388 resultados para tabuleiros costeiros


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Estuaries are coastal environments ephemeral life in geological time, derived from the drowning of the shoreline as a function of elevation relative sea level. Such parallel systems is characterized by having two sources of sediment, the river and the sea. The study area comprises the Acu River estuary, located on the northern coast of Rio Grande do Norte State, in a region of intense economic activity, mainly focused on the exploration of oil onshore and offshore, likely to accidental spills. In the oil sector are developed for salt production, shrimp farming, agriculture, fisheries and tourism, which by interacting with sensitive ecosystems, such as estuaries, may alter the natural conditions, thus making it an area susceptible to contamination is essential in understanding the morphodynamic variables that occur in this environment to obtain an environmental license. Information about the submarine relief the estuaries are of great importance for the planning of the activity of environmental monitoring, development and coastal systems, among others, allowing an easy management of risk areas, and assist in the creation of thematic maps of the main aspects of landscape. Morphodynamic studies were performed in this estuary in different seasonal periods in 2009 to observe and quantify morphological changes that have occurred and relate these to the hydrodynamic forcing from the river and its interaction with the tides. Thus, efforts in this area is possible to know the bottom morphology through records of good quality equipment acquired by high resolution geophysical (side-scan sonar and profiler current by doppler effect). The combination of these data enabled the identification of different forms of bed for the winter and summer that were framed in a lower flow regime and later may have been destroyed or modified forms of generating fund scheme than the number according Froude, with different characteristics due mainly to the variation of the depth and type of sedimentary material they are made, and other hydrodynamic parameters. Thus, these features background regions are printed in the channel, sandy banks and muddy plains that border the entire area

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This work focuses the geomorphological characterization and spatial data modeling in the shallow continental shelf within the Folha Touros limits (SB-25-CV-II), based on bathymetric data analysis and remote sensing products interpretation. The Rio Grande do Norte state is located in northeastern Brazil and the work area is located at the transition region between the eastern and northern portions of their coast. The bathymetric surveys were conduced between march and may 2009, using a 10 meters long vessel and 0.70 meters draught, equipped with global positioning system and echo sounder (dual beam, 200KHz , 14°). The fieldwork resulted in 44 bathymetric profiles espaced 1.5 km and 30 km average length. The bathymetric data amount were 111,200 points and were navigated 1395.7 km within na area about 1,850 km2. The bathymetric data were corrected for the tide level, vessel draught and were subsequently entered into a geographic information system for further processing. Analysis of remote sensing products was carried out using Landsat 7/ETM + band 1, from november 1999. The image was used for visualization and mapping submerged features. The results showed the presence of geomorphological features within the study area. Were observed, from the analysis of local bathymetry and satellite image, seven types of geomorphological features. The channels, with two longitudinals channels (e. g. San Roque and Cioba channels) and other perpendicular to the coast (e. g. Touros, Pititinga and Barretas). Coastal reef formations (Maracajaú, Rio do Fogo and Cioba). Longitudinal waves, described in the literature as longitudinal dunes. The occurrence of a transverse dune field. Another feature observed was the oceanic reefs, an rock alignment parallel to the coast. Were identified four riscas , from north to south: risca do Liso, Gameleira, Zumbi, Pititinga (the latter being described for the first time). Finally, an oceanic terrace was observed in the deepest area of study. Image interpretation corroborated with the in situ results, enabling visualization and description for all features in the region. The results were analysed in an integrating method (using the diferent methodologies applied in this work) and it was essential to describe all features in the area. This method allowed us to evaluate which methods generated better results to describe certain features. From these results was possible to prove the existence of submerged features in the eastern shallow continental shelf of Rio Grande do Norte. In this way, the conclusions was (1) this study contributed to the provision of new information about the area in question, particularly with regard to data collection in situ depths, (2) the method of data collection and interpretation proves to be effective because, through this, it was possible to visualize and interpret the features present in the study area and (3) the interpretation and discussion of results in an integrated method, using different methodologies, can provide better results

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The aim of this study was the seasonal characterization of the morphology, sedimentology and hydrodynamic of the Açu, Cavalos and Conchas estuaries. These estuaries are inserted in a semi-arid climate area and form the mouth of the hydrographic basin of the Piranhas-Açu river, that represent the discharge of the largest watershed in the state. They are embedded in an environment consisting of a fluvial-marine floodplain, mangrove ecosystem, sandbanks, fields of dunes, spits and sandy beaches. Adjacent to the natural units are the main local socioeconomic activities (oil industry, salt industry, shrimp farming, fishing and tourism) are dependent on this river and its conservation. The environmental monitoring is necessary because it is an area under constant action of coastal processes and at high risk of oil spill. The acquisition and interpretation of hydrodynamic, sonographic and sediment data was conducted in two campaigns, dry season (2010) and rainy season (2011), using respectively the current profiler ADCP Doppler effect, the side-scan sonar and Van Veen sampler. In these estuaries: Açu, Cavalos and Conchas were identified the following types of bedforms: flatbed and Dunes 2-D and 3-D (small to medium size), generated at lower flow regime (Froude number <1). Structures such as ripples were observed in the Açu estuary mouth. The higher values of flow discharge and velocity were recorded in the Açu estuary (434,992 m³.s-¹ and 0,554 m.s-¹). In rainy season, despite the record of highest values of discharge and flow velocities at the mouth, the energy rates upstream did not differ much from the data of the dry season. However, in all estuaries were recorded an increase in speed and flow, with reservation to the flow in the Açu estuary and flow at the mouth of the Conchas estuary. Sediment grain sizes tend to increase towards the mouth of the estuary and these ranged from very fine sand to very coarse sand, medium sand fraction being the most recurrent. Based on the data acquired and analyzed, the estuaries Açu, Cavalos and Conchas are classified as mixed , dominated by waves and tides. According to their morphology, they are classified as estuaries constructed by bar and according to the classification by salinity, estuaries Conchas and Cavalos were ranked as hypersaline estuaries, and Açu as hypersaline and vertically well mixed type C

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The Camorim Oilfield, discovered in 1970 in the shallow water domain of the Sergipe Sub-basin, produces hydrocarbons from the Carmópolis Member of the Muribeca Formation, the main reservoir interval, interpreted as siliciclastics deposited in an alluvial-fluvial-deltaic context during a late rifting phase of Neoaptian age, in the Sergipe-Alagoas Basin. The structural setting of the field defines different production blocks, being associated to the evolution of the Atalaia High during the rift stage and subsequent reactivations, encompassing NE-SW trending major normal faults and NWEW trending secondary faults. The complexity of this field is related to the strong facies variation due to the interaction between continental and coastal depositional environments, coupled with strata juxtaposition along fault blocks. This study aims to geologically characterize its reservoirs, to provide new insights to well drilling locations in order to increase the recovery factor of the field. Facies analysis based on drill cores and geophysical logs and the 3D interpretation of a seismic volume, provide a high resolution stratigraphic analysis approach to be applied in this geodynamic transitional context between the rift and drift evolutionary stages of the basin. The objective was to define spatial and time relations between production zones and the preferential directions of fluid flow, using isochore maps that represent the external geometry of the deposits and facies distribution maps to characterize the internal heterogeneities of these intervals, identified in a 4th order stratigraphic zoning. This work methodology, integrated in a 3D geological modelling process, will help to optimize well drilling and hydrocarbons production. This methodology may be applied in other reservoirs in tectonic and depositional contexts similar to the one observed at Camorim, for example, the oil fields in the Aracaju High, Sergipe Sub-basin, which together represent the largest volume of oil in place in onshore Brazilian basins

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This study was developed in the northern coast of the city of Macau, a total area of 88,52 km², located in the State of Rio Grande do Norte. It presents relatively plain surface, with interlaced of streams and gamboas, characterized by contributions of oceanic water, flooding areas of swamps. Altogether, the climatic and topographical conditions provide an ideal environment for the development of saline activity. Inserted in the geologic context of the Potiguar Basin, the region presents favorable conditions for the production of hydro-carbons. It still presents natural conditions for shrimp breeding and artisanal fishing. This work analyzes the transformations occurred in the land use, using air photographs of 1978, Landsat 5 ETM Images of 1988, 1998 and 2008. A secular analyzes was carried through the dynamics of the use of the territory and the transformations occurred in the landscape due to the increment of the productive activities. In the survey of the data for study of the area, it was verified that little alteration occurred in the 30 years. The saline activity that was present since the year of 1978 having an increase of about 5% in thirty years; the shrimp breeding activity that had its presence in the decade of 1990, presented a high growth in the land use, therefore in 1998 it presented 0.45% and currently it presents 6.59%. In the field it was observed that great areas used previously for the saline activity, today it is prepared for shrimp breeding and that the areas of petroleum exploration occupy salt mines, beaches and trays. In 1988 it presented a percentage of 0, 07% and currently it occupies 0.46%, having grown 50% in the last 10 years. Although the variation of the occupation of the area has been little expressive, shrimp breeding showed a growth of 1,200% in only 10 years. In regards to petroleum activity, there wasn t any demonstration of an increasing impact in the land use in the area of study in 26 years of exploration

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Considering that tourism tends to reproduce itself privatizing the areas where it installs, the secondary residence has been an urban element responsible for the private appropriation of the public spaces of coastal of Nísia Floresta. The private appropriation of these accesses, for secondary residences, constitute in an issue-problem of the research. The principal goal is to analyze the relationship of the consumers/users of secondary residences with the public space; and, specifically, identify how the government has been acting and manifesting itself about the occupation of the coastal of Nísia Floresta; as also to verify how the secondary residence has been appropriating privately of the public access of the coastal. On account of the scarce literature about secondary residences and the importance of the public access to beaches for the inhabitant, the present work aims to contribute to the discussion of this theme. The secondary residences in Rio Grande do Norte began in the late nineteenth century, becoming more common in the 90s, when the coast south of Natal is appropriated from local vacationers. In 2000, foreign investment began to be applied in real state and tourism, producing closed developments, served in leisure infrastructure, trade, and hospitality, mainly to external demands. The methodology included a bibliographic survey, data collection and in lócus observation. Applied questionnaires and interviews were performed with consumers/users of the secondary residences, permanent residents and government, respectively. To the legal grounding, taken as a reference the article. 10, of the law 7.661/88 to establish that the beaches are goods of common use . Considering the conclusive analysis of the research, can be said that the right of free access and use of the beach is committed for the benefit of the consumers/users of secondary residences, due to the negligence and omission of the government

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Issues concerning coastal regions, especially the beaches have sparked quite complex because studies are there that most people in the world has secured housing, mainly from the half of the last century, without concern for the natural dynamics of these environments, which have complex interactions of continental and oceanic, coastal responsible for changes in locations that can be perceived in a few years and sometimes even a few days or hours. The search took as main goal, analyze the Genipabu Beach, in the municipality of Extremoz/RN, fragile environment and rapid momentum, which has been occupied in a disorderly and unplanned. Carried out a beach monitoring through profiles beach environments: defined stages morphodynamics; realization of characterize hydrodynamic processes; identification of changes in the landscape. To this end, made necessary a survey from the bibliographic collection for theoretical and conceptual rationale. An empirical step for conducting the environmental characterization of hydrodynamics, leveling and topographic analysis of sediments (in laboratory), for observation of changes in features, influenced, and natural dynamics, anthropic action that increasingly comes taking the characteristics from the natural landscape. Underlines therefore the importance of academic studies in several areas in these environments, for setting up a coastal zoning giving public subsidies for managers for managing and planning the use and occupation of the coast in their areas

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

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Hydrographic basins always exercised a big fascination over humankind that attracted for its scenery beauty or for its richness in natural resources, had been acting in order to modify these important ecosystems without, therefore, considering the possible consequences of these changes. The attributed importance to the coast ecosystems, in eminence to the hydrographic basin of Punaú river and adjacent areas, is had when it s verified the diversity of the ecosystems that contemplate it. Hydrographic basin in evidence in Rio Grande do Norte state, occupies an area of nearly 652.71 km², being it sited in the homogeneous micro-region Litoral Nordeste, with a regional population estimated in nearly 75,188 inhabitants, according to the Anuário Estatístico do Rio Grande do Norte 2004. The region of the researched basin is formed by seven municipal districts related as it follows: Maxaranguape, Pedra Grande, Pureza, Rio do Fogo, São Miguel de Touros, Taipu and Touros, but Maxaranguape, Rio do Fogo, Touros and Pureza have a direct participation in the basin. Basin in study have it lands evaluated according to the agriculturist aptitude by the conventionally methodology practiced in the country, having as objective, then, a compara-tive analysis between the ambient unities, Aeolian littoral and coast tray, identified in the researched area. From the characterization of the physic way of the area in study and owning the kept data, it was proceeded the integrated analysis of the structural elements of the landscape which were evidenced that the fragile areas are associated with the areas of agriculture cultivation, such as the ones of irregular occupation. About the degradation, the ambient diagnostic of the basin indicated that the equivalent to the Aeolian Littoral Ambient Unit correspond to the bigger pledging of the ambient quality, in other words, high ambient fragility, being this result due to the use and occupation of the soil, propitiating this way, vulnerability in the vegetal cover of the area, despite it disposes of a low agriculture cultivation percentage. Already in the Coast Ambient Tray, is emphasized the medium ambient fragility, despite of the high index of cultivated area. In a general way, the total area of the hydrographic basin of Punaú river and adjacent areas presented ambient impacts over the tolerance limit, indicating the necessity of a review of the practices of use and handling of the soil, reforesting of the water courses edges, control of erosion and contamination of the aqueous in the perspective to reduce the effects of the impacts due to the use and occupation of the basin in regard. The present search evaluated the ambient impacts diagnosised in the hydrographic basin of Punaú river and adjacent areas, pointing the causes and the probable consequences of the damages caused by these impacts to the basin ambient. From the analysis of these data, if was possible to become explicit how they are fundamental as key elements in the process of decision taking in the ambient questions

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This paper aims to present the results of systematic survey on clastic dykes in the Corumbataí Formation (Permian), in the northeast region of the State of São Paulo. Besides this, the paper analyses genetic aspects of those features as well as their stratigraphic and sedimentologic implications in terms of geologic evolution of the northeastern Paraná Sedimentary Basin during Permian times. The field works had been developed in 3 main Corumbataí Formation outcrops (2 road cuts and a quarry) supposed to show the most important clastic dikes occurrences in the studied area. Basically, the sedimentary intrusions are formed by fine sand or silt size particles and had penetrated host rocks as near-vertical, centimeter thick, dykes (most common form) or as horizontal sheets, forming clastic sills (subsidiary form), both with variable geometric forms and dimensions. A lot of dyke walls show undulations suggesting pre-diagenetic clastic intrusions, probably near the ancient depositional surface. Almost all intrusions occur in the superior third portion of the Corumbataí Formation and some similar features seem to appear in the adjoining superposed Pirambóia Formation base. In this article the authors defend a seismic origin hypothesis for the clastic intrusions. It is important to mention that clastic intrusions tend to occur linked to expressive seismic events, with magnitude upper to 5. The analysis of isopach maps of the Permian and Mesozoic units of the Paraná Sedimentary Basin in the study area suggests a depositional system changing, from epicontinental sea conditions to shallow platform and, finally, to coastal deserts. Probably, this environmental change was driven by regional uplift accompanied by seismic events. It is possible that ancient seismicity triggered liquefaction processes and the resulting clastic intrusions. In this sense, those clastic features might be properly namedseismites.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)