BDTD - Biblioteca Digital de Teses e Dissertações
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Doctoral Thesis Geomorfologia e arquitetura interna do vale inciso do Rio Açu na bacia potiguar imersa (NE Brasil)(Universidade Federal do Rio Grande do Norte, 2012) Gomes, Moab Praxedes; Vital, Helenice; Macedo, José Wilson de Paiva; http://lattes.cnpq.br/8074712340427454; Costa Neto, Leão Xavier; http://lattes.cnpq.br/1059276496317561; http://lattes.cnpq.br/3595069999049968; http://lattes.cnpq.br/2086362176219605; Xavier Neto, Pedro; http://lattes.cnpq.br/0420885770350995; Caldas, Luciano Henrique de Oliveirac; http://lattes.cnpq.br/1850164003052269The tectonic-sedimentary framework of a marginal basin contains traces of the marine and continental history of certain portion of planet Earth. The evolution of passive margins, specifically on continental shelves, has been intensively studied over the last century, because of the economic and scientific interests. Moreover, the recent methodological and technical advances in field data collection and analysis have transformed shallow marine studies from descriptive to quantitative and based on integration of different datasets. This Thesis presents the integration of multidisciplinary data (Landsat images, gravimetry, altimetry, singlebeam bathymetry, sonography, shallow seismic, sedimentology, current measurements and observations by SCUBA diving) which allowed the analysis of geomorphological expression of the northern Continental Shelf of the Rio Grande Norte state (NE-Brazil) and its correlation with their last phases of sedimentation in the context of the submerged Potiguar Basin, including sea-level fluctuations in the Quaternary, pre-Holocene subaerial exposure, the establishment of the Holocene currents on continental shelf, and pre-Cenozoic tectonic fault reactivation. This shelf is shallow, narrow and can be divided into inner, middle and outer shelf, and displays several geomorphological features. Its geometry and morphology is controlled by neotectonics. On it, there is an incised valley of the Rio Acu, a key element in the last stratigraphic record of Holocene transgression. The morphology of the Açu incised valley aligns with the central axis of Potiguar Basin and is strongly influenced by neotectonics in the context of the Domain Equatorial Atlantic Margin. The incised valley-fill was controlled by the morphology during transgression, as well as the morphology constraints the hydrodynamic processes and dispersal of siliciclastic and carbonate sediments during periods of highstand. Patch reefs, with coraline algae colonies were found between 20 and 40 m water depth. It allowed inferences about the mixed sedimentation in the Pleistocene and Holocene. These results contribute to the study of paleo-environmental conditions of the Quaternary, analogues reservoirs, shallow marine depositional models of high-energy tropical shelf, hydrocarbon exploration, geotechnical, environmental matters, navigation and others.Doctoral Thesis Geomorfologia e arquitetura interna do vale inciso do rio açu na bacia potiguar imersa (NE Brasil)(Universidade Federal do Rio Grande do Norte, 2012-11-23) Gomes, Moab Praxedes; Vital, Helenice; ; http://lattes.cnpq.br/3595069999049968; ; http://lattes.cnpq.br/2086362176219605; Macedo, José Wilson de Paiva; ; http://lattes.cnpq.br/8074712340427454; Neto, Leão Xavier Costa; http://lattes.cnpq.br/1059276496317561; Neto, Pedro Xavier; Caldas, Luciano Henrique de Oliveira; ; http://lattes.cnpq.br/1850164003052269The tectonic-sedimentary framework of a marginal basin contains traces of the marine and continental history of certain portion of planet Earth. The evolution of passive margins, specifically on continental shelves, has been intensively studied over the last century, because of the economic and scientific interests. Moreover, the recent methodological and technical advances in field data collection and analysis have transformed shallow marine studies from descriptive to quantitative and based on integration of different datasets. This Thesis presents the integration of multidisciplinary data (Landsat images, gravimetry, altimetry, singlebeam bathymetry, sonography, shallow seismic, sedimentology, current measurements and observations by SCUBA diving) which allowed the analysis of geomorphological expression of the northern Continental Shelf of the Rio Grande Norte state (NE-Brazil) and its correlation with their last phases of sedimentation in the context of the submerged Potiguar Basin, including sea-level fluctuations in the Quaternary, pre-Holocene subaerial exposure, the establishment of the Holocene currents on continental shelf, and pre-Cenozoic tectonic fault reactivation. This shelf is shallow, narrow and can be divided into inner, middle and outer shelf, and displays several geomorphological features. Its geometry and morphology is controlled by neotectonics. On it, there is an incised valley of the Rio Acu, a key element in the last stratigraphic record of Holocene transgression. The morphology of the Açu incised valley aligns with the central axis of Potiguar Basin and is strongly influenced by neotectonics in the context of the Domain Equatorial Atlantic Margin. The incised valley-fill was controlled by the morphology during transgression, as well as the morphology constraints the hydrodynamic processes and dispersal of siliciclastic and carbonate sediments during periods of highstand. Patch reefs, with coraline algae colonies were found between 20 and 40 m water depth. It allowed inferences about the mixed sedimentation in the Pleistocene and Holocene. These results contribute to the study of paleo-environmental conditions of the Quaternary, analogues reservoirs, shallow marine depositional models of high-energy tropical shelf, hydrocarbon exploration, geotechnical, environmental matters, navigation and others.Master Thesis Aquisição, processamento e análise de dados de sísmica de alta resolução na plataforma continental norte do Rio Grande do Norte: Vale inciso do Rio Açu(Universidade Federal do Rio Grande do Norte, 2008-08-26) Gomes, Moab Praxedes; Vital, Helenice; ; http://lattes.cnpq.br/3595069999049968; ; http://lattes.cnpq.br/2086362176219605; Macedo, José Wilson de Paiva; ; http://lattes.cnpq.br/8074712340427454; Xavier Neto, Pedro;On the modern Continental Shelf to the north of Rio Grande do Norte state (NE Brazil) is located a paleo-valley, submerged during the last glacial sea-level lowstand, that marks continuation of the most important river of this area (Açu River). Despite the high level of exploration activity of oil industry, there is few information about shallow stratigraphy. Aiming to fill this gap, situated on the Neogene, was worked a marine seismic investigation, the development of a processing flow for high resolution data seismic, and the recognition of the main feature morphology of the study area: the incised valley of the River Açu. The acquisition of shallow seismic data was undertaken in conjunction with the laboratory of Marine Geology/Geophysics and Environmental Monitoring - GGEMMA of Federal University of Rio Grande do Norte UFRN, in SISPLAT project, where the geomorphological structure of the Rio paleovale Açu was the target of the investigation survey. The acquisition of geophysical data has been over the longitudinal and transverse sections, which were subsequently submitted to the processing, hitherto little-used and / or few addressed in the literature, which provided a much higher quality result with the raw data. Once proposed for the flow data was developed and applied to the data of X-Star (acoustic sensor), using available resources of the program ReflexW 4.5 A surface fluvial architecture has been constructed from the bathymetric data and remote sensing image fused and draped over Digital Elevation Models to create three-dimensional (3D) perspective views that are used to analyze the 3D geometry geological features and provide the mapping morphologically defined. The results are expressed in the analysis of seismic sections that extend over the region of the continental shelf and upper slope from mouth of the Açu River to the shelf edge, providing the identification / quantification of geometrical features such as depth, thickness, horizons and units seismic stratigraphyc area, with emphasis has been placed on the palaeoenvironmental interpretation of discordance limit and fill sediment of the incised valley, control by structural elements, and marked by the influence of changes in the sea level. The interpretation of the evolution of this river is worth can bring information to enable more precise descriptions and interpretations, which describes the palaeoenvironmental controls influencing incised valley evolution and preservation to provide a better comprehensive understanding of this reservoir analog system