Most caves are formed in limestone rock. Calcite (calcium carbonate) is the main mineral of limestone.
1. Throughout time, rainwater seeps into the cracks and pores of the ground. This rainwater which absorbs carbon dioxide in the atmosphere, (and takes more carbon dioxide as it drains through soil and decaying vegetation), becomes a weak carbonic acid solution.
2. This acidic water slowly dissolves the calcite, and carves tunnels and cavities. The resulting network of passages become fully submerged or underwater caves in the limestone rock.
3. When there is climate change (ice caps form thus lowering sea level) or a tectonic uplift occurs, the water drains out of the caves, leaving dry chambers.
4. As rainwater continues to pour, dissolved limestone drips from the roof to form into stalactites, and drops to the ground becoming stalagmites.
Underwater caves are actually fully submerged sections of caves, which cave divers try to explore. Some were dry caves but due to the warmer climate melting the ice caps, sea levels rose and flooded the caves once again. The stalactites and stalagmites inside these underwater caves consequently stop growing and are now frozen in time.
Article by:
May 23, 2013.
Filipino Cave Divers 
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