Recognition, Correlation and Age of Erosion Surfaces in the Iron Ore Ranges of Bihar and Orissa

In the Iron Ore Ranges of Bihar and Orissa, three erosion surfaces have been recognised around 3000-2700 feet, 2300-2000 feet and 1600-1400 feet above M.S.L., based on model studies in the laboratory, and the relative positions in the field of the residual deposits of laterites and lateritic iron and manganese ores. These have been correlated with those in the neighbouring areas in the southeastern Chota Nagpur and the Simlipal massif in Bihar and Orissa respectively. Based on the study of sedimentary record in the adjoining Bengal Basin, the tentative ages assigned to them from the top are Upper Jurassic to Lower Cretaceous, Upper Eocene and Upper Miocene.