Sedimentary petrography and ichnology of the Barail Group along the Old Cachar road, Manipur, India

The Oligocene Barail Group represents a significant lithostratigraphic unit within Paleogene-Neogene successions of northeast India. Integrated sedimentologic and ichnologic analyses along the Old Cachar road, Manipur, have been carried out. Sedimentological investigation reveals a dominance of subarkoses and arkoses, with source rocks being granites, pegmatites, gneiss, and schists, typical of a warm, humid to subhumid palaeoclimate. The ichnofauna points to a depositional environment ranging from upper shoreface through tide-dominated delta front up to the lower shoreface zone, characterized by Teredolites , Glossifungites , Skolithos , Skolithos-Cruziana , and Cruziana ichnofacies. The Barail sequences represent a hyperpycnal-delta-fed sedimentary unit, deposited at the continental margin in the passively rifted western Burma basin which evolved due to magma-poor hyperextension.