Deposition Landforms

Well the title might explain, Deposition Landforms are the features that occur when material form the Glacier is laid down. Whether its when the Glacier is still there or once it has retreated.

Rock Flour and Till

Rock Flour:- Rock sediment that has been grounded down to a fine powder. This usually flows out of a Glacier by meltwater streams.

 Till:- refers to an unsorted variety of sediment, clay, gravel and rocks that has been deposited by the Glacier.

Erratics

Unlike River deposits, Glacier deposits are angular and mixed up. Large rocks and boulders can be found on their own rather than in groups, but also they can be found located with other types and sizes of rock. These Erratics are usually a rock type that is uncommon in the area that they have been dumped, for example Erratics that have been found in Norfolk originated in Norway. This helps Glaciologists determine the direction of ice flow and monitor past ice movements across large areas.



http://www.geulogy.com/norfolk/merton-stone-norfolk.html



This image is of The Merton Stone, Norfolk. It is considered to be one of the largest Erratic in England.

Drumlins

Drumlins are elongated hills of Glacial deposits, most commonly Till. They can be up to 1km long and 500 metres wide, and often occurring in groups that are known as a swarm or a basket of eggs. These would have been the debris collected and accumulated under the Glacier, when the Glacier became overloaded with debris and sediment, it would have been deposited. Even though Glaciologists still disagree on exactly how Drumlins are created, they help to indicate the Glaciers movement. Shown in the below diagrams of a Drumlins cross section, one side is quite steep while the other end tapers to the ground, showing the direction of movement.



http://www.bbc.co.uk/schools/gcsebitesize/geography/glaciation/glacial_deplandrev1.shtml



Vale of Eden in the Lake District



I have also added an image of how a Drumlin looks in real life. This was also found on the BBC Bitesize website.



Moraines

When a Glacier melts or retreats, different types of rock are laid down that have been carried along by the Glacier. These deposit piles are called Moraines, there are different types of Moraines depending on where they were deposited.

• Terminal Moraine:- Deposited at the furthest point that the Glacier reached
• Lateral Moraine:- Material that is deposited along side the Glacier, on the side edges.
• Medial Moriane:- Are found at the Junction of two seperate Glaciers that run along side each other.
• Ground Moraines:- are disorganised piles of different types rocks that have no obvious features. These rocks may have been washed out by Glacier meltwater streams or left in situ when the Glacier melted.

Below is a diagram used on the BBC Bitesize website, to illustrate the different types of Moraines:-

http://www.bbc.co.uk/schools/gcsebitesize/geography/glaciation/glacial_deplandrev2.shtml