The geochemistry and mineralogy of shales from Owutu Area, Afikpo Basin in south-eastern Nigeria have been investigated with the aim to determine the origin, mineralogy and chemical composition of shales in Owutu areas of Afikpo Basin in south-eastern Nigeria. The result of the bulk mineral composition of the studied samples shows that the clay minerals are kaolinite, illite, and smectite, whereas the non-clay minerals of the studied shales are quartz, goethite, hematite, pyrite, siderite, sylvine, ileminite and crystobalite. Kaolinite is the major clay mineral followed by montmorillonite and illite. The major non-clay minerals are quartz, and iron minerals. The result of the major oxide analysis shows that the shale samples are composed of SiO2 (41.98 to 55.31%), Al2O3 (14.9 to 19.1%), Fe2O3 (2.98 to 7.34%) and others. The Harker-type (%) variation diagrams reflect homogeneity of sediment suite and the variation in chemical constituents reflect an alteration in the mineralogy of the deposits owing to the effect of weathering. The Al2O3/TiO2 ratio suggests mafic-felsic igneous rocks as the parent rocks located in the Oban and Cameroon Massifs which is positioned east of the Afikpo Basin.
Key words: Mineralogy, Geochemistry, Owutu area, Mafic-felsic igneous rock, Oban Massif
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