A Juvenile Component in the Pre- and Post-Collisional Magmatism in the Transition Zone between the Araçuaí and Ribeira Orogens (SE Brazil)

The Araçuaí and Ribeira orogens have been studied for decades, recently, these two were described as the Araçuaí–Ribeira Orogen System. Despite much work investigating this orogenic system, some issues, such connection between orogens, are still not fully understood. This aimed to present unpublished Lu-Hf data Santa Angélica Intrusive Complex (SAIC) host rocks that part of Rio Negro magmatic arc, well U-Pb ages rocks, thus contributing understanding geological processes acted in transition zone orogens. Two samples collected corresponding arc six from Complex. zircon grains separated subjected geochronological (U-Pb) isotopic (Lu-Hf) analysis by laser ablation-induced coupled plasma mass spectrometry (LA-ICP-MS). indicate a crystallization age ca. 595 Ma. In contrast, Hf point at least sources, one crust, mantle. obtained SAIC show three peaks. first peak (537 ± 5 Ma) coincides with process crustal anatexis possibly marks beginning generation magmas associated post-collisional magmatism. second (510 registers apex SAIC, third (488 7 upper limit magmatism SAIC. components mantle component (juvenile).