The Alsatian Jura

The border of the Alsace with the Suisse does not rest on any base of a natural nature. The septentrional Virgation of the chain of crumpling of the the Jura indents Alsace of the South, called the Sundgau. It is characterized by a series of links lengthened in the west-east direction, of rock Calcaire, which strip of the depressions cut in the marnes; rivers, the such Release or the Ill, which take in these mountains the source, joins the Rhenish Fossé by a zigzagant layout; They essentially follow of their layout the marly depressions but gain north while passing from the one with the other by throats notched through the links. Who says calcareous, known as phenomena of dissolution of the rock and engloutissement of water, and it is in the Jura that one finds the only phenomena karstic (caves, resurgences of underground and similar rivers) in Alsace. The shelters - under - rock of Männlefelsen, with Oberlarg, of which one is famous for the prehistoric layers that it contains, are an example. They are all in all there the features of landscape characteristic of a good part of the Jura called the “folded Jura”.

In detail, five types of natural combinations can be distinguished:

On the Summit and the tops of slopes of the links:

there where the slopes are stiff, 20° and more, of the grounds very stony, whose character comes from the bursting of the Roche by the Gel during the glacial periods (primarily the last), supports |not very advanced grounds because they are the prey of ablation. These stones are descended along the slopes according to complex processes, associating the fall, the Solifluxion and the slip in the presence of Neige on these slopes then stripped of covering Végétation;

there where the slopes are less stiff, the grounds are less stony because resting on a rather thick been subject to solifluction mass. They are advanced, thicker;

- on the marly low-slopes, the characters are close to those of the not very stiff slopes on limestone, with a stony load still less, but real, because supplied with the descent of the material deîos my slopes limestones which dominate them. They are slopes sensitive to the slips.

the funds of valleys comprise two types of grounds:

- on the noneasily flooded terraces, with the tablecloths of rollers are covered with a courche unequal thickness of silts of overflow. Well developed and deep grounds could be formed there; on the lowest terraces however, they are often affected by a water sticking which gives unfavourable characters to them;

- current beds of Flood, funds of often artificially drained small valleys, show same the characteristics, but only embryonic grounds.

See too

Massive of the Jura
Sundgau

External bonds

Tourist bureau of the Alsatian Jura

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