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Overpopulation
- Overpopulation occurs when the number of ppl in a region is greater than the ability of land to support them.
- The Sahel is an overpopulated region in Africa that lies below the Sahara desert and above the equitorial forests
- Climate change has been one of the causes of this. Droughts have occured atot over the past 30 years limiting food production.·
- The population of the region is rising and most countries here are in stage 2 of the population cycle. Sudan has a birth rateor 39 per 1000 and a death rate of 10 per 1000.·
- Migration into certain areas has meant that the resources mustbe spread over a larger scale. In Sudan 30% ot the population live on 7% ofthe land.·
- War in the region has caused food resources and lives to be destroyed. In Darfur, a region the same size as France, almost every farming village has been attacked and burned
- Overgrazing and overcullivation by farmers has depleated soilfertility and made it less production — meaning less food.
- The main effect of overpopulation in the region has been desertification. The Sahara Desert is spreading south at a rate of l0km per year.
- Sudan will have to double it‘s food production to feed it‘s population in the future which seems impossible given there souces st presant.
- The Aral Sea is an overpopulated region in central Asia around Uzbekistan
- The people of this region used to thrive on the fishing industry .The Aral Sea was the 4th largest freswater lake in the world.
- During the 1960's, however, the Soviet Union decided to divert the seas 2 main rivers, the Arnu ond the Syr, to irrigate rice,melon and cotten fields.
- Evapouration took place on a large scale and the lake fell in size dramatically, lt also turned from a freswater lake into a salt water lake.·
- Another effect of the Soviet unions decision was that the industry, which was the main source of emploment and food,was destroyed and this is how the region became overpopulated
- Huge out-migrotion and brain-drain took place leaving an uneducated population behind with a lack of food
- In the l990's the Uzbekistan Government, along with others,put laws in place restricting water use in the region to aminimum in a hope to redevetope the area.
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Impact of EU Expansion on Ireland's econoomy
- The EU accounts for 40% of all trade in goods and services worldwide.
- Ireland became part of this when it joined in 1973.
- Back then, Ireland was at net beneficiary which meant we got significant financial funds to help us develop our country, e.g. (CAP or CFP or ERDF).
- As the 10 new states have joined the EU, Ireland has become a nett contributor. The funds we received are now aimed at developing the economies of the newer states, such as Poland.
- We will face increased competition for mobile investment. This is due to the newer countries having cheaper labour, low inflation and low tax rates, making it cheaper tbr MNC's to locate there rather than in Ireland.
- As we can see, many companies that have 'lower value' jobs have already begun to move away from Ireland to eastern periphery countries.
- Ireland will need to fight this competition and make the country more lucrative for MNC's by maybe providing tax breaks for example. For instance, labour costs in Poland average at €2 per hour but in Ireland they average €l7.50
- However, EU expansion does have positive effects on our economy. The new enlarged market will have an extra 75million people, bringing the EU population to over 450million, resulting in new prospects for Irish exports.
- Ireland needs to begin forging business links with the new member states like what AIB have already begun in Poland.
- There is a huge new market out there and Ireland needs to exploit that soon before other countries do.
- Ireland is retaining its policy of allowing anyone in the EU to come and work in the country. This means companies will have more choice when it comes to choosing workers, with different skills and language abilities, requiring companies to adoptto the changes.
- The new 10 countries will put a lot of strain on the CAP, as about 28% of the workforce are dependant on agriculture.
- Ireland's current income from the CAP will significantly drop due to the expansion. This could have serious implications on agricultural activities in Ireland, with many small farrners in the west of Ireland depending on EU funding to survive.
- Also, as structural funds will be focused on the underdevelped countires, Ireland's Funding will be reduced.
- lt is predicted that by 2007. lreland's Structural Fund income will fall from €987 million in 2003 to €44.5 million in 2007
- This will result in less funds being made available to go towards the development of the west of Ireland.
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Sheild Cones
- Formed and shaped by the actions of basic lava
- Basic lava: low in silica (50%} therefore fluid & fast
- Escaping gases 'push` lava forwards - travels long distances
- Lava is therefore spread long & thin — cooling to create a long, ‘gentle' slope
- Shield volcanoes = less violent {low in silica)
- Ex: Mt Vesuvius
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Dome Cones
- Formed and shaped by actions of acid lava
- Acid lava: high in silica (70%}therefore slow & thick
- Thick flow = travels short distance
- Lava & ash build up in layers-- forming steep mt sides
- Dome volcanoes a very violent and explosive (high in silica)
- Ex: Mt Saint Helen
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Explain how the study of plate tectonics has helped us to understand the global distrubution of volcanoes
- The global distribution of volcanoes is directly influenced by the actions of moving plates(plate tectonics).
- Volcanoes can be found across both constructive (separating) and destructive (colliding) plate boundaries.
- Volcanoes can also be located at ‘hot spots’ which occur in the middle of plates. In all three locations, it is the actions of moving convection currents in the mantle (asthenosphere) that contribute to the formation of volcanoes across the world.
- Constructive Boundaries
- Constructive boundaries involve the separation of tectonic plates. The separation of two oceanic plates such as the N.Ameriean and Eurasian plates, leads to the formation of volcanic islands.
- Convection currents in the mantle drive both plates in opposite directions — creating a Rift valley on the ocean floor.
- Magma is forced upwards from the mantle; cooling and hardening into solid rock on the sea floor.
- As magma continues to cool and accumulate, large under sea volcanic mts form along the edges of the rift vallay.
- Mid Atlantic Ridge is an example of such a feature.
- As magma continues to pour and harden, volcanic islands such as Iceland are finally formed on the ocean surface.
- Destructive Boundaries
- Volcanoes can also form when plates collide at destructive boundaries. When an oceanic and continental plate collide; the heavier oceanic plate sinks beneath the lighter continental plate in a process of subduction.
- The oceanic plate is absorbed into the mantle where it is melted and destroyed.
- The rising, melted magma is acidic and high in silica.
- As it breaks through the crust, it forms a steep-sided and highly explosive surface volcano such as Mt Saint Helen(N.America).
- During an oceanic-oceanic plate collision, the subducted ocean plate causes magma to rise — cool - harden on the sea floor.
- Overtime, a chain of volcanic islands form on the ocean surface. The Volcanic Island Arcs of Japan are an example of this feature.
- The curved shapes of the islands are a result of the subduction zone deep beneath the ocean crust.
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How is Limestone formed?
- Irish limestone formed in warm, shallow seas 350 million year ago
- Over thousands of years, shells and fossils build up along the sea floor
- Dead fossils and shells contained mineral: calcium carbonate
- Sediments compressed together under the growing weight on the sea bed.
- The loose sediments now ‘cemented’ together into solid rock
- This process is called lithification
- Limestone is a ‘layered’ rock — made up of horizontal rock layers called stratas
- Limestone is a permeable rock — water can pass through the many cracks & joinzs.
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The Limestone (Karst) Landscape
- Limestone rock creates a distinctive Karst Landscape - bare and stony.·
- Limestone rock is easily dissolved by water- creating many unique features above & below the surface.
- The Burren in Co. Clare is a distinctive Karst Landscape
- Karst Landscape is formed by the process of carbonation.
- Rainwater absorbs C02 from the air and forms a weak carbonic acid
- Rain's carbonic acid chemically reacts with the calcium carbonate in the limestone.
- Limestone is converted to calcium bicarbonate - a soluble (watery) form --washed away by rainwater.
- Carbonation continues to erode and deepen the cracks & joints in the limestone rock.
- Limestone pavements form.
- Large. flat slabs of rock (clints) are separated by deep eroded grooves called grikes.
- Continued carbonation creates deep openings in the rock called swallow holes
- Limestone rock can also be chemically weathered underground.
- Underground carbonation forms: caves, stalagmites, stalagtites & pillars
- Ex: Ailwee Caves. Co. Clare.
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Examine how humans interact with the rock cycle
- What is Mining?
- The extraction of valuable minerals from the earth
- Extraction of the earth`s non-renewable resources.
- Precious metals — gold, uranium. Useful minerals, metals & iron. Fuels - coal, oil, gas.
- 1 Mineral formation
- Rocks from which minerals are mined — ores. Ores = igneous & sedimentary rock types.
- Metals are created as a result of volcanic (hydrothermal) activity:
- Mineral-rich water passes through cracks/fissures within the earth’s crust — cooling & accumulating over time.
- Minerals collect and gather in cracks; creating metal-rich ‘veins’ in the rock.
- Ex: zinc. copper, lead 'vein’ deposits.
- 2 Mining Extraction
- ln the mining operation, humans interact with the rock cycle by extracting metals and fuels from ore.
- Mining in Ireland: 6000 employed. €1 billion generated for Irish economy.
- Humrm Interaction: Tara Lead & Zinc Mine, Co. Meath.
- Largest L & Z Mine in Europe. 680 employed. 100 million generated for local economy.
- 60% of lead -- used in batteries. Other uses; x-ray gown. Plumbing equipment.
- Zinc: galvanise metals from rust. Cosmetics. Paints. Extraction:
- `Stope and Pillar' method used.
- Large underground tunnels are blasted — stopes.
- Columns of rock left; in between the tunnels for support - pillars.
- Remote-controlled machinery crush ore (rock) and transport it to the surface for chemical treatment.
- Rock is crushed down to a powder - chemicals used to extract zinc and lead from the rock.
- Lead & Zine is tiltered out to form metal concentrate.
- Transported by rail to Dublin Port - Europe = smelted into pure and zinc.
- Waste water from the mine pumped to settling pond where it is neutralised with lime.
- Water is now cleaned and circulated back to the mine for reuse.
- The waste rock is mixed with cement and re-used to fill the empty mining tunnels(stopes).
- 3 Positive Environmental Factor
- Tara Mines is closely monitored by the Environmental Protection Agency.
- 1997: Two wetlands successfully constructed to treat waste (metal) water.
- 49 hectares (previously a settling pond site) has been renamed as uncontaminated grassland.
- Extensively landscaped to reduce visual impact of the mine.
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With the aid of a labelled diagram, examine the process that has led to the formation of any one Irish landform of your choice
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