6-832: The Limagne graben is a graben structure that formed during the Eocene as part of the European Cenozoic Rift System . It forms the Limagne plain in the Massif Central and is filled with up to 2 kilometers of sediment. The Limagne graben formed from the Eocene to the Oligocene as the part of the European Cenozoic Rift System (ECRS) which extends offshore as the Gulf of Lions and Valencian trough. The ECRS also includes
12-417: Is a valley with a distinct escarpment on each side caused by the displacement of a block of land downward. Graben often occur side by side with horsts . Horst and graben structures indicate tensional forces and crustal stretching. Graben are produced from parallel normal faults, where the displacement of the hanging wall is downward, while that of the footwall is upward. The faults typically dip toward
18-775: The Upper Rhine graben, Rhône graben, Saône graben, Lower Rhine Embayment and Leine graben as well as the Eger graben in the Bohemian Massif. The Limagne graben is part of the larger Limagne subsidence area, which extends southward from the Burgundy rift-rift transform into the Massif Central with a large number of small grabens. Thermal doming and volcanic activity in the Miocene uplifted the Massif Central, effectively ending subsidence and halting
24-438: The build of lake sediments in the graben. Graben In geology , a graben ( / ˈ ɡ r ɑː b ən / ) is a depressed block of the crust of a planet or moon, bordered by parallel normal faults . Graben is a loan word from German , meaning 'ditch' or 'trench'. The first known usage of the word in the geologic context was by Eduard Suess in 1883. The plural form is either graben or grabens . A graben
30-405: The center of the graben from both sides. Horsts are parallel blocks that remain between graben; the bounding faults of a horst typically dip away from the center line of the horst. Single or multiple graben can produce a rift valley . In many rifts , the graben are asymmetric, with a major fault along only one of the boundaries, and these are known as half-graben. The polarity (throw direction) of
36-419: The main bounding faults typically alternates along the length of the rift. The asymmetry of a half-graben strongly affects syntectonic deposition. Comparatively little sediment enters the half-graben across the main bounding fault because of footwall uplift on the drainage systems. The exception is at any major offset in the bounding fault, where a relay ramp may provide an important sediment input point. Most of
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