Formation of the island and its geological structure
About 200 million years ago, following the movements of the massive continental plates and their mutual pressure accompanied by folding and orogeny, the Arabian Peninsula together with the African continental plate moved northward, consequently separating from Africa and joining Asia. The pressure resulting from this movement, which entered Iran from the southwest, caused the great folding of this part of the Iranian plateau into the Zagros elevations, and its mountain ranges formed perpendicular to the direction of that pressure, that is in the northwest–southeast direction. The height of the Zagros ranges gradually decreases from the Dena peak toward the Persian Gulf, and its continuation is concealed beneath the waters of the Persian Gulf as underwater folds. Kish Island and the other islands of the Strait of Hormuz in the Persian Gulf are part of the anticlines of these folds and are among the Zagros structures. Hendurabi and Lavan islands northwest and southeast of Kish are other nearby anticlines of the Zagros structures.
After its formation, Kish was from time to time submerged with changes in the Persian Gulf water level and its slight rise. The relative warmth of those times, the shallow depth of the water, abundant light and other favorable environmental conditions provided the most suitable substrate for the growth of corals, marine life and reefs, shells and other animals and aquatic organisms on the surface of the submerged island, and gradually produced a compact layer of their calcareous shell remains as coral limestones on the surface of the island immersed in water.