Geochemical,mineralogical and macroscopic facies of the Fongo-Tongo bauxite deposit western Cameroon

Abstract

The Fongo-Tongo's bauxites were investigated to characterise them. Their texture varies from massive, vesicular, alveolar, conglomeratic to nodular with dominantly red colour, reddish-brown and yellow. The main minerals identified by X-ray diffraction are gibbsite and goethite with subordinate quartz, anatase, hematite, magnetite, and traces of kaolinite. The abundance of gibbsite and goethite suggested intense weathering during the formation of the bauxite deposits. Chemical data of the bauxite showed high Al₂O₃ (37.4–57.5 wt-%) with varied Fe₂O₃ (3.97–29.5 wt-%), TiO₂ (0.57–7.5 wt-%) and SiO₂ (0.48–3.21 wt-%) contents, while other oxides are generally less than 0.6 wt-% indicating high bauxite quality with low impurities. The wide range of trace and REE concentrations of Zr, Nb, Sr, V, Ce, La, Nd and the presence of both positive and negative Eu anomalies suggested and acid igneous source with mafic input. These bauxites could serve as raw material for the aluminium industry.