Contribution à l'étude des systèmes karstiques gabonais. Les réseaux souterrains de la région de Lébamba (Gabon)

Abstract

Contribution to the study of karstic systems of the Lebamba region (Gabon) The Lebamba region is situated in the extreme southern part of Gabon bordering the Republic of Congo. Geologically it can be included within the Niari-Nyanga synclinoriurn where the Precambrian schists and limestones show many karstic features and particularly a remarkable subterranean network as to yet only partially explored. The dolomitic limestone of Lebamba, although of little importance, contains many cave systems : Lebamba, Bongolo et Mbenaltembe. A severe tectonic mesh together with fine micro-stratifications have opened the way to biochemical corrosion which, after observations and analysis, appears to result from a climate wetter than at present. The dimensions of the underground passages appear disproportionate relative to the low aggressivity of the present environment thus illustrating the importance of paleo-climatic factors on the morphogenesis of central african karsts.