Dissertations / Theses: 'Petrology'

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Amaral, Paulo Giovany Quadros do [UNESP]. "Caracterização radiométrica e de exalação de Radônio em rochas ornamentais silicáticas beneficiadas no Estado do Espírito Santo." Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/92886.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
O trabalho realizou avaliações relativas ao comportamento radiométrico e de exalação do gás radônio em rochas ornamentais e de revestimento exploradas nos estados brasileiros de Minas Gerais e Espírito Santo. Sabendo que as rochas apresentam em sua constituição determinados teores de elementos radioativos tais como 87Rb, 40K, 238U, 235U e 232Th, sendo os três últimos a gerar em suas séries por decaimento o Rn e, apesar da baixa concentração natural do mesmo nos diversos ambientes e de sua curta meia vida de 3,8 dias, adquire importância pelo fato de seu decaimento gerar os elementos metálicos 218Po, 214Pb, 214Bi e 214Po que podem se fixarem nos pulmões causando patologias importantes nas vias respiratórias, especificamente na indução de metástases. Devido à importância de conhecer as concentrações do gás radônio nos ambientes de convívio humano foram escolhidas 10 rochas silicáticas de variedade geológica e de destaque comercial beneficiadas por empresas de Cachoeiro de Itapemirim – ES, compreendendo rochas magmáticas dadas por diorito, sienito, charnockito, monzogranito e três pegmatitos graníticos e por três rochas metamórficas. O estudo, envolvendo os dados radiométricos de U, Th, K e de monitoramento de exalação do gás 222Rn, revela uma boa correlação entre os parâmetros petrográficos e índices físicos das rochas. Os teores de U variaram de 2,9 ppm a 37 ppm e Th de 0,3 ppm a 84 ppm, mostrando que as concentrações destes radionuclídeos característicos para cada tipo de rocha, revelam a perfeita coerência entre a presença ou ausência de minerais acessórios detentores de elementos radioativos. A quantidade de exalação de radônio fornecida pelas rochas está diretamente relacionada aos aspectos petrográficos de cada material, principalmente ao grau e tipos de...
This work carried out assessments on the radiometric behavior and exhalation of radon gas in dimensional and surfacing stones exploited in the Brazilian states of Minas Gerais (MG) and Espírito Santo (ES). The rocks usually contain different levels of the radionuclides 87Rb, 40K, 238U, 235U and 232Th, the last three forming radioactive decay series, where different Rn isotopes occur. Despite its low natural activity concentration in the environment, 222Rn (half life = 3.8 days) is an important radioactive noble gas because can generate the heavy metals 218Po, 214Pb, 214Bi and 214Po which can settle in the lungs, causing major diseases in the respiratory tract, including the induction of metastasis. Ten silicate rocks of variable composition and commercial use have been selected for evaluating the radon presence in human environments. They have been benefited by companies in Cachoeiro de Itapemirim (ES) and include magmatic (diorite, syenite, charnockite, monzogranite, granitic pegmatite) and metamorphic rocks. The study involved the acquisition of U, Th and K radiometric data, as well the monitoring of the 222Rn gas exhalation, coupled with petrographic and physical rock indices. The U and Th content range was 2.9-37 and 0.3-84 ppm, respectively, where the radioelements content was consistent with the presence or absence of accessory minerals hosting them. The amount of radon emanated from the rocks was directly related to the petrography of each material, especially the degree and types of microcracks and the contacts between minerals that are determinants of the rocks microporous net, thus, leading to a greater or lesser permeability, which in turn controls the exhalation. The comparison of the 222 Rn generated by the rock with the amount effectively exhaled indicated that the exhalation rate is negligible... (Complete abstract click electronic access below)

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2

Amaral, Paulo Giovany Quadros do. "Caracterização radiométrica e de exalação de Radônio em rochas ornamentais silicáticas beneficiadas no Estado do Espírito Santo /." Rio Claro : [s.n.], 2011. http://hdl.handle.net/11449/92886.

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Orientador: Tamar Milca Bortolozzo Galembeck
Coorientador: Daniel Marcos Bonotto
Banca: Antonio Carlos Artur
Banca: Fabiano Cabañas Navarro
Resumo: O trabalho realizou avaliações relativas ao comportamento radiométrico e de exalação do gás radônio em rochas ornamentais e de revestimento exploradas nos estados brasileiros de Minas Gerais e Espírito Santo. Sabendo que as rochas apresentam em sua constituição determinados teores de elementos radioativos tais como 87Rb, 40K, 238U, 235U e 232Th, sendo os três últimos a gerar em suas séries por decaimento o Rn e, apesar da baixa concentração natural do mesmo nos diversos ambientes e de sua curta meia vida de 3,8 dias, adquire importância pelo fato de seu decaimento gerar os elementos metálicos 218Po, 214Pb, 214Bi e 214Po que podem se fixarem nos pulmões causando patologias importantes nas vias respiratórias, especificamente na indução de metástases. Devido à importância de conhecer as concentrações do gás radônio nos ambientes de convívio humano foram escolhidas 10 rochas silicáticas de variedade geológica e de destaque comercial beneficiadas por empresas de Cachoeiro de Itapemirim - ES, compreendendo rochas magmáticas dadas por diorito, sienito, charnockito, monzogranito e três pegmatitos graníticos e por três rochas metamórficas. O estudo, envolvendo os dados radiométricos de U, Th, K e de monitoramento de exalação do gás 222Rn, revela uma boa correlação entre os parâmetros petrográficos e índices físicos das rochas. Os teores de U variaram de 2,9 ppm a 37 ppm e Th de 0,3 ppm a 84 ppm, mostrando que as concentrações destes radionuclídeos característicos para cada tipo de rocha, revelam a perfeita coerência entre a presença ou ausência de minerais acessórios detentores de elementos radioativos. A quantidade de exalação de radônio fornecida pelas rochas está diretamente relacionada aos aspectos petrográficos de cada material, principalmente ao grau e tipos de... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: This work carried out assessments on the radiometric behavior and exhalation of radon gas in dimensional and surfacing stones exploited in the Brazilian states of Minas Gerais (MG) and Espírito Santo (ES). The rocks usually contain different levels of the radionuclides 87Rb, 40K, 238U, 235U and 232Th, the last three forming radioactive decay series, where different Rn isotopes occur. Despite its low natural activity concentration in the environment, 222Rn (half life = 3.8 days) is an important radioactive noble gas because can generate the heavy metals 218Po, 214Pb, 214Bi and 214Po which can settle in the lungs, causing major diseases in the respiratory tract, including the induction of metastasis. Ten silicate rocks of variable composition and commercial use have been selected for evaluating the radon presence in human environments. They have been benefited by companies in Cachoeiro de Itapemirim (ES) and include magmatic (diorite, syenite, charnockite, monzogranite, granitic pegmatite) and metamorphic rocks. The study involved the acquisition of U, Th and K radiometric data, as well the monitoring of the 222Rn gas exhalation, coupled with petrographic and physical rock indices. The U and Th content range was 2.9-37 and 0.3-84 ppm, respectively, where the radioelements content was consistent with the presence or absence of accessory minerals hosting them. The amount of radon emanated from the rocks was directly related to the petrography of each material, especially the degree and types of microcracks and the contacts between minerals that are determinants of the rocks microporous net, thus, leading to a greater or lesser permeability, which in turn controls the exhalation. The comparison of the 222 Rn generated by the rock with the amount effectively exhaled indicated that the exhalation rate is negligible... (Complete abstract click electronic access below)
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Silva, Jesué Antonio da. "Caracterização geológica e tecnológica de unidades gnáissicas e graníticas do sudoeste de Mato Grosso para fins de exploração como rochas ornamentais e para revestimento /." Rio Claro : [s.n.], 2009. http://hdl.handle.net/11449/103001.

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Resumo: Os estudos geológicos, petrográficos, geoquímicos e tecnológicos (físicosmecânicos) e de alterabilidade de exposições de extensas áreas de rochas cristalinas no sudoeste do Estado do Mato Grosso, com objetivo da qualificação como rocha ornamental e de revestimento, possibilitou a oferta de novas variedades estéticas de rochas que apresentem a adequada identificação, tipificação e padronização das características tecnológicas. Visa-se ampliar a oferta deste bem mineral no estado, atualmente um dos menores produtores do pais, contribuindo assim para a implantação e desenvolvimento desta cadeia produtiva de transformação e no desenvolvimento sócio-econômico do Estado. As áreas propostas para o estudo localizam-se na região sudoeste do estado, que detém um dos maiores tratos geológicos relativamente conhecidos, além da sua posição geográfica favorecida pela malha viária, sendo descritos 10 tipos entre granitos, diabásios, gnaisses e anfibolitos agrupados nas cores vermelha, cinza e preta e que demonstram possibilidade econômica de lavra. Os resultados obtidos nos ensaios tecnológicos das variedades mostram que os parâmetros analisados situam-se dentro dos limites padrões estabelecidos pelas normas e obedecem satisfatoriamente os valores limítrofes fixados para granitos utilizados em revestimento em ambientes interiores e exteriores.
Abstract: The study of potentiality and qualification as a dimension stone and covering of granites and oriented rocks occurring in the south of the Mato Grosso State, Brazil, using geological, petrographical, technological and alterability characterization aims to increase the offer of new varieties of dimension stones in the state. It also aims to propitiate the economic transformation of this mineral resource adding new esthetic varieties in according to technological patterns and adequate identifying and typology. The research also contributes to the implantation and development of this productive chain to the social and economical development of the state. In the studied areas located at the south region of the Mato Grosso State fourteen rock types for dimension stones are recognized. They include granites, gabbros, gneisses and amphibolites grouped by the colors in red, grey and black types and showing economic potential of plowing. The results obtained in the technological essay show that the rock parameters are sited within the standard limits established by technical rules and obey satisfactorily the limit values fixed for granites in internal and external covering uses
Orientador: Antonio Misson Godoy
Coorientador: Amarildo Salinas Ruiz
Banca: Antônio Carlos Artur
Banca: Marcos Aurélio Faria de Oliveira
Banca: Antonio João Paes de Barros
Banca: Antenor Paraguassú
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Lima, Filipe Goulart. "Morro do Níquel : fragmento de manto exumado na Faixa Brasília Meridional /." Rio Claro, 2017. http://hdl.handle.net/11449/151669.

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Orientador: Antenor Zanardo
Coorientador: Gergely Andres Julio Szabó
Banca: Norberto Morales
Banca: Guillermo Rafael Beltran Navarro
Banca: Tiago da Rocha Karniol
Banca: Larissa Marques Barbosa de Araújo
Resumo: Este trabalho apresenta os resultados dos estudos petrogenéticos detalhados realizados nos serpentinitos que constituem do Morro do Níquel, maciço ultrabásico mineralizado em níquel laterítico, situado na Faixa Brasília Meridional, ao norte da Zona de Sutura de Alterosa, localizado no Município de Pratápolis (MG), sul/sudoeste do Estado de Minas Gerais, Brasil. Os serpentinitos possuem cor verde escuro a preto, aspecto maciço e é constituído por mais de 95% de lizardita/crisotilo, com ocorrências localizadas de antigorita. O padrão estrutural do maciço é compatível com aqueles gerados pela deformação de em um corpo rígido em matriz dúctil dentro de zona de cisalhamento. Os dados mineralógicos, petrográficos e geoquímicos, em associação com os de campo e de descrição de testemunho de sondagem rotativa, apontam que o protólito destas rochas seria um corpo dunítico de granulação média a grossa e textura granular, suas dimensões seriam superiores a 800 x 400 metros e com mais de 350 metros de espessura. Os dados obtidos indicam que o dunito é mantélico e possibilitou propor um modelo evolutivo desde a exumação do manto até a colocação sobre embasamento TTG e serpentinização. A exumação se inicia com o adelgaçamento da crosta continental durante a instalação de um sistema rifte, que teria evoluído ao ponto de atingir a "super extensão" da crosta e o desenvolvimento de uma crosta oceânica. Com o fechamento do oceano decorrente de colisão continental, no neoproterozóico, o corpo dunítico foi alojado sobre o embasamento cristalino, na margem passiva da placa que contém o Cráton São Francisco. A serpentinização do dunito ocorreu tardi-pós aloctonia, catalisada pela atuação do Cinturão de Cisalhamento do Campo do Meio, em condições de fácies visto verde, fácies prehnita-pumpelyíta, ... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: This work presents results from detailed petrogenetic studies performed on the Morro do Níquel (Nickel Hill) serpentinites, an ultrabasic massif mineralized in lateritic nickel, located in the Southern Brasília Belt, north of the Alterosa Suture Zone, Municipality of Pratápolis (MG), southwest of the State of Minas Gerais-Brazil. The serpentinite has a dark color, apparently massive aspect and consist of more than 95% lizardite / chrysotile, with localized occurrences of antigorite. The structural pattern of the massif is compatible with those generated by the shear of a rigid body in a ductile matrix within a shear zone. The mineralogical, petrographic and geochemical data, in association with the field and drill hole logs description, indicate that the protolith of these rocks would be a dunitic body of medium to large granulation and granular texture, with dimensions superior to 800 x 400 meters and with more than 350 meters of thickness. The obtained data indicate that the dunite is mantellic and it was possible to propose an evolutionary model from the exhumation of the mantle dunitc body to the emplacement on the TTG basement and serpentinization. The exhumation begins with the thinning of the continental crust during the installation of a rift system, evolving to allow the hyper-extension of the crust until the development of an oceanic crust. With the continental collision, in the Neoproterozoic, the dunite was hosted on the crystalline basement, in the passive margin of the plate that contains the San Francisco Craton. The dunite serpentinization occurred late-post aloctonia, catalyzed by the Campo do Meio Shear Belt, under conditions of green facies, prehnite-pumpelyite facies, with low fugacity of oxygen and sulfur and high H2 (aq.) activity
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Pazeto, Abiliane de Andrade [UNESP]. "Correlação entre propriedades petrográficas e comportamento tecnológico e de alterabilidade das rochas ornamentais silicáticas Diamante Negro (BA), Ocre Itabira e Banco Galaxy (ES)." Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/92883.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
O objetivo da presente pesquisa foi estabelecer a correlação entre as propriedades petrográficas e o comportamento tecnológico e de alterabilidade de três materiais utilizados como rochas ornamentais e para revestimento. Os tipos petrográficos correspondem a um microgabro (Diamante Negro), um hornblenda sienito pórfiro com quartzo (Ocre Itabira) e um granito pegmatóide com granada e sillimanita (Branco Galaxy), sendo o primeiro proveniente do estado da Bahia e os dois últimos do estado do Espírito Santo. Os materiais foram caracterizados petrograficamente e submetidos a uma bateria de ensaios físico-mecânicos e de alteração acelerada que compreenderam determinações de índices físicos, desgaste abrasivo Amsler, compressão uniaxial simples, resistência à flexão 3 e 4 pontos, impacto de corpo duro, velocidade de propagação de ondas ultrassônicas longitudinais, coeficiente de dilatação térmica linear e resistência ao ataque químico sob efeito de compostos agressivos e em câmaras saturadas em atmosfera salina e dióxido de enxofre (SO2). Os resultados demonstram que o comportamento tecnológico das rochas está intrinsecamente relacionado aos aspectos mineralógicos, estruturais e texturais inerentes a cada tipo petrográfico. O Diamante Negro é o material detentor dos maiores índices físico-mecânicos, uma vez que suas características petrográficas são marcadas por granulação fina, bom entrelaçamento mineral, e baixo grau de microfissuramento. Quanto à alteração acelerada, no entanto, apresentou variações cromáticas consideráveis, dado seu elevado teor de minerais máficos. O tipo comercial Ocre Itabira também apresentou boas propriedades tecnológicas, com valores inferiores ao Diamante Negro devido principalmente à sua granulação...
The objective of this research was correlating petrographical properties to the technological and alterability behavior of three materials used as ornamental and building stones. The samples correspond to a microgabbro (Diamante Negro), a hornblende porphiral syenite with quartz and (Ocre Itabira) a pegmatoid granite with garnet and sillimanite (Branco Galaxy), being the first sample originating from the Bahia state and the last one from Espírito Santo state. The materials were petrographically analyzed and submitted to physical mechanics tests and chemical alterability including measurements of physical indexes, abrasion resistance, compressive strength, modulus of rupture, flexural strength, impact strength, ultrasonic pulse velocity, linear thermal expansion coefficient and resistance to the chemical attack accomplished by aggressive compositions and chambers which simulate both sea-salt and sulphur dioxide weathering. The results reveal the influence of minerals, textural and structural features over the studied stones behavior during the performed tests. Diamante Negro is the material which showed the highest physical-mechanics properties, once their petrographical parameters correspond to fine grain size, good mineral interlacement, and low microcrack degree. However, relating to the chemical alterability it showed considerable chromatic deterioration, given its high content of mafic minerals. The commercial type Ocre Itabira also presented good technological properties, with inferior values than Diamante Negro due to its large grain size granulation and high degree of relative microcracking. The brownish coloration of potash feldspars porphyries present in its mineralogical composition turned the effects caused by the chemical reagents less evident. In general, Branco Galaxy presented the smallest values of... (Complete abstract click electronic access below)

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Silva, Jesué Antonio da [UNESP]. "Caracterização geológica e tecnológica de unidades gnáissicas e graníticas do sudoeste de Mato Grosso para fins de exploração como rochas ornamentais e para revestimento." Universidade Estadual Paulista (UNESP), 2009. http://hdl.handle.net/11449/103001.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Os estudos geológicos, petrográficos, geoquímicos e tecnológicos (físicosmecânicos) e de alterabilidade de exposições de extensas áreas de rochas cristalinas no sudoeste do Estado do Mato Grosso, com objetivo da qualificação como rocha ornamental e de revestimento, possibilitou a oferta de novas variedades estéticas de rochas que apresentem a adequada identificação, tipificação e padronização das características tecnológicas. Visa-se ampliar a oferta deste bem mineral no estado, atualmente um dos menores produtores do pais, contribuindo assim para a implantação e desenvolvimento desta cadeia produtiva de transformação e no desenvolvimento sócio-econômico do Estado. As áreas propostas para o estudo localizam-se na região sudoeste do estado, que detém um dos maiores tratos geológicos relativamente conhecidos, além da sua posição geográfica favorecida pela malha viária, sendo descritos 10 tipos entre granitos, diabásios, gnaisses e anfibolitos agrupados nas cores vermelha, cinza e preta e que demonstram possibilidade econômica de lavra. Os resultados obtidos nos ensaios tecnológicos das variedades mostram que os parâmetros analisados situam-se dentro dos limites padrões estabelecidos pelas normas e obedecem satisfatoriamente os valores limítrofes fixados para granitos utilizados em revestimento em ambientes interiores e exteriores.
The study of potentiality and qualification as a dimension stone and covering of granites and oriented rocks occurring in the south of the Mato Grosso State, Brazil, using geological, petrographical, technological and alterability characterization aims to increase the offer of new varieties of dimension stones in the state. It also aims to propitiate the economic transformation of this mineral resource adding new esthetic varieties in according to technological patterns and adequate identifying and typology. The research also contributes to the implantation and development of this productive chain to the social and economical development of the state. In the studied areas located at the south region of the Mato Grosso State fourteen rock types for dimension stones are recognized. They include granites, gabbros, gneisses and amphibolites grouped by the colors in red, grey and black types and showing economic potential of plowing. The results obtained in the technological essay show that the rock parameters are sited within the standard limits established by technical rules and obey satisfactorily the limit values fixed for granites in internal and external covering uses

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Janasi, Valdecir de Assis. "Geologia e petrologia do maciço monzodiorítico-monzonítico de Piracaia-SP." Universidade de São Paulo, 1986. http://www.teses.usp.br/teses/disponiveis/44/44135/tde-26092012-145409/.

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0 maciço de Piracaia aflora na parte N do Estado de São Paulo, ocupando área de 32 km2. É composto por uma suite de rochas em boa parte gnaissificadas e metamorfisadas, dominada por monzodioritos e monzonitos, mas com variações desde dioritos até álcali-quartzo sienitos e álcali granitos. A tendência composicional assim definida é semelhante à da série granitóide, \"alcalina\",(Lameyre & Bowden, 1982) . As rochas do maciço invadem a região de contato entre ortognaisses do Complexo Socorro e rochas supracrustais migmatizadas do Complexo Metamórfico Piracaia. São invadidas restritamente por veios granitóides; as relações de contato com corpos maiores de granitóides anatéticos vizinhos não são claras. A geração da foliação presente nas rochas do maciço é atribuída à fase de deformação \'F IND.n+2\'; dobras mega e mesoscópicas da fase \'F IND.n+3\' afetam essa foliação. Rochas monzodioríticas e monzoníticas formam a parte central do maciço, e são invadidas, nas bordas, pelos termos mais diferenciados, numa seqüência geral de colocação \"máfico-félsico\". A colocação dos facies tardios se processa sob um regime de esforços. As rochas ígneas preservadas no maciço têm como minerais principais plagioclásio, feldspato alcalino, biotita e augita. Fe-hiperstênio só aparece em alguns monzonitos, e quartzo, nas rochas mais diferenciadas. Como acessórios mais comuns, encontram-se apatita, magnetita e ilmenita. A cristalização dos feldspatos geralmente se inicia com o plagioclásio, mesmo em termos mais diferenciados, onde ele é mais sódico. Nas rochas monzodioríticas-monzonítìcas, após a coprecipitação de ambos os feldspatos, pode ser atingido um estágio de reabsorção do plagioclásio. Os máficos principais, e a sua seqüência de cristalização (biotita antes de augita, em especial nos monzodiorìtos) refletem a composição das rochas (principalmente, a riqueza em potássio), e o caráter pouco hidratado do sistema. A tendência, com a diferenciação, é de um aumento da razão Fe/ (Fe + Mg) em ambos os minerais, considerada compatível com a progressiva diminuição de f(H2O) e f(O2) no sistema. Em rochas monzodioríticas e monzoníticas, são comuns estruturas de segregação, como ocelos \"sieníticos\" e vênulas estictolíticas, em parte com migração posterior ao desenvolvimento de uma foliação. Os litotipos dos facies claros tardios do maciço são petrograficamente semelhantes às vênulas maiores, o se colocam, ao menos em parte, após o início dos processos de segregação. A geração inicial dos facies dioríticos a monzoníticos \"antigos\" parece devida cristalização fracionada , possivelmente governada pela extração de cristais em meio líquido. A gênese das estruturas posteriores de segregação (e dos facies \"tardios\") é admitida como resultado de processos de extração de líquidos residuais, ao que parece favorecidos pela deformação. A hipótese de que as segregações sejam reflexo de processos anatéticos pode justificar a distribuição dos elementos traços, e não pode ser descartada, mas parece menos viável, dada a similaridade da composição dos minerais aí presentes com a dos que cristalizaram nas rochas ígneas primárias do maciço, e as temperaturas relativamente elevadas requeridas para a fusão de protolitos de composição intermediária. As hipóteses genéticas foram testadas, de um modo semi-quantitativo, por modelagens geoquímicas. A extração de fases de cristalização precoce (plagioclásio, biotita e augita) responde de modo satisfatório pelas tendências químicas principais do maciço. Nos modelos de cristalização fracionada, o plagioclásio responde por mais de 50% da fase sólida extraída, e tem sua participação aumentada nos estágios tardios de diferenciação, onde o clinopiroxênio é fracionado em proporção menor; a biotita é geralmente o mineral máfico mais importante no fracionamento. 0 metamorfismo inicial no rnaciço é considerado \"sin-plutônico\", e contemporâneo à geração de segregações. Provoca reequilíbrios químicos , como adaptação a temperaturas menores (porém ainda elevadas) e fugacidades de H2O maiores . A contínua diminuição de T e o aporte de mais água provoca uma sucessão de peragêneses de grau metarnórfico mais baixo nas rochas do maciço, com a instabilizaçáo dos piroxênios e geração de hornblendas, que posteriormente dão lugar a paragêneses com biotita esverdeada e epidoto. 0 metamorfismo de grau mais baixo afeta as rochas de 75% do maciço, que paralelamente são as que têm aspecto gnáissico mais marcante. A distribuição espacial das rochas afetadas pelo meta morfismo indica que o aporte de fluidos foi facilitado na zona de borda do maciço, em especial a leste. Uma isócrona Rb-Sr em rocha total de 582±13 ma foi obtida em rochas metamorfisadas dos facies tardios do maciço, e é interpretada como a idade de rehomogeneização isotópica do sistema, que acompanha a recristalízação das rochas, contemporânea à fase de deformação \'F IND.n+ 2\'.
The Piracaia massif, located in the NE part of the State of São Paulo, crops out over 32 km2. Rock types cover a wide compositional range (diorites to alkali-feldspar quartz syenites and related granites), similar to the \"alkaline\" granitoid tendency of Lameyre & Bowden (1982), but monzodiorites and monzonites are by far predominant. Most rocks show, at least in part, tectonic foliation and metamorphic recrystallization. The massif was emplaced in the area of contact between the Socorro orthogneisses and migmatized supracrustal units of the Piracaia Metamorphic Complex. Locally, late granitoid veins intruded the massif with, but the contact and structural relations of the massif with nearby anatectic granites are unknown. Foliation within the massif is attributed to the regional \'F IND.n+2\' phase of deformation. Monzodiorites and monzonites, which comprise the central part of the massif, were intruded along their borders by late differentiated facies, apparently under forceful conditions. The intrusion sequence proceeded from more mafic to more felsic rock types. The principal primary minerals observed in preserved igneous textures are plagioclase, alkali feldspar, biotite and augite; Fe-hypersthene is found in some monzonites, and quartz in late differentiates. Main accessory minerals are apatite, magnetite and ilmenite. Crystallization usually began with plagioclase and biotite, followed by augite and alkali feldspar, this last mineral usually observed as an interstitial phase. Resorption of plagioclase was probably important in many monzonites and monzodiorites, alkali feldspar occasionally being seen as mantles around this mineral. The presence of augite and biotite in these rocks is a result of high K activity in the magmas, coupled with a relatively low H2O content. The chemical tendency, towards an increased Fe/ (Fe + Mg) ratio with differentiation in both minerals, is compatible with crystallization under diminishing fH2O and fO2. Syenitic ocellar and styctolithic \"segregation\" structures, in part later than the development of a foliation, occur pervasively in many monzodiorites and monzonites. Larger felsic veins are also found, in part later than the earliest segregations. The earliest rock types (diorites to leuco-monzonites) show petrographic and chemical relations compatible with derivation by crystal fractionation, possibly controlled by crystal extraction from a predominantly liquid mush. Late rock types, such as small segregations and larger masses of felsic differentiates, may represent residual liquids extracted from largely crystalline mushes. Thus, normal differentiation processes are possibly responsible for the generation of both early (predominant) rocks as well as late, more felsic varieties. On the other hand, an hypothesis of partial melting of and already crystallized intermediate rock mass (early monzodiorites and monzonites), coupled with segregation, is at least compatible with the distribution pattern of some trace elements in the late felsic facies. Crystallization processes are nevertheless favoured, since the compositions of minerals in segregations are very similar to those found in early rock types, and the temperature requirements for melting of intermediate, relatively dry protoliths seem to be unreasonably high. Petrogenetic hypotheses were tested using subtraction and trace-element diagrams. The separation of early-crystallizing minerals (plagioclase, biotite and augite) could reproduce differentiation paths like those shown by the Piracaia rocks. Up to 50% plagioclase would have to be fractionated in the early stages, and even more later; biotite and, to a lesser extent, augite, would have to be separated in significant amounts to account for major and trace element trends. Initial metamorphism within the massif is considered \"syn-plutonic\", related to the beginning of segregation; primary felsic and mafic minerals recrystallized in response to diminishing (but still high) temperatures and an increase in fH2O. Later metamorphism at diminishing temperatures generated hornblende (mainly from pyroxenes), and this, in turn, is replaced by lower-grade assemblages, mainly greenish biotite and epidote. Up to 15% of the massif shows both low-grade mineralogy and tectonic gneissic foliation; H2O influx, which favoured both deformation and recrystallization, was probably most significant along the marginal parts of the massif. A Rb-Sr whole-rock reference isochrone of 582 ± 13 Ma was obtained for the metamorphosed late facies. This value is interpreted as a metamorphic homogenization age, more or less contemporaneous with the \'F IND.n+2\' regional phase of deformation.

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Lima, Maria Angélica Batista. "Estudo do comportamento dos gnaisses Casablanca, Juparaná Delicato e Giallo Falésia (Ceará - Brasil) em atmosfera salina /." Rio Claro : [s.n.], 2006. http://hdl.handle.net/11449/102989.

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Resumo: Nesta pesquisa procurou-se simular as condições de atmosfera quimicamente agressiva (atmosfera marinha) por meio da exposição dos gnaisses Casablanca, Juparaná Delicato e Giallo Falésia em duas distintas câmaras climáticas de névoa salina, que permitiram a realização de ensaios do tipo contínuo e cíclico. Os ensaios tecnológicos de controle e as análises realizadas visaram à compreensão e interpretação das alterações observadas ao final dos respectivos tempos de exposição. Para escolha das propriedades tecnológicas avaliadas foram considerados os graus de influência e/ou de dependências no processo de alteração das rochas, bem como o espaço físico da câmara que delimitou as dimensões das amostras que foram expostas e o número de corpos-de-prova que foi ensaiado. No ensaio contínuo foi utilizada a câmara Modelo Bass USC com a temperatura mantida em (35±2)°C, a pressão de ar comprimido em 70 KPa e a solução de ensaio a 5% de NaCl com pH entre 6,5 e 7,2. O acervo exposto nesta câmara salina compreendeu então 73 (setenta e três) corpos-de-prova representando os três gnaisses que foram retirados ao final de 360, 720 e 1080 horas de exposição para realização de ensaios tecnológicos de controle, com a finalidade de monitorar qualitativamente as alterações ocorridas durante os respectivos períodos de exposições. No ensaio cíclico foi utilizada a câmara Modelo BASS MP-GS-01/2004, tendo sido composto por 30 ciclos onde foram alternadas 6 horas de névoa salina com 12 horas de secagem para cada ciclo concluído. Para este ensaio a temperatura foi mantida em (40±5)°C, a pressão de ar comprimido em 70 KPa e a solução de ensaio a 10% de NaCl com pH entre 6,5 e 7,2. O acervo exposto compreendeu 18 (dezoito) corpos-de-prova na forma de cubos com 5cm de arestas, representando os gnaisses Casablanca, Delicato e Falésia... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: In this research, aggressive atmosphere conditions (marine atmosphere) were simulated using three commercial rock types (Casablanca, Delicato and Falésia). The gneisses were located in two different saline mist weathering chambers that operating in continuous and cyclical tests process type. The technological tests for control and analyses allowed the understanding and interpretation of the observed weathering processes after respective time of exposition of the stone. The choice of technological properties was guided by the influence and/or dependence degree of weathering processes with the saline chamber dimensions (influence on size and number of samples). The continuous test method have used a chamber Model Bass USC with the temperature kept in (35±2)°C, the air pressure compressed in 70 KPa and the saline solution (5% of NaCl) with pH values between 6.5 and 7.2. In that test, the gneisses were represented by 73 (seventy three) samples in the chambers that had been removed at the end of 360, 720 and 1080 hours of exposition hours to the control technological tests, in order to monitoring alterations occurred during the respective exposition. The cyclical test have used chamber Model BASS MP-GS- 01/2004. For this test, the samples passed by 30 cycles alternated with saline mist for 6 hours and 12 hours of drying for each concluded cycle. The temperature was kept in (40±5) °C, the air pressure compressed in 70 KPa and the saline solution (10% of NaCl) with pH between 6.5 and 7.2. In that test the gneisses were represented by 18 (eighteen) 5 cm cubic samples in the chambers. These samples had been removed after completing 15 cycles, for visual inspection and photographic register. After 30 cycles, the samples have been weighed in analytical scale and evaluated alterations during the respective exposition period. The two chosen ways (continuous and cyclic accelerated tests) allow... (Complete abstract click electronic access below)
Orientador: Antonio Carlos Artur
Coorientador: José de Araújo Nogueira Neto
Banca: Antônio Gilberto Costa
Banca: Francisco Wilson Hollanda Vidal
Banca: Tamar Bortolozzo Galembeck
Banca: Maria Heloísa Barros de Oliveira Frascá
Doutor

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Leme, Thaís Guitzlaf. "Geotermobarometria das rochas do Grupo Araxá e do Complexo Guaxupé na região de Guaxupé - Nova Resende, MG /." Rio Claro, 2019. http://hdl.handle.net/11449/180465.

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Orientador: Guillermo Rafael Beltran Navarro
Banca: Antenor Zanardo
Banca: Filipe Gourlat Lima
Resumo: A área de estudo situa-se no sul da Faixa Brasília Meridional, no sudoeste do estado de Minas Gerais e compreende uma faixa entre os municípios de Guaxupé, Monte Belo, Nova Resende e São Pedro da União, no contato entre as unidades que compõem o Complexo Guaxupé e litotipos atribuídos ao Grupo Araxá. Esta região situa-se em uma zona de blocos crustais amalgamados durante a orogênese brasiliana no Neoproterozoico e marca o limite entre terrenos granulíticos (Complexo Guaxupé) e litotipos adjacentes envolvidos no processo colisional e pós colisional (Grupo Araxá). Este contato é delimitado pela Zona de Cisalhamento Varginha, que representa uma quebra nas condições metamórficas entre as unidades. Neste trabalho são apresentados dados petrográficos, de química mineral e geotermobarométricos (média P-T calculada pelo software THERMOCALC, software RCLC e geotermômetros Zr-em-rutilo e Ti-em-quartzo) com o objetivo de investigar e determinar as condições de pressão e temperatura dos litotipos que ocorrem no contato entre o Complexo Guaxupé e o Grupo Araxá nessa região. Na área de estudo, o Complexo Guaxupé é constituído principalmente por rochas ortoderivadas de natureza básica a ácida, com predomínio de composições intermediárias, representadas por granulitos (ortopiroxênio gnaisses) félsicos a máficos, com intercalações de anfibólio e/ou biotita gnaisses (sem ortopiroxênio), além de intercalações de metassedimentos com sillimanita, granada, ortoclásio e rutilo. O Grupo Araxá é cons... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The study area is located at the south of Southwerst Brasília Belt, southeast of Minas Gerais, and it comprehends a strip among the cities of Guaxupé, Monte Belo, Nova Resende and São Pedro da União, in contact with unities that compose the Guaxupé Complex and lithotypes attributed to the Araxá Group. This region is in a zone with crustal blocks amalgamated during the Brazilian orogenesis in Neoproterozoic, and it determines the limit between granulitic terrains (Guaxupé Complex) and adjacent lithotypes involved in collisional and post-collisional processes (Araxá Group). The contact is delimitated by the Varginha Shear Zone, which represents a disruption of metamorphic conditions amid the unities. This paper presents petrographic, mineral chemistry and geothermobarometric data (average P-T calculated by the THERMOCALC software, software RCLC and geothermometers Zr-in-rutile and Ti-in-quartz) in order to investigate and determine the pressure and temperature conditions of the lithotypes that occur in the contact between the Guaxupé Complex and Araxá Group. In the study area, the Guaxupé Complex consists especially ortho-derivative rocks of basic to acidic nature, represented by felsic to mafic granulites (orthopyroxene gneisses), and amphibole and/or biotite gneisses intercalations (orthopyroxene free), as well as metasediments intercalations with sillimanite, garnet, orthoclase and rutile. The Araxá Group consists of pelitic to psamo-pelites metasediments with orthogneisses,... (Complete abstract click electronic access below)
Mestre

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Torró, i. Abat Lisard. "The shift from subduction-initiation to true subduction in intra-oceanic systems: tectonic, magmatic and metallogenic evolution of Early Cretaceous arc-related units of Central and Oriental cordilleras in the Dominican Republic." Doctoral thesis, Universitat de Barcelona, 2017. http://hdl.handle.net/10803/401648.

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The Maimón and Los Ranchos formations in Central and Oriental Cordilleras, Dominican Republic, Hispaniola Island, are acknowledged to be representative of the most primitive tholeiitic magmatic series recorded in the Greater Antilles of the Caribbean. Besides their importance for the study of the early tectonic and magmatic evolution of the Caribbean island-arc, these formations are renowned for hosting the Cerro de Maimón VMS and the world-class Pueblo Viejo epithermal deposits, currently under production, and a series of smaller metallic deposits and occurrences. Therefore, the integrated study of the hosting volcanic suites, the hydrothermal alterations and the sulfide mineralization from petrographic, geochemical and geochronological perspectives stands out as an excellent opportunity to understand the metallogenic evolution associated to the early evolution of intra-oceanic subduction systems. In this Thesis, new whole rock major- and trace-element and radiogenic isotope data, detailed petrographic studies of the hosts, hydrothermal alterations and the sulfide mineralization and geochronological constraints by means of zircon U-Pb and molybdenite Re-Os dating are presented and discussed. Bottom to top, basalts and basaltic andesites of the Maimón Formation (metamorphosed in the greenschists-blueschists facies transition) and of the lower portion of the Los Ranchos Formation shift from LREE-depleted low-Ti tholeiites and boninites to LREE-richer (normal) low-Ti tholeiites. In addition, basaltic andesites, diorites, monzodiorites and andesites of the upper portion of the Los Ranchos Formation present island-arc tholeiitic and calc-alkaline affinities. These variations mirror the geochemical evolution from proto- to first-arc lavas documented in subduction-initiation ophiolites. The extrusion of the Maimón Formation volcanic rocks is here contextualized in the forearc segment, close to the subducting proto- Caribbean spreading ridge, in a hot-subduction scenario. On the other hand, the extrusion of the Los Ranchos Formation volcanic rocks is contextualized in the forearc-apical arc segment, and their volcanic and volcanosedimentary deposits evidence the progression from submarine to subaerial conditions of deposition. Plagiotonalite batholiths, plagiorhyolite stocks and plagiorhyolites from the Maimón and Los Ranchos formations have tholeiitic and M-type affinities. Volcanogenic massive sulfide (VMS) mineralization hosted in the Maimón Formation and the lower basaltic unit of the Los Ranchos Formation took place during the subduction-initiation stage of the Caribbean island-arc. Subsequently, porphyry Cu-(Mo) - high sulfidation epithermal mineralization took over in the Los Ranchos Formation at ca. 112 Ma, likely connected to a spread episode of acid magmatism during the steady-state or true- subduction regime.
Las formaciones Maimón y Los Ranchos en las Cordilleras Central y Oriental, República Dominicana, Isla la Española, son representativas de la serie toleítica más primitiva en las Grandes Antillas del Caribe. Más allá de su importancia para el estudio de la evolución magmática temprana del arco-isla caribeño, estas formaciones son también reconocidas por alojar el depósito VMS de Cerro de Maimón y el depósito epitermal de clase mundial de Pueblo Viejo, ambos en producción en la actualidad, así como de una serie de depósitos y mineralizaciones de menor tamaño. Por consiguiente, el estudio integrado de las series volcánicas encajantes, de las alteraciones hidrotermales y de las mineralizaciones de sulfuros desde un punto de vista petrográfico, geoquímico y geocronológico representa una excelente oportunidad para entender la evolución metalogenética durante la evolución temprana de sistemas subductivos en contextos intraoceánicos. En esta Tesis, nuevos datos de geoquímica de roca total (elementos mayores y traza e isótopos radiogénicos), estudios petrográficos de detalle del encajante, de las alteraciones hidrotermales y de las mineralizaciones de sulfuros, y datos sobre su geocronología por medio de edades U-Pb en zircón y Re-Os en molibdenita, son presentados y discutidos. De muro a techo, los basaltos de la Formación Maimón (metamorfizadas en facies transicionales de esquistos verdes-esquistos azules) y de la sección basal de la Formación Los Ranchos progresan desde basaltos toleíticos empobrecidos en Ti y LREE a boninitas y a basaltos toleíticos empobrecidos en Ti normales. La sección superior de la Formación Los Ranchos, además, aloja andesitas basálticas, dioritas, monzodioritas y andesitas con afinidades toleíticas transicionales a calcoalcalinas y calcoalcalinas. Estas variaciones a lo largo de la secuencia estratigráfica equivalen a las documentadas en basaltos de arco en ofiolitas de inicio de subducción. La extrusión de las rocas volcánicas de la Formación Maimón es contextualizada en el ante-arco, cerca de la zona de subducción de la dorsal proto- caribeña y en un escenario de subducción caliente. En cambio, las rocas ígneas de Los Ranchos se emplazaron en la zona de ante-arco y axial de arco, y las litofacies observadas en sus depósitos volcánicos y volcanosedimentarios indican la progresión desde una depositación en contextos submarinos a una en contextos sub-aéreos. Los batolitos plagiotonalíticos, los stocks plagioriolíticos y las plagioriolitas de ambas formaciones presentan afinidades toleíticas y signaturas tipo M. Las mineralizaciones VMS alojadas en la Formación Maimón y en la secuencia basal de Los Ranchos se formaron durante un régimen de inicio de subducción. En cambio, las mineralizaciones tipo pórfido Cu(Mo) – epitermales de alta sulfuración encajados en la secuencia superior de Los Ranchos se formaron aprox. a 112 Ma, previsiblemente conectadas genéticamente a intrusivos ácidos, durante un régimen de subducción verdadera.

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Xu, Jingyao. "Optimization of the use of diamond indicator minerals in diamond exploration in kimberlites." Doctoral thesis, Universitat de Barcelona, 2019. http://hdl.handle.net/10803/668786.

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Ti-rich minerals occur in xenoliths of metasomatized mantle peridotites, MARID and PIC. Xenocrysts produced by disaggregation during the intrusion have equivalent compositions. Early crystallization in the first intrusive stage in kimberlites and related rocks produces olivine phenocrysts that may have trapped inclusions of co-crystallizing rutile, Mg-rich ilmenite to geikielite and chromite. Geikielite may replace Ti-bearing minerals of the xenocrystic suite, producing a suite of magnesian ilmenites of intermediate compositions that follow an Mg enrichment trend depending on the grade of interaction xenocrysts/magma. Phlogopite microphenocrysts can start to crystallize in this stage. A second magmatic stage produces saturation in pyrophanite, that can precipitate or react with all the above Ti-rich minerals, producing crystallization of a suite of intermediate manganoan ilmenites whose compositions depend on that of the replaced Ti-mineral and the grade of interaction of the magma with the above crystals. Lately in this stage, qandilite-ulvöspinel-magnetite start to crystallize, together with perovskite, along with phlogopite microphenocrysts. Finally, the crystallization of ulvöspinel-magnetite crystals may be produced in disequilibria, inducing the development of atoll textures. Groundmass phlogopite crystallize in the late magmagtic stage. Monticellite can be formed in this stage. Interstitial glass can be produced at the end of this stage. Subsolidus hydrothermal processes are widespread in most of the kimberlites, with replacement of the early minerals by hydrous and carbonic fluids of kimberlitic provenance. Olivines and glass are replaced by serpentines and carbonates. A sequence of ilmenites (geikielite followed by pyrophanite) can precipitate directly or replace the above Ti-bearing minerals. Spinels and perovskites may also be replaced by Ti hydrogarnets and late perovskite or kassite accompanied by aeschynite. The composition of the replacing ilmenite depends on that of the replaced mineral. Hence, these ilmenites can retain Nb, Cr, Zr when replacing rutile or perovskite, chromite or crichtonite. Therefore, the trace composition of ilmenite cannot be used to extract petrogenetic information. Mg- or Mn-ilmenites cannot be used as DIM because they are very late minerals formed during the intrusion. When plotting the composition of these minerals in the existing IUGS classification diagrams there is an extensive overlap among kimberlites and related rocks. Thus the existing classification diagrams are not useful and we propose some amendments to the existing classification.

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Rice-Birchall, B. "Petrology and geochemistry of basic volcanics." Thesis, Keele University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314570.

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Gamil, Ali Saif. "Petrology and geochemistry of Shetland granites." Thesis, University of Liverpool, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316890.

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This study is concerned with the distribution, age, chemistry and geotectonic setting of the 21 granites in Shetland. The granites range in size from a few metres to 8 Km across and in age from Pre-Moine to early Carboniferous. The granites occupy a unique position in being placed approximately half way between Scotland and Norway Caledonides and about 320 Km east of southeast coast of Greenland, if Greenland is restored to its pre-continental Drift position as predicted by the best fit of Greenland and Europe. The Shetland granites have been subdivided into 5 groups according to their location to the east or west of Walls Boundary Fault ( a continuation of Great Glen Fault), mineralogical content and their occurrence in situ as granitic pebbles, as follows; Granites to the east of WBF include (1) hornblende-bearing granites (2) hornblende-free granites and (3) Granitic pebbles a) the Rova Head conglomerate & b) the Funzie conglomerate. Granites to the west of WBF include (4) Ronas Hill granite and its satellites and (5) Sandsting & Bixter granites which are grouped together because of their proximity and because the Bixter granite seems to be the acidic end product of the Sandsting granitoid. A detailed petrological and geochemical study has been made of each group. Samples from each occurrence have been examined for mineralogical content and analysed by a variety of methods for major and trace elements (XRF, INAA, RNAA). This infonnation has been used to derive the mechanisms which may have been responsible for the observed differentiation trends. To the east of the Walls Boundary Fault (WBF) are hornblende-bearing granites, hornblende-free granites and Funzie and Rova Head granitic pebbles. The hornblende-bearing granites are truncated by the WBF and characterized by high Sr and Ba values. The Spiggie granite within this hornblende-bearing group also contains considerable amounts of primary epidote. The hornblende-free granites are a miscellaneous group of granitic rocks ranging between two-mica granites and garnet bearing granites, albite keratophyre and trondhjemite dykes. To the west of WBF are Ronas Hill granophyre and its satellites (with drusy cavities containing crystals of stilpnomelane, quartz and epidote), Sandsting complex and Bixter granites. Major element modelling suggests that a plagioclase, biotite and hornblende fractionation process is appropriate for hornblende-bearing granites and Sandsting granite. Graphical and trace element modelling do not conflict with this too, but rare earth element modelling requires extraction of a quartz-feldspar phase. The classification of Shetland granitoids on the basis of ages and petrology has not been previously attempted. According to the Read classification, the Caledonian hornblende-free granites could be classified as Pretectonic and Syntectonic intrusions equivalent to his older granites. In contrast to the hornblende-bearing granites to the east ofWBF (Graven, Brae complexes and the Spiggie granite), the Graven and Brae appear to belong to the Appinite Suite while the Spiggie granite seems to be a forceful Newer Granite. According to Read the forceful Newer Granites were emplaced just after the Appinite Suite but in Shetland the Graven and Spiggie granites appear to be the same age (400 Ma). The Ronas Hill granite and its satellites, Sandsting and Bixter granites to the west of WBF are Upper Devonian granites and equivalent to the permitted last intrusions of Read, but do not appear to be of the caulderon or ring complex type typical of those in Scotland In terms of ages the hornblende-bearing granites have given K-Ar ages of about 400-430 Ma. The Ronas Hill granite and its satellites, Sandsting complex and Bixter granite give K-Ar ages about 360 Ma. Consideration of typology indicates that the hornblende-bearing granites, Ronas Hill & its satellites, the Sandsting complex and Bixter granite are I-Caledonian type whereas some of the hornblende-free granites are close to S-type. On the De La Roche classification system the Shetland granites are high-K calc-alkaline (except trondhjemite dykes and keratophyre in the hornblende-free granites group) and mostly plotted in the shoshonitic trend The geochemical comparison of the the post Devonian Ronas Hill granite and its satellites on the one hand and the closely associated late Devonian Shetland volcanics on the other, reveals that there is no link between them. A comparison of the Shetland and Scottish granitoids in terms of major, trace and rare earth elements reveals very close similarities between these two Caledonian regions. Both show the same high K-calc-alkaline (peccerillo & Taylor, 1976), the high alumina and alkali (Kuno, 1966) character, also show a general alkali-calcic character (Peacock, 1930) and they also have very good correlation in terms of some trace element variation diagrams such as Sr and Ba

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Lagergren, Hanna. "Magmatic Stoping and a Case Study from the Åva Ring Complex, Finland." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-183409.

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Magmatic stoping is a term that has been controversial almost since it was first mentioned over a century ago. Scientists have been arguing whether it plays an important part as an emplacement process of magma chambers, or whether it takes place at all. With growing evidence for both pro- and counterar guments the debate becomes tenser and the question raised is whether it is possible to find a unanimous answer. Magmatic stoping is often associated with the presence of xenoliths, “foreign” rocks that have been enclosed by magma. As parts of the roof or walls in the magma chamber detach, the pieces become trapped in it if they don’t have time to dissolve before the magma cools. The new cavities make room for a growing chamber and the possibility for magmatic stoping to be a volumetrically significant process is as well in discussion. The problematic starts early, beginning with the definitions of words like stoping, xenoliths, and rafts which are not unified. Natural findings of xenoliths in plutons are rare and speak against stoping but are often explained by xenoliths that possibly sunk down to the floor of magma chambers and become inaccessible for researchers. Nowadays there are several explanations to these statements that will be both presented and discussed in this thesis. A case study is also made from the Åva ring complex in Finland, and it has been shown to provide a fairly clear idea of the evidence for magmatic stoping. With remote sensing xenoliths have been mapped and measured and the results show that magmatic stoping is an abundant process and not something to be dismissed.

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15

Pagotti, Mariana Savietto. "Análise petrográfica da Formação Marília no município de Quintana-SP /." Rio Claro, 2016. http://hdl.handle.net/11449/180218.

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Orientador: Maria Rita Caetano-Chang
Banca: Paulo Milton Barbosa Landim
Banca: Emilio Carlos Prandi
Resumo: O Sistema Aquífero Bauru estende-se por cerca de 40% do estado de São Paulo, sendo umas das principais fontes de exploração de água subterrânea do estado; abastece integralmente 32,5% de seus municípios, abrangendo a maior parte do Planalto Ocidental Paulista. Nesse sistema destaca-se o Aquífero Marília, dado tratar-se de aquífero raso cuja explotação é menos onerosa. O presente estudo teve como objetivo a caracterização petrográfica dos arenitos da Formação Marília no município de Quintana, São Paulo, a fim de identificar possíveis minerais portadores de bário em sua estrutura, uma vez que estudos realizados em águas do Sistema Aquífero Bauru identificaram a presença desse elemento acima dos limites de potabilidade estipulados pela CETESB. Para a caracterização petrográfica foram analisadas lâminas delgadas em microscópio óptico, por difratometria de raio-X e microscopia eletrônica de varredura. Os arenitos são classificados como subarcóseos, de acordo com a classificação de Folk, sendo constituídos principalmente por quartzo e feldspato e, em menor quantidade, por fragmentos líticos e minerais acessórios. Os principais tipos de cimento observados são carbonatos, óxidos-hidróxidos de ferro e argilominerais. Por meio da microscopia eletrônica de varredura, identificou-se a presença de bário no cimento carbonático, o que suporta a ocorrência desse elemento nas águas do Aquífero Marília
Abstract: The Bauru Aquifer System covers approximately 40% of São Paulo State and it is one of the major sources of groundwater in the state, responsible for water supply to 32.5% of its municipalities, extending over most of the São Paulo Western Plateau. The present research focused on the petrographic characterization of Marília Formation sandstones, in the city of Quintana, São Paulo, in order to identify potential minerals containing barium in its structure, since previous studies of Bauru Aquifer System waters have reported the presence of barium exceeding the potability limit of CETESB. Petrographic analyses were executed using optical microscopy, Xray diffraction and scanning electron microscopy. The sandstones are classified as subarkose according to Folk classification and are mainly composed of quartz and feldspar; in minor amounts are composed of lithic fragments and accessory minerals. The main types of cement observed are carbonates, iron oxides and clays. Under scanning electron microscope it was identified the presence of barium in the carbonate cement, which support its occurrence in the waters of the Marília Aquifer
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16

Ipekgil, Ceren. "Geology And Petrology Of Beypazari-oymaagac Granitoids." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/2/12605846/index.pdf.

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The purpose of this study is to investigate the origin, source characteristics, evolution petrogenesis and emplacement mechanisms of Beypazari-Oymaagaç
granitoids. These granitoids are intruded into a metamorphic basement and nonconformably overlain by Neogene clastic rocks. Field work, petrographical and geochemical studies are carried out to determine the petrologic features and tectonic setting of the granitoid body. The Beypazari-Oymaagaç
pluton is a composite pluton with its host batholith, enclaves, aplite dykes and a pegmatite. The batholith is generally composed of quartz, K-feldspar, plagioclase and hornblende. Field observations and petrographic investigations indicate that the host batholith has granodiorite composition and shows distinct differences in the abundances of quartz, amphibole minerals (e.g., hornblende) and of enclaves. The samples taken from TavuktaSi Tepe contain relatively less amphibole and enclaves but more quartz. Compared with them, samples from the rest of the batholith have relatively abundant amphibole, K-feldspar megacrysts, and enclaves but less quartz. Enclaves derived from magma mixing/mingling processes are dioritic in composition. Geochemical data obtained from whole rock analyses show that the pluton is shallowly emplaced and has calc-alkaline, metaluminous to peraluminous chemistry. It is characterized by enrichments in LIL and LREE, especially in K, Rb and Th. Although, there is a distinct petrographic variation in the batholith, the geochemical characteristics are uniform throughout the pluton. The Oymaagaç
Granitoids which have I-type identity are typical representatives of magmatic arc environment. The present study suggests that the possible source of magma is the upper crust and can be compared with the coeval volcanism in Galatean Volcanic Arc.

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17

Birch, Graham John. "Petrology of the Madziwa Mafic Intrusion, Zimbabwe." Thesis, Imperial College London, 1985. http://hdl.handle.net/10044/1/37640.

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18

Solupker, Utku. "Petrology of Kula Volcanic Province, Western Turkey." Cincinnati, Ohio : University of Cincinnati, 2007. http://www.ohiolink.edu/etd/view.cgi?ucin1187013478.

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Thesis (Ph. D. )--University of Cincinnati, 2007.
Keywords: alkaline rocks; oxygen fugacity; dP/dT; polybaric fractionation; fractional melting Advisor: Dr. Attila I. Kilinc Title from electronic thesis title page (Nov. 17, 2007). Includes abstract. Includes bibliographical references.

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Al-Hafdh, Nabeel Mustafa Suliman. "The alteration petrology of the Cheviot granite." Thesis, University of Newcastle Upon Tyne, 1985. http://hdl.handle.net/10443/1866.

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The Cheviot Granite complex is a high-level pluton made up of six intrusive phases intruded into a pile of andesites of very similar composition to the bulk of the plutonics. The whole represents the eroded remnant of a lower Devonian volcano, erupted immediately after the continental collision that destroyed the Iapetus Ocean. The igneous history comprises two igneous cycles, both starting with basic granodiorite and including a late porphyritic ring dyke. The two cycles can be distinguished geochemically using Zr and K contents. Fractionation during each cycle involved precipitation of a biotite diorite cumulate. The second cycle ends with a highly evolved leucocratic microgranite. The geochemistry shows a rather shoshonitic - chemistry to the series, and trace elements are consistent with an immediately post-collisional origin. Hydrothermal alteration occurs in two phases, one associated in space and time with the porphyritic granodiorite of the first igneous cycle, and the other with that of the s~cond cycle. In both systems both potassic and sericitic alteration assemblages are found, and there is a wide development of propylitic alteration around these higher temperature zones. The two hydrothermal phases can be distinguished by the abundance of tourmaline in sericitic and propylitic rocks of the second cycle, and the abundance of calcium (mostly as calcite) in the sericitic rocks of the first phase. Geochemical flux calculations show that silica has been widely introduced to the granite during the alteration (in amounts up to 10\) and Ca and Sr removed. Other element fluxes are more complex, and may be coupled together. Comparison with other granites of N England and S Scotland shows that the Loch Doon complex and the Shap granite are very similar to Cheviot, that the Criffell Dalbeattie granite has a very similar early phase but diverges later, and that the Skiddaw, Weardale and Cairnsmore of Fleet granites are very different from Cheviot, being essentially granitic rather than granodioritic.

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20

Ghani, Azman Abdul. "Petrology and geochemistry of Donegal granites Ireland." Thesis, University of Liverpool, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243112.

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21

Viljoen, K. S. "Petrology of the Sutherland Commonage melilitite intrusives." Master's thesis, University of Cape Town, 1988. http://hdl.handle.net/11427/22496.

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The petrology of the Sutherland Commonage olivine melilitite intrusives have been investigated using petrographic and chemical methods. The occurrence consists of a ring dyke which surrounds a centrally located sill complex. The rock of the ring dyke is a typical melilitite which consists of olivine in a groundmass of melilite, clinopyroxene, opaque spinel, nepheline and perovskite. The sill complex is a multiple intrusion and is comprised of a lower green melilitite and an overlying (and younger) grey melilitite. The green melilitite is deuterically altered and the original mineralogy is destroyed to a large extent. The grey melilitite contains autoliths of the green and is a fairly typical monticellitic melilitite in which phenocrysts of olivine are set in a groundmass of melilite, monticellite, opaque spine!, nepheline and perovskite. Microprobe analyses of clinopyroxenes indicate that they are aluminous titanian diopsides and salites which exhibit complex zonation patterns. They record magmatic conditions ranging from the intrusive stage to a final phase of magmatic evolution during which a vapour phase evolved after the majority of the groundmass minerals had crystallised. The chemistry of olivine phenocrysts suggests that the parent magma to the Commonage intrusives accumulated in a temperature-zoned reservoir at the base of the lithosphere. Large, unzoned olivine phenocrysts crystallised in this chamber. Subsequent rupture of the chamber and ascent of magma led to supercooling and the crystallisation of abundant, strongly zoned phenocrysts of smaller size. Olivine crystallisation continued until the magma reached crustal levels. It is inferred from the chemistry of chromites and magnetites that the magma in the ring dyke was more evolved than those in the sill complex and that very oxidising conditions prevailed in the grey melilitite during the crystallisation of magnetite in this intrusive type. The high fO₂ may have resulted from the degassing of CO₂ after intrusion. Major and trace elements have been analysed for in eleven whole rock samples and the ⁸⁷Sr/⁸⁶Sr ratio was determined for seven of the same samples. The results of the geochemical study suggest that the Commonage melilitites were derived by the melting of a recently metasomatised region of the asthenosphere, probably under the influence of an ocean-island-type hotspot situated in the lower mantle.

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22

Sölpüker, Utku. "Petrology of Kula Volcanic Province, Western Turkey." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1187013478.

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23

Camargo, Jefferson Luiz [UNESP]. "Influência das propriedades petrográficas na qualidade do polimento de rochas ornamentais." Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/92856.

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O polimento de rochas ornamentais em escala industrial é realizado em equipamentos denominados politrizes, podendo estes serem semi-automáticos ou automáticos. O polimento é realizado pelo atrito gerado no movimento rotacional de elementos abrasivos dispostos em cabeçotes, denominados satélites, sob pressão, contra a superfície da rocha. Em ambos os tipos de politrizes, a velocidade de rotação do satélite é invariável, o que implica em uma velocidade de corte constante. Devido à grande variedade de tipos litológicos que são utilizados para fins ornamentais, a possibilidade de se alterar a velocidade com que o rebolo abrasivo passa sobre a superfície da chapa de rocha pode permitir uma otimização deste processo. Com o propósito de demonstrar a importância da velocidade de corte para o processo, em oposição à idéia de que quanto maior for essa, melhor seria o brilho final das chapas, bem como confirmar a influência das variáveis petrográficas no processo de polimento, três rochas ornamentais brasileiras, conhecidas comercialmente como Verde Labrador, Cinza Castelo e Preto Indiano, foram submetidas a diferentes situações de desgaste, visando aperfeiçoar esta etapa levando em consideração as características intrínsecas dos materiais pétreos. Para esta pesquisa foram definidas 24 situações operacionais distintas, variando pressão de carregamento (1 e 2kgf/cm2), velocidade de rotação de satélite (300, 400, 500 e 600 rpm) e a de exposição do satélite sobre a rocha (1, 2 e 3). Para isso, foi instalado um inversor de frequência em uma politriz semi-automática que possibilitou a variação da velocidade de rotação de satélite para realização dos experimentos. Para conhecer os materiais pétreos foi realizada a caracterização petrográfica e tecnológica. Assim, foram realizados os testes de polimento, sendo cada rocha submetida...
The polishing of dimension stones at industrial scale is done in equipments called polishing machines, and they may be semi-automatic or automatic. Polishing is acquired by the friction generated by the rotational motion of the griding tools fixed on polishing heads under pressure against the stone surface. In both cases the rotation speed of the polishing head is invariable, which implies in a constant cutting speed. Because of the wide variety of lithologies that are used for ornamental purposes, the possibility of changing the speed the griding tools pass over the surface of the slab of stone could allow an optimization of this process. In order to define the importance of cutting speed and opposing the idea that the greater the velocity applied onto the slab, the better brightness is produced, and also to confirm the idea that petrographic variables are also important agents in the polishing process, three Brazilian dimension stones, known commercially as Verde Labrador, Cinza Castelo and Preto Indiano, were subjected to different wear situations, aiming the optimization of this step, taking into consideration the intrinsic characteristics of stone materials. For this research 24 distinct operational situations were defined, varying pressure (1 to 2kgf/cm²), rotational speed of the polishing head (300, 400, 500 and 600 rpm) and the exposure of the polishing head onto the slab of stone (1, 2, and 3). A frequency inverter was installed in a semi-automatic polishing machine which allowed the variation of the speed of the polishing head for these experiments. The stones were petrographically and technologically characterized. The polishing tests were conducted applying, to each kind of stone, 10 sequences of abrasive tools of magnesium type, namely 24, 36, 60, 120, 220, 400, 600, 800, 1200 and lustrum, totalizing 720 samples... (Complete abstract click electronic access below)

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Bolonini, Thiago Motta [UNESP]. "Geologia e potencialidade do granito Vermelho Capão Bonito (Sudoeste do Estado de São Paulo) como rocha ornamental." Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/92882.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
O Maciço Granítico Capão Bonito localiza-se no sudoeste do Estado de São Paulo e está associado à evolução neoproterozóica da Província Mantiqueira Central. As suas rochas afloram junto à borda da Bacia do Paraná em um corpo com forma alongada cujo eixo maior apresenta direção geral NE-SW, perfazendo uma área aproximada de 110km2. Ocorre intrusivo em rochas epimetamórficas da Formação Votuverava, do Grupo Açungui e em rochas graníticas do Complexo Três Córregos e a sua colocação encontra-se relacionada a uma tectônica rúptil das zonas de cisalhamento de direção NE-SW. O contato sul encontra-se delimitado pela Falha do Bairro dos Alves que compõe a Zona de Cisalhamento Quarenta Oitava e por contatos normais com as rochas metassedimentares. Os contatos oeste e noroeste ocorrem com rochas graníticas do Complexo Três Córregos a partir da Falha de Capão Bonito ou Zona de Cisalhamento Itapirapuã, além de apresentar contato também com as rochas metassedimentares da Formação Votuverava. Nos metassedimentos, quando preservados das feições deformacionais impostas pela deformação milonítica, preservam-se texturas e mineralogias do metamorfismo de contato com desenvolvimento de minerais na fácies albita-epidoto e hornblenda hornfels. A região central e norte do maciço caracterizam-se por uma área arrasada constituindo um planalto entre os fortes da serrania com poucos afloramentos na forma de matacões expostos. Os contatos sul e extremo NW do corpo apresentam-se mais íngremes e encontram-se mais dissecados e erodidos, apresentando inúmeras exposições das litologias do maciço com riqueza de matacões e lajedos expostos ou com coberturas de solo menos espessas, contribuindo, portanto, para o direcionamento das frentes de lavra. No contato norte do maciço...
The Capão Bonito Granitic Massif is located in the southwestern of São Paulo state and is related to the evolution neoprotherozoic of the Mantiqueira Central Province. Its rocks outcrop along the edge of the Paraná Basin in a body with elongated major axis shows the general direction of NE-SW, covering an area of approximately 110km2. Occurs intrusive on epi-metamorphic rocks of the Votuverava Formation, Açungui Group and granitic rocks of the Três Córregos Complex and their placement is related to a ruptile tectonics of shear zones in NE-SW direction. The south contact is limited by the failure of the Alves district comprising Quarenta Oitava shear zone and normal contacts with the metasedimentary rocks. The western and northwestern contacts occur, with granitic rocks of the Três Córregos Granitic Complex from the Capão Bonito failure or Itapirapuã shear zone, and also perform contact with the metasedimentary rocks of Votuverava Formation. In the metasediments, when preserved the features of deformation imposed by mylonitic deformation, to preserve texture and mineralogy of contact metamorphism with development of minerals in the albite-epidote facies and hornblende hornfels. The central region and north of the massif are characterized by a flattened area forming a plateau between the strong from the mountains with few outcrops in the form of boulders exposed. The south and the extreme NW contacts of the body have become more steep and are more dissected and eroded, presenting numerous exhibitions lithology with the massive wealth of exposed boulders and flagstones or less thick soil cover, contributing thus to the direction of the quarries. In the north contact of the massif rocks, are small pits or rock exposures associated mainly with the headwaters of drainages, because they have... (Complete abstract click electronic access below)

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25

Pazeto, Abiliane de Andrade. "Correlação entre propriedades petrográficas e comportamento tecnológico e de alterabilidade das rochas ornamentais silicáticas Diamante Negro (BA), Ocre Itabira e Banco Galaxy (ES) /." Rio Claro : [s.n.], 2011. http://hdl.handle.net/11449/92883.

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Orientador: Antonio Carlos Artur
Banca: Tamar Milca Bortolozzo Galembeck
Banca: Fabiano Cabañas Navarro
Resumo: O objetivo da presente pesquisa foi estabelecer a correlação entre as propriedades petrográficas e o comportamento tecnológico e de alterabilidade de três materiais utilizados como rochas ornamentais e para revestimento. Os tipos petrográficos correspondem a um microgabro (Diamante Negro), um hornblenda sienito pórfiro com quartzo (Ocre Itabira) e um granito pegmatóide com granada e sillimanita (Branco Galaxy), sendo o primeiro proveniente do estado da Bahia e os dois últimos do estado do Espírito Santo. Os materiais foram caracterizados petrograficamente e submetidos a uma bateria de ensaios físico-mecânicos e de alteração acelerada que compreenderam determinações de índices físicos, desgaste abrasivo Amsler, compressão uniaxial simples, resistência à flexão 3 e 4 pontos, impacto de corpo duro, velocidade de propagação de ondas ultrassônicas longitudinais, coeficiente de dilatação térmica linear e resistência ao ataque químico sob efeito de compostos agressivos e em câmaras saturadas em atmosfera salina e dióxido de enxofre (SO2). Os resultados demonstram que o comportamento tecnológico das rochas está intrinsecamente relacionado aos aspectos mineralógicos, estruturais e texturais inerentes a cada tipo petrográfico. O Diamante Negro é o material detentor dos maiores índices físico-mecânicos, uma vez que suas características petrográficas são marcadas por granulação fina, bom entrelaçamento mineral, e baixo grau de microfissuramento. Quanto à alteração acelerada, no entanto, apresentou variações cromáticas consideráveis, dado seu elevado teor de minerais máficos. O tipo comercial Ocre Itabira também apresentou boas propriedades tecnológicas, com valores inferiores ao Diamante Negro devido principalmente à sua granulação... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The objective of this research was correlating petrographical properties to the technological and alterability behavior of three materials used as ornamental and building stones. The samples correspond to a microgabbro (Diamante Negro), a hornblende porphiral syenite with quartz and (Ocre Itabira) a pegmatoid granite with garnet and sillimanite (Branco Galaxy), being the first sample originating from the Bahia state and the last one from Espírito Santo state. The materials were petrographically analyzed and submitted to physical mechanics tests and chemical alterability including measurements of physical indexes, abrasion resistance, compressive strength, modulus of rupture, flexural strength, impact strength, ultrasonic pulse velocity, linear thermal expansion coefficient and resistance to the chemical attack accomplished by aggressive compositions and chambers which simulate both sea-salt and sulphur dioxide weathering. The results reveal the influence of minerals, textural and structural features over the studied stones behavior during the performed tests. Diamante Negro is the material which showed the highest physical-mechanics properties, once their petrographical parameters correspond to fine grain size, good mineral interlacement, and low microcrack degree. However, relating to the chemical alterability it showed considerable chromatic deterioration, given its high content of mafic minerals. The commercial type Ocre Itabira also presented good technological properties, with inferior values than Diamante Negro due to its large grain size granulation and high degree of relative microcracking. The brownish coloration of potash feldspars porphyries present in its mineralogical composition turned the effects caused by the chemical reagents less evident. In general, Branco Galaxy presented the smallest values of... (Complete abstract click electronic access below)
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26

Camargo, Jefferson Luiz. "Influência das propriedades petrográficas na qualidade do polimento de rochas ornamentais /." Rio Claro, 2013. http://hdl.handle.net/11449/92856.

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Orientador: Antonio Carlos Artur
Coorientador: Leonardo Luiz Lyrio da Silveira
Banca: Tamar Milca Bortolozzo Galembeck
Banca: Rogério Pinto Ribeiro
Resumo: O polimento de rochas ornamentais em escala industrial é realizado em equipamentos denominados politrizes, podendo estes serem semi-automáticos ou automáticos. O polimento é realizado pelo atrito gerado no movimento rotacional de elementos abrasivos dispostos em cabeçotes, denominados satélites, sob pressão, contra a superfície da rocha. Em ambos os tipos de politrizes, a velocidade de rotação do satélite é invariável, o que implica em uma velocidade de corte constante. Devido à grande variedade de tipos litológicos que são utilizados para fins ornamentais, a possibilidade de se alterar a velocidade com que o rebolo abrasivo passa sobre a superfície da chapa de rocha pode permitir uma otimização deste processo. Com o propósito de demonstrar a importância da velocidade de corte para o processo, em oposição à idéia de que quanto maior for essa, melhor seria o brilho final das chapas, bem como confirmar a influência das variáveis petrográficas no processo de polimento, três rochas ornamentais brasileiras, conhecidas comercialmente como Verde Labrador, Cinza Castelo e Preto Indiano, foram submetidas a diferentes situações de desgaste, visando aperfeiçoar esta etapa levando em consideração as características intrínsecas dos materiais pétreos. Para esta pesquisa foram definidas 24 situações operacionais distintas, variando pressão de carregamento (1 e 2kgf/cm2), velocidade de rotação de satélite (300, 400, 500 e 600 rpm) e a de exposição do satélite sobre a rocha (1, 2 e 3). Para isso, foi instalado um inversor de frequência em uma politriz semi-automática que possibilitou a variação da velocidade de rotação de satélite para realização dos experimentos. Para conhecer os materiais pétreos foi realizada a caracterização petrográfica e tecnológica. Assim, foram realizados os testes de polimento, sendo cada rocha submetida... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The polishing of dimension stones at industrial scale is done in equipments called polishing machines, and they may be semi-automatic or automatic. Polishing is acquired by the friction generated by the rotational motion of the griding tools fixed on polishing heads under pressure against the stone surface. In both cases the rotation speed of the polishing head is invariable, which implies in a constant cutting speed. Because of the wide variety of lithologies that are used for ornamental purposes, the possibility of changing the speed the griding tools pass over the surface of the slab of stone could allow an optimization of this process. In order to define the importance of cutting speed and opposing the idea that the greater the velocity applied onto the slab, the better brightness is produced, and also to confirm the idea that petrographic variables are also important agents in the polishing process, three Brazilian dimension stones, known commercially as Verde Labrador, Cinza Castelo and Preto Indiano, were subjected to different wear situations, aiming the optimization of this step, taking into consideration the intrinsic characteristics of stone materials. For this research 24 distinct operational situations were defined, varying pressure (1 to 2kgf/cm²), rotational speed of the polishing head (300, 400, 500 and 600 rpm) and the exposure of the polishing head onto the slab of stone (1, 2, and 3). A frequency inverter was installed in a semi-automatic polishing machine which allowed the variation of the speed of the polishing head for these experiments. The stones were petrographically and technologically characterized. The polishing tests were conducted applying, to each kind of stone, 10 sequences of abrasive tools of magnesium type, namely 24, 36, 60, 120, 220, 400, 600, 800, 1200 and lustrum, totalizing 720 samples... (Complete abstract click electronic access below)
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27

Romano, Pierangelo. "Experimental investigation on peralkaline silicic magmas of Pantelleria Island: inferences on pre-eruptive conditions, magma evolution and water solubility." Doctoral thesis, Università degli Studi di Palermo, 2017. http://hdl.handle.net/10447/221192.

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28

Forsberg, Maria. "Planerat kärnbränsleförvar i Forsmark : - med fokus på episyenit." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-203056.

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It takes a very long time for ionizing radiation of used nuclear fuel toreturn to a natural background level, for this reason one of the requirements for theselection of the location of a repository was that the environment as well people'shealth would be protected from the harmful effect of radioactivity. This requirementmeans that the waste must be isolated in a geological formation. In Sweden therepository will be built in the crystalline bedrock. The location for the Swedish nuclearfuel repository at nearly 500 meters depth at Forsmark in Östhammar was decided 3June 2009. The repository will be located at Söderviken, close to the Forsmarknuclear power plant in a 1.90 billion year old bedrock that will accommodate 12,000tons of spent nuclear fuel. The bedrock of Östhammar is a seismically quiet, howeverthere is a large system of fracture zones and fractures at the site considered to havebeen formed shortly after the ductile shear zone deformaton. The geology isdominated by medium grained metagranite with mafic intrusions. These rock volumeshave been subjected to metamorphism and ductile deformation at c. 1.85 Ga.The site investigations shown that the bedrock composition was asexpected, except for a few locations of a porous granite (episyenite) and a fracturedbedrock down to about 200 meters depth. This rock is relatively uncommon, but mayaffect the quality of the repository. Most episyenites are geographical associated tofractures and fracture zones, but there are exceptions where there are no distinctrelationships to the latter.

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Billur, Basak. "Geology And Petrology Of Beypazari Granitoids: Yassikaya Sector." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12605577/index.pdf.

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Beypazari Granitoid is a low temperature and shallow-seated batholite intruded the Tepekö
y metamorphic rocks of the Central Sakarya Terrane. Composition of the granitoid varies from granite to diorite. The granitoid is unconformably overlain by Palaeocene and Eocene rock units. Thus the age is probably Late Cretaceous. The Beypazari Granitoid comprises mafic microgranular enclaves. The granitoid mainly consists of quartz, plagioclase, orthoclase and minor amphibole, biotite, chlorite, zircon, sphene, apatite, and opaque minerals. Plagioclase shows sericitation whereas biotite and hornblende, chloritization. Holocrystalline and hypidiomorphic are characteristic textures of the granitoid. Geochemically, the Beypazari Granitoid is calc-alkaline, metaluminous and I-type. REE data indicate that it may have been generated from a source similar to the upper continental crust. The trace element data of the Beypazari Granitoid suggest a volcanic arc tectonic setting. The possible mechanism of Beypazari granitoid is the northdipping subduction of Neo-Tethyan northern branch under Sakarya continent during Late Cretaceous. The Beypazari Granitoid may be related with Galatean volcanic arc granitoids.

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30

Kremers, Simon. "Combining experimental volcanology, petrology and geophysical monitoring techniques." Diss., lmu, 2012. http://nbn-resolving.de/urn:nbn:de:bvb:19-146595.

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31

Sommacal, Silvano, and silvano sommacal@anu edu au. "Computational petrology: Subsolidus equilibria in the upper mantle." The Australian National University. Research School of Earth Sciences, 2004. http://thesis.anu.edu.au./public/adt-ANU20050415.151025.

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Processes that take place in the Earths mantle are not accessible to direct observation. Natural samples of mantle material that have been transported to the surface as xenoliths provide useful information on phase relations and compositions of phases at the pressure and temperature conditions of each rock fragment. In the past, considerable effort has been devoted by petrologists to investigate upper mantle processes experimentally. Results of high temperatures, high pressure experiments have provided insight into lower crust-upper mantle phase relations as a function of temperature, pressure and composition. However, the attainment of equilibrium in these experiments, especially in complex systems, may be very difficult to test rigorously. Furthermore, experimental results may also require extrapolation to different pressures, temperatures or bulk compositions. More recently, thermodynamic modeling has proved to be a very powerful approach to this problem, allowing the deciphering the physicochemical conditions at which mantle processes occur. On the other hand, a comprehensive thermodynamic model to investigate lower crust-upper mantle phase assemblages in complex systems does not exist. ¶ In this study, a new thermodynamic model to describe phase equilibria between silicate and/or oxide crystalline phases has been derived. For every solution phase the molar Gibbs free energy is given by the sum of contributions from the energy of the end-members, ideal mixing on sites, and excess site mixing terms. It is here argued that the end-member term of the Gibbs free energy for complex solid solution phases (e.g. pyroxene, spinel) has not previously been treated in the most appropriate manner. As an example, the correct expression of this term for a pyroxene solution in a general (Na-Ca-Mg-Fe2+-Al-Cr-Fe3+-Si-Ti) system is presented and the principle underlying its formulation for any complex solution phase is elucidated.¶ Based on the thermodynamic model an algorithm to compute lower crust-upper mantle phase equilibria for subsolidus mineral assemblages as a function of composition, temperature and pressure has been developed. Included in the algorithm is a new way to represent the total Gibbs free energy for any multi-phase complex system. At any given temperature and pressure a closed multi-phase system is at its equilibrium condition when the chemical composition of the phases present in the system and the number of moles of each are such that the Gibbs free energy of the system reaches its minimum value. From a mathematical point of view, the determination of equilibrium phase assemblages can, in short, be defined as a constrained minimization problem. To solve the Gibbs free energy minimization problem a Feasible Iterate Sequential Quadratic Programming method (FSQP) is employed. The systems Gibbs free energy is minimized under several different linear and non-linear constraints. The algorithm, coded as a highly flexible FORTRAN computer program (named Gib), has been set up, at the moment, to perform equilibrium calculations in NaO-CaO-MgO-FeO-Al2O3-Cr2O3-Fe2O3- SiO2-TiO2 systems. However, the program is designed in a way that any other oxide component could be easily added.¶ To accurately forward model phase equilibria compositions using Gib, a precise estimation of the thermodynamic data for mineral end-members and of the solution parameters that will be adopted in the computation is needed. As a result, the value of these parameters had to be derived/refined for every solution phase in the investigated systems. A computer program (called GibInv) has been set up, and its implementation is here described in detail, that allows the simultaneous refinement of any of the end-member and mixing parameters. Derivation of internally consistent thermodynamic data is obtained by making use of the Bayesian technique. The program, after being successfully tested in a synthetic case, is initially applied to pyroxene assemblages in the system CaO-MgO-FeO-Al2O3-SiO2 (i.e. CMFAS) and in its constituent subsystems. Preliminary results are presented.¶ The new thermodynamic model is then applied to assemblages of Ca-Mg-Fe olivines and to assemblages of coexisting pyroxenes (orthopyroxene, low Ca- and high Ca clinopyroxene; two or three depending on T-P-bulk composition conditions), in CMFAS system and subsystems. Olivine and pyroxene solid solution and end-member parameters are refined, in part using GibInv and in part on a trial and error basis, and, when necessary, new parameters are derived. Olivine/pyroxene phase relations within such systems and their subsystems are calculated over a wide range of temperatures and pressures and compare very favorably with experimental constraints.

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32

Eady, Angela Elizabeth. "The petrology and geochemistry of the Acheron intrusion." Thesis, University of Canterbury. Geology, 1995. http://hdl.handle.net/10092/6783.

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Subalkaline transitional gabbros have intruded the Cretaceous - Paleocene sediments of the Acheron Outlier. The gabbroic magma has differentiated in situ to form a laccolith and sill-like apophysis, as well as having a strong thermal effect on the sediments and especially the coals of the Broken River Formation. This research concentrates on the geochemical characteristics and differentiation processes. Additional research on the thermal alteration of the coals at Acheron has provided data for heating models of the sediments. Thermal alteration of the sediments is extensive with the thermal aureole of the intrusion affecting the entire thickness of Tertiary sediments exposed at Acheron, increasing coal ranks from regional lignite A to anthracite. Vitrinite reflectance data indicate circulating hydrothermal fluids had a strong control on the degree of heating sediments underwent. It is suggested that the Acheron magma was modified by flowage differentiation within the conduit prior to emplacement. This created an olivine phenocryst-rich magma and an olivine phenocryst-poor melt. The latter was emplaced into the Tertiary sediments as a thin proto-laccolith which inflated to form the bulk of the Acheron Intrusion prior to the emplacement of the denser and more viscous olivine-rich magma which formed a basal layer within the intrusion and also breached the laccolith margin to form the apophysis. Crystallisation proceeded from the walls, roof and floor by sidewall crystallisation. This produced the five lithotypes recognised within contact gabbro, olivine mela-gabbro, gabbro, monzogabbro and differentiates. Geochemical analyses of these rocks show differentiation trends consistent with crystal fractionation of a relatively basic melt. Geochemical trends are complicated by the extensive deuteric alteration of the intrusion. Alteration of feldspar by late stagedeuteric fluids has produced secondary analcime and other zeolites, as well as quartz, giving the false impression that the intrusion was originally undersaturated.

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33

Parman, Stephen Wayne. "Petrology and geochemistry of high degree mantle melts." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/55064.

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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, February 2001.
Includes bibliographical references.
Experimental phase equilibria, whole rock major and trace element concentrations, and mineral major and trace element concentrations are used to constrain the petrogenesis of high degree, hydrous melts of the mantle, with particular focus on komatiites from the Barberton Mountainland, South Africa. Chapter 1 presents experiments on a Barberton komatiite composition under anhydrous and H20 saturated conditions. A comparison of the compositions of augite in the experiments with augite in the samples indicates that at least 4.5 wt.% H20 was present in the komatiite melts prior to emplacement. The presence of H20 in the magmas would allow them to be produced at lower temperatures than required by anhydrous models of komatiite genesis, and would obviate the need for extremely high temperatures in the Archean mantle. In Chapter 2, ion probe analyses of augite in Barberton komatiites are used to quantify the effects that metamorphism has had on the bulk rock compositions. The results indicate that high field strength elements and most rare earth elements were not significantly mobilized by metamorphism, while Eu and Sr were mobilized. Some Barberton magmas were enriched in light rare earth elements and Sr, and depleted in high field strength elements, which are the chemical characteristics of modem subduction related magmas. Chapter 3 presents melting experiments that explore the effect of H20 on melts in equilibrium with olivine and orthopyroxene at 1.2 to 2.4 GPa. The results of the experiments are used to infer the thermodynamic properties of H20 in silicate melts, and to construct a numerical model that predicts the composition of high degree mantle melts. The model is used to estimate the melting conditions that produced high-MgO andesites, boninites, and komatiites. It is shown that Barberton komatiites can be produced by melting at low pressures (2.4-3.0 GPa) and temperatures (1440-1500 °C). Chapter 4 demonstrates that basaltic komatiites overlap the compositions of modem boninites and display nearly identical trace element systematics. Komatiites are also shown to have numerous chemical similarities to boninites as well. It is proposed that komatiites and basaltic komatiites were produced by the same processes that produce modem boninites. The lack of komatiites in modem subduction zones is attributed to -100*C secular mantle cooling that has occurred since 3.5 Ga.
by Stephen Wayne Parman.
Ph.D.

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34

Parker, Matthew John. "Early prehistoric petrology : a case study from Leicestershire." Thesis, University of Bradford, 2013. http://hdl.handle.net/10454/6310.

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This research focused on the petrographic analysis of prehistoric ceramics within the East Midlands. Prior assessments have been intermittent and not drawn together by a research-based agenda, with a few notable exceptions. This research uses petrographic analysis to shed light on early prehistoric society within Leicestershire, a county overlooked in comparison to other regions. The aim of this research was to investigate the procurement of raw materials and the subsequent production of Neolithic and early Bronze Age ceramics in Leicestershire, placing the county in its regional context. Petrographic slides from several early prehistoric sites were produced and analysed to determine the presence of any non-local material within the fabric of the ceramics. Existing petrographic data from other sites in the East Midlands were used as a comparative data set to test whether the ceramics from Leicestershire were typical or atypical of the wider production and procurement pattern. The results of the petrographic analysis on the Leicestershire sites indicated that the clay and inclusions were most likely of local origin, with no definitive evidence for non-local inclusions. However, the results from the comparative petrographic data obtained from sites within the wider East Midlands does support the movement of raw materials and/or finished ceramic products within the region. Preferential sources appear to have been continually exploited, both chronologically and geographically. The prime target of the exploitation was the Charnwood Forest area of Leicestershire, with groups from Derbyshire and Nottinghamshire utilising this resource in addition to more local groups within Leicestershire.

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35

Block, Kristin. "Fulgurite Classification, Petrology, and Implications for Planetary Processes." Thesis, The University of Arizona, 2011. http://hdl.handle.net/10150/144596.

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A variety of fulgurites from diverse locations have been studied. Morphological features were measured and physical properties documented, and a classification scheme was developed. Three major types are introduced and described: Type I, Type II, and Type III, along with two minor types: Type IV and Melt Droplets. Fulgurites representative of each major taxonomic type were investigated using electron microprobe point analyses and x-ray mapping. A range of compositions were found, including nearly pure glass, detrital zircons with baddeleyite rims, Fe-metal with P-rich rims, and unusual Fe-Si metals. The fulgurite formation process is considered within the planetary context through a discussion of lightning detection and potential for formation on other terrestrial bodies. Finally, suggestions for future investigations are presented and discussed.

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36

Parker, Matthew J. "Early prehistoric petrology: A case study from Leicestershire." Thesis, University of Bradford, 2013. http://hdl.handle.net/10454/6310.

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This research focused on the petrographic analysis of prehistoric ceramics within the East Midlands. Prior assessments have been intermittent and not drawn together by a research-based agenda, with a few notable exceptions. This research uses petrographic analysis to shed light on early prehistoric society within Leicestershire, a county overlooked in comparison to other regions. The aim of this research was to investigate the procurement of raw materials and the subsequent production of Neolithic and early Bronze Age ceramics in Leicestershire, placing the county in its regional context. Petrographic slides from several early prehistoric sites were produced and analysed to determine the presence of any non-local material within the fabric of the ceramics. Existing petrographic data from other sites in the East Midlands were used as a comparative data set to test whether the ceramics from Leicestershire were typical or atypical of the wider production and procurement pattern. The results of the petrographic analysis on the Leicestershire sites indicated that the clay and inclusions were most likely of local origin, with no definitive evidence for non-local inclusions. However, the results from the comparative petrographic data obtained from sites within the wider East Midlands does support the movement of raw materials and/or finished ceramic products within the region. Preferential sources appear to have been continually exploited, both chronologically and geographically. The prime target of the exploitation was the Charnwood Forest area of Leicestershire, with groups from Derbyshire and Nottinghamshire utilising this resource in addition to more local groups within Leicestershire.

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37

Sommacal, Silvano. "Computational petrology : subsolidus equilibria in the upper mantle /." View thesis entry in Australian Digital Theses Program, 2004. http://thesis.anu.edu.au/public/adt-ANU20050415.151025/index.html.

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38

Nejedlik, John. "Petrographic image analysis as a tool to quantify porosity and cement distribution." Title page, contents and abstract only, 2001. http://web4.library.adelaide.edu.au/theses/09SM/09smn417.pdf.

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Includes bibliographical references (leaves 153-157). Petrographic image analysis proved particularly useful in determining the parameters for statistical analysis for the simple mineralogies displayed in the samples from the Hutton Sandstone. Concentrates on establishing techniques for statistical study of data collected by PIA to subdivide the framework grains from the porosity or cement.

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39

Bolonini, Thiago Motta. "Geologia e potencialidade do granito "Vermelho Capão Bonito" (Sudoeste do Estado de São Paulo) como rocha ornamental /." Rio Claro : [s.n.], 2011. http://hdl.handle.net/11449/92882.

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Orientador: Antonio Misson Godoy
Banca: Antonio Carlos Artur
Banca: Leonardo Luiz Lyrio da Silveira
Resumo: O Maciço Granítico Capão Bonito localiza-se no sudoeste do Estado de São Paulo e está associado à evolução neoproterozóica da Província Mantiqueira Central. As suas rochas afloram junto à borda da Bacia do Paraná em um corpo com forma alongada cujo eixo maior apresenta direção geral NE-SW, perfazendo uma área aproximada de 110km2. Ocorre intrusivo em rochas epimetamórficas da Formação Votuverava, do Grupo Açungui e em rochas graníticas do Complexo Três Córregos e a sua colocação encontra-se relacionada a uma tectônica rúptil das zonas de cisalhamento de direção NE-SW. O contato sul encontra-se delimitado pela Falha do Bairro dos Alves que compõe a Zona de Cisalhamento Quarenta Oitava e por contatos normais com as rochas metassedimentares. Os contatos oeste e noroeste ocorrem com rochas graníticas do Complexo Três Córregos a partir da Falha de Capão Bonito ou Zona de Cisalhamento Itapirapuã, além de apresentar contato também com as rochas metassedimentares da Formação Votuverava. Nos metassedimentos, quando preservados das feições deformacionais impostas pela deformação milonítica, preservam-se texturas e mineralogias do metamorfismo de contato com desenvolvimento de minerais na fácies albita-epidoto e hornblenda hornfels. A região central e norte do maciço caracterizam-se por uma área arrasada constituindo um planalto entre os fortes da serrania com poucos afloramentos na forma de matacões expostos. Os contatos sul e extremo NW do corpo apresentam-se mais íngremes e encontram-se mais dissecados e erodidos, apresentando inúmeras exposições das litologias do maciço com riqueza de matacões e lajedos expostos ou com coberturas de solo menos espessas, contribuindo, portanto, para o direcionamento das frentes de lavra. No contato norte do maciço... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The Capão Bonito Granitic Massif is located in the southwestern of São Paulo state and is related to the evolution neoprotherozoic of the Mantiqueira Central Province. Its rocks outcrop along the edge of the Paraná Basin in a body with elongated major axis shows the general direction of NE-SW, covering an area of approximately 110km2. Occurs intrusive on epi-metamorphic rocks of the Votuverava Formation, Açungui Group and granitic rocks of the Três Córregos Complex and their placement is related to a ruptile tectonics of shear zones in NE-SW direction. The south contact is limited by the failure of the Alves district comprising Quarenta Oitava shear zone and normal contacts with the metasedimentary rocks. The western and northwestern contacts occur, with granitic rocks of the Três Córregos Granitic Complex from the Capão Bonito failure or Itapirapuã shear zone, and also perform contact with the metasedimentary rocks of Votuverava Formation. In the metasediments, when preserved the features of deformation imposed by mylonitic deformation, to preserve texture and mineralogy of contact metamorphism with development of minerals in the albite-epidote facies and hornblende hornfels. The central region and north of the massif are characterized by a flattened area forming a plateau between the strong from the mountains with few outcrops in the form of boulders exposed. The south and the extreme NW contacts of the body have become more steep and are more dissected and eroded, presenting numerous exhibitions lithology with the massive wealth of exposed boulders and flagstones or less thick soil cover, contributing thus to the direction of the quarries. In the north contact of the massif rocks, are small pits or rock exposures associated mainly with the headwaters of drainages, because they have... (Complete abstract click electronic access below)
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40

Carlin, Aline de Cássia. "Características petrográficas e químicas das rochas encaixantes das mineralizações auríferas do depósito Lavra Velha (região de Ibitiara, borda oeste da Chapada Diamantina, Bahia) /." Rio Claro, 2016. http://hdl.handle.net/11449/144713.

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Orientador: Guillermo Rafael Beltran Navarro
Banca: Antenor Zanardo
Banca: Gergely Andres Julio Szabó
Resumo: O depósito de ouro Lavra Velha, que pertence ao Alvo de Prospecção Lavra Velha, da empresa Yamana Gold, localiza-se na cidade de Ibitiara, centro-oeste do Estado da Bahia e borda oeste do domínio fisiográfico da Chapada Diamantina, situado no Aulacógeno do Paramirim, na região norte do Cráton São Francisco. O depósito foi recentemente inserido na classe de modelo IOCG (Iron Oxide Cooper Gold), onde a mineralização de ouro se hospeda em brechas hematíticas sericitizadas. O principal objetivo do trabalho foi caracterizar química e petrograficamente as rochas encaixantes do depósito Lavra Velha, cujas litologias predominantes são metatonalitos e meta-quartzo diorito. Estas rochas encontram-se completamente alteradas, com atuação dos processos hidrotermais predominando sobre a deformação de baixo strain, resultando em intensa sericitização e formação de óxidos de ferro, além de cloritização, epidotização, carbonatação e, localmente, albitização. A análise petrográfica, suportada pela análise química, sugere que as rochas encaixantes são correspondentes alteradas do Granitoide Ibitiara, metamorfizadas, deformadas e alteradas hidrotermalmente. O Granitoide Ibitiara e o Granito Matinos apresentam comportamento de magmatismo misto e afinidade para ambiente de arco magmático (sin-colisional) ou orogênico, com idades correlatas ao ciclo orogênico Transamazônico. A intrusão do Granitoide Ibitiara ocorre, provavelmente, em ambiente mais raso da crosta, sugerindo que fluidos hidrotermais ... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The Lavra Velha gold deposit, which belongs to the prospecting target "Lavra Velha" of the Yamana Gold Company, is located in Ibitiara, Bahia's central west and the western edge of the physiographic domain of the Chapada Diamantina, situated in Paramirim aulaconge, in northern of São Francisco Craton. The deposit was recently insert into the IOCG model class (Iron Oxide Cooper Gold), where the gold mineralization is hosted at hematite sericitic breccias. The main objective of the study was the chemical and petrographic characterization of the host rocks of the Lavra Velha deposit, whose predominant lithologies are meta-tonalites and metaquartz diorite. These rocks are completely altered due to hydrothermal process, that predominates under the deformation at low-strain rate, resulting in intense sericitization and iron oxide formation, also chloritization, epidotization, carbonatation and, locally, albitization. The petrographic analysis, supported by chemical analysis, suggests that the host rocks correspond to metamorphosed, deformed and hydrothermalized portion of Ibitiara Granitoid. The Ibitiara Granitoid and Matinos Granite show behaviors of mixed magmatism and also affinity for arc magmatic (syn-collisional) or orogenic ambient with correlative age to the Transamazônico Cycle. The Ibitiara Granitoid intrusion probably occurs at a shallower crust environment, suggesting that the hydrothermal and mineralizer fluids are later. In spite of the Lavra Velha deposit has being classified as IOCG's class, the tectonic, structural and hydrothermal analysis suggests that the gold mineralization has originated during Espinhaço basin later deformation stage, related to inversion of the Paramirim aulacogen
Mestre

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41

Luciano, Rejane Lima. "Petrografia e geoquímica das rochas metacarbonatíticas do complexo Angico dos Dias, divisa Bahia/Piauí, Brasil /." Rio Claro, 2016. http://hdl.handle.net/11449/138310.

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Orientador: Antonio Misson Godoy
Banca: Antonio Carlos Artur
Banca: Marcos Aurélio Farias de Oliveira
Banca: Larissa Marques de Araújo
Banca: Fábio Machado Braz
Resumo: Este trabalho verificou que as rochas metacarbonatíticas do Complexo Metacarbonatítico de Angico dos Dias (CMCAD), constituídas principalmente por calcita, apatita, olivina, flogopita e magnetita dispõem-se em dois conjuntos: um localizado na mina de fosfato da Galvani (corpo principal, Campo Alegre de Lourdes-BA) e o outro na Fazenda Pimenteira (Caracol-PI). Variação no conteúdo de apatita, minerais ferro-magnesianos e magnetita configura um acamadamento cumulático e permite individualizar cinco fácies petrográficas (contatos graduais). Além disso, exibem manto intempérico, que resulta no minério de fosfato residual (apatitito). Registram pelo menos três fases deformacionais marcadas por estruturas primárias (acamamento reliquiar - S0) que devido aos processos de transposição (D1) da foliação S1 e da deformação D2 associada às zonas de cavalgamento (S2) se mantêm de forma escassa nas áreas menos deformadas. D2 evolui para um bandamento tectônico vertical (S3) nas zonas de cisalhamento (D3). Dados isotópicos indicam que as rochas metacarbonatíticas, datadas em 2.011±6Ma (U-PB em badeleíta e zircão), originaram-se de uma fonte mantélica enriquecida e que o enriquecimento em 18O é reflexo do reequilíbrio durante o metamorfismo/ hidrotermalismo relacionado ao Evento Brasiliano. Dados petrográficos e de química mineral apontam: que a olivina altera para serpentina, tremolita, antofilita e magnetita; que é comum a exsolução de dolomita em calcitas e de ilmenita em magnetitas e; que os carbonatitos foram parcialmente silicificados. As demais rochas do CMCAD, milonitizadas e metamorfizadas em fácies anfibolito alto (mesopertitas), exibem processo de potassificação (fenitização), metassienito e metassienogranito, além de processos de sericitização, saussuritização e epidotização dos plagioclásios ... (Resumo completo clicar acesso eletrônico abaixo)
Abstract: This study found that the metacarbonatite rocks of the Angico dos Dias Metacarbonatite Complex (CMCAD), consisting mainly of calcite, apatite, olivine, phlogopite and magnetite are arranged in two sets: one located at the phosphate mine Galvani (main body, Campo Alegre de Lourdes-BA) and the other at the Farm Pimenteira (Caracol-PI). Variation in the content of apatite, iron-magnesium minerals and magnetite sets up a cumulatic layering and allows individualize five petrographic facies (gradual contacts). Furthermore, exhibit weathering mantle, which results in the residual phosphate ore (apatite-rock). Register at least three deformational phases marked by primary structures (layering reliquiar - S0) that due to the transposition process (D1) of the foliation S1 and D2 deformation associated with thrust zones (S2) remain scantily the least deformed areas. D2 evolves into a tectonic vertical banding (S3) in the shear zones (D3). Isotopic data indicate that metacarbonatite rocks, dated at 2,011 ± 6Ma (U-PB in baddeleyite and zircon), originated from a mantle source enriched and the enrichment in 18O reflects the rebalancing during metamorphism/hydrothermalism related the Brasiliano Event. Petrography and mineral chemistry data point: the olivine changes to serpentine, tremolite, anthophyllite and magnetite; which it is common to exsolution of dolomite in calcite and ilmenite in magnetite and; that carbonatites were partially silicified. The other rocks CMCAD, mylonite and metamorphosed to amphibolite facies high (perthites) exhibit potassification process (fenitization), metasyenite and metasyenogranite, and sericitization, saussuritization and epidotization processes of plagioclase. The metasomatic/hydrothermal event (medium to high greenschist facies) has regional character and reaches beyond CMCAD rocks the rocks of ... (Complete abstract click electronic access below)
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Nayem, Saleh Lehbib. "Estudio Geológico y Metalogenético del Basamento Precámbrico del Sahara Occidental." Doctoral thesis, Universitat de Barcelona, 2016. http://hdl.handle.net/10803/402471.

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En el Sáhara Occidental hay dos unidades principales: la cobertera sedimentaria del Fanerozoico y un basamento cristalino que forma parte del cratón del África Occidental, constituido desde el Paleoarcaico al Paleoproterozoico. A su vez, en el basamento se ha definido una serie de dominios o terranes, delimitados por fallas regionales, que responden a microcontinentes que colisionaron principalmente durante la orogenia Birimiense y la Hercínica. Los primeros estadios de granitización parecen producirse entre el Paleoproterozoico y el Mesoproterozoico dependiendo del dominio, pero el primer gran episodio de plutonismo de tipo TTG generalizado es en la orogenia Leoniana (hacia 3 Ga). Se forman importantes depósitos de BIF en cuencas de “greenstone belts”. El ciclo Liberiense comienza con diques y “sills” ultrabásicos asociados a una pluma mantélica, que evoluciona a una LIP constituida por enjambres de diques de diabasa; en el resto de sectores se produce la individualización de los microcontinentes. El final del ciclo implica la colisión parcial de algunos de estos dominios y procesos de subducción que generan magmatismo calcoalcalino. El proceso de rift en el límite Arcaico- Proterozoico produce magmatismo alcalino saturado y subsaturado, con indicios de elementos raros. Localmente se individualizan cuencas sedimentarias submarinas en las que se forman depósitos importantes de BIF. Durante el Paleoproterozoico se produce la convergencia de la mayoría de las microplacas; en las zonas de suprasubducción se produce un magmatismo calcoalcalino; con el cierre de los océanos y la colisión continental se forman complejos ofiolíticos, a veces con mineralizaciones de Cr-PGE y depósitos de oro orogénico. Esta orogenia produce la cratonización de la mayor parte de los dominios. Los granitos alcalinos asociados al rift posterior son en cambio estériles. El magmatismo calcoalcalino asociado a la orogenia Kibariense en el margen occidental del crató n no par ece haber gener ado depósitos, pero los granitos alcalinos que cierran el ciclo contienen concentraciones muy altas de REE y Nb. La orogenia Panafricana determina la aparición de magmatismo calcoalcalino en el borde occidental del cratón, así como una nueva colisión con el dominio oriental de los Mauritánides, que se cratoniza. El proceso de rifting subsecuente genera rocas alcalinas saturadas y subsaturadas estériles. Los márgenes continentales así formados facilitan la sedimentación de series de plataforma del Paleozoico, en los que se encuentran mineralizaciones de Fe oolítico en el Devónico inferior. Durante la orogenia hercínica se produce la colisión continental de todos estos dominios y Laurussia, formándose el supercontinente de Pangea. En este contexto los cabalgamientos asociados pueden formar mineralizaciones de oro orogénico, y pueden darse mineralizaciones de Cr podiforme (PGE) en ofiolitas. Finalmente, la apertura del Atlántico N desde el Triásico superior-Jurásico produce el desarrollo de carbonatitas en el dominio más occidental de los Mauritánides, asimismo con mineralización de elementos raros. Los márgenes continentales así formados permiten el desarrollo de series de plataforma ricas en yacimientos de fosfatos y con potencial para petróleo. En el curso de este t rabajo se han descubierto varios depósitos minerales, pr incipalmente en el basamento del Precámbrico. Los depósitos de menas metálicas más interesantes son los siguientes: a) Los depósitos ortomagmáticos de Cr- PGE -Ti-V en el complejo estratiforme de Bir Malhat, con continuidades de decenas de km b) Los depósitos de Cr-PGE en cromititas podiformes en contextos oceánicos del Proterozoico de los Mauritánides. c) Los depósitos de Au-(PGE) orogénico asociados a zonas de cizalla, tanto en forma de listwänitas-birbiritas, sistemas filonianos o mineralizaciones estratoligadas asociadas a los mismos, correspondiendo a cizallas formadas en épocas panafricanas (dominios de Tifariti-Bir Lehlu-Ain ben Tili y de Sfariat) o hercínicas (Mauritánides). d) Los depósitos de BIF en series submarinas; si bien estos depósitos se encuentran en todos los dominios, los más interesantes por su continuidad y leyes se encuentran en las zonas de Sfariat y Miyec-Ijil. e) depósitos de Nb-Ta-LREE-U-Fe-V- P-Mo en carbonatitas, importantes tanto en las de edades del Proterozoico como en las del Cretácico. f) depósitos de Nb-Ta-F-HREE-U-Th en rocas alcalinas saturadas o subsaturadas, preferentmente en las enriquecidas en F. g) depósitos de Fe oolítico en las series de plataforma del Devónico inferior, de grandes reservas. h) depósitos de fosforitas y petróleo asociados a la cuenca sedimentaria de El Aaiún. i) Depósitos de U-(REE??) de edad Cuaternario , asociados a calcretas y ferricretas.
Two main geological units are distinguished in Western Sahara: a Phanerozoic sedimentary cover and a cryst a lline basement o f Paleoarchean to Paleoproterozoic age. This basement is a part of the Reguibat ridge, in the Western Africa craton. An ensemble of domains (or terranes) are distinguished in the basement. These domains are limited by regional fauls and correspond to old microcontinents collisioned mainly during the Birimian and Hercynian orogenies. Earlier granitization stages were produced in the Paleoarchean and the Mesoarchean depending on the domain, but the first generalized episode of TTG plutonism occurs in the Leonian orogeny ( circa 3 Ga). Important BIF deposits formed in greenstone belt basins. The Liberian cycle start with the intrusion of ultrabasic sills and dykes, associated with a mantle plume. This scenario evolved to a LIP made up by a dense network of diabase dykes; the individualization of the microcontinents took place in the rest of the area. Convergence of some of these microplates pr oduced subduction and a calc-alkaline magnatism and finally a collision between some of these domains at the end of this cycle. Rifting at the limit Archean-Proterozoic generated saturated and subsaturated alkaline magmatism. Showings of rare- element mineralization occur in these rocks. Submarine sedimentary basins are locally developed, and contain important BIF deposits. Most of the microplates converged during the Paleoproterozoic; calc-alkaline magmatism do occur in the suprasubduction zones; closing of the oceans and subsequent continental collision is associated with development of Cr- (PGE) bearing ophiolitic suites. Regional shear zones are associated with orogeenic gold deposits. This Birimain orogen produced the cratonization of most of the domains.. Alkaline granites intruded in a rft stage at the end of the orogeny, but they are barren. Calc-alkaline magmatism is also present during the Kibarian and Panafrican orogeny at the west border of the WAC, and is not mineralized; however, the alkaline granites of the rifting closing the Kibaran orogeny contain high concentrations of Nb and REE; those at the end of the end of the Panafrican are devoid of mineralization.. The continental margins of the craton allowed the sedimentation of thick platform series during the Paleozoic. The lower Devonian series hosts oolitic iron deposits. The general collision of all these domains and Laurussia during the Hercynian orogeny produced the Pangea supercontinent. In this context, the thrusts can carry orogenic gold deposits, and podiform Cr-(PGE) deposits outcrop in ophiolites. Finally, the opening of the North Atlantic since the Upper Triassic-Jurassic produced carbonatites at the western end of the WAC ; these carbonatites are enriched in rare elements. The continental margins formed in this epoch allowed the sedimentation of platform series thaht contain phospate deposits and have potential to contain oil. Western Sahara has a large potential for ore deposits, and some of them have been discovered during the development of this memory; most of them are hosted in the Precambrian materials: a) Stratiform Cr-PGE -Ti-V deposits associated with the Bir Malhat complex, and their continuity overpass 20 km. b) Podiform Cr-PGE chromitite deposits were produced in the Proterozoic of the Mauritanids. c) Orogenic gold deposits (Au-(PGE) are associated with the regional shear zones. There are several styles of mineralization: listwänites- birbirites, vein systems, or stratabound mineralizations replacing favourable host rocks in the vicinity of shear zones formed during the Birimian orogeny (Tifariti-Bir Lehlu-Ain ben Tili and Sfariat domains) o the Hercynian (Mauritanids). d) BIF deposits in submarine series. These deposits occur in most of the domains, but the Sfariat and Miyec-Ijil domains contain most of the largest reserves. e) Deposits of rare elements as Nb-Ta- LREE-U-Fe-V-P-Mo occur in the Proterozoic and Cretaceous carbonatites. f) Deposits of Nb-Ta-F-HREE-U-Th are found in undersaturated or saturated alkaline rocks, mainly in those enriched in F. g) Oolitic iron deposits have large reserves in the platform series of the Lower Devonian. h) World-class stratiform phosphorite deposits occur in the Paleogene El Aaiún sedimentary basin, which has also potential for oil deposits. i) Calcrete and ferricrete U-(REE??) deposits of Quaternary age.

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White, Thomas West Steltenpohl Mark G. "Geology of the 1:24,000 Tallassee, Alabama, Quadrangle, and its implications for southern Appalachian tectonics." Auburn, Ala, 2008. http://repo.lib.auburn.edu/EtdRoot/2008/SPRING/Geology_and_Geography/Thesis/White_Thomas_41.pdf.

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Lindeberg, Tomas. "Indium Analysis and Small-scale Distribution in Sulphides from the Lindbom Prospect, Långban Area, Western Bergslagen Ore Province." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-196479.

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Indium is extensively used in LCD screens and solar cells. It is mainly produced as a byproduct during ore processing. With ever increasing demand for indium and most of the production being restricted to a few countries new sources for indium are needed. In Sweden, the westernmost Bergslagen is the only area, which is known to exhibit minerals with essential indium. The indium mineralisations at Långban, the Linbom prospect, which are studied in this bachelor’s thesis show several trends. The most notable is the copper indium trend seen in sphalerite. A likely substitution based on similar ionic radii and charges is Cu1++ In3+ ↔ 2Zn2+.Usually when cassiterite is associated with similar polymetalic indium bearing mineralisations as at Långban there is also high concentrations in cassiterite. This has previously not observed in Sweden, however during this project concentrations were indeed found in cassiterite.

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Brismo, Ploetz Marcus. "Mikroskopering av opaka faser - en studie från Skyttgruvan, Falun." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-203117.

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In nature there are about 4,500 minerals identified. These can roughly be divided into two groups, opaque phases and non-opaque phases, with the exception that some opaque phases also may act as a non-opaque phase in different circumstances. The division is made on the basis of the optical properties. Opaque phases are nontransparent, which means that a different type of microscope must be used. A conventional microscope uses transmitted light while the microscope for opaque phases or the ore microscope uses reflected light. The reason is that ore minerals often behave in an opaque manner. An ore mineral is actually a regular mineral but with the difference that it is economically advantageous to mine. Many sulphide and oxide minerals are classified as ore minerals. Sulfide and oxide ores are often associated with a particular type of formation environment and are found in a few areas in Sweden. Bergslagen, Skelleftefältet and Norrbotten belong to these areas. The purpose of this studie is to identify the mineralization from Skyttgruvan and Näverbergsgruvan in Falun by using a microscope.
I naturen finns cirka 4,500 mineral identifierade. Dessa kan grovt sett delas upp i två grupper nämligen opaka faser och icke-opaka faser, då bortses dock från undantaget att vissa opaka faser också kan beteé sig som icke-opaka faser under olika omständigheter. Uppdelningen är gjord utifrån mineralens optiska egenskaper. Opaka faser är icke genomskinliga vilket innebär att en annan typ av mikroskop än de konventionella måste användas. Ett konventionellt mikroskop använder sig av genomfallande ljus samtidigt som mikroskop för opaka faser använder sig av påfallande ljus, ett så kallat malmmikroskop. Anledningen till att de kallas just så är för att malmineral ofta är opaka. Ett malmmineral är egentligen ett vanligt mineral men som är ekonomiskt fördelaktigt att bryta. Idag är många sulfid- och oxidmineral klassade som malmmineral. Sulfid och oxidmineral är ofta associerade med en viss typ av bildningsmiljö. Denna typ av bildningsmiljö går att finna spår av på några platser i Sverige. Bergslagen, Skelleftefältet och Norrbotten hör till dessa områden. Syftet med denna studie är att identifiera de opaka faserna som påträffats i stuffer som samlats in från Skyttgruvan och Näverbergsgruvan.

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Ma, Shing-ka'i George. "Petrology of mesozoic-cenozoic volcanic rocks in Northwestern Syria." Click to view the E-thesis via HKUTO, 2010. http://sunzi.lib.hku.hk/hkuto/record/B44136699.

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Perry, Anna F. Parker Donnie Franklin. "Petrology of Cascade Head Basalt, Oregon Coast Range, USA." Waco, Tex. : Baylor University, 2007. http://hdl.handle.net/2104/5079.

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O'Neill, Anthony Michael. "The petrology of the Tertiary dykes of central Skye." Thesis, University of Oxford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318963.

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McLeod, Claire Louise. "An investigation of crustal contamination through petrology and geochemisty." Thesis, Durham University, 2012. http://etheses.dur.ac.uk/3566/.

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The contamination of mantle-derived magmas by the continental crust is an important process during petrogenesis of volcanic rocks at active continental margins e.g. The Andes. Investigating the evolution of continental arc magmas is, however, hampered by our limited knowledge of, and poor constraints on, the nature of the underlying crustal basement and the mechanisms of crustal anatexis. This thesis reports results from: 1) a whole rock geochemical and in-situ geochronological investigation of a suite of crustal xenoliths from the Bolvian Altiplano, Central Andes; 2) a whole rock geochemical study of the xenoiths’ host lavas and; 3) detailed in-situ geochemical studies of crustal partial melts (quenched to glasses) trapped within their crustal progenitors from Bolivia, NE China and SE Spain. Sampled crustal xenoliths from the Bolivan Altiplano provide a rare insight into the nature of the Central Andean continental basement and reveal lithological and geochemical heterogeneity exists at depth with 87 Sr/86 Sr values extending to 0.7368 which is more radiogenic than any Srisotopic signature exhibited by the recent (< 60 Ma) volcanic record. In-situ U-Pb dating of zircon separates reveal predominant age peaks at 1.7-1.9 Ga, 1.0-1.2 Ga and 495-380 Ma which correspond to periods of supercontinent formation and break-up e.g. construction of Rodinia. Lavas erupted from monogenetic centres on the eastern Bolivian Altiplano show petrographic and geochemical evidence for crustal contamination. The geochemical heterogeneity exhibited by the lavas is, however, difficult to reconcile through simple two component crust-magma interaction models (bulk mixing, AFC and EC-AFC). Instead, contamination is inferred to have involved numerous crustal components. The geochemical signatures observed in lavas from monogenetic centres towards the active Andean arc (between ~18-21o S) are distinct (e.g. lower 87 Sr/86 Sr, higher Sr/Y, higher Ba/Nb at higher Zr/Nb) and may indicate a lower degree of crust-magma interaction, an increase in the contribution from slab-derived fluids and thinner crust arc-wards, the latter which has previously been inferred from geophysical studies. In-situ analysis of anatectic melts reveals that Sr-isotopic disequilibrium between a crustal melt and its source can exist on the sub-millimetre scale. This is understood to reflect the melting of aged minerals with different Rb/Sr (and therefore 87 Sr/86 Sr) more quickly than the isotopic composition can diffusively equilibrate between melt and minerals. Results suggest therefore that crustal anatexis can produce melts which are geochemically heterogeneous both spatially and temporally. This highlights the need for detailed microscopic investigations coupled with petrogenetic modelling in order to develop a more robust characterisation and well-constrained quantification of crustal contamination in open magmatic systems.

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Ma, Shing-ka'i George, and 馬興闓. "Petrology of mesozoic-cenozoic volcanic rocks in Northwestern Syria." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2010. http://hub.hku.hk/bib/B44136699.

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Dissertations / Theses on the topic 'Petrology'

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