Zoned Sedimentary Magnetites from Precambrian Banded Iron Formation of Eastern India

Electron microprobe study of low temperature zoned magnetite grains of primary sedimentary origin from the Precambrian banded iron formation (BIF) of Eastern India revealed alternate micro-bands rich in silica and iron, while minor concentration of magnesium is also found in silica-rich bands. X-ray data indicate a normal type of magnetite structure and trace element values support its primary sedimentary origin. Origin of the zoning in magnetite is attributed to enrichment of Si and Fe in alternate bands on a microscale simulating the alternate silica and iron rich bands of the host-rock-banded iron formation.