Well it was all a bit strange today, it was intense, then mad, then it spiralled to an ending. These comments aren’t about the students, they are just about me!

We started with the famous starter for ten, this time guess the landform or feature. The Japanese albedo cartoon caused some murmurs! Finally we completed Palin, interesting fact today was his ability to walk around the world in eight seconds at the South Pole. There is a quick video on this website here. There were ironic cheers when I announced that his was the last episode, not the way to treat the ambassador for school Geography!

We then looked at Ventifaction in more depth, we started with the excellent image at the start of the post, source here. Matron! They cried. We discussed  how sand particles and small rocks abraded rocks in the McMurdo Dry Valleys. Ricky Rock was used as an example. Remember Ricky’s bottom was abraded but his face was left smooth, all to do with the wind direction. I became over animated at one point and Axl destroyed my chalk saucer! We also discussed how ventifacts are classified according to the number of faces that are abraded by the wind. During this we took some notes and produced some annotated diagrams. Not very pilot, but hey! Remember, ventifacts are rocks eroded by the wind.

We then went onto look at another process, permafrost contraction, which leads to the formation of ice wedges and patterned ground in the McMurdo Dry Valleys. We said that in Antarctica the ground is made up of an active layer that defrosts in summer, because the temperatures rises slightly above zero and a permanently frozen permafrost layer.

• In winter this permafrost layer contracts due to the cold temperatures, this also produces cracks that occur in the active layer.
• In summer the active layer defrosts and water makes its way down into the permafrost, where it freezes to form ice wedges.
• In winter the permafrost again contracts and this enlarges the cracks, allowing larger ice wedges to form and so on…
• As the ice wedges form, some material is forced up and to the sides of the cracks, this forms little piles along the edges of the cracks, this help demark the distinct polygon shaped surfaces. (See image below) These little heaps also act as barriers for any wind blown material.

I don’t think I really explained this well, and I was a bit manic over the contraction, did you understand this?

Finally, we started work on our story of an iceberg. I think we could have got more out of this lesson, but to be fair, some of you did start drafting your Antarctic scientist job adverts.It was also nice to be a little more relaxed, remember next week you will be under examination conditions as you begin your coursework! I’m looking forward to what you produce, you are all very capable, so your mark will reflect your effort!

I suggest that you may wish to go over and look at Alan’s Pilot Blog, they have also been looking at processes, but in the context of the Arctic, it would make a nice comparison read.

Remember on Monday that your iceberg sheets need to be handed in, as does any Bangor money or outstanding coursework letter.

Finally, remember three processes in Antarctica you have studied for the exam…

Ventifaction erosion.

Basal Slippage.

Permafrost contraction.

P.S.

Ice weeedge! (Not a process ; )

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Posted in Extreme Environments, Lesson evaluations
Written on Tue, 14 November 2006 at 10:49 pm

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