[1] Univ Complutense Madrid, UNESCO UNITWIN Chair, Appropriate Technol Human Dev, Dept Geodinam Estratig & Paleontol,Fac Ciencias G, C Jose Antonio Novais 12, E-28040 Madrid, Spain
[2] Univ Fada NGourma UFDG, Ecole Super Ingenieurs, Fada Ngourma, Burkina Faso
[3] Univ Alcala, Unidad Docente Geol, Dept Geol Geog & Medio Ambiente, Ctra Madrid Barcelona,Km 33,600, Madrid 28801, Spain