How is a limestone cave formed?

Answer 1

Limestone is a sedimentary rock made up of calcite (CaCO3) as its main mineral. Some limestones were formed by chemical deposition and others by the accumulation of shells from minute sea creatures. Many invertebrate animals (animals with no backbones) take calcite from sea water to construct their shells. When they die the shells fall to the sea bed. Areas where there is little deposition of mud or sand will be ideal for the formation of limestone. One type of limestone which is very pure is called chalk, but most other limestones contain variable amounts of mud or sand or other material.

Answer 2

Limestone dissolves under the action of rainwater and groundwater charged with H2CO3 (carbonic acid) and naturally occurring organic acids. The dissolution process produces a distinctive landform known as karst, characterized by sinkholes, sinking streams, and underground drainage. Limestone caves are often adorned with calcium carbonate formations produced through slow precipitation. These include: flowstones, stalactites, stalagmites, helictites, draperies, soda straws and columns. These secondary mineral deposits in caves are called speleothems.

Answer 3

The majority of limestone is thought to be formed by biogenic means. Microscopic organisms remove CO2 and Ca from seawater, convert the CO2 to the carbonate radical (CO3 2-) and form exoskeletons from the synthesized CaCO3. When the organisms die, these exoskeletons fall to the sea floor where they are preserved as limestone.

Answer 4

the calcium in limestone degrades ans a cave is formed

Answer 5

From lithification of calcium carbonate organic sediments in a marine environment.