Stop n. 4

"Flow stones"

Now the cave takes again is natural direction, with faults reaching west. It is clear in the section how the flow of dripping water comes from East through the main fracture between the faults, as all the main formations appear on the right side. Notice here how the river under dug the alluvial material which once stood as sub layer for the cave’s pavement. Today’s formation appears to be hanging. Here we start seeing many rimstone formations. Rim stones form when the water laying on the surface does not reach high levels of oversaturation, not allowing calcium carbonate to seat over the pavement surface. However, if the movement of water becomes wavy rather than flat, oversaturation happens in specific areas forming the rims, which contain the water. The inclinations of the rocky surface gives a decreasing aspect to the rimstone formations. The shape of rimstones can vary according to the different sources of water. In San Giovanni’s cave, the supply of water is heavy and fast, giving the rimstone a more regular and simple shape.