Multiple rifting and alkaline magmatism in southern India during Paleoproterozoic and Neoproterozoic

摘要: Abstract The Southern Granulite Terrane (SGT) in India preserves the history of tectonothermal events ranging from Paleoarchean to latest Neoproterozoic–Cambrian. Here we investigate alkaline magmatism possibly associated with rifting Paleoproterozoic and Neoproterozoic based on petrological, geochemical zircon U–Pb Lu–Hf isotopic studies complexes Korangani (KGAC) Kambamettu (KAC) Madurai Block SGT. mica pyroxenite which represents first intrusive phase at KGAC crystallized a mildly hydrous magma derived metasomatized mantle. younger shoshonitic syenite was emplaced 2533 ± 16 Ma, carries mafic microgranular enclaves, shows trace-elements ratios consistent mixing trend, eHf(t) values display mixed positive negative − 2.6 3.6 suggesting adakite-like felsic crustal melt non-adakitic mantle melt. In KAC, four distinct magmatic intrusions are identified: i) quartz-monzonite (emplaced 2498 ± 16 Ma), an ultrapotassic adakitic rock carbonated alkali-rich lower source zircons (− 8.0 − 0.8); Y/Nb (> 1.2) Th/Ce (0.03–0.8) ratios; Ni ( features petrogenetic considerations shoshonitic-ultrapotassic rocks (syenite, quartz monzonite), mica-pyroxenites carbonatite reveal rift-related extensional tectonic settings sources involving both components during Paleoproterozoic. late KAC also formed setting. cases, intracontinental post-collisional extension is proposed.