Uncovering the hidden architecture of the Rengali Province, eastern Indian shield using high-resolution aero-geophysics, ground-gravity, structure: Insights towards geology and tectonics

Abstract

The Rengali Province is a shear zone bounded discrete domain of amalgamation among two Archean Cratons viz. the Singhbhum and Bastar cratons and a mobile belt namely Eastern Ghat Mobile belt. Based on geological evidences, it also displays an India-Antarctica connection in the past geological time-slice and supports supercontinental reconstruction. Although, the tectonothermal evolution of this province has been largely probed based on lithological, structural and metamorphic accounts, however, correlative geophysical-geology integration is absent. Hence, we analyze and interpret newly acquired high-resolution aero-geophysical data for the first time. The interpretations of high-resolution aero-geophysics, ground gravity and radiometric anomaly have been connected with geology to provide insights into tectonic evolution. Multi-scale geological-geophysical-structural analysis has been employed for understanding the subsurface architecture and contact relationship with the nearby cratons-mobile belt. Based on the aero-magnetic signature, three different zones have been delineated viz. northern, central and southern zones within the Rengali Province. The three zones are characterized by their distinct geophysical fabric and further are correlated with the geology. The gravity anomaly and modeling suggest the presence of a high-density body at mid-upper crustal depth (∼5–10 km). Three major shear zones, viz. the Barakot, Riamal and Kerajang delineate the bounding surfaces of the Rengali Province. However, the current geophysical signature indicate that the western part of the Kerajang Fault zone (KFZ) shares an inter-domain status between the Rengali Province and the Bastar Craton while the eastern part showcases an intra-domain character. Based on the complex series of magnetic fabric and anastomosing geophysical (particularly, magnetic) signature, the Rengali Province (RP) displays a classical signature of multiple accretionary histories supported by various episodic tectono-thermal activities at different time-slices.