云南墨江金矿床成矿作用探讨

云南墨江金矿床位于“三江”褶皱带哀牢山板块结合带北段的墨江－九甲断裂带中。矿体分布于金厂超基性岩体西侧的金厂组烂山段含火山物质的硅质岩、变余粉砂岩和板岩中,矿休由含石英脉、含金硅质岩组成,金矿体受层位的岩性控制。在矿区还分布晚于金矿化形成的镍矿体。金镍矿体共同存在于同一矿区,矿区围岩蚀变种多,与金矿化有关的围岩蚀变主要有硅化、黄铁矿化等。矿体的空间分布与穿插关系表明,金成矿作用开始于晚三叠世以前。     

云南墨江金厂金矿床含铬层状硅酸盐矿物成分标型特征

含铬绢云母类矿物在云南墨江金厂金矿床中广泛出现于黄铁铬绢英岩、黄铁硅质岩、黄铁铬云母岩和石英脉中。含铬绿泥石类矿物主要出现在石英脉、硅质岩、黄铁铬绢英岩中。蒙脱石出现于蚀变围岩中，而高岭石出现于富金石英脉中。本文通过对72个上述矿物电子探针数据的分析，确定了与其成因产状对应的含铬绢云母、含铬伊利石、含铬绿泥石、含铬蒙脱石、高岭石矿物的系列成分标型。研究表明，具最高铬含量的上述矿物样品均位于近金厂岩体穿脉的最北端。在铬铝云母SiO2-Cr2O3关系图上可以看出，不同成矿背景的铬铝绢云母，其Cr、Si离子数有分区特点，而本矿床的铬铝云母成分标型反映其富硅富铬的特点，与金厂超基性岩体的变质热液有关。     

河北张家口金矿黄铁矿的标型特征及其成因意义

黄铁矿是张家口金矿中一种十分重要的载金矿物。泰文通过对黄铁矿的形态、粒度、成分、晶胞参数及其热电性等矿物标型的详细研究,发现当细粒,立方体与五角十二面体晶形共同出现,含较高的As,Co和Ni,晶胞参数大以及具有较高热电系数值时的黄铁矿含金性好。综合黄铁矿的这些标型特征所蕴藏的成因信息,可以得出:张家口金矿为中深成中高温变质热液矿床。     

新疆库布苏金矿化带矿物标型特征研究

论文在简述了金矿化地质的前提下，利用电子探针测试，化学分析，热发光分析，红外分析，热电系数测试，包裹体均一温度和爆裂温度及其成分测试等技术手段，应用相似一类比原则，分析总结出了石英，自然金，黄铁矿等的找矿，预测矿物标型及指示该矿化带成因的矿物标型。并结合地质特征，得出该矿化带金仍有潜力，其成因为同火山岩有关的变质热液成矿，并且经历了至少两个阶段的矿化作用。     

河南小秦东闯金矿床矿物标型特征研究

东闯金矿床为特大石英脉型金矿。通过对矿石中主要矿物黄铁矿、石英及自然金等的标型特征研究,探讨了矿床的成因及评价指标,认为金矿成矿与岩浆热液和老变质岩系（太华群）关系密切。     

滇西南墨江金厂金镍矿床金、镍赋存状态及成矿过程探讨

墨江金厂金镍矿床位于滇西南哀牢山造山带中段,是西南三江地区一个独特的金镍共生矿床。笔者通过野外地矿物主要为针镍矿、辉砷镍矿、锑硫镍矿、黄铁矿等。依据矿(化)脉切割关系、矿石结构构造及矿物共生组合,墨江金厂金镍矿床成岩-成矿期共发育4个世代黄铁矿。沉积变质期以草莓状黄铁矿和胶状黄铁矿为主,热液成矿期可划分为:早阶段石英-针镍矿-辉砷镍矿-锑硫镍矿-黄铁矿;主阶段石英-黄铁矿-毒砂-硫锑铜银矿-自然金;晚阶段方解石-石英-黄铁矿。对矿区赋金镍贯通性矿物黄铁矿进行详细的电子探针分析,结果显示4个世代黄铁矿微量元素有所差异。其中热液主阶段黄铁矿中含有Au、As、Sb、Pb、Zn、Cu、Co、Ni和Te,显示其流体成分复杂。不同阶段黄铁矿Ni含量不同,沉积变质期黄铁矿中Ni含量较低,为0.00%~0.82%,平均0.26%;热液早阶段黄铁矿中Ni含量最高,为0.43%~3.15%,平均1.38%;热液主阶段黄铁矿中Ni含量降低,为0.00%~0.99%,平均0.22%;热液晚阶段黄铁矿中Ni含量最低,为0.00%~0.09%,平均0.03%。研究结果表明墨江金厂金镍矿床中主要含金矿物和含镍矿物形成于热液期,含金矿物形成晚于含镍矿物。Ni在热液流体中的迁移能力与流体温度正相关,温度越高,Ni进入黄铁矿晶格的能力越强。基于上述金、镍成矿过程研究成果,并对比国内外热液镍矿床的地质-地球化学特征,推断墨江金厂金镍矿床是一个受岩浆热液改造的中-低温热液金镍矿床。     

东伙房金矿中黄铁矿和石英的某些标型特征及其找矿意义

主要对黄铁矿及石英的某些标型特征进行研究，并推测成矿的有利部位，研究发现，本区成矿阶段的黄铁矿为ｎ＋ｐ混合型，ｐ型含量愈高，矿化愈好，金品位高值区与热电系数标志值５００～７００部位吻合，主成矿阶段出现（１００）＋（３２１）＋（２１０）＋（３２１）及（１００）＋（２１０）＋（１１１）黄铁矿聚形，石英热发光强度大（大于０．５Ｒ）发光曲线峰多（双峰），总积分强度大于４．３Ｒ是本区主成矿阶段的一个标志。     

东峰顶金矿某些成矿特征及其找矿意义

东峰顶金矿受断裂硫碎带控制，矿石中主要矿物成分有石英，黄铁矿，重晶石及褐铁矿，其标型特征具有成因和找矿意义，成矿流体为中低温、低盐度，弱酸性，低氧逸度和硫逸度，成矿物质主要来源于基底太古界变质岩系，表生作用使金的品位，成色获得大幅度提高。     

云南省墨江县金厂金矿床金银矿物成因矿物学研究

金、银系列矿物在云南墨江金厂金矿床中出现于蛇纹岩、含金石英脉.根据金银矿物的电子探针数据分析,确定了与成因产状对应的形态、赋存状态、矿物共(伴)生组合、化学成分等系列标型.从成矿早期到晚期,金矿物的结晶顺序为自然金→银金矿→自然银,金的成色有下降的趋势,银含量及矿物中微量元素总量却有明显增加的趋势.银金矿中微量元素总量...     

云南墨江金厂镍_金矿床镍矿化地质特征及形成时间

云南墨江金厂镍_金矿床位于北西走向的哀牢山蛇绿混杂岩带,镍矿体分布于金厂超基性岩体接触带附近的北西走向构造破碎带中,含矿围岩主要为上泥盆统金厂组烂山段变余粉砂岩、石英岩和板岩,少数为硅质菱镁岩和蛇纹岩。镍矿体与围岩为过渡关系,多数与金矿体在空间上分离,少数重叠、穿插,镍矿化时间晚于金矿化。镍矿体以强烈铬绢云母化、硅化和黄铁矿化为特征,矿石类型有绿色泥岩稠密浸染状黄铁矿型和石英岩浸染状黄铁矿型两种,含镍0.5%至1.2%。矿石的金属矿物组合为黄铁矿_方硫镍矿_辉砷镍矿_辉锑矿_闪锌矿,镍矿化属于中低温热液矿化。为了了解金厂镍矿化与超基性岩成岩的时间和成因联系,在了解区域超基性岩体形成时代的基础上,测定了两类镍矿体中3个蚀变铬绢云母的40Ar/39Ar年龄。铬绢云母的40Ar/39Ar似坪年龄分别为(63.09±0.16)Ma、(62.05±0.14)Ma和(61.55±0.23)Ma,代表镍矿化时间。镍矿化发生于新生代初,比金厂超基性岩侵入晚240Ma以上,金厂镍_金矿床镍矿体是海西期形成的金厂超基性岩在新生代初受热液淋滤形成的。     

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.     

塔吾尔别克-阿庇因迪斑岩型金矿特征

矿床的形成与矿区二长斑岩岩体有关.岩体内发育4组原生节理或裂隙带,这些节理或裂隙带控制了矿体的分布,特别是它们的交汇部位是成矿的良好部位.矿体形态为脉状、网脉状和透镜体状.有4种矿石类型:黄铁矿石英脉型;黄铁矿硅酸盐石英脉型;黄铁绢英岩型和细脉浸染型.矿床可以划分为2个成矿期:内生成矿期和表生成矿期.内生成矿期划分3个成矿阶段,第2成矿阶段是金矿主成矿阶段.矿物组合为黄铁矿、自然金、银金矿、石英、绿泥石、方解石、白云石、绢云母、白云母和重晶石.矿体的围岩蚀变主要为硅化、绢云母化、黄铁绢英岩化、绿泥石化、硅酸盐化.氢氧同位素、硫同位素以及流体包裹体的研究表明,成矿热液为岩浆热液和大气降水的混合体.成矿热液温度为130℃,成矿压力为22MPa,盐度1.03%,氧逸度-36.7~-38.8,pH=5.8~8.8.成矿流体早期显酸性,晚期显碱性.认为该矿床为浅成低温、低盐度流体成矿,属于次火山斑岩型金矿.     

工准噶尔库布苏金矿床岩脉与金矿成因关系的研究

库布苏金矿床的三个金矿带均产于闪长玢岩和花岗闪长斑岩内。为了研究这些岩脉与金矿的成因关系,测定了含金石英脉中英流体包裹体均一温度、成分、盐度和Ｈ２Ｏ的氢氧同位素,分析了含英脉和相关脉岩及围岩的稀土元素及微量元素,发现石英流体包裹体属有较高的均一温度、低盐度、富ＣＯ２的还原性流体,其阳离子组合为Ｃａ＾２＋〉Ｎａ＾＋〉Ｋ＾＋或Ｎａ＾＋〉Ｋ＾＋〉Ｍｇ＾２＋,阴离子组合属Ｃｌ＾１〉ＳＯ４＾２－〉Ｆ＾－型,     

黑龙江三道湾子金矿含金石英脉与围岩地球化学及地质意义

三道湾子金矿位于大兴安岭燕山期成矿带东南部,为典型的石英脉型岩金矿床.通过对含矿石英脉、石英脉围岩及同期火山岩地球化学特征的研究,探讨了石英脉围岩及同期火山岩的成矿地质构造背景.证据表明三道湾子岩金矿成矿母岩的地球化学成分类似埃达克岩,或有学者所称的“C型埃达克岩”.成矿流体同成矿母岩可能同时形成于来自上地幔的的玄武岩,为上地幔玄武岩底劈上侵到加厚的地壳（>50 km）底部导致下地壳基性岩部分融熔形成的,其成因并非可以用浅成低温热液作单一解释.     

金厂峪金矿床围岩蚀变特征与矿床成因

为了更深入地理解金厂峪金矿床成矿作用,对该金矿床内蚀变围岩的矿物组合、成分及其变化进行了较详细的研究.蚀变带质量平衡分析表明Al₂O₃、MnO、P₂O₅等组分具不活动性.由蚀变围岩向钠长石英脉,在蚀变岩中元素无明显变化.钠长石英脉体的形成与围岩蚀变有关,但两者成因并不相同.金厂峪金矿床的形成可能与深源流体有关     

新疆托库孜巴依金矿床地质特征及成因

新疆托库孜巴依金矿床的地质、地球化学特征以及同位素年龄,氢、氧、硫等同位素测试和流体包裹体研究表明,该矿床经历了热液成矿期和地表氧化期2个成矿期,工业矿体主要富集在热液期的金-硫化物-碲化物-石英阶段。含矿石英脉中黄铁矿的δ(34S)值与围岩硫特征基本相符,具上地幔源δ(34S)分布特征。石英中包裹体氢氧同位素组成落于大气降水线之下,在变质水、岩浆水下部边缘,具混源特征。铅同位素组成落在上地幔和造山带增长线之间偏造山带侧。成矿流体气相成分以水为主,CO2、CO成分很少,液相离子成分以Ca2+,Na+,K+,HCO3-,SO24-为主。流体包裹体的盐度为6.00%～9.44%,密度为0.763～0.922g/cm3。均一温度为275～324,207～273,207～218,191～222℃。托库孜巴依金矿床属于韧性剪切带型金矿床。构造变形作用促使流体萃取了阿勒泰组上亚组第二岩性段变质火山岩或火山沉积岩中的成矿元素,导致金元素在有利的空间形成含金石英脉,后期岩浆侵入活动为金的进一步富集提供了热源和流体。     

九十三沟金矿床地质特征

九十三沟金矿床产于延边复向斜北东端杜荒子-汪清中生代陆相火山断陷盆地东部的石英闪长斑岩内接触带角砾岩中,近南北向断裂构造控制金矿体的产出.成矿物质来自白垩纪浅成侵入体石英闪长斑岩,成矿热液为富含钾质的气水溶液.矿床属岩浆期后中低温热液型金矿床.     

黔东八克金矿床毒砂和黄铁矿微量元素地球化学研究

八克金矿床以矿体和围岩广泛出现毒砂为典型特征,毒砂、黄铁矿为金的主要共生矿物。对矿体及其围岩中毒砂、黄铁矿进行稀土和微量元素地球化学研究,结果显示矿体中毒砂和黄铁矿的稀土元素总量明显低于围岩的毒砂、黄铁矿,从矿体—近矿围岩—远矿围岩,毒砂、黄铁矿都出现铕的明显负异常,铈无明显异常,反映成矿流体具弱还原性;毒砂、黄铁矿微量元素含量呈现出随着成矿流体从早期到晚期的演化而减少,并普遍亏损高场强元素,富集LREE的特征;通过对黄铁矿、毒砂Hf/Sm、Nb/La和Th/La比值分析,表明八克金矿床成矿流体为富Cl型流体;从研究毒砂、黄铁矿Y/Ho、Zr/Hf和Nb/Ta比值变化范围,表明作用于围岩、矿体中的成矿流体从早期-晚期发生了改变,推测晚期成矿流体可能遭受了外来热液的混入;应用毒砂、黄铁矿中的Co/Ni比值,结合已有数据,表明成矿热液具有多来源的特点,成矿流体来源于大气降水与岩浆水不均匀混合。八克金矿是岩浆热液型的含金石英脉型金矿床。     

Gold Mineralization in Banded Iron Formation in the Amalia Greenstone Belt,South Africa: A Mineralogical and Sulfur Isotope Study

The Blue Dot gold deposit, located in the Archean Amalia greenstone belt of South Africa, is hosted in an oxide (± carbonate) facies banded iron formation (BIF). It consists of three stratabound orebodies; Goudplaats, Abelskop, and Bothmasrust. The orebodies are flanked by quartz‐chlorite‐ferroan dolomite‐albite schist in the hanging wall and mafic (volcanic) schists in the footwall. Alteration minerals associated with the main hydrothermal stage in the BIF are dominated by quartz, ankerite‐dolomite series, siderite, chlorite, muscovite, sericite, hematite, pyrite, and minor amounts of chalcopyrite and arsenopyrite. This study investigates the characteristics of gold mineralization in the Amalia BIF based on ore textures, mineral‐chemical data and sulfur isotope analysis. Gold mineralization of the Blue Dot deposit is associated with quartz‐carbonate veins that crosscut the BIF layering. In contrast to previous works, petrographic evidence suggests that the gold mineralization is not solely attributed to replacement reactions between ore fluid and the magnetite or hematite in the host BIF because coarse hydrothermal pyrite grains do not show mutual replacement textures of the oxide minerals. Rather, the parallel‐bedded and generally chert‐hosted pyrites are in sharp contact with re‐crystallized euhedral to subhedral magnetite ± hematite grains, and the nature of their coexistence suggests that pyrite (and gold) precipitation was contemporaneous with magnetite–hematite re‐crystallization. The Fe/(Fe+Mg) ratio of the dolomite–ankerite series and chlorite decreased from veins through mineralized BIF and non‐mineralized BIF, in contrast to most Archean BIF‐hosted gold deposits. This is interpreted to be due to the effect of a high sulfur activity and increase in fO₂ in a H₂S‐dominant fluid during progressive fluid‐rock interaction. High sulfur activity of the hydrothermal fluid fixed pyrite in the BIF by consuming Fe²⁺ released into the chert layers and leaving the co‐precipitating carbonates and chlorites with less available ferrous iron content. Alternatively, the occurrence of hematite in the alteration assemblage of the host BIF caused a structural limitation in the assignment of Fe³⁺ in chlorite which favored the incorporation of magnesium (rather than ferric iron) in chlorite under increasing fO₂ conditions, and is consistent with deposits hosted in hematite‐bearing rocks. The combined effects of reduction in sulfur contents due to sulfide precipitation and increasing fO₂ during progressive fluid‐rock interactions are likely to be the principal factors to have caused gold deposition. Arsenopyrite–pyrite geothermometry indicated a temperature range of 300–350°C for the associated gold mineralization. The estimated δ³⁴S_ΣS (= +1.8 to +2.5‰) and low base metal contents of the sulfide ore mineralogy are consistent with sulfides that have been sourced from magma or derived by the dissolution of magmatic sulfides from volcanic rocks during fluid migration.     

Geology and Mineral Chemistry of Gold Mineralization in Mirge‐Naqshineh Occurrence (Saqez,NW Iran): Implications for Transportation and Precipitation of Gold

The Mirge-Naqshineh gold district is situated at northwest of Iran with a NW-trending brittleductile shear zone. It is hosted by Precambrian meta-sedimentary and meta-volcanic units traversed by mineralized quartz veins. In terms of cross-cutting relationships and sulfide content three types of quartz veins are identified in the region. Among those, parallel to bedding quartz vein(type Ⅰ) is the main host for gold mineralization. Gold is found in three different forms: 1) submicrometer-size inclusions of gold in arsenian pyrite, 2) as electrum and 3) in the crystal lattice of sulfides(pyrite, galena and chalcopyrite). Six types of pyrite(Py1-Py6) were identified in this ore reserve. Py3 coexists with arsenopyrite and contains the greatest As-Au concentrations. There is a negative correlation between the As and S contents in Py2 and Py3, implying the substitution of sulfur by arsenic. Pyrites and mineralized quartz veins were formed via metamorphic-hydrothermal fluid and reflect the gold-transportation as Au(HS)_2~- under reducing and acidic conditions. The gold precipitation mainly controlled by crystallization of arsenian pyrite during fluid/rock interactions and variation of fO_2. The volcanic host rock has played an important role in gold concentration, as Py3 in this rock contains inclusion of gold particles, but gold is within the lattice of pyrite in phyllite or other units.