Aggertal cave
| Aggertal cave
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| Location: | Oberbergisches Land , Germany | |
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Geographic location: |
50 ° 59 '37.5 " N , 7 ° 26' 54.2" E | |
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| Type: | Rock cave | |
| Discovery: | around 1773 | |
| Show cave since: | 1930 | |
| Lighting: | electric | |
| Overall length: | 1071 meters | |
| Length of the show cave area: |
270 meters | |
| Average annual number of visitors: | 4,800 (2010-2014) | |
| Current visitors: | 5,247 (2014) | |
| Website: | http://www.aggertalhoehle.de/ | |
The Aggertal Cave is a show cave in the Oberbergischer Kreis in North Rhine-Westphalia , Germany . It is located just under a kilometer west of the Ründeroth district, which belongs to Engelskirchen, near the Im Krümmel road (Landesstrasse 307), in a side valley of the Agger river , which has given it its current name.
General
The Aggertal Cave is located in the 47 hectare Altenberg nature reserve in the Walbachtal , which also includes several smaller caves. It was created by the erosion of the rock and is 1071 meters long, with a maximum height difference of 31 meters. Due to the slate lying above the cave , only a little carbonated water gets into it, which is why there are only a few small stalactites in the cave . However, fossils that are attributed to the Devonian are clearly visible.
The temperature in the cave is six to eight degrees Celsius all year round. A route of around 270 meters with a height difference of 10 meters is accessible on a guided tour. The Aggertal cave has been run by the Kluterthöhle e. V. scientifically supervised and researched.
history
Origin and special features
Geologically, the formation of today's Aggertal Cave can be attributed to the Middle Devonian period, when the territory of today's Bergisches Land was covered by sea water. The mountain range known today as the Rhenish Slate Mountains represented an extensive collection of elevations of the sea floor, which was often covered by coral reefs , stromatopores and limestone armor from marine animals. The formation and growth of the corals were favored by the humid tropical climate prevailing in this area at that time. The penetration of sea water into the folds of these elevations created cavities there in the Devonian period.
When, towards the end of the Devonian and the beginning of the Carboniferous - around 350 million years ago - the former parts of the sea floor were drained by folding and uplifting the mountains in the course of the Variscan Orogeny , the coral and limestone formed from the limestone Fossil remains as well as the mud and rubble of the former sea bed rock formations from Grauwacke . Over the course of millions of years, rainwater, which became carbonated through the absorption of the carbon dioxide contained in the air, seeped into the cavities of these rock layers and formed new cavities in them by washing out the lime. This karstification process resulted in a large number of caves in the area of the Rhenish Slate Mountains, including the Aggertal cave. In addition, the damming up of the water masses in the cavities up to the ceilings led to their washing out and collapse in places. Traces of these processes can be found today in several sinkholes or sinkholes , which connect the caves of the Rhenish Slate Mountains with the surface of the earth.
In contrast to the nearby Wiehler stalactite cave , layers of slate above the Aggertal cave essentially prevent the penetration of calcareous water into the cavities. The water that has seeped through has a relatively small volume and cannot absorb any lime because it only flows through layers of soil that are poor in lime. Due to this fact, the number of stalactites in the Aggertal cave is low. The variety of petrified marine fossils that have stuck in the rock layers and traces of erosion by water are clearly visible. A specialty among the fossil remains of the Aggertal cave are the numerous smaller aragonite crystal needles on the walls, which form large bundles in many places. They are remnants of corals made from magnesium-rich lime.
Discovery and Development
The exact time of the discovery of the Ründerother Cave by humans is not known. According to some old reports, it is said to have been entered for the first time in 1773. The possibly earliest written mention of the cave can be found in a file from the Bonn Higher Mining Authority from 1819, which is now only partially preserved. There is talk of a Feckelsberg cave discovered during mining . Since there are iron ore deposits in the mountains of the Oberbergisches Land , mining was quite widespread in this region in the 19th century. Whether the present-day Aggertal cave was meant by the Feckelsberger cave, for which the village of Feckelsberg, a few hundred meters away from the Aggertal cave, must have been named, cannot be clearly determined in view of the large number of smaller caves in its immediate vicinity.
Until the end of the 19th century, the cave remained largely unexplored and was very rarely entered by people, mainly because the only difficult access at the time was a deep sinkhole . It was not until 1890 that a 30-meter-long, horizontal access tunnel was drilled into the cave near this sinkhole . Since the area around the town of Ründeroth belonged to the Cologne industrialist Theodor Guilleaume at that time , the cave was known as the Guilleaume cave .
Extensive exploration of the Aggertal cave did not begin until the beginning of the 20th century. In 1910, the leading speleologist Benno Wolf drew the first, still quite simple, plan of the cave. The first show cave operation started in the early 1920s after the property had passed to the industrialist Otto Wolff . He had the now dilapidated tunnel renewed from 1890 and since then has occasionally organized tours and festivities in the cave, with the cave paths initially being lit with pitch torches.
From 1927 to 1930, the Ründeroth Beautification Association thoroughly prepared the cave for regular visitor traffic, after the landowner had given it to the association for guided tours free of lease. During this time, among other things, the access tunnel was rebuilt and electrical lighting was installed along the entire route. Most of the renovation and clean-up work was done on a voluntary basis, and the association was able to raise the necessary financial resources from private donations. The ceremonial opening of the show cave took place on October 12, 1930. Since then, regular public tours have been offered there.
Even if the Ründerother Cave was a popular research object for scientists from large parts of the Rhineland in the first few years after the renovation, it could not keep up with other well-known show caves in the Bergisches Land and the Sauerland in terms of the number of visitors - this was only around 3000 people annually . This did not change significantly when the community of Engelskirchen bought the area around the cave in 1933 and took over the show cave operations. This had to be interrupted in 1942 due to the events of World War II. In the spring of 1945, the abandoned cave was used as an air raid shelter by the people of Ründeroth for a few weeks - during this time around 50 people had settled there for permanent residence.
After the end of the war, the show cave operations could not be resumed, as the access tunnel, which had only been supported by wooden beams, had become unsafe. It was not until the summer of 1948 that the corridors were prepared for visitors again. On June 22, 1950, the cave was given its current name after a municipal council resolution, which should express the location of the cave in a side valley of the Agger . Two years later, the tunnel was provided with concrete walls that support it to this day.
From 1958 to 1960 the geologist Hans-Werner Holz carried out the first comprehensive investigations of the Aggertal cave and created a new cave plan. This indicated a corridor length of a total of 650 meters for the cave. In 1967 and 1981, annual meetings of the Association of German Cave and Karst Researchers took place in Ründeroth , with the focus on exploring the Aggertal cave. Another event in and around the cave was the celebrations for its 50th anniversary as a show cave in October 1980.
The latest investigations into the cave were carried out in the mid-1990s: After the municipality of Engelskirchen had entrusted the scientific supervision of the Aggertal cave to the Kluterthöhle working group in 1995, the latter carried out, among other things, a complete new measurement of the cave by 1996. A number of hitherto undiscovered paths were found, which increased the total explored length of the cave to 1071 meters. On the basis of this re-measurement, the association, which in addition to the Aggertal cave also researches the Klutert cave in the southern Ruhr area and the Wiehl stalactite cave in the Oberberg district, published a new cave plan in 1997.
Flora and fauna
Due to the fact that in the Aggertal cave there is an almost constant air temperature of around six to eight degrees Celsius with a humidity of over 80 percent and no daylight gets into the interior of the cave, only a few living beings adapted to these conditions can be found. The flora of the cave is essentially limited to the so-called lamp flora , which can only thrive there thanks to the electrical lighting. These include some types of moss , algae and ferns . These can be easily observed on the guide paths, as they form a green coating on the rock walls, especially near the artificial light sources. Spores of these comparatively undemanding plants mostly get into the cave with the seepage water, but are also brought in by visitors. In addition to the lamp flora, mushrooms can be found in the Aggertal cave that grow on damp areas of the wall.
The most important animal species in the Aggertal Cave are the bats , including the great mouse-eared bat , the fringed bat , the water bat and the small whiskered bat . In order to protect the bats that use the cave as winter quarters, it is closed to visitors from November to March. However, outside of the hibernation periods, bats can also be found very often in the Aggertal Cave.
Franz Lengersdorf was able to detect several other animal species in the Aggertal cave as early as the 1920s. These include certain two-winged insects that feed on the mushrooms, including the mushroom mosquito, and in the autumn and winter months also mosquitoes and sciarids . The latter serve as food for the cave spiders that also occur here . The water areas that form at higher groundwater level, revive springtails and some crustaceans, such as amphipods .
Worth seeing
From the entrance, the visitor first enters the anteroom of the cave via the access tunnel. Above this is the sinkhole, which was the only access until the tunnel was built. Today this opening is barred from the outside, and it is only partially visible from the inside.
The standard route is essentially a circular route with two almost parallel passages, the main passage and the coral passage . From the vestibule, visitors are first led into the southernmost part of the cave. There, at 18 meters, is the highest room in the Aggertal Cave, which owes this property to the partial collapse of the ceiling layers due to erosion. This exposed layers of slate that can be seen on the ceiling. In the southeasternmost room of the cave, the so-called water barrel , seepage water constantly flows through from above at one point, which contributes to the karstification process and thus to the expansion of the cavities. In the southern part of the cave, the few stalactites that exist in the leading area of the Aggertal cave can also be seen. A much larger stock of stalactites and stalagmites is located in the so-called treasure chamber , a northern passage of the cave, which is very difficult to access and therefore cannot be visited as part of a normal tour.
Limestone layers are visible on the walls of the main corridor to the west of the anteroom . Both here and in several other rooms along the route, they create bizarre shapes that have been washed out and that can evoke certain associations. With a little imagination, you can see a mountain spirit, a dragon's head, an elephant's foot, an eagle, a shark fin and also an old Fritz in the Aggertal cave .
To the north, the main corridor turns into a narrower corridor, which is known as the Partnach Gorge, as its two walls are somewhat reminiscent of the mountains and the gorge-like corridor shows similarities with the Partnach Gorge near Garmisch-Partenkirchen when viewed superficially . In the north-western corner of the route there is the room called the chapel . This name is based on both the dome-like ceiling of the room and the particularly good acoustics in this largest room in the Aggertal cave in terms of volume. For this reason, the chapel is occasionally used for musical events.
Not far from there, the narrowest part of the guide path runs parallel to the north-south corridor, which is called the Pastor's Walkway and is only around 30 centimeters wide in places. The name comes from an actual event: When the entrance tunnel was laid for the first time in 1890, the workers cleared the cave of clay and debris. They discovered a small corridor by chance. The news spread around the cave immediately. When a pastor who was visiting there heard of the discovery, he became curious and decided to visit the cave. However, since he was well fed, he got hopelessly stuck in this newfound passage. Only after much effort were the workers able to free the clergyman. Since then, the name Pastorengang has been used for this position . This part of the cave is an integral part of every guided tour these days.
The so-called coral passage leads from the pastor's passage back into the anteroom and towards the exit . Due to its comparatively low location, it is usually flooded to the ceiling in the winter months when the groundwater level in the cave is highest. The coral passage owes its name to a special diversity of the preserved coral remains, as the rock layers in this area have an almost horizontal shape and are therefore particularly easy to recognize individually. The base of these layers is an approximately three meter thick reef made of corals , tabulata and stromatopores , which is overlaid by limestone layers at the top, in which fossilized remains of mussels and brachiopods can be seen.
See also
supporting documents
Individual evidence
- ↑ Kluterthöhle e. V .: history of research; Retrieved on May 15, 2008 ( Memento of the original from August 28, 2009 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Dieter W. Zygowski: The Aggertal cave in Ründeroth. 1983, p. 18.
- ↑ Hans Maassen, Franz Lotze: The Aggertal cave in Ründeroth. 1953, p. 6.
- ↑ Dieter W. Zygowski: The Aggertal cave in Ründeroth. 1983, p. 20.
- ↑ Kluterthöhle e. V .: Winter census of bats; Retrieved on June 7, 2015 ( Memento of November 7, 2004 in the Internet Archive )
- ^ Franz Lengersdorf: The living animal world of the Ründerother cave. In: Bergische Heimat. No. 5, 1930, pp. 39-40.
- ↑ Dieter W. Zygowski: The Aggertal cave in Ründeroth. 1983, p. 27.
literature
- Hans-Werner wood: Geology of the caves of Ründeroth and Wiehl and their surroundings (Rheinisches Schiefergebirge) . In: Decheniana . No. 113 , 1960, ISSN 0366-872X , p. 1-38 .
- Hans Maassen, Franz Lotze : The Aggertal cave in Ründeroth (Oberbergischer Kreis). Your story and description . Tourist office of the climatic health resort Ründeroth, Ründeroth 1953.
- Dieter W. Zygowski : The Aggertal cave in Ründeroth . Traffic office of the community of Engelskirchen, Engelskirchen 1983.
Web links
- Official website of the Aggertal cave
- The Aggertal cave on the website of the working group Kluterthöhle eV
