Pamukkale's terraces are made of travertine, a sedimentary rock deposited by water from the hot springs.
In this area, there are 17 hot water springs in which the temperature ranges from 35 °C (95 °F) to 100 °C (212 °F). The water that emerges from the spring is transported 320 metres (1,050 ft) to the head of the travertine terraces and deposits calcium carbonate on a section 60 to 70 metres (200 to 230 ft) long covering an expanse of 240 metres (790 ft) to 300 metres (980 ft). When the water, supersaturated with calcium carbonate, reaches the surface, carbon dioxide degases from it, and calcium carbonate is deposited. The depositing continues until the carbon dioxide in the water balances the carbon dioxide in the air. Calcium carbonate is deposited by the water as a soft jelly, but this eventually hardens into travertine.