Diagenetic Crystallisation and Migration in the Banded Iron Formations of Orissa, India

Unmetamorphosed iron formations of the youngest stratigraphic sequence in Orissa, India, were studied for diagenetic features. Attention was concentrated on the oxide and carbonate facies of the iron formation only. Silica (chert), hematite and siderite are primary minerals which show evidences of more than one period of diagenetic crystallisation and migration. The study suggests an early to late diagenetic time during which all the features were produced. It also reveals that carbonate facies is much more important in the study of iron formation than hitherto appreciated.