The Deccan Chronicle: perspective of the Deccan dikes

The Deccan Volcanic Province (DVP), one of the most discussed continental flood basalt provinces on Earth, significantly contributed to the Late Cretaceous geodynamics of the Indian plate. Its emplacement is explained either by active rifting due to the Réunion plume or passive rifting due to successive tectonic episodes. Acknowledging that dikes serve as magma conduits, we revisit the DVP from the perspective of dikes. The Deccan dikes are classified into three major regional swarms: Narmada-Satpura–Tapi (N–S–T), Pune–Nasik (P–N), and West Coast (W-C; N–S trending). A review of geochronology, geochemistry, palaeomagnetism, and magnetic fabrics of the Deccan dikes suggests that such dikes acted as feeders for the DVP. The alignment of N–S–T and W-C dikes along crustal weak zones indicates strong tectonic imprints, while the P–N dike swarm was perhaps caused by localized stress rotations due to crustal magma chambers. Gravity modelling, randomly oriented primary magma flow axes, and magma overpressure estimations further support the existence of multiple shallow crustal chambers. We discussed the inferences made from such dikes and hypothesized that the rifting episodes since 80–90 Ma and the subsequent rapid northward migration of the Indian plate contributed to the fractures along major lithospheric weak zones. Magma coming from the Réunion plume through such fractures led to the emplacement of the Deccan dikes, which, in turn, fed the DVP.