摘要：The Endengue iron formations (IFs) belong to the Archaen Ntem greenstones belt at the NW edge of Congo craton and comprise magnetite-bearing gneiss associated with biotite-pyroxene gneiss and intruded by biotite granite and charnockite. The studied IFs are fine-grained; weak foliated rocks, composed of quartz-pyroxene-magnetite-plagioclase mineral assemblages, suggesting high-grade metamorphism. Whole-rock geochemical composition reveals that iron and silica are the main chemical components of the studied IFs with an average TFe2O3 + SiO2 of 93.06 wt-%, suggesting the purity of the chemical precipitation. In addition, the high average Si/Al (38.69); Fe/Ti (766.83) and Fe/Al (56.36) ratios and the Fe/Ti vs Al/(Al+Fe+Mn) plot suggest that the major components (> 80%) of the Endengue IFs are predominantly hydrothermal in origin. However, the slightly high Al2O3+TiO2 content (average of 2.14 wt-%) suggested a detrital input during their deposition. The studied IF samples with an average Total Fe content of 39.40 wt-%, low gangue (34.68 wt-% SiO2 and 1.05 wt-% Al2O3) and deleterious (P2O5: 0.07 wt-%) elements contents, correspond to accepted commercial low grade siliceous ore by global standards. The Edengue IFs shared chemical similarities with other Precambrian IFs worldwide.
