滇西北衙金矿床富水岩浆对成矿的制约

成矿岩浆富水(4%)是形成斑岩型矿床的关键。滇西北衙金矿床是金沙江-哀牢山新生代富碱斑岩成矿带中规模最大的金多金属矿床,目前探明金资源储量超过320吨,伴生的铅锌、银、铜、铁、硫也达到大-中型规模。本文以北衙成矿的二长花岗斑岩中角闪石斑晶和锆石为研究对象,开展岩相学和地球化学研究,厘定成矿岩浆的特征,并探讨富水岩浆对成矿的制约。研究表明,北衙二长花岗斑岩角闪石斑晶发育、轻稀土富集而重稀土亏损、具有高Sr(300×10~(-6))、低Y(10×10~(-6))和高(La/Yb)N(6.19~26.8)的地球化学特征,暗示在岩浆结晶早期有角闪石斑晶的晶出。角闪石晶出的条件是岩浆中水含量大于4.5%,因此北衙金矿床成矿岩浆演化早期角闪石的晶出显示成矿岩浆相对富水。角闪石矿物组分计算表明岩浆熔体中水含量在3.8%~4.1%之间,进一步证实北衙金矿床成矿岩浆相对富水。北衙金矿床这种具有高水含量的岩浆在源区岩石部分熔融的过程中,水的加入可以降低其熔点,促进源区含Cu、Au硫化物重熔,或萃取岩石中Cu、Au成矿元素,或聚集岩浆中分散分布的金属元素,形成富金属、富水的岩浆。含矿岩浆就位后,其通过压力的降低(岩浆房脆性破裂或岩浆向上侵位)来降低水的溶解度,或通过岩浆持续的结晶(在等压条件下晶出无水矿物)逐渐提高岩浆水含量,促使熔体中水含量大于水在熔体中溶解度,从而导致岩浆水达到饱和状态,流体开始出溶。总体而言,北衙金矿床富水岩浆不仅能促进北衙矿床成矿流体的形成与演化,也对成矿流体中Cu、Au等成矿元素的富集具有重要的作用。     

Geochemical studies of the formation of gold deposits in the Shaoxing-Longquan Uplift Zone,Zhejiang Province

This paper systematically deals with the geochemical features of major gold deposits in the Shaoxing-Longquan Uplift Zone, Zhejiang Province, including the content and association of ore-forming elements and trace elements, stable isotopic characteristics, the existing forms of gold, and the composition of ore fluids. The authors consider that the ore-bearing formations in this zone are a good supply of necessary elements and ore fluids for the gold deposits in this area. It is also considered that some Au⁺-Cl⁻ and Au⁺-HS⁻ or Au⁺-CO₂ coordinated ions are the main transport forms of gold in ore fluids and the metallogenesis of gold involves two stages: formation of pyrite and mineralization of Cu, Pb and Zn. In this paper is also presented a comprehensive geochemical model for the formation of gold deposits in this uplift zone.     

湘西层控金矿床成因机制的研究

流体包裹体的研究表明,湘西层控金矿床为中低温热液矿床,矿床在弱还原、弱碱性的成矿流体中形成,成矿流体为变质水与建造水混合而成。在流体中金主要以[Au(HS)~-]络离子形式运移,流体温度及pH值的改变是导致金沉淀的主要因素。流体包裹体的研究还揭示,成矿能量主要由雪峰造山作用提供。元素地球化学的研究则证实,湘西元古界是典型的Au-Sb-W含矿建造,它为湘西层控金矿床的形成提供了物质基础。本文的研究显示,湘西层控金矿床的成矿作用是中低温开放体系水、岩反应过程。     

桂西巴马料屯金矿床成矿年代上限的确定——对滇黔桂“金三角”卡林型金矿年代学研究的启示

广西巴马料屯金矿床是较为典型的卡林型金矿床,金矿体与燕山晚期石英斑岩脉空间上相关。矿床勘查成果和野外露头观察均表明石英斑岩脉切割金矿体,说明岩浆岩形成于矿体之后。成矿元素地球化学测量结果表明,Au、As元素沿石英斑岩脉走向出现明显的分异,表现为在导矿和容矿断层区段Au、As质量分数高,局部形成矿（化）体;远离矿体的砂泥岩和灰岩围岩地段,则逐渐降低至正常背景值,说明石英斑岩侵位过程中切割早期的矿体或含矿断层,萃取了矿（化）体中成矿元素Au、As,从而在这些断层之间形成一定宽度的高值带。成矿元素地球化学测量支持岩浆岩形成于矿体之后的结论。石英斑岩脉白云母斑晶的⁴⁰Ar/³⁹Ar坪年龄为（95.5±0.7） Ma,代表了岩浆侵位年龄,由于岩脉形成于矿体之后,此年龄可以作为成矿年代的上限年龄。本矿床及滇黔桂"金三角"其他卡林型金矿的确切成矿年代,尚需更多高精度直接成矿年龄数据的约束。     

江南造山带钨锡稀有金属矿床成矿作用特征

江南造山带是世界上重要的钨锡稀有金属成矿带之一,发育矽卡岩型钨/锡矿、细脉浸染型钨矿、石英脉型黑钨矿/白钨矿、电气石-石英脉型锡矿、云英岩型钨/锡矿和花岗岩-伟晶岩型铌钽矿床,成矿时代包括新元古代、加里东期、印支期和燕山期。依据成矿元素组合,可将成矿花岗岩划分为W-Mo、W、Sn和Nb-Ta花岗岩,其演化程度和地球化学特征显示出明显差异,铌钽矿化发生在极端分异的钠长石花岗岩中。不同时代、不同类型的成矿花岗岩可能来自不同源区的部分熔融,江南造山带可能存在多个稀有金属富集的源区。成矿物质和成矿流体主要源自花岗质岩浆,岩浆分异演化促进了成矿元素在熔体中的富集。铌钽矿主要为岩浆成因,叠加热液矿化,钨锡矿主要通过流体充填和交代作用形成。     

甘肃省夏河县甘加贡玛—阿姨山地区水系沉积物地球化学特征

夏河县地区位于中秦岭断褶带西段,观音大庄—力士山断裂带南侧、夏河—合作断裂带中部,属夏河—合作成矿带。通过开展1 ∶ ５万水系沉积物测量工作,并对异常进行查证解释,从区域地质背景和矿区地质特征入手,重点分析了甘加贡玛—阿姨山地区的水系沉积物金异常,表面该区水系沉积物异常分布与构造展布方向一致,金异常对地层的选择性明显;通过对水系沉积物测量中Au、Ag、Cu、Pb、Zn、As 、Sb、Hg、Cr、Ni、Sn、W、Mo、Bi等14种元素分析结果进行R型聚类分析和相关性分析,得出区内可选用Au、Cu、Pb、Zn 4种元素作为主成矿元素进行成矿预测。     

The intermetallic compound Ni<Subscript>3</Subscript>Au and gold-nickel solid solutions in metalliferous sediments of the triassic chert formation in Sikhote-Alin in the Far East

The intermetallic compound Ni₃Au and Au-Ni solid solutions (native nickel Au and Au-bearing native Ni) were found in the contact metamorphosed metalliferous sediments of the Triassic chert formation in Sikhote-Alin. The metalliferous rocks are characterized by high contents of Au, Ag, and PGE, as well as the presence of diverse minerals of precious metals. Nickel gold (Au0._91-0.88 Ni_0.09-0.12) is found as grains and crystals (3 to 4 im in size) in Au-bearing cherts with hematite, which are conventionally defined as “itabir-ites” and in the altered siliceous rocks of the Dal’nerechensky district (the upper reaches of the Gornya River). The nickel gold is associated with copper Au, pure native Au (Au_1.00), and Au-Ag and Au-Ag-Pb solid solutions (Au_0.86/_0.84Ag_0.14__0.16 and Au_0.78Ag_0.19Pb_0.03, respectively). The Au-bearing Ni is found in the metamorphosed carbonaceous mudstones and Au-bearing “itabirites” of the Shirokopadninsky area (Olgin-sky district). The Au content varies from 6.09 wt % (Ni_0.98Au_0.02) to 11.30 wt % (Ni_0.96Au_0.04) in some Au-bearing Ni grains (about 10—15 im in diameter) taken from the metamorphosed mudstones. The grains of Au-bearing Ni (Co_0.001__0.00Au_00.2 - _0.17 Ni _0.98__0.83) in the “itabirites” are also characterized by their heterogeneous composition and the fine impregnation of the Ni₃ Au intermetallic compound (Ni_2.99Au_1.01 based on the microprobe analysis).     

东南亚中南半岛锡矿带成矿特征

东南亚中南半岛位于特提斯成矿域和西环太平洋成矿域的相交地带,在印支—喜山期发生了多期次俯冲、碰撞造山成矿作用,发育多个与中酸性岩浆活动密切相关的锡（钨）岩浆热液成矿系统,形成了世界著名的东南亚中南半岛锡矿带。研究区自西向东依次可划分为抹谷—毛淡棉—德林达依—普吉锡矿带、景栋—清莱—清迈锡矿带和越北—长山—昆嵩—大叻锡矿带三大锡矿带及7个锡矿亚带,锡矿化花岗岩多为高度分异演化的重熔型铝过饱和花岗岩类,具有多硅、富碱、多挥发分、高钾、87Sr/86Sr初始比值高、Rb/Sr值高、相对明显富集Be、Bi、Cu、Mo、Pb、Sn、Y、Zn等元素的特点。锡矿体主要分布于S型花岗岩与围岩的内、外接触带。锡矿床成矿类型主要有热液脉型、矽卡岩型、锡石—硫化物型、云英岩型、伟晶岩—细晶岩型等。从海西晚期到喜山早期都有锡的成矿事件发生,以燕山期锡成矿作用为主,成矿构造环境主要为岛弧环境和大陆边缘碰撞造山环境。     

东南亚中南半岛锡矿带成矿特征

东南亚中南半岛位于特提斯成矿域和西环太平洋成矿域的相交地带,在印支—喜山期发生了多期次俯冲、碰撞造山成矿作用,发育多个与中酸性岩浆活动密切相关的锡(钨)岩浆热液成矿系统,形成了世界著名的东南亚中南半岛锡矿带。研究区自西向东依次可划分为抹谷—毛淡棉—德林达依—普吉锡矿带、景栋—清莱—清迈锡矿带和越北—长山—昆嵩—大叻锡矿带三大锡矿带及7个锡矿亚带,锡矿化花岗岩多为高度分异演化的重熔型铝过饱和花岗岩类,具有多硅、富碱、多挥发分、高钾、87Sr/86Sr初始比值高、Rb/Sr值高、相对明显富集Be、Bi、Cu、Mo、Pb、Sn、Y、Zn等元素的特点。锡矿体主要分布于S型花岗岩与围岩的内、外接触带。锡矿床成矿类型主要有热液脉型、矽卡岩型、锡石—硫化物型、云英岩型、伟晶岩—细晶岩型等。从海西晚期到喜山早期都有锡的成矿事件发生,以燕山期锡成矿作用为主,成矿构造环境主要为岛弧环境和大陆边缘碰撞造山环境。     

甘肃岷县寨上金矿成矿年代及矿床成因探讨SCIEI北大核心CSCD

寨上金矿位于西秦岭大规模卡林-类卡林型金矿床集中地之中,是近二十年来探获的又一超大型金矿。通过对寨上金矿的6件矿石样品中的载金矿物黄铁矿进行Rb、Sr、Re、Os同位素分析,获得Rb-Sr、Re-Os等时线年龄分别为273±10Ma、273Ma±22Ma。该数据大于前人所获的二期成矿阶段年龄,在西秦岭已探明的金矿床中尚无报道,反映了寨上金矿更早一期的成矿年龄为273Ma,这也为该区域寻找金矿床拓宽了时间轴。Sr、Os、S同位素及稀土和微量元素研究表明,寨上金矿成矿物质为深源与壳源物质的混合。二叠纪时位于岷礼前陆盆地的吴家山隆起经历了强烈的隆升延展作用,岩浆热液沿断裂通道上升到有较高Au背景值盆地中的褶皱带,使地层中的Au活化富集,在构造有利部位卸载成矿,形成早期寨上金矿床,后期钨矿化及金矿化叠加在早期金矿床之上。寨上金矿第一期金成矿的年龄在时空上与阿尼玛卿洋盆闭合、共和坳拉谷俯冲碰撞、江里沟及中川喜马拉雅型岩体的侵入时间基本吻合,符合“地壳加厚有利于形成金矿床及喜马拉雅型花岗岩与金矿关系密切”的结论,对在该区域寻找同时代金矿床具有一定的指示意义。     

金属元素形成原生晕能力定量评价——以青海省扎家同哪金矿为例

在进行原生晕元素分带研究时,所选元素多未进行筛选,不利于正确认识分带规律及指导矿产预测.本文基于扎家同哪金矿2779个钻孑L样品数据,拟通过定量评价不同金属元素在围岩、矿化围岩、矿石等中的富集程度,研究不同元素在矿化过程中形成原生晕的能力差异.研究发现,扎家同哪金矿Au、As、Sb、Hg、W、Ag在围岩、矿化围岩和矿石...     

赵家堡子金矿矿床成因及其找矿标志

赵家堡子金矿位于猫岭-卧龙泉金矿化集中区,是典型的中低温热液矿床。通过区域变质作用,使岩层中的Au、Ag等成矿元素活化,随着变质热液运移到有利的构造部位初步富集;通过应力作用,使岩石发生塑性变形,形成了北西向的韧性剪切带。同时,使Au、Ag等成矿元素再次活化转移、富集;通过后期构造岩浆的大面积侵入,形成了叠加在韧性剪切带之上的北西向韧-脆性断裂和北东向的脆性断裂,同时宏大的热源使地层中的Au再次活化、迁移、富集,同岩浆所带来的大量成矿物质一起在有利的构造部位富集成矿,是本区金矿的主要成矿阶段。     

Trace element geochemistry of the 1991 Mt. Pinatubo silicic melts, Philippines: Implications for ore-forming potential of adakitic magmatism

The dacite pumice erupted from Mt. Pinatubo on June 15, 1991 (whole-rock, rhyolitic groundmass glasses and homogenized melt inclusions) has been analyzed using inductively coupled plasma-mass spectrometry (ICP-MS), nanosecond and femtosecond laser ablation ICP-MS and secondary ion mass spectrometry (SIMS) to evaluate its ore-forming potential. Data suggest that adakite magmas are metal-rich and concentrate ore metals during magmatic differentiation. Sulfides segregate in limited amounts under the hydrous, oxidizing conditions typical of adakitic magmas resulting in incompatible behavior for Au (6-22 ppb), Cu (26-77 ppm), and Pb, Mo, As, and Sb in melts of dacitic to rhyolitic compositions. Metal transfer from this adakite magma to the coexisting aqueous phase was favored by the peraluminous composition of the rhyolitic melt and high aqueous chloride concentrations. Mass balance calculations suggest that the pre-eruptive aqueous phase could have extracted a minimum of 100 t Au and 5 × 10⁵ t Cu from the Mt. Pinatubo magma. Our data suggest that intrusives having adakitic signatures are genetically associated with Au-Cu and Cu-Mo mineralization, auriferous porphyry copper deposits, and epithermal gold veins. High H₂O, Cl, Sr/Y, Pb/Ce, Mo/Ce, As/Ce and Sb/Ce in Mt. Pinatubo melts reflect the contribution of deep fluids derived from subducted sediments and altered MORBs in the dacite genesis. The slab-derived fluids carrying mobile elements are likely responsible for the enrichment of adakite magmas in gold, associated metals and H₂O, and may explain the exceptional ore-forming potential of adakite magmatism.     

Nanomineralogy and nanogeochemistry of ores from gold deposits of Uzbekistan

Gold deposits of Uzbekistan are localized in the Kyzylkum, Nurata, and Kurama ore districts of the Kyzylkum-Kurama metallogenic belt. They comprise a consecutive series of deposit types corresponding to the series of geochemical associations: (Au-W)—(Au-As)—(Au-Te)—(Au-Ag)—(Au-Sb)—(Au-Hg), which are arranged as a system of zones in orebodies, deposits, ore fields, and ore districts. The distribution of chemical elements characterized by average global concentrations in the crust within the ppm-ppb (10⁻⁶-10⁻⁹ t) range was studied in ores of gold deposits using an ICP MS Elan DRC II device. Mineral nanoassemblages with a grain size of 10⁻⁶ to 10⁻⁹ m were examined with a Jeol YXA 8800R Superprobe. The Au-W, Au-As, and Au-Te associations with Bi tellurides and maldonite in ore dominate at hypo- and meso-abyssal gold deposits of the Kyzylkum district (Muruntau, Myutenbay). The contribution of the Au-Sb association with Pb, Ag, and Fe sulfoantimonites and aurostibite increases at the Daughyztau, Kokpatas, and Amantaitau gold deposits. The Au-As, Au-Te, and Au-Sb associations with Bi tellurides, maldonite, sulfoantimonites, and aurostibite dominate at the mesoabyssal gold deposits of the Nurata district (Charmitan, Guzhumsay). The Au-Te and Au-Ag associations with Au, Ag, Pb, Sb, Bi, and Hg tellurides and Bi selenides dominate at the hypabyssal gold deposits of the Kurama district (Kochbulak, Kayragach). The gold-silver deposits of the Kyzylkum district (Kosmanachi, Vysokovol’tnoe) and the Kurama district (Kyzylalmasay, Arabulak) are close in composition. They are characterized by development of intermetallides, sulfides, sulfosalts, and selenides of Au-Ag and occasionally Au-Sb associations. Fineness of gold decreases from early to late geochemical associations, whereas the size of gold grains increases in the same direction from nanogold to visible gold. The studies at the micro- and nanolevel make it possible to establish the attributes of specific gold mineralization, to substantiate prospecting guides, and to estimate the erosion level and resource potential of hidden ore objects. The greater and more diverse a set of micro- and nanominerals, the larger a gold deposit is.     

磐石地区粗榆-小铜矿-带金铜矿地质特征

粗榆一小铜矿地区属磐石一双阳接触带金及多金属成矿带的一部分，有良好的成矿地质环境，成矿物质来源于含金较高的石英闪长岩体和晚石炭纪石嘴子组地层等。热液矿化剂来源于岩浆分异晚期汽水热液和地表水的混合，北西向断裂构造及北东、东西向次级构造控制了地层岩浆岩的分布和矿化作用的演化，长期多期次的构造活动和脉岩的侵入使金铜等成矿元素活化富集，在有利的构造位置成矿。主要矿化类型有石英脉型和破碎带蚀变岩型。     

太行山燕山造山带与中生代花岗岩有关的金属矿床成矿系列特征

在把握成矿系列“三同”基本前提和“五多”基本特征的基础上 ,把太行山—燕山造山带与中生代花岗岩有关的矿床划分为 6个成矿系列 ,并探讨了各成矿系列主要地质特征、稳定同位素特征、成矿热液性质及其物理化学条件 ,指出各成矿系列具有不同的特征 ,岩浆岩、地层、断裂构造等对成矿系列形成都有控制作用 ,成矿物质既来源于围岩 ,也来源于花岗质岩浆 ,并且在造山作用过程中 ,壳幔演化对各成矿系列有不同的贡献。     

Cascaded Evolution of Mantle Plumes and Metallogenesis of Core- and Mantle-derived Elements

Mineral deposits are unevenly distributed in the Earth's crust, which is closely related to the formation and evolution of the Earth. In the early history of the Earth, controlled by the gravitational contraction and thermal expansion, lighter elements, such as radioactive, halogen-family, rare and rare earth elements and alkali metals, migrated upwards; whereas heavier elements, such as iron-family and platinum-family elements, base metals and noble metals, had a tendency of sinking to the Earth's core, so that the elements iron, nickel, gold and silver are mainly concentrated in the Earth's core. However, during the formation of the stratified structure of the Earth, the existence of temperature, pressure and viscosity differences inside and outside the Earth resulted in vertical material movement manifested mainly by cascaded evolution of mantle plumes in the Earth. The stratifications and vertical movement of the Earth were interdependent and constituted the motive force of the mantle-core movement.     

胶东焦家金成矿带2420~3206 m垂深金矿物和黄铁矿微量元素特征

在胶东莱州吴一村地区完成的3266.06 m深钻,是目前焦家金成矿带最深见矿钻孔,研究钻孔揭露的深部矿石中金矿物及黄铁矿微量元素特征,对探讨深部成矿作用演化具有重要意义。笔者采取深钻中2420~3206 m垂深的岩（矿）芯样品进行了详细的岩相学和矿相学研究,结合扫描电镜和电子探针微区分析,研究了矿石中金矿物的赋存状态和成分。对不同成矿阶段形成的黄铁矿进行了LA-ICPMS微量元素分析。研究结果表明,深部矿石中载金矿物主要为黄铁矿,其次为石英、黄铜矿、方铅矿,可见金主要以自然金和银金矿的形式存在,以晶隙金和裂隙金为主,其次为包体金。与浅部金矿床比较,深部金的成色较高。黄铁矿分为6种类型,第Ⅰ成矿阶段形成富Co型黄铁矿Py1,第Ⅱ成矿阶段形成富Ni型黄铁矿Py2a和Py2b,第Ⅲ成矿阶段形成富Au、As型黄铁矿Py3a和富Au、Ag、Pb、Bi型黄铁矿Py3b,第Ⅳ成矿阶段形成贫微量元素黄铁矿Py4。其中,Py1和Py2a发生强烈破碎,裂隙表面对热液中的Au络合物产生吸附作用,对金沉淀富集起重要作用。黄铁矿中Co、Ni、As等微量元素主要以类质同象形式赋存,而Au、Ag、Cu、Pb、Zn、Bi等主要以纳米级、微米级矿物包体形式赋存。Pb+Bi、Cu+Pb+Zn、Te+Bi与Au+Ag呈明显正相关,而Au与As相关性较差。黄铁矿中Co、Ni含量较低,而Au+Ag+As或Au+Ag+Pb+Bi+Cu含量较高指示成矿有利。另外,黄铁矿中Co、Ni含量较高,并且破碎强烈,成矿相关元素含量较高也指示成矿有利。     

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.