What makes caves unique

These were single-celled, blue-green algae, called cyanobacteria, which made their own food through photosynthesis, releasing oxygen into the atmosphere in the process. Dolomitic limestone, a sedimentary rock, was formed over millions of years through chemical reactions generated by these early organisms. As time passed the limestone, which is permeable and soluble, was eroded by water. Weak carbonic acid in rainwater, reacting with the chemicals in the rock, dissolved and eroded away the limestone as the water filtered into the underlying depths of sediments.

Large hollow solution cavities were formed in the limestone in this way. Many cavities occur at various depths in a cave system due to the continual seepage and flow of the mildly acidic water through the deposits, while underground rivers may eventually carve their way through a mountainside, creating openings and entrances to the outside.

Humans have used caves throughout history for burial grounds, shelter, and religious sites. Ancient treasures and artifacts have been found in caves all over the world. The maximum depth a cave can reach underground is about 9, feet 3, meters. Beyond this point, the pressure from the rocks would become too great, and the cave would collapse.

The deepest cave humans have discovered is the Voronya Cave in Georgia. It is 7, feet 2, meters underground. Earth Science. Please email or share this article! Email Pin FB. Carbonic acid is found in sodas, beer, and all carbonated beverages.

This acid forms when carbon dioxide made of one Carbon and two Oxygen atoms and known as CO 2 dissolves in water. CO 2 is everywhere. It mixes with rainfall and snow melt most often in the soil. There, due to high pressures that can form within the soil, a lot of CO 2 ends up dissolved in water to make carbonic acid.

The acidified water will keep percolating downward until it reaches the limestone. Solution caves form when this acidified water has a way into the rock. This is usually through cracks, fractures, weak spots, or open places within the limestone. In a small crack the water cannot move far. It sticks to the rock wall of the crack just like it sticks to the underside of your arm in the shower.

Once the cracks enlarge and is a bit bigger, water can flow through. This brings in more acidified water and the cave begins to grow more quickly. Active streams in caves make passageways and continue to enlarge them. Bigger underground streams or rivers usually make bigger cave passages.

Streams also bring in sediments that can abrade and scour the soft limestone removing more rock and making the cave larger again. Eventually the stream exits the cave and returns to the surface as a spring. Many caves end where the river that made them flows back again onto the surface. Cave springs are important for human use.

Water can enter a cave at one point or at multiple points. When the water enters at one location this is usually as a sinking stream, where an entire creek or stream diverts underground and into a cave passage.

Sometimes there are entrances into the cave system where the water goes in. But other times the water can get into the cave through small cracks as mentioned earlier, but where there are no holes large enough for a person to enter.

When the water enters at multiple locations this is usually through sinkholes. These are circular depressions in the earth that can vary in size from a few feet to a few miles across. As lava flows downhill, its surface cools and solidifies.

Hot liquid lava continues to flow under that crust, and if most of it flows out, a hollow tube remains. Examples of such caves can be found in the Canary Islands, Jeju-do, the basaltic plains of Eastern Idaho and other places. Kazumura Cave near Hilo , Hawaii is a remarkably long and deep lava tube; it is Lava caves include but are not limited to lava tubes.

Other caves formed through volcanic activity include rift caves, lava mold caves, open vertical volcanic conduits, and inflationary caves. Sea caves are found along coasts around the world. A special case is littoral caves, which are formed by wave action in zones of weakness in sea cliffs.

Often these weaknesses are faults, but they may also be dykes or bedding-plane contacts. Some wave-cut caves are now above sea level because of later uplift. Elsewhere, in places such as Thailand's Phang Nga Bay , solutional caves have been flooded by the sea and are now subject to littoral erosion. Sea caves are generally around 5 to 50 metres 16 to ft in length, but may exceed metres ft. Corrasional or erosional caves are those that form entirely by erosion by flowing streams carrying rocks and other sediments.

These can form in any type of rock, including hard rocks such as granite.