Joint inversion of receiver functions and surface wave dispersion in the Recôncavo–Tucano basin of NE Brazil: implications for basin formation

SUMMARY The crustal structure of the Recôncavo–Tucano basin, an aborted rift system that developed in NE Brazil during extension related to opening South Atlantic Ocean, has been investigated through local constraints from receiver functions at 18 seismic stations region. Gravity modelling proved unable unequivocally localize thinning under basin depocentre and, together with a general lack sediments putative thermal sag phase, this led range formation models invoking either pure or simple shear combination both. In particular, ‘flexural cantilever’ model assumed upper crust and lower mantle, enabling erosion flanks after footwall uplift regional phase magmatic underplate basin's crust. Our results reveal is over 40 km thick beneath Tucano Recôncavo basins it contains (5–8 km) layer high velocity (Vs > 4.0 s–1) material below ∼35 depth. These observations contrast immediately West (São Francisco Craton) East (Borborema Province) for which thicknesses average 42 36 km, respectively, velocities are s–1, instances as thin 33.5 observed. We propose, agreement model, fast making lowermost resulted mafic underplating stretching syn-rift restoring thickness pre-rift values (or larger) providing necessary buoyancy trigger uplift. Moreover, although not pervasive, along could be flank erosion. thus conclude that, regardless mode crust, our favour by shear.