Crustal Structure of the Intra-cratonic Chhattisgarh Basin and the Adjacent Eastern Ghats Mobile Belt, East-Central India

The Chhattisgarh Basin in central India is one of the largest Meso-Neoproterozoic intra-cratonic Purana basins. This basin has long been the subject of debate concerning its origin and tectonic evolution. Although its geological and depositional framework are relatively well constrained, the deep crustal architecture and present-day tectonic setting remain less understood. In this study, we employ broadband seismic data from a temporary network of 30 seismic stations deployed across Chhattisgarh Basin and the adjoining Eastern Ghats Mobile Belt (EGMB) to investigate the crustal structure beneath the Chhattisgarh Basin, adjoining Gondwana sediments, the Bastar Craton and the EGMB. Receiver function analysis yields several key observations such as (a) a thin, sharp and nearly flat Moho beneath the Chhattisgarh Basin and Bastar Craton, with an average depth of ~ 37 km and clear multiples, indicating a relatively undisturbed crustal fabric; (b) seismic images beneath the Chhattisgarh Basin do not support models of intra-cratonic rifting or foreland basin development, but instead suggest that sedimentation was possibly due to sea-level fluctuations and the progressive infilling of localized topographic depressions within the Bastar Craton; (c) the Central Indian Shear (CIS) exerts a strong influence on Moho geometry, expressed as a gentle northward dip into the Archean craton segment across the basin–craton boundary, and slightly reduced average shear-wave velocities within the basin; (d) a gradational Moho is detected beneath Gondwana sediments along the north-eastern fringe of the basin; and (e) beneath the EGMB, pronounced Moho offsets of up to ~ 5 km and an eastward dipping gradational Moho delineate significant crustal heterogeneity and bear signatures of an ancient subduction system. These findings provide new constraints on the crustal architecture of the Chhattisgarh Basin and its adjoining tectonic domains, offering valuable insights into the geodynamic processes that shaped central India’s intra-cratonic basins.