Paleoarchean to Paleoproterozoic crustal evolution in the Guanambi-Correntina block (GCB), north São Francisco Craton, Brazil, unraveled by U-Pb Geochronology, Nd-Sr isotopes and geochemical constraints

Abstract

The north-central part of the São Francisco Craton (SFC) is one of the oldest terranes in the South American platform and experienced three regional magmatic events at 3.4–3.3, 3.1–2.7, and 2.1 Ga. Our new SHRIMP U-Pb data place the origin of Guanambi-Correntina block (GCB) in the Paleoarchean, contemporaneous with the Gavião block in central north SFC. Lithological, geochemical, and isotopic evidence indicate that the 3.4–3.3 Ga rocks of the Favelândia complex are derived from partial melting of E-MORB sources during flat subduction. The 3.1–2.7 Ga K-granitoids in the Santa Izabel complex are derived from a mixture of crustal and mafic sources, as evidenced by the slightly negative to positive ƐNd(T) and Sr/Sri between 0.700 and 0.706. The 3.1–2.7 Ga event is responsible for the recycling of the Paleoarchean TTG crust, generation of low- to high-K evolved crust, and juxtaposition of the Favelândia and Santa Izabel complexes. The youngest magmatic event at ca. 2.1 Ga produced felsic plutons, derived from anatexis of Archean felsic rocks and mantle components. The collisional process tectonically juxtaposed the Riacho de Santana greenstone belt and Archean felsic rocks at 2.1–2.0 Ga, determining the region’s current configuration. Based on the data reported in this study and previously published data, we suggest that the Guanambi-Correntina block was formed as an independent unit in the northern SFC.