The Al Khiran coast is shaped mainly by the erosional influences of wind, rain and sea. The action of the sea slowly wears away at the base of the cliffs of these relatively soft rocks; undercutting them to an extent where eventually sections of the rock face are left unsupported and collapse into the ocean. The process then starts again on the new section of cliff wall.
In addition much of the surrounding rock at or near the surface has been karstified; that is rock that has been affected by a dissolving process. Most of Al Khiran’s rocks are limestone; they contain calcite a mineral which can be dissolved by carbonic acid.
This dissolving process mostly occurred long ago, during cyclic periods when Oman’s climate was much wetter than it is today. The last wet phase occurred between 11,000 and 6,000 years ago.
Wetter climates allow plants to grow and soil to be produced. Carbon dioxide in the soil mixes with rainwater to produce a weak solution of carbonic acid. As the water enters the cracks and fissures in the limestone it reacts with calcite in the rock, dissolving it; in this case only small holes have been dissolved, however in other parts of Oman, time and circumstance has allowed the development of huge caverns.