Petrography, geochemistry and origin of banded iron-formation of the Kazaure schist belt, Western Nigeria
The banded iron-formation (BIF) in the Kazaure schist belt (KZSB) is interbandded with muscovite schist. Other rocks in the KZSB, are gneisses, phyllites, quartzite, mica schist, carbonaceous schist, fault breccias and mylonites, granites, diorites pegmatite and tourmalinites. The BIF is composed of euhedral to subhedral magnetite, granoblastic quartz and euhedral garnet, while amphibole and ilmenite, occurring as irregularly shaped crystals, constitute the subordinate minerals (magnetite facies types). The Fe (41.50-65.88%), Mn (7.62-8.71%) and Ca (0.53-3.37%) contents of the BIF are comparable to other BIFs reported from Maru, Muro and Birnin Gwari schist belts. Lithophile elements average contents of K (9103ppm), Rb (33ppm), Sr (125ppm) and average ratios for K/Rb and Rb/Sr 207 and 0.86 respectively, and trace elements composition of Cr, Y, Rb, Sr, Co, V and Ni in the BIF indicate possible terrigenous sources of both the Fe and the SiO2, deposited in a marine environment, possibly, during the Late Achaean - Early Proterozoic period. Metamorphism of the sequence led to the concentration and enrichment of the Fe in the Fe-band possibly during the Eburnean thermotectonic event. © Nigerian Mining and Geosciences Society (NMGS).