Vercors Caves —Diving the Karst Systems of Southeastern France Text and photos by Claudia Weber-Gebert 56 X-RAY MAG : 69 : 2015 EDITORIAL FEATURES TRAVEL NEWS WRECKS EQUIPMENT BOOKS SCIENCE & ECOLOGY TECH EDUCATION PROFILES PHOTO & VIDEO PORTFOLIO feature Vercors The cliffs at Presles in the Vercors mountain range of southeastern France (left) PREVIOUS PAGE: William Thumy of Dive Xtrême in Isére, France, leads cave diving trips in the Vercors declared a natural preserve. As for flora and fauna, one will find alpine plants and animals that are eradicated elsewhere in Europe. The plateaus and valleys provide habitat for eagles, various birds of prey and vul- tures, alpine ibex and mar- mots. More recently, lynx and wolves have also been reset- tled here. Alpine plants such as edel- weiss, gentian and carline The karst area of the The access road to the Vercors mountain area penetrates the narrow gorges, where the restricted range is located in the road was partially carved foothills of the French out of the rock to form tun- Alps, bordered on the nels. Coming from the south east by Grenoble and via the little village of Die, the road serpentines up the on the west by Valence slopes of the plateau. Only in the Rhone Valley. size-restricted vehicles are authorized to use this road. It is an insider’s tip that found Tourists in buses are therefore this location where tourism excluded. has grown very slowly. There is The Vercors, divided into barely any industry, and there two parts by the canyon of are no congested roads, no the river, La Bourne, compris- large concrete tourist centers es an area of approximately and just one small supermar- 1,350 sq km: the north, which ket. Quiet and contempla- has opened up and been tive, the area is characterized developed for tourism, offers by traditional crafts, agricul- all kinds of sporting activities; ture and tourism. The region is and the south, which is still frequented by scientists and wild and pristine. mountaineers, hikers, base Parts of the narrow, restricted road up to the Vercors jumpers, speleologists, bat Flora and fauna high plateau is cut out of the rock. Due to low over- researchers and cave divers. In the early ‘70s, Vercors was head, vehicles over 2.5m are not permitted The winding, serpentine road from the town of Die ascends the high plateaus of the Vercors 57 X-RAY MAG : 69 : 2015 EDITORIAL FEATURES TRAVEL NEWS WRECKS EQUIPMENT BOOKS SCIENCE & ECOLOGY TECH EDUCATION PROFILES PHOTO & VIDEO PORTFOLIO feature Vercors thistle occur there, but a special feature deposits. Five caves have so far been are the 60 species of orchids, of which made accessible to visitors: Grotte de the well-known lady slipper’s orchid is Choranche, Grotte de Thaïs, Grotte only one. de la Luire, Cuves de Sassenage and The Vercors boasts some 2,000m Scialet de Draye Blanche mountains, of which Mont Aiguille at So, how did the karst area in the 2,086m is not the highest, but probably Vercors and these stalactite formations the best known, as it was the cradle develop? In the Mesozoic Age—about of Alpinism. It was in this region that 250 million years ago when this area alpine mountaineering was “invented” was still below sea level—reef lime- in the beginning of the 15th century by stone was formed and layers of marine Charles VIII. At that time, the mountain deposits were created. This included was conquered by ropes, hooks and snails, mussels and other marine life ladders. Even today, many hikers and (now visible everywhere as fossils in the climbers come to the region, which by different rock layers). its status as a nature park, still shows In the Tertiary period, about 65.2 mil- a reasonably intact natural mountain lion years ago, rises and folds through landscape. tectonic plate processes were pro- duced by the pressure of the African Caves plate on the Central Europe plate. Particularly impressive in this region is Today, we can see the effects of these the karst system with its natural attrac- processes evidenced in the more than tions: the numerous stalactite caves 300m steep cliffs and drop-offs of the with their bizarre structures of calcium plateaus. THIS PAGE: Scenes from the Choranche Cave in the Vercors mountain range of southeastern France Folds in the earth created in the Tertiary era 58 X-RAY MAG : 69 : 2015 EDITORIAL FEATURES TRAVEL NEWS WRECKS EQUIPMENT BOOKS SCIENCE & ECOLOGY TECH EDUCATION PROFILES PHOTO & VIDEO PORTFOLIO feature Vercors Rainwater, seeping through At the same time, a reverse pro- It is crystal clear and the plateaus, has carved out the cess takes place. The lime-satu- filtered—of the highest wonderful formations in the caves. rated solution dripping down from water quality. In a nutshell, this process can be the cave ceiling leaves deposits The cave of explained as follows: Carbonated on cave ceilings and floors, which Choranche was dis- calcium is released from the lime- form into stalactites and stalag- covered in 1871, when stone, caused by carbonic acid mites after millions of years. The during a draught, in the water, and corrosion takes calcareous water forms gutters the inhabitants of place. Deeply penetrating water when flowing on the ground, some Choranche were leads to leaching of dissolved cal- of them also have bizarre shapes. searching for the cium carbonate, thereby forming These wonderful and unique forma- source of the Gournier large cavities in which water col- tions attract many visitors. River. Water came out lects and flows. of a gap in the rock. Choranche Cave After having cleared As can be clearly away loose scree, the seen on the 3D model inhabitants found a in front of the cave narrow corridor that of Choranche, the ended in a large hall water runs off and with a subterranean only gets out above sea. The two under- the ground when it ground rivers, Coufin strikes a waterproof and Chevaline, flowed together Choranche—after the water level barrier. Until then, here. During the draught, there had dropped again in another THIS PAGE: Limestone formations in Choranche Cave lit by LED display the water flows pre- was access to this hall. Only 20 period of draught. include fistula hanging from the ceiling (above) and stalactites and dominantly vertically years later, the pioneer and spe- Today, about 100,000 people per stalacmites that have merged to form pillars (top right); Over long through a 300 to 500m leologist Oscar Descombaz (circa. year visit the cave of Choranche periods of time, various cave structures are formed by water dripping thick limestone layer. 1866-1914) explored the caves of and explore the natural wonders down through the rock and leaving calcite deposites (right) 59 X-RAY MAG : 69 : 2015 EDITORIAL FEATURES TRAVEL NEWS WRECKS EQUIPMENT BOOKS SCIENCE & ECOLOGY TECH EDUCATION PROFILES PHOTO & VIDEO PORTFOLIO feature Vercors Bournillon Cave entrance (above and right); 320m waterfall at Bournillon Cave; Gours, or rimstone dams of calcite, are formations found in Choranche Cave (left) Choranche are the numerous thin fistula ceiling. The water then accumulates that hang from the ceiling like straws, in underground lakes, which flow out growing only approximately 5cm over through these gours—a bizarre world is 100 years. These fistula resulted from the formed. constant flow of water in the grotto, as the water descended slowly, but con- Bournillon Cave tinuously in these tubes. The longest of The Grotte de la Luire at 45km is the these fistulas has a length of 3.2m. longest cave system of the Vercors. Stalactites and stalagmites in this During wet seasons, the level may rise cave are of different sizes and lengths, up to 450m in this transitional system. and some have grown together over It drains into the Grotte de Bournillon, millions of years into large columns. an impressive cave near Châtelus with In the “cathedral” of the cave sys- a ceiling height of 140m. The size of tem—an impressive space around 50 the cave opening is very impressive, by 80m in size—there are numerous ter- especially the pink rocks of the vaulted raced formations cascading down like ceiling that forms the largest cave in on paved paths and under the super- tacularly staged, since 2013, with mod- stairs. These are round gours, or rimstone Europe. vision of the cave guides. The part ern LED technology. dams (cave formations of calcite), into Nearby, the largest waterfall in opened for tourism is well-lit and spec- The peculiarity of the Grotte de which water drops steadily from the Europe, at 320m in height, can be seen. 60 X-RAY MAG : 69 : 2015 EDITORIAL FEATURES TRAVEL NEWS WRECKS EQUIPMENT BOOKS SCIENCE & ECOLOGY TECH EDUCATION PROFILES PHOTO & VIDEO PORTFOLIO Fistula cave formations hang from the ceiling in Choranche Cave (left); Detail of stalactite (lower left) in Choranche Cave, created by Vercors feature water deposits of calcite over time Map of Choranche Cave Civilization has taken advantage of the such as antenna or whisker-like barbels to huge volume of water passing over the great scan the environment, and thus to “see” in height of the cliffs here, with a power plant the dark. generating electricity. Further down the val- The animal most associated with caves, the ley, the water is dammed again, and the olm (proteus) or aquatic salamander, is found resulting reservoir serves as a water supply for in Choranche only sporadically in under- the region. ground pools, as it is endemic only in the caves of the Balkans in what is now Slovenia. Unique species In other regions, these creatures are not to be In the part of the Bournillon cave that is not found, unless they are exhibited in aquariums.