Occurs where there is a reduction in the gradient of the valley floor, leading to ice deceleration and a thickening of the ice mass. At such points, ice erosion is at its maximum.
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Extending Flow
Occurs whenthe valley gradient becomes steeper. The ice accelerates and becomes thinner, leading to reduced erosion.
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Basal Flow
As a glacier moves over bedrock, there will be friction and this, combined with the pressure of overlying ice, results in melting. This meltwater acts as a lubricant , allowing the ice to flow more rapidly
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Surges
Occurs occasionally when there is a build up of meltwater under a glacier leading to the ice moving formand rapidly, perhaps by 250-300 metres a day
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Internal Flow
Occurs when ice crystals oriente themselves in the direction of the glacier's movement and slide past each other. As the surface ice moves faster, crevasses develop.
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Creep
Occurs when stress builds up within a glacier, allowing the ice to behave like plastic and flow. It occurs particually when obstacles are met
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Rotational Flow
Occurs within the corrie. Herer ice moving downhill can pivot about a point, producing rotational movement. This, together with the increased pressure of the ice, leads to greater erosion and over-deepening of the floor.
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