Geochemistry and Age Constraints of post Iron Ore Supergroup Mafic-ultramafic Magmatism in Darjing Group and Bonai Granitoid Complex, North Odisha Singhbhum Craton, India

ABSTRACT Mesoarchean mafic-ultramafic magmatic activities show a regular pattern in different cratons across the world and it starts with peridotitic members to pyroxenite to Geochemical Analog of Boninite (GAB) to Siliceous High Magnesium Series (SHMS) type. Magmatic activities with similar geochemical characteristic and same evolutionary trend i.e., from ultramafic to GAB to SHMS are observed in enclaves of BGC and sill of Darjing Group. Based on coherent geochemical character and intrusive field relation of these two mafic-ultramafic suites of rocks, it can be concluded that they are cogenetic and emplaced late to post first deformation of Iron Ore Supergroup orogeny with an Archean geochemical analog of modern island arc setting. Erstwhile these were classified as two different stratigraphic units. Geochemical data also indicates an enriched mantle source for this event. Besides, geochronological constraints specify its intrusion time (~2.9 Ga to ~3.0 Ga) that can be appraised with other similar events from Singhbhum Craton as well as from other cratons of different part of the world.