Shallow necking depth and differential denudation linked to post‐rift continental reactivation: The origin of the Cenozoic basins in southeastern Brazil

• Published in: Terra Nova
• Main Authors: Silva, Rafael M., Sacek, Victor
• Other Authors: Conselho Nacional de Desenvolvimento Científico e Tecnológico, Fundação de Amparo à Pesquisa do Estado de São Paulo, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2019
• Subjects: Geology; South Atlantic Ocean
• Online Access: http://dx.doi.org/10.1111/ter.12423; https://onlinelibrary.wiley.com/doi/pdf/10.1111/ter.12423; https://onlinelibrary.wiley.com/doi/full-xml/10.1111/ter.12423

Abstract The southeastern Brazilian margin presents post‐breakup Cenozoic tectonism that created a series of grabens and small sedimentary basins, known as the Continental Rift of Southeastern Brazil. The formation of this rift occurred long after the South Atlantic ocean opening and has been attributed to different mechanisms like regional uplift induced by hotspot activity, pulses of Andean orogeny and reactivation of pre‐existing faults. However, the proposed models lack an analytical or numerical verification from a geodynamic point of view. Based on finite element modelling of the lithospheric stress field evolution we conclude that a shallow necking depth, consistent with the hyperextended southeastern Brazilian margin, combined with differential denudation of the continent, resulted in an extensional stress field in the upper crust that induced the observed Cenozoic tectonism.