Geoelectrical Tomography of the Lithosphere Under the Parana Basin from Gds Data
Abstract
The major geoelectric architecture of the lithosphere beneath the Parana Basin, southeastern South America, is viewed past the highly conducting sedimentary layers, that attenuate to some degree the electromagnetic signal, using very long period geomagnetic array data. It is an area greater than 2 millions square kilometers, in the southern-southeastern region of Brazil and neighboring countries, hindering a clear image of the crust and particularly of the deep upper mantle. 3D models are constructed with long period magnetic data from three-channels fluxgate magnetometers that were deployed for several months during many campaigns carried out in recent years and that covered most of the basin and its borders. The field surveys were set in a grid format with approximately 50 to 100 km intervals between sites, allowing a satisfactory sounding coverage of the region. After critical analysis of the data quality and the processing, the Geomagnetic Depth Sounding (GDS) passive technique is applied to obtain the magnetic transfer functions of the region. The induction vectors show the presence of relevant conductive structures, providing a significant contribution to the understanding of the geoelectrical conductivity distribution of the lithosphere under the Parana Basin and to possible links to tectonic events in this region. Detailed 3D models of some geodynamically relevant areas are used to define key regions for magnetotelluric investigations so that both can be evaluated synergistically with other presently available geophysical data in order to unravel the tectonic evolution of the region.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFMDI23C2094A
- Keywords:
-
- 0910 EXPLORATION GEOPHYSICS / Data processing;
- 0925 EXPLORATION GEOPHYSICS / Magnetic and electrical methods