Corrie and associated features

• Corrie: Stage 1 - before glaciation: Snow builds up in a nivation hollow on a north facing slope, the north facing slope provides greater protection from the sun therefore the snow does not melt. As the weight of the snow increases, it gradually compresses into ice, this squeezes out the air and causes crystallised snow called neve and firn.
• Corrie: Stage 2 - During glaciation: Eventually, due to gravity, the ice will move downhill. As it moves downhill it moves in a rotational fashion which deepens the corrie through abrasion and the sides are steepened by plucking and freeze-thaw weathering. (explain erosion processes)
• Corrie: Stage 3 - After glaciation: Eventually the ice will flow out of the hollow, leaving a Corrie behind, sometimes filled with a small loch known as a Tarn, the Corrie is like an armchair shape with deep hollows and steep sides, Ice deposits some of its gathered material at the front of the corrie (moraine) this forms a lip at the back and sides leaving scree slopes.
• Corrie Example: Red Tarn
• Arete formation: First add Corrie formation and erosion processes. An arete is a knife edged ridge of rock that is formed when two corrie's erode back to back towards eachother leaving a narrow ridge. The ridge is further sharpened by freeze thaw weathering which can cause scree slopes to form.
• Arete Example: Striding edge.
• Pyrimidal peak formation: First add Corrie formation and erosion processes. Pyrimidal peaks are formed when three or more corrie's surround a mountain and erode backwords into it. This carves a pyramid shape with steep walls. Freeze thaw weathering can sharpen the peak and also form scree slopes.
• Pyramidal peak example: Matterhorn