Banded Iron Formation: Petrology

Banded Iron Formations (BIF) is one of the unique and important rock types in the Archaean greenstone belts and Proterozoic metasedimentary series. They occupy a unique position in the sedimentation history of this time range, as they have no modern analogues. This virtual confinement of BIF in space and in time has made them extremely useful for the understanding of the Precambrian exogenic processes and the atmospheric - environmental changes that occurred during the early history of the earth. The BIF are described with different names in different parts of the world such as, Taconite - U.S.A.; Jaspilite - Australia; Itabirite - Brazil. BIF are of economic interest as they host the worlds largest iron ore deposits. There are several major aspects related to the origin and evolution of BIF for which no satisfactory and generally agreed explanation are available. Various genetic models have been proposed which, however, differ considerably from each other. The divergent conclusions of these workers bring to the fore, the problem of deciphering the origin of BIF in Nigeria and how they relate to other major BIF occurrences of the world. The workers differ in their conclusions rega