Evolução geomorfológica, (des)caracterização e formas de uso das Lagoas da cidade do Natal-RN

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Estudos sedimentológicos e o contexto estrutural da formação Serra do Martins, nos platôs de Portalegre, Martins e Santana/RN

This dissertation deals with sedimentological and structural framework of the siliciclastic rock of the Serra do Martins Formation (FSM) in the Portalegre, Martins and Santana plateau, located to the south of Potiguar Basin, in the southwest and central Rio Grande do Norte state. This formation, regarded as of Oligo-Miocene age based on intrusive relations of the Miocene Macau volcanics, has a still disputable age due to the lack of appropriate bio and/or chronostratigraphic markers. The FSSM deposits crop out along 650 to 750 m high plateau, as a remanescent sedimentary cover directly overlying topographically uplifted pre-cambrian crystalline rocks. During the last decades, these deposits were interpreted according to a Tertiary paleoclimatic evolutionary model, associated to pedogenetic processes. The sedimentological characterization of the FSM was done through a detailed study of its facies, petrography and diagenetic features. The facies study was based on description of field relations, textures and structures, the piling up of the strata and their lateral variations. The FSM was deposited by an anastomosing to coarse-meandering fluvial system, including deposits of lag, cannel-fill, ouver-bank and flood plain. The petrographic composition of the sediments, coupled to their facies and paleocurrent directions, suggest a rather distal sourcearea, to the south of the present plateau. The diagenetic study identified an incipient grain mechanical compaction, pronounced dissolution of the framework, matrix and/or cement components, intense precipitation of kaolinite, silic and, eventually, iron oxides, besides mechanical infiltration of the clays. Most of these events, regarded in the literature as associated to near-surface conditions (eo or telodiagenesis), indicate the FSM sediments were never deeply buried. Topographic relations along longitudinal and transversal sections reaching the Potiguar Basin to the north identified regional dips that allow to discuss stratigraphic correlations between the FSM and the basin formations. The sedimentological features of the different units and the intrusive relations of the Macau volcanics were also considered in these correlations,which support the Oligo-Miocene age previously accepted for the FSM. Concerning the tectonic framework of the FSM, this work investigated the pre-cambrian to cretaceous heritage and the cenozoic deformation, allowing the recognition of pre-, sin and post-FSM structures. The crystalline basement, belonging to the Seridó Belt, displays NE and WNW foliation trends related to the Brasiliano-age ductile shear zones. In this terrain, brittle-ductile and brittle NE- and NW-trending structures, associated with extensional joints filled with pegmatites and quartz veins, are related to an E-W compression by the end of Brasiliano Cycle. The E-W joints and NE-trending fractures were reactivated by N-S to N-S to NW extension during late Jurassic to Cretaceous times, controlling the emplacement of the Rio Ceará-Mirim basic dyke swarm and the opening of the Potiguar rift basin

Análise multitemporal dos elementos geoambientais da região da Ponta do Tubarão, área de influência dos campos petrolíferos de Macau e Serra, município de Macau/RN

The study area is inserted in Ponta do Tubarão region, Macau City, setentrional littoral of Rio Grande do Norte State, composed of Tertiary and Quatemary sedimentary rocks and sediments. This region is characterized for the intense action of the coastal processes, causing the morphologic instability in part of the area, beyond the interference of human activities, as the Petroliferous Industrial Polo, salt companies and shrimp farms. This justifies the integration of multidisciplinary and multitemporal detailed scientific studies dealing with the evaluation of the changing behavior of this coastal environment by geoenvironments elements characterization, identifying protected and recuperation areas, mainly those under socioeconomic intervention. The main objective was the coastal monitoring using geoprocessing techniques to prepare thematic maps useful for oil spilling environment risk areas survey. The methodology was based on multitemporal interpretation of remote sensing images and field checking, integrated in a Geographical Information System (GIS). The Geologic, Geomorphologic, Vegetation, Soil and Land Use maps were prepared, and later on they allowed the generation of the Natural Vulnerability and Environmental Vulnerability maps. These maps had been classified in accordance with vulnerability degrees: very low, low, medi um, high and very high. Beyond these maps the GIS allowed the analysis of the shoreline evolution for 10 distinct dates, using Landsat 5 TM and 7 ETM+ and SPOT-HRVIR images. This analysis made possible the attendance of the coastal morphodynamic evolution, where the results had been represented by areasof erosion and accretion (or deposition) of sediments, pointing critical areas under erosive process to the petroliferous industry (Macau and Serra fields). The GIS also provided to prepare the Environmental Sensitivity Maps of Oil Spill (SAO Maps) in operational scale (1: 10.000), according to the norms ofthe Ministério do Meio Ambiente (MMA 2002). The SAO Map in operational scale was based on IKONOS images mosaic where the ESI (Environmental Sensitivity Index) was represented according with two tides phases of theregion. Therewere recognizedfiveESI (3, 4,7,9, 1O) for the low tide; to the high tide the ESI number increased to seven (3, 4, 5, 7, 8, 9, 10). All these information are necessary to the decisions making about oi! spill and its derivatives containment. These techniques application makes possible the optimization and implantation ofnew socioeconomics activities of low environmental impact, indicates areas for better productivity and security exploration, and benefits local communities with fauna and flora preservation. The development of these activities is inserted in the scope of Monitoramento Ambiental de Áreas de Risco a Derrames de Petróleo e Seus Derivados Cooperation Project (Rede 05/01 - PETRORISCO, FINEP/CTPETRO/PETROBRAS) of multidisciplinary and interinstitucional characteristics dealing with subjects involving the environmental monitoring and the petroliferous activity

Caracterização geológica, geomorgológica e geotécnica de um corpo de dunas na cidade de Natal-RN

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Estudo integrado geológico/tecnológico de rochas ornamentais: os granitos flores e jacarandá, RN

The main purpose of the present study is to integrate a geological and technological investigation of ornamental rocks of the Flores and Jacarandá granites, which are located near the Afonso Bezerra city, in the north central part of the Rio Grande do Norte State. The study area encompasses four litho-stratigrafic units: a Gneiss-Migmatitic Complex(cristalline basement), which is mainly composed of banded gneisses, usually deformed as mylonitic rocks and with several migmatic features, an Augen Gneiss, which occurs as an elongated body that constitutes the Jacarandá granite, a small granite stock, which presents a semi-circular form, named Flores granite, composed of pink, fine to medium coarse rocks, and fine to coarse alluvial sediments, which form extensive areas of large fluvial deposits. The technological characterization of the Flores and Jacarandá granites, carried out through several tests, has as the main purpose the determination of petrographic, physical, and mechanic parameters that allowed the characterization of these rocks. The test followed procedures recommended by Brazilian (ABNT Associação Brasileira de Normas Técnicas) and foreigner institutions (ASTM American Society for Testing and Materials). The petrografhic analysis indicated that the rocks investigated are granite sensu estrictu, summing an average 85-90% modal. The Flores granite is the more felsic rock, which presents mafic content ∼ 10% and monzonitic composition. The Jacarandá granite is an Augen Gneiss rock that presents sienogranitic composition and mafic modal content ∼ 15%. Several technological tests carried out (alterability, physical indices, velocity of ultrasonic wave propagation, uniaxial compression, flection resistence, Amsler desgaste, and resistence to freezing and heating) indicated that parameters and values were identical for both granites investigated. These parameters and values are consistent with the Brazilian and international standards for siliciclastic rocks of ornamental use, as well as other Brazilian ornamental granites. The analysis of all results indicates that both the Flores and Jacarandá granites present good quality, and that they are indicated for ornamental use of revetment interior and exterior of buildings

Geologia e geomorfologia dos recifes de Maracajaú-RN e plataforma rasa adjacente

This work focuses the geological and geomorphological characterization of the inner shelf in the West Coast of the Rio Grande do Norte state, particularly the reef coral barrier offshore of Maracajaú (Maxaranguape district). If developed without the necessary concerns, tourism and entertainment activities that have been widely increased during the last five years can lead to irreversible environmental damages to the biotic and abiotic ecosystems of the region. Regarding these aspects, it is crucial the realization of a detailed study to envisage the achievement of a self-sustainable development, especially with respect to the possibilities of a rational usage of the region. This is the aim of this manuscript, which consisted of an initial stage of digital modeling of the terrain with basis on digitalization and vectorization of the Nautical map number 803 (Naval Service of Brazil, 1971). Information obtained in this phase was improved with the digital processing of small format aerial photos acquired from six flights, which were integrated to form a photomosaic of the area. The refined maps produced with the data from Nautical and aerial photo-interpretations aided to locate 9 bathymetric profiles, which provided information about the sea floor relief of the whole area. This later aided in the choosing of areas to bottom sampling that, in its turn, helped to characterize sediments present in floor of the inner shelf. Sixty-four samples collected during this work were studied by granulometrical and chemical analysis; with the later one developed in order to measure carbonate and organic matter contents. Forty-two of these samples showed carbonate content higher than 80% and organic matter in the range of 0.58% to 24.06%. With respect to grain size, these samples are in the interval between fine- to mid-grained sands. Sands with grain sizes higher than this one are also composed by carbonate carapaces such as pale yellow to red rhodolites with ellipsoidal and spheroidal shapes. During determination of the submerse features, the small format aerial photos demonstrated to be a useful methodology to aid the delineation of the sea floor topography through shallow deep waters. The bathymetry, for its turn, revealed several features at the bottom of the platform, in which the most conspicuous are undulations and morphological details of the São Roque Channel. Examination of bottom, aside from sand, yielded the identification of bivalves, ostracods, fragments of bryozoans, spikes of sponges, spines of echinoderms, operculum of gastropods and foraminifers. From the above it is concluded that the multi-methodological approach developed in this study worked efficiently, permitting the geomorphological and environmental characterization of the inner shelf of the North Maracajaú

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

Estruturação do grupo Serra Grande região de Santana do Acaraú- CE e a reativação do lineamento Sobral Pedro II, integração com dados geofísicos

The study area is located in the NW portion of the Ceará state nearby the city of Santana do Acaraú. Geologically it lies along the Sobral-Pedro II lineament which limits the domains of Ceará Central and Noroeste do Ceará, both belonging to the Borborema Province.The object of study was a NE trending 30km long siliciclastic body (sandstone and conglomerate) bounded by transcurrent dextral faults. The sediments are correlated to the Ipú Formation (Serra Grande Group) from the Parnaiba basin, which age is thought to be Siluro-Devonian. Existing structural data shown that bedding has higher but variable dips (70-45) near the borders faults and much lower to subhorizontal inward the body. The brittle deformation was related to a reactivation, in lower crustal level, of the Sobral-Pedro II lineament (Destro (1987, 1999; Galvão, 2002).The study presented here was focused in applying geophysicals methods (gravimetry and seismic) to determine the geometry of the sandstone/conglomeratic body and together with the structural data, to propose a model to explain its deformation. The residual anomalies maps indicate the presence of two main graben-like structures. The sedimentary pile width was estimated from 2D gravimetric models to be about 500-600 meters. The 3D gravimetric model stressed the two maximum width regions where a good correlation is observed between the isopach geometry and the centripetal strike/dip pattern displayed by the sediments bedding. Two main directions (N-S and E-W) of block moving are interpreted from the distribution pattern of the maximum width regions of the sedimentary rock

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 de processos morfodinâmicos e hidrodinâmicos do cinturão lacustre meridional da Reserva Biológica do Lago Pirituba, Amapá

The Amapá State has an important natural lake system, known as The Amapá Lakes Region . Most of these lakes are on the southern part of Amapá s coastal plain, which has 300 km of extension and it s composed by holocenic sediments deposited at the northern part of Amazon River to the Orange Cape located on the northern part of Amapá state. This region is under influence of the Amazon River discharge which is the largest liquid discharge of about 209.000 m³/s and biggest sediment budget discharged on the ocean in the order 6.108 ton per day. The climate is influenced by the Intertropical Convergence Zone and El Niño Southern Oscillation which act mainly under precipitation, nebulosity, local rivers and tidal hidrology. In this region lake belts are Ocidental, Oriental and Meridional Lake Belts. The last one is formed by the by the lakes Comprido de Cima, Botos, Bacia, Lodão, Ventos, Mutuco and Comprido de Baixo. These lakes are the closest to the Araguari River and are characterized by pelitic sedimentation associated with fluvial and estuarine flood plains under influence of tides. The lakes are interconnected, suffer influence of flood pulses from the Tartarugal, Tartarugalzinho and Araguari rivers and the hydrodynamic and morphodynamic know edge is poor. Volume and area reduction, natural eutrophication, anthophic influence, hidrodynamic alterations, morphological changes and are factors which can contribute to the closing of such lakes on the Meridional Lake Belt. This belt is inside the boundaries of the Biological Reserve of Piratuba Lake, created in 1980 for integral protection. Due to the fragility of the environment together with the poor knowledge of the system and with the study area relevancy it is necessary to know the hydrodynamic and geoenvironmental processes. This work aims the characterization of morphodynamic and hydrodynamic processes in order to understand the geoambiental context of the Meridional Lake Belt, from the Comprido de Baixo Lake to the dos Ventos Lake, including the Tabaco Igarape. Methodology was based on the hydrodynamic data acquisition: liquid discharge (acoustic method), tides, bathymetry and the interpretation of multitemporal remote sensing images, integrated in a Geographic Information System (GIS). By this method charts of the medium liquid discharges of Lake Mutuco and Tabacco Igarape the maximum velocity of flow were estimated in: 1.1 m/s, 1.6 m/s and 1.6 m/s (rainy season) and 0.6 m/s, 0.6 m/s and 0.7 m/s (dry period), the maximum flow in: 289 m³/s, 297 m³/s and 379 m³/s (rainy season) and 41 m³/s , 79 m³/s and 105 m³/s (dry period), respectively. From the interpretation of multitemporal satellite images, maps were developed together with the analysis of the lakes and Tobaco Igarape evolution from 1972 to 2008, and were classified according to the degree of balance in the area: stable areas, eutrophic areas, areas of gain, and eroded areas. Troughout analysis of the balance of areas, it was possible to quantify the volume of lake areas occupied by aquatic macrophytes. The study sought to understand the hydrodynamic and morphodynamic processes occurring in the region, contributing to the elucidation of the processes which cause and/or favor geoenvironmental changes in the region; all such information is fundamental to making the management of the area and further definition of parameters for environmental monitoring and contributing to the development of the management plan of the Biological Reserve of Lake Piratuba. The work activities is a part of the Project "Integration of Geological, geophysical and geochemical data to Paleogeographic rebuilding of Amazon Coast, from the Neogene to the Recent

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

Arquitetura, litofácies e evolução tectonoestratigráfica da bacia do rio do peixe, nordeste do Brasil

The Rio do Peixe Basin is located in the border of Paraíba and Ceará states, immediately to the north of the Patos shear zone, encompassing an area of 1,315 km2. This is one of the main basins of eocretaceous age in Northeast Brazil, associated to the rifting event that shaped the present continental margin. The basin can be divided into four sub-basins, corresponding to Pombal, Sousa, Brejo das Freiras and Icozinho half-grabens. This dissertation was based on the analysis and interpretation of remote sensing products, field stratigraphic and structural data, and seismic sections and gravity data. Field work detailed the lithofacies characterization of the three formations previously recognised in the basin, Antenor Navarro, Sousa and Rio Piranhas. Unlike the classical vertical stacking, field relations and seismostratigraphic analysis highlighted the interdigitation and lateral equivalency between these units. On bio/chrono-stratigraphic and tectonic grounds, they correlate with the Rift Tectonosequence of neocomian age. The Antenor Navarro Formation rests overlies the crystalline basement in non conformity. It comprises lithofacies originated by a braided fluvial system system, dominated by immature, coarse and conglomeratic sandstones, and polymict conglomerates at the base. Its exposures occur in the different halfgrabens, along its flexural margins. Paleocurrent data indicate source areas in the basement to the north/NW, or input along strike ramps. The Sousa Formation is composed by fine-grained sandstones, siltites and reddish, locally grey-greenish to reddish laminated shales presenting wavy marks, mudcracks and, sometimes, carbonate beds. This formation shows major influence of a fluvial, floodplain system, with seismostratigraphic evidence of lacustrine facies at subsurface. Its distribution occupies the central part of the Sousa and Brejo das Freiras half-grabens, which constitute the main depocenters of the basin. Paleocurrent analysis shows that sediment transport was also from north/NW to south/SE

Estudo da dinâmica costeira da região da foz do rio Piranhas-Açu para geração de mapas de sensibilidade do litoral ao derramamento de óleo

The study area is located in the northern coast of Rio Grande do Norte State comprising the mouth of Açu-Piranhas river including the cities of Porto do Mangue e Areia Branca. The local geological setting comprises Cretaceous, Tertiary and Quaternary geological units of the Potiguar Basin. One is about a region of high morphologic instability due to action of the rigorous dynamic coastal processes, beyond the intense human activities mainly for the performance of the petroliferous industry, salt farms and tanks of shrimp industry.For the accomplishment of this work Landsat 5 TM and Landsat 7 ETM + from four distinct dates were used as cartographic base, in which one applied techniques of digital processing to elaborate thematic maps of the existing natural resources to support the geologic and geomorphologic characterization and the soil and landuse maps. The strategy applied was the interpretation of multitemporal images from aerial and orbital remote sensors alIied to the terrain truth recognition, integrated through a Geographic Information System. These activities had alIowed the production of Sensitivity Maps of the Coast to Oil Spilling for the area, on the basis of the Coastal Sensibility Index. Taking into account the seasons were created maps to distinct datas: July 2003 represents the winter months that presented a sensibility lower when compared with the month of December 2003. For the summer months greater sensitivity is due to the hydrodynamic data that suggest a lesser capacity of natural cleanness of the oil and its derivatives in spilling case.These outcomes are an important and useful database to support an assessment to a risk situation and to taking decision in the face of an environmental disaster with oil spilling in coastal area, alIowing a complete visualization of the area and identifying all portions in the area with thei environmental units and respective Coastal Sensibility Index.

Caracterização Morfodinâmica e Sedimentologia da Plataforma Continental Rasa na APA Estadual dos Recifes de Corais - RN

This study had to aimed to characterize the sediments of shallow continental shelf and realize the mapping of features visible for satellite images by using remote sensing techniques, digital image processing and analysis of bathymetry between Maxaranguape and Touros - RN. The study s area is located in the continental shallow shelf of Rio Grande do Norte, Brazil, and is part of the Environmental Protection Area (APA) of Coral Reefs. A total of 1186 sediment samples were collected using a dredge type van veen and positioning of the vessel was made out with the aid of a Garmin 520s. The samples were treated In the laboratory to analyze particle size of the sediment, concentration of calcium carbonate and biogenic composition. The digital images from the Landsat-5 TM were used to mapping of features. This stage was used the band 1 (0,45-1,52 μm) where the image were georeferenced, and then adjusting the histogram, giving a better view of feature bottom and contacts between different types of bottom. The results obtained from analysis of the sediment showed that the sediments of the continental shelf east of RN have a dominance of carbonate facies and a sand-gravelly bottom because the region is dominated by biogenic sediments, that are made mainly of calcareous algae. The bedform types identified and morphological features found were validated by bathymetric data and sediment samples examined. From the results obtained a division for the shelf under study is suggested, these regions being subdivided, in well characterized: (1) Turbid Zone, (2) Coral Patch Reefs Zone, (3) Mixed Sediments Carbonates Zone, ( 4) Algae Fouling Zone, (5) Alignment Rocky Zone, (6) Sand Waves Field (7) Deposit siliciclastic sands

A erosão costeira e sua influência sobre a atividade petrolífera: alternativas sustentáveis na mitigação de impactos ambientais

The study area consist in high sensitivity environments located on the northern coast of Rio Grande do Norte, Northeast Brazil. The barrier island are the main geomorphological features on the coastal landscape, being naturally instable and surrounded by industrial activities like oil fields, salt industry, shrimp farms and urban areas sometimes installed parallel to the coast, combined with coast engineering interventions. High energy hydrodynamic process are responsible for the morphological instability of the coast. The study was based on remote sensing data obtained between 1954 and 2007 which consist in orbital images from Landsat, CBERS and Ikonos satellites and aerial photos. With all data integrated on GIS environment it was possible to update thematic maps of geology, geomorphology, vegetation, soil and landuse and development of multitemporal maps pointing areas with erosion and depositions of sediments, defining the critical erosion process on this region. The bigger morphological changes are related to changes on wind patterns during the year, terrestrial and sea breezes during the day, with spits and barrier island migration, opening and closing of channels like the one parallel to the coast on the area of Serra and Macau oil fields. These factors combined with the significant reduction on sediment budgets due to the loss of natural spaces to sediment reworking contribute to the low resilience which tends to be growing on the area of Serra and Macau oil fields. In front of such scenery a detailed monitoring was done in order to find technological possibilities for coastal restoration. A pilot area was defined to start the project of mangrove restore together with beach nourishment in order to minimize the effect of the erosion caused by the channel parallel to the coast, contributing to stabilize the northeast channel as the main one. It s expected that such methodology will aid the coastal environments restoration and the balance between industrial activities and coastal erosion