Sculpted by waters! A natural amphitheatre has been created. Its walls sculpted with gigantic columns 10 – 12 metres high. The fragile and arid landscape represents an ephemeral work. Despite the fact it appears as if it were frozen in time, it is constantly changing. Each time it rains, large quantities of sand are worn away. The ancient shapes are disappearing and new ones appear. Erosion is the architect and despite similar terrain in the area, nowhere else will you find the results as stunning as here. The sand rock columns are hoodoos or “chimney rocks” due to the hard rock layer that covers them, protecting them minimally from a more rapid erosion. Note: many are confused by the local name of “Site des Orgues”. When in fact in geology, the word “organs” is preferably used to designate basalt streams that solidified in long pipes. Yet, there is no volcanic origin in this terrain. It is where the vegetation is sparse that the rock caps are less protective and first gullies were able to form. As the soft layer was reached, it was cut rapidly. The erosion varies and is more intense where the surface is softer on the column whose diameter is reduced. This causes the rock cap to lose its foundation until it eventually collapses as a while or in sections. In the site’s maze you can see and comprehend the importance of the protective rock cap. Whenever the rock cap has disappeared, the columns will soon collapse.
The hoodoos or “chimney rocks” develop more slowly than the gullied sides of the site due to their vertical height: in fact, a drop of water dripping down the side of the hoodoo is carried away by its own weight. It takes with it a grain of sand or a flake of clay and the repetition of this is the action that carves the famous “organ pipes.”
In addition to the existing formation by water erosion, the site reveals a more ancient history. There are five major steps: – The mountain range we know as the Pyrénées was formed approximately 45 million years ago. At that time, the fold extended as far as the Languedoc and Provence. – Approximately 30 million years ago the eastern part of the chain broke and collapsed. The Mediteranean as we now know it first appeared. – Than 5.8 – 5.3 million years ago, the Mediteranean was dried out as a result of an obstruction at the straits of Gibralter which was a result of plate movement. With the waters of the Atlantic unable to enter, the water level fell over 1500 meters. – Since plate mobility is constantly changing this situation lasted a short time. In the Pliocene the tectonics allowed for another shift and there was a marine invasion. Perhaps one could picture the terrain looking like the deserts of Africa. The wildlife present were the as they are in current Africa landscapes. There were Hippopotamuses, elephants, monkeys and of course rodents and the hipparion or small horse. It was a turning point in the earth’s evolutionary climate. Hot climate became drier and the Mediterranean climate began. – The rock cap which covers the columns at the site are composed of rubble resulting from the first quaternary (1.8 million years ago) colds. The cold was consistent with the fracturing in the rocks due to frost. At the foot of icy summits, landscapes are covered with windswept tundra and arid steppes. Only the sheltered locations hosted any softwood, birch and juniper forests. Animals were of the same kinds found in other parts of Northern Europe: wild horses, reindeer, antelopes, bison, saigas, wolves, bears, lynxes, otters, the Artic foxes, and ermines. Some original animals: herbivores such as woolly rhinoceros, mammoth, auroch, herbivores, and carnivores such as cave hyenas, cave lions and cave bears. This action was in the site’s long history before the time of the flowing waters. With the climatic changes reminding the interglacial phases, the last phase (erosion) of this landscapes life is begun. Sand which has been in transit on its way to the sea has been trapped for five million years and will eventually be washed away by rainstorms. This landscape is a heritage and it has travelled through time. While its history may seem ordinary it is in fact the natural mechanisms that have created this most unusual site. It is acknowledged that there are comparable, yet different, sites on the banks of Serre-Ponçon lake (Hautes Alpes), Cappadoce in Turkey and also in Bryce Canyon in North America. The fact is, each drop of water will have a causal effect on this beautiful site. See it now! Bisous, Léa