Geochronology (Ar/Ar and K–Ar) of the South Atlantic post-break-up magmatism

New geochronological data reveal an asymmetrical magmatic evolution between the African and Brazilian margins during the South Atlantic Ocean opening. While both sides experienced significant post-break-up magmatism, the Brazilian margin shows a higher concentration of pre- and post-break-up volcanic activity, likely due to dynamic shifts in spreading centers and mantle plume activity. The study integrates existing geological data with Ar/Ar and K–Ar dating techniques, highlighting key magmatic events such as the Cabo Granite (104 Ma) in NE Brazil, the SE Brazilian alkaline trend (87–64 Ma), and volcanic islands like Fernando de Noronha (12–1.5 Ma). These findings provide critical insights into the tectonic processes shaping the South Atlantic margins.

Geraldes, M. C., Motoki, A., Costa, A., Mota, C. E., & Mohriak, W. U. (2013). Geochronology (Ar/Ar and K–Ar) of the South Atlantic post-break-up magmatism. Geological Society, London, Special Publications, 369(1), 41–74. https://doi.org/10.1144/sp369.21