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Caracteriza??o morfol?gica-sedimentar do vale inciso Apodi-Mossor? e plataforma continental adjacente - Bacia Potiguar OffshoreNogueira, Mary L?cia da Silva 15 August 2014 (has links)
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Previous issue date: 2014-08-15 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico - CNPq / Sistemas de vales incisos t?m sido estudados em diferentes plataformas continentais
incluindo a margem continental Brasileira. O interesse de caracterizar esta fei??o se d? pelas
indica??es que a mesma pode fornecer sobre varia??es do n?vel do mar, assim como a possibilidade
de abrigar quantidades economicamente significativas de hidrocarbonetos em reservat?rios
localizados nos dep?sitos de preenchimento dos vales incisos. A presente tese tem como objetivo
geral caracterizar a morfologia e cobertura sedimentar do vale inciso Apodi-Mossor?, localizado na
plataforma continental Norte do Estado do Rio Grande do Norte, adjacente a cidade de Areia
Branca. A metodologia utilizada incluiu a integra??o de imagens de sat?lite, dados batim?tricos, de
s?smica rasa, sedimentol?gicos e de identifica??o de foramin?feros. Os resultados obtidos indicam
que o vale inciso Apodi-Mossor? ? formado atualmente por dois canais, denominados de canal raso
e canal profundo, que apresentam caracter?sticas morfol?gicas e sedimentol?gicas distintas.
O canal profundo apresenta conex?o com uma das cabe?as do canyon Apodi localizado na ?rea do
Talude. A aquisi??o, processamento e interpreta??o de dados de s?smica rasa possibilitaram o
reconhecimento no fundo e no subfundo marinho de superf?cies deposicionais/erosionais,
discord?ncias e sismof?ceis. A superf?cie erosional mapeada nas se??es de s?smica rasa
possivelmente ? indicativa de uma antiga superf?cie de incis?o do vale inciso, onde a sua forma??o
estaria provavelmente associada ao limite Pleistoceno/Holoceno. Diferentes sismof?ceis foram
identificadas no subfundo e refletem a subida no n?vel do mar com padr?es ora agradacional ora
progradacional. A espessura dos sedimentos sobre esta superf?cie foi estimada em um m?ximo de
22 m de espessura na por??o central do vale inciso. Estatisticamente h? diferen?as entre a
plataforma continental adjacente e os canais raso e profundo quanto ao conte?do de carbonato de
c?lcio, mat?ria org?nica, areia e lama, com exce??o para granulometria cascalho. A an?lise de
foramin?feros vivos e mortos mostrou a presen?a de cinquenta esp?cies distribu?das conforme
morfologia, profundidade e tipo de sedimento. Quatro tipos de ecocar?teres s?smicos foram
identificados e mapeados, assim como suas respectivas formas de fundo, indicando distintos
processos sedimentares ao longo do vale inciso. A integra??o dos dados batim?tricos, de s?smica
rasa e sedimentologia sugerem uma ativa??o do vale inciso Apodi-Mossor? no Pleistoceno Tardio,
corroborando com a evolu??o morfol?gica-sedimentar deste setor da plataforma continental no
Quatern?rio. / Systems of incised valleys have been studied in different continental shelves, including the
Brazilian continental margin. The interest to characterize this feature is given by the information that it
can provide variations on sea level, as well as the ability to host economically significant quantities of
hydrocarbons in reservoirs located in deposits filling of the incised valleys. This thesis has the overall
objective to characterize the morphology and sedimentary cover of the incised valley Apodi-Mossor?,
located in the Northern Continental shelf of Rio Grande do Norte state, adjacent to Areia Branca city.
The methodology included the integration of satellite imagery, bathymetric data, sedimentological
data, shallow seismic, and the identification of foraminifera. The results indicate that the ApodiMossr?
incised valley is currently formed by two channels, shallow channel and deep channel, which
have distinct morphological and sedimentological characteristics. The deep channel has connection
with one of the heads of the Apodi Canyon, located in the slope area. The acquisition, processing
and interpretation of shallow seismic data allowed the recognition of the depositional surface,
erosional surface, discordance, and sismofaceis. The erosional surface mapped from shallow seismic
sections is possibly a indicative of an ancient surface of valley incision, where it would probably be
associated with the limit Pleistocene/Holocene. Different sismofaceis were identified and reflect the
rise in sea level with standards sometimes agradacional, sometimes progradational. The thickness of
sediments on this surface was estimated at a maximum of 22m thick in the central portion of the
incised valley. Statistically, there are differences between the adjacent continental shelf and
channels, and between these channels, for the content of calcium carbonate, organic matter, sand
and mud perceptual, except for the gravel grain size. The analysis of living and dead foraminifera
showed the presence of fifty species distributed in regards to morphology, depth and type of
sediment. Four type of seismic echocharacteres were identified and mapped, as well as their
bedforms, indicating different sedimentary processes along the incised valley. The integration of
results suggests an activation of the Apodi-Mossor? incised valley in the Late Pleistocene.
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Caracteriza??o geomorfol?gica e sedimentar de uma plataforma tropical: ?rea Pirangi (Nordeste do Brasil)Pierri, Guilherme Cherem Schwarz 09 October 2015 (has links)
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Previous issue date: 2015-10-09 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / O avan?o das t?cnicas de investiga??o submarina vem motivando uma s?rie de pesquisas para o reconhecimento detalhado das caracter?sticas de Plataformas Continentais em todo o mundo. A Plataforma Continental tropical brasileira, especificamente, carece de informa??es neste n?vel, apesar de sua relev?ncia, tanto para explora??o de recursos naturais, quanto para conserva??o marinha. Esta tese, desenvolvida na ?rea Leste da Plataforma do Rio Grande do Norte, utiliza dados in?ditos adquiridos a partir de m?todos hidroac?sticos (sondas mono, multifeixe e de varredura lateral) e amostras sedimentares, apresentando uma an?lise detalhada da paisagem submarina e das caracter?sticas da cobertura sedimentar. Integram ?s informa??es abi?ticas, padr?es de distribui??o bi?tica, que possibilitaram a caracteriza??o de habitat para fundos consolidados na ?rea de Pirangi. Este setor da plataforma, considerado raso e estreito, possui uma divis?o n?tida entre os sedimentos superficiais, que recobrem as zonas interna (terr?genos) e externa (biog?nicos). Evidenciando as varia??es de n?vel do mar, antigas posi??es de linha de costa est?o preservadas em quatro alinhamentos recifais, al?m de um paleo-canal formado em per?odo de mar baixo, conservado ainda hoje pelo pequeno aporte sedimentar. A plataforma faminta por sedimentos apresenta ainda fei??es onduladas, pequenas dunas submersas compostas por cascalhos biocl?sticos. A avalia??o conjunta de par?metros abi?ticos e do padr?o de distribui??o da cobertura b?ntica, baseada em grupos foco, permitiu a individualiza??o de habitat para as superf?cies recifais, demonstrando uma sucess?o de habitat desde os recifes praiais at? os recifes fundos. Esta an?lise pode ser replicada para outras ?reas de Plataforma Continental e contribuir para o delineamento de planos de gest?o, para o necess?rio manejo sustent?vel de recursos naturais, bem como para a delimita??o de propostas de conserva??o marinha. / The advance on marine underwater research techniques has motivated many efforts aiming to detail and recognize the Continental Shelf features worldwide. The Brazilian tropical Continental Shelf specifically lacks information at this level, despite its importance, both for natural resources exploitation, as for marine conservation. This thesis, developed in the eastern Rio Grande do Norte Continental Shelf (Northeastern Brazil), uses new data acquired from hydroacoustic methods (singlebeam, multibeam and side scan sonars) and sedimentary samples, presenting a detailed analysis of the underwater landscape and sedimentary coverage. Combine biotic distribution patterns with abiotic information, enabling habitat classification for hard sea-bottoms at Pirangi area. This narrow and shallow shelf sector has a sharp division between the surface sediments that covers the inner (terrigenous) and external (biogenic) zones. Pointing out the sea level variations, ancient shorelines are preserved in four reef alignments (beachrocks), plus a palaeochannel formed during low sea-level periods, still conserved by the small sand supply. The sediment-starved shelf also presents wavy features, small submerged dunes composed by bioclastic gravel. The assembled evaluation of abiotic parameters and distribution pattern of benthic coverage, based on specific groups, allowed the individualization of habitats for reef surfaces, showing a habitat succession from coastal to offshore reefs. This analysis can be replicated to other Continental Shelf areas and contribute for management plans, for the necessary natural resources sustainable management, as well to the delimitation of marine conservation proposals.
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