Well, I didn’t expect to have you today, I thought the group would be doing quick tips for Maths, so I apologise for the rubbish lesson. In fact, as we go on I become even more confused, it is a bit like teaching in the dark at the moment, well an Antarctic Winter,this is the first time for me as well!
Two public announcements.
- The first is that we start coursework next week, links and resources will appear on the blog over the weekend. Your coursework due date is the 4th of December, two weeks to complete your finished product at home; but you will have three lessons next week to draft your work. Please remember to get your parents to sign the coursework letter. This piece is worth around 17% of your exam, failure to hand this in will lose you a valuable proportion of your final mark. I know that you won’t let me down.
- Please also return your Bangor field trip letter and deposit, if you want to go on this field trip. Demand is usually very high and it is first come, first served. Ask any of the Year 11 about the fieldtrip, hard work, but great fun, and a real asset to your geographical knowledge. It is also my birthday week as well, so start saving.
In terms of knowledge we have been focusing on features and processes. In the exam it will ask you about the processes that occur in your extreme environment, we have so far studied ventifaction in the Dry Valleys (I’ll go over this again tomorrow) and basal slippage which leads to the formation of ice bergs. Tomorrow, we’ll look also at contraction of the permafrost layer and the formation of patterned ground and ice wedges. To be honest I’m still struggling to grasp why the permafrost layer contracts in winter rather than expands, but hey that’s tomorrow.
In terms of basal slippage you should now understand
- Ice sheets are developed due to the accumulation of snow, compacting over thousands of years into ice. The ice begins to move towards the sea, due to gravity and the pressure of the weight of the ice above.
- Ice will move in two ways, glaciers are slow moving rivers of ice, they have rock on either side.
- Where the ice moves across the bottom of the continent, friction occurs, which causes melting, the water produced acts as lubrication, causing the ice to move quicker. This is basal slippage and forms ice streams. Ice streams are different to glaciers, in that they have ice on either side, instead of rock.
- As the ice continues to move, it will move out into the sea. The ice floats across the surface of the sea and an ice shelf is formed.
- When the ice shelf extends into warmer water, calving occurs and icebergs are formed.
We also recapped and labeled some features that we have come across before, including nunataks (see image at the top of the post) and sustrugi, I haven’t even mentioned grease ice (shown in the image right) and pancake ice yet! Whoever said that this Pilot stuff isn’t challenging was having a laugh! :0
Today after doing the announcements and sorting our classification of the iceberg mystery, we looked at some futures work with regards to ice sheets, ice streams, ice shelves and the potential impacts of Global Warming. We did a tops and tails exercise. Because the impact of global warming is uncertain, there could be several outcomes
- Ice sheets could become thicker, warmer temperatures may lead to greater precipitation. Remember that the interior of Antarctica is basically a desert, because of the lack of moisture and uplift. This could lead to increased pressure and therefore faster flowing ice streams. The ice shelves would extend, in fact this phenomenon has already been witnessed in some areas of Antarctica, against the trend you would expect.
- Alternatively, warming could lead to thinner ice sheets, this would result in less pressure and therefore ice streams would slow. If so, the ice shelves would begin to disintegrate due to less feed from the ice sheets and higher temperatures.
As we already know, the Antarctic ice sheet holds 70% of Earth’s fresh water, which would have a huge impact on sea levels and you know the rest….
Wow! I haven’t even got onto Spooks which was great tonight, loads of Geography. We are a little behind where I would like to be at the moment, so we need to pick up the pace, alright Tatler and Jack!
So are you getting all this? I apologise if this doesn’t make much sense, I’m tired and struggling for time at the moment.
PS, Homework- Story of an iceberg needs to be completed for next Monday.
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