Minor elements in sphalerite and galena from Binnatal

The trace element contents of 23 sphalerites and galenas from Binnatal, Switzerland, have been determined. Most of these samples have been previously studied in respect to lead and sulphur isotope abundances. Coloration of sphalerites — varying from yellow to black for nearly identical iron contents — seems to be strongly influenced by the manganese content. A linear relationship between sulphur isotope composition and copper content in sphalerites was found. Trace elements in galenas show a significant inverse relationship between silver and copper. With the determination of the bismuth content, it is possible to distinguish several galena types; a similar grouping has been found by lead isotope determinations. The results of the trace analyses are discussed in connection with the occurrence of a large number of very rare and special Pb-As-sulphosalt minerals in the Binnatal dolomites.     

Galvanic interactions between galena–sphalerite and their reactivity

The galvanic effect between the main associated mineralogical phases in a mineral sphalerite concentrate was evaluated using an alternative methodology. Comparative voltammetric studies were performed between high purity galena mineral (94.65%) and sphalerite concentrate (content of 78.11% sphalerite, ZnS; 13.64% galena, PbS; 0.57% chalcopyrite, CuFeS₂; 0.41% cadmium sulfide, CdS; and 0.11% arsenopyrite, FeAsS) using carbon paste electrodes (CPE) in order to identify galvanic interactions that affect their reactivity. The electrolyte was an aqueous solution of 0.1 M NaNO₃ (pH 6.5). The results showed that, in sphalerite concentrate, the electrochemical reactivity of the galena was diminished and displaced to more positive potentials with respect to the high purity galena mineral response. This behavior can be attributed to the galvanic protection offered by the sphalerite on the galena, thereby avoiding its free oxidation. On the other hand, sphalerite oxidation was diminished by the formation of a passive products film that is dissolved to more positive potentials which provokes oxidation of other minerals like CuFeS₂, (Zn,Cd)S and FeAsS present in a minor proportion in the sphalerite concentrate.     

Arsenite adsorption on galena (PbS) and sphalerite (ZnS)

Arsenite, As(III), sorption on galena (PbS) and sphalerite (ZnS) was investigated as a function of solution composition and characterized using X-ray absorption spectroscopy (XAS). Adsorption conformed to a Langmuir isotherm except at the highest surface loadings, and it was not strongly affected by changes in ionic strength. Arsenite sorbed appreciably only at pH > ∼5 for PbS and pH ∼4.5 for ZnS, behavior distinct from its adsorption on other substrates. Arsenite adsorption on PbS and ZnS resulted in the conversion from As-O to As-S coordination. Arsenite does not adsorb through ligand-exchange of surface hydroxyl or sulfhydryl groups. Rather, it forms a polynuclear arsenic sulfide complex on ZnS and PbS consistent with the As₃S₃(SH)₃ trimer postulated by Helz et al. (1995) for sulfidic solutions. This complex was unstable in the presence of oxidizing agents and synchrotron light—it quickly converted to As(V), which was largely retained by the surface. These data illustrate the complexity of As(III) adsorption to even simple sulfide minerals.     

Determination of major and trace elements in sphalerite using laser ablation double focusing sector field ICP-MS

The analytical performance of laser ablation (LA) for the determination of Co, Fe, Cd, Ag, Mn, Cu and S in sphalerite was evaluated using double focusing sector field inductively coupled plasma mass spectrometry (ICP-SFMS). Samples were collected from Zinkgruvan, situated in the south central Sweden. The use of Zn for internal standardisation, together with correction for FeS impurities in sphalerite, allows straightforward quantification without using external methods for the determination of the actual Zn content. LA–ICP-SFMS results were compared with data obtained by conventional pneumatic nebulisation introduction of sample solutions following acid digestion. Good agreement between the two methods was obtained for homogeneously distributed elements. For the majority of the elements under consideration, LA–ICP-SFMS precision was better than 10% RSD.     

An atomic level study of rhenium and radiogenic osmium in molybdenite

Local atomic structures of Re and radiogenic Os in molybdenite from the Onganja mine, Namibia, were examined using X-ray absorption fine structure (XAFS). Rhenium L_III-edge X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) show that the oxidation state of Re, the interatomic distances between Re and the neighboring atoms, and the coordination number of Re to S are very similar to those of Mo in molybdenite. The results confirm that Re is present as Re(IV) in the Mo site in molybdenite.Measurement of L_III-edge XANES and EXAFS of a minor concentration (8.55 ppm) of radiogenic Os was accomplished in fluorescence mode by removing the interfering X-rays from Re and other elements using a crystal analyzer system. The data indicate that the oxidation state of radiogenic Os is Os(III) and Os(IV) and clearly different from Os(II) in natural sulfide minerals, such as OsS₂ (erlichmanite). XANES data also suggest that radiogenic Os does not form a secondary Os phase, such as OsS₂ or Os metal, in molybdenite.EXAFS of radiogenic Os was successfully simulated assuming that Os is present in the Mo site in molybdenite. The data are consistent with the XANES data; Os does not form Os phases in molybdenite. The EXAFS simulation showed that the interatomic distance between Os and S is 2.27 Å, which is 0.12 Å smaller than the distances of Re-S and Mo-S (2.39 Å) in molybdenite. Similar valences and ionic sizes of Re and Mo in molybdenite support the fact that large amounts of Re can be incorporated into the Mo site as has been observed in previous studies, whereas the different properties of Os compared to Mo and Re suggested here support much lower abundance of common Os in molybdenite. This makes molybdenite an ideal mineral for the Re-Os geochronometer as shown in many studies. However, the shorter distance between radiogenic Os and S compared to those of Re-S and Mo-S in molybdenite suggests that the radiogenic Os has a smaller ionic size than Re(IV) and Mo(IV). Furthermore, Os may be partly present as Os(III). Smaller and lower charge Os can diffuse faster than larger and higher charge Re in molybdenite at a given set of conditions. Hence, our study provides an atomic-level explanation for the high mobility of Os compared to Re, which has been suggested by earlier workers using laser ablation ICP-MS.     

Partition of cadmium and manganese between coexisting sphalerite and galena from some Japanese epithermal deposits

Sphalerites from Japanese epithermal Pb-Zn vein-type deposits, namely, Yatani, Oizumi and Hosokura, contain 2900–3400 ppm cadmium and 760–2100 ppm manganese. And galenas from the same deposits contain cadmium and manganese 19.2–26.9 ppm and 7.8–218.3 ppm, respectively. The temperatures, evaluated from the partition of cadmium between coexisting sphalerite and galena, are consistent within a total range of 150°C at maximum within an individual deposit. No systematic change with depth can be observed at the Shoko-hi vein, Hosokura mine and Hompi vein, Yatani mine. In several samples, the temperatures obtained from the partition of cadmium have been compared with those obtained from sulfur isotope fractionations. Iron content in sphalerite coexisting with pyrite indicates that the deposition of ore minerals at these deposits may have taken place from ore-forming solutions in which H₂S or HS^– was the predominant dissolved sulfur species, and the solutions may have been free from in situ oxidation or reduction.     

煤中黄铁矿的铼-锇同位素含量及其地质意义

采用Carius管溶样方法,通过热电离质谱对淮北煤田煤中黄铁矿样品的Re、Os含量及其同位素进行了测定,得出黄铁矿样品中Re和Os含量分别为1·22~1·29ng/g和0·0046~0·0054ng/g。对两个样品同位素定年测定得出,其年龄值分别为(73·9±3·2)Ma和(33±9)Ma,两个样品的年龄相差约258~286Ma。含量和同位素年龄差值表明两个样品是不同时代形成的黄铁矿。Re-Os同位素体系比值揭示黄铁矿所赋存的地质体受到来自地壳物质的显著混染。另外,γOTs参数也证实了这一点。该参数分别为+17和+18,表明了有富含Re母体的地壳物质的加入,这为煤中Re-Os含量及地质理论研究提供了参考资料。     

The selective flotation of galena from sphalerite with special reference to the effects of particle size

The selectivity of galena flotation from a synthetic mixture with sphalerite and quartz and from a typical Broken Hill ore has been determined. It was found that the selectivity was limited by the relative flotabilities of coarse galena and sphalerite of intermediate sizes. The use of split conditioning in the preparation for flotation resulted in significant improvements in lead-zinc selectivity for both samples. By contrast the use of conventional zinc depressants in the flotation of the ore resulted in only slight changes in the behaviour of the minerals and had no discernible effect on the selectivity.     

Trace elements in galena and sphalerite and their geochemical significance in distinguishing the genetic types of Pb-Zn ore deposits

This paper deals with the trace elements Ag, Sb, Bi in galens and Fe, Mn, Cd, Se, Te, Ga and In in sphalerite from 60 Pb-Zn deposits in China and other countries. The contents of the selected trace elements and their ratios show regular variations from one type of Pb-Zn deposits to another. These elements or their ratios are plotted onto Pb-lnAg, lnSb-lnBi, lnGa-lnIn, Fe-Cd, Fe-Cd-Mn and Zn/Cd-Se/Te-Ga/In diagrams. On the basis of these diagrams, the deposits associated with magmatism(type I), those associated with volcanism(type II), the sedimentary-reformed deposits (type III) and sedimentary-metamorphic deposits(type IV) can be well distinguished. Types I and III have the definite fields in all the diagrams. Types II and IV also have their own fields in lnGa-lnIn and Zn/Cd-Se/Te-Ga/In diagrams. The author considers that these diagrams are applicable to distinguishing the genetic types of Pb-Zn deposits.     

Geothermometry based on fractionation of Mn and Cd between coexisting sphalerite and galena from some carbonate-hosted sulfide deposits in India

Geothermometry based on the fractionation of Mn and Cd between coexisting sphalerite and galena from concordantly banded, strata-bound ores and younger vein ores of Rajpura-Dariba, Zawar, and Bandalamottu has been attempted. Different fractionation trends for the banded and vein ores in the same deposit at Rajpura-Dariba indicate different thermal regimes of final equilibration for the two varieties of ores. In contrast, a single trend incorporating both types of ores is suggestive of isothermal conditions of final equilibration for the banded and vein ores at Zawar. Unrealistically high temperatures obtained for the vein ores of Bandalamottu suggest equilibrium in the sphalerite-galena aggregates of this deposit was not attained. Thermometric data from Mn and Cd fractionation are compared with other independent geothermometric determinations obtained from fluid inclusion homogenization studies and based on phase equilibria. It has been found that, in general, the Cd-fractionation temperature (T_Cd) is a more reliable geothermometer than the Mn-fractionation temperature (T_Mn). This presumably may be due to the susceptibility of aqueous Mn species to subtle changes in in the ore fluid and consequent heterogeneity in Mn concentration in sphalerite, thus affecting the distribution coefficient. The investigation also suggests that T_Cd becomes increasingly more dependable when the ores are metamorphosed and reequilibrated at higher grades of metamorphism.     

CP-MS测定饮用水中Fe的方法

通过实验确定了ICP-MS检测饮用水中Fe的质量质量浓度方法。检测方法的检出限(DL)和精密度(RSD)分别达到3.29ng/mL和4.49%(n=12)。     

电感耦合等离子体质谱法(ICP-MS)测定紫菜、螺旋藻中的硒

应用电感耦合等离子体质谱法测定了紫菜、螺旋藻中硒。采用微波消解,直接测定。其方法检出限低,准确度好。     

感耦等离子体质谱法直接测定碳酸盐岩中超痕量稀土元素

探讨了等离子体质谱（ＩＣＰ－ＭＳ）测定碳酸盐岩痕量稀土元素效应及稀土元素间干扰,要用模拟碳酸盐岩样品中稀土元素天然组成比值的校正溶液,对稀土元素间的干扰具有明显的抑制作用,利用＾１１５Ｉｎ－＾１０３Ｒｈ双内标校正系统,有效地抑制分析信号的动态漂移,建立了碳酸盐岩中超痕量稀土元素的ＩＣＰ－ＭＳ分析方法,方法检出限为（０．１～１．２６）ｎｇ／ｇ,ＲＳＤ≤１０％（ｎ＝５）,用碳酸盐岩标准物质ＧＢＷ０７１０８和碳酸盐岩管理样分析验证,测定结果与标准值符合。     

等离子体质谱法分析原油中超痕量稀土元素的研究

报道了用等离子体质谱仪测定原油中超痕量稀土元素的研究工作。试验了不同地区原油样品前处理的各种方法,确定以浓Ｈ２ＳＯ４为炭化剂,克服了原油样品炭化过程中试样膨胀外溢和跳溅诸问题。考察了共存元素的干扰情况,采用Ｒｅ内标补偿测定信号的影响。各稀土元素的检出限在０．９～１６．１ｎｇ／Ｌ,标准加入回收率为９９．８％～１０７．７％,方法精密度好,ＲＳＤ（ｎ＝１０）为４．３６％～１６．５３％。该方法已成功地用于不同地区原油样品的测定。     

ICP-MS测定生物样品中的微量金属元素

采用SP-60型恒压消解罐消解生物样品,用ICP-MS测定8种金属元素(Mn、Zn、Pb、La、Ce、Mo、Cr和Fe)的质量分数。依据分析结果,比较了消解程序的效果。结果表明,由10.0 mLHNO3对生物样品具有很好的消解能力,各元素的测定值与推荐值相符。     

Origin of galena and sphalerite mineralization in the Koru Volcanics,Biga Peninsula,Turkey: insights from MELTS modelling and SUPCRT calculations

Seismic and gravity data have disclosed correlations between the structure of the major folded belts with the surface of the basaltic layer and the Moho. The major structural elements of the Greater Caucasus province are reviewed, though with all too generalized maps for reference. These structures are reviewed in the light of their evolution in three stages: the first ending in the Medial-Late Jurassic, the second ending in the Middle Paleogene, and the third occupying the Oligocene-Neogene-Quaternary periods. A major synclinorium and anticlinorium of long duration are postulated. The granite layer is summarized in an isopachous map. This is correlated with a contour map of the Moho. Inheritances of earlier geosynclinal cycles (Hercynian). The primary geosyncline is related to planetary rifts. The thickest part of the crust is centered on the meganticlinorium in the Alpine structures of the Caucasus. Formation of folds, foredeeps, and folding after sedimentation is related to development of the granite layer during continental evolution. Deep-seated piercement of the granite into the cover in the axial portion is indicated. The observable seismicity is also correlated with evolution of the granite layer.--B. N. Cooper.     

Determination of Bromine and Iodine in Twenty-three Geochemical Reference Materials by ICP-MS

Trace amounts (from nanogram to microgram levels) of bromine and iodine were determined by inductively coupled plasma-mass spectrometry (ICP-MS) in twenty-three geochemical reference materials issued by the GSJ, USGS, IAEA etc. The pyrohydrolysis technique was used to separate bromine and iodine from samples analysed in the form of powder. The accuracy and precision of the experimental values were assessed by the comparative analysis of well established reference materials such as USGS AGV-1, BCR-1 and IGGE GBW07312. The measured values agreed well with reported values within a 10% error range. We also report reliable new data for these elements in these geochemical reference materials.     

Abundances and isotopic compositions of rhenium and osmium in pyrite samples from the Huaibei coalfield,Anhui, China

Two pyrite samples from the Shihezi Formation (Lower Permian), Huaibei coalfield, Anhui, China, have been analyzed for abundances and isotopic compositions of rhenium and osmium using negative thermal ion mass spectrometry. The Re–Os ages of the pyrites are 64.4 and 226 Ma, which are younger than the formation age of the coal seam. The pyrite samples may consist of pyrite formed at various stages during the history of coal formation. The γ_Os values of the two pyrite samples are + 17 and + 18, respectively. Such high γ_Os values are reported for the first time for recycles crustal materials from a sedimentary basin.     

电感耦合等离子体质谱直接测定冰芯样品中痕量铅

利用电感耦合等离子体质谱仪对冰芯样品中超痕量Pb进行了直接测定。确定了测定溶液中浓度为ng/L级Pb的最佳仪器参数，载气流速、进样速度等与灵敏度之间的关系,浓度和扫描参数对分析精度的影响。仪器对Pb的质量浓度在20～100ng/L的分析精度(RSD，n=3)＜10%,标准加入回收率在85%～115%，检测下限为0.62ng/L，并给出了采自可可西里马兰冰川M3冰芯中Pb的分析结果。     

微波消解-电感耦合等离子体质谱法测定高岭土中10种微量元素

高岭土作为重要的铝硅酸盐,其微量元素的含量决定着高岭土产品的性能指标.高岭土的三种国家标准物质成分GBW03121、GBW03122、GBW03122a中均未含有As、Sb等10种微量元素的标准值,在高岭土的检测中只能采用近似的岩石标准物质作为监控物质,对高岭土组分的准确分析有一定影响.本文通过微波消解技术,对比了硝酸...