Calcium carbonate
In this area, there are 17 hot springs with temperatures ranging from to . The water that emerges from the spring is transported to the head of the travertine terraces and deposits calcium carbonate on a section long covering an expanse of to . When the water, supersaturated with calcium carbonate, reaches the surface, carbon dioxide de-gasses from it, and calcium carbonate is deposited. Calcium carbonate is deposited by the water as a soft gel which eventually crystallizes into travertine.