Ice on the land summary.
- Created by: Georgia Barnaby
- Created on: 29-04-14 20:28
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- ICE ON THE LAND
- Amount of Ice
- The last ice age was in the Pleistocene period. around 18,000 years ago. Could have been up to 20 cold periods.
- Ice spread over Britain as far south as Severn estuary and up to the eastern coast.
- In the rest of the world, Canada, Scandinavia, Greenland and parts of Russia were covered in ice.
- The last ice age was in the Pleistocene period. around 18,000 years ago. Could have been up to 20 cold periods.
- Glaciers
- A glacier is a very slow moving mass of ice through a valley.
- Accumulation: snow advances when more snow collects than melts.
- Ablation: snow retreats when more snow melts than is collected.
- Glaciers erode in 2 ways: plucking and abrasion.
- Plucking is when ice freezes on a rock, so when the ice moves the rock moves with it.
- Abrasion is when rocks and pebbles stuck in the ice grind over the valley floor and sides. Scratches the surface causing striations.
- The glacier moves in different ways.
- Freeze-thaw weathering is when water gets into the cracks in the rocks. The freezing and expanding causes it to break off.
- In summer the ice melts more, which lubricates the glacier and allows it to slide downhill. This is called basal slip
- In hollows where the movement is curved as the glacier moves downhill, this is called rotational slip.
- Bulldozing is when the ice pushes material forward as the ice advances.
- A glacier is a very slow moving mass of ice through a valley.
- Moraine
- Lateral moraine is carried by the side of the glacier.
- Medial moraine is when two glaciers join so that lateral becomes medial in the middle.
- Lateral moraine is carried by the side of the glacier.
- Terminal moraine marks the furthest point the glacier has been.
- Recessional is when the glacial deposits material behind, marking the retreat.
- Ground moraine is moraine under the ice.
- Englacial moraine is moraine trapped inside the glacier; eg. if it falls into a cravats and new snow falls on top.
- Features
- A corrie is an arm-chair shaped hollow in the side of a mountain. Made mainly due to rotational slip
- Tarn is the lake in the corrie when ice melts.
- A pyramidal peak is when three corries back on to each other to form a pyramid-like point.
- A glacial trough (U-shaped valley) has a flat valley floor and steep sides. This is from when the glacier forces it's way through the valley. Leaves truncated spurs.
- Truncated spurs are when the spurs are cut of the ice. Therefore, the valley floor may contain deposited material.
- A corrie is an arm-chair shaped hollow in the side of a mountain. Made mainly due to rotational slip
- Amount of Ice
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