Revision - Tectonics

Apparently our exams are coming up? I don't really know, I think Millie said something about doing 7 hours of revision a week. That sounds a bit extensive to me, I'll give it a few more weeks until I start...






So I am going to start delving back into my favourite topic and prove my nerdiness to the world as I get excited by the Laki eruption of 1783 (and the synoptic links it offers), the Wilson cycle, the possibility of predicting earthquakes etc. I'm like a child before christmas. 


The first topic shall be... (drum roll)


THE EVIDENCE FOR CONTINENTAL DRIFT AND IT'S RELATIVE USEFULNESS 


So alrighty then, lets get this show on the road. Firstly what is continental drift? Continental drift is the movement of the Earth's tectonic plates in relation to each other, this can be moving towards each other, away from each other or laterally against each. 

Geologists (and aristocrats with nothing else to do) often identified the simplest evidence for continental drift. This is the fact that certain coastlines match with each other, for example in 1620 Sir Francis Bacon recognised that the coastlines of East South America and West Africa were closely related (though he failed to note that they can also form the tectonic rex...). This represents the first piece of evidence that can be used to prove continental drift, matching coastlines to each other. This however is very subjective which makes it unreliable and can match coastlines that are completely unrelated for example the UK looks as if it could slot quite snugly into the Gulf of Carpentaria (other people may disagree, illustrating the subjectiveness). What this evidence does allow is for further investigation, it's a cheap method of identifying areas which may be worth looking into. 


Biology and Climate have also been used to identify and help prove continental drift. By finding common fossils in vastly distant locations such as the Mesosaurus (which has been found in both Brazil and South Africa) we are able to distinguish that these locations were once connected. We can interpret these locations as being connected due to the traits of evolution, the chances of the same species evolving simultaneously in separate locations is almost impossible. A prime example of why we interpret evolution this way is by examining Madagascar. Madagascar split from Africa 160 million years ago meaning it's flora and fauna evolved independently of the rest of the world's. This has resulted in species similar to those found elsewhere but actually not related, for example the Tenrec which is often mistaken as a common hedgehog. This is an example of species filling the same niches in different areas but not evolving commonly, crucial to establishing the continental drift theory. 

The diagram illustrates sea floor spreading and how it can be
measured using palaeomagnetism

The discovery of the Mid-Atlantic Ridge in 1948 helped provide evidence for continental drift. Along the ridge there is a line of volcanoes which is where new oceanic crust is created, thus if oceanic crust is being created then the Earth is getting bigger but it's not. Therefore it must be being destroyed in a separate location. This, when coupled with the discovery of sea floor spreading in the 1960s provides (arguably) the strongest evidence for continental drift. Investigations into sea floor spreading were made possible with the development of Radio Carbon 14 dating (RC14) which has proven that as you move away from the mid-ocean ridges the age of the rocks increases. The final piece of 'modern' evidence for continental drift is Palaeomagnetism. This was discovered in the 1940s due to use of military SONAR equipment and then then theorised into what we understand today by Fred Vine and Drummond Matthews. Palaeomagnetism explores the concept that when iron bearing magma cool below the Curie point the iron within the rocks acts a "fossil compass" pointing towards the prevailing global magnetic field (the Earth's magnetic field switches between North and South and vice versa, every 400ka) . If the sea floor is spreading then the oceanic crust should show symmetrical magnetic stripes as you move away from the mid-ocean ridge. 


I reckon that's enough to be getting on with at the moment, if anyone has any questions feel free to ask away, we're here to help. I'm off to procrastinate instead of doing revision.

Millenium development goals

So I have decided that I am going to start posting summaries and clippets of A2 geography starting at the beginning of the year,

Our first topic of the year was development so this is where I will start!

LDC’s

These are defined by a few key factors,

-income below $750 per capita per year

-very weak resources

    - i.e healthcare, education, nutrition/calorie intake

-economic vulnerability

    i.e –instable exports and instable agricultural production

these are generally associated with a corruption, dictatorships and conflict.

There are currently 49 countries classified as LDC’s this is divided with 33 in Africa, 15 in Asia and 1 in Latin America (Haiti).

-          16 of these are landlocked and 12 small islands

So the question is what is being done to help these countries?  the answer is millenium development goals.   These are a set of 8 goals set up by 192 united nation members who were  hoping tgo achieve them all by 2015 however each one has their own set of deadlines.

   The first goal:

   -To halve the proportion of people whose income = below $1/day

         -this was set to start in 1990 and be achieved by 2015

  -To achieve full and productive employment and decent work for all

        -reasons? when people lose their jobs it leads to vulnerable employment where human rights are comprimised

       - Halve the proportion who suffer from hunger

                -1990-2015

Achieved by:  subsidy programmes in Malawi and Ghana for fertiliser and feeds

                        Malawi need 2.2 million tonnes for self sufficiency

UNDP- supporting national, rural employment gurantee scheme-India

                                      - Providing a minimum of 10days work a year

Goal 2:  ensuring children everywhere are able to complete primary education by 2015

                    -sub saharan africa and South asia

Being achieved by:

-fees abolished in 8 countries-- Tanzania, enrolement ratio doubled to 99.6% in 2008

-world programme-providing school meals

      -encourages parents to send the children to school

EU- basic education in Africa programme- to adopt legal frameworks guranteeing 8-10 year olds uninterrupted education

for goal 2 to be achieved goal one needs to be achieved first.

Goal number 3!

-elimintaing gender disparity in primary and secondary education
       -2015

-Giving women more time to achieve-
      -Diesel run generators burkino faso - frees up womens time.




Goal 4:

-Reduce under 5 mortality rate by 2/3rds. 1990-2015

Achieved by

   -Immunization programmes- Egypt, Vietnam and Bangladesh

  

   -Mosquito nets provided to reduce malaria

              - Republic of Congo

 Goal number...5!

Reduction of maternal mortality by 3/4

      -1990-2015

Achieved by:

- investing in mobile maternal health units

                -e.g. Pakistan

-achieve universal access to productive health care

Goal 6:

To halt and begin to reverse the spread of HIV/AIDS by 2015

Achieved by?

   - access to treatment for thos ethat need it

   - free access to antiretrovial treatment

                   -e.g Botswana-- increase Life Expectancy by 4years

                                          -reduce new cases of HIV

Number 7:

-To halve the population without sustainable access to safe drinking water and basic sanitation

Achieved by:

    -UNICEF- water quality survelance

                    -promote low cost sanitation

                    - promote and improve sanitation in schools

Goal 8:

-Develop an open,rule based, predictable, non-discrimintary trading and financial system

                - Deal comprehensively with debt issues

 

Achieve by?

-UN conference, south-south cooperation

           -co operation thgrough aid, trade technical assistance and investment

                              -- encourages countries of the south to advance valuable partnerships

So this is the first of the many posts to come on development, i hope reading this will start to jog your emory back to last July!!!



Iceland

So in our last post we seemed to forget the very first day just after we landed, we visited a spa which definitely had a distinct smell of rotten egg! after showering vigorously and playing with the pretty cool technology that was the lockers (yes even i think that this piece of technology was kind of trippy) we bathed in the smelly waters which were heated through geothermal means and thus were lush! during the odd occurence of swimming in such odd water (i mean if water smelt that bad in the uk and had that same bright blue/ milky appearance would you even think about putting on your bikini and taking a dip-no i didn't think so!) we then continued to smear white clayish mud all over ourselves and our faces because it is meant to be good for the skin! (my skin most certainly is not feeling any better for it but who doesn't love the excuse!) lastly even frozen pieces of volcano were being spread onto peoples faces!

  Iceland has some of the most stunning views and beautiful landscapes that i think i have seen so far, the sheer diversity and surprise in weather conditions is truly awesome!

Since i landed in iceland i have been sat on a coach driving on complete flat yet surrounded by stunning snowy mountains... the waterfalls aren't half bad either!!! We have been to see many waterfalls in the past two days one of which we got to walk behind and stand under, one of the others we were able to view from the top and see a petrified troll (what else i mean really!) i stood as close to the bottom of this particular waterfall as possible without swimming in the vast plunge pool, the power in the spray  of it was immense. The next waterfall was different and unique again with the waterfall flowing over columnar basalt-- columnar jointing caused as molten rock cools (usually basalt) and contracts.

the rest of today was spent with us walking around a lagoon coming from the glacier the lagoon contained many icebergs and seals as well, the beauty of this was outstanding, the simple contrast of blue waters and crystal clear ice.

EEEEK whilst i have been writing this blog, which happens to have now been for the past hour, i have been interrupted with people running in and shouting that the northern lights are outside-- they are stunning! so on this note the people are trying to shut up this room, it is quarter to twelve and i need some sleep before glacier walking tomorrow!

so long farewell!

The alternative geography lesson

During what would have been during todays lesson we were scrambling around a cave. A cave covered in an inch of ice, which is very slippery and very scary.

Apparently it's not supposed to be that icy and our Icelandic tour guide kept telling us it's only a "little slippery".  He was lying, it was a death trap in there. The only way forwards was to bum shuffle-fact! But to be honest it was one of the most exciting things we haver ever done and very very enjoyable. The fact that it was so icy made it more exciting and made us group together more as a team. That led us to sing most of Bohemian Rhapsody, the Bed Intruder Song and (to James' disgust) some Take That (which I refuse to link to). Eventually we made it through the cave after some tricky climbing only to be faced we a crawl through the smallest gap imaginable up some ungrippable snow...


We were actually caving through a lava tube which formed about 4000 years ago. This formed by basalt lava flows cooling on the top and sides providing insulation for the centre which can remain active for several years. Lava tubes on Hawaii are still active and they work for a long time. Lavascicles are formed when lava cools and drips down from the ceiling (just like water does).

Vicky looking as glamorous as always...

Temperate Climates

Cool Temperate Western Maritime Climates don't you just love 'em? Well if you don't then, unless you're planning on emigration, you need to get used to them.

So where are they found?

- Well between 40 and 60 degrees North/South constitutes a temperate climate
- And being on the Western edge of a continent constitutes a maritime climate
- What determines how far inland the climate extends is based upon the relief of the land

There are three types of rainfall: - Orographic Rainfall
                                                         - Convectional Rainfall
                                                         - Frontal Rainfall

So what other countries are remarkably lucky to share the same climate as the wondrous UK?

- South West New Zealand
- Chile, the Andes block the climate from extending any further within the country
- Canada, Vancouver - the Rockies block the climate from extending any further
- Western Europe, quite a few countries share our climate because the climate doesn't get blocked until the Alps

What does a Cool Temperate Western Maritime Climate mean?

- Weather is changeable with no marked seasonal differences
- Plenty of cloud and precipitation all year round
- Extremes of temperature are rare
- Low annual temperature range
- Fairly strong winds
- Warm summers
- Mild winters

- Maritime climates are unique as they are unusual to what we'd expect on similar lines of latitude. For example the UK are on a similar latitude to Moscow yet we experience a vastly different climate.
       - The reason for this is due to the high specific heat capacity of water. Water takes longer to heat up and cool down than land, this means that summers are cooler than expected and winters are milder.


Any questions?

Belfast

So to steal a small concept from Cryss

Number of exam results received today: 1
Number of results I was pissed off with: 1
Number of times I punched the wall: 15+

Clearly this blog didn't help me as much as I would have liked for the Belfast exam however the purpose of the blog wasn't purely to help me get higher grades but to hopefully help other people understand. So what I'd like to know is whether this blog is worth it, if it actually helps people understand and they find it useful then I'll carry on writing the blog. If people don't find it useful then I don't think there's much point in me carrying it on.

Basically if this blog is helping, speak now. If it's not then it'll probably disappear.

James

The Atmosphere

I am unbelievably bored, have nothing else to do and seeing as the blog hasn't been updated in a while I thought I'd explain the atmosphere in greater detail. They're in stratigraphical (is that a word?) order starting from sea level.

The Troposphere

Oh what a glorious place it is... This is the first layer of our atmosphere and it is heated via infrared radiation being radiated from the Earth, this means that as altitude increases temperature falls. Atmospheric pressure also decreases with altitude, there's a simple reason for this. The higher you go the less there is above you so the pressure decreases. Wind speeds increase with altitude in the troposphere as at higher altitudes there is less to act as a wind break.

Stratosphere

Once you get through the troposphere everything starts getting a bit warmer until temperatures reach a toasty -3 degrees Celsius. The reason the temperatures increase with altitude is because the stratosphere is heated by the absorption of  UV radiation by Ozone (so from above, not below).
When ozone absorbs UV it gets split up into Diatomic Oxygen and Atomic Oxygen, in the normal process this would then bond again to form Ozone. The ozone layer should remain in dynamic equilibrium (constantly changing, but overall staying the same), however when CFCs are emitted into the atmosphere they also get broken down. The Chlorine atom then bonds with an Atomic oxygen atom to form ClO preventing the atomic oxygen bonding with diatomic oxygen to replenish the ozone layer. So in reality CFCs don't destroy the ozone layer but rather prevent it from replenishing itself.

Mesosphere
Not much really goes on here to be fair, temperature decreases with altitude for reasons I can't accurately find out but I do know that the mesopause house the coldest temperature on Earth. The only other thing interesting to know is that the mesosphere is where most meteors burn up upon entering the atmosphere.

Thermosphere
I understand even less of this stratigraphical layer, for a confusing reason the temperature increases with altitude although not for the same reason as in the stratosphere. It's something to do with there being so few particles, I don't know google it.

Exosphere
There's like nothing here, at all. The number of particles (mainly hydrogen and helium) are so few that they can travel hundreds of kilometres without colliding with each other, this also means that the atmosphere stops behaving like a liquid. "Why are you even telling us this then?" You may be wondering... Well it sort of answers a question raised in class the other day about whether atoms in Space join Earth's atmosphere. It is actually the opposite, Earth experiences a net loss of hydrogen and helium at about 3 kg and 50 g respectively a second. That's a relatively tiny amount though so don't start worrying that we're running out of atmosphere.

The human race will have likely imploded before we ever lose our atmosphere.