Palaeoproterozoic ancestry of Pan-African high-grade granitoids in southernmost India: Implications for Gondwana reconstructions

Abstract SHRIMP dating of magmatic zircons from granitoid gneisses and charnockites of the Trivandrum and Nagercoil Blocks in the granulite terrane of southernmost India yielded well-defined protolith emplacement ages between 1765 and ca. 2100 Ma and also document variable recrystallization and/or lead-loss during the late Neoproterozoic Pan-African event at around 540 Ma. Hf-in-zircon and whole rock Nd isotopic data suggest that the granitoid host rocks were derived from mixed crustal sources, and Hf–Nd model ages vary between 2.2 and 2.8 Ga. A gabbroic dyke, emplaced into a charnockite protolith and deformed together with it, only contained metamorphic zircon whose mean age of 542.3 ± 4.0…