Palaeoarchaean sedimentation and magmatic processes in the eastern Iron Ore Group, eastern India: A commentary

The Singhbhum cratonic block, eastern India, unlike other Indian cratonic blocks, bears a continuous geological record from the Palaeoarchaean to Mesoproterozoic. The Palaeoarchaean Iron Ore Group of rocks are exposed along three distinct belts (the eastern, western, and southern) encircling the Singhbhum granitoids. The economic geological aspects of the BIF and the gold mineralization aspects of the quartz-pebble conglomerates of the Eastern Iron Ore Group (EIOG) have been discussed by a number of authors. Komatiites and basalts of the EIOG have been studied by earlier authors. However, no effort has yet been made to infer the volcano-sedimentary processes in the Eastern Iron Ore belt. This paper presents a brief overview of the sedimentation and magmatic processes in the EIOG belt. The EIOG sedimentary succession is characterized by a basal terrestrial to shallow marine deposits that progressively became deeper up section. The EIOG clastics bear carbonaceous matter. The basal terrestrial deposits (conglomerate-sandstone association) of the EIOG provide a rare opportunity to undertake fluvial architectural analysis and may enable us to unlock the peculiarities of Palaeoarchaean fluvial systems.