Navegando por Assunto "Sensoriamento remoto - Carajás, Serra dos (PA)"

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Acesso aberto (Open Access)
Análises texturais de produtos derivados de LiDAR para discriminação de cangas lateríticas, Serra Sul de Carajás (PA)
(Universidade Federal do Pará, 2016-09-30) SANTOS, Jaqueline Alcântara dos; SILVA, Arnaldo de Queiroz da; http://lattes.cnpq.br/1682623730626187; SOUZA FILHO, Pedro Walfir Martins e; http://lattes.cnpq.br/3282736820907252
The characterization of geological features through products derived from remote sensing in humid tropical regions suffers severe restrictions due to the influence of vegetation on the radiometric measurements. This is the motivation to investigate new methodological approaches aimed at extracting remote sensing information data applied to geological mapping. This research aimed to develop a methodological approach to discriminate types of lateritic surfaces from textural parameters of the Haralick extracted shaded relief image generated Digital Model Land of high spatial resolution (1 m) derived from the last return signal (ground) of LiDAR data. The study area is located in body S11CD in Serra Sul of Carajás Mineral Province, including the city of Canãa dos Carajás (Pará State - Brazil). The body S11CD is characterized by a residual relief supported by ferruginous crust thick developed on Archean banded iron formations (Carajás Formation / Grão Pará Group) and is covered by savannah (campus rupestres) that contrast with the surroundings tropical rain forest. The lateritic crust in the study area is classified into (1) structural duricrust and (2) detrital duricrust. The difference between the types of lateritic crust was analyzed by microtopography relief metrics (Hrms), measured in the field and textural parameters of the Haralick extracted from the shaded relief image. Statistical tests of averages Hrms comparison (Student t test) showed that it is possible to identify the terrain microrugosidade kinds of lateritic duricrust present in S11CD. The object-oriented classification (GEOBIA) was used dissimilarity textural parameter of the Haralick to discriminate the types of lateritic duricrust. For this, it was used the standard deviation of the average dissimilarity threshold for separating the detrital duricrust (26.1 ↔ 33.234) and structure duricrust (20.573 ↔ 28.515). The result of this classification overlaid around 89.35% the study area, remaining ~ 11% of the image not classified, possibly as a result of noise in the LiDAR data. The validation of this classification attested that the overall accuracy of field data and the classification was 78.8%. Note also, that the structural duricrust occurs in the area as small "windows" through the detrital duricrust, which made it difficult to carry out field sampling at this site, so the errors of commission and of omission become high.
Desconhecido
Uso de lidar aerotransportado para mapeamento e análise estrutural de depósitos ferríferos na serra sul de Carajás, Amazônia
(Universidade Federal do Pará, 2018-03-29) COSTA, Francisco Ribeiro da; SOUZA FILHO, Pedro Walfir Martins e; http://lattes.cnpq.br/3282736820907252
This research is focused on the definition of methods for the use of Light Detection And Range - LiDAR data in structural geological mapping. In the Amazon Region, in particular in the banded iron formations of the Mineral Province of Carajás - PMC, the vegetal cover compromises the extraction of structural information from optical remote sensing data, since it masks the geomorphological and structural features that can correspond the geological structures . This thesis addressed the application of digital image processing techniques of LiDAR data, from i) shaded relief model - MRS do, which used a configuration with eight lighting modes with different views ranging from 45º between them, to generation of alignment maps; and ii) laplacian filtration in shaded relief model - FLMRS in multidirectional visions. In both resulting maps the same structural trends, NE-SW, NW-SE and secondarily N-S and E-W were observed. However, the map generated from the FLMRS in multidirectional visions presented a better geometry of the spatial distribution of the lineaments. The results obtained from the analysis of LiDAR data were compared with structural data collected and analyzed from the study of iron ore deformation and associated volcanic rocks at the Serra Sul de Carajás mine - S11D. The structural analysis showed a single episode reflecting shortening in the E-W direction, with the installation of two fault systems, one NE-SW direction and the new NW-SE direction. This deformation is responsible for the geometry of the rocks of the S11D plateau, forming a sinformal / antiformal sequence with NE and SE trim along with these fault systems and with axial planes dipping at high angles to NW and NE forming folds with complex interference patterns. Lamination in iron ore still preserves primary structures and there is no evidence of pervasive milonization in these rocks. It proposes a deformational model for the rocks of the S11D Plateau related to transpression controlled by the Carajás Fault during regional sinistral movements. The comparative analysis of the structural maps generated with airborne LiDAR data and traditional manual methods were performed from the comparative of the two maps. The calculation and quantification of the dispersion of the structural contour lines in each area from the different methods showed a correlation coefficient that varied between 0.91 and 0.93, suggesting a good degree of similarity between the mapped structures, although there are variations in the orientation and abundance in the structural contour lines. In general, the results demonstrate the effectiveness of the airborne LiDAR data to extract detailed and accurate structural information on tropical terrain and can be used to complement the fieldbased structural mapping.