During this period there was abundant underground water, which dissolve small quantities of iron and silica from the sandstone.

During dry periods, the evaporation of water from the surface caused the underground water and dissolved minerals to be drawn upwards by capillary action. The minerals were deposited at the surface, where the iron formed a thin, colourful veneer over the quartz grains in the sandstone. The silica became a strong cement binding the grains together.

The process, known as laterisation, has helped shape the landscape at Rainbow Valley. The coloured zones form a hard capping that protects the softer white rock from erosion by wind and rain.

Source: NT Parks and Wildlife signage