Moraine

Moraines (French: moraine " scree " ), the whole of the material transported by a glacier, in particular the rubble deposits moved by glaciers as they move or are piled up, and the recognizable in the field formations.

Word origin

Originally, this term was used by the population in the area of Chamonix, the rock so that the walls indicated that had piled up the glacier. In the scientific literature, the term was introduced in 1799 by the glacier Horace Bénédict de Saussure.

In the literature it has become common in recent years, the term " moraine " only to the currently moving material in glacial ice and to relate the forms of relief arising under and around the glacier ice. The deposits (sediment ), however, are referred to as glacial till (or Till ).

Types of moraines

Basically, two types of moraines can be distinguished, the Wandermoränen and the deposited moraines. Wandermoränen are all those who were moved by the ice. Moraines that were not moved after deposit are called moraines deposited.

The Wandermoränen include:

• Obermoränen come from the material that falls from the rock walls of the glacier and deposited during the melting of the glacier, they occur mainly in the ablation zone
• Innenmoränen include all the material that is so transported interglacial inside the glacier
• Untermoränen form at the glacier base. The material of the Untermoräne is very strong ground and crushed by the friction with the ground
• Lateral moraines form along the edges of the glacier tongue. Your material is derived on the one hand by the side bedrock, for the most part but from former Untermoränen that have been conducted on the sides of the glacier
• Medial moraines are formed from the two glaciers when they flow together ( confluence) and unite.
• Bedload is all material that has been moved by ice.

The deposited moraines include:

• Moraines consist of the material of the lower and Innenmoränen.
• Moraines formed as debris accumulation on the glacier end when the glacier front is not moving for a long time. In them you can very well see the greatest expansion of the glacier.
• Satzendmoränen caused by melting of glaciers over a longer period at one point, forming larger walls that remain after the complete melting of the ice impact on the countryside.
• Fließendmoränen are a downstream product of Satzendmoränen if they change through collapse or roll down from their rock material form, ie " flow away ".
• Stauchendmoränen characterize embedded clods of gletscherüberfahrenem material ( frozen ), which is pushed and installed in the non-moving moraine.
• Sohlmoränen are the counterpart of the ground moraines, with no transport has taken place.
• Ablationsmoränen collect material of the melting ice and the top link of the moraine sequence.
• Drumlins are elongated along the direction of movement of the glacier running hills. They consist mostly of deposited moraine, especially of the ground moraine.
• Boulders are carried by the larger ice boulders

After the emergence time are distinguished Jungmoränen ( Weichseleiszeit, Würm ) of Altmoränen ( from the previous ice ages ).

Composition

The term includes all moraine rubble that were carried and deposited by the ice. Moraines consist of material of different grain size from clay to sand to large boulders. The material, however, is mixed and has no sorting or stratification by size usually on.

Also there are end and ground moraine as Sohl, intermediate or top coat mixed and Altgestein. Lateral moraines, which are already deposited moraines, may have a dirty stratification also quite.

Mountaineering importance

Since moraines consist of Wi- caked sand and rock, the steep flanks are often rockfall risk. They are conveniently committed mostly the top of the moraine. Transitions or dismount from a moraine of the glacier, one should carefully choose the least dangerous place and stick to climbing lanes, where such can be seen.

Moraines can also serve as a valuable guide in an otherwise little evidence offered featureless terrain.