Geometry of Five Submarine Slumps Complexes - Campos Basin, Brazil

In the Campos Basin, offshore Rio de Janeiro State, Brazil, between Săo Tome Canyon, to the north, and Grupo Sudeste de Cânions, to the south, the late Miocene to recent sediments of the continental slope comprise submarine slumps complexes. Seismic mapping of these slumps has provided some clues to its geometry and behaviour. The slumping processes were recurrent in the geologic time generating a series of six slumps here named Slump I (the oldest) to Slump VI (the youngest). The maximum thickness of these slumps ranges from 50 to 85 m and cover areas ranging from 875 to 1575 km>, The slump III was not completely traced due to its less regional significance. The submarine slumps IV, V and VI show a complete slump structure consisting of head, body and toe regions, while in the slumps I and II only body and toe regions are present. It was observed that extensional structures (normal faults) prevail at the head and the compressional ones (thrust faults and folds) in the toe region. Triggering mechanisms for slumping are not completely understood, Costa et al. (1994) and Viana et al. (1994), consider the lowering of the sea level the principal slumping factor.