Chromite Enrichment in the Recent Fluviatile Sediments, North Iraq

Abstract

The Recent sediments from North Iraq are characterized by a higher content of chromite. This paper deals with the mineralogy and geochemistry of chromite in the heavy mineral assemblages from Recent fluvial sediments in an attempt to elucidate its distribution and source rock. The heavy fraction is composed of iron oxides and chromite forming about 50% of the total heavies. Chromite forms up to 80% of the opaque minerals at some areas in North Iraq. The non-opaque heavy minerals are composed of epidote, garnet, tourmaline, rutile, staurolite, kyanite, zircon, olivine, chlorite, muscovite, pyroxene and am-phibole. XRD analysis revealed that chromites are mainly aluminian chromite. Geochemical study shows that chromite is depleted in Fe and enriched in Al, such enrichment being related to the effect of alteration that leaches iron from chromite in the presence of suitable conditions assisting this alteration. Chromite is akin to podiform Alpine-type chromites. Higher concentration of chromite favours the addition of ophiolite complex of the Zagros-Taurus belt as well as recycling of chromite from older formations in North Iraq. Another factor controlling this obvious enrichment of chromite is the hydraulic equivalent and meandering morphology of the rivers.