Karst is the topography formed from dissolution of dissolved rocks such as limestone, dolomite, and gypsum. It is characterized by an underground drainage system with sinkholes and caves. It has also been documented for more weatherproof rocks, such as quartzite, given the exact conditions. Underground drainage can limit surface water, with little or no rivers or lakes. However, in areas where dissolved bedrocks are covered (possibly by debris) or bounded by one or more insoluble rock layers, typical karst characteristics can occur only at subsurface levels and are completely lost on the ground.
The study of karst is considered very important in petroleum geology because as much as 50% of the world's hydrocarbon reserves are held in porous karst systems.
Video Karst
Etimologi
The English word
The common Slovenian noun kras was first proved in the 18th century, and its adjective forms a kra? Ki in the 16th century. As a proper noun, the Slovenian form of Grast was first demonstrated in 1177, referring to the Karst Plateau - a region of Slovenia that partially stretches to Italy, where the first research on karst topography was performed. The Slovenian words appear through metathesis of the reconstructed form * kors? , borrowed from Dalmatian Romance carsus . Ultimately, the word comes from the Mediterranean, believed to originate from some of the romanized bases of Illyria. It has been suggested that the word may be derived from Proto-Indo-European root karra - "rock". The name can also be linked to oronym Kar (u) sÃÆ'¡dios oros quoted by Ptolemy, and possibly also to Latin Carusardius .
Maps Karst
Initial study
Johann Weikhard von Valvasor, a pioneer of karst studies in Slovenia and a fellow of the Royal Society for Improving Natural Knowledge, London, introduced the karst to European scholars in 1689, describing the underground river phenomenon in his account of Lake Cerknica.
Jovan Cviji? very advanced knowledge of the karst region, so much so that he is known as "the father of karst geomorphology". Mainly working with karst areas in the Balkans, Cviji? 1893 publications Das KarstphÃÆ'¤nomen describes landscapes such as karren, dolines and poljes. In Cviji publication 1918? proposed a cyclical model for the development of karst landscapes. Hydrology Karst emerged as a discipline in the late 1950s and early 1960s in France. Previously, cave explorers, called speleologists, have been dismissed as more of a sport than science, which means that underground karstic caves and their associated waterways, from a scientific perspective, are studied.
Chemistry
The development of karst occurs whenever acidic water begins to break the surface of bedrock near its crack, or bedding. Because the bedrock (usually limestone or dolostone) continues to decline, the cracks tend to enlarge. Over time, these fractures will become more widespread, and eventually drainage systems of some kind can begin to form underneath. If this underground drainage system is established, it will accelerate the development of karst formation there because more water will flow through the area, giving it more erosive power.
Dissolution mechanism
The carbonic acid that causes the karstic features is formed when rain passes through the atmosphere takes carbon dioxide (CO 2 ), which is soluble in water. After the rain reaches the ground, it can pass through a soil that can provide more CO 2 to form a weak carbonic acid solution, which dissolves calcium carbonate. The main reaction sequences in lime dissolution are as follows:
Particularly and extremely rare conditions as found in the past at the Lechuguilla Cave in New Mexico (and more recently in the Frasassi Cave in Italy), other mechanisms may also play a role. Oxidation of sulfides that lead to the formation of sulfuric acid can also be one of the corrosion factors in karst formation. As the oxygen (O 2 ) - the rich surface water permeates into the deep anoxic karst system, they carry oxygen, which reacts with the presence of sulphides in the system (pyrite or hydrogen sulphide) to form sulfuric acid (H 2 SO 4 ). Sulfuric acid then reacts with calcium carbonate, causing increased erosion in limestone formations. The chain of reactions is:
This reaction chain forms gypsum.
Morphology
Landscape karstification can produce various large or small scale features both on the surface and below. On exposed surfaces, small features may include flute solutions (or rillenkarren), runnels, clints and grikes, collectively called karren or lapiez. The medium-sized surface features may include a sinkhole or cenote (vertical shaft), vertical axis, foibe (sinkhole shaped upside down), flow disappears, and reappears springs. Large-scale features may include limestone pavements, poljes, and karst valleys. Adult karst landscape, where more bedrock has been removed from the rest, can produce karst towers, or landscape of haystack/egg box. Below the surface, complex underground drainage systems (such as karst aquifers) and large caves and cave systems can form.
Erosion along limestone beaches, especially in the tropics, produces karst topography that includes a sharp makatea surface above the normal range of the sea, and undercuts that are largely the result of biological activity or bioerosion at or slightly above the mean sea level. Some of the most dramatic formations can be seen in Phangnga Bay in Thailand and in Halong Bay in Vietnam.
Calcium carbonate dissolved into water can precipitate out where water releases some dissolved carbon dioxide. Rivers emerging from springs can produce terraced tuffs, which consist of layers of calcite stored for long periods of time. In the cave, the various features collectively called speleothems are formed by precipitation of calcium carbonate and other dissolved minerals.
Hydrology
Farming in karst areas should take into account the lack of surface water. The soil may be quite fertile, and rainfall may be adequate, but rainwater moves quickly through the cracks to the ground, sometimes leaving the dry surface of the soil between the rain.
The karst fenster occurs when the underground stream appears to the surface between layers of rock, cascades some distance, and then disappears back down, often into a drain. The rivers in the karst area may disappear underground several times and reappear in different places, usually with different names (such as Ljubljanica, seven river names). An example of this is the Agie Popo River in Fremont County, Wyoming. On a site called "The Sinks" at Sinks Canyon State Park, the river flows into a cave in a formation known as Madison Limestone and then rises again 800 m ( 1 / 2 mi) down the gorge in a tranquil pool. Down is a unique type of seasonal lake found in Irish karst regions formed through the well water yearly from the underground water system.
Water supply from wells in karst topography may be unsafe, as water may have traveled unhindered from the drain hole in the cattle pasture, through the cave and into the well, through normal filtering occurring in porous aquifers. The karst formation is broad and therefore has a high permeability level, thereby reducing the chances of contaminants being filtered. Groundwater in the karst area is just as easily polluted as the flow of the surface. Sinkhole is often used as an agricultural or community waste disposal site. Overloaded or damaged septic tanks in the karst landscape can dispose of raw waste directly into underground channels.
Karst topography also poses difficulties for the human population. Sinkhole can develop gradually when the surface opening is enlarged, but progressive erosion is often not seen until the roof of the underground cave suddenly collapses. Such events have swallowed houses, cattle, cars, and agricultural machinery. In the United States, the collapse of such cave ruins swallows some of the National Corvette Museum's collection in Bowling Green, Kentucky in 2014.
Interstate karst
Interstate karst is a karstic landscape developed under insoluble rock cover. Usually this will involve a sandstone cover over the limestone layer that undergoes a solution. In the vast field of doline in Great Britain was developed in Mynydd Llangynidr in the Sandrstone High Plain which is above the Hidden Carbon Limestone.
Kegelkarst
Kegelkarst is a type of tropical karst field with many hills like cone, formed by cockpit, mogotes, and poljes and without a strong fluvial erosion process. This field is found in Cuba, Jamaica, Indonesia, Malaysia, Philippines, Puerto Rico, southern China, Myanmar, Thailand, Laos and Vietnam.
Pseudokarst
Pseudokarsts are similar in shape or appearance with karst features but are created by different mechanisms. Examples include lava caves and granite tors - for example, Labertouche Cave in Victoria, Australia - and features paleocollapse. Mud Cave is a pseudokarst example.
The famous karst area
The largest limestone karst in the world is the Australian Nullarbor Plain. Slovenia has the world's largest risk of exhaust pits, while the western Highland Rim in the eastern United States is at the second highest risk of karst sandhole.
Mexico hosts important constituents on the peninsula of Yucatán and Chiapas.
South China Karst in Guizhou, Guangxi, and Yunnan provinces is a UNESCO World Heritage Site.
Many terms relating to karst come from the Southern Slavic language, incorporating scientific vocabulary through initial research in the karst Alpine Balkans of Western Dinaric.
- AbÃÆ'®me, a vertical axis in karst that may be very deep and usually open into the underground line network
- Cenotes, deep drain holes, Mexican characteristics, resulting from the collapse of limestone rocks that confront the groundwater beneath it
- Foibe, inverted funnel sinkhole
- Scowle, an irregular karst landscape in the UK
- Turlough (turlach), a characteristic type of lake disappearing Irish karst
- Uvala, a collection of several smaller individual sinkholes that converge into a sinkhole compound. The word comes from the Southern Slavic language.
- Karren, the limestone ribbon that forms the surface
- Sidewalks of limestone, a landform consisting of flat surfaces, visible limestone scratches that resemble artificial pavements
- Polje (karst polje, karst field), a plain big plain karstic plain. The name "polje" comes from the Southern Slavic language.
- Doline, also drowned or drowned, is a covered depression that is drained underground in the karst area. The name "doline" comes from dolina , meaning "valley", and comes from the Southern Slavic language.
- Karst springs, springs emerging from karst, derived from the flow of water on the surface
- Ponor, also sink or sinkhole, where the surface flow enters the underground system. Derived from Slovenian
- Submerge streams, or ponornica in Southern Slavic languages ​​
- Karst fenster ("karst window"), a feature where the spring appears briefly, with water discharge then suddenly disappearing into the nearest exhaust.
See also
References
Further reading
- Ford, DC, Williams, P., Hydrogeology and Geomorphology of Karst , John Wiley and Sons Ltd., 2007, ISBNÃ, 978-0-470-84996-5
- Jennings, J.N., Karst Geomorphology , 2nd ed., Blackwell, 1985, ISBNÃ, 0-631-14032-8
- Palmer, A.N., Geological Cave , 2nd Print, Cave Book, 2009, ISBN 978-0-939748-66-2
- Sweeting, M.M., Landform Karst , Macmillan, 1973, ISBNÃ, 0-231-03623-X
- van Beynen, P. (Ed.), Karst Management , Springer, 2011, ISBN 978-94-007-1206-5
- Vermeulen, JJ, Whitten, T., "Biodiversity and Cultural Property in the Management of Limestone Resources in East Asia: Lessons from East Asia", The World Bank, 1999, ISBN 978-0-821345-08-5
External links
- Speleogenesis Network, communication platform for physical speleology and karst science research
- Speleogenesis and Karst Aquifers - glossary of major Karst related terms
- Acta Carsologica - research papers and reviews in all karst related fields
- Citizen CDK Karst - Karst Citizen, non-profit non-profit organization dedicated to protect Karst Puerto Rico (available on English-language sites)
- Virtual Cave Pages in karst landform
- Karst Information Portal - an open access digital library connecting scientists, managers, and explorers
Source of the article : Wikipedia
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