While proximal domains in rifted margins are commonly associated with moderate crustal thinning, those developed along ancient orogenic belts, for example,can show more complex architectures influenced by pre-existing heterogeneities. Here, the interplay between inherited and rift-related structures is crucial, contributing to the complexity of these proximal marginal domains. This study investigates the role of pre-existing Gondwana structures in the development of a proximal breakaway complex, and the formation of a V-shaped basin within the Cretaceous Campos Basin. We use seismic reflection data and potential-field maps to characterize the structural framework of the study area. By combining observations regarding basement morphology, fault systems, and intracrustal reflectors, with gravity and magnetic sources, the study proposes a three-segment structural model (north, central, south) for the central Campos proximal domain. Wediscuss the reactivation of pre-existing basement fabric that led to the exhumation ofa middle ductile crust coeval to a localized shift of depocenters in the Barremian. These processes influenced the spatial distribution of faults and the development of a secondary WNW-ESE transfer zone, as well as the opening of a V-shaped basin associated with adome-shaped Central High. This study delineates a boundary for the Campos proximal domain and discusses, for the first time in the Campos Basin, the opening of a V-shaped basin as a result of differing vertical mechanical behavior combined with a sequence of tectonic reactivations of pre-existing basement structures. This contribution aims at enhancing our understanding of structural responses of a heterogeneous crust during the initial stages of rifting. • We characterized a proximal breakaway complex at the central Campos rifted margin. • Pre-existing basement fabric reactivation drove middle crust exhumation. • Rift structures include a minor E-W transfer zone and detachment faults. • Tectonic reactivations led to shifting depocenters and opening of a V-shaped basin.
Hunger et al. (Fri,) studied this question.