Neoarchean (ca. 2746–2501 Ma) magmatism: Evidence from east coast dykes of northeastern Southern Granulite Terrain, India

We report new Sm–Nd whole rock-mineral isochron ages of 2514 ± 13 Ma (MSWD = 0.79) and 2651 ± 95 Ma (MSWD = 7.4) from two east coast dykes (ECD) of Southern Granulite Terrain (SGT), India. The ages from the representative mafic dyke samples correspond to the time of intrusion of ECD into the eastern part of SGT, indicating the presence of an older Archean crust in SGT near the Pondicherry coast. The Sm–Nd ages obtained from the present study, along with geochronological information from Singhbhum Craton, suggest a magmatic linkage between SGT (including southern Dharwar Craton) and Singhbhum Craton during the Neoarchean period. The older ages obtained from the mafic dykes of the present study are comparable with the Sm–Nd ages of older mafic dykes from Nuggihalli green stone belt of Western Dharwar Craton (WDC), Pb–Pb ages of mafic dykes from Singhbhum Craton of India and the U–Pb ages from Pilbara and Kaapvaal cartons. These comparisons unlock a clue to Neoarchean (2.8–2.5 Ga) paleogeographic reconstructions of Pilbara, Kaapvaal, Singhbhum cratons, northern SGT (including southern Dharwar Craton) and also provide an opportunity for wide windows of research to be undertaken considering the dykes from SGT. Research highlights Evidence of Neoarchean magmatism from East coast dykes near Pondicherry coast of Southern Granulite Terrain, India. Sm–Nd ages of 2514 ± 13 and 2651 ± 95 Ma represent the time of intrusion of east coast dykes in Southern Granulite Terrain. Isotope age indicates the presence of ~2.7 Ga older Archean crust near Pondicherry coast of Southern Granulite Terrain. Geochronological studies reveal a magmatic linkage between Southern Granulite Terrain and Singhbhum craton. The present study provides clues to the connection between Pilbara, Kaapvaal with SGT and Singhbhum cratons.