Publications scientifiques
2011Article de revueanglaisAccès ouvert
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Publications scientifiques
Élie Constantin Bayiga
Dieudonné Bitom
Paul Bilong
Journal of Geology and Mining Research
The study site is located in the SW of Eseka, NE of the Nyong unit. The aim of this study is the characterization of the laterites developed on amphibolites which are greenish, compact and with small discontinuous whitish quartz veins. They also possess a minor foliation. The weathering of amphibolites leads to a large lateritic cover. These laterites are essentially made up by kaolinite, goethite, gibbsite, hematite, anatase and illite. The weathering materials contain moderate to high SiO2 (11.84 to 65.91%), iron (1.73 to 35.71%), aluminium (18.49 to 31.77%) contents, weak concentrations in MgO (<1%) and CaO (< 1%). The contents of some trace transition elements are moderate. The total REE contents vary from 15 to 861 ppm with the carapace bearing the highest REE concentration (700 to 861 ppm). The weathering profile is equally marked by a strong LREE-enrichment (LREE/HREE from 3 to 318). Cerium has the highest REE contents ranging from 10 to 850 ppm. Ce/REE ratios are approximately 1. The normalized lanthanide relative to the parent rock shows large positive Cerium anomalies except in the fine saprolite with a negative Ce anomaly. The La/YbN ratios are less than 1. The mass balance assessment shows that silicon, aluminium, iron and potassium are relatively accumulated along the lateritic profile. Strontium, zinc, cobalt and yttrium are leached at the bottom of the profile contrary to rubidium, barium, zirconium, hafnium, vanadium, tin and lead which are accumulated. Most REE have been moderately leached along the profile. Key words: South-west Cameroon, amphibolites, weathering, mineralogy, geochemistry.