In
geography
Geography (from Ancient Greek ; combining 'Earth' and 'write', literally 'Earth writing') is the study of the lands, features, inhabitants, and phenomena of Earth. Geography is an all-encompassing discipline that seeks an understanding o ...
, an abîme is a vertical shaft in
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 ...
terrain that may be very deep and usually opens into a network of subterranean passages.
[Whittow, John (1984). ''Dictionary of Physical Geography''. London: Penguin, 1984, p. 11. .] The term is borrowed from
French, where it means abyss or chasm.
Definition
Formation
Abîmes are a structure which form late in the life of a
limestone cave. They can be 1–10 metres in diameter and up to 50 metres in height vertically. The walls have grooves that serve as a contrast to the smooth nature of the rest of the cave. They are known to lie under heads of stream valleys,
sinkhole
A sinkhole is a depression or hole in the ground caused by some form of collapse of the surface layer. The term is sometimes used to refer to doline, enclosed depressions that are also known as shakeholes, and to openings where surface water ...
s, or along non-carbonated rocks. Water will occasionally fall down the shaft, creating subterranean waterfalls. Only a small portion of the abîme connects to the rest of the cavern. They can extend to the present water table, while the rest of the cavern lies above it.
Other names
Abîme are also known as
pit caves in the United States and pot caves in England. They can also be called domepits, due to the way that looking up from below a dome can be seen and looking down from above a pit is seen.
Blue hole
A blue hole is a large marine cavern or sinkhole, which is open to the surface and has developed in a bank or island composed of a carbonate bedrock (limestone or coral reef). Blue holes typically contain tidally influenced water of fresh, ma ...
s are
sinkhole
A sinkhole is a depression or hole in the ground caused by some form of collapse of the surface layer. The term is sometimes used to refer to doline, enclosed depressions that are also known as shakeholes, and to openings where surface water ...
s that have filled with water and can occur on land or at sea. In Central America, they are called
cenote
A cenote ( or ; ) is a natural pit, or sinkhole, resulting when a collapse of limestone bedrock exposes groundwater. The term originated on the Yucatán Peninsula of Mexico, where the ancient Maya commonly used cenotes for water supplies, and ...
s.
Recreation
Rappelling (or pit caving)
This is the act of using ropes, harnesses and ladders to descend an abîme. This is the most popular activity besides the actual exploration of caves. It is also the most dangerous activity to do in a cave. The biggest danger comes from using poor ropes and ladders for rappelling down shafts. Many amateurs make this mistake and it leads to the most cave deaths.
Base cave jumping (Cave of Swallows, Mexico)
An extreme sport and requiring a person to stand at the entrance of an abîme and jump into the opening while pulling a parachute before hitting the cave floor. This is highly dangerous and should only be undertaken by those with experience. The
Cave of Swallows is the most popular due to its freefall drop, which is the longest in the Western hemisphere.
Popular examples
*
Cave of Swallows, Mexico
*
Hellhole (cave)
Hellhole is a large and deep pit cave in Germany Valley of eastern West Virginia. It is the seventh longest cave in the United States and is home to almost half of the world's population of Virginia big-eared bat, Virginia big-eared bats. At , ...
, West Virginia
* El Capitan Pit, Prince of Wales Island, Alaska
*
Vrtiglavica Cave, Slovenia
*
Pozzo del Merro, Italy (Deepest blue hole, 392m)
References
Literature
* "Cave of Swallows." ''Wikipedia''. Wikimedia Foundation, n.d. Web. 04 Dec. 2015.
* Jennings, J. N., and J. N. Jennings. ''Karst Geomorphology''. Oxford, UK: B. Blackwell, 1985. Print.
* Lübke, Anton. ''The World of Caves''. New York: Coward-McCann, n.d. Print.
* Moore, George William, and G. Nicholas Sullivan. ''Speleology: Caves and the Cave Environment''. St. Louis: Cave, 1997. Print.
* "Pit Cave." ''Wikipedia''. Wikimedia Foundation, n.d. Web. 04 Dec. 2015.
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Karst formations
Dinaric Alps
Dinaric karst formations