donderdag 8 augustus 2013

Hungary, Caves of Aggtelek Karst and Slovak Karst

The variety of formations and the fact that they are concentrated in a restricted area means that the 712 caves currently identified make up a typical temperate-zone karstic system. Because they display an extremely rare combination of tropical and glacial climatic effects, they make it possible to study geological history over tens of millions of years.


The Caves of Aggtelek Karst and Slovak Karst lie over a total area of 55,800 ha and topographically comprise limestone plateaus dissected by deep river valleys. The territory is characterized by a fully developed karst landscape, of which dolines are the most typical surface landform. These have developed through solution and are, on average, 100 m wide and 20 m deep. Other surface phenomena include sinkholes and karren fields. This is the most extensively explored karst area in Europe, and a total of 712 caves have so far been identified. Many of the younger caves which have formed at the plateau edges, such as Krasnchorska and Gombasecka, occur on several levels and contain dripstone decorations. The most notable of these is the Baradla-Domica cave system which is 21 km long and connects Hungary with Slovakia. These caves are also noted for having the world's highest stalagmite, aragonite and sinter formations and an ice filled abyss, which considering the territory's height above sea level, is a unique phenomenon for central Europe. All these karst landforms are the result of long-term geomorphologic processes typical of this temperate climatic zone.
Hydrological conditions are characterized by a lack of surface streams, except between mountain basins, and the complex circulation of underground water. The flora is representative of both Pannonian and Carpathian elements. A unique biotope arises where two floral sectors overlap, and consequently many rare endemics can be found throughout the territory. Approximately 70% of the territory consists of deciduous woodland dominated by hornbeam and oak.
The fauna includes wolf, lynx, red deer, roe deer, wild boar, wild cat and badger. Nesting bird species include: rock bunting, black stork, corncrake, imperial eagle, dipper, Ural owl, saker falcon, short-toed eagle, honey buzzard. Of particular scientific interest are the cave and subterranean water fauna. Beetles and other insects are abundant. Cave worms are often found in sand and clay deposits whereas molluscs are associated with underground streams, and crustaceans occur including an endemic species of primitive carb. A total of 21 bat species have been identified in the Slovak Karst.
The caves themselves are of moderate extent and are not as long, deep or decorated as are other world caves. A significant aspect of the area is that it has undergone a great deal of fossilization and later exhumation of landscape features and subsurface groundwater routes. In other words, many karst features, after having formed, were buried by later sediment and then later reactivated or exhumed by erosional removal of the sediment. The resulting karst features contain a great deal of evidence pertaining to the geological history of the last several millions of years. The present karst landscape has been developing intermittently since the late Cretaceous period.
There is one sizeable settlement (Silica) and two hamlets within the Slovak protected area and two villages (Aggtelek and Josvaf with approximately 1,100 inhabitants) inside the Aggtelek National Park's boundaries. There is a serious pollution problem which is contaminating cave waters and threatening the park's ecosystem. This arises from the increased use of pesticides and fertilizers in the surrounding areas and from tourist's vehicles and nearby industry.

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