Limousin plateau
| Limousin plateau | |
|---|---|
 Location map of the Plateau du Limousin in the north-western Massif Central |
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 View over the Plateau du Limousin to the southeast towards the Monts du Fayat |
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| Highest peak | at Masseret ( 480 m ) |
| location | Department of Haute-Vienne and Department of Corrèze (Central France ) |
| part of | Massif Central |
| Coordinates | 45 ° 32 ' N , 1 ° 31' E |
The Plateau du Limousin forms a composite, slightly undulating desk surface in the French departments of Haute-Vienne and Corrèze in the Nouvelle-Aquitaine region .
geography
The Plateau du Limousin, in German Limousin plateau , is located on the northwestern edge of the Massif Central and is bordered to the southwest and south by the Monts du Limousin , whose heights generally exceed 500 meters. Certain rivers cut into the plateau, such as the Vienne , the Briance , the Isle , the Vézère , the Auvézère and the Grêne . The heights of the plateau vary between 250 and 400 meters, with an average of 350 meters. The plateau slopes slightly from east to west and, starting at 500 meters on the western edge of the Plateau de Millevaches , slopes down to around 200 meters in the lowlands of the Charente department .
The Plateau du Limousin occupies roughly the southern half of the Haute-Vienne department, with the Vienne valley forming the northern border. It also extends into the northwestern quarter of the Corrèze department with the Vézère valley as the southeast boundary. More far-reaching definitions extend the plateau itself to the Plateau de la Marche in the north and the Brive basin in the south.
Starting from the Plateau du Limousin, the Charente limousine - a gently undulating hilly landscape embedded between the valleys of the Vienne and the Charente - and the Périgord vert lead over to the Aquitaine Basin .
In the middle of the plateau rise some smaller massifs, such as the Monts de Châlus or the Monts de Fayat . In addition, it can be divided into various sub-plateaus, which can be characterized by specific altitudes and rivers. These include B. the Plateau de Rochechouart , the Plateau d'Uzerche etc.
The Monts de Fayat split the Plateau du Limousin into two parts:
- in their north in the catchment basin of the Vienne as well as subordinate in the catchment basins of the Charente, the Dronne and the Isle
- in their south in the catchment basin of the Vézère.
Both parts communicate by means of a pass around 480 meters high in the municipality of Masseret in the Corrèze department.
Occasionally, the term Plateau du Limousin is associated with other landscapes in the Limousin, such as the Bénévent-l'Abbaye plateau in the Creuse department or the Xaintrie in the Corrèze department, although the latter are completely independent.
Hydrography
Several important rivers have their source on the Plateau du Limousin as it is an essential watershed. The Briance, Aixette , Grêne and Gorre, among others, drain to the catchment basin of the Loire in the north . Watercourses flowing down to the west belong to the Charente catchment area . In the south lies the catchment area of the Dordogne , which flows into the Garonne . The Dronne, Isle and Auvézère flow to it.
geology
Geologically, the Plateau du Limousin belongs entirely to the crystalline basement of the Massif Central. It lies in the generally very highly metamorphic Ligéro-Arvernian zone , which forms the central part of the Variscan orogen and which already began to consolidate in the Upper Devonian through collision. The structural design can be simplified as follows: the plateau lies in a saddle between two parautochthonous bulges in the basement - the Plateau de Millevaches with the associated Sussac Cathedral in the east and the Saint Mathieu Cathedral in the west. This saddle is filled by two rather flat gneiss covers, the lower and the upper gneiss cover of the Limousin. The lower gneiss cover laid in a westerly to south-westerly direction over the Saint-Mathieu cathedral, but was in turn pushed backwards by the upper gneiss cover. The upper gneiss cover is trough-shaped south of Limoges at the height of Nexon and contains ophiolites at its base - remnants of the former Limousin Ocean . It floats, so to speak, on the lower gneiss cover, which is mainly made up of eye gneiss , paragneiss and various leptynites (leucocratic gneiss). The upper gneiss cover appears again further south at the level of Lubersac in the Uzerche synclinory , but here it was pushed back in a northerly direction onto a saddle structure of the lower gneiss cover ( Meuzac anticlinory ).
The southern end of the plateau forms the Thiviers-Payzac unit , which is much lower metamorphic and also shows steep structures.
Two stages can be distinguished chronologically:
- the first saw the closure of the Limousin Ocean between 400 and 360 million years ago (Middle and Upper Devonian). This resulted in the ceiling stacking in a north-south direction, with the upper gneiss ceiling being pushed onto the lower gneiss ceiling. The entire stack of blankets is folded in a north-south direction, the wavelength is around 25 kilometers. Remains of oceanic crust caught between the two nappes, which now mainly occur at the base of the upper gneiss sheet, but can also be found in the lower gneiss sheet ( Merlis serpentinite ).
- In the second stage between 330 and 300 million years (Upper Carboniferous) the Rheic Ocean closed in the north. As a result, the two gneiss layers were pressed together to the south-west over the parautochthon, although the internal flow of material must have taken place to the south-east - recognizable by the clear stretching linear in this direction.
Economic use
The Plateau du Limousin shows tendencies towards the Bocage landscape and is agriculturally suitable for raising cattle. It is particularly known for raising the Limousin cattle . The keeping of sheep and pigs of the Cul noir limousin breed is somewhat less important .