Seismic Mantle Structure Underneath SE Brazil


The P- and S-wave velocity perturbation model published in Schimmel et al. (2003) can be downloaded here.

Foto by Flavio Cannalonga

Marcelo Assumpção to the right and Martin Schimmel to the left
(from Pesquisa, 53, 20-27, 2000, foto by F. Cannalonga)

This study at scales of cratons and fold belts is motivated by the presence of the major structural units of Western Gondwana, younger mobile fold belts and relics of the opening of the South Atlantic ocean such as continental flood basalts (CFB) and dyke swarms. The upper mantle structure is expected to correlate to these surface tectonic environments and can reveal hidden anomalies and limits of structural units which are controversial due to the presence of cover rocks.

A prime tool to illuminate mantle structure is seismic tomography. Although it lacks the resolving power to constrain mantle discontinuities it provides us with reconstructions of the long and intermediate scale structure. We use this tool to map the P- and S-wave velocity anomalies underneath SE-Brazil.

In the following we list some selected figures which you can view by clicking on the highlighted text. The results are compiled in a publication (download pdf.gz [6.7Mb] ). In our publication you can find the details and more figures about the tectonic settings, the resolution and data consistency tests. Informations on the seismic anisotropy, the upper mantle deformation in SE Brazil, and a franco-brazilian portable seismic experiment are also provided by the tectono-physics group in Montpellier.

The dashed lines mark our study area (e.g. see the station map for more details, figure from Pesquisa, 53, 20-27, 2000).

P-wave velocity perturbations along the cross section A-A' (from Pesquisa, 53, 20-27, 2000).

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