Physical Geography Exam Answers

Notes

● Make sure to have all equipment: pens, pencils, rubbers, ruler, string etc.

● Carefully read each question so you know what is being asked. ● Always indicate what question you are answering. ● All diagrams should be drawn in a box and labelled. ● SRP= Single Relative Point ● Give answers in bullet point or paragraph form. Numbered points

below are just to show there are enough points for every answer.

Discuss the theory of plate tectonics (the plate tectonics model).

(30 marks=15 SRP’s) Came up in 2019

1. The theory of plate tectonics provides us with a model to describe the internal workings of the earth and explains why earthquakes, volcanoes, faults and fold mountains occur around the world.

2. Plate tectonics theory is a combination of 2 theories: Continental Drift Theory and Seafloor Spreading.

3. In 1912, a scientist named Alfred Wagner discovered the Continental Drift Theory.

4. He noticed that the coastlines of Africa and South America matched as if they once fitted as one.

5. He discovered exact matches between seams of rocks and fossils separated by thousands of miles of sea.

6. He said that all continents of the world once formed a single landmass which he called Pangea.

7. About 200 million years ago this landmass began to break up and eventually formed the landmasses we see today and will continue to drift around the earth.

8. At first most experts rejected the theory of continental drift as he could not explain how the plates moved.

9. In 1948, the Mid-Atlantic Ridge was discovered which showed a mountain range running under the sea along the Atlantic Ocean.

10.Similar mid-ocean ridges were discovered on the floor of the Pacific and other oceans.

11. In the 1960s, a geologist named Harry Hess studied the ages of rocks on the seabed of the Atlantic Ocean.

12. He discovered that rocks got older as they gradually moved away from the ridge. 13.This discovery suggested that the seafloor was getting wider and wider pushing

the continents apart. 14.Harry Hess’s theory of seafloor spreading supports Wegener's theory of

continental drift. 15. Diagram of one or both theories.

Examine how the tectonic cycle helps to explain the global distribution of one of the following: volcano, earthquake, fold mountain (30marks= 15 SRP’s) Last came up in 2017 1. Most of the world’s great volcanoes occur at destructive plate boundaries. 2. Crustal plates converge at such boundaries, for example near the coast of South

America where the Nazca and South American plates collide. 3. Subduction takes place here; the denser Nazca plate is pushed under the lighter

South American plate. 4. As the subducted plate descends into the upper mantle it reaches temperatures

of more than 1000°C. 5. It then begins to melt and form magma. This molten magma begins to force its

way upward towards the earth’s surface. 6. It often accumulates in huge underground masses or magma chambers called

batholiths. 7. The magma is contained here before erupting to the surface through holes called

vents or pipes. 8. These eruptions are usually violent because the vents through which the magma

erupts are usually quite small. 9. Another reason is because the magma usually contains explosive, superheated

steam and gases. 10.Once the magma reaches the earth’s surface the gases escape and it becomes

known as lava. 11.Layers upon layers of lava gradually build up to form cone-shaped mountains.

These mountains are usually steep-sided because the lava cannot run far from the mouth of the vent.

12.A great deal of volcanic activity also happens at constructive plate boundaries. 13.Crustal plates separate from each other for example, beneath the middle of the

Atlantic Ocean.

14.Where plates separate magma emerges from the earth’s mantle through long fissures (cracks) in the earth’s crust.

15.

Volcanic Activity Examine the influence of volcanic activity on the development of the

Irish landscape with reference to each of the following: Intrusive features & Extrusive

features. (30 marks= 15 SRP’s) Last came up in 2017

External features:

1. Plateaus, for example the Antrim Plateau in Northern Ireland.

2.The plateau covers a large part of Co. Antrim in Northern Ireland and was caused by volcanic activity 65 million years ago.

3. At the time, Eurasian and American plates began to split apart. As this happened, huge cracks called fissures appeared on the earth’s crust and magma from the earth’s mantle began to quickly emerge.

4. The runny basic magma spread out quickly to cover the chalk of the surface that existed in the area.

5.Several different lava flows- some of them up to 40 metres thick occurred over a period of 15 million years.

6. As each layer cooled and hardened into a layer of basalt rock. Eventually this formed the Antrim Plateau.

7. Other external features include volcanic cones, craters and calderas.

Internal features:

8. A batholith is a large mass of igneous rock which formed as magma pushed into the crust slowly over thousands of years and solidified.

9. The Leinster Batholith is the largest batholith in Britain and Ireland.

10. It stretches for about 120 kilometres from Co. Dublin to Co. Kilkenny.

11. The Leinster Batholith began 400 million years ago when the American and Eurasian plates collided.

12. This collision caused fold mountains to form in Leinster. It also caused parts of one plate to be subducted and pushed down into the earth’s mantle.

13. The Batholith cooled very slowly beneath the surface. As it did the hard-coarse rock called granite was formed.

14. Other internal features are sills, dykes, laccoliths and laccoliths.

Discuss the positive impact of volcanoes. (30marks=15 SRP’s) Last came up in 2018. 1. New land is sometimes created by volcanic activity. Examples include Hawaii and

Iceland. 2. These new islands can be a great physical and economic benefit to countries. 3. Volcanic rock breaks down quickly into fertile soils that favour crop growth and

food production. 4. The Mount Etna area in Sicily, for example is famous for olives as well as other

fruits and vegetables. 5. The volcanic Island of Java in Indonesia is so fertile that the rural population

density is one of the highest in the world. 6. In Brazil, volcanic rock is broken down into a reddish soil which is used to grow

coffee. 7. Valuable minerals can also be found in volcanic rocks. Such minerals include

gold, silver, diamonds and copper. 8. The presence of these minerals often give rise to prosperous mining activities. 9. Such mining activities creates employment and benefits the economy. 10.Some of the rocks that are mined, such as granite also provide excellent building

materials. 11.Some volcanic areas are excellent tourist attractions. Thousands of tourists flock

each year to see volcanic mountains such as Vesuvius as well as the town of Pompeii.

12.Volcanic activity also gives rise to hot springs and geysers which stimulate tourism.

13.Hot springs provide health spas and naturally heated pools in southern Italy. 14. A geyser called old faithful attracts millions of visitors each year to Yellowstone

Park. 15.Volcanoes are also used for geothermal energy. Iceland uses geothermal energy

to provide central heating to many towns.

Explain how the occurrence of seismic activity can be predicted and its effects reduced (30marks= 15 SRP’s) Last came up in 2017 1. It is relatively easy to predict where serious earthquakes are likely to occur. They

almost all happen on fault lines. 2. It is almost impossible to predict precisely when an earthquake will occur, but

methods have been put in place to try and solve this problem. 3. Seismographs are used to record vibrations in the earth’s crust. Such vibrations

may be shocks that occur before the main tremors of an earthquake. 4. By looking at patterns of seismograph activity to see which areas might be

affected next could help predict an earthquake. 5. By studying the history of earthquakes in a certain area, scientist try to discover a

pattern in the seismic gaps between earthquakes 6. The land sometimes bulges or tilts before a major earthquake. By measuring the

land with lasers to see if it is moving, this could indicate an earthquake is about to occur.

7. If levels of oil or water in wells begin to rise this is a sign that the ground is under pressure and that an earthquake could be about to occur.

8. Animal behaviour can also indicate that an earthquake is about to occur. There have been reports of snakes coming out of hibernation and farm animals refusing to enter a building before an earthquake struck.

9. In more recent times, scientists have measured electromagnetic signals coming from the ground in areas that experience earthquakes and corresponding changes to atmosphere above to try and predict earthquakes.

10.The effects of earthquakes can be reduced by introducing strict planning laws to prevent buildings being located near fault lines e.g. California, USA.

11.Measures can also be taken to make buildings earthquake-proof. Countries such as Japan and the USA have introduced such measures.

12.By putting in very deep foundations with rubber layers, these act like shock absorbers which reduce the chances of a building collapsing.

13.Some countries have earthquake drills in schools and businesses to help reduce injury and deaths.

14.Another way to reduce injuries and deaths would be to have earthquake shelters/zones for people to go to in an emergency.

15.Another way to reduce the impact of an earthquake is by having high sea walls by the coast. If a tsunami occurs after an earthquake, these high walls can reduce the damage caused by large waves.

Explain the formation of each of the following, with reference to examples that you have studied: One sedimentary rock & One metamorphic rock. (30 marks) last came up in 2019

1. Sedimentary rocks are formed from the sediments of other rocks or of plants and

animals. These sediments were first broken down by forces of weathering and erosion.

2. There are two types of sedimentary rocks: organic and inorganic. 3. Organic sedimentary rock is formed from the remains of once living things. They

include limestone, which was formed from the remains of sea creatures and coal which formed from vegetation.

4. Inorganic sedimentary rocks are formed from sediments of other rocks. They include sandstone and shale. Sandstone is Ireland’s second most common rock and was formed about 400 million years ago.

5. Most of Ireland’s sandstone is old red sandstone and it formed when Ireland was located closer to the equator.

6. An example of sandstone can be found in the Mountains of Munster. 7. Limestone is Ireland’s most common rock and formed 350 million years ago

when Ireland lay below a tropical sea near the equator. 8. As countless generations of fish and other sea creatures died, their bones and

shells piled up on the seabed. With the help of mud, they were compressed by the weight and cemented by calcium until it formed solid limestone.

9. An example of limestone can be found in the Burren Co. Clare. 10.Metamorphism is the changing of rock by the action of great heat and /or great

pressure. The great heat is from when magma rises underground close and comes to rocks under the surface. The great pressure is caused by plate tectonics like plate collision and plate subduction.

11. The most common metamorphic rocks in Ireland are Black Marble in Co. Kilkenny and quartzite at Croagh Patrick, Co. Mayo.

12. There are three types of metamorphism: thermal, dynamic and regional. 13.Thermal Metamorphism happens when great heat from rising magma inside the

earth’s crust comes into close contact with rocks. The magma bakes and causes recrystallization of the minerals in the rock.

14. Dynamic Metamorphism happens where rocks are changed by great pressure at fault lines or at the edge of colliding plates.

15. Regional Metamorphism This happens when rocks are exposed to both great heat & pressure by magma and plate tectonics.

Explain the formation of igneous rocks with reference to examples that you have studied. (30 marks= 15 SRP’s) Last came up in 2014

1. Igneous rocks are formed from magma that cools and solidifies either below or on the earth’s surface.

2. Basalt and Granite are igneous rocks made from magma. These rocks begin the rock cycle.

3. Basalt is an extrusive rock. When magma (lava) cools and hardens on the surface of the ground it’s called Basalt.

4. When basic magma (that contains less than 55% silica) rises out of the crust, through a hotspot, volcano or the Mid-Atlantic Ridge it cools and solidifies.

5. Water, waves and air harden the lava very fast. It hardens so fast that large crystals do not form. - only contains microscopic crystals

6. Basalt is a dark black hard rock. It is not eroded or weathered easily. In Ireland basalt is found at the Giants Causeway, Antrim.

7. It was made here over 60 million years ago. It is a hexagon shape and is grouped into columns. It’s also seen in Iceland and on the seafloor of the Atlantic at the Mid –Atlantic ridge.

8. Today, Basalt is used for gravel to build roads and motorways. 9. Granite is the most common of the intrusive rocks and it underlies most of the

continents. It’s also called Intrusive because it's formed when magma cools and hardens very slowly below the earth’s surface.

10.Granite is formed at subduction zones, and destructive plate boundaries for example the Nazca and South American plate boundary.

11.As the oceanic plate sinks into the mantle it melts, and it is recycled into magma. The magma then rises into the crust but it does not reach the surface. The magma cools slowly several kms below the surface.

12.Magma cools so slowly that large crystals of feldspar, mica and quartz form in the magma. In Ireland, Granite formed 400 million years ago during the Caledonian folding.

13. It formed a Batholith - large domed masses of granite. Granite also forms Dykes and Sills. Sills are made when Magma cools horizontally along bedding planes and Dykes are made when magma cools vertically.

14. It’s a hard, rough, multi-coloured rock, – grey, white and black. It looks like a fire lighter. It is not eroded or chemically weathered easily.

15. It is found in the Wicklow and Dublin Mountains. It is often used to make kitchen counters and gravestones.

Humans interact with the rock cycle in a number of ways. Describe and explain how this interaction with the rock cycle takes place, with reference to one of the following: Mining, Extracting building materials, Oil/gas exploitation, Geothermal energy production. (30 marks= 15 SRP’s) last came up in 2018

Extracting building materials

1. Quarrying can be described generally as the extraction of rock from large, man-made cavities on the earth’s surface.

2. The Roadstone Wood Group quarry at Belgard in Dublin is one of the largest limestone quarries in Europe.

3. It produces more than 2 million tonnes of crushed limestone every year. 4. It also converts its quarried rock into building products such as asphalt, concrete

and concrete blocks. 5. There are 5 main processes that take place. The first is extracting the stone. This

is done by removing the topsoil and blasting the rock face. 6. Some controlled sequence blasts can remove up to 60,000 tonnes of rock. 7. The next process is called ‘crushing the aggregates. The loose rock is collected

by a huge loading shovel that can scoop 20 tonnes at a time. 8. These are carried by dump trucks to the primary crusher which starts to break

down the rock. Second stage crushers break the rocks down further to make smaller rocks.

9. The third process is the asphalt plant. A conveyor belt carries selected aggregates here where they are heated at up to 180° and mixed with bitumen to make tarmac.

10.The fourth process is the concrete plant. Here, aggregates are mixed with sand, cement and water to make concrete.

11.Chutes are used to load the concrete onto lorries which are then transported to customers or markets.

12.The final process is the concrete block plant. Here, aggregates are mixed with water and cement before being filled into mould boxes.

13.The concrete blocks are vibrated within their moulds until they are compacted and solid.

14.They are then transferred to curing chambers where they are kept to dry out and harden for 24 hours.

15.Finished concrete blocks are stacked into cubes, which are wrapped and strapped ready for sale.

Explain one process of physical weathering and one process of chemical weathering. (30marks=15 SRP’s) Last came up in 2016

1. Mechanical weathering is the physical breakdown of rocks. One example of this type of weathering is freeze-thaw action.

2. Freeze-thaw action occurs when rocks are broken up by frost action. Happens due to high moisture levels (rain, snow) and freezing night-time temperatures

3. It usually occurs in steep land and or mountainous areas e.g. Sugarloaf Mountain, Co. Wicklow.

4. During the day water gathers in cracks in the rocks. At night the water freezes and expands by 10%.

5. Over time these processes weaken the rock and it eventually forces a piece to break off and fall as screen. They often form heaps at the bottom of slopes.

6. Frost shattering is common during winter months in Irish mountains such as the Mcgillycuddy Reeks in Co. Kerry.

7.

8. Chemical weathering is when rocks are dissolved because of a chemical reaction.

9. As rain forms it takes in carbon dioxide from the atmosphere. This makes a weak carbonic acid which has a huge effect on Limestone. 10. Carbonation occurs in areas where bare limestone is exposed to the weather. This is known as a karst landscape. 11. An example would be the Burren Co. Clare. 12. Carbonation leads to the development of limestone pavements, swallow holes, caves, stalactites, stalagmites and pillars. 13. A limestone pavement is a gently sloping expanse of bare limestone consisting of blocks (clints) separated by fissures (grikes). 14. As rivers flow underground through swallow holes carbonation enlarges the passage which makes caves. 15. Carbonation is very common in Ireland, which has a rainy climate and contains a huge amount of limestone.

Describe and explain the factors governing the operation of one mass movement process that you have studied. (30 marks=15 SRP’s) last came up in 2019 1. Mass movement occurs when regolith moves down slopes under the influence of

gravity. 2. There are six factors that affect mass movement. They are slope, water, slope

material, vegetation, human activities and tectonic activity. 3. Slope- as the slope increases, so does the likelihood and the speed of mass

movement. 4. Water- assists mass movement because it lubricates regolith and makes it heavy. 5. Vegetation- plant roots help to bind regolith together and so reduce mass

movement. The absence of vegetation increases the likelihood of mass movement.

6. Human activity- people increase the likelihood of mass movement when they clear away vegetation or cut into hillsides to construct roads or buildings.

7. Tectonic activity- earthquakes or volcanic eruptions can trigger mass movement. 8. One type of mass movement is a landslide which are sometimes called debris

avalanches. 9. They are very fast movements of usually dry soil and rock down very steep

slopes. 10.Landslides often happen where the frost action weathers and loosens rock on a

slope. 11.This creates a regolith that tumbles or rolls downward on a slope. 12.Landslides may happen where people dig into the side of slopes for quarrying or

construction purposes. 13.Landslides also occur at sea cliffs, where a wave has undercut the slope. 14. In 2016, Galway, Ireland experienced a landslide that saw 4,000 tonnes of bog

collapse onto the N59 road. 15. In 1933, a landslide in Deixi, China killed all but one of the 577 people living in

the town.

*Diagram can also gain marks

Examine the impact of the processes of erosion on the formation of one fluvial landform, coastal landform or glacial landform that you have studied

(30 marks=15 SRP’s) Asked differently in 2019, this exact question came up in 2017.

1. An Irish landform that I have studied is a waterfall. 2. A waterfall is a sudden sharp drop in the riverbed causing the river to drop over

the edge of hard rock. 3. An Irish example is Torc Waterfall, Kerry. Another example is Niagara Falls which

borders the USA and Canada 4. A waterfall is found in the young stage of a river. It is formed where the riverbed

is gently sloping. 5. A waterfall is formed where the river runs along a riverbed of hard rock and soft

rock (like Limestone). 6. The river’s rapids erode the soft rock at a faster rate than the hard rock. This is

called differential erosion. 7. Hydraulic action is the erosion caused by the force of moving water. It loosens

and erodes the soft rock downwards in the riverbed. 8. Abrasion, where the river’s load erodes the banks and riverbed, erodes the

riverbed downwards. This causes vertical erosion. In heavy rain, this rate of erosion is greater

9. Over time, vertical erosion of the bed forms a steep slope in the bed. Then the edge of the hard rock forms an overhang.

10.A plunge pool forms at the point where the falling water off the overhang hits the soft rock below.

11.Eddying, the swirling motion of the water, causes the river’s loads to move in circular motion, eroding the plunge pool. The plunge pool deepens.

12.The power of the falling water causes turbulence in the plunge pool. Solution erodes the soft rock under the overhang. This leads to the undercutting of the face of the waterfall.

13.With time, the overhang becomes unstable and eventually it will collapse into the river. This is called headward erosion.

14.The waterfall retreats backwards moving upstream. A gorge is formed at both banks of the river in front of the waterfall.

Examine the impact of the processes of deposition on the formation of one fluvial landform, coastal landform or glacial landform that you have studied

(30 marks=15 SRP’s) Last came up in 2019

1. An oxbow lake is a feature of river deposition found in the old stage of a river. 2. It is a horseshoe-shaped lake that was formerly part of a meander. 3. As a meander develops, erosion continues the outside of the bends and

deposition builds up on the inside of the bends. 4. The neck of land between the outside bends of the meander becomes narrower

due to this erosion. 5. Three types of erosion occur on an oxbow lake: hydraulic action, abrasion,

attrition and cavitation. 6. Hydraulic action- the power of the rapidly moving water loosens and dislodges 7. Abrasion- the load carried by the river hits and erodes the riverbed. 8. Cavitation- bubbles of air burst and emit tiny shock waves that can loosen

fragments of clay or sand from the banks 9. Continued bank caving on the outer riverbank causes the meander to become

more and more pronounced. 10.As the neck becomes increasingly narrow flooding can result in the river breaking

through this neck of land. This results in the creation of a new river course, bypassing the former meander.

11.The river has little energy in its old stage, and so deposition of alluvium builds up and cuts off the former meander from the course of the river, thus creating an oxbow lake.

12.Because the oxbow lake is not being supplied with river water, it will eventually dry up over time.

13.This can result from evaporation or from the lake being filled with silt from flood water

14.Examples of oxbow lakes can be found in the old stages of the Mississippi River and the River Moy, Co. Mayo

15.

Examine the impact of the processes of erosion on the formation of one fluvial landform, coastal landform or glacial landform that you have studied.

(30 marks=15 SRP’s) Asked differently in 2019, this exact question came up in 2017.

1. A sea cliff is a vertical or almost vertical section of the coastline that has been formed by sea erosion.

2. An example would be The Cliffs of Moher in Co. Clare. 3. Three processes of erosion that occur here are hydraulic action, abrasion, and air

compression. 4. Hydraulic action is erosion by the power of water as the sea waves pound against

the coast. 5. Destructive waves are particularly powerful, especially during storms. They can

exert up to 25 tonnes of pressure on the cliff. 6. Abrasion is erosion by stones, pebbles and sand being hurled against the coast

by the waves. 7. Air compression happens when oncoming waves trap air in the cracks in the cliff.

This repeated process eventually causes rocks to shatter. 8. These processes first erode a notch in the coast between high-tide level and

low-tide level. 9. As the notch grows gradually deeper, the sea increasingly undercuts the coast. 10.The unsupported rock above eventually collapses, when this happens a cliff is

formed. 11.The waves then erode a new notch which causes another collapse of the

overhang which forces the cliff to retreat. 12.As a cliff retreats the rocks that were at its base are exposed and form an almost

flat surface that is uncovered at low tide. 13.This flat surface is called a wave-cut platform. 14.As a wave -cut platform grows wider, it helps to break the power of oncoming

waves before they reach the cliff. 15.

Examine the impact of the processes of deposition on the formation of one fluvial landform, coastal landform or glacial landform that you have studied

(30 marks=15 SRP’s) Last came up in 2019

1. A beach is a feature of deposition that is an accumulation of materials on the seashore between high tide and low tide levels.

2. An example of a beach is Dollymount in Co. Dublin. 3. An ideal beach would be slightly concave in profile. Its backshore is slightly

steeper than its foreshore. 4. Most straight beaches are formed by constructive waves on gently sloping

shores. 5. The powerful swash carries materials up the wide shore. The waves spread out

over the shore, so that much of the water soaks into the sand. 6. The backwash of each wave is smaller and weaker than the swash. This causes

materials to be deposited on, rather than removed from the shore. 7. Powerful swashes have enough energy to push larger stones and pebbles to the

top of the beach. 8. As a result, larger beach materials tend to be concentrated at the top of the

beach while finer materials tend to be concentrated on the foreshore. 9. Longshore drift also contributes to the formation of beaches. Pebbles and sand

carried along a shore by longshore drift will be deposited where waves lose energy.

10.Many beaches in the West of Ireland are ‘pocket beaches’ that occupy small bays. They are formed mainly by wave refraction.

11.As incoming waves refract or bend around the headlands, their power is concentrated around the headlands and spread out or dissipated in the bays.

12.The reduced energy of such dissipated waves causes the beach material to be deposited in the bays.

13.Ridges and runnels are gently sloping ridges that can be found along the foreshore of some sandy beaches.

14.A storm beach is a steep ridge of stones and gravel that exists at the back of the beach. An example is Bray, Co. Wicklow.

15.

Examine this statement with reference to one of the following:

The impact of human activity on river processes

The impact of human activity on coastal processes (30marks=15 SRP’s)

The impact of human activity on mass movement Last came up in 2019

1. The River Rhône Project in France is an example of human activity on river processes.

2. In 1921, the French government set up a special body to control the River Rhône and to promote economic development in its basin.

3. This body was called Compagnie Nationale du Rhône (CNR). 4. Its main aims were to control flooding, improve navigation, hydroelectric power

and to use irrigation to improve agriculture.

Flood control

5. More than 20 dams were built on the Rhône and its tributaries.

6.The dams and the artificial lakes behind them are used to regulate river flow. They store water during periods of ice-melt and release it during dry summers.

7.This has put an end to the flooding that has previously devastated farmlands and low-lying cities.

Navigation

8. Several diversion canals were built along the Rhône. They allow barge traffic to bypass narrow gorges that previously hindered river navigation.

9. The CNR’s flood control measures also assist navigation as they assure river levels are regulated and adequate throughout the year.

10.Barges of up to 5,000 tonnes can carry bulky goods from Lyon to Sete.

Hydroelectric Power

11. Hydroelectric power stations were built on many dam sites which converted the river into a major source of power.

12.Cheap electricity has been used to attract industries that need lots of energy for their manufacturing processes.

Irrigation and Agriculture

13. The artificial lakes and reservoirs provide water to irrigate agricultural land which had previously been affected by drought during the summer.

14. Rural prosperity increased greatly because of the project and crops such as rice, apples, peaches and vegetables began to flourish.

15. Farm related spin-off industries began to develop in towns such as Nimes and Montpellier where food processing and the manufacture of fertilisers began to prosper.