Mapeamento da zona costeria protegida por arenitos de praia (Beachrocks) em Nísia Floresta - RN

The goal of this work comprises the detailed mapping of the coastal zone of the south coast of the State of Rio Grande do Norte. The emphasis of the study is the units of beachrocks and the features of the physical environment associated. The mapping of the beachrocks and of the adjacent coastal features is justified, among other aspects, by the fact that the beachrocks constitute an important protection agent against the sea erosion. By one side, they dissipate the energy of the sea waves and make possible the imprisonment of sediments in the foreshore. The beachrocks in the studied area are constituted of discontinuous strips, parallel to the coast line presenting emerged in some places, even in the highest tides, entirely submerged or partially buried by coastal sediments. These sandstones compose the landscape of big part of the coast and they are responsible for the partial dissipation of the energy of the waves on the studied coast. The methodology used in this work consisted of different techniques were used, as the use of aerial pictures of small format (FAPEFs), acquisition of data of system of global positioning (GPS) and later elaboration of thematic maps and of digital models of soil (MDTs). The results obtained in the mapping of the use and occupation of the soil, demonstrate the existence of strong human pressure in the coastal area (built lots and no built), occupying about 54,74% of built areas. This problem has been taking to degradation risks due to the inconsequent expansion of divisions into lots and tourist enterprises. The MDT came as an excellent resource, as visual as functional, being possible to visualize several angles and to act in three dimensions the relief of the area in study, as well as to identify the present features in the coastal area. By the importance of the bodies of beachrocks as a protection agent against the coastal erosion, faces were delimited in the sandstones based in geometric criteria, classifying them in, central face, outside face, inside face, break and undermiming. These last two associates to the erosion and washout in the base of these bodies. Field data indicate clearly that the most important process in the fracturing of the bodies is associated with mechanisms related to the gravity, being the joints formed by processes of gravitational sliding. Finally, the mapping of the coastal zone starting from aerial pictures of small format it made possible the identification of the elements that compose the beach strip, for accomplishing with larger detailed level and by presenting a better monitoring of the dynamics of the coastal zone

Beachrocks do Rio Grande Do norte: correlação entre os depósitos costeiros e os de zona costa-afora com base na faciologia, petrografia e diagênese

Beachrocks são rochas sedimentares formadas pela cimentação de sedimentos praiais por carbonato de cálcio em especial, calcita e/ou aragonita em zona de estirâncio. A ocorrência dessas rochas é bastante comum em diversas partes do globo, sobretudo em regiões com latitudes inferiores a 40º. O Rio Grande do Norte possui grande quantidade de beachrocks, os quais afloram tanto em regiões costeiras quanto em zona costa-afora. Os depósitos de beachrocks de zona costeira do referido estado têm sido estudados por diversos autores, os quais abordaram os mais variados temas desde o início do século XX. Por outro lado, os depósitos de zona costa-afora apesar de terem sido estudados por poucos autores têm ganhado atenção apenas nos últimos anos. Porém, nenhum trabalho até o presente fez algum tipo de estudo comparativo de cunho geológico entre os corpos de beachrocks presentes em ambas as zonas: costeira e costa-afora. Sendo assim, a presente dissertação teve o intuito de correlacionar os corpos de beachrocks que afloram em zona costeira aos que estão atualmente dispostos em zona costa-afora, próximo a isóbata de 25 m, levando em consideração seus aspectos petrográficos, diagenéticos e sedimentológicos. Para isso, foram percorridos cerca de 260 km de litoral, correspondendo ao trecho entre os municípios de Extremoz e Tibau, em busca de afloramentos de beachrocks. Seções colunares foram confeccionadas e amostras coletadas em estações de amostragem representativas da zona costeira, ao passo que da zona costa-afora apenas seções delgadas foram analisadas. Trabalhos disponíveis na literatura sobre o tema e área em pauta também foram utilizados. A partir dos dados levantados, observou-se que os beachrocks são formados por diferentes camadas ao longo de um perfil vertical. Estas camadas são claramente identificadas em afloramento pela diferença existente na composição, textura e estruturas sedimentares peculiares a cada uma delas. Seções delgadas foram confeccionadas e analisadas a partir de amostras coletadas nas diferentes camadas de diversos afloramentos. Um afloramento foi escolhido como afloramento modelo sendo este o de São Bento do Norte por apresentar a maior espessura de rocha aflorante (1,9 m). Este tem sido muito bem estudado tanto no corrente trabalho quanto em trabalhos de outros autores. A este foram comparados todos os outros afloramentos analisados. A partir da análise micropetrográfica, foram identificadas 03 microfácies para os beachrocks do Rio Grande do Norte, sendo elas: Quartzarenítica (< 2,9% de bioclastos), Quartzarenítica Bioclástica (entre 3 e 9,9% de bioclastos) e Bio-quartzarenítica (> 10% de bioclastos). Associando essas microfácies às análises sedimentológicas realizadas foi possível propor que as microfácies Quartzarenítica e Bio-quartzarenítica foram depositadas em zona de estirâncio enquanto que a microfácies Quartzarenítica Bioclástica foi depositada em zona de face litorânea superior. A história diagenética dos beachrocks estudados é marcada por quatro principais processos: compactação mecânica, cimentação, dissolução e geração de porosidade secundária, e oxidação. Dentre esses, o processo de cimentação é o mais importante, sendo caracterizado por precipitação de cimento de calcita rica em Mg sob cinco morfologias, a saber: cutículas criptocristalinas, franjas prismáticas isópacas, calcita espática microcristalina, calcita espática equante e agregados pseudo-peloidais. Todas estas morfologias foram formadas durante o estágio de eodiagênese, nas zonas freática marinha ativa ou freática meteórica ativa, corroborando assim com a idéia de que beachrocks têm sua litificação completa a pequenas profundidades. Associando as análises microfaciológicas às diagenéticas foi possível sugerir que a sucessão vertical de camadas vista em alguns beachrocks costeiros representam registros de variações de mais alta frequência do nível do mar durante o Holoceno. A partir daí, baseando-se em informações obtidas através de curvas de variação do nível do mar relativo no Holoceno para o Rio Grande do Norte, disponíveis na literatura, e na correlação aqui realizada entre os beachrocks costeiro e aqueles de zona costa-afora, foi possível inferir que estes últimos representam uma antiga linha de costa formada a idades relativas superiores a 7.000 anos A.P

Caracterização batimétrica e fisicooceanográfica do canal de acesso ao porto de Cabedelo/PB: uma análise ambiental ao derrame de óleo

The State of Paraíba is one of the most dynamic states of Brazil, strategically located in the northeast, is notable for the excellent potential for integration of different transportation modes forming the states of Rio Grande do Norte, Pernambuco and Alagoas. The dynamic that occurs with port activity causes changes in the space where it is installed. And the elements of this space are always more than suffering direct or indirect influences as the flow in the port is expanded. Therefore, this region became subject to the accidental spillage of oil, because it presents a heavy traffic of ships of various sizes that can run aground or collide with oil causing accidental events. The study of geomorphological and sedimentological compositions of seafloor becomes important as more is known about the relationships between these parameters and associated fauna, and can identify their preferred habitats. The database background, acoustically collected along the proposed study area, is a wealth of information, which were duly examined, cataloged and made available. Such information can serve as an important tool, providing a geomorphological survey of the sedimentary area studied, and come to subsidize, in a flexible, future decision making. With the study area Port of Cabedelo, Paraíba - Brazil, this research aimed to evaluate the influence of the tidal surface and background in modeling the seabed, including the acquisition of information about the location of submerged rocky bodies and the depth of these bodies may turn out to be natural traps for the trapping of oil in case of leaks, and obtain the relationship between types of bed and the hydrodynamic conditions present in the region. In this context, for this study were collected bathymetric data (depth) and physical oceanographic (height of water column, water temperature, intensity and direction of currents, waves and turbidity), meteorological (rainfall, air temperature, humidity, winds and barometric pressure) of the access channel to the Port of Cabedelo / PB and its basin evolution (where the cruise ships dock), and includes tools of remote sensing (Landsat 7 ETM +, 2001), so that images and the results are integrated into Geographic Information Systems and used in the elaboration of measures aimed at environmental protection areas under the influence of this scale facilities, serving as a grant to prepare a contingency plan in case of oil spills in the region. The main findings highlight the techniques of using hydroacoustic data acquisition together bathymetric surveys of high and low frequency. From there, five were prepared in bathymetric pattern of Directorate of Hydrography and Navigation - DHN, with the depth in meters, on a scale of 1:2500 (Channel and Basin Evolution of Access to Port of Cabedelo), where there is a large extent possible beachrocks that hinder the movement of vessels in the port area, which can cause collisions, running aground and leaking oil. From the scatter diagram of the vectors of currents, it can be seen as the tidal stream and undergoes a channeling effect caused by the bidirectional effect of the tide (ebb and flood) in the basin of the Port of Cabedelo evolution in NW-direction SE and the highest speed of the currents occurs at low tide. The characterization weather for the period from 28/02 to 04/07/2010 values was within the expected average for the region of study. The multidisciplinary integration of products (digital maps and remote sensing images), proved to be efficient for the characterization of underwater geomorphological study area, reaching the aim to discriminate and enhance submerged structures, previously not visible in the images

Modelagem do clima de ondas e seus efeitos sobre as feições morfológicas costeiras no litoral setentrional do Rio Grande do Norte

This thesis presents the results of application of SWAN Simulating WAves Nearshore numerical model, OF third generation, which simulates the propagation and dissipation of energy from sea waves, on the north continental shelf at Rio Grande do Norte, to determine the wave climate, calibrate and validate the model, and assess their potential and limitations for the region of interest. After validation of the wave climate, the results were integrated with information from the submarine relief, and plant morphology of beaches and barrier islands systems. On the second phase, the objective was to analyze the evolution of the wave and its interaction with the shallow seabed, from three transverse profiles orientation from N to S, distributed according to the parallel longitudinal, X = 774000-W, 783000-W e 800000-W. Subsequently, it was were extracted the values of directional waves and winds through all the months between november 2010 to november 2012, to analyze the impact of these forces on the movement area, and then understand the behavior of the morphological variations according to temporal year variability. Based on the results of modeling and its integration with correlated data, and planimetric variations of Soledade and Minhoto beach systems and Ponta do Tubarão and Barra do Fernandes barrier islands systems, it was obtained the following conclusions: SWAN could reproduce and determine the wave climate on the north continental shelf at RN, the results show a similar trend for the measurements of temporal variations of significant height (HS, m) and the mean wave period (Tmed, s); however, the results of parametric statistics were low for the estimates of the maximum values in most of the analyzed periods compared data of PT 1 and PT 2 (measurement points), with alternation of significant wave heights, at times overrated with occasional overlap of swell episodes. By analyzing the spatial distribution of the wave climate and its interaction with the underwater compartmentalization, it was concluded that there is interaction of wave propagation with the seafloor, showing change in significant heights whenever it interacts with the seafloor features (beachrocks, symmetric and asymmetric longitudinal dunes, paleochannel, among others) in the regions of outer, middle and inner shelf. And finally, it is concluded that the study of the stability areas allows identifications of the most unstable regions, confirming that the greatest range of variation indicates greater instability and consequent sensitivity to hydrodynamic processes operating in the coastal region, with positive or negative variation, especially at Ponta do Tubarão and Barra do Fernandes barrier islands systems, where they are more susceptible to waves impacts, as evidenced in retreat of the shoreline

Estudo geológico e geofísico da falha de carnaubais, Bacia Potiguar-RN, e implicações neotectônicas

The segment of Carnaubais Fault located in the southeasthern portion of Guamaré Graben (Potiguar Basin) was studied. Several structures were detected and some of them strongly suggest that the last movements in Carnaubais Fault are of Neotectonic age. The study comprises an integrated interpretation of geologic, geomorphologic and geophysical data (gravimetry, magnetometry, resistivity, and self potential methods). According to the size of the studied areas, two approaches were used in this research. The first approach is of a regional nature and was conducted in an area, hereafter named Regional Area, having approximately 6,000 km2 and localized in the northern portion of Rio Grande do Norte state, around Macau city. The second approach comprises detailled studies of two small areas inside the Regional Area: the Camurupim and São Bento areas. Gravimetric and topographic data were used in the Regional Area. A separation into regional and residual components were conducted both on gravimetric and topographic data. The interpretation of the residual component of the gravimetric data allows a precise mapping of the borders of the Guamaré Graben. The regional component features of the topographic data are controlled by the pair of conjugate faults composed by the Carnaubais Fault (NE direction) and the Afonso Bezerra Fault (NW direction). On the other hand, the residual component of the topographic data shows that river valleis of NW direction are sharply interrupted where they intersect Carnaubais Fault. This fact is interpreted as an evidency that the last significant moviments occured in the Carnaubais Fault. Geologic, geomorphologic and geophysical data (magnetometry, resistivity, and self potential methods) were used in the Camurupim Area. The geologic mapping allows to identify five lithophacies unities. The first two unities (from base to top) were interpreted as composing a marine (or transitional) depositional sequency while the other were interpreted is composing a continental depositional sequence. The two sequences are clearly separated of an erosional discordance. The unities grouped in the marine sequence are composed by calcarenites (Unity A) and mudstones (Unity B). Unity A was deposited in a shalow plataform while Unity B, in a tidal flat. The unities grouped in the continental sequence are composed of conglomerate (Unity C) and sandstones (Unities D and E). Unities C and D are fluvial deposits while unity E is an eolian deposit. Unities A and B can be stratigraphycally correlated with Guamaré Formation. Unities C and D present three possible correlations. They may be correlated with Tibau Formation; or with Barreiras Formation; or with a clastic sediment deposit, commonly found in some rivers of Rio Grande do Norte state, and statigraphycally positioned above Barreiras Formation. Based on the decrease of the grain sizes from base to top both on unities C and D, it is proposed that these unities are correlated with the clastic sediment above mentioned. In this case, these unities would have, at least, Pleistocenic age. Finally, it is proposed that Unity E represent an eolian deposit that sufferred recent changes (at least in the Quaternary). The integrated interpretation of hydrographic, morphologic and geophysical data from Camurupim Area shows that Carnaubais Fault is locally composed by a system of several paralel subvertical faults. The fault presenting the larger vertical slip controls the valley of Camurupim river and separates the area in two blocks; in the nothern block the top of the Jandaira limestone is deeper than in the southern block. In addition, at least one of the faults in the northern block is cutting the whole sedimentary section. Because unities C , D, and/or E may be of Quaternary age, tectonic moviments possibly occured in Carnaubais Fault during this period. Detailled geologic mapping were conducted in beachrocks found in São Bento Area. This area is located at the intersection of the coast line with the Carnaubais Fault. The detected structures in the beachrocks are very similar to those caused by fragile deformations. The structures mapped in the beachrocks are consistent with a stress field with maximun compressional stress in E-W direction and extensional stress in the N-S direction. Since the Carnaubais Fault has a NE direction, it is optimally positioned to suffer tectonic movements under the action of such stress field. In addition, the shape of the coastal line appear to be controlled by the Carnaubais Fault. Furthemore, the observed structures in Camurupim Área are consistent with this stress field. These facts are interpreted as evidences that Carnaubais Fault and beachrocks suffered coupled tectonic movements. These moviments are of Neotectonic age because the beachrocks present ages less than 16,000 years

Caracterização morfológica e sedimentologica da plataforma, continental brasileira adjacente aos municípios de Fortim, Aracati e Icapuí- CE

The study area is located on the Brazilian Continental Shelf adjacent to Ceará State, inserted in the submerged Potiguar Basin. This area was submitted to extensional efforts during Upper Cretaceous, associated to the begining of the rifting that resulted in African and South American Continent separation. The main goal of this research was to better understand the sedimentary and geomorphological characteristics of the continental shelf adjacent to Fortim, Aracati and Icapuí (Ceará State). The used data base included geophysical (sides scan sonar and bathymetry studies) and sedimentological survey, associated to satellite image processing and interpretation. Inferences about suspended material and longshore drift was possible using satellite images, and differente bedforms were characterized such as: different kinds of dunes (longitudinal, cross and oblique), bioclastic banks, paleochannels, flat and rock bottom. The researched area comprehended about 2509,13 km2, where 6 different sedimentary facies, based on sediment composition and texture, could be recognized, such as: Bioclastic Sand, Siliciclastic Sand, Biosiliciclastic Sand, Bioclastic gravel, Biosiliciclastic sand with granule and gravel, and Silicibioclastic sand with granule and gravel. The integration of bathymetric, satellite image, side scan sonar and sedimentological data allow us a better characterization of this continental shelf area, as to advance in the knowledge of the continental shelf of the state of Ceara, a very important area to the oil industry because of its potential exploration and e exploitation, and to environmental survey as well

Geoprocessamento de dados meteo-oceonográficos (cor do oceano e temperatura da superfície do mar) aplicado ao monitoramento ambiental na costa setentrional do Rio Grande do Norte

Orbital remote sensing has been used as a beneficial tool in improving the knowledge on oceanographic and hydrodynamic aspects in northern portion of the continental shelf of Rio Grande do Norte, offshore Potiguar Basin. Aspects such as geography, temporal and spatial resolution combined with a consistent methodology and provide a substantial economic advantage compared to traditional methods of in situ data collecting. Images of the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor onboard NASA's AQUA satellite were obtained to support systematic data collections related to the campaign of environmental monitoring and characterization of Potiguar Basin, held in May 2004. Images of Total Suspension Matter (TSM) and values of radiance standard were generated for the calculation of concentrations of total suspension matter (TSM), chlorophyll-a and sea surface temperature (SST). These data sets were used for statistical comparisons between measures in situ and satellite estimates looking validate algorithms or develop a comprehensive regional approach empirically. AQUA-MODIS images allowed the simultaneous comparison of two-dimensional water quality (total suspension matter), phytoplankton biomass (chlorophyll-a) variability and physical (temperature). For images of total suspension matter, the generated models showed a good correlation with the field data, allowing quantitative and qualitative analysis. The images of chlorophyll-a showed a consistent correlation with the in situ values of concentration. The algorithms adjusted for these images obtained a correlation coefficient fairly well with the data field in order that the sensor can be having an effect throughout the water column and not just the surface. This has led to a fit between the data of chlorophyll-the integration of the average sampling interval of the entire water column up to the level of the first optical depth, with the data generated from the images. This method resulted in higher values of chlorophyll concentration to greater depths, due to the fact that we are integrating more values of chlorophyll in the water column. Thus we can represent the biomass available in the water column. Images SST and SST measures in situ showed a mean difference DT (SST insitu - SST sat) around -0.14 ° C, considered low, making the results very good. The integration of total suspension matter, chlorophyll-a, the temperature of the sea surface (SST) and auxiliary data enabled the recognition of some of the main ways to fund the continental shelf. The main features highlighted were submerged canyons of rivers Apodi and Açu, some of the lines and beachrocks reefs, structural highs and the continental shelf break which occurs at depths around -60 m. The results confirmed the high potential for use of the AQUA-MODIS images to environmental monitoring of sea areas due to ease of detection of the field two-dimensional material in suspension on the sea surface, temperature and the concentration of chlorophyll-a

Caracterização batimétrica e fisicooceanográfica do canal de acesso ao porto de Cabedelo/PB: uma análise ambiental ao derrame de óleo

The State of Paraíba is one of the most dynamic states of Brazil, strategically located in the northeast, is notable for the excellent potential for integration of different transportation modes forming the states of Rio Grande do Norte, Pernambuco and Alagoas. The dynamic that occurs with port activity causes changes in the space where it is installed. And the elements of this space are always more than suffering direct or indirect influences as the flow in the port is expanded. Therefore, this region became subject to the accidental spillage of oil, because it presents a heavy traffic of ships of various sizes that can run aground or collide with oil causing accidental events. The study of geomorphological and sedimentological compositions of seafloor becomes important as more is known about the relationships between these parameters and associated fauna, and can identify their preferred habitats. The database background, acoustically collected along the proposed study area, is a wealth of information, which were duly examined, cataloged and made available. Such information can serve as an important tool, providing a geomorphological survey of the sedimentary area studied, and come to subsidize, in a flexible, future decision making. With the study area Port of Cabedelo, Paraíba - Brazil, this research aimed to evaluate the influence of the tidal surface and background in modeling the seabed, including the acquisition of information about the location of submerged rocky bodies and the depth of these bodies may turn out to be natural traps for the trapping of oil in case of leaks, and obtain the relationship between types of bed and the hydrodynamic conditions present in the region. In this context, for this study were collected bathymetric data (depth) and physical oceanographic (height of water column, water temperature, intensity and direction of currents, waves and turbidity), meteorological (rainfall, air temperature, humidity, winds and barometric pressure) of the access channel to the Port of Cabedelo / PB and its basin evolution (where the cruise ships dock), and includes tools of remote sensing (Landsat 7 ETM +, 2001), so that images and the results are integrated into Geographic Information Systems and used in the elaboration of measures aimed at environmental protection areas under the influence of this scale facilities, serving as a grant to prepare a contingency plan in case of oil spills in the region. The main findings highlight the techniques of using hydroacoustic data acquisition together bathymetric surveys of high and low frequency. From there, five were prepared in bathymetric pattern of Directorate of Hydrography and Navigation - DHN, with the depth in meters, on a scale of 1:2500 (Channel and Basin Evolution of Access to Port of Cabedelo), where there is a large extent possible beachrocks that hinder the movement of vessels in the port area, which can cause collisions, running aground and leaking oil. From the scatter diagram of the vectors of currents, it can be seen as the tidal stream and undergoes a channeling effect caused by the bidirectional effect of the tide (ebb and flood) in the basin of the Port of Cabedelo evolution in NW-direction SE and the highest speed of the currents occurs at low tide. The characterization weather for the period from 28/02 to 04/07/2010 values was within the expected average for the region of study. The multidisciplinary integration of products (digital maps and remote sensing images), proved to be efficient for the characterization of underwater geomorphological study area, reaching the aim to discriminate and enhance submerged structures, previously not visible in the images