Produção Nacional
Assinatura geofísica e modelos prospectivos ‘knowledge-driven’ de mineralizações de Au no lineamento Congonhas, sul do Cráton São Francisco, MG
2007; Sociedade Brasileira de Geologia; Volume: 37; Issue: 3 Linguagem: Inglês
10.5327/rbg.v37i3.1290
ISSN2317-4889
AutoresCarolina Miethke, Carlos Roberto de Souza Filho, Adalene Moreira Silva,
Tópico(s)Remote-Sensing Image Classification
ResumoThis research focused on identifying and describing geologic-geophysical signatures of gold occurrences associated with a regional scale shear zone (Congonhas Shear Zone), south of the Iron Quadrangle in the State of Minas Gerais, Brazil. The work aimed at combining and analyzing digital spatial data and developing predictive models for lode-type gold mineralization. Aerogeophysical and multispectral orbital data, in addition to geological and gold occurrence maps, were employed both separately and in an integrated approach. The digital processing steps involved several enhancement techniques – conventional (pseudocolor compositions, unsupervised classification and principal component analysis), knowledge-driven (boolean and fuzzy logic), as well as techniques originally developed for the classification of hyperspectral remote sensing data (Spectral Angle Mapper and Mixture Tuned Matched Filtering), which were here adapted to aerogeophysical data processing. The results yielded by the processing, integration and interpretation steps proved the spatial analysis and classification methods to be effective in the selection of targets potentially mineralized in gold. Sites with known occurrences of this metal, associated to lithological units affected by hydrothermal alteration related to the Congonhas shear zone, were successfully mapped. Additionally, other key areas, where no gold occurrences are known, were also individualized and will require further field verification to be validated.
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