Stop n. 6

"Fossil entrance of the Stampu 'e Pireddu branch"

This stop is only a few meters before the cave ramification called “Stampu e Pireddu” and its modern entrance, and we are in front of what once was the entrance of the ramification. We can soon realize that the hole is been completely closed by deposition material and formations, but it is another important evidence of the many phases the cave went through. In sequence, we can see at first the exit, opened by a massive amount of water with high pressure. This first phase was followed by a second phase with variable flows, which have deposited a bed of alluvial materials, sometimes of considerable size. Some of this material is granite, a rock transported from over 12 kilometres away. The third phase is characterized by powerful formations covering these deposits, followed again by slower phase, with water flowing on the river level. In these last few seconds, we have travelled over millions of years of geological evolution.