Sidobre
Encyclopedia
The Sidobre is a mountainous area located in the south of the Massif central
, in central France
. It is a 15.3 km long, 6.6 km wide plateau made of granite
, covered with forests. Its highest point is in the lieu-dit “Le Patau” (707 m.).
, between Lacrouzette, Ferrières, Saint-Salvy-de-la-Balme and Lafontasse, surrounded by the following natural regions :
resulting from a Hercynian intrusion dated back (using the Rubidium-Strontium method
) to 304 ± 8 Ma. The magma cooled down slowly and crystallised at a depth of 7.5 to 20 km. It eventually came to the surface with the erosion of the Cambrian
metamorphic rocks.
In the central part of the massif, the granite is a granodiorite
slightly porphyric
, hence its blue tints, while the outer part is essentially composed of monzonite
.
, thus becoming more exposed to the rhexistasy, which explain the remarkable natural forms and constructions of the site.
The Sidobre, while just adjacent to it, is totally independent from the Montagne Noire
. They are separated by the sedimentary basin
of Castres
and the “Thoré
trench”.
This stunning site, with its dozens of huge strange-shaped rocks, is unique in Europe (other sites exist in France, but in a much smaller scale), and has inspired many legends and tales.
Its granite being used for many purposes: pavements, airport runways, funerary art…
While mass tourism is still uncommon in the area, local tourism
also contributes to the Sidobre’s economy.
The site and its environment have been placed under the protection of the Haut-Languedoc Regional Nature Park
.
Massif Central
The Massif Central is an elevated region in south-central France, consisting of mountains and plateaux....
, in central France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
. It is a 15.3 km long, 6.6 km wide plateau made of granite
Granite
Granite is a common and widely occurring type of intrusive, felsic, igneous rock. Granite usually has a medium- to coarse-grained texture. Occasionally some individual crystals are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic...
, covered with forests. Its highest point is in the lieu-dit “Le Patau” (707 m.).
Location
It is located in the Tarn department, at the South-Western end of the Massif centralMassif Central
The Massif Central is an elevated region in south-central France, consisting of mountains and plateaux....
, between Lacrouzette, Ferrières, Saint-Salvy-de-la-Balme and Lafontasse, surrounded by the following natural regions :
- East : the Mounts of Lacaune
- South : the Montagne NoireMontagne Noire* Not to be confused with the Montagnes Noires in Brittany.The Montagne Noire is a mountain range in central southern France. It is located at the southwestern end of the Massif Central in the border area of the Tarn, Hérault and Aude departments...
- West : territory of CastresCastresCastres is a commune, and arrondissement capital in the Tarn department and Midi-Pyrénées region in southern France. It lies in the former French province of Languedoc....
Geology
The granite of the Sidobre is a plutonic rockPluton
A pluton in geology is a body of intrusive igneous rock that crystallized from magma slowly cooling below the surface of the Earth. Plutons include batholiths, dikes, sills, laccoliths, lopoliths, and other igneous bodies...
resulting from a Hercynian intrusion dated back (using the Rubidium-Strontium method
Rubidium-strontium dating
The rubidium-strontium dating method is a radiometric dating technique that geologists use to determine the age of rocks.Development of this process was aided by Fritz Strassmann, who later went on to discover nuclear fission with Otto Hahn and Lise Meitner....
) to 304 ± 8 Ma. The magma cooled down slowly and crystallised at a depth of 7.5 to 20 km. It eventually came to the surface with the erosion of the Cambrian
Cambrian
The Cambrian is the first geological period of the Paleozoic Era, lasting from Mya ; it is succeeded by the Ordovician. Its subdivisions, and indeed its base, are somewhat in flux. The period was established by Adam Sedgwick, who named it after Cambria, the Latin name for Wales, where Britain's...
metamorphic rocks.
In the central part of the massif, the granite is a granodiorite
Granodiorite
Granodiorite is an intrusive igneous rock similar to granite, but containing more plagioclase than orthoclase-type feldspar. Officially, it is defined as a phaneritic igneous rock with greater than 20% quartz by volume where at least 65% of the feldspar is plagioclase. It usually contains abundant...
slightly porphyric
Porphyry (geology)
Porphyry is a variety of igneous rock consisting of large-grained crystals, such as feldspar or quartz, dispersed in a fine-grained feldspathic matrix or groundmass. The larger crystals are called phenocrysts...
, hence its blue tints, while the outer part is essentially composed of monzonite
Monzonite
Monzonite is an intermediate igneous intrusive rock composed of approximately equal amounts of sodic to intermediate plagioclase and orthoclase feldspars with minor amounts of hornblende, biotite and other minerals...
.
Sites
Originally composed by one single piece of rock, the Sidobre was cracked by the Pyrenean orogenyGeology of the Pyrenees
The Pyrenees form part of the huge alpine orogenic system. This 430 kilometre long, roughly east-west striking, intracontinental mountain chain divides France, Spain, and Andorra. It has an extended, polycyclic geological evolution dating back to the Precambrian...
, thus becoming more exposed to the rhexistasy, which explain the remarkable natural forms and constructions of the site.
The Sidobre, while just adjacent to it, is totally independent from the Montagne Noire
Montagne Noire
* Not to be confused with the Montagnes Noires in Brittany.The Montagne Noire is a mountain range in central southern France. It is located at the southwestern end of the Massif Central in the border area of the Tarn, Hérault and Aude departments...
. They are separated by the sedimentary basin
Sedimentary basin
The term sedimentary basin is used to refer to any geographical feature exhibiting subsidence and consequent infilling by sedimentation. As the sediments are buried, they are subjected to increasing pressure and begin the process of lithification...
of Castres
Castres
Castres is a commune, and arrondissement capital in the Tarn department and Midi-Pyrénées region in southern France. It lies in the former French province of Languedoc....
and the “Thoré
Thoré
The Thoré is a long river in the Hérault and Tarn départements, southwestern France. Its source is in the northern part of Rieussec. It flows generally northwest...
trench”.
This stunning site, with its dozens of huge strange-shaped rocks, is unique in Europe (other sites exist in France, but in a much smaller scale), and has inspired many legends and tales.
Economy
The Sidobre is an important zone of quarrying, representing half of the granite production in France, with about 1,200 employees and 100 companies. The number of quarries has been constantly decreasing since the 1950s, reaching barely fifteen nowadays, though the exploitations have grown bigger. The activity suffers from the competition with China.Its granite being used for many purposes: pavements, airport runways, funerary art…
Tourism in Tarn
From the Gaillac Vineyard to the Sidobre, the Montagne Noire and the stunning Gorges du Tarn, the Tarn department, in the southwest of France, offers a great range of sights and tourist attractions.-Statistics:In 2009, there were :...
also contributes to the Sidobre’s economy.
The site and its environment have been placed under the protection of the Haut-Languedoc Regional Nature Park
Parc naturel régional du Haut-Languedoc
thumb|A mouflon in the park.The Parc naturel régional du Haut-Languedoc is a regional natural park situated in the south of the Massif Central within the Aveyron, Hérault and Tarn departments of France...
.