karst | geology | Britannica.com geology Moravian Karst Karst, terrain usually characterized by barren, rocky ground, caves , sinkholes , underground rivers , and the absence of surface streams and lakes . It results from the excavating effects of underground water on massive soluble limestone . The term originally applied to the Karst (or Kras) physiographic region , a limestone area northeast of the Gulf of Trieste in Slovenia , but has been extended to mean all areas with similar features. The caves of a karst landscape, Minerve, Hérault, France. Hugo Soria Karsts are found in widely scattered sections of the world, including the Causses of France; the Kwangsi area of China; the Yucatán Peninsula ; and the Middle West , Kentucky , and Florida in the United States . Conditions that promote karst development are well-jointed, dense limestone near the surface; a moderate to heavy rainfall ; and good groundwater circulation. Limestone ( calcium carbonate ) dissolves relatively easily in slightly acidic water, which occurs widely in nature. Rainwater percolates along both horizontal and vertical cracks, dissolving the limestone and carrying it away in solution.

Limestone pavements are produced by the removal of surface material, and the vertical fissures along joints are gradually widened and deepened, producing a grooved and jagged terrain. As it flows along cracks underground, the water continues to widen and deepen the cracks until they become cave systems or underground stream channels into which narrow vertical shafts may open. Most, but not all, of the principal cave areas of the world are areas of karsts. Features such as lapiés , natural bridges , and pepino hills are characteristic of karsts. cave: Karst topography If a cave becomes large enough and the top extends close enough to the surface, the top collapses. This produces depressions called sinkholes , which are among the most characteristic features of karst topography . Sinkholes commonly coalesce into much larger depressions called poljen , which are often flat-floored and covered with soil that is derived from the insoluble residues of the limestone. These poljen may be the only areas where cultivation can be carried on. However, limestones vary in solubility and in the proportion of insoluble components; hence the general surfaces of some karst areas can be farmed. Over broad areas, surface streams may be totally absent.

In fact, in some karst areas with heavy rainfall, all precipitation may disappear underground so completely that even water for domestic purposes may be difficult to find. In other places water may surface as large springs , flow as a stream across the surface, and then disappear again underground. Cross section of a cave. Encyclopædia Britannica, Inc. Geology and geomorphology -Limestone Pavement Conservation Limestone Pavement Conservation Geology and geomorphology Limestone pavement is a habitat with a high geological interest. Forms of limestone pavement can be found in many places in the world, especially in Alpine and Mediterranean areas, but these lack the distinctive surface patterning seen on British pavements. How limestone pavements form Limestone is a hard sedimentary rock consisting of calcium carbonate, formed by the deposition of plant and animal remains on the sea floor and is thus known as a calcareous rock. Limestones often contain the visible remains (fossils) of shells and corals. As limestone is a sedimentary rock, it is laid down in layers or ‘beds’ separated by ‘bedding planes’ which are caused by changes in deposition rates or content of material deposited.

Limestone pavements in England, Wales and Ireland are mainly formed on deep beds of Carboniferous limestones which were deposited about 350 million years ago. Those in Scotland can be found on more ancient Durness and Dalradian limestones. The formation of limestone pavements in the UK and Ireland began with the scouring of the limestone by kilometre thick glaciers during the last ice age. The weight of the ice removed the soil that lay over the limestone, and also fractured the limestone along existing horizontal surfaces of weakness known as bedding planes. Fractured rocks were stripped away leaving level platforms of limestone on which a thick layer of boulder clay (glacial till) was deposited as the glaciers retreated. Wind blown material was then deposited on top of the boulder clay. This external material is particularly important for soil formation, as limestone does not weather down into soil which would mean if there had been no glacial deposits, there would have been no soil development. From the flat limestone surfaces, the characteristic features of limestone pavement have been formed by water in the glacially deposited soil exploiting cracks and fissures in the rock such as bedding planes and joints (lines of weakness in the rock generally running at 90o to bedding planes).

Also deposited on the limestone platforms were erratic rocks, ranging in size from pebbles to huge boulders. These erratics, often rocks of a different type to the limestone, are one of the most visible indicators of glaciation on limestone pavements. Karst scenery Limestone pavement is a type of karst landform. Karst is the word for an area of soluble rock in which the landforms are of a solutional nature (i.e. they are caused by water dissolving the rock ) where drainage is usually underground through rock fissures rather than in surface streams. Karst, a term originating from a limestone region in the former Yugoslavia, is derived from the Slovenian word kras, meaning a bleak, waterless place. It is used to describe a landscape containing erosional features such as bare pavements, subterranean water systems, dry valleys, dolines which are small to medium sized closed depressions with no surface outlet for water (hundreds of metres in diameter and tens of metres deep); and poljes which are large depressions with diameters of 1km upwards and depths of over 50m or so.

It is the layer of debris left by the retreating glaciers and also by wind deposits that hold the key to the development of the characteristic limestone pavement landforms over the last 10,000 years. The karst landforms were formed by the gradual dissolving of the limestone by mildly acidic water seeping through the forest cover which had become established on the soil above the limestone platforms. If this glacial debris had not been in position, then the weathering processes that form limestone pavements could not have taken place. Clints and Grikes Due to the solubility of limestone, limestone pavements are associated with some very curious and unusual landforms. The most characteristic surface feature of limestone pavements is their division into blocks, called clints, bounded by deep vertical fissures known as grikes. Clints and grikes form under relatively deep cover of soil where water, carrying carbonic acid which is formed from dissolved carbon dioxide as well as organic acids from decaying vegetation, picks out vertical lines of weakness (joints) in the rock. These fissures widen over the years as the acidic water preferentially attacks the lines of weakness. Grikes take many thousands of years to form under the soil as the rate of solution is slow.

Over time, the soil on the top of the limestone platform began to disappear down the newly eroded grikes, and was gradually eroded from the tops of the platforms. Some of the material lost into the grikes was washed deep into the drainage systems of the limestone pavements through connecting fissures, leaving open grikes of a metre or more in depth. These erosional processes were increased when forest clearance and grazing was introduced by humans onto the buried pavements leading to a more rapid exposure of pavements. Runnels, Pits and Pans As well as clints and grikes, limestone pavements also have a number of characteristic surface formations. These are known as runnels, pits and pans and take different forms depending on the structure of the pavement on which they form. Runnels are gutter-like channels eroded out of the surface of the limestone which drain into grikes. The formation of runnels takes place under a shallow layer of soil. Runnels formed on steeply sloping limestone are usually close together and parallel, whereas runnels forming on gentle slopes take dendritic or branched forms which can be looked at as a miniature river system. Pits and pans are small scale solution features (i.e.

formed by water and acids dissolving the limestone) found on the tops of clints. Pits are deep and free draining into the subterranean limestone drainage system. Pans are shallow, have an impervious base and hold water. Both of these features also form under shallow soil cover. Some research indicates that the deeper features can be formed by humic acid from the root balls of trees resting against the limestone and dissolving it into the characteristic round bottomed features of pits and pans. When solution features on a limestone pavement are exposed due to soil loss, they become more weathered and ‘sharper’ in appearance. It is possible to differentiate newly exposed pavement from pavement which has been exposed for longer periods of time by looking at the sharpness Limestone pavement and Karren features The limestone features described above have specific scientific names and are known as ‘Karren’. Karren is a general term used to describe the total complex of superficial micro-solutional features of soluble rocks such as limestone and gypsum. Karren are particularly common on limestone pavements.

Karren forms include sharp-ridged grooves (rillenkarren) and their larger, elongated cousins (rinnenkarren), as well as rounded runnels formed beneath a soil cover (rundkarren). Other forms include the ubiquitous solutional hollows (kamenitzas), grikes (kluftkarren), clints (flachkarren), and horseshoe shaped stepped structures (trittkarren). References for this section Karst Topography and Sinkholes - Introduction Karst Topography and Sinkholes Physical Geography Karst Topography and Sinkholes A sinkhole measuring 150 feet wide and about 60 feet deep is shown June 12, 2002 a day after it opened near the Woodhill Apartments in Orlando, Florida. The sinkhole swallowed trees, pipelines and a section of sidewalk. Share By Matt Rosenberg Limestone, with its high calcium carbonate content, is easily dissolved in the acids produced by organic materials. About 10% of the earth's land (and 15% of the United States') surface consists of soluble limestone, which can be easily dissolved by the weak solution of carbonic acid found in underground water.

When limestone interacts with underground water, the water dissolves the limestone to form karst topography - an amalgamation of caves, underground channels, and a rough and bumpy ground surface. Karst topography is named for the Kras plateau region of eastern Italy and western Slovenia (Kras is Karst in German for "barren land"). The underground water of karst topography carves our impressive channels and caves that are susceptible to collapse from the surface. When enough limestone is eroded from underground, a sinkhole (also called a doline) may develop. Sinkholes are depressions that form when a portion of the lithosphere below is eroded away. continue reading below our video What are the Seven Wonders of the World Sinkholes can range in size from a few feet or meters to over 100 meters (300 feet) deep. They've been known to "swallow" cars, homes, businesses, and other structures. Sinkholes are common in Florida where they're often caused by the loss of groundwater from pumping. A sinkhole can even collapse through the roof of an underground cavern and form what's known as a collapse sinkhole, which can become a portal into a deep underground cavern.

While there are caverns located around the world, not all have been explored. Many still elude spelunkers as there is no opening to the cave from the earth's surface. Inside karst caves, one might find a wide range of speleothems - structures created by the deposition of slowly dripping calcium carbonate solutions. Dripstones provide the point where slowly dripping water turns into stalactites (those structures which hang from the ceilings of caverns), over thousands of years which drip onto the ground, slowly forming stalagmites. When stalactites and stalagmites meet, they forum cohesive columns of rock. Tourists flock to caverns where beautiful displays of stalactites, stalagmites, columns, and other stunning images of karst topography can be seen. Karst topography forms the world's longest cave system - the Mammoth Cave system of Kentucky is over 350 miles (560 km) long. Karst topography can also be found extensively in the Shan Plateau of China, Nullarbor Region of Australia, the Atlas Mountains of northern Africa, the Appalachian Mountains of the U.S., Belo Horizonte of Brazil, and the Carpathian Basin of Southern Europe.

Istria on the Internet - Geography & Geology - Karst afloramento; carste desnudo; carste exposto Romanian: Geologists call areas as bare karst because of the lack of vegetation. The bare karst has no rivers and no trees, but the flora is often very interesting. In most cases the bare karst is an artificial landscape, created by men. When the area gets riverless because of the low ground water table, a natural vegetation of forest is able to keep the former state. But as soon as this difficult situation is disturbed by mankind, an irreversible process starts which leads to the bare karst condition. Uncovered karst is found on islands and the immediate coastal area of Croatia. The hills and hillsides, now bare, were not always without vegetation. The present barrenness has been brought about by uncontrolled deforestation, the destruction of large areas of woodland to provide firewood, by the failure to replant trees, and the use of the treeless land as grazing for sheep and goats, and with all the consequences in the form of erosion that then followed. In Slovenia this process began more than 2000 years ago when the Romans started to use the enormous trees as masts for their ships.

From this point of view, the landscape is a remain of the wars against Carthage. It was also furthered by the Venetians who needed timber for their large fleets and the piles on which their city was built. Impressive Bare Karst areas in Europe include: The Triestine and Dinarian Karst in Italy and Slovenia, a single karst area divided into two parts by a political border. Burren in Ireland. Gottesackerplateau in Germany. Covered Karst This form of karst is found mainly in the coastal hinterland. Here the limestone rock has often been overlaid by the products of its own weathering and decomposition, and the karstic processes have then continued under the covering of humus. With sufficient rain, trees can grow - oak to about 2600 ft/ 800 m, then conifers to 5900 ft/1800 m, occasionally even higher. The entrance to ďż˝kocjanske Jame in Slovenia is located in a green dolina, a few hundred meters from ďż˝kocjan. An artificial tunnel at the bottom leads to the rear end of the cave.

Photo by © Jochen Duckeck In covered Karst, the vegetation covers the limestone. This has two important effects on the geology: The vegetation produces CO2 in the earth, which fastens the corrosion (dissolution) of limestone. The growth of caves is faster than in bare karst. On the other hand, the vegetation covers the limestone from the air, so there is much less erosion depending on weather, e.g., in covered karst no frost erosion appears. It is rather difficult to see if a certain area is a karst region when it is a covered Karst area. But if you know the signs, it is easy to recognize with the following questions: Are there caves? Are limestone or dolostone rocks visible, maybe exposted at the valley of a river? Are there many springs around? (This one is not a sure sign, but a good hint) Are there any rivers? Large areas without rivers are always some sort of Karst. You will often be able to spot riverless areas on a good map. Karst areas have a typical soil and vegetation. There is no ground water, so there will be no vegetation that depends on it.

The soil may regularily dry, so the vegetation will be used to this and be able to store some water. The soil is formed by the residuals of limestone dissolution, which are silt minerals. If there is any iron in the limestone, which is rather common, the soil will first have the colour of the iron oxide. But there are two different chemical reactions, depending on the temperature. In tropical and subtropical climates, the colour is red (terra rossa). In colder climates the colour is beige, a very typical yellowish brown. Doline - Dolina - Sink - Sinkhole - Cenote - Swallow Hole - Ponor A sinkhole or sink is a collapsed portion of bedrock above a void. Sinks may be a sheer vertical opening into a cave, or a shallow depression of many acres. In karst areas, a doline, sink or sinkhole is a closed depression draining underground. It can be cylindrical, conical, bowl-shaped or dish-shaped. The diameter ranges from a few to many hundreds of metres. The name doline comes from dolina, the Slovenian word for this very common feature. So this was originally a Slovenian slang word.

There are two different mechanisms for the forming of dolines: solution The corrosive solution of limestone by rainwater is very high in the area fo crack, allowing the water to run into the rock. This normally forms the bowlshaped type of dolines. The solution produces large amouts of clay (depending on the pureness of the limestone). This clay is water resistant and sometimes plugs the drainage, so little lakes of rain water can sometimes be found in dolines, a rare thing in waterless karst areas. collapse When a cave grows, there may be a point where the roof of a cavern is not stable enough. This results in (several) collapses that shape the roof like a dome. This process runs out, when the shape is able to hold the weight of overlying rocks. If the impact of this collapse reaches the surface, if the overlying layers are too thin. The ceiling collapses and a doline is formed. The doline is often a natural entrance to the cave. A ponor or swallow hole swallows the water of a stream or lake. SINKHOLES IN ISTRIA A vegetable patch between Trviďż˝ (Terviso) and Beram/ (Vermo). A soccer field near Vizinada.

A cenote is a partly water-filled, wall-sided doline. It is formed by the collapse of a cave which is (today, not necessarily at the time of the collapse) filled with water. This sort of doline is very common in Yucatan, Mďż˝xico, where a large cave system with many entrances is filled with water. The system was formed during the ice ages, when the surface of the sea was 100 m lower than today. When the glaciers melted and the sea level rose, the caves were filled with water. [Where are the cenote in Istria?] Dry Valley Valleys without a surface stream are very common in karst areas. They were formed in two ways: In times before the water table was too deep, the water drained on the surface. During the Ice Ages, the ground was frozen for several meters below the surface. Summer was too short to melt it this deep. But the frozen ground is water resistant, all cracks are filled with ice. So the drainage happened on the surface. Karren - Lapies - Limestone Pavements Karren are minor forms of karst due to solution of rock on the surface or underground.

The name Karren is German, originally it described this feature in the German and Austrian Alps, where exist large karst areas with Karren. Karren can be found on any kind of surface. They are formed when water runs down a slope dissolving the rock. Thus karren can be found on any soluble rock like limestone, dolomite or gypsum. Karren always show how the water flows, they run down the slope in the same path as the water. They get deeper and deeper. Sometimes only thin limestone walls, a few centimeter thick, remain. Very similar dissolution effects produce limestone pavements. They look very similar to karren, but normally they are formed along a crack in the limestone. In this case the water enters the crack and does not stay on the surface. The dissolution continues inside the crack, which gets wider and wider. Large limestone surfaces get cut into pavements. The number, position and direction of the clefts depends on the cracks of the limestone. Often the cracks, formed by tectonic forces, run in very few directions. Each direction shows one stage in the tectonic history of the limestone.

Limestone with two main directions of cracks, with an angel of about 90ďż˝ in between, makes the typical limestone pavement which looks like an enormous chess board. Karst Lake At first look, karst lakes look like any other lake, but there often is something special with such lakes. There may be no visible stream flowing in, or none flowing out of the lake. Sometimes there is neither. Those lakes tend to grow and shrink. The water level rises in spring, when the snow melts or after heavy rains. The level falls in dry periods. Some of those lakes disappear completely. Then they are called seasonal lakes, as they only exist in some seasons. The explanation of all this strange behavour are caves. The lake is fed by springs below the water level and emptied by swallow holes, also below the water level. Often the same cave works as spring and swallow hole, depending on the season. Another way to interpret this situation, is to say, the lake is a part of the ground water. The surface of the lake is the water table. When the water table in the hills around a depression rises above the ground of the depression, it is filled with water. When the ground water lowers, the lake dries up.

It is pretty difficult to decide, if a lake is true karst lake. The geological examination is very difficult and for some lakes the oppinions differ. Missing rivers in and out of the lake, are visible on a map, and give a first hint. Not all seasonal lakes are karst lakes but this is a second hint. And of course the existence of karst around the lake is necessary. Cerknisko Jezero in Slovenija is a Karst Lake. [Was ďż˝epiďż˝ lake/lago d'Arsa a karst lake?] Karst Spring A spring is a natural resurgence of groundwater, usually along a hillside or from a valley floor. Springs in karst areas differ from normal springs: they normally have a much higher production, as they are just the end of a waterfilled caves system. Also they are highly dependent on the weather. Every rain and, of course, the snow melting leads to increasing production. Karst springs regularly fall dry in dry periods in the summer! On the other hand, the water quality is often poor! Both effects have the same reason: the water flows rather fast through cave systems, there is not enough time for micro organisms to clean the water.

So karst springs are not a good source for water supply. An intermitting spring is a spring that falls dry several times or most of the year. In most cases this springs are situated above, but near to the groundwater table. As the groundwater table moves inside the rock over the year, it sometimes reaches the spring and the water starts to flow. As very wet years often resulted in crop failure, the production of some wells were counted as a bad omen. The Hungerbrunnen (famine well) in Germany is an example. [Where are the karst springs in Istria?] Losing Stream A losing stream is one with a bed, which allows water to flow directly into the groundwater system. A very famous losing stream in Germany is the Danube. The Danube-spring is located in the Schwarzwald (Black Forest), from where the Danube flows to the east. Near Immendingen and again near Fridingen swallow holes in the bed of the river make the river loose some water. In dry years, the Danube gets completely dry and is reactivated several kilometers away by some tributaries. The water reappears in the Aachtopf.

Natural Bridge or Tunnel This term refers to a natural arch, bridge or tunnel which is a void beneath still standing bedrock, usually of short extent, and allowing human passage from one end to the other, at least part of the time. A natural arch is an arch of rock formed by erosion (weathering). A natural bridge a bridge of rock spanning a ravine or valley and formed by erosion. A tunnel is a nearly horizontal cave open at both ends, fairly straight and uniform in cross-section. Veliki naravni most, a natural bridge in the Rakov National Park near Postojna, Slovenia. Photo by © Jochen Duckeck A natural bridge is somewhat shorter than a tunnel. There are two different types of natural bridges/arches depending on their formation. The following explanation focuses on the second type of natural bridges: Natural bridges and arches - like in Arches NP in USA - are formed by multiple erosive processes, like fluvial erosion (flowing water, rivers), frost erosion and wind erosion. They may be formed in not soluble rocks like basalt or sandstone, but also in limestone. Natural bridges and tunnels in karst areas are the ruins of caves. In large cave systems collapses are very common.

Very often they result in domes that are optimal to stand the pressure of the overlaying rocks. Sometimes the caves are large and very near to the surface, so the ceilling gets too thin and collapses. As erosion goes on, the collapsed rooms are widened to small valley with a river, the former subterranean river. The valleys grow larger, the connecting cave remains get shorter. Sometimes the remaining caves are short enough, to see the other end and the next valley. This may be the time to call them tunnel. Examples of Natural Bridges: Veliki naravni most (photograph above, right) in Rakov ďż˝kocjan Nature Reserve near Postojna, Slovenia. Polje (Karstic fields) A polje is a large closed depression draining underground, with a flat floor across which there may be an intermittent or perennial stream. The polje may be liable to flood and become a lake, and its floor makes a sharp break with parts of surrounding slopes. Polje is the Slovenian word for "field", which means the flat and very fertile ground of the valleys in Slovenia.

In the area around Postojna many valleys show the same characteristics: The end of the Rakov Polje in Rakov National Park near Postonja, Slovenia. The river flows down the narrow valley and enters a cave. It is possible to visit the first part of the cave, but the rest is not even explored by speleologists. Some divers explored only a short part of it, then the river became too deep. Photograph © Jochen Duckeck. The valleys are rather small, a few hundred meters wide and up to one or two kilometers long. The sides of the valleys are rather steep. Most valleys have a stream flowing from one end to the other. The stream enters the valley in a karst spring, often the entrance to a cave. The stream leaves the valley in a Ponor or the entrance to a cave. And last but not least: the valley has a flat and very fertile ground. This typical form of a Polje is easy to explain, when the way they were formed is clear. The karst area is drained underground by caves. If the caves are rather near to the surface and rather big too, sometimes the roof collapses and forms a dolina.

The stream tht flows through the cave now flows through the Doline and [data missing]. Typical features of poljes are their disappearing rivers. These usually emerge at the edge of a polje and after flowing for some distance disappear into the ground again. After heavy rain, normally occurring at the end of winter, the cavities in the ground may not be able to absorb all the water immediately. This then forms a lake, which may end by covering the whole area of the polje. The peasants therefore always have their houses at the edges of a polje, and if there is a heavy early rainfall in autumn must make haste to get the harvest in before it is covered by the rising flood-water. The passing summer tourist may be surprised to see small boats lying about among dry cornfields; but these serve a useful purpose when the poljes quickly turn into lakes after heavy rain. A peculiarity of karstic country is the absence of rivers of any length.

Along the whole length of the Croatian Adriatic coast only a few above-ground rivers of any size reach the sea - the Dragonja, Mirna and Raďż˝a in Istria, the Krka and ďż˝ikola at ďż˝ibenik, the Cetina at Omi and the Neretva in the Opuzen delta. The water which seeps into the ground re-emerges at the foot of the hills in the form of large karstic springs . In the extensive karstic region large numbers of caves have been formed by the erosion of water-soluble rock. The total number of caves can only be estimated, but is certainly over 10,000. In Slovenia alone - where the exploration of caves has been most actively pursued - there are more than 3,500, mostly in Triassic, Jurassic and Cretaceous limestones. Tower Karst - Cockpit Karst - Cone Karst English: Carst (n) de turnuri carst (n) conic This category has a spectacular variety of karst landscape, dominated by steep or vertical sided limestone towers (karst towers) or cones.

The towers originate as residual cones and are then steepened by water table undercutting from surrounding alluviated plains. Tower karst, cone karst and cockpit karst are different but rather similar forms of this kind of landscape. There are two different explanations for this kind of landscape, both explaining a certain aspect of the geology. In reality, it seems to be a combination of both: Tower Karst is typically interpreted as a karst area in a very late stage of development. To explain this we first need a sort of chronology of karst development: Limestone reaches the surface and gets subject to weathering. Ground water starts with the solution of limestone and forms first caves. A lower drainage system around the limestone area is necessary for the secons stage: the rivers and lakes leave the surface, drainage of the whole area is underground. This is the "typical" stage of a karst area, which we know well from moderate climate zones. The limestone caves get bigger and bigger and start to collapse. Cave systems are marked at the surface by daisy chains of dolines. Dolines merge and form poljes. The cave systems are more or less collapsed.

The former poljes grew and grew until they are all connected and again form a net of subaerial valles draining the area. The former limestone plateau is cut into isolated limestone islands. The formation of the towers is a combination of tectonic uplift and tropical karst erosion. Tectonic uplift matched by karst erosion increases tower heights, as the solution is bigger in the valleys. If uplift is too slow, the towers are dissoluted and shrink, if it exceeds erosional surface lowering, the towers are raised to hillside locations and the landscape is rejuvenated to form a new generation of dolines and cone karst. Cone and tower karst exist only in sub tropic and tropic climate zones. Both typically exist in in areas with tectonic uplift. In many areas the towers are full of inactive caves at (multiple) higher levels, and with active caves through their bases. There may be alluvial plains between the towers and flat-floored depressions within them. Cockpit karst is the beginning of the development. After cave systems developed, grew and collapsed, the former caves form huge valleys and the limestone inbetween remains as hills.

Cone karst is the more common and less spectacular form of this landscapes with steep limestone hills, residual cones, typically covered by rain forest. Tower karst is the spectacular form with 30-300m high towers with vertical or overhanging sides. The walls are typically bare rock, as the walls are too steep for vegetation. Tower karst occurs throughout southeast Asia. By far the most extensive and best developed tower karst is in the Guangxi province of southern China. This is the ultimate development of tower karst, in which the residual hills have very steep to overhanging slopes. Other famous areas of tower karst are Vietnam, Thailand and Malaysia. Cone karst occurs in Cuba, Madagaskar and Puerto Rico. Very common is submerged tower karst on the coast of Thailand and in the Chinese Sea. The towers form steep limestone islands in the sea, sometimes with donlines inside that form salt water lakes with steep walls. This spectacular landscape was used as location for many movies. Most famous examples are (per IMDB): James Bond movies - The Beach with Leonardo DiCaprio - Karst Caves A cave is an airfilled underground void, large enough to be examined in some way by man.

While there are caves in other kinds of rock besides limestone, dolomite and gypsum, they do not have karst features and therefore are not karstic caves. [expand] Typical features of karst areas are: No water on the surface, water oozes away and flows in subterranean rivers. Large springs, often with rapidly changing amout of water, depending on the weather. Dolines or sinkholes. Karst lakes which have no connection to rivers on the surface. Dry valleys which were formed when the rivers were still on the surface, before the karst developed. Speleothems - Karstic Cave Formations [expand] The term dripstone is applied to a variety of different formations: Water dripping from the roof of a cavern may form calcium "icicles" or stalactites, or it may build up stalagmites on the floor of the cavern. When stalactites hanging from the roof join up with stalagmites growing upward from the floor and then increase in thickness they form columns known as stalagnates. Another type of formation which creates a particularly striking effect in illuminated caverns consists of the sinter curtains formed by water trickling from an overhanging rock face. This can produce canopy-like formations.

like those to be seen in the Postojna caves. The shape taken by the dripstone formations depends on a variety of factors, including the calcium content of the water, the amount of evaporation in the cavern and the direction of air movement. They are given their colouring by traces of metallic salts dissolved in the water. The formations in caves which have been open to the public for a century or more often lack the brilliance of colour found in more recently discovered caves. This is because in the past the caves were frequently illuminated by torches, bundles of burning straw or oil lamps, and soot deposits have dulled the colours. [insert a story or two about lights] Not infrequently the roof of an underground cavern will fall in, producing a depression like a bomb crater, known as a doline (sink, swallowhole), which may sometimes reach a diameter of as much as 1100 yd/1000 m. Adjoining dolines occasionally coalesce, forming what is known as an uvala. Stili larger depressions, sometimes covering many square miles and usually surrounded by hills, are known as poljes ("fields") .

Dolines usually provide good agricultural land, since fertile alluvial soil tends to accumulate in them. Poljes with a flat floor, making them particularly suitable for agricultural use, commonly acquire a cover of reddish clay-like soil (terra rossa) deposited by the percolating water. Examples of Karstic Areas and Caves The most famous complex of caves is the Postojna Caves (Postoinska Jama) in present-day Slovenia along the subterranean course of the River Pivka, with a number of connected caves, the Otoďż˝ka Jama, Crna Jama, Magdalenska Jama and Pivka Jama. After pursuing a course which has not yet been traced the Pivka reappears in the Planinska Jama, where it is joined by the River Rak, which has also followed an underground course, passing through the Zadnja Jama and Tkalca Jama (Weaver's Cave). To the east of Postojna is the beautiful Kirďż˝na Jama.

(See list of show caves in Slovenia at The Triestine and Dinarian Karst in Italy and Slovenia are, in fact, only one karst area - a large limestone plateau divided into two parts by the political border. The caves in Slovenija and the caves in Italy are connected. Around Trieste are the ďż˝kocjan Caves which belong to the Reka-Rimavo river system. These caves are traversed by the River Reka, with a number of other caves branching off them. Two notable caves in this region are Grotta Gigante and San Giovanni d'Antro. Southwest of Divaďż˝a are the Divaďż˝ka Jama and Vilenica Jama (Fairy Cave), still explored, and to the Southeast is the Dimnice Jama (Cave of Mist). In Croatian Istrian, the town of Pazin is situated on the rim of a gorge (the foiba of Pazin), into which the little River Pazinski Potok disappears and which is a typical karstic feature. This tremendous hole in the ground, Pazinska Jama, is said to have inspired Dante's vision of the entrance to the Inferno in his Divine Comedy .

Both the subterranean caverns and the castle in Pazin, now housing the Ethnographic Museum, are described by Jules Verne in his novel, Mathias Sandorf . A well-known karstic cave of recent discovery is Baredine Jama, near Poreďż˝. The most famous cave in Lower Carniola is the Taborska Jama (Tabor Cave), with the Ledenica Jama as an antechamber. An impressive example of karstic landscape can also be seen near Dubrovnik. In the neighbourhood of the little Moslem town of Trebinje is the Popovo Polje, more than 35 miles/60 km long, which fills up with water every September. *Shown on original text as Yugoslavia. Bibliography: Baedeker's Yugoslavia, translated from the German original, Prentice Hall Press, printed in Great Britain by Jarrold & Sons. Ltd. (Norwich, c. 1987), p. 99-101, 229, 262.

A Karst Primer - ~joellaws/ozark_caving/mss/karst.htm Show Caves of the World, Karst - Photographs of Sinkholes in Istria - Mirko Gabler. karst nedir, ne demek, karst anlamı - Sesli Sözlük A mountainous region in northeastern Italy and southwestern Slovenia A type of land formation, usually with many caves formed through the dissolving of limestone by underground drainage The shells are just 0.04 inch (one millimeter) long and were found on a karst formation where conditions are damp, but the snails that inhabit them have yet to be observed.

A geologic region characterized by layers of porous limestone containing sinkholes and underlain by caves and underground streams Topography with sinkholes, caves, and underground drainage that is formed in limestone, gypsum, or other rocks by dissolution A geologic formation of irregular limestone deposits with sinks, underground streams, and caverns A geological term for an irregular limestone region with sinks, underground streams, and caverns A terrain in which the landscape is shaped by the drainage characteristics due to the dissolving action of the underlying bedrock (usually limestone) Over thousands of years, various surface and subsurface features are developed -- sinkholes, streams, springs, and caves to name a few The general term for landforms which includes caves, dolines (qv) and sculptured rock surfaces Such landforms are formed in areas where solution processes, rather than mechanical erosion processes, predominate Karst is most often seen in limestone Landform type with limestone bedrock and dominated by geomorphic features created from solution chemical weathering A type of land formation, usually with many caves caused by limestone being dissolved by underground drainage A landform comprised of sinkholes, sinking streams, zones of infiltration, underground passageways or watercourses, and spring resurgences, usually occurring in a soluble rock such as limestone

 or gypsum {i} region containing large deposits of limestone (Geology) An irregular topography that may form over partially dissolved limestone or dolomite; karst is characterized by sinkholes, caves, and underground drainage terrain with distinctive characteristics of relief and drainage resulting from the dissolution of soluble rocks such as limestone and dolomite A type of topography that is formed on limestone, gypsum, and other rocks, primarily by dissolution, and that is characterized by sinkholes, caves, and underground drainage From Glossary of Geology, 4th Edition, 1997, American Geological Institute an area of irregular limestone in which erosion has produced fissures, sinkholes, underground streams, and caverns An area possessing surface topography resulting from the underground solution of subsurface limestone or dolomite a type of terrane and/or hydrologic regime that is formed by dissolution of limestone, dolomite, gypsum, and other soluble rocks It is characterized by underground drainage and conduit-fed springs, and may include sinkholes, caves, and sinking streams A terrain or type of topography generally underlain by soluble rocks, such as limestone, gypsum, and dolomite, in which the topography is chiefly formed by dissolving the rock; karst is characterized by sinkholes, depressions

, caves, and underground drainage A type of topography that results from dissolution and collapse of carbonate rocks such as limestone and dolomite and characterized by closed depressions or sinkholes, caves, and underground drainage Water-soluble limestone, dolomite, and gypsum beds in which water has dissolved underground cavities, producing fissures, sinkholes, underground streams, and caverns Florida has numerous karst formations A topography formed over limestone, dolomite, or gypsum and characterized by sinkholes, caves, and underground drainage kg: Kilogram a set of landforms or a landscape formed by the solution of carbonate rocks Depressions or pits (sinkholes) and disappearing streams are characteristic of karst areas in temperate regions; below the surface, caves and caverns are common Karst is well developed in the Valley and Ridge physiographic province of Virginia Area of land lying over limestone and characterized by sinkholes, caves, and sinking streams A terrane, generally underlain by limestone or dolomite, in which the topography is formed chiefly by the dissolving of rock, and which may be characterized by sinkholes, sinking streams, closed depressions, subterranean drainage, and caves The occurrence of limestone as the first bedrock unit beneath the soil in which cav

ities form due to the solubility of limestone under certain conditions Surface characteristics include sinkholes and sinking streams A barren limestone region characterized by fissures, caves, and underground channels Landscape produced by the dissolution of limestones by by percolating ground waters and underground streams Named after the Karst region of the former Yugoslavia İlgili Terimler Natural heritage | Park Škocjanske jame Natural heritage Natural heritage The Škocjan Caves Regional Park is situated in the Classical Karst, which is also home of the bora wind as well as prosciutto and Teran wine.

The word Karst is capitalized here and we, the Karstians, are robust people; everyone is free to understand this in his or her own way. The Karst is the region between the northeastern shore of the Adriatic Sea and part of the continent where pioneering scientific exploration of Karst geography started. Many internationally recognized karstological terms originate in the Škocjan area, among others the term "doline" (Velika and Mala dolina). The Škocjan Caves and their surroundings were entered on UNESCO’s list of natural and cultural world heritage sites in 1986. In 1999, the Caves were entered on the Ramsar Directory of Wetlands of International Importance and in 2004, the Škocjan Caves Park was included in the world network of biosphere reserves called MAB - "Man and the Biosphere"; all of this was under the auspices of UNESCO. The Škocjan Caves are typical and the most characteristic Karst area of global importance and are considered to be one of the natural treasures of planet Earth. It is therefore necessary, proper and ethical to preserve them for our descendants.

The Škocjan Caves area ranks among the classic examples of contact Karst that has developed at the juncture of impermeable flysch and permeable limestone. The Škocjan system of natural and cultural heritage The regional park comprises a unique landscape that brings together a large number of natural valuable features or natural heritage in the form of Karst or other phenomena and interesting features. The regional park constitutes a typical “Karst architecture” with its system of caves, collapse dolines and individual natural monuments. The unique distribution of flora and fauna co-existing in an extremely small area proves that this is a highly diverse region in terms of both biotic and abiotic parameters and simultaneously a vulnerable one. With the assistance of local residents, the Park's employees pay attention mainly to the preservation of natural ecosystems and life in the genuine natural environment.

"Similarly to experiencing the Alpine idyll among peaks, the wilderness and huge vastness of collapse dolines, caves and walls never cease to overwhelm me; the gentleness, resilience and some kind of rebelliousness of maidenhair fern and Alpine auricula on one hand, and the mysteriousness, wildness and capriciousness of the Reka River and its tributaries on the other" (D. Rojšek). The power of nature that reminds man of his smallness and mortality. Here one can understand why it was believed that supernatural forces existed here. The Škocjan Caves have a highly multi-branched system of cave passages totalling 6.2 kilometres in length, the lowest point being 223 metres deep. They represent the largest and best-known natural phenomena in the region. The Caves have 11 speleological structures that are interconnected by means of the Reka River or collapse dolines. The shifting of the sinkholes in contact with the underground caves caused the formation of numerous collapsed dolines. Velika dolina and Mala dolina fascinate every visitor with their depth of 163 meters as well as great floral and faunal diversity.

The best view of both dolines, with their natural bridge and the cave that separate them, is from Miklov skedenj (Mikel barn), named after the local explorer Franc Cerkvenik – Mikl, a viewpoint 165 metres above the Reka River sinkhole. The Škocjan Caves are the beginning of the underground cave system with an enormous underground gorge, many lakes and waterfalls that are also parts of the local cultural heritage. At several points, the gorge is over 100 metres high. The Škocjan Caves hold what is probably Europe’s largest underground chamber, with the greatest cross-section of 12,000 square metres, thus giving an exceptional 2.2 million cubic metres of volume. Another characteristic of the Škocjan Caves is the range of different stalactite formations, the best-known of which are the Rimstone Pools (the Slovenia Post featured them on stamps) and some larger stalactites in the Great Hall, the most impressive being a giant stalagmite called the Giant.

The Reka River flows underground for almost 40 kilometres and resurfaces at the springs of the Timava River in the Gulf of Trieste (Italy). Much remains to be discovered and studied about the river's underground section. Before entering the Škocjan Caves, the Reka River created a 2.5-kilometre long surface gorge carved into the limestone rock, on the banks of which there once stood the Školj Castle. Nowadays, the banks are full of interesting botanical and faunal features. Natural heritage in the protected area is protected by law. In 1996, the following natural phenomena were declared to be natural monuments due to their outstanding natural and aesthetic value: Mala dolina and Velika dolina all the way to the collapse doline edge; Okroglica abyss; Walls and banks of the Reka River valley in the radius of 150 metres before the entry into the Mahorčič Cave; Underground caves in the area of the Park: Škocjan Caves (Škocjan cave system); Jama na Prevali II.

(Fly Cave); Mala jama na Prevali (Skeletna Cave); Škrlica Cave; The stalactite in the Lipje Caves near Divača. Škocjan Caves Regional Park Act (Official Gazette of the Republic of Slovenia, No 57/96). Prepared by: Tomaž Zorman. Sources and literature: Daniel Rojšek. Geografsko vrednotenje naravne dediščine na primeru Škocjanskega jamskega spleta z okolico in varstvo okolja. FF, Odd. Za geografijo. Magistrska naloga. Ljubljana 1994. Katalin Bolner Takacs. The caves of the Aggtelek karst. Aggtelek national park. Josvafo 1998. Maja Zagmajster et al. Poročilo o projektu Phare. Slovensko društvo za proučevanje in varstvo netopirjev. Ljubljana 2000. Tomaž Zorman.

Značilnosti Parka Škocjanske jame. Rokopis 1999. Tomaž Zorman. Turistična karta parka Škocjanske jame. Park Škocjanske jame. Škocjan1998. New Zealand's Geology | Hiking New Zealand New Zealand's Geology Oct 28th, 2015 Karst landscape The tablelands of the north-west South Island are a remnant of once extensive sea-level plain which over 45 million years ago stretched across New Zealand. In the last 14 million years the plain has been uplifted. It is made of marble and limestone. Limestone is mostly calcium carbonate, which came from the skeletons or shells of small sea animals which settled on the sea floor millions of years ago, and were compressed to form rock. It is often rich in fossils. Marble is limestone which has been metamorphosed by high temperature or pressure deep within earth's crust into a harder rock. Together limestone and marble constitute 5-10% of the earths surface. Karst is a term for a limestone landscape and comes from a region in Slovenia.

Under the eastern flank of the Mt Arthur Range, two very large cave systems have been discovered: Ellis Basin and Nettlebed. The entrance of the Nettlebed was discovered in 1969, and, over the years, 25 kilometres of passages have been mapped by speleologists. From the cave's highest opening (Blizzard Pot) to its lowest level is 889 m, making it New Zealand's deepest cave. Ellis basin cave system is longer, but not quite as deep as Nettlebed, though new sections are still being discovered. Mt Arthur is hard crystalline marble, and nowhere else in New Zealand is there such a complex series of ancient rocks eroded into such distinctively different landscapes. Ice ages carved out cirques high on Mt Arthur. Caves are formed when limestone/marble is dissolved by water. Water with dissolved CO2 is slightly acidic, more so when tannins leached from the forest are in it. It reacts with CaCO3 gradually dissolving it, and carving caves where streams flow through fissures in the rock.

Paparoas The Paparoa range – a backbone of rugged granite peaks and a lowland belt of limestone, carved by water into canyons, caves, and sinkholes. Sheltered by mountains and nurtured by a warm moist ocean current, this area has a subtropical microclimate with lush vegetation, giving the appearance of tropical rainforest. Stalagtites As water dissolves the limestone it becomes saturated with CaCO3. When the saturated solution drips from the roof, any evaporation of the water causes the CaCO3 to precipitate out of solution i.e. it becomes solid again. This can cause a stalagtite to form at the point the water drips from, or a stalagmite to form on the ground where the drop lands. A range of shapes can form by variations of this process: straws, pillars, curtains. Pancake Rocks Limestone, formed by sedimentation of shell debris, accumulated and compressed over millions of years, and then uplifted. The sea then forced its way under this geological formation, creating surge chambers and blowholes, that can explode with extraordinary power in the right weather conditions.

Also wind and waves have sculptured a range of towers, pinnacles and faces in the rock. Glaciers Glaciers are rivers of ice which are fed by snowfall at their head, and flow down valleys until they reach a lower altitude where it is warm enough to melt them. North west winds pick up moisture from the Tasman Sea and bring 15 metres of rain at 1500m, which delivers 45m of snow at 2500m. The accumulation of snow feeds the Fox and Franz Josef glaciers, two of the few in the world which come right down into rain forest. Fox and Franz are special because of the low level snouts and speed of movement. During 1965-67 the glaciers advanced 1-8m a day. The neve is the top part of the glacier, the huge collecting snow-field. New snow compresses the air out of old snow to form firn, which in turn is compressed further into blue ice. Gravity shifts the mass downward, and under the strain crevasses appear, which are the distinctive linear cracks that cross the glacier, especially where the incline increases, or there’s a corner.

Where the glacier is squeezed at the narrowest and steepest part of its descent you will see the ice-fall, a mangled bunch-up of crevasses and seracs, isolated pinnacles of ice. Rock that has been crushed and dragged down by the glacier is called moraine. It collects at the sides of the glacier, on the surface, and at the terminal. Often, glaciers have terminal lakes, though this is not the case with the Fox and Franz glaciers, where you can the see the river gushing out from an ice-cave directly under the glacier. The ‘milkiness’ of the river is caused by glacial flour, which is a fine mass of silt and grit eroded by the glacier. Franz Josef Glacier was named after the emperor of Austria by the surveyor/geologist/explorer Julius von Haast. Haast named many mountains after his friends back home. The Maori called it Ka Roimata o Hinehukatere ‘the tears of Hinehukatere’. Fox Glacier has its own name, Te Moeka o Tuawe ‘the bed of Tuawe’.

There are glaciers on almost every continent of our planet, covering 11% of the land surface and locking up 90% of the above ground freshwater (85% is in Antarctica alone). Only Australia supports no permanent ice today. New Zealand has 3153 glaciers, except for 18 on Mt Ruapehu, all are scattered over the Southern Alps, comprising some 116 sq km of ice. Fiordland has been shaped by glaciers. This is evident from the shape of the valleys, which are U-shaped meaning they have steep walls and broad flat floors. In contrast, valleys carved by rivers are described as V-shaped. The glaciers in Fiordland were carving these valleys during the last ice age, 20,000 years ago, when the sea level was 100 m lower due to much of the water being locked up in ice. When the climate warmed, the glaciers receded to the mountain tops, leaving deep troughs which filled with water forming the lakes. Also sea levels rose flooding some valleys to form the fiords e.g. Milford Sound. Much of Fiordland is made of very old hard rocks (metamorphic e.g. gneiss; plutonic eg.

granite), hardened by pressure and heat beneath the earths crust then uplifted. Thus the steep valley walls cut by the glaciers have been slow to erode further and so remain near-vertical, giving the place its stunning topography. The Tasman is NZs largest glacier at 28 km long and up to 3 km wide. It once extended another 50km to the end of Lake Pukaki, which filled as the glacier receded. The Tasman glacier is up to 600m deep, and at the snout, still some 200m thick, the ice is 500 - 800 years old. It fell as snow long before Abel Tasman caught the first glimpse of the craggy skyline of the Southern Alps. Most people are rather disappointed at the ‘absence’ of the Tasman glacier. Instead of seeing a splendid vision of a crystal-white river, with ‘icebergs’ calving in a deep blue lake, the visitor sees a huge pile of rubble, finishing in a grubby lake and a thick dirty river. The glacier is there alright, and the rubble is only a metre deep in places, on top of 200m of ice.

All glaciers are huge grinding mechanisms, carrying large amounts of mountain debris to the plains. Some of this material is held suspended in the glacier. Because this glacier is receding, the debris is much more evident. The terminal lake of the Tasman Glacier was only a few sinkholes twenty years ago, and a fifty years ago you would have had to walk up from the road to get onto the glacier. The lake is likely to go on increasing in size quite rapidly. The Hooker and Mueller glaciers illustrate well glacial features such as lateral and terminal moraines, and the terminal lakes created by recession of glaciers. The Hooker river shows the cloudy grey colour imparted by glacial flour, the fine rock dust ground by the glacial movements. This flour at lower concentrations gives lake Pukaki its bright opaque turquoise colour. Greenstone Pounamu is a term applied to nephrite, known as jade in other countries, which is found in the Arahura and Wakatipu regions, and in many rivers and beaches between Jackson Bay and Martins Bay, and bowenite (which is a type of serpentine) found at its most significant site at Anita Bay in Milford Sound.

Bowenite is lighter in colour and called by the Maori ‘tangiwai’ meaning ‘tear water’. The exceptional hardness of greenstone made it highly desirable for weapons of war, and its beauty, desirable for ornaments. One account refers to greenstone as ‘kai kanohi’, ‘food for the eyes’. The Maori recognised several types of greenstone – kahurangi (light coloured), kawakawa (dark coloured), inanga (whitish, sharing the same name as whitebait) and tangiwai (transparent). Only in the South Island could the valued mineral be found, and the most abundant source was in the Arahura and Taramakau valleys. The Maori had regular trails and knowledge of the Haast Pass, Browning Pass, Harper Pass, Whitcombe Pass, and Lewis Pass. Greenstone is not always obvious in its natural state, for usually there is an outer rind of rock that could be anything from almost white to deeper browns. The Maori traditionally looked for greenstone when it was wet, after storms or an outgoing tide, when the greenstone was more easily distinguished.

Often some of the best greenstone pieces can be found on the coast, as they have survived the natural ‘grinding’ mechanisms of river and shingle. The milky-green inanga was particularly prized by the Maori. Hot Springs There are over fifty hot springs or seepages throughout the South Island, mainly associated with the Southern Alps and the Alpine Fault. This fault line is the consequence of the two tectonic plates that New Zealand sits astride, and literally moves mountains, such as the Red Hills; one part is still in South Westland, while the other has been slid up to Nelson. There are two commercial hot springs in the South Island, both on the Lewis Pass road, at Maruia Springs and Hanmer Springs. Natural hot pools contain microorganisms which are adapted to life at high temperatures – they have special heat stable proteins (enzymes) which can carry out the biochemical reactions on which life depends at temperatures which would destroy the proteins of most organisms. Some of the green slime in the pools is an algae called blue green algae (or cyanobacteria) which is the most simple primative type of algae i.e. one of the earliest types of plant which evolved.

It can photosynthesize but its cells don’t have nuclei, which is a characteristic of bacteria rather than algae. Southern lakes Lakes Wanaka, Hawea and Wakatipu all lie in hollows carved out by glaciers 20,000 years ago, and the surrounding hills shows the rounded forms sculptured by glaciers i.e. hillsides smoothed and contrasting with the jagged peaks above. Look out for roches moutonnees (sheep shaped rocks) isolated rounded hills with a smooth side where the ice rode up and a rougher steeper side where the passing ice plucked out pieces of rock. This area was opened up by gold prospectors in the 1860s, then settled by high country sheep farmers. More recently it has become a popular recreational area with trout fishing and boating on the lakes and rivers, tramping in the mountains, and skiing in winter. Numerous vineyards have sprung up in the last 20 years taking advantage of the hot dry summers, gentle autumn conditions, and plentiful irrigation water. Landslide The Green Lake landslide in Fiordland National Park, may be the largest of its type on earth. (Surpassed only by submarine and slow creeping slides).

It covers an area of 45 sq.km and the volume of earth that moved was 23 cubic km. The landslide occurred about 12,000 years ago and was probably due to an earthquake. A 9km segment of the Hunter mountains moved 2.5 km laterally and 700m downwards, creating a landslide dam 800m high. It formed an 11 km long lake which has since been filled in by glacial sediment, through which the Grebe river now flows. The debris formed the shelf which now holds Green lake and Island lake. Tussock basins On the shelf of landslide debris holding Green Lake and Island Lake are other depressions where tussock grows rather than beech forest. These may be old lake beds which have since silted up and infilled, where beech has not yet had time to establish. But there is another possible reason that beech forest does not grow there. These basins trap cold air forming a temperature inversion, so that although they are below the bushline, it is too cold for beech forest to grow. This is well illustrated by frosty nights spent camping at Green Lake – remember it is warmer camping under the beech trees.

Fossilised forest The fossil forest at Curio Bay is one of the most extensive and least disturbed in the world and the processes that brought the trees to this state and left them ‘beached’ on the remote and tranquil Catlins coast, were complex, and almost entirely violent. The fossilised forest has a history that goes back to Gondwanaland. This ancient super-continent comprised much of Antarctica, Australia, Africa, India and South America, and existed about 180 million years ago. Curio Bay forest then would have looked similar to New Zealand rainforest today - luxuriant ferns, and trees like kauri and matai. A few dinosaurs, but no birds, and much of modern New Zealand at that time was under water. Volcanic activity repeatedly buried the forest with ash, then new forest grew, and then another reburial. This happened at least four times, and then these sediments were buried deeply and silica minerals invaded the woody tree stumps and quite literally turned them to stone. Finally, the rock was brought to the surface, and eroded by the sea to expose the fossilised tree stumps - a remarkable transformation.

Schist tors Central Otago is a fragmented schist plateau, characterised by dramatic schist tors. The huge grinding process of weathering does its work unevenly, and some schist rocks are better at resisting than others - hence these columnar tors. Lichens have seized a hold on the rocks with some striking colours, in contrast to the brooding, almost sinister shapes of the tors. Scree The Central Southern Alps are made of a rock called greywacke, which weathers quickly. Its numerous cracks and weaknesses take up water, and when this freezes and expands, the rocks are fractured. The result is scree – a slow moving conveyor belt of rock debris. This is a unhospitable environment: unstable and subject to extreme temperatures. The plants which manage to survive on scree often have deep roots which reach down below the layer of mobile rocks into underlying moist sandy soil. The roots store reserves of energy so that if the surface parts of the plant are damaged, new parts can be grown. Colouration may be cryptic (blueish grey) to hide the plant from grazers, and surfaces waxy to prevent dessication.

Volcanic rock Mount Somers is an old volcanic rhyolite dome, quite distinctive from the greywacke that makes up most of South Canterbury. It is not an actual volcanoe (like Ruapehu) but magma squeezed up through a crack. The hard volcanic rock of Mt. Somers withstood glaciation, and has created an interesting topography with rock outcrops, waterfalls, and narrow gorges. Canterbury Plains The largest plains in NZ (300km x 100km). Geologists estimate that less than a million years ago the waters of the Pacific Ocean lapped against the base of the Southern Alps, but slowly, by glaciation, and by the action of the great braided rivers (Waimakariri, Rakaia, Rangitata), the mountains were eroded and the debris in the form of stones and gravel was carried down to the sea. These coarse gravels were deposited at the river mouths in great fan-like deposits, pushing simultaneously seawards and sidewards to eventually join up and form the Canterbury Plains. At the intersections of these deposits, smaller rivers such as the Ashley, Selwyn and Ashburton now flow.

Gravel deposits reach depths of up to a kilometre, soil is only 20-25cm, mostly made up of loess (wind blown soil). The Canterbury Plains was covered by totara dominated forest 2000 years ago, then huge fires devastated many trees. After the arrival of the Maori, much of the remaining forest of the Canterbury Plains was burnt, probably to allow bracken, the source of fern root, to establish itself. Braided rivers One the most distinctive habitats are braided rivers, huge channels of gravel that carve right across the Canterbury Plains and the MacKenzie Country, swirling with dust when the nor’wester blows. Plants and particularly birds have managed to establish themselves quite successfully in these arid and dynamic areas - over thirty bird species have been identified as using braided rivers, notably of course the wrybill and the black stilt. Banks Peninsula Made up of the remants of two basaltic volcanoes, Lyttleton and Akaroa which became extinct about 5.5 million years ago. Until the recent geological past, this area was an island, but was joined to the mainland by the gradual eastward movement of the Canterbury Plains.

Truman Beach The cliffs are sandstone with sea caves carved in at their bases. The beach is covered in rounded pebbles – all about the same size, but who sorted them so precisely? Particle size on beaches is determined by wave action. Turbulent conditions produce steep shingle beaches, which drain quickly and contain little organic matter, and are too harsh for living creatures. Smaller waves give moderately sloped sandy beaches whose smaller particles hold some water and often have shellfish buried beneath. Calm conditions create mud flats rich in organic matter (organic materials break down into small particles which settle out with fine mud particles) and good at holding water, where snails, crabs and mangroves can survive at the surface. Share it You may also like Getting around in New Zealand About travel distance miscalculations, low speed limits and the perks of being stuck behind a slow v... Happy Feet Make Happy Hikers Environmental Care Code Whilst hiking and travelling around New Zealand's it is important to follow a few simple steps to he... New Zealand Travel FAQs Arranging numerous trips for people from all over the world we have come across the same questions o...

Question: What term for an area of characteristic limestone scenery is named after a region of Slovenia?
Answer: KARST