Proterozoic crustal evolution of the eastern Vindhyan basin, central India: Constraints from geophysical and geochronological data

Abstract

The Vindhyan basin is one of the major Proterozoic basins in the Indian shield bounded by Central Indian Tectonic Zone (CITZ) in the south and Bundelkhand craton in the north having thick sedimentary succession. Interaction of basin with CITZ and its imprints on regional crustal structure is important to understand its evolution. In this study, a detailed interpretation of gravity and aeromagnetic anomaly maps with constraints from multi-channel seismic data is carried out in the Son valley part of the Vindhyan basin to identify its structural links with the surrounding tectonic domains. The 3-D gravity inversion along with 2-D gravity and magnetic modelling helped to delineate the crustal architecture and Moho geometry which reveal that the Moho below the basin varies between 38–46 km with the deepest Moho in southern part along its boundary. The crustal models in the study area further reveal i) higher density and magnetization for lower Vindhyan sediments because of intrusive rocks/ volcano clastic sediments, ii) the eastern part of basin is devoid of crustal underplating iii) basement high, complex rift tectonics and basin tilting in Damoh region, iv) undulating crustal layers intervened by deep crustal faults in the southern part of the basin and the CITZ region, and v) the Bundelkhand Tectonic Zone and Madaura Shear Zone in the craton are characterized by deep crustal faults. In this paper, we propose a geodynamic evolutionary model of the Vindhyan basin which reveals opening of the basin subsequent to the formation of CITZ during ∼ 2000–2200 Ma. The basin sediments were deposited in multiple stages during 1700–1000 Ma followed by the basin closure during 1000–750 Ma. Hence, it is inferred that the post tectonic activity of the CITZ affected the Son Narmada fault zone and facilitated the opening of Vindhyan basin during the Paleoproterozoic period.