Mesoarchaean to Palaeoproterozoic growth of the northern segment of the Itabuna–Salvador–Curaçá orogen, São Francisco craton, Brazil

Abstract

AbstractThe geology of the northern segment of the Itabuna–Salvador–Curaçá orogen, São Francisco craton, is reviewed, and new U–Pb ages, and Nd isotope and major and trace element data are combined to improve understanding of its tectonic evolution. The results indicate that oceanic crust and island arc sequences accreted at about 3.30 Ga to form the Mundo Novo greenstone belt, and between 2.15 and 2.12 Ga to form the Rio Itapicuru and Rio Capim greenstone belts. At about 3.08–2.98 Ga, mafic crust underwent partial melting to form the Retirolândia and Jacurici tonalite–trondhjemite–granodiorite belts of the Serrinha block. From 2.69 to 2.58 Ga an Andean-type arc with ocean crust remnants formed the Caraiba complex possibly at the Gavião block margin. Between 2.11 and 2.105 Ga, the Rio Itapicuru arc collided with the Retirolândia–Jacurici microcontinent, possibly involving slab breakoff. Oblique convergence between 2.09 and 2.07 Ga led to collision of the Serrinha microcontinent with the Caraíba–Gavião superblock and reworked the Caraíba arc to granulites, locally at ultrahigh-temperature conditions. At the same time, arc dacites spread over the Rio Itapicuru greenstone belt, and the 3.12–3.0 Ga Uauá terrane, crosscut by 2.58 Ga mafic dykes, extruded from south to north, possibly together with the 2.15 Ga Rio Capim greenstone belt.