SHRIMP U–Pb zircon geochronology and Nd signatures of supracrustal sequences and orthogneisses constrain the Neoproterozoic evolution of the Pernambuco–Alagoas domain, southern part of Borborema Province, NE Brazil

摘要: The Borborema Province is the western part of a major Brasiliano belt that extends from Brazil through NW Africa in pre-drift reconstructions. This province resulted convergence and collision among West African, Congo-Sao Francisco, Amazonian cratons about 600 Ma. study focuses on Pernambuco–Alagoas (PEAL) domain, which complex magmatic, migmatitic, metamorphic rocks, located southern Province. U–Pb geochronology Sm–Nd data for metasedimentary sequences (Rio Una, Inhapi) PEAL domain sample sequence Transversal Zone suggest their deposition occurred during Cryogenian extensional event, within interval 850–631 Ma (or slightly younger). event PEAL, Zone, Sergipano domains before onset was followed by syn- post-collisional magmatism. Rio Una were deposited over Rhyacian (ca. 2.0–2.2) basement having juvenile Palaeoproterozoic Nd signature, whereas Inhapi an Early Neoproterozoic (Tonian) basement. studied coeval with to north south other However, differences isotopic signatures between they formed distinct basins. Metasedimentary have Meso- T DM model ages. These orogens where are strong ensialic component. ages ca. 1.0 Ga eNd (0.6 Ga) values around zero recorded granites suggesting material accreted crust Tonian. migmatites wide range along values. transition northern parts denotes approximate margin Late Mesoproterozoic rift.