The Southern Brazilian Margin: an Example of a South Atlantic Volcanic Margin
K. Gonçalves De Souza, R.L. Fontana, J. Mascle, J.M. Macedo, W.U. Mohriak and K. Hinz
Event name: 3rd International Congress of the Brazilian Geophysical Society
Session: Simposium: Marine Geophysics in Atlantic-Type Oceans
Publication date: 07 November 1993
Info: Extended abstract, PDF ( 2.72Mb )
The seismic reflection and drilling data show that the Southern Brazilian margin (Pelotas and Santos basins. Florianopolis High and Sao Paulo Plateau) is of a volcanic type. characterized by the effusion of flood basalt sequences (seaward dipping reflectors). recognized along a 70 to 380 km wide band parallel to the coast line. The flood basalt sequences. which may be as thick as 8 krn, was emplaced between the Early Valanginian and the Late Aptian. The volcanic rocks are partially overlain by clastic sediments. Both, volcanic rocks and clastic sediments are related to the synrift phase that preceded the openning of the Southern South Atlantic. The presence of the volcanic sequences along the Southern Brazilian margin. and of similar age and of similar seismic characteristics on the Argentinean margin and on the conjugate margins of South Africa and Namibia (where the seaward dipping reflectors have also been identified) indicates that the southern portion of the South Atlantic is borded by volcanic type margin.