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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.
11

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.
12

Proposta metodol?gica para o imageamento, caracteriza??o, parametriza??o e gera??o de modelos virtuais de afloramentos

Souza, Anderson de Medeiros 31 January 2013 (has links)
Made available in DSpace on 2015-02-24T19:48:44Z (GMT). No. of bitstreams: 1 AndersonMS_TESE_inicio_pag69.pdf: 4445825 bytes, checksum: 1053632581a0015bab09d4146df22458 (MD5) Previous issue date: 2013-01-31 / Petr?leo Brasileiro SA - PETROBRAS / The aim of this work was to describe the methodological procedures that were mandatory to develop a 3D digital imaging of the external and internal geometry of the analogue outcrops from reservoirs and to build a Virtual Outcrop Model (VOM). The imaging process of the external geometry was acquired by using the Laser Scanner, the Geodesic GPS and the Total Station procedures. On the other hand, the imaging of the internal geometry was evaluated by GPR (Ground Penetrating Radar).The produced VOMs were adapted with much more detailed data with addition of the geological data and the gamma ray and permeability profiles. As a model for the use of the methodological procedures used on this work, the adapted VOM, two outcrops, located at the east part of the Parnaiba Basin, were selected. On the first one, rocks from the aeolian deposit of the Piaui Formation (Neo-carboniferous) and tidal flat deposits from the Pedra de Fogo Formation (Permian), which arises in a large outcrops located between Floriano and Teresina (Piau?), are present. The second area, located at the National Park of Sete Cidades, also at the Piau?, presents rocks from the Cabe?as Formation deposited in fluvial-deltaic systems during the Late Devonian. From the data of the adapted VOMs it was possible to identify lines, surfaces and 3D geometry, and therefore, quantify the geometry of interest. Among the found parameterization values, a table containing the thickness and width, obtained in canal and lobes deposits at the outcrop Pared?o and Biblioteca were the more relevant ones. In fact, this table can be used as an input for stochastic simulation of reservoirs. An example of the direct use of such table and their predicted radargrams was the identification of the bounding surface at the aeolian sites from the Piau? Formation. In spite of such radargrams supply only bi-dimensional data, the acquired lines followed of a mesh profile were used to add a third dimension to the imaging of the internal geometry. This phenomenon appears to be valid for all studied outcrops. As a conclusion, the tool here presented can became a new methodology in which the advantages of the digital imaging acquired from the Laser Scanner (precision, accuracy and speed of acquisition) were combined with the Total Station procedure (precision) using the classical digital photomosaic technique / Neste trabalho s?o apresentados os procedimentos metodol?gicos necess?rios para realizar o imageamento digital 3D da geometria externa e interna de afloramentos an?logos a reservat?rios, e elaborar seus Modelos Virtuais de Afloramentos (MVA). Para imagear a geometria externa foram utilizados o Laser Scanner, o GPS Geod?sico e a Esta??o Total, enquanto que para imagear a geometria interna foi utilizado o GPR. Nos MVA elaborados foram acrescidas ainda as informa??es geol?gicas e as obtidas nas perfilagens com raios gama e de permeabilidade. Como estudo de caso, para exemplificar os procedimentos metodol?gicos propostos, foram escolhidos dois conjuntos de afloramentos na borda leste da Bacia do Parna?ba. Na primeira ?rea ocorrem rochas de origem e?lica da Forma??o Piau? (Neocarbon?fero) e plan?cie de mar? da Forma??o Pedra de Fogo (Permiano), que afloram em um amplo corte de estrada, situado entre Floriano e Teresina (Piau?). A segunda ?rea, situada no Parque Nacional de Sete Cidades, tamb?m no Piau?, envolve rochas da Forma??o Cabe?as depositadas em sistemas fl?vio-deltaicos, durante o Neodevoniano. Com os MVA elaborados foi poss?vel identificar, linhas, superf?cies e geometrias 3D e, assim, quantificar as geometrias de interesse. Dentre as parametriza??es mais relevantes, ressaltam-se a tabela com valores de espessura e largura, obtidas em dep?sitos de canais e em lobos, nos afloramentos Pared?o e Biblioteca. Esta tabela pode ser utilizada como entrada (input) para simula??o estoc?stica de reservat?rios. Um exemplo da aplica??o direta dos radargramas interpretados foi a identifica??o de superf?cies limitantes, em dep?sitos e?licos, da Forma??o Piau?. Apesar dos radargramas oferecerem apenas dados bidimensionais, a aquisi??o de linhas distribu?das segundo uma malha acrescentou a terceira dimens?o ao imageamento das geometrias internas em todos os afloramentos estudados. ? ainda proposta uma nova metodologia que busca conciliar as vantagens obtidas com o imageamento digital com Laser Scanner (precis?o, acur?cia e velocidade de aquisi??o) e a Esta??o Total (precis?o), com o uso cl?ssico de fotomosaicos digitais

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