1. School of Geology and Mining Engineering University of Ngaoundere Meiganga Cameroon
2. Department of Earth Sciences Faculty of Science University of Yaounde I Yaoundé Cameroon
3. Université Côte d'Azur, CNRS Observatoire de la Côte d'Azur, IRD, Géoazur 06560 Valbonne France
4. National Advanced School Engineering of Maroua University of Maroua Maroua Cameroon
5. Department of Physics, Faculty of Science University of Yaounde I Yaoundé Cameroon
6. School of Polytechnic of Conakry E.P.C. Geology and Mining Engineering Conakry Guinea