Contrasted mineralogical composition of the laterite cover on serpentinites of Nkamouna-Kongo, southeast Cameroon

摘要: Four drill cores along a lateritic hill in Nkamouna-Kongo (southeast Cameroon) were studied using microprobe analysis, X-ray diffraction, scanning electron microscopy, transmission microscopy and infrared spectroscopy. The main objective of the study was to investigate occurrence clay silicates while evaluating Ni-Co content laterite for potential mineral exploitation. thick profiles (>40 m deep) developed on serpentinized ultramafic rocks have an Fe-rich clayey fraction, with goethite as mineralogical constituent secondary quartz relicts magnetite-maghemite accessory minerals. Silicate clays are less abundant occur mainly towards top profiles. At summit interfluve, kaolinite some gibbsite associated goethite. Along slopes, at bottom profiles, weathered bedrock shows presence smectite (Fe-beidellite) kaolinite, probably due slower water-flow conditions. Towards profile lower clay, ferruginous upper horizons, only remains gibbsite, after leaching silica soluble cations following repeated remobilization-recrystallization processes. summit, where downward movement water is rapid, no identified. As whole, composition material varies close relationship drainage, leading contrasted mineralogy marked by Fe-beidellite bottom, that