An overview on the Rhyacian–Orosirian (ca. 2.1–2.0 Ga) granitic magmatism of the Alto Moxotó Terrane and its implications for the crustal evolution of the Borborema Province, NE Brazil

Several ca. 2.1–2.0 Ga deformed granitic-gneissic suites form most of the crustal framework of the Alto Moxotó Terrane of the Borborema Province (NE Brazil). In this study, we present the available geochemical and isotopic data of such rocks and their implications for the crustal evolution of this portion of Western Gondwana. The studied rocks present a wide compositional spectrum ranging from tonalites to alcali-feldspar granites both in petrographic and chemical investigations. They vary from calc-alkaline to shoshonitic, sharing similarities with magnesian meta- to slightly peraluminous magmas. Minor element distribution, rare-earth element patterns and tectonic discrimination diagram plots suggest derivation via upper mantle melting during a subduction-related setting. In addition, calculated positive to negative epsilon neodymium values and Archean to early Paleoproterozoic T DM model ages are suggestive of juvenile inputs followed by crust reworking in a relatively stable Archean accretionary margin. The recognition of a Paleoproterozoic orogenic event in the region present major implications for correlative efforts between basement terranes in the Borborema Province and other Paleoproterozoic blocks along Western Gondwana, such as those from the São Francisco-Congo Craton and several other basement inliers along the Neoproterozoic orogenic belts of West Africa.