Speleogenesis is the origin and development of

cave Caves or caverns are natural voids under the Earth's Planetary surface, surface. Caves often form by the weathering of rock and often extend deep underground. Exogene caves are smaller openings that extend a relatively short distance undergrou ...

s, the primary process that determines essential features of the hydrogeology of

karst Karst () is a topography formed from the dissolution of soluble carbonate rocks such as limestone and Dolomite (rock), dolomite. It is characterized by features like poljes above and drainage systems with sinkholes and caves underground. Ther ...

and guides its evolution. It often deals with the development of caves through

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

, caused by the presence of water with

carbon dioxide Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at norma ...

dissolved within it, producing carbonic acid which permits the dissociation of the

calcium carbonate Calcium carbonate is a chemical compound with the chemical formula . It is a common substance found in Rock (geology), rocks as the minerals calcite and aragonite, most notably in chalk and limestone, eggshells, gastropod shells, shellfish skel ...

in the limestone.

Limestone

The majority of limestone caves are formed by

dissolution by the solvent action of meteoric waters circulating through the rock. In the presence of carbon dioxide saturated water, calcium carbonate reacts to form the soluble calcium bicarbonate. :CaCO₃ + CO₂ + H₂O → Ca(HCO₃)₂ As meteoric waters precipitate they dissolve atmospheric carbon dioxide to form a dilute carbonic acid solution, which builds up in permeable fissures, bedding planes, joints, and faults within limestone rocks. The exposed limestone then reacts to become calcium bicarbonate which dissolves in the water and is removed from the fault as the solution flows away.

Phreatic ''Phreatic'' is a term used in hydrology to refer to aquifers, in speleology to refer to cave passages, and in volcanology to refer to a type of volcanic eruption. Hydrology The term phreatic (the word originates from the Greek , meaning "well" ...

passages develop in conditions of complete water-fill meaning that ceilings and walls may be eroded as readily as floors. The form is generally that of an ellipse along the host fissure, whilst more circular forms generally indicate faster solvent flow and deep pockets are often indicative of slower flow. Vadose passages develop where the water has a free surface (i.e., in the vadose zone), and are varieties of entrenched, canyon-like channels as found with surface rivers. It is common to see a younger canyon entrenched in the floor of a phreatic passage, signifying a lowering of the

water table The water table is the upper surface of the phreatic zone or zone of saturation. The zone of saturation is where the pores and fractures of the ground are saturated with groundwater, which may be fresh, saline, or brackish, depending on the loc ...

. Scalloping of cave surfaces may arise in passages of either type as dissolution occurs, further enlarging the passage.

References

External links

Exploring Earth: Observe an animation of cave formation
an animation of cave formation in limestone deposits.

an interactive explanation of how rain, waves, lava, and bacteria can form caves.
Speleogenesis.com
- a communication platform for physical speleology and karst science research. Cave geology {{caving-stub

Limestone

See also

References

External links