The deep structure of continental rift zones and passive margins is regularly addressed to discuss primary aspects of rift development, including the location and geometry of fundamental, crustal-scale structures and the degree of re-activation of inherited structural grains. These primary parameters affect directly the magnitudes of stretching and subsidence, the routing of sediments from source to sink and the location of depocentres in the syn-and post-rift stratigraphy. Both scientifically and commercially, the understanding of these processes and parameters is important. In deep rift basins, however, interpretation of structural style, modes of extension and their impact on subsidence patterns and basin geometry may be hampered by poor seismic coverage for levels deeper than the 6-7 s two way time (twt) commonly covered by commercial seis mic surveys.