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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.
41

Geophysical constraints on the stratigraphy, structure and tectonic evolution of the Late Devonian/Carboniferous Moncton Subbasin, New Brunswick /

Nickerson, William A. January 1994 (has links)
Thesis (Ph.D.)--Memorial University of Newfoundland. / Typescript. Restricted until November 1995. Bibliography: leaves [306]-329. Also available online.
42

Tectonics and basin deformation in the Cabot Strait Area and implications for the late Paleozoic development of the Appalacians in the St. Lawrence Promontory /

Langdon, George S., January 1996 (has links)
Thesis (Ph.D.)--Memorial University of Newfoundland, 1996. / Restricted until November 1997. Bibliography: leaves 228-255. Also available online.
43

Gravity analyses for the crustal structure and subglacial geology of West Antarctica, particularly beneath Thwaites Glacier

Diehl, Theresa Marie, January 1900 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.
44

Paleossolos da Formação Marília no município de Campina Verde, oeste de Minas Gerais / Marilia Formation paleosols of the city of Campina Verde, West of Minas Gerais

Pereira, Camila Tavares, 1988- 25 August 2018 (has links)
Orientador: Alessandro Batezelli / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociências / Made available in DSpace on 2018-08-25T01:50:06Z (GMT). No. of bitstreams: 1 Pereira_CamilaTavares_M.pdf: 6719830 bytes, checksum: c010edfeb787dd0ffb56ed12b5a56676 (MD5) Previous issue date: 2014 / Resumo: A Formação Marília, que aflora no sudeste do Brasil, é uma sucessão sedimentar caracterizada por estratos sedimentares alternados com paleossolos. As feições pedogenéticas podem ser relacionadas com os fatores climáticos e são utilizadas como ferramenta na interpretação de paleoambientes. Através da descrição macro e microscópica, associada a análise mineralógica e fluorescência de raios-X, foram identificados e caracterizados 20 de perfis de paleossolos da Formação Marília, Maastrichtiano da Bacia Bauru. A intercalação de horizontes C, Ck, Bt, Btk e Gley, possibilitaram a elaboração de um modelo de evolução paleoambiental, onde os dados geoquímicas permitiram tecer considerações paleoclimáticas. As mudanças nos processos de formação destes paleossolos foram impulsionadas principalmente pelas variações de umidade disponível. As estimativas de paleoprecipitação (MAP) obtidas por meio do CIA-K em horizontes Bt e Btk, indicam que a pluviosidade variou de 20-1000 mm/ano. Estas condições climáticas contrastantes resultaram na sobreposição de perfis distintos, sugerindo oscilação entre condições áridas a semiáridas. Estes resultados contribuem para um melhor entendimento paleoambiental do Cretáceo Tardio para a porção sudeste brasileira / Abstract: The Marília Formation is the Maastrichtian sequence of the Bauru Basin and crops out in southeastern Brazil. It is a sedimentary succession characterized by alternating sedimentary strata and paleosols. The pedogenic features can be related to climatic factors and are used as a tool in the interpretation of paleoenvironments. By means of a macro- and microscopic description, associated with mineralogical and x-ray fluorescence analyses, twenty paleosol sections were identified and characterized in the Marília Formation. The characterization of C, Ck, Bt, Btk and Gley horizons and the corresponding geochemical data helped define a paleoenvironmental evolutionary model and make some paleoclimatic considerations. Changes in the processes of formation of these paleosols were mainly triggered by moisture variations. Paleoprecipitation estimates (MAP) obtained by means of CIA-K in Bt and Btk horizons indicate that precipitation varied 20-1000 mm/year. These contrasting climatic conditions caused overlapping of distinct profiles, suggesting oscillation between arid to semi-arid conditions. These results contribute to a better understanding of the Upper Cretaceous paleoenvironment in southeastern Brazil / Mestrado / Geologia e Recursos Naturais / Mestra em Geociências
45

Caracterização de reservatórios fluviais da Bacia de Taubaté, SP / Fluvial reservoir characterization of Taubaté Basin, SP

Carvalho, Ancilla Maria Almeida de, 1980- 19 August 2018 (has links)
Orientador: Alexandre Campane Vidal / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociências / Made available in DSpace on 2018-08-19T03:20:14Z (GMT). No. of bitstreams: 1 Carvalho_AncillaMariaAlmeidade_M.pdf: 3762992 bytes, checksum: 2ca7884e4a41caafd5d67ba3965bf9dc (MD5) Previous issue date: 2011 / Resumo: A Bacia de Taubaté, localizada na porção leste do estado de São Paulo, ocupa uma área aproximada de 2400 km², estendendo-se ao longo do Vale do Rio Paraíba, desde Jacareí até a cidade de Cruzeiro. Posicionada no segmento central do Rifte Continental do Sudeste do Brasil, seu arcabouço estrutural é formado por semi-grábens, separados por zonas de transferência ou acomodação, com depocentros invertidos sendo caracterizada pela heterogeneidade, herança geológica da tectônica rifte que compartimentou a bacia e condicionou a sedimentação de depósitos de leques aluviais associados a planícies fluviais e sedimentos lacustres. Os sedimentos da bacia formam uma das principais fontes de exploração de água do Estado de São Paulo, fornecendo alta densidade de informação para estudo em subsuperfície, como dados de poços tubulares profundos, perfis geofísicos e seções sísmicas. A revisão de dados disponíveis na bibliografia e nos órgãos destinados ao abastecimento público permitiu a construção de uma base de dados sólida para a caracterização do embasamento da bacia e dos reservatórios fluviais que a compõem. O foco deste trabalho foi a construção de um modelo geológico tridimensional do arcabouço estrutural da bacia, da distribuição de fácies sedimentares e propriedades petrofísicas, utilizando para isso métodos geoestatísticos. A delimitação do embasamento foi realizada por meio da interpolação de dados sísmicos, gravimétricos e de poços tubulares profundos realçando a presença de quatro depocentros principais na bacia. A definição das fácies sedimentares foi realizada por meio de métodos matemáticos, a partir de perfis geofísicos, e seu resultado permitiu a correlação de poços em determinada porção da bacia gerando nessa área uma melhor caracterização da distribuição dos reservatórios. Por meio de simulação estocástica foram gerados diversos cenários da distribuição das fácies sedimentares e da porosidade de um bloco situado no Compartimento São José dos Campos, sudoeste da bacia, permitindo também a obtenção de um modelo de conectividade dos aqüíferos e volume poroso do bloco estudado / Abstract: The Taubaté Basin, located in the southeastern portion of the São Paulo state, encompasses an area of approximately 2400 km², stretching along the Paraíba River Valley, from Jacareí to the Cruzeiro city. Positioned in the central segment of the Continental Rift of Southeastern Brazil, its framework is formed by half-grabens, separated by transfer zones or accommodation with reversed depocenters been characterized by heterogeneity, geological heritage of the tectonic rift that partitioned the basin and conditioned the sedimentation of alluvial fan deposits associated with the plain aluvial and lacustrine sediments. The sediments of the basin form a major source of water exploration in the São Paulo State, providing high density of information to study the subsurface, as data from deep wells, geophysical and seismic profiles. A review of available data in the literature and organs intended for public supply has allowed the construction of a solid database for the basement characterization of the basin and the reservoirs that comprise it. The focus of this work was the construction of a three-dimensional geological model of the structural framework of the basin, the distribution of sedimentary facies and petrophysical properties using geostatistical methods. The delimitation of the basement was done through the interpolation of seismic data, gravity and information from deep wells highlighting the presence of four main depocentros basin. The definition of sedimentary facies was performed by mathematical methods, based on geophysical profiles, and the result allowed the correlation of wells in a certain portion of the basin, creating a better characterization of the reservoirs distribution in this area. Through stochastic simulation various scenarios were generated of sedimentary facies distribution and porosity of a block located in Sao Jose dos Campos Compartment, southwest of the basin, allowing the obtaining of a connectivity model of aquifers and porous volume of the block studied / Mestrado / Geologia e Recursos Naturais / Mestre em Geociências
46

The nature of the western margin of the Witwatersrand Basin

Van der Merwe, Roelof 07 October 2014 (has links)
D.Phil. (Geology) / The tectonic evolution of the "western margin" of the Witwatersrand Basin is examined and indications are that it has undergone a long and complex history. In order to examine the nature of Witwatersrand-age structures, structures in both pre- and post-Witwatersrand sequences are also examined. Rocks of the ±3074 Ma Dominion Group were subjected to a tectono-metamorphic event prior to the deposition of Witwatersrand strata on an angular unconformity. An oligomictic conglomerate is sporadically developed at the base of the Witwatersrand Supergroup. PreVentersdorp structures in Witwatersrand strata are developed in two distinct trends, north-south and northeast-southwest. The relationship between the two directions of folds and thrust faults are best explained within a regional, sinistral transpressive shear couple; the north-south faults are sinistral strike-slip faults and the northeast-southwest trending folds and thrust faults are secondary structures associated with the strikeslip faults. The implications of this model are that Witwatersrand sedimentation was probably controlled by lateral movements on north-south trending faults and not by thrust faults in a foreland system as suggested by the most recent models of Witwatersrand basin development. Post-Witwatersrand deformation is complex. Southeastward verging, pre-Ventersdorp, thrust faults were reactivated as normal faults during Platberg times and the resultant half-grabens were infilled by conglomerates of the Kameeldoorns Formation. Later deformational events include eastward verging post-Ventersdorp thrust faults and post-Transvaal normal and strike-slip faults. It can be demonstrated that the majority of this later fault movements took place along pre-existing fault planes and therefore tectonic inversion is a fundamental process in the evolution of the Witwatersrand Basin. Clearly therefore, the present distribution of Witwatersrand strata does not reflect the original basin geometry, it is the result of several periods of basin inversion and no basin margins can be defined.
47

The geology of the Godwan Basin, Eastern Transvaal

Myers, R.E. 05 August 2014 (has links)
M.Sc. (Geology) / Please refer to full text to view abstract
48

Constraining the age of the Noumea Basin : isotope ages and paleomagnetic data from New Caledonia

Orton, Kristopher T. 21 July 2012 (has links)
Geological evidence suggests large-scale continental extension during the breakup of the eastern Gondwana margin was the predominant force controlling rifting of New Caledonia from the eastern Gondwana margin and formation of the Tasman Sea in the Late Cretaceous. Tectonic models suggest slab-rollback forces elongated and thinned the crustal lithosphere detaching crustal fragments from the Gondwana margin. Current tectonic models lack detailed timing and placement of this crustal detachment with respect to New Caledonia based on lack of evidence (rocks). An isotope and paleomagnetic study was carried out on a bi-modal assemblage of volcanic rock exposed on the southwest side of New Caledonia in the Nouméa Basin. U/Pb isotope ages of zircon grains found within siliceous volcanic rock in the Nouméa Basin provide temporal evidence that volcanism persisted both before and after the breakup of the eastern Gondwana Continent (100-90 Ma) in the Late Cretaceous. Four isotope ages >97 Ma and a series (11 samples) ranging from 91-76 Ma constrain the siliceous volcanism of the Nouméa Basin to the Late Cretaceous. A paleomagnetic inquiry utilizing statistics of both McFadden/Reid and Fisher carried out on 16 Nouméa Basin siliceous and mafic in situ formations place the oldest volcanic units found within the Nouméa Basin at 650 S latitude as New Caledonia began to separate from Gondwana (~100 Ma). The data suggests a well-developed arc signature in the region, which persisted for at least 15 Ma in the Late Cretaceous. Compared to current tectonic models of the southwest Pacific Region from the Late Cretaceous to Eocene, our data suggests New Caledonia was further south on the eastern Gondwana supercontinent prior to rifting in the Late Cretaceous than current models. / Geologic background -- Tectonic setting -- Methods -- Sampling -- Results -- Discussion. / Department of Geological Sciences
49

Comparaison de la composition des roches métasédimentaires archéennes dans six bassins de la province du Supérieur : une étude géochimique et statistique /

Doyon, Julie, January 2004 (has links)
Mémoire (M.Sc.T.) -- Université du Québec à Chicoutimi, 2004. / Bibliogr.: f. [149]-154. Document électronique également accessible en format PDF. CaQCU
50

Qualidade das aguas na bacia do Ribeirão Pinheiros : uma proposta de recuperação / Water quality in the Ribeirão Pinheiros Basin, a proposal of recovery

Isenburg, Adriana Angelica Rosa Vahteric 31 August 2005 (has links)
Orientador: Sueli Yoshinaga Pereira / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociencias / Made available in DSpace on 2018-08-05T07:43:31Z (GMT). No. of bitstreams: 1 Isenburg_AdrianaAngelicaRosaVahteric_M.pdf: 9802147 bytes, checksum: 3d39ebfc1ccea41250d0a2f3baefb0a3 (MD5) Previous issue date: 2005 / Resumo: A gestão dos recursos hídricos é hoje uma questão preocupante e polêmica. À medida que se verifica um intenso crescimento populacional, com uma exploração hídrica descontrolada, constata-se a evolução da degradação ambiental, com sérios prejuízos para os corpos d'água. A política implantada sugere que somente com a construção de estações de tratamento de esgoto, poderá ser revertido o quadro de poluição exacerbada dos rios. Entretanto, pretende-se com este trabalho demonstrar que apenas esta medida não proporcionará a recuperação adequada dos rios. São necessárias outras ações para que a qualidade das águas seja restabelecida e, assim, permitir sua utilização harmônica, seja para consumo humano, seja para o cultivo de plantas, dessedentação de animais e lazer. O estudo é desenvolvido em uma importante microbacia situada a montante da principal captação de água do município de Campinas e avalia sua influência na degradação da qualidade da água no rio Atibaia. A microbacia em questão, denominada Microbacia do ribeirão Pinheiros, é caracterizada pela existência de um alto adensamento urbano, resultante da conurbação existente entre os municípios de Campinas, Valinhos e Vinhedo. Com a entrada em operação das estações de tratamento de esgoto nos municípios de Campinas e de Vinhedo é possível avaliar a evolução dos parâmetros de qualidade da água ao longo do principal rio que recebe os efluentes destas três cidades. O estudo analisa também o reflexo dos novos procedimentos operacionais estabelecidos quando da outorga do Sistema Cantareira para o abastecimento da cidade de São Paulo, que possibilitou uma adequação da vazão disponibilizada para o rio Atibaia. A partir da análise dos dados de qualidade e das informações existentes sobre a ocupação das terras é desenvolvido um diagnóstico ambiental da microbacia, destacando a importância de ações de recuperação ambiental, respeitando as áreas de preservação, bem como de implementação de projetos urbanísticos estruturados e de programas de conscientização, desta forma, buscando a melhoria da qualidade de vida da população / Abstract: The hydric resources management is nowadays a concerning and controversial subject. As an intensive population growth is verified and an uncontrolled hydric exploration, the evolution of the environmental degradation is noticed with serious harms for the rivers. The implemented policy suggests that only with the construction of sewage treatment plants must reverse the exacerbated rivers pollution frame. However, in this work we intend to demonstrate that this measure is not enough to provide the appropriate recovery of the rivers. There will be other actions to reestablish the water quality and so, it will allow its harmonic usage such as human consumption, or for plants growth, to quench the animals' thirst and leisure. This study is developed in an important microbasin located upstream of the main water catchment of Campinas City and it is evaluated its influence in the water quality degradation in the Atibaia River. The microbasin in study, called Ribeirão Pinheiros Microbasin, is characterized by the existence of a high urban densification, concerning the existent conurbation among Campinas, Valinhos and Vinhedo municipalities. When the sewage treatment plants started their operation in Campinas and Vinhedo cities it was possible to evaluate the improvement of water quality parameters in the main river, which received the effluents from these three cities. The study also analyzed the reflex of the new operational proceedings established when it got the Cantareira System Granting to supply São Paulo City that enabled a flow adequacy available to Atibaia River. Apart from the quality data analyze and the existent information about the land occupation it was developed the microbasin environmental diagnosis, detaching the importance of the environmental recovery actions, respecting the preservation areas as well as the structured urbanistic projects implementation and cognizants programs and this way trying to improve the quality of life of the population / Mestrado / Geologia e Recursos Naturais / Mestre em Geociências

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