Paleoproterozoic Continental Intraplate Mafic Magmatism and its Contemporaneous Global Links: Evidence from the Southern Part of The Bastar Craton, Central India

The current study presents a detailed investigation of the field relationships, whole-rock geochemistry, Nd isotope analysis and zircon geochronology of less-studied mafic volcanic–subvolcanic extrusive rocks from the Bengpal Group, southern Bastar Craton. This study reports the first U-Pb zircon date (~2.25 Ga) for a coarse-grained mafic rock, providing a precise crystallization age for these mafic rocks of the Bengpal Group. These extrusive mafic rocks exhibit tholeiitic characteristics and are geochemically classified as basalt to basaltic andesite. Moreover, these rocks exhibit primitive mantle normalized enrichment in LILEs and relative depletion in HFSEs (Nb, Ta, P, and Ti). Four cumulate samples show high-Ti nature (TiO₂ = 2.09–2.75 wt%) and are geochemically distinguished by the enrichment of Fe-Ti, Nb, Ta, and REEs, hence classified as high-Ti basaltic rocks.

The initial εNd values and other immobile trace element concentrations of the Bengpal mafic rocks suggest that these rocks are derived from lithospheric mantle (at shallow depth) with a depleted mantle source, accompanied by minor input of crustal assimilation and crystal fractionation. Based on the association of volcano-sedimentary rocks and geochemical signatures, we propose that these preserved volcanic–subvolcanic mafic rocks were emplaced in a stable continental shelf-like environment within an intraplate setting.

The Bengpal mafic rocks are correlated with previously reported coeval continental intraplate mafic magmatic events in other cratons in the Indian subcontinent and worldwide. This global correlation indicates a potential connection with global mafic magmatic events associated with intracontinental rifting events. Therefore, the new precise U-Pb dating of zircon unravels that this magmatic event is most likely associated with early Paleoproterozoic supercontinent break-up events driven by global-scale intracontinental volcanic activities.