979 resultados para Igneous complex of Sines
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O estudo realizado aborda a temática "Plano de marketing: uma proposta para o Hospital do Açúcar", com direção norteadora para efetuar uma avaliação diagnóstica das atividades da Fundação Hospital da Agroindústria do Açúcar e do Álcool de Alagoas, visando proporcionar uma radiografia de sua situação e, posteriormente, plano estratégico para o desenvolvimento de um processo de gestão eficiente e eficaz. Justifica-se o presente estudo tendo em vista a importância da unidade hospitalar para o Estado de Alagoas, considerando-se sua infra¬estrutura, seus serviços prestados à comunidade alagoana, bem como possibilitar uma reorientação estratégica que possibilite otimizar suas atividades para um atendimento qualitativo e manutenção de suas atividades de forma eficiente e eficaz. Objetiva efetuar uma análise do complexo organizacional da instituição, radiografando seus pontos fortes e fracos, suas oportunidades e riscos, enfim levantando a realidade de suas atividades possibilitando a estruturação de um plano estratégico de marketing que propicie um melhor posicionamento de mercado ao hospital e que defina objetivos e metas e ser alcançados a partir da identificação de oportunidades ambientais e empresariais compatíveis com seus recursos humanos e materiais, também, levando, em consideração os seus fins a sua finalidade filantrópica, respaldada por lei. Metodologicamente, a pesquisa foi desenvolvida de natureza exploratória, objetivando proporcionar maiores informações sobre o assunto; e bibliográfica, tendo como objetivo conhecer, recolher, selecionar, analisar e interpretar as contribuições teóricas já existentes sobre o assunto. No primeiro capítulo abordará o marketing e o plano de marketing, seus conceitos e aplicações, a visualização e aplicação do marketing de serviços, a modalidade do marketing para instituições sem fins lucrativos, até chegar na estrutura e elaboração do plano de marketing. No segundo capítulo aborda o contexto do Hospital do Açúcar e Álcool de Alagoas, conceitos e definições acerca da organização hospitalar, uma abordagem histórica acerca da instituição estudada, a sua estrutura organizacional, a infraestrutura, os recursos e a realidade organizacional. No terceiro capítulo é efetuada demonstração da metodologia aplicada, considerando as duas etapas de estudo realizadas. No quarto capítulo foi efetuado uma abordagem analítica acerca do planeamento de marketing da Fundação Hospital do Açúcar, a partir da realidade encontrada, da análise de SWOT, da estratégia de marketing mix, do segmento alvo, posicionamento e tipo de concorrentes, e do plano de ação. As razões pessoas que levaram a realização do presente estudo se deve ao fato da importância da Fundação Hospital do Açúcar para o Estado de Alagoas, bem como para a população carente e consumidora dos serviços hospitalares, tendo em vista representar uma instituição tradicional e historicamente fincada na localidade, merecendo, portanto, maior atenção das autoridades e sociedade em geral. ABSTRACT; The carried through study it approaches the thematic "Marketing plan: a proposal for the Hospital of the Sugar", with norteadora direction to effect a diagnostic evaluation of the activities of the Foundation Sugar and Alcohol Hospital of Alagoas, being aimed to provide an x-ray of its situation and, later, a strategical plan for the development of a process of efficient and efficient management. The present study in view of the importance of the hospital unit for the State of Alagoas is justified, considering itself its infrastructure, its services given to the Algona community, as well as making possible a strategical reorientation that it makes possible to optimize its activities for a qualitative attendance and maintenance of its activities of efficient and efficient form. Aiming to carry out an analysis of this institution complex of the institution, being radiographed its strong and weak points, its chances and risks, at last raising the reality of its activities making possible the structure of a strategical plan in the market that propitiates one better positioning of market for the hospital and that it defines reached objectives and goals and being from the identification of compatible ambient and enterprise chances with its human resources and material, also, taking, in consideration its ends its philanthropic purpose, endorsed by law. Methodologically, the research was developed of exploratory nature, aiming to provide greaters information on the subject; bibliographical collect, to select, to analyze and theoretical contributions. ln the first chapter it will approach the marketing and the plan of marketing, its concepts and applications, the visualization and application of the marketing services, the modality of the marketing for institutions without lucrative ends, until arriving in the structure and elaboration of the marketing plan. ln as the chapter it approaches the context of the Sugar and Alcohol Hospital of Alagoas, concepts and definitions concerning the hospital organization, a historical boarding concerning the studied institution, its organizational structure, the infrastructure, the resources and the organizational reality. ln the third chapter demonstration of the applied methodology is effected, considering the two carried through stages of study. ln the room chapter an analytical boarding concerning the planning of marketing of the Foundation wich effected the Hospital of the Sugar, from the found reality, of the analysis of SWOT, the strategy of marketing mix, the white segment, positioning and type of competitors, and the plan of action. The reasons people who had taken the accomplishment of the present study to the fact of the importance of the Foundation Sugar and Alcohol Hospital of Alagoas, as well as for the devoid population and consumer of the hospital services, in view of representing a traditional institution and historicamente fincada in the locality, deserving, therefore, greater attention of the authorities and society in general.
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The purpose of this dissertation is the architectural project of the ambulatory complex of the Federal University of Pará in Belém. It is a health care establishment whose focus is sustainability, energy efficiency and humanization. This design went through the application of architectural concepts, the study of references (theorical and empirical ones), planning, examining the terrain and its conditions and the preliminay design and resulted in a preliminary architecture blueprint. The empirical research is based on the main building of the Hospital Universitário João de Barros Barreto in Belém, Hospital Sarah Kubitschek of Fortaleza (Architect João Filgueiras de Lima - Lelé) and Hospital e Maternity São Luiz of São Paulo (Architect Siegbert Zanettini). Part of the planning is based on the method "Problem Seeking of Pena and Parshal (2001)". During the development process I sought to incorporate sustainability criterias, energy efficiency and humanization. In relation to sustainability the dissertation focuses on the utilization of rainwater for non-potable usage
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Tendo por base o contexto histórico e patrimonial no qual se desenvolveu o interesse pelo património industrial em Portugal, a partir do último quartel do século passado, este trabalho procura ser um contributo para a valorização histórica e patrimonial de um espaço industrial de grandes dimensões como foi o caso do Complexo Industrial da C.U.F. no Barreiro. O trabalho estrutura-se em duas partes, na primeira parte abordamos o tema Património Industrial na sua génese e enquadramento histórico como conceito e suas perspetivas de preservação e valorização; seguidamente faremos uma pequena síntese histórica do Barreiro até ao Complexo Industrial da C.U.F., onde abordaremos também o aumento populacional e o crescimento urbano, passando pelo problema da habitação e o surgimento dos Bairros Operários até aos espaços de lazer e catividades culturais ligadas ao Operariado, não esquecendo as estruturas de saúde, assistência, lazer e as politicas sociais. Na segunda parte abordaremos a importância de valorizar o património industrial e consequentemente o Complexo Industrial com a proposta de um programa de valorização do mesmo, através da criação de núcleos museológicos e de um roteiro de Património Industrial. ABSTRACT: The Human Facet of the Industrial Complex of C.U.F.- a Heritage to Preserve The foundation of this Project is the historical heritage for which developed the interest in Portugal's industrial heritage from the last quarter of the past century. This project has the intention to contribute to the historical and heritage valorization of one of the biggest industrial complexes, which was the case of the Industrial Complex C.U.F. in Barreiro. This project has two parts, the first part will be about defining the theme of industrial heritage and its genesis and the historical setting as a concept and its perspectives of preservation and valorization; afterwards, we will do a small historical synopsis of Barreiro including the Industrial Complex of C.U.F., where we will also refer to the increase in population growth and the urban development, followed by the housing problem and consequently the increase of working class neighborhoods, even to the prices of leisure and culture activities related to the working class, not forgetting the health structures, assistance, leisure and social politics. ln the second part, we will also talk about the importance of valorizing industrial heritage, and subsequently the Industrial Complex, with a proposal of a valorization programme of the Complex with the creation of a museological core as well as an industrial heritage guide.
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Untreated effluents that reach surface water affect the aquatic life and humans. This study aimed to evaluate the wastewater s toxicity (municipal, industrial and shrimp pond effluents) released in the Estuarine Complex of Jundiaí- Potengi, Natal/RN, through chronic quantitative e qualitative toxicity tests using the test organism Mysidopsis Juniae, CRUSTACEA, MYSIDACEA (Silva, 1979). For this, a new methodology for viewing chronic effects on organisms of M. juniae was used (only renewal), based on another existing methodology to another testorganism very similar to M. Juniae, the M. Bahia (daily renewal).Toxicity tests 7 days duration were used for detecting effects on the survival and fecundity in M. juniae. Lethal Concentration 50% (LC50%) was determined by the Trimmed Spearman-Karber; Inhibition Concentration 50% (IC50%) in fecundity was determined by Linear Interpolation. ANOVA (One Way) tests (p = 0.05) were used to determinate the No Observed Effect Concentration (NOEC) and Low Observed Effect Concentration (LOEC). Effluents flows were measured and the toxic load of the effluents was estimated. Multivariate analysis - Principal Component Analysis (PCA) and Correspondence Analysis (CA) - identified the physic-chemical parameters better explain the patterns of toxicity found in survival and fecundity of M. juniae. We verified the feasibility of applying the only renewal system in chronic tests with M. Juniae. Most efluentes proved toxic on the survival and fecundity of M. Juniae, except for some shrimp pond effluents. The most toxic effluent was ETE Lagoa Aerada (LC50, 6.24%; IC50, 4.82%), ETE Quintas (LC50, 5.85%), Giselda Trigueiro Hospital (LC50, 2.05%), CLAN (LC50, 2.14%) and COTEMINAS (LC50, IC50 and 38.51%, 6.94%). The greatest toxic load was originated from ETE inefficient high flow effluents, textile effluents and CLAN. The organic load was related to the toxic effects of wastewater and hospital effluents in survival of M. Juniae, as well as heavy metals, total residual chlorine and phenols. In industrial effluents was found relationship between toxicity and organic load, phenols, oils and greases and benzene. The effects on fertility were related, in turn, with chlorine and heavy metals. Toxicity tests using other organisms of different trophic levels, as well as analysis of sediment toxicity are recommended to confirm the patterns found with M. Juniae. However, the results indicate the necessity for implementation and improvement of sewage treatment systems affluent to the Potengi s estuary
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The species Dasyatis marianae inhabits coastal areas associated with coral reefs, considered endemic to the northeast of Brazil, occurring from the State of Maranhão to the south of Bahia. Specimens of this species are commonly sighted by divers and fishermen in the area of Maracajaú reefs, a complex reef that is part of the Environmental Protection Area of Coral Reefs (EPACR), which was developed in this study about the ecology and biology of the D. marianae, in order to characterize aspects of population structure in the area of the reef complex of Parracho de Maracajaú. We analyzed 120 specimens caught by artisanal fishing site of the size, weight, sex, stage of maturity and stomach contents. Most subjects were adult males (1.7:1) and was more abundant for rays with lengths between 25 and 29cm of LD, where females reach larger sizes, a feature common to other rays. The largest specimens were captured in the area of seagrass, which is preferred for the species. The distribution of species in the area showed an ontogenetic and sexual segregation, where the youthful occur near the beach, which is a likely area for nursery and growth of the adult females prevail in the seagrass, which apparently has a high prey availability, and Adult males are more distant, a higher proportion occurring in outlying areas, suggesting a habit more exploratory than the females. The evaluation of the reproductive system indicated 3 reproductive cycles per year, one young per pregnancy, and showed that the mature males were smaller than females. The cubs of D. marianae size at birth 12 to 15cm LD. As for diet, the species was characterized as carnivorous crustacean specialist. The performance of visual censuses in different localities allowed to evaluate the density of D. marianae in different environments of the complex. The species occurs in greater numbers in seagrass, environment very important for the conservation of the species. 100 individuals of D. marianae marked in reef complex area enrolled in a recapture rate of 3%. Some behavioral aspects were evaluated, as diurnal pattern of activity, interaction with cleaning and fish Pomacanthus paru followers as Lutjanus analis and Carangoides bartholomaei. Overall, much of the information obtained should be used for management of the species
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Desde a sua identificação em 1916, até aos nossos dias, o Complexo de Arte Rupestre da Esperança foi, pontualmente e em diferentes momentos, objecto de trabalho e interpretação por parte de alguns investigadores. Este estudo visa a sistematização e compreensão das interpretações e do conhecimento produzidos ao longo de quase um século sobre a arte rupestre da freguesia da Esperança, em Arronches, complementado pelos resultados obtidos na primeira campanha de trabalhos arqueológicos realizados em 2009, no âmbito do projecto de investigação ARA- Arte Rupestre de Arronches. ABSTRACT: Since its identification in 1916 till the present day, the Rock Art Complex of Esperança was, for sometimes and in different moments, subject of specific work and interpretation by some researchers. This study aims to systematize and understand the interpretations and knowledge produced, over nearly a century, on the rock art of the Esperança parish, in Arronches, complemented by the results obtained during the first campaign of archaeological work conducted in 2009, under the research project ARA - Arronches' Rock Art.
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La ricerca di dottorato affronta lo studio della cultura materiale dell’abitato dell’età del Bronzo di Mursia (isola di Pantelleria) attraverso l’analisi della produzione ceramica. In particolare, sono analizzati gli aspetti che permettono di ampliare l’inquadramento culturale del sito, sia nella sua articolazione interna che nei rapporti con le coeve comunità del Mediterraneo centrale nella prima metà del II millennio a.C. La ricerca inizia con l’illustrazione delle recenti prospettive di studio della Preistoria del Mediterraneo, un tema al centro di un intenso dibattito incentrato sul riconoscimento delle identità culturali e sul ruolo delle reciproche interazioni, con particolare attenzione all’età del Bronzo. Al complesso archeologico di Mursia viene riconosciuto un carattere di eccezionalità per la spettacolare conservazione dei resti archeologici dell’abitato e della necropoli monumentale, oggetto di indagine negli ultimi decenni da parte dell’Università di Bologna e dell’Università Suor Orsola Benincasa di Napoli. Le ricerche hanno consentito di mettere in luce ampie porzioni dell’abitato e di poter esaminare con elevato dettaglio la cultura materiale in rapporto alle modalità insediative diversificate nello spazio e nel tempo. L’approfondimento della ricerca del dottorato verte sullo studio dei manufatti ceramici come strumento privilegiato per definire l’identità culturale della comunità di Mursia, attraverso gli aspetti della produzione artigianale, le abitudini di preparazione e consumo dei cibi e il significato funzionale o simbolico/estetico di alcune categorie vascolari. Rispetto a precedenti presentazioni del contesto di Mursia, la ricerca di dottorato ha enfatizzato, all’interno dell’abbondante produzione ceramica, la presenza di alcune classi con decorazioni incise e impresse che per quantità e caratteri di originalità divengono un elemento aggiuntivo nella definizione della facies di Mursia. Le stesse ceramiche incise e impresse presentano elementi di affinità con una serie di produzioni vascolari coeve nell’area del Mediterraneo centrale, consentendo di affrontare il tema delle interazioni tra diversi contesti insulari
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Persistent homology is a branch of computational topology which uses geometry and topology for shape description and analysis. This dissertation is an introductory study to link persistent homology and graph theory, the connection being represented by various methods to build simplicial complexes from a graph. The methods we consider are the complex of cliques, of independent sets, of neighbours, of enclaveless sets and complexes from acyclic subgraphs, each revealing several properties of the underlying graph. Moreover, we apply the core ideas of persistence theory in the new context of graph theory, we define the persistent block number and the persistent edge-block number.
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Die Arbeit schlägt eine systematische Studie der Rezeption des antiken Rom in den Werken von Heiner Müller vor. Die Analyse von Dramen, Gedichten und Essays, sowie von Interviews und Manuskripten, liefert ein umfassendes Bild wiederholter und vielschichtiger Begegnungen mit der römischen Geschichte und Literatur, die bisher weitgehend im kritischen Diskurs im Schatten standen. Der Schwerpunkt der Analyse liegt einerseits auf dem philologisch-literarischen Vergleich mit diesen Quellen und andererseits auf der darauf basierenden Rekonstruktion des umfassenden Bildes eines Imperiums, das seine historischen Grenzen überschreitet, um zu einem zivilisatorischen Prinzip zu werden, so allgegenwärtig wie ambivalent – das "Urbild" einer unauflöslichen Verschränkung von Staat und Gewalt, Kultur und Barbarei, Gesetz und Terror. Diese kulturelle Prägung zeigt sich nicht nur in Werken mit römischem Thema, sondern auch in nachfolgenden historischen Konstellationen, die Müller inszenierte, vom Elisabethanischen England über das Preußen Friedrichs II. bis hin zu den Blöcken des 20. Jahrhunderts. Besondere Aufmerksamkeit wird der Untersuchung literarischer Einflüsse und philosophischer Vorgänger dieser zivilisationskritischen Vision Roms gewidmet – eine Untersuchung, die bestehende Interpretationen korrigiert und neue einführt. Im Lichte des thematischen Komplexes "Rom" wird so ein beträchtlicher Teil von Müllers Produktion neu interpretiert, wodurch ein neues hermeneutisches Paradigma ebenso wie bisher übersehene Einflüsse und intertextuelle Beziehungen bei der Untersuchung von Dramen und Lyrik hervortreten.
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Li contents [Li] and isotopic composition (delta Li-7) of mafic minerals (mainly amphibole and clinopyroxene) from the alkaline to peralkaline Ilimaussaq plutonic complex, South Greenland, track the behavior of Li and its isotopes during magmatic differentiation and final cooling of an alkaline igneous system. [Li] in amphibole increase from < 10 ppm in Caamphiboles of the least differentiated unit to >3000 ppm in Na-amphiboles of the highly evolved units. In contrast, [Li] in clinopyroxene are comparatively low (<85 ppm) and do not vary systematically with differentiation. The distribution of Li between amphibole and pyroxene is controlled by the major element composition of the minerals (Ca-rich and Na-rich, respectively) and changes in oxygen fugacity (due to Li incorporation via coupled substitution with ferric iron) during magmatic differentiation. delta(7) Li values of all minerals span a wide range from + 17 to - 8 parts per thousand, with the different intrusive units of the complex having distinct Li isotopic systematics. Amphiboles, which dominate the Li budget of whole-rocks from the inner part of the complex, have constant delta Li-7 of + 1.8 +/- 2.2 parts per thousand (2 sigma, n = 15). This value reflects a homogeneous melt reservoir and is consistent with their mantle derivation, in agreement with published O and Nd isotopic data. Clinopyroxenes of these samples are consistently lighter, with Delta Li-7(amph-cpx). as large as 8 parts per thousand and are thus not in Li isotope equilibrium. These low values probably reflect late-stage diffusion of Li into clinopyroxene during final cooling of the rocks, thus enriching the clinopyroxene in 6 Li. At the margin of the complex delta(7) Li in the syenites increases systematically, from +2 to high values of + 14 parts per thousand. This, coupled with the observed Li isotope systematics of the granitic country rocks, reflects post-magmatic open-system processes occurring during final cooling of the intrusion. Although the shape and magnitude of the Li isotope and elemental profiles through syenite and country rock are suggestive of diffusion-driven isotope fractionation, they cannot be modeled by one-dimensional diffusive transport and point to circulation of a fluid having a high 67 Li value (possibly seawater) along the chilled contact. In all, this study demonstrates that Li isotopes can be used to identify complex fluid- and diffusion-governed processes taking place during the final cooling of such rocks. (c) 2007 Elsevier B.V All rights reserved.
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Migmatization of gabbroic rocks at 2-3 kbar has occurred in the metamorphic contact aureole of a mafic pluton in the Fuerteventura Basal Complex (Canary Island;). Migmatites are characterized by a dense network: of closely spaced millimetre-wide leucocratic veins with perfectly preserved igneous textures. They are all relatively enriched in Al, Na I: Sr Ba, Nb, Y and the rare earth elements compared with the unaffected country rock beyond the aureole. Migmatization under such low-pressure conditions war possible because of the unusual tectonic and magmatic contact in which ii occurred. Multiple basic intrusions associated with extrusive volcanic activity created high heat flow in a small area. Alkaline and metasomatized rocks present in the country rock of the intruding pluton were leached by high-temperature fluids during contact metamorphism. These enriched fluids then favoured partial melting of the host gabbroic rocks, and contaminated both the leucosomes and melanosomes. A transpressive tectonic setting at the time of intrusion created shearing along the contact between the intrusion and its host rock. This shearing enhanced circulation of the fluids and allowed segregation of the nea-formed melts from their restite by opening tension veins into which the melts migrated. Depending on the relative timing of melt segregation and recrystallization leucosomes range in composition from a 40-60% mixture of clinopyroxene (+/- amphibole) and plagioclase to almost pure feldspathic veins. Comparable occurrences of gabbros migmatized at low pressure are expected only at a snail scale in localized areas of high heat flow in the presence of fluids, such as in. mid-ocean ridges or ocean-islands.
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We present a new model to explain the origin, emplacement and stratigraphy of the Nicoya Complex in the NW part of the Nicoya Peninsula (Costa Rica) based on twenty-five years of field work, accompanied with the evolution of geochemical, vulcanological, petrological, sedimentological and paleontological paradigms. The igneous-sedimentary relation, together with radiolarian biochronology of the NW-Nicoya Peninsula is re-examined. We interpret the Nicoya Complex as a cross-section of a fragment of the Late Cretaceous Caribbean Plateau, in which the deepest levels are exposed in the NW-Nicoya Peninsula. Over 50% of the igneous rocks are intrusive (gabbros and in less proportion plagiogranites) which have a single mantle source; the remainder are basalts with a similar geochemical signature. Ar39/Ar40 radioisotopic whole rock and plagioclase ages range throughout the area from 84 to 83 Ma (Santonian) for the intrusives, and from 139 to 88 Ma (Berriasian-Turonian) for the basalts. In contrast, Mn-radiolarites that crop out in the area are older in age, Bajocian (Middle Jurassic) to Albian (middle Cretaceous). These Mn-radiolaritic blocks are set in a "matrix" of multiple gabbros and diabases intrusions. Chilled margins of magmatites, and hydrothermal baking and leaching of the radiolarites confirm the Ar39/Ar40 dating of igneous rocks being consistently younger than most of the radiolarian cherts. No Jurassic magmatic basement has been identified on the Nicoya Peninsula. We interpret the Jurassic-Cretaceous chert sediment pile to have been disrupted and detached from its original basement by multiple magmatic events that occurred during the formation of the Caribbean Plateau. Coniacian-Santonian (Late Cretaceous), Fe-rich radiolarites are largely synchronous and associated with late phases of the Plateau.
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Amphibole fractionation in the deep roots of subduction-related magmatic arcs is a fundamental process for the generation of the continental crust. Field relations and geochemical data of exposed lower crustal igneous rocks can be used to better constrain these processes. The Chelan Complex in the western U. S. forms the lowest level of a 40-km thick exposed crustal section of the North Cascades and is composed of olivine websterite, pyroxenite, hornblendite, and dominantly by hornblende gabbro and tonalite. Magmatic breccias, comb layers and intrusive contacts suggest that the Chelan Complex was build by igneous processes. Phase equilibria, textural observations and mineral chemistry yield emplacement pressures of similar to 1.0 GPa followed by isobaric cooling to 700 degrees C. The widespread occurrence of idiomorphic hornblende and interstitial plagioclase together with the lack of Eu anomalies in bulk rock compositions indicate that the differentiation is largely dominated by amphibole. Major and trace element modeling constrained by field observations and bulk chemistry demonstrate that peraluminous tonalite could be derived by removing successively 3% of olivine websterite, 12% of pyroxene hornblendite, 33% of pyroxene hornblendite, 19% of gabbros, 15% of diorite and 2% tonalite. Peraluminous tonalite with high Sr/Y that are worldwide associated with active margin settings can be derived from a parental basaltic melt by crystal fractionation at high pressure provided that amphibole dominates the fractionation process. Crustal assimilation during fractionation is thus not required to generate peraluminous tonalite.
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Turkestanite, a rare Th- and REE-bearing cyclosilicate in the ekanite-steacyite group was found in evolved peralkaline granites from the Morro Redondo Complex, south Brazil. It occurs with quartz, alkali feldspar and an unnamed Y-bearing silicate. Electron microprobe analysis indicates relatively homogeneous compositions with maximum ThO(2), Na(2)O and K(2)O contents of 22.4%, 2.93% and 3.15 wt.%, respectively, and significant REE(2)O(3) abundances (5.21 to 11.04 wt.%). The REE patterns show enrichment of LREE over HREE, a strong negative Eu anomaly and positive Ce anomaly, the latter in the most transformed crystals. Laser ablation inductively coupled plasma mass spectrometry trace element patterns display considerable depletions in Nb, Zr, Hf, Ti and Li relative to whole-rock sample compositions. Observed compositional variations suggest the influence of coupled substitution mechanisms involving steacyite, a Na-dominant analogue of turkestanite, iraqite, a REE-bearing end-member in the ekanite-steacyite group, ekanite and some theoretical end-members. Turkestanite crystals were interpreted as having precipitated during post-magmatic stages in the presence of residual HFSE-rich fluids carrying Ca, the circulation of which was enhanced by deformational events.
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Zircon recrystallization is a common process during high-grade metamorphism and promotes partial or complete resetting of the original isotopic and chemical characteristics of the mineral and thus complicates U-Pb geochronological interpretation. In Central Brazil, this complexity may be illustrated by three composite mafic-ultramafic intrusions metamorphosed under amphibolite-to-granulite conditions. Their ages of emplacement and metamorphic ages have been a matter of controversy for the last thirty years. The Serra da Malacacheta and Barro Alto complexes make up the southernmost of these layered bodies and four samples from distinct rock types were investigated in order to verify the consequences of metamorphic alteration of zircon for U-Pb dating. Cathodoluminescent imaging reveals internal features which are typical of concomitant dissolution-reprecipitation processes, such as convolute zoning and inward-moving recrystallization fronts, even in samples in which partially preserved igneous textures are observed. Due to this extensive alteration, LA-ICPMS U-Pb isotopic analysis yielded inconclusive data. However, in situ Hf isotopic and trace-element analyses help to clarify the real meaning of the geochronological data. Low Lu/Hf (<0.004) and homogeneous (176)Hf/(177)Hf(t) values imply that the zircon populations within individual samples have crystallized in a single episode, despite the observed variations in age values. Trace element signatures of zircon grains from garnet-bearing samples reveal that they were unreactive to the development of the peak metamorphism mineral assemblage and, thus, the main chemical feature in such grains is attributed to a coupled dissolution-reprecipitation process. However, in the Cafelandia amphibolite an additional alteration process is identified, probably related to the influx of late-stage fluids. Combined isotopic and geochemical investigation on zircon grains allowed the distinction of two magmatic events. The first corresponds to the crystallization of the Serra da Malacacheta Complex and characterizes a juvenile magmatism at similar to 1.3 Ga. The younger episode, recognized in the Barro Alto Complex, is dated at ca. 800 Ma and is represented by mafic and ultramafic rocks showing intense contamination with continental crust, implying that the emplacement took place, most likely, in a continental back-arc setting. Altered zircon domains as well as titanite grains date the metamorphic event at ca. 760-750 Ma. (C) 2011 Elsevier B.V. All rights reserved.