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Indicadores do n?vel relativo do mar e evolu??o costeira durante o holoceno tardio no litoral oeste do Cear?, NE do BrasilVasconcelos, David Lino 26 February 2014 (has links)
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Previous issue date: 2014-02-26 / Na regi?o litor?nea do Cear?, entre os munic?pios de Acara? e Itapipoca, foram
identificados treze s?tios contendo indicadores do n?vel relativo do mar, sendo seis
destes datados por luminesc?ncia opticamente estimulada (LOE) e radiocarbono. As
idades obtidas suportam que foram formadas praias progradantes na ?rea de estudo. Na
parte oriental, ocorrem praias em dep?sitos de plan?cie costeira, enquanto que um
sistema laguna/barreira com paleomanguezais ocorre na parte ocidental da ?rea de
estudo. Em ambos os casos os dep?sitos costeiros progradam de leste para oeste. Foram
identificados n?veis de mar mais alto que o atual entre: (a) 3.110-2.830 anos cal. AP; (b)
1.830 anos AP (LOE) - 1.490 anos cal. AP; (c) entre 1.240-1.060 anos cal. AP; (d) 845-
715 anos AP (LOE). Desde ent?o o n?vel do mar sofreu um abaixamento at? o n?vel
atual. As varia??es do n?vel do mar s?o interpretadas como respostas a altera??es no
padr?o de circula??o marinha e n?o exclu?mos poss?veis perturba??es tect?nicas na
bacia da margem continental. Os indicadores do n?vel relativo do mar para litoral oeste
do Cear? apresentam-se diferente das outras curvas constru?das no litoral do nordeste,
sugerindo que os fatores locais citados acima contribu?ram para flutua??es do n?vel do
mar. / In the coastal region of Cear?, between the municipalities of Acara? and Itapipoca,
thirteen sites were identified containing indicators of relative sea level, six of these
being dated by optically stimulated luminescence (OSL) and radiocarbon. Ages
obtained supports that were formed prograding beaches in the study area. In the eastern
portion, beaches in coastal plain deposits occur while a system lagoon/barrier
paleomangrove occurs in the western portion of the study area. In both cases the coastal
deposits prograde from east to west. Higher sea levels were identified between the
current: (a) 3.110-2.830 cal. yr. BP; (b) 1.830 yr. BP (OSL) - 1.490 cal. yr. BP; (c)
between 1.240-1.060 cal. yr. BP; (d) 845-715 yr. BP (OSL). Since then the sea level
suffered by lowering the current level. Variations in sea level are interpreted as
responses to changes in the pattern of marine circulation and do not exclude possible
tectonic disturbances in the basin of the continental margin. The indicators of relative
sea level west coast of Cear? present differently from other curves constructed in the
coastal northeast, suggesting that local factors mentioned above contributed to sea level
fluctuations.
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Caracteriza??o da din?mica ambiental da regi?o costeira do munic?pio de Galinhos, litoral setentrional do Rio Grande do NorteLima, Zuleide Maria Carvalho 10 March 2004 (has links)
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Previous issue date: 2004-03-10 / This doctorate thesis concerning on the Characterization of the Environmental Dynamics of the Coastal Area of the Municipal district of Galinhos, Septentrional Coast of Rio Grande do Norte State, is located in the influence area of the Guamar? Petroliferous Pole, having as general objective the understanding of the active coastal dynamics in the region of Galinhos, whose specific objectives were: To study the variation of the coast line in the decades of 1954, 1967,1988, 1996, 2000, from remote sensing products; To elucidate the hypothesis of the region of Galinhos to have been an old system of islands barriers, using as basic tool the penetration radar in the soil - GPR; To monitor and to characterize the coastal dynamics of the study area starting from monthly data of beach profiles, sedimentological analysis, hydrodynamic data and environmental characterization data; which were used to feed the database of the N-NE network of Environmental Monitoring of Areas under Influence of the Petroliferous Industry;(REDE05/FINEP/CNPq/CTPETRO/ PETROBRAS). This research is justified, of the environmental point of view, by involving the mangrove ecosystem considered one of the most delicated environments of the State. From the viewpoint of the petroleum exploration, the systems of islands barriers are favorable for hydrocarbons reservoirs and, consequently important targets to the oil and gas industry, becoming this region attractive in comparison with similar lithified environments. With the results of the variability study in the position of the coast line in the Municipal district of Galinhos/RN from the analysis of remote sensing images, it was possible to investigate the changes in the coast line in temporal scale; the use of directional filters allowed to emphasize linings in the direction NE and to identify submerged features such as sandwaves. The use of GPR enabled the confirmation of paleochannels existence and thus confirmed the hypothesis that the Galinhos spit was formed from an old system of islands barriers. The results of the granulometric analyses indicated that in the summer period the
sediments in the profiles A and B in the foreshore portion were classified with the granulometry of sand with scattered gravel and in the shoreface were constituted by sand, but in the winter period these same morphologic compartments were constituted by sand with sparse gravel and siltic sand respectively. In the profile C, in the summer and in the winter, the shoreface and foreshore compartments presented predominantly constituted by sand with sparse gravel. The hydrodynamic results showed that the largest wave heights were registered in the month of February (62 cm) and the highest period of 1,00 m/s in the month of May, the sense of the coastal currents was kept among the quadrants SW and NW, and the winds coming from NE were predominant. The analysis of the beach profiles demonstrated that in the profile A, although it had occurred erosion and deposition during the monitored months, the morphology of the referred profile was kept constant. In the profiles B and C, there were abrupt changes in the morphology, during the monitored months, having been identified a cyclic pattern in the features
of the foreshore zone sometimes forming longitudinal sandy bars and in other times forming berm. These results evidenced, therefore, that studies of this nature are of fundamental importance for the coastal zoning, aiming subsidies to the organs managers in the closing of
decisions as for the implantation of enterprises in the area, and for the industry of the petroleum through generation of information that subsidize the implementation and location of petroliferous structures adequate to this environment / Esta tese de doutorado sobre a caracteriza??o da din?mica ambiental da regi?o costeira do munic?pio de Galinhos, Litoral Setentrional do Rio Grande do Norte, acha-se inserida na ?rea de influ?ncia do P?lo Petrol?fero de Guamar?, tendo como objetivo geral o entendimento da din?mica costeira atuante na regi?o de Galinhos, cujos objetivos espec?ficos foram : estudar a varia??o da linha de costa nas d?cadas de 1954, 1967, 1988, 1996 e 2000, a partir de produtos de sensoriamneto remoto; elucidar a hipotese da regi?o de Galinhos ter sido um antigo sisitema de ilhas barreiras, utilizando como ferramneta b?sica o radar de penetra??o no solo - GPR; monitorar e caracterizar a dinamica costeira da ?rea em estudo a partir de dados mensais da perfis praiais, analise sedimentologica, dados hidrodin?micos e dados de caracteriza??o ambiental; este conjunto de dados foram utilizados para alimetar o banco de dados da Rede NNE de monitoramneto ambiental das ?reas sob influ?ncia da industria petrol?fera (REDE05/FINEP/CNPq/CTPERO/PETROBRAS). Esta pesquisa se justifica, do ponto de vista ambiental,
por envolver ecossistemas de alta fragilidade como dunas, praias e manguezais. Do ponto de vista da explora??o do petr?leo, os sistemas de ilhas barreiras s?o prop?cios para reservat?rios de hidrocarbonetos e, por conseguinte, alvos importantes para a ind?stria do petr?leo e g?s tornando
esta regi?o atrativa na compara??o com dep?sitos similares litificados. O estudo da variabilidade na posi??o da linha de costa no Munic?pio de Galinhos/RN a partir da an?lise de imagens de sensores remotos, foi poss?vel investigar as mudan?as na linha de costa em escala temporal; a
utiliza??o de filtros direcionais permitiu enfatizar lineamentos de dire??o NE e identificar fei??es submersas tais como sandwaves. A utiliza??o do GPR possibilitou a comprova??o da exist?ncia de paleocanais confirmando a hip?tese de que o spit de Galinhos foi formado a partir de um antigo sistema de ilhas barreiras. Os resultados das an?lises granulom?tricas indicaram que no per?odo de ver?o os sedimentos nos perfis A e B na por??o de estir?ncio foram classificados como de granulometria areia com cascalho esparso e na antepraia foram constitu?dos por areia, j? no per?odo de inverno estes mesmos compartimentos morfol?gicos apresentaram-se com areia com cascalho esparso e areia siltosa respectivamente No perfil C, tanto no ver?o como no inverno, os compartimentos de estir?ncio e antepraia apresentaram-se predominantemente por areia com cascalho esparso. Os resultados hidrodin?micos mostraram que as maiores alturas de
onda foram registradas no m?s de fevereiro (62 cm) e o maior per?odo de 1,00 m/s no m?s de maio, o sentido das correntes litor?neas se manteve entre os quadrantes SW e NW, e os ventos provenientes de NE foram predominantes. A an?lise dos perfis praiais demonstrou que no perfil A, embora tenha ocorrido tanto eros?o como deposi??o durante os meses monitorados, a morfologia do referido perfil permaneceu constante. Nos perfis B e C, ocorreram mudan?as bruscas na morfologia, durante os meses monitorados, tendo sido identificada uma ciclicidade nas fei??es da zona de estir?ncio ora formando barras arenosas longitudinais ora formando berma. Estes resultados evidenciaram, portanto, que estudos desta natureza s?o de fundamental import?ncia para o zoneamento costeiro, dando subs?dios aos ?rg?os gestores na tomada de decis?es quanto ? implanta??o de empreendimentos na regi?o, e para a ind?stria do petr?leo
atrav?s de gera??o de informa??es que subsidiam a implementa??o de estruturas petrol?feras adequadas ao ambiente estudado
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