The Serra do Caparaó Complex, Mantiqueira Province, Brazil, revisited: metamorphic age constraints by U-Pb and Lu-Hf method in zircon by LA-ICP-MS

Abstract

ACCEPTED MANUSCRIPT - UNCORRECTED PROOF The U-Pb method has been used in order to understand the high-grade metamorphic rocks in the Ribeira Belt (SE Brazil) and Lu-Hf isotopes were applied to investigate the sources of the magmatic photolith and the tectonic setting of the Serra do Caparaó Complex rocks. The results indicate the existence of two thermal events: the first related to a Paleoproterozoic magmatic event and the second one linked to high-grade metamorphism related to the Brasiliano Orogeny. The U-Pb age interval from 2209 to 2060 Ma obtained in zircon grains from the granulitic orthogneiss with TDMcrustal ages ranging from 2.13 to 3.87 Ga may be interpreted as mantle-derived source with important older crust participation in the magma formation; juvenile arc-related rocks were generated at this time as indicated by the positive ƐHf values. The second group of U-Pb ages ranging from 633 to 584 Ma is interpreted as a metamorphic event, resulting from the collisional process related to the Gondwana assembly.

Keywords

• LA-ICP-MS
• zircon in situ analysis
• U-Pb
• Lu-Hf
• Ribeira Belt
• Gondwana assembly