The 2.58 Ga São José do Jacuipe gabbro-anorthosite stratiform complex, Itabuna-Salvador-Curaçá Orogen, São Francisco Craton, Brazil: Root of the Neoarchaean Caraiba continental arc?

•The São José do Jacuípe Gabbro-Anorthosite Complex is composed mainly of anorthosites, leucogabbros, and gabbros.•Field relationships, pyroxene chemistry, negative Nb anomaliess, and positive εNd(t) values similar to arc rocks.•The complex can be the root of the Neoarchaean Caraíba magmatic arc.

Mafic-ultramafic complexes are common in ancient orogenic belts and can represent arc roots, obducted ophiolite remnants, continental intrusions, subducted oceanic plateaux or lithospheric mantle fragments. The Archaean-Palaeoproterozoic Itabuna-Salvador-Curaçá̧ Orogen hosts several mafic-ultramafic complexes, whose petrogenetic understanding is difficult owing to the high-grade metamorphism and deformation. One of these complexes is the 2583.7 ± 7.7 Ma São José do Jacuípe Gabbro-Anorthosite Complex, composed of massive to stratiform, deformed and metamorphosed anorthosites, leucogabbros, and gabbros with minor pyroxenites. Field relationships of the mafic-ultramafic rocks combined with calcic-pyroxene chemistry, negative Nb anomalies in mantle-normalised diagrams, and dominantly positive εNd(t) values suggest similarities with arc mafic magmatism. The gabbro-anorthosite complex matches the ages of arc orthogneisses (2574 ± 6 Ma) and norite-hypersthenite complex (2580 ± 10 Ma) of the Caraiba Complex and is thus interpreted as a fragment of the root of the Neoarchaean Caraíba magmatic arc within the Itabuna-Salvador-Curaçá Orogen.