothermal Deposits

作　　者：陈贤[1,2] 刘家军[1,2] 张德会[1,2] 陶银龙[1,2] 

机构地区：[1]地质过程与矿产资源国家重点实验室,北京100083 [2]中国地质大学地球科学与资源学院,北京100083

出　　处：《高校地质学报》2014年第3期388-406,共19页Geological Journal of China Universities

基　　金：国家自然科学基金(40973035)

摘　　要：硅酸盐熔体体系中,锌主要赋存于熔体相,部分以类质同象的形式进入铁、镁硅酸盐及铁的氧化物中;流体/熔体相分离时,锌优先进入流体相;卤水/气相分离时,锌优先进入卤水相;成矿过程中,锌主要进入液相流体中迁移。在热液环境下,ZnCl2-nn(0≤n≤4)络合物是迁移锌的最重要形式,其次游离Zn2+,Zn2+-SO2-4络合物,Zn2+OH-络合物,在一定条件下对锌的运移也非常重要,但能与锌络合的其它潜在无机配体,如HS-,CO32-,NH3,F-,Br-,S2-x及S2O2-3等,则意义不大。富有机质低温(<200℃)条件下,部分有机质对锌的迁移也具有重要作用,如,羧酸、氨基酸及腐殖酸,其中羧酸意义最大。在Zn成矿过程中,岩浆—热液Zn矿床矿化可划分为三个阶段,早期岩浆房去气阶段,期后热液阶段,以及晚期岩浆房去气阶段。层控Zn矿床流体主要为盆地卤水,矿化机制主要为伸展背景下的海底热液对流,或者挤压环境下,构造挤压与重力的联合驱动,促使流体向盆地边缘迁移成矿。锌矿物的沉淀主要受热液组成、温度、压力、pH以及Eh等因素控制,地质过程中,围岩蚀变、沸腾作用以及流体混合作用等宏观过程促使上述物理化学因素发生变化,从而制约着锌的沉淀。Study shows that zinc element mainly goes into the melt phase, partly being into silicates of iron-magnesium and iron oxides, in silicate melt system. When fluid and melt phase are in separation, zinc preferentially partitions into the hypersaline liquid; However, When brine and vapor are in separation, zinc preferentially enters into the hot brine. During the process of ore-forming, zinc mainly enters into the liquid phase and is transported. And zinc-chloride complex （ZnC_n2-n（0≤n≤4）） is the most important form at which zinc is transported in hydrothermal systems. Oxidation, partial acid, chlorine-rich and sulfide-poor, free Zn2＋, ZnSO40 complex, and Zn-OH-complex are important too under certain conditions. There are other potential inorganic ligands to form zinc complexes such as HS-, CO23-, NH3, F-, Br-, S2-, SO23-, and so on. However, these complexes are insignificant under general geological conditions. Research shows that carboxylate, amino acids, and humic acids are the most important organisms to form zinc-organic complexes, especially the former. They can transport sufficient zinc to form economic deposits below 200℃. The mineralization of magmatic hydrothermal deposit of Zn can be roughly divided into three stages. Early stage of magma degassing in deep magma chamber yields the critical magmatic fluids; during the hydrothermal solutions stage magmatic fluids were derived from magma chamber; afterwards, the magmatic fluids were derived from late stage of degassing in deep magma chamber. The fluid of strata-bound Zn deposit mainly derives from basin brine. The thermal convection of the seafloor in an extensional setting and forces associated with tectonic extrusion control Zn mineralization. Zinc precipitation in hydrothermal solutions is influenced by fluid composition, temperature, pressure, pH and Eh and so on. During ore-forming process, some geological processes such as host rock alteration, boiling and fluid mixing, prompt changes of the physical and chemical conditions （T, P, pH,

关 键 词：锌 热液 分配系数 迁移 络合物 沉淀. 

分 类 号：P611.1[天文地球—矿床学]