Paulo Pereira Martins Junior

Mapping iron-mineralized laterite environments based on textural attributes from MAPSAR image simulation - SAR-R99B (SIVAM/SIPAM) in the Amazon region

The use of remote sensing is a valuable method for geological mapping as it provides synoptic coverage at relatively low cost. In the Amazon region, radar imagery has a potential for geological applications due the enhanced sensitivity to topography (macrotopography), surface roughness (microtopography), and dielectric properties of materials, independent of weather, sun angle, and illumination conditions. As the roughness is highlighted, SAR textural attributes can be used for mapping iron-ore mineralized laterites in N1 deposit, located in the Carajas Province. For mapping the lateritic cover, the airborne SAR was used from Surveillance of the Amazon System (SIVAM/SIPAM, L-hh, L-hv, L-vv) to simulate orbital Multi-Application Purpose SAR (MAPSAR). The images were analyzed through textural classifications derived from second-order measure (GLCM) with the objective of mapping the mineralized laterites for iron ore. Differences are highlighted when comparing the classified maps and the ground information. Not all classes were separated, but a high performance for textural attributes was presented by the hematite class. This class was sensitive to the sensor and target parameters, especially macrotopography and physics characteristics. The results showed that for mineral exploration, the radar images at L-band can be used as a practical tool for a preliminary mapping, and as a guide for field-based verification.

Multi-scale approach using remote sensing images to characterize the iron deposit N1 influence areas in Carajás Mineral Province (Brazilian Amazon)

Mining activities cause a wide range of changes to the environment, substantially affecting both the physical and biological environmental sectors. In the Carajás Mineral Province, located in the Amazon rainforest, environmental regulations tend to be more rigorous, due to the fragility of the environment in which large iron deposits are found. The characterization of the impact of mining on environment considers: the type and extent of the impact, the physical chemistry differences and similarities of the mineral deposits, the deposit size, the adopted mining process, and the environment (both natural and economic) in which the mining process was developed. Remote sensing technology is utilized in this study, in particular, the use of ortho-aerial photograph, and optical and radar images with distinct spatial resolution. These permit the elaboration in synoptic maps, multi-scale and dynamic, of the changes wrought upon the environment: deforestation, removal of vegetation cover, topographic surface and landscape alteration, and slope instabilities among others. In this aspect, determining the extent of influence of the mining activity is directly tied to the characterization of its impact on various natural systems at the observed scale, and not by simply defining a predetermined Euclidean distance. The results showed that remote sensing technology, optical and radar images, proved to be efficient in the study of environmental information and the areas of influence on the semi-regional and local scales in the Amazon forest.

Hydrographic and hydrogeological basin of Entre-Ribeiros: probable recharge zone delimitation and environmental impact assessment

The probable recharge zone delimitation of Entre-Ribeiros Basin (Northwest of the state of Minas Gerais / Brazil) is proposed in this study. The delimitation is based upon stratigraphy, geomorphology, geo-environmental domains and hydrogeology studies. Combining the recharge zone map with the land use variation between 1975 and 2008, the occupation trends of possible recharge zones are identified. Concluding, the environmental impacts for this basin are discussed.

Analysis of spatial–temporal patterns of water table change as a tool for conjunctive water management in the Upper Central Plain of the Chao Phraya River Basin, Thailand

A sustainable strategy for conjunctive water management must include information on the temporal and spatial availability of this natural resource. Because of water shortages in the dry seasons, farmers on the Upper Plain of the Chao Phraya River basin, Thailand, are increasingly using groundwater to meet their irrigation needs. To evaluate the possibilities of conjunctive water management in the area, the spatial–temporal changes in the water table of the Younger Terrace Aquifer were investigated. First, a regional geomorphological map based on field surveys, remote sensing and previous environmental studies was developed. Then, the well data were analyzed in relation to rainfall, streamflow, yield and pumpage, and the data were interpolated using geostatistical techniques. The results were analyzed via integrated zoning based on color theory as applied to multivariate visualization. The analysis results indicate areas that would be more suitable for groundwater extraction in a conjunctive management framework with regard to the natural hydrogeological processes and the effects of human interaction. The kriging results were compared with the geomorphological map, and the geomorphological areas exhibit distinct hydrogeological patterns. The western fans exhibit the best potential for the expansion of conjunctive use, whereas the borders of the northern fans exhibit the lowest potential.

Estimation of flow components by recursive filters: case study of Paracatu River Basin (SF-7), Brazil

The quantification of flow components is important for water resource management. The base, interflow, and runoff flows of nested basins of the Paracatu River (SF-7) were estimated with recursive signal filters in this study. At first, stationary analysis and multivariate gap filling were applied to the flow data. A methodology is presented, proposing filter calibration with the runoff influence and inflection of the recession curve for dry season. Filters are improved with a logic constraint that limits water flow overestimation within algorithm iteration. The results were coherent with previous studies and with hydrogeological and climatological maps.

Metodologia para diagnóstico rápido de áreas de recarga de aquíferos

The environmental tools of local appliance, such as surveillance and permits of deforestations and water use, environmental impact assessments of local scale, and delimitation of preservation areas, demand customized methodologies to deal with hydrogeological issues. In this study, a structured one for rapid environmental assessment aiming at recharge of aquifers safety was presented. This comprises qualitative and quantitative evaluations by means of textual and cartographical descriptions, complemented by weighted spreadsheets for rapid assessment. Applications in case studies took place in sites selected in the Paracatu River Basin. The results showed a positive potential for knowledge and protection of aquifers in micro-watersheds.

Arquitetura de conhecimentos sobre sistemas aquíferos

Apresenta-se a metodologia de Organograma de Rodas de Correlacoes e Impactos – ORCI – como instrumento em contextos de elicitacao e formalizacao de conhecimentos. Toma-se como estudo de caso o conhecimento sobre pesquisa e gestao de sistemas aquiferos, no âmbito do Projeto Gestao de Zonas de Recarga de Aquiferos Partilhadas entre as Bacias de Paracatu, Sao Marcos e Alto Paranaiba – GZRP, financiado pela Fapemig (2007-2009). Propoe-se a construcao de portais digitais de informacao para potencializar as metodologias utilizadas, bem como para interconectar os produtos obtidos a outras plataformas, metodologias e linguagens de Tecnologia da Informacao.

PERDA UNIVERSAL DE SOLOS PARA A REGIÃO DO ALTO MÉDIO SÃO FRANCISCO - MINAS GERAIS

O principal objetivo deste trabalho foi buscar estimar a perda universal de solos em uma localidade situada na regiao do alto medio Sao Francisco, no Estado de Minas Gerais, combinando-se o uso dos Sistemas Informacoes Geograficas (SIG) com modelo quantitativo da Equacao Universal de Perdas de Solos (USLE). Neste caso esta localidade foi dividida em duas partes, e atraves da avaliacao da degradacao ambiental, estudou-se a parcela mais degradada, considerando, neste caso, a perda de vegetacao nativa (cerrado) como fator de distincao entre ambas as partes territoriais. Usando a ferramenta do software SPRING/INPE e o ArcGIS, estimou-se a perda de vegetacao nativa ao longo dos anos de 1973/1975, 1984, 1993, 2003, 2007 e 2011 para logo em seguida determinar a localidade mais degradada (ou com menor quantidade de vegetacao nativa). Apos isto, estimou-se a perda universal dos solos para localidade estudada.

Litoestratigrafia e processos geológicos regionais estruturais de formação da bacia do Rio Paracatu (Lithostratigraphy and regional structural geological processes molding Paracatu River...)

Este artigo tem como objetivo apresentar as grandes feicoes litoestratigraficas e tectonicas regionais de formacao da bacia do Rio Paracatu. Pelo vies da abordagem regional, elucidam-se as questoes referentes aos resultados de expressao superficial da bacia pela interacao dos processos exogenos com as estruturas profundas. Sao elaborados mapas de litoestratigrafia, estruturas rupteis, estruturas ducteis, estereogramas e modelos visuais de geologia estrutural. Demonstra-se como a formacao do Domo de Cristalina gerou dobras de descolamento anteparadas pela Serra de Sao Domingos, dando origem as esturutras de sinclinais e anticlinais das Cristas de Unai. A B S T R A C T This paper presents the lithostratigraphy and major regional tectonic processes that molded Paracatu River Basin. Through the regional analysis approach, an investigation is undertaken on how the exogenous processes and the in-depth structures interacted, resulting in the superficial expression of the basin. The results are maps for lithostratigraphy, brittle and ductile structures, stereograms and visual models for structural geology. The paper demonstrates how the Cristalina dome emerged and generated detachment folds, shielded by Sao Domingos Ridge, originating the synclinal and anticlinal structures of Unai Crests. Keywords: Paracatu, lithostratigraphy, structural geology, cristalina dome

Geomorphological maturity profile of the Paracatu river basin.

Francisco River, is presented. The relationship between length and average stream fall for each order using the Strahler method is analysed using empirical laws for a comparison to a theoretical profile of maximum equilibrium. The results show that the Paracatu River Basin is close to its maximum stage of maturity, though it has not achieved it completely. Based on this study, reflections are made about the possibilities to study this watershed based on entropy approaches, metastability, geological vulnerability and geomorphological evolution.