Mesozoic rifting structures between Campos and Santos basins, Cabo Frio, Brazil: magnetic and structural analysis

The crustal structure and extension during the Mesozoic South Atlantic rifting in the CaboFrio region, between the Campos and Santos basins, is investigated based on onshore brittle structuresand offshore aeromagnetic anomalies. A correlation between the fault systems, the kinematic indicatorsof tholeiitic dykes of the Cabo Frio Dyke Swarm and the pattern of magnetic anomalies show evidenceof widespread extensional tectonics, with an increasing rate towards offshore and an obliquecomponent in the first stages of rifting. The pattern of magnetic anomalies also suggests an offshoreprolongation of the Cabo Frio basement and a possible transitional crust zone.