TITLE:
Geochemistry of Muro Banded Iron-Formation, Central Nigeria
AUTHORS:
John Adeyinka Adekoya, Chukwuemeka Tony Okonkwo, Mohammed O. Adepoju
KEYWORDS:
Muro Iron-Formation; Oxide Facies; Carbonate Facies; Geochemistry; Central Nigeria
JOURNAL NAME:
International Journal of Geosciences,
Vol.3 No.5,
November
29,
2012
ABSTRACT: 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.