A rift is a zone where the continental Lithosphère is in extension, which causes its depression (Graben), a zone of volcanicity and an important continental sedimentation. The morphological expression of this extension is a long trough fault (a Graben ) abruptly bordered of high areas (the shoulders , raised by heating effect). The abrupt edges are the trace large Faille S normals, parallels, the length whose the central ditch crumbled. Relatively high plates, bordered by subsidiary normal faults, can appear in the graben; they are Horst S.

The extension in the rifts is in general associated with the opening of cracks into which magma tholeiitic Alcalin injects, often Bimodal. The rifts are thus normally associated with large volcanos (for example the Kilimandjaro, along the Grand East-African rift).

It is considered that the rifts represent the initial stage of the rupture lithospheric. When this one intervenes, the coat goes up to surface and separates two tectonic plates along a oceanic news wrinkle.

A rift whose evolution stopped before the rupture lithospheric is called aulacogene .

Some rift:

• the graben of the Rhine (or Rhenish Ditch, Germany, Swiss, France)
• the East-African Rift
• the graben of the Bresse
• the rift transantarctic
• the rift Baïkal (Russia)
• the graben of Oslo (Norway)
• the rift of the Río Large (Colorado, New Mexico)

External bonds

• Objective-Ground, the rifts