Coloration de la grotte-perte du Camp de l'Ubac (Gorges de la Jonte, Lozère, France)

Abstract

Within the framework of a master's degree dissertation on the Jonte basin, in the French département of Lozère, experiments were carried out in the highest sinkhole known of the underground course of this river. The result of the injection of the fluorescent dye into the Puits du Regard stream (Camp de l'Ubac , -13 m) on May 2nd 1990 confirmed that this stream belongs to the subterranean network of the Jonte river. After travelling approximately 9 km, the dye re-ermerged 43 hours later in the different resurgences of the Les Douzes spring. The experiment showed that the zoater travelled at a high speed : 2 00 m/h. This high speed means that the sinkhole at le Camp de l'Ubac is near the main underground collector and that the streams are neither hindered by vast reservoirs nor held by narrow passages.