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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Geoqu?mica de elementos maiores e tra?os de granitoides neoproterozoicos da prov?ncia Borborema e sua correla??o com propriedades f?sicas de rochas

Fillippi, Rafael Rabelo 28 March 2014 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-03-02T23:01:37Z No. of bitstreams: 1 RafaelRabeloFillippi_DISSERT.pdf: 8469241 bytes, checksum: ac6cb9fb5fb4fcdccacbf04d77937148 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-03-04T22:04:08Z (GMT) No. of bitstreams: 1 RafaelRabeloFillippi_DISSERT.pdf: 8469241 bytes, checksum: ac6cb9fb5fb4fcdccacbf04d77937148 (MD5) / Made available in DSpace on 2016-03-04T22:04:08Z (GMT). No. of bitstreams: 1 RafaelRabeloFillippi_DISSERT.pdf: 8469241 bytes, checksum: ac6cb9fb5fb4fcdccacbf04d77937148 (MD5) Previous issue date: 2014-03-28 / O presente trabalho discute a correla??o de condutividade t?rmica, densidade e susceptibilidade magn?tica com composi??o de elementos maiores e tra?os de corpos ?gneos neoproterozoicos da Prov?ncia Borborema, Nordeste do Brasil. Estas propriedades foram usadas como poss?veis marcadoras entre as su?tes magm?ticas estudadas. Para a correla??o entre propriedades petrof?sicas e geoqu?micas, consideramos um conjunto de 195 an?lises qu?micas de rocha total de granitoides, separadas entre si pelo grau de acidez em b?sicas, intermedi?rias e ?cidas. Foram utilizados elementos maiores (SiO2, Al2O3, Fe2O3, MgO, CaO, Na2O, K2O e TiO2) e alguns tra?os (Rb, Sr, Ba, Zr, Th e U) que est?o usualmente ligados ? forma??o dos minerais mais comuns das rochas ?gneas. Os resultados obtidos mostram que o SiO2 ? o que apresenta melhor correla??o positiva com a condutividade t?rmica, enquanto Al2O3, CaO, Fe2O3, MgO e TiO2 exibem correla??o negativa para esta mesma propriedade. A correla??o com a densidade ? inversa ? obtida por estes ?xidos com a condutividade t?rmica. J? a susceptibilidade magn?tica n?o apresentou nenhuma correla??o com os elementos estudados. Os resultados obtidos para condutividade t?rmica e densidade indicam uma tend?ncia do SiO2 e dos ?xidos com maior afinidade com minerais m?ficos (Al2O3, CaO, Fe2O3, MgO e TiO2) em controlar estes par?metros petrof?sicos. O conjunto de amostras foi subdividido em cinco diferentes su?tes magm?ticas, com base em conte?dos litogeoqu?micos: i) peralcalina / alcalina; ii) alcalina; iii) c?lcio alcalina; iv) c?lcio alcalina de alto K; e v) shoshon?tica. A an?lise dos dados mostrou que a condutividade t?rmica e a densidade apresentaram bons resultados na individualiza??o dessas su?tes, notadamente entre as su?tes peralcalina / alcalina, alcalina, c?lcio-alcalina e shoshon?tica. Contudo, a su?te c?lcio-alcalina de alto K mostrou superposi??o com as demais. Por outro lado, a susceptibilidade magn?tica n?o apresentou resultados efetivos na separa??o das cinco su?tes. / This paper discusses the correlation of thermal conductivity, density and magnetic susceptibility with composition of major and trace elements of Neoproterozoic igneous bodies from Borborema Province, Northeastern Brazil. These properties were used as potential markers among the studied magmatic suites. For the correlation between petrophysical and geochemical properties it was considered a set of 195 chemical analyzes of granitoid rocks, separated by the degree of acidity in basic, intermediate and acidic. Major (SiO2, Al2O3, Fe2O3, MgO, CaO, Na2O, K2O and TiO2) and some trace elements (Rb, Sr, Ba, Zr, Th and U) that are usually linked to the formation of the most common minerals of igneous rocks were used. The results show that SiO2 has the best positive correlation with the thermal conductivity, while Al2O3, CaO, Fe2O3, MgO and TiO2 exhibit negative correlation for the same property. The correlation with density is opposite to that one for these oxides with the thermal conductivity. The magnetic susceptibility did not correlate with the elements studied. The results for thermal conductivity and density indicate a tendency of SiO2 and oxides with higher affinity with mafic minerals (Al2O3, CaO, Fe2O3, TiO2 and MgO) in controlling these petrophysical parameters. The set of samples was divided into five different magmatic suites based on their lithogeochemical aspects into: i) peralkaline / alkaline; ii) alkaline; iii) calc-alkaline; iv) high potassium calcium alkaline; and v) shoshonitic. Data analysis showed that the thermal conductivity and density presented good results in the individualization of these suites, notably between peralkaline / alkaline, alkaline suites, calc-alkaline and shoshonitic. However, the high-K calc-alkaline suite overlapped with the other. In contrast, the magnetic susceptibility did not show effective results for separating the five chemical suites.
2

Cartografia geof?sica regional do magmatismo mesozoico (mosquito e sardinha) na Bacia do Parna?ba

Mocitaiba, Leonardo da Silva Ribeiro 04 August 2016 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-02-02T12:43:28Z No. of bitstreams: 1 LeonardoDaSilvaRibeiroMocitaiba_DISSERT.pdf: 3240652 bytes, checksum: ac8d62608bb771516ea0170de5b0e8ba (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-02-07T19:27:49Z (GMT) No. of bitstreams: 1 LeonardoDaSilvaRibeiroMocitaiba_DISSERT.pdf: 3240652 bytes, checksum: ac8d62608bb771516ea0170de5b0e8ba (MD5) / Made available in DSpace on 2017-02-07T19:27:49Z (GMT). No. of bitstreams: 1 LeonardoDaSilvaRibeiroMocitaiba_DISSERT.pdf: 3240652 bytes, checksum: ac8d62608bb771516ea0170de5b0e8ba (MD5) Previous issue date: 2016-08-04 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / A Bacia do Parna?ba ocupa uma imensa ?rea na por??o NE do territ?rio brasileiro, abrangendo v?rios estados do Brasil. Ela ? uma sin?clise paleozoica, que contem registros desde a forma??o e desagrega??o do supercontinente Gondwana. A bacia ? sustentada por um embasamento cristalino desenvolvido ap?s a colis?o entre as plataformas Amaz?nica e Brasileira. Em um contexto tect?nico de ruptura do megacontinente Pangeia no Mesozoico, que levou ? abertura do Oceano Atl?ntico, rochas ?gneas intrusivas (diques e soleiras) e extrusivas, de composi??o b?sica, acomodaram-se na Bacia do Parna?ba, que, do ponto de vista estratigr?fico, foram divididas em duas unidades: Forma??o Mosquito Eojur?ssica e Forma??o Sardinha Eocret?cea. A presente pesquisa tem por objetivo principal a cartografia geof?sica regional desses corpos magm?ticos com base em dados aeromagn?ticos e uma t?cnica de mapeamento semiautom?tico (SOM). O Matched Filter foi aplicado com o objetivo de decompor o Campo Magn?tico An?malo (CMA) da bacia em componentes relacionadas a fontes magn?ticas em diferentes profundidades. Com isso, foram obtidos os campos magn?ticos profundo (CMP), intermedi?rio (CMI) e raso (CMR). Como o CMI apresenta principalmente uma contribui??o causada por fontes magn?ticas em profundidades mais rasas na crosta superior, caracter?stica dos corpos magm?ticos da bacia, aplicamos as t?cnicas de filtragem espectral Amplitude do Sinal Anal?tico e Derivada Vertical nas anomalias magn?ticas do CMI, com o objetivo de real?ar ainda mais a resposta geof?sica dessas fontes magn?ticas, aumentando a resolu??o espacial do m?todo investigativo. Com base nas anomalias de alta amplitude e curto comprimento de onda, delimitamos dom?nios e lineamentos magn?ticos nos mapas aeromagn?ticos, correlacionando-os com os poss?veis corpos causadores. Assim, integrando os mapas geof?sicos com essas assinaturas magn?ticas ao SOM e ao mapa geol?gico, ? apresentado um mapa interpretativo com a distribui??o superficial das anomalias magn?ticas associadas ao Magmatismo Mesozoico da bacia. Os resultados indicaram que o Magmatismo Mosquito tem grande ocorr?ncia nas bordas oeste e sul da bacia, e o Magmatismo Sardinha est? concentrado nas por??es centro-leste e nordeste. Os dados de susceptibilidade magn?tica medidos nas rochas vulc?nicas da bacia individualizaram o Magmatismo Mesozoico, constatando que a Forma??o Sardinha exibe susceptibilidade magn?tica m?dia de 25,2 x 10-3 SI, aproximadamente duas vezes maior que a susceptibilidade magn?tica m?dia da Forma??o Mosquito de 11,46 x 10-3 SI, revelando uma diferencia??o composicional destes dois eventos magm?ticos. Associa??es entre as se??es s?smicas, os dados magn?ticos e o mapa geol?gico demonstraram que as anomalias do CMA e da ASA est?o relacionadas ?s soleiras e diques intrusivos, geralmente nos grupos Serra Grande, Canind? e Balsas, e s?o sensivelmente influenciadas por rochas ?gneas aflorantes ou subaflorantes. Por fim, as dire??es dos lineamentos magn?ticos revelaram que riftes de dire??es ENE-WSW e NNE-SSW, associados ? desagrega??o do Gondwana Oeste, e trends estruturais E-W e NE-SW, associados ? Zona de Cisalhamento Transbrasiliano, exerceram controle estrutural sobre o Magmatismo Mesozoico da bacia do Parna?ba. / The Parna?ba Basin occupies a large area in the NE portion of Brazil, covering several states. It is a Paleozoic syneclise that contains records from the formation and break-up of the Gondwana supercontinent. The basin is supported by a crystalline basement developed after the collision between the Amazonian and Brazilian platforms. During the Mesozoic break-up of the Pangea megacontinent, which contributed to the opening of the Atlantic Ocean, intrusive igneous (dykes and sills) and extrusive rocks took place in the Parna?ba Basin. In the stratigraphic context, those igneous rocks were divided into two units: Early Jurassic Mosquito and Early Cretaceous Sardinha formations. The main objective of this research is a regional geophysical mapping of these magmatic bodies based on aeromagnetic data and self-organizing map technique (SOM). Matched Filter was applied in order to decompose the Total Magnetic Intensity anomalies (TMI) of the basin in their components related to magnetic sources at different depths: Deep (DMF), Intermediate (IMF), and Shallow Magnetic Fields (SMF). As the IMF anomalies mainly present contributions from magnetic sources at shallower depths in the upper crust, characteristics of such magmatic bodies, spectral filtering techniques (Analytic Signal Amplitude and Vertical Derivative) were applied to IMF data in order to enhance the geophysical response of these magnetic sources, increasing the spatial resolution of the investigative method. Based on high amplitude and short wavelength anomalies, magnetic domains and lineaments were delimited in aeromagnetic maps and correlated with the possible causative bodies. Thus, the correlation of the geophysical maps with SOM solutions and the geological map allowed to propose an interpretive map with the surface distribution of magnetic anomalies associated with Mesozoic Magmatism in the Parna?ba basin. The results indicated that the Mosquito Magmatism has great occurrence at the western and southern basin edges and the Sardinha Magmatism is located at the centraleastern and northeastern parts. Magnetic susceptibility data, measured in the magmatic rocks, permitted individualizing the Mesozoic Magmatism.The Sardinha Formation displays average magnetic susceptibility of 25.2 x 10-3 SI, about two times higher than the values of 11.46 x 10 -3 SI obtained to Formation Mosquito, revealing a compositional differentiation of these two magmatic events. Associations between seismic sections, magnetic data and geological map showed that the high amplitude anomalies in the Analytic Signal and TMI maps are associated with sills and dykes intruded usually within Balsas, Canind? and Serra Grande groups, and are significantly influenced by outcropping or at near-surface buried igneous rocks. Finally, the directions of the magnetic lineaments revealed that ENE-WSW and NNE-SSW oriented rifts, associated with the break-up of West Gondwana, and E-W and NE-SW structural trends, associated with Transbrasiliano Shear Zone, exercised structural control over the Mesozoic Magmatism of the Parna?ba basin.

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