Geography: Glaciers

1. Erosion
1. Glaciers pick up material in 2 ways: 1) the ice freezes around rocks & stones under glaciers. Then it tugs or plucks them out. 2) The plucked rocks & stones scrape bits off the glacier bed, as they are carried along. This is called abrasion.
  1. Freeze-thaw weathering makes plucking easier. First, water under the glacier freezes in cracks of rocks. The cracks fill with water. It freezes again. The ice thaws again. And so on...... until the cracks are so big it break the rock.
2. Transport
1. The glaciers carries away the material it has eroded.
  1. 1) As the glacier pushes along, material that falls onto it is carried on top. 2) Some is carried inside the glacier. Ex: debris that fell into crevasses 3) A lot of material is frozen into the base of the glacier.
3. Deposition
1. As it goes down a mountain, it gets warmer, so eventually the glacier reaches a place where it melts.
  1. As the ice melt, the load it's carrying falls to the ground- as rocks, stones, sand & clay, all mixed up. This mixture is called glacial till.
    1. The water from the melting ice is called meltwater. It runs off & will feed a river or a lake. Meanwhile, higher up in the mountain snow keeps on feeding the glacier. So it keeps on flowing down to the place where it melts.

Resource summary

	Created by Yu-Qing Tham about 8 years ago