Study of Coal‐Bearing Heterolithic Units for Reconstructing Marine Pathways in the Eastern Gondwana Basin, India

ABSTRACT The Gondwana sequence has traditionally been viewed as resulting from post‐glacial fluvio‐lacustrine sedimentation within large, elongated rift valleys during the Permian Period. However, doubts have recently been raised regarding its freshwater origin. This research fills that gap through a multidisciplinary approach—incorporating sedimentological study, coal petrography, mineralogy and major and trace element geochemistry demonstrating a dynamic depositional environment controlled by tidal, wave and river interactions. Geochemical proxies viz: CaO/MgO, Sr/Ba and Th/U ratios, along with MgO and Al 2 O 3 trends, reveal fluctuating paleo‐salinity conditions from brackish to marine environment. The presence of dolomite, siderite, limited pyrite and alginite macerals further confirms episodic marine influence during peat formation. Heterolithic units, the principal sedimentary facies in the study area, archives tidal bundles, coarsening‐upward successions and wave‐ripple‐tidalite features, indicative of deposition across supratidal to subtidal salt marsh settings. The coal‐bearing heterolithic units form during multiple minor marine transgressions. A regressive shift is marked by the deposition of the Dumerbera and Parsatoli Sandstone units, followed by a major transgression that initiated the ironstone‐rich Barren Measure Formation. These transgressions predate the previously documented marine inundation of the overlying Barren Measures Formation, implying that marginal marine conditions developed earlier in this basin than previously thought. This study provides clear evidence of marine influence during Barakar sedimentation and supports the existence of a near‐continuous marine incursion pathway from the Khemgaon–Sikkim corridor to the Satpura Basin, reflecting sustained marine connectivity across Gondwana basins. By refining the regional paleoenvironmental model of Indian Gondwana, this study emphasises the efficacy of multi‐proxy frameworks in decoding complex depositional systems.