Glaciation

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Formation of a Drumlin

Drumlins are egg-shaped hillocks of unsorted glacial till which are often found in swarms.There are many theories in relation to the formation of drumlins, but they are found a short distance away from the receding glacier ice and record the final direction of ice movement. Drumlins can be anywhere between 50m high and 1500m long, the stoss end is the steepest and slopes down to the lee end.

The most popular theory is that the glacier is overloaded with moraine, and so struggles to cope with transporting such an amount in the lower parts of its course. Thus, the moraineis deposited. The characteristic elongated shape is thought to be related to the direction of ice movement. Moraine contained within the drumlin tends to be oriented to reflect this pattern It is believed that obstacles in the path of the glacier may be responsible- encouraging the deposited material to be moulded into the characteristic elongated shape.

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Formation of Kames

Kames are formed when water flows over a glacier, and falls into crevasses within the glacier, leaving channels of sediment inbetween where the ice is. Once the glacier melts away kames are left behind and tend to be deposits of sand and gravel at the front of the melting ice sheet. These are unjulating unsorted mounds, as they tend to collapse when the ice around them melts away so they wont be supported.

Kame terraces are frequently found along the side of a glacial valley and are the deposits of meltwater streams flowing between the ice and the adjacent valley side. These kame terraces tend to look like long flat benches, with a lot of pits on the surface made by kettles. They tend to slope downvalley with gradients similar to the glacier surface along which they formed, and can sometimes be found paired on opposite sides of a valley.

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