I have used information from mainly http://www.nsidc.org/ and the http://www.geography-site.co.uk/ to try and condense the vast amount of information there is to fairly simple terms. These will allow students and me alike to understand and remember what type of glaciers there are. I will also be using images as well, which will hopefully show us what they look like.
ICE SHEETS:-
Ice sheets are only found in the Antarctica and Greenland. These sheets are huge Continental masses of glacial ice and snow that are larger than 50000 square kilometres long and up to 4200 meters dense in some areas. As these sheets are so dense, they cover over the whole terrain with the exception of the trans antarctic mountains
Below I have attached illustrates of both Greenland Ice sheet and Antarctica Ice sheet using images from the NASA photo gallery http://www.nasa.gov/
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| Greenland and surrounding Ice Shelves |
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| Antarctica and its Ice Shelves |
ICE SHELVES:-
Ice shelves occur when Ice sheets past the land surface and further extend out over the sea and float on the water. These Ice shelves surround most of the antarctic continent, which can be shown in the above image of Antarctica. It is at this area of the Glacier where calving can take place, calving is where ice breaks off at the end of a Glacier. At the Ice Shelves, the sea weakens the Glacier and can cause massive bits of Ice to break off, fell into the ocean and cause Icebergs.
ICE CAPS:-
Ice caps are smaller versions of Ice sheets, covering areas that are smaller than 50000 square kilometres. They are more commonly formed in polar and sub-polar regions that are relatively flat and high altitude. Similar to Ice sheets, Ice caps will cover the land completely but at certain parts of the year some bedrock can be seen. Below is an image of Vatnajokull Glacier, which is Iceland's biggest Glacier and the second biggest in Europe. Underneath this 8100 square kilometre Ice cap Glacier is seven hidden volcanoes, which most are active.
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| Vatnajokull Glacier, Iceland http://iceland.vefur.is/iceland_nature/glaciers_in_iceland/vatnajokull.htm |
Ice fields are similar to Ice caps, however ice fields are effected by the topography of the land below. An Ice field may span over many mountain peaks or even a mountain range. Below is an image of Kalstenius Ice field, located on Ellesmere Island, Canada, The Ice field produces multiple glaciers that flow into a larger valley glacier. (Royal Canadian Air Force photograph at the World Data Center for Glaciology, Boulder)
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| Kalstenius Icefield, |
Last but not least is Valley Glaciers. These glaciers originate from Ice fields or Ice caps that spill downhill. As you can see in the above picture of the Ice field, Valley glaciers look 'much like giant tongues' (http://www.nsidc.org/) that usually flow down existing steep V- shape valleys that have been previously eroded from rivers etc. The sheer pressure of these glaciers cause the V-shape valleys to erode and enlarge into flat bottomed U-shape valleys. These valleys are a common sight around the world today from past Glaciation periods. Valley Glaciers can be very long and flow far enough to reach the sea, this is then known as a Tidewater Glacier. Tidewater Glaciers are responsible for calving small icebergs that are not as big as Icebergs from an Ice Shelves but can still cause problems.
Below is a Picture that I took of Franz Joseph Glacier in New Zealand, that hopefully illustrates a Valley Glacier being constraint by steep Valley walls. Also from the http://www.nsidc.org/ gallery is a image of a tidewater Glacier.
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| Lamplugh Glacier, Alaska Tidewater Glacier, that shows pieces of Ice debris in the Water http://www.nsidc.org/ |
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| Franz Joseph |
There are many other types of Glaciers which can be found on http://www.nsidc.org/ and http://www.geography-site.co.uk/ however I felt that these were the most common and more important. Also this post would be a mile long if I added all types of Glaciers.
Task for Students
Each Student would be assigned a different type of Glacier, as homework or during lesson time they would research the particular glacier. They would then present the Glacier type to the class. This will encourage self learning as well as allowing students a chance to present in front of their classmates
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