Karst in granitic rocks, South Cameroon: cave genesis and silica and taranakite speleothems |
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| Authors: | L Willems Ph Compère F Hatert A Pouclet J P Vicat C Ek F Boulvain |
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| Institution: | Unitéde Pétrologie Sédimentaire, Département de Géologie, B20,;Departement de Géographie Physique, B11, Universitéde Liège, B-4000 Liège,;Laboratoire de Biologie générale et de Morphologie ultrastructurale, Institut de Zoologie, Bât. I1, Service collectif des enseignements de biologie en candidature, Universitéde Liège, Quai Van Beneden, 22, B-4020 Liège,;Laboratoire de Minéralogie, B18, Universitéde Liège, B-4000 Liège, Belgium;;Universitéd' Orléans, Facultédes Sciences &UMR 3113, BP 6759, 45067 Orléans Cedex 2, France |
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| Abstract: | ABSTRACT A cave in granitic rocks was studied in Mezesse, South Cameroon. Coralloid speleothems, draperies and dissolution traces on the cave walls attest to its truly karstic nature. The speleothems consist of microlayers of opal and taranakite (K,NH4)Al3(PO4)3(OH).9H2O. They indicate a significant mobilization of silica, Al and K from granite during the formation of the cave. Identification of silicified bacteria in the speleothems layers suggests a possible role of these micro-organisms in silica deposition. The presence of taranakite and of silicified organic remains within the speleothems lead to a better understanding of the genesis of the cave. |
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