Glossifungites ichnofabric signifying Crustacean colonization in early Permian Barakar Formation, Talchir Coal Basin, India

Early Permian Barakar Formation (Gondwana Super-group) in peninsular India was earlier interpreted as deposited in braided-meandering fluvial system. Intense burrowing by decapod crustaceans of marginal marine affinity led to Thalassinoides-Ophiomorpha-Rhizocorallium ichnoassemblage, belonging to Glossifungites ichnofacies, within the sandstone-mudstone heterolithic facies near the upper part of the Barakar sedimentary succession, Gouduni River, Talchir coal basin, Odisha, India. An early cementation of the sandstone-mudstone interbeds under changed salinity condition is attributed to mixing of fluvial channels with tide-wave influenced marine depositional systems. This resulted in a semi-consolidated firmground, favouring incipient crustacean colonization during prolonged phases of marine incursion within a fluvial-marine interactive estuarine system during the early Permian in eastern peninsular India.