Genesis of Meka’a Geophagic Kaolin Deposit (In Foreke-Dschang West Cameroon)
S. A. Douola Ninla
Department of Earth Sciences, Faculty of Sciences, University Dschang, P. O. Box 67, Dschang, Cameroon.
G. Kieufack
Department of Earth Sciences, Faculty of Sciences, University Dschang, P. O. Box 67, Dschang, Cameroon.
I. Y. Bomeni
Department of Civil Engineering, Fotso Victor University Institute of Technology of Bandjoun, P. O. Box 134, Bandjoun, Cameroon.
M. Gountié Dedzo
Department of Life and Earth Sciences, High Teachers’ Training College, University of Maroua, P. O. Box 55, Maroua, Cameroon.
A. S. L. Wouatong *
Department of Earth Sciences, Faculty of Sciences, University Dschang, P. O. Box 67, Dschang, Cameroon.
*Author to whom correspondence should be addressed.
Abstract
Geological, mineralogical and geochemical studies where carried out on Meka’a kaolin deposit located in Foréké-Dschang in order to define the ore genesis. Three kaolin facies (yellow, red and white) and isalteritic components were characterized by different methods including morphostructural description, XRD, XRF, ICP-MS, SEM-EDS, heavy mineral research and organic matter contents. The results show that all these kaolins are based on kaolinite (87–90%) associated with more or less significant phases of orthoclase (1-2%), goethite (0.5-3.5%), quartz (1-1.5%), anatase (1.2-2%) and hematite (1-2%). Small amounts of illite (3.5%) was found only in white facies. The scanning electron microscope (SEM) pattern shows that kaolinite particles contained in these kaolins are very small (<2 µm) and are poorly crystallized due to the impurities they contain. Meka’a kaolin’s are extremely weathered (CIA and CIW ≈ 100) and their organic matter content is considerable (1.82-2.54%) and is explained by the presence of carbonized wood in the ignimbrites. The combination of different analytical techniques points out a meteoric weathering of ignimbrite under oxidizing conditions as being of petrogenetic origin of this kaolin deposit.
Keywords: Cameroon, clays, hydrothermal alteration, Kaolin, meteoric weathering protolith.