Formation of a Corrie. Small hollow on the north facing side of a hillside Water enters cracks in the rock. when temperatures fall below zero the water

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Formation of a Corrie Slide 2 Small hollow on the north facing side of a hillside Water enters cracks in the rock. when temperatures fall below zero the water freezes and expands putting huge amounts of pressure on the surrounding rock. When temperatures rise again the water melts releasing the pressure. This process is known as freeze-thaw. This weakens the surrounding rocks. Slide 3 Snow begins to collect in the hollow, and soon turns to ice in the falling temperatures. As snow continues to fall, the ice overflows out of the hollow to form a glacier Slide 4 GLACIER The glacier freezes onto the surrounding rocks, that have been weakened by freeze-thaw. As the glacier moves downhill due to gravity, it tears away these rocks. This process is known as Plucking Direction of Ice Movement Slide 5 Huge amounts of rock are torn away from the hillside, leaving a huge hollow. Slide 6 Rocks embedded within the glacier scrape against the rock surface, acting like sandpaper, smoothening the surface. This process is known as abrasion. Slide 7 After glaciation, a small mound of moraine is left, forming a lip Original profile, before glaciation After glaciation, a huge hollow in the hillside, called a corrie Slide 8 Often meltwater remains in the corrie, known as a tarn or corrie loch Slide 9 Slide 10 Formation of a U-Shaped Valley Slide 11 Before glaciation, U-Shaped valleys are V-Shaped river valleys. Water enters cracks in the rock. When temperatures fall below zero the water freezes and expands putting huge amounts of pressure on the surrounding rock. When temperatures rise again the water melts releasing the pressure. This process is known as freeze-thaw. This weakens the surrounding rocks. Slide 12 Snow and ice begin to move through the valley floor as a glacier. Slide 13 The glacier freezes onto the surrounding rocks, that have been weakened by freeze-thaw. As the glacier moves downhill due to gravity, it tears away these rocks. This process is known as Plucking Slide 14 Huge amounts of rock are torn away from the valley sides and base, leaving very steep sides and a flat base. Slide 15 Rocks embedded within the glacier scrape against the rock surface, acting like sandpaper, smoothening the surface. This process is known as abrasion. Slide 16 Original profile, before glaciation After glaciation, a U- Shaped valley has been formed, with steep side walls and a flat base. Slide 17 Slide 18 Name 3 similarities between the formation of a Corrie and the formation of a U-Shaped Valley Freeze Thaw Action Plucking Abrasion Slide 19 Before GlaciationDuring Glaciation After Glaciation Slide 20 Slide 21 Task 1: Using the information that you have just heard and your notes, answer the following question; Select one feature of glacial erosion and explain the processes involved in the formation of this feature. Annotated diagrams may be used. 4 marks