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Abstract

The Precambrian terrains of the Northwest Indian shield (NWIS) comprises of the Bundelkhand, Marwar and Dharwar cratons with intervening mobile belts such as the Aravalli Delhi fold belts (ADFB) and the Central Indian tectonic zone (CITZ). The region is also characterized by the presence of Proterozoic/phanerozoic rift basins such as the Vindhyan (VB), Cambay rift (CR) and Kutch rift (KR) with significant area covered by the Cretaceous flood basalts of the Deccan Volcanic Province (DVP). In this study, we present the results of a seismically constrained multi-scale geopotential field interpretation along two long corridors that cut across the major Precambrian terrains of the NWIS. The lithosphere architecture across these terrains in correlation with the structural geological and geochronological data allowed us to generate the robust geodynamic models of evolution. The joint interpretation of gravity and magnetic anomalies in the NWIS region reveal that the ADFB and CITZ are bounded by deep crustal faults having denser crustal rocks, shallow Moho below DVP and CR with the presence of thick underplated layer at the base of the lower crust below most of the NWIS region indicating a strong magmatic imprint. The distinct crustal structure and the deeper LAB below the ADFB and CITZ reveal the signatures of Proterozoic amalgamation. Further, these characteristics are used to build the geodynamic models for the lithosphere evolution in the NWIS region.