No description available.

Šiame eksperimente buvo nagrinėjama pH įtaka Cr (VI) ir Cu (II) jonų pašalinimui iš vandeninių tirpalų, naudojant metalinę geležį Fe (0), kai tirpalų pH vertės buvo nuo 2 iki 6, purtymo procese, uždaruose ir atviruose induose. Kadangi Cr (VI) ir Cu (II) jonų koncentracijų sumažėjimas tirpale priklauso nuo geležies paviršiaus, tai labai svarbu ją tinkamai paruošti: išvalyti ir aktyvuoti. Maksimalus Cr (VI) jonų pašalinimo efektyvumas buvo esant pH vertei 2, o Cu (II) jonų atveju, kai pH vertė 4 uždaruose induose ir atviruose induose – chromo atveju pH 6, vario atveju, kai pH 4. Pašalinimo įvertinimui naudojamos kalibraciniės kreivės pagal kurias apskaičiuojamos likusiųjų jonų koncentracijos, matuojant tirpalų optinius tankius. Metodas yra pigus ir patikimas, nes pašalinima didelė dalis sunkiųjų metalų jonų. / The effects of pH on Cr (VI) and Cu (II) ions removal from solutions by Fe (0) was investigated by batch shaking process. Since the presence of ferrous iron in the solution is mainly responsible for Cr (VI) and Cu (II) reduction the surface of iron must be purified and activated. The maximum Cr (VI) removal efficiency was found at pH 2 and in Cu (II) case it was pH 4 without oxygen and in case with open jar it was for Cr (vi) removal pH 6 and for Cu (II) removal pH 4. Remained concentrations of Cu (II) and Cr (VI) ions were investigated using calibrated graphs and analysis of optical density. This study confirmed that this method is cheap because we can use wasted iron and effective of removing most of heavy metal ions from solutions.

Le présent mémoire décrit la synthèse et l’utilité de complexes Cu-NHC. En premier lieu, la synthèse de complexes de cuivre porteurs de ligand(s) de type carbène-N-hétérocyclique (NHC) via une génération décarboxylative de carbènes sera présentée. En effet, de précédents rapports font état de l’utilisation de carboxylates d’imidazol(in)ium en tant que précurseurs carbéniques sous conditions thermolytiques. Ainsi, la présente étude montre l’utilisation de ces espèces zwitterioniques pour la synthèse de complexes de cuivre(I) mono- et bis-NHC comportant divers substituants et contre-ions. Une seconde partie du projet se concentrera sur l’évaluation de complexes Cu-NHC en tant que catalyseurs pour la synthèse de 2,2’-binaphtols via une réaction de couplage oxydatif de naphtols. L’objectif de ce projet de recherche est d’étudier les effets de variations structurales de différents complexes Cu-NHC afin de construire un processus catalytique plus efficace. Les effets de la structure du catalyseur sur la réaction de couplage ont été évalués en variant son contre-ion, le nombre de ligands NHC se coordonnant au cuivre, ainsi que la nature des substituants du ligand. / The present thesis describes the synthesis and utility of NHC-Cu complexes. First, the synthesis of N-heterocyclic carbene (NHC) copper complexes via the decarboxylative generation of carbenes is presented. Indeed, literature precedents reported that imidazol(in)ium-2-carboxylates may be used as carbene precursors under thermolytic conditions. As such, the present study demonstrates how zwitterionic carboxylates may be utilized in the formation of both mono- and bis-NHC Cu complexes with various substitution patterns and counterions. Secondly, the NHC-Cu complexes were evaluated for the synthesis of 2,2’-binaphthols via the oxidative coupling of naphthol derivatives. The objective of the study was to investigate how structural variations to various NHC-Cu catalysts may generate a more efficient catalytic process. Effects of the structure of the catalyst on the coupling reaction have been studied by varying the number of NHC ligands coordinating to Cu, as well as the nature of the NHC ligand substituents and the counterions.

This article has been published online on 21st May 2014, in Journal of Vacuum Science & Technology A: Vac (Vol.32, Issue 4): http://scitation.aip.org/content/avs/journal/jvsta/32/4/10.1116/1.4878815?aemail=author DOI: 10.1116/1.4878815 This article may be accessed via the issue's table of contents at this link: http://scitation.aip.org/content/avs/journal/jvsta/32/4?aemail=author The surface chemistry of the bis(tri-n-butylphosphane) copper(I) acetylacetonate, [(nBu3P)2Cu(acac)], and the thermal atomic layer deposition (ALD) of Cu2O using this Cu precursor as reactant and wet oxygen as co-reactant on SiO2 substrates are studied by in-situ X-ray photoelectron spectroscopy (XPS). The Cu precursor was evaporated and exposed to the substrates kept at temperatures between 22 °C and 300 °C. The measured phosphorus and carbon concentration on the substrates indicated that most of the [nBu3P] ligands were released either in the gas phase or during adsorption. No disproportionation was observed for the Cu precursor in the temperature range between 22 °C and 145 °C. However, disproportionation of the Cu precursor was observed at 200 °C, since C/Cu concentration ratio decreased and substantial amounts of metallic Cu were present on the substrate. The amount of metallic Cu increased, when the substrate was kept at 300 °C, indicating stronger disproportionation of the Cu precursor. Hence, the upper limit for the ALD of Cu2O from this precursor lies in the temperature range between 145 °C and 200 °C, as the precursor must not alter its chemical and physical state after chemisorption on the substrate. 500 ALD cycles with the probed Cu precursor and wet O2 as co reactant were carried out on SiO2 at 145 °C. After ALD, in situ XPS analysis confirmed the presence of Cu2O on the substrate. Ex-situ spectroscopic ellipsometry indicated an average film thickness of 2.5 nm of Cu2O deposited with a growth per cycle of 0.05 Å/cycle. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) investigations depicted a homogeneous, fine, and granular morphology of the Cu2O ALD film on SiO2. AFM investigations suggest that the deposited Cu2O film is continuous on the SiO2 substrate.

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-04-04T20:26:12Z No. of bitstreams: 1 ALANA PEREIRA RAMOS - DISSERTAÇÃO PPG-CEMat 2014..pdf: 2592489 bytes, checksum: 5e82ab454a76e1050981da9019ce8fec (MD5) / Made available in DSpace on 2018-04-04T20:26:12Z (GMT). No. of bitstreams: 1 ALANA PEREIRA RAMOS - DISSERTAÇÃO PPG-CEMat 2014..pdf: 2592489 bytes, checksum: 5e82ab454a76e1050981da9019ce8fec (MD5) Previous issue date: 2017-08-07 / As ligas ternárias de Ti-Cu-Ni com memória de forma são conhecidas por apresentarem transformação de fase característica e propriedades semelhantes às ligas binárias Ti–Ni. Estudos realizados com ligas ricas em cobre mostraram que a adição de cobre nas ligas de Ti-Ni reduz a histerese de resposta do efeito de memória de forma e aumenta a TFA (tendência de formação de fase amorfa) ainda pouco estudada com altas porcentagens de cobre. Diante disso, este trabalho teve como objetivo avaliar a influência da velocidade de resfriamento nas temperaturas de transformação e na tendência de amorfização em fitas de Ti-CuNi resfriadas rapidamente. Para tanto, foram produzidas duas fitas Ti01 (Ti 43,5 Cu 37,8 Ni 18,7) e Ti02 (Ti 58,4 Cu 25,6 Ni 16,0) pelo processo melt spinning, variando-se a velocidade linear da roda em 21 m/s e 63 m/s. As amostras foram caracterizadas utilizando-se técnicas DSC, DR-X, RET e MO. Após essa caracterização pode-se afirmar que a técnica de melt spinning permite a produção de fitas muito finas, da ordem de micrômetros, em apenas uma etapa de processamento, assim como também foi possível a produção de fitas amorfas, do sistema Ti-Cu-Ni, sem nenhuma fase cristalina como observado na fita Ti01 e Ti 02 obtidas com velocidade linear de 63m/s. O tratamento térmico foi suficiente para remover todos os defeitos produzidos pelo processo de solidificação rápida e produzir um rápido crescimento de grão, favorecendo o aumento das temperaturas de transformação martensíticas e austeníticas. / Ternary alloys with shape memory Ti-Cu-Ni are known to submit a characteristic phase transformation and properties similar to the and Ti-Ni binary alloy . Studies with rich-copper alloys showed that the addition of copper in alloys Ti-Ni reduces the hysteresis response of the shape memory effect and increases the TFA (tendency to form amorphous phase) still little studied with high percentages of copper. Thus, this study aimed to evaluate the influence of cooling rate on the transformation temperatures and on the tendency of Cu-Ni-Ti ribbons rapidly solidified. Therefore, two ribbons TI01 (Ti 43.5 Cu 37.8 Ni 18.7) and Ti02 (Ti 58.4 Cu 25.6 Ni 16.0) were produced by melt spinning process, varying the wheel linear velocity 21 m/s and 63 m/s. The samples were characterized using DSC, X-DR, RET and MO and techniques. Melt spinning technique allows the production of very thin ribbons of the order of microns, in one processing step, as it was also possible to produce amorphous ribbons, the system Ti-Cu-Ni, without crystalline phase as observed in TI01 and 02 Ti02 with linear velocity of 63m/s. The heat treatment was sufficient to remove all defects produced by rapid solidification process and produce a rapid grain growth, favoring the increase of temperatures of martensitic and austenitic transformation.

Made available in DSpace on 2014-12-17T14:06:48Z (GMT). No. of bitstreams: 1 WersonMC.pdf: 1184207 bytes, checksum: f2f0598e463a68730749344c713c5bff (MD5) Previous issue date: 2008-02-22 / The Tungsten/copper composites are commonly used for electrical and thermal objectives like heat sinks and lectrical conductors, propitiating an excellent thermal and electrical conductivity. These properties are dependents of the composition, crystallite size and production process. The high energy milling of the powder of W-Cu produces an dispersion high and homogenization levels with crystallite size of W very small in the ductile Cu phase. This work discusses the effect of the HEM in preparation of the W-25Cu composite powders. Three techniques of powder preparation were utilized: milling the dry with powder of thick Cu, milling the dry with powder of fine Cu and milling the wet with powder of thick Cu. The form, size and composition of the particles of the powders milled were observed by scanning electron microscopy (SEM). The X-ray diffraction (XRD) was used to analyse the phases, lattice parameters, size and microstrain of the crystallite. The analyse of the crystalline structure of the W-25Cu powders milled made by Rietveld Method suggests the partial solid solubility of the constituent elements of the Cu in lattice of the W. This analyse shows too that the HEM produces the reduction high on the crystallite size and the increase in the lattice strain of both phases, this is more intense in the phase W / Os comp?sitos de Tungst?nio/Cobre (W-Cu) s?o geralmente usadas para fins el?tricos e t?rmicos como dissipadores de calor e condutores el?tricos, devido as suas excelentes propriedades de condutividades t?rmica e el?trica. Essas propriedades s?o dependentes da composi??o, do tamanho de cristalito e principalmente do processo de fabrica??o. A moagem de alta energia de p?s W-Cu produz alto n?vel de homogeneiza??o e dispers?o com cristalitos de W muito fino na fase d?ctil Cu. Este trabalho discute o efeito da MAE na prepara??o dos p?s comp?sitos W-25Cu. Tr?s t?cnicas de prepara??o dos p?s foram utilizadas: moagem a seco com p? de Cu grosso, moagem a seco com p? de Cu fino e moagem a ?mido com p? de Cu grosso. A forma, tamanho e a composi??o das part?culas dos p?s mo?dos foram observadas por microsc?pio eletr?nico de varredura (MEV). A difra??o de raios-X(DRX) foi usada para observar as fases, par?metros de rede, tamanho e microtens?o dos cristalitos. A an?lise da estrutura cristalina dos p?s mo?dos de W-25Cu feita pelo m?todo de Rietveld sugere uma solubilidade s?lida parcial dos elementos constituintes do cobre (Cu) na rede do tungst?nio (W). Essa an?lise tamb?m mostra que a MAE produz uma alta redu??o no tamanho dos cristalitos e um aumento de tens?o na rede de ambas as fases, isto ocorre com maior intensidade na fase do W

La thèse porte sur les propriétés thermodynamiques, de transport, de diffusion de rayonnement, et diélectriques des mélanges CO2-N2 contaminés par du cuivre, pour des températures de 300 - 30,000 K et des pressions 0.1 - 16 bar. Les motivations de ce travail ainsi qu'un état de l'art sur le remplacement du SF6 et l'influence des vapeurs métalliques dans de tels dispositifs sont présentés dans le chapitre 1. Le chapitre 2 étudie les compositions à l'équilibre calculées à partir de la méthode de minimisation de l'énergie libre de Gibbs, en considérant la présence de phases condensées dans le plasma. A partir de ces compositions, nous présentons les propriétés thermodynamiques comme la densité de masse, l'enthalpie et la chaleur spécifiques à pressions constante. Les corrections de Virial et Debye-Hückel sont prises en compte pour tenir compte de l'effet des ions et des hautes pressions. Dans le chapitre 3, les coefficients de transport (conductivité électrique, viscosité, et conductivité thermique) et les coefficients de diffusion combinés (coefficients de diffusion ordinaires combinés, ceux liés au champ électrique, aux gradients de pression et de température) sont calculés selon la théorie de Chapman-Enskog. Les intégrales de collision nécessaires au calcul de ces coefficients sont obtenues pour les interactions neutre-neutre et neutre-ion à partir d'un potentiel de Lennard-Jones modifié. Dans le chapitre 4, les coefficients d'émission nette (CEN) sont calculés en considérant le rayonnement des raies atomiques, du continuum atomique, des raies moléculaires et du continuum moléculaire. Les élargissements en pression des raies (élargissements de Van der Waals et de résonance), les élargissements Stark, et l'élargissement sont pris en compte dans la détermination d'un facteur de fuite qui permet de simplifier le calcul du coefficient d'émission des raies. Le rayonnement du continuum atomique tient compte de l'attachement radiatif, de la recombinaison radiative et du Bremsstrahlung. Dans le chapitre 5, les propriétés diélectriques de claquage (incluant la fonction de distribution d'énergie des EEDF), le coefficient réduit d'ionisation réduit, le coefficient réduit d'attachement électronique, le coefficient effectif réduit d'ionisation, et le champ critique réduit) du gaz chaud ont été calculés sur la base de l'approximation à deux termes de l'équation de Boltzmann. Les interactions, incluant les collisions élastiques, excitation, ionisation et attachement entre électrons et espèces neutres sont pris en compte dans la résolution de l'équation de Boltzmann. Les sections efficaces d'ionisation de Cu2 et CuO non disponibles dans la littérature ont été calcules selon la méthode DM. La conclusion des travaux et leurs perspectives sont présentés dans le chapitre. / Sulfur hexafluoride (SF6) is a greenhouse gas designated by the Kyoto Protocol because of its extremely high global warming potential (GWP). CO2, N2, and their mixtures have the potential to replace SF6 in certain applications, such as circuit breakers. In these electric apparatus, copper vapour resulting from the heating of electrodes can modify the characteristics of arc plasmas, which must be taken into account when setting up physical models. This dissertation, therefore, investigates the thermodynamic, transport, diffusion, radiation, and dielectric breakdown properties of CO2-N2 mixtures contaminated by copper at temperatures of 300 - 30,000 K and pressures of 0.1 - 16 bar. The equilibrium compositions are calculated using the minimization of Gibbs free energy with consideration of condensed species. Copper vapour is found to condense at temperatures below 3000 K. Based on the compositions, the thermodynamic properties, including mass density, specific enthalpy, and specific heat at constant enthalpy, are determined according to their definitions. The Debye-Hückel corrections are also considered in the calculation of compositions and thermodynamic properties. The transport coefficients (including electrical conductivity, viscosity, thermal conductivity) and combined diffusion coefficients (including the combined ordinary diffusion coefficient, combined electric field diffusion coefficient, combined temperature diffusion coefficient and combined pressure diffusion coefficient) are calculated based on the Chapman-Enskog theory. The newly developed Lennard-Jones like phenomenological model potential is adopted to describe the neutral-neutral and neutral-ion interactions in determining collision integrals. The net emission coefficients (NEC) of gas mixtures are calculated with considering atomic lines and continuum and molecular bands and continuum. The pressure broadening (Van der Waals broadening and the resonance broadening), Stark broadening, and Doppler broadening are taken into account in the determination of escape factors. The continuum radiation of atoms is described by radiative attachment, radiative recombination, and Bremsstrahlung. The dielectric breakdown properties (including EEDF, reduced ionization coefficient, reduced electron attachment coefficient, reduced effective ionization coefficient, and reduced critical electric field strength) of hot gas mixtures are calculated based on the two-term approximation of the Boltzmann equation. The interactions, including elastic, excitation, ionization and attachment collisions, between electrons and neutral species are taken into account in solving the Boltzmann equation. The ionization cross sections of Cu2 and CuO which are unavailable in literatures are calculated using the DM method. Compared with SF6-Cu mixtures, CO2-N2-Cu mixtures present much different thermophysical, radiation, and dielectric breakdown properties. As an arc quenching gas, CO2-N2-Cu mixtures have lower ??Cp and thermal conductivity at low temperatures but present higher ??Cp, thermal conductivity, and NEC in the medium temperature range. As an insulating medium, the hot CO2-N2-Cu mixtures have much poorer dielectric strength below 2000 K, whereas above 2000 K, they present better dielectric breakdown performance than SF6-Cu mixtures.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work elaborates on the determination of crystal and molecular structures of four pro-ligands, emphasizing bis(triazenes), triazene 1-oxide and a new class of bis(triazenes) macrocyclic, and eight complexes involving Cu+, Cu2 +, Ni2 + and K+. Pro-ligands triazenes 1-oxide are relatively small and simple molecules. When they are deprotonated they presen a high ability to form supramolecular assemblies, either because they are planar and facilitate the metal-metal approach and the formation of π···π interactions _ as in the case of complex (2) _, or because they have substituents with capacity of act as agent of secondary complexation forming polycationic structures _ as in the case of complex (3). Pro-ligand bis(triazenes) are double agents of complexation. The bis(triazene) (4) complexed Copper(I) forming a binuclear complex (5). The same ligand also led to binuclear complexes of Copper(II) through the chelate and macrocyclic effect, forming two types of crystal structures, one non-centrosymmetric (6), the other centrosymmetric (7). The pro-ligand bis(triazene) macrocyclic (8) has a cavity with ideal size for the complexation of transition metals, resulting, for example, in complex (9) with the cation Nickel(II). The ligand in this complex has substituents in para position. These substituents, two pyridine molecules (in the coordination sphere of the metal) and two pyridine molecules (as solvate of crystallization) form weak electrostatic interactions in the supramolecular arrangement. The bis(triazene) macrocyclic (10) has a central cavity larger than the bis(triazene) macrocyclic (8), allowing the complexation of larger molecules or ions. The analysis by X-ray diffraction on single crystal for the compound (10) revealed the presence of disordered water molecules inside the cavity, forming a chain of water molecules perpendicular to the stacked molecules of (10). When the compound (10) is deprotonated with a weak base such as pyridine, the deprotonation occurs partially, leading to a binuclear complex with Copper(II)-bridged μ2-OH (11). Two molecules of the ligand coordinate the two Copper(II) cations, and the coordination sphere is completed by two axial pyridine molecules. When the compound (10) is deprotonated with a strong base such as sodium or potassium ethanolate, the deprotonation occurs totally, leading to a binuclear conmplex with Copper(II)-bridged μ2-OCH2CH3 (12). One molecule ligand coordinates two Copper(II) cations and the coordination sphere is also supplemented by two axial pyridine molecules. The synthesis of a new class of macrocyclic triazenes has been successfully performed as well as the synthesis of their metallic complexes. The characterization of their structures and supramolecular assemblies was performed using the analysis by X-ray diffraction on single crystal and other secondary methods. / Este trabalho apresenta as determinações das estruturas cristalinas/moleculares de quatro pró-ligantes, enfatizando bis(triazenos), triazeno 1-óxido e a nova classe de bis(triazenos) macrocíclicos, e oito complexos envolvendo os cátions Cu+, Cu2+, Ni2+ e K+. Pró-ligantes triazenos 1-óxido são moléculas relativamente pequenas e simples, que quando desprotonadas apresentam elevada capacidade de formação de arranjos supramoleculares, sejam pelo fato de serem planares e facilitarem a aproximação metal-metal e a formação de interações π···π, como no caso do complexo (2), ou pelo fato de apresentarem substituintes capazes de atuarem como complexantes secundários, formando estruturas policatiônicas complexas, como no caso do complexo (3). Pró-ligantes bis(triazenos) são agentes duplos de complexação. O bis(triazeno) (4) mostrou-se capaz de complexar o íon cobre(I) formando um complexo binuclear (5). O mesmo ligante, ainda, originou complexos binucleares de cobre(II), através do efeito quelato e macrocíclico, formando dois tipos de estruturas cristalinas, uma não-centrossimétrica (6) e outra centrossimétrica (7). O pró-ligante bis(triazeno) macrocíclico (8) apresenta uma cavidade com tamanho ideal para a complexação de metais de transição, originando, por exemplo, o complexo (9) com o cátion níquel(II). O ligante neste complexo apresenta substituintes em posição para e estes subtituintes, adicionados às moléculas de piridina que completam a esfera de coordenação do metal e às moléculas de piridina como solvato de cristalização, formam o arranjo supramolecular, através de interações eletrostáticas fracas. O pró-ligante bis(triazeno) macrocíclico (10) apresenta uma cavidade central maior que o pró-ligante bis(triazeno) macrocíclico (8), possibilitando a complexação de moléculas ou cátions maiores. A difração de raios-x em monocristal de (10) revelou a presença de moléculas de água desordenadas no interior da cavidade, formando uma cadeia perpendicular às moléculas empacotadas do pró-ligante macrocíclico. Quando o composto (10) é desprotonado com base fraca, como piridina, a desprotonação ocorre de maneira parcial, originando um complexo binuclear de cobre(II) unido por pontes μ2-OH (11), onde duas moléculas de ligante coordenam os dois íons cobre(II) e a esfera de coordenação quadrática é completada por duas moléculas de piridina axiais. Quando o composto (10) é desprotonado com base forte, como etóxido de sódio ou potássio, a desprotonação ocorre de maneira total, originando um complexo binuclear de cobre(II) unido por pontes μ2-OCH2CH3 (12), onde uma molécula de ligante coordena os dois íons cobre(II) e a esfera de coordenação quadrática também é completada por duas moléculas de piridina axiais. A síntese de mais representantes da nova classe de triazenos macrocíclicos foi realizada com sucesso neste trabalho, bem como a síntese de complexos, envolvendo triazenidos macrocíclicos. A caracterização de suas estruturas e arranjos supramoleculares foi realizada através de difração de raios-x em monocristal e outros métodos secundários.

Orientadores: Roberto Perez Xavier, Lena Virginia Soares Monteiro / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociencias / Made available in DSpace on 2018-08-14T22:53:15Z (GMT). No. of bitstreams: 1 Torresi_Ignacio_M.pdf: 10387814 bytes, checksum: 10ae1f36fa8d66f6046d5f1bb6d6a4aa (MD5) Previous issue date: 2009 / Resumo: O depósito de óxido de ferro-cobre-ouro (IOCG) Alvo 118 (170 Mt @ 1,0 wt% Cu, 0,3 g/t Au), junto aos depósitos de classe mundial de Sossego e Cristalino, situam-se no setor sul da Província Mineral de Carajás (PMC) alinhados e uma zona de cisalhamento subvertical regional, de direção WNW-ESE, e 60 km de extensão, próximo ao contato do Supergrupo Itacaiunas, uma sequência metavulcano-sedimentar (~2,76 Ga), com o embasamento arqueano (Complexo Xingu; ~3,0 Ga). A mineralização de Cu-Au no deposito Alvo118 e hospedada por rochas vulcanicas máficas e intermediarias, corpos de granitos e gabbros, que foram sujeitos a seguinte sequência de alteração hidrotermal em direção ao minério de Cu: (1) alteração sódica representada por albita e escapolita, o que indica circulação de fluidos quentes (>500°C) e salinos; (2) alteração potássica dominada pela presença de biotita e k-feldspato, respectivamente, nas rochas máficas e intermediarias, acompanhada de formação de magnetita e silicificação; (3) alteração a clorita, espacialmente associada brechas quartzo-carbonaticas mineralizadas a calcopirita e stockworks de veios que normalmente apresentam estruturas de preenchimento de espaço; (4) alteração a quartzo-sericita tardia a mineralizacao. A assembléia mineral da mineralizacao e dominada por calcopirita (80%), acompanhado de bornita (10%), magnetita (10%), hematita (10%), e traços de teluretos de Au-Ag, galena e cassiterita. Diferente de outros depósitos do tipo IOCG da PMC, onde ETRL estão presentes em apatita, allanita e monazita, no Alvo 118 o enriquecimento e em ETRP. Neste deposito os ETRP estão concentrados principalmente em apatite e em um mineral pobre em alumínio, um silicato de Be-B-ETRP do grupo da gadolinite, que nunca foi descrita em qualquer deposito do tipo IOCG do mundo. Estudos de inclusões fluidas em quartzo e calcite apontam pra um regime de fluidos, em que soluções hipersalinas e quentes, representada por inclusões trifásicas, fossem progressivamente esfriadas e diluídas por fluidos de baixa salinidade, representada por inclusões bifásicas, que dominam na mineralizacao do Alvo 118. Valores de d18OH2O em equilíbrio com calcita (-1.9¿ a 10.7¿ a 300°C) sugerem forte interação entre os fluidos mineralizantes e as rochas hospedeiras, como também prolongada mistura com fluidos meteóricos. A composição de d34S em calcopirita (5.1¿ a 6.3¿) difere daquela de fonte mantélica/magmática, reforçando a possibilidade de fontes de enxofre mais pesado (sulfatos de evaporitos?) para os sulfetos da brecha e dos veios mineralizados. A alteração sódica de alta temperatura, a sobreposição de alteração potássica e a alteração a clorita proximal, a brecha de quartzo-carbonatica mineralizada e os valores de d18O indicam que o Alvo 118 e um sistema IOCG que evoluiu em níveis estruturais superiores, nível crustal raso, envolvendo o influxo de águas meteóricas. / Abstract: The Alvo 118 iron oxide-copper-gold (IOCG) deposit (170 Mt @ 1,0 wt% Cu, 0,3 g/t Au), together with the world-class Sossego and Cristalino deposits, lie in the southern sector of the Carajas Mineral Province (CMP) along a steeply-dipping, WNW-ESE-striking, 60 km-long shear zone, close to the contact of the Itacaiunas Supergroup metavolcano-sedimentary sequence (~2,76 Ga) and the basement (Xingu Complex; ~3,0 Ga). The Cu-Au mineralization at the Alvo 118 is hosted by mafic and felsic metavolcanic rocks and crosscutting granitoid and gabbro bodies that have been subjected to the following hydrothermal alteration sequence towards the ore zones: (1) sodic alteration represented by albite and scapolite, indicating the circulation of hot (>500°C) and highly saline fluids; (2) potassium alteration dominated by biotite or Kfeldspar, respectively, in mafic and felsic volcanic and intrusive rocks, accompanied by the formation of magnetite and silicification; (3) chlorite alteration spatially associated with carbonate-quartz ore breccia and vein stockworks that commonly display open-space filling textures; (4) local post-ore quartz-sericite alteration. The ore assemblage is dominated by chalcopyrite (80%), accompanied by bornite (10%), magnetite (10%), hematite (10%), and traces of Au-Ag tellurides, galena and cassiterite. Dissimilar from other IOCG deposits of the CMP where LREEs are commonly enriched in apatite, allanite and monazite, the Alvo 118 ore displays enrichments of HREEs. In this deposit the HREEs are mainly concentrated in apatite and in an Al-poor, Be-B-HREE silicate of the gadolinite group which has never been reported in IOCG systems worldwide. Fluid inclusion studies in quartz and calcite point to a fluid regime in which hot brine solutions, represented by < 10 vol.% of salt-bearing aqueous inclusions, were progressively cooled and diluted by lower temperature, low-salinity (< 10 wt% NaCl eq.) aqueous fluids defined by two-phase aqueous inclusions, by far the dominant type. d18OH2O values in equilibrium with calcite (- 1.9¿ to 10.7¿ at 300°C) suggest strong interaction between ore fluids and the host rocks, as well as prolonged mixing with meteoric fluids. The d34S composition of chalcopyrite (5.1¿ to 6.3¿) differs from a mantle/magmatic source adding the possibility of heavier sulfur sources (e.g., evaporite sulfate?) for the ore breccia and vein sulfides. The restricted high temperature sodic alteration, the pervasive overprinting of the potassic alteration minerals (biotite and K-feldspar) by chlorite proximal to the ore zones, quartz-calcite-chlorite ore breccias/veins with open-space filling textures in brittle structures, and the d18O data collectively indicate that the Alvo 118 IOCG system developed at structurally high levels and experienced the influx of evolved meteoric water. / Mestrado / Mestre em Geociências

Orientadores: Lena Virginia Soares Monteiro , Roberto Perez Xavier / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociências / Made available in DSpace on 2018-08-15T15:13:25Z (GMT). No. of bitstreams: 1 Moreto_CarolinaPenteadoNatividade_M.pdf: 6364154 bytes, checksum: 08d26b0642844f0ebe0c97e4f6816d34 (MD5) Previous issue date: 2010 / Resumo: O depósito de óxido de ferro-cobre-ouro Bacaba, situado no Cinturão de Cisalhamento Itacaiúnas, Província Mineral de Carajás, representa um alvo satélite do depósito de classe mundial Sossego, e possivelmente também representa as porções distais e profundas do mesmo sistema hidrotermal. O depósito Bacaba localiza-se ao longo de uma zona de cisalhamento com direção WNW-ESE que define o contato entre o embasamento, representado pelo Complexo Xingu (ca. 3,0 Ga), e a unidade metavulcano-sedimentar do Supergrupo Itacaiúnas (ca. 2,76 Ga). As principais rochas hospedeiras do minério no depósito Bacaba são representadas pelo Granito Serra Dourada, Tonalito Bacaba e por corpos gabróicos, que foram intensamente afetados por alterações hidrotermais sódica (albita-escapolita), potássica, clorítica e hidrolítica. Os dados de U-Pb LA-ICP-MS em zircão de uma amostra com alteração sódica do Granito Serra Dourada forneceram a idade de 2858 ± 30 Ma (MSWD = 9,7). Três amostras do Tonalito Bacaba, sendo uma com alteração potássica e duas com alteração potássica e mineralização de Cu-Au, forneceram idades em 2997,2 ± 4,7 Ma (MSWD = 1,15), 2993,1 ± 7,1 Ma (MSWD = 1,1) e 3004,7 ± 7,8 Ma (MSWD = 2,1), respectivamente. As idades em 2,86 e ca. 3,0 Ga são interpretadas como idade de cristalização do Granito Serra Dourada e do Tonalito Bacaba, respectivamente. As estruturas internas e morfologia dos cristais de zircão de ambas as rochas, observadas em imagens de catodoluminescência e de elétrons retro-espalhados, confirmam a ocorrência de processos de recristalização, que pode ser relacionado com episódios de hidrotermalismo e/ou deformação/metamorfismo que ocorreram na Província Mineral de Carajás. Contudo, esse (s) evento (s) não pode (puderam) ser datado (s) devido à ausência de abertura total do sistema isotópico U-Pb e ausência de cristais de zircão de origem hidrotermal.O Granito Serra Dourada e o Tonalito Bacaba são as rochas graníticas mais antigas até então reconhecidas no Cinturão de Cisalhamento Itacaiúnas. A presença dessas rochas tão antigas implica na existência de um importante magmatismo anterior à instalação da Bacia de Carajás (Supergrupo Itacaiúnas), e em uma história evolutiva mais complexa para o Cinturão de Cisalhamento Itacaiúnas. As similaridades petrográficas e geocronológicas dessas intrusivas félsicas do depósito Bacaba com suítes de rochas graníticas e tonalíticas reconhecidas no Terreno Granito-Greenstone Rio Maria, porção sul da Província Mineral de Carajás, implica na ocorrência de um magmatismo de ca. 3,0 e 2,86 Ga mais amplo e extenso. O Granito Serra Dourada e o Tonalito Bacaba não poderiam ser responsáveis pelo estabelecimento do sistema magmático-hidrotermal associado com a gênese do depósito Bacaba. Isso seria improvável porque outros depósitos com características similares são hospedados por unidades metavulcano-sedimentares mais novas (2,76 Ga). Nesse contexto, os depósitos de óxido de ferro-cobre-ouro do setor sul do Cinturão de Cisalhamento Itacaiúnas devem ser controlados principalmente por importantes descontinuidades crustais, como a zona de cisalhamento regional com direção WNW-ESE, ao invés de serem associados com um litotipo particular. Esses resultados indicam alto potencial de ocorrência de depósitos de óxido de ferro-cobre-ouro nas rochas mesoarqueanas do embasamento sob a Bacia de Carajás, particularmente aquelas cortadas por zonas de cisalhamento neoarqueanas. / Abstract: The Bacaba iron oxide-copper-gold deposit, situated in the Itacaiúnas Shear Belt, Carajás Mineral Province (Brazil), represents a satellite prospect of the world-class Sossego deposit, and might also represent a distal and deeper portion of the same or related hydrothermal system. The Bacaba deposit is located along a WNW-ESE-striking shear zone that defines the contact of the basement represented by the Xingu Complex (ca. 3.0 Ga) and the metavolcanosedimentary Itacaiúnas Supergroup (ca. 2.76 Ga). The main host rocks at Bacaba deposit comprise the Serra Dourada Granite, the Bacaba Tonalite and croscutting gabbro, which were intensely affected by sodic (albite-scapolite), potassic, chloritic and hydrolytic hydrothermal alterations. The U-Pb LA-ICP-MS data for zircon from sodic altered sample of the Serra Dourada Granite yielded an 2858 ± 30 Ma (MSWD = 9.7) age. Three samples from the Bacaba Tonalite, including one with potassic alteration and two with potassic alteration and Cu-Au mineralization rendered the 2997.2 ± 4.7 Ma (MSWD = 1.15), 2993.1 ± 7.1 Ma (MSWD = 1.1) and 3004.7 ± 7.8 Ma (MSWD = 2.1) ages, respectively. The 2.86 and ca. 3.0 Ga ages are interpreted as the igneous crystallization of the Serra Dourada Granite and the Bacaba Tonalite, respectively. The internal structures and external morphologies of zircon crystal from both rocks, observed in cathodoluminescence and backscattered electron images, attested the occurrence of zircon recrystallization, which could be related to hydrothermalism and/or deformation/metamorphism episodes that took place in the Carajás Mineral Province. However, the disturbing event (s) could not be dated due to the absence of the total resetting of the U-Pb system and hydrothermal crystallization of zircon. The 2.86 Ga Serra Dourada Granite and the ca. 3.0 Ga Bacaba Tonalite are the oldest granitic rocks so far recognized in the Itacaiúnas Shear Belt. The presence of such old rocks implies in the existence of an important magmatism before the Carajás Basin (Itacaiúnas Supergroup) deposition, and in a more complex evolutionary history for the Itacaiúnas Shear Belt. The petrographical and geochronological similarities of these felsic intrusions with granitic and tonalitic rock suites recognized in the Rio Maria granite-greenstone terrane, southern part of the Carajás Mineral Province, implies in a more widespread ca. 3.0 and 2.86 Ga magmatism in the province. The Serra Dourada Granite and the Bacaba Tonalite are interpreted not to be responsible for the genesis of the Bacaba deposit. This is likely because the Sossego and other deposits interpreted as part of the same hydrothermal system are hosted by younger ca. 2.76 Ga metavolcano-sedimentary units. On this context, the iron oxide-copper-gold deposit in the southern sector of the Itacaiúnas Shear Belt could be mainly controlled by important crustal discontinuities, such as the WNW-ESEstriking regional shear zone, rather than be associated with a particular rock type. These results expand the potentiality of occurrence of iron oxide-copper-gold deposits for the Mesoarchean basement rocks underlying the Carajás Basin, particularly those crosscut by Neoarchean shear zones. / Mestrado / Geologia e Recursos Naturais / Mestre em Geociências