AskDefine | Define stalactite

Dictionary Definition

stalactite n : a cylinder of calcium carbonate hanging from the roof of a limestone cave

User Contributed Dictionary

English

Etymology

σταλακτίτης (stalaktos), dripping

Noun

  1. A mineral deposit of calcium carbonate, in shapes similar to icicles, that hangs from the roof of a cave.

Translations

mineral deposit hanging from the roof of a cave

Related terms

Extensive Definition

A stalactite (Greek stalaktites, (Σταλακτίτης), from the word for "drip" and meaning "that which drips") is a type of speleothem (secondary mineral) that hangs from the ceiling or wall of limestone caves. It is sometimes referred to as dripstone.

Formation

Stalactites are formed by the deposition of calcium carbonate and other minerals, which is precipitated from mineralized water solutions. The corresponding formation on the floor underneath a stalactite is known as a stalagmite. Given enough time, these formations can meet and fuse to create columns.
Every stalactite begins with a single mineral-laden drop of water. When the drop falls, it leaves behind the thinnest ring of calcite. Each subsequent drop that forms and falls deposits another calcite ring. Eventually, these rings form a very narrow (0.5 mm), hollow tube commonly known as a "soda straw" stalactite. Soda straws can grow quite long, but are very fragile. If they become plugged by debris, water begins flowing over the outside, depositing more calcite and creating the more familiar cone-shaped stalactite.
The same water drops that fall from the tip of a stalactite deposit more calcite on the floor below, eventually resulting in a rounded or cone-shaped stalagmite. Unlike stalactites, stalagmites never start out as hollow "soda straws."
While it has been claimed that the longest stalactite known hangs in the Chamber of Rarities in the Gruta Rei do Mato (Sete Lagoas, Minas Gerais, Brazil) and is 20 metres long, vertical cavers have often encountered longer stalactites while exploring. The longest stalactite viewable by the general public is in Doolin Cave, County Clare, Ireland, in a karst region known as The Burren.
Stalactites can also form on concrete ceilings, and on plumbing where there is a slow leak and limestone (or other minerals) is in the water supply, although they form much more rapidly there than in the natural cave environment (description and experiments see literature). Stalactites can also form in lava tubes, although the mechanism of formation is much different. A common growth rate is 1 millimeter a year.

References

  • Dripstone in time-lapse ("Tropfsteine im Zeitraffer") - Schmidkonz, B.; Wittke, G.; Chemie Unserer Zeit, 2006, 40, 246.

External links

stalactite in Catalan: Estalactita
stalactite in Czech: Stalaktit
stalactite in Danish: Stalaktit
stalactite in German: Stalaktit
stalactite in Spanish: Estalactita
stalactite in Esperanto: Stalaktita kaverno
stalactite in Persian: چکنده
stalactite in French: Stalactite
stalactite in Galician: Estalactita
stalactite in Italian: Stalattite
stalactite in Georgian: სტალაქტიტი
stalactite in Hebrew: נטיף
stalactite in Lithuanian: Stalaktitas
stalactite in Hungarian: Cseppkő
stalactite in Dutch: Druipsteen
stalactite in Japanese: 鍾乳石
stalactite in Polish: Stalaktyt
stalactite in Portuguese: Estalactite
stalactite in Russian: Сталактит
stalactite in Simple English: Stalactite
stalactite in Slovak: Stalaktit
stalactite in Swedish: Stalaktit
stalactite in Turkish: Sarkıt
stalactite in Chinese: 钟乳石
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