Navegando por Assunto "Mapeamento geológico"

Agora exibindo 1 - 13 de 13

Acesso aberto (Open Access)
Análise crítica das metodologias gerais de mapeamento geotécnico visando formulação de diretrizes para a cartografia geotécnica no trópico úmido e aplicação na região metropolitana de Belém escala 1:50.000
(Universidade Federal do Pará, 2001-11-09) COSTA, Tony Carlos Dias da; ABREU, Francisco de Assis Matos de; http://lattes.cnpq.br/9626349043103626; GANDOLFI, Nilson; http://lattes.cnpq.br/2605833412394930
This thesis brings within its scope the critical analysis of the main national and international methodologies of geotechnical cartography (IAEG, Australian, French, EESC-USP, IPT, IG-UFRJ and IG-SP), as well as the classification of a set of rules for the elaboration of geotechnical maps and charts in the Brazilian Humid Tropics. It also presents geotechnical mapping at the scale of 1:50 000, of the Metropolitan Region of Belém, in the State of Pará, comprising the municipalities of Belém, Ananindeua and Marituba. The methodology is based on the above-mentioned cartographic (conventions/ rules), and is presented in the form of eleven cartographic items: a documentary map of the Metropolitan Region of Belém, at a scale of 1:50 000; a documentary map of the central area of Belém, at a scale of 1:10 000; a gradient map; a geological map; a map of unconsolidated materials; a soil use map; a map of institutional areas and conservation units; a map of floodplain and mainland areas; a map of zones of permanent protection of water bodies; a chart of the preferential areas for the exploration of natural construction materials; and a chart of the preferential areas for the installation of sanitary landfills.
Acesso aberto (Open Access)
Análise de imagens de sensores remotos orbitais para mapeamento de ambientes costeiros tropicais e de índices de sensibilidade ambiental ao derramamento de óleo no Golfão Maranhense
(Universidade Federal do Pará, 2006-04-18) TEIXEIRA, Sheila Gatinho; SOUZA FILHO, Pedro Walfir Martins e; http://lattes.cnpq.br/3282736820907252
The oil spills in Brazil are more and frequents, causing several impacts on environments and biological communities. Envronmental sensitivy index maps of oil spils are indispensbles components of contingency and emergency answer plans for this tpe of accident. These maps present a system of classification based on geomorphologic characteristics of the áreas, which are defined by the following factors: wave and tidal energy exposure relative degree, shoreline slope and substrate type, and also, the easiness to clean and remove the oil impacted áreas. In this contect, the “Golfão Maranhense” region, located on Northern “Maranhão” State, was chosen in order to map and analyze the environmental sensitivity indexes (ESis) of oil spills on coastal environments, for in this área, we find the second largest port in draught of the world, the Porto f “Itaqui”. Moreover, this region is the route of six hundred oil tankers per year, which are potential agents that cause the oil spill. The methodological approach for creating the maps of environmental sensitivity index included the integrated analysis of coastal environments based on digital image processing from remote optical sensores, in this case, Landsat-4TM, CBERG-2 CCD and SPOT-2 HRV, SAR (Synthetic Aperture Radar) images from RADARSAT-1 Wide 1, SRTM (Shuttle Radar Topography Mission) elevation data, geographic information system and Field surveys related to geomorphology, topography and sedimentology. Using the aforementioned methods, the coastal environments recognized in “Golfão Maranhense” were grouped according to their envronmental sensitivity index: 1 – Solid men-made structures (ESI 1B); 2- Cliffs (ESI 1C); 3 – Fine grained sand beaches and móbile dunes (ESI 3ª); 4- Tidal sandflats (ESI 7); 5- Mixed intertidal Banks, tidal mudflats and ebb-tidal delta (ESI 9ª); 6- Supratidal sandflat (ESI 9C); 7- Saltmarshes (ESI 10ª); 8- Fresh marhes and intermittent lakes (ESI 10B) and 9- Mangrove (ESI 10C). This approach is efficient to recognize and analyze coastal environments and, therefore, it pernitted the sensivity index attribution for the oil spill on yhese environments, in a georefenced data base, which allows making faster e more efficiently decisions in case oil spills come to happen.
Acesso aberto (Open Access)
Aplicação de dados multisensor (SAR e ETM+) no reconhecimento de padrões de uso e ocupação do solo em costas tropicais: Costa Amazônica, Amapá, Brasil
(2009) SANTOS, Valdenira Ferreira dos; POLIDORI, Laurent; SILVEIRA, Odete Fátima Machado da; FIGUEIREDO JÚNIOR, Alberto Garcia de
Environmental studies require information on land use and land cover. This paper presents the applicability of multi-sensor satellite data (optical and radar) for land use and land cover on the Amapá coastal plain for mapping and recognition of natural and anthropogenic dynamics. This area is influenced by the Amazon River, by tides (tidal bore) and by the Intertropical Convergence Zone (ITCZ). Anthropogenic processes are associated with water buffalo ranching. The environmental information was acquired from previous data and field observation and was correlated with remote sensing data (JERS-1, RADARSAT-1, image from ETM+ sensor from Landsat 7 and DEM SRTM), digitally processed for multi-sensor, multi-scale and multi-date approach. Eight patterns of land use and land cover were identified (mangrove, "várzea" forest, arbustive vegetation area, freshwater marsh, anthropic field, intertidal plain, estuarine channel and lakes) as well with indication of natural and anthropogenic geomorphic features. The results from the evaluation of remote sensing data and the techniques applied demonstrated the potential of the remote sensing tool for studying environments in highly dynamic tropical coastal areas of difficult access. However, these tools may present some limitations once applied to application to the Amazon coast, which is a region under strong dynamic natural and anthropogenic processes.
Acesso aberto (Open Access)
Basaltos almofadados da Suíte Ofiolítica Morro do Agostinho: registros de fundo oceânico na porção centro-oeste do Cinturão Araguaia
(2013-12) MIYAGAWA, Luciana de Jesus Penha Pamplona; GORAYEB, Paulo Sérgio de Sousa
Along the domain of low metamorphic grade (Midwestern portion) of the Araguaia Belt, outcrop dozens mafic and/or ultramafic bodies of ophiolitic suites. An example is the Morro do Agostinho Ophiolite Suite, in the surroundings of the city of Araguacema (Tocantins) that configures a small isolated body that sustains the Morro do Agostinho and is tectonically emplaced in meta-sandstones, slates and phyllites of Couto Magalhães Formation (Tocantins Group). The Morro do Agostinho Ophiolite Suite consists of serpentinized peridotites, basalts and ferriferous cherts. The association of basalts is characterized by a significant layer of submarine pillow lavas overlying serpentinized peridotites. The basalts were classified into massive and hialobasalts types. Massive basalts are homogenous, with intersertal texture that is essentially composed of thin laths and acicular crystals of plagioclase and clinopyroxene and present rare crystals of olivine, chalcocite and chalcopyrite. Hyalobasalt shows ultra-fast cooling features (quenching) as spherulites, radial, acicular and skeletal crystals of plagioclase and clinopyroxene with forms of swallowtail. Geochemical data, including (La/Yb)n and (La/Sm)n ratios less than 1, indicate a subalkaline-tholeiitic MORB nature of the basalts. These rocks show that during the geological evolution of Araguaia Belt, there was an oceanization stage of Araguaia Basin, with litospheric mantle's exposure, followed by lava's extravasation and sedimentation of cherts and banded iron formation in deep ocean environment. After sedimentary filling of the Couto Magalhães Formation (Tocantins Group), the tectonic inversion, which led to the exhumation of the ophiolitic bodies, especially along thrust surface, with fragmenting and tectonic mixing with supracrustal rocks, accompanied by regional metamorphism under conditions of low green schist facies. The Morro do Agostinho Ophiolite Suite therefore represents a small allochthonous fragment of a well-preserved ocean mantle/crust lithosphere, similar to the others examples found in the Araguaia Belt who marks the Araguaia Basin's moment of oceanization during the Neoproterozoic.
Acesso aberto (Open Access)
Costa de manguezais de macromaré da Amazônia: cenários morfológicos, mapeamento e quantificação de áreas usando dados de sensores remotos
(2005-12) SOUZA FILHO, Pedro Walfir Martins e
De acordo com o Atlas de Manguezais, este ecossistema representa 8% de toda a linha de costa do planeta e um quarto da linha de costa da zona tropical, perfazendo um total de 181.077 km2. Este trabalho objetiva quantificar a extensão dos manguezais de macromaré da costa nordeste do Pará e noroeste do Maranhão, aqui denominada de Costa de Manguezais de Macromaré da Amazônia (CMMA). O reconhecimento das áreas de manguezais e sua quantificação foram realizados a partir da utilização de imagens Landsat-7 ETM+, adquiridas em 1999 e 2000 e de um sistema de informações geográficas (SIG). A integração dos dados de sensores remotos, dados geológicos e oceanográficos permitiu o reconhecimento de cinco setores geomorfológicos, que abrangem uma superfície total de 7.591 km2 de manguezais. Esta área representa a maior faixa de manguezais contínuos do planeta e corresponde a 56,6% dos manguezais do Brasil. Medidas prioritárias de conservação dos manguezais da Amazônia devem ser tomadas e pesquisas que busquem a melhor compreensão deste complexo e importante ecossistema devem ser financiadas e desenvolvidas.
Acesso aberto (Open Access)
Environmental sensitivity index (ESI) mapping of oil spill in the amazon coastal zone: the PIATAM Mar project
(2009) SOUZA FILHO, Pedro Walfir Martins e; PROST, Maria Thereza Ribeiro da Costa; MIRANDA, Fernando Pellon de; SALES, Maria Emília Cruz; BORGES, Heloisa Vargas; COSTA, Francisco Ribeiro da; ALMEIDA, Edson Faria de; NASCIMENTO JUNIOR, Wilson da Rocha
The importance of environmental monitoring is clear from the many oil spills that have occurred over the past three decades. This has encouraged both companies and the public sector involved in the prevention and response to these accidents to develop efficient procedures to minimize the damage caused by accidents involving oil spill. This study reviews the history of oil spill accidents in Brazil and examines how these events have contributed to the development of technological research through partnerships involving oil companies, government, universities and research institutes, with the emphasis on the Amazon coastal zone. As a result, environmental sensitivity indexes (ESIs) for oil spill have been developed specifically for the Amazon coast, where fluvial and marine processes take place in the estuary of the world's largest river system. Perspectives on research and emergency response procedures are presented, with the primary objective of conserving the social-environmental diversity of the planet's most important tropical region.
Acesso aberto (Open Access)
Fusão de dados multisensor para a identificação e o mapeamento de ambientes flúvio-estuarinos da Amazônia
(2009) GONÇALVES, Fabrício Dias; SOUZA FILHO, Pedro Walfir Martins e; PARADELLA, Waldir Renato; MIRANDA, Fernando Pellon de
Multisensor data fusion has been widely used in response to complementary nature of many data sets. This paper compares the results of four different data fusion methods used to merge Landsat-7 ETM+ and RADARSAT-1 Wide 1 data. The comparison was based on spectral characteristics of images using statistical and visual analyses of generated products. Four methods were used in the Landsat-7 ETM+ and RADARSAT-1 W1 data fusion: i) The best three bands combination(Landsat-7) based OIF (Optimum Index Factor) selection were merged with RADARSAT-1 data; ii) Decorrelation stretch was applied in the three bands (Landsat-7) selected by OIF and merged with RADARSAT-1 image; iii) PCA (Principal Component Analysis) to six reflective ETM+ bands (1, 2, 3, 4, 5 and 7) and posterior fusion of the three first Principal Components (PC1, PC2, PC3) with SAR; iv) A new approach SPC-SAR (Selective Principal Component - Synthetic Aperture Radar). The SPC-SAR product presented the best performance in the identification of coastal features and allowed the most effective enhancement of the different environments.
Acesso aberto (Open Access)
Mapeamento de ambientes costeiros tropicais (Golfão Maranhense, Brasil) utilizando imagens de sensores remotos orbitais
(2009) TEIXEIRA, Sheila Gatinho; SOUZA FILHO, Pedro Walfir Martins e
This paper presents the results of coastal environmental mapping of Golfão Maranhense, Brazil, using a methodological approach that includes: (a) integrated analysis based on digital image processing of Landsat-4 TM, SPOT-2 HRV, RADARSAT-1 SAR (Synthetic Aperture Radar) and SRTM (Shuttle Radar Topography Mission) data; (b) geographic information system; (c) field surveys related to geomorphology, topography and sedimentology. Mapped environments were grouped into four sectors: Sector 1, with salt marsh, fresh marsh, estuarine channel and intermittent lake; Sector 2, embracing coastal plateau, fluvial floodplain, sandflats, macrotidal beach, urban areas, artificial lakes and mudflats; Sector 3, including, paleodunes covered with grass, mangroves and mixed intertidal banks; Sector 4, constituted by mobile dunes. In addition, perennial lakes, ebb-tidal deltas and supratidal sandflats were recognized. Digital image processing visual analysis of orbital remote sensing data in association with geographic information system, proved to be effective in tropical coastal mapping, allowing the generation of products with good accuracy and cartographic precision.
Acesso aberto (Open Access)
Mapeamento de magnetização aparente usando regularização entrópica
(Universidade Federal do Pará, 2007) VASCONCELOS, Suzan Sousa de; SILVA, João Batista Corrêa da; http://lattes.cnpq.br/1870725463184491
We present a new apparent-magnetization mapping method on the horizontal plane that combines the minimization of the first-order entropy with the maximization of the zeroth-order entropy of the estimated magnetization contrasts. The interpretation model is a grid of vertical, juxtaposed prisms in both horizontal directions. We assume that the top and the bottom of the magnetic sources are flat and horizontal and estimate the prisms' magnetization contrasts. The minimization of the first-order entropy favors solutions presenting sharp borders, and the maximization of the zeroth-order entropy prevents the tendency of the source estimate to become a single prism. Thus, a judicious combination of both constraints may lead to solutions characterized by regions with virtually constant estimated magnetization contrasts separated by sharp discontinuities. We apply our method to synthetic data from simulated intrusive bodies in sediments that present flat and horizontal tops. By comparing our results with those obtained with the smoothness constraint, we show that both methods produce good and equivalent locations of the sources' central positions. However, the entropic regularization delineates the boundaries of the bodies with greater detail. Both the proposed and the smoothness constraints are applied to a real anomaly over a magnetic skarn in Butte Valley, Nevada, USA. The entropic regularization produced an estimated magnetization distribution with sharper boundaries, smaller volume, and higher apparent magnetization as compared with the results produced by the smoothness constraint.
Acesso aberto (Open Access)
Métodos geofísicos aplicados ao mapeamento geológico numa área da Região Bragantina-Pará
(Universidade Federal do Pará, 1979-12-13) FERREIRA, João Batista; SAUCK, William August; http://lattes.cnpq.br/6655455534234531
The following research is about the aplication of geophysical methods in a pilot area in the Bragantina region, NE of Pará, as an auxiliary to geologic mapping. The area is covered with thick tertiary sediments and presents occurrences of industrial rocks such as limestone and granite, representing an outcrop surface smaller than 5% of area. Studies carried out by Goulart (1978) revealed that it is impossible to determine parent rock of the superficial material, of the A horizon. This makes difficult the surface geologic mapping and can lead to exaggerated extrapolation of the contacts, such as that which took place in the preliminary mapping. The geophysical methods applied in the area are: Electroresistivity and Magnetometry. Some mechanical sounding was carried out also. The results obtained contributed to a better understanding of the structural features mapped, and also made it possible to discover other important features. Two areas were defined for future detail study, with the objective to distinguish between the limestones of better and poorer quality. In reference to the granite region a new mapping of that area is suggested.
Acesso aberto (Open Access)
Reconhecimento e mapeamento dos ambientes costeiros para geração de mapas de ISA ao derramamento de óleo, Amazônia oriental
(2009) BOULHOSA, Messiana Beatriz Malato; SOUZA FILHO, Pedro Walfir Martins e
Accidents related to exploration and oil transport are a threat to coast zones around the world. Oil spills are an ecological disaster that may cause irreparable damage to the environment. In the northeast cost of Pará state the intense flow of ships and rafts transporting petroleum and flowed, then the need to establish prevention strategies and administration of the environmental sensitivity about the oil spills in a certain part of Pará state northeast cost. The methodology consisted on processing digital images from remote sensors in the Landsat ETM+7 associated to data from the SRTM (shuttle radar topography mission) digital model of elevation, and to the field data collected in a GIS (geographical information system) environment. The most important results allowed: recognizing and describing five main geomorphological; identifying and classifying nine units of Environmental Sensitivity Rates (ISA) and creation of the Environmental Sensitivity Rates map to oil spill. The remote sensors techniques and SIG proved to be important tools for recognizing coast environments and for generating proposed maps.
Acesso aberto (Open Access)
Tratamento estatístico de dados geoquímicos e sua aplicação ao mapeamento geológico e definição de anomalias geoquímicas no alvo 2 - corpo 4 - Província Mineral de Carajás
(Universidade Federal do Pará, 1982-12-29) MOURA, Candido Augusto Veloso; RAMOS, José Francisco da Fonseca; http://lattes.cnpq.br/8189651755374537
A geochemical soil survey was .carried out in the Alvo 2 - Corpo 4 area of t.he Província Mineral de Carajás (Carajas Mineral Province), Pará, Brazil. Sample elements were collected and analyzed in order to determine, for each one of them, the degree of concentration of the following chemical elements: iron, aluminum, magnesium, manganese, titanium, cobalt, nickel, vanadium, copper, and zinc. Thereafter, multivariate statistical techniques were employed to process the data, that are known as cluster analysis and discriminant analysis. The former algorithm was applied in order to classify the elements of the soil sample into geochemically homogeneous groups that could be correlated with underlying lithologies. A discriminant analysis was then per formed to statiscally evaluate the distinctiveness of groups arrived at, and at the same-time to define those chemical elements which were most determinant throughoot the discriminatory process. Cluster analysis classified the soil sample elements into eight homogeneou groups that are perfectly correlated with underlying rocks. Discriminant analysis showed that results of the cluster are good, and only titanium and zinc do not play an important role in discriminating the groups arrived at. The results obtained show that the multivariate statistical processing of geochemical soil data can be used successfully as a useful tool when mapping the geology of tropical areas. Finally, an examination of Pearson correlation coefficients, scatter diagrams and residuals from regression analysis, allowed to explore the possible effect of hydrous iron and manganese oxides and of clay minerals (extra-mineralization factors), in producing the copper and zinc anomalies revealed by the geochemical soil survey, originally. Concentrations of hydrous iron and manganese ox ides and of clay minerals were correlated with concentrations of iron, manganese and aluminum in the soil. The Pearson correlation coefficients and the scatter diagrams of copper, and then of zinc, with iron manganese and aluminum, as well as the reduced major axis regression line of copper on iron, indicated that high, grades of copper and zinc found in the soil sample of Alvo 2 - Corpo 4 are not affected by the extra-mineralization factors considered. Therefore, it is conclude that it is the sulphide mineralization present in the study area that can be held responsible for those high concentrations of copper and zinc.
Acesso aberto (Open Access)
Use of synthetic aperture radar for recognition of Coastal Geomorphological Features, land-use assessment and shoreline changes in Bragança coast, Pará, Northern Brazil
(2003-09) SOUZA FILHO, Pedro Walfir Martins e
Synthetic Aperture Radar (SAR) images are being used more extensively than ever before for geoscience applications in the moist tropics. In this investigation, a RADARSAT1-1 C-HH SAR image acquired in 1998 was used for coastal mapping and land-cover assessment in the Bragança area, in the northern Brazil. The airborne GEMS 1000 X-HH radar image acquired in 1972 during the RADAM Project was also used for evaluating coastal changes occurring over the last three decades. The research has confirmed the usefulness of RADARSAT-1 image for geomorphological mapping and land-cover assessment, particularly in macrotidal mangrove coasts. It was possible to map mangroves, salt marshes, chenier sand ridges, dunes, barrier-beach ridges, shallow water morphologies and different forms of land-use. Furthermore, a new method to estimate shoreline changes based on the superimposition of vectors extracted from both sources of SAR data has indicated that the shoreline has been subjected to severe coastal erosion responsible for retreat of 32 km2 and accretion of 20 km2, resulting in a mangrove land loss of almost 12 km2. In an application perspective, orbital and airborne SAR data proved to be a fundamental source of information for both geomorphological mapping and monitoring coastal changes in moist tropical environments.