Regional High-Grade Metamorphic Peak Imprint in Zircons from the Mafic-Ultramafic Jacurici Complex, São Francisco Craton, Brazil

The Cr-rich Jacurici Complex is located at the limit between the Serrinha Block and the Salvador-Curaca Belt, Northeastern Sao Francisco Craton. In order to better understand the age span of magmatism and tectonism, we have studied a basement high-grade charnockite orthogneiss, a metanorite of the Complex and a crosscuting undeformed quartz-feldspar pegmatite. For the orthogneiss, SHRIMP U-Pb ages of zircon cores and overgrowth rims yielded, 2966 +/- 9 Ma for crystallization and 2091 +/- 10 Ma for metamorphism, respectively. Zircons from the metanorite show internal textures consistent with high grade metamorphism. The U-Pb LA-ICP-MS age determination provided a 2099 +/- 6 Ma metamorphic age for the Jacurici Complex, indicating it was already emplaced during amalgamation around 2.1 Ga. Zircons from the undeformed quartz-feldspar pegmatite provided a LA-ICP-MS U-Pb age of 2083 +/- 11Ma, marking the end of the N-S transcurrence. The magmatic Jacurici Complex age remains undefined, but is equal to, or older than, 2.1 Ga. Therefore, possible correlations with other mafic-ultramafic intrusions, such as the Cu-rich Caraiba Complex, should be reassessed. Our results indicate that the N-S transcurrence ended earlier in the Jacurici Complex region than in the northwestern area of the Salvador-Curaca belt.