Basement geology and its controls on the nucleation and growth of rift faults in the northern Campos Basin, offshore Brazil

The rift phase of the Campos Basin developed during Early Cretaceous on a heterogeneous crust comprising structures inherited from Brasiliano-Pan African tectonic events, mostly generated Neoproterozoic-Cambrian amalgamation western Gondwana blocks. main rifting episode took place Hauterivian to Barremian, then was succeeded by transition and post-rift (SAG) phases Aptian. Rift faults as result progressive rotation extension E-W NW-SE. role pre-existing intra-basement style evolution investigated using 3D high-resolution seismic data, borehole logs sidewall samples. Three facies (SF1, SF2 SF3) three types (Surfaces, Geobodies Internal Reflections) were identified mapped. They represent, respectively, contrasting levels anisotropy, interpreted metamorphic foliation, ductile shear zones that bound rock units with particular signatures. Sidewall cores show banded biotite-gneiss is predominant type in eastern half study area, while more homogeneous granitoid dominant lithology west. Such binary division lithotypes consistent distribution mapped features. basement heterogeneity across area major control strain rifting. Where highly heterogeneous, fabric selectively reactivated whenever its orientation favourable, resulting forming progressively direction rotates, whilst shallower low very angle cross-cut faults. homogeneous, only early formed remain active throughout