RAFT TECTONICS - THE EFFECTS OF RESIDUAL TOPOGRAPHY BELOW A SALT DECOLLEMENT

Some natural examples of thin-skinned extensional structures resulting from gravitational gliding on passive margins, which display complex listric growth fault patterns, are not just controlled by the slope di rection. Examples from the Gulf of Guinea are presented. It is propose d that the inherited topography of the underlying basement can control the initiation of faults oblique to the gliding direction. We carried out a series of small-scale physical models in order to investigate t he effects of residual topography beneath a decollement on faulting in the overlying rafted sedimentary cover. The experimental results sust ain the hypothesis of structural inheritance and their implications ar e discussed in the light of natural examples from the Gulf of Guinea.