ALBERT

Description: The central-western Indian region of the Indian shield encapsulates the Archean to recent tectonic evolution history of the Indian subcontinent. The iconic vast Deccan flood basalt cover, produced by the youngest (~65 Ma) thermal plume (Reunion) uprising under the Indian lithosphere, and Proterozoic to Quaternary sedimentary formations mostly obscure the Precambrian geology and lithosphere scale alterations induced by Phanerozoic tectonothermal events in the region. Therefore, the deep probing magnetotelluric (MT) geophysical tool is employed to image the lithosphere architecture for the purpose of unraveling the mysterious subsurface geology and unfolding the tectonic history of the region. Besides, the study aims to map any major upper mantle pathways of the Deccan magma ascent for which no explicit geophysical revelation yet made. A holistic three-dimensional (3D) lithospheric resistivity model for the central-western India, obtained from 3D inversion of long-period MT and tipper data at 146 stations with ~50 km grid spacing, showed two important high conductive (〈30 Ωm) pipes commencing from a common deep mantle conductive zone imaged below the northernmost lobe of Deccan volcanic province (Malwa plateau) and its proximity. These are interpreted to be the melt rich deeper mantle zone related to the Deccan plume upwelling and hitherto unknown primary magma ascent channels through the lithosphere. High to moderately conductive crustal zones and weak to moderate lithospheric mantle resistivity in most parts of the study region denote an intense alteration in the Precambrian lithosphere due to multiphase tectono-magmatic episodes that affected the central-western India from the Neoproterozoic to Cretaceous-Paleogene boundary.