A geochemical and isotopic outline on the Alto Moxotó Terrane: a record of the best-preserved Paleoproterozoic crust in the central Borborema province, NE Brazil

Abstract

The Alto Moxotó Terrane is one of the best-preserved Paleoproterozoic crustal segments of the Borborema Province and shows a close correlation with basement domains of the Central African Fold Belt. Here, we review geochemical and isotopic data for Neoarchean and Paleoproterozoic rocks within the terrane and their implications for the crustal evolution of western Gondwana. The lithospheric framework of the terrane consists of three main tectonomagmatic stages: (1) Neoarchean ( c. 2.6 Ga) crustal accretion with tonalite, trondhjemite and granodiorite juvenile injections, consisting of calcic, magnesian and meta- to peraluminous magmas derived from a basaltic oceanic crust that probably experienced high-pressure conditions; (2) Rhyacian–Orosirian ( c. 2.1–1.9 Ga) tholeiitic mafic–ultramafic and calc-alkaline series Cordilleran-related granitic and gneissic rocks; (3) Statherian–Calymmian within-plate magmatism ( c. 1.6 Ga), with granitic rocks that correspond to A-type ferroan magmas, generated via partial melting of a continental source. The presence of older events within the Alto Moxotó Terrane allows correlation with basement domains within the Borborema Province and other Neoproterozoic orogens of Gondwana. These correlations strengthen the role of the province's Paleoproterozoic domains in palaeogeographical reconstructions of the Nuna–Columbia supercontinents.