Pamukkale - Limestone Terraces

The calcareous deposits (travertine) come from a number of warm water springs (34-35°C/93-95°F) which contain large quantities of dissolved calcium bicarbonate. When the water reaches the surface, the calcium bicarbonate breaks down into carbon dioxide, water and calcium carbonate. The latter is deposited in the form of a hard grayish-white layer. These deposits gradually fill up, sometimes even raise the water channel, so that the water flow disperses in all directions and the deposits produce a series of fan-like formations with small dips and terraces. In the same way that stalactites form in limestone caves, the deposits grow on the steep slopes eventually taking on the appearance of cotton wool. Çalcareous deposits can be found wherever water emerges from karst rock, e.g. Lake Plitwitz in Croatia and near Antalya in Turkey. The thermal spring water, which in addition to chalk and carbon dioxide, contains sulfuric acid, sodium chloride, iron and magnesium, has long been valued for its healing powers and thus revered as a shrine.