The complex geotectonic situation on the eastern part of the Romanche transform and the complex evolution in time of this situation will require much more field work to be unravelled.
The Romanche functioned as a large transform throughout the evolution of the equatorial Atlantic. Although the offset length was probably smaller in the past, this situation makes it very probable that transpressional and transtensional events occurred throughout the history of opening of the equatorial Atlantic, leading to intense vertical motions of lithospherie blocks and intermittent emersion of islands of tectonic origin. The tranverse ridges bounding the equatorial transforms, resulting from such vertical motions, can be traced from one side of the Atlantic to the other. Drilling on one such transverse ridges on the south American margin (north Brazilian Ridge) ended at the base of a sediment pile in Eocene reef limestones BADER1970, suggesting that the transverse ridge was at sea level at that time.
The presence of elevated ridges and islands across the equator has had probably important consequences for deep cold water circulation between the south and the north Atlantic; for sedimentation, both in terms of calcium carbonate dissolution (strongly affected by deep cold water circulation) and transport of terrigenous matter; for faunal migrations, that might have been made possible to some extent by the presence of islands even after the separation of Africa from south America.
