- Karst topography
Karst topography is a landscape shaped by the dissolution of a layer or layers of soluble
bedrock, usually carbonate rocksuch as limestoneor dolomite. Due to subterranean drainage, there may be very limited surface water, even to the absence of all rivers and lakes. Many karst regions display distinctive surface features, with sinkholes or dolines being the most common. However, distinctive karst surface features may be completely absent where the soluble rock is mantled, such as by glacial debris, or confined by a superimposed non-soluble rock strata. Some karst regions include thousands of caves, even though evidence of caves that are big enough for human exploration is not a required characteristic of karst.
Terminology and etymology
Different terms for karst topography exist in other languages - for example, "yanrong" in Chinese and "
tsingy" in Malagasy (Jennings, Ch.1 p.1). The international community has settled on "karst", the German name for Kras, a region in Sloveniapartially extending into Italywhere it is called Carso and where the first scientific research of a karst topography was made. The name has a pre- Indo-Europeanorigin (from "karra" meaning "stone") and in antiquity it was called Carusardius in Latin. The Slovenian form "grast" is attested since 1177, and the Croatian "kras" since 1230.
Chemistry of karst landscapes
Karst landforms are generally the result of mildly
acidic water acting on soluble bedrocksuch as limestoneor dolostone. The carbonic acidthat causes these features is formed as rainpasses through the atmosphere picking up CO2, which dissolves in the water. Once the rain reaches the ground, it may pass through soilthat may provide further CO2 to form a weak carbonic acid solution: H2O + CO2 → H2CO3. Recent studies of sulfates in karst waters suggests sulfuric and hydrosulfuric acids may also play an important role in karst formation.
acidic water begins to dissolve the surface and any fractures or bedding planes in the limestone bedrock. Over time these fractures enlarge as the bedrock continues to dissolve. Openings in the rock increase in size, and an underground drainage system begins to develop, allowing more water to pass through and accelerating the formation of underground karst features.
Somewhat less common than this limestone karst is
gypsumkarst, where the solubility of the mineral gypsum provides many similar structures to the dissolution and redeposition of calcium carbonate.
The karstification of a landscape may result in a variety of large or small scale features both on the surface and beneath. On exposed surfaces, small features may include flutes, runnels, clints and grikes, collectively called karren or lapiez. Medium-sized surface features may include
sinkholes or " cenote"s (closed basins), vertical shafts, foibe(inverted funnel shaped sinkholes), disappearing streams, and reappearing springs. Large-scale features may include limestone pavements, poljes and blind valleys. Mature karst landscapes, where more bedrock has been removed than remains, may result in karst towers or haystack/eggbox landscapes. Beneath the surface, complex underground drainage systems (such as karst aquifers) and extensive caves and cavern systems may form.
Erosion along limestone shores, notably in the
tropics, produces karst topography that includes a sharp "makatea" surface above the normal reach of the sea and undercuts that are mostly the result of biological activity or bioerosionat or a little above mean sea level. Some of the most dramatic of these formations can be seen in Thailand's Phangnga Bayand Halong Bayin Vietnam.
Calcium carbonate dissolved into water may precipitate out where the water discharges some of its dissolved carbon dioxide. Rivers which emerge from springs may produce
tufaterraces, consisting of layers of calcite deposited over extended periods of time. In caves, a variety of features collectively called speleothemsare formed by deposition of calcium carbonate and other dissolved minerals.
A karst river may disappear underground a number of times and spring up again in different places, usually under a different name (like
Ljubljanica, the river of seven names).
An example of this is the Popo Agie River In Fremont County, Wyoming. Simply named The Sinks and Sinks Canyon State Park, The river flows into a cave in a formation known as the Madison Limestone and then rises again ½ mile down the canyon in a placid pool. When the river was dyed, it took two hours for the dye to reach the rise such a short distance away.
Water drainage and problems
Farming in karst areas must take into account the lack of surface water. The soils may be fertile enough, and rainfall may be adequate, but rainwater quickly moves through the crevices into the ground, sometimes leaving the surface soil parched between rains.
karst fensteris where an underground stream emerges onto the surface between layers of rock, cascades some feet, and then disappears back down, often into a sinkhole.
Water supplies from wells in karst topography may be unsafe, as the water may have run unimpeded from a
sinkholein a cattle pasture, through a cave and to the well, bypassing the normal filtering that occurs in a porous aquifer. Karst formations are cavernous and therefore have high rates of permeability, resulting in reduced opportunity for contaminants to be filtered out. Groundwaterin karst areas is just as easily polluted as surface streams. Sinkholes have often been used as farmstead or community trash dumps. Overloaded or malfunctioning septic tanks in karst landscapes may dump raw sewage directly into underground channels.
The karst topography itself also poses some difficulties for human inhabitants. Sinkholes can develop gradually as surface openings enlarge, but quite often progressive
erosionis unseen and the roof of an underground cavern suddenly collapses. Such events have swallowed homes, cattle, cars, and farm machinery.
Driftless Area National Wildlife Refugein Iowaprotects " Discus macclintocki", a species of ice age snailsurviving in air chilled by flowing over buried karst ice formations.
"Pseudokarst" refers to landscape features that are similar in form or appearance to karst features, but are created by different mechanisms. Examples include
lavacaves and granitetors (for example Labertouche Cavein Victoria, Australia), and paleocollapsefeatures.
List of notable karst areas
Anjajavy Forest, western Madagascar
Ankarana Reserve, Madagascar
Madagascar dry deciduous forests, western Madagascar
Tsingy de Bemaraha Strict Nature Reserve, Madagascar
* Area around
Guilinand Yangshuoin Guangxi Zhuang Autonomous Region, China
Gui Zhou Province, China(The biggest karst cave in the world)
ZhangjiajieNational Forest park, forming part of the Wulingyuanscenic area (a UNESCO World Heritage Site), Zhangjiajie Prefecture, Hunan, China
The Stone Forestcalled the South China Karstby UNESCO (Yunnan Province, China)
Ofraregion, West Bank
Akiyoshi plateau, Japan
El Nido, Palawan, Philippines
Coron, Palawan, Philippines
Sagada, Mountain Province, Philippines
Chocolate Hills, Bohol, Philippines
Negrosand Gigante Islands, Negros Oriental, Philippines
Vang Vieng, Laos
Gunung Mulu National Park, Malaysia
Kinta Valley, Perak, Malaysia
* Krabi region,
Phangnga BayArea, Southern Thailand
Kenting National Park, Taiwan
Taseli plateau, Turkey
Halong Bay, Vietnam
Phong Nha-Ke Bang, Vietnam
Tam Coc - Bich Dongin Ninh Binh Province, Vietnam
Herzegovinaregion of Bosnia-Herzegovinaand Montenegro
* The regions of
Dalmatia(including Zagora), Lika, Gorski kotar, Kvarnerand the islands in Croatia
* The Central Rhodope karst in
Bulgaria( Trigrad Gorgeand caves), the DevnyaValley (karst springs)
Apuseni Mountains, Romania
Slovak Paradise, Slovak Karstand Muránska planina, Slovakia
* The region of Mecsek Mountains in Hungary
* The region of
Inner Carniolain Slovenia
Kras, a plateau in southwestern Sloveniaand northeastern Italy
Murge, in Apuliaand Basilicata, southern Italy
* The Cadí mountain range,
GarrafNatural Park area, Catalonia
Picos de Europaand Basque mountains, northern Spain
Ciudad Encantadain the Cuenca province ( Castilla-La Mancha, Spain)
Torcal de Antequeranature preserve, southern Spain
White Peakof the Peak District, UK, around Matlock, Castleton, and Thor's Cave
Yorkshire Dales(including Malham Cove), England
The Burren(Co. Clare, Ireland)
Assynt, southeast Skyeand near Kentallenin Scotland
* The limestone region of the Southern
Brecon Beacons National Park, Wales
Hönnetal at Balve, Germany
Swabian Albregion in the federal state of Baden-Wuerttembergin southern Germany
* The Ares de l'
Anie, in the southernmost part of Barétousvalley, southwest France
* The eastern part of the
Northern Limestone Alpsin the provinces of Salzburg, Upper Austria, Styriaand Lower Austriaforming huge limestone plateaus such as Steinernes Meer, Hagengebirge, Tennengebirge, Dachstein, Totes Gebirge and Hochschwab
* The area around
Graz, Styria, Austria
Caussesof the southern Massif Central, France.
Tuhala karst area, Estonia
* The Nahanni region in the
Monkman Provincial Parkin the Northern Rockies
Niagara Escarpment, Ontario
Wood Buffalo National Parkin Albertaand the Northwest Territories
* Marble Canyon,
Kosciusko Island, southeast Alaska
* The Mitchell Plain and uplands of southern
* The Great Valley of Appalachia (
Huntsville, Alabamato northeast Pennsylvania)
* The Shenandoah Valley of Virginia
Driftless Areaof southwest Wisconsin, southeast Minnesota, northeast Iowaand northwest Illinois, left unglaciated by all three phases of the Wisconsin Stage
Mammoth Cavearea and Bluegrass regionof Kentucky
Illinois Caverns State Natural Areaand Illinois Sinkhole Plain in Monroe County, Illinois
Ozark Plateauof Missouriand Arkansas
* The Kamas Ranch and Alabaster Cavern area of
* The Cumberland Plateau in Middle
* The Grassy Cove Karst Area,
Tennessee, "a registered National Natural Landmark"
Carlsbad Caverns National Parkof New Mexico
* The Hill Country of
Texasand its northern extensions, including the Palo Pinto Mountains
Presque Isle Countynear and around Rogers Cityin northern Michigan
* The campus of the
University of California, Santa Cruz
* The Germany Valley Karst Area,
West Virginia, "a registered National Natural Landmark"
Swago Karst Area, West Virginia, "a registered National Natural Landmark"
Karst forestin Puerto Rico
Limestoneeastern foothills of Maya Mountainsincluding parts of the Cockscomb Basin Wildlife Sanctuary
* Los Haitises National Park,
* Cockpit Country, a region in Jamaica
Limestonemountains of northwestern Puerto Rico
Mogotes in Viñales Valley, Cuba
Cenotes of the YucatanPeninsula, Mexico
* The Sótanos of the
Sierra Gorda, Querétaro, Mexico
Madre de Dios Islandand Guarello Island(the world's southernmost limestonemine), Magallanes, Chile
Cutta Cutta Caves National Park& Kintore Caves Conservation Park, Karst limestone landscapes. Katherine, Northern Territory Australia
Leeuwin-Naturaliste National Park, southwest Western Australia(near Margaret River, Australia
Swan Coastal Plain, Perth, Western Australia, Australia
Naracoorte Caves National Park, South Australia, Australia
Jenolan Caves, New South Wales, Australia
Wombeyan Caves, New South Wales, Australia
Mole Creek Karst Conservation Area, Tasmania, Australia
Waitomo, Oparara regions of New Zealand
Nakanai Mountains, East New Britain, Papua New Guinea
List of notable pseudokarst areas
Arroyo Tapiadoin Anza-Borrego Desert State Park. Over two-dozen 'mud caves' can be found in this popular desert area east of San Diego, California.
*Jennings, J.N., "Karst Geomorphology", 2nd ed., Blackwell, 1985, ISBN 0631140328
*Sweeting, M.M., "Karst Landforms", Macmillan, 1973, ISBN 023103623X
* [http://www.speleogenesis.info/glossary/index.php Speleogenesis and Karst Aquifers] - a large glossary of Karst related terms.
* [http://carsologica.zrc-sazu.si Acta Carsologica] - research papers and reviews in all the fields related to karst.
* [http://sktfi.org SERA Karst Task Force] - A Karst Task Force dedicated to karst conservation and the clean-up of cave and karst features.
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