2D lithospheric multiphysics modeling of the Vitória-Trindade Ridge – South Atlantic Ocean, Brazil

The Vitória-Trindade Ridge and the Abrolhos Magmatic Province are located in southeastern Brazil, between the coast of Brazil and the mid-ocean ridge of the Atlantic Ocean. The origin of Vitória-Trindade Ridge is debated; therefore, we conducted the lithospheric structure and mantle heterogeneity model along two east-west transects that cross the Abrolhos Magmatic Province in the Brazilian Continental Margin and the Vitória-Trindade Ridge in the Atlantic Ocean, using an integration of geophysical, petrophysical, and geochemical data constrained by thermophysical parameters. The model results show that the continental region has a thicker crust than the continent-ocean transition zone, and the oceanic region beneath the Vitória-Trindade Ridge has the thinnest crust. Further, the Lithosphere-Asthenosphere Boundary depth is thicker in continental areas, while it is shallower in the continent-ocean transition zone. Beneath the Vitória-Trindade Ridge, lithospheric thinning leads to a significantly reduced Lithosphere-Asthenosphere Boundary depth. This study also presents a geophysical model in which the hybrid mantle beneath the Vitória-Trindade Ridge, in terms of geochemical composition and seismic velocity, is attributed to a mixture of depleted mid-ocean ridge basalts mantle and pyroxenite. Our results suggest that the mixture comprises 85 % depleted mid-ocean ridge basalts mantle and 15 % pyroxenite.