Scalloping is a particular form of sculpting of the walls of

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) ...

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 through dissolution by turbulently flowing water containing dissolved

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 ...

(

carbonic acid Carbonic acid is a chemical compound with the chemical formula . The molecule rapidly converts to water and carbon dioxide in the presence of water. However, in the absence of water, it is quite stable at room temperature. The interconversion ...

). Individual scallops are shallow concave features found on many cave surfaces which are or have at some time been in prolonged contact with a water current. They typically occur in large numbers abutting one another, entirely coverings sections of cave passage, and can vary in size from less than a centimetre to many tens of centimetres or more. Their size is in inverse proportion to the speed of the current in which they formed; smaller scallops imply faster flow, larger scallops imply slower flow. Scallops are normally asymmetric with the steeper curve facing down-current. In now dry cave passages, they can therefore be used to gauge the direction of flow of the former current (in a once

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" ...

system, i.e. water-filled tube, that flow might have been downhill or uphill). Sets of scallops are examples of speleogens, which are erosional features as opposed to

speleothem A speleothem (; ) is a geological formation made by mineral deposits that accumulate over time in natural caves. Speleothems most commonly form in calcareous caves due to carbonate dissolution reactions. They can take a variety of forms, depen ...

s which are depositional features. Both are associated with

speleogenesis Speleogenesis is the origin and development of caves, the primary process that determines essential features of the hydrogeology of karst and guides its evolution. It often deals with the development of caves through limestone, caused by the prese ...

or cave-formation. Similar features can form on the walls of ice cavesthrough the action of wind.

References

Cave geology {{cave-stub