湘西金矿外围石英脉含金性评价的矿物学标志

笔者对湘西金矿外围(东部)层间石英脉的主要载金矿物——石英进行了含金性评价的矿物学研究,除了石英的标型特征及包裹体评价之外,还着重进行了谱学评价,包括红外光谱(IR)、电子顺磁共振谱(EPR)、热发光光谱(TL)、X射线粉晶衍射谱(XRPD)以及阴极发光光谱(CL)等近代测试新方法,其中运用阴极发光光谱对石英脉含金性进行评价尚属首次,并据总结出的石英脉含金性评价的矿物学标志,预测了外围四个工作小区的成矿远景。     

湘西金矿石英的矿物学特征研究

在系统地研究湘西金矿中石英的杂质成分、包裹体、晶胞参数及某些谱学的矿物学特征的基础上,讨论了与金成矿作用的关系.最后提出湘西金矿带找矿标志的建议.     

赛乌素金矿床的某些地球化学特征及地球化学找矿标志

论述了赛乌素石英脉型金矿床的某些地球化学特征、含金与不含金石英脉的区别及含金石英脉赋矿部位的地球化学特征。重点是论述含金石英脉的地球化学垂直变化规律和异常分带特点。总结出石英脉的含矿(金)预测标志。     

四川盆地大气层中矿物颗粒-甲苯-Cr3+耦合规律模拟研究

四川盆地大气层具有湿度高和流通性弱的特征,冬春低温季节易形成雾霾。本文着重构建了低温高湿条件下的石英、方解石纳米颗粒与甲苯、Cr~(3+)共存体系,系统测试了石英、方解石颗粒与甲苯、Cr~(3+)耦合前后Zeta电位值、胶体粒径及团聚形态、亲疏水性的变化趋势,以模拟研究四川盆地低温高湿静稳大气环境中矿物颗粒、有机物、重金属离子之间的耦合作用规律。研究发现:甲苯、Cr~(3+)与石英、方解石之间存在显著的成键耦合作用,甲苯、Cr~(3+)存在时会大幅度降低高湿度环境中石英、方解石颗粒的Zeta电位值,增大两种矿物颗粒在低温条件下的活跃度; Cr~(3+)可通过静电作用力,促使石英、方解石颗粒在高湿度环境中形成粒径更大的团聚状胶体;甲苯吸附在石英和方解石颗粒表面会增强其疏水性,减弱高湿度水分对矿物胶体稳定性的侵扰。上述有关石英/方解石颗粒、甲苯、Cr~(3+)在低温高湿条件下的界面成键耦合作用规律发现,对理解四川盆地雾霾形成机制有积极的启发意义。     

吉林夹皮沟金矿床含金石英的~(40)Ar/~(39)Ar快中子活化年龄测定

该文对夹皮沟金矿区有代表性的两个矿床及一个矿点的含金石英脉,用快中子活化法测定了~(40)Ar/~(39)Ar年龄。其年龄谱都以马鞍形为特征,年龄谱的最低坪年龄可作为石英脉的生成时代。3个数据分别为1824±24Ma、1253±17Ma和203±60Ma。由此认为夹皮沟矿区,金的成矿作用是多阶段的,吕梁期、晋宁期和燕山早期。而金矿的成因主要与吕梁期和晋宁期的变质作用有关,因此夹皮沟金矿可划为变质热液型金矿床。     

祁连山西段党河南山北坡3个不同特征的金矿床研究

黑刺沟金矿床以富As和Sb的微细浸染蚀变岩型金矿化和部分石英脉型锑－金矿化为特征,典型矿物组合为黄铁矿-毒砂(辉锑矿)-石英;贾公台金矿床以少硫化物石英脉型金矿化和蚀变岩型金矿化为特征,As和Sb的质量分数不高,典型矿物组合为黄铁矿-自然金(方铅矿)-石英-钾长石;鸡叫沟金矿床以蚀变岩型金矿化为主,次之为石英脉型金矿化,典型矿物组合为黄铁矿-黄铜矿-石英.3个金矿床的成因均与岩浆岩有密切联系,但各矿区的岩浆岩在岩石学、岩石化学、微量元素及稀土元素特征具有差异,表明其成因不尽相同.这可能是造成3个金矿床地质特征差异的主要原因.     

载金石英的化学成分特征及其意义

利用电子显微镜(EM)及能谱仪(EDS),分析研究了变生热液形成的载金石英的化学成分、离子扩散作用以及金在石英中的赋存状态等问题,探讨了它们的形成和变化机理。研究结果表明:Al~(3+)、Ti~(3+)、TFe、Na~(+)、K~(+)、Ca~(2+)等在石英中为类质同像混入物;石英和黄铁矿之间的离子相互扩散作用,表现为石英中Al离子的带出和Fe离子的带入,黄铁矿中Fe离子的带出和Al离子的带入;石英中呈分散状态分布的金主要为离子金,它们充填在石英结构中,起平衡电价的作用。     

浅成低温热液贵金属体系中金与氧化硅的胶体搬运(内华达州斯利泊矿床获得的证据)

内华达州斯利泊(Sleeper)矿床富矿脉型金矿石,系在小于500米的深度范围内沉淀形成,并具有细粒石英胶状条带与含有大量银金矿的蛋白石质氧化硅胶状条带交替的特殊结构.这种结构迹象表明石英条带是从原始的胶状非晶质状态重结晶而来,而富金条带系由氧化硅与金颗粒凝胶组成的非晶质析出物原始沉积而成.金与氧化硅首先在热液体系的较深部位以胶体形式析出,然后由成矿溶液的水力作用向上机械搬运,由于溶液的冷却或沸腾,并在复合阳离子Al~(3+)的水化物的催化下产生胶粒凝结。浅成低温热液体系中金以胶粒形式搬运表明,至少在某些条件下胶体中的金含量比真溶液中要高.欲解释斯利泊矿床富矿石的成因,需存在一种富金的成矿溶液;而胶体金的局部搬运可能对浸染状低温热液金矿床的形成起了一定的作用.     

谱学找金矿的新方法

本文重点介绍了电子顺磁共振谱、拉曼光谱、穆斯堡尔谱、红外光谱、热发光光谱、X射线荧光光谱对石英、黄铁矿、毒砂的含金与不含金的谱学特征进行了分析,从而为寻找金矿床和评价金矿床提供了信息。     

吉林夹皮沟金矿床含金石英的40Ar/39Ar快中子活化年龄测定

该文对夹皮沟金矿区有代表性的两个矿床及一个矿点的含金石英脉，用快中子活化法测定了⁴⁰Ar/³⁹Ar年龄。其年龄谱都以马鞍形为特征，年龄谱的最低坪年龄可作为石英脉的生成时代。3个数据分别为(1824±24)Ma、(1253±17)Ma和(203±60)Ma。由此认为夹皮沟矿区，金的成矿作用是多阶段的，吕梁期、晋宁期和燕山早期。而金矿的成因主要与吕梁期和晋宁期的变质作用有关，因此夹皮沟金矿可划为变质热液型金矿床。     

河北张家口金矿石英的标型特征及其成因意义

本文详尽地研究了张家口金矿两种主要含矿石英（乳白色石英和烟灰色石英）的气液包裹体特征、显微变形特征、成分标型特征、气液包裹体成分特征及晶胞参数标型特征，对比了两种石英含金性的差异与上述各类特征间的关系，并将该矿床的石英标型特征与国内外一些典型矿床的石英标型特征进行了对比，在此基础上得出：烟灰色石英与乳白色石英具有不同的气液包裹体特征、显微变形特征和微量元素特征，张家口金矿的成矿溶液为一种具低中等盐度、弱碱性、Ｎａ￣（＋）－Ｃａ￣（２＋）－Ｃｌ￣（－）型及Ｎａ￣（＋）－Ｃａ￣（２＋）－ＳＯ型、中深成、中高温热水溶液。结合矿床产出的地质背景，文章最后得出：张家口金矿为中高温、中深成变质热液型金矿床。     

冀西北张全庄金矿石英的矿物学特征

本文较为详尽地研究了张全庄金矿两种主要含矿石英（乳白色和烟灰色石英）的成分特征、气液包裹体成分特征及晶胞参数特征等,对比了两种石英含金性的差异及与上述各特征间的内在联系,在此基础上得出;烟灰色石英与乳白色石英具有不同的矿物学特征;张全庄金矿的成矿溶液为一种弱碱性、Ｎａ^＋－Ｃａ^２＋－ＳＯ型,属中（深）成、中（高）温热液型矿床．     

黄铁矿与石英含金机理探讨

从晶体结构化学角度出发，分析了金的电子结构及性质、黄铁矿晶体结构特点、二氧化硅的电子结构特点和石英晶体表面特征；探讨了Au^＋和Au^－离子形式分别替代Fe^2 离子和S^2-离子的形成机理以及以可见金方式在黄铁矿中的赋存机制；认为金在黄铁矿中的富集主要与其晶体结构有关，特别是与黄铁矿中Fe-S，S-S，Au-S和Fe-Au键的电子结构特点有关；应用稳定配合物的18电子规则和晶体生长的界面相模型探讨了石英含金机理；研究表明，石英含金不仅与石英表面的结构、内部缺陷和表面特征有关，还与石英生长的环境有关，尤其是与石英表面键的电子结构特点有关，并主要受石英晶体生长过程中的界面相的控制。     

Mineralogy of the Boroo Gold Deposit in the North Khentei Gold Belt,Central Northern Mongolia

Mineral assemblages and chemical compositions of ore minerals from the Boroo gold deposit in the North Khentei gold belt of Mongolia were studied to characterize the gold mineralization, and to clarify crystallization processes of the ore minerals. The gold deposit consists of low‐grade disseminated and stockwork ores in granite, metasedimentary rocks and diorite dikes. Moderate to high‐grade auriferous quartz vein ores are present in the above lithological units. The ore grades of the former range from about 1 to 3 g/t, and those of the latter from 5 to 10 g/t, or more than 10 g/t Au. The main sulfide minerals in the ores are pyrite and arsenopyrite, both of which are divisible into two different stages (pyrite‐I and pyrite‐II; arsenopyrite‐I and arsenopyrite‐II). Sphalerite, galena, chalcopyrite, and tetrahedrite are minor associated minerals, with trace amounts of bournonite, boulangerite, geerite, alloclasite, native gold, and electrum. The ore minerals in the both types of ores are variable in distribution, abundance and grain size. Four modes of gold occurrence are recognized: (i) “invisible” gold in pyrite and arsenopyrite in the disseminated and stockwork ores, and in auriferous quartz vein ores; (ii) microscopic native gold, 3 to 100 µm in diameter, that occurs as fine grains or as an interstitial phase in sulfides in the disseminated and stockwork ores, and in auriferous quartz vein ores; (iii) visible native gold, up to 1 cm in diameter, in the auriferous quartz vein ores; and (iv) electrum in the auriferous quartz vein ores. The gold mineralization of the disseminated and stockwork ores consists of four stages characterized by the mineral assemblages of: (i) pyrite‐I + arsenopyrite‐I; (ii) pyrite‐II + arsenopyrite‐II; (iii) sphalerite + galena + chalcopyrite + tetrahedrite + bournonite + boulangerite + alloclasite + native gold; and (iv) native gold. In the auriferous quartz vein ores, five mineralization stages are defined by the following mineral assemblages: (i) pyrite‐I; (ii) pyrite‐II + arsenopyrite; (iii) sphalerite + galena + chalcopyrite; (iv) Ag‐rich tetrahedrite‐tennantite + bournonite + geerite + native gold; and (v) electrum. The As–Au relations in pyrite‐II and arsenopyrite suggest that gold detected as invisible gold is mostly attributed to Au⁺¹ in those minerals. By applying the arsenopyrite geothermometer to arsenopyrite‐II in the disseminated and stockwork ores, crystallization temperature and logfs₂ are estimated to be 365 to 300 °C and –7.5 to –10.1, respectively.     

黑龙江省黑河市北大沟金矿床流体包裹体研究

黑龙江省黑河市北大沟金矿床是近年来在大兴安岭燕山期成矿带发现的小型金矿床。对石英脉中流体包裹体岩相学研究、显微测温和气液相成分分析表明:(1)主成矿阶段石英脉中发育纯液相、气液两相、富气相和纯气相4类包裹体。(2)流体包裹体均一温度在160~380℃之间,主要集中在260~300℃;成矿流体为NaCl-H2O体系;流体包裹体盐度估计在0.2%~2.0%(NaCleq)之间;成矿流体密度估计在0.550~0.912 g/cm3之间;成矿压力估计在6×105~210×105Pa之间;估算成矿深度为0.06~2.10 km。(3)从流体包裹体成分分析获得的pH值为6.6~6.7之间,还原参数n(CH4+CO+H2)/n(CO2)(摩尔数比值)在0.027~0.271之间,表明具有浅成中偏酸性和弱还原环境成矿的特点。该矿床是与火山热液有关的浅成中—低温热液金矿床。     

辽宁丹东五龙矿区石英脉型金矿床的黄铁矿标型特征研究

详细研究了辽宁丹东五龙矿区石英脉型金矿床中黄铁矿的产状、形态、成分、硫同位素及热电效应等特征,提取了五龙金矿黄铁矿中重要的成因和找矿信息。首次利用黄铁矿微量元素的三角形图解对矿区深部远景及其外围靶区内矿脉的矿化远景进行了预测,不仅为五龙金矿的成因研究提供了可信的矿物学依据,而且对五龙矿区深部及其外围靶区内矿脉的矿化远景进行了有效的评价,认为五龙金矿系中-浅成岩浆热液成因的金矿床,矿区深部及其外围的220号脉、38号脉、2号脉的金矿化远景较佳。     

Geochemical characteristics of gold mineralization of the Huai Kham On deposit,Sukhothai Fold Belt,Northern Thailand

The Huai Kham On gold deposit is located in the central part of the Sukhothai Fold Belt, northern Thailand. The Sukhothai Fold Belt represents an accretionary complex formed by subduction and collision between the Indochina and Sibumasu Terranes. There are many small gold deposits in the Sukhothai Fold Belt; however, the styles and formation environments of those gold deposits are not clear. The geology of the Huai Kham On deposit consists of volcanic and volcanosedimentary rocks, limestone, and low‐grade metamorphic rocks of Carboniferous to Triassic age. Gold‐bearing quartz veins are hosted by volcanic and volcanosedimentary rocks. The quartz veins can be divided into four stages. The mineral assemblage of the gold‐bearing quartz veins of Stages I and II comprises quartz, calcite, illite, pyrite, native gold, galena, chalcopyrite, and sphalerite. Quartz veins of Stage III consist of microcrystalline quartz, dolomite, calcite, pyrite, native gold, and chalcopyrite. Veins of Stage IV consist of calcite, dolomite, chlorite, and quartz. Fluid inclusions in quartz veins are classified into liquid‐rich two‐phase (Types I_A and I_B), carbonic‐aqueous (Type II), and carbonic (Type III) fluid inclusions. The homogenization temperatures of Types I_A and II fluid inclusions that are related to the gold‐bearing quartz veins from Stages I to III ranged from 240° to 280°C. The δ¹⁸O values of quartz veins of Stages I to III range from +12.9 to +13.4‰, suggesting the presence of a homogeneous hydrothermal solution without temperature variation such as a decrease of temperature during the formation of gold‐bearing quartz veins from Stages I to III in the Huai Kham On gold deposit. Based on the calculated formation temperature of 280°C, the δ¹⁸O values of the hydrothermal solution that formed the gold‐bearing quartz veins range from +3.2 to +3.7‰, which falls into the range of metamorphic waters. The gold‐bearing quartz veins of the Huai Kham On deposit are interpreted to be the products of metamorphic water.     

辽宁五龙金矿含金石英脉中石英标型特征及其找矿意义

辽宁五龙金矿含金石英脉中石英晶体的塑性变形显微裂隙和熔融现象普遍发育,在无矿石英脉中上述现象则不发育或缺失.气液包体在含金石英脉中数量多.成矿温度阶段性明显,沸腾现象也较发育.而在无矿石英脉中则反之.据包体化学成分推测成矿溶液化学成分属CO₂-H₂O-Cl-Na-Ca型,而无矿石英脉热液成分为CO₂-H₂O-F(Cl)-K-Ca(Mg)型,石英中微量元素浓集克拉克值(C_k)及相关系数表明Au、Sb、Bi、W、Ag为本区主要成矿元素.且含金石英脉的C_k值均大于无矿石英脉.热发光曲线在含金石英脉中主要为双峰和多峰型,而无矿石英脉则为单峰型,上述石英标型特征作为五龙金矿床石英脉中找金的重要标志.     

Gold Mineralization of the Gatsuurt Deposit in the North Khentei Gold Belt,Central Northern Mongolia

Mineral assemblages, chemical compositions of ore minerals, wall rock alteration and fluid inclusions of the Gatsuurt gold deposit in the North Khentei gold belt of Mongolia were investigated to characterize the gold mineralization, and to clarify the genetic processes of the ore minerals. The gold mineralization of the deposit occurs in separate Central and Main zones, and is characterized by three ore types: (i) low‐grade disseminated and stockwork ores; (ii) moderate‐grade quartz vein ores; and (iii) high‐grade silicified ores, with average Au contents of approximately 1, 3 and 5 g t^?1 Au, respectively. The Au‐rich quartz vein and silicified ore mineralization is surrounded by, or is included within, the disseminated and stockwork Au‐mineralization region. The main ore minerals are pyrite (pyrite‐I and pyrite‐II) and arsenopyrite (arsenopyrite‐I and arsenopyrite‐II). Moderate amounts of galena, tetrahedrite‐tennantite, sphalerite and chalcopyrite, and minor jamesonite, bournonite, boulangerite, geocronite, scheelite, geerite, native gold and zircon are associated. Abundances and grain sizes of the ore minerals are variable in ores with different host rocks. Small grains of native gold occur as fillings or at grain boundaries of pyrite, arsenopyrite, sphalerite, galena and tetrahedrite in the disseminated and stockwork ores and silicified ores, whereas visible native gold of variable size occurs in the quartz vein ores. The ore mineralization is associated with sericitic and siliceous alteration. The disseminated and stockwork mineralization is composed of four distinct stages characterized by crystallization of (i) pyrite‐I + arsenopyrite‐I, (ii) pyrite‐II + arsenopyrite‐II, (iii) galena + tetrahedrite + sphalerite + chalcopyrite + jamesonite + bournonite + scheelite, and iv) boulangerite + native gold, respectively. In the quartz vein ores, four crystallization stages are also recognized: (i) pyrite‐I, (ii) pyrite‐II + arsenopyrite + galena + Ag‐rich tetrahedrite‐tennantite + sphalerite + chalcopyrite + bournonite, (iii) geocronite + geerite + native gold, and (iv) native gold. Two mineralization stages in the silicified ores are characterized by (i) pyrite + arsenopyrite + tetrahedrite + chalcopyrite, and (ii) galena + sphalerite + native gold. Quartz in the disseminated and stockwork ores of the Main zone contains CO₂‐rich, halite‐bearing aqueous fluid inclusions with homogenization temperatures ranging from 194 to 327°C, whereas quartz in the disseminated and stockwork ores of the Central zone contains CO₂‐rich and aqueous fluid inclusions with homogenization temperatures ranging from 254 to 355°C. The textures of the ores, the mineral assemblages present, the mineralization sequences and the fluid inclusion data are consistent with orogenic classification for the Gatsuurt deposit.