黄铁矿成因形态学

1981—1986年,我们对玲珑金矿、夏甸金矿、栖霞金矿和三山岛金矿的黄铁矿晶体形态进行了野外和室内研究。其中,晶形统计2495粒,晶体测角300粒,用扫描电子显微镜对60粒晶体进行了微形貌研究。对四个金矿床的研究表明,黄铁矿晶体单形以立方体{100}最常见,出现频率为92.47%,其次为五角十二面体{hko}(其形号包括{210}、{310}、{410}、{810}、{830}、{910}及{11,1,0})出现频率为57.27%;其次为八面体{111},出现频率为16.88%,较少见的为偏方复十二面体{hkl}(其形号包括{321}、{421}、{10,6,5),{18,24,25)及{34,     

黄铁矿成因特征的研究

黄铁矿是最常见的金属矿物。研究它的标型特征、光学及物理性质、晶胞参数及杂质元素的分布特征等,对于解决矿床的成因问题无疑格外重要。在通常条件下黄铁矿固溶体范围很窄,性质上只存在着微小的差异。但运用现代研究方法还是有可能查明一些成因特征的。本文想着重指出的,是晶形、晶格上的微小变化、杂质元素的分布以及有关的控制因素。     

塞浦路斯黄铁矿矿床的成因

黄铁矿矿床的地质概况塞浦路斯岛的中心由特罗多斯火成杂岩体组成,其边部为层状沉积岩.主要的黄铁矿矿床即产于火成杂岩体与上覆沉积物的接触带上或其附近.最下部的沉积层为佩拉佩德希层,该层局部含有火山碎屑-沉积岩,但总的看来,它以独立的单位发育.主要的黄铁矿矿床与该层密切伴生,据推测,二者具有相同的成因.分类与说明浸染状、块状、脉状、洞穴和(或)空隙     

煤中黄铁矿的成因研究

本文在系统地研究四川晚二叠世高硫煤中黄铁矿矿物学的基础上，运用微区电子探针、中子活化、Ｘ光电子能谱和硫同位素等多 种方法综合地研究煤中黄铁矿的结构、成分、价态及同位素等成因标型特征，对黄铁矿标型特征进行了成因探讨，有效地判别了成岩期形成的Ｉ型脉状黄铁矿及后生热液Ⅱ型脉状黄铁矿。同时提出直接沉淀系列（自形晶→集合→聚晶）和复杂成因（微粒、莓粒→圆球→结核→团块）等两大类成因演化模式。它不仅对不同类型     

塔里木盆地奥陶系碳酸盐岩中黄铁矿的成因

塔里木盆地下古生界(特别是奥陶系)碳酸盐岩地层中常见大量自生黄铁矿存在于碳酸盐岩、裂缝和溶蚀孔洞以及岩溶角砾和岩溶孔洞充填砂泥碎屑物质中。根据产状和硫同位素值,黄铁矿可分为两组,一组的δ34S值范围为-25.7‰～-4.7‰,平均为-17.6‰,为细菌硫酸盐还原作用(BSR)成因,发生在碳酸盐岩被抬升至地表接受岩溶改造的时期;另一组的δ34S值范围为+11.2‰～+31.3‰,平均为21.8‰,是受岩浆作用的影响,在热化学硫酸盐还原作用(TSR)下形成的。通过分析认为塔里木盆地下古生界地层天然气中较高含量的H2S主要是TSR作用的产物。     

黄铁矿型矿床的地质与成因

据外刊报道,在25届国际地质会议上,与会学者讨论了黄铁矿型矿床的成因.许多地质学家把这种矿床叫做与火山活功伴生的层状矿床;没有一篇报告认为此类矿床是与花岗岩岩浆作用有亲缘关系.澳大利亚的斯坦顿划分了四个火山活动期,①太古代,只有少数与苦橄岩火山活动有关的"汤普松"式黄铁矿型矿床产出.②元古代,如澳大利亚的布罗肯-希尔、茫特-艾萨.这类矿床,成因上与从玄武岩到     

胶状黄铁矿成因类型与鉴别特征

胶状黄铁矿广泛分布在多种地质体中, 对其成分标型进行深入研究可以获得大量成因信息。通过分析胶状黄铁矿的矿物形态、晶体结构, 并利用Fe-S、Co-Ni、S-Se、Se-Te和δ34S图解, 对胶状黄铁矿的组成特征进行对比研究, 可以有效区分其成因类型。沉积成因的胶状黄铁矿多呈球形、椭球状和团块状的聚合形态, Co/Ni＜l, S/Se＞2.5×104, Se/Te＜0.45, δ34S值变化范围较宽(-13‰~+13‰), 显微镜下常具有鲕粒替代的假象结构。热液成因的胶状黄铁矿多呈不规则的脉状, 微观结构常具有一定的定向性, 1＜Co/Ni＜5, S/Se＜2.5×104, Se/Te＞0.45, 其中岩浆热液成因的胶状黄铁矿Co/Ni、S/Se和Se/Te均高于变质热液成因, δ34S值范围较窄, 通常集中于0~5‰。沉积成因的胶状黄铁矿成核和晚期环带生长的过程主要发生在厌氧的早期成岩阶段, 在硫酸盐还原菌的作用下结晶出纳米粒级的微晶黄铁矿, H2S存在的厌氧环境中, Cu、Zn、Mo等金属元素以硫化物固溶体的形式进入结晶的纳米级黄铁矿颗粒而富集。而热液成因的胶状黄铁矿可作为一种载体矿物, Au、As等元素按层状-岛状生长模型赋存在胶状黄铁矿的生长环带中; 中低温条件下可相变为磁黄铁矿等矿物, 进一步促进Cu等元素沉淀。     

平顶山金矿床黄铁矿晶体形态学研究及其找矿意义

平顶山金矿床的黄铁矿晶体形态研究表明，产于不同地质体的黄铁矿晶体表面微形貌有较大的差异，这种差异反映了黄铁矿结晶时的环境特点，不同时期形成的黄铁矿在晶体形态和粒度上是有差异的，并且含金性亦不同，晶形好粒度大的黄铁矿含金性差，细粒它形的黄铁矿则含金性好。     

平顶山金矿床黄铁矿晶体形态学研究及其找矿意义

平顶山金矿床的黄铁矿晶体形态研究表明，产于不同地质体的黄铁矿晶体表面微形貌有较大的差异，这种差异反映了黄铁矿结晶时的环境特点。不同时期形成的黄铁矿在晶体形态和粒度上是有差异的，并且含金性亦不同，晶形好粒度大的黄铁矿含金性差，细粒它形的黄铁矿则含金性好     

太白庙金矿床黄铁矿晶体形态学研究及其找矿意义

陕西镇安太白庙金矿床黄铁矿晶体形态学研究表明,｛210｝晶形黄铁矿多产于成矿阶段的富矿地段,呈五角十二面体,亏硫富铁型,Co、Ni含量较低,As、Cu、Pb、Zn含量较高,热电导型属P型和N－P混合型（P）N）,包体成份明显较高,ao值较大,含金性较好,指示了金矿化的有利环境。     

黄铁矿单矿物分析

黄铁矿常规分析多采用单独取样,针对某些元素采用有关分析方法。因而手续较繁琐,需要样品量也大。为了简化分析流程,减少样品用量,经试验拟定了黄铁矿单矿物系统分析流程。其特点是在一分称样中通过阳离子交换树脂分离,使阴阳离子分成两部分。在含阴离子溶液中可测定硫、砷、硒、磷等元素;在含阳离子溶液中可测定铁、铜、     

黄铁矿表面的扫描隧道显微镜研究

为了探讨硫元素在煤中的赋存，对煤硫元素的主要载体黄铁矿的表面进行了扫描隧道显微镜研究，在硅油保护下得到了黄铁矿表面高分辨率图象。根据黄铁矿晶体结构的几何分析，所观察到的是黄铁矿｛２２０｝表面的原子分布，黄铁矿的能带结构资料及前人在这方面的研究均表明，用扫描隧道显微镜应首先观察到黄铁矿表面的铁原子，但作者首先观察到的却是黄铁矿表面的硫原子，此外，作者根据所获得的实验结果认为。无论是在｛２１０｝文向还     

黄铁矿晶体制备研究

本文介绍了目前黄铁矿晶体和薄膜的主要制备方法、制备条件参数及其产品特点,以及模拟天然黄铁矿生长的实验方法、条件参数和实验结果.指出应加强合成黄铁矿晶体生长理论研究,根据纳米线阵列、纳米晶线黄铁矿的优异物理、机械性能、天然黄铁矿晶须的矿物学特征和晶须材料的优越性能,认为今后黄铁矿晶须的应用有广阔的前景,合成黄铁矿研究工作值得关注.     

Pyrite dissolution in acidic media

Oxidation of pyrite in aqueous solutions in contact with air (oxygen 20%) was studied at 25°C using short-term batch experiments. Fe²⁺ and SO₄²⁻ were the only dissolved Fe and S species detected in these solutions. After a short period, R = [S]_tot/[Fe]_tot stabilized from 1.25 at pH = 1.5 to 1.6 at pH = 3. These R values were found to be consistent with previously published measurements (as calculated from the raw published data). This corresponds to a nonstoichiometric dissolution (R < 2) resulting from a deficit in aqueous sulfur. Thermodynamics indicate that S(−I) oxidation can only produce S_(s)⁰ and SO₄²⁻ under these equilibrium conditions. However, Pourbaix diagrams assuming the absence of SO₄²⁻ indicate that S₂O₃²⁻ and S₄O₆²⁻ can appear in these conditions. Using these species the simplest expected oxidation mechanism is

     

黄铁矿形貌标型特征的研究进展

黄铁矿是地壳中分布最广的硫化物矿物,常以立方体、八面体和五角十二面体等形态产出。研究表明,特定形貌黄铁矿在形成温度、压力、pH、Eh、氧逸度和硫逸度等方面差异明显,因此,黄铁矿形貌标型特征可以提供丰富的地质信息。目前,国内外黄铁矿形貌研究主要采用野外采样分析法和高温高压实验模拟两种方法。在常规的野外研究中,金矿床中黄铁矿形貌研究程度比较高,且将红外显微镜应用到黄铁矿内部结构分析和包裹体测温取得了突破性的成果,但是红外光难在高温条件下透过黄铁矿这一问题仍有待解决;室内高温高压实验研究主要通过合成黄铁矿的方法观察黄铁矿的生长习性,因研究方法的不同和实验技术条件的限制,目前得到的黄铁矿形貌标型尚不统一,黄铁矿形貌标型研究仍然需要突破和完善。     

Pyrite: physical and chemical textures

Pyrite may crystallize initially in forms as diverse as framboids or cubes depending upon the temperatures and pressures. Fluid-rich diagenesis or low-grade metamorphism clearly results in thorough recrystallization and the common formation of cubes. Once these have formed, the pyrite becomes much more refractory and retains many characteristics even in deposits which have undergone penetrative deformation. This is in strong contrast to the behavior of most of the accompanying sulfides, which often undergo ductile deformation, solid state or chemical remobilization, and annealing. Pyrite deforms sparingly until there is brittle failure; however, there may be significant pyrite corrosion and regrowth during metamorphism as the result of sulfur exchange with other minerals, especially pyrrhotite. Pyrite fabrics may also be significantly modified by pressure solution or Coble creep. Optical microscopic examination and electron microprobe chemical mapping of pyrites from a variety of mineral deposits, including several high-grade metamorphic ones, reveals that the pyrites frequently contain both physical and chemical textures that may be interpreted in terms of the depositional and the post-depositional history of the deposits. Inclusions of sulfides or other minerals reveal information on the timing of the crystallization or recrystallization of the pyrite; chemical mapping of elements such as Ni, Co, and As reveals information on the relative time of transport of these elements in the ore fluids. Received: 19 March 1997 / Accepted: 14 May 1998     

黄铁矿晶体形貌学研究进展

介绍了黄铁矿晶体形貌学、黄铁矿晶体表面微形貌学的研究内容;黄铁矿习见晶形在金矿床研究中的标型意义;近年来黄铁矿晶须形貌学研究进展;黄铁矿形貌的生长机制研究内容等.根据前人黄铁矿习见晶形研究成果的理论实践意义,分析认为纳-微米黄铁矿晶须形貌成因和生长地质过程研究,不仅在矿物结晶生长理论研究中有意义,在认知纳米矿物,理解纳米矿化现象等方面有启示,纳-微米黄铁矿晶须形貌学研究值得重视.     

Chert in the Iberian Pyrite Belt

Since lenses of chert are common within the volcano-sedimentary succession hosting the massive sulphide deposits of the Iberian Pyrite Belt (Spain and Portugal), we examined numerous chert occurrences, both petrographically and geochemically, to test their possible value for massive sulphide exploration. The chert is found at two main lithostratigraphic levels (upper and lower) that are also interpreted as massive-sulphide bearing. In both cases the chert is located at the top of acidic volcanic sequences or in the associated sediments; we have not been able to observe the relationships between massive sulphides and chert, but some of the large orebodies of the Province (Lousal, La Zarza, Tharsis, Planes-San Antonio body of Rio Tinto, Neves) are described as being locally capped by chert facies. Four main types are recognized among the chert and associated facies: (1) red hematitic chert?±?magnetite; (2) radiolarian and/or sedimentary-textured (conglomeratic) chert with hematite and/or Mn oxides; (3) pale sulphidic chert; (4) rhodonite and/or Mn carbonate?±?magnetite facies. In the Spanish part of the Province the radiolarian chert is confined to the upper level; the distribution of the other types appears to be haphazard. The hydrothermal origin of the South Iberian chert is shown by its high Fe-Mn and low Co-Ni-Cu contents. The presence of small positive Ce anomalies indicates a shallow marine environment (shelf or epicontinental sea), which is consistent with the volcanological and sedimentological data. The chert was emplaced below the sea floor through chemical precipitation and/or through alteration and replacement of the country rock, residual traces of which are ghost phenocrysts and high Al, Ti and rare earth contents. Macro- and microscopic relationships indicate that the oxide facies (hematite?±?magnetite) formed first, probably providing a protective insulating cover against the marine environment and enabling an evolution towards sulphide facies; a phase of Mn?carbonate and silicate + quartz?±?chlorite + sulphides appears to be even later. It was not possible, through discrimination, to isolate a chert that could be considered as representing a lateral marker of massive sulphides; moreover, both field observations and geochemical data seem to indicate a relative independence of this siliceous sulphide hydrothermal activity from the hydrothermal activity giving rise to the massive sulphides. Such is also indicated by the lead isotopic signature of the chert, which is appreciably more radiogenic than that of the massive sulphides; the lead enrichment in the sulphidic chert facies indicates the participation of a different source (sediments, sea water) from that of the massive sulphides. The hypothesis of an independent hydrothermal “chert” event can thus be envisaged, wherein the chert reflects submarine low-temperature hydrothermal activity that is most apparent during a “break” within the volcano-sedimentary succession and which may locally have competed with the high-temperature hydrothermal activity giving rise to the massive sulphides. The interest of the chert thus rests in its palaeodynamic significance, as a marker of periods of volcanic quiescence, and in its possible role as a protective insulating cap favourable to the deposition of massive sulphides.     

Surface Mineralogy of Oxidized Pyrite by Acidithiobacillus Ferrooxidans

Sulfide oxidation by microbial activities play an important role in the release of heavy metals. An important source of contamination and formation of AMD is the heavy metals convey to soil, rivulet and groundwater. Pyrite is a commonly sulfide minerals in mine wastes, so it is vitally to prove up the microbial oxidation process.