These particular types of cave make up most of the caves in the world and the largest. Tunnels or tubes are formed in lava to make lava caves. This process occurs when the outer surface of a lava flow cools and hardens and the molten lava continues to flow which eventually drains out through the newly formed tube. The constant action of waves attacking the weaker portions of rocks lining the shores of oceans and lakes causing sea caves to form. These caves are an example of the high pressure that the waves generate and to the corrosive power of wave-carried sand and gravel.
Melted water excavates drainage tunnels through the ice to form glacier caves.
Formation of Caves At one time it was believed that caves formed near the earth's surface where the water moved downward through the cracks and pore spaces, above the satureated zone. However, this theory did not explain all cave features. It did not explain why cave passages were nearly horizontal in places where it crossed folded or tilted fault structures or how would horizontal passages form at several different or persistant levels. Just below the water table in the zone of saturation continuous mass movement of water occurs. The first stage in cave development is the dissolving of carbonate rocks and the formation of cavities and passageways.