Crustal Evolution of the Pernambuco-Alagoas Complex, Borborema Province, NE Brazil: Nd Isotopic Data from Neoproterozoic Granitoids

摘要: The Borborema Province in northeast Brazil forms the western part of a major 600 Ma Brasiliano-Pan-African mobile belt that extends from through Central Africa pre-drift reconstruction Gondwanaland. Pernambuco-Alagoas (PEAL) complex is large area within Province, and consists high-grade migmatitic gneisses granitic batholiths. Although PEAL has previously been called "massif" or "terrane", reality it comprises many different types protoliths plutons. for are difficult to decipher due varied deformation metamorphism during Cariris Velhos Brasiliano orogenies. Nd isotopic data discriminate two crustal domains complex: Garanhuns Agua Branca domains. Rocks domain have TDM range 1.8 2.4 Ga, indicating most underlain by Paleoproterozoic crust, does not include significant Mesoproterozoic Neoproterozoic additions. Marimbondo-Correntes batholith inside domain, but includes younger ages similar those found domain. This contributions sources may intrude block allocthonous crust thrust over older show 0.90 2.10 with model between 1.5 1.0 Ga. pre-Brasiliano this thus substantial amounts presence some suggests Aguas Belas vertical zonation, segments tectonically interleaved successive accretional collisional episodes, including ultimate collision at Ma. ages, therefore represent mixing mantle sources, rather than discrete episode formation. Various metaluminous peraluminous granitoids age Buique-Paulo Afonso, Belas-Caninde, batholiths ranging Ga 1.10 suggesting they either were wholly derived juvenile material orogeny contain 0.6 cycle. Some high-K shoshonitic (∼1.4 Ga) ages. recorded these plutons could suggest magma was enriched lithospheric associated mixture lower Transamazonian