平江万古金矿床地球化学研究

平江万古金矿床，成矿物质来源于容矿地层中元古界冷家溪群坪原组，矿床继承了容矿地层富Ａｓ、Ｓｂ、Ｗ等微量元素的特点，成矿流体为与区域浅变质作用有关的ＨＣＯ＿３－－Ｃｌ－－Ｎａ￣＋－Ｃａ￣（２＋）型建造水热液，成矿过程中Ａｕ主要以ＡｕＡｓＳ＿２、ＡｕＡｓＳ＿３￣（２－）络合物形式迁移，矿床形成于中一低温，弱碱性、还原环境。     

东坪金矿床的围岩蚀变和流体特征

东坪金矿床围岩蚀变特征、流体包裹体特征与氢氧同位素特征研究表明，成矿流体富集Ｋ＾＋，Ｎａ＾＋，Ａｕ＾＋，Ｃｌ＾－和ＣＯ２、Ｈ２Ｓ成矿溶液以岩浆热液为主，但有天水的混合。金在溶液中以Ａｕ（ＨＳ）＾－２和ＡｕＣｌ＾－２形式存在，构造活动引起的压力突变和流岩反应是引起金沉淀的主要因素。     

热液体系中Si的络合作用

在不同温度、ＰＨ和硅浓度条件下,实验标定了Ａｕ－ＳｉＯ以及Ｓｎ－ＳｉＯ２之间的络合反应：Ａｕ＾＋＋Ｈ３ＳｉＯ４＾－之间的络合反应：Ａｕ＾＋＋Ｈ４ＳｉＯ＝ＡｕＨ３ＳｉＯ４ ｌｇＫ＝－１．６５４３６＋９６１１．２１／Ｔ;Ｓｎ＾４＋＋４Ｈ３ＳｉＯ４＾－＝Ｓｎ（Ｈ３ＳｉＯ４）４;ｌｇＫ２００ｃ＝４２．７３。通过与Ａｕ－Ｃｌ、Ａｕ－ＨＳ以及Ｓｎ－ＯＨ络合物迁移能力的比较,表明在具地质意义的Ｐ睡ＥＨ条件下,Ａ     

吉林小西南岔金铜矿床流体包裹体及成矿作用研究

该矿床流体包裹体丰富，为２相气液、１相液体、少数含子晶多相和含液态ＣＯ＿２三相包裹体。包裹体液相中富Ｎａ￣＋、Ｃｌ￣－和ＳＯ，气相中Ｈ＿２Ｏ占优势，ＣＯ＿２次之。属ＮａＣｌ－Ｈ＿２Ｏ体系。包裹体同位素分析表明，成矿流体为岩浆水和大气降水的混合流体。在温度高于３６０～４００℃的中性—弱酸性热流体中，Ａｕ和Ｃｕ的络合物呈迁移状态，在温度低的弱酸—酸性的较还原环境下，围岩产生广泛的石英－绢云母化，导致Ａｕ、Ｃｕ络合物分解，沉淀出大量Ａｕ和Ｃｕ。     

金在碱性富硅热液中溶解和迁移的实验研究

实验测定了金在碱性富硅溶液中的溶解度，并标定了Ａｕ与ＳｉＯ２之间的配合关系Ａｕ＾＋Ｈ２ＳｉＯ＾－４＝ＡｕＨ３ＳｉＯ＾０４在８０￣２５０℃的温度范围内，其平衡常数为ｌｇＫ＝－１．９８８９＋１００８５。１８／Ｔ（Ｔ为绝对温度）各温度下的平衡常数值与Ａｕ－ＨＣｌ－ＳｉＯ２－Ｈ２Ｏ体系中得到的结果一致。它表明溶液在酸性和碱性条件下，ＳｉＯ２均作为配位体，与Ａｕ形成ＡｕＨ３ＳｉＯ＾０４在热液中溶解、迁移。Ａ     

哀牢山金矿带深源流体及其成矿作用

深源流体是一种源于深部的高温高压流体，它富含Ｃｌ＾－、ＣＯ２、Ｓ＾２－等矿化剂。金档的形成过程是：深源流体从深部沿高渗透断裂带向上运移过程中，从含金岩体中活化出金而形成含金流体。在含金热流体中，Ａｕ主要以ＡｕＣｌ２＾－、ＡｕＣｌ４＾－、ＡｕＳ２＾－、ＡｕＳＯ３＾３－等形式迁移。当含金流体进入有利的成矿环境中，与围岩发生强烈的交代作用。在交代过程中，金的络合物分解，从而导致金矿床的形成。     

湘西南金矿床成矿流体地球化学研究

流体包裹体地球化学和氢、氧同位素研究表明,湘西南金矿床的成矿流体显示出低温、低盐度、中等密度、低氧逸度、呈中性－弱碱性的特征,成矿流体中的金主要以Ａｕ（ＨＳ）２＾－、ＡｕＨ３ＳｉＯ４＾０等络合物形式迁移,金矿床形成于低温、低压环境条件下,成矿溶液主要来自大气降水。流体包裹体同位素测年与示踪研究表明,该区金矿床并非形成于传统认识中的武陵－雪峰期,而是加里东期成矿,金矿床的成矿物质主要来自赋矿地层而非     

胶东台上金矿成矿机制模拟实验研究

模拟实验研究表明，台上金矿床的成矿机制为：胶东群地层重熔形成滦家河花岗岩岩浆时，初始浆为几乎均匀的熔体相；随着结晶成岩作用的进行，由于局部岩浆结晶分异作用，产生富Ｋ＾＋，Ｎａ＾２＾＋，Ｃａ＾２＾＋，Ｍｇ＾２＾＋，Ｆ＾－，Ｃｌ＾－，Ｓ＾２＾－，ＣＯ３＾２＾－及挥发份ＣＯ２，ＣＯ，Ｈ２Ｏ等的流体相，并不断从已结晶矿物及残熔体中，以［Ａｕ（ＨＳ）２］＾－，［Ａｕ（ＨＳ）Ｓ］＾２＾－，ＡｕＣｌ４］＾－等络     

黔西南微细浸染型金矿床金,砷共生分异机制初步研究

黔西南微细浸染型金矿床成矿热液中金可能主要以Ａｕ（ＨＳ）－２及ＡｕＳ－等迁移形式,砷则主要以Ｈ３ＡｓＯ０３形式迁移。随着成矿热液系统物理化学条件的改变,从成矿前阶段、热液主成矿阶段至晚成矿阶段,金、砷络合物在热液中的沉淀经历了共生、初始分离至分离的富集演化阶段。物理化学条件改变是导致金、砷共生分异的重要因素。     

湘西金-锑-钨矿深部矿化初步预测

湘西金－锑－钨矿产于晚元古代紫红色板岩－－马驿组。该组以富含Ｆｅ２Ｏ３,局部富含ＣａＯ为特技,可能作为地球化学障控制着本区矿床及矿化的分布。湘西金矿中主要控矿要素为：构造、地层及主要成矿元素络合物的地球化学性质。金以Ａｕ（ＨＳ）２＾－形式搬运,共沉淀主要由紫红色板岩的氧化作用而形成的黄铁矿化引起。钨以ＷＯ４和ＨＷＯ４形式存在,温度的降低及局部富围岩的存在控制着其沉淀。锑不仅以Ｓｂ（ＯＨ）３＾０,而     

安徽铜陵狮子山矿田铜、金共生与分离的热力学研究

狮子山矿田是安徽铜陵矿集区内最具代表性的大型铜金多金属矿田.矿田内铜、金矿床或矿体既各自独立产出,义相互共生或伴生,铜矿化和金矿化在时间上和空间上存在既共生又分离的现象.本文选择矿田内代表性铜矿床和金矿床开展系统的流体包裹体地球化学研究,并进行成矿流体中铜、金溶解度的热力学理论计算和1分析,探索铜、金共生与分离的机制和...     

紫木凼含砷微细浸染型金矿床金砷成矿过程初步研究

紫木凼含砷微细浸染型金矿床两个钻孔不同深度金、砷及伴生元素含量变化特征研究结果表明,在矿床深部金与砷密切共生,表现为正相关;而在矿床浅部金与砷关系并不密切,二者不相关或呈负相关,金矿床成矿热液中金可能主要以Ａｕ（ＨＳ）２及ＡｕＳ等形式迁移,砷则主要以Ｈ３ＡｓＯ３形式迁移。随着成矿热液系统物理化学条件的改变,从成矿前阶段、热液主成矿阶段至晚成矿阶段,金、砷络合物在热液中的沉淀经历了共生、初始分离至分     

Geochemistry and evolution of ore-forming fluids of the Yueshan Cu–Au skarn- and vein-type deposits, Anhui Province, South China

The Yueshan mineral belt is geotectonically located at the centre of the Changjiang deep fracture zone or depression of the lower Yangtze platform. Two main types of ore deposits occur in the Yueshan orefield: Cu–Au–(Fe) skarn deposits and Cu–Mo–Au–(Pb–Zn) hydrothermal vein-type deposits. Almost all deposits of economic interest are concentrated within and around the eastern and northern branches of the Yueshan dioritic intrusion. In the vicinity of the Zongpu and Wuhen intrusions, there are many Cu–Pb–Zn–Au–(S) vein-type and a few Cu–Fe–(Au) skarn-type occurrences.Fluid inclusion studies show that the ore-forming fluids are characterised by a Cl⁻(S)–Na⁺–K⁺ chemical association. Hydrothermal activity associated with the above two deposit types was related to the Yueshan intrusion. The fluid salinity was high during the mineralisation processes and the fluid also underwent boiling and mixed with meteoric water. In comparison, the hydrothermal activity related to the Zongpu and Wuhen intrusions was characterised by low salinity fluids. Chlorine and sulphur species played an important role in the transport of ore-forming components.Hydrogen- and oxygen-isotope data also suggest that the ore-forming fluids in the Yueshan mineral belt consisted of magmatic water, mixed in various proportions with meteoric water. The enrichment of ore-forming components in the magmatic waters resulted from fluid–melt partitioning. The ore fluids of magmatic origin formed large Cu–Au deposits, whereas ore fluids of mixed magmatic-meteoric origin formed small- to medium-sized deposits.The sulphur isotopic composition of the skarn- and vein-type deposits varies from − 11.3‰ to + 19.2‰ and from + 4.2‰ to + 10.0‰, respectively. These variations do not appear to have been resulted from changes of physicochemical conditions, rather due to compositional variation of sulphur at the source(s) and by water–rock interaction. Complex water–rock interaction between the ore-bearing magmatic fluids and sedimentary wall rocks was responsible for sulphur mixing. Lead and silicon isotopic compositions of the two deposit types and host rocks provide similar indications for the sources and evolution of the ore-forming fluids.Hydrodynamic calculations show that magmatic ore-forming fluids were channelled upwards into faults, fractures and porous media with velocities of 1.4 m/s, 9.8 × 10^− 1 to 9.8 × 10^− 7 m/s and 3.6 × 10^− 7 to 4.6 × 10^− 7 m/s, respectively. A decrease of fluid migration velocity in porous media or tiny fractures in the contact zones between the intrusive rocks and the Triassic sedimentary rocks led to the deposition of the ore-forming components. The major species responsible for Cu transport are deduced to have been CuCl, CuCl₂⁻, CuCl₃²⁻ and CuClOH, whereas Au was transported as Au₂(HS)₂S²⁻, Au(HS)₂⁻, AuHS and AuH₃SiO₄ complexes. Cooling and a decrease in chloride ion concentration caused by fluid boiling and mixing were the principal causes of Cu deposition. Gold deposition was related to decrease of pH, total sulphur concentration and fO₂, which resulted from fluid boiling and mixing.Geological and geochemical characteristics of the two deposit types in the Yueshan mineral belt suggest that there is a close genetic relationship with the dioritic magmatism. Geochronological data show that the magmatic activity and the mineralisation took place between 130 and 136 Ma and represent a continuous process during the Yanshanian time. The cooling of the intrusions and the mineralisation event might have lasted about 6 Ma. The cooling rate of the magmatic intrusions was 80 to 120 °C my^− 1, which permitted sufficient heat supply by magma to the ore-forming system.     

Thermodynamic study of the association and separation of copper and gold in the Shizishan ore field, Tongling, Anhui Province, China

The Shizishan ore field is the largest gold–copper ore field in the Tongling ore district of Anhui Province, China. Copper and gold deposits in the district are present as one-commodity deposits or as deposits with both commodities. Copper and gold mineralization are either cogenetic or are temporally and spatially distinct. We present the results of systematic geochemical analysis of fluid inclusions from typical Au–Cu deposits in the Shizishan ore field; these data are used to determine the solubility of Cu and Au in the ore-forming fluids and to ascertain the mechanisms and factors that controlled variations in the association and separation of copper and gold mineralization. Our results indicate that copper in the ore-forming fluids was transported as CuCl₂⁻ and CuCl⁰ complexes and that the solubility of copper was controlled by variations in Cl⁻ concentration. In addition, the precipitation of copper was controlled by changes in temperature, pH, fO₂, and fO₂. In comparison, gold in the ore-forming fluids was transported as Au(HS)₂⁻ and Au₂S(HS)₂²⁻ complexes, and the solubility of gold was controlled by variations in total sulfur concentration; the precipitation of gold was controlled by temperature, pH, fO₂, and fO₂. These differences between the two elements meant that copper and gold in the ore-forming fluids responded in different ways to changes in physicochemical conditions. Copper precipitated under relatively acidic conditions at high temperatures, while gold precipitated under weakly alkaline conditions at relatively low temperatures; this dissociation resulted in the temporal and spatial separation and zonation of copper and gold mineralization in the Shizishan ore field.     

安徽月山矿田铜、金矿床氢氧同位素地球化学及成矿流体输运-化学反应成矿动力学

本文基于氢氧同位素的地球化学研究，论述了安徽月山矿田两类铜、金矿床成矿流体的来源、演化及成矿流体输运扣化学反应扣成矿作用动力学过程。结论认为。月山矿田金属矿床成矿流体为具复杂演化历史的岩浆水或多成因水的混合，主要成矿阶段成矿热液均以岩浆水占绝对优势，两类矿床是同源岩浆热液系统在不同的地质、地球化学环境下演化的产物，是成矿流体的等温输运反应及温度梯度输运反应等综合作用的结果。     

内生金矿床的成矿流体

流体具有媒介和作用剂的双重属性,流体作用贯穿于整个内生金矿成矿作用过程.不同地区、不同类型金矿床具有相似的原始成矿流体——来源于上地幔或下地壳的、富含SiO₂、挥发份、成矿元素的C-H-O体系.在从深部至浅部的运移过程中受岩石建造性质、岩石(层)中流体成分的混入以及水-岩反应等因素作用,原始的成矿流体物理化学性质、组成成分等发生了不同程度的改变,最终形成直接导致金矿化的成矿流体.造成成矿流体中金等成矿物质发生沉淀的主要原因是流体的沸腾作用、流体中挥发份的逸失、流体相的分离作用、不同类型流体之间的混合作用以及热液蚀变(水-岩反应)作用等.     

Physicochemical factors of formation of Au-As,Au-Sb,and Ag-Sb deposits

The physicochemical formation conditions of Au-As, Au-Sb, and Ag-Sb ores characterized by similar paragenetic mineral assemblages and sets of major ore elements but differing in their proportions have been studied. The composition of the solutions filling fluid inclusions in minerals of Au-Sb deposits, combined with mineralogical and geochemical data, indicates that these deposits were formed from a near-neutral to alkalescent chloride-sulfide (<5 wt % NaCl) solution. Au-As and Au-Sb deposits were formed from fluids of the same type, consisting of a predominately CO₂-CH₄ gas phase with N₂ and a low-saline chloride-sulfide solution, where Au and Ag were predominantly transported as dihydrosulfide species and Sb as sulfide and hydroxy complexes. Superimposed minerals of the sulfide-sulfosalt stage that precipitated from chloride-rich solutions (up to 30 wt % NaCl equiv), which contained Ca and Fe chlorides in addition to NaCl, are identified at some Au-Sb deposits. These solutions are similar in composition to the ore-forming fluids of Ag-Sb deposits. Chloride complexes are dominant Au and Ag species in acid chloride-rich solutions of Ag-Sb deposits (up to 38 wt % NaCl equiv), while chloride and hydroxy complexes are characteristic of Sb. These solutions are distinguished by high concentrations of Ag, Sb, Cu, Fe, Mn, Bi, Pb, and Zn. The mineralogical and geochemical specialization of Ag-Sb ore is caused by chemical features of highly concentrated chloride solutions enriched in Ag, Sb, and Cu and by a relatively low Au content within the pH interval 3.5–4.0 (10^?6 m). The factors controlling formation of Au-As deposits are a high capacity of a low-chloride sulfide solution with respect to metals and a high Au concentration therein (two orders higher than that of solutions of Ag-Sb deposits). The enrichment of the pyrite-arsenopyrite paragenetic assemblage in gold is a result of juxtaposed stability fields of native gold, arsenopyrite, and pyrite and their mass deposition with a decrease in temperature from 400 to 300°C. The main cause of the specific mineralogy and geochemistry of Au-Sb deposits is a high metal capacity of a near-neutral low-chloride sulfide fluid with respect to Sb, Au, and Ag, but a low Ag content. The mineralogical and fluid inclusion data combined with computer thermodynamic simulation allowed us to establish the factors of ore formation at P-T-X parameters close to natural conditions and made it possible to characterize the joint deposition of gold and silver in quantitative terms.     

Mineralogy and geochemistry of gold-bearing arsenian pyrite from the Shuiyindong Carlin-type gold deposit, Guizhou, China: implications for gold depositional processes

Arsenian pyrite in the Shuiyindong Carlin-type gold deposit in Guizhou, China, is the major host for gold with 300 to 4,000 ppm Au and 0.65 to 14.1 wt.% As. Electron miroprobe data show a negative correlation of As and S in arsenian pyrite, which is consistent with the substitution of As for S in the pyrite structure. The relatively homogeneous distribution of gold in arsenian pyrite and a positive correlation of As and Au, with Au/As ratios below the solubility limit of gold in arsenian pyrite, suggest that invisible gold is likely present as Au¹⁺ in a structurally bound Au complex in arsenian pyrite. Geochemical modeling using the laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) analysis of fluid inclusions for the major ore forming stage shows that the dominant Au species were Au(HS)₂⁻ (77%) and AuHS_(aq)⁰ (23%). Gold-hydroxyl and Gold-chloride complexes were negligible. The ore fluid was undersaturated with respect to native Au, with a saturation index of −3.8. The predominant As species was H₃AsO₃⁰ _(aq). Pyrite in the Shuiyindong deposit shows chemical zonation with rims richer in As and Au than cores, reflecting the chemical evolution of the ore-bearing fluids. The early ore fluids had relatively high activities of As and Au, to deposit unzoned and zoned arsenian pyrite that host most gold in the deposit. The ore fluids then became depleted in Au and As and formed As-poor pyrite overgrowth rims on gold-bearing arsenian pyrite. Arsenopyrite overgrowth aggregates on arsenian pyrite indicate a late fluid with relatively high activity of As. The lack of evidence of boiling and the low iron content of fluid inclusions in quartz, suggest that iron in arsenian pyrite was most likely derived from dissolution of ferroan minerals in the host rocks, with sulfidation of the dissolved iron by H₂S-rich ore fluids being the most important mechanism of gold deposition in the Shuiyindong Carlin-type deposit.     

安徽月山岩体地球化学特征及成因机理分析

通过对长江中下游地区具代表性的大型矽卜岩－热液脉型铜（铁）、金、多金属矿田中成矿岩体－月山岩体的地质地球化学特征及其成因制约与反演讨论，认为该岩体为深源的碱性玄武质岩浆经过结晶分异和同化混染联合作用（AFC过程）形成的，其中，幔源物质约占70％，同化的壳源物质占30％。这种开放岩浆系统的形成与演化对于该区金属矿床成矿流体系统的形成与演化具有极其重要的意义。     

流体的沸腾和混合在热液成矿中的意义

讨论了流体沸腾和混合在热液成矿中的重要作用及研究进展。成矿汉体的降温可能不是许多金属矿物沉淀的最有效机制；流体的沸腾作用对浅成热液帮床，斑岩铜钼等矿床中矿物的沉淀作用很大，造成的矿化具有强度大，品位富及垂向分带较发育的特征，同时因其影响范围小，作用时间短，限制了它的作用的发挥。