Kinematic keys of the Santos-Namibe basins
Résumé
Understanding the genesis of the very peculiar 600 km-wide Santos Basin-São Paulo Plateau system and its narrow conjugate Namibe Margin is a kinematic and structural problem. Several hypotheses have been proposed in order to explain the genesis of this system that imply the same amount of horizontal movement. We investigate the consequences of the horizontal movement in the Santos Basin, based in plate kinematic reconstructions. The kinematic history of this system that we present here, based on the interpretation of seismic profiles and kinematic constraints, has the following consequences: (1) there is no evidence of a ridge jump sensu stricto but, rather, a southwards propagation in the Central Segment of the South Atlantic that starts in the northern part, between the NE Brazilian and Gabonese margins; (2) the Namibe margin evolved as a transform passive margin; (3) the opening direction of the Santos Basin-São Paulo Plateau system is oblique to the general opening motions of the South American and African plates; and (4) this opening is younger (6 Ma) than those of the other basins of the Central Segment of the South Atlantic.