Abstract:
Karstification is a dissolving process which enlarges some channels clefts and fractures and eventually creates caves. The phenomenon Is only possible in deep areas located under the base level, if water flows easily. The analysis of the physical and chemical data accumulated at the beginning of the flood shows hotter and more mineralised waters once the flow starts accelerating. The hydrodynamic study of the phenomenon allows to build a model that explains the deep karstification process. The deep karstification process occurs when a very heterogenous distribution of pressures briefly takes place in the aquiferous system at the beginning of the recharge. This is due to the fact that the waters reach the karstic conduits at different times and therefore the refill and the eviction of waters do not occur uniformly in the saturated zone. Actually, the very mineralised waters located under the base level in the caves, conduits and other holes are evicted first. Then, these waters are replaced by aggressive waters, which are often with a high C02 concentration. As a result, the limestones dissolution process starts again in the area under the outlet point and the splits and bed ding joints keep on enlarging. The heterogeneous distribution of pressures also opens new splits through a corner effect and leads to the development in depth of the karstification process.