Phénomènes karstiques fossiles et actuels au sein des formations métamorphiques silico-alumineuses de la nappe pan-africaine de Yaoundé (Sud-Cameroun). Fossil and present-time karstic phenomena in silico-aluminous metamorphic formations of the Pan-African nappe of Yaoundé (South-Cameroon)

Jean-Paul Vicat (1) , Hubert Mvondo (2) , Luc Willems (3) , André Pouclet (1)

1 ISTO - Institut des Sciences de la Terre d'Orléans
2 Département de géologie, université de Yaoundé-1
3 Laboratoire de sédimentologie, Dpt Géologie-Pétrologie-Géochimie

Numerous karstic features have been recognised in the non-carbonaceous micaschists and gneisses of the Yaoundé Pan-African nappe, south of Cameroon. It is shown that their formation was controlled by the structural features of the rocks. The wells and the pipes in the bedrock outcrops point out a current karstification process, resulting from the plagioclase dissolution by the acid rain waters. Hill wall alveoli and caves, of pre-Miocene age, are exhumed features that were done by dissolution in the aquiferous underground.

Mots clés: silico-aluminous karst; dissolution; structural control; Pan-African

Domaines: Paléontologie

Jean-Paul Vicat, Hubert Mvondo, Luc Willems, André Pouclet. Phénomènes karstiques fossiles et actuels au sein des formations métamorphiques silico-alumineuses de la nappe pan-africaine de Yaoundé (Sud-Cameroun). Fossil and present-time karstic phenomena in silico-aluminous metamorphic formations of the Pan-African nappe of Yaoundé (South-Cameroon). Comptes Rendus Géoscience, 2002, 334, pp.545-550. ⟨10.1016/S1631-0713(02)01791-1⟩. ⟨hal-00077604⟩