Cleyton de Carvalho Carneiro

Fusão de imagens altimétricas e aeromagnetométricas como ferramenta de interpretação geológica, exemplo da Província Mineral de Carajás (PA)

The Carajas Mineral Province is located in the eastern portion of the Amazonian Craton, in the Para state, north of Brazil. It comprises two main tectonic domains: Carajas and Cinzento strike-slip systems. A significant proportion of the mineral deposits and occurrences of this Province is geologically related to structures belonging to these two fault systems. This paper presents the results obtained by the interpretation of merged altimetric and magnetometric data, as an auxiliary tool for understanding the structural framework of the Carajas Fault. Satellite digital elevation data acquired by the Shuttle Radar Topographic Mission (SRTM) were used in combination with aeromagnetometric data acquired by the Brazil-Canada Geophysical Project (PGBC). A method was developed for digital processing and merging the data acquired by these two surveys, based on geophysical and remote sensing processing methods. The results obtained allowed to establish the relationship between features interpreted from the merged image, with the main geomorphologic and magnetic domains known in the region. These results demonstrate the potential of applying these methods for assessing areas with similar metallogenetic characteristics located elsewhere in Amazon, thus facilitating and guiding regional exploration programs.

Identification of mafic-ultramafic rocks using fuzzy logic classification of airborne geophysical data in the Anapu-Tuerê region, Brazilian Amazon

The Anapu-Tuerê region, in the Brazilian Amazon, is known for the occurrence of mineral deposits associated with mafic-ultramafic rocks. The spatial distribution of these rocks was investigated by integrating airborne magnetic and gamma ray spectrometry data using Geographic Information System (GIS) and fuzzy logic classification. Highest values of relevance fuzzy were associated with mafic-ultramafic rocks mapped regionally by the Brazilian Geological Survey (CPRM). Furthermore, mineral occurrences mapped by the CPRM showed good spatial correlation with the higher values of relevance fuzzy presented in this paper.