Caracterização multi-escalar de bandas de deformação nas tectonossequências paleozóica, pré- e sin-rifte da Bacia do Araripe, Nordeste do Brasil

Deformation bands are structures, developed in porous sandstones, that has small offsets and they are not shown on seismic section. The deformation bands of the pre and synrift sandstones of Araripe Basin were studied in outcrop, macroscopic and microscopic scales. The hierarchical, cinematic and spatial-geometric characteristics, and also the deformational mechanisms acting during its structural evolution were established too. In general, the mesoscopic scale observation allowed to discriminate deformation bands as singles or clusters in three main sets: NNE-SSW dextral; NE-SW normal (sometimes with strike-slip offset); and E-W sinistral; further a bed-parallel deformation bands as a local set. The microscopic characterization allowed to recognize the shearing and cataclastic character of such structures. Through the multi-scale study done in this work we verified that deformation bands analyzed were preferentially developed when sandstones under advanced stage of lithification. We also infer that the geometrical-spatial complexity of these bands, together with the presence of cataclastic matrix, can difficult the migration of fluids in reservoir rocks, resulting on their compartmentalization. Therefore, the study of deformation bands can aid researches about the structural evolution of sedimentary basin, as well as collaborate to understand the hydrodynamic behavior of reservoirs compartmented by these deformational structures

Caracterização geomorfológica e paleogeográfica da plataforma continental adjacente a foz do Rio Apodi-Mossoró, RN/Brasil

The brazilian marginal basins have a huge potential to generate and accumulate petroleum. Incised valleys which are eroded in response to a fall of relative sea level are related to potential reservoir as well, modern drowned-valley estuaries serve as harbors to petroleum and salt industries, fisheries, waste-disposal sites and recreational areas for a significant fraction of the world s population. The combined influence of these factors has produced a dramatic increase in research on modern and ancient incised-valley systems. This research is one expression of this interest. The integrated use of satellites images and high resolution seismic (bathymetry, sides scan sonar) was used on the Apodi River mouth-RN to characterizes the continental shelf This area is located at the Potiguar Basin in the NE Brazilian Equatorial Atlantic margin. Through bathymetric and side scan sonar data processing, a digital Terrain Model was developed, and a detailed geomorphologic analysis was performed. In this way was possible to recognize the geomorphologic framework and differents sismofacies, which may influence this area. A channel extending from the ApodiMossoró river mouth to the shelf edge dominates the investigated area. This structure can be correlated with the former river valley developed during the late Pleistocene sea level fall. This channel has two main directions (NW-SE and NE-SW) probably controlled by the Potiguar Basin structures. The western margin of the channel is relatively steep and pronounced whereas the eastern margin consists only of a gentle slope. Longitudinal bedforms and massive ridges also occur. The first are formed doe to the shelf sediment rework and the reef-like structures probably are relics of submerged beachrock-lines indicating past shoreline positions during the deglacial sea-level rise. The sub-bottom seismic data allow the identification of different sismic patterns and a marcant discontinuity, interpreted as the Upper

analise da dispersao de ondas de superficie na provincia borborema, Nordeste do Brasil

The Borborema Province, Northeastern Brazil, had its internal structure investigated by different geophysical methods like gravity, magnetics and seismics. Additionally, many geological studies were also carried out to define the structural domains of this province. Despite the plethora of studies, there are still many important open aspects about its evolution. Here, we study the velocity structure of S-wave in the crust using dispersion of surface waves. The dispersion of surface waves allows an estimate of the average thickness of the crust across the region between the stations. The inversion of the velocity structure was carried out using the inter-station dispersion of surface waves of Rayleigh and Love types. The teleseismic events are mainly from the edges of the South and North American plates. The period of data collection occurred between 2007 and 2010 and we selected 7 events with magnitude above 5.0 MW and up to 40 km depth. The difference between the events back-azimuths and the interstation path was not greater than 10. We also know the depth of the Moho, results from Receiver Functions (Novo Barbosa, 2008), and use those as constrains in inversion. Even using different parameterizations of models for the inversion, our results were very similar the mean profiles velocity structure of S-wave. In pairs of stations located in the Cear´a Central Domain Borborema the province, there are ranges of depths for which the velocities of S are very close. Most of the results in the profile near the Moho complicate their interpretation at that depth, coinciding with the geology of the region, where there are many shear zones. In particular, the profile that have the route Potiguar Bacia in inter-station, had low velocities in the crust. We combine these results to the results of gravimetry and magnetometry (Oliveira, 2008) and receptor function (Novo Barbosa, 2008). We finally, the first results on the behavior of the velocity structure of S-wave with depth in the Province Borborema

Análise da dinâmica deposicional das praias de Cacimbinha e do Madeiro, Tibau do Sul-RN, Brasil

The Cacimbinha and Madeiro beaches are located in the eastern coast of Rio Grande do Norte state, in the municipality of Tibau do Sul. Given the indicative of erosion in the coast of this district and the coastal processes acting on the beaches, the global aim of this project is comprehend the evolution of depositional environment on the Cacimbinha beach, moreover, the project seeks to characterize deposits from the Cacimbinha and Madeiro beaches, according to the geomorphologic compartments identified on these beaches; distinguish the coastal features which possibly interact with the Cacimbinha beach; identify the potential relationship between the sediments from the coastal features and the deposits from Cacimbinha beach; understand which depositional processes that prevail at each facies deposited on the beach; and identify the probable sedimentary environments and its energy of deposition through of the materials recorded on the Cacimbinha beach. This study was based on previous bibliographic and field research, both guided by academic works, laws, concepts and theories concerning the physical geography, geomorphology of the quaternary, sedimentary geology and stratigraphy. Thus, the methodology was divided in three steps: Prefield step: office work was performed; Field step: Sampling of facies of sedimentation; PosField step: analysis and integration of data obtained during the research period. Thus, the results showed deposicional facies with distinguished energy in the relief compartments, beach and terrace. After the sedimentary analysis and its interpretation linked to the architecture of the mounted sections based on drilling, it became possible to trace the evolutionary history of this stretch of beach. Therefore, it can be stated that studies performed on coastal areas are of great importance, as long as, around the world, the most part of urban zones are seated on deposits of quaternary age and, then this work improve the knowledge regarding the sedimentary dynamics of this beach, becoming scientific support for management and planning of this area which focus on, mainly, the foreign tourism

Estudo de viabilidade técnico-ambiental para implantação de parques eólicos: um estudo de caso em um fragmento do litoral setentrional do Rio Grande do Norte/Brasil

The use of energy from renewable sources is increasingly demanded by society, especially aeolian - whose raw material is wind. Investments in wind power have become significant in Brazil with emphasis on the Northeast and in particular the Rio Grande do Norte state. According to the Empresa de Pesquisa Energética (Energy Research Company) (2012 ) , investments in the state grew significantly since 2002 with a total accumulated power, by 2013, of approximately 3,400 MW . Even with the early experiences of exploitation of wind energy in 2002, it is still considered new and requires further study referring to the likely changes in the environment and society. In this case, it is of growing and urgent importance to deeply study the wind still in the survey phase of the project, ie , at the beginning of decision making on the most feasible to implement these parks site. Given the above, the question is: from a technical and environmental analysis, how to identify viable areas to install Aeolian parks, taking into account the factors of the environmental dynamics that are relevant to minimize the negative results to the environment and the society? Thus, this study conducted a study on technical and environmental feasibility, proposing a methodology of exploration of feasible wind farms in coastal areas. The study area was a fragment of the northern coast of Rio Grande do Norte and its natural landscape units were identified through the environmental characterization of the area, as well as it was elaborated the map of the land cover, restriction homes and urban areas and Permanent Preservation Areas - PPAs. The environmental fragility was subdivided in the fragility of the natural dynamic, mapped through relief, soils and geology of natural units, and the fragility of the ecosystem, originated by the land cover map. In addition to these maps, it was generated the wind resource for an area from a height of 50 and 100 meters. The intersection between the fragility maps, PPAs and Restriction of homes superimposed on maps of wind potential, provided the map of feasibility of Aeolian parks, resulting in the most favorable areas for its facilities in a technical and environmental point of view. From this study, the entrepreneur can evaluate whether or not to proceed with the studies in this area and especially decrease potential conflicts with society.