碱熔-标准物质法-电感耦合等离子体发射光谱(ICP-AES)法测定硅酸盐岩中10种主量元素

硅酸盐岩元素的准确测定是其地球化学分析研究的基础,其主量元素含量通常可以采用电感耦合等离子体发射光谱(ICP-AES)法测定,但其测定方法的系统性研究相对缺乏,尤其是样品前处理和基体干扰的有效消除两方面。前处理过程中,考察不同熔剂用量对硅酸盐岩样品的分解能力,发现当熔剂与样品比例达到6:1后,熔珠为纯色透明,经稀硝酸提取后溶液澄清,确定了硅酸盐岩前处理时熔剂与样品的最佳配比。测定过程中,通过考察基体匹配法和标准物质法两种基体干扰消除方法对测定结果的影响,发现当采用与岩性一致或者接近的标准物质绘制校准工作曲线时,基体干扰消除效果更好,更适用于测定硅酸盐岩10种主量元素含量。据此,建立了硅酸盐岩经偏硼酸锂熔融,稀硝酸振荡提取处理,以标准物质法绘制校准工作曲线,采用ICP-AES法同时测定SiO2、Fe2O3、Al2O3、CaO、K2O、MgO、Na2O、TiO2、P2O5、MnO 10种成分含量的方法。对岩石标准物质GBW07107进行分析测定,方法的相对标准偏差(RSD)为0.17%～0.75%,方法检出限为0.001%~0.016%,满足硅酸盐岩样品元素定量分析的要求,而且操作简单快速,环境污染小,适用于大批量样品分析。     

Petrochemical study of Al-Mizil plutonic rocks of Saudi Arabia

A petrochemical study of some rock samples has been carried out using different experimental techniques. The rock samples were collected from the Al-Mizil area, Saudi Arabia. Al-Mizil area consists of Precambrian metasediments which belong to the Halaban Formation. The plutonic rocks later intruded into the Halaban Formation. Major oxides and trace elements in these rocks are presented. The study indicates that the rocks are mainly of granitic composition. The petrochemical data suggest a magmatic origin for Al-Mizil granitic rocks.     

Boron concentration measurements by prompt gamma activation analysis: Application on miocene-quaternary volcanics of the Carpathian-Pannonian Region

Prompt gamma activation analysis is a highly powerful analytical method in geology, due to its applicability to determine the concentration of all major and few trace elements in whole rock samples. Furthermore, the boron concentration can be determined with proper accuracy without time consuming sample preparation. The reliability of this method was checked on geological standards and on other volcanic rocks, which were analyzed previously by XRF and TIMS for many major and trace element components and Sr-isotopes. Boron concentrations of volcanic rock samples from the East Carpathian Volcanic Field (Eastern-Central Europe) are reported here for the first time. The boron concentrations were measured for an improved definition of the petrogenezis of these rocks and to understand the fluid addition processes during subduction-related volcanism in this region.     

Provenance studies of obsidian artifacts: Trace elements analysis and data reduction

Iron and trace elements, such as rare-earth elements, scandium, rubidium, cesium, tantalum, thorium and uranium were determined by instrumental neutron activation analysis in geological samples of obsidian rocks from the Mediterranean Area and in obsidian artifacts found in some prehistorical human settlements in Italy. REE patterns and discriminant analysis allow a firm identification of the source material of artifacts, thus confirming and implementing fission track data of the same artifacts and rocks on the origin of the obsidian rock used to mould the artifacts.     

Volcanic Quartz Growth Zoning Identified by Cathodoluminescence and EPMA Studies

 Quartz is a common phenocryst in acidic volcanic rocks but rarely contributes to the understanding of the magmatic or eruptive processes due to its apparent chemical homogeneity. Cathodoluminescence studies indicate that volcanic quartz is strongly zoned with respect to the trace elements. The determination of this zoning can help to elucidate the crystallisation history of the magmatic rock. Polished thin sections from rhyolitic and dacitic volcanic rocks were examined by cathodoluminescence mounted on an optical microscope and analysed by electron probe microanalysis. X-ray mapping of the trace elements incorporated in the zoned quartz was also performed. The interpretation of the data obtained from these different analytical methods provides useful information on the chemical zoning of single crystals and therefore on the chemico-physical conditions of the melt from which the quartz crystallised. Quartz from dacitic rock shows a complex cathodoluminescence oscillatory zoning, consisting of large red-brown and blue bands concentric to a resorbed core. Quartz from rhyolite shows simpler cathodoluminescence zoning, consisting of dark to bright blue luminescent bands. The EMPA analyses and the X-ray maps combined with the cathodoluminescence images suggest a clear correlation between the concentrations of some trace element (mainly Al and Ti, acting as activators of luminescence) and the cathodoluminescence colours pattern zoning. The incorporation of these trace elements during the growth of the crystals is linked to small variations in the thermo-chemical properties of the magma such as temperature and chemical composition.     

Direct determination of traces of Ag, Cd, Pb, Bi, Cr, Mn, Co, Ni, Li, Be, Cu and Sb in environmental waters and geological materials by simultaneous multi-element graphite furnace atomic absorption spectrometry with Zeeman-effect background correction

A method was developed for direct determination of minor and trace amounts of Cr, Mn, Cu, Ni, Co, Li, Pb, Cd, Bi, Sb, Be and Ag in silicate rock, lake and stream sediments using a microwave oven dissolution method and a multi-element graphite furnace atomic absorption spectrometer equipped with a Zeeman-effect background correction device. The measurement technique was also suitable for direct determination of trace and ultra-trace amounts of these elements in drinking and seawater samples. A rock or sediment sample was brought into solution in a Teflon vessel by heating in a microwave oven with a mixture of hydrofluoric acid and aqua regia, followed by a further heating with a mixture of boric acid and ethylenediaminetetraacetic acid. The specified elements were directly determined in a group of four elements in one firing and eight elements in two firings from this solution or from a diluted solution using the optimum operating parameters developed in this work. The method, tested with 23 international reference rocks and sediments and seven international quality control and reference water samples, showed good to excellent agreement with the recommended values.     

Trace and major elements in rock samples from Itingussú River Basin, Coroa-Grande, Rio de Janeiro

Summary The goal of the present work was to determine the concentration of 23 elements by instrumental neutron activation analysis in rock samples from the vicinity of Itingussú River, in order to investigate the contribution of trace and major elements from the local lithology to the river basin. The Itingussú River Basin ends in a mangrove area not yet largely impacted by antropogenic activities. So far, there are no data for the concentration of trace elements in that region, even though these data are important to the understanding of the influence of the rocks on the composition of the mangrove sediments. The results showed some enrichment of Th and some light rare earths, probably because of the presence of the mineral allanite and other accessory minerals, as identified by petrographic analysis.     

Atomic absorption spectrometric determination of thirteen minor and trace metals in phosphate rock concentrates

Atomic absorption spectrometric methods are described for the determination of thirteen minor and trace elements in phosphate rock concentrates from Florida (U S.A.), Kola (U.S.S.R.) and Morocco. The techniques employed are atomization of solid or liquid samples in two types of graphite furnace, and conventional atomization in the flame or the cold-vapour cell.     

煤中痕量元素在循环流化床锅炉中的迁移行为与富集特性

对天津市某电厂循环流化床(CFB)锅炉燃用的原煤及燃烧产物底灰、飞灰、细飞灰(≤50 μm)进行痕量元素含量的测定,分析了Be、Zn、Hg、V、Cr、Mn、Co、Ni、Cu、As、Se、Cd、Pb 13种痕量元素在燃烧过程中的迁移行为,揭示了痕量元素在CFB锅炉中的分配、富集特性。结果表明,CFB锅炉中,较低的炉温对于痕量元素的迁移富集产生了较大的影响。由相对富集系数得知,Be、V、Co、Se在底灰中耗散,在飞灰中富集,Zn、Mn倾向于在底灰中富集,元素Cd、Pb、Ni、Cu挥发性较强,在底灰和飞灰中均是耗散。As受钙氧化物影响,挥发性表现并不明显。Hg在底灰和飞灰中相对富集系数均很低,表明Hg在整个燃烧过程中以气态形式排放;Hg、As、Se、V、Cr、Mn、Co、Ni、Cu、Zn、Pb均有向小颗粒物中富集的趋势。根据相对富集系数以及研究的13种元素在低温CFB锅炉中的迁移行为,将这些元素分为三类:A类(E_R<0.1),主要是以气态形式排放元素Hg;B类(0.1R≤0.85),较易挥发元素As、Be、Ni、Cu、Se、Cd、Pb、Co、V;C类(E_R>0.85),主要残留在固体产物中元素Zn、Mn、Cr。     

Determination of Nb, Ta, Zr and Hf in Micro-Phases at Low Concentrations by EPMA

 Depletion of high field strength elements (HFSE: Nb, Ta, Zr, Hf ) relative to other lithophile trace elements in arc magmas and variations of Nb/Ta and Zr/Hf ratios in mantle-derived rocks can be addressed through studies of minerals, which concentrate and fractionate these elements. The presence of rutile, a common accessory Ti-oxide phase in various mantle rocks, has often been invoked to explain the Nb and Ta depletion in arc lavas because it has the highest HFSE abundances among the known mantle minerals. In this study, we measure the concentrations of Nb, Ta, Zr and Hf (at > 200 ppm) in rutile of two metasomatized mantle lherzolites using a Cameca SX-100 electron microprobe and obtain Nb/Ta ratios with an accuracy of about ± 5%. Mass balance calculations indicate that ≤ 1−5% of Nb and Ta in the rocks reside in major minerals and that the balance is hosted by accessory Ti-oxides. The Nb/Ta ratios vary significantly in nearby rutile grains in both peridotites (17–33, average 23; 12–37, average 21). Therefore, individual rutile grains may not be representative of the total grain population. However, Nb/Ta ratios measured in the bulk rock lherzolites by solution ICP-MS (21 ± 0.3) are within the analytical error of the average Nb/Ta values calculated for 5–7 rutile grains in both samples. These results emphasise that a representative grain selection must be analysed in order to determine trace elements contents of bulk rocks from data on accessory phases.     

Trace element analysis by laser plasma mass spectrometry

Summary A double focusing mass spectrometer was equipped with a laser plasma ion source. This instrument has been used for multi-element analysis of solid materials. Laser plasma mass spectrometry (LMS) permits direct analysis of both conducting and non-conducting samples. The abundances of about 30 trace elements can be determined simultaneously in rock samples. A great advantage of LMS is that most elements are ionized with about the same efficiency, this means that only small corrections are necessary for quantitative analysis. Solutions which have been dried on a quartz disk can also be analyzed. This technique yields mass spectra which are free of interferences of molecules or cluster-ions.

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Spurenelementanalyse durch Laser-Plasma-Massenspektrometrie

     

Radiochemical neutron activation analysis of rare earth elements in peridotitic rocks

The understanding of the geochemistry of basalt petrogenesis and the nature of the upper mantle requires the examination of such rocks as peridotites which in many cases are thought to represent upper mantle material. The mineralogical composition of peridotitic rocks in such that they accommodate large proportions of such trace elements as the transition elements but very small amounts of the rare earths and hygromagmaphile elements. The last two groups are often able to provide a large amount of information leading to petrogenetic models. Owing to the extremely low concentrations of the REE in peridotitic rocks it is necessary to separate them from other elements which will interfere with their precise determination. We have used a radiochemical neutron activation analytical method which is adapted from various published methods. It involves a post-irradiation sample fusion, two separate ion-exchange chromatographic stages and finally a fluoride precipitation. The RNAA procedure is capable of providing very precise REE data for perioditic samples and we have used it for the analysis of such rocks from several geodynamic environments.     

The determination of indium and thallium in silicate rocks by a combined solvent extraction and spectrochemical technique

A technique has been developed for the determination of In and Tl at very low concentrations in silicate rocks. The iodo-complexes of these elements are extracted from the rock silicate into ethyl cther and the ethereal residues are analysed spectrochemically. The optimum working conditions were established by a study of the variation of percentage extraction as a function of hydrogen iodide normality ; the reproducibility of the spectrochemical procedure was investigated. In and Tl were determined in eight silicate rocks including standard granite G-I and standard diabase W-I. Good agreement was obtained with results of other workers for these two rocks and with the author's previous results. The evidence for a In/Mn coherence in silicate rocks is sufficiently strong to warrant further investigations.     

Heavy metal pollution from phosphate rock used for the production of fertilizer in Pakistan

Phosphate rock belongs mainly to sedimentary, slightly to igneous, and negligibly to metamorphic rocks. It is used for the production of phosphorous based fertilizers, acids, detergents and many products of common use. The rock is mainly composed of phosphorous and minutely of many other elements. The aim of this study was to determine the concentration of Cd, Cu, Cr, Ni, Pb, Zn (environmental pollutants i.e. toxic elements), and Co, K, Mg, Mn, Na (common elements) in phosphate rocks used for production of fertilizer in Pakistan. Rock samples of local origin were collected from the geological rock formations around the city of Abbottabad and those of foreign origin were obtained from the fertilizer factories and research institutes in Pakistan. Analysis of phosphate rock for all the elements of interest was carried out with Flame Atomic Absorption spectrometer (FAAS) except for sodium which was analyzed using Flame Photometer, while the concentration of potassium was determined using both the techniques. The results showed that heavy metal content was lower in Pakistani phosphate than that in imported rock and were below the safe limits with the exception of lead whose concentration was found to be higher in local phosphate deposits than that in imported rock samples. Phosphate rock is a source of heavy metal pollution of air, soil, water, food chain etc, therefore requires removal of heavy metals (HMs) from the rock prior to its use.     

Multi-element analysis by isotope dilution-spark source mass spectrometry (ID-SSMS)

Summary Isotope dilution-spark source mass spectrometry (ID-SSMS) has been applied for the simultaneous quantitative determination of about 35 trace elements in rock samples. A precision and an accuracy of better than 5% is obtained for most elements. Concentrations down to 0.01–0.1 ppm can be precisely determined for many trace elements.The application of ID-SSMS in geochemical and cosmochemical research is particularly interesting when concentrations of many elements are desired (e. g., for element correlations) and low detection limits are needed, or when only small amounts of samples are available.

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Multielement-Analyse mit Isotopenverdünnung-Funkenmassenspektrometrie (ID-SSMS)

     

Determination of trace elements in crude oils and organic materials extracted from oil-forming source rocks in China by INAA

A combination of Soxhlet extraction, column chromatography and INAA with GC and GC-MS was used in this work for the study of the abundance patterns of 36 trace elements and their correlation in nearly 100 samples of crude oil and organic materials extracted from oil-forming source rocks from 10 main Chinese oilfields. The low V/Ni ratios of 0.01 to 0.3 state the oil-forming continent environment. The geochemical significance hinted from other trace element abundances is also briefly discussed.     

TRACE ELEMENT GEOCHEMISTRY OF INARTICULATE BRACHIOPODS AND SEDIMENTARY ROCK ON THE CAMBRIAN-ORDOVICIAN BOUNDARY

That the contents and compositions of trace elements, especially REE in sedimentary rock and agustite originating from inarticulate brachiopods, conodont, etc. change in the vertical direction usually has a close relation with the stratigraphic boundary of important biologies. This paper systematically analyses REE and 16 trace elements such as U, Th, Sr, Ba, Co, Ni, Cr, V, Cu, Pb, Zn, Sc, Au, As in sedimentary rocks and the agustite on the standard stratified section of the Cambrian-Ordovician Boundary in Dayangcha, Huniiang, Jilin Province. Based on this, the authors investigate the REE distribution pattern and the law of the contents and compositions of trace elements changing, providing the geochemical evidence for building stratified sections of the Cambrian-Ordovician boundary and discussing sedimentary environments.     

Non-Destructive neutron activation analysis of zircons from different genetic types

Twelve zircon samples representing different genetic types from Australia, China, Egypt, Hungary, Korea and Nigeria were examined using the neutron activation techniques. The study of the trace elements encountered in zircons, especially Zr/Hf ratios, shed the light on the type of zircon minerals as well as the mother rock from which zircons wrre separated. Furthermore, the effect of the secondary processes on zircons and their host rocks were also studied.     

黔西南卡林型金矿床稀土元素地球化学特征

分析了黔西南地区板其、、丫他及戈塘等卡林型金矿床的(La/Yb)N、(La/Sm)N、∑REE及LREE/HREE等稀土元素的含量及参数特征.结果表明,该区金矿床相对富集LREE;该区戈塘金矿具有明显的MREE富集及正Eu异常的特点,表明成矿热液应该是一种还原性流体,来源于深部或至少经历过对富含斜长石源区的水-岩反应矿...     

Quantitative analysis of original and powdered rocks and mineral inclusions by laser ablation inductively coupled plasma mass spectrometry

Direct analysis of rocks by laser ablation inductively coupled plasma mass spectrometry is described. Both powdered standard rocks and the original rocks were analysed and the results agreed with each other in spite of the difference in the surface states. Microprobe analysis of biotite in granite JG1 was also done directly with a focused laser beam and the results obtained were very close to the solution values given by the conventional aqueous method using biotite separated from an original rock. For quantitative analysis, the measured signal intensity was normalized either by the ablated weight or the barium signal intensity. Forty-two major and minor elements (two of them being used as internal standards) in twelve standard rocks fromt the igneous rock series of the Geological Survey of Japan were determined successfully.