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AS Geography

Tommy Chadwick Inglés 115 fichas

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1What is a Cold Environment?-Cold Environments are Icy Landscapes which occur in High Latitudes and High mountain areas.
-Abundance of snow and ice with little vegetation
-Sparsely Populated
2Examples of Maritime Cold EnvironmentsArctic and Southern Oceans.
Much of Arctic ocean is covered by floating ice.
Southern Ocean is rich in Animal life and has a high level of Biological productivity despite being so cold.
3What is a Glacial Environment?Areas covered by ice sheets and glaciers. The largest of these is the continent of Antarctica and its surrounding ice shelves
4What is a Periglacial area?A Periglacial area or 'Tundra' exist in dry high latitude areas which are not permanently covered by snow and ice.
-Places such as Northern Alaska, Canada, Northern Scandinavia.
-Cold Conditions create permanently frozen ground known as permafrost.
5What is an Alpine region?Alpine regions occur in Asia (Himalayas, Tibet Plateau), Europe (Alps, Norwegian Mountains) Australasia (Southern Alps in New Zealand) and Americas (Rockies, Cascades, Andes)
These areas contain small ice caps, mountain glaciers and tundra environments.
6What is a Glacial Budget?A Glacial Budget is where ice recedes or accumulates depending on the balance between Accumulation and Ablation
7Two Types of glacier, and difference between them?Temperate- Melt in summer, releasing huge amounts of meltwater. Move by basal flow, extending and compressing flow, creep and surges.
Polar- occurs in areas where the temperature is permanently below 0'C and therefore no melting occurs.
8What is Compressional Flow?Where there is a reduction in the gradient of the valley floor leading to ice deceleration and a thickening of the ice mass. At such points erosion is at its maximum.
9What is Extending Flow?When the valley gradient becomes steeper. The ice accelerates and becomes thinner, leading tot reduced erosion.
10What is Basal Flow/Sliding?As the glacier moves over bedrock, there is friction. The lower ice is also under a great deal of pressure and this, combined with the friction, results in some melting. The resulting meltwater acts as a lubricant, enabling the ice to flow more rapidly.
11What is Internal Deformation?When ice crystals orientate themselves in the direction of the glaciers movement and slide past each other. As surface is moves faster, crevasses develop. Internal flow is the main feature of the flow of Polar glaciers as, without the presence of meltwater, they tend to be frozen to their beds.
12What is Rotational Flow?Occurs within a corrie/cirque, the birthplace of many glaciers. Here ice moving downhill can pivot about a point, producing a rotational movement. This, combined with increased pressure within the rock hollow, leads to greater erosion and an over-deepening of the corrie floor.
13What is Frost Shattering?Occurs in areas where temperatures rise during the day but drop below freezing at night for a substantial part of the winter. Water which enters cracks in the rocks freezes overnight. Ice occupies more space than water (10% more) and therefore exerts pressure on the crack. As the process continues, the crack widens, and eventually pieces of rock break off.
14What is Glacial Erosion?Glacial erosion tends to occur in upland regions and is carried out by two main processes:
Abrasion and Plucking
15What is Abrasion?Where material the glacier is carrying rubs away at the valley floor and sides. It can be likened to the effect of sandpaper or a giant file. The coarser material may leave scratches on the rock known as 'Striations'; the finer debris smoothes and polishes rock surfaces. The debris involved in abrasion is often worn down by the process into a very fine material known as ROCK FLOUR.
16What is Plucking?Involves the glacier freezing onto and into rock outcrops. As the ice moves forward, it pulls away masses of rock. Plucking is mainly found at the base of a glacier where pressure and friction often result in the melting of the ice. It is also marked in well-jointed rocks and in those where the surface has been weakened by freeze-thaw action (frost shattering). Plucking leaves behind a very jagged landscape.
17Describe a CorrieA Corrie is an armchair-shaped rock hollow, with a steep back wall and over-deepened basin with a rock lip. It often contains a small lake (tarn). In the British isles, Corries are mainly found on north, northeast-facing slopes where reduced isolation allows more accumulation of snow.
18What is an Arete?When two corries lie back to back or alongside each other, enlargement will often leave a narrow, steep sided ridge between the two hollows, called an Arete.
19How does a Pyramidal Peak form?If more than two corries develop on a mountain, the central mass will survive as a pyramidal peak, which often takes on a very sharp appearance due to frost shattering.
Eg- Matterhorn in the Alps
20What is a Glacial Trough?Glacial Troughs or Glaciated Valleys are long U-Shaped valleys carved out by a glacier.
-Fairly straight with wide base and steep sides
-Stepped long profile with alternating steps and rock basins
-Some end with heads at steep walls called: Trough End
-Filled with ribbon lakes
-Formation of Fjords
21Name the types of Moraine
22What is a drumlin?A drumlin is a rounded hill
-They are smooth, oval shaped hills, often resembling the top half of an egg
-As long as 1.5km and up to 50-60m high
-Elongated in the direction of ice advance
-Stoss is steep, Lee is gentle
Found in groups called swarms
23Fluvioglacial ErosionProglacial Lakes and Overflow Channels
Glacial meltwater has great erosive power because its voluma and the large amount of debris it contains.
SEE SEVERN FOR EXAMPLE
24Fluvioglacial depositionThe melting of ice produces a great deal of water which has the capacity to carry much debris. As the water often flows under considerable pressure, it has a high velocity and is very turbulent. It can therefore pick up and transport a larger amount of material than a normal river of similar size.
25What is an Esker?Eskers are believed to be deposits made by subglacial streams. The channel of the stream is restricted by ice walls, which creates hydrostatic pressure and allows the stream to flow uphill for some points.
The bed of the channel builds up, and a ridge is left behind when the glacier retreats.
26Features of an Esker-Long ridges of material running in the direction of ice advance.
-Sinuous(winding) form, 5-20m high
-Consist of sorted coarse material, usually coarse sands and gravel
-Often stratified
27What is a Kame?Kames are mounds of fluvioglacial material (sorted, and often stratified, coarse sands and gravel). They are deltaic deposits left when meltwater flows into a lake dammed up in front of the glacial snout by recessional moraine. When the ice retreats, the delta kame often collapses. Kame terraces are often found along the glacial valley sides
28What is an Outwash Plain?Outwash plains are found in front of the glaciers snout and are deposited by the meltwater streams issuing from the ice. They consist of material that was brought down by the glacier and then picked up, sorted and dropped by running water. The coarsest material travels the shortest distance and is therefore found near the glacier.
29What is a Periglacial Area?Periglacial areas are those which, although are not actually glaciated, are exposed to very cold conditions with intense frost action and the development of permanently frozen ground or permafrost. EG- Russia, Alaska, Northern Canada
30What is Permafrost?Permafrost occurs when subsoil temperatures remain below zero for at least 2 consecutive years. It is estimated that permafrost covers around a quarter of the Earths surface. There are three different types of permafrost.
CONTINUOUS, DISCONTINUOUS, SPORADIC
31Describe the three types of PermafrostContinuous- found in the coldest regions reaching deep into the surface layers- 1500m
Discontinuous- occurs in regions that are slightly warmer, where the ground is not frozen to such great depths. 20-30m
Sporadic- where mean annual temperatures are around or just below freezing point
32Frost HeaveAs the active layer starts to refreeze, ice crystals begin to develop. They increase the volume of soil and cause an upward expansion of the soil surface. Frost heave is most significant in fine-grained material and, as it is uneven, it forms small domes on the surface.
33What is Nivation?Nivation takes place beneath patches of snow in hollows, particularly on North and east facing slopes. Freeze thaw action and possible chemical weathering , operating under the snow, cause the underlying rock to disintegrate. As some of the snow melts in spring, the weathered particles are moved downslope by the meltwater and by solifluction. Over some period of time, this leads to the formation of nivation hollows, which when enlarged, can be the begginnings of a corrie.
34SolifluctionWhen the active layer thaws in summer, excessive lubrication reduces the friction between soil particles. Even on slopes as shallow as 2degrees, parts of the active layer then begin to move downslope. This leads to solifluction sheets or lobes
35What is an Ice Wedge?At temperatures below -15°C, the soil becomes so brittle that it cracks as it contracts in response to cold temperatures. Come spring, meltwater fills these cracks and subsequently freezes into what are referred to as ice wedges. Year after year, the cracks increase in depth and diameter, and so do the ice wedges.
36Patterned Ground
37Describe PingosPingos are dome shaped hills that are commonly 500m in diameter and 50m high
38Closed System PingosWater is trapped in small depressions during summer because the ground underneath is permanently frozen and effectively impermeable (won’t let water through it). Over winter, ground water underneath the lake sediments within the Talik (unfrozen ground) can be trapped by ice from the lake surface as the lake freezes, and advancing permafrost within the ground. This decrease in temperature causes this ground water to freeze into and ice lens, which grows over time as water freezes to the ice lens due to the increase in hydrostatic pressure. This causes the sediment above to bulge upward into the characteristic pingo shape.
39Open System PingosOpen system pingos occur in areas of discontinuous permafrost where there are interspersed areas of permafrost (land frozen for at least 2 years) and talik. The active layer continually freezes and melts year on year above the permafrost and talik. Over winter, as the active layer freezes down over water can become trapped between the descending freezing plane of the active layer and the permafrost that surrounds it. This promotes the growth of an ice lens which pushes the land up above it as it expands. Water underneath the permafrost can move through the talik between the permafrost areas because of capillary action (the movement of water through the soil because of ) and hydraulic pressure. This water migrates to the ice lens and freezes, swelling the ground above further.
40CASE STUDY OF EXPLOITATION OF TUNDRA AREASTRANS-ALASKAN PIPELINE
The Trans-alaskan pipeline goes from Prudhoe Bay in Northern Alaska to Valdez in the South. It cost $8billion to build and travels 800miles.
41What were the problems with this project?-Seas Frozen
-Air temperatures= -50
-Active layer thaws in summer
-Crosses Earthquake Belt
-Crosses Caribou Migration Route
-Underground Pipe may thaw ground
-Oilfield could only be reached by air
42How were they dealt with?-Pipeline was built to carry oil
-Pipes were well insulated
-Pipes placed on raised Stilts
-Sliding Shoes and Zig Zag shapes applied
-Raised pipes, caribou bridges
-Pipeline was raised on stilts with refrigerators
-Roads and highways built
43Who are the Vuntut Gwitchen, and how have their methods changed?The Vuntut Gwitchin are the people of Old Crow flats in Alaska, which were re-culturised by the Trans-alaskan pipeline.
U-shaped traps and arrows-->Rifles and Snowmobiles
Caribou for Hides and meat--> only traditional wear and some meats
44CASE STUDY OF EXPLOITATION IN SOUTHERN OCEANSKRILL FISHING
-Tiny Shrimp Like Creatures/Crustacions
-Measuring around 2.5 inches long and weigh 2 grams
-Spawn under the sea ice
-6,000,000 tonnes of Krill in the Southern Oceans
-Bottom of the food chain
45Why is Krill a valuable resource?-Used as fish oil
-Feed for Salmon Farms
-Very good for your body
-Support entire food chain in Antarctica
-Krill Oil supplies us with money as it is expensive.
46What are the risks to the environment from Krill fishing, and what attempts are being made to prevent this?-Krill fishing will effect the whole ecosystem
-Species will suffer as they are bottom of //////the food chain//////
-No fishing within 12 miles of islands: South Georgia
-Blue chip marine reserve around South Georgia
-Very few limitations
47What efforts are being made to make Krill Fishing Sustainable?Georgias economy is funded by Krill Fishing (£3 million p/year) and therefore it would be a disadvantage to make it a marine reserve
Limit amount of fish that is allowed to be brought in
48CASE STUDY OF EXPLOITATION IN SOUTHERN OCEANSTOURISM IN ANTARCTICA
People visit Antarctica for many reasons: There is a huge variety of wildlife to see, Scenery is beautiful, Climbing, Walking, Kayaking, Snowboarding and Skiing. However, this is effecting the environment of Antarctica
49How is this tourism effecting the environment of Antarctica?-Invasive species
-Impact on breeding birds
-Erosion or disturbance of fragile environments
-Oil spills from ships and boats
50How are these effect being handled?Restrictions on number of tourists allowed to visit. The Advantage of having limited visitors is that there is as little environmental impact as possible. Also, the trip is so expensive that it tends really to be that the only people visiting are the ones very passionate about Antarctica.
51Can tourism be handled sustainably?Tourism can be managed sustainably as the people that organise these tourist opportunities can manage tourism before problems occur.
52RIVERSRIVERS
53Describe the Drainage Basin Hydrological Cycle
54What is Water Balance?
55Factors Affecting River Discharge-Intensity/Duration of the storm
-Antecedent Rainfall
-Snow
-Rock Type
-Size and Shape of Drainage Basin
-Gradient
-Land Use- Urbanisation/Farmland
-Vegetation=Interception
56Read the Storm Hydrograph
57Rivers erode because they possess energy. Their total energy depends on..Weight of the water- Greater mass of water the more energy it has
Height of the river above sea level- source of potential energy
Steepness of Channel- Controls speed of river which determines kinetic energy
58What is Abrasion?(corrasion) is the scraping, scouring and rubbing action of materials carried along by a river (the load)
59Hydraulic ActionThe sheer power of moving water. Movement of loose unconsolidated material due to the frictional drag of the moving water on sediment lying on the bed.
60CorrosionMost active on rocks that include carbonates such as limestone and chalk. The minerals in the rock are dissolved by weak acids in the river water and carried away in solution.
61AttritionReduction in size of fragments and particles within a river due to the process described above. The fragments strike one another as well as the river bed. They therefore become smoother, smaller and more rounded as they move along the river channel.
62Vertical ErosionRiver is attempting to cut down to its base level , which is usually sea level. This is where the river cuts down into the valley mainly by abrasion and hydraulic action.
FOUND IN UPPER COURSE
63Lateral ErosionOccurs more frequently in the MIDDLE AND LOWER CLASS stretches of the river. Here the river possesses a great deal of energy
64Where does a river obtain its load from?-Material that has been washed, or has fallen, into the river from the valley sides
-Material that has been eroded by the river itself form the bed or banks
65Tractionlarge stones and boulders are rolled along the river bed by water moving downstream. This process only operates at times of high discharge.
66SaltationSmall stones bounce or leap-frog along the channel bed. This process is associated with relatively high energy conditions.
67SuspensionVery small particles of sand and silt are carried along by the flow of the river. Such material is not only carried but is also picked up, mainly through the turbulence that exists within the water.
68SolutionDissolved minerals are transported within the mass of the moving water
69What is the Capacity of a river?The capacity of a river is a measure of the amount of material it can carry, that is, the total volume of load.
70What is the River Competence?The competence of a river is the diameter of the largest particle that it can carry for a given velocity.
71What is the Hjulstrom Curve?The Hjulstrom curve shows the relationship between the velocity of a river and the size of particles that can be eroded, transported or deposited.
72Example of the Hjulstrom Curve
73Describe the cross profile of the upper course of a river
74Middle Course
75Lower Course
76What is the Graded ProfileThe graded river is when the river has used up all of its energy in the movement of water and sediment so that no free energy is left to undertake further erosion. A graded profile is concave and smooth. Stream's maintain their grade through a balance between erosion, transportation, and deposition.
77Define Potential and Kinetic EnergyPotential energy (or stored energy) is fixed by altitude of the source of the stream in relation to base level.
Kinetic energy (or energy due to movement) is generated by the flow of the river which converts potential energy into moving energy.
78What is a Wetted Perimeter?The wetted perimeter is the total length of the river bed and banks in cross section that are in contact with the water in the channel
79What is the Hydraulic Radius?The hydraulic radius is the cross sectional area / wetted perimeter. It is a measure of efficiency. A high HR means that the river is more efficient. This is because there is a smaller proportion of water in contact with the wetted perimeter so friction is lower which increases velocity
80What does a high hydraulic radius mean?A high hydraulic radius means that the river is efficient. This is because the moving water loses proportionately less energy in overcoming friction when the ratio between cross sectional area and wetted perimeter is low.
81What is a Pothole?Potholes are cylindrical holes drilled into the rocky bed of a river by turbulent high-velocity water loaded with pebbles. The pebbles become trapped in slight hollows and vertical eddies in the water are strong enough to allow the sediment to grind a hole into the rock by abrasion (corrasion)
82What are waterfalls and rapids?Waterfalls and rapids occur when there is a sudden change in the gradient of the river as it flows downstream. Waterfalls are more dramatic features than rapids and may be the result of.......
83What causes waterfalls?-A resistant band of rock occurring across the course of the river
-The edge of a plateau
-The rejuvenation of the area, giving the river renewed erosional power as sea level falls
84How does braiding occur?Braiding occurs when the river is forced to split into several channels separated by islands. It is a feature of rivers that are supplied with large loads of sand and gravel. It is most likely to occur when a river has variable discharges. The banks formed from sand and gravel are generally unstable and easily eroded.
85What is a meander?A meander is a sinuous bend in a river.
86What do you call the 'Cork-Screw Like' Movement of Water?Helicoidal Flow
87How do levees form?In the middle and lower courses, a river is at risk from flooding during times of high discharge. If it floods the velocity of the water falls as it overflows the banks. This results in deposition, because the competence of the river is suddenly reduced. This creates levees on the river banks.
88What is a Delta?A delta is a feature of deposition, located at the mouth of a river as it enters a sea or a lake. Deposition occurs as the velocity and sediment-carrying capacity of the river decrease on entering the lake or sea, and bedload and suspended material are dumped.
89What is flocculation?Flocculation is where fresh water mixes with seawater and clay particles coagulate due to chemical reaction.
90Name the Three types of DeltasCuspate
Arcuate
Birds Foot
91Describe a cuspate deltaPointed like a cup or tooth and is shaped by gentle, regular, but opposing sea currents or longshore drift
92Describe an arcuate deltaHas a curving shoreline and a dendritic pattern of drainage. Many distributaries break away from the main channel as deposition within the channel itself occurs, causing the river to braid.
93Describe a Birds Foot DeltaFingers of deposition build out into the sea along the distributaries channels, giving the appearance, from air, of a birds claw.
94What is river rejuvenation and why does it occur?Rejuvenation occurs when there is either a fall in sea level relative to the level of the land, or a rise of the land relative to the sea. This enables a river to renew its capacity to erode as its potential energy is increased.
95What is a Knick Point?A knick point is a sudden break or irregularity in the gradient along the long profile of a river. Some knick points are sharply defined, for example waterfalls, whereas others are barely noticeable.
96What is a river terrace?A river terrace is a remnant of former floodplain, which has been left at a higher level after rejuvenation of the river. Where a river renews its downcutting, it sinks its new channel into the former floodplain, leaving the old floodplain above the level of the present river.
97What is an Incised Meander?If a rejuvenated river occupies a valley with well-developed meanders, renewed energy results in them becoming incised or deepened.
98What is an Entrenched Meander?With rapid incision, where downcutting or vertical erosion dominates, the valley is more symmetrical; with steep sides and a gorge-like appearance.
TRENCH SHAPED--> U
99What is an Ingrown meander?When incision is slow and lateral erosion is occurring, an ingrown meander may be produced. The valley becomes asymmetrical, with steep cliffs on the outer bends and more gentle slip off slopes on the inner bends.
I__/
100What are the physical causes of flooding?-Excessive levels of precipitation occurring over a prolonged period of time.
-Intensive precipitation over a short period of time
-Melting of Snow
-Climatic Hazards such as cyclones in Bangladesh.
101Human Causes of Flooding-Deforestation
-Urbanisation
-Poor River Management
-Climate Change
102CASE STUDY MEDC FLOODINGCASE STUDY MEDC FLOODING
103What are the natural causes of the Elgin Floods?-Intense area of low pressure over north east Scotland
-170mm of rain in 24hours
-Ground already saturated
-Overspill- 140 cumecs
-Banks of the river collapsed
-River level was so high it spilt over the top
104Human Causes of the Elgin 2002 Floods?-Rain went straight into the river Lossie from Overland Flow
-Building on Flood Plains
-Deforestation in the upper catchment area
105What were the effects?-260 houses evacuated
-200 people taken to EHS then temporary accommodation organised
-40 OAPs moved care homes
-All roads into Elgin affected
-Railway line effected
-Car Parks under water
-Many businesses flooded
106What is the scheme which is being developed to prevent this from happening again?Flood Alleviation Scheme
107How much does it cost?£86 million
108Hard Engineering on the river lossie?Channel Straightening
Rock Armour
River Walls
109Soft Engineering?-Banks Raised
-Floodplain Left and enlarged
-Trees planted upstream in catchment area
110BANGLADESH CASE STUDYBANGLADESH CASE STUDY
111Physical Causes of these floods?-Bangladesh is in the confluence of three large rivers, it is prone to large volumes of water flowing through it
-Very low lying, the river therefore burst its banks and flooded very easily
-Cyclones and monsoons
112Human Causes of the Flooding?-Deforestation from the Himalayas
-Irrigation upstream in the Ganges caused an increase in silt deposition
-Poor planning and a rapid urbanization
113What were the Social Impacts of these Floods?-Thousands killed
-Millions made homeless
-Contaminated water lead to disease.
114Economic Impacts?-Over 900 bridges destroyed
-15000km road damaged
-Crops lost leading to food shortages
-Financial losses for businesses and shops
-Communications damaged making coordinating rescue efforts difficult
115Human Impacts?-Agricultural land flooded and contaminated by polluted waters.