Glacier tongue
The glacier tongue is the - often tongue-shaped - lower part of a glacier .
Glacial morphology of the glacier tongues
The glacier tongue is often criss-crossed by radial crevasses . In the end, it forms the zone where the ice melts. This often breaks off abruptly and is then called a glacier break - but this form can also occur in the middle of the tongue, where the glacier overcomes a steep step and breaks on the surface.
The glacier tongue does not have to be bare ice; if there is a lot of embedded rubble and the surface has melted, it can also be partially or completely covered by a rock dump , in which case we speak of a rock glacier .
Retreating glaciers leave terminal moraines at their furthest extent - more or less sickle-shaped hills that were formed in front of the glacier tongue. The marginal moraine marks the sideline of the glacier tongue . Other remnants of former glaciers include various other types of moraines as well as other forms of deposits and erosion, such as glacier cuts , trough valleys or boulders . Chunks of ice that a glacier leaves behind when it retreats can form so-called dead ice holes after melting - small lakes that later fill with clayey sediment .
Tongue shapes of the glacier types
Mountain glacier
The glacier tongue is also the place of the glacier where the meltwater stream, clouded by glacial milk, emerges from under the glacier. Often a glacier gate forms from which the water emerges. The sander lies in front of the glacier tongue . There, the material removed by the glacier is deposited in a plain .
Foreland glacier
In the flat foreland glacier , the glacier tongues form the actual part of the glacier. Here one speaks of praise or lobus ('lobe'). Since the glacier is no longer wedged into a valley, it extends in the form of flat - from above - rounded lobes.
Sea glacier
When the end of a glacier is at sea , blocks of ice peel off and swim away as icebergs - the glacier calves . If rocks are still frozen in it, they fall as dropstones to the sea floor when the iceberg melts .
