Looking first at erosion, there are two main processes that occur here: plucking and abrasion.
Plucking occurs when ice at the bottom of the glacier melts slightly as it moves. Often, the ice melts around large boulders and then refreezes around them. As the glacier then continues to move, these boulders are ripped up off of the ground and move along with the glacier and contribute to the process of abrasion. This process of plucking leaves behind a very jagged landscape.
Abrasion occurs when rocks become embedded in the base and sides of the glacier itself. As the glacier moves, these rocks rub and scour the bedrock and rock faces, acting much like sand paper. This results in the rock surfaces becoming highly polished with large grooves in them, known as striations.
The above diagram gives a brief illustration of the processes of plucking and abrasion as well as where about on the glacier they would occur (http://www.bbc.co.uk/schools/gcsebitesize/geography/glacial_landscapes/glacial_erosion_landforms_rev1.shtml)
Secondly, we will be looking at weathering, in particular freeze-thaw.
Freeze-thaw weathering occurs when water enters joints and cracks in rocks and then freezes as the temperature drops. As water freezes, it expands and exerts pressure within these cracks and causes them to widen. As temperatures begin to rise again during the day, the water thaws and contracts. This recurring process causes the rock to weaken and eventually they break up. These rock pieces may then contribute to the process of abrasion.
The next section will be transportation.
Material carried within a glacier is known as moraine. Moraine can be transported on the surface of the glacier, known as supraglacial moraine, or internally (englacially). Debris collected from valley sides as the glacier moves is known as lateral moraine. If two valley glaciers meet and then merge together, the lateral moraine of the two glaciers also merges together and forms what is known as medial moraine and runs down the middle of the newly formed glacier.
The image above illustrates the different type of moraine that is transported within a glacier.
Lastly, we will be looking at deposition.
As temperatures begin to fall, the ice within a glacier begins to melt. This therefore means that the glacier cannot carry as much material and so it deposits it. The rocks and boulders that the glacier puts down is known as till or boulder clay and is an assortment of different sized and shaped material (unsorted). The main depositional feature of a glacier is the terminal moraine - material deposited at the very end of the glacier. However, it will also eventually deposit the lateral and medial moraines alongside the ground moraine (debris found at the base of the glacier).
Looking for information on this part of the topic led me to many revision and text book websites which has led me to see that this information is not only readily accessible but also very easy to use and explain. There have been a number of useful diagrams and explanations and some websites have even provided short videos to help show the written explanation. These will all be very useful when teaching as it is sometimes difficult to understand things purely from a written or spoken explanation. Often, within this topic, it is easier to show diagrams and videos as it gives a better idea of what is happening and helps to apply what has been learnt to a real life scenarios.
List of websites used:
http://www.bbc.co.uk/schools/gcsebitesize/geography/glacial_landscapes/glacial_deposition_landforms_rev1.shtml - BBC Bitesize
http://revisionworld.co.uk/a2-level-level-revision/geography/glacial-environments/glacial-processes-landforms/erosion-processes - erosion processes
http://www.pearsonhighered.com/christopherson8einfo/downloads/Christopherson_Chapter_17.pdf - Geosystems, Christopherson
http://www.s-cool.co.uk/gcse/geography/glaciers/revise-it/glacial-processes - S-cool revision
http://education.nationalgeographic.com/education/encyclopedia/glacier/?ar_a=1#page=2 - National Geographic
Looking for information on this part of the topic led me to many revision and text book websites which has led me to see that this information is not only readily accessible but also very easy to use and explain. There have been a number of useful diagrams and explanations and some websites have even provided short videos to help show the written explanation. These will all be very useful when teaching as it is sometimes difficult to understand things purely from a written or spoken explanation. Often, within this topic, it is easier to show diagrams and videos as it gives a better idea of what is happening and helps to apply what has been learnt to a real life scenarios.
List of websites used:
http://www.bbc.co.uk/schools/gcsebitesize/geography/glacial_landscapes/glacial_deposition_landforms_rev1.shtml - BBC Bitesize
http://revisionworld.co.uk/a2-level-level-revision/geography/glacial-environments/glacial-processes-landforms/erosion-processes - erosion processes
http://www.pearsonhighered.com/christopherson8einfo/downloads/Christopherson_Chapter_17.pdf - Geosystems, Christopherson
http://www.s-cool.co.uk/gcse/geography/glaciers/revise-it/glacial-processes - S-cool revision
http://education.nationalgeographic.com/education/encyclopedia/glacier/?ar_a=1#page=2 - National Geographic
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