Marine Influence in the Indian Gondwana Basins: A Review from Ichnological Findings

Ichnological findings from the Indian Gondwana basins provide a new insight into the role played by the ancient sea in shaping Upper Palaeozoic-Mesozoic geohistory. The ichnocoenoses with high density and diversity define typical shallow marine ichnozones and ichnofacies (Skolithos and Cruziana) recurring as thin tongues within continental deposits and, at times, clearly separating coal-bearing cyclic deposits. In the same way, as documented in other Gondwana fragments, these ichnofacies tongues in conjunction with complementary marine invertebrate body fossils, unquestionably suggest strong infaunal activities and short-lived shallow marine incursions, the most conspicuous of which are noted within the Talchir and Barakar Formations. They also split the coal seams into transgressive-regressive couplets, a very common feature of shallow marine lower deltaic (paralic) coal deposits.