How are tufa towers formed?

Tufa towers are columns of calcium carbonate which form in carbonate-rich saltwater lakes (soda lakes). Underneath the lake, underwater springs pump calcium-saturated water through the lake bed.

When the spring water meets the alkaline lake water, calcium and carbonate salts react to form insoluble calcium carbonate (limestone), which precipitates out, settling in mineral deposits around the spring.

Over centuries these deposits gradually grow into towering columns which can reach heights of up to nine metres (30 feet). Tufa can only form underwater, so it is only if lakes are drained or dry out over many years that the towers are exposed.

Answered by Alexandra Cheung