Speleology: This whole mountain region is rich in natural phenomena particular to chalky soil, grottoes and chasms of different shapes and sizes abound – in general, they are either vertical pits with wide mouths or narrow and dark chimneys. Tourists are hardly ever attracted by the grim and forbidding aspect of these holes. It is the potholer who decides to investigate. People who frequent the high Jura are familiar with these natural cavities known as «Ies Baumes», and this region has for long been methodically explored. More than 300 potholes are to be found in the part of the Jura Mountains belonging to the Canton of Vaud – most of them located in the «Vallee de JOUX». Hydro-geology: All the potholes in this part of the Jura have one common point: they drain and filter water through calcareous soil. This water feeds the basin of the «Vallee de JOUX» and, consequently, the underground Orbe. At the sides of the valley there are smaller grottoes, modest both in size and in beauty, which generate occasional streams. In any case, they cannot compare with the marvellous Vallorbe Grottoes which are fed by the waters of the whole region. The resurgence of the underground Orbe is one of the most important in the Swiss Jura and, thanks to the exploring divers, its beautiful cave-sculptures have been made accessible to everyone. Each year, the Jura Mountains experience abundant rain and snow falls. Rain water and thawed snow come into contact with the chalky soil which has special properties. The calcareous substance has been subject to erosion, soil movement etc and is very fragmented due to the action of the carbonic acid trapped in the chalky soil. Such water, charged with carbonic acid from the calcareous substances, permeates the chalky soil and an «aggressive» corrosive action takes place. The high Jura Mountains and plateaus show clear traces of this corrosion. Rain water is absorbed into the soil through thousands of small fissures and chasms. The water seeps downwards, joins under-ground channels and finally meets impermeable rock where it emerges in the form of «Vauclusienne» sources. Like the fountain of «Vaucluse» in France, the source of the Orbe emerges directly from chalky ground, at the foot of a rocky wall. The connection between the source of the Orbe and the lake water in the «Vallée de JOUX» was established already two centuries ago by De Saussure who described how the dam at the Bon Port «funnel» cracked. Muddy water infiltrated into the void and re-appeared the next day at the source. Since then, more accurate tests were carried out and it was established that the water took 22 hours to travel this distance under-ground. Today, the «funnels » are blocked but the source still enjoys an important supply of water from the lake. This is proved by the fact that the water temperature varies in accordance with temperature differences in the lakes. Where the Orbe makes its appearance above ground, another gallery is found. This was explored several times by the divers who established that the river course was once higher (as can be seen by the water level mark on the walls) and flowed out through the two small grottoes (Grottes des Fees) halfway up the valley's left slope. The water level in the grottoes fell as the river cut itself a deeper, faster course. One can imagine that long ago, a similar source existed in the «Grottes des Fees». The rock, fissured and rifted due to geological movement, was particularly suited to the erosive action of the underground river. In the galleries abandoned by the river, corrosion took hold once more – important deposits of calcium carbonate built up to form varied and interesting shapes. In the Jura Mountains, one litre of water can contain as much as 300 milligrams of calcium carbonate. In the grottoes, the river water as well as the water that trickles along the ceiling contains slightly over 150 milligrams per litre. However, this is sufficient. Evaporation, temperature increase or escaping carbonic gas will form tiny particles of calcium carbonate and in the course of thousands of years, these make up a considerable mass. The calcareous substance presents itself in varied shapes; covering the walls, stalactites hanging from the ceiling and stalagmites growing from the floor. The Vallorbe Grottoes possess some of the longest fistulas in Switzerland or in Europe (over 4 m). In several places, the thick walls show growths resulting from under-water deposits. The old water level is well marked by a swollen collar-like deposit. The Vallorbe Grottoes also harbour eccentric formations that defy the laws of gravity: needles growing in all directions, stalactites growing on existing stalactites etc. There are some very complicated shapes and many theories are put forward as to how they come into being. At river level, the blackened surface of the rocks is attributed to the organic matter in the lake water. Underground climate: As in all natural caverns, the climate in the Vallorbe grottoes is relatively stable throughout the year: around 10 deg. in summer and winter, humidity slightly less than 100%. This is shown by the amount of condensation on the clayey walls of the grotto. Ever since the grottoes were opened to visitors, the extra ventilation has tended to dry the atmosphere. Air and water mingle to produce a high percentage of carbonic gas in the atmosphere, about 0,3 % in the upper galleries and 0,4 % in the lower ones directly influenced by the river. This high rate of carbonic gas (about 10 times that of «normal» atmosphere) is common to most of the European grottoes and is neither harmful nor dangerous to the lungs. It is worth noting that such air is even beneficial to people suffering from asthma, bronchitis, etc – in some countries, the therapeutic properties of certain caves have been used successfully in treatment. Fauna: The animal life in the grottoes can be put into three categories. a) «Trogloxenes»: These are insects that find themselves in the grottoes by accident. They might be carried along by the river or might have fallen into a pothole etc. b) «Troglophiles»: is the name given to insects that find refuge in grottoes. They gene rally leave the grottoes at a given time, and can possibly reproduce. c) «Troglobies»: These are cave-dwellers proper, it being impossible for them to survive in any other surroundings. They can re-produce and will never come above ground. Such insects are often survivors from the ice-age and after having taken refuge in the grottoes, their organic system became so adapted to cave-life that they can no Ionger live in open air. The fauna in the grottoes is undoubtedly similar to that in the Grottes des Fees. As the Vallorbe grottoes have no other exit than the artificially-made one for tourism, organic matter cannot exist and thus, animal life is scarce. Near the underground river, carcases of little gnat-like insects may be seen. These are Phryganea (May-fly) which mature on the water surface. The larvae carried in by the river develop in the grottoes but the adult insect, unused to cave-life, dies then and there. History of discoveries: People were always curious about the source of the Orbe. Research work conducted by scientists De Saussure, Forel, Picard, etc., established the connection between the lake waters and the source. The first diver to explore was Pfund in 1893. At a depth of 10 meters, he saw that the tunnel continued. His diving gear forbade him to go down any deeper. After this, a long time later went by before a new attempt was made to penetrate into the underwater rock gallery. On July 1st, 1961, three divers entered the water. They reported that the entrance is like a tunnel at first, about 5 m wide and 2 to 3 m high with a downgrade of approx 45°. 20 m from the entrance, the tunnel flattens out and stays more or less Ievel but moving towards the right at an angle of 45 degrees. From there on, it is total darkness. The ceiling is now higher and the tunnel is 5 m wide by 6 m high. In September, the divers returned, this time armed with powerful torches. After penetrating 70 m into the gallery, they discovered a break in the wall that gave way to a lake which was immediately baptised «The lake of silence». In 1962, another attempt led them to discover, 140 meters from the entrance and still under water, a vast cave whose walls were invisible. On October 4th, 1964, the divers C. Giurumello and R. Schmid managed to find a crack in the walls of the Lake of Silence. From dry land, Mello could reconnoitre about 60 m while his comrade, hanging precariously onto a rock, took care of the equipment and held a guide rope. The discovery of the Vallorbe grottoes had just begun. Giurumello and Santandrea pursued their exploration together with other divers, their curiosity sharpened by the desire to discover the unknown. From then on, many expeditions were made. By 1966, the divers had already discovered many hundreds of meters of galleries, each as magnificent as the other. Remarkable pictures brought back by the divers evidenced their discoveries and quickened public interest in these mysterious explorations. The development project posed a big problem: how to preserve the grotto's innate beauty and at the same time provide easy access for visitors. These were a lot of hard work. These workers, many of them voluntary, should be paid a special tribute - their selfless efforts were rewarded by the official inauguration of the grottoes on April 6th, 1974. The site is open from April 1st to November 1st.
Questions:
1. In the region of Vallorbe, a layer of „grotto“ lime formed within a few million years.
1a. Name the different sediments included in that layer.
1b. How long approximately does this formation process take?
2. Name the three karst water zones.
3. Dripstones have different colors.
3a. What are these colors?
3b. What is the reason for this?
4. In which part of the grottoes are thousands of fistulas located? (ask the guide).
5. What is the name of the first diver?
6. Date of the official inauguration of the Vallorbe grottoes?
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Zusammenfassung in Deutsch:
Die Grotten von Vallorbe Die Grotten von Vallorbe beginnen bei der Stelle welche "Source de l'Orbe" genannt wird. Der Name des Flusses Orbe, welcher bei Vallorbe und Orbe vorbeifliesst, kommt vom vor-römischen oder indo-europäischen Ausdruck URBA welcher rund, kreis, kurve bedeutet.
Fragen:
1. In der Gegend von Vallorbe hat sich in wenigen Millionen Jahre eine Schicht von "Grottenkalk" gebildet.
1a. aus welchen Ablagerungen besteht diese?
1b. wie lange dauerte ungefähr dieser Prozess
2. Nenne die Bezeichnung der drei Karstwasserzonen
3. Tropfsteine haben verschiedene Farben:
3a. nenne diese Farben?
3b. nenne den Grund dazu.
4. In welchem Teil befinden sich tausende von Tropfsteinröhrchen? (frage den Führer)
5. Wie ist der Name vom ersten Taucher?
6. Wann wurden die Grotten offiziell eröffnet?
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Résumé en français:
La source de l'Orbe est la plus importante des sources vauclusiennes du Jura. Dans cette région les Grottes commencent. Le nom d'Orbe fut d'abord celui de la rivière qui passe à Vallorbe, puis à Orbe. Il s'apparente vraisemblablement à celui des innombrables cours d'eau dont les méandres et sinuosités leur ont valu d'être baptisés "ORB", d'une racine pré-latine et probablement indo-européenne signifiant cercle, rond, courbe. Tout naturellement, l'Orbe rivière devait donner son nom à la ville d'Orbe - l'URBA romaine.
Questions:
1. Dans la région de Vallorbe s'est créee pendant peu de millions d'années une couche de "calcaire de grottes"
1a. De quels matériaux est elle composée
1b. Quelle était environ la durée de ce procédé?
2. Quelles sont les noms des trois zones du karst
3. Les concrétions (stalactites – stalagmites) ont différentes couleurs
3a. Quelles sont ces couleurs?
3b. Quelles sont les raisons de ces couleurs?
4. Dans quelle partie des grottes se trouvent des milliers de fistules? (demande au guide)
5. Quel est le nom du premier plongeur?
6. Quand ont été ouvertes officiellement les grottes de Vallorbe?
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Attention: Groundspeak a changé les règles des Earthcache en juin 2019, et dorénavant une photo est obligatoire sur chacun de mes Earthcache !
https://www.geocaching.com/help/index.php?pg=kb.chapter&id=51&pgid=296
Les Grottes sont ouvertes d'avril à fin octobre
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