The South Atlantic Ridge (SAR) morphology is investigated, focusing on the topography variation across and along the ridge axis, as well as tectonic segmentation, residual gravity and basalt geochemistry variation. This analysis of the SAR allows inferring on the origin and processes that forms the ridge morphology. The analysis of the SAR morphology on a scale larger than 1.000 km revealed two topographic bulges on the northern and southern ends of the South Atlantic (SA) separated by a relatively deep central region. This morphological variation defined three topographic domains, called North, Central and South, localized around 10ºS, 25ºS and 40ºS. These results suggested an enhanced magmatism under the ridge axis on the north and south of the SAR, while tectonic processes and sparse magmatism controls the central domain. Such a pattern is probably related to processes in the asthenospheric mantle, and suggests regional mantle heterogeneities in the SA. On the northern and southern ends of the SAR, the ridge axis seems to be fed by deep sources in the mantle, as indicated by the large bulges observed, while the central part of SAR is probably related to a denser and/or cooler region. More detailed analysis of the SAR morphology revealed the existence of 20 tectonic segments, which showed a remarkable variation. The central rift valley with an average depth of 3,267 m is usually observed along the SAR, but certain regions lack central rift. The width of the central valley as well as the height of the rift mountains vary quite a lot, suggesting the importance of local accreting processes influencing the ridge axial morphology.
Ridge morphology; Ridge structure; South Atlantic Ridge
