11 |
A implantação de rotina, e seu refinamento, para a determinação de elementos Terras Raras em materiais geológicos por ICP-OES e ICP-MS. Aplicação ao caso dos granitóides de Piedade-Ibiúna (SP) e Cunhaporanga (PR) / The routine development to determination of Rare Earth elements in geological materials by ICP-OES and ICP-MS. Aplictaion in granitoid rocks from Piedade-Ibiúna (SP) and Cunhaporanga (PR) complexesMargareth Sugano Navarro 15 June 2004 (has links)
No presente trabalho são descritas as etapas de desenvolvimento e implantação das rotinas analíticas utilizando ICP-OES e ICP-MS para a determinação de elementos terras raras em materiais geológicos. A implantação inclui determinações comparativas de vários granitóides dos maciços ou complexos Ibiúna-Piedade, SP, e Cunhaporanga, PR, já previamente analisados por meio de ICP-MS e INAA (Universidade Kansas, em Lawrence, USA). Através de uma pequena modificação no método inicial, os limites de detecção para a análise dos ETR por ICP-OES foram melhorados para concentrações próximas à 10 vezes o condrito. Porém para a análise de ETR em materiais geológicos com valores inferiores a estes é necessária a utilização de uma técnica mais sensível como o ICP-MS. A técnica ICP-MS não é livre de problemas sendo necessárias correções de interferências moleculares e drift instrumental para a obtenção de resultados com precisão e exatidão adequados. Realizou-se a etapa de validação do método utilizando materiais de referência internacionais geológicos. A análise estatística dos resultados obtidos utilizando três métodos de abertura de amostra (ataque ácido em forno de microondas, em bombas tipo Parr e fusão alcalina) mostrou a possibilidade de utilização do ataque ácido em forno de microondas e da fusão alcalina com posterior separação cromatográfica como alternativas eficientes para a determinação de ETR apesar da baixa eficiência nas recuperações dos elementos Zr e Hf em rochas ácidas e gnáissicas equivalentes. / The steps for the development of the analytical routines leading to the determination of the rare earth elements (REE) with the use of ICP-AES and ICP-MS techniques are discussed in this contribution. The set-up of these routines was also evaluated with determinations of REE in several granitoid rocks from the Piedade-Ibiuna (SP) and Cunhaporanga (PR) complexes, and the results compared with those obtained in other laboratories (University of Kansas, Lawrence) with ICP-MS and INAA. The work previously performed for the adaptation of REE determination with ICPAES was reviewed, allowing analyses to be realized with better results for concentrations close to 10 times the chondrite value. At lower concentrations, REE analysis have to be performed with ICP-MS. The ICP-MS technique shows much better accuracy and precision than ICPAES, but presents problems of its own. Instrumental drift corrections, as well as corrections due to molecular interferences, are mandatory. Evaluation of the successfully adapted routines was realized analyzing international reference materials several times and applying statistical tests. A comparison of results with three dissolution techniques (acid attack in microwave oven, use of Parr type bombs, and alkaline fusion with borates) showed that both acid attack and alkaline fusion with later chromatographic separation are rather efficient alternatives for the determination of REE, although Zr and Hf are not fully recovered in many acid igneous and equivalent gneissic rocks.
|
12 |
Viabilidade da medida de elementos-traço em soro sanguíneo para diagnóstico de melanoma / Trace elements measurement in blood sérum for the diagnosis of melanoma a viability studySuene Bernardes dos Santos 01 October 2012 (has links)
A medida e o controle de elementos químicos, majoritários ou traço, em tecidos e fluídos biológicos, vem sendo utilizada há muito tempo para diagnósticos médicos, em avaliações de saúde, estado nutricional e para prevenção e acompanhamento de doenças. Em muitos casos tal relação já foi solidamente estabelecida, mas no estudo de neoplasias, ainda se busca relação entre teores químicos elementares e vários tipos (ou estágios) de câncer. Nesse tipo de estudo utilizam-se métodos espectroscópicos multi-elementares de altíssima sensibilidade ainda não disponíveis rotineiramente em laboratórios clínicos. Neste trabalho, buscaram-se alterações na concentração de elementos químicos majoritários e traço em soro sanguíneo de pacientes com melanoma, por meio de análises pelos métodos PIXE e HR-ICPMS como auxiliar de diagnóstico desta neoplasia, uma vez que sua detecção em estágios iniciais aumenta a probabilidade de recuperação. A técnica PIXE (Proton Induced X-ray Emission) de análise multi-elementar baseia-se na detecção de raios X característicos, enquanto o HR-ICPMS (High Resolution Inductively Coupled Plasma Mass Spectrometry) é um espectrômetro de massa de alta resolução. As amostras de sangue de 30 pacientes e 116 doadores sadios foram coletadas no Hospital São Paulo (protocolos CEP 1036/08 UNIFESP) em tubos de vidro sem aditivos, sendo o soro separado por meio de centrifugação a 4500 rpm durante 15 minutos. Foram identificados e quantificados um total de 10 elementos: 4 por HR-ICPMS (Mg, Se, Cu e Zn) e 8 por PIXE (P, S, Cl, K, Ca, Br, Cu e Zn). Os métodos analíticos foram aferidos com os materiais de referência QMEQAS06S-06, QMEQAS08S-06 e NIST 1577b. A precisão analítica variou de 3 % a 9 % para ambas as técnicas. As informações clínicas relevantes dos pacientes foram incluídas na análise (tipo histológico do tumor; nível de melanoma; escala de Breslow em profundidade; número de linfonodos; presença ou ausência de mitose e/ou ulceração). A avaliação do grupo controle mostrou diferentes concentrações de P e Mg para indivíduos com idade acima ou abaixo de 40 anos. Os teores de P, S, Ca, Cu e Zn em indivíduos saudáveis apresentaram diferenças com o gênero, evidenciando a necessidade de inserir estas variáveis na análise caso-controle. As concentrações de K, S, Ca e Se apresentaram diferença entre os grupos controle e melanoma, quando consideradas as variáveis clínicas dos pacientes (p<0,05). A necessidade de estratificação por idade, gênero e estágio da neoplasia, reduziu criticamente o já limitado espaço amostral, comprometendo a interpretação das pequenas diferenças nas concentrações elementares encontradas. Os resultados encontrados para a população sadia concordaram com os valores publicados na literatura e colaboraram para o fortalecimento do banco de dados de concentrações elementares em soro da população brasileira. / Recording chemical elements, either as major or trace quantities, in tissues and biological fluids is regularly being used for medical diagnosis, health assessments, nutritional status, and for the monitoring and prevention of diseases. In many cases, such relationship is firmly established, but for cancer, there is still a search for a relationship between chemical elements and various types (or stages) of cancer. In this kind of study, highly sensitive multielemental spectroscopic methods are used which are not yet routinely available in clinical laboratories. In this study, changes in the concentration of chemical elements in serum of melanoma patients were sought by means of PIXE and HR-ICPMS analysis as an aid to early diagnosis, and to help increasing the likelihood of pacients recovery. The multi-elemental PIXE method (Proton Induced X-ray Emission) relies on the detection of characteristic X-rays of the sample, while the HR-ICPMS (High Resolution Inductively Coupled Plasma Mass Spectrometry) is a high resolution mass spectrometer. Blood samples from 30 patients and 116 healthy donors were collected at the Hospital (protocols CEP 1036/08 UNIFESP) in glass tubes without additives, and the serum separated after centrifugation for 15 minutes at 4500 rpm. A total of 10 elements were measured: 4 by HR-ICPMS (Mg, Se, Cu and Zn), 8 by PIXE (P, S, Cl, K, Ca, Br, Cu and Zn). The analytical methods were assessed analyzing reference materials QMEQAS06S-06, QMEQAS08S-06 and NIST 1577b. The analytical precision ranged from 3 % to 9 %. Relevant clinical information of patients has also been included in the statistical analysis (histological type of tumor, level of melanoma, Breslow depth scale, number of lymph nodes, presence or absence of mitosis and/or ulceration). The evaluation of the control group showed different concentrations of P and Mg for individuals aged above and below 40 years. The P, S, Ca, Cu and Zn in healthy individuals differed according to the gender, highlighting the need of inserting the variables age and gender in the case-control analysis. The concentrations of K, S, Ca and Se showed differences between the control group and the melanoma, when considering the clinical variables of the patients (p <0.05). The need for stratification by age, gender and stage of cancer, critically reduced the already limited number of samples, compromising the interpretation of the small differences in elemental concentrations found. The results for the healthy population agreed with the values reported in the literature and contributed to strengthen the database of elemental concentrations in serum of the Brazilian population.
|
13 |
Metody speciační analýzy sloučenin arsenu. / Methods for Elemental Speciation of Arsenic Compounds.Navrátilová, Jana January 2011 (has links)
Speciační analýza arsenu v různých matricích s využitím HPLC/ICPMS byla předmětem této práce. Toxicita arsenu závisí na oxidačním stavu a formě, ve které je přítomen. Znalost zastoupení specií arsenu je nutná k hodnocení toxicity a biodostupnosti. Obecně, anorganické specie jsou více toxické než organické. V práci byla studována degradace arsenocukrů v mořských řasách za simulovaných přirodních podmínek. Původní arsenocukry byly transformovány na arseničnan a kyselinu dimethylarseničnou. Arsen vstupuje do rostlin z půdy a vody a následně může vstoupit do potravního řetězce. S ohledem na tuto skutečnost byla speciační analýza provedena u vybraných vzorcích rýže, zakoupených v české obchodní síti. Stanovený celkový obsah arsenu se pohyboval v rozmezí 36.06 µg/kg - 218.11 µg/kg a hlavními speciemi byla kyselina dimethylarseničná a anorganický arsen (54-78%). Mořské ryby a tuky obsahují významnou část arsenu ve formě zvané arsenolipidy. Část práce byla zaměřena na analýzu arsenolipidů u máslové ryby (Lepidocybium flavobrunnrum) s celkovým obsahem arsenu 1.8 mg/kg a 22% celkového arsenu bylo vyextrahováno pomocí hexanu, což potvrzuje lipofilni charakter těchto sloučenin. Hlavní specií stanovenou ve vodném extraktu byl arsenobetain, představující 89%.
|
14 |
Contrefaçon du vin : développement de méthodes d'analyse multifactorielles rapides et non destructives pour l'authentification des bouteilles par des techniques spectrochimiques couplées à un rayonnement laser / Wine counterfeiting : development of fast, non-destructive and multifactorial laser-based spectrochemical methods for authentification of bottled wine.Grijalba Marijuan, Nagore 08 November 2017 (has links)
La connaissance du raisin et du vin est aussi vieille que l’histoire culturelle de l’humanité. Il est bien connu depuis l'ancienne civilisation l'influence du «terroir» sur le vin, c'est-à-dire un espace géographique délimité où une communauté humaine construit au cours de l’histoire un savoir collectif de production qui confère une typicité et engendrent une réputation pour un produit originaire de cet espace géographique. Les grands vins, tout comme les vins de moindre renommée, représentent une cible privilégiée des faussaires. La contrefaçon s’intensifie et se développe en grande partie en Chine. Selon la comission du vin et spiritueux du Comité National des Conseillers du Commerce Extérieur de la France, il existe au moins une bouteille de vin forgé pour chaque bouteille de vin français original. Bien que la Chine ne soit pas le seul fournisseur de vins contrefaits, la croissance rapide du marché du vin dans ce pays et l'absence de lois protégeant la propriété intellectuelle ont déclenché le marché noir. On estime que 20% des vins consommés dans le monde sont contrefaits. Selon l’Office de l’Union Européenne pour la propriété intellectuelle, l’industrie des vins et spiritueux européenne perd environ 1,3 milliard d’euros chaque année du fait de la contrefaçon sur le marché de l’UE, ce que correspond à 3,3% de ventes de ces secteurs, ce qui se traduisent en une perte directe d’environ 4800 emplois. La contrefaçon des vins peut revêtir plusieurs formes et les mesures de lutte contre la contrefaçon en vigueur ont montré leur manque d’efficacité. Ce sont des techniques invasives qui sont utilisés lors de la vérification des vins. Elles sont basées principalement sur une analyse du contenu et nécessitent donc l’ouverture de la bouteille, ce qui est dommageable lorsqu’il s’agit de vins de grande valeur. Le travail présenté ici, présente un nouvel outil de diagnostic non ambigu basé sur l'analyse ultra-trace des matériaux constituant l’emballage (verre, papier et encres, capsule) par ablation laser femtoseconde ICPMS. Cette technique non invasive est rapide (5 minutes environ), permet de détecter des traces élémentaires inférieures au ng/g et n’a pas d’équivalent en terme de performance à ce jour. Dans une première étape, nous avons designée et développé une nouvelle cellule d’ablation qui permet de réaliser l’analyse multiélémentaire direct en n’induisant aucune dégradation visible sur la bouteille. Dans une deuxième étape, la nouvelle cellule d’ablation a été apliquée a l’analyse direct de l’emballage. Pour l’analyse du papier et des encres, en raison du manque de matériaux de référence certifiés, représente un véritable challenge analytique. Nous avons mis au point une approche quantitative en développant nos propres standards par impression jet d’encre de papier à partir de solutions dopées. Finalement, un nouvel outil de diagnostic non ambigu basé sur l’espectroscopie Raman et Infrarouge a été développée pour l’analyse moleculaire qualitatif et direct du papier et des encres afin de compléter les résultats obtenus avec le fsLA-ICPMS. L’instrumentation et ces méthodes de caractérisation des emballages ont été appliquées avec succès à l’analyse d’un grand nombre de bouteilles (n>200) d’origine contrôlée et de bouteilles originaires d’autres pays. Les traitements statistiques des données basés sur une analyse multivariée (PCA, PLS, classification hiérarchique) montrent clairement la distinction entre les bouteilles d’origines et les bouteilles contrefaites en isolant et hiérarchisant les éléments traces à l’origine de cette discrimination. Il a par ailleurs été possible de différencier la signature chimique des bouteilles selon leur origine géographique et le millésime. / The knowledge of grape and wine is as old as the cultural history of humankind. It is well known since the ancient civilizations the influence of the "terroir" on wine, which is a limited geographical space where a human community constructs a collective knowledge of production, which gives wine grapes their distinctive character and generate a reputation for a product originating from this geographical area. The great wines are a prime target for counterfeiters because of their brand value, mostly originating from the Asian market. According to the National Committee of Foreign Trade Advisers of France (Comité National des Conseillers du Commerce Extérieur de la France, CNCCEF) the wine fraud is not just a matter of a few bottles but also includes an entire clandestine industry. According to the Wine and Spirits Commission of the CNCCEF, there is at least one bottle of forged wine for each bottle of original French wine in China. Although China is not the only supplier of counterfeited wines, the rapid growth of the wine market in this country and the absence of laws protecting intellectual property have triggered the counterfeit market. It is estimated that 20% of the wines consumed in the world are counterfeit. In fact, according to the European Union Intellectual Property Office, it is estimated that the legitimate industries losses approximately €1.3 billion of revenue annually due to the presence of counterfeit spirits (€740 million) and wine (€530 million) in the EU market, 3.3% of the sector’s sales, which results in a direct loss of about 4,800 jobs. Wine fraud may be categorized in several forms and anti-counterfeiting measures have shown lack of effectiveness. Unfortunately, invasive techniques are used for wine verification purposes, which are mainly based on liquid sampling, requiring opening the bottle that can be fateful when it comes to great value wines. This work presents a new unambiguous diagnostic tool based on the ultra-trace analysis of the wine packaging (glass, paper and inks, capsule) by femtosecond laser ablation coupled to ICPMS. This is a fast (about 5 minutes) and non-invasive technique, which allows detecting trace elements below ng/g and has no equivalent in terms of performance to date. In a first step, we have designed and developed a new ablation cell that allows direct and multi-elemental analysis of the packaging without causing any visible degradation on the bottle. In a second step, the new ablation cell has been applied to the direct analysis of the packaging components. For the analysis of paper and inks, as the lack of certified reference materials represents a real analytical challenge, we have developed a quantitative approach by developing our own standards by printing spiked solution with an inkjet printer. Finally, in order to complement the results obtained with fsLA-ICPMS, a new unambiguous diagnostic tool based on Raman spectroscopy and Infrared spectroscopy has been developed for the qualitative and direct molecular analysis of paper and inks. The instrumentation and packaging characterization methods have been applied to the analysis of a large number of bottles (n> 200) of controlled origin and bottles originating from other countries. The statistical processing of data based on multivariate analysis (PCA, PLS, hierarchical classification) clearly shows the distinction between authentic and counterfeited bottles by isolating and prioritizing the trace elements responsible for this discrimination. It was also possible to distinguish the chemical signature of the bottles according to their geographical origin and the vintage.
|
15 |
Stanovení vybraných kovů v ovocných kompotech / Determination of selected metals in fruit compotesHauerlandová, Petra January 2012 (has links)
This diploma thesis deals with the determination of some metals in fruit compotes packed in cans. There is described the production of fruit compotes and metal packaging legislation relating to the studied issues, the possibility of contamination of food packaging components, packaging corrosion, metal migration from packaging and techniques used for the analysis of metals in the food industry. Concentrations of metals in 14 different fruit compotes from a commercial network in the Czech Republic were determined by ICP-MS technique in the experimental part. Concentrations of metals were detected only in the juice of stewed fruit, because the juice is in direct contact with the surface of packaging, and metals are transferred first into it. The measured values were compared with the maximum permissible levels of metals in fruit compote determined by European legislation. In some cases there were found higher concentrations of tin, but other metals did not exceed the allowable amounts. Concentrations of metals in the compote varied depending on the kind of compote, which could be due to a different chemical composition of compotes depending on the origin of food and process of the fruit production, or a different cans coating material.
|
16 |
In-situ quantitative analysis of trace elements in metal grains from H,L and LL ordinary chondrites using femtosecond laser ablation-ICP-mass spectrometry / フェムト秒レーザーアブレーションICP質量分析法によるH, L, LL普通コンドライト中金属粒子の局所微量元素分析Yokoyama, Takaomi 23 July 2014 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第18495号 / 理博第4010号 / 新制||理||1578(附属図書館) / 31381 / 京都大学大学院理学研究科地球惑星科学専攻 / (主査)教授 平田 岳史, 准教授 伊藤 正一, 教授 土`山 明 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM
|
17 |
A LA-ICPMS Sr Isotope and Trace Element Study of Plagioclase and Clinopyroxene of the Higganum Dike, Connecticut: Determining the Magma Source of the Central Atlantic Magmatic ProvinceHarper, Caprise Steadman 17 November 2009 (has links) (PDF)
The Higganum dike of Connecticut is one of the earliest basaltic dikes of the Central Atlantic Magmatic province and is geochemically representative of the widespread low-Ti basaltic lavas (~1 wt % TiO2) that make up the majority of the province in North America. Liquid compositions calculated from Cr-rich clinopyroxene cores from the Higganum dike are significantly more primitive than the bulk rock with average Mg# s of 0.63 compared to the Higganum dike which has Mg #'s ~ 0.55. However, the negative Nb and positive Pb anomalies that are seen in trace element patterns of the low-Ti group are also found in the liquids calculated from the Cr-rich clinopyroxene cores. Ca-rich plagioclase cores that probably come up from depth with the Cr-rich clinopyroxenes were found to be more radiogenic than bulk Earth with 87Sr/86Sri ratios ranging from 0.7057 to 0.7064. We conclude that this enriched isotopic signature and the trace element signatures of primitive liquids calculated from clinopyroxene are inherited from the source. This source is identified as a subduction-enriched metasomatized lithospheric mantle. High-Ti magmas (~2-5 wt % TiO2) that are limited to a small geographic area of the Central Atlantic Magmatic Province were found to be unrelated to the low-Ti magmas. These two groups probably originated from different degrees of partial melting of different sources and follow distinctive differentiation paths.
|
18 |
Developing Innovative Metallomics Approaches to Characterize Trace BiometalsChan, Qilin 19 April 2011 (has links)
No description available.
|
19 |
Analysis of Protein:RNA Cross-links by Inductively Coupled Plasma Mass Spectrometry and Tandem Mass SpectrometryCatron, Brittany Lyn 27 September 2012 (has links)
No description available.
|
20 |
Análises por LA-ICPMS em zircões de rochas graníticas da Faixa Ribeira no Estado de São Paulo - SE do Brasil: implicações genéticas e geocronológicas / Analytical determinations by LA-ICPMS in zircons from granitic rocks of the Ribeira Belt in the state of São Paulo - SE of Brazil: Genetic and geochronological implicationsAndrade, Sandra 10 June 2016 (has links)
Os granitoides da Faixa Ribeira, sudeste do Estado de São Paulo, aparecem como complexas intrusões, aflorando em todos os \"domínios\" geológico-estruturais do embasamento paulista. Neste trabalho, foram avaliados os batólitos Cantareira, São Roque e Itaqui, os plútons Taipas e Tico-Tico, e os turmalina-granitos de Perus, no Domínio São Roque; o batólito Itu e a intrusão Terra Nova (Domínio Jundiaí); o Granito Itaquera (Domínio Embu); o granito da Ilha Anchieta e o charnockito Ubatuba (Domínio Costeiro). Este estudo observa os padrões de evoluções petrogenéticas nos granitoides, com utilização de determinações geoquímicas e isotópicas em rochas e em zircão. A espectrometria de massa (por quadrupolo) associada à ablação a laser (LAQ-ICPMS) foi aplicada para determinar elementos traço em zircão. Dados analíticos de materiais de referência (zircão 91500 e zircão GJ-1) são apresentados no capítulo sobre metodologias. Os dados lito-geoquímicos indicam que as amostras pertencem a linhagens metaluminosas a peraluminosas com elevados teores de K. Granitos metaluminosos (Cantareira, Itaqui, etc.) mostram elevados teores de Sr e da razão Sr/Y, sem anomalia de Eu, em magmas provavelmente formados em profundidade, com granada estável. Os demais granitos mostram-se compatíveis com origem a pressões menores, com plagioclásio estável (anomalia negativa de Eu, baixos teores de Sr). Os zircões, em geral, mostram teores elevados de ETR, Th e U. Os diagramas normalizados de ETR mostram anomalias positivas de Ce, geradas em ambiente oxidante. Os zircões das amostras Tico-Tico, Itu, Terra Nova, Ilha Anchieta, Itaquera, Perus e charnockito Ubatuba apresentam anomalias negativas de Eu, provavelmente determinada pela co-cristalização com plagioclásio. Os elevados teores de ETR e Y nos zircões indicam a atuação de reações acopladas tipo xenotima, com substituição de \'Si POT.4+\' por \'P POT.5+\' e de \'Zr POT.4+\' por\' ETR POT.3+\', \'Y POT.3+\'. O geotermômetro Ti-em-zircão (\'T ANTPOT.zir.\') rendeu, em geral, temperaturas de cristalização equivalentes às temperaturas de saturação de zircão e apatitas em magmas. Zircões com núcleos reabsorvidos e com reflexão escura em CL apresentaram Tzir não realistas, acima de 1000°C, devidas a incorporação exagerada de Ti junto com ETR e P, por influencia de fluidos hidrotermais, que transportam também outros elementos HFS (Nb, Ta, Mo). Os resultados de idades U-Pb em zircão destes granitóides levam a valores entre 580 a 603 Ma, 30 Ma mais jovens que os da literatura. As razões Lu-Hf mostram similaridade entre os protólitos dos granitos São Roque e Itaquera, com uma possível fonte Paleoproterozóica (~2.9 Ga) e com \'épsilon\'\'Hf de -22.8, de elevada residência crustal; as idades TDM (Sm-Nd) estão entre 2.2 e 2.5 Ga, possivelmente representando uma fonte crustal associada a Paleoplaca São Francisco. Para os demais granitoides (Domínios São Roque e Jundiaí) é necessária uma fonte mais radiogênica para os valores de \'épsilon\'Hf (-18 a -11) e \'épsilon\'\'Nd (-12 a -9). As idades TDM, e as mais antigas U-Pb obtidas em alguns núcleos herdados de zircão, indicam fonte constituída por crosta continental juvenil acrescida durante evento vulcânico (por rifteamento) em 1.75 Ga, dentro da placa tectônica, devido a abertura continental, ou mesmo durante eventos ocorridos cerca de 2.1 Ga dentro de Cráton São Francisco. / The granitoids of the Ribeira Belt, southeastern São Paulo state, southeastern Brazil, are found as complex intrusions spread out uniformly in all structural-geologic \"domains\" of the São Paulo basement area. In our work, samples were studied from the Cantareira, São Roque and Itaqui batholiths, the Taipas and Tico-Tico plutons and the Perus tourmaline granites (São Roque Domain), the Itu batholith and the Terra Nova intrusion (Jundiai Domain), the Itaquera granite (Embu Domain), the Ilha Anchieta granite and the Ubatuba charnockite (Costal Domain). This study aims to unravel the pattern of petrogenetic evolution in the granitoids, with the help of geochemical determinations in rocks and zircon crystals. Quadrupole mass spectrometry with laser ablation (LA-Q-ICPMS) was applied to determine trace elements contained in zircons. Analytical data for reference materials (zircons 911500 and GJ-1) are presented in the chapter on Methodology. The lithogeochemical data show that the granites represent meta-aluminous to peraluminous lineages, with significant potash contents. Meta-aluminous samples (Cantareira, Itaqui, etc.) are high in Sr, also with high Sr/Y ratios and no Eu anomalies, representing magmas probably formed at considerable depth, implying garnet stability. The other granites were formed from magmas at lower pressures (stable plagioclase; negative Eu anomaly; low Sr contents). Zircons from these granites contain high REE, U and Th abundances. Normalized REE diagrams present positive Ce anomalies, generated in oxidizing environments. Zircons from Tico-Tico, Itu, Terra Nova, Ilha Anchieta, Itaquera, Perus and the Ubatuba charnockite are characterized by negative Eu anomalies, probably controlled by co-crystallization with plagioclase. The high REE and Y contents in zircons are explained by coupled xenotimetype reactions, with substitution of \'Si POT.4+\' by \'P POT.5+\' and \'Zr POT.4+\' by \'REE POT.3+\', \'Y POT.3+\'. The Ti-in-zircon geothermometer (\'T ANTPOT.zir\') yields, in general, temperatures comparable to the ones obtained with the saturation temperatures of zircons and apatites in magmas. Zircons showing reabsorbed cores and dark reflection areas under CL yield unrealistic temperatures above 1000°C, explained by anomalous uptake of Ti, together with high REE and P contents, on account of hydrothermal fluid activity, also responsible for transporting other HFSE (Ta, Nb, Mo). Dating results with the U-Pb technique in zircons show values between 580 and 603 Ma, 30 Ma younger than results previously published. Lu-Hf ratios suggest similarities for the protoliths of the São Roque and Itaquera granites, with a possible Paleoproterozoic source (~2.9 Ga) and with \'épsilon\'\'Hf of - 22.8, indicating protracted crustal residence time. TDM ages (Sm-Nd) lie between 2.2 and 12.5 Ga, possibly representing a crustal source associated with the São Francisco paleoplate. For the other granitoids (São Roque and Jundiai domains), a more radiogenic source has to be considered, given the \'épsilon\'\'Hf (-18 to -11) and \'épsilon\' Nd (-12 to -9) values. TDM ages, and the older ages obtained with U-Pb on cores of some zircons, point to a source constituted by juvenile continental crust affected by a volcanic event (rifting) at 1.75 Ga, within the tectonic plate, forced by continental opening, or even during events that occurred close to 2.1 Ga within the São Francisco craton.
|
Page generated in 0.045 seconds