The Influence of Oceanic Fracture Zones on the Segmentation and Structural Control of Continental Margins

This contribution has three primary objectives: 1) We demonstrate that there are notable regions in both the Central and South Atlantic that are devoid of secondary fracture zones, following structural interpretation of high quality aeromagnetic and satellite-derived gravity data; 2) A self-consistent plate model is implemented to perform quantitative analyses of the opening directions (and therefore fracture zone orientations) of the Central and South Atlantic. These are used to correlate the appearance of secondary fracture zones with changes in spreading direction and major plate re-organisational events; 3) We provide a plate tectonic mechanism to account for the discontinuous nature of fracture zones in the Central and South Atlantic, and conclude that small offset transform faulting did not influence the evolution of the continental margin in the offshore Angolan and Brazilian regions, as has been previously suggested.