Desenvolvimento de Técnicas de Filtragens e sua Aplicação a Dados Aeromagnéticos da Bacia Amazônica

Abstract

ln this work two filtering methods were combined in order to enhance somente features in aeromagnetic maps such as lineaments and anomalies caused by sources of large proportions. The visual filtering consisted of stereoscopic examination of maps. The numerical filtering involved elimination of undesirable spectral components (noise) and enhancement of desirable spectral components (signal). Both methods were tested on aeromagnetic maps of the Middle Amazon Basin. A further topic also discussed is basement fault models. A structural interpretation of the Middle Amazon Basin basement is provided. The dominant aeromagnetic trends are E-WN 60oW, N-S, N450E and N60oE. Two grabens are quite evident. The younger one trends N-S, while the older onde strikes N45oE. Two anomalies caused by sources of intermediate and great proportions (15-60 km) exhibited remanent magnetization and high values of negative inclination, which shows that during Paleozoic the Amazon Basin occupied a position much more to the South. ln performing the integration of aeromagnetic data with other geophysical data available, the interpretation from other data proved consistent with the aeromagnetic interpretation, illustrating the reliability of the techniques employed in this work.