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Estudo evolutivo do sistema morfoclimático e morfotectônico da bacia do Rio Verde (MG), sudeste do BrasilMarques Neto, Roberto 10 December 2012 (has links)
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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.
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Characterisation of some fractured-rock aquifers in Limpopo province, South Africa : review and case studyDippenaar, 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
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Neotectonics And Seismicity Of The Ankara Region: A Case Study In The Urus AreaKaplan, 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
Gü / dü / l / and there are a number of villages, such as, from W to E, Macun,
Yogunpelit, Kabaca, Ü / regil, Ö / zkö / y, Tahtaciö / rencik, Kirkkavak, Kavakö / zü / ,
Kayi and Karacaö / ren. The study area is 189 km2 in size and included in
1/25000-scaled topographic quadrangles of H28a3, a4, d1 and d2. The Gü / dü / l-
UruS section of the Ç / eltikç / i morphotectonic depression (Ç / eltikç / 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 Ç / eltikç / i depression were named as the UruS fault set
comprising the SW part of the Ç / eltikç / 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 Ç / 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& / #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.
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Express?o em superf?cie do sistema de falhas Po?o Verde-cara?bas, Bacia PotiguarSantos, Rafael Duarte 28 February 2011 (has links)
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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
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