Evidence of a Proterozoic suture along the southern part of Eastern Ghats Mobile Belt: Implications for the Nuna supercontinent

The Mesoproterozoic rocks of the Krishna Province in the Eastern Ghats Mobile Belt are situated at the edge of the Indian interior cratons and the mobile belts along the edge. We use newly acquired high-resolution gravity and magnetic along with the regional geophysical data to delineate the faults, lineaments, and subsurface boundaries between the various domains of the Krishna Province. We use this data to forward model the crustal architecture below these terranes. Our analysis shows that the Ongole domain rocks are continuing further southwards up to the Nellore and below the K–G Basin on the north side at subsurface levels. The Vinjamur and Udayagiri domains of the Krishna Province are merged into a single narrow belt known as the Nellore–Khammam Schist Belt. The joint 2D modelling of the gravity and magnetic data across these domains reveals two easterly dipping parallel thrusts separating the Dharwar–Nellore–Khammam Schist Belt and Nellore–Khammam Schist Belt–Eastern Ghats Mobile Belt, respectively. The interpreted suture between the Nellore–Khammam Schist Belt and Ongole domain of EGMB is characterized by the ophiolite and alkaline complexes of Mesoproterozoic ages. We propose that the collision between the Krishna Province and Indian Cratons occurred during the Nuna amalgamation.

The detailed crustal structure across the Dharwar Craton and EGMB was analyzed using geophysical data.