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1.
The Laloki and Federal Flag deposits are two of the many (over 45) polymetallic massive sulfide deposits that occur in the Astrolabe Mineral Field, Papua New Guinea. New data of the mineralogical compositions, mineral textures, and fluid inclusion studies on sphalerite from Laloki and Federal Flag deposits were investigated to clarify physiochemical conditions of the mineralization at both deposits. The two deposits are located about 2 km apart and they are stratigraphically hosted by siliceous to carbonaceous claystone and rare gray chert of Paleocene–Eocene age. Massive sulfide ore and host rock samples were collected from each deposit for mineralogical, geochemical, and fluid inclusion studies. Mineralization at the Laloki deposit consists of early‐stage massive sulfide mineralization (sphalerite‐barite, chalcopyrite, and pyrite–marcasite) and late‐stage brecciation and remobilization of early‐stage massive sulfides that was accompanied by late‐stage sphalerite mineralization. Occurrence of native gold blebs in early‐stage massive pyrite–marcasite‐chalcopyrite ore with the association of pyrrhotite‐hematite and abundant planktonic foraminifera remnants was due to reduction of hydrothermal fluids by the reaction with organic‐rich sediments and seawater mixing. Precipitation of fine‐grained gold blebs in late‐stage Fe‐rich sphalerite resulted from low temperature and higher salinity ore fluids in sulfur reducing conditions. In contrast, the massive sulfide ores from the Federal Flag deposit contain Fe‐rich sphalerite and subordinate sulfarsenides. Native gold blebs occur as inclusions in Fe‐rich sphalerite, along sphalerite grain boundaries, and in the siliceous‐hematitic matrix. Such occurrences of native gold suggest that gold was initially precipitated from high‐temperature, moderate to highly reduced, low‐sulfur ore fluids. Concentrations of Au and Ag from both Laloki and Federal Flag deposits were within the range (<10 ppm Au and <100 ppm Ag) of massive sulfides at a mid‐ocean ridge setting rather than typical arc‐type massive sulfides. The complex relationship between FeS contents in sphalerite and gold grades of both deposits is probably due to the initial deposition of gold on the seafloor that may have been controlled by factors such as Au complexes, pH, and fO2 in combination with temperature and sulfur fugacity. 相似文献
2.
D. B. Bondar’ A. V. Chugaev Yu. S. Polekhovskii N. N. Koshlyakova 《Moscow University Geology Bulletin》2018,73(4):380-389
The ore mineralogy of the largest quartz vein, Osinovaya, at the Kedrovskoe gold deposit has been studied. Three stages of mineral formation, namely, marcasite–pyrrhotite–pyrite, gold–polysulfide, and hypergenic stages are identified. Native gold is attributed to the gold–polysulfide stage and is represented by two generations. The earlier high fineness generation (600–870, 780–820 prevails) cements the fragments of pyrite grains or forms inclusions in pyrite, and the later low fineness generation (520–580, 540–580 prevails) is associated with sphalerite–chalcopyrite–galena veinlets in pyrite. The disappearance of arsenious pyrite, the increase in iron content of sphalerite, and the change in pyrite to pyrrhotite with depth is recorded. 相似文献
3.
Petrography, mineralogy and geochemistry of the Zarshuran Carlin-like gold deposit, northwest Iran 总被引：1，自引：0，他引：1
Gold mineralisation at Zarshuran, northwestern Iran, is hosted by Precambrian carbonate and black shale formations which
have been intruded by a weakly mineralised granitoid. Granitoid intrusion fractured the sedimentary rocks, thereby improving
conditions for hydrothermal alteration and mineralisation. Silicification is the principal hydrothermal alteration along with
decalcification and argillisation. Three hydrothermal sulphide mineral assemblages have been identified: an early assemblage
of pyrrhotite, pyrite and chalcopyrite; then widespread base metal sulphides, lead-sulphosalts and zoned euhedral arsenical
pyrite; and finally late network arsenical pyrite, massive and colloform arsenical pyrite, colloform sphalerite, coloradoite,
and arsenic–antimony–mercury–thallium-bearing sulphides including orpiment, realgar, stibnite, getchellite, cinnabar, lorandite
and a Tl-mineral, probably christite. Most of the gold at Zarshuran is detectable only by quantitative electron microprobe
and bulk chemical analyses. Gold occurs mainly in arsenical pyrite and colloform sphalerite as solid solution or as nanometre-sized
native gold. Metallic gold is found rarely in hydrothermal quartz and orpiment. Pure microcrystalline orpiment, carbon-rich
shale, silicified shale with visible pyrite grains and arsenic minerals contain the highest concentrations of gold. In many
ways Zarshuran appears to be similar to the classic Carlin-type sediment-hosted disseminated gold deposits. However, relatively
high concentrations of tellurium at Zarshuran, evidenced by the occurrence of coloradoite (HgTe), imply a greater magmatic
contribution in the mineralising hydrothermal solutions than is typical of Carlin-type gold deposits.
Received: 13 May 1999 / Accepted: 2 February 2000 相似文献
4.
对云南、海南、江西、湖北、河南、新疆、浙江、山东、辽宁等27个省185个典型金矿床的自然重砂矿物进行统计分析,发现自然重砂矿物对金矿具有良好的响应,自然金、黄铁矿、方铅矿、黄铜矿、白铅矿、辰砂等对寻找金矿具有指示意义。不同成因类型的金矿床反映出的自然重砂矿物组合不同,斑岩型金矿床的标型指示矿物组合为自然金+黄铁矿+方铅矿+重晶石+闪锌矿+白铅矿+金红石,卡林型—类卡林型金矿床的标型指示矿物组合为自然金+黄铁矿+方铅矿+辉锑矿+毒砂+雄(雌)黄,而造山型+矽卡岩型+热液型+构造蚀变岩型金矿床的标型指示矿物组合为自然金+黄铁矿+方铅矿+辰砂。不同区域的金矿床反映出的自然重砂矿物组合也各有差异,闪锌矿为南方各省金矿床的特征矿物,辰砂和白钨矿为北方地区金矿床的特征矿物,重晶石和白铅矿为西部地区金矿的特征矿物。综合研究认为,自然重砂具有直接找矿和指导找矿的作用,按照特定成因类型和区域金矿床所建立的自然重砂矿物组合对建立矿床找矿模型具有重要的意义。 相似文献
5.
胶莱盆地陆源碎屑层控金矿床矿石特征研究 总被引：3，自引：0，他引：3
产于胶莱盆地内由富Au和C有机岩石组成的含矿系中的金矿床，其含矿层位为下白垩统莱阳群一套含碳陆相碎屑岩系，它控制了蓬家夼，宋家沟式金矿的展布。对两类金矿床矿石特征进行了研究及对比，它们具有相同或相似的矿物共生组合（黄铁矿－方铅矿－闪锌矿－黄铜矿－赤铁矿，自然金）及成矿元素共生组合（Au-Cu-Pb-Zn-Fe)，成矿作用均具有多期，多阶段特征，均为受胶莱盆地形成初期富Au和C有机矿源层控制，后经构造－岩浆热液及地下热液作用的沉积改造型金矿床。 相似文献
6.
7.
金矿床主要矿物标型特征研究综述 总被引：7，自引：1，他引：7
总结了金矿床中金矿物、黄铁矿、方铅矿、闪锌矿及黄铜矿等金属矿物和石英、碳酸盐矿物、云母类矿物及金红石等非金属矿物的产状，晶体形态、比重、硬度、颜色、反射率、导电性、热发光性等物理性质，谱学特征以及化学成分特征。从中提取出不同类型金矿床成因信息，含矿与非矿矿物特征以及判定金矿化程度、矿床规模和矿体剥蚀程度的指标。 相似文献
8.
四川石棉西部碳酸盐岩中的金矿床产于泥盆系中统,受层间蚀变破碎带控制。围岩蚀变类型有硅化、碳酸盐化和绢云母化。矿石矿物组分为黄铁矿、黝铜矿、黄铜矿、方铅矿、闪锌矿和Ａｕ－Ａｇ系列矿物,具Ａｕ－Ｃｕ－Ａｇ－Ｐｂ－ＳＡｓ－Ｓｂ－Ｂｉ的元素组合,并一定的垂直分带规律。其成因类型为地下热卤水型。矿床受地层、岩性和断裂的控制明显。并阐明了金矿床的成矿过程和勘查准则。 相似文献
9.
10.
山东省平度市大庄子金矿区黄铁矿、方铅矿与金的共生关系研究 总被引：1，自引：0，他引：1
通过对山东省平度市大庄子金矿区黄铁矿、方铅矿三个蚀变阶段特征研究,发现金矿化主要发生在第二阶段,强烈的石英-黄铁矿-碳酸盐化与金矿化的关系最为密切。金多数以包体的形式赋存于黄铁矿等金属硫化物中,并且在黄铁矿、方铅矿、闪锌矿等矿物共同产出时更有利于金的富集。研究认为石英和黄铁矿组合以及黄铁矿、黄铜矿、方铅矿、闪锌矿的组合可作为金的富集指示性矿物组合,伴生矿物之中方铅矿含金性最好。方铅矿、黄铜矿、闪锌矿和磁黄铁矿呈细脉状、网脉状、斑杂状产于含金石英脉和团块状黄铁矿的裂隙中,研究发现细脉状较团块状黄铁矿含金性要好。 相似文献
11.
金窝子金矿属于岩浆热液型金矿床,金矿化类型有石英脉型和蚀变糜棱岩型.金多呈独立金矿物形式出现,少许呈分散状,以银金矿为主,次为自然金,平均成色782.金矿物以粒间金、裂隙金、连生金和包体金等形式嵌布于黄铁矿、石英、方铅矿及闪锌矿等主要载金矿物中,且黄铁矿、石英较金属硫化物中占优势,黄铜矿中未见金矿物.金矿物形态各样,粒度以中细粒为主.金矿物特征反映出本区金矿床的成矿物质主要来源于变质岩,成矿作用与华力西、燕山期中酸性侵入岩有关.这与地质地球化学研究所获得的矿床成因认识相一致. 相似文献
12.
V. F. Proskurnin G. A. Palyanova N. S. Karmanov A. A. Bagaeva A. V. Gavrish B. S. Petrushkov 《Doklady Earth Sciences》2011,441(2):1661-1665
Uytenbogaardtite has been observed when examining the ores of the Konechnoe gold ore occurrence, West Taimyr, which is the
first find for the entire Taimyr-Severnaya Zemlya region. It is associated with native gold (fineness 520–560‰), pyrite, and
sphalerite. Sphalerite is characterized by Fe, Cd, Ag, and Cu impurities. Zinc is present in siderite. In the ores of the
Konechnoe ore occurrence, there is also native gold of the early generation with sphalerite, the latter containing chalcopyrite
lamellae and being in association with arsenopyrite, pyrite, and galena. The peculiar compositions of microinclusions and
impurities in sphalerite and other minerals and the presence of accessory minerals, such as monazite and apatite, reflect
the specific metallogenic and geochemical characteristics of the Minina-Bol’shevik structural-metallogenic zone and serve
as indicators of the potential of the North Taimyr area in terms of gold, silver, zinc, copper, lead, cadmium, strontium,
thorium, and lanthanides. 相似文献
13.
胶东大庄子金矿床地质特征与成因探讨 总被引：5，自引：1，他引：5
研究表明大庄子金矿床受NNE走向的层间滑动断层及其伴生张性裂隙的控制 ,分别产出蚀变破碎带型和石英脉型两种类型的矿体。蚀变破碎带型矿体围岩蚀变发育 ,自下而上分为 :钾长石化带 ,黄铁矿化、绢英岩化及黄铁绢英岩化带 ,绢英岩化和碳酸盐化带。矿石中含丰富的黄铁矿、方铅矿、闪锌矿和黄铜矿等多金属硫化物。金以银金矿为主 ,次为金银矿 ,多被金属硫化物包裹或存在于裂隙中 ,少量以自然金分散其中。黄铁矿中金含量高达 40× 10 - 6 ～ 960× 10 - 6 。综合分析表明 ,该矿床与胶东其他金矿床成矿背景一致 ,形成于陆内俯冲中_晚期的拉张环境。 相似文献
14.
利用电子探针研究甘肃陇南赵家庄金矿载金矿物特征 总被引：1，自引：1，他引：0
应用偏光显微镜与电子探针相结合的手段是研究载金矿物的主要方法。本文采用镜下鉴定和电子探针分析技术,对赵家庄金矿中载金矿物含量、形态特征及其与其他矿物的空间关系开展研究,并对载金矿物进行定性和定量分析,探寻具有找矿意义的载金矿物和总结标志矿物特征。结果表明:研究区金矿石中主要载金矿物为黄铁矿,少量为黄铜矿、闪锌矿,这些载金矿物中Au含量依次为:细晶黄铁矿粗晶黄铁矿草莓状黄铁矿黄铜矿。不同时期的黄铁矿(粗晶黄铁矿、细晶黄铁矿、草莓状黄铁矿)中Au的分布均匀,但存在差异性,主要表现为细晶黄铁矿和草莓状黄铁矿中的Au含量较高(平均含量0. 14%～0. 18%),这种现象表明此类矿物为构造热液期形成,金易富集。Au以两种形式存在,一种是"可见金"包裹于脉石矿物中,或以裂隙金的形式嵌布在矿物晶隙及裂隙中;另一种是"不可见金"以纳米级颗粒金的形式存在于载金矿物中,也是Au的主要存在形式。本研究为后期矿床的成因、成矿过程和成矿机理研究提供了佐证,同时易于根据含金矿物的特征选择合适的选冶方法。 相似文献
15.
Abstract. Intrusion‐related gold deposits are widely distributed within the North China craton or along its marginal fold belts. Presently, about 200 individual intrusion‐related gold deposits (prospects) have been discovered, among which Yuerya, Anjia‐yingzi, Linglong, Jiaojia, Chenjiazhangzi, Qiyugou, Jinjiazhuang, Dongping, Hougou, Huangtuliang, Guilaizhuang, Wulashan and Donghuofang are the most important ones. In general, the intrusion‐related gold deposits can be classified into three major groups according to their host rocks: (1) hosted by or related to felsic intrusions, including (la) calc‐alkaline granitoid intrusions and (lb) cryptoexplosion breccia pipes; (2) related to ultramafic intrusions, and (3) hosted by or related to alkaline intrusions. The first group contains the Yuerya, Anjiayingzi, Linglong, Jiaojia, Chenjiazhangzi and Qiyugou gold deposits. Gold mineralization at these deposits occurs within Mesozoic Yanshanian calc‐alkaline granitoid intrusions or cryptoexplosion breccia pipes as gold‐bearing quartz veins and replacement bodies. Pyrite, galena, sphalerite, chalcopyrite, native gold and electrum are major metallic minerals. The Jinjiazhuang deposit belongs to the second group, and occurs within Hercynian diopsidite and peridotite as quartz veins and replacement bodies. Pyrite, marcasite, arsenopyrite, native gold and electrum are identified. The third group includes the Dongping, Hougou, Huangtuliang, Guilaizhuang, Wulashan and Donghuofang deposits. Gold mineralization at these deposits occurs predominantly within the Hercynian alkaline intrusive complexes as K‐feldspar‐quartz veins and replacement bodies. Major metal minerals are pyrite, galena, chalcopyrite, tellurides, native gold and electrum. All these pyrite separates from Hercynian and Yanshanian intrusions or cryptoexplosion pipes associated with the gold deposits show a broad range in δ34S value, which is overall higher than those Precambrian rocks and their hosted gold deposits. For the alkaline intrusion‐related gold deposits, the δ34S values of the sulfides (pyrite, galena and chalcopyrite) from the deposits increase systematically from orebodies to the alkaline intrusions. All of these intrusion‐related gold deposits show relatively radiogenic lead isotopic compositions compared to mantle or lower crust curves. Most lead isotope data of sulfides from the gold ores plot in between the fields of the intrusions and Precambrian metamorphic rocks. Data are interpreted as indicative of a mixing of sulfur and lead from magma with those from Precambrian metamorphic rocks. Isotopic age data, geological and geochemical evidences suggest that the ore‐forming materials for the intrusion‐related gold deposits were generated during the emplacement of the Hercynian or Yanshanian intrusion. The calc‐alkaline or alkaline magma may provide heat, volatiles and metals for the intrusion‐related gold deposits. Evolved meteoric water, which circulated the wall rocks, was also progressively involved in the magmatic hydrothermal system, and may have dominated the ore fluids during late stage of ore‐forming processes. Therefore, the ore fluid may have resulted from the mixing of calc‐alkaline or alkaline magmatic fluids and evolved meteoric water. All these intrusion‐related gold deposits are believed to be products of Hercynian or Yanshanian calc‐alkaline and alkaline igneous processes along deep‐seated fault zones within the North China craton or along its marginal belts. 相似文献
16.
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. 相似文献
17.
位于华北克拉通南缘的小秦岭地区是我国仅次于胶东的大型金矿床集中区,但金矿床的成矿物质来源及成因问题一直存在较大争议.以华北南缘小秦岭矿集区东桐峪金矿床中的黄铁矿作为研究对象,在黄铁矿显微结构研究的基础上利用LA-ICP-MS对黄铁矿的微量元素进行原位分析,为进一步认识东桐峪金矿床及区内其他同类型矿床的成因提供新的资料和制约.东桐峪金矿床的黄铁矿从早到晚依次划分为3个世代(PyⅠ、PyⅡ和PyⅢ).PyⅠ主要形成于粗粒黄铁矿-石英阶段,颗粒粗大且自形程度高,呈星点状或斑点状赋存于乳白色石英脉中.PyⅡ主要形成于石英-中细粒黄铁矿阶段,呈半自形-他形结构且裂隙发育,常被晚期石英、多金属硫化物、自然金等矿物充填.PyⅢ主要形成于多金属硫化物阶段,常呈他形粒状结构与黄铜矿、方铅矿及闪锌矿等硫化物密切共生.LA-ICP-MS分析结果显示,PyⅠ中As平均含量为16.63×10-6,Au、Ag和Te含量较低且常位于检测限以下;相较而言,PyⅡ中As含量稍低,而Au、Ag和Te含量略高(其中Au含量为0.10×10-6~0.59×10-6);PyⅢ中Au、Ag和Te含量差异较大且显著升高,其中Au、Te含量最高可达35.58×10-6和79.79×10-6,而As含量较低且大部分数值低于检测限;不同世代黄铁矿的Co/Ni比值基本上都大于1,且PyⅢ的Co、Ni含量和Co/Ni比值明显低于PyⅡ和PyⅠ.以上结果表明,东桐峪金矿床的载金矿物黄铁矿中As的含量很低,金的富集与As无关;不同世代的黄铁矿中Au、Ag和Te之间存在显著且稳定的线性正相关关系,暗示金矿化与Te关系密切.另外,第3世代黄铁矿(PyⅢ)中Au、Ag及Te存在显著富集,指示Te(而不是As)在金和银的迁移、搬运、富集、沉淀等过程中具有重要作用.华北克拉通南缘小秦岭地区晚中生代大规模的金成矿作用及金矿床中普遍存在Te-Au-Ag矿物,且黄铁矿中As含量低、Te含量高等特征,暗示该区金矿床的成矿物质/成矿流体可能来自深部岩浆的脱挥发分或地幔脱气作用,而与区域变质作用的关系不大. 相似文献
18.
Gold deposits at El Sid are confined to hydrothermal quartz veins which contain pyrite, arsenopyrite, sphalerite and galena. These veins occur at the contact between granite and serpentinite and extend into the serpentinite through a thick zone of graphite schist. Gold occurs in the mineralized zone either as free gold in quartz gangue or dissolved in the sulfide minerals. Ore-microscopic study revealed that Au-bearing sulfides were deposited in two successive stages with early pyrite and arsenopyrite followed by sphalerite and galena. Gold was deposited during both stages, largely intergrown with sphalerite and filling microfractures in pyrite and arsenopyrite.Spectrochemical analyses of separated pyrite, arsenopyrite, sphalerite and galena showed that these sulfides have similar average Au contents. Pyrite is relatively depleted in Ag and Te. This suggests that native gold was deposited in the early stage of mineralization. Arsenopyrite and galena show relatively high concentrations of Te. They are also respectively rich in Au and Ag. Tellurides are, thus, expected to be deposited together with arsenopyrite and galena. 相似文献
19.
The genesis of the slab window-related Arzular low-sulfidation epithermal gold mineralization （eastern Pontides, NE Turkey） 总被引：1，自引：0，他引：1
The Arzular mineralization is one of the best examples of epithermal gold deposits in the eastern Pontides orogenic belt.The mineralization is hosted by the subduction-related basaltic andesites and is mainly controlled by E-W and NE-SW trending fracture zones.The main ore minerals are galena, sphalerite,pyrite.chalcopyrite.tetrahedrite and gold.Homogenization temperatures of fluid inclusions are between 130 and 295℃ for quartz and between 90 and 133℃ for sphalerite.Sulphur isotope values obtained from pyrite,galena and sphalerite vary between 1.2‰ and 3‰.indicating that sulphur belongs to magmatic origin and was derived from the Lutetian non-adakitic granitic intrusions in the region.Oxygen isotope values are between 15.0‰ and 16.7‰ and hydrogen isotope values are between -87‰ and -91‰ The sulphur isotope thermometer yielded temperatures in the range of 244-291℃ for the ore formation.Our results support the hypothesis that the Arzular mineralization is a low-sulfidation epithermal gold deposit associated with non-adakitic subduction- related granitic magmas that were generated by slab window-related processes in a south-dipping subduction zone during the Lutetian. 相似文献