| Journal: | Revista brasileira de geofisica |
| Database: | PERIÓDICA |
| System number: | 000279575 |
| ISSN: | 0102-261X |
| Authors: | Arora, B.R1 Trivedi, N.B Vitorello, I Padilha, A.L Rigoti, A2 Chamalaun, F. H3 |
| Institutions: | 1Instituto Nacional de Pesquisas Espaciais, Sao Jose dos Campos, Sao Paulo. Brasil 2Universidade Federal do Parana, Departamento de Geologia, Curitiba, Parana. Brasil 3Flinders University of South Australia, School of Earth Sciences, Adelaide, Australia Meridional. Australia |
| Year: | 1999 |
| Season: | Mar |
| Volumen: | 17 |
| Number: | 1 |
| Pages: | 43-65 |
| Country: | Brasil |
| Language: | Inglés |
| Document type: | Artículo |
| Approach: | Experimental, analítico |
| English abstract | Geomagnetic Deep Sounding (GDS) is an electromagnetic method of geophysics, which is capable of imaging the Earth146s interior in terms of electrical conductivity using natural geomagnetic transient variations. The method is particularly suited to map geological structures marked by large lateral conductivity contrasts. An overview of the methodology is presented for a magnetometer array study undertaken within and around the intracratonic Parnaíba Basin, north-northeast Brazil. The article describes the sequential steps of data processing, the results of numerical modeling, and the related geological/tectonic implications of the inferred conductivity distribution. In the initial stages of data processing, an advanced robust regression technique is applied to derive transfer functions used to diagnose the lateral conductivity distribution in the study region. The presentation of the transfer functions in the form of induction arrows helps to identify regions of enhanced conductivity. Contour plots and pseudo-sections of the anomalous vertical fields, estimated from the hypothetical event analysis on transfer functions, are essential to characterize the orientation and dimensionality of the electrical conductive structures of the region. The analysis of various frequency and polarization parameters indicates that an anomalous behavior of the magnetovariational field, with periods longer than one hour, is determined by currents induced in the seawater, and perhaps in the raised asthenosphere beneath the oceanic region |
| Disciplines: | Geociencias |
| Keyword: | Geofísica, Inducción electromagnética, Sondeos, Conductividad eléctrica, Cuencas, Magmatismo |
| Keyword: | Earth sciences, Geophysics, Electromagnetic induction, Soundings, Electric conductivity, Basins, Magmatism |
| Full text: | Texto completo (Ver HTML) |
