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本文提出了用ＩＣＰ－ＡＥＳ法直接同时测定高纯氧化钇中１４个稀土和１６个非稀土杂质元素的分析方法，对被测元素的 谱线、氧化钇基本及背景影响进行了研究，用标准加入法测出氧化钇基准中的微量杂质元素，消除了由于忽略基准中的杂质元素含量给高纯氧化钇分析测定带来的误差，同时对工作条件进行了优化。方法中各被测元素的检出限为0.003～1.31ug/g，能够满足生产过程中的质量控制及进出口商品检验 相似文献
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ZHONG Yi CHEN Zhong GONZALEZ Francisco Javier ZHENG Xufeng LI Gang LUO Yun MO Aibin XU Antao WANG Shuhong 《海洋学报(英文版)》2018,37(7):41-54
Ferromanganese nodules and crusts contain relatively high concentration of rare earth elements(REE) and yttrium(REY),with a growing interest in exploitation as an alternative to land-based REY resources.On the basis of comprehensive geochemical approach,the abundance and distribution of REY in the ferromanganese nodules from the South China Sea are analyzed.The results indicate that the REY contents in ferromanganese deposits show a clear geographic regularity.Total REY contents range from 69.1×10~(–6) to 2 919.4×10~(–6),with an average value of 1 459.5×10~(–6).Especially,the enrichment rate of Ce content is high,accounting for almost 60% of the total REY.This REE enrichment is controlled mainly by the sorption of ferromanganese oxides and clay minerals in the nodules and crusts.Moreover,the total REY are higher in ferromanganese deposits of hydrogenous origin than of diagenetic origin.Finally,Light REE(LREE) and heavy REE(HREE) oxides of the ferromanganese deposits in the study area can be classified into four grades: non-enriched type,weakly enriched type,enriched type,and extremely enriched type.According to the classification criteria of rare earth resources,the Xisha and Zhongsha platform-central deep basin areas show a great potential for these rare earth metals. 相似文献
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Monazite petrogenesis in the Nelson contact aureole is the result of allanite breakdown close to, but downgrade and therefore independent of, major phase isograds involving cordierite, andalusite and staurolite. The development of garnet downgrade of the staurolite and andalusite isograds does not appear to affect the onset of the allanite-to-monazite reaction but does affect the textural development of monazite. In lower pressure, garnet-absent rocks, allanite breakdown results in localized monazite growth as pseudomorphous clusters. In higher pressure, garnet-bearing rocks, allanite breakdown produces randomly distributed, lone grains of monazite with no textural relationship to the original reaction site. Fluids liberated from hydrous phases (chlorite, muscovite) during garnet formation may have acted as a flux to distribute light rare earth elements more widely within the rock upon allanite breakdown, preventing the localized formation of monazite pseudomorphs. Despite these textural differences, both types of monazite have very similar chemistry and an indistinguishable age by electron microprobe chemical dating (157 ± 6.4 Ma). This age range is within error of isotopic ages determined by others for the Nelson Batholith. Garnet from the garnet, staurolite and andalusite zones shows euhedral Y zoning typified by a high-Y core, low-Y collar and moderate-Y annulus, the latter ascribed to allanite breakdown during garnet growth in the garnet zone. The cause of the transition from high-Y core to low-Y collar, traditionally interpreted to be due to xenotime consumption, is unclear because of the ubiquitous presence of xenotime. Accessory phase geothermometry involving monazite, xenotime and garnet returns inconsistent results, suggesting calibration problems or a lack of equilibration between phases. 相似文献
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Highly variable distributions of yttrium and rare earth elements (Y+REEs) are documented in pelitic garnet from the Picuris Mountains, New Mexico, and from Passo del Sole, Switzerland, and in mafic garnet from the Franciscan Complex, California. The wide variety of these Y+REE zoning patterns, and those described previously in other occurrences, imply diverse origins linked to differing degrees of mobility of these elements through the intergranular medium during garnet growth. In the Picuris Mountains, large, early‐nucleating crystals have radial profiles of Y+REE dominated by central peaks and annular maxima, in patterns that vary systematically with atomic number. Superimposed on these features are narrow spikes in HREEs and MREEs, located progressively rimward with decreasing atomic number. In contrast, profiles in small, late‐nucleating crystals contain only broad central maxima for all Y+REEs. In garnet from Passo del Sole, Y+REE zoning varies radically from sample to sample: in some rocks, crystals of all sizes display only central peaks for all Y+REEs; in others, profiles exhibit irregular fluctuations in Y+REE contents that match up with small‐scale patchy zoning in Y and Ca X‐ray maps. In the Franciscan Complex, Y+REE in garnet cores fluctuate unsystematically, but mantles and rims display concentric oscillatory zoning for both major elements and Y+REEs. Our interpretation of the complexity of Y+REE distributions in metamorphic garnet centres on the concept that these distributions vary primarily in response to the length scales over which these elements can equilibrate during garnet growth. Very short length scales of equilibration, due to low intergranular mobility, produce overprint zoning characterized by small‐scale irregularities. Higher but still restricted mobility yields diffusion‐controlled uptake, characterized by patterns of central peaks and annular maxima that vary with atomic number and are strongly influenced by T–t paths during garnet growth. Still greater mobility permits progressively greater, potentially rock‐wide, equilibration with major‐ and accessory‐phase assemblages, leading to mineralogical controls: an unchanging mineral assemblage during garnet growth produces bell‐shaped profiles resembling those produced by Rayleigh fractionation, whereas changes in major‐ and/or accessory‐phase assemblages produce profiles with distinct annuli and sharp discontinuities in concentration. The very high mobility associated with influxes of Y+REE‐bearing fluids can cause these element distributions to be dominated by factors external to the rock, yielding profiles characterized by abrupt shifts or oscillations that are not correlated to changes in mineral assemblages. 相似文献
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This study examines the rare earth elements and yttrium (REY) concentrations of twenty-five samples from the reef outcrop exposed along the Lianglitage Mountain in the Ordovician, Tarim Basin in China. The concentration analysis provides constraints on the paleoenvironment during reef deposition. Based on the detailed sedimentology and petrographic work, we divide the reef facies into four sub-facies: the base facies, reef-core facies, reef-flank facies, and sealing facies. The geochemical data (such as major and trace elements, carbon and oxygen isotopes, and REYs) are further used to study the coeval seawater characteristics as well as potential diagenesis overprints. The result indicated that the diagenesis has little effect on the REY patterns of the reefal limestones. The REY concentrations of the reefal limestones are overall low (ranging from 3.69 to 19.60 ppm, arithmetic mean=10.22 ppm, SD=5.4). The PAAS-normalized REY patterns are consistently flat compared to the typical well-oxidized, shallow marine water patterns. However, the light REE (LREE) depletions, positive La anomalies, negative Ce anomalies and positive Y anomalies, suggest that these reefal limestones are likely an indicative of contemporaneous seawater REY signals. The seawater-like Y/Ho ratios (average at 37.51) further support that REY signals in these limestones are likely a reflection of seawater with little diagenetic modifications. The low Y/Ho ratios presented only in the reef-flank facies and sealing facies are likely a suggestion of detrital contamination. Hence, this study confirms that REY patterns of the limestones at the base facies and reef-core facies can record ancient seawater information, and reefs can be used as a potential geochemical proxy for paleoenvironment studies throughout the Earth’s history. 相似文献
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The relative timing of two discrete pulses of metamorphic fluid flow is constrained based on chemical zoning in several garnet crystals from Kvaløya, Troms, northern Norway. The garnet crystals measured 1–2 cm in diameter and were contained within c. 1.6 Ga, staurolite grade metasediments. Major element zoning indicates that garnet grew under normal prograde conditions in the garnet and/or staurolite zones. Timing constraints are based on comparisons between major and trace element chemical zoning, oxygen isotope (δ18O) zoning and deformational (inclusion trail) zoning in one of the garnet. We interpret at least two pulses of metamorphic fluid flow. The first pulse occurred during the syn‐tectonic growth interval. The δ18O zoning was reversed relative to ‘normal’ prograde zoning and the δ18O maximum was located within the syn‐tectonic growth zone, displaced 3–4 mm from the garnet core. The fluid might have been sourced in neighbouring calcareous pelites and may also have caused formation of an Y ring. The second (and subsequent) pulse(s) occurred during/after the post‐tectonic growth interval. δ18O was locally increased at the garnet rim, particularly where the rim was sheared. The incomplete rim was also enriched in calcium. Transport of oxygen and calcium by metamorphic fluids is well documented. Transport of Y is both problematic and poorly understood, but might have been facilitated by complexing with F and/or CO2. 相似文献
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高分辨电感耦合等离子体质谱法测定地球化学样品中钪钇和稀土元素 总被引：4，自引：2，他引：2
建立了高分辨电感耦合等离子体质谱法(HR-ICP-MS)测定地球化学样品中钪、钇、镧、铈、镨、钕、钐、铕、钆、铽、镝、钬、铒、铥、镱和镥的分析方法。样品经氢氟酸-硝酸-硫酸-王水消解,试液直接用HR-ICP-MS测定钪、钇和14种稀土元素。用高分辨模式有效地避免了多原子离子及难熔氧化物离子对待测元素测定的干扰,为钪、钇和14种稀土元素选择了最佳的测定同位素和合适的分辨率;用地球化学标准物质制备的溶液优化仪器工作参数,确定了最佳的仪器测定条件。方法检出限(6σ)为0.003～0.013μg/g(稀释因子为1000),相对标准偏差(RSD,n=12)小于6%。方法经国家一级地球化学标准物质验证,测定值与标准值吻合。 相似文献
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电感耦合等离子体原子发射光谱法测定高纯氧化钇中稀土杂质元素 总被引：1，自引：0，他引：1
拟定了电感耦合等离子体原子发射光谱法测定高纯氧化钇中１４个稀土杂质的方法,选择了仪器的最佳工作条件,考察了基体效应的影响,在选定条件下,１４个稀土元素的检出限为（０．０６～１．１０）μｇ／ｇ,相对标准偏差（ｎ≥１０）为０．９８％～９．３％,加标回收率为９３％～１１４％。方法不经预分离富集处理,在大量基体中成功地测定了含量在μｇ／ｇ级的稀土杂质元素。 相似文献