Cave Diving: Results of the Exploration of the “Combe du Creux”

This article deals with speleology applied to the exploration of a siphon named “Combe du Creux”. It is located in France, in the department of the Doubs. We present surveys and the specific forms that are encountered in this flooded cave; eventually we propose a possible evolution of this sump. Cave diving, regarded as cave science, closely associated to underwater photography, is a good mean to investigate such a cave. We have been diving in this sump since 2003 and we present the results of 13 years of explorations, up to July 2016. After having explored this cave up to the farthest known point, we made a survey (elevation and plane view). Further dives, using a rebreather when necessary, enabled a work of observation and underwater photography. We observed concretions – limestone as well as clay – and potholes below the current water level. We also observed ribs and scallops. The underground development of the cave seems well correlated with geologic elements that can be observed outside. The set of all the observations leads to the conclusion that, at long time scale, the water level has fluctuated. It has been, at least once, 46 m (151 ft) below its current position. In one place inside the cave, it has been observed interactions between flutes and scallops: this new information should be taken in account in any new theoretical or computational modeling of scallops