BANDED IRON FORMATION'S - RULE THEM AND RULE THE WORLD OR THE SKYSCRAPERS Muro Banded Iron-Formation occurs in the Proterozoic Toto Schist Belt, central ... iron Formations (Regional Representations), Theophrastus, Athens, 1990

Muro Banded Iron-Formation occurs in the Proterozoic Toto Schist Belt, central Nigeria. It consists preponderantly of oxide facies and minor carbonate facies. The oxide facies is made up of alternating bands of quartz (metachert) with those of hematite + magnetite + martite ± goethite, chlorite, pyrrhotite and garnet. The carbonate facies consists of quartz (metachert) + siderite ± goethite. In the oxide facies the total iron content (Fe₂O₃t) ranges from 33.95% to 48.08% and the SiO₂ content from 50.33% to 64.50%. In the case of the carbonate facies, the Fe₂O₃t content varies from 15.42% to 20.66% and SiO₂ content from 66.84 to 72.86%. The Al₂O₃ content is generally low ranging from 0.1% to 0.54% in the oxide facies, and 0.24% to 0.31% in the carbonate facies. Chemically, the Muro Iron-Formation is similar to the Lake Superior-type iron-formations in terms of the distribution of the major and trace elements. This taken together with similarities in lithological associations indicates its deposition in similar environments i.e. shallow intra-continental or restricted/barred marine basin. The very low Al₂O₃ contents indicate minor clastic dilution of the original chemical precipitates.