• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 7
  • 3
  • 1
  • 1
  • Tagged with
  • 14
  • 4
  • 4
  • 3
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 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

Estudo evolutivo do sistema morfoclimático e morfotectônico da bacia do Rio Verde (MG), sudeste do Brasil

Marques Neto, Roberto 10 December 2012 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2018-09-04T12:27:18Z No. of bitstreams: 1 robertomarquesneto.pdf: 22258778 bytes, checksum: b0d66c273cebfa0bbd19b5eabdbcdf4c (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-09-04T13:19:16Z (GMT) No. of bitstreams: 1 robertomarquesneto.pdf: 22258778 bytes, checksum: b0d66c273cebfa0bbd19b5eabdbcdf4c (MD5) / Made available in DSpace on 2018-09-04T13:19:16Z (GMT). No. of bitstreams: 1 robertomarquesneto.pdf: 22258778 bytes, checksum: b0d66c273cebfa0bbd19b5eabdbcdf4c (MD5) Previous issue date: 2012-12-10 / PROQUALI (UFJF) / A bacia do Rio Verde drena uma área de 6.893 km2 na parte meridional do estado de Minas Gerais, em terrenos pertencentes a Serra da Mantiqueira e ao Planalto do Alto Rio Grande. A diversidade paisagística existente em seu perímetro sinaliza para a interferência mútua entre efeitos climáticos e tectônicos atuando na evolução do relevo, que vem dando aporte a diferentes modalidades de uso da terra ao longo da história, o que repercute em diferentes quadros morfodinâmicos. Encerra-se, dessa forma, como objetivo central da presente tese perpetrar um estudo do sistema morfoclimático e morfotectônico da bacia de drenagem em questão mediante uma perspectiva sistêmica, tomando como pressuposto que a verificação integrada dos agentes endógenos e exógenos é conduta necessária para uma interpretação suficientemente abrangente da evolução morfológica da área. Em caráter mais específico, também é tomado como objetivo averiguar as conexões estabelecidas com a dimensão antropogênica através das diferentes formas de uso da terra e alterações ambientais associadas, que se integra à evolução natural da paisagem na conformação de diferentes geossistemas. O estudo das superfícies geomorfológicas subsidiou a compreensão da evolução do relevo e sua compartimentação, procurando-se interpretar os significados climáticos e tectônicos definidores do atual posicionamento das superfícies geomórficas e suas possíveis correlações. No tocante às coberturas superficiais, maior ênfase foi dada aos depósitos fluviais existentes na bacia do Rio Verde, que foram abordados sob o prisma da aloestratigrafia, de grande valia para o estudo de depósitos quaternários. Foi definida uma aloformação neoquaternária correspondente às planícies aluviais atualmente ativas do Rio Verde e principais afluentes, que foi designada como Aloformação Rio Verde, edificada fundamentalmente por sucessões de acreção horizontal e transbordamentos, conformando depósitos datados entre 600 e 1200 anos. A tectônica ativa que também figura como componente fundamental na evolução do relevo regional foi estudada mediante a execução de procedimentos de análise estrutural e interpretação das evidências no relevo e na drenagem de efeitos deformacionais recentes (neotectônicos), e que sobejam na área de estudo na forma de capturas fluviais, deflexão e migração de canais, encaixamento e retilinidade abusiva da drenagem, soerguimento de planícies de inundação, deslocamento de cristas, falhamentos atingindo depósitos recentes, entre outros. Como subsídio ao conjunto de procedimentos acionados para análise geomorfológica e estrutural, foram empreendidas datações absolutas de sedimentos pelo método da Luminescência Opticamente Estimulada (LOE), que auxiliou de forma auspiciosa as interpretações de cunho morfoclimático e morfotectônico. Foram datados depósitos de planícies aluviais soerguidas, o que acusou uma tectônica ativa em idades essencialmente neoquaternárias, compreendidas entre dois e 55 mil anos. Os resultados obtidos a partir do estudo da evolução natural do relevo foram tratados em suas conexões com a dimensão antrópica, integrados em conformidade com a abordagem geossistêmica. Tal leitura concebeu cerca de trinta unidades de mapeamento definidas a partir do relevo, variável fundamental na definição de unidades de paisagem em áreas de topografia movimentada e submetida a uma tectônica ativa, juntamente com o padrão tectônico e estrutural, a textura das coberturas superficiais, a vegetação e o uso da terra. Cada uma dessas unidades constituem classes de fácies discernidas em trinta unidades de mapeamento que se agrupam em um nível superior que, interpretados num sistema bilateral de classificação, correspondem a geomas/macrogeócoros. De forma inequívoca, a evolução natural do relevo pode ser integrada à dimensão antropogênica em uma perspectiva sistêmica, cujo resultado final consubstancia unidades de mapeamento que são reflexos de tais conexões. O caráter integrado de sua definição, exaltando as potencialidades e restrições do meio, podem subsidiar de forma direta o planejamento ambiental e a gestão do território. / Rio Verde's basin drains an 6.893 km2 in the meridional part of Minas Gerais State, in lands that belong to Serra da Mantiqueira and to Planalto do Alto Rio Grande. The paisagistic diversity in their perimeter singns to the mutual interference among climatic and tectonic efects acting in the reflief evolution, which supports different modalities in land use throughout History, deflecting in different morphodynamic pictures. Therefore, as principal aim of this thesis the study of the morphoclimatic and morphotectonic systems of the drainage basin in question supported by a systemic persperctive, taking as pressuposition that the integrated verification of the endogenous and exogenous agents is a necessary conduct towards an intepretation suficiently extensive of morphologic evolution in the area. In a more specific matter, it is also taken as an aim inquire the established conections to the anthopogenic dimension through the different ways of use of the land and associated ambiental alterations, which integrates to the natural evolution of the landscape conforming to different geossystems. The study of the geomorphologic surfaces has served as primordial basis to the comprehension of the refief's evolution and its compartimentation, objecting to interpret the climatic and tectonic significates that define the actual position of geomorphic surfaces and their possible correlation. Referring to superficial coverage, closer emphasis was given to existent fluvial deposites in the Rio Verde's basin, approached under an aloestratigraphic prisma, of great value to the study of quaternary deposites. It has been defined a neoquaternary aloformation which correponds to the currently active alluvial flat lands in Rio Verde and in its main affluents, designed as Rio Verde Aloformation, mainly built by a series of horizontal accretion and overflows, shaping deposites dated between 600 and 1200 years. The active tectonic thar also figures as fundamental component in the regional relief's evolution has been studied through the execution of structural analysis procedures and interpretation of recent (neotectonic) deforming effects evidencies in the relief as well as in the drainage, that abound in the studied area in the form of fluvial captures, deflection e migration of streams, fitting and abusive rectlinearity of the drainage, elevation of flood flat lands, crest displacement, failures achieving recent deposites, among other things. As subsidy to the procedures actuated for the geomorpholic and structural analysis, absolute sediment datings were driven by the Optically Stimulated Luminescence (OSL) method, which assisted in an auspicous ways the interpretation in the morphoclimatic and morphotectonic take. Deposites of elevated alluvial flat lands have benn dated, that accused an active tectonic in essecially neoquartenary ages, comprehended between two and twelve thousand years. The results achieved by the study of the relief's natural evolution were treated ins their connections with the anthopic dimension, integrated in conformity with the geossystemic approach. Such view concieved about thirty unities of mapping defined from the relief, fundamental variable in the landscape unities in areas of active topography and submitted to an active tectonic, along with the tectonic and structural pattern, the texture of the superficial coverages, the use of the land and vegetation. Each one of the unities constitute several kinds of facies discerned in thirty mapping unities that group in a superior level that, interpretated under a bilateral classification system, correspond to geoms/macrogeocorics. In an unequivocal way, the relief's natural evolution may be integrated to the anthropogenic dimension in a systemic perspective, in which final results consubstantiate mapping unities that are reflexes of such connection. The integrated charcter of its definition, emphasizing the potentialities and restriction of the environment, can subsidize in a direct way o ambiental planning and the territorry management.
12

Characterisation of some fractured-rock aquifers in Limpopo province, South Africa : review and case study

Dippenaar, Matthys Alois 13 October 2009 (has links)
This dissertation collates all available data from the Department of Water Affairs and Forestry’s (DWAF’s) National Groundwater Database (NGDB), DWAF’s Groundwater Resource Information Project (GRIP) and tests conducted during the progress of this project in order to evaluate Basement aquifers. The project was commenced at the request of the Water Research Commission (WRC), situated in Pretoria, South Africa. The study area (Limpopo and Luvuvhu-Letaba Water Management Areas, WMA1 and WMA2 respectively) is underlain by fractured, crystalline Basement terrain. The influences of structures (i.e. joints, faults and shear zones) and the neotectonic stress conditions were also studied to address the influence on groundwater flow and occurrence. The aim of the project was to address the determination of the aquifer parameters (essentially transmissivity and sustainable yield) in Basement terrane. Pumping test data was used and analysed via the Flow Characteristic Programme (Institute for Groundwater Studies, University of Free State). The methods of Logan (1964), Theis (1935), Cooper-Jacob (1946) and Birsoy-Summers (1980) were applied for comparative purposes. Statistically, all four methods supplied results within the same order of magnitude, with Theis and Cooper-Jacob correlating extremely well. Results from the Logan and Birsoy-Summers methods correlated very well too, but the T-values calculated via Logan’s method were almost double those obtained from the step-drawdown data analysed via the Birsoy-Summers method. The combined results adhered to a developed model-setting-scenario approach where each borehole can be evaluated based on three parameters. Firstly, the model refers to the potential water-bearing and/or water-barring features. In the study area, it was found that water predominates in the Hout River Shear Zone, and that the neotectonic stress fields have little influence on determining the orientation of favourable water-bearing structures. Geological contacts often resulted in higher yielding boreholes than geological structures. Secondly, the setting refers to the climatic and tectonic setting of the site. This determines the recharge and the orientation of structures. Based on this, supposedly closed structures (due to prevailing neotectonic stress fields) often supplied higher yielding boreholes than the supposedly open structures. Rainfall and climate however had little influence on the results. Finally, the scenario ranks a borehole in terms of high, intermediate or low transmissivity and subsequently potential yield. High T-values typically exceeded 100 m2/d whereas low T-values were generally below 5 m2/d. Significantly low yielding boreholes therefore formed part of the Low T Scenario, and high yielding boreholes of the High T Scenario. Copyright / Dissertation (MSc)--University of Pretoria, 2008. / Geology / unrestricted
13

Neotectonics And Seismicity Of The Ankara Region: A Case Study In The Urus Area

Kaplan, Tulin 01 July 2004 (has links) (PDF)
Study area, the UruS province, is located 70 km WNW of city of Ankara. Major settlements in the study area are two counties, UruS and G&uuml / d&uuml / l / and there are a number of villages, such as, from W to E, Macun, Yogunpelit, Kabaca, &Uuml / regil, &Ouml / zk&ouml / y, Tahtaci&ouml / rencik, Kirkkavak, Kavak&ouml / z&uuml / , Kayi and Karaca&ouml / ren. The study area is 189 km2 in size and included in 1/25000-scaled topographic quadrangles of H28a3, a4, d1 and d2. The G&uuml / d&uuml / l- UruS section of the &Ccedil / eltik&ccedil / i morphotectonic depression (&Ccedil / eltik&ccedil / i Basin) drained by the Antecedent Kirmir River and its second-order drainage system was first mapped in detail in the present study, and faults determining northern margin of the &Ccedil / eltik&ccedil / i depression were named as the UruS fault set comprising the SW part of the &Ccedil / eltik&ccedil / i Fault Zone / and the mechanism of the master fault of the UruS fault set was determined as left lateral oblique-slip fault with reverse component by the morphologic markers such as the deformed drainage system and pressure ridges. This was also supported by the fault plane solutions of the 2000.08.22 UruS earthquake. Three fault plane solutions, of which two of them for the 2000.08.22 UruS earthquake, and one of them for the 2003.02.27 &Ccedil / amlidere earthquake, were done to determine nature of the source. Ground material underlying the city of Ankara were divided into three categories: (a) well-lithified basement rocks, (b) Pliocene fluvio-lacustrine v sedimentary sequence, and (c) unconsolidated terrace and alluvial sediments of Quaternary age. Quaternary unconsolidated sediments are densely populated in Ankara. These sediments are fine-grained and have a maximum thickness of 200 m or more. Inside these sediments, static ground water level is very close (as on average: 6 m) to ground surface. These conditions are quite suitable for liquefaction of these unconsolidated alluvial sediments. In addition, basement rocks are full of zone of weakness. Even if, the city of Ankara is characterized by the shallow focus and small earthquakes (M&amp / #8804 / 5), it is open to the risk of large earthquakes to be sourced from the North Anatolian Fault System and the Seyfe Fault Zone located 110 km and 80 km, respectively, owing the ground material conditions beneath the city of Ankara. This point has to be taken out in constructions and site selection solution.
14

Express?o em superf?cie do sistema de falhas Po?o Verde-cara?bas, Bacia Potiguar

Santos, Rafael Duarte 28 February 2011 (has links)
Made available in DSpace on 2015-03-13T17:08:30Z (GMT). No. of bitstreams: 1 RafaelDS_DISSERT.pdf: 4082190 bytes, checksum: dabe52ff23738bb49110e1bc03f1b41a (MD5) Previous issue date: 2011-02-28 / The structural knowledge of the western portion of the Potiguar Basin is still in its infancy, especially these related to NW-trending fault systems. This paper analyzes the Po?o Verde-Cara?bas Fault System, which was initially recognized in subsurface. The activities involved in this study correspond to remote-sensing analysis and, in particular, to the geometric and kinematic analysis of post-rift sequences of the basin. In addition, the study aimed to determine the stress fields operating in the area. The studies were carried out in an area of 1,000 km?, located in the western portion of Potiguar Basin along the Po?o Verde-Cara?bas Fault System, Rio Grande do Norte State. The remote sensing imagery indicates a predominance of NW-SE-trending lineaments, consistent with the fault system under study, followed by the NE-SW, N-S and E-W directions. The tectonic structures mapped were analyzed only in outcrops of the Janda?ra Formantion. They are joints (filled or not) in all directions, but with predominance of the NW-trending joints. Faults are usually N-S-trending normal faults and NW-SE and NE-SW-trending strike-slip faults. Geodynamic analysis identified two tectonic stress fields: the first field, "Field 1" is represented by an N-S-trending horizontal compression and E-W-trending horizontal extension. This field affected the Potiguar Basin at least until the Miocene. The second field, "Field 2", is represented by an E-W-trending horizontal compression and N-S-trending horizontal extension. This is the present-day stress field and has affected the Potiguar basin since the Pliocene / O conhecimento estrutural da por??o oeste da Bacia Potiguar ainda ? incipiente, principalmente aquele relacionado aos sistemas de falhas NW-SE. Esta disserta??o analisa o Sistema de Falhas Po?o Verde-Cara?bas, onde foi inicialmente individualizado em subsuperf?cie. As atividades realizadas inerentes a este estudo correspondem ? an?lise de sensoriamento remoto e principalmente ? an?lise geom?trica e cinem?tica, da seq??ncia p?s-rifte da bacia. Al?m disso, o estudo teve como objetivo determinar os campos de tens?o que operam na ?rea. Os estudos foram realizados numa ?rea de 1.000 km?, localizada na por??o oeste da Bacia Potiguar, ao longo do Sistema de Falhas Po?o Verde-Cara?bas, estado do Rio Grande do Norte. As imagens de sensoriamento remoto indicam uma predomin?ncia de lineamentos orientados na dire??o NW-SE, consistente com o sistema de falha em estudo, seguido das dire??es NE-SW, N-S e E-W. As estruturas tect?nicas mapeadas foram analisadas somente em afloramentos da Forma??o Janda?ra. Eles s?o juntas (preenchidas ou n?o) em todas as dire??es com predomin?ncia para o trend NW-SE. Falhas normais de dire??o aproximada N-S, falhas transcorrentes nas dire??es NW-SE e NE-SW. A an?lise geodin?mica identificou dois campos de tens?es. O primeiro campo, Campo 1 , ? representado por uma compress?o N-S horizontal e distens?o E-W. Este campo atuou na Bacia Potiguar pelo menos at? o Mioceno. O segundo campo, Campo 2 ? representado por uma compress?o horizontal E-W e distens?o horizontal N-S. Este ? o atual campo de tens?es e tem afetado a Bacia Potiguar desde o Plioceno

Page generated in 0.0552 seconds