Tectonic Architecture of the Southern Indian Shield Region: 3D Magnetotelluric Imaging of Plume Signature and Subduction Polarity

The lithospheric resistivity structure beneath the Southern Indian Shield Region (SISR) was imaged using three‐dimensional magnetotelluric inversion across 32 stations along an approximately 800 km long and 390 km wide, NW–SE profile spanning the Deccan Volcanic Province (DVP), Western Dharwar Craton (WDC), and Southern Granulite Terrain (SGT). Incorporating both diagonal and off‐diagonal impedance elements, the study overcame limitations of 2‐dimensional models in this geologically complex region. The resistivity structures in integration with geological and other geophysical studies reveal a southward subduction polarity beneath the Palghat‐Cauvery Suture Zone (PCSZ). The model indicates north‐to‐south lithospheric thickening, with the Moho near 48 km and the minimum lithosphere‐asthenosphere boundary at around 170 km depth. The findings, supported by plume‐ and subduction‐derived models, illuminate the transition from plume‐driven vertical tectonics to horizontal plate tectonics and the role of lithospheric cooling during the Archean in craton stabilization. This work advances the understanding of Precambrian tectonic processes and lithospheric architecture beneath the southern Indian shield. Similar patterns of plume–subduction interactions and craton stabilization have been documented in other ancient cratons such as the Kaapvaal (South Africa), Pilbara (Australia), and Superior (Canada), suggesting that the processes observed beneath the Southern Indian Shield may reflect globally recurrent mechanisms during early Earth or past tectonic evolution.